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Search Results: 1 - 10 of 120150 matches for " Yuwei Wang "
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A Novel Method for Segmentation of the Cardiac MR Images using Generalized DDGVF Snake Models with Shape Priors
Lixiong Liu,Yuwei Wu,Yuanquan Wang
Information Technology Journal , 2009,
Abstract: In this study, a novel method is presented for segmentation of the endocardium and epicardium of the left ventricle in cardiac magnetic resonance images using snake models. We first generalize the DDGVF snake model by introducing two spatially varying weighting functions which characterize the boundary information; this generalized DDGVF snake can conquer the spurious edges raised by artifacts while maintaining the desirable properties of DDGVF of distinguishing the positive and negative boundaries. This is especially helpful for the tasks on hand because the endocardium and epicardium of the LV in MR images can be characterized as positive and negative boundaries. Observed that the left ventricle is roughly a circle, a shape constraint based on circle is introduced into the snake model. This new constraint can prevent the snake contour from being trapped and leaking out so as to maintain the global shape of the snake contour during evolution. In addition, fourth-order PDEs are employed for noise removal. We demonstrate the proposed approach on an in vivo dataset and compare the segmented contours with manual collections; the results show its effectiveness.
Trace formula for linear Hamiltonian systems with its applications to elliptic Lagrangian solutions
Xijun Hu,Yuwei Ou,Penghui Wang
Mathematics , 2013, DOI: 10.1007/s00205-014-0810-5
Abstract: In the present paper, we build up trace formulas for both the linear Hamiltonian systems and Sturm-Liouville systems. The formula connects the monodromy matrix of a symmetric periodic orbit with the infinite sum of eigenvalues of the Hessian of the action functional. A natural application is to study the non-degeneracy of linear Hamiltonian systems. Precisely, by the trace formula, we can give an estimation for the upper bound such that the non-degeneracy preserves. Moreover, we could estimate the relative Morse index by the trace formula. Consequently, a series of new stability criteria for the symmetric periodic orbits is given. As a concrete application, the trace formula is used to study the linear stability of elliptic Lagrangian solutions of the classical planar three-body problem. It is well known that the linear stability of elliptic Lagrangian solutions depends on the mass parameter $\bb=27(m_1m_2+m_2m_3+m_3m_1)/(m_1+m_2+m_3)^2\in [0,9]$ and the eccentricity $e\in [0,1)$. Based on the trace formula, we estimate the stable region and hyperbolic region of the elliptic Lagranian solutions.
A Systematic Review of Perceived Insider Status  [PDF]
Liangtie Dai, Yuwei Chen
Journal of Human Resource and Sustainability Studies (JHRSS) , 2015, DOI: 10.4236/jhrss.2015.32010
Abstract: Perceived Insider Status (PIS) is defined as the extent to which an individual employee perceives him or herself as an insider within a particular organization. It represents that employees have earned a “personal space” and acceptance inside their work organization. Researches show that PIS has a strong effect on employee’s job performance and organizational citizenship behavior (OCB), etc. Through a review of PIS, this paper places emphasis on the elaboration of influencing factors and mechanisms of PIS from a concept perspective and tries to shed some light on not only the limitation of current researches, but also the new breakthrough points for future research.
Analysis of Analytic Hierarchy Process to Build a Cities Evaluation System Based on Smart Growth  [PDF]
Mengyue Yang, Yuwei Zhang
Current Urban Studies (CUS) , 2017, DOI: 10.4236/cus.2017.54027
Abstract:
Smart growth is an urban planning theory that originated in 1990’s, which has been gradually focused on by researchers. The theory is in coincidence with China’s strategies that promote urbanization and the transformation of urban development. The goal of this paper is to apply analytic hierarchy process to build an evaluation system of cities based on smart growth. After analyzing the factors that need to be taken into account, we build a hierarchical model and put different weight on different factors that compose the evaluation system of cities. Finally, we use smart growth mode for Jinchang city and point out that the scientific urban planning should be improved in the way of smart growth. The results of this paper can provide some decision-making references for relevant departments.
