Centrolene savagei

Number of Pages: 11Geological SciencesIntegrative Biolog

El problema de Regiomontano

Johann Müller Regiomontano fue un astrónomo y matemático alemán del siglo XV. Su nombre real es Johann Müller y el apodo "Regiomontano" proviene de la traducción latina del nombre de la ciudad alemana donde nació: Königsberg. Resultó un niño prodigio y como tal propuso varios problemas, uno entre tantos, se conoce como el PROBLEMA DE REGIOMONTANO que es un problema de optimización que se resuelve por métodos analíticos, algebraicos y geométricos. La solución geométrica se alcanza ala resolver uno de los casos del famoso problema de Apolonio

Continuum percolation of simple fluids: Energetic connectivity criteria

During the last few years, a number of works in computer simulation have focused on the clustering and percolation properties of simple fluids based in an energetic connectivity criterion proposed long ago by T.L. Hill [J. Chem. Phys. 23, 617 (1955)]. This connectivity criterion appears to be the most appropriate in the study of gas-liquid phase transition. So far, integral equation theories have relayed on a velocity-averaged version of this criterion. We show, by using molecular dynamics simulations, that this average strongly overestimates percolation densities in the Lennard-Jones fluid making unreliable any prediction based on it. Additionally, we use a recently developed integral equation theory [Phys. Rev. E 61, R6067 (2000)] to show how this velocity-average can be overcome.Comment: 14 pages, 2 figure

miMente IA. Herramientas adaptativas para la gestión del aprendizaje

Muchas veces las dificultades en el aprendizaje no se dan por falta de capacidad del estudiante, sino porque su estilo de aprendizaje no concuerda bien con el usado en las clases. Los sistemas informáticos, con una buena base pedagógica, pueden ayudar a disminuir dicha brecha, como lo quiere demostrar una herramienta adaptativa para el aprendizaje virtual desarrollada por investigadores de la Universidad de Medellín y sus aliados de la empresa digital Kuepa

Un universo sonoro en 3D

La tecnología del sonido binaural permite grabar el sonido tal como lo capta el cerebro humano, por ello, al reproducirlo de esta manera se puede apreciar su riqueza y tridimensionalidad. El Grupo de Investigación Estudios en Cultura Audiovisual (ECA) de la Universidad de Medellín diseñó un dispositivo de grabación que facilita este fascinante recurso para proyectos musicales, audiovisuales, empresariales, comunicacionales y artísticos

Obesity by BMI and central obesity in adolescents from Comodoro Rivadavia, Patagonia Argentina

Antecedentes: La prevalencia de obesidad infantil y adolescente resulta relevante ya que con frecuencia el sobrepeso a esa edad persistirá en la vida adulta. Objetivo: Determinar sobrepeso y obesidad en una población adolescente de Comodoro Rivadavia, Patagonia Argentina. Métodos: Se utilizaron las tablas propuestas para el índice de masa corporal (IMC) y la circunferencia de cintura (CC) por los siguientes tres grupos: International Obesity Taskforce (IOTF), Centers for Disease Control and Prevention (CDC) y la Organización Mundial de la Salud (OMS). Se evaluó el grado de concordancia en las definiciones, en relación a las tablas empleadas. Se estudiaron por muestreo no probabilístico y consecutivo, 402 voluntarios (279 mujeres y 123 varones) de edades comprendidas entre 12 y 16 ± 0,5 años. Con consentimiento escrito de los padres y asentimiento de los voluntarios, se midió peso, talla presión arterial y CC. Se calcularon percentiles del IMC y de la CC. Resultados: Al utilizar tanto las tablas IOTF como CDC más del 40 % de la población presentó sobrepeso u obesidad según el IMC. No se evidenciaron diferencias estadísticamente significativas al evaluar sobrepeso según sexo mientras que los varones presentaron mayores índices de obesidad con ambas definiciones (p0,05). Conclusiones: La prevalencia de obesidad es elevada tanto al considerar percentiles tanto de IMC, como de CC. El grado de acuerdo de las definiciones es adecuado. Estos resultados aportan información regional inexistente hasta este momento y alertan sobre una situación que requiere una urgente intervención sanitaria.Background: The prevalence of overweight and obesity in childhood and adolescence is important because it will frequently persist in adult life. Objective: To determine overweight and obesity in a group of adolescents from Comodoro Rivadavia, Argentine Patagonia through the use of body mass index (BMI) and waist circumference. Methods: Obesity Taskforce (IOTF), Centers for Disease Control and Prevention (CDC) and Word Health Organization (WHO) tables were used. The agreement degree in the definitions was evaluated in relation with the tables used. 402 volunteers were studied, aged between 12 to 16 years old ± 0.5. Written parental consent and assent of volunteers were obtained. Anthropometry, blood pressure were measured, andbody mass index and waist circumference´s percentile (Pc) were calculated. Results: Over 40 % of the adolescents were obese or overweight (BMI equal or major 95 or 85, respectively). There weren´t significant statistic difference between overweight and gender while the males showed majors obesity index with both definitions (p0.05). Conclusions: The prevalence of obesity is high with both BMI, as waist circumference percentiles. The degree agreement of the definition is adequate. These results contribute regional information that actually it is non-existent up to now and it alert about a situation that requires an urgent sanitary intervention.Fil: Ponce, Graciela M.. Universidad Nacional de la Patagonia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Quezada, Andrés O.. Universidad Nacional de la Patagonia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Rodríguez, María A. Universidad Nacional de la Patagonia; ArgentinaFil: Boeri, Mónica P.. Universidad Nacional de la Patagonia; ArgentinaFil: Soto, Mariana S.. Universidad Nacional de la Patagonia; ArgentinaFil: Brites, Fernando Daniel. Universidad de Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Production and purification of immunologically active core protein p24 from HIV-1 fused to ricin toxin B subunit in E. coli

