967 research outputs found

    Prospective study of 310 patients: can early CT predict the severity of acute pancreatitis?

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    Background: This study was designed to determine the most important early CT parameters predictive of acute pancreatitis severity. Methods: Three hundred and seventy-one consecutive patients with acute abdominal pain and hyperamylasemia were enrolled. Three hundred and ten of the 371 patients met our inclusion criteria. Acute pancreatitis severity was evaluated using the 1992 Atlanta criteria. Different CT parameters were reported from the admission abdominal CT by two radiologists blinded from any clinical parameter, but the patients' age and gender. These variables were fitted in a binary logistic regression model. Results: Acute pancreatitis was mild in 80% cases, severe in 20% cases and lethal in 12.69% cases. The following CT parameters were significantly associated with the severity of acute pancreatitis: the objective size of the pancreas (P=0.001), the peripancreatic fat abnormalities (P=0.001) and the extent of necrosis (P=0.007). Moreover, the age of the patient revealed itself a highly significant (P=0.001) indicator of disease severity. The association of the four CT criteria eventually showed a sensitivity of 73% and a specificity of 81% to predict acute pancreatitis severity. Conclusion: Although these criteria correlated with disease severity, our study identified that morphological CT criteria cannot be used to triage patients with severe and mild acute pancreatiti

    Assessing the Device-performance Impacts of Structural Defects with TCAD Modeling

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    Advanced solar cell architectures like passivated emitter and rear (PERC) and heterojunction with intrinsic thin layer (HIT) are increasingly sensitive to bulk recombination. Present device models consider homogeneous bulk lifetime, which does not accurately reflect the effects of heterogeneously distributed defects. To determine the efficiency potential of multicrystalline silicon (mc-Si) in next-generation architectures, we present a higher-dimensional numerical simulation study of the impacts of structural defects on solar cell performance. We simulate these defects as an interfacial density of traps with a single mid-gap energy level using Shockley-Read-Hall (SRH) statistics. To account for enhanced recombination at the structural defects, we apply a linear scaling to the majority-carrier capture cross-section and scale the minority-carrier capture cross-section with the inverse of the line density of traps. At 300 K, our simulations of carrier occupation and recombination rate match literature electron-beam-induced current (EBIC) data and first-principles calculations of carrier capture, emission, and recombination for all the energy levels associated with dislocations decorated with metal impurities. We implement our model in Sentaurus Device, determining the losses across different device architectures for varying impurity decoration of grain boundaries.American Society for Engineering Education. National Defense Science and Engineering Graduate FellowshipNational Science Foundation (U.S.). Engineering Research Centers Program (Cooperative Agreement EEC-1041895

    Insulin secretion from human beta cells is heterogeneous and dependent on cell-to-cell contacts

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    Aims/hypothesis: We assessed the heterogeneity of insulin secretion from human isolated beta cells and its regulation by cell-to-cell contacts. Methods: Insulin secretion from single and paired cells was assessed by a reverse haemolytic plaque assay. The percentage of plaque-forming cells, the mean plaque area and the total plaque development were evaluated after 1h of stimulation with different secretagogues. Results: Not all beta cells were surrounded by a haemolytic plaque under all conditions tested. A small fraction of the beta cell population (20%) secreted more than 90% and 70% of total insulin at 2.2 and 22.2mmol/l glucose, respectively. Plaque-forming cells, mean plaque area and total plaque development were increased at 12.2 and 22.2 compared with 2.2mmol/l glucose. Insulin secretion of single beta cells was similar at 12.2 and 22.2mmol/l glucose. Insulin secretion of beta cell pairs was increased compared with that of single beta cells and was higher at 22.2 than at 12.2mmol/l glucose. Insulin secretion of beta cells in contact with alpha cells was also increased compared with single beta cells, but was similar at 22.2 compared with 12.2mmol/l glucose. Delta and other non-beta cells did not increase insulin secretion of contacting beta cells compared with that of single beta cells. Differences in insulin secretion between 22.2 and 12.2mmol/l glucose were observed in murine but not in human islets. Conclusions/interpretation: Human beta cells are highly heterogeneous in terms of insulin secretion so that a small fraction of beta cells contributes to the majority of insulin secreted. Homologous and heterologous intercellular contacts have a significant impact on insulin secretion and this could be related to the particular architecture of human islet

