2,556 research outputs found

    Esophageal perforation caused by external air-blast injury

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    <p>Abstract</p> <p>Background</p> <p>Esophageal perforation after external air-blast trauma is rarely presented in the emergency room. The diagnosis is often delayed more than 24 hours.</p> <p>Methods</p> <p>We review the literature and report a case of esophageal perforation caused by external air-blast injury.</p> <p>Results</p> <p>Including the present case, a total of 5 cases of esophageal perforation were caused by external air-blast injury in English literature. Of them, the common presentations were chest pain and dyspnea. The treatment methods varied with each case. One patient died before diagnosis of esophageal perforation and the others survived after proper surgical management.</p> <p>Conclusions</p> <p>Early diagnosis and proper surgical management can reduce the morbidity and mortality of patients who suffered from esophageal perforation caused by external air-blast injury.</p

    Transitions/relaxations in polyester adhesive/PET system

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    The correlations between the transitions and the dielectric relaxation processes of the oriented poly(ethylene terephthalate) (PET) pre-impregnated of the polyester thermoplastic adhesive have been investigated by differential scanning calorimetry (DSC) and dynamic dielectric spectroscopy (DDS). The thermoplastic polyester adhesive and the oriented PET films have been studied as reference samples. This study evidences that the adhesive chain segments is responsible for the physical structure evolution in the PET-oriented film. The transitions and dielectric relaxation modes’ evolutions in the glass transition region appear characteristic of the interphase between adhesive and PET film, which is discussed in terms of molecular mobility. The storage at room temperature of the adhesive tape involves the heterogeneity of the physical structure, characterized by glass transition dissociation. Thus, the correlation between the transitions and the dielectric relaxation processes evidences a segregation of the amorphous phases. Therefore, the physical structure and the properties of the material have been linked to the chemical characteristics

    TMS-evoked EEG potentials demonstrate altered cortical excitability in migraine with aura

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    Migraine is associated with altered sensory processing, that may be evident as changes in cortical responsivity due to altered excitability, especially in migraine with aura. Cortical excitability can be directly assessed by combining transcranial magnetic stimulation with electroencephalography (TMS-EEG). We measured TMS evoked potential (TEP) amplitude and response consistency as these measures have been linked to cortical excitability but were not yet reported in migraine. We recorded 64-channel EEG during single-pulse TMS on the vertex interictally in 10 people with migraine with aura and 10 healthy controls matched for age, sex and resting motor threshold. On average 160 pulses around resting motor threshold were delivered through a circular coil in clockwise and counterclockwise direction. Trial-averaged TEP responses, frequency spectra and phase clustering (over the entire scalp as well as in frontal, central and occipital midline electrode clusters) were compared between groups, including comparison to sham-stimulation evoked responses. Migraine and control groups had a similar distribution of TEP waveforms over the scalp. In migraine with aura, TEP responses showed reduced amplitude around the frontal and occipital N100 peaks. For the migraine and control groups, responses over the scalp were affected by current direction for the primary motor cortex, somatosensory cortex and sensory association areas, but not for frontal, central or occipital midline clusters. This study provides evidence of altered TEP responses in-between attacks in migraine with aura. Decreased TEP responses around the N100 peak may be indicative of reduced cortical GABA-mediated inhibition and expand observations on enhanced cortical excitability from earlier migraine studies using more indirect measurements

    A giant comet-like cloud of hydrogen escaping the warm Neptune-mass exoplanet GJ 436b

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    Exoplanets orbiting close to their parent stars could lose some fraction of their atmospheres because of the extreme irradiation. Atmospheric mass loss primarily affects low-mass exoplanets, leading to suggest that hot rocky planets might have begun as Neptune-like, but subsequently lost all of their atmospheres; however, no confident measurements have hitherto been available. The signature of this loss could be observed in the ultraviolet spectrum, when the planet and its escaping atmosphere transit the star, giving rise to deeper and longer transit signatures than in the optical spectrum. Here we report that in the ultraviolet the Neptune-mass exoplanet GJ 436b (also known as Gliese 436b) has transit depths of 56.3 +/- 3.5% (1 sigma), far beyond the 0.69% optical transit depth. The ultraviolet transits repeatedly start ~2 h before, and end >3 h after the ~1 h optical transit, which is substantially different from one previous claim (based on an inaccurate ephemeris). We infer from this that the planet is surrounded and trailed by a large exospheric cloud composed mainly of hydrogen atoms. We estimate a mass-loss rate in the range of ~10^8-10^9 g/s, which today is far too small to deplete the atmosphere of a Neptune-like planet in the lifetime of the parent star, but would have been much greater in the past.Comment: Published in Nature on 25 June 2015. Preprint is 28 pages, 12 figures, 2 table

    ASIME 2018 White Paper. In-Space Utilisation of Asteroids: Asteroid Composition -- Answers to Questions from the Asteroid Miners

