36,975 research outputs found

    Deformations of thick two-material cylinder under axially varying radial pressure

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    Stresses and deformations in thick, short, composite cylinder subjected to axially varying radial pressure are studied. Effect of slippage at the interface is examined. In the NASTRAN finite element model, multipoint constraint feature is utilized. Results are compared with theoretical analysis and SAP-IV computer code. Results from NASTRAN computer code are in good agreement with the analytical solutions. Results suggest a considerable influence of interfacial slippage on the axial bending stresses in the cylinder

    Ureteric injuries following laparoscopic hysterectomy: A report of three cases

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    The laparoscopic approach to uterine disorders requires greater skills and expertise but may be associated with longer operating times, and complications when compared to the abdominal approaches. Of the potential complications during laparoscopic hysterectomies, ureteric injures are of a major concern. We report on three ureteric injuries encountered during total laparoscopic hysterectomy and review the relevant literature

    Colchicine therapy in acute coronary syndrome patients acts on caspase-1 to suppress NLRP3 inflammasome monocyte activation

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    Inflammasome activation, with subsequent release of pro-inflammatory cytokines interleukin-1β (IL-1β) and IL-18, has recently been implicated in atherosclerosis-associated inflammation. This study aims to assess in acute coronary syndrome (ACS) patients (1) inflammasome activation in circulating monocytes and (2) whether short-term oral colchicine, a recognized anti-inflammatory agent that has been shown to be cardio-protective in clinical studies, might acutely suppress inflammasome-dependent inflammation. ACS patients (n=21) were randomized to oral colchicine (1 mg followed by 0.5 mg 1 h later) or no treatment, and compared with untreated healthy controls (n=9). Peripheral venous blood was sampled pre- (day 1) and 24 h post- (day 2) treatment. Monocytes were cultured and stimulated with ATP. Analysis of key inflammasome markers was performed by ELISA. IL-1β secretion increased by 580.4% (P<0.01) in ACS patients compared with controls but only with ATP stimulation. Untreated ACS patients secreted significantly higher levels of IL-18 compared with healthy controls independent of ATP stimulation (P<0.05). Colchicine treatment in ACS patients markedly reduced intracellular and secreted levels of IL-1β compared with pre-treatment levels (P<0.05 for both), as well as significantly reducing pro-caspase-1 mRNA levels by 57.7% and secreted caspase-1 protein levels by 30.2% compared with untreated patients (P<0.05 for both). Monocytes from ACS patients are ‘primed’ to secrete inflammasome-related cytokines and short-term colchicine acutely and markedly suppresses monocyte caspase-1 activity, thereby reducing monocyte secretion of IL-1β

    MOON: A Mixed Objective Optimization Network for the Recognition of Facial Attributes

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    Attribute recognition, particularly facial, extracts many labels for each image. While some multi-task vision problems can be decomposed into separate tasks and stages, e.g., training independent models for each task, for a growing set of problems joint optimization across all tasks has been shown to improve performance. We show that for deep convolutional neural network (DCNN) facial attribute extraction, multi-task optimization is better. Unfortunately, it can be difficult to apply joint optimization to DCNNs when training data is imbalanced, and re-balancing multi-label data directly is structurally infeasible, since adding/removing data to balance one label will change the sampling of the other labels. This paper addresses the multi-label imbalance problem by introducing a novel mixed objective optimization network (MOON) with a loss function that mixes multiple task objectives with domain adaptive re-weighting of propagated loss. Experiments demonstrate that not only does MOON advance the state of the art in facial attribute recognition, but it also outperforms independently trained DCNNs using the same data. When using facial attributes for the LFW face recognition task, we show that our balanced (domain adapted) network outperforms the unbalanced trained network.Comment: Post-print of manuscript accepted to the European Conference on Computer Vision (ECCV) 2016 http://link.springer.com/chapter/10.1007%2F978-3-319-46454-1_

    Synthesis and Cell Adhesive Properties of Linear and Cyclic RGD Functionalized Polynorbornene Thin Films

