1,939 research outputs found

    Hyperemesis gravidarum: current perspectives.

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    Hyperemesis gravidarum is a complex condition with a multifactorial etiology characterized by severe intractable nausea and vomiting. Despite a high prevalence, studies exploring underlying etiology and treatments are limited. We performed a literature review, focusing on articles published over the last 10 years, to examine current perspectives and recent developments in hyperemesis gravidarum

    Evidence of a universal and isotropic 2\Delta/kBTC ratio in 122-type iron pnictide superconductors over a wide doping range

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    We have systematically investigated the doping and the directional dependence of the gap structure in the 122-type iron pnictide superconductors by point contact Andreev reflection spectroscopy. The studies were performed on single crystals of Ba1-xKxFe2As2 (x = 0.29, 0.49, and 0.77) and SrFe1.74Co0.26As2 with a sharp tip of Pb or Au pressed along the c-axis or the ab-plane direction. The conductance spectra obtained on highly transparent contacts clearly show evidence of a robust superconducting gap. The normalized curves can be well described by the Blonder-Tinkham-Klapwijk model with a lifetime broadening. The determined gap value scales very well with the transition temperature, giving the 2{\Delta}/kBTC value of ~ 3.1. The results suggest the presence of a universal coupling behavior in this class of iron pnictides over a broad doping range and independent of the sign of the doping. Moreover, conductance spectra obtained on c-axis junctions and ab-plane junctions indicate that the observed gap is isotropic in these superconductors

    The Full-sky Astrometric Mapping Explorer -- Astrometry for the New Millennium

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    FAME is designed to perform an all-sky, astrometric survey with unprecedented accuracy. It will create a rigid astrometric catalog of 4x10^7 stars with 5 < m_V < 15. For bright stars, 5 < m_V < 9, FAME will determine positions and parallaxes accurate to < 50 microarcseconds, with proper motion errors < 50 microarcseconds/year. For fainter stars, 9 < m_V < 15, FAME will determine positions and parallaxes accurate to < 500 microarcseconds, with proper motion errors < 500 microarcseconds/year. It will also collect photometric data on these 4 x 10^7 stars in four Sloan DSS colors.Comment: 6 pages, 4 figures, to appear in "Working on the Fringe

    Fractional Synthetic Rate and Markers of Protein Turnover are Altered in the Diaphragms of Cachectic Mice

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    Cancer cachexia, a wasting syndrome characterized by rapid skeletal muscle wasting and fat loss, directly accounts for up to 20-40% of cancer-related deaths. All muscles, including respiratory muscles, are susceptible to atrophy because cancer cachexia is a systemic disease. Atrophy of the primary breathing muscle, the diaphragm, can lead to respiratory distress, which is commonly associated with a cachectic phenotype. Indeed, the diaphragm is more susceptible to atrophy in certain conditions, but little is known about the effects of cancer-cachexia on protein turnover in the diaphragm. Therefore, investigations into the alterations in protein turnover could provide insight to the molecular events and provide valuable information in the search for therapeutic targets. PURPOSE: The purpose of this study was to describe changes in diaphragmatic protein synthesis and molecular markers of synthesis and degradation during the progression of cancer cachexia. METHODS: C57BL6/J mice (8 wks old) were implanted with 1X106 Lewis Lung Carcinoma cells (LLC) or Phosphate-Buffered Saline (PBS, control). Tumors developed over a 1-4 wk time course and diaphragms were harvested at each time point (1, 2, 3, or 4 wks). Fractional synthetic rates (FSR) were determined using deuterium incorporation into muscle. Selected markers of protein synthesis and degradation pathways were analyzed by immunoblot analysis. One-Way ANOVA was used for statistical analyses, with significance set at pRESULTS: FSR trended downward over time, but did not reach significance. Similar to FSR, anabolic signaling markers (4EBP-1, ERK1/2, Deptor) did not demonstrate significant differences. p62, an autophagic degradation marker, was significantly less than PBS in 3 wk diaphragms (

    Boundary Effective Field Theory and Trans-Planckian Perturbations: Astrophysical Implications

