275 research outputs found

    Thermal convection in fluidized granular systems

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    Thermal convection is observed in molecular dynamic simulation of a fluidized granular system of nearly elastic hard disks moving under gravity, inside a rectangular box. Boundaries introduce no shearing or time dependence, but the energy injection comes from a slip (shear-free) thermalizing base. The top wall is perfectly elastic and lateral boundaries are either elastic or periodic. The observed convection comes from the effect of gravity and the spontaneous granular temperature gradient that the system dynamically develops.Comment: 4 pages, 5 figure

    Tuberculosis y vitamina D: una relación intrigante

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    La tuberculosis permanece como la enfermedad infecciosa que más muertes ha causado a lo largo de la historia de la existencia humana, sin poderse aún lograr su control. En años recientes ha emergido un cúmulo importante de evidencia clínica acerca de la función de la vitamina D (calcitriol o 1,25 hidroxivitamina D) en un papel que va más allá de la homeostasis del calcio. Su papel en el sistema inmunológico es muy interesante vinculando su déficit como un factor de riesgo contribuyente y así mismo fisiopatológico en un gran número de enfermedades autoinmunes e infecciosas. Dentro de éstas se destaca la tuberculosis, enfermedad endémica en nuestro país y en la cual el déficit de dicho compuesto (vitamina D) crea un factor de riesgo para desarrollar esta enfermedad en su forma activa. Presentamos una revisión detallada de los estudios que explican el papel de la vitamina D en la susceptibilidad para el desarrollo de tuberculosis y los resultados de los estudios clínicos de suplencia de la misma publicados a la fecha

    In vivo trypanosomicidal activity of imidazole- or pyrazole-based benzo[ g ]phthalazine derivatives against acute and chronic phases of chagas disease

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    The in vivo trypanosomicidal activity of the imidazole-based benzo[g]phthalazine derivatives 1−4 and of the new related pyrazole-based compounds 5 and 6 has been studied in both the acute and chronic phases of Chagas disease. As a rule, compounds 1−6 were more active and less toxic than benznidazole in the two stages of the disease, and the monosubstituted derivatives 2, 4, and 6 were more effective than their disubstituted analogs. Feasible mechanisms of action of compounds 1−6 against the parasite have been explored by considering their inhibitory effect on the Fe-SOD enzyme, the nature of the excreted metabolites and the ultrastructural alterations produced. A complementary histopathological analysis has confirmed that the monosubstituted derivatives are less toxic than the reference drug, with the behavior of the imidazole-based compound 4 being especially noteworthy.The authors thank the Santander-Universidad Complutense Research Program (Grant GR58/08-921371-891), the Spanish MEC Project (Grant CGL2008-03687-E/BOS), and the MCINN Projects (CTQ2009-14288-C04-01 and Consolider CSD2010-00065) for financial support

    La Leishmaniosis en la provincia de Granada: estudio de la enzootia canina

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    Con el fin de determinar el papel que desempeña el perro en la epidemiología de la Leishmaniosis en la provincia de Granada hemos realizado un estudio de la sintomatología, índice de parasitación y distribución de esta enfermedad en dicho animal. En cuanto a la sintomatología, algunos perros presentaban el cuadro clínico característico de la enfermedad, pero otros, sin embargo, presentaban unos síntomas totalmente inespecíficos y, en consecuencia, fácil de confundir con otras enfermedades. La realización de una encuesta al azar en 1.503 perros proporciona un índice de parasitación del 8,84%, lo que nos da una idea de la importancia de la enfermedad. Además, se puede observar que, aunque los mayores índices de parasitación se encuentran en las comarcas tradicionalmente consideradas endémicas (La Costa y Las Alpujarras), la enfermedad está ampliamente esparcida por toda la provincia y con unos índices dignos de tener en cuenta. En consecuencia, habría que considerar como zona endémica de leishmaniosis a toda la provincia, y no se debería restringir este término solamente a la región costero-alpujarreña, tal y como ha venido sucediendo

    La Leishmaniosis en la provincia de Granada: estudio de la enzootia canina

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    Con el fin de determinar el papel que desempeña el perro en la epidemiología de la Leishmaniosis en la provincia de Granada hemos realizado un estudio de la sintomatología, índice de parasitación y distribución de esta enfermedad en dicho animal. En cuanto a la sintomatología, algunos perros presentaban el cuadro clínico característico de la enfermedad, pero otros, sin embargo, presentaban unos síntomas totalmente inespecíficos y, en consecuencia, fácil de confundir con otras enfermedades. La realización de una encuesta al azar en 1.503 perros proporciona un índice de parasitación del 8,84%, lo que nos da una idea de la importancia de la enfermedad. Además, se puede observar que, aunque los mayores índices de parasitación se encuentran en las comarcas tradicionalmente consideradas endémicas (La Costa y Las Alpujarras), la enfermedad está ampliamente esparcida por toda la provincia y con unos índices dignos de tener en cuenta. En consecuencia, habría que considerar como zona endémica de leishmaniosis a toda la provincia, y no se debería restringir este término solamente a la región costero-alpujarreña, tal y como ha venido sucediendo

    IFNγ Response to Mycobacterium tuberculosis, Risk of Infection and Disease in Household Contacts of Tuberculosis Patients in Colombia

