2021 |
Ogalde, J P; Korpisaari, A; Riera-Soto, C; Arriaza, B; Paipa, C; Leyton, P; Campos-Vallette, M; Lara, N; Chacama, J Archaeometric Analysis of Ceramic Production in Tiwanaku State (C.500–1000 Ce): An Exploratory Study Artículo de revista Archaeometry, 63 (1), pp. 53-67, 2021, ISSN: 0003-813X. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN57b, title = {Archaeometric Analysis of Ceramic Production in Tiwanaku State (C.500\textendash1000 Ce): An Exploratory Study}, author = {J P Ogalde and A Korpisaari and C Riera-Soto and B Arriaza and C Paipa and P Leyton and M Campos-Vallette and N Lara and J Chacama}, doi = {https://doi.org/10.1111/arcm.12597}, issn = {0003-813X}, year = {2021}, date = {2021-04-30}, journal = {Archaeometry}, volume = {63}, number = {1}, pages = {53-67}, abstract = {The chemical and mineralogical characterization of seven ceramic fragments produced within Tiwanaku state (c.500\textendash1000 ce) is reported. The instrumental techniques used included X-ray elemental and mineralogical chemical analysis, Raman spectroscopy, and scanning and light microscopy. The results indicate there are several clay types, although they show similarities, such as the use of a plant-based temper. The red colour of the decoration is hematite, and manganese oxides such as jacobsite are present in the black. The white colour is a mixture of gypsum and clay, and the orange is a mixture of hematite and clay. The use of colours, the quality of the clays and the temperatures reached during pottery firing point to expertise in ceramic production and to complex decision-making processes. The multi-elemental archaeometric approach documented here could become an important tool to shed a light on ancient ceramic technology and the internal variance of Tiwanaku pottery.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The chemical and mineralogical characterization of seven ceramic fragments produced within Tiwanaku state (c.500–1000 ce) is reported. The instrumental techniques used included X-ray elemental and mineralogical chemical analysis, Raman spectroscopy, and scanning and light microscopy. The results indicate there are several clay types, although they show similarities, such as the use of a plant-based temper. The red colour of the decoration is hematite, and manganese oxides such as jacobsite are present in the black. The white colour is a mixture of gypsum and clay, and the orange is a mixture of hematite and clay. The use of colours, the quality of the clays and the temperatures reached during pottery firing point to expertise in ceramic production and to complex decision-making processes. The multi-elemental archaeometric approach documented here could become an important tool to shed a light on ancient ceramic technology and the internal variance of Tiwanaku pottery. |
Donoso-González, O; Lodeiro, L; Aliaga, A E; Laguna-Bercero, M A; Bollo, S; Kogan, M J; Yutronic, N; Sierpe, R Functionalization of Gold Nanostars with Cationic Β-Cyclodextrin-Based Polymer for Drug Co-Loading and Sers Monitoring Artículo de revista Pharmaceutics, 13 (2), pp. 261, 2021, ISBN: 1999-4923. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN2_112, title = {Functionalization of Gold Nanostars with Cationic Β-Cyclodextrin-Based Polymer for Drug Co-Loading and Sers Monitoring}, author = {O Donoso-Gonz\'{a}lez and L Lodeiro and A.E. Aliaga and M A Laguna-Bercero and S Bollo and M J Kogan and N. Yutronic and R Sierpe}, url = {https://www.mdpi.com/1999-4923/13/2/261}, isbn = {1999-4923}, year = {2021}, date = {2021-04-01}, journal = {Pharmaceutics}, volume = {13}, number = {2}, pages = {261}, abstract = {Gold nanostars (AuNSs) exhibit modulated plasmon resonance and have a high SERS enhancement factor. However, their low colloidal stability limits their biomedical application as a nanomaterial. Cationic β-cyclodextrin-based polymer (CCD/P) has low cytotoxicity, can load and transport drugs more efficiently than the corresponding monomeric form, and has an appropriate cationic group to stabilize gold nanoparticles. In this work, we functionalized AuNSs with CCD/P to load phenylethylamine (PhEA) and piperine (PIP) and evaluated SERS-based applications of the products. PhEA and PIP were included in the polymer and used to functionalize AuNSs, forming a new AuNS-CCD/P-PhEA-PIP nanosystem. The system was characterized by UV\textendashVIS, IR, and NMR spectroscopy, TGA, SPR, DLS, zeta potential analysis, FE-SEM, and TEM. Additionally, Raman optical activity, SERS analysis and complementary theoretical studies were used for characterization. Minor adjustments increased the colloidal stability of AuNSs. The loading capacity of the CCD/P with PhEA-PIP was 95 ± 7%. The physicochemical parameters of the AuNS-CCD/P-PhEA-PIP system, such as size and Z potential, are suitable for potential biomedical applications Raman and SERS studies were used to monitor PhEA and PIP loading and their preferential orientation upon interaction with the surface of AuNSs. This unique nanomaterial could be used for simultaneous drug loading and SERS-based detection. }, keywords = {}, pubstate = {published}, tppubtype = {article} } Gold nanostars (AuNSs) exhibit modulated plasmon resonance and have a high SERS enhancement factor. However, their low colloidal stability limits their biomedical application as a nanomaterial. Cationic β-cyclodextrin-based polymer (CCD/P) has low cytotoxicity, can load and transport drugs more efficiently than the corresponding monomeric form, and has an appropriate cationic group to stabilize gold nanoparticles. In this work, we functionalized AuNSs with CCD/P to load phenylethylamine (PhEA) and piperine (PIP) and evaluated SERS-based applications of the products. PhEA and PIP were included in the polymer and used to functionalize AuNSs, forming a new AuNS-CCD/P-PhEA-PIP nanosystem. The system was characterized by UV–VIS, IR, and NMR spectroscopy, TGA, SPR, DLS, zeta potential analysis, FE-SEM, and TEM. Additionally, Raman optical activity, SERS analysis and complementary theoretical studies were used for characterization. Minor adjustments increased the colloidal stability of AuNSs. The loading capacity of the CCD/P with PhEA-PIP was 95 ± 7%. The physicochemical parameters of the AuNS-CCD/P-PhEA-PIP system, such as size and Z potential, are suitable for potential biomedical applications Raman and SERS studies were used to monitor PhEA and PIP loading and their preferential orientation upon interaction with the surface of AuNSs. This unique nanomaterial could be used for simultaneous drug loading and SERS-based detection. |
Toro, R; Catalán, F; Urdanivia, F R; Rojas, J P; Manzano, C A; Seguel, R; Gallardo, L; Osses, M; Pantoja, N; Leiva, M A Air Pollution and Covid-19 Lockdown in a Large South American City: Santiago Metropolitan Area, Chile Artículo de revista Urban Climate, 36 , pp. 100803, 2021, ISSN: 2212-0955 . Resumen | Enlaces | BibTeX | Etiquetas: @article{RN50b, title = {Air Pollution and Covid-19 Lockdown in a Large South American City: Santiago Metropolitan Area, Chile}, author = {R. Toro and F Catal\'{a}n and F R Urdanivia and J P Rojas and C A Manzano and R Seguel and L Gallardo and M Osses and N Pantoja and M.A. Leiva}, url = {https://www.sciencedirect.com/science/article/pii/S221209552100033X}, doi = {https://doi.org/10.1016/j.uclim.2021.100803}, issn = {2212-0955 }, year = {2021}, date = {2021-03-01}, journal = {Urban Climate}, volume = {36}, pages = {100803}, abstract = {The implementation of confinement and physical distancing measures to restrict people's activities and transit in the midst of the COVID-19 pandemic allowed us to study how these measures affect the air quality in urban areas with high pollution rates, such as Santiago, Chile. A comparative study between the concentrations of PM10, PM2.5, NOx, CO, and O3 during the months of March to May 2020 and the corresponding concentrations during the same period in 2017\textendash2019 is presented. A combination of surface measurements from the air quality monitoring network of the city, remote satellite measurements, and simulations of traffic activity and road transport emissions allowed us to quantify the change in the average concentrations of each pollutant. Average relative changes of traffic emissions (between 61% and 68%) implied statistically significant concentrations reductions of 54%, 13%, and 11% for NOx, CO, and PM2.5, respectively, during the pandemic period compared to historical period. In contrast, the average concentration of O3 increased by 63% during 2020 compared to 2017\textendash2019. The nonlinear response observed in the pollution levels can be attributed to the changes in the vehicular emission patterns during the pandemic and to the role of other sources such as residential emissions or secondary PM.}, key = {Urban air quality COVID-19 lockdown Traffic emission rates}, keywords = {}, pubstate = {published}, tppubtype = {article} } The implementation of confinement and physical distancing measures to restrict people's activities and transit in the midst of the COVID-19 pandemic allowed us to study how these measures affect the air quality in urban areas with high pollution rates, such as Santiago, Chile. A comparative study between the concentrations of PM10, PM2.5, NOx, CO, and O3 during the months of March to May 2020 and the corresponding concentrations during the same period in 2017–2019 is presented. A combination of surface measurements from the air quality monitoring network of the city, remote satellite measurements, and simulations of traffic activity and road transport emissions allowed us to quantify the change in the average concentrations of each pollutant. Average relative changes of traffic emissions (between 61% and 68%) implied statistically significant concentrations reductions of 54%, 13%, and 11% for NOx, CO, and PM2.5, respectively, during the pandemic period compared to historical period. In contrast, the average concentration of O3 increased by 63% during 2020 compared to 2017–2019. The nonlinear response observed in the pollution levels can be attributed to the changes in the vehicular emission patterns during the pandemic and to the role of other sources such as residential emissions or secondary PM. |
Rojas, J P; Urdanivia, F R; Garay, R A; García, A J; Enciso, C; Medina, E A; Toro, R; Manzano, C A; Leiva, M A Effects of Covid-19 Pandemic Control Measures on Air Pollution in Lima Metropolitan Area, Peru in South America Artículo de revista Air Quality, Atmosphere & Health, 10.1007/s11869-021-00990-3 , 2021, ISSN: 1873-9326. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN49b, title = {Effects of Covid-19 Pandemic Control Measures on Air Pollution in Lima Metropolitan Area, Peru in South America}, author = {J P Rojas and F R Urdanivia and R A Garay and A J Garc\'{i}a and C Enciso and E A Medina and R. Toro and C A Manzano and M.A. Leiva}, url = {https://doi.org/10.1007/s11869-021-00990-3}, doi = {10.1007/s11869-021-00990-3}, issn = {1873-9326}, year = {2021}, date = {2021-02-04}, journal = {Air Quality, Atmosphere & Health}, volume = {10.1007/s11869-021-00990-3}, abstract = {The sanitary measures implemented to control and prevent an increase in infections due to the COVID-19 pandemic have produced an improvement in the air quality of many urban areas around the world. We assessed air quality during the COVID-19 pandemic for particulate matter (PM2.5 and PM10), NO2 and O3 in in metropolitan area of Lima, Peru between pre-lockdown period (February 1 and March 15 of 2020), historical period (March 16 to April 30 2017\textendash2019) and lockdown period (March 16 to April 30, 2020). The complete national lockdown that was implemented in Peru produced statistically significant reductions in the in-air pollutant (PM10 (-40% and -58%), PM2.5 (-31% and -43%) and NO2 (-46% and -48%)), as recorded by the by the ground-based air quality monitoring network throughout the metropolitan area, compared with the corresponding concentrations for the previous weeks and over the same period for 2017\textendash2019. Analysis of the spatial Distribution of satellite data also show decreases in the concentrations of PM10, PM2.5 and NO2 as a result of the containment measures and suspension of activities implemented by the Peruvian government. The concentrations of O3 significantly increased (11% and 170%) as a result of the decrease in the concentration of NO2, confirming that the study area is a hydrocarbon-limited system, as previously reported. The results obtained contribute to the assessment by the regulatory agencies of the possible strategies of control and monitoring of air pollution in the study area.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The sanitary measures implemented to control and prevent an increase in infections due to the COVID-19 pandemic have produced an improvement in the air quality of many urban areas around the world. We assessed air quality during the COVID-19 pandemic for particulate matter (PM2.5 and PM10), NO2 and O3 in in metropolitan area of Lima, Peru between pre-lockdown period (February 1 and March 15 of 2020), historical period (March 16 to April 30 2017–2019) and lockdown period (March 16 to April 30, 2020). The complete national lockdown that was implemented in Peru produced statistically significant reductions in the in-air pollutant (PM10 (-40% and -58%), PM2.5 (-31% and -43%) and NO2 (-46% and -48%)), as recorded by the by the ground-based air quality monitoring network throughout the metropolitan area, compared with the corresponding concentrations for the previous weeks and over the same period for 2017–2019. Analysis of the spatial Distribution of satellite data also show decreases in the concentrations of PM10, PM2.5 and NO2 as a result of the containment measures and suspension of activities implemented by the Peruvian government. The concentrations of O3 significantly increased (11% and 170%) as a result of the decrease in the concentration of NO2, confirming that the study area is a hydrocarbon-limited system, as previously reported. The results obtained contribute to the assessment by the regulatory agencies of the possible strategies of control and monitoring of air pollution in the study area. |
Muñoz-Gacitúa, D; Monroy-Cárdenas, M; Araya-Maturana, R; Weiss-Lopez, B Characterization of an Anionic Membrane Mimetic with Natural Phospholipid Content and Magnetic Orienting Capabilities Artículo de revista Journal of Molecular Liquids, 323 , pp. 114616, 2021, ISSN: 0167-7322. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN18l, title = {Characterization of an Anionic Membrane Mimetic with Natural Phospholipid Content and Magnetic Orienting Capabilities}, author = {D Mu\~{n}oz-Gacit\'{u}a and M Monroy-C\'{a}rdenas and R Araya-Maturana and B. Weiss-Lopez}, url = {https://www.sciencedirect.com/science/article/pii/S0167732220335972}, doi = {https://doi.org/10.1016/j.molliq.2020.114616}, issn = {0167-7322}, year = {2021}, date = {2021-02-01}, journal = {Journal of Molecular Liquids}, volume = {323}, pages = {114616}, abstract = {The cellular membrane is a highly complex and dynamical structure, with variable and inhomogeneous composition, which makes detailed structural studies a very difficult task. 2H-NMR has become one of the most useful tools for many of such studies, however this requires the use of simpler structures that behave as close as possible to the cellular membrane, i.e. membrane mimetics. In this article we present a new anionic nematic lyotropic liquid crystal, with an important content of a natural mixture of phospholipids isolated from soybean, which can be employed as membrane mimetic. The capability of the mesophase to spontaneously orient when exposed to an external magnetic field, enables it for studies about distribution, dynamics and mobility of mesophase components, as well as dissolved substrates, employing 2H-NMR. A 2H-NMR characterization of the mimetic is performed by using different deuterated probes. To validate its permeability properties as membrane, the permeating capability of Benzocaine and the inability of Levodopa to do so were tested. For an atomic detailed characterization of both, the new mimetic and the process of crossing the interface, we also present a molecular dynamics simulation calibrated to reproduce experimental 2H-NMR results.}, key = {Membrane mimetic H-RMN Molecular dynamics}, keywords = {}, pubstate = {published}, tppubtype = {article} } The cellular membrane is a highly complex and dynamical structure, with variable and inhomogeneous composition, which makes detailed structural studies a very difficult task. 2H-NMR has become one of the most useful tools for many of such studies, however this requires the use of simpler structures that behave as close as possible to the cellular membrane, i.e. membrane mimetics. In this article we present a new anionic nematic lyotropic liquid crystal, with an important content of a natural mixture of phospholipids isolated from soybean, which can be employed as membrane mimetic. The capability of the mesophase to spontaneously orient when exposed to an external magnetic field, enables it for studies about distribution, dynamics and mobility of mesophase components, as well as dissolved substrates, employing 2H-NMR. A 2H-NMR characterization of the mimetic is performed by using different deuterated probes. To validate its permeability properties as membrane, the permeating capability of Benzocaine and the inability of Levodopa to do so were tested. For an atomic detailed characterization of both, the new mimetic and the process of crossing the interface, we also present a molecular dynamics simulation calibrated to reproduce experimental 2H-NMR results. |
Chibwe, L; Muir, D C G; Gopalapillai, Y; Shang, D; Kirk, J L; Manzano, C A; Atkinson, B; Wang, X; Teixeira, C Long-Term Spatial and Temporal Trends, and Source Apportionment of Polycyclic Aromatic Compounds in the Athabasca Oil Sands Region Artículo de revista Environmental Pollution, 268 , pp. 115351, 2021, ISSN: 0269-7491. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN37k, title = {Long-Term Spatial and Temporal Trends, and Source Apportionment of Polycyclic Aromatic Compounds in the Athabasca Oil Sands Region}, author = {L Chibwe and D C G Muir and Y Gopalapillai and D Shang and J L Kirk and C A Manzano and B Atkinson and X Wang and C Teixeira}, url = {https://www.sciencedirect.com/science/article/pii/S0269749120360395}, doi = {https://doi.org/10.1016/j.envpol.2020.115351}, issn = {0269-7491}, year = {2021}, date = {2021-01-01}, journal = {Environmental Pollution}, volume = {268}, pages = {115351}, abstract = {We investigated the spatio-temporal trends of polycyclic aromatic compounds (PACs) deposition in the Athabasca Oil Sands Region (AOSR) between 2008 and 2017, and applied source apportionment tools to assess sources using snowpacks. Estimated PAC mass deposition was significantly correlated with crude oil production (R2 = 0.48, p = 0.03), and increased between 2008 and 2017. Loadings of alkylated PACs c1-, c2-fluorenes/pyrenes and c1-, c3-benzo[a]anthracenes/chrysenes/triphenylenes significantly increased at mid-field sites (25\textendash50 km from central industrial reference site, AR6) (Mann-Kendall, p < 0.05) reflecting physical expansion of the AOSR. The distance from emission sources was important in the deposition of PACs, including the distance from AR6 (R2 = 0.69\textendash0.91), nearest petcoke storage (R2 = 0.77\textendash0.88), 0.89) and upgrader stack (R2 = 0.56\textendash0.61). Source apportionment PAC distribution profiles of the source materials (petcokes, oil sand ores, road dust) did not show unique matching profiles with the snowpacks. However, the minimal presence of retene in petcokes and an abundance of benzo[ghi]fluoranthene in road dust was observed, and suggests potential for these compounds as chemical markers in distinguishing sources. Furthermore, correlations between PACs and selected metal(loid)s in the AOSR snowpacks were assessed to infer potential common sources. Significant positive (p < 0.05) correlations between metal(loid)s enriched in bitumen (vanadium, molybdenum, nickel) and PACs, at near to mid-field (0\textendash50 km from AR6) sites suggests common sources or similar transfer and fate processes. The results of our study convey data necessary for monitoring studies in the constantly developing AOSR, advance our knowledge of PACs profiles in source materials (including the much less studied alkylated PACs and dibenzothiophenes), which will be valuable for other studies related to oil pollution, urban run-off and forest fires. PACs mass deposition increasing between 2008 and 2017 coincident with crude oil production, and retene and benzo[ghi]fluoranthene show potential in distinguishing AOSR sources.}, key = {PACs Athabasca Atmospheric deposition}, keywords = {}, pubstate = {published}, tppubtype = {article} } We investigated the spatio-temporal trends of polycyclic aromatic compounds (PACs) deposition in the Athabasca Oil Sands Region (AOSR) between 2008 and 2017, and applied source apportionment tools to assess sources using snowpacks. Estimated PAC mass deposition was significantly correlated with crude oil production (R2 = 0.48, p = 0.03), and increased between 2008 and 2017. Loadings of alkylated PACs c1-, c2-fluorenes/pyrenes and c1-, c3-benzo[a]anthracenes/chrysenes/triphenylenes significantly increased at mid-field sites (25–50 km from central industrial reference site, AR6) (Mann-Kendall, p < 0.05) reflecting physical expansion of the AOSR. The distance from emission sources was important in the deposition of PACs, including the distance from AR6 (R2 = 0.69–0.91), nearest petcoke storage (R2 = 0.77–0.88), 0.89) and upgrader stack (R2 = 0.56–0.61). Source apportionment PAC distribution profiles of the source materials (petcokes, oil sand ores, road dust) did not show unique matching profiles with the snowpacks. However, the minimal presence of retene in petcokes and an abundance of benzo[ghi]fluoranthene in road dust was observed, and suggests potential for these compounds as chemical markers in distinguishing sources. Furthermore, correlations between PACs and selected metal(loid)s in the AOSR snowpacks were assessed to infer potential common sources. Significant positive (p < 0.05) correlations between metal(loid)s enriched in bitumen (vanadium, molybdenum, nickel) and PACs, at near to mid-field (0–50 km from AR6) sites suggests common sources or similar transfer and fate processes. The results of our study convey data necessary for monitoring studies in the constantly developing AOSR, advance our knowledge of PACs profiles in source materials (including the much less studied alkylated PACs and dibenzothiophenes), which will be valuable for other studies related to oil pollution, urban run-off and forest fires. PACs mass deposition increasing between 2008 and 2017 coincident with crude oil production, and retene and benzo[ghi]fluoranthene show potential in distinguishing AOSR sources. |
