Fractal dimension analysis of grey matter in multiple sclerosis

The fractal dimension (FD) is a quantitative parameter that characterizes the morphometric variability of a complex object. Among other applications, FD has been used to identify abnormalities of the human brain in conventional magnetic resonance imaging (MRI), including white matter abnormalities in patients with Multiple Sclerosis (MS). Extensive grey matter (GM) pathology has been recently identified in MS and it appears to be a key factor in long-term disability. The aim of the present work was to assess whether FD measurement of GM in T1 MRI sequences can identify GM abnormalities in patients with MS in the early phase of the disease. A voxel-based morphometry approach optimized for MS was used to obtain the segmented brain, where we later calculated the three-dimensional FD of the GM in MS patients and healthy controls.We found that patients with MS had a significant increase in the FD of the GM compared to controls. Such differences were present even in patients with short disease durations, including patients with first attacks of MS. In addition, the FD of the GM correlated with T1 and T2 lesion load, but not with GM atrophy or disability. The FD abnormalities of the GM here detected differed from the previously published FD of the white matter in MS, suggesting that different pathological processes were taking place in each structure. These results indicate that GM morphology is abnormal in patients with MS and that this alteration appears early in the course of the disease

Long-term analysis of antibodies elicited by SPUTNIK V: A prospective cohort study in Tucumán, Argentina

Background: Gam-COVID-Vac (SPUTNIK V) has been granted emergency use authorization in 70 nations and has been administered to millions worldwide. However, there are very few peer-reviewed studies describing its effects. Independent reports regarding safety and effectiveness could accelerate the final approval by the WHO. We aimed to study the long-term humoral immune response in nay¨ve and previously infected volunteers who received SPUTNIK V. Methods: Humoral immune responses, assayed by anti-SARS-CoV-2-spike-RBD IgG ELISA and neutralization assays, were measured in 602 healthcare workers at 0, 14, 28, 60 and 180 days after receiving SPUTNIK V between December 2020 and July 2021 in Tucuman, Argentina. Findings: Seroconversion was detected in 97% of individuals after 28 days post-vaccination (dpv) (N = 405). Anti-RBD titers began to decrease after 60 dpv (N = 328), but remained detectable in 94% at 90 dpv (N = 224). At 180 dpv, anti-RDB titers persisted in 31% (N = 146). Previous infection triggered an increased immune response to the first dose and increased neutralization activity against variants of concern (VOC). Second doses in previously infected individuals further increased titers, even 90 dpv (N = 75). Basal antibody titers had more influence on postvaccination anti-RBD responses than the time elapsed between diagnosis and vaccination (N = 274). Interpretation: Data presented herein provides essential knowledge regarding the kinetics of antibodies induced by SPUTNIK V up to six months after immunization, and suggests that when considering one-dose vaccination policies for individuals with previous SARS-CoV-2 infection, serological studies to determine basal titers may be important, independent of when diagnosis occurred.Fil: Chahla, Rossana Elena. Ministerio de Salud Pública de Tucumán; ArgentinaFil: Tomas Grau, Rodrigo Hernán. Universidad Nacional de Tucuman. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Gobierno de la Provincia de Tucuman. Ministerio de Salud. Sistema Provincial de Salud. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet Noa Sur. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario.; ArgentinaFil: Cazorla, Silvia Ines. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Ploper, Diego. Universidad Nacional de Tucuman. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Gobierno de la Provincia de Tucuman. Ministerio de Salud. Sistema Provincial de Salud. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet Noa Sur. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario.; ArgentinaFil: Vera Pingitore, Esteban. Universidad Nacional de Tucuman. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Gobierno de la Provincia de Tucuman. Ministerio de Salud. Sistema Provincial de Salud. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet Noa Sur. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario.; ArgentinaFil: Aguilar López, Mónica. Gobierno de la Provincia de Tucuman. Ministerio de Salud. Departamento Bioquimico. Laboratorio de Salud Publica.; ArgentinaFil: Aznar, Patricia. Gobierno de la Provincia de Tucuman. Ministerio de Salud. Departamento Bioquimico. Laboratorio de Salud Publica.; ArgentinaFil: Alcorta, María Elena. Gobierno de la Provincia de Tucuman. Ministerio de Salud. Departamento Bioquimico. Laboratorio de Salud Publica.; ArgentinaFil: Velez, Eva Maria del Mar. Gobierno de la Provincia de Tucuman. Ministerio de Salud. Departamento Bioquimico. Laboratorio de Salud Publica.; ArgentinaFil: Stagnetto, Agustín. Universidad Nacional de Tucuman. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Gobierno de la Provincia de Tucuman. Ministerio de Salud. Sistema Provincial de Salud. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet Noa Sur. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario.; ArgentinaFil: Avila, Cesar Luis. Universidad Nacional de Tucuman. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Gobierno de la Provincia de Tucuman. Ministerio de Salud. Sistema Provincial de Salud. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet Noa Sur. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario.; ArgentinaFil: Maldonado Galdeano, María Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Socias, Sergio Benjamin. Universidad Nacional de Tucuman. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Gobierno de la Provincia de Tucuman. Ministerio de Salud. Sistema Provincial de Salud. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet Noa Sur. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario.; ArgentinaFil: Heinze, Dar. University Of Boston. School Of Medicine. Center For Regenerative Medicine.; Estados UnidosFil: Navarro, Silvia Adriana. Universidad Nacional de Tucuman. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Gobierno de la Provincia de Tucuman. Ministerio de Salud. Sistema Provincial de Salud. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet Noa Sur. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario.; ArgentinaFil: Llapur, Conrado Juan. Ministerio de Salud Pública de Tucumán; ArgentinaFil: Costas, Dardo. Gobierno de la Provincia de Tucuman. Ministerio de Salud. Departamento Bioquimico. Laboratorio de Salud Publica.; ArgentinaFil: Flores, Isolina. Gobierno de la Provincia de Tucuman. Ministerio de Salud. Departamento Bioquimico. Laboratorio de Salud Publica.; ArgentinaFil: Edelstein, Alexis. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; ArgentinaFil: Kowdle, Shreyas. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Perandones, Claudia. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud "Dr. C. G. Malbrán"; ArgentinaFil: Lee, Benhur. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Apfelbaum, Gabriela. Universidad Nacional de Tucumán; ArgentinaFil: Mostoslavsky, Raul. Harvard Medical School; Estados UnidosFil: Mostoslavsky, Gustavo. University Of Boston. School Of Medicine. Center For Regenerative Medicine.; Estados UnidosFil: Perdigon, Gabriela del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Centro de Referencia para Lactobacilos; ArgentinaFil: Chehin, Rosana Nieves. Universidad Nacional de Tucuman. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Gobierno de la Provincia de Tucuman. Ministerio de Salud. Sistema Provincial de Salud. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet Noa Sur. Instituto de Investigaciones En Medicina Molecular y Celular Aplicada del Bicentenario.; Argentin