<p>Abstract</p> <p>Background</p> <p>Gag protein from HIV-1 is a polyprotein of 55 kDa, which, during viral maturation, is cleaved to release matrix p17, core p24 and nucleocapsid proteins. The p24 antigen contains epitopes that prime helper CD4 T-cells, which have been demonstrated to be protective and it can elicit lymphocyte proliferation. Thus, p24 is likely to be an integral part of any multicomponent HIV vaccine. The availability of an optimal adjuvant and carrier to enhance antiviral responses may accelerate the development of a vaccine candidate against HIV. The aim of this study was to investigate the adjuvant-carrier properties of the B ricin subunit (RTB) when fused to p24.</p> <p>Results</p> <p>A fusion between ricin toxin B subunit and p24 HIV (RTB/p24) was expressed in <it>E. coli</it>. Affinity chromatography was used for purification of p24 alone and RTB/p24 from cytosolic fractions. Biological activity of RTB/p24 was determined by ELISA and affinity chromatography using the artificial receptor glycoprotein asialofetuin. Both assays have demonstrated that RTB/p24 is able to interact with complex sugars, suggesting that the chimeric protein retains lectin activity. Also, RTB/p24 was demonstrated to be immunologically active in mice. Two weeks after intraperitoneal inoculation with RTB/p24 without an adjuvant, a strong anti-p24 immune response was detected. The levels of the antibodies were comparable to those found in mice immunized with p24 alone in the presence of Freund adjuvant. RTB/p24 inoculated intranasally in mice, also elicited significant immune responses to p24, although the response was not as strong as that obtained in mice immunized with p24 in the presence of the mucosal adjuvant cholera toxin.</p> <p>Conclusion</p> <p>In this work, we report the expression in <it>E. coli </it>of HIV-1 p24 fused to the subunit B of ricin toxin. The high levels of antibodies obtained after intranasal and intraperitoneal immunization of mice demonstrate the adjuvant-carrier properties of RTB when conjugated to an HIV structural protein. This is the first report in which a eukaryotic toxin produced in <it>E. coli </it>is employed as an adjuvant to elicit immune responses to p24 HIV core antigen.</p

Metabolic syndrome and Growth Differentiation Factor 15 in older adults

This is a pre-print of an article published in GeroScience. The final authenticated version is available online at: https://doi.org/10.1007/s11357-021-00370-wGrowth Differentiation Factor 15 (GDF-15) is a cytokine produced in response to tissue injury and inflammatory states that may capture distinct pathways between the risk factors aggregated within metabolic syndrome (MS) and the development of diabetes and cardiovascular disease. Objective: To study the association of MS and its components with GDF-15 among older adults, examining the roles of body fat distribution, glucose metabolism, and inflammation. Methods: Data were taken from the Seniors-ENRICA-2 study in Spain, which included 1938 non-institutionalized individuals aged ≥65 years free of diabetes and cardiovascular disease. MS was defined as the presence of ≥3 of the following components: high waist circumference, elevated fasting blood glucose levels, raised blood pressure, increased triglyceride levels; and low serum high-density lipoprotein (HDL) cholesterol. Statistical analyses were performed with linear regression models and adjusted for potential sociodemographic and lifestyle confounders. Results: MS was associated with higher GDF-15 levels (fully adjusted mean increase [95% confidence interval] = 9.34% [5.16,13.7]). The MS components showing the strongest associations were high waist circumference (6.74% [2.97,10.6]), elevated glucose levels (4.91% [0.77,9.23]), and low HDL-cholesterol (8.13% [3.51,13.0]). High waist-to-hip ratio (7.07% [2.63,11.7]), urine albumin (12.1% [2.57,22.5]), and C-reactive protein (10.4% [3.89,17.3]) were also associated with increased GDF-15. Conclusion: MS was associated with higher GDF-15 levels in older adults. Abdominal obesity, hyperglycemia -possibly linked to microvascular disease, as inferred from elevated urine albumin-, low HDL-cholesterol, and inflammation were the main drivers of this associationThis work was supported by the Instituto de Salud Carlos III, State Secretary of R+D+I and FEDER/FSE (FIS grants 18/287, 19/319); grant 2020/017 from the National Plan on Drug Addiction (Ministry of Health), and the MITOFUN project grant from the Fundación Francisco Soria Melguiz