Manzano, C A; Jácome, M; Syn, T; Molina, C; Toro, R; Leiva, M A Local Air Quality Issues and Research Priorities through the Lenses of Chilean Experts: An Ontological Analysis Artículo de revista Integrated Environmental Assessment and Management, 17 (1), pp. 273-281, 2021, ISSN: 1551-3777 . Resumen | Enlaces | BibTeX | Etiquetas: @article{RN48b, title = {Local Air Quality Issues and Research Priorities through the Lenses of Chilean Experts: An Ontological Analysis}, author = {C A Manzano and M J\'{a}come and T Syn and C Molina and R. Toro and M.A. Leiva}, doi = {https://doi.org/10.1002/ieam.4320}, issn = {1551-3777 }, year = {2021}, date = {2021-01-01}, journal = {Integrated Environmental Assessment and Management}, volume = {17}, number = {1}, pages = {273-281}, abstract = {ABSTRACT Air pollution problems can be large, complex, and ill-structured. They can vary from location to location and combine many complex components: urban expansion, increasing vehicles and industrial emissions, biomass burning, geographic and meteorological conditions, cultural aspects, and economic effects. However, the existing research, accumulated knowledge, and local research priorities are spread over many disciplines and lack a systematic mapping to help manage and develop new strategies for researchers and policy makers. Ontological analysis can be used as a tool to capture this complexity through simple natural-language descriptions and a structured terminology. We describe the development of an ontological framework for ?Air Quality Management in Chile? and its application to evaluate the current state of the research. The process was based on focus groups and validated by a panel of multidisciplinary experts. We used the developed framework to highlight the topics that have been heavily emphasized, lightly emphasized, or overlooked in the Chilean research. The framework developed can help researchers, practitioners, and policy makers systematically navigate the domain and provide the opportunity to correct blind spots by enabling more informed hypotheses that deal with air quality issues at a national level. We believe that applying this same process to different countries will yield different results (due to differences in local knowledge and experience). The framework presented could be used to evaluate other important stakeholders (government, media, NGOs, etc.), which will provide a complete picture of how local societies deal with air quality issues at different levels. Additionally, local government institutions will benefit from this analysis by improving funding allocation and opening new research opportunities to improve the distribution of the local body of knowledge. Integr Environ Assess Manag 2021;17:273?281. ? 2020 SETAC}, key = {Air quality Chile Management Ontology Particulate matter}, keywords = {}, pubstate = {published}, tppubtype = {article} } ABSTRACT Air pollution problems can be large, complex, and ill-structured. They can vary from location to location and combine many complex components: urban expansion, increasing vehicles and industrial emissions, biomass burning, geographic and meteorological conditions, cultural aspects, and economic effects. However, the existing research, accumulated knowledge, and local research priorities are spread over many disciplines and lack a systematic mapping to help manage and develop new strategies for researchers and policy makers. Ontological analysis can be used as a tool to capture this complexity through simple natural-language descriptions and a structured terminology. We describe the development of an ontological framework for ?Air Quality Management in Chile? and its application to evaluate the current state of the research. The process was based on focus groups and validated by a panel of multidisciplinary experts. We used the developed framework to highlight the topics that have been heavily emphasized, lightly emphasized, or overlooked in the Chilean research. The framework developed can help researchers, practitioners, and policy makers systematically navigate the domain and provide the opportunity to correct blind spots by enabling more informed hypotheses that deal with air quality issues at a national level. We believe that applying this same process to different countries will yield different results (due to differences in local knowledge and experience). The framework presented could be used to evaluate other important stakeholders (government, media, NGOs, etc.), which will provide a complete picture of how local societies deal with air quality issues at different levels. Additionally, local government institutions will benefit from this analysis by improving funding allocation and opening new research opportunities to improve the distribution of the local body of knowledge. Integr Environ Assess Manag 2021;17:273?281. ? 2020 SETAC |
Alegría, M; Aliaga, J; Ballesteros, L; Sotomayor-Torres, C; González, G; Benavente, E Layered Nanocomposite 2d-Tio2 with Cu2o Nanoparticles as an Efficient Photocatalyst for 4-Chlorophenol Degradation and Hydrogen Evolution Artículo de revista Topics in Catalysis, 64 (1), pp. 167-180, 2021, ISSN: 1572-9028 . Resumen | Enlaces | BibTeX | Etiquetas: @article{RN12m, title = {Layered Nanocomposite 2d-Tio2 with Cu2o Nanoparticles as an Efficient Photocatalyst for 4-Chlorophenol Degradation and Hydrogen Evolution}, author = {M Alegr\'{i}a and J Aliaga and L Ballesteros and C Sotomayor-Torres and G Gonz\'{a}lez and E Benavente}, url = {https://doi.org/10.1007/s11244-020-01360-6}, doi = {10.1007/s11244-020-01360-6}, issn = {1572-9028 }, year = {2021}, date = {2021-01-01}, journal = {Topics in Catalysis}, volume = {64}, number = {1}, pages = {167-180}, abstract = {New composites formed by layered hybrid TiO2(stearic acid) (LHTiO2) and, Cu2O nanoparticles were studied as photocatalysts that extend the response range to light visible for the evolution of hydrogen and the degradation of 4-chlorophenol. The results revealed that LHTiO2/Cu2O exhibited a clearly improved photocatalytic degradation, about 5.6 times faster than pristine TiO2, and hydrogen evolution of about 2.7 times higher than the TiO2 anatase. The enhanced photocatalytic activity can be assigned to the properties of the two-dimensional morphology, in sheets-like arrangement of LHTiO2, benefitting from the high exposure of surface, with more active sites available to improve matching with the surfaces of the Cu2O nanocrystals and significant reduction of migration distances of photogenerated carriers. In the photocatalytic degradation, a mechanism Z-scheme is supported, and in the photocatalytic evolution of hydrogen a mechanism type II band alignment is indicated. Photocatalytic reuse tests showed that stability and catalytic activity of LHTiO2/Cu2O were maintained for three cycles. Photoelectrochemical evaluation were performed through measurements of the photocurrent response and electrochemical impedance.}, keywords = {}, pubstate = {published}, tppubtype = {article} } New composites formed by layered hybrid TiO2(stearic acid) (LHTiO2) and, Cu2O nanoparticles were studied as photocatalysts that extend the response range to light visible for the evolution of hydrogen and the degradation of 4-chlorophenol. The results revealed that LHTiO2/Cu2O exhibited a clearly improved photocatalytic degradation, about 5.6 times faster than pristine TiO2, and hydrogen evolution of about 2.7 times higher than the TiO2 anatase. The enhanced photocatalytic activity can be assigned to the properties of the two-dimensional morphology, in sheets-like arrangement of LHTiO2, benefitting from the high exposure of surface, with more active sites available to improve matching with the surfaces of the Cu2O nanocrystals and significant reduction of migration distances of photogenerated carriers. In the photocatalytic degradation, a mechanism Z-scheme is supported, and in the photocatalytic evolution of hydrogen a mechanism type II band alignment is indicated. Photocatalytic reuse tests showed that stability and catalytic activity of LHTiO2/Cu2O were maintained for three cycles. Photoelectrochemical evaluation were performed through measurements of the photocurrent response and electrochemical impedance. |
Andrade, C; Molina, C; Sánchez, L F; Manzano, C A; Toro, R; Leiva, M A Exploring the Oxidative Potential and Respiratory Deposition of Size-Segregated Particulate Matter at an Urban Site Artículo de revista Journal of South American Earth Sciences, 105 , pp. 102957, 2021, ISSN: 0895-9811 . Resumen | Enlaces | BibTeX | Etiquetas: @article{RN34j, title = {Exploring the Oxidative Potential and Respiratory Deposition of Size-Segregated Particulate Matter at an Urban Site}, author = {C Andrade and C Molina and L F S\'{a}nchez and C A Manzano and R. Toro and M.A. Leiva}, url = {https://www.sciencedirect.com/science/article/pii/S0895981120305009}, doi = {https://doi.org/10.1016/j.jsames.2020.102957}, issn = {0895-9811 }, year = {2021}, date = {2021-01-01}, journal = {Journal of South American Earth Sciences}, volume = {105}, pages = {102957}, abstract = {According to the current understanding, the adverse health effects of particulate matter (PM) are produced by oxidative stress processes. Hence, the oxidative potential (OP) can be used as an exposure metric for more accurate approaches to the health response to ambient PM. This work explores the relationship between respiratory deposition of size-segregated PM and OP in the city of Santiago, Chile. Size-segregated PM samples were collected at an urban site using a Micro-Orifice Uniform Deposit Impactor (MOUDI) sampler. Dithiothreitol (DTT) loss rates were measured in aqueous PM extracts to estimate the OP for each sample. Size-segregated OP showed a bi-modal distribution with a maximum centered in the accumulation mode (0.18\textendash3.2 μm) and other in the coarse mode (3.2\textendash18 μm). The magnitude of the OP estimated in the accumulation mode was 2.9 ± 0.8 and 2.3 ± 0.6 times the magnitude of the OP estimated in the coarse and quasi-ultrafine mode, respectively. Respiratory deposition calculations indicated that PM3.2 (with diameter less than 3.2 μm) dominated the OP lung deposition with contributions ranging from 65 to 94% in different areas of the human respiratory tract. This was due to the deposition efficiency and greater surface area of these fractions that allowed more efficient adsorption of active redox chemical species. These results may account for the greater negative impact on the lung health of the fine fractions of PM. The characterization of the OP respiratory deposition related to different fractions of PM, can result in adequate metrics to evaluate human exposure to PM and its possible health impacts.}, key = {Particle size distribution Oxidative potential Lung deposition model Human exposure to PM}, keywords = {}, pubstate = {published}, tppubtype = {article} } According to the current understanding, the adverse health effects of particulate matter (PM) are produced by oxidative stress processes. Hence, the oxidative potential (OP) can be used as an exposure metric for more accurate approaches to the health response to ambient PM. This work explores the relationship between respiratory deposition of size-segregated PM and OP in the city of Santiago, Chile. Size-segregated PM samples were collected at an urban site using a Micro-Orifice Uniform Deposit Impactor (MOUDI) sampler. Dithiothreitol (DTT) loss rates were measured in aqueous PM extracts to estimate the OP for each sample. Size-segregated OP showed a bi-modal distribution with a maximum centered in the accumulation mode (0.18–3.2 μm) and other in the coarse mode (3.2–18 μm). The magnitude of the OP estimated in the accumulation mode was 2.9 ± 0.8 and 2.3 ± 0.6 times the magnitude of the OP estimated in the coarse and quasi-ultrafine mode, respectively. Respiratory deposition calculations indicated that PM3.2 (with diameter less than 3.2 μm) dominated the OP lung deposition with contributions ranging from 65 to 94% in different areas of the human respiratory tract. This was due to the deposition efficiency and greater surface area of these fractions that allowed more efficient adsorption of active redox chemical species. These results may account for the greater negative impact on the lung health of the fine fractions of PM. The characterization of the OP respiratory deposition related to different fractions of PM, can result in adequate metrics to evaluate human exposure to PM and its possible health impacts. |
Benavente, E; Aliaga, J; González, G Chapter 14 Vanadium Oxides in Photocatalysis, Including Bare Oxides and Vox-Based Organic–Inorganic Nanocomposites Capítulo de libro Vanadium Catalysis, 10.1039/9781839160882-00340 , pp. 340-373, The Royal Society of Chemistry, 2021, ISBN: 978-1-78801-857-9. @inbook{RN13j, title = {Chapter 14 Vanadium Oxides in Photocatalysis, Including Bare Oxides and Vox-Based Organic\textendashInorganic Nanocomposites}, author = {E Benavente and J Aliaga and G Gonz\'{a}lez}, url = {http://dx.doi.org/10.1039/9781839160882-00340}, doi = {10.1039/9781839160882-00340}, isbn = {978-1-78801-857-9}, year = {2021}, date = {2021-01-01}, booktitle = {Vanadium Catalysis}, volume = {10.1039/9781839160882-00340}, pages = {340-373}, publisher = {The Royal Society of Chemistry}, keywords = {}, pubstate = {published}, tppubtype = {inbook} } |
2020 |
Bolaños, K; Celis, F; Garrido, C; Campos-Vallette, M; Guzmán, F; Kogan, M J; Araya, E Adsorption of Bovine Serum Albumin on Gold Nanoprisms: Interaction and Effect of Nir Irradiation on Protein Corona Artículo de revista Journal of Materials Chemistry B, 8 (37), pp. 8644-8657, 2020, ISSN: 2050-750X. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN59b, title = {Adsorption of Bovine Serum Albumin on Gold Nanoprisms: Interaction and Effect of Nir Irradiation on Protein Corona}, author = {K Bola\~{n}os and F Celis and C Garrido and M Campos-Vallette and F Guzm\'{a}n and M J Kogan and E Araya}, doi = {10.1039/D0TB01246G}, issn = {2050-750X}, year = {2020}, date = {2020-12-31}, journal = {Journal of Materials Chemistry B}, volume = {8}, number = {37}, pages = {8644-8657}, abstract = {Because of their photothermal properties, gold nanoparticles (AuNPs) have gained attention regarding their use in drug delivery and therapeutic applications. In this sense, it is interesting to consider their interactions with biologically available proteins, such as serum albumin, as well as the effects of irradiation and photothermal conversion on the protein structure that can lead to a loss of function or generate an immune response. Gold nanoprisms (AuNPrs) have gained interest due to their low toxicity, ease of synthesis, and excellent stability, promoting their use in bioapplications such as surface-enhanced Raman spectroscopy (SERS), drug delivery, and photothermal therapy. The interaction between AuNPrs, with plasmon bands centred in the near-infrared region (NIR), and bovine serum albumin (BSA) has not been explored yet. UV-Vis spectroscopy, dynamic light scattering (DLS) and fluorescence spectroscopy were used to study the interaction between AuNPrs and BSA in addition to estimation of the adsorption rate and kinetic and thermodynamic parameters (K, ΔH°, ΔG°, ΔS°, and Ea) using adsorption isotherms and Langmuir and Freundlich models. The results suggest spontaneous cooperative binding in multilayer adsorption, achieved by the chemisorption of BSA on the AuNPr surface through the S\textendashAu interaction, as confirmed by Raman spectroscopy. On the other hand, the photothermal conversion efficiency (PE) of the coated nanoparticles after NIR irradiation was assessed, resulting in a slight decrease in the PE of BSA coated on AuNPrs in comparison with that of noncapped nanoparticles. The effect of the irradiation on the protein conformation of capped nanoparticles was also assessed; circular dichroism showed BSA unfolding upon interaction with AuNPrs, with a decrease in the α-helix and β-sheet contents, as well as an increase in random coil conformations. Changes in the Raman spectrum suggest a modification of the disposition of the protein residues exposed to the gold surface after NIR irradiation; but at the secondary structure level, no relevant changes were observed. This provides possibilities for the use of NPs\textendashBSA for bioapplications based on the photothermal effect promoted by laser irradiation, since the biological identity of the protein is preserved after NIR irradiation.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Because of their photothermal properties, gold nanoparticles (AuNPs) have gained attention regarding their use in drug delivery and therapeutic applications. In this sense, it is interesting to consider their interactions with biologically available proteins, such as serum albumin, as well as the effects of irradiation and photothermal conversion on the protein structure that can lead to a loss of function or generate an immune response. Gold nanoprisms (AuNPrs) have gained interest due to their low toxicity, ease of synthesis, and excellent stability, promoting their use in bioapplications such as surface-enhanced Raman spectroscopy (SERS), drug delivery, and photothermal therapy. The interaction between AuNPrs, with plasmon bands centred in the near-infrared region (NIR), and bovine serum albumin (BSA) has not been explored yet. UV-Vis spectroscopy, dynamic light scattering (DLS) and fluorescence spectroscopy were used to study the interaction between AuNPrs and BSA in addition to estimation of the adsorption rate and kinetic and thermodynamic parameters (K, ΔH°, ΔG°, ΔS°, and Ea) using adsorption isotherms and Langmuir and Freundlich models. The results suggest spontaneous cooperative binding in multilayer adsorption, achieved by the chemisorption of BSA on the AuNPr surface through the S–Au interaction, as confirmed by Raman spectroscopy. On the other hand, the photothermal conversion efficiency (PE) of the coated nanoparticles after NIR irradiation was assessed, resulting in a slight decrease in the PE of BSA coated on AuNPrs in comparison with that of noncapped nanoparticles. The effect of the irradiation on the protein conformation of capped nanoparticles was also assessed; circular dichroism showed BSA unfolding upon interaction with AuNPrs, with a decrease in the α-helix and β-sheet contents, as well as an increase in random coil conformations. Changes in the Raman spectrum suggest a modification of the disposition of the protein residues exposed to the gold surface after NIR irradiation; but at the secondary structure level, no relevant changes were observed. This provides possibilities for the use of NPs–BSA for bioapplications based on the photothermal effect promoted by laser irradiation, since the biological identity of the protein is preserved after NIR irradiation. |
