Tailoring the oxidation state of cobalt through halide functionality in sol-gel silica

The functionality or oxidation state of cobalt within a silica matrix can be tailored through the use of cationic surfactants and their halide counter ions during the sol-gel synthesis. Simply by adding surfactant we could significantly increase the amount of cobalt existing as Co3O4 within the silica from 44% to 77%, without varying the cobalt precursor concentration. However, once the surfactant to cobalt ratio exceeded 1, further addition resulted in an inhibitory mechanism whereby the altered pyrolysis of the surfactant decreased Co3O4 production. These findings have significant implications for the production of cobalt/silica composites where maximizing the functional Co3O4 phase remains the goal for a broad range of catalytic, sensing and materials applications

Infrared Ellipsometry Analysis of Heritage Photographic Prints

[EN] Focusing on the photographic archive of Julian Carrillo (Mexico), we study and characterize the photographic processes of a set of 13 photographs dated between 1884 and 1925. By using infrared spectroscopic ellipsometry, we classified a selected set of photographs according to its kind of binder. Thus, we recognized for each photograph, the presence of proteins, and therefore, the particular photographic process. Furthermore, we have identified the presence of baryta layer, the use of plasticizer, and the eventual coating utilized to protect the photograph, whose composition was based in natural organic components, mainly shellac, beeswax, or camphorNieto-Villena, A.; Martinez, JR.; Flores-Camacho, JM.; Lastras-Martinez, A.; De La Cruz-Mendoza, JA.; Ortega-Zarzosa, G.; Valcarcel Andrés, JC.... (2018). Infrared Ellipsometry Analysis of Heritage Photographic Prints. Studies in Conservation. 63(8):466-476. https://doi.org/10.1080/00393630.2018.1476962S466476638Brambilla, L., Riedo, C., Baraldi, C., Nevin, A., Gamberini, M. C., D’Andrea, C., … Toniolo, L. (2011). Characterization of fresh and aged natural ingredients used in historical ointments by molecular spectroscopic techniques: IR, Raman and fluorescence. Analytical and Bioanalytical Chemistry, 401(6), 1827-1837. doi:10.1007/s00216-011-5168-zCasoli, A., & Fornaciari, S. (2014). An analytical study on an early twentieth-century Italian photographs collection by means of microscopic and spectroscopic techniques. Microchemical Journal, 116, 24-30. doi:10.1016/j.microc.2014.04.003Cattaneo, B., Chelazzi, D., Giorgi, R., Serena, T., Merlo, C., & Baglioni, P. (2008). Physico-chemical characterization and conservation issues of photographs dated between 1890 and 1910. Journal of Cultural Heritage, 9(3), 277-284. doi:10.1016/j.culher.2008.01.004Daher, C., Paris, C., Le Hô, A.-S., Bellot-Gurlet, L., & Échard, J.-P. (2010). A joint use of Raman and infrared spectroscopies for the identification of natural organic media used in ancient varnishes. Journal of Raman Spectroscopy, 41(11), 1494-1499. doi:10.1002/jrs.2693Edwards, H. G. M., Farwell, D. W., & Daffner, L. (1996). Fourier-transform Raman spectroscopic study of natural waxes and resins. I. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 52(12), 1639-1648. doi:10.1016/0584-8539(96)01730-8Fujiwara, H. (2007). Spectroscopic Ellipsometry. doi:10.1002/9780470060193Hendriks, K., & Ross, L. (1988). Chemical Treatments of Discoloured Photographic Prints: Image Manipulation or Legitimate Restoration? The Journal of Photographic Science, 36(3), 132-132. doi:10.1080/00223638.1988.11736990Mallégol, J., Gardette, J.-L., & Lemaire, J. (2000). Long-term behavior of oil-based varnishes and paints. Photo- and thermooxidation of cured linseed oil. Journal of the American Oil Chemists’ Society, 77(3), 257-263. doi:10.1007/s11746-000-0042-4Nieto-Villena, A., Martínez, J. R., de la Cruz-Mendoza, J. A., Valcárcel-Andrés, J. C., Ortega-Zarzosa, G., Solbes-García, Á., & Vázquez-Martínez, E. (2018). Atomic force microscopy as a tool for binder identification in ancient photographic processes. Surface and Interface Analysis, 50(4), 496-505. doi:10.1002/sia.6408Ostroff, Eugene. 1966. “Restoration of Photographs by Neutron Activation.” Science 154 (3745): 119–123. http://science.sciencemag.org/content/154/3745/119.Othmer, Kirk, ed. 2005. Encyclopedia of Chemical Technology. Vol. 17, 5th ed. New York: Wiley.Ricci, C., Bloxham, S., & Kazarian, S. G. (2007). ATR-FTIR imaging of albumen photographic prints. Journal of Cultural Heritage, 8(4), 387-395. doi:10.1016/j.culher.2007.07.002Sifontes, Á. B., Cañizales, E., Toro-Mendoza, J., Ávila, E., Hernández, P., Delgado, B. A., … Cruz-Barrios, E. (2015). Obtaining Highly Crystalline Barium Sulphate Nanoparticles via Chemical Precipitation and Quenching in Absence of Polymer Stabilizers. Journal of Nanomaterials, 2015, 1-8. doi:10.1155/2015/510376Stulik, Dusan, Herant Khanjian, Alberto de Tagle, and Alexandra M. Botelho. 2002. “Investigation of Jean-Louis-Marie-Eugene Durieu’s Toning and Varnishing Experiments: A Non-Destructive Approach.” ICOM Committee for Conservation 13th Triennial Meeting, Río de Janeiro, 658–663.Price, Beth A., and Boris Pretzel, eds. 2009. Infrared and Raman Users Group Spectral Database. 2007 ed. Vol. 1 & 2. Philadelphia: IRUG. Accessed June 20, 2014. http://www.irug.org/.Vila, A., & Centeno, S. A. (2013). FTIR, Raman and XRF identification of the image materials in turn of the 20th century pigment-based photographs. Microchemical Journal, 106, 255-262. doi:10.1016/j.microc.2012.07.01