Evaluation of different total leishmania amazonensis antigens for the development of a first-generation vaccine formulated with a toll-like receptor-3 agonist to prevent cutaneous leishmaniasis

Unfortunately, no any vaccine against leishmaniasis has been developed for human use. Therefore, a vaccine based on total Leishmania antigens could be a good and economic approach; and there are different methodologies to obtain these antigens. However, it is unknown whether the method to obtain the antigens affects the integrity and immune response caused by them. OBJECTIVES: to compare the protein profile and immune response generated by total L. amazonensis antigens (TLA) produced by different methods, as well as to analyse the immune response and protection by a first-generation vaccine formulated with sonicated TLA (sTLA) and polyinosinic:polycytidylic acid [Poly (I:C)]. METHODS: TLA were obtained by four different methodologies and their integrity and immune response were evaluated. Finally, sTLA was formulated with Poly (I:C) and their protective immune response was measured. FINDINGS: sTLA presented a conserved protein profile and induced a strong immune response. In addition, Poly (I:C) improved the immune response generated by sTLA. Finally, sTLA + Poly (I:C) formulation provided partial protection against L. amazonensis infection. MAIN CONCLUSIONS: The protein profile and immune response depend on the methodology used to obtain the antigens. Also, the formulation sTLA + Poly (I:C) provides partial protection against cutaneous leishmaniasis in mice.Fil: Germano, Maria Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Lozano, Esteban Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Sanchez, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Bruna, Flavia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Garcia Bustos, Maria Fernanda. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Patología Experimental. Universidad Nacional de Salta. Facultad de Ciencias de la Salud. Instituto de Patología Experimental; ArgentinaFil: Sosa Lochedino, Arianna Lourdes. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Salomón, María Cristina. Universidad Nacional de Cuyo; ArgentinaFil: Fernandes, Ana Paula. Universidade Federal de Minas Gerais; BrasilFil: Mackern Oberti, Juan Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Cargnelutti, Diego Esteban. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentin

Monitoring ecological change during rapid socio-economic and political transitions: Colombian ecosystems in the post-conflict era

