2019 |
Polo, E; Ibarra-Arellano, N; Prent-Peñaloza, L; Morales-Bayuelo, A; Henao, J; Galdámez, A; Gutiérrez, M Bioorganic Chemistry, 90 (1), pp. 103034, 2019, ISSN: 0045-2068. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN31, title = {Ultrasound-Assisted Synthesis of Novel Chalcone, Heterochalcone and Bis-Chalcone Derivatives and the Evaluation of Their Antioxidant Properties and as Acetylcholinesterase Inhibitors}, author = {E Polo and N Ibarra-Arellano and L Prent-Pe\~{n}aloza and A Morales-Bayuelo and J Henao and A. Gald\'{a}mez and M Guti\'{e}rrez}, url = {http://www.sciencedirect.com/science/article/pii/S0045206819303189}, doi = {https://doi.org/10.1016/j.bioorg.2019.103034}, issn = {0045-2068}, year = {2019}, date = {2019-01-01}, journal = {Bioorganic Chemistry}, volume = {90}, number = {1}, pages = {103034}, publisher = {2011 Elsevier B. V.}, abstract = {The chalcone and bis-chalcone derivatives have been synthesized under sonication conditions via Claisen-Schmidt condensation with KOH in ethanol at room temperature (20\textendash89%). The structures were established on the basis of NMR, IR, Single-crystal XRD, and MS. The best compound 3u had inhibitory activity (IC50 = 7.50 µM). The synthesis, the antioxidative properties, chemical reactivity descriptors supported in Density Functional Theory (DFT), acetylcholinesterase (AChE) inhibition and their potential binding modes, and affinity were predicted by molecular docking of a number of morpholine-chalcones and quinoline-chalcone. A series of bis-chalcones are also reported. Molecular docking and an enzyme kinetic study on compound 3u suggested that it simultaneously binds to the catalytic active site (CAS) and peripheral anionic site (PAS) of AChE. Moreover, the pharmacokinetic profile of these compounds was investigated using a computational method.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The chalcone and bis-chalcone derivatives have been synthesized under sonication conditions via Claisen-Schmidt condensation with KOH in ethanol at room temperature (20–89%). The structures were established on the basis of NMR, IR, Single-crystal XRD, and MS. The best compound 3u had inhibitory activity (IC50 = 7.50 µM). The synthesis, the antioxidative properties, chemical reactivity descriptors supported in Density Functional Theory (DFT), acetylcholinesterase (AChE) inhibition and their potential binding modes, and affinity were predicted by molecular docking of a number of morpholine-chalcones and quinoline-chalcone. A series of bis-chalcones are also reported. Molecular docking and an enzyme kinetic study on compound 3u suggested that it simultaneously binds to the catalytic active site (CAS) and peripheral anionic site (PAS) of AChE. Moreover, the pharmacokinetic profile of these compounds was investigated using a computational method. |
Gomez-Jeria, J S Biology and Philosophy. Vi. Plato’s Cave and Homo Sapiens Inequality Artículo de revista World Journal of Research and Review,, 8 (6), pp. 23-29, 2019. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN46, title = {Biology and Philosophy. Vi. Plato’s Cave and Homo Sapiens Inequality}, author = {J.S. Gomez-Jeria}, url = {https://www.wjrr.org/download_data/WJRR0806007.pdf}, doi = {: https://doi.org/10.31871/WJRR.8.6.7}, year = {2019}, date = {2019-01-01}, journal = {World Journal of Research and Review,}, volume = {8}, number = {6}, pages = {23-29}, publisher = {2011 Elsevier B.V.}, abstract = {Poly (N,N-dimethyl-N,N-diallyl ammonium) chloride, a highly hydrophilic polyelectrolyte, was hydrophobically modified and the surface properties of the resulting amphipathic polyelectrolytes were determined. The surface activity increases with the polyelectrolyte side chain length despite the ability of this type of polyelectrolyte to form hydrophobic micro domains in solution. The standard free energy of the adsorption process, Delta G degrees(ads), were a linear function of the number of carbon atoms in the lateral chain as well as their transfer and interfacial contributions to the adsorption process with -1.73 kJ mol(-1) of methylene group to Delta G degrees(ads). From the dependence of the surface tension with the temperature the Delta S degrees(ads) was determined. The latter parameter was always positive regardless the polyelectrolyte side chain length, thus the main driving force to Delta G degrees(ads) arises from the large positive Delta S degrees(ads) values.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Poly (N,N-dimethyl-N,N-diallyl ammonium) chloride, a highly hydrophilic polyelectrolyte, was hydrophobically modified and the surface properties of the resulting amphipathic polyelectrolytes were determined. The surface activity increases with the polyelectrolyte side chain length despite the ability of this type of polyelectrolyte to form hydrophobic micro domains in solution. The standard free energy of the adsorption process, Delta G degrees(ads), were a linear function of the number of carbon atoms in the lateral chain as well as their transfer and interfacial contributions to the adsorption process with -1.73 kJ mol(-1) of methylene group to Delta G degrees(ads). From the dependence of the surface tension with the temperature the Delta S degrees(ads) was determined. The latter parameter was always positive regardless the polyelectrolyte side chain length, thus the main driving force to Delta G degrees(ads) arises from the large positive Delta S degrees(ads) values. |
Barrientos, L; Miranda-Rojas, S; Mendizabal, F Noncovalent Interactions in Inorganic Supramolecular Chemistry Based in Heavy Metals. Quantum Chemistry Point of View Artículo de revista International Journal of Quantum Chemistry, 119 (2), pp. e25675, 2019, ISSN: 0020-7608. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN61, title = {Noncovalent Interactions in Inorganic Supramolecular Chemistry Based in Heavy Metals. Quantum Chemistry Point of View}, author = {L Barrientos and S Miranda-Rojas and F. Mendizabal}, url = {https://onlinelibrary.wiley.com/doi/abs/10.1002/qua.25675}, doi = {10.1002/qua.25675}, issn = {0020-7608}, year = {2019}, date = {2019-01-01}, journal = {International Journal of Quantum Chemistry}, volume = {119}, number = {2}, pages = {e25675}, abstract = {Abstract Complexity is a concept that is being considered in chemistry as it has shown potential to reveal interesting phenomena. Thus, it is possible to study chemical phenomena in a new approach called systems chemistry. The systems chemistry has an organization and function, which are regulated by the interactions among its components. At the simplest level, noncovalent interactions between molecules can lead to the emergence of large structures. Consequently, it is possible to go from the molecular to the supramolecular systems chemistry, which aims to develop chemical systems highly complex through intra- and intermolecular forces. Proper use of the interactions previously mentioned allow a glimpse of supramolecular system chemistry in many tasks such as structural properties reflecting certain behaviors in the chemistry of materials, for example, electrical and optical, processes of molecular recognition and among others. In the last time, within this area, inorganic supramolecular systems chemistry has been developed. Those systems have a structural orientation which is defined by certain forces that predominate in the associations among molecules. It is possible to recognize these forces as hydrogen bonding, π-π stacking, halogen bonding, electrostatic, hydrophobic, charge transfer, metal coordination, and metallophilic interactions. The presence of these forces in supramolecular system yields certain properties such as light absorption and luminescence. The quantum theoretical modeling plays an important role in the designing of the supramolecular system. The goal is to apply supramolecular principles in order to understand the associated forces in many inorganic molecules that include heavy metals for instance gold, platinum, and mercury. Relevant systems will be studied in detail, considering functional aspects such as enhanced coordination of functionalized molecular self-assembly, electronic and optoelectronic properties.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract Complexity is a concept that is being considered in chemistry as it has shown potential to reveal interesting phenomena. Thus, it is possible to study chemical phenomena in a new approach called systems chemistry. The systems chemistry has an organization and function, which are regulated by the interactions among its components. At the simplest level, noncovalent interactions between molecules can lead to the emergence of large structures. Consequently, it is possible to go from the molecular to the supramolecular systems chemistry, which aims to develop chemical systems highly complex through intra- and intermolecular forces. Proper use of the interactions previously mentioned allow a glimpse of supramolecular system chemistry in many tasks such as structural properties reflecting certain behaviors in the chemistry of materials, for example, electrical and optical, processes of molecular recognition and among others. In the last time, within this area, inorganic supramolecular systems chemistry has been developed. Those systems have a structural orientation which is defined by certain forces that predominate in the associations among molecules. It is possible to recognize these forces as hydrogen bonding, π-π stacking, halogen bonding, electrostatic, hydrophobic, charge transfer, metal coordination, and metallophilic interactions. The presence of these forces in supramolecular system yields certain properties such as light absorption and luminescence. The quantum theoretical modeling plays an important role in the designing of the supramolecular system. The goal is to apply supramolecular principles in order to understand the associated forces in many inorganic molecules that include heavy metals for instance gold, platinum, and mercury. Relevant systems will be studied in detail, considering functional aspects such as enhanced coordination of functionalized molecular self-assembly, electronic and optoelectronic properties. |
Gomez-Jeria, J S; Gutierrez, Sebastian; Pizarro, Guadalupe A preliminary FTIR-ATRand XRFanalyses of the cellulose of four postcards from the Reichskommissariat Ostland and theGerman occupations of Pleskau (Russia) and Latvia Artículo de revista Chemistry Research Journal, 4 , pp. 48-57, 2019, ISSN: 2455-8990. Resumen | Enlaces | BibTeX | Etiquetas: cellulose, FTIR-ATR, German occupation of Latvia, German occupation of Russia, infrared spectroscopy, Latvia, philately, Pleskau, Postcards, raman, Reichskommissariat Ostland, Russia, Third Reich, X-Ray fluorescence, xrf @article{RN418, title = {A preliminary FTIR-ATRand XRFanalyses of the cellulose of four postcards from the Reichskommissariat Ostland and theGerman occupations of Pleskau (Russia) and Latvia}, author = {J.S. Gomez-Jeria and Sebastian Gutierrez and Guadalupe Pizarro}, url = {http://chemrj.org/download/vol-4-iss-3-2019/chemrj-2019-04-03-48-57.pdf}, issn = {2455-8990}, year = {2019}, date = {2019-01-01}, journal = {Chemistry Research Journal}, volume = {4}, pages = {48-57}, publisher = {Leon Publications}, abstract = {FTIR-ATR and XRF techniques have been employed to carry out a preliminary characterization of the cellulose of four postcards issued during the Third Reich war in the East. Two postcards were printed in Berlin while the other two corresponded to communist Russian postcards with German overprints. The XRF results show that only the paper of the German postcards contains potassium. The four postcards present Fe and Cu that could oxidize cellulose. The possible presence of cotton is suggested but not proved.}, keywords = {cellulose, FTIR-ATR, German occupation of Latvia, German occupation of Russia, infrared spectroscopy, Latvia, philately, Pleskau, Postcards, raman, Reichskommissariat Ostland, Russia, Third Reich, X-Ray fluorescence, xrf}, pubstate = {published}, tppubtype = {article} } FTIR-ATR and XRF techniques have been employed to carry out a preliminary characterization of the cellulose of four postcards issued during the Third Reich war in the East. Two postcards were printed in Berlin while the other two corresponded to communist Russian postcards with German overprints. The XRF results show that only the paper of the German postcards contains potassium. The four postcards present Fe and Cu that could oxidize cellulose. The possible presence of cotton is suggested but not proved. |
Manzano, C A; Dodder, N G; Hoh, E; Morales, R Patterns of Personal Exposure to Urban Pollutants Using Personal Passive Samplers and Gc × Gc/Tof–Ms Artículo de revista Environmental Science & Technology, 53 (2), pp. 614-624, 2019, ISSN: 0013-936X. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN59, title = {Patterns of Personal Exposure to Urban Pollutants Using Personal Passive Samplers and Gc × Gc/Tof\textendashMs}, author = {C A Manzano and N G Dodder and E Hoh and R Morales}, url = {https://doi.org/10.1021/acs.est.8b06220}, doi = {10.1021/acs.est.8b06220}, issn = {0013-936X}, year = {2019}, date = {2019-01-01}, journal = {Environmental Science & Technology}, volume = {53}, number = {2}, pages = {614-624}, abstract = {The absolute configuration of alga meroditerpenoids (-)-taondiol diacetate (1b) and (+)-epitaondiol diacetate (2c) are assigned by vibrational circular clichroism (VCD). The spectra of (2S,35,6R,7R,10R,11R,14S)-1b and (2S,3S,6S,7S,10R,11R,14s)-2c enantiomers, calculated at the B3LYP/DGDZVP and at the B3LYP/DGDZVP2 levels of theory, respectively, matched confidently with the experimental ones. The numerical approach using neighborhood similarity indexes in the CompareVOA algorithm software supports the assignments with 100% confidence. The X-ray diffraction structures of 1b and 2c were determined to verify their relative stereochemistry and the crystal stereostructure of the meroditerpenoid stypotriol triacetate (5) is also reported.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The absolute configuration of alga meroditerpenoids (-)-taondiol diacetate (1b) and (+)-epitaondiol diacetate (2c) are assigned by vibrational circular clichroism (VCD). The spectra of (2S,35,6R,7R,10R,11R,14S)-1b and (2S,3S,6S,7S,10R,11R,14s)-2c enantiomers, calculated at the B3LYP/DGDZVP and at the B3LYP/DGDZVP2 levels of theory, respectively, matched confidently with the experimental ones. The numerical approach using neighborhood similarity indexes in the CompareVOA algorithm software supports the assignments with 100% confidence. The X-ray diffraction structures of 1b and 2c were determined to verify their relative stereochemistry and the crystal stereostructure of the meroditerpenoid stypotriol triacetate (5) is also reported. |
Castro-Latorre, P; Miranda-Rojas, S; Barrientos, L; Mendizabal, F Catalytic Activity of Iron Phthalocyanine for the Oxidation of Thiocyanate and L-Cysteine Anchored on Au(111) Clusters Artículo de revista Molecular Simulation, 45 (17), pp. 1447-1453, 2019, ISSN: 0892-7022. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN62, title = {Catalytic Activity of Iron Phthalocyanine for the Oxidation of Thiocyanate and L-Cysteine Anchored on Au(111) Clusters}, author = {P Castro-Latorre and S Miranda-Rojas and L Barrientos and F. Mendizabal}, url = {https://doi.org/10.1080/08927022.2019.1654607}, doi = {10.1080/08927022.2019.1654607}, issn = {0892-7022}, year = {2019}, date = {2019-01-01}, journal = {Molecular Simulation}, volume = {45}, number = {17}, pages = {1447-1453}, abstract = {The heterologous secretion of xylanase B from Penicillium purpurogenum using glucose as inducer was performed in Aspergillus nidulans. For this purpose, plasmid pEVXB, containing the xylanase B cDNA (including its own signal peptide) under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter, was constructed and used to transform A. nidulans. Analysis of transformed clones showed that several of them secreted extracellular xylanase activity when grown in a medium containing glucose. The clone showing the highest xylanase activity was chosen for further work. When this clone was grown on glucose, xylanase activity (0.72 U/ml), was detected in the culture supernatant. This was confirmed by a zymogram analysis and by the amplification of xynB cDNA from this clone. To our knowledge, this is the first example of the production of a xylanase from Penicillium in heterologous fungal hosts using glucose as inducer.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The heterologous secretion of xylanase B from Penicillium purpurogenum using glucose as inducer was performed in Aspergillus nidulans. For this purpose, plasmid pEVXB, containing the xylanase B cDNA (including its own signal peptide) under the control of the glyceraldehyde-3-phosphate dehydrogenase promoter, was constructed and used to transform A. nidulans. Analysis of transformed clones showed that several of them secreted extracellular xylanase activity when grown in a medium containing glucose. The clone showing the highest xylanase activity was chosen for further work. When this clone was grown on glucose, xylanase activity (0.72 U/ml), was detected in the culture supernatant. This was confirmed by a zymogram analysis and by the amplification of xynB cDNA from this clone. To our knowledge, this is the first example of the production of a xylanase from Penicillium in heterologous fungal hosts using glucose as inducer. |
Gomez-Jeria, J S; Campos-Vallette, M M; Carrasco-Flores, E A; V, Gutiérrez S Raman and X-Ray Fluorescence to Identify Colors of the German Hyperinflation Stamps of the 1923 Collection Artículo de revista Journal of the Chilean Chemical Society, 64 (4), pp. 4622-4626, 2019. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN44, title = {Raman and X-Ray Fluorescence to Identify Colors of the German Hyperinflation Stamps of the 1923 Collection}, author = {J.S. Gomez-Jeria and M M Campos-Vallette and E A Carrasco-Flores and S Guti\'{e}rrez V}, url = {http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072019000404622&lng=en&nrm=iso&tlng=en}, doi = {10.4067/S0717-97072019000404622}, year = {2019}, date = {2019-01-01}, journal = {Journal of the Chilean Chemical Society}, volume = {64}, number = {4}, pages = {4622-4626}, publisher = {2011 Elsevier Inc.}, abstract = {A new solid state organometallic route to embedded nanoparticle-containing inorganic materials is shown, through pyrolysis of metal-containing derivatives of cyclotriphosphazenes. Pyrolysis in air and at 800 degrees C of new molecular precursors gives individual single-crystal nanoparticles of SiP2O7, TiO2, P4O7. WP2O7 and SiO2, depending on the precursor used. High resolution transmission electron microscopy investigations reveal, in most cases, perfect single crystals of metal oxides and the first nanostructures of negative thermal expansion metal phosphates with diameters in the range 2-6 nm for all products. While all nanoparticles are new by this method, WP2O7 and SiP2O7 nanoparticles are reported for the first time. In situ recrystallization formation of nanocrystals of SiP2O7 was also observed due to electron beam induced reactions during measurements of the nanoparticulate pyrolytic products SiO2 and P4O7. The possible mechanism for the formation of the nanoparticles at much lower temperatures than their bulk counterparts in both cases is discussed. Degrees of stabilization from the formation of P4O7 affects the nanocrystalline products: nanoparticles are observed for WP2O7, with coalescing crystallization occurring for the amorphous host in which SiP2O7 crystals form as a solid within a solid. The approach allows the simple formation of multimetallic, monometallic, metal-oxide and metal phosphate nanocrystals embedded in an amorphous dielectric. The method and can be extended to nearly any metal capable of successful coordination as an organometallic to allow embedded nanoparticle layers and features to be deposited or written on surfaces for application as high mobility pyrophosphate lithium-ion cathode materials, catalysis and nanocrystal embedded dielectric layers.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A new solid state organometallic route to embedded nanoparticle-containing inorganic materials is shown, through pyrolysis of metal-containing derivatives of cyclotriphosphazenes. Pyrolysis in air and at 800 degrees C of new molecular precursors gives individual single-crystal nanoparticles of SiP2O7, TiO2, P4O7. WP2O7 and SiO2, depending on the precursor used. High resolution transmission electron microscopy investigations reveal, in most cases, perfect single crystals of metal oxides and the first nanostructures of negative thermal expansion metal phosphates with diameters in the range 2-6 nm for all products. While all nanoparticles are new by this method, WP2O7 and SiP2O7 nanoparticles are reported for the first time. In situ recrystallization formation of nanocrystals of SiP2O7 was also observed due to electron beam induced reactions during measurements of the nanoparticulate pyrolytic products SiO2 and P4O7. The possible mechanism for the formation of the nanoparticles at much lower temperatures than their bulk counterparts in both cases is discussed. Degrees of stabilization from the formation of P4O7 affects the nanocrystalline products: nanoparticles are observed for WP2O7, with coalescing crystallization occurring for the amorphous host in which SiP2O7 crystals form as a solid within a solid. The approach allows the simple formation of multimetallic, monometallic, metal-oxide and metal phosphate nanocrystals embedded in an amorphous dielectric. The method and can be extended to nearly any metal capable of successful coordination as an organometallic to allow embedded nanoparticle layers and features to be deposited or written on surfaces for application as high mobility pyrophosphate lithium-ion cathode materials, catalysis and nanocrystal embedded dielectric layers. |
2018 |