Dietary α‐Linolenic Acid, Marine ω‐3 Fatty Acids, and Mortality in a Population With High Fish Consumption: Findings From the PREvención con DIeta MEDiterránea (PREDIMED) Study

Background: Epidemiological evidence suggests a cardioprotective role of α‐linolenic acid (ALA), a plant‐derived ω‐3 fatty acid. It is unclear whether ALA is beneficial in a background of high marine ω‐3 fatty acids (long‐chain n‐3 polyunsaturated fatty acids) intake. In persons at high cardiovascular risk from Spain, a country in which fish consumption is customarily high, we investigated whether meeting the International Society for the Study of Fatty Acids and Lipids recommendation for dietary ALA (0.7% of total energy) at baseline was related to all‐cause and cardiovascular disease mortality. We also examined the effect of meeting the society's recommendation for long‐chain n‐3 polyunsaturated fatty acids (≥500 mg/day). Methods and Results: We longitudinally evaluated 7202 participants in the PREvención con DIeta MEDiterránea (PREDIMED) trial. Multivariable‐adjusted Cox regression models were fitted to estimate hazard ratios. ALA intake correlated to walnut consumption (r=0.94). During a 5.9‐y follow‐up, 431 deaths occurred (104 cardiovascular disease, 55 coronary heart disease, 32 sudden cardiac death, 25 stroke). The hazard ratios for meeting ALA recommendation (n=1615, 22.4%) were 0.72 (95% CI 0.56–0.92) for all‐cause mortality and 0.95 (95% CI 0.58–1.57) for fatal cardiovascular disease. The hazard ratios for meeting the recommendation for long‐chain n‐3 polyunsaturated fatty acids (n=5452, 75.7%) were 0.84 (95% CI 0.67–1.05) for all‐cause mortality, 0.61 (95% CI 0.39–0.96) for fatal cardiovascular disease, 0.54 (95% CI 0.29–0.99) for fatal coronary heart disease, and 0.49 (95% CI 0.22–1.01) for sudden cardiac death. The highest reduction in all‐cause mortality occurred in participants meeting both recommendations (hazard ratio 0.63 [95% CI 0.45–0.87]). Conclusions: In participants without prior cardiovascular disease and high fish consumption, dietary ALA, supplied mainly by walnuts and olive oil, relates inversely to all‐cause mortality, whereas protection from cardiac mortality is limited to fish‐derived long‐chain n‐3 polyunsaturated fatty acids. Clinical Trial Registration URL: http://www.Controlled-trials.com/. Unique identifier: ISRCTN35739639

