2016 |
Ruiz-Fernandez, A; Lopez-Cascales, J J; Giner-Casares, J J; Araya-Maturana, R; Diaz-Banose, F G; Munoz-Gacitua, D; Weiss-Lopez, B Effect of Shape and Bending Modulus on the Properties of Nematic Lyotropic Liquid Crystals Artículo de revista Rsc Advances, 6 (9), pp. 7455-7464, 2016. Resumen | Enlaces | BibTeX | Etiquetas: bilayers, carbon ewald, h-2 lubrication, macromolecules, matter, mesh molecular-dynamics nanotubes, particle rigidity, simulations, systems @article{RN324, title = {Effect of Shape and Bending Modulus on the Properties of Nematic Lyotropic Liquid Crystals}, author = { A. Ruiz-Fernandez and J.J. Lopez-Cascales and J.J. Giner-Casares and R. Araya-Maturana and F.G. Diaz-Banose and D. Munoz-Gacitua and B. Weiss-Lopez}, url = {/brokenurl#<Go to ISI>://WOS:000369515500071}, doi = {10.1039/c5ra24019k}, year = {2016}, date = {2016-01-01}, journal = {Rsc Advances}, volume = {6}, number = {9}, pages = {7455-7464}, abstract = {Synovial liquid is a natural lubricant of articular joints, such as shoulders, knees and hips. Thus, the development of biocompatible lubricants that can be employed in medical prosthesis for artificial implants, and eventually in certain therapies against osteo-arthritis or rheumatoid-arthritis diseases, is of an undoubted importance. Lyotropic liquid crystals have been used in the synthesis of silica and metals containing regularly oriented nanoporous, to obtain oriented carbon nanotube materials, in several pharmaceutical applications, as membrane mimetics and in lubrication applications. In this context, a new nematic lyotropic liquid crystal has been developed based on tetradecyltrimethyl ammonium chloride (TTAC), decanol (DeOH), a natural mixture of lipids (PL) extracted from soybean and sodium chloride (NaCl), all dissolved in water. A 30% w/w increase in TTAC content respect a certain composition of reference produces a more than 24-fold increase in the macroscopic viscosity of the solution. To understand the molecular principles that explain this behavior, several experimental and theoretical studies have been carried out. In this regard, H-2-NMR quadrupole splittings of fully deuterated sodium dodecyl sulphate (SDS-d(25)) introduced as molecular probe, transmission electron microscopy (TEM), freeze fracture transmission electron microscopy (FF-TEM), cryogenic transmission electron microscopy (Cryo-TEM) and polarized light microscopy (PLM) were obtained. In addition, hydrodynamic studies determined how the enhancement in viscosity requires a change in the shape of the aggregate, from circular to elliptic. Finally, molecular dynamics simulations allowed to estimate how variations in the bending modulus, k(b), can explain the observed tendency of the quadrupole splittings, on the basis of a modification in the flexibility of the aggregate.}, keywords = {bilayers, carbon ewald, h-2 lubrication, macromolecules, matter, mesh molecular-dynamics nanotubes, particle rigidity, simulations, systems}, pubstate = {published}, tppubtype = {article} } Synovial liquid is a natural lubricant of articular joints, such as shoulders, knees and hips. Thus, the development of biocompatible lubricants that can be employed in medical prosthesis for artificial implants, and eventually in certain therapies against osteo-arthritis or rheumatoid-arthritis diseases, is of an undoubted importance. Lyotropic liquid crystals have been used in the synthesis of silica and metals containing regularly oriented nanoporous, to obtain oriented carbon nanotube materials, in several pharmaceutical applications, as membrane mimetics and in lubrication applications. In this context, a new nematic lyotropic liquid crystal has been developed based on tetradecyltrimethyl ammonium chloride (TTAC), decanol (DeOH), a natural mixture of lipids (PL) extracted from soybean and sodium chloride (NaCl), all dissolved in water. A 30% w/w increase in TTAC content respect a certain composition of reference produces a more than 24-fold increase in the macroscopic viscosity of the solution. To understand the molecular principles that explain this behavior, several experimental and theoretical studies have been carried out. In this regard, H-2-NMR quadrupole splittings of fully deuterated sodium dodecyl sulphate (SDS-d(25)) introduced as molecular probe, transmission electron microscopy (TEM), freeze fracture transmission electron microscopy (FF-TEM), cryogenic transmission electron microscopy (Cryo-TEM) and polarized light microscopy (PLM) were obtained. In addition, hydrodynamic studies determined how the enhancement in viscosity requires a change in the shape of the aggregate, from circular to elliptic. Finally, molecular dynamics simulations allowed to estimate how variations in the bending modulus, k(b), can explain the observed tendency of the quadrupole splittings, on the basis of a modification in the flexibility of the aggregate. |
2015 |
