1,241 research outputs found

    VideoCapsuleNet: A Simplified Network for Action Detection

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    The recent advances in Deep Convolutional Neural Networks (DCNNs) have shown extremely good results for video human action classification, however, action detection is still a challenging problem. The current action detection approaches follow a complex pipeline which involves multiple tasks such as tube proposals, optical flow, and tube classification. In this work, we present a more elegant solution for action detection based on the recently developed capsule network. We propose a 3D capsule network for videos, called VideoCapsuleNet: a unified network for action detection which can jointly perform pixel-wise action segmentation along with action classification. The proposed network is a generalization of capsule network from 2D to 3D, which takes a sequence of video frames as input. The 3D generalization drastically increases the number of capsules in the network, making capsule routing computationally expensive. We introduce capsule-pooling in the convolutional capsule layer to address this issue which makes the voting algorithm tractable. The routing-by-agreement in the network inherently models the action representations and various action characteristics are captured by the predicted capsules. This inspired us to utilize the capsules for action localization and the class-specific capsules predicted by the network are used to determine a pixel-wise localization of actions. The localization is further improved by parameterized skip connections with the convolutional capsule layers and the network is trained end-to-end with a classification as well as localization loss. The proposed network achieves sate-of-the-art performance on multiple action detection datasets including UCF-Sports, J-HMDB, and UCF-101 (24 classes) with an impressive ~20% improvement on UCF-101 and ~15% improvement on J-HMDB in terms of v-mAP scores

    Unsteady Model Estimation for Generic T-Tail Transport Aircraft Using Computational Data

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    Models including nonlinear and unsteady behaviors are developed for the longitudinal axis of the NASA Generic T-Tail Aircraft over a large range of angle of attack. These models are based on computational simulations of forced-oscillation tests in a wind tunnel. This work continues a recent study and an ongoing effort by NASA to improve aircraft simulations for pilot training in loss-of-control and stalled conditions. The objective of this work is to develop appropriate aerodynamic models that provide representative responses in simulation for a given class of aircraft. In the stall region, nonlinear unsteady responses are often present and may require an extended aerodynamic model compared to that used in the conventional flight envelope. In this study, two objectives are addressed. The first is to obtain representative models for the NASA Generic T-Tail aircraft over a wide range of angle of attack and the second is to continue development of a specialized CFD test technique that uses Schroeder sweeps to create information rich responses for unsteady aerodynamic model identification

    Efficient Unsteady Model Estimation Using Computational and Experimental Data

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    Improving aircraft simulations for pilot training in loss-of-control and stalled conditions is one goal of NASA research in the System Wide Safety Program. One part of this effort is to develop appropriate generic aerodynamic models that provide representative responses in simulation for a given class of aircraft. In this part of the flight envelope nonlinear unsteady responses are often present and may require an extended aerodynamic model compared to that used in the conventional flight envelope. In this preliminary study, two objectives are addressed. First, to obtain a representative model for a NASA generic aircraft at an unsteady condition in the flight envelope and second, to evaluate the techniques involved. To meet these objectives, two different generic aircraft configurations are modeled using both experimental and analytical data. With these results, an initial assessment of the efficiency and quality of the tools and test techniques are evaluated to develop guidance for analytical and experimental approaches to unsteady modeling

    Computational Study of a Generic T-tail Transport

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    This paper presents a computational study on the static and dynamic stability characteristics of a generic transport T-tail configuration under a NASA research program to improve stall models for civil transports. The NASA Tetrahedral Unstructured Software System (TetrUSS) was used to obtain both static and periodic dynamic solutions at low speed conditions for three Reynolds number conditions up to 60 deg angle of attack. The computational results are compared to experimental data. The dominant effects of Reynolds number for the static conditions were found to occur in the stall region. The pitch and roll damping coefficients compared well to experimental results up to up to 40 deg angle of attack whereas yaw damping coefficient agreed only up to 20 deg angle of attack

    Reduction of leukocyte microvascular adherence and preservation of blood-brain barrier function by superoxide-lowering therapies in a piglet model of neonatal asphyxia

