1,741 research outputs found

    Epicardial myocardial strain abnormalities may identify the earliest stages of arrhythmogenic cardiomyopathy.

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    The aim of this cohort study was to evaluate the value of echocardiographic multilayer strain analysis in the identification of arrhythmogenic cardiomyopathy (AC) in its earliest stages in which sudden cardiac death can occurs. Twenty seven asymptomatic relatives of AC probands (mean age 39.6 ± 19.5 years, 37 % male) with a desmosomal pathogenic mutation but no additional criteria for AC (group II) were compared to age and sex-matched healthy controls (group I). In addition, 70 patients harboring a pathogenic desmosomal mutation with "definitive" diagnosis of AC (group IV), and 19 subjects with "borderline" diagnosis (group III) were also studied. A standard echocardiographic evaluation plus left (LV) and right ventricular global and regional transmural, endocardial, and epicardial longitudinal strain (LS) analysis, was performed. In group II, while LV ejection fraction, fractional shortening, and S' were not significantly reduced compared to controls, transmural global LS was significantly reduced to 19.3 ± 1.8 % in group II versus 20.9 ± 1.1 % in controls (p = 0.0003). Compared to controls, group II presented significant (p < 0.05) regional LS decrease in the basal infero-lateral, antero-lateral, latero-apical, infero-septal, and septo-apical segments. Moreover, LS of the latero-apical and the basal antero-lateral segments was significantly altered in the epicardium (p < 0.05) but not significantly in the endocardium. Global and regional LV LS analysis allows detection of AC in an early or non-diagnostic stage of the disease. Moreover, epicardial LS analysis allows the detection of abnormalities earlier than endocardial LS

    Tracing magnetism and pairing in FeTe-based systems

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    In order to examine the interplay between magnetism and superconductivity, we monitor the non- superconducting chalcogenide FeTe and follow its transitions under insertion of oxygen, doping with Se and vacancies of Fe using spin-polarized band structure methods (LSDA with GGA) starting from the collinear and bicollinear magnetic arrangements. We use a supercell of Fe8Te8 as our starting point so that it can capture local changes in magnetic moments. The calculated values of magnetic moments agree well with available experimental data while oxygen insertions lead to significant changes in the bicollinear or collinear magnetic moments. The total energies of these systems indicate that the collinear-derived structure is the more favorable one prior to a possible superconducting transition. Using a 8-site Betts-cluster-based lattice and the Hubbard model, we show why this structure favors electron or hole pairing and provides clues to a common understanding of charge and spin pairing in the cuprates, pnictides and chalcogenides

    Fluctuations in granular gases

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    A driven granular material, e.g. a vibrated box full of sand, is a stationary system which may be very far from equilibrium. The standard equilibrium statistical mechanics is therefore inadequate to describe fluctuations in such a system. Here we present numerical and analytical results concerning energy and injected power fluctuations. In the first part we explain how the study of the probability density function (pdf) of the fluctuations of total energy is related to the characterization of velocity correlations. Two different regimes are addressed: the gas driven at the boundaries and the homogeneously driven gas. In a granular gas, due to non-Gaussianity of the velocity pdf or lack of homogeneity in hydrodynamics profiles, even in the absence of velocity correlations, the fluctuations of total energy are non-trivial and may lead to erroneous conclusions about the role of correlations. In the second part of the chapter we take into consideration the fluctuations of injected power in driven granular gas models. Recently, real and numerical experiments have been interpreted as evidence that the fluctuations of power injection seem to satisfy the Gallavotti-Cohen Fluctuation Relation. We will discuss an alternative interpretation of such results which invalidates the Gallavotti-Cohen symmetry. Moreover, starting from the Liouville equation and using techniques from large deviation theory, the general validity of a Fluctuation Relation for power injection in driven granular gases is questioned. Finally a functional is defined using the Lebowitz-Spohn approach for Markov processes applied to the linear inelastic Boltzmann equation relevant to describe the motion of a tracer particle. Such a functional results to be different from injected power and to satisfy a Fluctuation Relation.Comment: 40 pages, 18 figure

    Top-up operation at Pohang Light Source-II

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    After three years of upgrading work, PLS-II (S. Shin, Commissioning of the PLS-II, JINST, January 2013) is now successfully operating. The top-up operation of the 3 GeV linear accelerator had to be delayed because of some challenges encountered, and PLS-II was run in decay mode at the beginning in March 2012. The main difficulties encountered in the top-up operation of PLS-II are different levels between the linear accelerator and the storage ring, the 14 narrow gap in-vacuum undulators in operation, and the full energy injection by 3 GeV linear accelerator. Large vertical emittance and energy jitter of the linac were the major obstacles that called for careful control of injected beam to reduce beam loss in the storage ring during injection. The following measures were taken to resolve these problems: (1) The high resolution Libera BPM (see http://www.i-tech.si) was implemented to measure the beam trajectory and energy. (2) Three slit systems were installed to filter the beam edge. (3) De-Qing circuit was applied to the modulator system to improve the energy stability of injected beam. As a result, the radiation by beam loss during injection is reduced drastically, and the top-up mode has been successfully operating since 19th March 2013. In this paper, we describe the experimental results of the PLS-II top-up operation and the improvement plan. (C) 2014 AIP Publishing LLC.open111011sciescopu

    Statewide Systematic Evaluation of Sudden, Unexpected Infant Death Classification: Results from a National Pilot Project

