230 research outputs found

    The Selberg integral and Young books

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    The Selberg integral is an important integral first evaluated by Selberg in 1944. Stanley found a combinatorial interpretation of the Selberg integral in terms of permutations. In this paper, new combinatorial objects "Young books" are introduced and shown to have a connection with the Selberg integral. This connection gives an enumeration formula for Young books. It is shown that special cases of Young books become standard Young tableaux of various shapes: shifted staircases, squares, certain skew shapes, and certain truncated shapes. As a consequence, product formulas for the number of standard Young tableaux of these shapes are obtained.Comment: 13 pages, 11 figure

    Clinical and Radiographic Features of Adult-onset Ankylosing Spondylitis in Korean Patients: Comparisons between Males and Females

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    The objective of this study was to investigate clinical and radiographic features and gender differences in Korean patients with adult-onset ankylosing spondylitis. Multicenter cross-sectional studies were conducted in the rheumatology clinics of 13 Korean tertiary referral hospitals. All patients had a confirmed diagnosis of ankylosing spondylitis according to the modified New York criteria. Clinical, laboratory, and radiographic features were evaluated and disease activities were assessed using the Bath ankylosing spondylitis disease activity index. Five hundred and five patients were recruited. The male to female ratio was 6.1:1. Average age at symptom onset was 25.4±8.9 yr and average disease duration was 9.6±6.8 yr. Males manifested symptoms at a significantly earlier age. HLA-B27 was more frequently positive in males. Hips were more commonly affected in males, and knees in females. When spinal mobility was measured using tragus-to-wall distance and the modified Schober's test, females had significantly better results. Radiographic spinal changes, including bamboo spine and syndesmophytes, were more common in males after adjustment of confounding factors. In conclusion, we observed significant gender differences in radiographic spinal involvement as well as other clinical manifestations among Korea patients with adult-onset ankylosing spondylitis. These findings may influence the timing of the diagnosis and the choice of treatment

    Prediction of major depressive disorder following beta-blocker therapy in patients with cardiovascular diseases

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    Incident depression has been reported to be associated with poor prognosis in patients with cardiovascular disease (CVD), which might be associated with beta-blocker therapy. Because early detection and intervention can alleviate the severity of depression, we aimed to develop a machine learning (ML) model predicting the onset of major depressive disorder (MDD). A model based on L1 regularized logistic regression was trained against the South Korean nationwide administrative claims database to identify risk factors for the incident MDD after beta-blocker therapy in patients with CVD. We identified 50,397 patients initiating beta-blockers for CVD, with 774 patients developing MDD within 365 days after initiating beta-blocker therapy. An area under the receiver operating characteristic curve (AUC) of 0.74 was achieved. A history of non-selective beta-blockers and factors related to anxiety disorder, sleeping problems, and other chronic diseases were the most strong predictors. AUCs of 0.62–0.71 were achieved in the external validation conducted on six independent electronic health records and claims databases in the USA and South Korea. In conclusion, an ML model that identifies patients at high-risk for incident MDD was developed. Application of ML to identify susceptible patients for adverse events of treatment may serve as an important approach for personalized medicine

    Shank2 deletion in parvalbumin neurons leads to moderate hyperactivity, enhanced self-grooming and suppressed seizure susceptibility in mice

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    Shank2 is an abundant postsynaptic scaffolding protein implicated in neurodevelopmental and psychiatric disorders, including autism spectrum disorders (ASD). Deletion of Shank2 in mice has been shown to induce social deficits, repetitive behaviors, and hyperactivity, but the identity of the cell types that contribute to these phenotypes has remained unclear. Here, we report a conditional mouse line with a Shank2 deletion restricted to parvalbumin (PV)-positive neurons (Pv-Cre;Shank2fl/fl mice). These mice display moderate hyperactivity in both novel and familiar environments and enhanced self-grooming in novel, but not familiar, environments. In contrast, they showed normal levels of social interaction, anxiety-like behavior, and learning and memory. Basal brain rhythms in Pv-Cre;Shank2fl/fl mice, measured by electroencephalography, were normal, but susceptibility to pentylenetetrazole (PTZ)-induced seizures was decreased. These results suggest that Shank2 deletion in PV-positive neurons leads to hyperactivity, enhanced self-grooming and suppressed brain excitation. © 2018 Lee, Lee, Kim, Kim, Lee, Park, Yang, Kim and Ki