After more than 50-years of armed conflict, Colombia is now transitioning to a more stable social and political climate due to a series of peace agreements between the government and different armed groups. Consequences of these socio-economic and political changes on ecosystems are largely uncertain, but there is growing concern about derived increases in environmental degradation. Here, we review the capacity of Colombia to monitor the state of its ecosystems and their rate of change over time. We found several important programs currently set in place by different institutions as well as by independent groups of scientists that address different aspects of environmental monitoring. However, most of the current initiatives could be improved in terms of data coverage, quality and access, and could be better articulated among each other. We propose a set of activities that would increase the capacity of Colombia to monitor its ecosystems, provide useful information to policy makers, and facilitate scientific research. These include: 1) the establishment of a national center for ecological synthesis that focuses on analyzing existing information; 2) the establishment of an ecological observatory system that collects new information, integrates remote sensing products, and produces near real-time products on key ecological variables; and 3) the creation of new platforms for dialog and action within existing scientific and policy groups

The Changing Landscape for Stroke\ua0Prevention in AF: Findings From the GLORIA-AF Registry Phase 2

Background GLORIA-AF (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation) is a prospective, global registry program describing antithrombotic treatment patterns in patients with newly diagnosed nonvalvular atrial fibrillation at risk of stroke. Phase 2 began when dabigatran, the first non\u2013vitamin K antagonist oral anticoagulant (NOAC), became available. Objectives This study sought to describe phase 2 baseline data and compare these with the pre-NOAC era collected during phase 1. Methods During phase 2, 15,641 consenting patients were enrolled (November 2011 to December 2014); 15,092 were eligible. This pre-specified cross-sectional analysis describes eligible patients\u2019 baseline characteristics. Atrial fibrillation disease characteristics, medical outcomes, and concomitant diseases and medications were collected. Data were analyzed using descriptive statistics. Results Of the total patients, 45.5% were female; median age was 71 (interquartile range: 64, 78) years. Patients were from Europe (47.1%), North America (22.5%), Asia (20.3%), Latin America (6.0%), and the Middle East/Africa (4.0%). Most had high stroke risk (CHA2DS2-VASc [Congestive heart failure, Hypertension, Age  6575 years, Diabetes mellitus, previous Stroke, Vascular disease, Age 65 to 74 years, Sex category] score  652; 86.1%); 13.9% had moderate risk (CHA2DS2-VASc = 1). Overall, 79.9% received oral anticoagulants, of whom 47.6% received NOAC and 32.3% vitamin K antagonists (VKA); 12.1% received antiplatelet agents; 7.8% received no antithrombotic treatment. For comparison, the proportion of phase 1 patients (of N = 1,063 all eligible) prescribed VKA was 32.8%, acetylsalicylic acid 41.7%, and no therapy 20.2%. In Europe in phase 2, treatment with NOAC was more common than VKA (52.3% and 37.8%, respectively); 6.0% of patients received antiplatelet treatment; and 3.8% received no antithrombotic treatment. In North America, 52.1%, 26.2%, and 14.0% of patients received NOAC, VKA, and antiplatelet drugs, respectively; 7.5% received no antithrombotic treatment. NOAC use was less common in Asia (27.7%), where 27.5% of patients received VKA, 25.0% antiplatelet drugs, and 19.8% no antithrombotic treatment. Conclusions The baseline data from GLORIA-AF phase 2 demonstrate that in newly diagnosed nonvalvular atrial fibrillation patients, NOAC have been highly adopted into practice, becoming more frequently prescribed than VKA in Europe and North America. Worldwide, however, a large proportion of patients remain undertreated, particularly in Asia and North America. (Global Registry on Long-Term Oral Antithrombotic Treatment in Patients With Atrial Fibrillation [GLORIA-AF]; NCT01468701

Omecamtiv mecarbil in chronic heart failure with reduced ejection fraction, GALACTIC‐HF: baseline characteristics and comparison with contemporary clinical trials

