228 research outputs found

    Competing superconducting and magnetic order parameters and field-induced magnetism in electron doped Ba(Fe1x_{1-x}Cox_{x})2_{2}As2_{2}

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    We have studied the magnetic and superconducting properties of Ba(Fe0.95_{0.95}Co0.05_{0.05})2_{2}As2_{2} as a function of temperature and external magnetic field using neutron scattering and muon spin rotation. Below the superconducting transition temperature the magnetic and superconducting order parameters coexist and compete. A magnetic field can significantly enhance the magnetic scattering in the superconducting state, roughly doubling the Bragg intensity at 13.5 T. We perform a microscopic modelling of the data by use of a five-band Hamiltonian relevant to iron pnictides. In the superconducting state, vortices can slow down and freeze spin fluctuations locally. When such regions couple they result in a long-range ordered antiferromagnetic phase producing the enhanced magnetic elastic scattering in agreement with experiments.Comment: 9 pages, 6 figure

    Effect of Platelet-activating Factor on in vitro and in vivo Interleukin-6 Production

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    The aim of the present study was to investigate the possible effect of platelet-activating factor (PAF), by comparison with interleukin-1β and polyriboinositic/polyribocytidylic (poly I–C) acid, on IL-6 production by L 929 mouse fibroblasts. At concentrations above 1 μM PAF, the production of IL-6 by mouse fibroblasts was enhanced in a dose dependent fashion. At 5 μM PAF, the peak increase (60.1 ± 19.4 U/ml) was similar to that induced by 50 μg/ml poly I–C (60.0 ± 35.0 U/ml) and higher than the one evoked by 100 U/ml IL-1β (3.8 ± 1.8 U/ml). The increase of 11-6 activity induced by 5 μM PAF was maximal after a 22 h incubation period with L 929 cells. Lyso-PAF (5 μM) also increased IL-6 activity from fibroblasts to a similar extent compared with 5 μM PAF. In addition, the IL-6 activity induced by 5 μM PAF was still observed when the specific PAF antagonist, BN 52021 (10 μM), was added to the incubation medium of L 929 cells. The result suggests that the production of IL-6 by L 929 cells evoked by PAF in vitro is not receptor mediated. The in vivo effect of PAF on IL-6 production was also investigated in the rat. Two hours after intravenous injection of PAF (2 to 4 μg/kg), a dramatic increase of IL-6 activity in rat serum was observed, this effect being dose dependent. The increase of IL-6 induced by 3 μg/kg PAF was not observed when the animals were treated with the PAF antagonist, BN 52021 (1 to 60 mg/kg0. These results demonstrate that PAF modulates IL-6 production and that the in vivo effect is receptor mediated

    Bronchial responses to substance P after antigen challenge in the guinea-pig: in vivo and in vitro studies

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    The effect of antigen challenge on the airway responses to substance P and on the epithelial neutral endopeptidase (NEP) activity was investigated in aerosol sensitized guinea-pigs. In vivo, bronchial responses to aerosolized substance P were similar to the responses observed in antigen-challenged guinea-pigs and in the control groups. In contrast, when the guinea-pigs were pretreated with the NEP inhibitor, phosphoramidon, a significant increase in the airway responses to substance P was observed after antigen challenge in vivo. However, in vitro, the contractile responses of the tracheal smooth muscle to substance P were similar between groups of guinea-pigs, in respect to the presence or absence of the epithelium and/or phosphoramidon. Histological studies showed an accumulation of eosinophils in the tracheal submucosa after antigen challenge and intact epithelial cells. These results show that in vivo bronchial hyperresponsiveness to substance P after antigen challenge in the guinea-pig is not associated with increased responses of the smooth muscle to exogenous SP in vitro. In addition, the results with phosphoramidon suggest that loss of NEP activity cannot account for the in vivo bronchial hyperresponsiveness to substance P presently observed

    Competing superconducting and magnetic order parameters and field-induced magnetism in electron-doped \mathrm{Ba}{({\mathrm{Fe}}_{1\ensuremath{-}x}{\mathrm{Co}}_{x})}_{2}{\mathrm{As}}_{2}

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    We have studied the magnetic and superconducting properties of Ba(Fe0.95Co0.05)2As2 as a function of temperature and external magnetic field using neutron scattering and muon spin rotation. Below the superconducting transition temperature the magnetic and superconducting order parameters coexist and compete. A magnetic field can significantly enhance the magnetic scattering in the superconducting state, roughly doubling the Bragg intensity at 13.5 T. We perform a microscopic modeling of the data by use of a five-band Hamiltonian relevant to iron pnictides. In the superconducting state, vortices can slow down and freeze spin fluctuations locally. When such regions couple they result in a long-range ordered antiferromagnetic phase producing the enhanced magnetic elastic scattering in agreement with experiments

