An original (beta+gamma)-TiNbTa material was manufactured by an optimised powder metallurgy treatment, based on a mechanical alloying (MA) synthesis, carried out at low energy, and a subsequently ...field assisted consolidation technique, the pulsed electric current sintering (PECS). The successful development of this (beta+gamma)-TiNbTa material was possible by the optimisation of the milling time (60h) for the MA synthesis and the load and sintering temperature for the PECS (30MPa and 1500°C), as key parameters. Furthermore, the selected heating and cooling rates were 500°Cmin−1 and free cooling, respectively, to help maintain the lowest particle size and to avoid the formation of a detrimental high stiffness, hexagonal (alpha)-Ti alloy. All these optimised experimental conditions enabled the production of a full densified (beta+gamma)-TiNbTa material, with partially nanostructured areas and two TiNbTa alloys, with a body centred cubic (beta) and a novel face-centred cubic (gamma) structures. The interesting microstructural characteristics gives the material high hardness and mechanical strength that, together with the known low elastic modulus for the beta-Ti alloys, makes them suitable for their use as potential biomaterials for bone replacement implants.
Aberrations introduced by the atmospheric turbulence in large telescopes are compensated using adaptive optics systems, where the use of deformable mirrors and multiple sensors relies on complex ...control systems. Recently, the development of larger scales of telescopes as the E-ELT or TMT has created a computational challenge due to the increasing complexity of the new adaptive optics systems. The Complex Atmospheric Reconstructor based on Machine Learning (CARMEN) is an algorithm based on artificial neural networks, designed to compensate the atmospheric turbulence. During recent years, the use of GPUs has been proved to be a great solution to speed up the learning process of neural networks, and different frameworks have been created to ease their development. The implementation of CARMEN in different Multi-GPU frameworks is presented in this paper, along with its development in a language originally developed for GPU, like CUDA. This implementation offers the best response for all the presented cases, although its advantage of using more than one GPU occurs only in large networks.
Introduction The end of the coronavirus disease 2019 (COVID-19) pandemic has been declared by the World Health Organization on May 5, 2023. Several vaccines were developed, and new data is being ...published about their effectiveness. However, the clinical trials for the vaccines were performed before the Omicron variant appeared and there are population groups where vaccine effectiveness still needs to be tested. The overarching goal of the present study was to analyze the effects of COVID-19 vaccination before and after the Omicron variant in patients considering comorbidities in a population from Nuevo Leon, Mexico. Methods Epidemiological COVID-19 data from the Mexican Social Security Institute were collected from 67 hospitals located in northeastern Mexico, from July 2020 to May 2023, and a total of 669,393 cases were compiled, 255,819 reported a SARS-CoV-2 positive reverse transcription quantitative polymerase chain reaction (RT-qPCR) test or a positive COVID-19 antigen rapid test. Results Before Omicron (BO, 2020-2021), after 14 days of two doses of COVID-19 vaccine, BNT162b2 and ChAdOx1 vaccines were effective against infection in non-comorbid and all comorbid subgroups, whereas after Omicron (AO, 2022- 2023) there was no significant effectiveness against infection with none of the vaccines. Regarding hospitalization BO, BNT162b2, ChAdOx1, CoronaVac and mRNA-1273 significantly protected non-comorbid patients whereas BNT162b2, ChAdOx1, and mRNA-1273, protected all comorbid subgroups against hospitalization. AO, BNT162b2, ChAdOx1, CoronaVac and mRNA-1273 were effective against hospitalization in non-comorbid patients whereas for most comorbid subgroups BNT162b2, ChAdOx1 and CoronaVac were effective against hospitalization. Non-comorbid patients were protected against death as an outcome of COVID-19 during the BO period with most vaccines whereas a reduction in effectiveness was observed AO with mRNA-1273 vaccines in patients with hypertension, and diabetes mellitus. Discussion BO, COVID-19 vaccines were effective against infection, hospitalization, and death whereas AO, COVID-19 vaccines failed to protect the population from COVID-19 infection. A varying effectiveness against hospitalization and death is observed AO.
Antecedentes: El seguimiento de egresados en ciencias de la salud es de relevancia debido al compromiso de las universidades de formar profesionales que contribuyan a resolver los problemas de salud ...del país. La Universidad Nacional Autónoma de México (UNAM) cuenta con egresados en ciencias de la salud que cada año se incorporan al campo laboral. Objetivo: Identificar la percepción de los egresados de ciencias de la salud de 1994 a 2015 respecto su formación académica y su incorporación laboral, y compararla según licenciatura y plantel. Material y métodos: Estudio observacional, transversal, comparativo y cuantitativo. La muestra de 26 866 graduados se obtuvo de la información de tres décadas del cuestionario institucional para egresados de la Dirección General de Planeación de la UNAM. Resultados: La mayoría de los egresados fue del sexo femenino (68.4 %), con ingreso a la licenciatura entre los 19 y 20 años (65.4 %). Al menos 47 % trabajaba; la incorporación laboral dependió de no contar con ingresos, mayor promedio, no haber presentado exámenes extraordinarios ni recursado materias, entre otros. Conclusiones: La inserción laboral adecuada se asocia a iniciar la licenciatura a los 18 años, contar con apoyo económico, tener promedio de 8.1 o más y percibir la formación académica y docente baja.
