Compressive Sensing based Random Access for Vehicle-to-Roadside Communications

Xiaochen Wang,Rong Ran,Hayoung Oh 한국통신학회 2017 한국통신학회 학술대회논문집 Vol.2017 No.6

Genetic Analysis and Serological Detection of Novel O-Antigen Gene Clusters of Plesiomonas shigelloides

( Xiaochen Wang ),( Daoyi Xi ),( Yuehua Li ),( Junxiang Yan ),( Jingyun Zhang ),( Xi Guo ),( Boyang Cao ) 한국미생물생명공학회(구 한국산업미생물학회) 2021 Journal of microbiology and biotechnology Vol.31 No.4

Plesiomonas shigelloides, a member of the family Vibrionaceae, is a gram-negative, rod-shaped, facultative anaerobic bacterium with flagella. P. shigelloides has been isolated from such sources as freshwater, surface water, and many wild and domestic animals. P. shigelloides contains 102 Oantigens and 51 H-antigens. The diversity of O-antigen gene clusters is relatively poorly understood. In addition to O1 and O17 reported by other laboratories, and the 12 O serogroups (O2, O10, O12, O23, O25, O26, O32, O33, O34, O66, O75, and O76) reported previously by us, in the present study, nine new P. shigelloides serogroups (O8, O17, O18, O37, O38, O39, O44, O45, and O61) were sequenced and annotated. The genes for the O-antigens of these nine groups are clustered together in the chromosome between rep and aqpZ. Only O38 possesses the wzm and wzt genes for the synthesis and translocation of O-antigens via the ATP-binding cassette (ABC) transporter pathway; the other eight use the Wzx/Wzy pathway. Phylogenetic analysis using wzx and wzy showed that both genes are diversified. Among the nine new P. shigelloides serogroups, eight use wzx/wzy genes as targets. In addition, we developed an O-antigen-specific PCR assay to detect these nine distinct serogroups with no cross reactions among them.

Self-weighted quantile estimation of autoregressive conditional duration model

Wang Xiaochen,Song Yuping 한국통계학회 2022 Journal of the Korean Statistical Society Vol.51 No.1

An efficient market is often related to the market liquidity in a certain sense. In this paper, the autoregressive conditional duration (ACD) model is used for modeling and analyzing the market liquidity based on high-frequency financial data, which takes the volume duration as its measure index. Considering the high peak and heavy tail of high-frequency financial data, the self-weighted quantile regression (SQR) estimators for the unknown parameters in ACD model are constructed. The consistency and asymptotic properties of the estimators are proved. Furthermore, Monte Carlo simulation shows that the SQR estimators with data-driven weights are more accurate than those by traditional quantile regression (QR). Moreover, the performance of SQR estimation performs better with the increase of the proportion of outliers. The mean deviation and mean square error are reduced up to 96.24% and 91.83%, respectively. Finally, we illustrate the SQR method by an empirical analysis of the volume duration for Industrial And Commercial Bank Of China (ICBC) and PingAn Bank stocks in China. Through the Akaike Information Criterion (AIC) and other evaluation criteria, the SQR estimators at different quantiles all possess better performance.

Deletion of cg1360 Affects ATP Synthase Function and Enhances Production of L-Valine in Corynebacterium glutamicum

( Xiaochen Wang ),( Hongyu Yang ),( Wei Zhou ),( Jun Liu ),( Ning Xu ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.8

Bacterial ATP synthases drive ATP synthesis by a rotary mechanism, and play a vital role in physiology and cell metabolism. Corynebacterium glutamicum is well known as an industrial workhorse for amino acid production, and its ATP synthase operon contains eight structural genes and two adjacent genes, cg1360 and cg1361. So far, the physiological functions of Cg1360 (GenBank CAF19908) and Cg1361 (GenBank CAF19909) remain unclear. Here, we showed that Cg1360 was a hydrophobic protein with four transmembrane helices (TMHs), while no TMH was found in Cg1361. Deletion of cg1360, but not cg1361, led to significantly reduced cell growth using glucose and acetic acid as carbon sources, reduced F1 portions in the membrane, reduced ATP-driven proton-pumping activity and ATPase activity, suggesting that Cg1360 plays an important role in ATP synthase function. The intracellular ATP concentration in the Δcg1360 mutant was decreased to 72% of the wild type, while the NADH and NADPH levels in the Δcg1360 mutant were increased by 29% and 26%, respectively. However, the Δcg1361 mutant exhibited comparable intracellular ATP, NADH and NADPH levels with the wild-type strain. Moreover, the effect of cg1360 deletion on L-valine production was examined in the L-valine-producing V-10 strain. The final production of L-valine in the V-10-Δcg1360 mutant reached 9.2 ± 0.3 g/l in shake flasks, which was 14% higher than that of the V-10 strain. Thus, Cg1360 can be used as an effective engineering target by altering energy metabolism for the enhancement of amino acid production in C. glutamicum.