Munoz-Gacitua, D; Garrido, C; Ruiz-Fernandez, A; Ahumada, H; Campos-Vallette, M; Araya-Maturana, R; Weiss-Lopez, B Molecular Dynamics Characterization of Silver Colloidal Interfaces for Sers Applications. Gallic Acid Test Artículo de revista Journal of Raman Spectroscopy, 49 (2), pp. 256-261, 2018, ISSN: 0377-0486. Resumen | Enlaces | BibTeX | Etiquetas: colloid, crystal dynamics, gallic molecular nanoparticles, pair potentials, sampling, sers, silver spectroscopy, umbrella @article{RN407, title = {Molecular Dynamics Characterization of Silver Colloidal Interfaces for Sers Applications. Gallic Acid Test}, author = { D. Munoz-Gacitua and C. Garrido and A. Ruiz-Fernandez and H. Ahumada and M. Campos-Vallette and R. Araya-Maturana and B. Weiss-Lopez}, url = {/brokenurl#<Go to ISI>://WOS:000425020500007}, doi = {10.1002/jrs.5274}, issn = {0377-0486}, year = {2018}, date = {2018-01-01}, journal = {Journal of Raman Spectroscopy}, volume = {49}, number = {2}, pages = {256-261}, abstract = {One of the most useful applications of silver colloidal solutions is in surface-enhanced Raman spectroscopy (SERS), because the amplification factor of about 10(6) allows the vibrational study and detection of highly diluted species in aqueous environment, and more recently in early diagnosis of cancer and imaging. A useful colloid for SERS is that reported by Leopold and Lendl (Colloid1). However, SERS response from anions or rich electron density molecules has been difficult to obtain in this colloid. Recently, a minor modification of the surface charge density (Colloid 2) allowed to observe reproducible SERS spectrum from gallate anion (GA(-)). In this work, the structure of both solid and solution interfaces were characterized using molecular dynamics. Experimental values of -potentials were reproduced by simulations, and the chemical potential of GA(-) approaching both interfaces was calculated using umbrella sampling and the weighted histograms analisys methodology (WHAM). The calculated barrier to approach the interface of Colloid 1 is 2.8kJmol(-1) greater than in Colloid 2, and the stability of GA(-) with Colloid 2 at the minimum is 3.5kJmol(-1) more stable than with Colloid 1. Finally, the calculated average orientation of GA(-) adsorbed onto the colloidal surface is in excellent agreement with the experimental SERS observations.}, keywords = {colloid, crystal dynamics, gallic molecular nanoparticles, pair potentials, sampling, sers, silver spectroscopy, umbrella}, pubstate = {published}, tppubtype = {article} } One of the most useful applications of silver colloidal solutions is in surface-enhanced Raman spectroscopy (SERS), because the amplification factor of about 10(6) allows the vibrational study and detection of highly diluted species in aqueous environment, and more recently in early diagnosis of cancer and imaging. A useful colloid for SERS is that reported by Leopold and Lendl (Colloid1). However, SERS response from anions or rich electron density molecules has been difficult to obtain in this colloid. Recently, a minor modification of the surface charge density (Colloid 2) allowed to observe reproducible SERS spectrum from gallate anion (GA(-)). In this work, the structure of both solid and solution interfaces were characterized using molecular dynamics. Experimental values of -potentials were reproduced by simulations, and the chemical potential of GA(-) approaching both interfaces was calculated using umbrella sampling and the weighted histograms analisys methodology (WHAM). The calculated barrier to approach the interface of Colloid 1 is 2.8kJmol(-1) greater than in Colloid 2, and the stability of GA(-) with Colloid 2 at the minimum is 3.5kJmol(-1) more stable than with Colloid 1. Finally, the calculated average orientation of GA(-) adsorbed onto the colloidal surface is in excellent agreement with the experimental SERS observations. |
Briones, X; Tapia, R A; Campodonico, P R; Urzúa, M; Leiva, A; Contreras, R; González-Navarrete, J Synthesis and Characterization of Poly (Ionic Liquid) Derivatives of N -Alkyl Quaternized Poly(4-Vinylpyridine) Artículo de revista Reactive & Functional Polymers, 124 , pp. 64-71, 2018, ISSN: 1381-5148. Resumen | Enlaces | BibTeX | Etiquetas: bromide, carbon, chromium chromium, composite, liquid), liquid)s, removal, retention, salts, separation, water @article{RN406, title = {Synthesis and Characterization of Poly (Ionic Liquid) Derivatives of N -Alkyl Quaternized Poly(4-Vinylpyridine)}, author = { X. Briones and R.A. Tapia and P.R. Campodonico and M. Urz\'{u}a and A. Leiva and R. Contreras and J. Gonz\'{a}lez-Navarrete}, url = {/brokenurl#<Go to ISI>://WOS:000429499900008}, doi = {10.1016/j.reactfunctpolym.2018.01.003}, issn = {1381-5148}, year = {2018}, date = {2018-01-01}, journal = {Reactive & Functional Polymers}, volume = {124}, pages = {64-71}, abstract = {The main motivation of this work is to obtain poly (ionic liquids) (PILs) derived from poly (4-vinyl pyridine) of different hydrophobic character containing BF4-, PF6-, (CF3SO2)(2) N- and CF3SO3- as counterions. PILs were synthesized from N -alkyl quaternized poly(4-vinylpyridine) P-4VP(+) -CnBr- with different alkyl chain length}, keywords = {bromide, carbon, chromium chromium, composite, liquid), liquid)s, removal, retention, salts, separation, water}, pubstate = {published}, tppubtype = {article} } The main motivation of this work is to obtain poly (ionic liquids) (PILs) derived from poly (4-vinyl pyridine) of different hydrophobic character containing BF4-, PF6-, (CF3SO2)(2) N- and CF3SO3- as counterions. PILs were synthesized from N -alkyl quaternized poly(4-vinylpyridine) P-4VP(+) -CnBr- with different alkyl chain length |
Diaz, C; Carrillo, D; Campa, De La R; Soto, A P; Valenzuela, M L Solid-State Synthesis of Lnocl/Ln(2)O(3) (Ln = Eu, Nd) by Using Chitosan and Ps-Co-P4vp as Polymeric Supports Artículo de revista Journal of Rare Earths, 36 (12), pp. 1326-1332, 2018, ISSN: 1002-0721. Resumen | Enlaces | BibTeX | Etiquetas: earths, euocl/eu2o3, lanthanide, lanthanides, luminescence, method, nanocrystals, ndocl, oxides, rare scale solventless supracrystals @article{RN397, title = {Solid-State Synthesis of Lnocl/Ln(2)O(3) (Ln = Eu, Nd) by Using Chitosan and Ps-Co-P4vp as Polymeric Supports}, author = { C. Diaz and D. Carrillo and R. De La Campa and A.P. Soto and M.L. Valenzuela}, url = {/brokenurl#<Go to ISI>://WOS:000451031200013}, doi = {10.1016/j.jre.2018.03.031}, issn = {1002-0721}, year = {2018}, date = {2018-01-01}, journal = {Journal of Rare Earths}, volume = {36}, number = {12}, pages = {1326-1332}, publisher = {2018 Chinese Society of Rare Earths. Published by Elsevier B.V.}, abstract = {A series of lanthanide materials of type LnOCl or Ln(2)O(3) (Ln = Eu, Nd) were successfully prepared via a convenient and straightforward two-step procedure. Firstly, and by using chitosan and PS-co-P4VP as polymeric supports, macromolecular complexes of type chitosan LnCl(3) and PS-co-P4VP center dot LnCl(3) were prepared. These macromolecular complexes were treated in solid state at 800 degrees C under air, leading to the corresponding LnOCl or Ln(2)O(3) materials (Ln = Eu, Nd) with moderate to good yields. The nature of the as-prepared lanthanide materials (LnCl and/or Ln(2)O(3)) is strongly influenced by the polymeric template (i.e., chitosan or PS-co-P4VP), the lanthanide salt precursor, and the polymer/lanthanide molar ratio. Thus, when chitosan center dot LnCl(3) and PS-co-P4VP center dot EuCl3 are used as macromolecular precursors, a mixture of crystalline phases o f both EuOCl and Eu2O3 are obtained. However, when chitosan center dot NdCl3 and PS-co-P4VP center dot NdCl3 are used, a sole pure crystalline phase of NdOCl is obtained. The nanostructured lanthanide materials were characterized by means of XRD (X-ray diffraction of powder), SEM, EDS, TEM, and HRTEM. The luminescent spectra of the as-prepared EuOCl/Eu2O3 mixture materials show an emission pattern whose intensity is strongly influenced by the nature of the polymeric precursor, as well as on the metal/polymer molar ratios.}, keywords = {earths, euocl/eu2o3, lanthanide, lanthanides, luminescence, method, nanocrystals, ndocl, oxides, rare scale solventless supracrystals}, pubstate = {published}, tppubtype = {article} } A series of lanthanide materials of type LnOCl or Ln(2)O(3) (Ln = Eu, Nd) were successfully prepared via a convenient and straightforward two-step procedure. Firstly, and by using chitosan and PS-co-P4VP as polymeric supports, macromolecular complexes of type chitosan LnCl(3) and PS-co-P4VP center dot LnCl(3) were prepared. These macromolecular complexes were treated in solid state at 800 degrees C under air, leading to the corresponding LnOCl or Ln(2)O(3) materials (Ln = Eu, Nd) with moderate to good yields. The nature of the as-prepared lanthanide materials (LnCl and/or Ln(2)O(3)) is strongly influenced by the polymeric template (i.e., chitosan or PS-co-P4VP), the lanthanide salt precursor, and the polymer/lanthanide molar ratio. Thus, when chitosan center dot LnCl(3) and PS-co-P4VP center dot EuCl3 are used as macromolecular precursors, a mixture of crystalline phases o f both EuOCl and Eu2O3 are obtained. However, when chitosan center dot NdCl3 and PS-co-P4VP center dot NdCl3 are used, a sole pure crystalline phase of NdOCl is obtained. The nanostructured lanthanide materials were characterized by means of XRD (X-ray diffraction of powder), SEM, EDS, TEM, and HRTEM. The luminescent spectra of the as-prepared EuOCl/Eu2O3 mixture materials show an emission pattern whose intensity is strongly influenced by the nature of the polymeric precursor, as well as on the metal/polymer molar ratios. |
Lodeiro, L; Contreras, R; Ormazabal-Toledo, R How Meaningful Is the Halogen Bonding in 1-Ethyl-3-Methyl Imidazolium-Based Ionic Liquids for Co2 Capture? Artículo de revista Journal of Physical Chemistry B, 122 (32), pp. 7907-7914, 2018, ISSN: 1520-6106. Resumen | Enlaces | BibTeX | Etiquetas: atmospheric carbon-dioxide, co2, conversion, dynamics, field, hydrogen-bonds, mechanism molecular-force reactivity, solubility, solvents @article{RN419, title = {How Meaningful Is the Halogen Bonding in 1-Ethyl-3-Methyl Imidazolium-Based Ionic Liquids for Co2 Capture?}, author = { L. Lodeiro and R. Contreras and R. Ormazabal-Toledo}, url = {/brokenurl#<Go to ISI>://WOS:000442437700011}, doi = {10.1021/acs.jpcb.8b04990}, issn = {1520-6106}, year = {2018}, date = {2018-01-01}, journal = {Journal of Physical Chemistry B}, volume = {122}, number = {32}, pages = {7907-7914}, abstract = {We report on several parameters that can be used to describe the 1-ethyl-3-methyl-4,5-(X-2)imidazolium cations (where X = H, Br, and I) within the Canongia-Lopez and Padua Force Field (CL&P) framework. Geometrical parameters like intramolecular distances and radial distribution functions are close to the experimental structure. Density values obtained with our force field are within the expected ones from CL&P calculations in related systems. This information is used to simulate through molecular dynamics the solubilization of CO2 by these ILs. For pure ILs, the addition of halides in position 4 and 5 promotes an enhanced hydrogen bond interaction at position 2 with the oxygen atoms in the anion. It is found that CO2 should be in the interstices of the anion-cation 3D network with longer distances than those found in other reports at ab initio levels, suggesting that halogen bond, if present, may be not the driving force interaction in these systems. Therefore, it seems that CO2 interacts linearly via an oxygen atom with the cation and with the anion through a pi-stacking or hydrogen-bonded fashions. Solvation enthalpies compare well with the experimental data, thereby suggesting that halogenated ILs dissolve more efficiently in CO2 than C(2)C(1)Im(+) derivatives. This result suggests that halogenated ILs can be considered as reliable candidates for CO2 capture.}, keywords = {atmospheric carbon-dioxide, co2, conversion, dynamics, field, hydrogen-bonds, mechanism molecular-force reactivity, solubility, solvents}, pubstate = {published}, tppubtype = {article} } We report on several parameters that can be used to describe the 1-ethyl-3-methyl-4,5-(X-2)imidazolium cations (where X = H, Br, and I) within the Canongia-Lopez and Padua Force Field (CL&P) framework. Geometrical parameters like intramolecular distances and radial distribution functions are close to the experimental structure. Density values obtained with our force field are within the expected ones from CL&P calculations in related systems. This information is used to simulate through molecular dynamics the solubilization of CO2 by these ILs. For pure ILs, the addition of halides in position 4 and 5 promotes an enhanced hydrogen bond interaction at position 2 with the oxygen atoms in the anion. It is found that CO2 should be in the interstices of the anion-cation 3D network with longer distances than those found in other reports at ab initio levels, suggesting that halogen bond, if present, may be not the driving force interaction in these systems. Therefore, it seems that CO2 interacts linearly via an oxygen atom with the cation and with the anion through a pi-stacking or hydrogen-bonded fashions. Solvation enthalpies compare well with the experimental data, thereby suggesting that halogenated ILs dissolve more efficiently in CO2 than C(2)C(1)Im(+) derivatives. This result suggests that halogenated ILs can be considered as reliable candidates for CO2 capture. |
Salgado, F; Caballero, J; Vargas, R; Cornejo, A; Areche, C Natural Product Research, 10.1080/14786419.2018.1492576 , pp. 1-5, 2018, ISSN: 1478-6419. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN381, title = {Continental and Antarctic Lichens: Isolation, Identification and Molecular Modeling of the Depside Tenuiorin from the Antarctic Lichen Umbilicaria Antarctica as Tau Protein Inhibitor}, author = { F. Salgado and J. Caballero and R. Vargas and A. Cornejo and C. Areche}, url = {/brokenurl#10.1080/14786419.2018.1492576}, doi = {10.1080/14786419.2018.1492576}, issn = {1478-6419}, year = {2018}, date = {2018-01-01}, journal = {Natural Product Research}, volume = {10.1080/14786419.2018.1492576}, pages = {1-5}, abstract = {AbstractAlzheimer?s disease (AD) is the most common form of dementia involving A? and tau protein. So far, AD cure remains elusive, but considering that AD progresses throughout tau pathology, which turns tau protein an appropriate target, besides tau is also included in other neurodegenerative disorders named as tauopathies. Here, we have isolated seventeen compounds belonging to six lichens species. Due to scarce of spectroscopic data of the compound 5,7-dihydroxy-6-methylphthalide, we explained their structural elucidation based on NMR data. In this study, we show that only tenuiorin from Umbilicaria antarctica inhibited 50% of tau 4R at 100?µM. Then, we shown that molecular interactions of tenuiorin with the steric zipper model of the hexapeptide 306VQIVYK311 were studied by docking calculations and the results suggested that tenuiorin forms both hydrogen bonds with lysine and glutamine side chains and forms several hydrophobic interactions with valine and lysine from 306VQIVYK311 motif.}, keywords = {}, pubstate = {published}, tppubtype = {article} } AbstractAlzheimer?s disease (AD) is the most common form of dementia involving A? and tau protein. So far, AD cure remains elusive, but considering that AD progresses throughout tau pathology, which turns tau protein an appropriate target, besides tau is also included in other neurodegenerative disorders named as tauopathies. Here, we have isolated seventeen compounds belonging to six lichens species. Due to scarce of spectroscopic data of the compound 5,7-dihydroxy-6-methylphthalide, we explained their structural elucidation based on NMR data. In this study, we show that only tenuiorin from Umbilicaria antarctica inhibited 50% of tau 4R at 100?µM. Then, we shown that molecular interactions of tenuiorin with the steric zipper model of the hexapeptide 306VQIVYK311 were studied by docking calculations and the results suggested that tenuiorin forms both hydrogen bonds with lysine and glutamine side chains and forms several hydrophobic interactions with valine and lysine from 306VQIVYK311 motif. |
Rojano, R E; Manzano, C A; Toro, R; Morales, R G E; Restrepo, G; Leiva, M A Potential Local and Regional Impacts of Particulate Matter Emitted from One of the World's Largest Open-Pit Coal Mines Artículo de revista Air Quality Atmosphere and Health, 11 (5), pp. 601-610, 2018, ISSN: 1873-9318. Resumen | Enlaces | BibTeX | Etiquetas: air-pollution, area, atmospheric cerrejon, china, cities colombia, environmental chemistry, episodes, health impact, long-range mining mining, open-pit origin, particulatematter, pm10, quality, temporal transport, trends @article{RN417, title = {Potential Local and Regional Impacts of Particulate Matter Emitted from One of the World's Largest Open-Pit Coal Mines}, author = { R.E. Rojano and C.A. Manzano and R. Toro and R.G.E. Morales and G. Restrepo and M.A. Leiva}, url = {/brokenurl#<Go to ISI>://WOS:000435421100011}, doi = {10.1007/s11869-017-0542-4}, issn = {1873-9318}, year = {2018}, date = {2018-01-01}, journal = {Air Quality Atmosphere and Health}, volume = {11}, number = {5}, pages = {601-610}, abstract = {This study was designed to evaluate the atmospheric total suspended particle (TSP) and particulate matter (PM10) concentrations and temporal variability in one of the world's largest open-pit coal mines (El Cerrejon) located in northeast Colombia, during 2012-2016. The results showed overall average TSP and PM10 concentrations of 86 mu g m (-3) (CI95% 84-88 mu g m (-3)) and 34 mu g m (-3) (CI95% 33-35 mu g m (-3)), respectively, with the highest concentrations between March and August each year. A time trend analysis of the results revealed that PM10 concentrations in particular have significantly increased between 6.2 and 7.7% per year (CI95% 1.2-12.8% year(-1)) in several of the monitoring stations. Meteorological parameters were also evaluated. It was observed that NE winds with speeds above 2 m s(-1) were significantly correlated with an increase in the concentration of PM10 for selected downwind sites, which suggested that coal mining operations are an important source of atmospheric PM in the area. Regional long-range atmospheric transport scenarios showed potential effects on neighboring municipalities and countries within 72-h transportation events. These highlighted the need to develop new strategies to control the emissions of PM from the local mining industry to comply with local and international guidelines and regulations, particularly when industrial expansion is planned for the near future and relatively large population centers are in the area, of which a high proportion belong to indigenous populations.}, keywords = {air-pollution, area, atmospheric cerrejon, china, cities colombia, environmental chemistry, episodes, health impact, long-range mining mining, open-pit origin, particulatematter, pm10, quality, temporal transport, trends}, pubstate = {published}, tppubtype = {article} } This study was designed to evaluate the atmospheric total suspended particle (TSP) and particulate matter (PM10) concentrations and temporal variability in one of the world's largest open-pit coal mines (El Cerrejon) located in northeast Colombia, during 2012-2016. The results showed overall average TSP and PM10 concentrations of 86 mu g m (-3) (CI95% 84-88 mu g m (-3)) and 34 mu g m (-3) (CI95% 33-35 mu g m (-3)), respectively, with the highest concentrations between March and August each year. A time trend analysis of the results revealed that PM10 concentrations in particular have significantly increased between 6.2 and 7.7% per year (CI95% 1.2-12.8% year(-1)) in several of the monitoring stations. Meteorological parameters were also evaluated. It was observed that NE winds with speeds above 2 m s(-1) were significantly correlated with an increase in the concentration of PM10 for selected downwind sites, which suggested that coal mining operations are an important source of atmospheric PM in the area. Regional long-range atmospheric transport scenarios showed potential effects on neighboring municipalities and countries within 72-h transportation events. These highlighted the need to develop new strategies to control the emissions of PM from the local mining industry to comply with local and international guidelines and regulations, particularly when industrial expansion is planned for the near future and relatively large population centers are in the area, of which a high proportion belong to indigenous populations. |