Becerra-Ruiz, M; Galdámez, A; Modak, B; Vilches-Herrera, M Diastereoselective Synthesis of Spirodihydrobenzofuran Analogues of the Natural Product Filifolinol Artículo de revista ChemistrySelect, 5 (48), pp. 15175-15179, 2020, ISSN: 2365-6549 . Resumen | Enlaces | BibTeX | Etiquetas: @article{RN15l, title = {Diastereoselective Synthesis of Spirodihydrobenzofuran Analogues of the Natural Product Filifolinol}, author = {M Becerra-Ruiz and A. Gald\'{a}mez and B Modak and M. Vilches-Herrera}, doi = {https://doi.org/10.1002/slct.202003580}, issn = {2365-6549 }, year = {2020}, date = {2020-12-30}, journal = {ChemistrySelect}, volume = {5}, number = {48}, pages = {15175-15179}, abstract = {Abstract Filifolinol is a natural occurring spirodihydrobenzofuran isolated from the resinous exudates of Heliotropium filifolium, a Chilean endemic shrub. Filifolinol and some of its derivatives have shown interesting biological activities against pathogens that attack salmonid species. Whereas the synthesis of spirodihydrobenzofurans has been limited to the use of an ortho allylphenol unit herein we report a different approach based on a C?H activation/C?O cyclization reaction for the synthesis of analogues of Filifolinol. Moreover, a diastereoselective approach was developed using the different facial preference of hydride species and organolithium compounds towards cyclic ketones.}, key = {diastereoselective synthesis C−H activation fish immunostimulant spiro compounds}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract Filifolinol is a natural occurring spirodihydrobenzofuran isolated from the resinous exudates of Heliotropium filifolium, a Chilean endemic shrub. Filifolinol and some of its derivatives have shown interesting biological activities against pathogens that attack salmonid species. Whereas the synthesis of spirodihydrobenzofurans has been limited to the use of an ortho allylphenol unit herein we report a different approach based on a C?H activation/C?O cyclization reaction for the synthesis of analogues of Filifolinol. Moreover, a diastereoselective approach was developed using the different facial preference of hydride species and organolithium compounds towards cyclic ketones. |
Ormazábal-Toledo, R; Contreras, R Quantum Mechanical and Molecular Dynamic Approaches to Describe Solvation Effects by Neoteric Solvents Artículo de revista Current Opinion in Green and Sustainable Chemistry, 26 , pp. 100395, 2020, ISSN: 2452-2236 year = 2020. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN54b, title = {Quantum Mechanical and Molecular Dynamic Approaches to Describe Solvation Effects by Neoteric Solvents}, author = {R Ormaz\'{a}bal-Toledo and R. Contreras}, url = {https://www.sciencedirect.com/science/article/pii/S2452223620300924}, doi = {https://doi.org/10.1016/j.cogsc.2020.100395}, issn = {2452-2236 year = 2020}, year = {2020}, date = {2020-12-01}, journal = {Current Opinion in Green and Sustainable Chemistry}, volume = {26}, pages = {100395}, abstract = {This review deals with the problem of designing safer solvents for chemical transformation and chemical processes. These materials generically defined as neoteric solvents include the well known ionic liquids (ILs) and more recently, deep eutectic solvents (DESs). Super critical fluids also pertain to this class, but we will restrict our review to the former, IL and DES. The main object of this study is the description of properties of these solvents at a molecular level. Both IL and DES share a huge combinatorial flexibility leading to a formidable number of new solvents that can be prepared; and it is in this line that theory may help. This is because most of the binding properties to a wide variety of solutes may conveniently be described in terms of the electronic structure of matter, using quantum mechanical models, classical molecular dynamics and ab-initio molecular dynamics. The theoretical approach helps in the task of identifying and predicting optimal structures for specific applications.}, keywords = {}, pubstate = {published}, tppubtype = {article} } This review deals with the problem of designing safer solvents for chemical transformation and chemical processes. These materials generically defined as neoteric solvents include the well known ionic liquids (ILs) and more recently, deep eutectic solvents (DESs). Super critical fluids also pertain to this class, but we will restrict our review to the former, IL and DES. The main object of this study is the description of properties of these solvents at a molecular level. Both IL and DES share a huge combinatorial flexibility leading to a formidable number of new solvents that can be prepared; and it is in this line that theory may help. This is because most of the binding properties to a wide variety of solutes may conveniently be described in terms of the electronic structure of matter, using quantum mechanical models, classical molecular dynamics and ab-initio molecular dynamics. The theoretical approach helps in the task of identifying and predicting optimal structures for specific applications. |
Chibwe, L; Roberts, S; Shang, D; Yang, F; Manzano, C A; Wang, X; Kirk, J L; Muir, D C G A One-Century Sedimentary Record of N- and S-Polycyclic Aromatic Compounds in the Athabasca Oil Sands Region in Canada Artículo de revista Chemosphere, 260 , pp. 127641, 2020, ISSN: 0045-6535 . Resumen | Enlaces | BibTeX | Etiquetas: @article{RN38j, title = {A One-Century Sedimentary Record of N- and S-Polycyclic Aromatic Compounds in the Athabasca Oil Sands Region in Canada}, author = {L Chibwe and S Roberts and D Shang and F Yang and C A Manzano and X Wang and J L Kirk and D C G Muir}, url = {https://www.sciencedirect.com/science/article/pii/S0045653520318361}, doi = {https://doi.org/10.1016/j.chemosphere.2020.127641}, issn = {0045-6535 }, year = {2020}, date = {2020-12-01}, journal = {Chemosphere}, volume = {260}, pages = {127641}, abstract = {The atmospheric deposition of polycyclic aromatic compounds (PACs) is considered a major pathway to isolated lakes and bogs in the Athabasca oil sands region (AOSR), Canada. However, the suite of PACs measured has been limited. We report the detailed depositional history of nitrogen and sulphur heterocyclic PACs using a 210Pb dated sediment core (1914\textendash2015) near major developments in the AOSR. We observed (1) an exponential growth in the deposition of heterocyclic PACs to recent times with an average doubling time of 12 years, (2) significant breakpoints in PAC fluxes in the mid to late 1980s, and (3) a synchronous increase of PACs with crude oil production (r2 = 0.82, p = 0.001). NPACs were not detected prior to the 1960s in the sediment core studied, suggesting they may hold promise in serving as indicators for atmospheric PAC deposition of industrial origin. Furthermore, a change in heterocyclic PAC distribution profiles beginning in the 1970\textendash1980s, after the onset of mining, resembling a petcoke signature, was also observed. Significant positive correlations (p < 0.05) were observed between heterocyclic PACs, and several metal(loid)s, including priority pollutant elements, chromium and beryllium, and rare earth elements, cerium, lanthanum and yttrium (r2 > 0.75), suggesting the potential of a common source or similar transport and fate mechanisms. Significant negative or no correlations were observed between heterocyclic PACs and other metal(loid)s, including vanadium, total mercury and lead, possibly reflecting the impact of broader regulatory controls introduced in the mid-1970s on some metal(loids) but not on PACs, including the installation of electrostatic precipitators in major upgrader stacks.}, key = {Heterocyclic polycyclic aromatic compounds Sediment core Athabasca Oil sands}, keywords = {}, pubstate = {published}, tppubtype = {article} } The atmospheric deposition of polycyclic aromatic compounds (PACs) is considered a major pathway to isolated lakes and bogs in the Athabasca oil sands region (AOSR), Canada. However, the suite of PACs measured has been limited. We report the detailed depositional history of nitrogen and sulphur heterocyclic PACs using a 210Pb dated sediment core (1914–2015) near major developments in the AOSR. We observed (1) an exponential growth in the deposition of heterocyclic PACs to recent times with an average doubling time of 12 years, (2) significant breakpoints in PAC fluxes in the mid to late 1980s, and (3) a synchronous increase of PACs with crude oil production (r2 = 0.82, p = 0.001). NPACs were not detected prior to the 1960s in the sediment core studied, suggesting they may hold promise in serving as indicators for atmospheric PAC deposition of industrial origin. Furthermore, a change in heterocyclic PAC distribution profiles beginning in the 1970–1980s, after the onset of mining, resembling a petcoke signature, was also observed. Significant positive correlations (p < 0.05) were observed between heterocyclic PACs, and several metal(loid)s, including priority pollutant elements, chromium and beryllium, and rare earth elements, cerium, lanthanum and yttrium (r2 > 0.75), suggesting the potential of a common source or similar transport and fate mechanisms. Significant negative or no correlations were observed between heterocyclic PACs and other metal(loid)s, including vanadium, total mercury and lead, possibly reflecting the impact of broader regulatory controls introduced in the mid-1970s on some metal(loids) but not on PACs, including the installation of electrostatic precipitators in major upgrader stacks. |
Copaja, S; Tessada, R Seasonal and Spatial Variation of Trace Elements in Sediments of Three Chilean Basins Artículo de revista Journal of the Chilean Chemical Society, 65 , pp. 4737-4745, 2020, ISBN: 0717-9707. @article{RN19l, title = {Seasonal and Spatial Variation of Trace Elements in Sediments of Three Chilean Basins}, author = {S. Copaja and R Tessada}, url = {https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0717-97072020000104737&nrm=iso}, isbn = {0717-9707}, year = {2020}, date = {2020-11-30}, journal = {Journal of the Chilean Chemical Society}, volume = {65}, pages = {4737-4745}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Lodeiro, L; Barría-Cáceres, F; Jiménez, K; Contreras, R; Montero-Alejo, A L; Menéndez-Proupin, E Methodological Issues in First-Principle Calculations of Ch3nh3pbi3 Perovskite Surfaces: Quantum Confinement and Thermal Motion Artículo de revista ACS Omega, 5 (45), pp. 29477-29491, 2020, ISSN: 2470-1343. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN53b, title = {Methodological Issues in First-Principle Calculations of Ch3nh3pbi3 Perovskite Surfaces: Quantum Confinement and Thermal Motion}, author = {L Lodeiro and F Barr\'{i}a-C\'{a}ceres and K Jim\'{e}nez and R. Contreras and A L Montero-Alejo and E Men\'{e}ndez-Proupin}, doi = {10.1021/acsomega.0c04420}, issn = {2470-1343}, year = {2020}, date = {2020-11-17}, journal = {ACS Omega}, volume = {5}, number = {45}, pages = {29477-29491}, abstract = {Characterization and control of surfaces and interfaces are critical for photovoltaic and photocatalytic applications. In this work, we propose CH3NH3PbI3 (MAPI) perovskite slab models whose energy levels, free of quantum confinement, explicitly consider the spin\textendashorbit coupling and thermal motion. We detail methodological tools based on the density functional theory that allow achieving these models at an affordable computational cost, and analytical corrections are proposed to correct these effects in other systems. The electronic state energies with respect to the vacuum of the static MAPI surface models, terminated in PbI2 and MAI atomic layers, are in agreement with the experimental data. The PbI2-terminated slab has in-gap surface states, which are independent of the thickness of the slab and also of the orientation of the cation on the surface. The surface states are not useful for alignments in photovoltaic devices, while they could be useful for photocatalytic reactions. The energy levels calculated for the MAI-terminated surface coincide with the widely used values to estimate the MAPI alignment with the charge transport materials, i.e., −5.4 and −3.9 eV for valence band maximum and conduction band minimum, respectively. Our study offers these slab models to provide guidelines for optimal interface engineering.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Characterization and control of surfaces and interfaces are critical for photovoltaic and photocatalytic applications. In this work, we propose CH3NH3PbI3 (MAPI) perovskite slab models whose energy levels, free of quantum confinement, explicitly consider the spin–orbit coupling and thermal motion. We detail methodological tools based on the density functional theory that allow achieving these models at an affordable computational cost, and analytical corrections are proposed to correct these effects in other systems. The electronic state energies with respect to the vacuum of the static MAPI surface models, terminated in PbI2 and MAI atomic layers, are in agreement with the experimental data. The PbI2-terminated slab has in-gap surface states, which are independent of the thickness of the slab and also of the orientation of the cation on the surface. The surface states are not useful for alignments in photovoltaic devices, while they could be useful for photocatalytic reactions. The energy levels calculated for the MAI-terminated surface coincide with the widely used values to estimate the MAPI alignment with the charge transport materials, i.e., −5.4 and −3.9 eV for valence band maximum and conduction band minimum, respectively. Our study offers these slab models to provide guidelines for optimal interface engineering. |
Molina, C; Andrade, C; Manzano, C A; Toro, R; Verma, V; Leiva, M A Dithiothreitol-Based Oxidative Potential for Airborne Particulate Matter: An Estimation of the Associated Uncertainty Artículo de revista Environmental Science and Pollution Research, 27 (23), pp. 29672-29680, 2020, ISSN: 1614-7499. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN39l, title = {Dithiothreitol-Based Oxidative Potential for Airborne Particulate Matter: An Estimation of the Associated Uncertainty}, author = {C Molina and C Andrade and C A Manzano and R. Toro and V Verma and M.A. Leiva}, doi = {10.1007/s11356-020-09508-3}, issn = {1614-7499}, year = {2020}, date = {2020-08-01}, journal = {Environmental Science and Pollution Research}, volume = {27}, number = {23}, pages = {29672-29680}, abstract = {Oxidative stress is considered as one of the main mechanisms by which airborne particles produce adverse health effects. Several methods to estimate the oxidative potential (OP) of particulate matter (PM) have been proposed. Among them, the dithiothreitol (DTT) assay has gained popularity due to its simplicity and overall low implementation cost. Usually, the estimations of OPDTT are based on n-replicates of a set of samples and their associated standard deviation. However, interlaboratory comparisons of OPDTT can be difficult and lead to misinterpretations. This work presents an estimation of the total uncertainty for the OPDTT measurement of PM10 and PM2.5 samples collected in Santiago (Chile), based on recommendations by the Joint Committee for Guides in Metrology and Eurachem. The expanded uncertainty expressed as a percentage of the mass-normalized OPDTT measurements was 18.0% and 16.3% for PM10 and PM2.5 samples respectively. The dominating contributor to the total uncertainty was identified (i.e., DTT consumption rate, related to the regression and repeatability of experimental data), while the volumetric operations (i.e., pipettes) were also important. The results showed that, although the OP measured following the DTT assay has been successfully used to estimate the potential health impacts of airborne PM, uncertainty estimations must be considered before interpreting the results.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Oxidative stress is considered as one of the main mechanisms by which airborne particles produce adverse health effects. Several methods to estimate the oxidative potential (OP) of particulate matter (PM) have been proposed. Among them, the dithiothreitol (DTT) assay has gained popularity due to its simplicity and overall low implementation cost. Usually, the estimations of OPDTT are based on n-replicates of a set of samples and their associated standard deviation. However, interlaboratory comparisons of OPDTT can be difficult and lead to misinterpretations. This work presents an estimation of the total uncertainty for the OPDTT measurement of PM10 and PM2.5 samples collected in Santiago (Chile), based on recommendations by the Joint Committee for Guides in Metrology and Eurachem. The expanded uncertainty expressed as a percentage of the mass-normalized OPDTT measurements was 18.0% and 16.3% for PM10 and PM2.5 samples respectively. The dominating contributor to the total uncertainty was identified (i.e., DTT consumption rate, related to the regression and repeatability of experimental data), while the volumetric operations (i.e., pipettes) were also important. The results showed that, although the OP measured following the DTT assay has been successfully used to estimate the potential health impacts of airborne PM, uncertainty estimations must be considered before interpreting the results. |
Vilches-Herrera, M; Gallardo-Fuentes, S; Aravena-Opitz, M; Yáñez-Sánchez, M; Jiao, H; Holz, J; Börner, A; Lühr, S Reduction over Condensation of Carbonyl Compounds through a Transient Hemiaminal Intermediate Using Hydrazine Artículo de revista The Journal of Organic Chemistry, 85 (14), pp. 9213-9218, 2020, ISSN: 0022-3263. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN16k, title = {Reduction over Condensation of Carbonyl Compounds through a Transient Hemiaminal Intermediate Using Hydrazine}, author = {M. Vilches-Herrera and S Gallardo-Fuentes and M Aravena-Opitz and M Y\'{a}\~{n}ez-S\'{a}nchez and H Jiao and J Holz and A B\"{o}rner and S. L\"{u}hr}, doi = {10.1021/acs.joc.0c01212}, issn = {0022-3263}, year = {2020}, date = {2020-07-17}, journal = {The Journal of Organic Chemistry}, volume = {85}, number = {14}, pages = {9213-9218}, abstract = {Reduction of carbonyl moieties to the corresponding alcohol using simply hydrazine hydrate has been considerably unfeasible until now due to the well-known condensation reaction. However, herein, we report that using an excess of 20-fold equivalents, the reduction proceeds in excellent yields. 1H NMR study of the reaction and density functional theory (DFT) calculations indicate that the final fate of the hemiaminal intermediate is crucial to obtain the alcohol or the hydrazone.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Reduction of carbonyl moieties to the corresponding alcohol using simply hydrazine hydrate has been considerably unfeasible until now due to the well-known condensation reaction. However, herein, we report that using an excess of 20-fold equivalents, the reduction proceeds in excellent yields. 1H NMR study of the reaction and density functional theory (DFT) calculations indicate that the final fate of the hemiaminal intermediate is crucial to obtain the alcohol or the hydrazone. |