A Location-Allocation Model for Seaport-Dry Port System Optimization
Xuejun Feng,Yan Zhang,Yuwei Li,Wei Wang
Discrete Dynamics in Nature and Society , 2013, DOI: 10.1155/2013/309585
Abstract: Seaports participate in hinterland economic development through partnerships with dry ports, and the combined seaport-dry port network serves as the backbone of regional logistics. This paper constructs a location-allocation model for the regional seaport-dry port network optimization problem and develops a greedy algorithm and a genetic algorithm to obtain its solution. This model is applicable to situations under which the geographic distribution of demand is known. A case study involving configuration of dry ports near the west bank of the Taiwan Strait is conducted, and the model is successfully applied. 1. Introduction Rapid development of seaports and intermodal transportation systems under integrated planning has made it necessary for seaports to dynamically assess what constitutes their hinterlands, and the scramble for hinterlands by seaports is heating up. On the other hand, it is increasingly recognized by hinterlands that seaports guide and support regional economic development, and there is a growing need to perform in hinterland locations seaports’ functions except ship loading and unloading. The interactions of these two driving forces have induced rapid development of dry ports as both a means by which seaports vie for hinterland access and a means by which hinterlands stimulate economic growth. Logistics networks, each including a group of seaports and some dry ports, are becoming backbones of regional goods movement. At the end of 2011, there were over 100 dry ports built or being built in China, with the Port of Tianjin leading the development of more than 20 of them. There were also a large number of road and rail transportation hubs which were in many aspects similar to dry ports. The development of dry ports can mitigate problems caused by constraints related to land and others that limit seaports’ growth. Dry ports can also coordinate the operation of the port supply chain and support regional economic development. Consequently, dry ports are changing the dynamics of interaction between seaports and hinterlands. This paper studies the location of dry ports from the perspective of seaport-hinterland interaction and optimizes the configuration of the seaport-dry port system, taking into consideration the relationships between dry ports, seaports, and the regional logistics system. On the evolution of a port, Bird [1] developed the Anyport model describing how port infrastructures develop over time and space and how the relationship between ports and their host cities evolves. Three major steps of port development were identified:
Quantum Hydrodynamic Model by Moment Closure of Wigner Equation
Zhenning Cai,Yuwei Fan,Ruo Li,Tiao Lu,Yanli Wang
Physics , 2012, DOI: 10.1063/1.4748971
Abstract: In this paper, we derive the quantum hydrodynamics models based on the moment closure of the Wigner equation. The moment expansion adopted is of the Grad type firstly proposed in \cite{Grad}. The Grad's moment method was originally developed for the Boltzmann equation. In \cite{Fan_new}, a regularization method for the Grad's moment system of the Boltzmann equation was proposed to achieve the globally hyperbolicity so that the local well-posedness of the moment system is attained. With the moment expansion of the Wigner function, the drift term in the Wigner equation has exactly the same moment representation as in the Boltzmann equation, thus the regularization in \cite{Fan_new} applies. The moment expansion of the nonlocal Wigner potential term in the Wigner equation is turned to be a linear source term, which can only induce very mild growth of the solution. As the result, the local well-posedness of the regularized moment system for the Wigner equation remains as for the Boltzmann equation.
Genistein Increases Epidermal Growth Factor Receptor Signaling and Promotes Tumor Progression in Advanced Human Prostate Cancer
Hisae Nakamura,Yuwei Wang,Takeshi Kurita,Hans Adomat,Gerald R. Cunha,Yuzhuo Wang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0020034
Abstract: Genistein is an isoflavone found in soy, and its chemo-preventive and -therapeutic effects have been well established from in vitro studies. Recently, however, its therapeutic actions in vivo have been questioned due to contradictory reports from animal studies, which rely on rodent models or implantation of cell lines into animals. To clarify in vivo effects of genistein in advanced prostate cancer patients, we developed a patient-derived prostate cancer xenograft model, in which a clinical prostatectomy sample was grafted into immune deficient mice. Our results showed an increased lymph node (LN) and secondary organ metastases in genistein-treated mice compared to untreated controls. Interestingly, invasive malignant cells aggregated to form islands/micrometastasis only in the secondary organs of the genistein-treated groups, not in the untreated control group. To understand the underlying mechanism for metastatic progression, we examined cell proliferation and apoptosis on paraffin-sections. Immunohistological data show that tumors of genistein-treated groups have more proliferating and fewer apoptotic cancer cells than those of the untreated group. Our immunoblotting data suggest that increased proliferation and metastasis are linked to enhanced activities of tyrosine kinases, EGFR and its downstream Src, in genistein-treated groups. Despite the chemopreventive effects proposed by earlier in vitro studies, the cancer promoting effect of genistein observed here suggests the need for careful selection of patients and safer planning of clinical trials.