Influencia en el aprendizaje de los alumnos usando simuladores de física

We analyze the influence of using simulators in the learning of then students as a tool of didactic interest in the field of physics. The simalators or Applets that we use in this work were made in the Science Faculty of the UASLP, and, in its firts stage, we use 18 simulators in Windows ambient that treat some subjects of general physics. This set of simulators are disigned in such a way that they can be contrast with real experiments and/or used associated with them, that facilitate a good variety of forms for didactic design. The system is based in the idea of learning exploring in the learning process of diverse stages. The use of the simulator system in a regular physics course, lead to an increment of 15% to 82% in the number of approved students.Se analiza la influencia que sobre el aprendizaje de los alumnos produce la utilización de simuladores como herramienta de un indudable interés didáctico en el campo de la Física. Los simuladores o applets que se utilizan en este trabajo fueron desarrollados en la Facultad de Ciencias de la UASLP y, en su primera etapa, utilizan 18 simuladores en ambiente windows que tratan diversos temas de física general. Este sistema de simuladores está diseñado de tal manera que pueden contrastarse con experimentos reales y/o utilizarse de manera conjunta, lo que posibilita una buena variedad de formas para el diseño didáctico. El sistema se fundamenta en la idea de aprender explorando, en el proceso de aprendizaje disponiendo de varios escenarios. La utilización del sistema de simuladores en un curso regular de física produjo un aumento del 15% al 82% en el número de alumnos aprobados

Preparation and Characterization of Nickel Ferrite-SiO 2

Magnetic composites with silver nanoparticles bonded to their surface were successfully prepared using a simple chemical method. By means of a sol-gel technique, nickel ferrite nanoparticles have been prepared and coated with silica to control and avoid their magnetic agglomeration. The structural and magnetic properties of the nanoparticles were studied in function of the annealing temperature. Then, silver nanoparticles were incorporated by hydrolysis-condensation of tetraethyl orthosilicate, which contains silver nitrate on the surface of the nickel ferrite-SiO2 core/shell. Samples were characterized using X-ray diffraction, IR spectroscopy, SEM, and magnetometry. Results show that the silica covered the nickel ferrite nanoparticles and the silver nanoparticles remain stable in the surface of the composite

Coesite Formation at Ambient Pressure and Low Temperatures

Partial crystallization of silica xerogel in the form of coesite has been obtained at low-pressure conditions and temperatures of ∼565∘C, in samples containing chlorophyll aggregates dispersed in amorphous silica. Silica xerogel samples were prepared by the sol-gel method using an ethanol:H2O:TEOS molar ratio of 4:11.6:1 and loaded with extracts from frozen spinach leaves. The silica xerogel microstructure of the powders was studied as a function of annealing temperature. It was found that partial crystallization of the glass matrix in the form of coestite was obtained at lower pressure than those specified by the phase diagram. Chlorophyll aggregates were added to the starting solutions which, upon thermal treatments, form small colloidal particles in the glass matrix. The presence of coesite is corroborated by the Rietveld refinement method

