Repositorio académico de acceso abierto (Univ. Autonóma de Chile)
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Accurate ab initio spectroscopic studies of promising interstellar ethanolamine iminic precursors
No full textContext. The detection of NH2CH2CH2OH (ethanolamine) in molecular cloud G+0.693-0.027 adds an additional player to the pre-biotic molecules discovered so far in the interstellar medium (ISM). As this molecule might be formed through condensed-phase hydrogenation steps, detecting one or more of the molecules involved might help to elucidate the chemical pathway leading to its production. Aims. The chemical path involves the formation of four chemical species. In this work, we study the energies of the isomers involved, indicate the best candidates for detection purposes, and provide the distortion constants of the most energetically favoured isomers undetected so far. Methods. We used highly accurate CCSD(T)-F12/cc-pCVTZ-F12 computations to predict the lowest energy isomers as well as their spectroscopic constants, taking corrections for core electron correlation and scalar relativity into account. Results. We studied 14 isomers. We find that the lowest energy isomer proposed in previous studies is not the actual minimum. We provide a set of rotational and distortion constants of the two new most stable isomers together with their fundamental vibrational frequencies in order to guide the search for these important astrochemical precursors of prebiotic molecules in the ISM. © 2024 EDP Sciences. All rights reserved.Universidad Autónoma de Chil
Real-world effectiveness and safety of erenumab for the treatment of migraine: A systematic review and meta-analysis
No full textBackground: Migraine is a common and disabling primary headache disorder. Several drugs targeting calcitonin gene-related peptide (CGRP), such as erenumab (an anti-CGRP receptor mAb), have been developed recently. However, the real-world effects of erenumab are not well understood. Objective: To assess the clinical effectiveness and safety of erenumab for reducing migraine intensity and frequency in the real world. Methods: A systematic search of PubMed, Scopus, Web of Science and the Cochrane Library was conducted from inception to December 2023. Studies estimating the real-world effect of erenumab on monthly migraine days (MMD), monthly headache days (MHD), headache impact test (HIT-6), number of days in medication (NDM), acute monthly intake (AMI), pain intensity (PI) and safety outcomes were included. Meta-analyses of proportions or mean differences were performed. Results: Fifty-three studies were included. At 3-months, the effect was −7.18 days for MMD, −6.89 days for MHD, −6.97 for HIT-6, -6.22 days for NDM, −15.75 for AMI, and −1.71 for PI. Generally, the effect at 6- and 12-months increased slightly and gradually. The MMD/MHD response rates revealed that approximately one-third of patients exhibited a response greater than 30%, while one-sixth demonstrated a response exceeding 50%. Additionally, 3–4% of patients achieved a response rate of 100%. Adverse event rates were 0.34 and 0.43 at 6- and 12-months, respectively. Conclusion: This study provides strong evidence of the effectiveness and safety of erenumab in the real world; to our knowledge, this is the first real-world meta-analysis specific to erenumab. Erenumab represents a solid therapeutic option for physicians. © 2024 Elsevier B.V.Universidad de Castilla-La Mancha, UCLM, (2022-PROD-20657); Universidad de Castilla-La Mancha, UCLM; Ministerio de Ciencia, Innovación y Universidades, MCIU, (FPU21/06866); Ministerio de Ciencia, Innovación y Universidades, MCI
Solubility of Methane in Ionic Liquids for Gas Removal Processes Using a Single Multilayer Perceptron Model
No full textIn this work, four hundred and forty experimental solubility data points of 14 systems composed of methane and ionic liquids are considered to train a multilayer perceptron model. The main objective is to propose a simple procedure for the prediction of methane solubility in ionic liquids. Eight machine learning algorithms are tested to determine the appropriate model, and architectures composed of one input layer, two hidden layers, and one output layer are analyzed. The input variables of an artificial neural network are the experimental temperature (T) and pressure (P), the critical properties of temperature (Tc) and pressure (Pc), and the acentric (ω) and compressibility (Zc) factors. The findings show that a (4,4,4,1) architecture with the combination of T-P-Tc-Pc variables results in a simple 45-parameter model with an absolute prediction deviation of less than 12%. © 2024 by the authors.Agencia Nacional de Investigación y Desarrollo, ANID, (21171075, DIUA 238-2022); VRID, (VRID 19011062-INV); DIUA, (238-2022)Universidad Autónoma de ChileVicerrectoría de Investigación y Doctorad