    Isolation of a novel thermostable dehydrochlorinase (LinA) from a soil metagenome

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    Hexachlorocyclohexane dehydrochlorinase (LinA) mediates first step of aerobic degradation of a chlorinated insecticide γ-hexachlorocyclohexane (γ-HCH). In this study, we describe characterization of a novel variant (LinA-type2) that is distinct from reported LinAs and is substantially more thermostable than archetypal LinA-UT26. LinA-type2 remains active even after 8 h of incubation at 45 °C, when nearly 50% activity of LinA-UT26 is lost after incubation for 60 min at the same temperature. Circular dichroism analysis revealed that secondary structures of LinA-UT26 and LinA-type2 are similar, but their Tm was 45 and 65 °C, respectively. Thermostability of LinA-type2 makes it suitable for bioreactors where allowance for higher temperatures can be of advantage

    Anthropometric Profile Assessed by Bioimpedance and Anthropometry Measures of Male and Female Rugby Players Competing in the Spanish National League

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    Different rugby positions make different demands on players. It therefore follows that optimum body composition may vary according to the position played. Using anthropometry and bioimpedance analysis (BIA) to assess body composition, the present study aimed to compare the effect of sex and position on body composition variables using anthropometry and BIA methods. A total of 100 competitive rugby players (35 women and 65 men) competing in the First Spanish National League were recruited voluntarily and for convenience for this study. In the laboratory, body composition was assessed by anthropometry, following the recommendations established by the International Society for the Advancement of Kinanthropometry (ISAK), and by direct segmental multi-frequency BIA, following the guidelines established by the Spanish Group of Kinanthropometry (GREC) of the Spanish Federation of Sports Medicine (FEMEDE). We found sex-related differences in height, weight, body mass index and body fat (%) by anthropometry and in body lean mass (%) by DSM-BIA, in 4 of the 6 skinfolds assessed (p < 0.05). We also observed position-related differences in all the variables assessed (p < 0.05) except for lean body mass, as measured by both methods of determining body composition, and front thigh skinfold. Body composition and ∑6skinfolds differs according to sex and playing position, backs (16.6 ± 3.8% and 92.3 ± 33.9 mm,) vs. forwards (20.0 ± 6.7 and 115.3 ± 37.6 mm), and the muscle-adipose (meso-endomorphic somatotype) development predominated in both sexes. Thus, forwards of both sexes are taller, heavier and fatter, possibly due to the specific demands of this position. In addition, body composition measurements vary according to the method used (DSM-BIA vs. anthropometry), indicating that anthropometry is probably the best body composition assessment method

    Continuous propofol perfusion in critically ill children

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    Objetivo: Describir la sedación con perfusión continua de propofol en ni˜nos en estado crítico. Dise˜no: Estudio observacional descriptivo retrospectivo. Ámbito: Unidad de cuidados intensivos pediátricos. Pacientes: Pacientes que requirieron sedoanalgesia entre el 1 de octubre de 2009 y el 30 de septiembre de 2010. Intervenciones: Ninguna. Variables recogidas: Demográficas, clínicas, de laboratorio, diagnóstico, tratamiento, complicaciones y evolución de cada paciente. Se analizaron los posibles efectos adversos asociados a la administración de propofol, comparando el grupo de pacientes a los que se les administró con el resto de los ni˜nos críticos. Resultados: Recibieron propofol en perfusión continua 71 de los 222 pacientes recogidos (32%). Los fármacos sedoanalgésicos más utilizados fueron el midazolam, seguido del fentanilo y del propofol. La dosis media de propofol fue de 2,1 mg/kg/h [desviación estándar (DE) 1,3, rango: 0,5-6)] y la duración media de 6,7 días (DE 8,5; rango: 0,5-40). La edad media fue de 45,8 meses (mediana 24; rango intercuartil: 7-65), siendo el 52% varones. Ningún paciente presentó síndrome de infusión por propofol ni otros efectos adversos graves. Los pacientes tratados con propofol presentaron con mayor frecuencia algunas alteraciones analíticas que el resto, pero no se demostró relación causa efecto con la administración del fármaco. No existieron diferencias significativas en los niveles de lactato ni en la incidencia de infecciones entre ambos grupos. Conclusión: el propofol a una dosis de 1 a 4 mg/kg/h puede utilizarse como un fármaco alternativo para la sedación de mantenimiento en los ni˜nos críticamente enfermos. Sin embargo son necesarios más estudios que valoren su eficacia y seguridad.Q3Q3Artículo original410-415Objective: To describe sedation with continuous perfusion of propofol in critically ill children. Design: A retrospective, descriptive observational study was carried out. Setting: A pediatric intensive care unit. Patients: Pediatric patients requiring sedoanalgesia between October 1, 2009 and September 30, 2010. Interventions: None. Data collected: Demographic, clinical and laboratory test variables, diagnosis, treatment, complications and evolution in each patient. In addition, the potential adverse effects associated with propofol administration were analyzed. Results: Midazolam, fentanyl and propofol were the most commonly used sedative and analgesic drugs. Seventy-one out of 222 patients (32%) received propofol in continuous infusion. The average dose was 2.1 mg/kg/h (SD 1.3, range: 0.5 to 6), and the average duration of treatment was of 6.7 days (SD 8.5 range 0.5---40). Fifty-two percent were males, and the mean patient age was 45.8 months (median: 24; interquartile range: 7-65). No patient developed propofol infusion syndrome or other serious drug-related adverse effects. Patients treated with propofol showed more abnormal laboratory test findings, although no relationship to drug administration could be demonstrated. There were no significant differences in lactate level or in the incidence of infection in either group. Conclusions: Propofol at a dose of 1 to 4 mg/kg/h is a safe alternative for sustained sedation in critically ill children. However, further studies are needed to assess its effects and safety profile

