359 research outputs found

    Iterative detection for frequency-asynchronous distributed Alamouti-coded (FADAC) OFDM

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    We propose a near intercarrier interference (ICI)-free and very low complexity iterative detector for frequency-asynchronous distributed Alamouti-coded (FADAC) orthogonal frequency division multiplexing (OFDM). In the previous cancelation schemes, the entire subcarrier signals from one transmit (TX) antenna are estimated and canceled in the received signal from the other TX antenna and vice versa. However, the reliability of the estimated symbols are revealed to significantly vary across the subcarriers and thus, the poorly estimated symbols lead to the incorrect cancelation. Motivated from this, we first propose a scheme which does not cancel the interfering subcarrier(s) at the half band edges which undergo very high interference in FADAC-OFDM. For further improvement, we propose a so-called selective scheme which instantly measures the reliability of the detected symbols at each iteration and then exclude the unreliable symbols in the estimated interference generation. Moreover, the proposed scheme has a drastically reduced complexity by converting the cancelation process from the subcarrier domain to the time domain. In accordance with the analysis on the considered reliability measures, the numerical results show that the proposed scheme achieves the near ICI-free level only within three or four iterations for wide ranges of SNR, frequency offset, and delay spread.1

    Vitamin D serum levels in children with allergic and vasomotor rhinitis

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    PurposeIn addition to regulating calcium and phosphorus homeostasis and bone metabolism, vitamin D is known as an immune modulator. Recently, there has been increased worldwide interest in the association between low levels of vitamin D and allergic diseases. The purpose of this study was to assess the relationship between serum vitamin D levels and allergic/vasomotor rhinitis (AR/VR) in children.MethodsThis study included 164 patients. The sample included 59 patients with AR, 42 patients with VR, and 63 controls. Their ages ranged from 0 to 16 years. We examined the levels of 25-hydroxyvitamin D, Immunoglobulin E, specific IgE, and eosinophil cationic protein; peripheral blood eosinophil count; and the results of a skin prick test.ResultsSerum 25-hydroxyvitamin D levels were 19.0±8.5 ng/mL in the AR group, 25.5±10.9 ng/mL in the VR group, and 26.9±10.7 ng/mL in the control group. After adjustment for body mass index and season at the time of blood sampling, vitamin D levels in the AR group were lower than those of the VR group (P=0.003) and control group (P<0.001). Vitamin D levels were inversely correlated with Immunoglobulin E levels (r=-0.317, P<0.001). AR patients with food allergy or atopic dermatitis did not have lower levels of 25-hydroxyvitamin D than AR patients without these diseases.ConclusionThis study demonstrates a possible relationship between vitamin D levels and allergic rhinitis in Korean children

    Successful treatment with vedolizumab in an adolescent with Crohn disease who had developed active pulmonary tuberculosis while receiving infliximab

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    Vedolizumab (VDZ) has been approved for the treatment of inflammatory bowel diseases (IBDs) in patients aged ≥18 years. We report a case of a pediatric patient with Crohn disease (CD) who was successfully treated with VDZ. A 16-year-old female developed severe active pulmonary tuberculosis (TB) during treatment with infliximab (IFX). IFX was stopped, and TB treatment was started. After a 6-month regimen of standard TB medication, her pulmonary TB was cured; however, gastrointestinal symptoms developed. Due to the concern of the patient and parents regarding TB reactivation on restarting treatment with IFX, VDZ was started off-label. After the second dose of VDZ, the patient was in clinical remission and her remission was continuously sustained. Ileocolonoscopy at 1-year after VDZ initiation revealed endoscopic healing. Therapeutic drug monitoring conducted during VDZ treatment showed negative antibodies to VDZ. No serious adverse events occurred during the VDZ treatment. This is the first case report in Korea demonstrating the safe and effective use of VDZ treatment in a pediatric CD patient. In cases that require recommencement of treatment with biologics after recovery of active pulmonary TB caused by anti-tumor necrosis factor agents, VDZ may be a good option even in pediatric IBD

    High-efficiency Bidirectional Buck-Boost Converter for Residential Energy Storage System

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    This paper proposes a bidirectional dc-dc converter for residential micro-grid applications. The proposed converter can operate over an input voltage range that overlaps the output voltage range. This converter uses two snubber capacitors to reduce the switch turn-off losses, a dc-blocking capacitor to reduce the input/output filter size, and a 1:1 transformer to reduce core loss. The windings of the transformer are connected in parallel and in reverse-coupled configuration to suppress magnetic flux swing in the core. Zero-voltage turn-on of the switch is achieved by operating the converter in discontinuous conduction mode. The experimental converter was designed to operate at a switching frequency of 40-210 kHz, an input voltage of 48 V, an output voltage of 36-60 V, and an output power of 50-500 W. The power conversion efficiency for boost conversion to 60 V was >= 98.3% in the entire power range. The efficiency for buck conversion to 36 V was >= 98.4% in the entire power range. The output voltage ripple at full load was <3.59 V-p.p for boost conversion (60 V) and 1.35 V-p.p for buck conversion (36 V) with the reduced input/output filter. The experimental results indicate that the proposed converter is well-suited to smart-grid energy storage systems that require high efficiency, small size, and overlapping input and output voltage ranges.11Ysciescopu