López, M L; Álvarez-Serrano, I; Galdámez, A; Rodríguez-Aguado, E; Rodríguez-Castellón, E; Saad, Y New Dielectric Anomalies in the a-Site Highly Deficient Naxnbo3 Electroceramics Artículo de revista Ceramics International, 46 (10, Part B), pp. 16770-16780, 2020, ISSN: 0272-8842. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN30m, title = {New Dielectric Anomalies in the a-Site Highly Deficient Naxnbo3 Electroceramics}, author = {M L L\'{o}pez and I \'{A}lvarez-Serrano and A Gald\'{a}mez and E Rodr\'{i}guez-Aguado and E Rodr\'{i}guez-Castell\'{o}n and Y Saad}, url = {https://www.sciencedirect.com/science/article/pii/S0272884220309019}, doi = {https://doi.org/10.1016/j.ceramint.2020.03.253}, issn = {0272-8842}, year = {2020}, date = {2020-07-01}, journal = {Ceramics International}, volume = {46}, number = {10, Part B}, pages = {16770-16780}, abstract = {Highly sodium deficient Na0.6NbO3 (NN) ceramics were prepared and characterized. Their mean structure could be described by a mixture of the predominant P polymorph (S.G. Pbma) and the Q phase (S.G. P21ma), at room temperature, as deduced from Rietveld refinements of Powder X-ray diffraction and Raman scattering data. Besides, microstructural and compositional heterogeneity was evidenced from HRTEM and XPS analyses. Dielectric measurements on this highly vacancies-containing NN material indicated a hysteretic transition taking place at ~12 and −18 °C on the heating and cooling regimes, respectively. This means a considerable shift to lower temperatures of the transition temperatures concerning the P/Q transformations previously described for the NaNbO3 material. At an intermediate frequency of 10 kHz, maximum permittivity and tangent loss values of ε' = 1250 and tgδ = 2 were obtained on heating, whereas lower values of ε' = 65 and tgδ = 0.04 were displayed on cooling regime. These anomalies were interpreted in terms of ferrolectric-antiferroelectric-paralectric phase-transitions implying a PTCR behavior within certain temperature range. This response, observed in this complex material for the first time, has interesting implications for the possible application of NN ceramics in sensing and dielectric materials fields.}, key = {Dielectrics Sodium niobate A-site vacancies PTCR}, keywords = {}, pubstate = {published}, tppubtype = {article} } Highly sodium deficient Na0.6NbO3 (NN) ceramics were prepared and characterized. Their mean structure could be described by a mixture of the predominant P polymorph (S.G. Pbma) and the Q phase (S.G. P21ma), at room temperature, as deduced from Rietveld refinements of Powder X-ray diffraction and Raman scattering data. Besides, microstructural and compositional heterogeneity was evidenced from HRTEM and XPS analyses. Dielectric measurements on this highly vacancies-containing NN material indicated a hysteretic transition taking place at ~12 and −18 °C on the heating and cooling regimes, respectively. This means a considerable shift to lower temperatures of the transition temperatures concerning the P/Q transformations previously described for the NaNbO3 material. At an intermediate frequency of 10 kHz, maximum permittivity and tangent loss values of ε' = 1250 and tgδ = 2 were obtained on heating, whereas lower values of ε' = 65 and tgδ = 0.04 were displayed on cooling regime. These anomalies were interpreted in terms of ferrolectric-antiferroelectric-paralectric phase-transitions implying a PTCR behavior within certain temperature range. This response, observed in this complex material for the first time, has interesting implications for the possible application of NN ceramics in sensing and dielectric materials fields. |
Copaja, S; Mauro, L; Vega-Retter, C; Véliz, D Adsorption-Desorption of Trace Elements in Sediments of the Maipo River Basin Artículo de revista Journal of the Chilean Chemical Society, 65 , pp. 4778-4783, 2020. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN22l, title = {Adsorption-Desorption of Trace Elements in Sediments of the Maipo River Basin}, author = {S. Copaja and L Mauro and C Vega-Retter and D V\'{e}liz}, url = {https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0717-97072020000204778&nrm=iso}, doi = {http://dx.doi.org/10.4067/S0717-97072020000204778 }, year = {2020}, date = {2020-06-30}, journal = {Journal of the Chilean Chemical Society}, volume = {65}, pages = {4778-4783}, abstract = {We studied the adsorption-desorption of Cu, Mn, Pb and Zn in Maipo river basin, one of the most perturbed rivers in Chile, and thus determined its tolerance to the addition of these metals into the sediments and the possibility of transferring the metals from the sediments to the water column. Sediments were sampled from six sites from the river basin and characterized by their pH, electrical conductivity, organic carbon, total organic carbon, water soluble phosphorus and texture. Batch sorption and kinetics experiments were conducted to obtain the retained amounts onto the sediment samples. The initial concentration of trace elements in the sediment was quantified by AAS. The metals were present in most of the sites. Sorption parameters such as Kd and Koc were determined. Metals were adsorbed in the sediment, with Mn showing the lowest affinity, Kd and Koc values and Freundlich constant (nf) support these results. Desorption less than 1% were observed for Cu, while Pb and Zn ranged from 0.6% to 6.8% and those for Mn ranged from 0% to 17.6% across sites. The tolerance of the Maipo River to metal adsorption in sediments was as follows: Pb> Cu> Zn >Mn. Desorption analysis showed that both Zn and Mn could be transferred from the sediment to the water column. The strongest correlation occurs between the pH and Kd-Pb, indicating that at higher pH values, the Pb adsorption was unfavorable, while the correlation was moderate for Cu, Mn and Zn. On the other hand, there are positive correlations between pairs of metals such as Mn-Cu, Zn-Cu, and Zn-Mn, indicating the competition of these metals for the adsorbent sites. The high concentration of Mn found in the sediment and the possibility of being transferred to the water column, due to its easy of desorption, suggest concern due to its potential risk to aquatic biota.}, keywords = {}, pubstate = {published}, tppubtype = {article} } We studied the adsorption-desorption of Cu, Mn, Pb and Zn in Maipo river basin, one of the most perturbed rivers in Chile, and thus determined its tolerance to the addition of these metals into the sediments and the possibility of transferring the metals from the sediments to the water column. Sediments were sampled from six sites from the river basin and characterized by their pH, electrical conductivity, organic carbon, total organic carbon, water soluble phosphorus and texture. Batch sorption and kinetics experiments were conducted to obtain the retained amounts onto the sediment samples. The initial concentration of trace elements in the sediment was quantified by AAS. The metals were present in most of the sites. Sorption parameters such as Kd and Koc were determined. Metals were adsorbed in the sediment, with Mn showing the lowest affinity, Kd and Koc values and Freundlich constant (nf) support these results. Desorption less than 1% were observed for Cu, while Pb and Zn ranged from 0.6% to 6.8% and those for Mn ranged from 0% to 17.6% across sites. The tolerance of the Maipo River to metal adsorption in sediments was as follows: Pb> Cu> Zn >Mn. Desorption analysis showed that both Zn and Mn could be transferred from the sediment to the water column. The strongest correlation occurs between the pH and Kd-Pb, indicating that at higher pH values, the Pb adsorption was unfavorable, while the correlation was moderate for Cu, Mn and Zn. On the other hand, there are positive correlations between pairs of metals such as Mn-Cu, Zn-Cu, and Zn-Mn, indicating the competition of these metals for the adsorbent sites. The high concentration of Mn found in the sediment and the possibility of being transferred to the water column, due to its easy of desorption, suggest concern due to its potential risk to aquatic biota. |
Mendizabal, F; Miranda-Rojas, S; Castro-Latorre, P Quantum Chemistry Simulation of the Electronic Properties in [Au(Nh3)2]No3 and [Au(Nch)2][Aucl4] Extended Unsupported Complexes Artículo de revista Molecular Simulation, 46 (7), pp. 521-529, 2020, ISSN: 0892-7022 . Resumen | Enlaces | BibTeX | Etiquetas: @article{RN26l, title = {Quantum Chemistry Simulation of the Electronic Properties in [Au(Nh3)2]No3 and [Au(Nch)2][Aucl4] Extended Unsupported Complexes}, author = {F. Mendizabal and S Miranda-Rojas and P Castro-Latorre}, doi = {10.1080/08927022.2020.1735634}, issn = {0892-7022 }, year = {2020}, date = {2020-05-02}, journal = {Molecular Simulation}, volume = {46}, number = {7}, pages = {521-529}, abstract = {ABSTRACTThe understanding of closed-shell interactions has become of tremendous relevance in the ever-growing field of supramolecular chemistry. Here, we present a theoretical study in which we characterised the intermolecular interactions between gold-based building blocks, namely ([Au(NH3)2]NO3)n (n?=?1,2,4,8) and ([Au(NCH)2][AuCl4])n (n?=?1,2). Due to the complex nature of these interactions, several methods were used such as the MP2, CCSD(T), PBE-D3, B3LYP-D3, and CAM-B3LYP-D3 (DFT-D3) levels. In all models were found closed-shell contacts among the gold atoms, interactions that resulted in being consistent with the presence of a high ionic contribution and a dispersion-type interaction. The absorption spectra of these models were calculated by the single excitation time-dependent-DFT (TD-DFT) method and CC2 levels, being the aurophilic interactions mainly responsible for the bands in both types of models. The theoretical models agree with the experimental results.}, keywords = {}, pubstate = {published}, tppubtype = {article} } ABSTRACTThe understanding of closed-shell interactions has become of tremendous relevance in the ever-growing field of supramolecular chemistry. Here, we present a theoretical study in which we characterised the intermolecular interactions between gold-based building blocks, namely ([Au(NH3)2]NO3)n (n?=?1,2,4,8) and ([Au(NCH)2][AuCl4])n (n?=?1,2). Due to the complex nature of these interactions, several methods were used such as the MP2, CCSD(T), PBE-D3, B3LYP-D3, and CAM-B3LYP-D3 (DFT-D3) levels. In all models were found closed-shell contacts among the gold atoms, interactions that resulted in being consistent with the presence of a high ionic contribution and a dispersion-type interaction. The absorption spectra of these models were calculated by the single excitation time-dependent-DFT (TD-DFT) method and CC2 levels, being the aurophilic interactions mainly responsible for the bands in both types of models. The theoretical models agree with the experimental results. |
Rodriguez, S; Pertino, M W; Arcos, C; Reichert, L; Echeverria, J; Simirgiotis, M; Borquez, J; Cornejo, A; Areche, C; Sepulveda, B Isolation, Gastroprotective Effects and Untargeted Metabolomics Analysis of Lycium Minutifolium J. Remy (Solanaceae) Artículo de revista Foods, 9 (5), pp. 565, 2020, ISBN: 2304-8158. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN5r, title = {Isolation, Gastroprotective Effects and Untargeted Metabolomics Analysis of Lycium Minutifolium J. Remy (Solanaceae)}, author = {S Rodriguez and M W Pertino and C Arcos and L Reichert and J Echeverria and M Simirgiotis and J Borquez and A Cornejo and C Areche and B Sepulveda}, url = {https://www.mdpi.com/2304-8158/9/5/565}, isbn = {2304-8158}, year = {2020}, date = {2020-04-30}, journal = {Foods}, volume = {9}, number = {5}, pages = {565}, abstract = {Lycium minutifolium J. Remy (Solanaceae) is commonly used as an infusion in traditional medicine to treat stomach pain, meteorism, intestinal disorders, stomach ailments, and other severe problems including prostate cancer and stomach cancer. From the EtOAc extract of L. minutifolium bark five known metabolites were isolated using chromatographic techniques. The gastroprotective effects of the EtOAc fraction and edible infusion extract of the bark were assayed on the hydrochloric acid (HCl)/EtOH induced gastric ulcer model in mice to support the traditional use of the plant. The EtOAc extract and the edible infusion showed gastroprotective effect at dose of 100 mg/kg reducing lesions by 31% and 64%, respectively. The gastroprotective action mechanisms of the edible infusion at a single oral dose of 100 mg/kg were evaluated suggesting that prostaglandins, sulfhydryl groups, and nitric oxide are involved in the mode of gastroprotective action. The UHPLC analysis coupled to high-resolution mass spectrometry of the edible infusion showed the presence of twenty-three compounds. Our results can support the gastroprotective properties of the edible infusion extract, and at least can validate in part, the ethnopharmacological uses of the plant}, keywords = {}, pubstate = {published}, tppubtype = {article} } Lycium minutifolium J. Remy (Solanaceae) is commonly used as an infusion in traditional medicine to treat stomach pain, meteorism, intestinal disorders, stomach ailments, and other severe problems including prostate cancer and stomach cancer. From the EtOAc extract of L. minutifolium bark five known metabolites were isolated using chromatographic techniques. The gastroprotective effects of the EtOAc fraction and edible infusion extract of the bark were assayed on the hydrochloric acid (HCl)/EtOH induced gastric ulcer model in mice to support the traditional use of the plant. The EtOAc extract and the edible infusion showed gastroprotective effect at dose of 100 mg/kg reducing lesions by 31% and 64%, respectively. The gastroprotective action mechanisms of the edible infusion at a single oral dose of 100 mg/kg were evaluated suggesting that prostaglandins, sulfhydryl groups, and nitric oxide are involved in the mode of gastroprotective action. The UHPLC analysis coupled to high-resolution mass spectrometry of the edible infusion showed the presence of twenty-three compounds. Our results can support the gastroprotective properties of the edible infusion extract, and at least can validate in part, the ethnopharmacological uses of the plant |
Celis, F; Tirapegui, C; García, M; Aracena, A; Aliaga, A E; Campos-Vallette, M Identification of Coexisting Indigo Species in an Ancient Green Thread Using Direct Plasmon-Enhanced Raman Spectroscopy Artículo de revista Journal of the Chilean Chemical Society, 65 , pp. 4798-4803, 2020, ISBN: 0717-9707. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN1_127, title = {Identification of Coexisting Indigo Species in an Ancient Green Thread Using Direct Plasmon-Enhanced Raman Spectroscopy}, author = {F Celis and C Tirapegui and M Garc\'{i}a and A Aracena and A.E. Aliaga and M Campos-Vallette}, url = {https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0717-97072020000204798&nrm=iso}, isbn = {0717-9707}, year = {2020}, date = {2020-04-30}, journal = {Journal of the Chilean Chemical Society}, volume = {65}, pages = {4798-4803}, abstract = {A green ancient thread sample from a Chilean mummy turban was analyzed by plasmon-enhanced Raman scattering spectroscopy using a direct drop-colloidal method. The enhanced-Raman signals in the sample are associated with biomolecules from the thread and two coexisting dyes, indigo and leuco-indigo. The presence of indigo (blue colour) was identified from its most characteristic vibrational bands. Leuco-indigo (yellow colour) was identified for the first time in an ancient textile; its SERS signals are coincident with the SERS bands of a synthesized leuco-indigo. The interconversion leuco-indigo to indigo was followed by UV-visible spectroscopy. Based on theoretical calculations it is proposed that the interconversion involves a π electron delocalization mainly around the NC-CN bridge. The mixture of both dyes (indigo and leuco-indigo) is the responsible for the green colour observed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } A green ancient thread sample from a Chilean mummy turban was analyzed by plasmon-enhanced Raman scattering spectroscopy using a direct drop-colloidal method. The enhanced-Raman signals in the sample are associated with biomolecules from the thread and two coexisting dyes, indigo and leuco-indigo. The presence of indigo (blue colour) was identified from its most characteristic vibrational bands. Leuco-indigo (yellow colour) was identified for the first time in an ancient textile; its SERS signals are coincident with the SERS bands of a synthesized leuco-indigo. The interconversion leuco-indigo to indigo was followed by UV-visible spectroscopy. Based on theoretical calculations it is proposed that the interconversion involves a π electron delocalization mainly around the NC-CN bridge. The mixture of both dyes (indigo and leuco-indigo) is the responsible for the green colour observed. |
Jara-Guajardo, P; Cabrera, P; Celis, F; Soler, M; Berlanga, I; Parra-Muñoz, N; Acosta, G; Albericio, F; Guzman, F; Campos, M; Alvarez, A; Morales-Zavala, F Gold Nanoparticles Mediate Improved Detection of Β-Amyloid Aggregates by Fluorescence Artículo de revista Nanomaterials, 10 (4), pp. 690, 2020, ISBN: 2079-4991. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN61b, title = {Gold Nanoparticles Mediate Improved Detection of Β-Amyloid Aggregates by Fluorescence}, author = {P Jara-Guajardo and P Cabrera and F Celis and M Soler and I Berlanga and N Parra-Mu\~{n}oz and G Acosta and F Albericio and F Guzman and M Campos and A Alvarez and F Morales-Zavala }, url = {https://www.mdpi.com/2079-4991/10/4/690}, isbn = {2079-4991}, year = {2020}, date = {2020-04-30}, journal = {Nanomaterials}, volume = {10}, number = {4}, pages = {690}, abstract = {The early detection of the amyloid beta peptide aggregates involved in Alzheimer’s disease is crucial to test new potential treatments. In this research, we improved the detection of amyloid beta peptide aggregates in vitro and ex vivo by fluorescence combining the use of CRANAD-2 and gold nanorods (GNRs) by the surface enhancement fluorescence effect. We synthetized GNRs and modified their surface with HS-PEG-OMe and HS-PEG-COOH and functionalized them with the D1 peptide, which has the capability to selectively bind to amyloid beta peptide. For an in vitro detection of amyloid beta peptide, we co-incubated amyloid beta peptide aggregates with the probe CRANAD-2 and GNR-PEG-D1 observing an increase in the intensity of the fluorescence signal attributed to surface enhancement fluorescence. Furthermore, the surface enhancement fluorescence effect was observed in brain slices of transgenic mice with Alzheimer´s disease co-incubated with CRANAD-2 and GNR-PEG-D1. An increase in the fluorescence signal was observed allowing the detection of aggregates that cannot be detected with the single use of CRANAD-2. Gold nanoparticles allowed an improvement in the detection of the amyloid aggregated by fluorescence in vitro and ex vivo. }, keywords = {}, pubstate = {published}, tppubtype = {article} } The early detection of the amyloid beta peptide aggregates involved in Alzheimer’s disease is crucial to test new potential treatments. In this research, we improved the detection of amyloid beta peptide aggregates in vitro and ex vivo by fluorescence combining the use of CRANAD-2 and gold nanorods (GNRs) by the surface enhancement fluorescence effect. We synthetized GNRs and modified their surface with HS-PEG-OMe and HS-PEG-COOH and functionalized them with the D1 peptide, which has the capability to selectively bind to amyloid beta peptide. For an in vitro detection of amyloid beta peptide, we co-incubated amyloid beta peptide aggregates with the probe CRANAD-2 and GNR-PEG-D1 observing an increase in the intensity of the fluorescence signal attributed to surface enhancement fluorescence. Furthermore, the surface enhancement fluorescence effect was observed in brain slices of transgenic mice with Alzheimer´s disease co-incubated with CRANAD-2 and GNR-PEG-D1. An increase in the fluorescence signal was observed allowing the detection of aggregates that cannot be detected with the single use of CRANAD-2. Gold nanoparticles allowed an improvement in the detection of the amyloid aggregated by fluorescence in vitro and ex vivo. |
Miranda-Rojas, S; Mendizabal, F Exploration of the Interaction Strength at the Interface of Anionic Chalcogen Anchors and Gold (111)-Based Nanomaterials Artículo de revista Nanomaterials, 10 (6), pp. 1237, 2020, ISBN: 2079-4991. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN27l, title = {Exploration of the Interaction Strength at the Interface of Anionic Chalcogen Anchors and Gold (111)-Based Nanomaterials}, author = {S Miranda-Rojas and F. Mendizabal}, url = {https://www.mdpi.com/2079-4991/10/6/1237}, isbn = {2079-4991}, year = {2020}, date = {2020-04-30}, journal = {Nanomaterials}, volume = {10}, number = {6}, pages = {1237}, abstract = {Nowadays, the use of sulfur-based ligands to modify gold-based materials has become a common trend. Here, we present a theoretical exploration of the modulation of the chalcogenides-gold interaction strength, using sulfur, selenium, and tellurium as anchor atoms. To characterize the chalcogenide-gold interaction, we designed a nanocluster of 42 gold atoms (Au42) to model a gold surface (111) and a series of 60 functionalized phenyl-chalcogenolate ligands to determine the ability of electron-donor and -withdrawing groups to modulate the interaction. The analysis of the interaction was performed by using energy decomposition analysis (EDA), non-covalent interactions index (NCI), and natural population analysis (NPA) to describe the charge transfer processes and to determine data correlation analyses. The results revealed that the magnitudes of the interaction energies increase following the order S < Se < Te, where this interaction strength can be augmented by electron-donor groups, under the donor-acceptor character the chalcogen\textendashgold interaction. We also found that the functionalization in meta position leads to better control of the interaction strength than the ortho substitution due to the steric and inductive effects involved when functionalized in this position.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Nowadays, the use of sulfur-based ligands to modify gold-based materials has become a common trend. Here, we present a theoretical exploration of the modulation of the chalcogenides-gold interaction strength, using sulfur, selenium, and tellurium as anchor atoms. To characterize the chalcogenide-gold interaction, we designed a nanocluster of 42 gold atoms (Au42) to model a gold surface (111) and a series of 60 functionalized phenyl-chalcogenolate ligands to determine the ability of electron-donor and -withdrawing groups to modulate the interaction. The analysis of the interaction was performed by using energy decomposition analysis (EDA), non-covalent interactions index (NCI), and natural population analysis (NPA) to describe the charge transfer processes and to determine data correlation analyses. The results revealed that the magnitudes of the interaction energies increase following the order S < Se < Te, where this interaction strength can be augmented by electron-donor groups, under the donor-acceptor character the chalcogen–gold interaction. We also found that the functionalization in meta position leads to better control of the interaction strength than the ortho substitution due to the steric and inductive effects involved when functionalized in this position. |