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    OBJECTIVES: Household contacts (HHCs) of pulmonary tuberculosis patients are at high risk of Mycobacterium tuberculosis infection and early disease development. Identification of individuals at risk of tuberculosis disease is a desirable goal for tuberculosis control. Interferon-gamma release assays (IGRAs) using specific M. tuberculosis antigens provide an alternative to tuberculin skin testing (TST) for infection detection. Additionally, the levels of IFNgamma produced in response to these antigens may have prognostic value. We estimated the prevalence of M. tuberculosis infection by IGRA and TST in HHCs and their source population (SP), and assessed whether IFNgamma levels in HHCs correlate with tuberculosis development. METHODS: A cohort of 2060 HHCs was followed for 2-3 years after exposure to a tuberculosis case. Besides TST, IFNgamma responses to mycobacterial antigens: CFP, CFP-10, HspX and Ag85A were assessed in 7-days whole blood cultures and compared to 766 individuals from the SP in Medellín, Colombia. Isoniazid prophylaxis was not offered to child contacts because Colombian tuberculosis regulations consider it only in children under 5 years, TST positive without BCG vaccination. RESULTS: Using TST 65.9% of HHCs and 42.7% subjects from the SP were positive (OR 2.60, p<0.0001). IFNgamma response to CFP-10, a biomarker of M. tuberculosis infection, tested positive in 66.3% HHCs and 24.3% from the SP (OR = 6.07, p<0.0001). Tuberculosis incidence rate was 7.0/1000 person years. Children <5 years accounted for 21.6% of incident cases. No significant difference was found between positive and negative IFNgamma responders to CFP-10 (HR 1.82 95% CI 0.79-4.20 p = 0.16). However, a significant trend for tuberculosis development amongst high HHC IFNgamma producers was observed (trend Log rank p = 0.007). DISCUSSION: CFP-10-induced IFNgamma production is useful to establish tuberculosis infection prevalence amongst HHC and identify those at highest risk of disease. The high tuberculosis incidence amongst children supports administration of chemoprophylaxis to child contacts regardless of BCG vaccination

    5-Hydroxymethylfurfural (HMF) formation during subcritical water extraction

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    The aim of this study was to investigate the effect of material type (artichoke leave, lemon peel, flaxseed meal), extraction temperature (50, 100, 120, 140, 160, 180, 200 C) and static extraction time (5, 15, 30, 45 min) on 5-hydroxymethylfurfural (5-HMF) formation during subcritical water extraction. 5-HMF content of artichoke leave and lemon peel extracts increased 7.2 and 26.1 times with the rise of extraction temperature from 160 to 180 C for 5 min during subcritical water extraction, respectively. Besides, 5-HMF content of artichoke leave, lemon peel and flaxseed meal extracts increased 1.4, 2.0 and 4.5 times as static extraction time increased from 15 to 45 min at 180 C during subcritical water extraction, respectively. The highest 5-HMF content of artichoke leave and lemon peel extracts were obtained as 58.83 and 231.21 mg/L at 180 C and 45 min, respectively. However, for flaxseed meal, the highest 5-HMF content (222.94 mg/L) was obtained at 200 C and 15 min during subcritical water extraction.Project Nos. 2014.M80.02.03, 2014.M80.02.04 by Artvin Coruh University Scientific Research Project Uni

    ATP5H/KCTD2 locus is associated with Alzheimer's disease risk

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    To identify loci associated with Alzheimer disease, we conducted a three-stage analysis using existing genome-wide association studies (GWAS) and genotyping in a new sample. In Stage I, all suggestive single-nucleotide polymorphisms (at P<0.001) in a previously reported GWAS of seven independent studies (8082 Alzheimer's disease (AD) cases; 12 040 controls) were selected, and in Stage II these were examined in an in silico analysis within the Cohorts for Heart and Aging Research in Genomic Epidemiology consortium GWAS (1367 cases and 12904 controls). Six novel signals reaching P<5 × 10-6 were genotyped in an independent Stage III sample (the Fundació ACE data set) of 2200 sporadic AD patients and 2301 controls. We identified a novel association with AD in the adenosine triphosphate (ATP) synthase, H+ transporting, mitochondrial F0 (ATP5H)/Potassium channel tetramerization domain-containing protein 2 (KCTD2) locus, which reached genome-wide significance in the combined discovery and genotyping sample (rs11870474, odds ratio (OR)=1.58, P=2.6 × 10 -7 in discovery and OR=1.43, P=0.004 in Fundació ACE data set; combined OR=1.53, P=4.7 × 10 -9). This ATP5H/KCTD2 locus has an important function in mitochondrial energy production and neuronal hyperpolarization during cellular stress conditions, such as hypoxia or glucose deprivation

    Charge separation relative to the reaction plane in Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}}= 2.76 TeV

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    Measurements of charge dependent azimuthal correlations with the ALICE detector at the LHC are reported for Pb-Pb collisions at sNN=2.76\sqrt{s_{\rm NN}} = 2.76 TeV. Two- and three-particle charge-dependent azimuthal correlations in the pseudo-rapidity range η<0.8|\eta| < 0.8 are presented as a function of the collision centrality, particle separation in pseudo-rapidity, and transverse momentum. A clear signal compatible with a charge-dependent separation relative to the reaction plane is observed, which shows little or no collision energy dependence when compared to measurements at RHIC energies. This provides a new insight for understanding the nature of the charge dependent azimuthal correlations observed at RHIC and LHC energies.Comment: 12 pages, 3 captioned figures, authors from page 2 to 6, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/286
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