Toro, A R; Campos, C; Molina, C; Morales, R G E; Leiva, M A Accuracy and Reliability of Chile's National Air Quality Information System for Measuring Particulate Matter: Beta Attenuation Monitoring Issue Artículo de revista Environment International, 82 , pp. 101-109, 2015, ISSN: 0160-4120. Resumen | Enlaces | BibTeX | Etiquetas: environmental chemistry, matter, megacities, model, monitoring, network, particulate pm10 pollution, quality santiago, system, temuco @article{RN270, title = {Accuracy and Reliability of Chile's National Air Quality Information System for Measuring Particulate Matter: Beta Attenuation Monitoring Issue}, author = { A.R. Toro and C. Campos and C. Molina and R.G.E. Morales and M.A. Leiva}, url = {/brokenurl#<Go to ISI>://WOS:000357909800013}, doi = {10.1016/j.envint.2015.02.009}, issn = {0160-4120}, year = {2015}, date = {2015-01-01}, journal = {Environment International}, volume = {82}, pages = {101-109}, publisher = {2015 Elsevier Ltd.}, abstract = {A critical analysis of Chile's National Air Quality Information System (NAQIS) is presented, focusing on particulate matter (PM) measurement. This paper examines the complexity, availability and reliability of monitoring station information, the implementation of control systems, the quality assurance protocols of the monitoring station data and the reliability of the measurement systems in areas highly polluted by particulate matter. From information available on the NAQIS website, it is possible to confirm that the PM2.5 (PM10) data available on the site correspond to 30.8% (69.2%) of the total information available from the monitoring stations. There is a lack of information regarding the measurement systems used to quantify air pollutants, most of the available data registers contain gaps, almost all of the information is categorized as "preliminary information" and neither standard operating procedures (operational and validation) nor assurance audits or quality control of the measurements are reported. In contrast, events that cause saturation of the monitoring detectors located in northern and southern Chile have been observed using beta attenuation monitoring. In these cases, it can only be concluded that the PM content is equal to or greater than the saturation concentration registered by the monitors and that the air quality indexes obtained from these measurements are underestimated. This occurrence has been observed in 12 (20) public and private stations where PM2.5 (PM10) is measured. The shortcomings of the NAQIS data have important repercussions for the conclusions obtained from the data and for how the data are used. However, these issues represent opportunities for improving the system to widen its use, incorporate comparison protocols between equipment install new stations and standardize the control system and quality assurance.}, keywords = {environmental chemistry, matter, megacities, model, monitoring, network, particulate pm10 pollution, quality santiago, system, temuco}, pubstate = {published}, tppubtype = {article} } A critical analysis of Chile's National Air Quality Information System (NAQIS) is presented, focusing on particulate matter (PM) measurement. This paper examines the complexity, availability and reliability of monitoring station information, the implementation of control systems, the quality assurance protocols of the monitoring station data and the reliability of the measurement systems in areas highly polluted by particulate matter. From information available on the NAQIS website, it is possible to confirm that the PM2.5 (PM10) data available on the site correspond to 30.8% (69.2%) of the total information available from the monitoring stations. There is a lack of information regarding the measurement systems used to quantify air pollutants, most of the available data registers contain gaps, almost all of the information is categorized as "preliminary information" and neither standard operating procedures (operational and validation) nor assurance audits or quality control of the measurements are reported. In contrast, events that cause saturation of the monitoring detectors located in northern and southern Chile have been observed using beta attenuation monitoring. In these cases, it can only be concluded that the PM content is equal to or greater than the saturation concentration registered by the monitors and that the air quality indexes obtained from these measurements are underestimated. This occurrence has been observed in 12 (20) public and private stations where PM2.5 (PM10) is measured. The shortcomings of the NAQIS data have important repercussions for the conclusions obtained from the data and for how the data are used. However, these issues represent opportunities for improving the system to widen its use, incorporate comparison protocols between equipment install new stations and standardize the control system and quality assurance. |
2016 |
Effect of Shape and Bending Modulus on the Properties of Nematic Lyotropic Liquid Crystals Artículo de revista Rsc Advances, 6 (9), pp. 7455-7464, 2016. |
2015 |
Accuracy and Reliability of Chile's National Air Quality Information System for Measuring Particulate Matter: Beta Attenuation Monitoring Issue Artículo de revista Environment International, 82 , pp. 101-109, 2015, ISSN: 0160-4120. |