Subnational atomization as a factor of increasing corruption in Venezuela
No full textThis mixed-method research is based on the general proposition that the greater the number of subnational jurisdictions relative to the population and the greater the number of vertical tiers of government, the greater the incentives for corruption. The specific focus is on the atomization of subnational governments and the creation of community councils as two factors of flawed political decentralization that are linked to increased corruption in Venezuela. The propositions are tested using fieldwork analysis on three subnational units of governance in Venezuela and multivariate statistical tests against a wide range of controls on 100 randomly selected countries
Capital Intelectual y Universidades de Chile, un Modelo Teórico
No full textEl conocimiento se ha transformado en un activo corporativo, uno de los más importantes y la base principal para desarrollar una ventaja competitiva. El capital intelectual nos ayuda a medir los niveles de conocimiento y los intangibles acumulados por las empresas. Las universidades son un caso particular. Sabemos que son intensivas en conocimiento, lo que nos entrega un terreno fértil para el desarrollo y medición del capital intelectual. No obstante, pocos modelos consideran las particularidades de este tipo de instituciones. Considerando lo anterior, este trabajo propone un modelo de capital intelectual que vincula las áreas de desarrollo de la academia con los componentes del capital intelectual, incorporando los dos niveles de desarrollo del conocimiento: explícito e implícito. 
DESEMPEÑO DE AYUNTAMIENTOS TÍPICO Y ATÍPICO EN EL MUNICIPIO MEXICANO. UN ESTUDIO DE CASO: ANÁLISIS INSTITUCIONAL Y DE REDES
No full textEn condiciones ordinarias, el funcionamiento del gobierno municipal mexicano obedece a la lógica centralista-presidencialista. En pocas ocasiones, este sistema ha sido alterado generando cabildos municipales (ayuntamientos) “atípicos”. Estos casos de excepción, constituyen objeto de interés y son fuente de información sobre la construcción de acuerdos y toma de decisiones gubernamentales, atendiendo el principio de “racionalidad limitada”, que escapa a la práctica centralista. Un ejemplo puntual es el ayuntamiento de Mazatlán 2002-2004. Las reflexiones que aquí se presentan aportan conocimiento acerca del desempeño de un gobierno de partido minoritario en un entorno partidista adverso y de la dinámica institucional entre una planilla-concejo2 y un presidente municipal de diferente filiación política. La metodología aplicada se apoya en el análisis institucional y de redes
Tumor mutational burden predictability in head and neck squamous cell carcinoma patients treated with immunotherapy: systematic review and meta-analysis
No full textBACKGROUND: Tumor mutational burden (TMB) has been demonstrated to predict the response to immune checkpoint inhibitors (ICIs) in various cancers. However, the role of TMB in head and neck squamous cell carcinoma (HNSCC) has not yet been specifically addressed. Since HNSCC patients exhibit a rather limited response to ICIs, there is an unmet need to develop predictive biomarkers to improve patient selection criteria and the clinical benefit of ICI treatment. METHODS: We conducted a systematic review and meta-analysis according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) reporting guidelines. HNSCC cohort studies were selected when TMB prior to ICI treatment was evaluated, TMB cutoff value was available, and the prognostic value of TMB was evaluated by time-to-event survival analysis. A total of 11 out of 1960 articles were analyzed, including 1200 HNSCC patients. RESULTS: The results showed that those patients harboring high TMB exhibited a significantly superior overall response rate (OR = 2.62; 95% CI 1.74-3.94; p < 0.0001) and a survival advantage (HR = 0.53; 95% CI 0.39-0.71; p < 0.0001) after ICI treatment. CONCLUSION: This is the first meta-analysis to demonstrate a higher response and clinical benefit from ICI therapy in HNSCC patients with high TMB. © 2024. The Author(s).Universidad Autónoma de Chil
