A Kinetic Model Considering Catalyst Deactivation for Methanol-to-Dimethyl Ether on a Biomass-Derived Zr/P-Carbon Catalyst

A Zr-loaded P-containing biomass-derived activated carbon (ACPZr) has been tested for methanol dehydration between 450 and 550 °C. At earlier stages, methanol conversion was complete, and the reaction product was mainly dimethyl ether (DME), although coke, methane, hydrogen and CO were also observed to a lesser extent. The catalyst was slowly deactivated with time-on-stream (TOS), but maintained a high selectivity to DME (>80%), with a higher yield to this product than 20% for more than 24 h at 500 °C. A kinetic model was developed for methanol dehydration reaction, which included the effect of the inhibition of water and the deactivation of the catalyst by coke. The study of stoichiometric rates pointed out that coke could be produced through a formaldehyde intermediate, which might, alternatively, decompose into CO and H2. On the other hand, the presence of 10% water in the feed did not affect the rate of coke formation, but produced a reduction of 50% in the DME yield, suggesting a reversible competitive adsorption of water. A Langmuir–Hinshelwood reaction mechanism was used to develop a kinetic model that considered the deactivation of the catalyst. Activation energy values of 65 and 51 kJ/mol were obtained for DME and methane production in the temperature range from 450 °C to 550 °C. On the other hand, coke formation as a function of time on stream (TOS) was also modelled and used as the input for the deactivation function of the model, which allowed for the successful prediction of the DME, CH4 and CO yields in the whole evaluated TOS interval.This research was supported by the Spanish Ministry of Science, Innovation and Universities and Junta de Andalucia through RTI2018-097555-B-I00 and UMA18-FEDERJA-110 projects, respectively. J.T.-L. also acknowledges the assistance of the Spanish Ministry of Economy, Industry and Competitiveness for the award of a predoctoral contract to become a Ph.D. (BES-2016-079237). Partial funding for open access charge: Universidad de Málag

Hydroxychloroquine in the treatment of COVID-19 disease: a systematic review and meta-analysis

BACKGROUND Given the urgency of finding a specific treatment for coronavirus disease 2019 (COVID-19), several approaches have been carried out, including the use of chloroquine (CQ) and hydroxychloroquine (HCQ). This study was aimed to systematically evaluate the available evidence on the effectiveness of HCQ in the treatment of COVID-19 disease. METHODS We searched 3 databases (PubMed, Google Scholar, and ClinicalTrials) until May 31, 2020 for clinical studies in patients diagnosed with COVID-19 comparing conventional treatment with and without HCQ combined with or without azithromycin. The risk of bias assessment and quality evaluation was carried out according to the Cochrane recommendations. RESULTS 5 articles (1 randomized clinical trial [RCT], 1 non-RCT, and 3 cohort studies) were included. The main outcome measure in 2 articles was the virological conversion determined by reverse transcription-polymerase chain reaction; however, the findings of both studies were contrary. The main objective of the other studies was to determine the effects of HCQ on COVID-19 mortality, and the studies showed similar results. In general, the studies showed methodological limitations, risk of bias, and variable quality. A meta-analysis from 2,041 patients showed the odds ratio of mortality for patients having HCQ and standard care was 1.38 (95% CI 0.93–2.04). CONCLUSIONS Considering the limited data available and the very low-to-moderate quality of the studies included in this systematic review, the evidence suggests that the HCQ administration does not decrease the risk of death from COVID-19

Fenómenos físicos de las nanopartículas de oro

El oro ha sido uno de los materiales más preciados por el hombre desde la antigüedad por sus excelentes propiedades, entre las que destaca su hermoso color y brillo, su maleabilidad y su estabilidad química. En las últimas décadas, el interés por este material se ha incrementado al encontrar que el oro en forma de nanopartículas presenta fenómenos físicos nuevos que incrementan su potencial tecnológico. En esta contribución presentamos una breve descripción de algunos de estos fenómenos, los cuales son objeto de estudio del cuerpo académico física de los sistemas de baja dimensionalidad y sus aplicaciones de la FCFM de la UANL

Un procedimiento de búsqueda voraz adaptativo probabilista para un problema monoproducto de localización de instalaciones no capacitado