Selenium is an essential micronutrient but at high concentrations can produce severe cytotoxicity and genomic damage. We have evaluated the cytotoxicity, ultrastructural and mitochondrial alterations ...of the two main selenium inorganic species; selenite and selenate, in the eukaryotic microorganism Tetrahymena thermophila. In this ciliate, selenite is more toxic than selenate. Their LC50 values were calculated as 27.65 μM for Se(IV) and 56.88 mM for Se(VI). Significant levels of peroxides/hydroperoxides are induced under low-moderate selenite or selenate concentrations. Se(VI) exposures induce an immediate mitochondrial membrane depolarization. Selenium treated cells show an intense vacuolization and some of them present numerous discrete and small electrondense particles, probably selenium deposits. Mitochondrial fusion, an intense swelling in peripheral mitochondria and mitophagy are detected in selenium treated cells, especially in those exposed to Se (IV). qRT-PCR analysis of diverse genes, encoding relevant antioxidant enzymes or other proteins, like metallothioneins, involved in an environmental general stress response, have shown that they may be crucial against Se(IV) and/or Se (VI) cytotoxicity.
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•In the ciliate T. thermophila selenite is much more toxic than selenate.•Both selenium species generate abundant peroxides/hydroperoxides.•Mitochondrial membrane depolarization and cellular selenium bioaccumulation are detected. Induction of mitochondrial swelling, mitophagy and macroautophagy are also present.•Genes encoding metallothioneins and diverse antioxidant enzymes respond to selenium stress.
The pathophysiological mechanisms underlying Myocardial Infarction with Non-Obstructive Coronary Artery Disease (MINOCA) are still under debate. Lipoprotein (a) Lp(a) has proinflammatory and ...prothrombotic actions and has been involved in the pathogenesis of atherosclerosis. However, no previous studies have linked Lp(a) levels with the probability of developing MINOCA. Moreover, the relationship between MINOCA and the plasma levels of other proatherogenic and proinflammatory molecules such as Interleukin-18 (IL18) and proprotein convertase subtilisin/kexin type 9 (PCSK9) has not been studied. We conducted a prospective, multicenter study involving 1042 patients with acute myocardial infarction (AMI). Seventy-six patients had no significant coronary lesions. All patients underwent plasma analysis on admission. MINOCA patients were younger (57 (47-68) vs. 61 (52-72) years;
= 0.010), more frequently female (44.7% vs. 21.0%;
< 0.001), and had lower rates of diabetes and of Lp(a) > 60 mg/dL (9.2% vs. 19.8%;
= 0.037) than those with coronary lesions; moreover, High Density Lipoprotein cholesterol (HDL-c) levels were higher in MINOCA patients. The absence of Lp(a) > 60 mg/dL and of diabetes were independent predictors of MINOCA, as well as female sex, high HDL-c levels, and younger age. IL-18 and PCSK9 levels were not predictors of MINOCA. During a follow-up of 5.23 (2.89, 7.37) years, the independent predictors of the primary outcome (acute ischemic events or death) in the whole sample were Lp(a) > 60 mg/dL, older age, low estimated Glomerular Filtration rate (eGFR), hypertension, previous heart failure (HF), coronary artery bypass graft, use of insulin, and no therapy with acetylsalicylic acid. In conclusion, in AMI patients, the absence of high Lp(a) levels, as well high HDL-c levels, were independent predictors of the inexistence of coronary artery disease. High Lp (a) levels were also an independent predictor of ischemic events or death.
ChatGPT es un asistente virtual con inteligencia artificial que utiliza lenguaje natural para comunicarse, es decir, mantiene conversaciones como las que se tendrían con otro humano. Puede aplicarse ...en educación a todos los niveles, que incluye la educación médica, tanto para la formación, la investigación, la escritura de artículos científicos, la atención clínica y la medicina personalizada. Puede modificar la interacción entre médicos y pacientes para mejorar los estándares de calidad de la atención médica y la seguridad, por ejemplo, al sugerir medidas preventivas en un paciente que en ocasiones no son consideradas por el médico por múltiples causas. Los usos potenciales del ChatGPT en la educación médica, como una herramienta de ayuda en la redacción de artículos científicos, un asistente en la atención para pacientes y médicos para una práctica más personalizada, son algunas de las aplicaciones que se analizan en este artículo. Los aspectos éticos, originalidad, contenido inapropiado o incorrecto, citas incorrectas, ciberseguridad, alucinaciones y plagio son ejemplos de las situaciones a tomar en cuenta al usar las herramientas basadas en inteligencia artificial en medicina.