Clinical Application of MRI in an Animal Bone Graft Model

Xiaochen Liu,Wenxiao Jia,Gele Jin,Hong Wang,Jingxu Ma,Yunling Wang,Yi Yang,Wei Deng 한국자기학회 2013 Journal of Magnetics Vol.18 No.2

We aim to monitor vascularization of early bone perfusion following rabbit lumbar intertransverse bone graft fusion surgery using magnetic resonance imaging assessment. Correlation with graft survival status was evaluated by histological method. Experimental animals were randomly divided into three groups and the model was established by operating bilateral lumbar intertransverse bone graft with different types of bone graft substitute material. The lumbar intertransverse area of three groups of rabbits was scanned via MRI. In addition, histological examinations were performed at the 6<SUP>th</SUP> week after surgery and the quantitative analysis of the osteogenesis in different grafted area was carried out by an image analysis system. The MRI technique can be used for early postoperative evaluation of vascularized bone graft perfusion after transplantation of different bone materials, whereas histological examination allows direct visualization of the osteogenesis process.

Early Plasma Circulating Tumor DNA as a Potential Biomarker of Disease Recurrence in Non-metastatic Prostate Cancer

Xiaochen Fei,Xinxing Du,Yiming Gong,Jiazhou Liu,Liancheng Fan,Jiayi Wang,Yanqing Wang,Yinjie Zhu,Jiahua Pan,Baijun Dong,Wei Xue 대한암학회 2023 Cancer Research and Treatment Vol.55 No.3

Purpose In non-metastatic prostate cancer (nmPCa) setting, it is important to early identify the patients at risk of biochemical recurrence (BCR) for immediate postoperative intervention. Our study aimed to evaluate the potential clinical utility of circulating tumor DNA (ctDNA) for predicting disease recurrence.Materials and Methods This real-world observational study evaluated 161 cases of nmPCa undergoing next-generation sequencing at our institution. A total of 139 ctDNA samples and 31 biopsied tumor tissue underwent genomic profiling. The study endpoint was BCR after radical prostatectomy. Relationships between the ctDNA status and the biochemical progression-free survival (bPFS) were analyzed by log-rank test and multivariate Cox regression.Results Of 161 enrolled patients, 19 (11.8%) harbored deleterious alterations in <i>NCOR2</i>, followed by <i>BRCA2</i> (3.7%), <i>ATR</i> (2.5%), and <i>CDK12</i> (2.5%). Of available pre-operative blood samples (n=139), ctDNA was detectable in 91 (65.5%). Until last follow-up, 56 of 68 patients (85.3%) with detectable ctDNA had achieved BCR, whereas only eight of 39 patients (20.5%) with undetectable ctDNA had achieved BCR. Patients who had undetectable ctDNA experienced significantly longer bPFS compared with those who had detectable ctDNA (not available vs. 8.2 months; hazard ratio, 0.14; p < 0.01). Pre-operative ctDNA status was a significant prognostic factor of disease recurrence.Conclusion Pre-operative ctDNA detection could identify patients at high risk of recurrence and has the potential to inform immediate postoperative interventions, but these approaches remain to be validated in prospective studies. ctDNA studies can provide insights into accurate monitoring and precise treatment rather than simply following routine clinical care.

C-LLC-LL resonant converter with wide-gain-range and low-stress for hold-up operation

Ma, Xiaochen,Wang, Ping,Wang, Zhishuang,Li, Bo The Korean Institute of Power Electronics 2021 JOURNAL OF POWER ELECTRONICS Vol.21 No.9

For applications with hold-up time requirements, the LCLC converter can achieve a wider voltage gain range than the LLC converter without degrading the normal operation efficiency due to its variable-magnetizing-inductor (VML) structure, which is formed by an inductor and an additional capacitor. However, the wide gain range achieved by the VML is at the expense of a high resonant voltage stress of the VML's capacitor, which affects the converter volume/cost. Hence, to solve the contradiction between wide gain range and low capacitor voltage stress when the VML technique is adopted for hold-up operation, this paper proposes a novel C-LLC-LL converter. Specifically, the VML is arranged into a novel C-dual-LL structure. By relying on the unique output voltages relation between C-dual-LL's two branches, the reduced voltage stress of the VML's capacitor and the expanded voltage gain range can be simultaneously realized. To evaluate the feasibility of the proposed solution, a comprehensive analysis is conducted, and experimental results obtained from a 500-W C-LLC-LL prototype are also provided.