Structural Effects of Heat-Treated Silica Xerogel Induced by Incorporation of Chlorophyll Species

Composites containing chlorophyll aggregates dispersed in amorphous silica are of interest because of their optical attractive properties. The silica powders added with chlorophyll species, prepared by the sol-gel method, were studied using X-ray diffraction, IR spectroscopy and differential temperature analysis. Silica xerogel samples were prepared using an ethanol/H2O/TEOS molar ratio of 4:11.6:1 and loaded with extracts from frozen spinach leaves. The silica xerogel microstructure of the powders was studied as a function of the annealing temperature. We found in our samples partial crystallization of the glass matrix in form of tridymite and cristobalite phases and quenching centers or nonfluorescing aggregates due to denaturation of photosystem promoted by chlorophyll decomposition after 400∘C

Atomic force microscopy as a tool for binder identification in ancient photographic processes

[EN] Focusing in the photographic archive of Julian Carrillo (Mexico), a microstructural analysis of surface photography was carried on to prove the feasibility of atomic force microscopy to identify the binder used in the manufactured ancient photography. It has been identified 2 structural groups in which known binders may be classified, one of them is associated with gelatin and the other one to albumen and collodion. The former group present a higher roughness values than the second one, being able to identify the binder by means of its morphology aspect related with the width of linear traces. From the obtained results, it has been observed that atomic force microscopy is a very good technique to properly identify the binder used in a photograph according to the surface morphology and roughness values.Nieto-Villena, A.; Martinez, JR.; De La Cruz-Mendoza, JA.; Valcarcel Andrés, JC.; Ortega-Zarzosa, G.; Solbes-Garcia, A.; Vazquez-Martinez, E. (2018). Atomic force microscopy as a tool for binder identification in ancient photographic processes. Surface and Interface Analysis. 50(4):496-505. https://doi.org/10.1002/sia.6408S496505504Pereira, C., Ferreira, I. M. P. L. V. O., Branco, L. C., Sandu, I. C. A., & Busani, T. (2013). Atomic Force Microscopy as a Valuable Tool in an Innovative Multi-scale and Multi-technique Non-invasive Approach to Surface Cleaning Monitoring. Procedia Chemistry, 8, 258-268. doi:10.1016/j.proche.2013.03.032Sandu, I. C. A., Busani, T., & de Sá, M. H. (2011). The surface behavior of gilding layer imitations on polychrome artefacts of cultural heritage. Surface and Interface Analysis, 43(8), 1171-1181. doi:10.1002/sia.3796Lobefaro M Sandu I Authentic versus faked iconography: a study on the behaviour of painting materials 2008 64Aucouturier, M., & Darque-Ceretti, E. (2007). The surface of cultural heritage artefacts: physicochemical investigations for their knowledge and their conservation. Chemical Society Reviews, 36(10), 1605. doi:10.1039/b605304cEzrati J-J Two non-invasive techniques for the study of the surface of cultural heritage objects: Optical measurement of micro-roughness and backscattering spectro-colorimetry Proceedings of Art2008-9th International Conference on NDT of Art 2008Schiavon, G., Kuchler, J. G., Corain, B., & Hiller, W. (2001). Force Modulation Atomic Force Microscopy as a Powerful Tool in Organic-Inorganic Hybrid Materials Analysis. Advanced Materials, 13(5), 310-313. doi:10.1002/1521-4095(200103)13:53.0.co;2-cGarcía-Heras, M., Carmona, N., Ruiz-Conde, A., Sánchez-Soto, P., & Benítez, J. J. (2005). Application of atomic force microscopy to