AbstractThis paper considers the three-echelon uncapacitated facility location problem (TUFLP), which consists on both defining the flow of products from manufacturing plants to clients via a set of warehouses and the location of such warehouses. The objective function is to minimize the total cost of warehouse location and production and distribution. Since the problem is NP-hard, this paper proposes a Greedy Randomized Search Procedure (GRASP) to solve the single-item case. Computational experiments are conducted using known instances from the literature. Results show that the proposed algorithm performs well obtaining very good solutions (and even optimal values) in less computational time than an exact method based on mixed-integer linear programming.ResumenEste artículo considera el problema de localización de instalaciones no capacitado en una cadena logística de tres eslabones (Three-echelon Uncapacitated Facility Location Problem, TUFLP). El problema de optimización consiste en definir los flujos de productos desde las plantas de manufactura hacia los clientes a través de centros de distribución (CD), cuya ubicación debe determinarse adicionalmente. La función objetivo es la minimización del costo total conformado por el costo fijo de localización de los centros de distribución y los costos variables de producción y distribución de productos. Puesto que este es un problema NP-completo, se propone la utilización de un procedimiento voraz adaptativo probabilista (GRASP) para resolver el caso particular monoproducto. Se desarrollan experimentos computacionales con instancias conocidas en la literatura.Los resultados muestran que el algoritmo propuesto permite obtener buenas soluciones (e incluso valores óptimos) en menor tiempo de cálculo que un procedimiento exacto basado en programación lineal entera mixta

[Reported prevalence of dental caries in Mexican children and teenagers]

Abstract Dental caries is a serious multifactorial oral disease that causes demineralization of the tooth’s hard tissues and affects more than half of the world's population. The objective of this exploratory systematic review was to determine the prevalence of dental caries in Mexican children and adolescents, as well as related factors such as sex, nutritional status, type of dentition, education, living conditions, socioeconomic level, and the type of demographic area. The eligibility criteria to be considered were observational studies whose sample included Mexicans 0-15 years of age in which the prevalence or an index of dental caries had been evaluated. Eligible studies were identified through the search carried out in 6 databases and manual search, without publication time restriction. Fifty-four studies were found that met the eligibility criteria. In these included studies it was observed that, in the last decades, the prevalence of caries in Mexican children and adolescents exhibits a tendency to decrease this disease. In the 1980s, caries prevalences of up to 92.8% were reported; between 1990-1999, the highest reported prevalence was 97%; from 2000-2009, the highest reported prevalence was 95%; from 2010 to 2019 the highest prevalence was 94.6%; and from 2020 and 2021, prevalences of up to 88.5% were reported. Although there has been a decrease in the prevalence of caries in Mexican children, this disease continues to be linked to biological, behavioral and socioeconomic determinants. Resumen La caries dental es una enfermedad bucodental multifactorial grave que provoca la desmineralización de los tejidos duros del diente y afecta a más de la mitad de la población mundial. El objetivo de esta revisión sistemática exploratoria fue determinar la prevalencia de caries dental en niños y adolescentes mexicanos, así como los factores relacionados como el sexo, el estado nutricional, el tipo de dentición, la educación, las condiciones de vida, el nivel socioeconómico y el tipo de área demográfica. Los criterios de elegibilidad fueron estudios observacionales cuya muestra incluyera mexicanos de 0 a 15 años en los que se hubiera evaluado la prevalencia o un índice de caries dental. Los estudios elegibles fueron identificados mediante la búsqueda realizada en 6 bases de datos y de manera manual, sin restricción de tiempo de publicación. Se encontraron 54 estudios que cumplieron con los criterios de elegibilidad. En estos estudios incluidos se observó que en las últimas décadas la prevalencia de caries en niños y adolescentes mexicanos exhibe una tendencia a la baja. En la década de 1980, se reportaron prevalencias de caries de hasta 92.8%; entre 1990-1999, la mayor prevalencia reportada fue de 97%; de 2000-2009, la prevalencia más alta reportada fue de 95%; de 2010 a 2019 la mayor prevalencia fue de 94.6%; y de 2020 y 2021, se reportaron prevalencias de hasta 88.5%. Aunque ha habido un decremento en la prevalencia de caries en niños mexicanos, esta enfermedad continúa vinculada a determinantes biológicas, conductuales y socioeconómicas

Clasificación del género de peatones y conductores basada en su comportamiento en la vía pública

