Modified Constraint Scores for Semi-Supervised Feature Selection

Jianqiao Wang,Yuehua Li,Kun Chen 보안공학연구지원센터 2014 International Journal of Signal Processing, Image Vol.7 No.5

Semi-supervised constraint scores, which utilize both pairwise constraints and the local property of the unlabeled data to select features, achieve comparable performance to the supervised feature selection methods. The local property is characterized without considering the pairwise constraints and these two conditions are introduced independently. However, the pairwise constraints and the local property may contain conflicting information. In this paper, we utilize the conflicting information to improve the local property. Instead of characterizing the local property by all neighbors, samples which do not appear in the cannot-link constraints can be used. A performance indicator, called neighborhood-cannot-link (NC) coefficient, is proposed to measure the improvement of the local property. We use the improved local property and the pairwise constraints to perform semi-supervised constraint scores algorithm. Experiments on several real world data sets demonstrate the effectiveness of the methods.

System Simulation Modeling for Near-field Millimeter Wave Synthetic Aperture Imaging Radiometer

Jianfei Chen,Yuehua Li,Jianqiao Wang,Yuanjiang Li 보안공학연구지원센터(IJSIP) 2014 International Journal of Signal Processing, Image Vol.7 No.6

Due to the fact that theoretical analysis and instrument construction for antenna array of synthetic aperture imaging radiometer (SAIR) are both complicated, and designers usually hope to predict the imaging effect and analysis the influence of relevant parameters of SAIR before the system design. The imaging simulation is a very useful method in the system design of SAIR. This paper is devoted to establishing an accurate imaging model for simulating the process of near-field millimeter wave SAIR. In this model, the target radiation signals and received signals of receivers are represented by the accurate signals in the time domain, which improves the efficiency of this simulation model significantly. The visibility function is collected by the cross-correlation between I/Q signals of the antenna pairs just as the imaging process of the practical SAIR. Some characteristics (such as the coherence between targets, the resolution and no-aliasing FOV of SAIR and so on) are verified by the corresponding 1D and 2D simulation experiments, and the effectiveness of this imaging model is also tested by these simulation experiments. The simulation experiment results show that this model is an efficient, accurate imaging simulation model, and can be employed in the system design of near-field millimeter wave SAIR.

Polyetheretherketone implants with hierarchical porous structure for boosted osseointegration

Zhiyong Chen,Yu Chen,Yang Wang,JiaJia Deng,Xin Wang,Qingqing Wang,Yuehua Liu,Jiandong Ding,Lin Yu 한국생체재료학회 2023 생체재료학회지 Vol.27 No.00

Background Good osseointegration is the key to the long-term stability of bone implants. Thermoplastic polyetheretherketone (PEEK) has been widely used in orthopedics; however, its inherent biological inertia causes fibrous tissue to wrap its surface, which leads to poor osseointegration and thus greatly limits its clinical applications. Methods Herein, we developed a facile yet effective surface modification strategy. A commonly used sulfonation coupled with “cold pressing” treatment in the presence of porogenic agent formed a three-dimensional hierarchical porous structure on PEEK surface. Subsequently, the effects of porous surface on the in vitro adhesion, proliferation and differentiation of rat bone marrow-derived mesenchymal stem cells (BMSCs) were evaluated. Finally, the osteoinduction and osseointegration of surface-porous PEEK implant were examined in the rat distal femoral defect model. Results In vitro results showed that the surface modification did not significantly affect the mechanical performance and cytocompatibility of PEEK substance, and the porous structure on the modified PEEK substrate provided space for cellular ingrowth and enhanced osteogenic differentiation and mineralization of BMSCs. In vivo tests demonstrated that the surface-porous PEEK implant could effectively promote new bone formation and had higher bone-implant contact rate, thereby achieving good bone integration with the surrounding host bone. In addition, this modification technique was also successfully demonstrated on a medical PEEK interbody fusion cage. Conclusion The present study indicates that topological morphology plays a pivotal role in determining implant osseointegration and this facile and effective modification strategy developed by us is expected to achieve practical applications quickly.