Vetterlein, C; Vasquez, R; Bolanos, K; Acosta, G A; Guzman, F; Albericio, F; Celis, F; Campos-Vallette, M; Kogan, M J; Araya, E Exploring the Influence of Diels-Alder Linker Length on Photothermal Molecule Release from Gold Nanorods Artículo de revista Colloids and Surfaces B-Biointerfaces, 166 , pp. 323-329, 2018, ISSN: 0927-7765. Resumen | Enlaces | BibTeX | Etiquetas: controlled drug-delivery, effect, enhanced fluorescence, micelles, nanoparticles, peptide photothermal polymeric raman-scattering, release, spatial temporal @article{RN410, title = {Exploring the Influence of Diels-Alder Linker Length on Photothermal Molecule Release from Gold Nanorods}, author = { C. Vetterlein and R. Vasquez and K. Bolanos and G.A. Acosta and F. Guzman and F. Albericio and F. Celis and M. Campos-Vallette and M.J. Kogan and E. Araya}, url = {/brokenurl#<Go to ISI>://WOS:000432505900038}, doi = {10.1016/j.colsurfb.2018.03.021}, issn = {0927-7765}, year = {2018}, date = {2018-01-01}, journal = {Colloids and Surfaces B-Biointerfaces}, volume = {166}, pages = {323-329}, publisher = {2018 Elsevier B.V.}, abstract = {We studied the photothermal release of carboxyfluorescein (CF) linked to the gold surface of gold nanorods (GNRs) by two Diels-Alder adducts of different lengths (n = 4 and n = 9). The functionalized GNRs were irradiated with infrared light to produce photothermal release of CF by a retro-Diels-Alder reaction. The adducts were chemisorbed on the GNRs and the functionalized nanoparticles were characterized by UV-vis, DLS, zeta potential and Raman and surface-enhanced Raman spectroscopy (SEAS). On the basis of the degree of nanoparticle functionalization and the SERS results, we inferred the orientation of CF on the surface of the gold nanoparticle. Moreover, we determined the photothermal release profiles of CF from the gold surface by laser irradiation. The release was faster for the longer linker (n = 9). SERS revealed that, for the shorter linker (n = 4), molecules are oriented perpendicularly with respect to the gold surface, thereby maintaining the CF far from the surface. In contrast, the longer linker was observed to be tilted, thus maintaining CF close to the gold surface and therefore potentially favoring the photothermal transfer of energy. These results are relevant for the future development of the spatial and temporal controlled release of drugs by means of gold nanoparticles.}, keywords = {controlled drug-delivery, effect, enhanced fluorescence, micelles, nanoparticles, peptide photothermal polymeric raman-scattering, release, spatial temporal}, pubstate = {published}, tppubtype = {article} } We studied the photothermal release of carboxyfluorescein (CF) linked to the gold surface of gold nanorods (GNRs) by two Diels-Alder adducts of different lengths (n = 4 and n = 9). The functionalized GNRs were irradiated with infrared light to produce photothermal release of CF by a retro-Diels-Alder reaction. The adducts were chemisorbed on the GNRs and the functionalized nanoparticles were characterized by UV-vis, DLS, zeta potential and Raman and surface-enhanced Raman spectroscopy (SEAS). On the basis of the degree of nanoparticle functionalization and the SERS results, we inferred the orientation of CF on the surface of the gold nanoparticle. Moreover, we determined the photothermal release profiles of CF from the gold surface by laser irradiation. The release was faster for the longer linker (n = 9). SERS revealed that, for the shorter linker (n = 4), molecules are oriented perpendicularly with respect to the gold surface, thereby maintaining the CF far from the surface. In contrast, the longer linker was observed to be tilted, thus maintaining CF close to the gold surface and therefore potentially favoring the photothermal transfer of energy. These results are relevant for the future development of the spatial and temporal controlled release of drugs by means of gold nanoparticles. |
Gomez-Jeria, J S; Kpotin, G A Some Remarks on the Interpretation of the Local Atomic Reactivity Indices within the Klopman-Peradejordi-Gomez (Kpg) Method. I. Theoretical Analysis Artículo de revista Research Journal of Pharmaceutical Biological and Chemical Sciences, 9 (1), pp. 550-561, 2018, ISSN: 0975-8585. Resumen | Enlaces | BibTeX | Etiquetas: atomic capacity, charge charge, chemical electrophilicity, hardness, indices, klopman-peradejordi-gomez local method, net orientational parameter, proposed qsar, reactivity reactivity, softness, superdelocalizability, tables values @article{RN424, title = {Some Remarks on the Interpretation of the Local Atomic Reactivity Indices within the Klopman-Peradejordi-Gomez (Kpg) Method. I. Theoretical Analysis}, author = { J.S. Gomez-Jeria and G.A. Kpotin}, url = {/brokenurl#<Go to ISI>://WOS:000428942500075}, doi = {DOI 10.23913/ride.v9i17.395}, issn = {0975-8585}, year = {2018}, date = {2018-01-01}, journal = {Research Journal of Pharmaceutical Biological and Chemical Sciences}, volume = {9}, number = {1}, pages = {550-561}, abstract = {The Klopman-Peradejordi-Gomez method relates the variation of a biological activity, measured in vivo or in vitro, with the variation of the numerical values of a set of local atomic reactivity indices (LARIs). The introduction of local atomic reactivity indices within the Hartree-Fock scheme plus the orientational parameter of the substituents has produced excellent relationships between the electronic structure and the biological activity for many different molecules and biological measurements. Here we present a detailed analysis of how to modify the numerical values of the LARIs in order to increase the biological activity. The concept of local molecular orbital is central to this analysis.}, keywords = {atomic capacity, charge charge, chemical electrophilicity, hardness, indices, klopman-peradejordi-gomez local method, net orientational parameter, proposed qsar, reactivity reactivity, softness, superdelocalizability, tables values}, pubstate = {published}, tppubtype = {article} } The Klopman-Peradejordi-Gomez method relates the variation of a biological activity, measured in vivo or in vitro, with the variation of the numerical values of a set of local atomic reactivity indices (LARIs). The introduction of local atomic reactivity indices within the Hartree-Fock scheme plus the orientational parameter of the substituents has produced excellent relationships between the electronic structure and the biological activity for many different molecules and biological measurements. Here we present a detailed analysis of how to modify the numerical values of the LARIs in order to increase the biological activity. The concept of local molecular orbital is central to this analysis. |
Arriaza, B; Ogalde, J P; Campos-Vallette, M; Paipa, C; Leyton, P; Lara, N Toxic Pigment in a Capacocha Burial: Instrumental Identification of Cinnabar in Inca Human Remains from Iquique, Chile Artículo de revista Archaeometry, 60 (6), pp. 1324-1333, 2018, ISSN: 0003-813x. Resumen | Enlaces | BibTeX | Etiquetas: ancient cerro coast esmeralda, exposure, hematite, insight, mercury mercury, mortuary nasca, pigments, poisoning, pottery, raman red rituals, sem, soils, spectroscopy @article{RN408, title = {Toxic Pigment in a Capacocha Burial: Instrumental Identification of Cinnabar in Inca Human Remains from Iquique, Chile}, author = { B. Arriaza and J.P. Ogalde and M. Campos-Vallette and C. Paipa and P. Leyton and N. Lara}, url = {/brokenurl#<Go to ISI>://WOS:000449888500012}, doi = {10.1111/arcm.12392}, issn = {0003-813x}, year = {2018}, date = {2018-01-01}, journal = {Archaeometry}, volume = {60}, number = {6}, pages = {1324-1333}, abstract = {We report on the analysis of a red pigment found in a lavish Inca burial from Cerro Esmeralda, Chile, associated with the human sacrifice of two young girls. The outcome shows that the red pigment is mainly cinnabar, with 95% of HgS content. Cinnabar is rarely found in the archaeological record of Chile. Thus, we propose that our results are another line of evidence supporting Iquique's Cerro Esmeralda inhumation as a unique Inca ritual. It was a special lower-elevation capacocha burial, most probably undertaken to politically and symbolically incorporate the coastal people into the Tawantinsuyo Empire.}, keywords = {ancient cerro coast esmeralda, exposure, hematite, insight, mercury mercury, mortuary nasca, pigments, poisoning, pottery, raman red rituals, sem, soils, spectroscopy}, pubstate = {published}, tppubtype = {article} } We report on the analysis of a red pigment found in a lavish Inca burial from Cerro Esmeralda, Chile, associated with the human sacrifice of two young girls. The outcome shows that the red pigment is mainly cinnabar, with 95% of HgS content. Cinnabar is rarely found in the archaeological record of Chile. Thus, we propose that our results are another line of evidence supporting Iquique's Cerro Esmeralda inhumation as a unique Inca ritual. It was a special lower-elevation capacocha burial, most probably undertaken to politically and symbolically incorporate the coastal people into the Tawantinsuyo Empire. |
Sanchez, B; Calderon, C; Garrido, C; Contreras, R; Campodonico, P R Solvent Effect on a Model Snar Reaction in Ionic Liquid/Water Mixtures at Different Compositions Artículo de revista New Journal of Chemistry, 42 (12), pp. 9645-9650, 2018, ISSN: 1144-0546. Resumen | Enlaces | BibTeX | Etiquetas: aromatic binary-mixtures, catalysis, kinetics liquids, mixed-solvents, molecules, nitro-group, nucleophilic-substitution, preferential solvation, water @article{RN421, title = {Solvent Effect on a Model Snar Reaction in Ionic Liquid/Water Mixtures at Different Compositions}, author = { B. Sanchez and C. Calderon and C. Garrido and R. Contreras and P.R. Campodonico}, url = {/brokenurl#<Go to ISI>://WOS:000435298100034}, doi = {10.1039/c7nj04820c}, issn = {1144-0546}, year = {2018}, date = {2018-01-01}, journal = {New Journal of Chemistry}, volume = {42}, number = {12}, pages = {9645-9650}, abstract = {The reaction of phenyl 2,4,6-trinitrophenyl ether and piperidine was kinetically evaluated in BMIMBF4/water mixtures as the reaction media. This study shows the dramatic effect of the mixture composition on the reacting pair and its reaction rate, highlighting two strongly demarcated zones. The first one, rich in water, is characterized by strong variations in the rate coefficient values, suggesting the presence of preferential solvent effects in the aqueous phase. The second zone shows high rate coefficient values independent of the composition of the solvent mixture, suggesting predominant anion solvent effects. These results were validated using fluorescence spectroscopy and the Kamlet-Taft parameter.}, keywords = {aromatic binary-mixtures, catalysis, kinetics liquids, mixed-solvents, molecules, nitro-group, nucleophilic-substitution, preferential solvation, water}, pubstate = {published}, tppubtype = {article} } The reaction of phenyl 2,4,6-trinitrophenyl ether and piperidine was kinetically evaluated in BMIMBF4/water mixtures as the reaction media. This study shows the dramatic effect of the mixture composition on the reacting pair and its reaction rate, highlighting two strongly demarcated zones. The first one, rich in water, is characterized by strong variations in the rate coefficient values, suggesting the presence of preferential solvent effects in the aqueous phase. The second zone shows high rate coefficient values independent of the composition of the solvent mixture, suggesting predominant anion solvent effects. These results were validated using fluorescence spectroscopy and the Kamlet-Taft parameter. |
Figueroa-Millon, S; Alvarez-Serrano, I; Berardan, D; Galdámez, A Synthesis and Transport Properties of P-Type Lead-Free Agsnmsbse2tem Thermoelectric Systems Artículo de revista Materials Chemistry and Physics, 211 , pp. 321-328, 2018, ISSN: 0254-0584. Resumen | Enlaces | BibTeX | Etiquetas: agpbmsbte2+m, chemical diffraction, efficiency, electron figure, high hrtem, materials, merit, microscopy nanostructured performance, synthesis, thermoelectric thermoelectrics, transmission x-ray x=0 @article{RN400, title = {Synthesis and Transport Properties of P-Type Lead-Free Agsnmsbse2tem Thermoelectric Systems}, author = { S. Figueroa-Millon and I. Alvarez-Serrano and D. Berardan and A. Gald\'{a}mez}, url = {/brokenurl#<Go to ISI>://WOS:000430774300040}, doi = {10.1016/j.matchemphys.2018.02.047}, issn = {0254-0584}, year = {2018}, date = {2018-01-01}, journal = {Materials Chemistry and Physics}, volume = {211}, pages = {321-328}, publisher = {2018 Elsevier B.V.}, abstract = {We report the synthesis, characterization and thermoelectric properties of lead-free AgSnmSbSe2Tem (m = 2 and 10) systems. Powder X-ray diffraction patterns and Rietveld refinement results were consistent with phases belonging to the Pm (3) over barm space group. The microstructures and morphologies of these systems were investigated using scanning electron microcopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Parallelepiped bars for transport measurements were prepared using two methods: the classical method (CM) from melted samples and the spark plasma sintering (SPS). The AgSnmSbSe2Tem (m = 2 and 10) systems exhibited typical degenerate semiconductor behavior, with a carrier concentration of approximately +10(21) cm(-3). We determined that the Seebeck coefficient can be substantially increased from approximately +40 V K-1 (CM) to +70 mu V K-1 (SPS) in AgSn2SbSe2Te2 at room temperature. Consequently, the power factor (S(2)cr) was similar to 22 W cm(-1) K-2. On the basis of the electrical and thermal transport properties, ZT values of similar to 0.10 were obtained at room temperature.}, keywords = {agpbmsbte2+m, chemical diffraction, efficiency, electron figure, high hrtem, materials, merit, microscopy nanostructured performance, synthesis, thermoelectric thermoelectrics, transmission x-ray x=0}, pubstate = {published}, tppubtype = {article} } We report the synthesis, characterization and thermoelectric properties of lead-free AgSnmSbSe2Tem (m = 2 and 10) systems. Powder X-ray diffraction patterns and Rietveld refinement results were consistent with phases belonging to the Pm (3) over barm space group. The microstructures and morphologies of these systems were investigated using scanning electron microcopy (SEM) and high-resolution transmission electron microscopy (HRTEM). Parallelepiped bars for transport measurements were prepared using two methods: the classical method (CM) from melted samples and the spark plasma sintering (SPS). The AgSnmSbSe2Tem (m = 2 and 10) systems exhibited typical degenerate semiconductor behavior, with a carrier concentration of approximately +10(21) cm(-3). We determined that the Seebeck coefficient can be substantially increased from approximately +40 V K-1 (CM) to +70 mu V K-1 (SPS) in AgSn2SbSe2Te2 at room temperature. Consequently, the power factor (S(2)cr) was similar to 22 W cm(-1) K-2. On the basis of the electrical and thermal transport properties, ZT values of similar to 0.10 were obtained at room temperature. |
Rojas-Aedo, J F; Gil-Duran, C; Goity, A; Vaca, I; Levican, G; Larrondo, L F; Chavez, R The Developmental Regulator Pcz1 Affects the Production of Secondary Metabolites in the Filamentous Fungus Penicillium Roqueforti Artículo de revista Microbiological Research, 212 , pp. 67-74, 2018, ISSN: 0944-5013. Resumen | Enlaces | BibTeX | Etiquetas: biosynthesis, chrysogenum complex, cross-talk, discovery, expression, gene-cluster, laea, metabolism, mycophenolic-acid, pathway pcz1, penicillium protein, roqueforti, secondary subunit @article{RN382, title = {The Developmental Regulator Pcz1 Affects the Production of Secondary Metabolites in the Filamentous Fungus Penicillium Roqueforti}, author = { J.F. Rojas-Aedo and C. Gil-Duran and A. Goity and I. Vaca and G. Levican and L.F. Larrondo and R. Chavez}, url = {/brokenurl#<Go to ISI>://WOS:000438320100007}, doi = {10.1016/j.micres.2018.05.005}, issn = {0944-5013}, year = {2018}, date = {2018-01-01}, journal = {Microbiological Research}, volume = {212}, pages = {67-74}, abstract = {Penicillium roqueforti is used in the production of several kinds of ripened blue-veined cheeses. In addition, this fungus produces interesting secondary metabolites such as roquefortine C, andrastin A and mycophenolic acid. To date, there is scarce information concerning the regulation of the production of these secondary metabolites. Recently, the gene named pcz1 (Penicillium C6 zinc domain protein 1) was described in P. roqueforti, which encodes for a Zn(II)(2)Cys(6) protein that controls growth and developmental processes in this fungus. However, its effect on secondary metabolism is currently unknown. In this work, we have analyzed how the overexpression and down-regulation of pcz1 affect the production of roquefortine C, andrastin A and mycophenolic acid in P. roqueforti. The three metabolites were drastically reduced in the pcz1 down-regulated strains. However, when pcz1 was overexpressed, only mycophenolic acid was overproduced while, on the contrary, levels of roquefortine C and andrastin A were diminished. Importantly, these results match the expression pattern of keywords genes involved in the biosynthesis of these metabolites. Taken together, our results suggest that Pcz1 plays a keywords role in regulating secondary metabolism in the fungus Penicillium roqueforti.}, keywords = {biosynthesis, chrysogenum complex, cross-talk, discovery, expression, gene-cluster, laea, metabolism, mycophenolic-acid, pathway pcz1, penicillium protein, roqueforti, secondary subunit}, pubstate = {published}, tppubtype = {article} } Penicillium roqueforti is used in the production of several kinds of ripened blue-veined cheeses. In addition, this fungus produces interesting secondary metabolites such as roquefortine C, andrastin A and mycophenolic acid. To date, there is scarce information concerning the regulation of the production of these secondary metabolites. Recently, the gene named pcz1 (Penicillium C6 zinc domain protein 1) was described in P. roqueforti, which encodes for a Zn(II)(2)Cys(6) protein that controls growth and developmental processes in this fungus. However, its effect on secondary metabolism is currently unknown. In this work, we have analyzed how the overexpression and down-regulation of pcz1 affect the production of roquefortine C, andrastin A and mycophenolic acid in P. roqueforti. The three metabolites were drastically reduced in the pcz1 down-regulated strains. However, when pcz1 was overexpressed, only mycophenolic acid was overproduced while, on the contrary, levels of roquefortine C and andrastin A were diminished. Importantly, these results match the expression pattern of keywords genes involved in the biosynthesis of these metabolites. Taken together, our results suggest that Pcz1 plays a keywords role in regulating secondary metabolism in the fungus Penicillium roqueforti. |
Noureini, S K; Kheirabadi, M; Masoumi, F; Khosrogerdi, F; Zarei, Y; Suarez-Rozas, C; Salas-Norambuena, J; Cassels, B K Telomerase Inhibition by a New Synthetic Derivative of the Aporphine Alkaloid Boldine Artículo de revista International Journal of Molecular Sciences, 19 (4), 2018, ISSN: 1422-0067. Resumen | Enlaces | BibTeX | Etiquetas: apoptosis, assay binding boldine, cells, derivative, domain, inhibition, n-benzylsecoboldine, site, stress, telomerase @article{RN387, title = {Telomerase Inhibition by a New Synthetic Derivative of the Aporphine Alkaloid Boldine}, author = { S.K. Noureini and M. Kheirabadi and F. Masoumi and F. Khosrogerdi and Y. Zarei and C. Suarez-Rozas and J. Salas-Norambuena and B.K. Cassels}, url = {/brokenurl#<Go to ISI>://WOS:000434978700318}, doi = {10.3390/ijms19041239}, issn = {1422-0067}, year = {2018}, date = {2018-01-01}, journal = {International Journal of Molecular Sciences}, volume = {19}, number = {4}, abstract = {Telomerase, the enzyme responsible for cell immortality, is an important target in anti-cancer drug discovery. Boldine, an abundant aporphine alkaloid of Peumus boldus, is known to inhibit telomerase at non-toxic concentrations. Cytotoxicity of N-benzylsecoboldine hydrochloride (BSB), a synthetic derivative of boldine, was determined using the MTT method in MCF7 and MDA-MB231 cells. Aliquots of cell lysates were incubated with various concentrations of BSB in qTRAP (quantitative telomere repeat amplification protocol)-ligand experiments before substrate elongation by telomerase or amplification by hot-start Taq polymerase. The crystal structure of TERT, the catalytic subunit of telomerase from Tribolium castaneum, was used for docking and molecular dynamics analysis. The qTRAP-ligand data gave an IC50 value of about 0.17 +/- 0.1 mu M for BSB, roughly 400 times stronger than boldine, while the LD50 in the cytotoxicity assays were 12.5 and 21.88 mu M, respectively, in cells treated for 48 h. Although both compounds interacted well with the active site, MD analysis suggests a second binding site with which BSB interacts via two hydrogen bonds, much more strongly than boldine. Theoretical analyses also evaluated the IC50 for BSB as submicromolar. BSB, with greater hydrophobicity and flexibility than boldine, represents a promising structure to inhibit telomerase at non-toxic concentrations.}, keywords = {apoptosis, assay binding boldine, cells, derivative, domain, inhibition, n-benzylsecoboldine, site, stress, telomerase}, pubstate = {published}, tppubtype = {article} } Telomerase, the enzyme responsible for cell immortality, is an important target in anti-cancer drug discovery. Boldine, an abundant aporphine alkaloid of Peumus boldus, is known to inhibit telomerase at non-toxic concentrations. Cytotoxicity of N-benzylsecoboldine hydrochloride (BSB), a synthetic derivative of boldine, was determined using the MTT method in MCF7 and MDA-MB231 cells. Aliquots of cell lysates were incubated with various concentrations of BSB in qTRAP (quantitative telomere repeat amplification protocol)-ligand experiments before substrate elongation by telomerase or amplification by hot-start Taq polymerase. The crystal structure of TERT, the catalytic subunit of telomerase from Tribolium castaneum, was used for docking and molecular dynamics analysis. The qTRAP-ligand data gave an IC50 value of about 0.17 +/- 0.1 mu M for BSB, roughly 400 times stronger than boldine, while the LD50 in the cytotoxicity assays were 12.5 and 21.88 mu M, respectively, in cells treated for 48 h. Although both compounds interacted well with the active site, MD analysis suggests a second binding site with which BSB interacts via two hydrogen bonds, much more strongly than boldine. Theoretical analyses also evaluated the IC50 for BSB as submicromolar. BSB, with greater hydrophobicity and flexibility than boldine, represents a promising structure to inhibit telomerase at non-toxic concentrations. |
