201 research outputs found

    Proteomic analysis of glycosomes from Trypanosoma cruzi epimastigotes

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    In Trypanosoma cruzi, the causal agent of Chagas disease, the first seven steps of glycolysis are compartmentalized in glycosomes, which are authentic but specialized peroxisomes. Besides glycolysis, activity of enzymes of other metabolic processes have been reported to be present in glycosomes, such as β-oxidation of fatty acids, purine salvage, pentose-phosphate pathway, gluconeogenesis and biosynthesis of ether-lipids, isoprenoids, sterols and pyrimidines. In this study, we have purified glycosomes from T. cruzi epimastigotes, collected the soluble and membrane fractions of these organelles, and separated peripheral and integral membrane proteins by Na2CO3 treatment and osmotic shock. Proteomic analysis was performed on each of these fractions, allowing us to confirm the presence of enzymes involved in various metabolic pathways as well as identify new components of this parasite’s glycosomes

    Correlates of condom use in a sample of MSM in Ecuador

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    BACKGROUND: In Ecuador, the prevalence of HIV in the general population is approximately 0.3%. However, up to 17% prevalence has been reported among specific groups of homosexual and bisexual men. The objective of this study is to explore correlates of condom use among men who have sex with men (MSM) across eight cities in Ecuador. METHODS: A cross-sectional survey design was used. A questionnaire including variables on sexual behaviour, demographics, and socio-economic characteristics was distributed to a sample of MSM in eight Ecuadorian cities. RESULTS: Information was obtained for 2,594 MSM across the eight cities. The largest subcategory of self-identification was active bisexuals (35%), followed by those who described themselves as "hombrados" (masculine gays, 22%). The mean age was 25 years, and the majority were unmarried (78%), with a median of 10 years of schooling (IQR 7 – 12). Regarding condom use, 55% of those interviewed had unprotected penetrative sex with each of their last three partners, and almost 25% had never used a condom. The most important correlates of condom use were single status, high life-skills rating, and high socio-economic status (RP 5.45, 95% CI 4.26 – 6.37; RP 1.84, 95% CI 1.79 – 1.86, and RP 1.20, 95% CI 1.01 – 1.31, respectively). CONCLUSION: Our data illustrate the urgent need for targeted HIV-prevention programs for MSM populations in Ecuador. MSM have the highest HIV prevalence in the country, and condom use is extremely low. It is imperative that prevention strategies be re-evaluated and re-prioritized to more effectively respond to the Ecuadorian epidemic

    Synthesis and in vitro antiprotozoal activity of some 2- amino-4-phenyloxazole derivatives

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    Purpose: To prepare some 2-amino-4-(p-substituted phenyl)-oxazole derivatives and to evaluate their in vitro antiprotozoal activity against Giardia lamblia and Trichomonas vaginalis.Methods: The 2-amino-4-(p-substituted phenyl)-oxazoles (a-g) were synthesized by microwave (MW) irradiation of mixtures of p-substituted 2-bromoacetophenones and urea in dimethylformamide (DMF). All compounds were identified by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy and lowand high-resolution mass spectrometry (HRMS). NMR assignments were made based on heteronuclear single quantum coherence (HSQC) and heteronuclear multiple bond correlation (HMBC) experiments. Each synthesized compound’s melting point was determined. Antiprotozoal activity against Giardia intestinalis and Trichomonas vaginalis was quantified using a rigorous and sensitive subculture method. The commercial drug, metronidazole, was used as positive control. The 50 % inhibitory concentration (IC50) of the antiprotozoal agents for each protozoa was determined.Results: Seven 2-amino-4-(p-substituted phenyl)-oxazoles (a-g) were synthesized. The most active compounds against G. lamblia was 2-amino-4-(p-benzoyloxyphenyl)-oxazole (3d) with an IC50 of 1.17 μM, while compound 3e (2-amino-4-(p-bromophenyl)-oxazole) showed the highest anti-trichomonal activity (IC50, 1.89 μM).Conclusion: The in vitro antigiardial activity of 2-amino-4-(p-benzoyloxyphenyl) oxazole was higher than that exhibited by metronidazole; however, it is necessary increase the number of synthetic derivatives in order to be able to determine their structure-activity relationship.Keywords: Antiprotozoal, 2-Amino-4-phenyl-oxazoles, Giardia lamblia, Trichomonas vaginali

    Predictive Control Applied to Matrix Converters: A Systematic Literature Review

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    Power electronic devices play an important role in energy conversion. Among the options, matrix converters, in combination with predictive control, represent a good alternative for the power conversion stage. Although several reviews have been undertaken on this topic, they have been conducted in a non-systematic manner, without indicating how the studies considered were chosen. This paper presents results from a systematic literature review on predictive control applied to matrix converters that included 142 primary papers, which were selected after applying a defined protocol with clear inclusion and exclusion criteria. The study provides a detailed classification of predictive control methods and strategies applied to different matrix converter topologies. Research findings require to be understood in combination to develop a common understanding of the topic and ensure that future research effort is based on solid premises. In light of this, this study identifies and characterizes different predictive control techniques and matrix converter topologies through systematic literature review. The results of the review indicate that interest in the area is increasing. A number of open questions in the field are discussed

    Herramienta de evaluación de gestión para la toma de decisiones en la Fundación V&C basada en la NTC ISO 9001:2015