Study of the Non-Linearity on TiO2(0 0 1) Surface with Oxygen Defects: A First-Principles Study

Yuehua Dai,Xu Zhang,Chengzhi Ma,Zhiyong Pan,Feifei Wang,Wenjuan Lu,Jin Yang,Fei Yang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2017 NANO Vol.12 No.8

First-principles plane-wave pseudopotential calculations were performed to study the energetics and electronic structures of oxygen defects on rutile TiO2(0 0 1). The influence of the material thickness on non-linearity (NL) was studied. With the increase in the thickness, the NL became stronger. Calculating the site-projected density of states by applying an external electric field showed that the NL of the bulk is due to the exchange of electrons between O 2p orbitals and Ti 3d orbitals. Finally, the influence of oxygen defects—oxygen vacancies (Vo), oxygen interstitials (Oi), and oxygen vacancies/oxygen interstitial (Vo + Oi) pairs (Frenkel pair defects)—on the NL of TiO2 was studied. These results demonstrate that the band gap (Eg) of TiO2 became gradually narrower as the electric field increased. The Stark effect and defects can lead to the splitting of degenerate energy levels. Stronger electric fields increase the band splitting and reduce Eg. With the increase in the Vo concentration, the decrease in the splitting amplitude and width of the energy level lead to weakening of the transfer of electrons between O and Ti atoms and optimizing the NL of TiO2. Therefore, the incorporation of Vo plays a significant role in improving the NL of TiO2.

Effect of Graphene/TiO2 (001) Interface on Threshold Voltage and Nonlinearity

Yuehua Dai,Shanshan Gong,Zhisheng Zhong,Fengyu Gao,Feifei Wang,Cheng Ding,Jin Yang,Fei Yang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.6

In this work, the threshold voltage (Vth) and nonlinearity (NL) of Graphene (Gra)/TiO2/Gra heterojunction were studied. First, the density functional tight binding (DFTB+) and much more dynamics were used to investigate the IV curves and the resistive switching properties of TiO2 slab and Gra/TiO2/Gra heterojunction. The NL of Gra/TiO2/Gra heterojunction is stronger than that of the TiO2 slab. The Vth of the resistive transition of the heterojunction is larger than that of the TiO2 slab. The tunneling probabilities and the Mulliken atomic population at the Gra/TiO2 interface under different electric fields were calculated by the Cambridge sequential total energy package (CASTEP). Results showed that both the parameters evidently increased under a certain numerical electric field. Finally, the movement of atom in the electric field and the change in the chemical bond were simulated by DFTB+ module. The effect of the Gra/TiO2 interface on Vth and NL was further illustrated. Postponed Vth and improved NL were found at the heterojunction relative to the TiO2 slab due to the presence of the interface barrier. This work provides guidance and reference for design and optimization of TiO2-based selectors.

Prevalence of Decreased Myocardial Blood Flow in Symptomatic Patients with Patent Coronary Stents: Insights from Low-Dose Dynamic CT Myocardial Perfusion Imaging

Yuehua Li,Mingyuan Yuan,Mengmeng Yu,Zhigang Lu,Chengxing Shen,Yining Wang,Bin Lu,Jiayin Zhang 대한영상의학회 2019 Korean Journal of Radiology Vol.20 No.4