Munoz, L; Tamayo, L; Gulppi, M; Rabagliati, F; Flores-Catalán, M; Urzúa, M; Azocar, M; Zagal, J H; Encinas, M V; Zhou, X R; Thompson, G; Paez, M Surface Functionalization of an Aluminum Alloy to Generate an Antibiofilm Coating Based on Poly(Methyl Methacrylate) and Silver Nanoparticles Artículo de revista Molecules, 23 (11), 2018, ISSN: 1420-3049. Resumen | Enlaces | BibTeX | Etiquetas: aluminum antibacterial antibiofilm, bacterial coating, contact-angle, efficacy, functionalization, methacrylate), methyl-methacrylate, nanocomposites, particles, pmma, xps @article{RN404, title = {Surface Functionalization of an Aluminum Alloy to Generate an Antibiofilm Coating Based on Poly(Methyl Methacrylate) and Silver Nanoparticles}, author = { L. Munoz and L. Tamayo and M. Gulppi and F. Rabagliati and M. Flores-Catal\'{a}n and M. Urz\'{u}a and M. Azocar and J.H. Zagal and M.V. Encinas and X.R. Zhou and G. Thompson and M. Paez}, url = {/brokenurl#<Go to ISI>://WOS:000451641900019}, doi = {10.3390/molecules23112747}, issn = {1420-3049}, year = {2018}, date = {2018-01-01}, journal = {Molecules}, volume = {23}, number = {11}, abstract = {An experimental protocol was studied to improve the adhesion of a polymeric poly(methyl methacrylate) coating that was modified with silver nanoparticles to an aluminum alloy, AA2024. The nanoparticles were incorporated into the polymeric matrix to add the property of inhibiting biofilm formation to the anticorrosive characteristics of the film, thus also making the coating antibiocorrosive. The protocol consists of functionalizing the surface through a pseudotransesterification treatment using a methyl methacrylate monomer that bonds covalently to the surface and leaves a terminal double bond that promotes and directs the polymerization reaction that takes place in the process that follows immediately after. This results in more compact and thicker poly(methyl methacrylate) (PMMA) coatings than those obtained without pseudotransesterification. The poly(methyl methacrylate) matrix modified with nanoparticles was obtained by incorporating both the nanoparticles and the methyl methacrylate in the reactor. The in situ polymerization involved combining the pretreated AA2024 specimens combined with the methyl methacrylate monomer and AgNps. The antibiofilm capacity of the coating was evaluated against P. aeruginosa, with an excellent response. Not only did the presence of bacteria decrease, but the formation of the exopolymer subunits was 99.99% lower than on the uncoated aluminum alloy or the alloy coated with unmodified poly(methyl methacrylate). As well and significantly, the potentiodynamic polarization measurements indicate that the PMMA-Ag coating has a good anticorrosive property in a 0.1-M NaCl medium.}, keywords = {aluminum antibacterial antibiofilm, bacterial coating, contact-angle, efficacy, functionalization, methacrylate), methyl-methacrylate, nanocomposites, particles, pmma, xps}, pubstate = {published}, tppubtype = {article} } An experimental protocol was studied to improve the adhesion of a polymeric poly(methyl methacrylate) coating that was modified with silver nanoparticles to an aluminum alloy, AA2024. The nanoparticles were incorporated into the polymeric matrix to add the property of inhibiting biofilm formation to the anticorrosive characteristics of the film, thus also making the coating antibiocorrosive. The protocol consists of functionalizing the surface through a pseudotransesterification treatment using a methyl methacrylate monomer that bonds covalently to the surface and leaves a terminal double bond that promotes and directs the polymerization reaction that takes place in the process that follows immediately after. This results in more compact and thicker poly(methyl methacrylate) (PMMA) coatings than those obtained without pseudotransesterification. The poly(methyl methacrylate) matrix modified with nanoparticles was obtained by incorporating both the nanoparticles and the methyl methacrylate in the reactor. The in situ polymerization involved combining the pretreated AA2024 specimens combined with the methyl methacrylate monomer and AgNps. The antibiofilm capacity of the coating was evaluated against P. aeruginosa, with an excellent response. Not only did the presence of bacteria decrease, but the formation of the exopolymer subunits was 99.99% lower than on the uncoated aluminum alloy or the alloy coated with unmodified poly(methyl methacrylate). As well and significantly, the potentiodynamic polarization measurements indicate that the PMMA-Ag coating has a good anticorrosive property in a 0.1-M NaCl medium. |
Gomez-Jeria, J S; Clavijo, E; Gutierrez, S A Qualitative Infrared and Scanning Electron Microscopy Study of the Margins of Fourteen World Postage Stamps Artículo de revista Research Journal of Pharmaceutical Biological and Chemical Sciences, 9 (6), pp. 1719-+, 2018, ISSN: 0975-8585. Resumen | Enlaces | BibTeX | Etiquetas: archeology, cellulose, electron ft-ir infrared kaolinite, microscopy, paper philately, pigments, postage raman scanning sem, spectra, spectroscopy, stamps, xrf @article{RN415, title = {A Qualitative Infrared and Scanning Electron Microscopy Study of the Margins of Fourteen World Postage Stamps}, author = { J.S. Gomez-Jeria and E. Clavijo and S. Gutierrez}, url = {/brokenurl#<Go to ISI>://WOS:000449630700274}, issn = {0975-8585}, year = {2018}, date = {2018-01-01}, journal = {Research Journal of Pharmaceutical Biological and Chemical Sciences}, volume = {9}, number = {6}, pages = {1719-+}, abstract = {Fourteen heavily damaged postage stamps were chosen for an infrared and scanning electron microscopy (SEM) characterization of their non-printed margins. The results show the presence of kaolinite used as filler in all but two samples. These last two contain aluminum (with an Al-OH moiety). One stamp seems to contain barium in the form of sulfate. One stamp contains lead in an unknown chemical compound. All these results were incorporated into a database for future analysis. Quantum chemical calculations of diverse large models of cellulose seem absolutely necessary for the IR band assignments.}, keywords = {archeology, cellulose, electron ft-ir infrared kaolinite, microscopy, paper philately, pigments, postage raman scanning sem, spectra, spectroscopy, stamps, xrf}, pubstate = {published}, tppubtype = {article} } Fourteen heavily damaged postage stamps were chosen for an infrared and scanning electron microscopy (SEM) characterization of their non-printed margins. The results show the presence of kaolinite used as filler in all but two samples. These last two contain aluminum (with an Al-OH moiety). One stamp seems to contain barium in the form of sulfate. One stamp contains lead in an unknown chemical compound. All these results were incorporated into a database for future analysis. Quantum chemical calculations of diverse large models of cellulose seem absolutely necessary for the IR band assignments. |
Herrera-Marschitz, M; Perez-Lobos, R; Lespay-Rebolledo, C; Tapia-Bustos, A; Casanova-Ortiz, E; Morales, P; Valdes, J L; Bustamante, D; Cassels, B K Targeting Sentinel Proteins and Extrasynaptic Glutamate Receptors: A Therapeutic Strategy for Preventing the Effects Elicited by Perinatal Asphyxia? Artículo de revista Neurotoxicity Research, 33 (2), pp. 461-473, 2018, ISSN: 1029-8428. Resumen | Enlaces | BibTeX | Etiquetas: basal brain-damage, cell cell-death, cultures, death, delayed encephalopathy encephalopathy, factor-i, ganglia, gfap, hypoxia, hypoxic hypoxic-ischemic inducible ischaemic leukomalacia, map-2, memantine, n-acetylcysteine neonatal niacinamide, nitric-oxide nmda nnos, organotypic oxidative rat rat, receptors, stress, substantia-nigra, synthase, tunel @article{RN385, title = {Targeting Sentinel Proteins and Extrasynaptic Glutamate Receptors: A Therapeutic Strategy for Preventing the Effects Elicited by Perinatal Asphyxia?}, author = { M. Herrera-Marschitz and R. Perez-Lobos and C. Lespay-Rebolledo and A. Tapia-Bustos and E. Casanova-Ortiz and P. Morales and J.L. Valdes and D. Bustamante and B.K. Cassels}, url = {/brokenurl#<Go to ISI>://WOS:000422640700020}, doi = {10.1007/s12640-017-9795-9}, issn = {1029-8428}, year = {2018}, date = {2018-01-01}, journal = {Neurotoxicity Research}, volume = {33}, number = {2}, pages = {461-473}, abstract = {Perinatal asphyxia (PA) is a relevant cause of death at the time of labour, and when survival is stabilised, associated with short- and long-term developmental disabilities, requiring inordinate care by health systems and families. Its prevalence is high (1 to 10/1000 live births) worldwide. At present, there are few therapeutic options, apart from hypothermia, that regrettably provides only limited protection if applied shortly after the insult., PA implies a primary and a secondary insult. The primary insult relates to the lack of oxygen, and the secondary one to the oxidative stress triggered by re-oxygenation, formation of reactive oxygen (ROS) and reactive nitrogen (RNS) species, and overactivation of glutamate receptors and mitochondrial deficiencies. PA induces overactivation of a number of sentinel proteins, including hypoxia-induced factor-1 alpha (HIF-1 alpha) and the genome-protecting poly(ADP-ribose) polymerase-1 (PARP-1). Upon activation, PARP-1 consumes high amounts of ATP at a time when this metabolite is scarce, worsening in turn the energy crisis elicited by asphyxia. The energy crisis also impairs ATP-dependent transport, including glutamate re-uptake by astroglia. Nicotinamide, a PARP-1 inhibitor, protects against the metabolic cascade elicited by the primary stage, avoiding NAD(+) exhaustion and the energetic crisis. Upon re-oxygenation, however, oxidative stress leads to nuclear translocation of the NF-kappa B subunit p65, overexpression of the pro-inflammatory cytokines IL-1 beta and TNF-alpha, and glutamate-excitotoxicity, due to impairment of glial-glutamate transport, extracellular glutamate overflow, and overactivation of NMDA receptors, mainly of the extrasynaptic type. This leads to calcium influx, mitochondrial impairment, and inactivation of antioxidant enzymes, increasing further the activity of pro-oxidant enzymes, thereby making the surviving neonate vulnerable to recurrent metabolic insults whenever oxidative stress is involved. Here, we discuss evidence showing that (i) inhibition of PARP-1 overactivation by nicotinamide and (ii) inhibition of extrasynaptic NMDA receptor overactivation by memantine can prevent the short- and long-term consequences of PA. These hypotheses have been evaluated in a rat preclinical model of PA, aiming to identify the metabolic cascades responsible for the long-term consequences induced by the insult, also assessing postnatal vulnerability to recurrent oxidative insults. Thus, we present and discuss evidence demonstrating that PA induces long-term changes in metabolic pathways related to energy and oxidative stress, priming vulnerability of cells with both the neuronal and the glial phenotype. The effects induced by PA are region dependent, the substantia nigra being particularly prone to cell death. The issue of short- and long-term consequences of PA provides a framework for addressing a fundamental issue referred to plasticity of the CNS, since the perinatal insult triggers a domino-like sequence of events making the developing individual vulnerable to recurrent adverse conditions, decreasing his/her coping repertoire because of a relevant insult occurring at birth.}, keywords = {basal brain-damage, cell cell-death, cultures, death, delayed encephalopathy encephalopathy, factor-i, ganglia, gfap, hypoxia, hypoxic hypoxic-ischemic inducible ischaemic leukomalacia, map-2, memantine, n-acetylcysteine neonatal niacinamide, nitric-oxide nmda nnos, organotypic oxidative rat rat, receptors, stress, substantia-nigra, synthase, tunel}, pubstate = {published}, tppubtype = {article} } Perinatal asphyxia (PA) is a relevant cause of death at the time of labour, and when survival is stabilised, associated with short- and long-term developmental disabilities, requiring inordinate care by health systems and families. Its prevalence is high (1 to 10/1000 live births) worldwide. At present, there are few therapeutic options, apart from hypothermia, that regrettably provides only limited protection if applied shortly after the insult., PA implies a primary and a secondary insult. The primary insult relates to the lack of oxygen, and the secondary one to the oxidative stress triggered by re-oxygenation, formation of reactive oxygen (ROS) and reactive nitrogen (RNS) species, and overactivation of glutamate receptors and mitochondrial deficiencies. PA induces overactivation of a number of sentinel proteins, including hypoxia-induced factor-1 alpha (HIF-1 alpha) and the genome-protecting poly(ADP-ribose) polymerase-1 (PARP-1). Upon activation, PARP-1 consumes high amounts of ATP at a time when this metabolite is scarce, worsening in turn the energy crisis elicited by asphyxia. The energy crisis also impairs ATP-dependent transport, including glutamate re-uptake by astroglia. Nicotinamide, a PARP-1 inhibitor, protects against the metabolic cascade elicited by the primary stage, avoiding NAD(+) exhaustion and the energetic crisis. Upon re-oxygenation, however, oxidative stress leads to nuclear translocation of the NF-kappa B subunit p65, overexpression of the pro-inflammatory cytokines IL-1 beta and TNF-alpha, and glutamate-excitotoxicity, due to impairment of glial-glutamate transport, extracellular glutamate overflow, and overactivation of NMDA receptors, mainly of the extrasynaptic type. This leads to calcium influx, mitochondrial impairment, and inactivation of antioxidant enzymes, increasing further the activity of pro-oxidant enzymes, thereby making the surviving neonate vulnerable to recurrent metabolic insults whenever oxidative stress is involved. Here, we discuss evidence showing that (i) inhibition of PARP-1 overactivation by nicotinamide and (ii) inhibition of extrasynaptic NMDA receptor overactivation by memantine can prevent the short- and long-term consequences of PA. These hypotheses have been evaluated in a rat preclinical model of PA, aiming to identify the metabolic cascades responsible for the long-term consequences induced by the insult, also assessing postnatal vulnerability to recurrent oxidative insults. Thus, we present and discuss evidence demonstrating that PA induces long-term changes in metabolic pathways related to energy and oxidative stress, priming vulnerability of cells with both the neuronal and the glial phenotype. The effects induced by PA are region dependent, the substantia nigra being particularly prone to cell death. The issue of short- and long-term consequences of PA provides a framework for addressing a fundamental issue referred to plasticity of the CNS, since the perinatal insult triggers a domino-like sequence of events making the developing individual vulnerable to recurrent adverse conditions, decreasing his/her coping repertoire because of a relevant insult occurring at birth. |
Vilches-Herrera, M; Concha-Puelles, M; Carvajal, N; Molina, J; Santander, R; Rezende, M C; Luhr, S Influence of the Bite Natural Angle of Bidentate Diphosphine Ligands in the Syngas-Free Branched Hydroformylation of Beta-Functionalized Olefins Artículo de revista Catalysis Communications, 116 , pp. 62-66, 2018, ISSN: 1566-7367. Resumen | Enlaces | BibTeX | Etiquetas: allyl angles, asymmetric beta-functionalized bite cyanide, diphosphine formaldehyde hydroformylation, hydrogenations, ligands, natural olefins, p-op regioselectivity, rhodium-catalyzed syngas-free @article{RN391, title = {Influence of the Bite Natural Angle of Bidentate Diphosphine Ligands in the Syngas-Free Branched Hydroformylation of Beta-Functionalized Olefins}, author = { M. Vilches-Herrera and M. Concha-Puelles and N. Carvajal and J. Molina and R. Santander and M.C. Rezende and S. Luhr}, url = {/brokenurl#<Go to ISI>://WOS:000444933100013}, doi = {10.1016/j.catcom.2018.08.007}, issn = {1566-7367}, year = {2018}, date = {2018-01-01}, journal = {Catalysis Communications}, volume = {116}, pages = {62-66}, abstract = {The correlation between the activity, regio- and chemoselectivity of Rh-diphosphine catalyst and the ligand bite natural angle (beta(n)) in the syngas-free hydroformylation of allyl cyanide was investigated. A screening of Xantphos type and diphosphine alkyl ligands with different bite natural angles was studied. Interesting, a switch in the linear to the branch regioselectivity was found. Wide beta(n) favour a linear regioselectivity whereas smaller beta(n) allow the formation of the branched aldehyde as the major product. Modification of the substituents at the phosphorus atoms of the diphosphine ligands produced a dramatic change in the hydroformylation. Others beta-functionalized olefins were also branched hydroformylated.}, keywords = {allyl angles, asymmetric beta-functionalized bite cyanide, diphosphine formaldehyde hydroformylation, hydrogenations, ligands, natural olefins, p-op regioselectivity, rhodium-catalyzed syngas-free}, pubstate = {published}, tppubtype = {article} } The correlation between the activity, regio- and chemoselectivity of Rh-diphosphine catalyst and the ligand bite natural angle (beta(n)) in the syngas-free hydroformylation of allyl cyanide was investigated. A screening of Xantphos type and diphosphine alkyl ligands with different bite natural angles was studied. Interesting, a switch in the linear to the branch regioselectivity was found. Wide beta(n) favour a linear regioselectivity whereas smaller beta(n) allow the formation of the branched aldehyde as the major product. Modification of the substituents at the phosphorus atoms of the diphosphine ligands produced a dramatic change in the hydroformylation. Others beta-functionalized olefins were also branched hydroformylated. |
Dreyse, P; Alarcon, D A; Galdámez, A; González, I; Cortes-Arriagada, D; Castillo, F; Mella, A Influence of the Anion Nature and Alkyl Substituents in the Behavior of Ionic Liquids Derived from Phenylpyridines Artículo de revista Journal of Molecular Structure, 1154 , pp. 382-391, 2018, ISSN: 0022-2860. Resumen | Enlaces | BibTeX | Etiquetas: binding compounds, crystal design electrochemical-cells, emitting energies, gold ion ionic liquids, nanoparticles, pairs phenylpyridiniums, salts, solvents, structure, temperature, transition, transport, water @article{RN402, title = {Influence of the Anion Nature and Alkyl Substituents in the Behavior of Ionic Liquids Derived from Phenylpyridines}, author = { P. Dreyse and D.A. Alarcon and A. Gald\'{a}mez and I. Gonz\'{a}lez and D. Cortes-Arriagada and F. Castillo and A. Mella}, url = {/brokenurl#<Go to ISI>://WOS:000418212000043}, doi = {10.1016/j.molstruc.2017.10.062}, issn = {0022-2860}, year = {2018}, date = {2018-01-01}, journal = {Journal of Molecular Structure}, volume = {1154}, pages = {382-391}, publisher = {2017 Elsevier B.V.}, abstract = {Quaternary alkyl 2-phenylpyridinium and 2-(2,4-difluorophenyl)pyridinium amines with iodide, hexafluorophosphate and bis(trifluoromethylsulfonyl)imide anions have been fully characterized by H-1 NMR, FT-IR and MALDI mass spectroscopic methods and studied by quantum chemistry calculations. The compounds with bis(trifluoromethylsulfonyl)imide anion can be classified as ionic liquids, because they melt at room temperature. The quaternary amines with iodide and hexafluorophosphate anions are solid at 25 degrees C. The X-ray diffraction characterization of the 2-(2,4-difiuorophenyl)-1-methylphenylpyridinium hexafluorophosphate and 1-ethyl-2-(2,4-difluorophenyl)phenylpyridinium hexafluorophosphate show an extensive series of C-H center dot center dot center dot F, C-F center dot center dot center dot pi and P-F center dot center dot center dot pi it intermolecular interactions, which give rise to a supramolecular network. The relationship between the solid-state structures and the melting points is discussed by the evaluation of the thermal behavior based on experimental data from Differential Scanning Calorimetry (DSC) studies, and also using the analysis of the ion pairs binding energies. These new compounds based on phenylpyridine allow us to grow the diversity of ionic liquids and their crystalline salts, increasing the knowledge about the chemical and physical properties of these ionic species.}, keywords = {binding compounds, crystal design electrochemical-cells, emitting energies, gold ion ionic liquids, nanoparticles, pairs phenylpyridiniums, salts, solvents, structure, temperature, transition, transport, water}, pubstate = {published}, tppubtype = {article} } Quaternary alkyl 2-phenylpyridinium and 2-(2,4-difluorophenyl)pyridinium amines with iodide, hexafluorophosphate and bis(trifluoromethylsulfonyl)imide anions have been fully characterized by H-1 NMR, FT-IR and MALDI mass spectroscopic methods and studied by quantum chemistry calculations. The compounds with bis(trifluoromethylsulfonyl)imide anion can be classified as ionic liquids, because they melt at room temperature. The quaternary amines with iodide and hexafluorophosphate anions are solid at 25 degrees C. The X-ray diffraction characterization of the 2-(2,4-difiuorophenyl)-1-methylphenylpyridinium hexafluorophosphate and 1-ethyl-2-(2,4-difluorophenyl)phenylpyridinium hexafluorophosphate show an extensive series of C-H center dot center dot center dot F, C-F center dot center dot center dot pi and P-F center dot center dot center dot pi it intermolecular interactions, which give rise to a supramolecular network. The relationship between the solid-state structures and the melting points is discussed by the evaluation of the thermal behavior based on experimental data from Differential Scanning Calorimetry (DSC) studies, and also using the analysis of the ion pairs binding energies. These new compounds based on phenylpyridine allow us to grow the diversity of ionic liquids and their crystalline salts, increasing the knowledge about the chemical and physical properties of these ionic species. |