Areche, C; Hernandez, M; Cano, T; Ticona, J; Cortes, C; Simirgiotis, M; Caceres, F; Borquez, J; Echeverría, J; Sepulveda, B Frontiers in Pharmacology, 11 (417), 2020, ISSN: 1663-9812. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN6m, title = {Corryocactus Brevistylus (K. Schum. Ex Vaupel) Britton & Rose (Cactaceae): Antioxidant, Gastroprotective Effects, and Metabolomic Profiling by Ultrahigh-Pressure Liquid Chromatography and Electrospray High Resolution Orbitrap Tandem Mass Spectrometry}, author = {C Areche and M Hernandez and T Cano and J Ticona and C Cortes and M Simirgiotis and F Caceres and J Borquez and J Echeverr\'{i}a and B Sepulveda}, doi = {10.3389/fphar.2020.00417}, issn = {1663-9812}, year = {2020}, date = {2020-04-30}, journal = {Frontiers in Pharmacology}, volume = {11}, number = {417}, abstract = {Corryocactus brevistylus (K. Schum. ex Vaupel) Britton & Rose (Cactaceae) is a shrubby or often arborescent cactus popularly known as “sancayo” and produce an edible fruit known as “Sanky” which is consumed in Arequipa-Per\'{u}. The purpose of this study was to report the gastroprotective activity and relate this activity to the antioxidant capacity and presence of phenolic compounds for the first time. A metabolomic profiling based on Ultrahigh-pressure liquid chromatography and electrospray high resolution mass spectrometry, and the antioxidant activities (DPPH, ABTS, and FRAP), ascorbic acid content, total phenolics and flavonoids contents, and the mode of gastroprotective action of the Sanky fruit including the involvement of prostaglandins, nitric oxide, and sulfhydryl compounds is reported. Thirty-eight compounds were detected in the ethanolic extract including 12 organic acids, nine hydroxycinnamic acids, three isoamericanol derivatives, six flavonoids, five fatty acids, and two sterols. The results of the biological tests showed that the ethanolic extract had antioxidant capacity and gastroprotective activity on the model of HCl/EtOH-induced gastric lesions in mice (at 10, 25, 50, and 100 mg/kg). The effect elicited by the extract at 50 mg/kg was reversed by indometacin and N-ethylmaleimide but not by N^{G}-nitro-L-arginine methyl ester suggesting that sulfhydryl groups and prostaglandins are involved in the mode of gastroprotective action. In conclusion, our study proves that C. brevistylus pears have some gastroprotective and antioxidant capacities and consumption is recommended for the presence of several bioactive compounds.}, key = {Cactaceae,Corryocactus,Sancayo,Flavonoids,Gastroprotective,HPLC MS,Neglected species}, keywords = {}, pubstate = {published}, tppubtype = {article} } Corryocactus brevistylus (K. Schum. ex Vaupel) Britton & Rose (Cactaceae) is a shrubby or often arborescent cactus popularly known as “sancayo” and produce an edible fruit known as “Sanky” which is consumed in Arequipa-Perú. The purpose of this study was to report the gastroprotective activity and relate this activity to the antioxidant capacity and presence of phenolic compounds for the first time. A metabolomic profiling based on Ultrahigh-pressure liquid chromatography and electrospray high resolution mass spectrometry, and the antioxidant activities (DPPH, ABTS, and FRAP), ascorbic acid content, total phenolics and flavonoids contents, and the mode of gastroprotective action of the Sanky fruit including the involvement of prostaglandins, nitric oxide, and sulfhydryl compounds is reported. Thirty-eight compounds were detected in the ethanolic extract including 12 organic acids, nine hydroxycinnamic acids, three isoamericanol derivatives, six flavonoids, five fatty acids, and two sterols. The results of the biological tests showed that the ethanolic extract had antioxidant capacity and gastroprotective activity on the model of HCl/EtOH-induced gastric lesions in mice (at 10, 25, 50, and 100 mg/kg). The effect elicited by the extract at 50 mg/kg was reversed by indometacin and N-ethylmaleimide but not by NG-nitro-L-arginine methyl ester suggesting that sulfhydryl groups and prostaglandins are involved in the mode of gastroprotective action. In conclusion, our study proves that C. brevistylus pears have some gastroprotective and antioxidant capacities and consumption is recommended for the presence of several bioactive compounds. |
Calla-Quispe, E; Robles, J; Areche, C; Sepulveda, B Frontiers in Chemistry, 8 (450), 2020, ISSN: 2296-2646. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN4_36, title = {Are Ionic Liquids Better Extracting Agents Than Toxic Volatile Organic Solvents? A Combination of Ionic Liquids, Microwave and Lc/Ms/Ms, Applied to the Lichen Stereocaulon Glareosum}, author = {E Calla-Quispe and J Robles and C Areche and B Sepulveda}, doi = {10.3389/fchem.2020.00450}, issn = {2296-2646}, year = {2020}, date = {2020-04-30}, journal = {Frontiers in Chemistry}, volume = {8}, number = {450}, abstract = {We report a green strategy for the extraction of lichen substances from Stereocaulon glareosum. This sustainable alternative does not use volatile toxic organic solvents, but it is assisted by microwave and is checked by UHPLC/ESI/MS/MS. Ionic liquids may provide a better alternative in the extraction of natural products from lichens.}, key = {Lichens,Ionic Liquids,LC/MS,Natural Products,Stereocaulon}, keywords = {}, pubstate = {published}, tppubtype = {article} } We report a green strategy for the extraction of lichen substances from Stereocaulon glareosum. This sustainable alternative does not use volatile toxic organic solvents, but it is assisted by microwave and is checked by UHPLC/ESI/MS/MS. Ionic liquids may provide a better alternative in the extraction of natural products from lichens. |
Molina, C; Toro, R; Manzano, C A; Canepari, S; Massimi, L; Leiva, M A Airborne Aerosols and Human Health: Leapfrogging from Mass Concentration to Oxidative Potential Artículo de revista Atmosphere, 11 (9), pp. 917, 2020, ISBN: 2073-4433. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN35i, title = {Airborne Aerosols and Human Health: Leapfrogging from Mass Concentration to Oxidative Potential}, author = {C Molina and R. Toro and C A Manzano and S Canepari and L Massimi and M.A. Leiva}, url = {https://www.mdpi.com/2073-4433/11/9/917%20}, doi = {https://doi.org/10.3390/atmos11090917}, isbn = {2073-4433}, year = {2020}, date = {2020-04-30}, journal = {Atmosphere}, volume = {11}, number = {9}, pages = {917}, abstract = {The mass concentration of atmospheric particulate matter (PM) has been systematically used in epidemiological studies as an indicator of exposure to air pollutants, connecting PM concentrations with a wide variety of human health effects. However, these effects can be hardly explained by using one single parameter, especially because PM is formed by a complex mixture of chemicals. Current research has shown that many of these adverse health effects can be derived from the oxidative stress caused by the deposition of PM in the lungs. The oxidative potential (OP) of the PM, related to the presence of transition metals and organic compounds that can induce the production of reactive oxygen and nitrogen species (ROS/RNS), could be a parameter to evaluate these effects. Therefore, estimating the OP of atmospheric PM would allow us to evaluate and integrate the toxic potential of PM into a unique parameter, which is related to emission sources, size distribution and/or chemical composition. However, the association between PM and particle-induced toxicity is still largely unknown. In this commentary article, we analyze how this new paradigm could help to deal with some unanswered questions related to the impact of atmospheric PM over human health}, keywords = {}, pubstate = {published}, tppubtype = {article} } The mass concentration of atmospheric particulate matter (PM) has been systematically used in epidemiological studies as an indicator of exposure to air pollutants, connecting PM concentrations with a wide variety of human health effects. However, these effects can be hardly explained by using one single parameter, especially because PM is formed by a complex mixture of chemicals. Current research has shown that many of these adverse health effects can be derived from the oxidative stress caused by the deposition of PM in the lungs. The oxidative potential (OP) of the PM, related to the presence of transition metals and organic compounds that can induce the production of reactive oxygen and nitrogen species (ROS/RNS), could be a parameter to evaluate these effects. Therefore, estimating the OP of atmospheric PM would allow us to evaluate and integrate the toxic potential of PM into a unique parameter, which is related to emission sources, size distribution and/or chemical composition. However, the association between PM and particle-induced toxicity is still largely unknown. In this commentary article, we analyze how this new paradigm could help to deal with some unanswered questions related to the impact of atmospheric PM over human health |
Orenha, R P; Silva, Da V B; Caramori, G F; Schneider, De Souza F S; Piotrowski, M J; Contreras-Garcia, J; Cardenas, C; Gonçalves, Briese M; Mendizabal, F; Parreira, R L T On the Recognition of Chloride, Bromide and Nitrate Anions by Anthracene–Squaramide Conjugated Compounds: A Computational Perspective Artículo de revista New Journal of Chemistry, 44 (41), pp. 17831-17839, 2020, ISSN: 1144-0546. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN29j, title = {On the Recognition of Chloride, Bromide and Nitrate Anions by Anthracene\textendashSquaramide Conjugated Compounds: A Computational Perspective}, author = {R P Orenha and V B Da Silva and G F Caramori and F S De Souza Schneider and M J Piotrowski and J Contreras-Garcia and C Cardenas and M Briese Gon\c{c}alves and F. Mendizabal and R L T Parreira}, doi = {10.1039/D0NJ03685D}, issn = {1144-0546}, year = {2020}, date = {2020-03-31}, journal = {New Journal of Chemistry}, volume = {44}, number = {41}, pages = {17831-17839}, abstract = {Anion recognition is widely used in several biological fields. Squaramide derived compounds appear as potential structures to recognize anions. Here, the bond mechanisms between the chloride (Cl−), bromide (Br−) and nitrate (NO3−) anions and anthracene\textendashsquaramide conjugated compounds are elucidated considering the influence of the: (i) number, (ii) nature, and (iii) position of the substituents: trifluoromethyl (\textendashCF3) and nitro (\textendashNO2). Energy decomposition analysis (EDA) shows that the interactions between Cl−, Br− and NO3− and anthracene\textendashsquaramide have an attractive interaction energy supported predominantly by electrostatic energy followed by orbital contribution. Molecular electrostatic potential (MEP) surfaces imply electrostatic interactions between Cl−, Br− and the oxygen atom from NO3− and the hydrogen atoms from N\textendashH and C\textendashH bonds present in the squaramide structure, and an aryl group, respectively. Cl− interacts with the receptors more strongly than Br−. The NO3− recognition is less attractive than those presented by Cl− and Br−, in agreement with the hardness\textendashsoftness features of these anions. Importantly, one and, mostly, two group substitutions, \textendashH → \textendashCF3 or \textendashNO2, favor the recognition of Cl−, Br− and NO3− due to the increase of the polarization in the receptor\textendashNH⋯anion interaction. The \textendashNO2 group promotes a larger effect relative to the \textendashCF3 ligand. The \textendashNO2 ligand positioned at the largest distance conceivable to the benzene\textendashNH group promotes the lowest interference in the N\textendashH⋯Cl− interaction. These results provide information to design receptors with a larger capability to recognize anions.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Anion recognition is widely used in several biological fields. Squaramide derived compounds appear as potential structures to recognize anions. Here, the bond mechanisms between the chloride (Cl−), bromide (Br−) and nitrate (NO3−) anions and anthracene–squaramide conjugated compounds are elucidated considering the influence of the: (i) number, (ii) nature, and (iii) position of the substituents: trifluoromethyl (–CF3) and nitro (–NO2). Energy decomposition analysis (EDA) shows that the interactions between Cl−, Br− and NO3− and anthracene–squaramide have an attractive interaction energy supported predominantly by electrostatic energy followed by orbital contribution. Molecular electrostatic potential (MEP) surfaces imply electrostatic interactions between Cl−, Br− and the oxygen atom from NO3− and the hydrogen atoms from N–H and C–H bonds present in the squaramide structure, and an aryl group, respectively. Cl− interacts with the receptors more strongly than Br−. The NO3− recognition is less attractive than those presented by Cl− and Br−, in agreement with the hardness–softness features of these anions. Importantly, one and, mostly, two group substitutions, –H → –CF3 or –NO2, favor the recognition of Cl−, Br− and NO3− due to the increase of the polarization in the receptor–NH⋯anion interaction. The –NO2 group promotes a larger effect relative to the –CF3 ligand. The –NO2 ligand positioned at the largest distance conceivable to the benzene–NH group promotes the lowest interference in the N–H⋯Cl− interaction. These results provide information to design receptors with a larger capability to recognize anions. |
Tamayo, L; Melo, F; Caballero, L; Hamm, E; Díaz, M; Leal, M S; Guiliani, N; Urzua, M Does Bacterial Elasticity Affect Adhesion to Polymer Fibers? Artículo de revista ACS Applied Materials & Interfaces, 12 (12), pp. 14507-14517, 2020, ISSN: 1944-8244 . Resumen | Enlaces | BibTeX | Etiquetas: @article{RN14m, title = {Does Bacterial Elasticity Affect Adhesion to Polymer Fibers?}, author = {L. Tamayo and F Melo and L Caballero and E Hamm and M D\'{i}az and M S Leal and N Guiliani and M. Urzua}, doi = {10.1021/acsami.9b21060}, issn = {1944-8244 }, year = {2020}, date = {2020-03-25}, journal = {ACS Applied Materials & Interfaces}, volume = {12}, number = {12}, pages = {14507-14517}, abstract = {The factors governing bacterial adhesion to substrates with different topographies are still not fully identified. The present work seeks to elucidate for the first time and with quantitative data the roles of bacterial elasticity and shape and substrate topography in bacterial adhesion. With this aim, populations of three bacterial species, P. aeruginosa DSM 22644, B. subtilis DSM 10, and S. aureus DSM 20231 adhered on flat substrates covered with electrospun polycaprolactone fibers of different diameters ranging from 0.4 to 5.5 μm are counted. Populations of bacterial cells are classified according to the preferred binding sites of the bacteria to the substrate. The colloidal probe technique was used to assess the stiffness of the bacteria and bacteria\textendashpolymer surface adhesion energy. A theoretical model is developed to interpret the observed populations in terms of a balance between stiffness and adhesion energy of the bacteria. The model, which also incorporates the radius of the fiber and the size and shape of the bacteria, predicts increased adhesion for a low level of stiffness and for a larger number of available bacteria\textendashfiber contact points. Te adhesive propensity of bacteria depends in a nontrivial way on the radius of the fibers due to the random arrangement of fibers.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The factors governing bacterial adhesion to substrates with different topographies are still not fully identified. The present work seeks to elucidate for the first time and with quantitative data the roles of bacterial elasticity and shape and substrate topography in bacterial adhesion. With this aim, populations of three bacterial species, P. aeruginosa DSM 22644, B. subtilis DSM 10, and S. aureus DSM 20231 adhered on flat substrates covered with electrospun polycaprolactone fibers of different diameters ranging from 0.4 to 5.5 μm are counted. Populations of bacterial cells are classified according to the preferred binding sites of the bacteria to the substrate. The colloidal probe technique was used to assess the stiffness of the bacteria and bacteria–polymer surface adhesion energy. A theoretical model is developed to interpret the observed populations in terms of a balance between stiffness and adhesion energy of the bacteria. The model, which also incorporates the radius of the fiber and the size and shape of the bacteria, predicts increased adhesion for a low level of stiffness and for a larger number of available bacteria–fiber contact points. Te adhesive propensity of bacteria depends in a nontrivial way on the radius of the fibers due to the random arrangement of fibers. |
Salgado, F; Caballero, J; Vargas, R; Cornejo, A; Areche, C Natural Product Research, 34 (5), pp. 646-650, 2020, ISSN: 1478-6419. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN7l, 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}, doi = {10.1080/14786419.2018.1492576}, issn = {1478-6419}, year = {2020}, date = {2020-03-03}, journal = {Natural Product Research}, volume = {34}, number = {5}, pages = {646-650}, 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. |
Paredes-Gil, K; Páez-Hernández, D; Arratia-Pérez, R; Mendizabal, F Insights into the Role of D-a-Π-a Type Pro-Aromatic Organic Dyes with Thieno[3,4-B]Pyrazine as a Acceptor Group into Dye-Sensitized Solar-Cells. A Td-Dft/Periodic Dft Study Artículo de revista International Journal of Quantum Chemistry, 120 (5), pp. e26108, 2020, ISSN: 0020-7608. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN25m, title = {Insights into the Role of D-a-Π-a Type Pro-Aromatic Organic Dyes with Thieno[3,4-B]Pyrazine as a Acceptor Group into Dye-Sensitized Solar-Cells. A Td-Dft/Periodic Dft Study}, author = {K Paredes-Gil and D P\'{a}ez-Hern\'{a}ndez and R Arratia-P\'{e}rez and F. Mendizabal}, doi = {https://doi.org/10.1002/qua.26108}, issn = {0020-7608}, year = {2020}, date = {2020-03-01}, journal = {International Journal of Quantum Chemistry}, volume = {120}, number = {5}, pages = {e26108}, abstract = {Abstract Time-dependent density functional theory (TD-DFT)/periodic DFT calculations were performed to determine the role of pro-aromatic organic D-A-π-A type dyes (the NL1-NL17 family) with Thieno[3,4-b]pyrazine (Tpy) as A acceptor group into dye-sensitized solar-cells (DSSC). This work presents a discussion of the ground and excited states of these dyes along with the aromaticity analysis and the electron injection step using a dye@(TiO2)72 model. The results suggest that the pro-aromatic behavior increases from the thiophene ring to the pyrazine when an acceptor π-bridge such as phenyl is used. This strong pro-aromaticity is also reflected in the electron injection step, studied using a 3x2 3 layer (TiO2)72 slab model. The resulting adsorption energies (?Eads and ?Gads) and the electron injection (?Ginject) in the stablest coordination mode, Bid_CN_COOH, indicate that the redox reaction (Dye* ? Dye+ + e?) is stronger and more spon than the adsorption reaction (Dye+ +?TiO2 [+e?] ? Dye@TiO2) in the electron injection. In this way, the highest efficiency of NL6 and NL12 is a consequence of the more significant pro-aromatic characteristics and the more spontaneous redox process. Finally, these NL dyes are promising in the molecular engineering of D-A-π-A metal-free types dyes.}, key = {D-A-π-A dyes metal-free organic dyes pro-aromatic molecules solar cell TiO2 surface}, keywords = {}, pubstate = {published}, tppubtype = {article} } Abstract Time-dependent density functional theory (TD-DFT)/periodic DFT calculations were performed to determine the role of pro-aromatic organic D-A-π-A type dyes (the NL1-NL17 family) with Thieno[3,4-b]pyrazine (Tpy) as A acceptor group into dye-sensitized solar-cells (DSSC). This work presents a discussion of the ground and excited states of these dyes along with the aromaticity analysis and the electron injection step using a dye@(TiO2)72 model. The results suggest that the pro-aromatic behavior increases from the thiophene ring to the pyrazine when an acceptor π-bridge such as phenyl is used. This strong pro-aromaticity is also reflected in the electron injection step, studied using a 3x2 3 layer (TiO2)72 slab model. The resulting adsorption energies (?Eads and ?Gads) and the electron injection (?Ginject) in the stablest coordination mode, Bid_CN_COOH, indicate that the redox reaction (Dye* ? Dye+ + e?) is stronger and more spon than the adsorption reaction (Dye+ +?TiO2 [+e?] ? Dye@TiO2) in the electron injection. In this way, the highest efficiency of NL6 and NL12 is a consequence of the more significant pro-aromatic characteristics and the more spontaneous redox process. Finally, these NL dyes are promising in the molecular engineering of D-A-π-A metal-free types dyes. |
