281 research outputs found

    Synthesis and Magnetic Characterization of Graphite-Coated Iron Nanoparticles

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    Graphite-coated iron nanoparticles were prepared from magnetite nanoparticles by chemical vapour deposition (CVD) under methane and hydrogen atmosphere. After being purified from carbon excess, graphite-coated iron nanoparticles were tested for morphological and magnetic properties. It was found that, during the thermal process, magnetite nanoparticles 6 nm in size coalesce and transform into graphite-coated iron 200 nm in size, as revealed by scanning electron microscopy (SEM). Raman characterization assessed that high-quality graphite coats the iron core. Magnetic measurements revealed the phase change (magnetite to iron) as an increase in the saturation magnetization from 50 to 165 emu/g after the CVD process

    Trigger efficiencies of a proposed beam monitoring detector (BeBe) for p+p collisions at NICA energies

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    The Multipurpose Detector (MPD) consists of a typical array of sub-detectors to study the nuclear matter originating from the collisions of beams provided by the Nuclotron-based Ion Collider fAcility (NICA). A beam monitoring detector~(BeBe) is proposed for stage 2 of MPD to increase the trigger capabilities. BeBe is constituted of two plastic scintillator disks segmented in 80 cells ± 2 m\pm~2~m away from the interaction point of MPD. Laboratory measurements to obtain the energy resolution of an individual BeBe cell prototype are presented. It is shown that an energy resolution of 22±6%22\pm6\% can be obtained. Based on Monte Carlo simulations, the trigger efficiencies of the BeBe are presented for p+p collisions at 11~GeV considering a threshold in the energy loss of the charged particles reaching the detector

    Improving natural ventilation in hospital waiting and consulting rooms to reduce nosocomial tuberculosis transmission risk in a low resource setting.

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    BACKGROUND: TB transmission in healthcare facilities is an important public health problem, especially in the often-overcrowded settings of HIV treatment scale-up. The problem is compounded by the emergence of drug resistant TB. Natural ventilation is a low-cost environmental control measure for TB infection control where climate permits that is suited to many different areas in healthcare facilities. There are no published data on the effect of simple structural modifications to existing hospital infrastructure to improve natural ventilation and reduce the risk of nosocomial TB transmission. The purpose of this study was to measure the effect of simple architectural modifications to existing hospital waiting and consulting rooms in a low resource setting on (a) improving natural ventilation and (b) reducing modelled TB transmission risk. METHODS: Room ventilation was measured pre- and post-modification using a carbon dioxide tracer-gas technique in four waiting rooms and two consulting rooms in two hospitals in Lima, Peru. Modifications included additional windows for cross-ventilation (n = 2 rooms); removing glass from unopenable windows (n = 2); creation of an open skylight (n = 1); re-building a waiting-room in the open air (n = 1). Changes in TB transmission risk for waiting patients, or healthcare workers in consulting rooms, were estimated using mathematical modelling. RESULTS: As a result of the infrastructure modifications, room ventilation in the four waiting rooms increased from mean 5.5 to 15; 11 to 16; 10 to 17; and 9 to 66 air-changes/hour respectively; and in the two consulting rooms from mean 3.6 to 17; and 2.7 to 12 air-changes/hour respectively. There was a median 72% reduction (inter-quartile range 51-82%) in calculated TB transmission risk for healthcare workers or waiting patients. The modifications cost <US75infourrooms,andUS75 in four rooms, and US1000 and US$7000 in the remaining two rooms. CONCLUSIONS: Simple modifications to existing hospital infrastructure considerably increased natural ventilation, and greatly reduced modelled TB transmission risk at little cost

    Cambios en el perfil bioquímico hepático de alpacas positivas a huevos de Fasciola hepática

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    The aim of this study was to determine changes in the liver biochemical profile in alpacas with presence of F. hepatica eggs. We used serum and feces samples of 35 male alpaca between 2-5 years old, 18 were positives and 17 were negatives in coproparasitologic analysis for F. hepatica eggs. Differences are showed (p&lt;0.05) in the values of ALT, GGT and direct bilirubin between positives y negatives animals. We concluded that there is relationship between presence of F. hepatica eggs and high levels in the liver biochemical profile, maybe due to alterations in the hepatic parenchyma by chronic infection in alpacas.El objetivo del presente estudio fue determinar cambios en el perfil bioquímico hepático en alpacas con presencia de huevos de F. hepatica en heces. Se utilizaron muestras de suero y heces de 35 alpacas machos de entre 2 y 5 años de edad, de los cuales 18 fueron positivos y 17 negativos al examen coproparasitológico (sedimentación) para identificación de huevos de F. hepática. Se observó diferencia significativa (p&lt;0.05) entre los valores de ALT, GGT y bilirrubina directa entre los animales positivos y negativos. Concluimos que la presencia de huevos de Fasciola hepatica guarda relación con la elevación de algunos parámetros del perfil hepática posiblemente por alguna alteración en el parénquima producto de una infección crónica en alpacas