Villalobos, V; Leiva, A; Rios, H; Pavez, J; Silva, C P; Ahmar, M; Queneau, Y; Blamey, J M; Chavez, F P; Urzúa, M Inhibiting Pathogen Surface Adherence by Multilayer Polyelectrolyte Films Functionalized with Glucofuranose Derivatives Artículo de revista Acs Applied Materials & Interfaces, 10 (33), pp. 28147-28158, 2018, ISSN: 1944-8244. Resumen | Enlaces | BibTeX | Etiquetas: antibacterial bacterial, biofilm biomaterials, carbohydrate challenges coatings, construction, formation, inhibition, mechanisms, p. polyelectrolytes, resistance, s. surfaces, typhimurium @article{RN403, title = {Inhibiting Pathogen Surface Adherence by Multilayer Polyelectrolyte Films Functionalized with Glucofuranose Derivatives}, author = { V. Villalobos and A. Leiva and H. Rios and J. Pavez and C.P. Silva and M. Ahmar and Y. Queneau and J.M. Blamey and F.P. Chavez and M. Urz\'{u}a}, url = {/brokenurl#<Go to ISI>://WOS:000442706600064}, doi = {10.1021/acsami.8b03605}, issn = {1944-8244}, year = {2018}, date = {2018-01-01}, journal = {Acs Applied Materials & Interfaces}, volume = {10}, number = {33}, pages = {28147-28158}, abstract = {Inhibiting pathogenic bacterial adherence on surfaces is an ongoing challenge to prevent the development of biofilms. Multilayer polyelectrolyte films are feasible antibacterial materials. Here, we have designed new films made of carbohydrate polyelectrolytes to obtain antibacterial coatings that prevent biofilm formation. The polyelectrolyte films were constructed from poly(maleic anhydride-alt-styrene) functionalized with glucofuranose derivatives and quaternized poly(4-vinylpyridine) N-alkyl. These films prevent Pseudomonas aeruginosa and Salmonella Typhimurium, two important bacterial contaminants in clinical environments, from adhering to surfaces. When the film was composed of more than 10 layers, the bacterial population was greatly reduced, while the bacteria remaining on the film were morphologically damaged, as atomic force microscopy revealed. The antibacterial capacity of the polyelectrolyte films was determined by the combination of thickness, wettability, surface energy, and most importantly, the conformation that polyelectrolytes adopt the function of nature of the carbohydrate group. This polyelectrolyte film constitutes the first green approach to preventing pathogenic bacterial surface adherence and proliferation without killing the bacterial pathogen.}, keywords = {antibacterial bacterial, biofilm biomaterials, carbohydrate challenges coatings, construction, formation, inhibition, mechanisms, p. polyelectrolytes, resistance, s. surfaces, typhimurium}, pubstate = {published}, tppubtype = {article} } Inhibiting pathogenic bacterial adherence on surfaces is an ongoing challenge to prevent the development of biofilms. Multilayer polyelectrolyte films are feasible antibacterial materials. Here, we have designed new films made of carbohydrate polyelectrolytes to obtain antibacterial coatings that prevent biofilm formation. The polyelectrolyte films were constructed from poly(maleic anhydride-alt-styrene) functionalized with glucofuranose derivatives and quaternized poly(4-vinylpyridine) N-alkyl. These films prevent Pseudomonas aeruginosa and Salmonella Typhimurium, two important bacterial contaminants in clinical environments, from adhering to surfaces. When the film was composed of more than 10 layers, the bacterial population was greatly reduced, while the bacteria remaining on the film were morphologically damaged, as atomic force microscopy revealed. The antibacterial capacity of the polyelectrolyte films was determined by the combination of thickness, wettability, surface energy, and most importantly, the conformation that polyelectrolytes adopt the function of nature of the carbohydrate group. This polyelectrolyte film constitutes the first green approach to preventing pathogenic bacterial surface adherence and proliferation without killing the bacterial pathogen. |
Pinto, C; Lopez, F; Galdámez, A; Barahona, P; Moris, S Vibrational and Optical Properties of Czts Derivatives for Photovoltaic Applications: Synthesis of Cu2znsn1-Xgexs2se2 Compounds Artículo de revista Solid State Sciences, 85 , pp. 76-82, 2018, ISSN: 1293-2558. Resumen | Enlaces | BibTeX | Etiquetas: analysis, band-gap, cu2znsns4, czts, method, nanocrystals, nanoparticles, raman raman-scattering scattering, single-crystals, solar-cells, spectroscopy spray-pyrolysis @article{RN399, title = {Vibrational and Optical Properties of Czts Derivatives for Photovoltaic Applications: Synthesis of Cu2znsn1-Xgexs2se2 Compounds}, author = { C. Pinto and F. Lopez and A. Gald\'{a}mez and P. Barahona and S. Moris}, url = {/brokenurl#<Go to ISI>://WOS:000448954400011}, doi = {10.1016/j.solidstatesciences.2018.09.005}, issn = {1293-2558}, year = {2018}, date = {2018-01-01}, journal = {Solid State Sciences}, volume = {85}, pages = {76-82}, abstract = {Herein, we report the vibrational and optical properties of new Cu2ZnSn1-xGexS2Se2 solid solutions prepared by isomorphic substitution of a fraction of Se by S in Cu2ZnSn1-xGexSe4 (CZTGeSe) through ceramic method. The Raman spectra and x-ray diffraction analysis on samples confirms that they crystallize in Kesterite-type structure. The Raman peaks were analyzed by fitting of the spectra allowing identification the vibrational modes by comparison with experimental and theoretical data from CZTGeSe and CZTGeS end-members. The dependency between the amount of cation and chalcogen substituent in optical characterization shows band gap around of 1.36 eV, close to the optimum value for solar cells with high efficiency.}, keywords = {analysis, band-gap, cu2znsns4, czts, method, nanocrystals, nanoparticles, raman raman-scattering scattering, single-crystals, solar-cells, spectroscopy spray-pyrolysis}, pubstate = {published}, tppubtype = {article} } Herein, we report the vibrational and optical properties of new Cu2ZnSn1-xGexS2Se2 solid solutions prepared by isomorphic substitution of a fraction of Se by S in Cu2ZnSn1-xGexSe4 (CZTGeSe) through ceramic method. The Raman spectra and x-ray diffraction analysis on samples confirms that they crystallize in Kesterite-type structure. The Raman peaks were analyzed by fitting of the spectra allowing identification the vibrational modes by comparison with experimental and theoretical data from CZTGeSe and CZTGeS end-members. The dependency between the amount of cation and chalcogen substituent in optical characterization shows band gap around of 1.36 eV, close to the optimum value for solar cells with high efficiency. |
Sanchez, B; Calderon, C; Tapia, R A; Contreras, R; Campodonico, P R Activation of Electrophile/Nucleophile Pair by a Nucleophilic and Electrophilic Solvation in a Snar Reaction Artículo de revista Frontiers in Chemistry, 6 , 2018, ISSN: 2296-2646. Resumen | Enlaces | BibTeX | Etiquetas: anion aromatic-substitution catalysis, effect, effects, electronic ionic liquids, mixtures, organic-reactions, potentials preferential reactions, secondary-amines, solvation, solvent solvent, temperature theory @article{RN420, title = {Activation of Electrophile/Nucleophile Pair by a Nucleophilic and Electrophilic Solvation in a Snar Reaction}, author = { B. Sanchez and C. Calderon and R.A. Tapia and R. Contreras and P.R. Campodonico}, url = {/brokenurl#<Go to ISI>://WOS:000447985400001}, doi = {10.3389/fchem.2018.00509}, issn = {2296-2646}, year = {2018}, date = {2018-01-01}, journal = {Frontiers in Chemistry}, volume = {6}, abstract = {Nucleophilic aromatic substitution reactions of 4-chloroquinazoline toward aniline and hydrazine were used as a model system to experimentally show that a substrate bearing heteroatoms on the aromatic ring as substituent is able to establish intramolecular hydrogen bond which may be activated by the reaction media and/or the nature of the nucleophile.}, keywords = {anion aromatic-substitution catalysis, effect, effects, electronic ionic liquids, mixtures, organic-reactions, potentials preferential reactions, secondary-amines, solvation, solvent solvent, temperature theory}, pubstate = {published}, tppubtype = {article} } Nucleophilic aromatic substitution reactions of 4-chloroquinazoline toward aniline and hydrazine were used as a model system to experimentally show that a substrate bearing heteroatoms on the aromatic ring as substituent is able to establish intramolecular hydrogen bond which may be activated by the reaction media and/or the nature of the nucleophile. |
Poveda, G; Gil-Duran, C; Vaca, I; Levican, G; Chavez, R Cold-Active Pectinolytic Activity Produced by Filamentous Fungi Associated with Antarctic Marine Sponges Artículo de revista Biological Research, 51 , 2018, ISSN: 0716-9760. Resumen | Enlaces | BibTeX | Etiquetas: antarctic cold-active diversity, enzymes, filamentous fungi, geomyces geomyces, marine pectinases, polygalacturonase, purification, sp., sponges, strains yeasts @article{RN384, title = {Cold-Active Pectinolytic Activity Produced by Filamentous Fungi Associated with Antarctic Marine Sponges}, author = { G. Poveda and C. Gil-Duran and I. Vaca and G. Levican and R. Chavez}, url = {/brokenurl#<Go to ISI>://WOS:000442838400001}, doi = {10.1186/s40659-018-0177-4}, issn = {0716-9760}, year = {2018}, date = {2018-01-01}, journal = {Biological Research}, volume = {51}, abstract = {Background: Pectinase enzymes catalyze the breakdown of pectin, a keywords component of the plant cell wall. At industrial level, pectinases are used in diverse applications, especially in food-processing industry. Currently, most of the industrial pectinases have optimal activity at mesophilic temperatures. On the contrary, very little is known about the pectinolytic activities from organisms from cold climates such as Antarctica. In this work, 27 filamentous fungi isolated from marine sponges collected in King George Island, Antarctica, were screened as new source of cold-active pectinases., Results: In semi-quantitative plate assays, 8 out 27 of these isolates showed pectinolytic activities at 15 degrees C and one of them, Geomyces sp. strain F09-T3-2, showed the highest production of pectinases in liquid medium containing pectin as sole carbon source. More interesting, Geomyces sp. F09-T3-2 showed optimal pectinolytic activity at 30 degrees C, 10 degrees C under the temperature of currently available commercial mesophilic pectinases., Conclusion: Filamentous fungi associated with Antarctic marine sponges are a promising source of pectinolytic activity. In particular, pectinases from Geomyces sp. F09-T3-2 may be potentially suitable for biotechnological applications needing cold-active pectinases. To the best of our knowledge, this is the first report describing the production of pectinolytic activity from filamentous fungi from any environment in Antarctica.}, keywords = {antarctic cold-active diversity, enzymes, filamentous fungi, geomyces geomyces, marine pectinases, polygalacturonase, purification, sp., sponges, strains yeasts}, pubstate = {published}, tppubtype = {article} } Background: Pectinase enzymes catalyze the breakdown of pectin, a keywords component of the plant cell wall. At industrial level, pectinases are used in diverse applications, especially in food-processing industry. Currently, most of the industrial pectinases have optimal activity at mesophilic temperatures. On the contrary, very little is known about the pectinolytic activities from organisms from cold climates such as Antarctica. In this work, 27 filamentous fungi isolated from marine sponges collected in King George Island, Antarctica, were screened as new source of cold-active pectinases., Results: In semi-quantitative plate assays, 8 out 27 of these isolates showed pectinolytic activities at 15 degrees C and one of them, Geomyces sp. strain F09-T3-2, showed the highest production of pectinases in liquid medium containing pectin as sole carbon source. More interesting, Geomyces sp. F09-T3-2 showed optimal pectinolytic activity at 30 degrees C, 10 degrees C under the temperature of currently available commercial mesophilic pectinases., Conclusion: Filamentous fungi associated with Antarctic marine sponges are a promising source of pectinolytic activity. In particular, pectinases from Geomyces sp. F09-T3-2 may be potentially suitable for biotechnological applications needing cold-active pectinases. To the best of our knowledge, this is the first report describing the production of pectinolytic activity from filamentous fungi from any environment in Antarctica. |
Rubio, S; Noriega, X; Pérez, F J Abscisic Acid (Aba) and Low Temperatures Synergistically Increase the Expression of Cbf/Dreb1 Transcription Factors and Cold-Hardiness in Grapevine Dormant Buds Artículo de revista Annals of Botany, 123 (4), pp. 681-689, 2018, ISSN: 0305-7364. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN65, title = {Abscisic Acid (Aba) and Low Temperatures Synergistically Increase the Expression of Cbf/Dreb1 Transcription Factors and Cold-Hardiness in Grapevine Dormant Buds}, author = {S Rubio and X Noriega and F J P\'{e}rez}, url = {https://doi.org/10.1093/aob/mcy201}, doi = {10.1093/aob/mcy201}, issn = {0305-7364}, year = {2018}, date = {2018-01-01}, journal = {Annals of Botany}, volume = {123}, number = {4}, pages = {681-689}, publisher = {2012 Elsevier Ltd.}, abstract = {It has been reported that low temperatures (LTs) and the plant hormone abscisic acid (ABA) induce the expression of CBF/DREB1 transcription factors in vegetative tissues and seedlings of Vitis vinifera and Vitis riparia and that foliar applications of ABA to V. vinifera increase the freezing tolerance or cold-hardiness of dormant buds. However, the combined effect of ABA and LTs on the expression of CBF/DREB1 transcription factors and on the acquisition of freezing tolerance in dormant grapevine buds has not been investigated. The objective of this study was to analyse the combined effect of ABA and LT treatments on the expression of CBF/DREB transcription factors and the acquisition of freezing tolerance.In vitro experiments with single-bud cuttings of grapevines were used to analyse the effect of ABA, ABA + LT and LT on the expression of CBF/DREB transcription factors, dehydrin and antioxidant genes, the acquisition of freezing tolerance and the endogenous content of ABA. Gene expression analysis was performed by quantitative real-time PCR and freezing tolerance was determined by measuring the low-temperature exotherm by differential thermal analysis. ABA levels were determined by gas chromatography coupled to an electron capture detector.The LT treatment and exogenous application of ABA to grapevine dormant buds increased the expression of the CBF/DREB1 transcription factors VvCBF2, VvCBF3, VvCBF4 and VvCBF6. The joint application of LT and ABA produced a huge increase in the expression of these transcription factors, which was greater than the sum of the increases produced by them individually, which indicates the existence of a synergistic effect between ABA and LT on the activation of these transcription factors. This synergic effect was also observed on the increase in bud cold-hardiness and on the expression of antioxidant and dehydrin genes.The synergy between ABA and LT on the expression of CBF/DREB1 transcription factors VvCBF2, VvCBF3, VvCBF4 and VvCBF6 plays a key role in cold acclimatization of grapevine buds. The results highlight the importance of the combination of stimuli in the improvement of genetic and physiological responses and help us to understand the adaption of plants to complex environments.}, keywords = {}, pubstate = {published}, tppubtype = {article} } It has been reported that low temperatures (LTs) and the plant hormone abscisic acid (ABA) induce the expression of CBF/DREB1 transcription factors in vegetative tissues and seedlings of Vitis vinifera and Vitis riparia and that foliar applications of ABA to V. vinifera increase the freezing tolerance or cold-hardiness of dormant buds. However, the combined effect of ABA and LTs on the expression of CBF/DREB1 transcription factors and on the acquisition of freezing tolerance in dormant grapevine buds has not been investigated. The objective of this study was to analyse the combined effect of ABA and LT treatments on the expression of CBF/DREB transcription factors and the acquisition of freezing tolerance.In vitro experiments with single-bud cuttings of grapevines were used to analyse the effect of ABA, ABA + LT and LT on the expression of CBF/DREB transcription factors, dehydrin and antioxidant genes, the acquisition of freezing tolerance and the endogenous content of ABA. Gene expression analysis was performed by quantitative real-time PCR and freezing tolerance was determined by measuring the low-temperature exotherm by differential thermal analysis. ABA levels were determined by gas chromatography coupled to an electron capture detector.The LT treatment and exogenous application of ABA to grapevine dormant buds increased the expression of the CBF/DREB1 transcription factors VvCBF2, VvCBF3, VvCBF4 and VvCBF6. The joint application of LT and ABA produced a huge increase in the expression of these transcription factors, which was greater than the sum of the increases produced by them individually, which indicates the existence of a synergistic effect between ABA and LT on the activation of these transcription factors. This synergic effect was also observed on the increase in bud cold-hardiness and on the expression of antioxidant and dehydrin genes.The synergy between ABA and LT on the expression of CBF/DREB1 transcription factors VvCBF2, VvCBF3, VvCBF4 and VvCBF6 plays a key role in cold acclimatization of grapevine buds. The results highlight the importance of the combination of stimuli in the improvement of genetic and physiological responses and help us to understand the adaption of plants to complex environments. |
Becerra-Ruiz, M; Vargas, V; Jara, P; Tirapegui, C; Carrasco, C; Nunez, M; Lezana, N; Galdámez, A; Vilches-Herrera, M Blue-Fluorescent Probes for Lipid Droplets Based on Dihydrochromeno-Fused Pyrazolo- and Pyrrolopyridines Artículo de revista European Journal of Organic Chemistry, 10.1002/ejoc.201701633 (34), pp. 4795-4801, 2018, ISSN: 1434-193x. Resumen | Enlaces | BibTeX | Etiquetas: derivatives, design, diels-alder dyes, fluorescent fused-ring heterocycles, lipids, nitrogen photophysics, probes, prodrugs, reactions, red solvent, systems @article{RN390, title = {Blue-Fluorescent Probes for Lipid Droplets Based on Dihydrochromeno-Fused Pyrazolo- and Pyrrolopyridines}, author = { M. Becerra-Ruiz and V. Vargas and P. Jara and C. Tirapegui and C. Carrasco and M. Nunez and N. Lezana and A. Gald\'{a}mez and M. Vilches-Herrera}, url = {/brokenurl#<Go to ISI>://WOS:000444540900018}, doi = {10.1002/ejoc.201701633}, issn = {1434-193x}, year = {2018}, date = {2018-01-01}, journal = {European Journal of Organic Chemistry}, volume = {10.1002/ejoc.201701633}, number = {34}, pages = {4795-4801}, abstract = {Lipid droplets (LDs) have been recognized as highly dynamic cellular organelles involved in important biological functions for the survival of organisms such as supplying food or energy. Nevertheless, lipid storage must be tightly controlled, because both its excess and the inability to store lipids can be detrimental to the organism, resulting in metabolic diseases or multifaceted systemic problems. Visualization and the monitoring of the concentration of LDs is essential to understanding these processes. Commercially available LD dyes, such as Nile Red and boron-dipyrromethene (BODIPY), offer several advantageous characteristics, but can be limiting in multicolor imaging because most ready-made fluorescent reporter constructs fluoresce in the green-to-red region of the visible spectrum. Nile Red emits between green and red, and BODIPY can be photoconverted from green to red fluorescence, limiting its ability to be utilized for time-lapse imaging of living cells. Here, we report the design and synthesis, the photophysical characterization, and biological testing of two easily prepared series of new blue-fluorescing dyes as markers for LDs. Confocal fluorescence microscopy results showed an interesting correlation between the chemical structures of these fluorescent probes and their specific staining patterns. The pyrazole-based compound 11c was found to be a specific dye for LDs, whereas the pyrrole-based compound 10d led to prominent staining of the membranous cell organelles.}, keywords = {derivatives, design, diels-alder dyes, fluorescent fused-ring heterocycles, lipids, nitrogen photophysics, probes, prodrugs, reactions, red solvent, systems}, pubstate = {published}, tppubtype = {article} } Lipid droplets (LDs) have been recognized as highly dynamic cellular organelles involved in important biological functions for the survival of organisms such as supplying food or energy. Nevertheless, lipid storage must be tightly controlled, because both its excess and the inability to store lipids can be detrimental to the organism, resulting in metabolic diseases or multifaceted systemic problems. Visualization and the monitoring of the concentration of LDs is essential to understanding these processes. Commercially available LD dyes, such as Nile Red and boron-dipyrromethene (BODIPY), offer several advantageous characteristics, but can be limiting in multicolor imaging because most ready-made fluorescent reporter constructs fluoresce in the green-to-red region of the visible spectrum. Nile Red emits between green and red, and BODIPY can be photoconverted from green to red fluorescence, limiting its ability to be utilized for time-lapse imaging of living cells. Here, we report the design and synthesis, the photophysical characterization, and biological testing of two easily prepared series of new blue-fluorescing dyes as markers for LDs. Confocal fluorescence microscopy results showed an interesting correlation between the chemical structures of these fluorescent probes and their specific staining patterns. The pyrazole-based compound 11c was found to be a specific dye for LDs, whereas the pyrrole-based compound 10d led to prominent staining of the membranous cell organelles. |
