9,967 research outputs found
On the nature of some SGRs and AXPs as rotation-powered neutron stars
We investigate the possibility that some SGRs/AXPs could be canonical
rotation-powered pulsars using realistic NS structure parameters instead of
fiducial values. We show that realistic NS parameters lowers the estimated
value of the magnetic field and radiation efficiency, ,
with respect to estimates based on fiducial NS parameters. We show that nine
SGRs/AXPs can be described as canonical pulsars driven by the NS rotational
energy, for computed in the soft (2--10~keV) X-ray band. We compute the
range of NS masses for which . We discuss the observed
hard X-ray emission in three sources of the group of nine potentially
rotation-powered NSs. This additional hard X-ray component dominates over the
soft one leading to in two of them. We show that 9
SGRs/AXPs can be rotation-powered NSs if we analyze their X-ray luminosity in
the soft 2--10~keV band. Interestingly, four of them show radio emission and
six have been associated with supernova remnants (including Swift J1834.9-0846
the first SGR observed with a surrounding wind nebula). These observations give
additional support to our results of a natural explanation of these sources in
terms of ordinary pulsars. Including the hard X-ray emission observed in three
sources of the group of potential rotation-powered NSs, this number of sources
with becomes seven. It remains open to verification
1) the accuracy of the estimated distances and 2) the possible contribution of
the associated supernova remnants to the hard X-ray emission.Comment: 11 pages, 14 figures, to appear in A&
Gene identification for the cblD defect of vitamin B12 metabolism
Background Vitamin B12 (cobalamin) is an essential cofactor in several metabolic pathways. Intracellular conversion of cobalamin to its two coenzymes, adenosylcobalamin in mitochondria and methylcobalamin in the cytoplasm, is necessary for the homeostasis of methylmalonic acid and homocysteine. Nine defects of intracellular cobalamin metabolism have been defined by means of somatic complementation analysis. One of these defects, the cblD defect, can cause isolated methylmalonic aciduria, isolated homocystinuria, or both. Affected persons present with multisystem clinical abnormalities, including developmental, hematologic, neurologic, and metabolic findings. The gene responsible for the cblD defect has not been identified.
Methods We studied seven patients with the cblD defect, and skin fibroblasts from each were investigated in cell culture. Microcell-mediated chromosome transfer and refined genetic mapping were used to localize the responsible gene. This gene was transfected into cblD fibroblasts to test for the rescue of adenosylcobalamin and methylcobalamin synthesis.
Results The cblD gene was localized to human chromosome 2q23.2, and a candidate gene, designated MMADHC (methylmalonic aciduria, cblD type, and homocystinuria), was identified in this region. Transfection of wild-type MMADHC rescued the cellular phenotype, and the functional importance of mutant alleles was shown by means of transfection with mutant constructs. The predicted MMADHC protein has sequence homology with a bacterial ATP-binding cassette transporter and contains a putative cobalamin binding motif and a putative mitochondrial targeting sequence.
Conclusions Mutations in a gene we designated MMADHC are responsible for the cblD defect in vitamin B12 metabolism. Various mutations are associated with each of the three biochemical phenotypes of the disorder
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A prior history of binge-drinking increases sensitivity to the motivational valence of methamphetamine in female C57BL/6J mice.
Methamphetamine (MA) and alcohol use disorders exhibit a high degree of co-morbidity and sequential alcohol-MA mixing increases risk for co-abuse. Recently, we reported greater MA-conditioned reward in male C57BL/6J mice with a prior history of binge alcohol-drinking (14 days of 2-hour access to 5, 10, 20 and 40% alcohol). As female mice tend to binge-drink more alcohol than males and females tend to be more sensitive than males to the psychomotor-activating properties of MA, we first characterized the effects of binge-drinking upon MA-induced place-conditioning (four pairings of 0.25, 0.5, 1, 2, or 4 mg/kg IP) in females and then incorporated our prior data to analyze for sex differences in MA-conditioned reward. Prior binge-drinking history did not significantly affect locomotor hyperactivity or its sensitization in female mice. However, the dose-response function for place-conditioning was shifted to the left of water-drinking controls, indicating an increase in sensitivity to MA-conditioned reward. The examination of sex differences revealed no sex differences in alcohol intake, although females exhibited greater MA-induced locomotor stimulation than males, irrespective of their prior drinking history. No statistically significant sex difference was apparent for the potentiation of MA-conditioned reward produced by prior binge-drinking history. If relevant to humans, these data argue that both males and females with a prior binge-drinking history are similarly vulnerable to MA abuse and it remains to be determined whether or not the neural substrates underpinning this increased vulnerability reflect common or sex-specific adaptations in reward-related brain regions
Cadets’ Perceptions of Gymnastics Instruction for Officer Development
The United States Military Academy has offered gymnastics instruction since 1838. Gymnastics continues to be an integral component of the physical education curriculum. The purpose of this study was to investigate cadets\u27 perceptions of their experiences in a required gymnastics course using the critical incident technique. Students described experiences in the gymnastics class that they believed had a positive or negative influence on their development as cadets and future Army officers. Key elements of their responses were classified into 16 positively perceived and 11 negatively perceived categories. The top positive categories were confidence, encouragement, fear management, modeling, additional instruction, and teamwork. The top negative categories included lack of time, helplessness, discouragement, lack of relevance, unfair grading, and injur
Estudo da aclimatação de lodo ativado com efluente “in natura” da industria de pescado
O presente trabalho estudou a adaptação e a atividade do lodo biológico procedente de um
reator UASB de uma estação de tratamento de efluentes de uma indústria de processamento de pescado,
para remoção biológica de nitrogênio em um Reator Batelada Seqüencial instrumentado em escala de
bancada. A adaptação consistiu em aumento seqüencial da carga aplicada nas razões volumétricas efluente
in natura : efluente sintético de 1:3,33; 1:2,5; 1:2,0; sendo a concentração inicial de inóculo empregada de
20 g SSV/L. Durante este período foram acompanhadas as variações de DQO, nitrato e amônia, onde se
obteve uma remoção de até 80% da carga orgânica do efluente e de até 97% da matéria nitrogenada. O
experimento com diluição de 1:3,33 foi realizado com adição de 0,5 % de sal para avaliar o efeito da
salinidade, o qual também é considerado na análise dos resultados obtidos
Fasceíte Necrotizante Causada por Photobacterium Damselae: o Primeiro Caso Descrito em Portugal
Necrotizing fasciitis is a severe soft tissue infection with a high mortality rate and therefore requires emergent surgical treatment. Several microorganisms can cause this infection, Photobacterium damselae being one of them, with only eight cases previously published in the literature. We report the first ever case of necrotizing fasciitis, caused by this microorganism, in Portugal. In this case report the patient survived after several debridement procedures and reconstruction of the upper limb with acellular dermal matrix and skin graft. A brief review of the Photobacterium damselae soft tissue infection reports as well as the clinical presentation, diagnosis, pathophysiology and treatment of necrotizing fasciitis can also be found in this paper.info:eu-repo/semantics/publishedVersio
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