Aims: The safety and efficacy of the novel selective cardiac myosin activator, omecamtiv mecarbil, in patients with heart failure with reduced ejection fraction (HFrEF) is tested in the Global Approach to Lowering Adverse Cardiac outcomes Through Improving Contractility in Heart Failure (GALACTIC‐HF) trial. Here we describe the baseline characteristics of participants in GALACTIC‐HF and how these compare with other contemporary trials. Methods and Results: Adults with established HFrEF, New York Heart Association functional class (NYHA) ≥ II, EF ≤35%, elevated natriuretic peptides and either current hospitalization for HF or history of hospitalization/ emergency department visit for HF within a year were randomized to either placebo or omecamtiv mecarbil (pharmacokinetic‐guided dosing: 25, 37.5 or 50 mg bid). 8256 patients [male (79%), non‐white (22%), mean age 65 years] were enrolled with a mean EF 27%, ischemic etiology in 54%, NYHA II 53% and III/IV 47%, and median NT‐proBNP 1971 pg/mL. HF therapies at baseline were among the most effectively employed in contemporary HF trials. GALACTIC‐HF randomized patients representative of recent HF registries and trials with substantial numbers of patients also having characteristics understudied in previous trials including more from North America (n = 1386), enrolled as inpatients (n = 2084), systolic blood pressure < 100 mmHg (n = 1127), estimated glomerular filtration rate < 30 mL/min/1.73 m2 (n = 528), and treated with sacubitril‐valsartan at baseline (n = 1594). Conclusions: GALACTIC‐HF enrolled a well‐treated, high‐risk population from both inpatient and outpatient settings, which will provide a definitive evaluation of the efficacy and safety of this novel therapy, as well as informing its potential future implementation

Desarrollo de un sistema de imágenes Raman para detección de fitopatógenos.

Los fitopatógenos son microorganismos capaces de infectar plantas según sus características y entornos. Normalmente los fitopatógenos existen en forma de hongos, bacterias, protozoos, etc. que invaden diferentes partes de una planta como el fruto, hojas, tallos, entre otros, lo cual obligaría a un agricultor a una constante inspección por sintomatología para tomar medidas correctivas y oportunas en un cultivo. En este trabajo se abordó el tema de detección no convencional de dos especies de fitopatógenos fúngicos: \textit{Mycosphaerella fijiensis} y \textit{Colletotrichum gloeosporioides}, cuyo foco de infección son cultivos de alto valor comercial para la agro industria colombiana, principalmente banano y aguacate. Para tal fin, y teniendo en cuenta que un hongo altera la configuración energética de la estructura molecular de una planta, entonces se optó por desarrollar la técnica Raman, e incluso se diseñó y se configuró un equipo de muestreo para tal fin. El equipo construido incluye algunos dispositivos ópticos convencionales como lentes, prismas, espejos, y filtros pero también se complementó con otros sistemas de última tecnología como una cámara CCD PTGrey, y un espectrómetro B\ and W-Tech, obteniendo en definitiva un sistema de muestreo versátil y capaz de trabajar en cualquier ambiente. La detección y el registro de las señales Raman que aquí se obtuvieron corresponden a aquéllas provenientes de moléculas características de la pared celular de estos organismos, tales como quitina y $\beta$ 1,3-glucano, y que se caracterizan por una eficiencia que perfectamente garantiza su utilidad en procesos de control de calidad tanto en las etapas de cosecha como en poscosecha, indicando al usuario la presencia de estos organismos en una fase temprana, a través de imágenes que hacen posible interpretar la información espectral sin necesidad de personal experto, logrando de esta forma brindar un margen de maniobra suficiente para adoptar medidas correctivas al agricultor, haciendo posible evitar la fumigación indiscriminada de los cultivos. Para lograr esto, el equipo fue sometido a un proceso de calibración con diferentes sustancias y en fases diferentes con el propósito de garantizar las condiciones óptimas de operatividad del equipo. Todo esto fue acompañado por otros desarrollos paralelos como configuraciones ópticas auxiliares, interfases electrónicas y de control, diseños mecánicos, sistemas termodinámicos de enfriamiento en el lugar de la muestra, y desarrollo de software. El resultado es un dispositivo capaz de tomar imágenes espectrales, que posteriormente se puede utilizar para entrenar una red neuronal, que en relación a la detección de fitipatógenos en plantas permite garantizar una estimación de más del 90\% de éxito en este proceso.Abstract: Phytopathogens are microorganisms capable of infecting plants according to their characteristics and environments. Normally phytopathogens exist in the form of fungi, bacteria, protozoa, etc. that invade different parts of a plant such as fruit, leaves, stems, among others, which would force a farmer to a constant inspection for symptoms to take corrective and timely measures in a crop. In this work the topic of unconventional detection of two species of fungal phytopathogens was addressed: \textit{Mycosphaerella fijiensis} and \textit{Colletotrichum gloeosporioides}, whose focus of infection are crops of high commercial value for the Colombian agro industry, mainly bananas and avocado. For this purpose, and taking into account that a fungus alters the energy configuration of the molecular structure of a plant, then it was decided to develop the Raman technique; a sampling equipment was designed and configured for this purpose. The built equipment includes some conventional optical devices such as lenses, prisms, mirrors, and filters but it was also complemented with other state-of-the-art systems such as a PTGrey CCD camera, and a B \ and W-Tech spectrometer, ultimately obtaining a versatile sampling system and able to work in any environment. The detection and recording of the Raman signals obtained here correspond to those coming from molecules characteristic of the cell wall of these organisms, such as chitin and $\beta$-1,3-glucan, and which are characterized by an efficiency that perfectly guarantees its usefulness in quality control processes in both the harvest and post-harvest stages, indicating to the user the presence of these organisms at an early stage through images that make it possible to interpret the spectral information without the need for expert personnel, thus achieving a sufficient margin of maneuver to adopt corrective measures, making it possible to avoid the indiscriminate spraying of crops. To achieve this, the equipment was subjected to a calibration process with different substances and in different phases with the purpose of guaranteeing the optimum conditions of operation of the equipment. All this was accompanied by other parallel developments such as auxiliary optical configurations, electronics, control interfaces, mechanical designs, thermodynamic cooling systems at the sample site, and software development. The result is a device capable of taking spectral images, which can later be used to train a neural network, which in relation to the detection of phytopathogens in plants allows to guarantee a 90\% of success in this process.Doctorad