Los accidentes vehiculares representan un problema de salud pública a nivel mundial, los traumatismos por accidentes de tránsito son la primera causa de muerte en niños y adultos jóvenes. En México, a través de la estadística de accidentes elaborada por el Instituto Nacional de Estadística y Geografía se logra tener un panorama de los accidentes viales en el ámbito nacional, así como las consecuencias humanas y materiales que conlleva. Sin embargo, no se tiene a detalle cuáles fueron los factores o comportamientos de los peatones o conductores, que contribuyeron a que el accidente ocurriera. En este artículo, se presenta la clasificación del género basado en el comportamiento que los actores viales, peatón y conductor, exhiben dentro de la vía pública. Para ello, se usa el algoritmo J48 que proporciona árboles de decisión que permiten examinar el conocimiento adquirido. El mejor clasificador de género, para los peatones obtuvo un 71.61% de acierto usando validación cruzada de 5 pliegues. De los 13 atributos, solo se utilizan 6 para la clasificación en el árbol de decisión, dando lugar a 7 reglas, 3 para la clase masculina y 4 para la femenina. En el caso de los conductores, el mejor clasificador obtuvo un 73.39% de acierto, pero lo logra a costa de la clase femenino. En ambos actores viales, los atributos que proporcionan más información para la separación de las clases son cruzar o conducir bajo los efectos del alcohol y conducir cansado

Electrical Stimulation at the ST36 Acupoint Protects against Sepsis Lethality and Reduces Serum TNF Levels through Vagus Nerve- and Catecholamine-Dependent Mechanisms

Electrical vagus nerve (VN) stimulation during sepsis attenuates tumor necrosis factor (TNF) production through the cholinergic anti-inflammatory pathway, which depends on the integrity of the VN and catecholamine production. To characterize the effect of electroacupuncture at ST36 (EA-ST36) on serum TNF, IL-6, nitrite, and HMGB1 levels and survival rates, based on VN integrity and catecholamine production, a sepsis model was induced in rats using cecal ligation and puncture (CLP). The septic rats were subsequently treated with EA-ST36 (CLP+ST36), and serum samples were collected and analyzed for cytokines levels. The serum TNF, IL-6, nitrite, and HMGB1 levels in the CLP+ST36 group were significantly lower compared with the group without treatment, the survival rates were significantly higher (P<0.05), and the acute organ injury induced by CLP was mitigated by EA-ST36; however, when subdiaphragmatic vagotomy was performed, the serum levels of TNF in the CLP+ST36 group did not show a significant difference compared with the group without electrostimulation, and, similarly, no significant difference in serum TNF levels was found under the pharmacological blockade of catecholamines. These results suggest that in rats with CLP sepsis models EA-ST36 reduces serum TNF levels through VN- and atecholamine-dependent mechanisms

Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

Role of age and comorbidities in mortality of patients with infective endocarditis

[Purpose]: The aim of this study was to analyse the characteristics of patients with IE in three groups of age and to assess the ability of age and the Charlson Comorbidity Index (CCI) to predict mortality. [Methods]: Prospective cohort study of all patients with IE included in the GAMES Spanish database between 2008 and 2015.Patients were stratified into three age groups:<65 years,65 to 80 years,and ≥ 80 years.The area under the receiver-operating characteristic (AUROC) curve was calculated to quantify the diagnostic accuracy of the CCI to predict mortality risk. [Results]: A total of 3120 patients with IE (1327 < 65 years;1291 65-80 years;502 ≥ 80 years) were enrolled.Fever and heart failure were the most common presentations of IE, with no differences among age groups.Patients ≥80 years who underwent surgery were significantly lower compared with other age groups (14.3%,65 years; 20.5%,65-79 years; 31.3%,≥80 years). In-hospital mortality was lower in the <65-year group (20.3%,<65 years;30.1%,65-79 years;34.7%,≥80 years;p < 0.001) as well as 1-year mortality (3.2%, <65 years; 5.5%, 65-80 years;7.6%,≥80 years; p = 0.003).Independent predictors of mortality were age ≥ 80 years (hazard ratio [HR]:2.78;95% confidence interval [CI]:2.32–3.34), CCI ≥ 3 (HR:1.62; 95% CI:1.39–1.88),and non-performed surgery (HR:1.64;95% CI:11.16–1.58).When the three age groups were compared,the AUROC curve for CCI was significantly larger for patients aged <65 years(p < 0.001) for both in-hospital and 1-year mortality. [Conclusion]: There were no differences in the clinical presentation of IE between the groups. Age ≥ 80 years, high comorbidity (measured by CCI),and non-performance of surgery were independent predictors of mortality in patients with IE.CCI could help to identify those patients with IE and surgical indication who present a lower risk of in-hospital and 1-year mortality after surgery, especially in the <65-year group

Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe