2,675 research outputs found

    Automating Carotid Intima-Media Thickness Video Interpretation with Convolutional Neural Networks

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    Cardiovascular disease (CVD) is the leading cause of mortality yet largely preventable, but the key to prevention is to identify at-risk individuals before adverse events. For predicting individual CVD risk, carotid intima-media thickness (CIMT), a noninvasive ultrasound method, has proven to be valuable, offering several advantages over CT coronary artery calcium score. However, each CIMT examination includes several ultrasound videos, and interpreting each of these CIMT videos involves three operations: (1) select three end-diastolic ultrasound frames (EUF) in the video, (2) localize a region of interest (ROI) in each selected frame, and (3) trace the lumen-intima interface and the media-adventitia interface in each ROI to measure CIMT. These operations are tedious, laborious, and time consuming, a serious limitation that hinders the widespread utilization of CIMT in clinical practice. To overcome this limitation, this paper presents a new system to automate CIMT video interpretation. Our extensive experiments demonstrate that the suggested system significantly outperforms the state-of-the-art methods. The superior performance is attributable to our unified framework based on convolutional neural networks (CNNs) coupled with our informative image representation and effective post-processing of the CNN outputs, which are uniquely designed for each of the above three operations.Comment: J. Y. Shin, N. Tajbakhsh, R. T. Hurst, C. B. Kendall, and J. Liang. Automating carotid intima-media thickness video interpretation with convolutional neural networks. CVPR 2016, pp 2526-2535; N. Tajbakhsh, J. Y. Shin, R. T. Hurst, C. B. Kendall, and J. Liang. Automatic interpretation of CIMT videos using convolutional neural networks. Deep Learning for Medical Image Analysis, Academic Press, 201

    Numerical Simulation on Tunnel Splitting of Bose-Einstein Condensate in Multi-Well Potentials

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    The low-energy-level macroscopic wave functions of the Bose-Einstein condensate(BEC) trapped in a symmetric double-well and a periodic potential are obtained by solving the Gross-Pitaevskii equation numerically. The ground state tunnel splitting is evaluated in terms of the even and odd wave functions corresponding to the global ground and excited states respectively. We show that the numerical result is in good agreement with the analytic level splitting obtained by means of the periodic instanton method.Comment: 22 pages,7 figure

    Protective Effect of (-)-Epigallocatechin Gallate against Photo-Damage Induced by Ultraviolet A in Human Skin Fibroblasts

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    Purpose: To investigate the photoprotective effect of (-)-epigallocatechin gallate (EGCG), one of tea catechins, on human skin fibroblast (HSF) irradiated by ultraviolet A.Methods: HSF cells were incubated in serum-free Dulbecco's Modified Eagle's Medium (DMEM) with or without EGCG for 2 h, and then irradiated by UV A. Blank (control) was incubated in DMEM without EGCG and UV A-irradiation. Cell viability was determined by 3-(4, 5-dimethylthiazol-2-yl)-2, 5- diphenyltetrazolium bromide (MTT) method. Protein concentration of the samples was determined using a PA102 Bradford protein assay kit. Malondialdehyde (MDA), glutathione peroxidase (GSH-Px) and superoxide anion radicals were determined using MDA assay kit, GSH-Px assay kit and superoxide anion radical assay kit, respectively.Results: HSF viability decreased with dosage of UV A irradiation with 50 % lethal dose (LD50)of 9 J/cm2. Pre-incubation of HSF in 10 μg/mL EGCG aqueous solution for 2 h before exposure to UV A alleviated the suppressive effect of UV A on HSF. Compared to UVA irradiation alone, HSF viability and GSH-Px activity in the EGCG pretreatment increased by 18.3 and 103.4 %, accompanying decrease in level of superoxide anion radicals and MDA by 44.6 and 16.6 %, respectively.Conclusion: EGCG alleviates UV A-induced HSF photo-damage through relieving oxidative stress by increasing activity of GSH-Px and scavenging capacity of superoxide anion radical.Keywords: Irradiation, Catechins, Photoaging, Photoprotection, Malondialdehyde, Glutathione peroxidase, Superoxide anion radica

    Low-Energy Charge-Density Excitations in MgB2_{2}: Striking Interplay between Single-Particle and Collective Behavior for Large Momenta

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    A sharp feature in the charge-density excitation spectra of single-crystal MgB2_{2}, displaying a remarkable cosine-like, periodic energy dispersion with momentum transfer (qq) along the cc^{*}-axis, has been observed for the first time by high-resolution non-resonant inelastic x-ray scattering (NIXS). Time-dependent density-functional theory calculations show that the physics underlying the NIXS data is strong coupling between single-particle and collective degrees of freedom, mediated by large crystal local-field effects. As a result, the small-qq collective mode residing in the single-particle excitation gap of the B π\pi bands reappears periodically in higher Brillouin zones. The NIXS data thus embody a novel signature of the layered electronic structure of MgB2_{2}.Comment: 5 pages, 4 figures, submitted to PR

    Robust Digital Holography For Ultracold Atom Trapping

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    We have formulated and experimentally demonstrated an improved algorithm for design of arbitrary two-dimensional holographic traps for ultracold atoms. Our method builds on the best previously available algorithm, MRAF, and improves on it in two ways. First, it allows for creation of holographic atom traps with a well defined background potential. Second, we experimentally show that for creating trapping potentials free of fringing artifacts it is important to go beyond the Fourier approximation in modelling light propagation. To this end, we incorporate full Helmholtz propagation into our calculations.Comment: 7 pages, 4 figure

    CDK-dependent nuclear localization of B-Cyclin Clb1 promotes FEAR activation during meiosis I in budding yeast

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    Cyclin-dependent kinases (CDK) are master regulators of the cell cycle in eukaryotes. CDK activity is regulated by the presence, post-translational modification and spatial localization of its regulatory subunit cyclin. In budding yeast, the B-cyclin Clb1 is phosphorylated and localizes to the nucleus during meiosis I. However the functional significance of Clb1's phosphorylation and nuclear localization and their mutual dependency is unknown. In this paper, we demonstrate that meiosis-specific phosphorylation of Clb1 requires its import to the nucleus but not vice versa. While Clb1 phosphorylation is dependent on activity of both CDK and polo-like kinase Cdc5, its nuclear localization requires CDK but not Cdc5 activity. Furthermore we show that increased nuclear localization of Clb1 during meiosis enhances activation of FEAR (Cdc Fourteen Early Anaphase Release) pathway. We discuss the significance of our results in relation to regulation of exit from meiosis I

    High-Throughput Precision Phenotyping of Left Ventricular Hypertrophy with Cardiovascular Deep Learning

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    Left ventricular hypertrophy (LVH) results from chronic remodeling caused by a broad range of systemic and cardiovascular disease including hypertension, aortic stenosis, hypertrophic cardiomyopathy, and cardiac amyloidosis. Early detection and characterization of LVH can significantly impact patient care but is limited by under-recognition of hypertrophy, measurement error and variability, and difficulty differentiating etiologies of LVH. To overcome this challenge, we present EchoNet-LVH - a deep learning workflow that automatically quantifies ventricular hypertrophy with precision equal to human experts and predicts etiology of LVH. Trained on 28,201 echocardiogram videos, our model accurately measures intraventricular wall thickness (mean absolute error [MAE] 1.4mm, 95% CI 1.2-1.5mm), left ventricular diameter (MAE 2.4mm, 95% CI 2.2-2.6mm), and posterior wall thickness (MAE 1.2mm, 95% CI 1.1-1.3mm) and classifies cardiac amyloidosis (area under the curve of 0.83) and hypertrophic cardiomyopathy (AUC 0.98) from other etiologies of LVH. In external datasets from independent domestic and international healthcare systems, EchoNet-LVH accurately quantified ventricular parameters (R2 of 0.96 and 0.90 respectively) and detected cardiac amyloidosis (AUC 0.79) and hypertrophic cardiomyopathy (AUC 0.89) on the domestic external validation site. Leveraging measurements across multiple heart beats, our model can more accurately identify subtle changes in LV geometry and its causal etiologies. Compared to human experts, EchoNet-LVH is fully automated, allowing for reproducible, precise measurements, and lays the foundation for precision diagnosis of cardiac hypertrophy. As a resource to promote further innovation, we also make publicly available a large dataset of 23,212 annotated echocardiogram videos

    Journey with Ting-Peng Liang in Pacific Asia Information Systems Field

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    Our respectful old friend Professor Ting-Peng Liang (in short, TP) whom we loved suddenly passed away on May 20, 2021. But we cannot forget his smile and passion, and his inerasable footprints in PACIS, PAJAIS, and AIS Community. He was the founder of PACIS, founding editor-in-chief of PAJAIS, and past president of AIS to list just a few. He was the pioneer who received the first AIS Fellow and the first LEO Award from Asia Pacific. That is why the leaders of the information systems field organized the first ever special tribute session in PACIS 2021 in memory of TP (https://aisel.aisnet.org/pacis2021/253/
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