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    In keeping with the Luxembourg government's initiative to support the future use of space resources, ASIME 2018 was held in Belval, Luxembourg on April 16-17, 2018. The goal of ASIME 2018: Asteroid Intersections with Mine Engineering, was to focus on asteroid composition for advancing the asteroid in-space resource utilisation domain. What do we know about asteroid composition from remote-sensing observations? What are the potential caveats in the interpretation of Earth-based spectral observations? What are the next steps to improve our knowledge on asteroid composition by means of ground-based and space-based observations and asteroid rendez-vous and sample return missions? How can asteroid mining companies use this knowledge? ASIME 2018 was a two-day workshop of almost 70 scientists and engineers in the context of the engineering needs of space missions with in-space asteroid utilisation. The 21 Questions from the asteroid mining companies were sorted into the four asteroid science themes: 1) Potential Targets, 2) Asteroid-Meteorite Links, 3) In-Situ Measurements and 4) Laboratory Measurements. The Answers to those Questions were provided by the scientists with their conference presentations and collected by A. Graps or edited directly into an open-access collaborative Google document or inserted by A. Graps using additional reference materials. During the ASIME 2018, first day and second day Wrap-Ups, the answers to the questions were discussed further. New readers to the asteroid mining topic may find the Conversation boxes and the Mission Design discussions especially interesting.Comment: Outcome from the ASIME 2018: Asteroid Intersections with Mine Engineering, Luxembourg. April 16-17, 2018. 65 Pages. arXiv admin note: substantial text overlap with arXiv:1612.0070

    An international comparative study of blood pressure in populations of European vs. African descent

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    Background: The consistent finding of higher prevalence of hypertension in US blacks compared to whites has led to speculation that African-origin populations are particularly susceptible to this condition. Large surveys now provide new information on this issue. Methods: Using a standardized analysis strategy we examined prevalence estimates for 8 white and 3 black populations (N = 85,000 participants). Results: The range in hypertension prevalence was from 27 to 55% for whites and 14 to 44% for blacks. Conclusions: These data demonstrate that not only is there a wide variation in hypertension prevalence among both racial groups, the rates among blacks are not unusually high when viewed internationally. These data suggest that the impact of environmental factors among both populations may have been under-appreciated

    Correlations of Behavioral Deficits with Brain Pathology Assessed through Longitudinal MRI and Histopathology in the R6/2 Mouse Model of HD

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    Huntington's disease (HD) is caused by the expansion of a CAG repeat in the huntingtin (HTT) gene. The R6/2 mouse model of HD expresses a mutant version of exon 1 HTT and develops motor and cognitive impairments, a widespread huntingtin (HTT) aggregate pathology and brain atrophy. Despite the vast number of studies that have been performed on this model, the association between the molecular and cellular neuropathology with brain atrophy, and with the development of behavioral phenotypes remains poorly understood. In an attempt to link these factors, we have performed longitudinal assessments of behavior (rotarod, open field, passive avoidance) and of regional brain abnormalities determined through magnetic resonance imaging (MRI) (whole brain, striatum, cortex, hippocampus, corpus callosum), as well as an end-stage histological assessment. Detailed correlative analyses of these three measures were then performed. We found a gender-dependent emergence of motor impairments that was associated with an age-related loss of regional brain volumes. MRI measurements further indicated that there was no striatal atrophy, but rather a lack of striatal growth beyond 8 weeks of age. T2 relaxivity further indicated tissue-level changes within brain regions. Despite these dramatic motor and neuroanatomical abnormalities, R6/2 mice did not exhibit neuronal loss in the striatum or motor cortex, although there was a significant increase in neuronal density due to tissue atrophy. The deposition of the mutant HTT (mHTT) protein, the hallmark of HD molecular pathology, was widely distributed throughout the brain. End-stage histopathological assessments were not found to be as robustly correlated with the longitudinal measures of brain atrophy or motor impairments. In conclusion, modeling pre-manifest and early progression of the disease in more slowly progressing animal models will be key to establishing which changes are causally related. © 2013 Rattray et al

    Transcriptomic Analysis of Host Immune and Cell Death Responses Associated with the Influenza A Virus PB1-F2 Protein

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    Airway inflammation plays a major role in the pathogenesis of influenza viruses and can lead to a fatal outcome. One of the challenging objectives in the field of influenza research is the identification of the molecular bases associated to the immunopathological disorders developed during infection. While its precise function in the virus cycle is still unclear, the viral protein PB1-F2 is proposed to exert a deleterious activity within the infected host. Using an engineered recombinant virus unable to express PB1-F2 and its wild-type homolog, we analyzed and compared the pathogenicity and host response developed by the two viruses in a mouse model. We confirmed that the deletion of PB1-F2 renders the virus less virulent. The global transcriptomic analyses of the infected lungs revealed a potent impact of PB1-F2 on the response developed by the host. Thus, after two days post-infection, PB1-F2 invalidation severely decreased the number of genes activated by the host. PB1-F2 expression induced an increase in the number and level of expression of activated genes linked to cell death, inflammatory response and neutrophil chemotaxis. When generating interactive gene networks specific to PB1-F2, we identified IFN-γ as a central regulator of PB1-F2-regulated genes. The enhanced cell death of airway-recruited leukocytes was evidenced using an apoptosis assay, confirming the pro-apoptotic properties of PB1-F2. Using a NF-kB luciferase adenoviral vector, we were able to quantify in vivo the implication of NF-kB in the inflammation mediated by the influenza virus infection; we found that PB1-F2 expression intensifies the NF-kB activity. Finally, we quantified the neutrophil recruitment within the airways, and showed that this type of leukocyte is more abundant during the infection of the wild-type virus. Collectively, these data demonstrate that PB1-F2 strongly influences the early host response during IAV infection and provides new insights into the mechanisms by which PB1-F2 mediates virulence
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