Fuentes-Barros, G; Castro-Saavedra, S; Liberona, L; Acevedo-Fuentes, W; Tirapegui, C; Mattar, C; Cassels, B K Variation of the Alkaloid Content of Peumus Boldus (Boldo) Artículo de revista Fitoterapia, 127 , pp. 179-185, 2018, ISSN: 0367-326x. Resumen | Enlaces | BibTeX | Etiquetas: activity, alkaloids, antioxidant boldine, boldus, herbal in-vitro, inhibition, leaves, medicine, peumus peumus-boldus, phenanthrene phytochemistry, plants, products, reticuline traditional uhplc-ms/ms @article{RN386, title = {Variation of the Alkaloid Content of Peumus Boldus (Boldo)}, author = { G. Fuentes-Barros and S. Castro-Saavedra and L. Liberona and W. Acevedo-Fuentes and C. Tirapegui and C. Mattar and B.K. Cassels}, url = {/brokenurl#<Go to ISI>://WOS:000437551000027}, doi = {10.1016/j.fitote.2018.02.020}, issn = {0367-326x}, year = {2018}, date = {2018-01-01}, journal = {Fitoterapia}, volume = {127}, pages = {179-185}, abstract = {Eighteen alkaloids were detected in the bark, leaves, wood and roots of Peumus boldus, including traces of secoboldine, N-methylsecoboldine (boldine methine), glaucine and norreticuline, not reported previously as constituents of this species. Using appropriate standards, we quantified thirteen of them by UHPLC-MS/MS. Boldine was dominant in the bark, and laurolitsine in wood and roots. The alkaloid composition of the leaves, determined for 130 individually identified trees, classified by age and sex, was highly variable, where N-methyllaurotetanine, laurotetanine, coclaurine and in some cases isocorydine predominated, but not boldine.}, keywords = {activity, alkaloids, antioxidant boldine, boldus, herbal in-vitro, inhibition, leaves, medicine, peumus peumus-boldus, phenanthrene phytochemistry, plants, products, reticuline traditional uhplc-ms/ms}, pubstate = {published}, tppubtype = {article} } Eighteen alkaloids were detected in the bark, leaves, wood and roots of Peumus boldus, including traces of secoboldine, N-methylsecoboldine (boldine methine), glaucine and norreticuline, not reported previously as constituents of this species. Using appropriate standards, we quantified thirteen of them by UHPLC-MS/MS. Boldine was dominant in the bark, and laurolitsine in wood and roots. The alkaloid composition of the leaves, determined for 130 individually identified trees, classified by age and sex, was highly variable, where N-methyllaurotetanine, laurotetanine, coclaurine and in some cases isocorydine predominated, but not boldine. |
Tamayo, L; Acuna, D; Riveros, A; Kogan, M J; Azocar, M; Paez, M; Leal, M; Urzúa, M; Cerda, E Acs Applied Materials & Interfaces, 10 (16), pp. 13361-13372, 2018, ISSN: 1944-8244. Resumen | Enlaces | BibTeX | Etiquetas: antibiofilm, applications, bacterial biomaterials, biomedical gold in-vitro, leaching mechanical molecular-weight, nanocomposites nanoparticles, non-cytotoxic, particle-size, phase-separation, polyurethane, porous properties, scaffolds, techniques, thermoplastic @article{RN405, title = {Porous Nanogold/Polyurethane Scaffolds with Improved Antibiofilm, Mechanical, and Thermal Properties and with Reduced Effects on Cell Viability: A Suitable Material for Soft Tissue Applications}, author = { L. Tamayo and D. Acuna and A. Riveros and M.J. Kogan and M. Azocar and M. Paez and M. Leal and M. Urz\'{u}a and E. Cerda}, url = {/brokenurl#<Go to ISI>://WOS:000431150900013}, doi = {10.1021/acsami.8b02347}, issn = {1944-8244}, year = {2018}, date = {2018-01-01}, journal = {Acs Applied Materials & Interfaces}, volume = {10}, number = {16}, pages = {13361-13372}, abstract = {The use of implants carries on a series of problems, among them infections, poor biocompatibility, high levels of cytotoxicity, and significant mechanical differences between implants and host organs that promote stress shielding effects. These problems indicate that the materials used to make implants must meet essential requirements and high standards for implantations to be successful. In this work, we present the synthesis, characterization and evaluation of the antibiofilm, mechanical, and thermal properties, and cytotoxic effect of a nanocomposite-based scaffold on polyurethane (PU) and gold nanoparticles (AuNPs) for soft tissue applications. The effect of the quantity of AuNPs on the antibacterial activity of nanocomposite scaffolds was evaluated against Staphylococcus epidermidis and Klebsiella spp., with a resulting 99.99% inhibition of both bacteria using a small quantity of nanoparticles. Cytotoxicity was evaluated with the T10 1/2 test against fibroblast cells. The results demonstrated that porous nanogold/PU scaffolds have no toxic effects on fibroblast cells to the 5 day exposition. With respect to mechanical properties, stress strain curves showed that the compressive modulus and yield strength of PU scaffolds were significantly enhanced by AuNPs (by at least 10 times). This is due to changes in the arrangement of hard segments of PU, which increase the stiffness of the polymer. Thermogravimetric analysis showed that the degradation onset temperature rises with an increase in the quantity of AuNPs. These properties and characteristics demonstrate that porous nanogold/PU scaffolds are suitable material for use in soft tissue implants.}, keywords = {antibiofilm, applications, bacterial biomaterials, biomedical gold in-vitro, leaching mechanical molecular-weight, nanocomposites nanoparticles, non-cytotoxic, particle-size, phase-separation, polyurethane, porous properties, scaffolds, techniques, thermoplastic}, pubstate = {published}, tppubtype = {article} } The use of implants carries on a series of problems, among them infections, poor biocompatibility, high levels of cytotoxicity, and significant mechanical differences between implants and host organs that promote stress shielding effects. These problems indicate that the materials used to make implants must meet essential requirements and high standards for implantations to be successful. In this work, we present the synthesis, characterization and evaluation of the antibiofilm, mechanical, and thermal properties, and cytotoxic effect of a nanocomposite-based scaffold on polyurethane (PU) and gold nanoparticles (AuNPs) for soft tissue applications. The effect of the quantity of AuNPs on the antibacterial activity of nanocomposite scaffolds was evaluated against Staphylococcus epidermidis and Klebsiella spp., with a resulting 99.99% inhibition of both bacteria using a small quantity of nanoparticles. Cytotoxicity was evaluated with the T10 1/2 test against fibroblast cells. The results demonstrated that porous nanogold/PU scaffolds have no toxic effects on fibroblast cells to the 5 day exposition. With respect to mechanical properties, stress strain curves showed that the compressive modulus and yield strength of PU scaffolds were significantly enhanced by AuNPs (by at least 10 times). This is due to changes in the arrangement of hard segments of PU, which increase the stiffness of the polymer. Thermogravimetric analysis showed that the degradation onset temperature rises with an increase in the quantity of AuNPs. These properties and characteristics demonstrate that porous nanogold/PU scaffolds are suitable material for use in soft tissue implants. |
Remonsellez, F; Castro-Severyn, J; Pardo-Este, C; Aguilar, P; Fortt, J; Salinas, C; Barahona, S; Leon, J; Fuentes, B; Areche, C; Hernandez, K L; Aguayo, D; Saavedra, C P Characterization and Salt Response in Recurrent Halotolerant Exiguobacterium Sp Sh31 Isolated from Sediments of Salar De Huasco, Chilean Altiplano Artículo de revista Frontiers in Microbiology, 9 , 2018, ISSN: 1664-302x. Resumen | Enlaces | BibTeX | Etiquetas: altiplano, altitude bacillus-subtilis, bacterium, biofilm chilean communities, compatible environmental exiguobacterium, extremophile, formation, halophilic halotolerant, microbial moderately permafrost, pressure, psychrophilic responses saline siberian solutes, sp-nov., stress wetland @article{RN380, title = {Characterization and Salt Response in Recurrent Halotolerant Exiguobacterium Sp Sh31 Isolated from Sediments of Salar De Huasco, Chilean Altiplano}, author = { F. Remonsellez and J. Castro-Severyn and C. Pardo-Este and P. Aguilar and J. Fortt and C. Salinas and S. Barahona and J. Leon and B. Fuentes and C. Areche and K.L. Hernandez and D. Aguayo and C.P. Saavedra}, url = {/brokenurl#<Go to ISI>://WOS:000445093500001}, doi = {10.3389/fmicb.2018.02228}, issn = {1664-302x}, year = {2018}, date = {2018-01-01}, journal = {Frontiers in Microbiology}, volume = {9}, abstract = {Poly-extremophiles microorganisms have the capacity to inhabit hostile environments and can survive several adverse conditions that include as variations in temperature, pH, and salinity, high levels UV light and atmospheric pressure, and even the presence of toxic compounds and the formation of reactive oxygen species (ROS). A halotolerant Exiguobacterium strain was isolated from Salar de Huasco (Chilean Altiplano), a well-known shallow lake area with variable salinity levels, little human intervention, and extreme environmental conditions, which makes it ideal for the study of resistant mechanisms and the evolution of adaptations. This bacterial genus has not been extensively studied, although its cosmopolitan location indicates that it has high levels of plasticity and adaptive capacity. However, to date, there are no studies regarding the tolerance and resistance to salinity and osmotic pressure. We set out to characterize the Exiguobacterium sp. SH31 strain and describe its phenotypical and genotypical response to osmotic stress. In this context, as a first step to characterize the response to the SH31 strain to salinity and to establish the bases for a molecular study, we proposed to compare its response under three salt conditions (0, 25, and 50 g/l NaCl). Using different physiology, genomic, and transcriptomic approaches, we determined that the bacterium is able to grow properly in a NaCl concentration of up to 50 g/l; however, the best growth rate was observed at 25 g/l. Although the presence of flagella is not affected by salinity, motility was diminished at 25 g/l NaCl and abolished at 50 g/l. Biofilm formation was induced proportionally with increases in salinity, which was expected. These phenotypic results correlated with the expression of related genes: fliG and fliS Motility); opuBA and putP (transport); glnA, proC, gltA, and gbsA (compatible solutes); ywqC, bdlA, luxS y pgaC (biofilm and stress response); and therefore, we conclude that this strain effectively modifies gene expression and physiology in a differential manner when faced with different concentrations of NaCl and these modifications aid survival.}, keywords = {altiplano, altitude bacillus-subtilis, bacterium, biofilm chilean communities, compatible environmental exiguobacterium, extremophile, formation, halophilic halotolerant, microbial moderately permafrost, pressure, psychrophilic responses saline siberian solutes, sp-nov., stress wetland}, pubstate = {published}, tppubtype = {article} } Poly-extremophiles microorganisms have the capacity to inhabit hostile environments and can survive several adverse conditions that include as variations in temperature, pH, and salinity, high levels UV light and atmospheric pressure, and even the presence of toxic compounds and the formation of reactive oxygen species (ROS). A halotolerant Exiguobacterium strain was isolated from Salar de Huasco (Chilean Altiplano), a well-known shallow lake area with variable salinity levels, little human intervention, and extreme environmental conditions, which makes it ideal for the study of resistant mechanisms and the evolution of adaptations. This bacterial genus has not been extensively studied, although its cosmopolitan location indicates that it has high levels of plasticity and adaptive capacity. However, to date, there are no studies regarding the tolerance and resistance to salinity and osmotic pressure. We set out to characterize the Exiguobacterium sp. SH31 strain and describe its phenotypical and genotypical response to osmotic stress. In this context, as a first step to characterize the response to the SH31 strain to salinity and to establish the bases for a molecular study, we proposed to compare its response under three salt conditions (0, 25, and 50 g/l NaCl). Using different physiology, genomic, and transcriptomic approaches, we determined that the bacterium is able to grow properly in a NaCl concentration of up to 50 g/l; however, the best growth rate was observed at 25 g/l. Although the presence of flagella is not affected by salinity, motility was diminished at 25 g/l NaCl and abolished at 50 g/l. Biofilm formation was induced proportionally with increases in salinity, which was expected. These phenotypic results correlated with the expression of related genes: fliG and fliS Motility); opuBA and putP (transport); glnA, proC, gltA, and gbsA (compatible solutes); ywqC, bdlA, luxS y pgaC (biofilm and stress response); and therefore, we conclude that this strain effectively modifies gene expression and physiology in a differential manner when faced with different concentrations of NaCl and these modifications aid survival. |
Diaz, C; Valenzuela, M L; Segovia, M; Correa, K; Campa, De La R; Soto, A P Solution, Solid-State Two Step Synthesis and Optical Properties of Zno and Sno2 Nanoparticles and Their Nanocomposites with Sio2 Artículo de revista Journal of Cluster Science, 29 (2), pp. 251-266, 2018, ISSN: 1040-7278. Resumen | Enlaces | BibTeX | Etiquetas: center chitin, chitosan, crystal-structure, dot fine-structure, kinetics, mechanisms, nanostructures, photoluminescence, sio2, size sno2 solid-state synthesis, zinc-oxide, zno @article{RN395, title = {Solution, Solid-State Two Step Synthesis and Optical Properties of Zno and Sno2 Nanoparticles and Their Nanocomposites with Sio2}, author = { C. Diaz and M.L. Valenzuela and M. Segovia and K. Correa and R. De La Campa and A.P. Soto}, url = {/brokenurl#<Go to ISI>://WOS:000425608200006}, doi = {10.1007/s10876-017-1324-8}, issn = {1040-7278}, year = {2018}, date = {2018-01-01}, journal = {Journal of Cluster Science}, volume = {29}, number = {2}, pages = {251-266}, abstract = {Nanostructure luminescent ZnO and SnO2 materials are prepared by a two-step solid-state method based on the solution preparation of the macromolecular precursors ZnCl2 center dot Chitosan and SnCl2 center dot Chitosan having different ratios (1:1, 1:5 and 1:10), their pyrolysis under air at 800 A degrees C. The pyrolytic ZnO and SnO2 nanomaterials show a dependence of the particle size, morphology and luminescent properties with the ratio [metal/polymer] in the MCl2 center dot Chitosan precursors. Thus, ZnO semiconductor materials exhibit luminescence spectra with several emission at 440 nm corresponds to a radiative transition of an electron from the shallow donor level of oxygen vacancies, and the zinc interstitial, to the valence band. On the other hand, the photoluminescence spectrum of the nanostructured SnO2 shows an intense blue luminescence at a wavelength of 420 nm which may be attributed to oxygen-related defects that have been introduced during the growth process of the nanoparticles. Additionally, whereas SnO2 was successfully incorporated into SiO2 structure (SnO2//SiO2) by pyrolysis of solid-state mixtures of the precursors SnCl2 center dot Chitosan in the presence of SiO2, the same reaction carried out with ZnCl2 center dot Chitosan precursors led to a mixture of Zn2SiO4 and SiO2. Thus, this new methodology yields nanostructured semiconductor materials, ZnO and SnO2, suitable for optoelectronic and sensor solid-state devices.}, keywords = {center chitin, chitosan, crystal-structure, dot fine-structure, kinetics, mechanisms, nanostructures, photoluminescence, sio2, size sno2 solid-state synthesis, zinc-oxide, zno}, pubstate = {published}, tppubtype = {article} } Nanostructure luminescent ZnO and SnO2 materials are prepared by a two-step solid-state method based on the solution preparation of the macromolecular precursors ZnCl2 center dot Chitosan and SnCl2 center dot Chitosan having different ratios (1:1, 1:5 and 1:10), their pyrolysis under air at 800 A degrees C. The pyrolytic ZnO and SnO2 nanomaterials show a dependence of the particle size, morphology and luminescent properties with the ratio [metal/polymer] in the MCl2 center dot Chitosan precursors. Thus, ZnO semiconductor materials exhibit luminescence spectra with several emission at 440 nm corresponds to a radiative transition of an electron from the shallow donor level of oxygen vacancies, and the zinc interstitial, to the valence band. On the other hand, the photoluminescence spectrum of the nanostructured SnO2 shows an intense blue luminescence at a wavelength of 420 nm which may be attributed to oxygen-related defects that have been introduced during the growth process of the nanoparticles. Additionally, whereas SnO2 was successfully incorporated into SiO2 structure (SnO2//SiO2) by pyrolysis of solid-state mixtures of the precursors SnCl2 center dot Chitosan in the presence of SiO2, the same reaction carried out with ZnCl2 center dot Chitosan precursors led to a mixture of Zn2SiO4 and SiO2. Thus, this new methodology yields nanostructured semiconductor materials, ZnO and SnO2, suitable for optoelectronic and sensor solid-state devices. |
Meneses-Franco, A; Campos-Vallette, M; Vasquez, S O; Soto-Bustamante, E A Er-Doped Nanostructured Batio3 for Nir to Visible Upconversion Artículo de revista Materials, 11 (10), 2018, ISSN: 1996-1944. Resumen | Enlaces | BibTeX | Etiquetas: barium crystal, dielectric-properties, erbium, fabrication, ions microstructure, nanoparticle, nanoparticles, nanotechnology, particles, photoluminescent, spectra, technology, titanate, upconversion @article{RN409, title = {Er-Doped Nanostructured Batio3 for Nir to Visible Upconversion}, author = { A. Meneses-Franco and M. Campos-Vallette and S.O. Vasquez and E.A. Soto-Bustamante}, url = {/brokenurl#<Go to ISI>://WOS:000448658400164}, doi = {10.3390/ma11101950}, issn = {1996-1944}, year = {2018}, date = {2018-01-01}, journal = {Materials}, volume = {11}, number = {10}, abstract = {Photoluminescent mechanisms in erbium-doped barium titanate nanoparticle systems were studied. Er3+ ions were introduced into the BaTiO3 lattice by the sol-gel method. The resulting Er3+ concentration was between 0% and 5%, with Ba/Ti ratios of 1.008 and 0.993. The stoichiometry of Ba and Ti concentrations in the lattice influenced the doping mechanism and placement of erbium ions in the lattice structure. Our research shows the existence of a strong correlation between Ba/Ti ratios, erbium concentration, phase structure and doping site location on the upconversion photoluminescence mechanisms. Competing upconversion emissions H-2(11/2)/(S3/2I15/2)-S-4-I-4 at 523 and 548 nm respectively and other photoluminescent mechanisms as (I9/2I11/2)-I-4-I-4 around 4000 nm (2500 cm(-1)) were studied using Raman and emission spectroscopy. The upconversion process is predominant over other photoluminescent decay when the material presents high distortion in the surrounding activator.}, keywords = {barium crystal, dielectric-properties, erbium, fabrication, ions microstructure, nanoparticle, nanoparticles, nanotechnology, particles, photoluminescent, spectra, technology, titanate, upconversion}, pubstate = {published}, tppubtype = {article} } Photoluminescent mechanisms in erbium-doped barium titanate nanoparticle systems were studied. Er3+ ions were introduced into the BaTiO3 lattice by the sol-gel method. The resulting Er3+ concentration was between 0% and 5%, with Ba/Ti ratios of 1.008 and 0.993. The stoichiometry of Ba and Ti concentrations in the lattice influenced the doping mechanism and placement of erbium ions in the lattice structure. Our research shows the existence of a strong correlation between Ba/Ti ratios, erbium concentration, phase structure and doping site location on the upconversion photoluminescence mechanisms. Competing upconversion emissions H-2(11/2)/(S3/2I15/2)-S-4-I-4 at 523 and 548 nm respectively and other photoluminescent mechanisms as (I9/2I11/2)-I-4-I-4 around 4000 nm (2500 cm(-1)) were studied using Raman and emission spectroscopy. The upconversion process is predominant over other photoluminescent decay when the material presents high distortion in the surrounding activator. |
Miranda-Rojas, S; Fernandez, I; Kastner, J; Toro-Labbe, A; Mendizabal, F Unraveling the Nature of the Catalytic Power of Fluoroacetate Dehalogenase Artículo de revista Chemcatchem, 10 (5), pp. 1052-1063, 2018, ISSN: 1867-3880. Resumen | Enlaces | BibTeX | Etiquetas: approach, bond, carbon-fluorine catalysis, chemical cluster decomposition density-functional displacement, dynamics, energy enzyme force, mechanism model, molecular-orbital qm/mm, transition-state @article{RN394, title = {Unraveling the Nature of the Catalytic Power of Fluoroacetate Dehalogenase}, author = { S. Miranda-Rojas and I. Fernandez and J. Kastner and A. Toro-Labbe and F. Mendizabal}, url = {/brokenurl#<Go to ISI>://WOS:000426844600026}, doi = {10.1002/cctc.201701517}, issn = {1867-3880}, year = {2018}, date = {2018-01-01}, journal = {Chemcatchem}, volume = {10}, number = {5}, pages = {1052-1063}, abstract = {Fluoroacetate dehalogenase is able to cleavage a carbon-fluoride bond, the strongest carbon-halogen bond in nature, in a process initiated by a S(N)2 reaction. The role of the enzyme machinery and particularly of the halogen pocket in the S(N)2 reaction is thoroughly explored by using state-of-the-art computational tools. A comparison between the non-catalyzed versus enzyme-catalyzed reaction, as well as with a mutant of the enzyme (Tyr219Phe), is presented. The energy barrier changes are rationalized by means of reaction force analysis and the activation strain model coupled with energy decomposition analysis. The catalysis is in part caused by the reduction of structural work from bringing the reactant species towards the proper reaction orientation, and the reduction of the electrostatic repulsion between the nucleophile and the substrate, which are both negatively charged. In addition, catalysis is also driven by an important reduction of the electronic reorganization processes during the reaction, where Tyr from the halogen pocket acts as a charge acceptor from the S(N)2 reaction axis therefore reducing the electronic steric repulsion between the reacting parts.}, keywords = {approach, bond, carbon-fluorine catalysis, chemical cluster decomposition density-functional displacement, dynamics, energy enzyme force, mechanism model, molecular-orbital qm/mm, transition-state}, pubstate = {published}, tppubtype = {article} } Fluoroacetate dehalogenase is able to cleavage a carbon-fluoride bond, the strongest carbon-halogen bond in nature, in a process initiated by a S(N)2 reaction. The role of the enzyme machinery and particularly of the halogen pocket in the S(N)2 reaction is thoroughly explored by using state-of-the-art computational tools. A comparison between the non-catalyzed versus enzyme-catalyzed reaction, as well as with a mutant of the enzyme (Tyr219Phe), is presented. The energy barrier changes are rationalized by means of reaction force analysis and the activation strain model coupled with energy decomposition analysis. The catalysis is in part caused by the reduction of structural work from bringing the reactant species towards the proper reaction orientation, and the reduction of the electrostatic repulsion between the nucleophile and the substrate, which are both negatively charged. In addition, catalysis is also driven by an important reduction of the electronic reorganization processes during the reaction, where Tyr from the halogen pocket acts as a charge acceptor from the S(N)2 reaction axis therefore reducing the electronic steric repulsion between the reacting parts. |