    The role of market concentration in the agrifood industry

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    The role of market concentration and potential market power exertion in the agri-food industry is a topic of longstanding interest and concern to policymakers, stakeholders, and researchers. This study provides a comprehensive overview of recent trends in market concentration upstream, midstream, and downstream the agri-food industry at the global, regional, and country level, and assesses how and to what extent concentration could be affecting market conduct and performance of food systems in developed and developing countries. The analysis additionally discusses, to the extent detectable, implications of concentration, including vertical and horizontal integration that favor concentration, for food security and nutrition and environmental sustainability. While market concentration in the agri-food industry has increased across most segments, the evidence on market power exertion is inconclusive. Several knowledge and data gaps are identified and additional research is necessary to derive more general conclusions and policy recommendations

    The Discovery of the Romero VMS Deposit and Its Bearing on the Metallogenic Evolution of Hispaniola during the Cretaceous

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    The recently discovered Romero deposit, located in the Tres Palmas district, Cordillera Central of the Dominican Republic, has probable reserves of 840,000 oz gold, 980,000 oz silver and 136 Mlb copper. Mineralization is hosted by intermediate volcanic and volcaniclastic rocks of the lower stratigraphic sequence of the Cretaceous Tireo formation. The andesitic host rocks yield a U-Pb zircon concordia age of 116 ± 10 Ma. Au–Ag–Cu(–Zn) mineralization is divided into: (1) an upper domain with stacked massive sulfide lenses and sulfide dissemination within a 20-m-thick level of massive anhydrite-gypsum nodules, and (2) a lower domain with a high-grade stockwork mineralization in the form of cm-scale veins with open space fillings of fibrous silica and chalcopyrite, sphalerite, pyrite (+electrum ± Au–Ag tellurides). The γ34S values of sulfides from the upper (-7.6 and +0.9‰) and lower (-2.4 and +5.6‰) domains are consistent with a heterogeneous sourcing of S, probably combining inorganically and organically induced reduction of Albian-Aptian seawater sulfate. Despite this, a magmatic source for sulfur cannot be discarded. The γ34S (+19.2 and +20.0‰) and _18O (+12.5 and +14.2‰) values of anhydrite-gypsum nodules are also consistent with a seawater sulfate source and suggest crystallization in equilibrium with aqueous sulfides at temperatures higher than 250ºC. These data point to a classification of Romero as a volcanogenic massive sulfide (VMS) deposit formed in an axial position of the Greater Antilles paleo-arc in connection with island arc tholeiitic magmatism during a steady-state subduction regime. Circulation of hydrothermal fluids could have been promoted by a local extensional tectonic regime expressed in the Tres Palmas district as a graben structure.This research has been financially supported by the Spanish projects CGL2012-36263 and CGL2015-65824, the Dominican project 2014-1B4-132, the Catalan projects SGR 2014-1661 and 2007-707 and by Goldquest Mining Corp

    Analyses of chondrogenic induction of adipose mesenchymal stem cells by combined co-stimulation mediated by adenoviral gene transfer

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    INTRODUCTION: Adipose-derived stem cells (ASCs) have the potential to differentiate into cartilage under stimulation with some reported growth and transcriptional factors, which may constitute an alternative for cartilage replacement approaches. In this study, we analyzed the in vitro chondrogenesis of ASCs transduced with adenoviral vectors encoding insulin-like growth factor-1 (IGF-1), transforming growth factor beta-1 (TGF-β1), fibroblast growth factor-2 (FGF-2), and sex-determining region Y-box 9 (SOX9) either alone or in combinations. METHODS: Aggregate cultures of characterized ovine ASCs were transduced with 100 multiplicity of infections of Ad.IGF-1, Ad.TGF-β1, Ad.FGF-2, and Ad.SOX9 alone or in combination. These were harvested at various time points for detection of cartilage-specific genes expression by quantitative real-time PCR or after 14 and 28 days for histologic and biochemical analyses detecting proteoglycans, collagens (II, I and X), and total sulfated glycosaminoglycan and collagen content, respectively. RESULTS: Expression analyses showed that co-expression of IGF-1 and FGF-2 resulted in higher significant expression levels of aggrecan, biglycan, cartilage matrix, proteoglycan, and collagen II (all P ≤0.001 at 28 days). Aggregates co-transduced with Ad.IGF-1/Ad.FGF-2 showed a selective expression of proteoglycans and collagen II, with limited expression of collagens I and × demonstrated by histological analyses, and had significantly greater glycosaminoglycan and collagen production than the positive control (P ≤0.001). Western blot analyses for this combination also demonstrated increased expression of collagen II, while expression of collagens I and × was undetectable and limited, respectively. CONCLUSION: Combined overexpression of IGF-1/FGF-2 within ASCs enhances their chondrogenic differentiation inducing the expression of chondrogenic markers, suggesting that this combination is more beneficial than the other factors tested for the development of cell-based therapies for cartilage repair