Follicle-stimulating hormone (FSH) stimulates the proliferation, survival, and estradiol synthesis of granulosa cells by binding to their G protein-coupled receptors. Although FSH activates ...sphingosine kinase-1 (SPHK1) to induce sphingosine-1-phosphate (S1P) synthesis, which is required to mediate the proliferative and survival effect of this gonadotrophin, the mechanisms, and the role of S1P in estradiol synthesis have not been reported. This study aimed to evaluate the importance of FSH-induced S1P synthesis as a mediator of the effects of this gonadotrophin on granulosa cell viability and steroidogenesis and to determine if FSH-induced S1P synthesis depends on estradiol, cAMP, PKA, or PKC. To achieve these objectives, we tested the effects of FSH, a sphingosine kinase-1 inhibitor (SKI-178), estradiol and inhibitors of aromatase, cAMP, PKA, and PKC (Formestane, MDL-12330A, H-89 dihydrochloride hydrate and Calphostin C respectively), on granulosa cell viability, S1P and estradiol production, and the mRNA expression of CYP19A1 and STAR in four in vitro culture experiments. The addition of FSH (1 ng/mL) increased (P < 0.05) granulosa cells number and S1P concentration in the culture media. Conversely, the addition of SKI-178 (10 μM) reduced (P < 0.05) S1P concentration negating the effect of FSH on cell viability. Inhibition of PKC and PKA, but not cAMP, reduced (P < 0.05) S1P secretion of FSH treated granulosa cells. It is important to note that the reduction in S1P secretion was strong (49 %) with the use of the PKC inhibitor. The use of formestane (10 μg) did not modify (P > 0.05) S1P secretion in FSH-treated cells; however, the addition of 5 or 10 ng/mL of estradiol increased (P < 0.05) S1P secretion. Finally, FSH increased (P < 0.05) estradiol concentration in the culture media, but this effect was not blocked by the inhibition of S1P synthesis. Similarly, FSH, SKI-178 or their combination did not modify the mRNA expression of CYP19A1 and STAR. In conclusion, S1P synthesis is stimulated FSH in granulosa cells and mediated mainly by PKC. S1P in turn promotes the granulosa cell viability, however, this does not influence estradiol synthesis. Additionally, estradiol synthesis induced by FSH is not essential for S1P synthesis, however high estradiol concentration may stimulate S1P production by granulosa cells.
Clinical data indicate that patients with C-reactive protein (CRP) levels higher than 2 mg per liter suffer from persistent inflammation, which is associated with high risk of cardiovascular disease ...(CVD). We determined whether a panel of biomarkers associated with CVD could predict recurrent events in patients with low or persistent inflammation and coronary artery disease (CAD). We followed 917 patients with CAD (median 4.59 ± 2.39 years), assessing CRP, galectin-3, monocyte chemoattractant protein-1 (MCP-1), N-terminal fragment of brain natriuretic peptide (NT-proBNP) and troponin-I plasma levels. The primary outcome was the combination of cardiovascular events (acute coronary syndrome, stroke or transient ischemic event, heart failure or death). Patients with persistent inflammation (
= 343) showed higher NT-proBNP and MCP-1 plasma levels compared to patients with CRP < 2 mg/L. Neither MCP-1 nor NT-proBNP was associated with primary outcome in patients with CRP < 2 mg/L. However, NT-proBNP and MCP-1 plasma levels were associated with increased risk of the primary outcome in patients with persistent inflammation. When patients were divided by type of event, MCP-1 was associated with an increased risk of acute ischemic events. A significant interaction between MCP-1 and persistent inflammation was found (synergy index: 6.17 (4.39-7.95)). In conclusion, MCP-1 plasma concentration is associated with recurrent cardiovascular events in patients with persistent inflammation.
Information on the correlations from solar Shack–Hartmann wavefront sensors is usually used for reconstruction algorithms. However, modern applications of artificial neural networks as adaptive ...optics reconstruction algorithms allow the use of the full image as an input to the system intended for estimating a correction, avoiding approximations and a loss of information, and obtaining numerical values of those correlations. Although studied for night-time adaptive optics, the solar scenario implies more complexity due to the resolution of the solar images potentially taken. Fully convolutional neural networks were the technique chosen in this research to address this problem. In this work, wavefront phase recovery for adaptive optics correction is addressed, comparing networks that use images from the sensor or images from the correlations as inputs. As a result, this research shows improvements in performance for phase recovery with the image-to-phase approach. For recovering the turbulence of high-altitude layers, up to 93% similarity is reached.
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