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    Described herein is the efficient synthesis and evaluation of bioactive arginine-glycine-aspartic acid (RGD) functionalized polynorbornene-based materials for cell adhesion and spreading. Polynorbornenes containing either linear or cyclic RGD peptides were synthesized by ring-opening metathesis polymerization (ROMP) using the well-defined ruthenium initiator [(H_(2)IMes)(pyr)_(2)(Cl)_(2)Ru═CHPh]. The random copolymerization of three separate norbornene monomers allowed for the incorporation of water-soluble polyethylene glycol (PEG) moieties, RGD cell recognition motifs, and primary amines for postpolymerization cross-linking. Following polymer synthesis, thin-film hydrogels were formed by cross-linking with bis(sulfosuccinimidyl) suberate (BS^3), and the ability of these materials to support human umbilical vein endothelial cell (HUVEC) adhesion and spreading was evaluated and quantified. When compared to control polymers containing either no peptide or a scrambled RDG peptide, polymers with linear or cyclic RGD at varying concentrations displayed excellent cell adhesive properties in both serum-supplemented and serum-free media. Polymers with cyclic RGD side chains maintained cell adhesion and exhibited comparable integrin binding at a 100-fold lower concentration than those carrying linear RGD peptides. The precise control of monomer incorporation enabled by ROMP allows for quantification of the impact of RGD structure and concentration on cell adhesion and spreading. The results presented here will serve to guide future efforts for the design of RGD functionalized materials with applications in surgery, tissue engineering, and regenerative medicine

    Numerical Investigation of Second Mode Attenuation over Carbon/Carbon Surfaces on a Sharp Slender Cone

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    We have carried out axisymmetric numerical simulations of a spatially developing hypersonic boundary layer over a sharp 7^{\circ{}}-half-angle cone at M=7.5M_\infty=7.5 inspired by the experimental investigations by Wagner (2015). Simulations are first performed with impermeable (or solid) walls with a one-time broadband pulse excitation applied upstream to determine the most convectively-amplified frequencies resulting in the range 260kHz -- 400kHz, consistent with experimental observations of second-mode instability waves. Subsequently, we introduce harmonic disturbances via continuous periodic suction and blowing at 270kHz and 350kHz. For each of these forcing frequencies complex impedance boundary conditions (IBC), modeling the acoustic response of two different carbon/carbon (C/C) ultrasonically absorptive porous surfaces, are applied at the wall. The IBCs are derived as an output of a pore-scale aeroacoustic analysis -- the inverse Helmholtz Solver (iHS) -- which is able to return the broadband real and imaginary components of the surface-averaged impedance. The introduction of the IBCs in all cases leads to a significant attenuation of the harmonically-forced second-mode wave. In particular, we observe a higher attenuation rate of the introduced waves with frequency of 350kHz in comparison with 270kHz, and, along with the iHS impedance results, we establish that the C/C surfaces absorb acoustic energy more effectively at higher frequencies.Comment: AIAA-SciTech 201

    Transmission through a n interacting quantum dot in the Coulomb blockade regime

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    The influence of electron-electron (e-e) interactions on the transmission through a quantum dot is investigated numerically for the Coulomb blockade regime. For vanishing magnetic fields, the conductance peak height statistics is found to be independent of the interactions strength. It is identical to the statistics predicted by constant interaction single electron random matrix theory and agrees well with recent experiments. However, in contrast to these random matrix theories, our calculations reproduces the reduced sensitivity to magnetic flux observed in many experiments. The relevant physics is traced to the short range Coulomb correlations providing thus a unified explanation for the transmission statistics as well as for the large conductance peak spacing fluctuations observed in other experiments.Comment: Final version as publishe

    Cyclic AMP-associated shape change in mesangial cells and its reversal by prostaglandin E2