Cárcamo-Vega, J J; Brañes, M R; Loske, A M; Campos-Vallette, M The Influence of the Number of Shock Waves and the Energy Flux Density on the Raman Spectrum of Collagen Type I from Rat Artículo de revista Shock Waves, 30 (2), pp. 201-214, 2020, ISSN: 1432-2153. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN58b, title = {The Influence of the Number of Shock Waves and the Energy Flux Density on the Raman Spectrum of Collagen Type I from Rat}, author = {J J C\'{a}rcamo-Vega and M R Bra\~{n}es and A M Loske and M Campos-Vallette}, doi = {10.1007/s00193-019-00920-4}, issn = {1432-2153}, year = {2020}, date = {2020-03-01}, journal = {Shock Waves}, volume = {30}, number = {2}, pages = {201-214}, abstract = {Shock waves are used to treat musculoskeletal injuries and trigger the body’s mechanisms to initiate healing; however, the cellular and molecular working mechanisms are not fully known. Raman spectroscopy may be a useful tool to provide information on structural changes. Solid collagen type I from rat tail (> 90% pure) was suspended in water and was exposed in vitro to different numbers of shock waves and energy flux densities. Raman spectra were recorded at 2 h, 1 week, and 3 weeks after shock-wave treatment. The spectral analysis indicated that varying the number of shock waves and the energy flux density induced molecular changes in the collagen structure. Varying the energy flux density induced more significant changes than modifying the number of shock waves; however, in most cases, the collagen recovered its original conformation 3 weeks after treatment. A significant decrease in the relative intensities of the conformational bands, which include amide I, amide III, and stretching C\textendashC, was observed at different energy flux densities. In many clinical cases, the natural repair of tissue is improved after shock-wave treatment. Raman spectroscopy revealed that varying the energy flux density of the shock waves applied to rat collagen type I induced strong conformational molecular changes. Approximately 2\textendash3 weeks after shock-wave treatment, a phase of “molecular ordering” tending to a “recovering molecular sequence repair” was observed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Shock waves are used to treat musculoskeletal injuries and trigger the body’s mechanisms to initiate healing; however, the cellular and molecular working mechanisms are not fully known. Raman spectroscopy may be a useful tool to provide information on structural changes. Solid collagen type I from rat tail (> 90% pure) was suspended in water and was exposed in vitro to different numbers of shock waves and energy flux densities. Raman spectra were recorded at 2 h, 1 week, and 3 weeks after shock-wave treatment. The spectral analysis indicated that varying the number of shock waves and the energy flux density induced molecular changes in the collagen structure. Varying the energy flux density induced more significant changes than modifying the number of shock waves; however, in most cases, the collagen recovered its original conformation 3 weeks after treatment. A significant decrease in the relative intensities of the conformational bands, which include amide I, amide III, and stretching C–C, was observed at different energy flux densities. In many clinical cases, the natural repair of tissue is improved after shock-wave treatment. Raman spectroscopy revealed that varying the energy flux density of the shock waves applied to rat collagen type I induced strong conformational molecular changes. Approximately 2–3 weeks after shock-wave treatment, a phase of “molecular ordering” tending to a “recovering molecular sequence repair” was observed. |
Dantas, D; Bressan-Smith, R; Noriega, X; Pérez, F J Buds of “Italia Melhorada” Grapevines Grown under Tropical Conditions Develop a Quiescent State Artículo de revista Environmental and Experimental Botany, 171 , pp. 103951, 2020, ISSN: 0098-8472 . Resumen | Enlaces | BibTeX | Etiquetas: @article{RN51b, title = {Buds of “Italia Melhorada” Grapevines Grown under Tropical Conditions Develop a Quiescent State}, author = {D Dantas and R Bressan-Smith and X Noriega and F J P\'{e}rez}, doi = {https://doi.org/10.1016/j.envexpbot.2019.103951}, issn = {0098-8472 }, year = {2020}, date = {2020-03-01}, journal = {Environmental and Experimental Botany}, volume = {171}, pages = {103951}, abstract = {A double cropping system for the grapevine (Vitis vinifera L) has been commercially adopted for use in regions where the tropical climate is characterized by high temperatures and small variations in daylength throughout the year. Under these climatic conditions, the use of hydrogen cyanamide (HC), a compound that breaks bud dormancy, is mandatory to produce homogeneous budbreak. However, it is unknown whether grapevine buds are capable of developing endodormancy (ED) under these climatic conditions. In this study, typical signals of ED, such as the number of nodes per cane, the development of periderm and the thickening of the cell wall of the bud meristematic cells, were analysed in vines of “Italia melhorada” grown in Mossor\'{o}, Brazil (5°12′16″S), under a natural (ND) photoperiod (12/12 h), a short-day (SD) photoperiod (10/14 h) and a long-day (LD) photoperiod (14/10 h). The abundance of phytochrome A (VvPHYA) and B (VvPHYB) and FLOWERING LOCUS T (VvFT) transcripts in the leaves and buds was also determined. The results showed a reduced number of nodes per cane and development of the periderm in the shoots of grapevines grown under ND and SD photoperiods. In addition, compared with that under the LD photoperiod, the expression of VvPHYA and VvFT under the ND and SD-photoperiod decreased, and the expression of VvPHYB increased. However, the thickness of the cell wall of the bud meristematic cells increased only in the grapevines exposed to the SD photoperiod. Therefore, we hypothesize that cell wall thickening is a characteristic of ED, while decreased expression of VvPHYA and VvFT and increased expression of VvPHYB are characteristic of quiescence. Consequently, under a tropical conditions, the grapevine buds would be in a quiescent state and not in a dormant state.}, key = {Grapevine buds Dormancy Quiescence Photoperiod Phytochromes}, keywords = {}, pubstate = {published}, tppubtype = {article} } A double cropping system for the grapevine (Vitis vinifera L) has been commercially adopted for use in regions where the tropical climate is characterized by high temperatures and small variations in daylength throughout the year. Under these climatic conditions, the use of hydrogen cyanamide (HC), a compound that breaks bud dormancy, is mandatory to produce homogeneous budbreak. However, it is unknown whether grapevine buds are capable of developing endodormancy (ED) under these climatic conditions. In this study, typical signals of ED, such as the number of nodes per cane, the development of periderm and the thickening of the cell wall of the bud meristematic cells, were analysed in vines of “Italia melhorada” grown in Mossoró, Brazil (5°12′16″S), under a natural (ND) photoperiod (12/12 h), a short-day (SD) photoperiod (10/14 h) and a long-day (LD) photoperiod (14/10 h). The abundance of phytochrome A (VvPHYA) and B (VvPHYB) and FLOWERING LOCUS T (VvFT) transcripts in the leaves and buds was also determined. The results showed a reduced number of nodes per cane and development of the periderm in the shoots of grapevines grown under ND and SD photoperiods. In addition, compared with that under the LD photoperiod, the expression of VvPHYA and VvFT under the ND and SD-photoperiod decreased, and the expression of VvPHYB increased. However, the thickness of the cell wall of the bud meristematic cells increased only in the grapevines exposed to the SD photoperiod. Therefore, we hypothesize that cell wall thickening is a characteristic of ED, while decreased expression of VvPHYA and VvFT and increased expression of VvPHYB are characteristic of quiescence. Consequently, under a tropical conditions, the grapevine buds would be in a quiescent state and not in a dormant state. |
Ruiz-Fernández, Á R; Villanelo, F; Gutierrez-Maldonado, S E; Pareja-Barrueto, C; Weiss-Lopez, B; Perez-Acle, T L-Dopa Modulates the Kinetics but Not the Thermodynamic Equilibrium of Tta+ Amphiphiles Forming Lyotropic Nematic Liquid Crystals Artículo de revista RSC Advances, 10 (26), pp. 15366-15374, 2020. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN17k, title = {L-Dopa Modulates the Kinetics but Not the Thermodynamic Equilibrium of Tta+ Amphiphiles Forming Lyotropic Nematic Liquid Crystals}, author = {\'{A} R Ruiz-Fern\'{a}ndez and F Villanelo and S E Gutierrez-Maldonado and C Pareja-Barrueto and B. Weiss-Lopez and T Perez-Acle}, doi = {10.1039/D0RA00764A}, year = {2020}, date = {2020-01-01}, journal = {RSC Advances}, volume = {10}, number = {26}, pages = {15366-15374}, abstract = {Lyotropic liquid crystals (LLCs) are mixtures of amphiphile molecules usually studied as mimetic of biological membrane. The equilibrium dynamics of tetradecyltrimethyl ammonium cation (TTA+) molecules forming nematic LLCs (LNLCs) is guided by a dive-in mechanism where TTA+ molecules spontaneously leave and re-enter the bicelle. Of note, this dynamic behavior could be exploited to produce drug nano-delivery systems based on LNLCs. Therefore, the understanding of the effect of pharmaceutically interesting molecules in the dynamics of the dive-in mechanism should be crucial for drug delivery applications. In this work, we studied the effects of l-DOPA in the equilibrium dynamics of TTA+ bicelles forming LNLCs, employing a transdisciplinary approach based on 2H-NMR together with molecular modeling and molecular dynamics simulations. Our data suggest that l-DOPA perturbs the kinetic of the dive-in mechanism but not the thermodynamics of this process. As whole, our results provide fundamental insights on the mechanisms by which l-DOPA govern the equilibrium of LNLCs bicelles.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Lyotropic liquid crystals (LLCs) are mixtures of amphiphile molecules usually studied as mimetic of biological membrane. The equilibrium dynamics of tetradecyltrimethyl ammonium cation (TTA+) molecules forming nematic LLCs (LNLCs) is guided by a dive-in mechanism where TTA+ molecules spontaneously leave and re-enter the bicelle. Of note, this dynamic behavior could be exploited to produce drug nano-delivery systems based on LNLCs. Therefore, the understanding of the effect of pharmaceutically interesting molecules in the dynamics of the dive-in mechanism should be crucial for drug delivery applications. In this work, we studied the effects of l-DOPA in the equilibrium dynamics of TTA+ bicelles forming LNLCs, employing a transdisciplinary approach based on 2H-NMR together with molecular modeling and molecular dynamics simulations. Our data suggest that l-DOPA perturbs the kinetic of the dive-in mechanism but not the thermodynamics of this process. As whole, our results provide fundamental insights on the mechanisms by which l-DOPA govern the equilibrium of LNLCs bicelles. |
Núñez, A; Manzano, C A; Chi, C Health Outcomes, Utilization, and Equity in Chile: An Evolution from 1990 to 2015 and the Effects of the Last Health Reform Artículo de revista Public Health, 178 , pp. 38-48, 2020, ISSN: 0033-3506. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN40l, title = {Health Outcomes, Utilization, and Equity in Chile: An Evolution from 1990 to 2015 and the Effects of the Last Health Reform}, author = {A N\'{u}\~{n}ez and C A Manzano and C Chi}, url = {https://www.sciencedirect.com/science/article/pii/S003335061930277X}, doi = {https://doi.org/10.1016/j.puhe.2019.08.017}, issn = {0033-3506}, year = {2020}, date = {2020-01-01}, journal = {Public Health}, volume = {178}, pages = {38-48}, abstract = {Objective Chile is an attractive case study because of the deep political changes that it underwent over a short period of time: from a universal health service (60s), through a neoliberal reform (70s) and onto a series of legislative reforms (80s\textendash90s). This article aims to explore and assess the evolution of health outcomes, equity, and utilization in Chile through the last period of these reforms (1990\textendash2015). Study design Standardized health equity analysis. Methods We conducted a standardized economic analysis on health equity and healthcare utilization using the ADePT software (by the World Bank) and using data from the Chilean National Socio-economic Survey. We evaluated trends of health equity and examined concentration curves of health utilization of healthcare services and health outcomes such as children/elder/pregnant nutritional status, self-reported health, and physical limitations. Results Health outcomes such as nutritional problems in children and pregnant women were concentrated among the poor, while others such as high-relevance health conditions were similar for poorest and richest households. The concentration indexes for health outcomes suggested that income makes the distribution pro-poor. However, the opposite was true for age, in which the probability of health problems among rich individuals increased with age. The concentration curves for utilization of healthcare services showed that dental visits, laboratory exams, specialty visits, and hospitalizations were concentrated on the richest households, while the use of emergency services and preventive medicine were highly concentrated among poor individuals. Conclusions Although a positive trend in the increase of healthcare service use among income groups was observed, a significant impact of the latest health reform was not observed.}, key = {Equity in health access Chile Concentration curves Health reform Nutrition}, keywords = {}, pubstate = {published}, tppubtype = {article} } Objective Chile is an attractive case study because of the deep political changes that it underwent over a short period of time: from a universal health service (60s), through a neoliberal reform (70s) and onto a series of legislative reforms (80s–90s). This article aims to explore and assess the evolution of health outcomes, equity, and utilization in Chile through the last period of these reforms (1990–2015). Study design Standardized health equity analysis. Methods We conducted a standardized economic analysis on health equity and healthcare utilization using the ADePT software (by the World Bank) and using data from the Chilean National Socio-economic Survey. We evaluated trends of health equity and examined concentration curves of health utilization of healthcare services and health outcomes such as children/elder/pregnant nutritional status, self-reported health, and physical limitations. Results Health outcomes such as nutritional problems in children and pregnant women were concentrated among the poor, while others such as high-relevance health conditions were similar for poorest and richest households. The concentration indexes for health outcomes suggested that income makes the distribution pro-poor. However, the opposite was true for age, in which the probability of health problems among rich individuals increased with age. The concentration curves for utilization of healthcare services showed that dental visits, laboratory exams, specialty visits, and hospitalizations were concentrated on the richest households, while the use of emergency services and preventive medicine were highly concentrated among poor individuals. Conclusions Although a positive trend in the increase of healthcare service use among income groups was observed, a significant impact of the latest health reform was not observed. |
Mendizabal, F; Miranda-Rojas, S Electronic and Optical Properties of [Au(Ch3css)]4 Cluster. A Quantum Chemistry Study Artículo de revista RSC Advances, 10 (55), pp. 33549-33557, 2020. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN28m, title = {Electronic and Optical Properties of [Au(Ch3css)]4 Cluster. A Quantum Chemistry Study}, author = {F. Mendizabal and S Miranda-Rojas}, doi = {10.1039/D0RA06982E}, year = {2020}, date = {2020-01-01}, journal = {RSC Advances}, volume = {10}, number = {55}, pages = {33549-33557}, abstract = {The uses of the sulfur\textendashgold bond in the design of new molecular clusters have gained increasing attention in recent years. Their size and shape are diverse providing a wide variety of optical and electronic properties. Here we present a computational study of the absorption and emission properties of a small [Au(dithioacetate)]4 cluster as a model for these systems. The electronic structure of the Au4S8 core of this cluster permits rationalization of the source of the optical properties and how these are connected with that specific structural scaffold. Due to the complex nature of the aurophilic intramolecular interactions taking place in this system, several methods were used, such as the MP2, SCS-MP2, PBE-D3, and TPSS-D3 levels; both in gas and solvent phases. The absorption spectra of the cluster were calculated by the single excitation time-dependent-DFT (TD-DFT) method, CC2, SCS-CC2, and ADC(2) levels. The ab initio correlated calculations and previously reported experimental data have been used to assess the performance of our calculations. Moreover, the emission T1\textendashSo transition was calculated, where the SCS-CC2 level showed an excellent agreement with the experimental results. The core Au4S8 was identified as mainly responsible for the absorption and emission transitions according to the theoretical model.}, keywords = {}, pubstate = {published}, tppubtype = {article} } The uses of the sulfur–gold bond in the design of new molecular clusters have gained increasing attention in recent years. Their size and shape are diverse providing a wide variety of optical and electronic properties. Here we present a computational study of the absorption and emission properties of a small [Au(dithioacetate)]4 cluster as a model for these systems. The electronic structure of the Au4S8 core of this cluster permits rationalization of the source of the optical properties and how these are connected with that specific structural scaffold. Due to the complex nature of the aurophilic intramolecular interactions taking place in this system, several methods were used, such as the MP2, SCS-MP2, PBE-D3, and TPSS-D3 levels; both in gas and solvent phases. The absorption spectra of the cluster were calculated by the single excitation time-dependent-DFT (TD-DFT) method, CC2, SCS-CC2, and ADC(2) levels. The ab initio correlated calculations and previously reported experimental data have been used to assess the performance of our calculations. Moreover, the emission T1–So transition was calculated, where the SCS-CC2 level showed an excellent agreement with the experimental results. The core Au4S8 was identified as mainly responsible for the absorption and emission transitions according to the theoretical model. |