    PolymiRTS Database 2.0: linking polymorphisms in microRNA target sites with human diseases and complex traits

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    The polymorphism in microRNA target site (PolymiRTS) database aims to identify single-nucleotide polymorphisms (SNPs) that affect miRNA targeting in human and mouse. These polymorphisms can disrupt the regulation of gene expression by miRNAs and are candidate genetic variants responsible for transcriptional and phenotypic variation. The database is therefore organized to provide links between SNPs in miRNA target sites, cis-acting expression quantitative trait loci (eQTLs), and the results of genome-wide association studies (GWAS) of human diseases. Here, we describe new features that have been integrated in the PolymiRTS database, including: (i) polymiRTSs in genes associated with human diseases and traits in GWAS, (ii) polymorphisms in target sites that have been supported by a variety of experimental methods and (iii) polymorphisms in miRNA seed regions. A large number of newly identified microRNAs and SNPs, recently published mouse phenotypes, and human and mouse eQTLs have also been integrated into the database. The PolymiRTS database is available at http://compbio.uthsc.edu/miRSNP/

    MicroRNAs in cardiac arrhythmia: DNA sequence variation of MiR-1 and MiR-133A in long QT syndrome.

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    Long QT syndrome (LQTS) is a genetic cardiac condition associated with prolonged ventricular repolarization, primarily a result of perturbations in cardiac ion channels, which predisposes individuals to life-threatening arrhythmias. Using DNA screening and sequencing methods, over 700 different LQTS-causing mutations have been identified in 13 genes worldwide. Despite this, the genetic cause of 30-50% of LQTS is presently unknown. MicroRNAs (miRNAs) are small (∼ 22 nucleotides) noncoding RNAs which post-transcriptionally regulate gene expression by binding complementary sequences within messenger RNAs (mRNAs). The human genome encodes over 1800 miRNAs, which target about 60% of human genes. Consequently, miRNAs are likely to regulate many complex processes in the body, indeed aberrant expression of various miRNA species has been implicated in numerous disease states, including cardiovascular diseases. MiR-1 and MiR-133A are the most abundant miRNAs in the heart and have both been reported to regulate cardiac ion channels. We hypothesized that, as a consequence of their role in regulating cardiac ion channels, genetic variation in the genes which encode MiR-1 and MiR-133A might explain some cases of LQTS. Four miRNA genes (miR-1-1, miR-1-2, miR-133a-1 and miR-133a-2), which encode MiR-1 and MiR-133A, were sequenced in 125 LQTS probands. No genetic variants were identified in miR-1-1 or miR-133a-1; but in miR-1-2 we identified a single substitution (n.100A> G) and in miR-133a-2 we identified two substitutions (n.-19G> A and n.98C> T). None of the variants affect the mature miRNA products. Our findings indicate that sequence variants of miR-1-1, miR-1-2, miR-133a-1 and miR-133a-2 are not a cause of LQTS in this cohort
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