    Solution-Processed All-Solid-State Electrochromic Devices Based on SnO2/NiO doped with Tin

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    We investigated the photochromic (PC) and electrochromic (EC) properties of tin-doped nickel oxide (NiO) thin films for solution-processable all-solid-state EC devices. The PC effect is shown to be enhanced by the addition of Sn into the precursor NiO solution. We fabricated an EC device with six layers—ITO/TiO2 (counter electrode)/SnO2 (ion-conducting layer)/SiO2 (barrier)/NiO doped with tin (EC layer)/ITO—by a hybrid fabrication process (sputtering for ITO and TiO2, sol–gel spin coating for SnO2 and NiO). The EC effect was also observed to be improved with the Sn-doped NiO layer. It was demonstrated that UV/O3 treatment is one of the critical processes that determine the EC performance of the hydroxide ion-based device. UV/O3 treatment generates hydroxide ions, induces phase separation from a single mixture of SnO2 and silicone oil, and improves the surface morphology of the films, thereby boosting the performance of EC devices. EC performance can be enhanced further by optimizing the thickness of TiO2 and SiO2 layers. Specifically, the SiO2 barrier blocks the transport of charges, bringing in an increase in anodic coloration. We achieved the transmittance modulation of 38.3% and the coloration efficiency of 39.7 cm2/C. We also evaluated the heat resistance of the all-solid-state EC device and found that the transmittance modulation was decreased by 36% from its initial value at 100 °C. Furthermore, we demonstrated that a large-area EC device can be fabricated using slot-die coating without much compromise on EC performance

    Development of Sustainable Technology to Mitigate VOCs Pollution from Air Using a Continuous System Composed of Fe-ZSM-5 Coated on Polypropylene Tubes Coupled with UV Irradiation at the Pilot Scale

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    In this work, the efficacy of volatile organic compounds (VOCs), such as benzene, toluene, ethylbenzene, and xylene, for the removal of indoor air in a heterogeneous photo-Fenton catalytic semi pilot reactor was investigated at room temperature. Fe-zeolite socony mobil (ZSM)-5 was used as the adsorptive catalytic material, which was coated on the polyethylene tubes as a solid support. The response of Fe-ZSM-5 to UV dry irradiation was investigated in terms of VOC degradation from the indoor air. Different coating materials were tested in order to achieve better binding and less pore blockage. Scanning electron microscope (SEM) micrographs of the Fe-ZSM-5 coated tubes were used for the morphological analysis of the tubes. A complete modular semi pilot reactor (12.51 L) was designed to accommodate the Fe-ZSM-5 coated tubes and UV lamps for UV irradiation, in order to achieve the degradation for VOC and the regeneration of the catalytic material. After completion of the setup, the plant design parameters, such as the linear velocity, surface volume loading rate (SVL), and space retention time (SRT), were calculated

    Enhanced Microwave Heating Uniformity using Reconfigurable Fresnel Zone Plate

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    Microwave heating is adapted in diverse industrial applications, but achieving heating uniformity remains elusive. Conventional microwave heating methods are problematic in terms of accurate analysis and the design process is heavily dependent on trial and errors. In this paper, we propose a method of beam steering using a 2.45 GHz reconfigurable Fresnel zone plate antenna. The devised topology is placed inside a chamber with an absorber. Studies indicate that the uniformity of the electric field increases by more than three times, underlining the fact that microwave heating uniformity can be significantly enhanced using the proposed method.1

    NGL-3 in the regulation of brain development, Akt/GSK3b signaling, long-term depression, and locomotive and cognitive behaviors