    Assessing the Device-performance Impacts of Structural Defects with TCAD Modeling

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    Advanced solar cell architectures like passivated emitter and rear (PERC) and heterojunction with intrinsic thin layer (HIT) are increasingly sensitive to bulk recombination. Present device models consider homogeneous bulk lifetime, which does not accurately reflect the effects of heterogeneously distributed defects. To determine the efficiency potential of multicrystalline silicon (mc-Si) in next-generation architectures, we present a higher-dimensional numerical simulation study of the impacts of structural defects on solar cell performance. We simulate these defects as an interfacial density of traps with a single mid-gap energy level using Shockley-Read-Hall (SRH) statistics. To account for enhanced recombination at the structural defects, we apply a linear scaling to the majority-carrier capture cross-section and scale the minority-carrier capture cross-section with the inverse of the line density of traps. At 300 K, our simulations of carrier occupation and recombination rate match literature electron-beam-induced current (EBIC) data and first-principles calculations of carrier capture, emission, and recombination for all the energy levels associated with dislocations decorated with metal impurities. We implement our model in Sentaurus Device, determining the losses across different device architectures for varying impurity decoration of grain boundaries.DoD/National Defense Science & Engineering Graduate Fellowship (NDSEG

    [O III]λ5007\lambda 5007 and X-ray Properties of a Complete Sample of Hard X-ray Selected AGNs in the Local Universe

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    We study the correlation between the [O III]λ5007\lambda 5007 and X-ray luminosities of local Active Galactic Nuclei (AGNs), using a complete, hard X-ray (>10>10 keV) selected sample in the Swift/BAT 9-month catalog. From our optical spectroscopic observations at the South African Astronomical Observatory and the literature, a catalog of [O III]λ5007\lambda 5007 line flux for all 103 AGNs at Galactic latitudes of b>15|b|>15^\circ is complied. Significant correlations with intrinsic X-ray luminosity (LXL_{\rm X}) are found both for observed (L[O III]L_{\rm [O~III]}) and extinction-corrected (L[O III]corL_{\rm [O~III]}^{\rm cor}) luminosities, separately for X-ray unabsorbed and absorbed AGNs. We obtain the regression form of L[O III]L_{\rm [O~III]} L210  keV1.18±0.07\propto L_{\rm 2-10\; keV}^{1.18\pm0.07} and L[O III]corL_{\rm [O~III]}^{\rm cor} L210  keV1.16±0.09\propto L_{\rm 2-10\; keV}^{1.16\pm0.09} from the whole sample. The absorbed AGNs with low (<<0.5\%) scattering fractions in soft X-rays show on average smaller L[O III]/LXL_{\rm [O~III]}/L_{\rm X} and L[O III]cor/LXL_{\rm [O~III]}^{\rm cor}/L_{\rm X} ratios than the other absorbed AGNs, while those in edge-on host galaxies do not. These results suggest that a significant fraction of this population are buried in tori with small opening angles. By using these L[O III]L_{\rm [O~III]} vs. LXL_{\rm X} correlations, the X-ray luminosity function of local AGNs (including Compton thick AGNs) in a standard population synthesis model gives much better agreement with the [O III]λ5007\lambda 5007 luminosity function derived from the Sloan Digital Sky Survey than previously reported. This confirms that hard X-ray observations are a very powerful tool to find AGNs with high completeness.Comment: 14 pages including 11 figures and 3 tables, accepted for publication in ApJ. In this manuscript, the observed 14-195 keV luminosities in Table 1 have been corrected to be exactly the same as in the original Swift/BAT 9-month catalog. Accordingly, Figures 2(a) and 3(a) and a part of Tables 2 and 3 have been updated. The changes from the previous version are small and do not affect the tex

    Psychotherapy for Personality Disorders in a Natural Setting: A Pilot Study over Two Years of Treatment.

