776 research outputs found

    Perspectives on the Trypanosoma cruzi-host cell receptor interaction

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    Chagas disease is caused by the parasite Trypanosoma cruzi. The critical initial event is the interaction of the trypomastigote form of the parasite with host receptors. This review highlights recent observations concerning these interactions. Some of the key receptors considered are those for thromboxane, bradykinin, and for the nerve growth factor TrKA. Other important receptors such as galectin-3, thrombospondin, and laminin are also discussed. Investigation into the molecular biology and cell biology of host receptors for T. cruzi may provide novel therapeutic targets

    Reconocimiento de suelos del Aljarafe alto (Sevilla - España)

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    36 páginas.-- fotos.-- perfiles de suelos.-- Un mapa (Se incorporará en breve).-- Memoria presentada en el XXXIII Curso Internacional de Edafología y Biología VegetalDirector: Clemente Salas, LuisEl presente trabajo se realizó en el área central del Aljarafe Alto; entre las coordenadas 06° 05' 59" a 06° 10' 45" longitud norte y 37" 09' 40" a 37° 21' 45" longitud oeste, sobre una superficie de 30 km2, a 24 km al suroeste de Sevilla, próximo al término Municipal de Bollullos de la Mitación. Geomorfológicamente se encuentra en una meseta o penillanura. Siendo el objetivo del presente estudio es el reconocimiento y clasificación taxonómica de los suelos, reconociéndose para una escala 1: 20,000 las siguientes unidades taxonómicas a nivel de subgrupo: Rhodoxeralfs Cálcico, Haploxeralfs Cálcico, Haploxeralfs Aquico y Xerochrepts Calciceróllico; así mismo, se han distinguido las unidades cartográficas: Asociación Rhodoxeralfs Cálcico-Haploxeralfs Cálcico en un 40% la de superficie; Asociación Haploxeralfs Cálcico-Rhodoxeralfs Cálcico en un 30%; evidenciando estas dos asociaciones alta sinuosidad en su distribución morfológica y diferenciándose como tales por el predominio de un taxón sobre el otro. y la asociación Xerochrepts Calciceróllico - Haploxera1fs Cálcico en un 10%; así como las Consociaciones Haploxeralfs Acnico en un 15% y la Consociación Xerochrepts Calciceróllico en un 5%.Patrocinado por la UNESCO, el Instituto de Cooperación Iberoamericana (ICI); el Consejo Superior de Investigaciones Científicas (CSIC) y la Universidad de Sevilla - España.Peer reviewe

    Laboratory Kinetic Studies of OH and CO2 Relevant to Upper Atmospheric Radiation Balance

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    The purpose of this project was to quantify the rates of two processes which are crucial to our understanding of radiative energy balance in the upper atmosphere. The first process is radiative emission from vibrationally hot OH radicals following the H + O3 reaction in the upper mesosphere. The importance of this process depends strongly on the OH radiative emission coefficients. Our goal was to measure the OH permanent dipole moment in excited vibrational states and to use these measurements to construct an improved OH dipole moment function and improved radiative emission coefficients. Significant progress was made on these experiments including the construction of a supersonic jet source for vibrationally excited OH radicals. Unfortunately, our efforts to transport the OH radicals into a second lower pressure vacuum chamber were not successful, and we were unable to make improved dipole moment measurements for OH. The second key kinetic process which we attempted to quantify during this project is the rate of relaxation of bend-excited CO2 by oxygen atoms. Since excitation of the bending vibrational mode of CO2 is the major cooling mechanism in the upper mesosphere/lower thermosphere, the cooling rate of this region depends crucially on the rate of energy transfer out of this state. It is believed that the most efficient transfer mechanism is via atomic oxygen but the rate for this process has not been directly measured in the laboratory at appropriate temperatures and even the room temperature rate remains controversial. We attempted to directly measure the relaxation rate Of CO2 (010) by oxygen atoms using the discharge flow technique. This experiment was set up at Aerodyne Research. Again, significant progress was achieved in this experiment. A hot CO2 source was set up, bend excited CO2 was detected and the rate of relaxation of bend excited CO2 by He atoms was measured. Unfortunately, the project ran out of time before the oxygen atom kinetic studies could be implemented

    QuantiMus: A Machine Learning-Based Approach for High Precision Analysis of Skeletal Muscle Morphology.

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    Skeletal muscle injury provokes a regenerative response, characterized by the de novo generation of myofibers that are distinguished by central nucleation and re-expression of developmentally restricted genes. In addition to these characteristics, myofiber cross-sectional area (CSA) is widely used to evaluate muscle hypertrophic and regenerative responses. Here, we introduce QuantiMus, a free software program that uses machine learning algorithms to quantify muscle morphology and molecular features with high precision and quick processing-time. The ability of QuantiMus to define and measure myofibers was compared to manual measurement or other automated software programs. QuantiMus rapidly and accurately defined total myofibers and measured CSA with comparable performance but quantified the CSA of centrally-nucleated fibers (CNFs) with greater precision compared to other software. It additionally quantified the fluorescence intensity of individual myofibers of human and mouse muscle, which was used to assess the distribution of myofiber type, based on the myosin heavy chain isoform that was expressed. Furthermore, analysis of entire quadriceps cross-sections of healthy and mdx mice showed that dystrophic muscle had an increased frequency of Evans blue dye+ injured myofibers. QuantiMus also revealed that the proportion of centrally nucleated, regenerating myofibers that express embryonic myosin heavy chain (eMyHC) or neural cell adhesion molecule (NCAM) were increased in dystrophic mice. Our findings reveal that QuantiMus has several advantages over existing software. The unique self-learning capacity of the machine learning algorithms provides superior accuracy and the ability to rapidly interrogate the complete muscle section. These qualities increase rigor and reproducibility by avoiding methods that rely on the sampling of representative areas of a section. This is of particular importance for the analysis of dystrophic muscle given the "patchy" distribution of muscle pathology. QuantiMus is an open source tool, allowing customization to meet investigator-specific needs and provides novel analytical approaches for quantifying muscle morphology