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    The Centers for Disease Control and Prevention funded seven states, including Kentucky, to clarify statewide death certification practices in sudden, unexpected infant death and compare state performances with national expectations. Accurate assignment of the cause and manner of death in cases of sudden, unexpected infant death is critical for accurate vital statistics data to direct limited resources to appropriate targets, and to implement optimal and safe risk reduction strategies. The primary objectives are to (1) Compare SUID death certifications recommended by the KY medical examiners with the stated cause of death text field on the hard copy death electronic death certificates and (2) Compare KY and national SUID rates. Causes of death for SUID cases recommended by the medical examiners and those appearing on the hard copy and electronic death certificates in KY were collected retrospectively for 2004 and 2005. Medical examiner recommendations were based upon a classification scheme devised by them in 2003. Coroners hard copy death certificates and the cause of death rates in KY were compared to those occurring nationally. Eleven percent of infants dying suddenly and unexpectedly did not undergo autopsy during the study interval. The KY 2003 classification scheme for SIDS is at variance with the NICHD and San Diego SIDS definitions. Significant differences in causes of death recommended by medical examiners and those appearing on the hard copy and electronic death certificates were identified. SIDS rates increased in KY in contrast to decreasing rates nationally. Nationwide adoption of a widely used SIDS definition, such as that proposed in San Diego in 2004 as well as legislation by states to ensure autopsy in all cases of sudden unexpected infant death are recommended. Medical examiners’ recommendations for cause of death should appear on death certificates. Multidisciplinary pediatric death review teams prospectively evaluating cases before death certification is recommended. Research into other jurisdictions death certification process is encouraged

    E2F and p53 Induce Apoptosis Independently during Drosophila Development but Intersect in the Context of DNA Damage

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    In mammalian cells, RB/E2F and p53 are intimately connected, and crosstalk between these pathways is critical for the induction of cell cycle arrest or cell death in response to cellular stresses. Here we have investigated the genetic interactions between RBF/E2F and p53 pathways during Drosophila development. Unexpectedly, we find that the pro-apoptotic activities of E2F and p53 are independent of one another when examined in the context of Drosophila development: apoptosis induced by the deregulation of dE2F1, or by the overexpression of dE2F1, is unaffected by the elimination of dp53; conversely, dp53-induced phenotypes are unaffected by the elimination of dE2F activity. However, dE2F and dp53 converge in the context of a DNA damage response. Both dE2F1/dDP and dp53 are required for DNA damage-induced cell death, and the analysis of rbf1 mutant eye discs indicates that dE2F1/dDP and dp53 cooperatively promote cell death in irradiated discs. In this context, the further deregulation in the expression of pro-apoptotic genes generates an additional sensitivity to apoptosis that requires both dE2F/dDP and dp53 activity. This sensitivity differs from DNA damage-induced apoptosis in wild-type discs (and from dE2F/dDP-induced apoptosis in un-irradiated rbf1 mutant eye discs) by being dependent on both hid and reaper. These results show that pro-apoptotic activities of dE2F1 and dp53 are surprisingly separable: dp53 is required for dE2F-dependent apoptosis in the response to DNA damage, but it is not required for dE2F-dependent apoptosis caused simply by the inactivation of rbf1

    Acute Intrathoracic Gastric Volvulus due to Diaphragmatic Hernia: A Rare Emergency Easily Overlooked

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    Acute intrathoracic gastric volvulus occurs when the stomach undergoes organoaxial torsion in the chest due to either concomitant enlargement of the hiatus or a diaphragmatic hernia. Iatrogenic diaphragmatic hernia can occur after hiatal hernia repair and other surgical procedures, such as nephrectomy, esophagogastrectomy and splenopancreatectomy. We describe a 49-year-old woman who presented to our emergency department with acute moderate epigastric soreness and vomiting. She had undergone extensive gynecologic surgery including splenectomy 1 year before. The chest radiograph obtained in the emergency department demonstrated an elevated gastric air-fluid level in the left lower lung field. An urgent gastroscopy showed twisted structural abnormality of the stomach body. A computed tomography scan demonstrated the distended stomach, located in the left lower hemithorax through a left diaphragmatic defect. Emergent transthoracic repair was performed. Postoperative recovery was uneventful, and the patient did not experience any pain or difficulty with eating

    Single Gene Deletions of Orexin, Leptin, Neuropeptide Y, and Ghrelin Do Not Appreciably Alter Food Anticipatory Activity in Mice

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    Timing activity to match resource availability is a widely conserved ability in nature. Scheduled feeding of a limited amount of food induces increased activity prior to feeding time in animals as diverse as fish and rodents. Typically, food anticipatory activity (FAA) involves temporally restricting unlimited food access (RF) to several hours in the middle of the light cycle, which is a time of day when rodents are not normally active. We compared this model to calorie restriction (CR), giving the mice 60% of their normal daily calorie intake at the same time each day. Measurement of body temperature and home cage behaviors suggests that the RF and CR models are very similar but CR has the advantage of a clearly defined food intake and more stable mean body temperature. Using the CR model, we then attempted to verify the published result that orexin deletion diminishes food anticipatory activity (FAA) but observed little to no diminution in the response to CR and, surprisingly, that orexin KO mice are refractory to body weight loss on a CR diet. Next we tested the orexigenic neuropeptide Y (NPY) and ghrelin and the anorexigenic hormone, leptin, using mouse mutants. NPY deletion did not alter the behavior or physiological response to CR. Leptin deletion impaired FAA in terms of some activity measures, such as walking and rearing, but did not substantially diminish hanging behavior preceding feeding time, suggesting that leptin knockout mice do anticipate daily meal time but do not manifest the full spectrum of activities that typify FAA. Ghrelin knockout mice do not have impaired FAA on a CR diet. Collectively, these results suggest that the individual hormones and neuropepetides tested do not regulate FAA by acting individually but this does not rule out the possibility of their concerted action in mediating FAA
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