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    Background: Asphyxia is the most common cause of brain damage in newborns. Substantial evidence indicates that leukocyte recruitment in the cerebral vasculature during asphyxia contributes to this damage. We tested the hypothesis that superoxide radical (O2â‹…_) promotes an acute post-asphyxial inflammatory response and blood-brain barrier (BBB) breakdown. We investigated the effects of removing O2â‹…_ by superoxide dismutase (SOD) or C3, the cell-permeable SOD mimetic, in protecting against asphyxia-related leukocyte recruitment. We also tested the hypothesis that xanthine oxidase activity is one source of this radical.Methods: Anesthetized piglets were tracheostomized, ventilated, and equipped with closed cranial windows for the assessment of post-asphyxial rhodamine 6G-labeled leukocyte-endothelial adherence and microvascular permeability to sodium fluorescein in cortical venules. Asphyxia was induced by discontinuing ventilation. SOD and C3 were administered by cortical superfusion. The xanthine oxidase inhibitor oxypurinol was administered intravenously.Results: Leukocyte-venular adherence significantly increased during the initial 2 h of post-asphyxial reperfusion. BBB permeability was also elevated relative to non-asphyxial controls. Inhibition of O2â‹…_ production by oxypurinol, or elimination of O2â‹…_ by SOD or C3, significantly reduced rhodamine 6G-labeled leukocyte-endothelial adherence and improved BBB integrity, as measured by sodium fluorescein leak from cerebral microvessels.Conclusion: Using three different strategies to either prevent formation or enhance elimination of O2â‹…_ during the post-asphyxial period, we saw both reduced leukocyte adherence and preserved BBB function with treatment. These findings suggest that agents which lower O2â‹…_ in brain may be attractive new therapeutic interventions for the protection of the neonatal brain following asphyxia

    LSF small molecule inhibitors phenocopy LSF-targeted siRNAs causing mitotic defects and senescence in cancer cells

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    The oncogene LSF has been proposed as a novel target with therapeutic potential for multiple cancers. LSF overexpression correlates with poor prognosis for both liver and colorectal cancers, for which there are currently limited therapeutic treatment options. In particular, molecularly targeted therapies for hepatocellular carcinoma targeting cellular receptors and kinases have yielded disappointing clinical results, providing an urgency for targeting distinct mechanisms. LSF small molecule inhibitors, Factor Quinolinone Inhibitors (FQIs), have exhibited robust anti-tumor activity in multiple pre-clinical models of hepatocellular carcinoma, with no observable toxicity. To understand how the inhibitors impact cancer cell proliferation, we characterized the cellular phenotypes that result from loss of LSF activity. Phenotypically, inhibition of LSF activity induced a mitotic delay with condensed, but unaligned, chromosomes. This mitotic disruption resulted in improper cellular division leading to multiple outcomes: multi-nucleation, apoptosis, and cellular senescence. The cellular phenotypes observed upon FQI1 treatment were due specifically to the loss of LSF activity, as siRNA specifically targeting LSF produced nearly identical phenotypes. Taken together, these findings confirm that LSF is a promising therapeutic target for cancer treatment.First author draf

    Tenofovir-Associated Nephrotoxicity in Two HIV-Infected Adolescent Males

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    We report two cases of tenofovir (TDF)-associated nephrotoxicity in perinatally HIV-infected adolescents. The first case, a 16-year-old African American male with an absolute CD4+ cell count of 314 cells/mm3, presented with an abrupt rise in serum creatinine leading to irreversible renal failure while on TDF-containing highly active antiretroviral therapy (HAART). While the patient had evidence of underlying kidney disease, the timing of his renal failure indicates that TDF played a central role. The second case, a 16-year-old African-American male with an absolute CD4+ cell count of 895 cells/mm3, presented with rickets and hypophosphatemia while receiving TDF-based HAART. To our knowledge, these cases represent the first reports of TDF-associated irreversible renal failure and rickets in pediatric patients. We believe these cases highlight important and potentially irreversible side effects of this agent and emphasize the need for further studies of the renal safety of TDF in pediatric patients

    A perfusion-capable microfluidic bioreactor for assessing microbial heterologous protein production

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    We present an integrated microfluidic bioreactor for fully continuous perfusion cultivation of suspended microbial cell cultures. This system allowed continuous and stable heterologous protein expression by sustaining the cultivation of Pichia pastoris over 11 days. This technical capability also allowed testing the impact of perfusion conditions on protein expression. This advance should enable small-scale models for process optimization in continuous biomanufacturing.United States. Defense Advanced Research Projects Agency (N66001-13-C-4025)National Cancer Institute (U.S.) (P30-CA14051)United States. National Institutes of Health (2T32GM008334-26
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