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    We contrast two approaches to calculating trans-Planckian corrections to the inflationary perturbation spectrum: the New Physics Hypersurface [NPH] model, in which modes are normalized when their physical wavelength first exceeds a critical value, and the Boundary Effective Field Theory [BEFT] approach, where the initial conditions for all modes are set at the same time, and modified by higher dimensional operators enumerated via an effective field theory calculation. We show that these two approaches -- as currently implemented -- lead to radically different expectations for the trans-Planckian corrections to the CMB and emphasize that in the BEFT formalism we expect the perturbation spectrum to be dominated by quantum gravity corrections for all scales shorter than some critical value. Conversely, in the NPH case the quantum effects only dominate the longest modes that are typically much larger than the present horizon size. Furthermore, the onset of the breakdown in the standard inflationary perturbation calculation predicted by the BEFT formalism is likely to be associated with a feature in the perturbation spectrum, and we discuss the observational signatures of this feature in both CMB and large scale structure observations. Finally, we discuss possible modifications to both calculational frameworks that would resolve the contradictions identified here.Comment: Reworded commentary, reference added (v2) References added (v3

    EXCEDE Technology Development III: First Vacuum Tests

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    This paper is the third in the series on the technology development for the EXCEDE (EXoplanetary Circumstellar Environments and Disk Explorer) mission concept, which in 2011 was selected by NASA's Explorer program for technology development (Category III). EXCEDE is a 0.7m space telescope concept designed to achieve raw contrasts of 1e6 at an inner working angle of 1.2 l/D and 1e7 at 2 l/D and beyond. This will allow it to directly detect and spatially resolve low surface brightness circumstellar debris disks as well as image giant planets as close as in the habitable zones of their host stars. In addition to doing fundamental science on debris disks, EXCEDE will also serve as a technological and scientific precursor for any future exo-Earth imaging mission. EXCEDE uses a Starlight Suppression System (SSS) based on the PIAA coronagraph, enabling aggressive performance. We report on our continuing progress of developing the SSS for EXCEDE, and in particular (a) the reconfiguration of our system into a more flight-like layout, with an upstream deformable mirror and an inverse PIAA system, as well as a LOWFS, and (b) testing this system in a vacuum chamber, including IWA, contrast, and stability performance. The results achieved so far are 2.9e-7 contrast between 1.2-2.0 l/D and 9.7e-8 contrast between 2.0-6.0 l/D in monochromatic light; as well as 1.4e-6 between 2.0-6.0 l/D in a 10% band, all with a PIAA coronagraph operating at an inner working angle of 1.2 l/D. This constitutes better contrast than EXCEDE requirements (in those regions) in monochromatic light, and progress towards requirements in broadband light. Even though this technology development is primarily targeted towards EXCEDE, it is also germane to any exoplanet direct imaging space-based telescopes because of the many challenges common to different coronagraph architectures and mission requirements.Comment: 12 pages, 12 figures, to be published in proceedings of SPIE Astronomical Telescopes + Instrumentation (2014

    Disuse Atrophy Occurs Without a Change in Mitochondrial Respiratory Control Ratio During Hindlimb Unloading in Mice

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    Skeletal muscle atrophy commonly occurs during prolonged periods of inactivity, however, the precise mechanisms that cause muscle atrophy have yet to be determined. Specifically, a controversy exists on whether mitochondrial dysfunction is a cause or consequence of disuse muscle atrophy. PURPOSE: The purpose of this study was to determine if a change in the respiratory control ratio, which is a ratio of maximal O2 respiration to leak respiration, could be detected prior to muscle atrophy in a time-course study in mice. METHODS: Disuse atrophy was induced using hindlimb unloading (HU) in adult, C57BL/6J male mice for 0 (control), 1, 2, 3, or 7 days (n=~6-8/group). Following completion, gastrocnemius and soleus muscles were weighed and assessed for mitochondrial function in permeabilized muscle fibers. Here, we define mitochondrial function as the respiratory control ratio (RCR) determined by maximal ADP stimulated respiration (State 3) divided by leak or ATP synthase inhibited (state 4) respiration. A one-way ANOVA was used to determine differences between means. When significant F ratios were found, a Tukey post-hoc was used to compare differences between means. Values presented are mean ± standard error RESULTS: In both the gastrocnemius and soleus, muscle mass was not significantly different from control at day 1, but was significantly lower at 2, 3, and 7-day timepoints. In contrast, there was no significant difference in RCR in gastrocnemius (control 3.11±0.20, 1 day 2.96±0.60, 2 day 3.07±0.31, 3 day 3.08±0.25, 7 day 3.41± .29) or soleus (control 2.33±0.33, 1 day 2.77±0.33, 2 day 3.03±0.51, 3 day 2.93±0.30, 7 day 2.78±0.48). CONCLUSION: It is well established that HU causes rapid muscle atrophy. These data support mitochondrial RCR does decrease before muscle atrophy in either gastrocnemius or soleus muscle, and therefore may not be a primary cause of HU-induced muscle atrophy in mice
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