    Laboratory Studies of Chemical and Photochemical Processes Relevant to Stratospheric Ozone

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    The purpose of this project is to reduce the uncertainty in several key gas-phase kinetic processes which impact our understanding of stratospheric ozone. The main emphasis of this work is on measuring rate coefficients and product channels for reactions of HO(x) and NO(x) species in the temperature range 200 K to 240 K relevant to the lower stratosphere. The results of these studies will improve models of stratospheric ozone chemistry and predictions of perturbations due to human influences. The second year's effort has focussed the design and construction of the proposed high pressure flow reactor on three separate areas: (1) the construction of the high pressure flow reactor; (2) characterization of the turbulent flow profile; and (3) demonstration of the instrument by measuring HO2 + NO2 and HO2 + NO reaction rate coefficients

    Detection of serum anti-B/B' UsnRNP antibodies in patients with connective tissue diseases by immunoblotting

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    Objective: To investigate the reliability of the immunoblot method in the detection of serum immunoreactivity towards the B/B' polypeptides of U small nuclear ribonucleoproteins (UsnRNP) and to assess the significance of these antibodies in connective tissue disease (CTD) patients. Methods: We tested the sera of 348 patients with CTD (101 SLE, 51 systemic sclerosis, 53 primary Sjogren's syndrome, 27 poly/dermatomyositis, 15 rheumatoid arthritis and 101 overlap CTD), of 31 matched healthy subjects and 13 patients with primary Epstein-Barr virus (EBV) infection with high titre IgG anti-EBV antibodies. IgG anti-UsnRNP antibodies were determined by immunoblotting on nuclear extract from Raji cells (an EBV-immortalised human B lymphoid cell line) and Jurkat cells (a human T lymphoid cell line). Anti-dsDNA antibodies were detected by indirect immunofluorescence on Crithidia luciliae and anti-ENA by counterimmunoelectrophoresis. Anti-dsDNA activity and avidity were measured in SLE sera by ELISA with Scatchard analysis. Results were statistically analysed by chi-square and Mann-Whitney tests. Results: A high frequency of anti-B/B' antibodies was found in the sera of CTD patients, confined to SLE (54.4%) and overlap CTD with SLE features (55,2%). Anti-B/B' immune reactivity was closely associated with other anti-UsnRNP specificities, gel precipitating anti-nRNP and anti-P antibodies. Nine out of 15 (60%) anti-B/B' positive/anti-ENA negative lupus sera on Raji blots were confirmed to be positive also on Jurkat blots. The sera from patients with EBV infection provided, on Raji blots, completely different band patterns from those obtained with auto-immune sera. Conclusions. The Sm B/B' proteins are the predominant or, at least, the most frequently targeted antigens of the UsnRNP auto-immune response in SLE and "lupus-like" overlap CTD. Moreover, anti-B/B' is diagnostically specific for CTD with SLE features. Immunoblotting on human B lymphoid cells is a reliable method, in terms of sensitivity and specificity, for the detection of anti-Sm B/B' antibodies

    Quantifying Four Decades of Arid-region Agricultural Development in Arequipa, Peru Using Landsat

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    The Arequipa Nexus Institute for Food, Energy and the Environment (Nexus Institute) is located in Southwestern Peru, generally bounded by the city of Arequipa to the east, the Majes River to the west, the Pacific Ocean to the south, and the Andes mountains to the north. Though agriculture has been practiced in parts of this cool desert region (MAT~15°C, MA

    El tratamiento odontológico, como ayuda de la radioterapia local

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    Este artículo manifiesta la importancia de la actuación profesional del odontólogo en el diagnóstico precoz y tratamiento del cáncer oral. La Radioterapia local o braquiterapia consiste en la aplicación local de agujas de Iridio radioactiva dentro de la masa tumoral permitiendo un control satisfactorio de los mismos. Sin embargo, como todo tratamiento oncológico no está exento de complicaciones. Las complicaciones derivadas de la braquiterapia y la prevención de las mismas por parte del equipo odontológico, se exponen a continuación

    Herramientas moleculares aplicadas al estudio de aguas para el consumo humano, comunidad El Cacao, Nicaragua

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    Se determinó la presencia de contaminantes microbianos en aguas de consumo humano de la comunidad El Cacao, Mosonte, Nueva Segovia. El análisis se realizó tanto por métodos microbiológicos como por ví­a molecular analizando su interrelación con las enfermedades que se observan en la comunidad. Se obtuvo la presencia de coliformes fecales, totales y Escherichia coli desde la captación hasta el tanque de almacenamiento. Los aislados identificados pertenecen a las bacterias del tipo Alcaligenes y Paenalcaligenes, además de Stenotrophomonas y Serratia. Las cuales son bacterias acuáticas y están asociadas a diversas enfermedades. Además se identificó lapresencia de Aspergillus que han sido bien reportados en diversas enfermedades humanas
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