García-Beltrán, O; Areche, C; Galdámez, A; Moris, S The Crystal Structure of 1-Carboxy-2-(1h-Indol-3-Yl)-N,N,N-Trimethylethan-1-Ammonium Chloride, C14h19n2o2cl Artículo de revista Zeitschrift für Kristallographie - New Crystal Structures, 235 (5), pp. 1183-1185, 2020. @article{RN8k, title = {The Crystal Structure of 1-Carboxy-2-(1h-Indol-3-Yl)-N,N,N-Trimethylethan-1-Ammonium Chloride, C14h19n2o2cl}, author = {O Garc\'{i}a-Beltr\'{a}n and C Areche and A Gald\'{a}mez and S Moris}, doi = {doi:10.1515/ncrs-2020-0240}, year = {2020}, date = {2020-01-01}, journal = {Zeitschrift f\"{u}r Kristallographie - New Crystal Structures}, volume = {235}, number = {5}, pages = {1183-1185}, keywords = {}, pubstate = {published}, tppubtype = {article} } |
Copaja, S; Tessada, R M Seasonal and Spatial Variation of Trace Elements in Sediments of Three Chilean Basins Artículo de revista Journal of the Chilean Chemical Society, 65 (1), pp. 4737-4745, 2020. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN23k, title = {Seasonal and Spatial Variation of Trace Elements in Sediments of Three Chilean Basins}, author = {S. Copaja and R M Tessada}, url = {http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-97072020000104737&lng=en&nrm=iso&tlng=en}, doi = {10.4067/S0717-97072020000104737}, year = {2020}, date = {2020-01-01}, journal = {Journal of the Chilean Chemical Society}, volume = {65}, number = {1}, pages = {4737-4745}, abstract = {Total concentrations of trace elements can provide fundamental information on the sediment contamination levels of the pollution indexes and the quality guidelines for sediment risk assessment. However, this information alone is insufficient to understand the mobility, bioavailability and toxicity of these elements in the sediment, since the environmental behavior of trace elements depends largely on their chemical form and binding states. Thus it is important to determine the soluble or labile fraction, since the elements of this fraction will be the most mobile and bioavailable. In this study we analyze the seasonal and spatial variation of labile fraction trace elements concentration in three Chilean river basins. We also study the impact of mining nearby in one of the sites studied in the three basins. Samples were taken in spring (November); summer (January), autumn (May) and winter (June). Sediment samples from three selected basins: Aconcagua, Cachapoal and Choapa basins were collected at different points in the river. Six sampling points were chosen in three areas: one station without human intervention (ritron: E1), two in the area of middle ritron (E2-E3) and a third in the sector potamon where increased sedimentation (E4-E5-E6). In the three basins site E2 could be influenced by mining activities, site E2 in the Cachapoal basin is influenced by the El Teniente mine; site E2 in the Aconcagua basin influenced by the Cerro Blanco mine and site E2 in the Choapa basin is influenced by the Los Pelambres mine. Physical chemical characteristic of sediment were done by described methods. The labile or soluble fraction of Al, As, Cd, Cu, Cr, Fe, Mn, Mo, Ni, Pb and Zn, was extracted from the sediment with acetic acid. Metals were analyzed by ICP-OES. The eleven trace elements analyzed in the labile fraction were detected in the three basins in most of the stations. The high concentration of Al, Cu, Fe, Mn, Zn in the labile fraction found in the E2 site in the three basins demonstrates the influence of mining activities near this site. The mobility of trace elements to the other sites is depending on the characteristics of the basins. Variation between seasons and sites was observed.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Total concentrations of trace elements can provide fundamental information on the sediment contamination levels of the pollution indexes and the quality guidelines for sediment risk assessment. However, this information alone is insufficient to understand the mobility, bioavailability and toxicity of these elements in the sediment, since the environmental behavior of trace elements depends largely on their chemical form and binding states. Thus it is important to determine the soluble or labile fraction, since the elements of this fraction will be the most mobile and bioavailable. In this study we analyze the seasonal and spatial variation of labile fraction trace elements concentration in three Chilean river basins. We also study the impact of mining nearby in one of the sites studied in the three basins. Samples were taken in spring (November); summer (January), autumn (May) and winter (June). Sediment samples from three selected basins: Aconcagua, Cachapoal and Choapa basins were collected at different points in the river. Six sampling points were chosen in three areas: one station without human intervention (ritron: E1), two in the area of middle ritron (E2-E3) and a third in the sector potamon where increased sedimentation (E4-E5-E6). In the three basins site E2 could be influenced by mining activities, site E2 in the Cachapoal basin is influenced by the El Teniente mine; site E2 in the Aconcagua basin influenced by the Cerro Blanco mine and site E2 in the Choapa basin is influenced by the Los Pelambres mine. Physical chemical characteristic of sediment were done by described methods. The labile or soluble fraction of Al, As, Cd, Cu, Cr, Fe, Mn, Mo, Ni, Pb and Zn, was extracted from the sediment with acetic acid. Metals were analyzed by ICP-OES. The eleven trace elements analyzed in the labile fraction were detected in the three basins in most of the stations. The high concentration of Al, Cu, Fe, Mn, Zn in the labile fraction found in the E2 site in the three basins demonstrates the influence of mining activities near this site. The mobility of trace elements to the other sites is depending on the characteristics of the basins. Variation between seasons and sites was observed. |
Herrera, B A; Bruna, T C; Sierpe, R A; Lang, E P; Urzúa, M; Flores, M I; Jara, P; Yutronic, N A Surface Functionalized with Per-(6-Amino-6-Deoxy)-Β-Cyclodextrin for Potential Organic Pollutant Removal from Water Artículo de revista Carbohydrate Polymers, 233 (7), pp. 115865, 2020, ISSN: 0144-8617. Resumen | Enlaces | BibTeX | Etiquetas: activity, calculations, cyclodextrin, Surface Functionalized @article{RN75, title = {A Surface Functionalized with Per-(6-Amino-6-Deoxy)-Β-Cyclodextrin for Potential Organic Pollutant Removal from Water}, author = {B A Herrera and T C Bruna and R A Sierpe and E P Lang and M. Urz\'{u}a and M I Flores and P. Jara and N. Yutronic}, url = {http://www.sciencedirect.com/science/article/pii/S0144861720300394}, doi = {https://doi.org/10.1016/j.carbpol.2020.115865}, issn = {0144-8617}, year = {2020}, date = {2020-01-01}, journal = {Carbohydrate Polymers}, volume = {233}, number = {7}, pages = {115865}, publisher = {2012 Elsevier Inc.}, abstract = {In this work, we present a solid silicon substrate functionalized with modified β-cyclodextrin monolayers as an optimal surface for organic contaminant uptake. The inclusion and capture of three potential pollutants, 4-chlorophenoxyacetic acid, 4-aminobenzoic acid and phenylethylamine, were studied. 1H-NMR and ROESY studies revealed the complete inclusion and details of the conformational orientation of the three guests in the per-(6-amino-6-deoxy)-β-cyclodextrin matrix, forming three new inclusion complexes that have not yet been reported. Capture assays for the guests were carried out by immersing the substrates in an aqueous pollutant solution and by measuring the UV\textendashvis spectra. This substrate showed a high sorption capacity at equilibrium, between 2.5 × 10−5 and 6.0 × 10−5 mmol/substrate, for the studied pollutants. In addition, this surface can be reused four times with an efficiency equal to the initial use. Therefore, it could be a versatile platform that could be applied for the capture of other organic pollutants from water.}, keywords = {activity, calculations, cyclodextrin, Surface Functionalized}, pubstate = {published}, tppubtype = {article} } In this work, we present a solid silicon substrate functionalized with modified β-cyclodextrin monolayers as an optimal surface for organic contaminant uptake. The inclusion and capture of three potential pollutants, 4-chlorophenoxyacetic acid, 4-aminobenzoic acid and phenylethylamine, were studied. 1H-NMR and ROESY studies revealed the complete inclusion and details of the conformational orientation of the three guests in the per-(6-amino-6-deoxy)-β-cyclodextrin matrix, forming three new inclusion complexes that have not yet been reported. Capture assays for the guests were carried out by immersing the substrates in an aqueous pollutant solution and by measuring the UV–vis spectra. This substrate showed a high sorption capacity at equilibrium, between 2.5 × 10−5 and 6.0 × 10−5 mmol/substrate, for the studied pollutants. In addition, this surface can be reused four times with an efficiency equal to the initial use. Therefore, it could be a versatile platform that could be applied for the capture of other organic pollutants from water. |
Pinto, C F; Torrico-Bazoberry, D; Flores-Prado, L; Bustamante, R O; Niemeyer, H M Demographic and Performance Effects of Alternative Host Use in a Neotropical Treehopper (Hemiptera: Membracidae) Artículo de revista Ecological Modelling, 416 , pp. 108905, 2020, ISSN: 0304-3800. Resumen | Enlaces | BibTeX | Etiquetas: Demography; Maternal care; Matrix models; Membracidae; Performance; Solanaceae; Yungas @article{RN78, title = {Demographic and Performance Effects of Alternative Host Use in a Neotropical Treehopper (Hemiptera: Membracidae)}, author = {C F Pinto and D Torrico-Bazoberry and L Flores-Prado and R O Bustamante and H.M. Niemeyer}, url = {http://www.sciencedirect.com/science/article/pii/S0304380019304132}, doi = {https://doi.org/10.1016/j.ecolmodel.2019.108905}, issn = {0304-3800}, year = {2020}, date = {2020-01-01}, journal = {Ecological Modelling}, volume = {416}, pages = {108905}, abstract = {The mechanisms which promote divergence in populations of phytophagous insects using alternative hosts depend on the characterization of hosts as different selective scenarios and the modeling of the demographic dynamics of the insect on those hosts. In the Bolivian Yungas forests, the treehopper Alchisme grossa (Hemiptera: Membracidae) utilizes two sympatric Solanaceae hosts, Brugmansia suaveolens and Solanum ursinum. On both hosts, females take care of nymphs during their development and adults use almost exclusively their natal host species. We characterized: 1) the performance of families (mother and nymphs) on both hosts, 2) maternal care across families and hosts, 3) biotic (herbivory, predators and parasites) and abiotic (temperature, relative humidity and luminosity) conditions across hosts and 4) demographic parameters of cohorts living under natural conditions on both hosts using matrix population modelling. The life cycle was longer on B. suaveolens than on S. ursinum. Microenvironmental abiotic and biotic traits differed between hosts. Nevertheless, performance did not differ between hosts and no differences between hosts were found in demographic parameters. None of the environmental variables explained the demographic parameters. Females performed maternal care with the same intensity on both hosts. Taken together with published data on the system, these results suggest that individuals of A. grossa in this study belong to a single population. Colonization of one of these hosts might be a recent event and evolutionary processes that promote ecological adaptation and hence demographic or performance differences have not yet become noticeable.}, keywords = {Demography; Maternal care; Matrix models; Membracidae; Performance; Solanaceae; Yungas}, pubstate = {published}, tppubtype = {article} } The mechanisms which promote divergence in populations of phytophagous insects using alternative hosts depend on the characterization of hosts as different selective scenarios and the modeling of the demographic dynamics of the insect on those hosts. In the Bolivian Yungas forests, the treehopper Alchisme grossa (Hemiptera: Membracidae) utilizes two sympatric Solanaceae hosts, Brugmansia suaveolens and Solanum ursinum. On both hosts, females take care of nymphs during their development and adults use almost exclusively their natal host species. We characterized: 1) the performance of families (mother and nymphs) on both hosts, 2) maternal care across families and hosts, 3) biotic (herbivory, predators and parasites) and abiotic (temperature, relative humidity and luminosity) conditions across hosts and 4) demographic parameters of cohorts living under natural conditions on both hosts using matrix population modelling. The life cycle was longer on B. suaveolens than on S. ursinum. Microenvironmental abiotic and biotic traits differed between hosts. Nevertheless, performance did not differ between hosts and no differences between hosts were found in demographic parameters. None of the environmental variables explained the demographic parameters. Females performed maternal care with the same intensity on both hosts. Taken together with published data on the system, these results suggest that individuals of A. grossa in this study belong to a single population. Colonization of one of these hosts might be a recent event and evolutionary processes that promote ecological adaptation and hence demographic or performance differences have not yet become noticeable. |
Núñez, A; Manzano, C A; Chi, C Health Outcomes, Utilization, and Equity in Chile: An Evolution from 1990 to 2015 and the Effects of the Last Health Reform Artículo de revista Public Health, 178 (9), pp. 38-48, 2020, ISSN: 0033-3506. Resumen | Enlaces | BibTeX | Etiquetas: access, chile, Concentration curves, Equity in health, Health reform, Nutrition @article{RN60, title = {Health Outcomes, Utilization, and Equity in Chile: An Evolution from 1990 to 2015 and the Effects of the Last Health Reform}, author = {A N\'{u}\~{n}ez and C A Manzano and C Chi}, url = {http://www.sciencedirect.com/science/article/pii/S003335061930277X}, doi = {https://doi.org/10.1016/j.puhe.2019.08.017}, issn = {0033-3506}, year = {2020}, date = {2020-01-01}, journal = {Public Health}, volume = {178}, number = {9}, pages = {38-48}, abstract = {Objective Chile is an attractive case study because of the deep political changes that it underwent over a short period of time: from a universal health service (60s), through a neoliberal reform (70s) and onto a series of legislative reforms (80s\textendash90s). This article aims to explore and assess the evolution of health outcomes, equity, and utilization in Chile through the last period of these reforms (1990\textendash2015). Study design Standardized health equity analysis. Methods We conducted a standardized economic analysis on health equity and healthcare utilization using the ADePT software (by the World Bank) and using data from the Chilean National Socio-economic Survey. We evaluated trends of health equity and examined concentration curves of health utilization of healthcare services and health outcomes such as children/elder/pregnant nutritional status, self-reported health, and physical limitations. Results Health outcomes such as nutritional problems in children and pregnant women were concentrated among the poor, while others such as high-relevance health conditions were similar for poorest and richest households. The concentration indexes for health outcomes suggested that income makes the distribution pro-poor. However, the opposite was true for age, in which the probability of health problems among rich individuals increased with age. The concentration curves for utilization of healthcare services showed that dental visits, laboratory exams, specialty visits, and hospitalizations were concentrated on the richest households, while the use of emergency services and preventive medicine were highly concentrated among poor individuals. Conclusions Although a positive trend in the increase of healthcare service use among income groups was observed, a significant impact of the latest health reform was not observed.}, keywords = {access, chile, Concentration curves, Equity in health, Health reform, Nutrition}, pubstate = {published}, tppubtype = {article} } Objective Chile is an attractive case study because of the deep political changes that it underwent over a short period of time: from a universal health service (60s), through a neoliberal reform (70s) and onto a series of legislative reforms (80s–90s). This article aims to explore and assess the evolution of health outcomes, equity, and utilization in Chile through the last period of these reforms (1990–2015). Study design Standardized health equity analysis. Methods We conducted a standardized economic analysis on health equity and healthcare utilization using the ADePT software (by the World Bank) and using data from the Chilean National Socio-economic Survey. We evaluated trends of health equity and examined concentration curves of health utilization of healthcare services and health outcomes such as children/elder/pregnant nutritional status, self-reported health, and physical limitations. Results Health outcomes such as nutritional problems in children and pregnant women were concentrated among the poor, while others such as high-relevance health conditions were similar for poorest and richest households. The concentration indexes for health outcomes suggested that income makes the distribution pro-poor. However, the opposite was true for age, in which the probability of health problems among rich individuals increased with age. The concentration curves for utilization of healthcare services showed that dental visits, laboratory exams, specialty visits, and hospitalizations were concentrated on the richest households, while the use of emergency services and preventive medicine were highly concentrated among poor individuals. Conclusions Although a positive trend in the increase of healthcare service use among income groups was observed, a significant impact of the latest health reform was not observed. |
2019 |
Gomez-Jeria, J S; Campos-Vallette, M; Carrasco-Flores, E A 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 , pp. 4622-4626, 2019, ISSN: 0717-9707. Resumen | Enlaces | BibTeX | Etiquetas: Archaeophilately, crocoite, fl-naphthol azopigments, forgery, German hyperinflation postage stamps, Prussian blue, Raman spectrum, XR, zinc oxide @article{RN1009, 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. Campos-Vallette and E.A. Carrasco-Flores}, url = {https://www.jcchems.com/index.php/JCCHEMS/article/view/937/347}, issn = {0717-9707}, year = {2019}, date = {2019-12-01}, journal = {Journal of the Chilean Chemical Society}, volume = {64}, pages = {4622-4626}, publisher = {Chilean Chemical Society}, abstract = {Colors of a collection set of postage stamps dated 1923 and corresponding to the hyperinflationary period of the German economy were identifiedwith Raman and X-ray fluorescence (XRF) spectroscopies. Molecular systems associated to the blue, green and yellow colours were characterized. Blue colour is Prussian blue (Fe4[Fe(CN)6]3) and the green colour resulted to be a combination of Prussian blue and the yellow/orange pigment (PbCrO4) or a yellow fl-naphthol like monoazopigment. The XRF data suggest that ZnO was used as filler..}, keywords = {Archaeophilately, crocoite, fl-naphthol azopigments, forgery, German hyperinflation postage stamps, Prussian blue, Raman spectrum, XR, zinc oxide}, pubstate = {published}, tppubtype = {article} } Colors of a collection set of postage stamps dated 1923 and corresponding to the hyperinflationary period of the German economy were identifiedwith Raman and X-ray fluorescence (XRF) spectroscopies. Molecular systems associated to the blue, green and yellow colours were characterized. Blue colour is Prussian blue (Fe4[Fe(CN)6]3) and the green colour resulted to be a combination of Prussian blue and the yellow/orange pigment (PbCrO4) or a yellow fl-naphthol like monoazopigment. The XRF data suggest that ZnO was used as filler.. |