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    The objective of this research is to design assessment tool for decision-making management in the Fundación Valor y Compromiso (V&C), with the support of process leaders who provided information through the application of a survey, this technique allowed to obtain a diagnosis of the company regarding the use of the current tool. Subsequently, the selection of the most significant management indicators in each process and the design of their respective technical sheet were carried out. Then, the results obtained for the year 2019 were consolidated into a comprehensive evaluation instrument. In the next stage, a pilot test was implemented for the process leaders, which are responsible for monitoring and controlling the management indicators, measuring the performance of each indicator through the qualification obtained concerning a projected goal. In this way, the assessment tool contributes to the continuous improvement of the organization, and connotes itself as an instrument for planning and reviewing activities. Likewise, this tool facilitates decision-making on preventive and corrective actions in processes that have low or high performance, improving the most critical processes such as commercial management and social management, and maintaining the best-performing processes such as legal, contracting and purchases, according to the results obtained in the pilot test carried out.El objetivo de la presente investigación es el diseño de una herramienta de evaluación de gestión para la toma de decisiones en la Fundación Valor y Compromiso (V&C), con el apoyo de los líderes de proceso que aportaron información mediante la aplicacion de una encuesta, esta técnica permitió obtener un diagnóstico de la empresa en cuanto al uso de la herramienta actual. Seguidamente, se llevo a cabo la selección de los indicadores de gestión más significativos en cada proceso y el diseño de su respectiva ficha técnica. Luego, se consolidaron los resultados obtenidos del año 2019 en un instrumento de evaluación integral. En la siguiente etapa, se implementó una prueba piloto a los líderes de proceso, responsables del seguimiento y control de los indicadores de gestión, midiendo el desempeño de cada indicador a través de la calificación obtenida con relación a una meta proyectada. De esta forma, la herramienta de evaluación de gestión aporta al mejoramiento continuo de la organización, y se connota como un instrumento para la planeación y revisión de actividades. Asimismo, esta herramienta facilita la toma de decisión sobre las acciones preventivas y correctivas en los procesos que presentan un bajo o alto desempeño, mejorando los procesos más críticos como gestión comercial y gestión social, y manteniendo los procesos con mejor desempeño como jurídica y contratación y compras, según los resultados obtenidos en la prueba piloto realizada

    The Châtelperronian Neanderthals of Cova Foradada (Calafell, Spain) used imperial eagle phalanges for symbolic purposes

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    Evidence for the symbolic behavior of Neanderthals in the use of personal ornaments is relatively scarce. Among the few ornaments documented, eagle talons, which were presumably used as pendants, are the most frequently recorded. This phenomenon appears concentrated in a specific area of southern Europe during a span of 80 thousand years. Here, we present the analysis of one eagle pedal phalange recovered from the Châtelperronian layer of Foradada Cave (Spain). Our research broadens the known geographical and temporal range of this symbolic behavior, providing the first documentation of its use among the Iberian populations, as well as of its oldest use in the peninsula. The recurrent appearance of large raptor talons throughout the Middle Paleolithic time frame, including their presence among the last Neanderthal populations, raises the question of the survival of some cultural elements of the Middle Paleolithic into the transitional Middle to Upper Paleolithic assemblages and beyond

    Crustal Imbrication in an Alpine Intraplate Mountain Range: A Wide-Angle Cross-Section Across the Spanish-Portuguese Central System

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    Intraplate ranges are topographic features that can occur far from plate boundaries, the expected position of orogens as described in the plate tectonics theory. To understand the lithospheric structure of intraplate ranges, we focused on the Spanish-Portuguese Central System (SPCS), the most outstanding topographic feature in the central Iberian Peninsula. The SPCS is an Alpine range that exhumes Precambrian-Paleozoic rocks and is located at >200 km from the northern border of the Iberian microplate. Here, we provide a P-wave velocity model based on wide-angle seismic reflection/refraction data of the central SPCS (Gredos sector). Our results show: (a) a layered lithosphere characterized by three major interfaces: Conrad, Mohorovicic, and Hales discontinuities, (b) an asymmetry of the crust-mantle boundary under the SPCS, (c) the extent of the Variscan batholith forming the main outcrops of Gredos, and (d) the thinning of the lower crust toward the south. This model suggests that the exhumation of the SPCS basement was driven by a south-vergent thick-skinned thrust system, developed in the southern part of the SPCS and that promoted crustal imbrication and a Mohorovicic discontinuity's offset under the SPCS. Thus, the deformation mechanisms of the crust seem to be controlled by the presence of the late- to post-Variscan granitoids that assimilated the Variscan mid-crustal detachment creating a new rheological boundary. This tectonic structure allowed the formation of Alpine crustal-scale thrust systems that eased coupled deformation of the upper and lower crust, leading to limited underthrusting of both crustal layers.This study has been funded by the Ministry of Science, Innovation and Competitiveness through the Project CIMDEF (CGL2014-56548-P). IP is funded by the Spanish Government and the University of Salamanca (Beatriz Galindo grant BEGAL 18/00090). JA is funded by grant IJC2018-036074-I, funded by MCIN/AEI/10.13039/501100011033. DMP and FGL are also funded by grants CGL2015-71692 (MINECO/ FEDER) and PID2020-118822GB-I00 (MCIN/AEI/10.13039/501100011033).Peer reviewe
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