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    Netrin-G ligand-3 (NGL-3) is a postsynaptic adhesion molecule known to directly interact with the excitatory postsynaptic scaffolding protein postsynaptic density-95 (PSD-95) and trans-synaptically with leukocyte common antigen-related (LAR) family receptor tyrosine phosphatases to regulate presynaptic differentiation. Although NGL-3 has been implicated in the regulation of excitatory synapse development by in vitro studies, whether it regulates synapse development or function, or any other features of brain development and function, is not known. Here, we report that mice lacking NGL-3 (Ngl3-/- mice) show markedly suppressed normal brain development and postnatal survival and growth. A change of the genetic background of mice from pure to hybrid minimized these developmental effects but modestly suppressed N-methyl-D-aspartate (NMDA) receptor (NMDAR)-mediated synaptic transmission in the hippocampus without affecting synapse development, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor (AMPAR)-mediated basal transmission, and presynaptic release. Intriguingly, long-term depression (LTD) was near-completely abolished in Ngl3-/- mice, and the Akt/glycogen synthase kinase 3β (GSK3β) signaling pathway, known to suppress LTD, was abnormally enhanced. In addition, pharmacological inhibition of Akt, but not activation of NMDARs, normalized the suppressed LTD in Ngl3-/- mice, suggesting that Akt hyperactivity suppresses LTD. Ngl3-/- mice displayed several behavioral abnormalities, including hyperactivity, anxiolytic-like behavior, impaired spatial memory, and enhanced seizure susceptibility. Among them, the hyperactivity was rapidly improved by pharmacological NMDAR activation. These results suggest that NGL-3 regulates brain development, Akt/GSK3β signaling, LTD, and locomotive and cognitive behaviors. © 2019 Lee et al

    Sustainable Removal of BTEX Gas Using Regenerated Metal Containing SiO2

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    In the last decades, the removal of benzene, toluene, ethylbenzene, and xylene (BTEX) has been considered a major environmental crisis. In this study, two novel nanocomposite materials (Fe2O3/SiO2 and Fe2O3-Mn2O3/SiO2) that have regeneration ability by UV irradiation have been fabricated to remove BTEX at ambient temperature. This research revealed that both nanocomposites could remove more than 85% of the BTEX in the first cycle. The adsorption capacities followed the order of ethylbenzene > m-xylene > toluene > benzene as in the molecular weight order. The reusability test using UV irradiation showed that the performance of Fe2O3/SiO2 decreased drastically after the fifth cycle for benzene. On the other hand, when Mn is located in the nanocomposite structure, Fe2O3-Mn2O3/SiO2 could maintain its adsorption performance with more than 80% removal efficiency for all the BTEX for ten consecutive cycles. The difference in the reusability of the two nanocomposites is that the electron energy (from the valence band to the conduction band) for BTEX decomposition is changed due to the presence of manganese. This study provides a promising approach for designing an economical reusable nanomaterial, which can be used for VOC-contaminated indoor air

    Scattering Mitigation Frequency Selective Surface for Unidirectional Blockage Compensation

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    This paper describes a concept of scattering mitigation frequency selective surface (FSS) for unidirectional blockage compensation using a single substrate frequency selective surface without modification of the obstacle. The devised scattering mitigation FSS generates complementary electric field to that of the blockage, enabling the blockage to become electromagnetically-transparent to the antenna. Using superposition and linearity, the spatial impedance distribution of the FSS is calculated. The devised FSS consists of indented patch elements consisting of four symmetric via structures to exhibit wide tunable transmission phase range and less than 1-dB insertion loss at the center frequency of 30.0 GHz for proof-of-concept. The proposed scattering mitigation FSS is verified in TMz- and TEz-polarized cylinder scattering scenario. Measurement confirm the improvements of the main beam peak gain and restoration of far-field radiation patterns. The proposed investigation is expected to provide concise and practical scattering reduction solutions for blockage scenario such as vehicular communication in urban areas.11Nsciescopu
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