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    Long-term assessment of the effects of psychotherapy for personality disorders (PDs) in a natural environment is an important task. Such research contributes to enlarge the practice-based evidence, embedded in broad collaborations between clinicians and researchers in psychotherapy for PDs. The present pilot study used rigorous assessment procedures and incorporated feedback loops of outcome information to the therapists in demonstrating the effects of psychotherapy for PD in a natural setting. The number of Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition (DSM-IV), criteria for any PD was the primary outcome (along with psychological distress, depression, impulsiveness, and quality of life as secondary measures), assessed at intake, 6, 12, 18, and 24 months of psychotherapy for N = 13 patients with PD. Data were analyzed using hierarchical linear modeling. Results demonstrated a large pre-post effect (d = 2.22) for the observer-rated measure (primary outcome), and small to medium effects for the secondary outcomes; these results were corroborated by a steady decrease of symptoms over all five time points, which was significant for several outcomes. These results add a piece to the literature by demonstrating the effects of long-term psychotherapy for PDs in increasingly diverse contexts and suggest that practice-oriented research can be carried out in a collaborative and systematic manner

    The bilateral deficit during jumping tasks: Relationship with speed and change of direction speed performance

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    Research to date has investigated the phenomenon of the bilateral deficit (BLD); however, limited research exists on its association with measures of athletic performance. The purpose of the present study was to investigate the magnitude of the BLD and examine its relationship with linear speed and change of direction speed (CODS) performance. Eighteen physically active and healthy university students performed double and single leg countermovement jumps (CMJ), drop jumps (DJ) and standing broad jumps (SBJ), to calculate the BLD across jump tasks. Subjects also performed 10m and 30m sprints and a 505 CODS test, which were correlated with all BLD metrics. Results showed varying levels of BLD across CMJ metrics (jump height, peak force, eccentric impulse, concentric impulse, peak power), DJ metrics (ground contact time, flight time), and the SBJ (distance). However, a bilateral facilitation (BLF) was shown for jump height and reactive strength index (RSI) during the DJ test. The main findings of the present study were that: 1) a larger BLD in CMJ jump height related to a faster 505 change of direction (COD) (left leg) (r = -0.48; p = 0.04), 505 COD (right leg) (r = -0.53; p = 0.02) and COD deficit (right leg) (r = -0.59; p = 0.01), 2) a larger BLD in CMJ concentric impulse related to faster 505 COD (left leg) (r = -0.51; p = 0.03), 505 COD (right leg) (r = -0.64, p = 0.01) and COD deficit (right leg) (r = -0.60; p = 0.01), 3) a larger BLD in DJ flight time related to a faster 505 COD (left leg) (r = -0.48; p = 0.04). These results suggest that a larger BLD is associated with faster CODS performance, but not linear speed. This highlights the individual nature of the BLD and may support the notion of developing movement competency on one limb for enhanced CODS performance

    Proliferation of sorted human and rat beta cells

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    Aims/hypothesis: The aim of the study was to determine whether purified beta cells can replicate in vitro and whether this is enhanced by extracellular matrix (ECM) and growth factors. Methods: Human beta cells were purified by FACS by virtue of their high zinc content using Newport Green, and excluding ductal and dead cells. Rat beta cells were sorted by autofluorescence or using the same method developed for human cells. Cells were plated on poly-l-lysine or ECMs from rat or human bladder carcinoma cells or bovine corneal ECM and incubated in the presence of BrdU with or without growth factors. Results: The newly developed method for sorting human beta cells yields a population containing 91.4 ± 2.8% insulin-positive cells with a low level of spontaneous apoptosis and a robust secretory response to glucose. Beta cells from 8-week-old rats proliferated in culture and this was increased by ECM. Among growth factors, only human growth hormone (hGH) and the glucagon-like peptide-1 analogue liraglutide enhanced proliferation of rat beta cells, with a significant increase on both poly-l-lysine and ECM. By contrast, sorted adult human beta cells from 16 donors aged 48.9 ± 14.3years (range 16-64years) failed to replicate demonstrably in vitro regardless of the substratum or growth factors used. Conclusions/interpretation: These findings indicate that, in our conditions, the fully differentiated human adult insulin-producing beta cell was unable to proliferate in vitro. This has important implications for any attempt to expand cells from pancreases of donors of this age group. By contrast, the rat beta cells used here were able to divide in vitro, and this was enhanced by ECM, hGH and liraglutid
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