the study of glass decay. Materials Characterization, 55(4-5), 272-280. doi:10.1016/j.matchar.2005.07.001Casoli, A., & Fornaciari, S. (2014). An analytical study on an early twentieth-century Italian photographs collection by means of microscopic and spectroscopic techniques. Microchemical Journal, 116, 24-30. doi:10.1016/j.microc.2014.04.003Centeno, S. A., Vila, A., & Barro, L. (2014). Characterization of unprocessed historic platinum photographic papers by Raman, FTIR and XRF. Microchemical Journal, 114, 8-15. doi:10.1016/j.microc.2013.11.016Vila, A., & Centeno, S. A. (2013). FTIR, Raman and XRF identification of the image materials in turn of the 20th century pigment-based photographs. Microchemical Journal, 106, 255-262. doi:10.1016/j.microc.2012.07.016Ioanid, E. G., Ioanid, A., Rusu, D. E., Popescu, C.-M., & Stoica, I. (2011). Surface changes upon high-frequency plasma treatment of heritage photographs. Journal of Cultural Heritage, 12(4), 399-407. doi:10.1016/j.culher.2011.04.002Christensen MC FT-IR techniques for studying the composition and degradation of photographic materials 2007 1 14Čechák, T., Kopecká, I., Trojek, T., Štanzel, T., & Bártová, H. (2015). Application of X-ray fluorescence in an investigation of photographic heritage. Radiation Physics and Chemistry, 116, 8-13. doi:10.1016/j.radphyschem.2015.05.015Modica, A., Alberghina, M. F., Brai, M., Bruno, M., Di Bella, M., Fontana, D., & Tranchina, L. (2017). XRF analysis to identify historical photographic processes: The case of some Interguglielmi Jr.’s images from the Palermo Municipal Archive. Radiation Physics and Chemistry, 135, 76-80. doi:10.1016/j.radphyschem.2017.02.026Kontturi, E., Thüne, P. C., Alexeev, A., & Niemantsverdriet, J. W. (2005). Introducing open films of nanosized cellulose—atomic force microscopy and quantification of morphology. Polymer, 46(10), 3307-3317. doi:10.1016/j.polymer.2005.02.087Baker, A. A., Helbert, W., Sugiyama, J., & Miles, M. J. (2000). New Insight into Cellulose Structure by Atomic Force Microscopy Shows the Iα Crystal Phase at Near-Atomic Resolution. Biophysical Journal, 79(2), 1139-1145. doi:10.1016/s0006-3495(00)76367-3Reilly JM Severson DG Mccabe C Image deterioration in albumen photographic prints 1982 61 65Messier, P., & Vitale, T. (1994). Effects of Aqueous Treatment on Albumen Photographs. Journal of the American Institute for Conservation, 33(3), 257. doi:10.2307/3179637Vitale, T., & Messier, P. (1994). Physical and Mechanical Properties of Albumen Photographs. Journal of the American Institute for Conservation, 33(3), 279. doi:10.2307/3179638Messier, P., & Vitale, T. (1993). Cracking in albumen photographs: An ESEM investigation. Microscopy Research and Technique, 25(5-6), 374-383. doi:10.1002/jemt.1070250505Ricci, C., Bloxham, S., & Kazarian, S. G. (2007). ATR-FTIR imaging of albumen photographic prints. Journal of Cultural Heritage, 8(4), 387-395. doi:10.1016/j.culher.2007.07.002Stulik DC Kaplan A The atlas of analytical signatures of photographic processes 2013 www.getty.edu/conservationSifontes, Á. B., Cañizales, E., Toro-Mendoza, J., Ávila, E., Hernández, P., Delgado, B. A., … Cruz-Barrios, E. (2015). Obtaining Highly Crystalline Barium Sulphate Nanoparticles via Chemical Precipitation and Quenching in Absence of Polymer Stabilizers. Journal of Nanomaterials, 2015, 1-8. doi:10.1155/2015/510376Cattaneo, B., Chelazzi, D., Giorgi, R., Serena, T., Merlo, C., & Baglioni, P. (2008). Physico-chemical characterization and conservation issues of photographs dated between 1890 and 1910. Journal of Cultural Heritage, 9(3), 277-284. doi:10.1016/j.culher.2008.01.00