Ardiles, A; Barrientos, R; Simirgiotis, M J; Borquez, J; Sepulveda, B; Areche, C Gastroprotective Activity of Parastrephia Quadrangularis (Meyen), Cabrera from the Atacama Desert Artículo de revista Molecules, 23 (9), 2018, ISSN: 1420-3049. Resumen | Enlaces | BibTeX | Etiquetas: clerodanes, derivatives, diterpenoids, endemic extracts, gastric gastroprotective, lc-ms/ms, lesions, medicine, mode, natural-products, plants, prostaglandins, rats tremetones, ulcer @article{RN379, title = {Gastroprotective Activity of Parastrephia Quadrangularis (Meyen), Cabrera from the Atacama Desert}, author = { A. Ardiles and R. Barrientos and M.J. Simirgiotis and J. Borquez and B. Sepulveda and C. Areche}, url = {/brokenurl#<Go to ISI>://WOS:000447365100272}, doi = {10.3390/molecules23092361}, issn = {1420-3049}, year = {2018}, date = {2018-01-01}, journal = {Molecules}, volume = {23}, number = {9}, abstract = {Forty-three metabolites including several methoxylated flavonoids, tremetones, and ent-clerodane diterpenes were accurately identified for the first time in the ethanolic extract of P. quadrangularis by means of hyphenated UHPLC-quadrupole Orbitrap mass spectrometry, and seven isolated compounds were tested regarding gastroprotective activity using the HCl/EtOH-induced lesion model in mice. A new tremetone (compound 6) is reported based on spectroscopic evidence. The isolated clerodanes and tremetones showed gastroprotective activity in a mouse model, evidenced by compound 7 (p-coumaroyloxytremetone), which showed the highest gastroprotective activity (76%), which was higher than the control drug lansoprazole (72%). Our findings revealed that several constituents of this plant have gastroprotective activity, and particularly, p-coumaroyloxytremetone could be considered as a lead molecule to explore new gastroprotective agents. This plant is a rich source of biologically active tremetones and terpenoids which can support the ethnobotanical use of the plant.}, keywords = {clerodanes, derivatives, diterpenoids, endemic extracts, gastric gastroprotective, lc-ms/ms, lesions, medicine, mode, natural-products, plants, prostaglandins, rats tremetones, ulcer}, pubstate = {published}, tppubtype = {article} } Forty-three metabolites including several methoxylated flavonoids, tremetones, and ent-clerodane diterpenes were accurately identified for the first time in the ethanolic extract of P. quadrangularis by means of hyphenated UHPLC-quadrupole Orbitrap mass spectrometry, and seven isolated compounds were tested regarding gastroprotective activity using the HCl/EtOH-induced lesion model in mice. A new tremetone (compound 6) is reported based on spectroscopic evidence. The isolated clerodanes and tremetones showed gastroprotective activity in a mouse model, evidenced by compound 7 (p-coumaroyloxytremetone), which showed the highest gastroprotective activity (76%), which was higher than the control drug lansoprazole (72%). Our findings revealed that several constituents of this plant have gastroprotective activity, and particularly, p-coumaroyloxytremetone could be considered as a lead molecule to explore new gastroprotective agents. This plant is a rich source of biologically active tremetones and terpenoids which can support the ethnobotanical use of the plant. |
Cassels, B K; Saez-Briones, P Dark Classics in Chemical Neuroscience: Mescaline Artículo de revista Acs Chemical Neuroscience, 9 (10), pp. 2448-2458, 2018, ISSN: 1948-7193. Resumen | Enlaces | BibTeX | Etiquetas: analogs, biosynthesis, cancer, derivatives, diethylamide, hallucinogen, hallucinogenic life-threatening lysergic-acid mescaline, metabolism, pedro, peyote, pharmacology, phenethylamine, phenyl-aethylamine, properties, relationships, san serotonin stimulus structure-activity synthesis, wachuma @article{RN389, title = {Dark Classics in Chemical Neuroscience: Mescaline}, author = { B.K. Cassels and P. Saez-Briones}, url = {/brokenurl#<Go to ISI>://WOS:000447954300015}, doi = {10.1021/acschemneuro.8b00215}, issn = {1948-7193}, year = {2018}, date = {2018-01-01}, journal = {Acs Chemical Neuroscience}, volume = {9}, number = {10}, pages = {2448-2458}, abstract = {Archeological studies in the United States, Mexico, and Peru suggest that mescaline, as a cactus constituent, has been used for more than 6000 years. Although it is a widespread cactus alkaloid, it is present in high concentrations in few species, notably the North American peyote (Lophophora williamsii) and the South American wachuma (Trichocereus pachanoi, T. peruvianus, and T. bridgesii). Spanish 16th century chroniclers considered these cacti "diabolic", leading to their prohibition, but their use persisted to our days and has been spreading for the last 150 years. In the late 1800s, peyote attracted scientific attention; mescaline was isolated, and its role in the psychedelic effects of peyote tops or "mescal buttons" was demonstrated. Its structure was established by synthesis in 1929, and alternative routes were developed, providing larger amounts for pharmacological and biosynthetic research. Although its effects are attributed mainly to its action as a 5-HT2A serotonin receptor agonist, mescaline binds in a similar concentration range to 5-HT1A and alpha(2A) receptors. It is largely excreted unchanged in human urine, and its metabolic products are apparently unrelated to its psychedelic properties. Its low potency is probably responsible for its relative neglect by recreational substance users, as the successful search for structure-activity relationships in the hallucinogen field focused largely on finding more potent analogues. Renewed interest in the possible therapeutic applications of psychedelic drugs may hopefully lead to novel insights regarding the commonalities and differences between the actions of individual classic hallucinogens.}, keywords = {analogs, biosynthesis, cancer, derivatives, diethylamide, hallucinogen, hallucinogenic life-threatening lysergic-acid mescaline, metabolism, pedro, peyote, pharmacology, phenethylamine, phenyl-aethylamine, properties, relationships, san serotonin stimulus structure-activity synthesis, wachuma}, pubstate = {published}, tppubtype = {article} } Archeological studies in the United States, Mexico, and Peru suggest that mescaline, as a cactus constituent, has been used for more than 6000 years. Although it is a widespread cactus alkaloid, it is present in high concentrations in few species, notably the North American peyote (Lophophora williamsii) and the South American wachuma (Trichocereus pachanoi, T. peruvianus, and T. bridgesii). Spanish 16th century chroniclers considered these cacti "diabolic", leading to their prohibition, but their use persisted to our days and has been spreading for the last 150 years. In the late 1800s, peyote attracted scientific attention; mescaline was isolated, and its role in the psychedelic effects of peyote tops or "mescal buttons" was demonstrated. Its structure was established by synthesis in 1929, and alternative routes were developed, providing larger amounts for pharmacological and biosynthetic research. Although its effects are attributed mainly to its action as a 5-HT2A serotonin receptor agonist, mescaline binds in a similar concentration range to 5-HT1A and alpha(2A) receptors. It is largely excreted unchanged in human urine, and its metabolic products are apparently unrelated to its psychedelic properties. Its low potency is probably responsible for its relative neglect by recreational substance users, as the successful search for structure-activity relationships in the hallucinogen field focused largely on finding more potent analogues. Renewed interest in the possible therapeutic applications of psychedelic drugs may hopefully lead to novel insights regarding the commonalities and differences between the actions of individual classic hallucinogens. |
Moris, S; Manriquez, V; Barahona, P; Galdámez, A; Valencia-Galvez, P Electrical and Optical Properties of P-Type Ag(0.3)Cu(0.7)Inq(2) Chalcopyrite Semiconductors Artículo de revista Chalcogenide Letters, 15 (12), pp. 615-623, 2018, ISSN: 1584-8663. Resumen | Enlaces | BibTeX | Etiquetas: chalcopyrite-type, compound, cugase2 cuinse2, cuinte2, i-iii-vi2, p-type, selenization, semiconductor solar-cells, sulfurization, ternary, thin-films @article{RN398, title = {Electrical and Optical Properties of P-Type Ag(0.3)Cu(0.7)Inq(2) Chalcopyrite Semiconductors}, author = { S. Moris and V. Manriquez and P. Barahona and A. Gald\'{a}mez and P. Valencia-Galvez}, url = {/brokenurl#<Go to ISI>://WOS:000452412600004}, issn = {1584-8663}, year = {2018}, date = {2018-01-01}, journal = {Chalcogenide Letters}, volume = {15}, number = {12}, pages = {615-623}, abstract = {We report the synthesis, characterization and electrical properties of Ag0.3Cu0.7InS2, Ag0.3Cu0.7InSe2 and Ag0.3Cu0.7InTe2. These solid solutions were synthesized via microwave-assisted solid-state reactions. Powder X-ray diffraction patterns were indexed in the space group I (4) over bar 2d. The chemical compositions were determined by scanning electron microcopy. The analysis of the vibrational properties was performed by Raman scattering measurements. The Raman peaks were analyzed by fitting the spectra and allowed the identification of the vibrational modes via comparison with experimental and theoretical data from CuInQ(2) ( Q = S, Se, Te) end-members. Ag0.3Cu0.7InS2 and Ag0.3Cu0.7InTe2 exhibit typical semiconductor p-type behavior with a carrier concentration of similar to +10(16) cm(-3). The electrical conductivities sigma at R.T. were similar to 10(-1) S cm(-1) and similar to 1.0 S cm(-1) for Ag0.3Cu0.7InS2 and Ag0.3Cu0.7InTe2, respectively. The optical band gaps, based on the UV-Vis-NIR spectra, were E-g similar to 1.50 eV.}, keywords = {chalcopyrite-type, compound, cugase2 cuinse2, cuinte2, i-iii-vi2, p-type, selenization, semiconductor solar-cells, sulfurization, ternary, thin-films}, pubstate = {published}, tppubtype = {article} } We report the synthesis, characterization and electrical properties of Ag0.3Cu0.7InS2, Ag0.3Cu0.7InSe2 and Ag0.3Cu0.7InTe2. These solid solutions were synthesized via microwave-assisted solid-state reactions. Powder X-ray diffraction patterns were indexed in the space group I (4) over bar 2d. The chemical compositions were determined by scanning electron microcopy. The analysis of the vibrational properties was performed by Raman scattering measurements. The Raman peaks were analyzed by fitting the spectra and allowed the identification of the vibrational modes via comparison with experimental and theoretical data from CuInQ(2) ( Q = S, Se, Te) end-members. Ag0.3Cu0.7InS2 and Ag0.3Cu0.7InTe2 exhibit typical semiconductor p-type behavior with a carrier concentration of similar to +10(16) cm(-3). The electrical conductivities sigma at R.T. were similar to 10(-1) S cm(-1) and similar to 1.0 S cm(-1) for Ag0.3Cu0.7InS2 and Ag0.3Cu0.7InTe2, respectively. The optical band gaps, based on the UV-Vis-NIR spectra, were E-g similar to 1.50 eV. |
Gomez-Jeria, J S; Clavijo, E; Carcamo, J J; Gutierrez, S An Infrared and Sem Study of the Margins of Some German Hyperinflation Postage Stamps Artículo de revista Research Journal of Pharmaceutical Biological and Chemical Sciences, 9 (2), pp. 870-892, 2018, ISSN: 0975-8585. Resumen | Enlaces | BibTeX | Etiquetas: archeology, archeophilately, cellulose, database, electron ft-ir germany, hyperinflation, infrared inks kaolinite, microscopy, oxides, pigments, postage raman scanning sem, spectra, spectral spectroscopy, stamps, white zinc @article{RN411, title = {An Infrared and Sem Study of the Margins of Some German Hyperinflation Postage Stamps}, author = { J.S. Gomez-Jeria and E. Clavijo and J.J. Carcamo and S. Gutierrez}, url = {/brokenurl#<Go to ISI>://WOS:000432267600105}, issn = {0975-8585}, year = {2018}, date = {2018-01-01}, journal = {Research Journal of Pharmaceutical Biological and Chemical Sciences}, volume = {9}, number = {2}, pages = {870-892}, abstract = {Infrared spectroscopy and scanning electron microscopy (SEM) studies were performed on the margins (the area without printed colors) of a set of German postage stamps dated 1923 and corresponding to the hyperinflationary period of economy. SEM results showed the presence of Al, Si, Zn and S in the samples, but in different combinations. Sulfur is considered to be a contaminant. The Al-Si combination is credited to kaolinite, Zn to ZnO and unaccompanied Al possibly to Al2O3. Several experimental IR bands of kaolinite agree with the suggestion of its existence in some stamps. In the case of Al and Zn alone we have supposed that, with the passing of time and with the help of moisture, AlOH and ZnOH were formed in a quantity allowing detecting some of the metal- OH bands by IR spectroscopy. On the basis of previous infrared experimental results on Al and Zn hydroxides we assigned some IR bands to the OH groups bonded to these metals. Our results indicate that it is highly probable that the paper used to print these postage stamps was originated in more than one paper mill.}, keywords = {archeology, archeophilately, cellulose, database, electron ft-ir germany, hyperinflation, infrared inks kaolinite, microscopy, oxides, pigments, postage raman scanning sem, spectra, spectral spectroscopy, stamps, white zinc}, pubstate = {published}, tppubtype = {article} } Infrared spectroscopy and scanning electron microscopy (SEM) studies were performed on the margins (the area without printed colors) of a set of German postage stamps dated 1923 and corresponding to the hyperinflationary period of economy. SEM results showed the presence of Al, Si, Zn and S in the samples, but in different combinations. Sulfur is considered to be a contaminant. The Al-Si combination is credited to kaolinite, Zn to ZnO and unaccompanied Al possibly to Al2O3. Several experimental IR bands of kaolinite agree with the suggestion of its existence in some stamps. In the case of Al and Zn alone we have supposed that, with the passing of time and with the help of moisture, AlOH and ZnOH were formed in a quantity allowing detecting some of the metal- OH bands by IR spectroscopy. On the basis of previous infrared experimental results on Al and Zn hydroxides we assigned some IR bands to the OH groups bonded to these metals. Our results indicate that it is highly probable that the paper used to print these postage stamps was originated in more than one paper mill. |
Gil-Durán, C; Ravanal, M C; Ubilla, P; Vaca, I; Chávez, R Heterologous Expression, Purification and Characterization of a Highly Thermolabile Endoxylanase from the Antarctic Fungus Cladosporium Sp Artículo de revista Fungal Biology, 122 (9), pp. 875-882, 2018, ISSN: 1878-6146. Resumen | Enlaces | BibTeX | Etiquetas: Antarctica, Cold-active Cold-adapted Low Xylan enzyme, fungus, thermostability @article{RN383, title = {Heterologous Expression, Purification and Characterization of a Highly Thermolabile Endoxylanase from the Antarctic Fungus Cladosporium Sp}, author = { C. Gil-Dur\'{a}n and M.C. Ravanal and P. Ubilla and I. Vaca and R. Ch\'{a}vez}, url = {http://www.sciencedirect.com/science/article/pii/S187861461830093X}, doi = {10.1016/j.funbio.2018.05.002}, issn = {1878-6146}, year = {2018}, date = {2018-01-01}, journal = {Fungal Biology}, volume = {122}, number = {9}, pages = {875-882}, abstract = {Numerous endoxylanases from mesophilic fungi have been purified and characterized. However, endoxylanases from cold-adapted fungi, especially those from Antarctica, have been less studied. In this work, a cDNA from the Antarctic fungus Cladosporium sp. with similarity to endoxylanases from glycosyl hydrolase family 10, was cloned and expressed in Pichia pastoris. The pure recombinant enzyme (named XynA) showed optimal activity on xylan at 50 °C and pH 6\textendash7. The enzyme releases xylooligosaccharides but not xylose, indicating that XynA is a classical endoxylanase. The enzyme was most active on xylans with high content of arabinose (rye arabinoylan and wheat arabinoxylan) than on xylans with low content of arabinose (oat spelts xylan, birchwood xylan and beechwood xylan). Finally, XynA showed a very low thermostability. After 20\textendash30 min of incubation at 40 °C, the enzyme was completely inactivated, suggesting that XynA would be the most thermolabile endoxylanase described so far in filamentous fungi. This is one of the few reports describing the heterologous expression and characterization of a xylanase from a fungus isolated from Antarctica.}, keywords = {Antarctica, Cold-active Cold-adapted Low Xylan enzyme, fungus, thermostability}, pubstate = {published}, tppubtype = {article} } Numerous endoxylanases from mesophilic fungi have been purified and characterized. However, endoxylanases from cold-adapted fungi, especially those from Antarctica, have been less studied. In this work, a cDNA from the Antarctic fungus Cladosporium sp. with similarity to endoxylanases from glycosyl hydrolase family 10, was cloned and expressed in Pichia pastoris. The pure recombinant enzyme (named XynA) showed optimal activity on xylan at 50 °C and pH 6–7. The enzyme releases xylooligosaccharides but not xylose, indicating that XynA is a classical endoxylanase. The enzyme was most active on xylans with high content of arabinose (rye arabinoylan and wheat arabinoxylan) than on xylans with low content of arabinose (oat spelts xylan, birchwood xylan and beechwood xylan). Finally, XynA showed a very low thermostability. After 20–30 min of incubation at 40 °C, the enzyme was completely inactivated, suggesting that XynA would be the most thermolabile endoxylanase described so far in filamentous fungi. This is one of the few reports describing the heterologous expression and characterization of a xylanase from a fungus isolated from Antarctica. |
Salazar, S; Guerra, D; Yutronic, N; Jara, P Removal of Aromatic Chlorinated Pesticides from Aqueous Solution Using Β-Cyclodextrin Polymers Decorated with Fe₃o₄ Nanoparticles Artículo de revista Polymers, 10 (9), pp. 1038, 2018, ISSN: 2073-4360. Resumen | Enlaces | BibTeX | Etiquetas: adsorption, cyclodextrin magnetic nano nanoparticles, nanosponges, sorbents, treatment, water β-cyclodextrin @article{RN393, title = {Removal of Aromatic Chlorinated Pesticides from Aqueous Solution Using Β-Cyclodextrin Polymers Decorated with Fe₃o₄ Nanoparticles}, author = { S. Salazar and D. Guerra and N. Yutronic and P. Jara}, url = {https://www.ncbi.nlm.nih.gov/pubmed/30960963, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6403796/}, doi = {10.3390/polym10091038}, issn = {2073-4360}, year = {2018}, date = {2018-01-01}, journal = {Polymers}, volume = {10}, number = {9}, pages = {1038}, abstract = {This article describes the sorption properties of cyclodextrin polymers (nanosponges; NS) with the pesticides 4-chlorophenoxyacetic acid (4-CPA) and 2,3,4,6-tetrachlorophenol (TCF), including an evaluation of its efficiency and a comparison with other materials, such as granulated activated carbon (GAC). NS-pesticide complexes were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray powder diffraction (XRPD), proton nuclear magnetic resonance (¹H-NMR), UV⁻VIS, and thermogravimetric analysis (TGA). This confirms the interactions of the guests with nanosponges and shows that the polymers have favorable sorption capacities for chlorinated aromatic guests. Our studies also show that the inclusion complex is predominantly favored for NS/CPA rather than those formed between TCF and NS due to the size of the adsorbate and steric effects. Sorption studies carried with repeated cycles demonstrate that NS polymers could be an improved technology for pollutant removal from aquatic environments, as they are very efficient and reusable materials. Our experiments and characterization by SEM, EDS, UV⁻VIS, and magnetization saturation (VSM) also show that NS is an optimal substrate for the deposition of magnetite nanoparticles, thus improving the usefulness and properties of the polymer, as the nanosponges could be retrieved from aqueous solution with a neodymium magnet without losing its efficiency as a pesticide sorbent.}, keywords = {adsorption, cyclodextrin magnetic nano nanoparticles, nanosponges, sorbents, treatment, water β-cyclodextrin}, pubstate = {published}, tppubtype = {article} } This article describes the sorption properties of cyclodextrin polymers (nanosponges; NS) with the pesticides 4-chlorophenoxyacetic acid (4-CPA) and 2,3,4,6-tetrachlorophenol (TCF), including an evaluation of its efficiency and a comparison with other materials, such as granulated activated carbon (GAC). NS-pesticide complexes were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray powder diffraction (XRPD), proton nuclear magnetic resonance (¹H-NMR), UV⁻VIS, and thermogravimetric analysis (TGA). This confirms the interactions of the guests with nanosponges and shows that the polymers have favorable sorption capacities for chlorinated aromatic guests. Our studies also show that the inclusion complex is predominantly favored for NS/CPA rather than those formed between TCF and NS due to the size of the adsorbate and steric effects. Sorption studies carried with repeated cycles demonstrate that NS polymers could be an improved technology for pollutant removal from aquatic environments, as they are very efficient and reusable materials. Our experiments and characterization by SEM, EDS, UV⁻VIS, and magnetization saturation (VSM) also show that NS is an optimal substrate for the deposition of magnetite nanoparticles, thus improving the usefulness and properties of the polymer, as the nanosponges could be retrieved from aqueous solution with a neodymium magnet without losing its efficiency as a pesticide sorbent. |
