Impact of Low-Temperature Water Exposure and Removal on Zeolite HY.

Aqueous-phase postsynthetic modifications of the industrially important Y-type zeolite are commonly used to change overall acid site concentrations, introduce stabilizing rare-earth cations, impart bifunctional character through metal cation exchange, and tailor the distribution of Brønsted and Lewis acid sites. Zeolite Y is known to undergo framework degradation in the presence of both vapor- and liquid-phase water at temperatures exceeding 100 °C, and rare-earth exchanged and stabilized HY catalysts are commonly used for fluidized catalytic cracking due to their increased hydrothermal resilience. Here, using detailed spectroscopy, crystallography, and flow-reactor experiments, we reveal unexpected decreases in Brønsted acid site (BAS) density for zeolite HY following exposure even to room-temperature liquid water. These data indicate that aqueous-phase ion-exchange procedures commonly used to modify zeolite Y are impacted by the liquid water and its removal, even when fractional heating rates and inert conditions much less severe than standard practice are used for catalyst dehydration. X-ray diffraction, thermogravimetric, and spectroscopic analyses reveal that the majority of framework degradation occurs during the removal of a strongly bound water fraction in HY, which does not form when NH4Y is immersed in liquid water and which leads to reduced acidity in HY even when dehydration conditions much milder than those typically practiced are employed. Na+-exchanged HY prepared via room-temperature aqueous dissolution demonstrates that Brønsted acid sites are lost in excess of the theoretical maximum that is possible from sodium titration. The structural impact of low-temperature aqueous-phase ion-exchange methods complicates the interpretation of subsequent data and likely explains the wide variation in reported acid site concentrations and catalytic activity of HY zeolites with high-Al content.

Síntomas depresivos y prevalencia de fragilidad en adultos mayores colombianos. Análisis secundario de la encuesta SABE Colombia 2015

Objetivo: Analizar la relación entre los síntomas depresivos y la prevalencia de fragilidad medida como fenotipo de fragilidad. Materiales y métodos: Estudio secundario de la encuesta SABE Colombia 2015. Se utilizaron las puntuaciones de la escala Yesavage como variable independiente, la prevalencia de fragilidad calculada con el fenotipo de fragilidad de Fried. Realizamos un análisis descriptivo y bivariado de la muestra, seguido de un análisis multivariado ajustando por variables de confusión. Resultados: Analizamos información de un total de 19 004 participantes mayores de 60 años, participantes sin deterioro cognitivo de la encuesta, a quienes se les administró la escala Yesavage. La media de edad fue 69.25 años, el 56 % de los participantes eran mujeres, la prevalencia de fragilidad fue del 12 % y se encontró síntomas depresivos en 57,4 % de la muestra. En el análisis multivariado encontramos asociaciones estadísticamente significativas entre las puntuaciones más altas de la escala Yesavage y la presencia de fragilidad (Yesavage 5-10) OR 1.20 (0.98-1.46) p valor 0.066 y (Yesavage >10) 2.05 (1.46-2.89) <0.001 después de ajustar por edad, sexo, comorbilidades, funcionalidad, escolaridad y estado marital Conclusiones: Nuestro estudio muestra asociaciones estadísticamente significativas entre la presencia de síntomas depresivos medidos con la escala Yesavage y la prevalencia de fragilidad según el índice de Fried. Aunque existe escasa evidencia en cuanto a la asociación de estas dos entidades en Latinoamérica, nuestros resultados son consistentes con estudios previos en la región.

Objetive: There is scarce evidence in Latin America that describes depression in the elderly population with fragility. The aim of this paper is to provide a better understanding of the relationship between depressive symptoms in elderly and the prevalence of frailty. Material and methods: We performed secondary analysis of the SABE Colombia 2015 survey. The Yesavage scale scores were used as an independent variable, the prevalence of frailty was estimated with the Fried fragility phenotype. We performed a descriptive and bivariate analysis of the sample, followed by a multivariate analysis adjusting for confounding variables. Results: We analyzed information from a total of 19,004 participants over 60 years of age, participants without cognitive impairment of the survey, who were administered the Yes-avage scale. The mean age was 69.25 years, 56 % of the participants were women, the prevalence of frailty was 12 % and depressive symptoms were found in 57.4 % of the sample. In the multivariate analysis we found statistically significant associations between frailty and the higher Yesavage scores (score 5-10) OR 1.20 (0.98-1.46) p valor 0.066 and (score> 10) 2.05 (1.46-2.89) <0.001 after adjusting for age, sex, comorbidities, functionality, schooling and marital status. Conclusions: Our study shows an independent relationship between depressive symptoms and frailty phenotype in the SABE Colombia 2015s survey There is lack of data and characterization of this population in Latin America regarding the relationship of these conditions, however our results are consistent with previous reports from this region.

Design, Screening, and Testing of Non-Rational Peptide Libraries with Antimicrobial Activity: In Silico and Experimental Approaches.

One of the challenges of modern biotechnology is to find new routes to mitigate the resistance to conventional antibiotics. Antimicrobial peptides (AMPs) are an alternative type of biomolecules, naturally present in a wide variety of organisms, with the capacity to overcome the current microorganism resistance threat. Here, we reviewed our recent efforts to develop a new library of non-rationally produced AMPs that relies on bacterial genome inherent diversity and compared it with rationally designed libraries. Our approach is based on a four-stage workflow process that incorporates the interplay of recent developments in four major emerging technologies: artificial intelligence, molecular dynamics, surface-display in microorganisms, and microfluidics. Implementing this framework is challenging because to obtain reliable results, the in silico algorithms to search for candidate AMPs need to overcome issues of the state-of-the-art approaches that limit the possibilities for multi-space data distribution analyses in extremely large databases. We expect to tackle this challenge by using a recently developed classification algorithm based on deep learning models that rely on convolutional layers and gated recurrent units. This will be complemented by carefully tailored molecular dynamics simulations to elucidate specific interactions with lipid bilayers. Candidate AMPs will be recombinantly-expressed on the surface of microorganisms for further screening via different droplet-based microfluidic-based strategies to identify AMPs with the desired lytic abilities. We believe that the proposed approach opens opportunities for searching and screening bioactive peptides for other applications.

Identification of active sites on supported metal catalysts with carbon nanotube hydrogen highways.

Catalysts consisting of metal particles supported on reducible oxides exhibit promising activity and selectivity for a variety of current and emerging industrial processes. Enhanced catalytic activity can arise from direct contact between the support and the metal or from metal-induced promoter effects on the oxide. Discovering the source of enhanced catalytic activity and selectivity is challenging, with conflicting arguments often presented based on indirect evidence. Here, we separate the metal from the support by a controlled distance while maintaining the ability to promote defects via the use of carbon nanotube hydrogen highways. As illustrative cases, we use this approach to show that the selective transformation of furfural to methylfuran over Pd/TiO2 occurs at the Pd-TiO2 interface while anisole conversion to phenol and cresol over Cu/TiO2 is facilitated by exposed Ti3+ cations on the support. This approach can be used to clarify many conflicting arguments in the literature.