Helicobacter pylori-Induced Progranulin Promotes the Progression of the Gastric Epithelial Cell Cycle by Regulating CDK4

Ren Zongjiao,Li Jiayi,Du Xianhong,Shi Wenjing,Guan Fulai,Wang Xiaochen,Wang Linjing,Wang Hongyan 한국미생물·생명공학회 2022 Journal of microbiology and biotechnology Vol.32 No.7

Helicobacter pylori, a group 1 carcinogen, colonizes the stomach and affects the development of stomach diseases. Progranulin (PGRN) is an autocrine growth factor that regulates multiple cellular processes and plays a tumorigenic role in many tissues. Nevertheless, the mechanism of action of PGRN in gastric cancer caused by H. pylori infection remains unclear. Here, we investigated the role of PGRN in cell cycle progression and the cell proliferation induced by H. pylori infection. We found that the increased PGRN was positively associated with CDK4 expression in gastric cancer tissue. PGRN was upregulated by H. pylori infection, thereby promoting cell proliferation, and that enhanced level of proliferation was reduced by PGRN inhibitor. CDK4, a target gene of PGRN, is a cyclin-dependent kinase that binds to cyclin D to promote cell cycle progression, which was upregulated by H. pylori infection. We also showed that knockdown of CDK4 reduced the higher cell cycle progression caused by upregulated PGRN. Moreover, when the PI3K/Akt signaling pathway (which is promoted by PGRN) was blocked, the upregulation of CDK4 mediated by PGRN was reduced. These results reveal the potential mechanism by which PGRN plays a major role through CDK4 in the pathological mechanism of H. pylori infection.

Robust Secure Transmit Design with Artificial Noise in the Presence of Multiple Eavesdroppers

( Xiaochen Liu ),( Yuanyuan Gao ),( Nan Sha ),( Guozhen Zang ),( Shijie. Wang ) 한국인터넷정보학회 2021 KSII Transactions on Internet and Information Syst Vol.15 No.6

This paper studies secure wireless transmission from a multi-antenna transmitter to a single-antenna intended receiver overheard by multiple eavesdroppers with considering the imperfect channel state information (CSI) of wiretap channel. To enhance security of communication link, the artificial noise (AN) is generated at transmitter. We first design the robust joint optimal beamforming of secret signal and AN to minimize transmit power with constraints of security quality of service (QoS), i.e., minimum allowable signal-to-interference-and-noise ratio (SINR) at receiver and maximum tolerable SINR at eavesdroppers. The formulated design problem is shown to be nonconvex and we transfer it into linear matrix inequalities (LMIs). The semidefinite relaxation (SDR) technique is used and the approximated method is proved to solve the original problem exactly. To verify the robustness and tightness of proposed beamforming, we also provide a method to calculate the worst-case SINR at eavesdroppers for a designed transmit scheme using semidefinite programming (SDP). Additionally, the secrecy rate maximization is explored for fixed total transmit power. To tackle the nonconvexity of original formulation, we develop an iterative approach employing sequential parametric convex approximation (SPCA). The simulation results illustrate that the proposed robust transmit schemes can effectively improve the transmit performance.

Surface morphology and deuterium retention in W and W-HfC alloy exposed to high flux D plasma irradiation

Wang Yongkui,Huang Xiaochen,Zhou Jiafeng,Fang Jun,Gao Yan,Ge Jinlong,Miao Shu,Xie Zhuoming 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.2

In this work, pure W and W-0.5wt%HfC alloy (WHC05) were fabricated by sintering and hot-rolling following the same processing route. After exposing to a high flux deuterium plasma irradiation with the Dþ flux to three fluences of 6.00 1024, 2.70 1025 and 7.02 1025 D/m2, the evolution of surface morphology, deuterium retention and hardening behaviors in pureWand WHC05 has been studied. The SEM results show the formation of D blisters on the irradiated area, and with the increase of D implantation, the size of these blisters increases from 200 ~ 500 nm (2.70 1025 D/m2) to 1 ~ 2 mm (7.02 1025 D/m2) in WHC05 and from 1 ~ 2 mm (2.70 1025 D/m2) to > 3 mm (7.02 1025 D/m2) in pure W, respectively. A higher D retention and obvious hardening are observed in pure W than that of the WHC05 alloy, indicating an improve radiation resistance in WHC05 compared to pure W.