Superoxide dismutase 2 deficiency is associated with enhanced central chemoreception in mice: Implications for breathing regulation
No full textAims: In mammals, central chemoreception plays a crucial role in the regulation of breathing function in both health and disease conditions. Recently, a correlation between high levels of superoxide anion (O2.-) in the Retrotrapezoid nucleus (RTN), a main brain chemoreceptor area, and enhanced central chemoreception has been found in rodents. Interestingly, deficiency in superoxide dismutase 2 (SOD2) expression, a pivotal antioxidant enzyme, has been linked to the development/progression of several diseases. Despite, the contribution of SOD2 on O2.- regulation on central chemoreceptor function is unknown. Accordingly, we sought to determine the impact of partial deletion of SOD2 expression on i) O2.−accumulation in the RTN, ii) central ventilatory chemoreflex function, and iii) disordered-breathing. Finally, we study cellular localization of SOD2 in the RTN of healthy mice. Methods: Central chemoreflex drive and breathing function were assessed in freely moving heterozygous SOD2 knockout mice (SOD2+/− mice) and age-matched control wild type (WT) mice by whole-body plethysmography. O2.- levels were determined in RTN brainstem sections and brain isolated mitochondria, while SOD2 protein expression and tissue localization were determined by immunoblot, RNAseq and immunofluorescent staining, respectively. Results: Our results showed that SOD2+/− mice displayed reductions in SOD2 levels and high O2.- formation and mitochondrial dysfunction within the RTN compared to WT. Additionally, SOD2+/− mice displayed a heightened ventilatory response to hypercapnia and exhibited overt signs of altered breathing patterns. Both, RNAseq analysis and immunofluorescence co-localization studies showed that SOD2 expression was confined to RTN astrocytes but not to RTN chemoreceptor neurons. Finally, we found that SOD2+/− mice displayed alterations in RTN astrocyte morphology compared to RTN astrocytes from WT mice. Innovation & conclusion: These findings provide first evidence of the role of SOD2 in the regulation of O2.- levels in the RTN and its potential contribution on the regulation of central chemoreflex function. Our results suggest that reductions in the expression of SOD2 in the brain may contribute to increase O2.- levels in the RTN being the outcome a chronic surge in central chemoreflex drive and the development/maintenance of altered breathing patterns. Overall, dysregulation of SOD2 and the resulting increase in O2.- levels in brainstem respiratory areas can disrupt normal respiratory control mechanisms and contribute to breathing dysfunction seen in certain disease conditions characterized by high oxidative stress. © 2023Universidad Autónoma de Chil
Esthetic Rehabilitation with Lithium Disilicate Veneers
No full textBecause the aesthetic results and preservation of tooth structure, lithium disilicate veneers are indicated for the aesthetic treatment of anterior teeth with abnormal shape, size and color. The aim of this report was to demonstrate the steps in oral rehabilitation using lithium disilicate veneers. The patient had teeth diastemas from 15 to 25; gene- ral and oral clinical examination was performed, and study models were obtained. waxed diagnosis was made based on the DSD and Mockup was drawn with addition silicone; the laboratory fabricate veneers lithium disilicate were cemented by adhesive technique. Veneers allowed a conservative, functional and aesthetic rehabilitation treatment of our patient
Detritus y producción industrial en el territorio de reciclaje. Análisis de la intermediación en el sur del conurbano bonaerense.
No full textEste artículo tiene como objetivo hacer una aproximación comprensiva a las especificidades y el rol que cumplen los depósitos o intermedierios y sus proveedores en el circuito de reciclaje. Se realiza un primer acercamiento a la diversidad de los actores de este subsistema económico a partir de la construcción de una tipología como herramienta útil para ordenar y ponderar una realidad económica y social compleja. Este trabajo presenta los resultados del análisis de los registros comerciales de un depósito ubicado en Don Bosco, Partido de Quilmes de la Provincia de Buenos Aires (Argentina), que se complementa con entrevistas y visitas realizadas a actores claves