Modelo de ánodo y validación experimental para una celda de combustible microbiana

Resumen: El presente trabajo, aborda el modelamiento matemático y termodinámico de un ánodo para una celda de combustible microbiana empleando la cepa \textit{E.coli} así como su validación experimental mediante el desarrollo de una metodología, esta con el fin de determinar algunos parámetros necesarios para alimentar el modelo (p.ej Electrodo de disco rotatorio) y establecer el grado de validez de la representación matemática del ánodo.\\ Este modelo incluye el abordaje desde dos perspectivas, la primera enmarcada en los fenómenos de transporte, la cual incluye el modelamiento mediante la herramienta computacional FreeFem++, la segunda, consiste en la presentación de este modelo pero empleando la termodinámica de procesos irreversibles, con el fin de mostrar la importancia de los fenómenos cruzados en la descripción matemática de las celdas de combustible microbianas, al final se concluye cual de las dos aproximaciones fue mas importante a la hora de determinar la densidad de corriente en estos dispositivos.Maestrí

Diseño de miembros estructurales de acero formados en frio

148 páginasRESUMEN: Los elementos utilizados en la construcción de estructuras de acero se pueden clasificar en dos grandes grupos: • perfiles laminados en caliente • perfiles formados en frío, obtenidos por procesos de doblado de lámina a temperatura ambiente, utilizando roladoras o prensas. Los perfiles de acero formados en frío, a su vez, se pueden clasificar en dos grupos: • paneles y tableros, que conforman sistemas de cubierta, entrepisos y muros . miembros componentes de estructuras reticulares tipo marco o armadura En el presente trabajo se estudia el comportamiento de los miembros de acero formados en frío que se utilizan en estructuras reticulares, y se desarrolla un software de diseño para este tipo de elementos a la luz de la norma AISI de. 1996. El software desarrollado tiene la capacidad de calcular las propiedades geométricas y torsionales de cualquier sección desarrollada a partir de una sola lámina. Adicionalmente, suministra las resistencias a compresión, flexión, tracción, cortante y arrugamiento del alma de las secciones de mayor aplicación en la construcción. Como ayudas suplementarias, se incluyen la obtención de diagramas de momento y el cálculo de coeficientes de flexión.ABSTRACT: Elements used in steel construction can be grouped in two main families: • hot-rolled shapes • sections coid-formed at room temperature in roll-forming machines or by press brake or bending brake operations Coid formed steel sections, in turn, can be classified into two groups: • paneis and decks used for roofs, floors and walis • individual structural framing members, in rigid frames and trusses This work focuses on the study of the behaviour of coid-formed steel members used in structural frames and in the development of software for design of this type of members according to the AISI 1996 standard. Included software has the capability to calculate geometrical and torsional properties for any section built from a single plate strip. In addition, flexural, compression, tension, shear and crippling strenghts are calculated for the sections most frequently used in construction. As supplementary aids, routines for interna¡ moments diagrams and bending coefficient calculations are included.PregradoIngeniero(a) Civi

Diseño de un manual de estrategias metodológicas para la intervención del riesgo psicosocial basado en los aspectos intrapersonales de la Inteligencia emocional del personal adscrito al MNVCC de la Estación de Policía Cascajal del Distrito Especial de Policía Buenaventura

Diseño de un manual de estrategias metodológicas para la intervención del riesgo psicosocial