Gomez-Jeria, J S Biology and Philosophy. VII. Sokrates, the Demigod Artículo de revista World Journal of Research and Review (WJRR), 9 (1), pp. 26-30, 2019, ISSN: 2455-3956. Resumen | Enlaces | BibTeX | Etiquetas: Apology, Cynicism, Delphi Oracle, Demigods, Plato, Pythia, Socrates, Socratic Schools, Sokrates, Xenophon. @article{RN1003, title = {Biology and Philosophy. VII. Sokrates, the Demigod}, author = {J.S. Gomez-Jeria}, url = {https://www.researchgate.net/publication/334282056_Biology_and_Philosophy_VII_Sokrates_the_Demigod}, doi = {https://doi.org/10.31871/WJRR.9.1.9}, issn = {2455-3956}, year = {2019}, date = {2019-07-01}, journal = {World Journal of Research and Review (WJRR)}, volume = {9}, number = {1}, pages = {26-30}, publisher = {Nextgen Research Publication}, abstract = {I use the cylinder-ladder model presented in the previous paper of this series to present and defend the thesis that Sokrates was placed in a step much higher than those that were occupied by almost all mortals regarding the degree of perception of reality and that he could perfectly be situated in the category of \"{e}demigod\'{i} as defined in this paper. Plato¥s Apology is considered the most probable and unique Sokratic-like text. Furthermore, I claim that Sokrates knew that he was (relatively) wiser than those around him due to its higher position on the cylinder-ladder. This last statement opens new questions about the response of the Pythia. Sokrates was clear that his discourse would be understood by his listeners accordingly to the place they occupied in the cylinder-ladder model. This is the reason because, after Sokrates death, so many different Socratic schools appeared. Finally, I firmly hold the idea that one day we will discover that our knowledge of Sokrates has not grown one iota since his death. Sokrates seems to be the first known Western stonecutter/ stonemason whose raw material is men.}, keywords = {Apology, Cynicism, Delphi Oracle, Demigods, Plato, Pythia, Socrates, Socratic Schools, Sokrates, Xenophon.}, pubstate = {published}, tppubtype = {article} } I use the cylinder-ladder model presented in the previous paper of this series to present and defend the thesis that Sokrates was placed in a step much higher than those that were occupied by almost all mortals regarding the degree of perception of reality and that he could perfectly be situated in the category of ëdemigodí as defined in this paper. Plato¥s Apology is considered the most probable and unique Sokratic-like text. Furthermore, I claim that Sokrates knew that he was (relatively) wiser than those around him due to its higher position on the cylinder-ladder. This last statement opens new questions about the response of the Pythia. Sokrates was clear that his discourse would be understood by his listeners accordingly to the place they occupied in the cylinder-ladder model. This is the reason because, after Sokrates death, so many different Socratic schools appeared. Finally, I firmly hold the idea that one day we will discover that our knowledge of Sokrates has not grown one iota since his death. Sokrates seems to be the first known Western stonecutter/ stonemason whose raw material is men. |
Gomez-Jeria, J S Biology and Philosophy. VI. Plato's Cave and Homo sapiens Inequality Artículo de revista World Journal of Research and Review (WJRR), 8 (6), pp. 23-29, 2019, ISSN: 2455-3956. Resumen | Enlaces | BibTeX | Etiquetas: Ancient rituals, Athens, Charles de Bovelles, DNA manipulation, enlightenments, Homo clausus, Julien Offray de La Mettrie, new Homo sapiens species., Platoís Cave, Racial State, Sparta @article{RN1002, title = {Biology and Philosophy. VI. Plato's Cave and Homo sapiens Inequality}, author = {J.S. Gomez-Jeria}, url = {https://www.researchgate.net/publication/334119165_Biology_and_Philosophy_VI_Platos_Cave_and_Homo_sapiens_Inequality}, doi = {https://doi.org/10.31871/WJRR.8.6.7}, issn = {2455-3956}, year = {2019}, date = {2019-06-01}, journal = {World Journal of Research and Review (WJRR)}, volume = {8}, number = {6}, pages = {23-29}, publisher = {Nextgen Research Publication}, abstract = {Plato\'{i}s Cave is presented and discussed considering it as a primary model to place man in the ladder of the degrees of apprehension of reality. A model constituted by a cylinder-ladder with steps is presented and discussed. The lowest level of this cylinder is filled with Homo sapiens having special characteristics. The people living inside Plato\'{i}s Cave fill the next segment of the cylinder. These people are well described in Charles de Bovelles\'{i} Liber de Sapiente. An individual placed on a certain step of this ladder is able to perceive the individuals placed on lower steps and may find an appropriate way to communicate with them. But he is not able to recognize individuals placed on steps above him, perceiving them at most as his equals. Also, an individual can ascend this ladder if and only if he has the genetic inheritance that allows him to do so. Also, he must find the appropriate method adapted to his genetics allowing him to climb. The cylinder-ladder model provides an interesting explanation of the results of the activity of preachers. It is necessary that Humanity be free definitively of all the elements that exist within Plato's Cave. This could be done when we have the complete knowledge of how to manipulate our DNA and thus be able to get rid of the trunk of the Primates and create one or more completely new species and not an \'{i}mproved' Homo sapiens. The necessity of finding the personal ontological status in the ladder should be an imperative for all.}, keywords = {Ancient rituals, Athens, Charles de Bovelles, DNA manipulation, enlightenments, Homo clausus, Julien Offray de La Mettrie, new Homo sapiens species., Plato\'{i}s Cave, Racial State, Sparta}, pubstate = {published}, tppubtype = {article} } Platoís Cave is presented and discussed considering it as a primary model to place man in the ladder of the degrees of apprehension of reality. A model constituted by a cylinder-ladder with steps is presented and discussed. The lowest level of this cylinder is filled with Homo sapiens having special characteristics. The people living inside Platoís Cave fill the next segment of the cylinder. These people are well described in Charles de Bovellesí Liber de Sapiente. An individual placed on a certain step of this ladder is able to perceive the individuals placed on lower steps and may find an appropriate way to communicate with them. But he is not able to recognize individuals placed on steps above him, perceiving them at most as his equals. Also, an individual can ascend this ladder if and only if he has the genetic inheritance that allows him to do so. Also, he must find the appropriate method adapted to his genetics allowing him to climb. The cylinder-ladder model provides an interesting explanation of the results of the activity of preachers. It is necessary that Humanity be free definitively of all the elements that exist within Plato's Cave. This could be done when we have the complete knowledge of how to manipulate our DNA and thus be able to get rid of the trunk of the Primates and create one or more completely new species and not an ímproved' Homo sapiens. The necessity of finding the personal ontological status in the ladder should be an imperative for all. |
Valencia-Gálvez, P; Peña, O; Moris, S; Barahona, P Raman Characterization of Cucr2-Xsnxs4 Spinels Artículo de revista Journal of the Chilean Chemical Society, 64 , pp. 4285-4289, 2019, ISBN: 0717-9707. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN32l, title = {Raman Characterization of Cucr2-Xsnxs4 Spinels}, author = {P Valencia-G\'{a}lvez and O Pe\~{n}a and S Moris and P Barahona}, url = {https://scielo.conicyt.cl/scielo.php?script=sci_arttext&pid=S0717-97072019000104285&nrm=iso}, isbn = {0717-9707}, year = {2019}, date = {2019-04-30}, journal = {Journal of the Chilean Chemical Society}, volume = {64}, pages = {4285-4289}, abstract = {Polycrystalline thiospinels CuCr2-xSnxS4 (x = 0.4, 0.8, 1.0 and 1.4) were synthesized via conventional solid-state reaction. The samples were characterized by powder X-ray diffraction (XRD), energy-dispersive X-ray analysis (SEM-EDS) and Raman spectroscopy. All the samples were indexed in the space group Fd3⎯⎯mFd3¯m. The Raman spectra confirmed the structure of normal spinel type with five characteristic signals for the active modes in Raman. Magnetic measurements, performed for the phases with x = 0.8 and 1.0, showed irreversible antiferromagnetism with dominant ferromagnetism and spin glass behavior.}, keywords = {}, pubstate = {published}, tppubtype = {article} } Polycrystalline thiospinels CuCr2-xSnxS4 (x = 0.4, 0.8, 1.0 and 1.4) were synthesized via conventional solid-state reaction. The samples were characterized by powder X-ray diffraction (XRD), energy-dispersive X-ray analysis (SEM-EDS) and Raman spectroscopy. All the samples were indexed in the space group Fd3⎯⎯mFd3¯m. The Raman spectra confirmed the structure of normal spinel type with five characteristic signals for the active modes in Raman. Magnetic measurements, performed for the phases with x = 0.8 and 1.0, showed irreversible antiferromagnetism with dominant ferromagnetism and spin glass behavior. |
Cabañas-García, E; Areche, C; Gómez-Aguirre, Y A; Jáuregui-Rincón, J; Cruz-Sosa, F; Pérez-Molphe-Balch, E Phytochemical Profile of Coryphantha Macromeris (Engelm.) Britton &Amp; Rose Cactaceae Obtained from in Vitro Culture Artículo de revista Revista Mexicana de Ingeniería Química, 19 (1), pp. 239-249, 2019. Resumen | Enlaces | BibTeX | Etiquetas: @article{RN9f, title = {Phytochemical Profile of Coryphantha Macromeris (Engelm.) Britton &Amp; Rose Cactaceae Obtained from in Vitro Culture}, author = {E Caba\~{n}as-Garc\'{i}a and C Areche and Y A G\'{o}mez-Aguirre and J J\'{a}uregui-Rinc\'{o}n and F Cruz-Sosa and E P\'{e}rez-Molphe-Balch}, url = {http://rmiq.org/ojs311/index.php/rmiq/article/view/540}, year = {2019}, date = {2019-04-30}, journal = {Revista Mexicana de Ingenier\'{i}a Qu\'{i}mica}, volume = {19}, number = {1}, pages = {239-249}, abstract = {In the last years, the demand for natural products has increased. Different cacti species has demonstrated to be a source for the biosynthesis of functional compounds, as is the case of Coryphantha macromeris (Engelm.) Britton & Rose. The aim of this work was to evaluate the capacity of C. macromeris growing under controlled in vitro conditions for the obtention of secondary metabolites. In vitro cultures of C. macromeris were established and then the phytochemical profile of aerial and root sections was analyzed by means of ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-PDA-HESI-Orbitrap-MS/MS). Under the proposed conditions, 44 metabolites were detected and 43 of them were identified; seven compounds are reported here for the first time for this cacti species. Organic acids (citric, gluconic and tianshic acids), and phenolic acids such as piscidic, ferulic and syringic acid and/or their derivatives were found as the metabolites with the highest relative abundance. Our results suggest that the in vitro culture of C. macromeris represents a potential source for the obtention of selected compounds, as well a useful system for future investigations related with the generation of root, callus and cell suspension cultures for the elicitation and study of high valuable metabolites.}, keywords = {}, pubstate = {published}, tppubtype = {article} } In the last years, the demand for natural products has increased. Different cacti species has demonstrated to be a source for the biosynthesis of functional compounds, as is the case of Coryphantha macromeris (Engelm.) Britton & Rose. The aim of this work was to evaluate the capacity of C. macromeris growing under controlled in vitro conditions for the obtention of secondary metabolites. In vitro cultures of C. macromeris were established and then the phytochemical profile of aerial and root sections was analyzed by means of ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-PDA-HESI-Orbitrap-MS/MS). Under the proposed conditions, 44 metabolites were detected and 43 of them were identified; seven compounds are reported here for the first time for this cacti species. Organic acids (citric, gluconic and tianshic acids), and phenolic acids such as piscidic, ferulic and syringic acid and/or their derivatives were found as the metabolites with the highest relative abundance. Our results suggest that the in vitro culture of C. macromeris represents a potential source for the obtention of selected compounds, as well a useful system for future investigations related with the generation of root, callus and cell suspension cultures for the elicitation and study of high valuable metabolites. |
Kpotin, G A; Bede, Lucie A; Houngue-Kpota, A; Anatovi, W; Kuevi, U A; Atohoun, G S; Mensah, J -B; Gomez-Jeria, J S; Badaw, M Relationship between electronic structures and antiplasmodial activities of xanthone derivatives: a 2D-QSAR approach Artículo de revista Structural Chemistry, 30 , pp. 2301-2310, 2019, ISSN: 1572-9001. Resumen | Enlaces | BibTeX | Etiquetas: Xanthone Antiplasmodial QSAR DFT Klopman-Peradejordi-Gomez approach Malaria @article{RN1010, title = {Relationship between electronic structures and antiplasmodial activities of xanthone derivatives: a 2D-QSAR approach}, author = {G.A. Kpotin and A. Lucie Bede and A. Houngue-Kpota and W. Anatovi and U.A. Kuevi and G.S. Atohoun and J.-B. Mensah and J.S. Gomez-Jeria and M. Badaw}, url = {https://link.springer.com/article/10.1007/s11224-019-01333-w}, doi = {https://doi.org/10.1007/s11224-019-01333-w}, issn = {1572-9001}, year = {2019}, date = {2019-01-12}, journal = {Structural Chemistry}, volume = {30}, pages = {2301-2310}, publisher = {Springer}, abstract = {Malaria is an important disease causing many death in several countries of Africa and Asia. In these continents, some plants such as Garcinia cola are used to fight against this disease because they contain xanthone derivatives which present antiplasmodial activity. The present theoretical study aims to establish a relationship between the electronic structure and the antiplasmodial activity of some xanthone derivatives, and more specifically to build a 2D-pharmacophore model in order to predict the biological activity of xanthone derivatives. The calculations are performed within the density functional theory (DFT) using the B3LYP/6-31G(d,p) level of theory. The developed approach quantitative structure-activity relationship (QSAR) follows the Klopman-Peradejordi-Gomez (KPG) methodology. We obtain a statistically significant equation relating the variation of the logarithm of half maximal inhibitory concentration (log(IC50)) with the variation of the numerical values of a set of eight local atomic reactivity descriptors (R?=?0.98, R2?=?0.97, adj-R2?=?0.95, F(8.13)?=?48.63, p? keywords = {Xanthone Antiplasmodial QSAR DFT Klopman-Peradejordi-Gomez approach Malaria}, pubstate = {published}, tppubtype = {article} } Malaria is an important disease causing many death in several countries of Africa and Asia. In these continents, some plants such as Garcinia cola are used to fight against this disease because they contain xanthone derivatives which present antiplasmodial activity. The present theoretical study aims to establish a relationship between the electronic structure and the antiplasmodial activity of some xanthone derivatives, and more specifically to build a 2D-pharmacophore model in order to predict the biological activity of xanthone derivatives. The calculations are performed within the density functional theory (DFT) using the B3LYP/6-31G(d,p) level of theory. The developed approach quantitative structure-activity relationship (QSAR) follows the Klopman-Peradejordi-Gomez (KPG) methodology. We obtain a statistically significant equation relating the variation of the logarithm of half maximal inhibitory concentration (log(IC50)) with the variation of the numerical values of a set of eight local atomic reactivity descriptors (R?=?0.98, R2?=?0.97, adj-R2?=?0.95, F(8.13)?=?48.63, p?<?0.00000, SD 0.08). The antiplasmodial activity seems to be driven by atomic orbitals and charges. Our 2D-pharmacophore model should be useful to propose new xanthone derivatives with higher antiplasmodial activity. |
Gomez-Jeria, J S; Kpotin, G A A Density Functional Theory Analysis of the relationships between electronic structure and KCNQ2 potassium channels inhibition by a series of retigabine derivatives Artículo de revista Chemistry Research Journal, 4 , pp. 68-79, 2019, ISSN: 2455-8990. Resumen | Enlaces | BibTeX | Etiquetas: dft, KCNQ2 potassium channels, KPG method, local atomic reactivity indices, local molecular orbitals., molecular electrostatic potential, qsar, Retigabine @article{RN1006, title = {A Density Functional Theory Analysis of the relationships between electronic structure and KCNQ2 potassium channels inhibition by a series of retigabine derivatives}, author = {J.S. Gomez-Jeria and G.A. Kpotin}, url = {https://www.researchgate.net/publication/328582641_A_density_Functional_Analysis_of_the_relationships_between_electronic_structure_and_KCNQ2_potassium_channels_inhibition_by_a_series_of_retigabine_derivatives}, issn = {2455-8990}, year = {2019}, date = {2019-01-12}, journal = {Chemistry Research Journal}, volume = {4}, pages = {68-79}, publisher = {Leon Publications}, abstract = {A quantum-chemical analysis of the relationships between electronic structure and KCNQ2 potassium channels inhibition was carried out for a group of retigabine derivatives. For the quantitative structure-activity relationship (QSAR) investigation, we have employed the Klopman-Peradejordi-Gomez formal method. A statistically significant equation, relating the variation of the inhibitory capacity to the variation of the numerical value of several local atomic reactivity indices was found. The mechanism of action is orbital-controlled. The obtained results allowed building the partial 2D pharmacophore that should be useful to design new derivatives with enhanced inhibitory capacity.}, keywords = {dft, KCNQ2 potassium channels, KPG method, local atomic reactivity indices, local molecular orbitals., molecular electrostatic potential, qsar, Retigabine}, pubstate = {published}, tppubtype = {article} } A quantum-chemical analysis of the relationships between electronic structure and KCNQ2 potassium channels inhibition was carried out for a group of retigabine derivatives. For the quantitative structure-activity relationship (QSAR) investigation, we have employed the Klopman-Peradejordi-Gomez formal method. A statistically significant equation, relating the variation of the inhibitory capacity to the variation of the numerical value of several local atomic reactivity indices was found. The mechanism of action is orbital-controlled. The obtained results allowed building the partial 2D pharmacophore that should be useful to design new derivatives with enhanced inhibitory capacity. |
Gomez-Jeria, J S; Contreras-Lira, V Chemistry Research Journal, 4 , pp. 34-45, 2019, ISSN: 2455-8990. Resumen | Enlaces | BibTeX | Etiquetas: Aurora kinase A, common skeleton, dft, electronic structure, epidermal growth factor receptor kinase, Klopman-Peradejordi-Gomez method., KPG model, pharmacophore, qsar @article{RN1005, title = {A DFT analysis of the relationships between electronic structure and inhibition of aurora kinase A and epidermal growth factor receptor kinase by a set of N4-phenyl substituted-7H-pyrrolo[2,3-d]pyrimidin-4-amines}, author = {J.S. Gomez-Jeria and V. Contreras-Lira}, url = {https://www.researchgate.net/publication/336684277_A_DFT_analysis_of_the_relationships_between_electronic_structure_and_inhibition_of_aurora_kinase_A_and_epidermal_growth_factor_receptor_kinase_by_a_set_of_N_4_-phenyl_substituted-7H-pyrrolo23-dpyrimid}, issn = {2455-8990}, year = {2019}, date = {2019-01-10}, journal = {Chemistry Research Journal}, volume = {4}, pages = {34-45}, publisher = {Leon Publications}, abstract = {A quantum-chemical structure-activity study is carried out for the inhibition of aurora kinase A and epidermal growth factor receptor kinase by a group of N4-phenylsubstituted-7H-pyrrolo[2,3-d]pyrimidin-4-amines. The Klopman-Peradejordi-Gomez method was employed. Statistically significant relationships between the variation of the inhibitory capacity of a group of N4-phenylsubstituted-7H-pyrrolo[2,3-d]pyrimidin-4-amines against aurora kinase A and epidermal growth factor receptor kinase and the variation of the values of several local atomic reactivity indices were obtained. The results are presented in the form of a partial pharmacophore that could be useful in the synthesis of new and more powerful molecules.}, keywords = {Aurora kinase A, common skeleton, dft, electronic structure, epidermal growth factor receptor kinase, Klopman-Peradejordi-Gomez method., KPG model, pharmacophore, qsar}, pubstate = {published}, tppubtype = {article} } A quantum-chemical structure-activity study is carried out for the inhibition of aurora kinase A and epidermal growth factor receptor kinase by a group of N4-phenylsubstituted-7H-pyrrolo[2,3-d]pyrimidin-4-amines. The Klopman-Peradejordi-Gomez method was employed. Statistically significant relationships between the variation of the inhibitory capacity of a group of N4-phenylsubstituted-7H-pyrrolo[2,3-d]pyrimidin-4-amines against aurora kinase A and epidermal growth factor receptor kinase and the variation of the values of several local atomic reactivity indices were obtained. The results are presented in the form of a partial pharmacophore that could be useful in the synthesis of new and more powerful molecules. |
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