Objective: To study the prevalence and clinical characteristics of decreased myocardial blood flow (MBF) quantified by dynamic computed tomography (CT) myocardial perfusion imaging (MPI) in symptomatic patients without in-stent restenosis. Materials and Methods: Thirty-seven (mean age, 71.3 ± 10 years; age range, 48–88 years; 31 males, 6 females) consecutive symptomatic patients with patent coronary stents and without obstructive de novo lesions were prospectively enrolled to undergo dynamic CT-MPI using a third-generation dual-source CT scanner. The shuttle-mode acquisition technique was used to image the complete left ventricle. A bolus of contrast media (50 mL; iopromide, 370 mg iodine/mL) was injected into the antecubital vein at a rate of 6 mL/s, followed by a 40-mL saline flush. The mean MBF value and other quantitative parameters were measured for each segment of both stented-vessel territories and reference territories. The MBFratio was defined as the ratio of the mean MBF value of the whole stent-vessel territory to that of the whole reference territory. An MBFratio of 0.85 was used as the cut-off value to distinguish hypoperfused from non-hypoperfused segments. Results: A total of 629 segments of 37 patients were ultimately included for analysis. The mean effective dose of dynamic CT-MPI was 3.1 ± 1.2 mSv (range, 1.7–6.3 mSv). The mean MBF of stent-vessel territories was decreased in 19 lesions and 81 segments. Compared to stent-vessel territories without hypoperfusion, the mean MBF and myocardial blood volume were markedly lower in hypoperfused stent-vessel territories (77.5 ± 16.6 mL/100 mL/min vs. 140.4 ± 24.1 mL/100 mL/min [p < 0.001] and 6.4 ± 3.7 mL/100 mL vs. 11.5 ± 4 mL/100 mL [p < 0.001, respectively]). Myocardial hypoperfusion in stentvessel territories was present in 48.6% (18/37) of patients. None of clinical parameters differed statistically significantly between hypoperfusion and non-hypoperfusion subgroups. Conclusion: Decreased MBF is commonly present in patients who are symptomatic after percutaneous coronary intervention, despite patent stents and can be detected by dynamic CT-MPI using a low radiation dose.

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.

Isometric Cost-Sensitive Laplacian Eigenmaps for Imbalance Radar Target Recognition

Xingjian Xu,Yuehua Li,Jianqiao Wang 보안공학연구지원센터(IJSIP) 2014 International Journal of Signal Processing, Image Vol.7 No.4

Parallel Gene Loss and Acquisition Among Strains of Different Brucella Species and Biovars

Zhijun Zhong,Yufei Wang,Jie Xu,Yanfen Chen,Yuehua Ke,Xiaoyan Zhou,Xitong Yuan,Dongsheng Zhou,Yi Yang,Ruifu Yang,Guangneng Peng,Hai Jiang,Jing Yuan,Hongbin Song,Buyun Cui,Liuyu Huang,Zeliang Chen 한국미생물학회 2012 The journal of microbiology Vol.50 No.4

The genus Brucella is divided into six species; of these, B. melitensis and B. abortus are pathogenic to humans, and B. ovis and B. neotomae are nonpathogenic to humans. The definition of gene loss and acquisition is essential for understanding Brucella’s ecology, evolutionary history, and host relationships. A DNA microarray containing unique genes of B. melitensis Type strain 16MT and B. abortus 9-941 was constructed and used to determine the gene contents of the representative strains of Brucella. Phylogenetic relationships were inferred from sequences of housekeeping genes. Gene loss and acquisition of different Brucella species were inferred. A total of 214 genes were found to be differentially distributed,and 173 of them were clustered into 15 genomic islands (GIs). Evidence of horizontal gene transfer was observed for 10GIs. Phylogenetic analysis indicated that the 19 strains formed five clades, and some of the GIs had been lost or acquired independently among the different lineages. The derivation of Brucella lineages is concomitant with the parallel loss or acquisition of GIs, indicating a complex interaction between various Brucella species and hosts.

LAMP, PCR, and real-time PCR detection of Acetobacter aceti in yogurt

Wei Zhou,Yan Zhang,Shuang Wang,Yuehua Li,Jingjing Zhang,Cuixia Zhang,Zan Wang,Zhisheng Zhang 한국식품과학회 2017 Food Science and Biotechnology Vol.26 No.1

Acetic acid bacteria (AAB) can spoil food. Acetobacter aceti as a core subgroup of AAB is usually isolated from yogurt. A. aceti should be timely and effectively detected to prevent yogurt contamination. The present study focused on A. aceti to establish an assay that can be performed to detect AAB in yogurt. LAMP, PCR, and real-time PCR were applied and compared for detecting A. aceti from pure culture and artificially contaminated yogurt samples. In pure culture, LAMP showed the highest detection sensitivity with 10−1 CFU/mL. For yogurt samples, the sensitivity limit of LAMP was 102 CFU/mL, which was lower than that of real-time PCR (101 CFU/mL). The results indicated that these methods could be quickly and efficiently applied to detect A. aceti. As LAMP technology has low cost and high detection efficiency, it can potentially be applied for detecting A. aceti in production and quality control programs of yogurt.