Silva, N; Riveros, A; Yutronic, N; Lang, E; Chornik, B; Guerrero, S; Samitier, J; Jara, P; Kogan, M J Photothermally Controlled Methotrexate Release System Using Beta-Cyclodextrin and Gold Nanoparticles Artículo de revista Nanomaterials, 8 (12), 2018, ISSN: 2079-4991. Resumen | Enlaces | BibTeX | Etiquetas: binding, citrate complex, compound, cyclodextrin, delivery delivery, gold hepatotoxicity, inclusion irradiation, laser, methotrexate, nanoparticles, oxidative photothermal release, stabilization, stress, system, therapy @article{RN392, title = {Photothermally Controlled Methotrexate Release System Using Beta-Cyclodextrin and Gold Nanoparticles}, author = { N. Silva and A. Riveros and N. Yutronic and E. Lang and B. Chornik and S. Guerrero and J. Samitier and P. Jara and M.J. Kogan}, url = {/brokenurl#<Go to ISI>://WOS:000455323100023}, doi = {10.3390/nano8120985}, issn = {2079-4991}, year = {2018}, date = {2018-01-01}, journal = {Nanomaterials}, volume = {8}, number = {12}, abstract = {The inclusion compound (IC) of cyclodextrin (CD) containing the antitumor drug Methotrexate (MTX) as a guest molecule was obtained to increase the solubility of MTX and decrease its inherent toxic effects in nonspecific cells. The IC was conjugated with gold nanoparticles (AuNPs), obtained by a chemical method, creating a ternary intelligent delivery system for MTX molecules, based on the plasmonic properties of the AuNPs. Irradiation of the ternary system, with a laser wavelength tunable with the corresponding surface plasmon of AuNPs, causes local energy dissipation, producing the controlled release of the guest from CD cavities. Finally, cell viability was evaluated using MTS assays for beta-CD/MTX and AuNPs + beta-CD/MTX samples, with and without irradiation, against HeLa tumor cells. The irradiated sample of the ternary system AuNPs + beta-CD/MTX produced a diminution in cell viability attributed to the photothermal release of MTX.}, keywords = {binding, citrate complex, compound, cyclodextrin, delivery delivery, gold hepatotoxicity, inclusion irradiation, laser, methotrexate, nanoparticles, oxidative photothermal release, stabilization, stress, system, therapy}, pubstate = {published}, tppubtype = {article} } The inclusion compound (IC) of cyclodextrin (CD) containing the antitumor drug Methotrexate (MTX) as a guest molecule was obtained to increase the solubility of MTX and decrease its inherent toxic effects in nonspecific cells. The IC was conjugated with gold nanoparticles (AuNPs), obtained by a chemical method, creating a ternary intelligent delivery system for MTX molecules, based on the plasmonic properties of the AuNPs. Irradiation of the ternary system, with a laser wavelength tunable with the corresponding surface plasmon of AuNPs, causes local energy dissipation, producing the controlled release of the guest from CD cavities. Finally, cell viability was evaluated using MTS assays for beta-CD/MTX and AuNPs + beta-CD/MTX samples, with and without irradiation, against HeLa tumor cells. The irradiated sample of the ternary system AuNPs + beta-CD/MTX produced a diminution in cell viability attributed to the photothermal release of MTX. |
Gomez-Jeria, J S; Clavijo, E; Gutierrez, S An Infrared and Sem Study of the Margins of Some Estonian Postage Stamps Artículo de revista Research Journal of Pharmaceutical Biological and Chemical Sciences, 9 (3), pp. 1258-1279, 2018, ISSN: 0975-8585. Resumen | Enlaces | BibTeX | Etiquetas: archeology, archeophilately, cellulose, electron estonia, infrared microscopy, philately postage scanning sem, spectra, stamps @article{RN412, title = {An Infrared and Sem Study of the Margins of Some Estonian Postage Stamps}, author = { J.S. Gomez-Jeria and E. Clavijo and S. Gutierrez}, url = {/brokenurl#<Go to ISI>://WOS:000438847100169}, issn = {0975-8585}, year = {2018}, date = {2018-01-01}, journal = {Research Journal of Pharmaceutical Biological and Chemical Sciences}, volume = {9}, number = {3}, pages = {1258-1279}, abstract = {Infrared spectroscopy and scanning electron microscopy (SEM) studies were performed on the margins of a set of eighteen Estonian postage stamps dated between 1918 and 1924. SEM results showed the presence of Al, Si and Zn in the samples in different combinations. Two stamps contain kaolin and one ZnO. We could not find a clear relationship between the structure of the IR spectrum and the assumed geographical origin of the papers, but the need to accumulate a large set of results to use statistical methods is clear.}, keywords = {archeology, archeophilately, cellulose, electron estonia, infrared microscopy, philately postage scanning sem, spectra, stamps}, pubstate = {published}, tppubtype = {article} } Infrared spectroscopy and scanning electron microscopy (SEM) studies were performed on the margins of a set of eighteen Estonian postage stamps dated between 1918 and 1924. SEM results showed the presence of Al, Si and Zn in the samples in different combinations. Two stamps contain kaolin and one ZnO. We could not find a clear relationship between the structure of the IR spectrum and the assumed geographical origin of the papers, but the need to accumulate a large set of results to use statistical methods is clear. |
Gazitua, M; Tapia, R A; Contreras, R; Campodonico, P R Effect of the Nature of the Nucleophile and Solvent on an Snar Reaction Artículo de revista New Journal of Chemistry, 42 (1), pp. 260-264, 2018, ISSN: 1144-0546. Resumen | Enlaces | BibTeX | Etiquetas: amines, aromatic aryl azides, conventional ionic kinetics, liquids, preferential reaction-mechanism, regioselectivity solvation, solvents, substitutions, temperature @article{RN422, title = {Effect of the Nature of the Nucleophile and Solvent on an Snar Reaction}, author = { M. Gazitua and R.A. Tapia and R. Contreras and P.R. Campodonico}, url = {/brokenurl#<Go to ISI>://WOS:000418369000027}, doi = {10.1039/c7nj03212a}, issn = {1144-0546}, year = {2018}, date = {2018-01-01}, journal = {New Journal of Chemistry}, volume = {42}, number = {1}, pages = {260-264}, abstract = {The reaction of 2,4-dinitrobenzenesulfonyl chloride toward propylamine was kinetically evaluated in 19 organic solvents and 10 ionic liquids as reaction media. This study was compared with a previous study to experimentally show that solvent effects and the nature of the reacting pair drastically affect the reaction rate and the reaction mechanism. While the reaction of the reference electrophile 2,4-dinitrobenzenesulfonyl chloride with piperidine is favored in polar solvents with the ability to donate or accept hydrogen bonds, the reaction with propylamine is favored in solvents with the ability to accept hydrogen bonds.}, keywords = {amines, aromatic aryl azides, conventional ionic kinetics, liquids, preferential reaction-mechanism, regioselectivity solvation, solvents, substitutions, temperature}, pubstate = {published}, tppubtype = {article} } The reaction of 2,4-dinitrobenzenesulfonyl chloride toward propylamine was kinetically evaluated in 19 organic solvents and 10 ionic liquids as reaction media. This study was compared with a previous study to experimentally show that solvent effects and the nature of the reacting pair drastically affect the reaction rate and the reaction mechanism. While the reaction of the reference electrophile 2,4-dinitrobenzenesulfonyl chloride with piperidine is favored in polar solvents with the ability to donate or accept hydrogen bonds, the reaction with propylamine is favored in solvents with the ability to accept hydrogen bonds. |
Pinto, C; Galdámez, A; Barahona, P; Moris, S; Pena, O Crystal Structure, Raman Scattering and Magnetic Properties of Cucr2-Xzrxse4 and Cucr2-Xsnxse4 Selenospinels Artículo de revista Journal of Magnetism and Magnetic Materials, 456 , pp. 160-166, 2018, ISSN: 0304-8853. Resumen | Enlaces | BibTeX | Etiquetas: colossal crystal geometry magnetic magnetoresistance, properties, raman selenospinel, spectroscopy, structure @article{RN401, title = {Crystal Structure, Raman Scattering and Magnetic Properties of Cucr2-Xzrxse4 and Cucr2-Xsnxse4 Selenospinels}, author = { C. Pinto and A. Gald\'{a}mez and P. Barahona and S. Moris and O. Pena}, url = {/brokenurl#<Go to ISI>://WOS:000427580800023}, doi = {10.1016/j.jmmm.2018.02.023}, issn = {0304-8853}, year = {2018}, date = {2018-01-01}, journal = {Journal of Magnetism and Magnetic Materials}, volume = {456}, pages = {160-166}, publisher = {2018 Elsevier B.V.}, abstract = {Selenospinels, CuCr2-xMxSe4 (M = Zr and Sn), were synthesized via conventional solid-state reactions. The crystal structure of CuCr1.5Sn0.5Se4, CuCr1.7Sn0.3Se4, CuCr1.5Zr0.5Se4, and CuCr1.8Zr0.2Se4 were determined using single-crystal X-ray diffraction. All the phases crystallized in a cubic spinel-type structure. The chemical compositions of the single-crystals were examined using energy-dispersive X-ray analysis (EDS). Powder X-ray diffraction patterns of CuCr1.3Sn0.7Se4 and CuCr1.7Sn0.3Se4 were consistent with phases belonging to the Fd3m Space group. An analysis of the vibrational properties on the single-crystals was performed using Raman scattering measurements. The magnetic properties showed a spin glass behavior with increasing Sn content and ferromagnetic order for CuCr1.7Sn0.3Se4.}, keywords = {colossal crystal geometry magnetic magnetoresistance, properties, raman selenospinel, spectroscopy, structure}, pubstate = {published}, tppubtype = {article} } Selenospinels, CuCr2-xMxSe4 (M = Zr and Sn), were synthesized via conventional solid-state reactions. The crystal structure of CuCr1.5Sn0.5Se4, CuCr1.7Sn0.3Se4, CuCr1.5Zr0.5Se4, and CuCr1.8Zr0.2Se4 were determined using single-crystal X-ray diffraction. All the phases crystallized in a cubic spinel-type structure. The chemical compositions of the single-crystals were examined using energy-dispersive X-ray analysis (EDS). Powder X-ray diffraction patterns of CuCr1.3Sn0.7Se4 and CuCr1.7Sn0.3Se4 were consistent with phases belonging to the Fd3m Space group. An analysis of the vibrational properties on the single-crystals was performed using Raman scattering measurements. The magnetic properties showed a spin glass behavior with increasing Sn content and ferromagnetic order for CuCr1.7Sn0.3Se4. |
Allende-González, P; Laguna-Bercero, M A; Barrientos-Poblete, L; Valenzuela, M L; Diaz, C Solid State Tuning of Tio2 Morphology, Crystal Phase, and Size through Metal Macromolecular Complexes and Its Significance in the Photocatalytic Response Artículo de revista Acs Applied Energy Materials, 1 (7), pp. 3159-3170, 2018, ISSN: 2574-0962. Resumen | Enlaces | BibTeX | Etiquetas: anatase, morphology, nanocrystalline nanoparticles, organic particle-size, phase, photocatalysis, pollutants, rutile size solid-state synthesis, tio2 tio2, titanium-oxides @article{RN396, title = {Solid State Tuning of Tio2 Morphology, Crystal Phase, and Size through Metal Macromolecular Complexes and Its Significance in the Photocatalytic Response}, author = { P. Allende-Gonz\'{a}lez and M.A. Laguna-Bercero and L. Barrientos-Poblete and M.L. Valenzuela and C. Diaz}, url = {/brokenurl#<Go to ISI>://WOS:000458706000021}, doi = {10.1021/acsaem.8b00374}, issn = {2574-0962}, year = {2018}, date = {2018-01-01}, journal = {Acs Applied Energy Materials}, volume = {1}, number = {7}, pages = {3159-3170}, abstract = {A solid-state phase control of TiO2 by the use of different macromolecular complex precursors is reported for the first time. During the formation of TiO2 nanoparticles, chitosan and poly(styrene-co-4-vinylpyridine) polymers can act as solid-state template producing areas after carbonization, where the TiO2 nucleates. It seems that the location of metal centers through the polymeric chain (i.e., the distance between the metal centers) strongly influences the morphology and particle size of the photocatalyst. To demonstrate the application value of our different TiO2 structures, the photocatalytic behavior was explored. The efficient photocatalytic decoloration of methylene blue on different polymorphic forms of nanostructured TiO2 is confirmed. The best photocatalyst achieved a 98% discoloration rate in only 25 min when the pH of the solution was 9.5, improving the efficiency of the standard photocatalyst Degussa P25 without the addition of other phases or dopants. The novelty of the present work is that, by means of an appropriate synthesis, the three main factors (morphology, size, and crystalline phase) that allow modulating the photocatalytic response of titania material can be tuned simultaneously. This control has allowed an advance in the properties of the material, managing to increase the photoresponse in a short time.}, keywords = {anatase, morphology, nanocrystalline nanoparticles, organic particle-size, phase, photocatalysis, pollutants, rutile size solid-state synthesis, tio2 tio2, titanium-oxides}, pubstate = {published}, tppubtype = {article} } A solid-state phase control of TiO2 by the use of different macromolecular complex precursors is reported for the first time. During the formation of TiO2 nanoparticles, chitosan and poly(styrene-co-4-vinylpyridine) polymers can act as solid-state template producing areas after carbonization, where the TiO2 nucleates. It seems that the location of metal centers through the polymeric chain (i.e., the distance between the metal centers) strongly influences the morphology and particle size of the photocatalyst. To demonstrate the application value of our different TiO2 structures, the photocatalytic behavior was explored. The efficient photocatalytic decoloration of methylene blue on different polymorphic forms of nanostructured TiO2 is confirmed. The best photocatalyst achieved a 98% discoloration rate in only 25 min when the pH of the solution was 9.5, improving the efficiency of the standard photocatalyst Degussa P25 without the addition of other phases or dopants. The novelty of the present work is that, by means of an appropriate synthesis, the three main factors (morphology, size, and crystalline phase) that allow modulating the photocatalytic response of titania material can be tuned simultaneously. This control has allowed an advance in the properties of the material, managing to increase the photoresponse in a short time. |
Morales, R G E; Toro, R; Morales, L; Leiva, M A Landfill Fire and Airborne Aerosols in a Large City: Lessons Learned and Future Needs Artículo de revista Air Quality Atmosphere and Health, 11 (1), pp. 111-121, 2018, ISSN: 1873-9318. Resumen | Enlaces | BibTeX | Etiquetas: air-quality, atmospheric combustion, dioxins, emissions, environmental chemistry, fire, impact, landfill municipal particulatematter, pollution, precipitation, santiago, sites solid solid-waste, urban vegetation, waste @article{RN416, title = {Landfill Fire and Airborne Aerosols in a Large City: Lessons Learned and Future Needs}, author = {R.G.E. Morales and R. Toro and L. Morales and M.A. Leiva}, url = {/brokenurl#<Go to ISI>://WOS:000422939300011}, doi = {10.1007/s11869-017-0522-8}, issn = {1873-9318}, year = {2018}, date = {2018-01-01}, journal = {Air Quality Atmosphere and Health}, volume = {11}, number = {1}, pages = {111-121}, abstract = {Landfill fires are relatively frequent incidents that can result in severe environmental impacts. On the morning of January 15, 2016, a fire occurred at the Santa Marta landfill (Lf) in the metropolitan area of Santiago (SMA), Chile. The fire triggered public alarm. In the present work, the impact of the landfill fire on the air quality of the SMA and the possible impacts on human health are analyzed. According to the information collected, the fire began after a collapse in the landfill on January 15, 2016. The fire could not be controlled by the Lf operating company, and authorities acted late in responding. The results revealed that at the focal point of the fire, particulate matter with an aerodynamic diameter smaller than 2.5 mu m (PM2.5) reached concentration levels on the order of 1000 mu g m(-3). Three days after the start of the fire, hourly PM2.5 concentration levels above 200 mu g m(-3) were recorded, at a distance approximately 20 km northeast of where the fire occurred. The PM2.5 concentration levels recommended for the protection of the health of vulnerable persons were subsequently exceeded. These results suggest that a preventive measure should have been the evacuation of the most pollution-sensitive population. An inappropriate management of the emergency was demonstrated. Legislation should be improved by stipulating which sanitary Lfs should be equipped with firefighting equipment. Territorial planning should be improved by considering geographic and meteorological aspects.}, keywords = {air-quality, atmospheric combustion, dioxins, emissions, environmental chemistry, fire, impact, landfill municipal particulatematter, pollution, precipitation, santiago, sites solid solid-waste, urban vegetation, waste}, pubstate = {published}, tppubtype = {article} } Landfill fires are relatively frequent incidents that can result in severe environmental impacts. On the morning of January 15, 2016, a fire occurred at the Santa Marta landfill (Lf) in the metropolitan area of Santiago (SMA), Chile. The fire triggered public alarm. In the present work, the impact of the landfill fire on the air quality of the SMA and the possible impacts on human health are analyzed. According to the information collected, the fire began after a collapse in the landfill on January 15, 2016. The fire could not be controlled by the Lf operating company, and authorities acted late in responding. The results revealed that at the focal point of the fire, particulate matter with an aerodynamic diameter smaller than 2.5 mu m (PM2.5) reached concentration levels on the order of 1000 mu g m(-3). Three days after the start of the fire, hourly PM2.5 concentration levels above 200 mu g m(-3) were recorded, at a distance approximately 20 km northeast of where the fire occurred. The PM2.5 concentration levels recommended for the protection of the health of vulnerable persons were subsequently exceeded. These results suggest that a preventive measure should have been the evacuation of the most pollution-sensitive population. An inappropriate management of the emergency was demonstrated. Legislation should be improved by stipulating which sanitary Lfs should be equipped with firefighting equipment. Territorial planning should be improved by considering geographic and meteorological aspects. |
Gomez-Jeria, J S; Clavijo, E; Gutierrez, S An Infrared, Sem and Xrf Study of the Paper of a 1588 Spanish Book Artículo de revista Research Journal of Pharmaceutical Biological and Chemical Sciences, 9 (4), pp. 1581-1590, 2018, ISSN: 0975-8585. Resumen | Enlaces | BibTeX | Etiquetas: alum, analysis, archeology, cellulose, conservation, ft-ir gelatin, infrared margins paper postage potassium rags, sem, spain, spectra, spectroscopy, stamps, xrf @article{RN414, title = {An Infrared, Sem and Xrf Study of the Paper of a 1588 Spanish Book}, author = { J.S. Gomez-Jeria and E. Clavijo and S. Gutierrez}, url = {/brokenurl#<Go to ISI>://WOS:000438848100213}, issn = {0975-8585}, year = {2018}, date = {2018-01-01}, journal = {Research Journal of Pharmaceutical Biological and Chemical Sciences}, volume = {9}, number = {4}, pages = {1581-1590}, abstract = {An infrared, scanning electron microscopy and X-ray fluorescence study was performed on the Spanish book entitled Treated of the True and False Prophecy printed in Segovia during 1588. Three small samples were taken from the margins of three pages. Two of them belong to the original book while the third one is from a page added later during the binding of the book. The first result is that the paper is contaminated with numerous metallic elements. The distribution of these contaminants in the three samples suggests that this process began after the binding of the book. The carbonate moiety of the calcium carbonate seems to have disappeared with the passing of time transformed in carbon dioxide. Al, K and S, components of potassium alum are detected by SEM and XRF analyses. Gelatin seems to be present because some IR bands of proline suggest that. There is an unsolved problem with some IR bands because of the fact that they can be ascribed to two different entities.}, keywords = {alum, analysis, archeology, cellulose, conservation, ft-ir gelatin, infrared margins paper postage potassium rags, sem, spain, spectra, spectroscopy, stamps, xrf}, pubstate = {published}, tppubtype = {article} } An infrared, scanning electron microscopy and X-ray fluorescence study was performed on the Spanish book entitled Treated of the True and False Prophecy printed in Segovia during 1588. Three small samples were taken from the margins of three pages. Two of them belong to the original book while the third one is from a page added later during the binding of the book. The first result is that the paper is contaminated with numerous metallic elements. The distribution of these contaminants in the three samples suggests that this process began after the binding of the book. The carbonate moiety of the calcium carbonate seems to have disappeared with the passing of time transformed in carbon dioxide. Al, K and S, components of potassium alum are detected by SEM and XRF analyses. Gelatin seems to be present because some IR bands of proline suggest that. There is an unsolved problem with some IR bands because of the fact that they can be ascribed to two different entities. |
Publicaciones 2011-2020