    A Very Low Complexity QRD-M MIMO Detection Based on Adaptive Search Area

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    We propose a low complexity QR decomposition (QRD)-M multiple input multiple output (MIMO) detection algorithm based on adaptive search area. Unlike the conventional QRD-M MIMO detection algorithm, which determines the next survivor path candidates after searching over the entire constellation points at each detection layer, the proposed algorithm adaptively restricts the search area to the minimal neighboring constellation points of the estimated QRD symbol according to the instantaneous channel condition at each layer. First, we set up an adaptation rule for search area using two observations that inherently reflect the instantaneous channel condition, that is, the diagonal terms of the channel upper triangle matrix after QR decomposition and Euclidean distance between the received symbol vector and temporarily estimated symbol vector by QRD detection. In addition, it is found that the performance of the QRD-M algorithm degrades when the diagonal terms of the channel upper triangle matrix instantaneously decrease. To overcome this problem, the proposed algorithm employs the ratio of each diagonal term and total diagonal terms. Moreover, the proposed algorithm further decreases redundant complexity by considering the location of initial detection symbol in constellation. By doing so, the proposed algorithm effectively achieves performance near to the maximum likelihood detection algorithm, while maintaining the overall average computation complexity much lower than that of the conventional QRD-M systems. Especially, the proposed algorithm achieves reduction of 76% and 26% computational complexity with low signal to noise ratio (SNR) and high SNR, compared with the adaptive QRD-M algorithm based on noise power. Moreover, simulation results show that the proposed algorithm achieves both low complexity and lower symbol error rate compared with the fixed QRD-M algorithms. © 2020 by the authors. Licensee MDPI, Basel, Switzerland.1

    Data of methylome and transcriptome derived from human dilated cardiomyopathy

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    AbstractAlterations in DNA methylation and gene expression have been implicated in the development of human dilated cardiomyopathy (DCM). Differentially methylated probes (DMPs) and differentially expressed genes (DEGs) were identified between the left ventricle (LV, a pathological locus for DCM) and the right ventricle (RV, a proxy for normal hearts). The data in this DiB are for supporting our report entitled “Methylome analysis reveals alterations in DNA methylation in the regulatory regions of left ventricle development genes in human dilated cardiomyopathy” (Bong-Seok Jo, In-Uk Koh, Jae-Bum Bae, Ho-Yeong Yu, Eun-Seok Jeon, Hae-Young Lee, Jae-Joong Kim, Murim Choi, Sun Shim Choi, 2016) [1]

    Mesenteric Pseudocyst of the Small Bowel in Gastric Cancer Patient: A Case Report

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    Mesenteric pseudocyst is rare. This term is used to describe the abdominal cystic mass, without the origin of abdominal organ. We presented a case of mesenteric pseudocyst of the small bowel in a 70-year-old man. Esophago-gastro-duodenoscopy showed a 3.5 cm sized excavated lesion on the posterior wall of angle. Endocopic biopsy confirmed a histologic diagnosis of the poorly differentiated adenocarcinoma, which includes the signet ring cell component. Abdominal computed tomography scan showed a focal mucosal enhancement in the posterior wall of angle of the stomach, a 2.4 cm sized enhancing mass on the distal small bowel loop, without distant metastases or ascites in rectal shelf, and multiple gallbladder stones. The patient underwent subtotal gastrectomy with gastroduodenostomy, segmental resection of the small bowel, and cholecystectomy. The final pathological diagnosis was mesenteric pseudocyst. This is the first case report describing incidentally detected mesenteric pseudocyst of the small bowel in gastric cancer patients

    Effects of PI3Kγ overexpression in the hippocampus on synaptic plasticity and spatial learning

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    Previous studies have shown that a family of phosphoinositide 3-kinases (PI3Ks) plays pivotal roles in the brain; in particular, we previously reported that knockout of the γ isoform of PI3K (PI3Kγ) in mice impaired synaptic plasticity and reduced behavioral flexibility. To further examine the role of PI3Kγ in synaptic plasticity and hippocampus-dependent behavioral tasks we overexpressed p110γ, the catalytic subunit of PI3Kγ, in the hippocampal CA1 region. We found that the overexpression of p110γ impairs NMDA receptor-dependent long-term depression (LTD) and hippocampus-dependent spatial learning in the Morris water maze (MWM) task. In contrast, long-term potentiation (LTP) and contextual fear memory were not affected by p110γ overexpression. These results, together with the previous knockout study, suggest that a critical level of PI3Kγ in the hippocampus is required for successful induction of LTD and normal learning
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