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    Cyclic AMP-associated shape change in mesangial cells and its reversal by prostaglandin E2. The mesangial cell is a glomerular cell type with smooth muscle-like (contractile) properties. The responses evoked in cultured mesangial cells by catecholamines were examined in the presence or absence of prostaglandin E2 (PGE2) with or without a phosphodiesterase inhibitor. Exposure to 10-4M norepinephrine, epinephrine, or isoproterenol elevated intracellular cyclic AMP (cAMP) levels in mesangial cells (25th to 30th passages) nearly threefold. If isobutylmethylxanthine (MIX) was also included, the hormones caused marked further increases in cAMP (after a 20-min incubation, control with MIX, 64.2 ± 5.2 pmoles/mg protein; 10-4M norepinephrine, 4266 ± 284 pmoles/mg protein; 10-4M epinephrine, 5812 ± 173 pmoles/mg protein; and 10-4M isoproterenol, 3136 ± 114 pmoles/mg protein). Under both of these circumstances (that is, catecholamines with or without MIX) greater than 50% of the cells underwent a change in shape (that is, had a round cell body with long, thin tapered processes). The cAMP and shape change response was independent of extracellular calcium ions and appeared to be due to β-adrenergic stimulation. Isoproterenol with MIX stimulated an alteration in morphology and cAMP production at concentrations of 10-4M to 10-9M. Within 10 min following β-adrenergic stimulation (10-4M isoproterenol plus MIX) cAMP was maximum; at this time a shape change was first evident. Eighty-five to one hundred percent of the cells had undergone a shape change by 40 min. Dibutyryl cAMP (10-3M) also induced a shape change in cultured mesangial cells. The addition of PGE2 to either morphologically altered cells or to the isoproterenol incubation medium (with or without MIX) prior to treating the cells, resulted in complete restoration to the normal flat appearance of mesangial cells or no shape change, respectively. PGE2 attenuated but did not abolish hormone-induced elevations in intracellular cAMP. Thus, catecholamines caused mesangial cells to change their shape in association with elevations of intracellular cAMP. PGE2 markedly inhibited the shape change as well as markedly attenuated cAMP generation.La modification de la forme associé l'PAMP cyclique dans les cellules mésangiales et sa interversion par prostaglandine E2. La cellule mésangiale est un type cellulaire glomérulaire ayant despropriétés voisines du muscle lisse (contractile). Les réponses évoquées dans des cellules mésangiales en culture par les catécholamines ont été examinées en présence ou en l'absence de prostaglandine E2 (PGE2) avec ou sans un inhibiteur des phosphodiestérases. L'exposition à 10-4M de noradrénaline, d'adrénaline, ou d'isoprotérénol a élevé les niveaux d'AMP cyclique intracellulaires (cAMP) dans les cellules mésangiales (25ème à 30ème passages) de presque troisfois. Si de l'isobutylméthylxanthine (MIX) était également inclue, les hormones entraînaient des augmentations plus fortes de cAMP (après 20 min d'incubation, contrôles avec MIX, 64,2 ± 5,2 pmoles/mg protéines; 10-4M noradrénaline, 4266 ± 284 pmoles/g protéines; 10-4M adrénaline, 5812 ± 173 pmoles/mg protéines; et 10-4M isoprotérénol, 3136 ± 114 pmoles/mg protéines). Dans chacune de ces circontances (c'est-à-dire catécholamines avec ou sans MIX), plus de 50% cellules subissaient une modification de forme (c'est-à-dire avaient un corps cellulaire rond, avec des expansions rubannées longues et fines). Les réponses cAMP et de modification de forme étaient indépendantes des ions calcium extracellulaires, et paraîssaient être dues à la stimulation β-adrénergique. L'isoprotérénol avec MIX stimulait une altération de la morphologie et de la production de cAMP pour des concentrations de 10-4M à 10-9M. En 10 min, après stimulation β-adrénergique (10-4M d'isoprotérénol plus MIX), cAMP était maximum; à ce moment, la modification de forme était évidente. Quatre-vingt-cinq à cent pour cent des cellules avaient subi une modification de forme en 40 min. Le dibutyryl cAMP (10-3M) induisait également une modification de forme dans les cellules mésangiales en culture. L'addition de PGE2 soit à des cellules morphologiquement altérées, soit au milieu d'incubation de l'isoprotérénol (avec ou sans MIX), avant de traiter les cellules, entraînait une restauration complète de l'apparence normale, plate, des cellules mésangiales, ou l'absence de modification, respectivement. PGE2 a atténué, mais n'a pas aboli les élévations induites par les hormones du cAMP intracellulaire. Ainsi, les catécholamines faisaient changer de forme les cellules mésangiales en association avec des élévations du cAMP intracellulaire. La PGE2 inhibait de façon marquée la modification de changement, et atténuait sensiblement la génération de cAMP

    Finite temperature effects in Coulomb blockade quantum dots and signatures of spectral scrambling

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    The conductance in Coulomb blockade quantum dots exhibits sharp peaks whose spacings fluctuate with the number of electrons. We derive the temperature-dependence of these fluctuations in the statistical regime and compare with recent experimental results. The scrambling due to Coulomb interactions of the single-particle spectrum with the addition of an electron to the dot is shown to affect the temperature-dependence of the peak spacing fluctuations. Spectral scrambling also leads to saturation in the temperature dependence of the peak-to-peak correlator, in agreement with recent experimental results. The signatures of scrambling are derived using discrete Gaussian processes, which generalize the Gaussian ensembles of random matrices to systems that depend on a discrete parameter -- in this case, the number of electrons in the dot.Comment: 14 pages, 4 eps figures included, RevTe
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