1,538 research outputs found

    The Stripe Fortified GCT:A new GCT design for maximizing the controllable current

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    In this paper we introduce a new GCT design, namely the Stripe Fortified GCT, for the purpose of maximizing the controllable current by optimizing the current flow path in the device during turn-off. The main design of the new device along with variants are introduced. The MCC performance of this novel structure is assessed with a developed two dimensional model for full wafer simulations. Our results show that this new design is a very good candidate for increasing the MCC to values more than 5000A

    Intensity-dependent reductions in resting blood pressure following short-term isometric exercise training

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    To reduce resting blood pressure, a minimum isometric exercise training (IET) intensity has been suggested, but this is not known for short-term IET programmes. We therefore compared the effects of moderate- and low-intensity IET programmes on resting blood pressure. Forty normotensive participants (22.3 ± 3.4 years; 69.5 ± 15.5 kg; 170.2 ± 8.7 cm) were randomly assigned to groups of differing training intensities [20%EMGpeak (~23%MVC, maximum voluntary contraction, or 30%EMGpeak (~34%MVC)] or control group; 3 weeks of IET at 30%EMGpeak resulted in significant reductions in resting mean arterial pressure (e.g. −3.9 ± 1.0 mmHg, P 0.05). Moreover, after pooling all female versus male participants, IET induced a 6.9-mmHg reduction in systolic blood pressure in female participants, but only a 1.5-mmHg reduction in systolic blood pressure in male participants, although the difference was not significant. An IET intensity between 20%EMGpeak and 30%EMGpeak is sufficient to elicit significant resting blood pressure reductions in a short-term training period (3 weeks). In addition, sexual dimorphism may exist in the magnitude of reductions, but further work is required to confirm this possibility, which could be important in understanding the mechanisms responsible

    Mitochondrial precursor proteins are imported through a hydrophilic membrane environment

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    We have analyzed how translocation intermediates of imported mitochondrial precursor proteins, which span contact sites, interact with the mitochondrial membranes. F1-ATPase subunit β(F1β) was trapped at contact sites by importing it into Neurospora mitochondria in the presence of low levels of nucleoside triphosphates. This F1β translocation intermediate could be extracted from the membranes by treatment with protein denaturants such as alkaline pH or urea. By performing import at low temperatures, the ADP/ATP carrier was accumulated in contact sites of Neurospora mitochondria and cytochrome b2 in contact sites of yeast mitochondria. These translocation intermediates were also extractable from the membranes at alkaline pH. Thus, translocation of precursor proteins across mitochondrial membranes seems to occur through an environment which is accessible to aqueous perturbants. We propose that proteinaceous structures are essential components of a translocation apparatus present in contact sites

    Annihilation of NMSSM neutralinos in the Sun and neutrino telescope limits

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    We investigate neutralino dark matter in the framework of NMSSM performing a scan over its parameter space and calculating neutralino capture and annihilation rates in the Sun. We discuss the prospects of searches for neutralino dark matter in neutrino experiments depending on neutralino content and its main annihilation channel. We recalculate the upper limits on neutralino-proton elastic cross sections directly from neutrino telescopes upper bounds on annihilation rates in the Sun. This procedure has advantages as compared with corresponding recalcalations from the limits on muon flux, namely, it is independent on details of the experiment and the recalculation coefficients are universal for any kind of WIMP dark matter models. We derive 90% c.l. upper limits on neutralino-proton cross sections from the results of the Baksan Underground Scintillator Telescope.Comment: 28 pages, 16 figures, accepted for publication in JCAP, references adde

    Energy-dependent reversal of the cytochrome oxidase reaction.

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    Annihilation vs. Decay: Constraining dark matter properties from a gamma-ray detection

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    Most proposed dark matter candidates are stable and are produced thermally in the early Universe. However, there is also the possibility of unstable (but long-lived) dark matter, produced thermally or otherwise. We propose a strategy to distinguish between dark matter annihilation and/or decay in the case that a clear signal is detected in gamma-ray observations of Milky Way dwarf spheroidal galaxies with gamma-ray experiments. The sole measurement of the energy spectrum of an indirect signal would render the discrimination between these cases impossible. We show that by examining the dependence of the intensity and energy spectrum on the angular distribution of the emission, the origin could be identified as decay, annihilation, or both. In addition, once the type of signal is established, we show how these measurements could help to extract information about the dark matter properties, including mass, annihilation cross section, lifetime, dominant annihilation and decay channels, and the presence of substructure. Although an application of the approach presented here would likely be feasible with current experiments only for very optimistic dark matter scenarios, the improved sensitivity of upcoming experiments could enable this technique to be used to study a wider range of dark matter models.Comment: 29 pp, 8 figs; replaced to match published version (minor changes and some new references

    Redox-induced activation of the proton pump in the respiratory complex I

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    Significance Complex I is a redox-driven proton pump, central for aerobic energy transduction. We show here by large-scale quantum and classical molecular simulations how reduction of quinone (Q) in the hydrophilic domain of complex I activates the proton pump in the membrane domain. Our simulations indicate that reduction of Q leads to local charge redistributions that trigger conformational changes via an array of alternating charged residues in the membrane domain, nearly 40 Å away. These mechanistic observations are supported by site-directed mutagenesis of a key residue triggering the activation process. The combined data provide molecular insight into how the long-range energy transduction is accomplished by complex I.</jats:p

    Young people, crime and school exclusion: a case of some surprises

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    During the 1990s the number of young people being permanently excluded from schools in England and Wales increased dramatically from 2,910 (1990/91) to a peak of 12,700 (1996/97). Coinciding with this rise was a resurgence of the debate centring on lawless and delinquent youth. With the publication of Young People and Crime (Graham and Bowling 1995) and Misspent Youth (Audit Commission 1996) the 'common sense assumption' that exclusion from school inexorably promoted crime received wide support, with the school excludee portrayed as another latter day 'folk devil'. This article explores the link between school exclusion and juvenile crime, and offers some key findings from a research study undertaken with 56 young people who had experience of being excluded from school. Self-report interview questions reveal that whilst 40 of the young people had offended, 90% (36) reported that the onset of their offending commenced prior to their first exclusion. Moreover, 50 (89.2% of the total number of young people in the sample), stated that they were no more likely to offend subsequent to being excluded and 31 (55.4%) stated that they were less likely to offend during their exclusion period. Often, this was because on being excluded, they were 'grounded' by their parents

    Healthy full-term infants' brain responses to emotionally and linguistically relevant sounds using a multi-feature mismatch negativity (MMN) paradigm

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    We evaluated the feasibility of a multi-feature mismatch negativity (MMN) paradigm in studying auditory processing of healthy newborns. The aim was to examine the automatic change-detection and processing of semantic and emotional information in speech in newborns. Brain responses of 202 healthy newborns were recorded with a multi-feature paradigm including a Finnish bi-syllabic pseudo-word/ta-ta/as a standard stimulus, six linguistically relevant deviant stimuli and three emotionally relevant stimuli (happy, sad, angry). Clear responses to emotional sounds were found already at the early latency window 100-200 ms, whereas responses to linguistically relevant minor changes and emotional stimuli at the later latency window 300-500 ms did not reach significance. Moreover, significant interaction between gender and emotional stimuli was found in the early latency window. Further studies on using multi-feature paradigms with linguistic and emotional stimuli in newborns are needed, especially those containing of follow-ups, enabling the assessment of the predictive value of early variations between subjects.Peer reviewe
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