    Sarconesin II, a New Antimicrobial Peptide Isolated from Sarconesiopsis magellanica Excretions and Secretions

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    Antibiotic resistance is at dangerous levels and increasing worldwide. The search for new antimicrobial drugs to counteract this problem is a priority for health institutions and organizations, both globally and in individual countries. Sarconesiopsis magellanica blowfly larval excretions and secretions (ES) are an important source for isolating antimicrobial peptides (AMPs). This study aims to identify and characterize a new S. magellanica AMP. RP-HPLC was used to fractionate ES, using C18 columns, and their antimicrobial activity was evaluated. The peptide sequence of the fraction collected at 43.7 min was determined by mass spectrometry (MS). Fluorescence and electronic microscopy were used to evaluate the mechanism of action. Toxicity was tested on HeLa cells and human erythrocytes; physicochemical properties were evaluated. The molecule in the ES was characterized as sarconesin II and it showed activity against Gram-negative (Escherichia coli MG1655, Pseudomonas aeruginosa ATCC 27853, P. aeruginosa PA14) and Gram-positive (Staphylococcus aureus ATCC 29213, Micrococcus luteus A270) bacteria. The lowest minimum inhibitory concentration obtained was 1.9 µM for M. luteus A270; the AMP had no toxicity in any cells tested here and its action in bacterial membrane and DNA was confirmed. Sarconesin II was documented as a conserved domain of the ATP synthase protein belonging to the Fli-1 superfamily. The data reported here indicated that peptides could be alternative therapeutic candidates for use in infections against Gram-negative and Gram-positive bacteria and eventually as a new resource of compounds for combating multidrug-resistant bacteria. © 2019 by the authors

    Estándares Consolidados de Reporte de Evaluaciones Económicas Sanitarias: adaptación al español de la lista de comprobación CHEERS 2022

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    Objectives: Health economic evaluations (HEEs) are comparative analyses of courses of action in terms of both costs and consequences. The Consolidated Health Economic Evaluation Reporting Standards (CHEERS) original version and its adaptation to Spanish were published in 2013. Its objectives were to promote that the HEEs are identifiable, interpretable, and useful for decision making and serve as a reporting guide. The new CHEERS 2022 replaces the previous one and tries to be more easily applied to any HEE and incorporates recent methodological advances and the importance of stakeholder involvement including patients and the general public. Methods: For the present adaptation, the following stages were followed: (1) independent translations of the original list into Spanish, (2) blind back-translations, (3) evaluation of their quality, (4) preparation of a new version in Spanish, (5) review and improvement by the author team, (6) preparation of a new version in Spanish, (7) distribution of the preliminary Spanish version and the original one to the American HTA Network (Red de las Américas de Evaluación de Tecnologías Sanitarias) and Spanish-speaking experts for evaluation and feedback, (8) monitoring of changes to the original list under peer review at British Medical Journal, and (9) consolidation of the final adaptation of the Spanish CHEERS 2022 checklist. Results: In this article, we detail the process and the Spanish adaptation of the 28-item CHEERS 2022 checklist and its recommendations. Conclusions: This list is intended for researchers reporting HEE in peer-reviewed journals and reviewers, editors, and, among others, health technology assessment bodies.Fil: Augustovski, Federico Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto de Efectividad Clínica y Sanitaria; Argentina. Universidad de Buenos Aires. Facultad de Medicina; ArgentinaFil: García Martí, Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto de Efectividad Clínica y Sanitaria; Argentina. Universidad de Buenos Aires; ArgentinaFil: Espinoza, Manuel A.. Pontificia Universidad Católica de Chile; ChileFil: Palacios, Alfredo. Instituto de Efectividad Clínica y Sanitaria; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Económicas; ArgentinaFil: Husereau, Don. Institute Of Health Economics; Canadá. University of Ottawa; CanadáFil: Pichón-riviere, Andres. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Epidemiología y Salud Pública. Instituto de Efectividad Clínica y Sanitaria. Centro de Investigaciones en Epidemiología y Salud Pública; Argentina. Instituto de Efectividad Clínica y Sanitaria; Argentina. Universidad de Buenos Aires. Facultad de Medicina; Argentin
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