A Novel Xenograft Model in Zebrafish for High-Resolution Investigating Dynamics of Neovascularization in Tumors
Chengjian Zhao, Xiaofei Wang, Yuwei Zhao, Zhimian Li, Shuo Lin, Yuquan Wei, Hanshuo Yang
PLOS ONE , 2011, DOI: 10.1371/journal.pone.0021768
Abstract: Tumor neovascularization is a highly complex process including multiple steps. Understanding this process, especially the initial stage, has been limited by the difficulties of real-time visualizing the neovascularization embedded in tumor tissues in living animal models. In the present study, we have established a xenograft model in zebrafish by implanting mammalian tumor cells into the perivitelline space of 48 hours old Tg(Flk1:EGFP) transgenic zebrafish embryos. With this model, we dynamically visualized the process of tumor neovascularization, with unprecedented high-resolution, including new sprouts from the host vessels and the origination from VEGFR2+ individual endothelial cells. Moreover, we quantified their contributions during the formation of vascular network in tumor. Real-time observations revealed that angiogenic sprouts in tumors preferred to connect each other to form endothelial loops, and more and more endothelial loops accumulated into the irregular and chaotic vascular network. The over-expression of VEGF165 in tumor cells significantly affected the vascularization in xenografts, not only the number and size of neo-vessels but the abnormalities of tumor vascular architecture. The specific inhibitor of VEGFR2, SU5416, significantly inhibited the vascularization and the growth of melanoma xenografts, but had little affects to normal vessels in zebrafish. Thus, this zebrafish/tumor xenograft model not only provides a unique window to investigate the earliest events of tumoral neoangiogenesis, but is sensitive to be used as an experimental platform to rapidly and visually evaluate functions of angiogenic-related genes. Finally, it also offers an efficient and cost-effective means for the rapid evaluation of anti-angiogenic chemicals.
Activation of voltage-gated KCNQ/Kv7 channels by anticonvulsant retigabine attenuates mechanical allodynia of inflammatory temporomandibular joint in rats
Wen Xu, Yuwei Wu, Yeping Bi, Lei Tan, Yehua Gan, KeWei Wang
Molecular Pain , 2010, DOI: 10.1186/1744-8069-6-49
Abstract: In this study, we selected a new anticonvulsant drug retigabine that specifically activates M-current, and investigated the effect of retigabine on inflammation of the temporomandibular joint (TMJ) induced by complete Freund's adjuvant (CFA) in rats. The results show that the head withdrawal threshold for escape from mechanical stimulation applied to facial skin over the TMJ in inflamed rats was significantly lower than that in control rats. Administration of centrally acting M-channel opener retigabine (2.5 and 7.5 mg/kg) can dose-dependently raise the head withdrawal threshold of mechanical allodynia, and this analgesic effect can be reversed by the specific KCNQ channel blocker XE991 (3 mg/kg). Food intake is known to be negatively associated with TMJ inflammation. Food intake was increased significantly by the administration of retigabine (2.5 and 7.5 mg/kg), and this effect was reversed by XE991 (3 mg/kg). Furthermore, intracerebralventricular injection of retigabine further confirmed the analgesic effect of central retigabine on inflammatory TMJ.Our findings indicate that central sensitization is involved in inflammatory TMJ pain and pharmacological intervention for controlling central hyperexcitability by activation of neuronal KCNQ/M-channels may have therapeutic potential for TMDs.Temporomandibular disorders (TMDs) are an assortment of clinical conditions characterized by pain in the temporomandibular joint (TMJ) and/or the masticatory muscles [1]. The main symptoms exhibited by TMD patients include orofacial pain, altered jaw mechanics, impaired masticatory function and sounds from the TMJ, with few or no peripheral tissue abnormalities [2]. As TMD pain persists over time, it is thought that changes in the central nervous system (CNS) lead to altered neuronal processing in the brain, with central sensitization and hyperexcitability, ultimately affecting perception of TMD pain [3,4]. Accumulating clinical evidence shows that patients with TMDs have generali
Molecular evolution of influenza A (H3N2) viruses circulated in Fujian Province, China during the 1996–2004 period
WenQiong Xiu,YuWei Wen,XiaoNa Shen,JianFeng Xie,ShiQin Yang,BingShan Wu,MeiAi Wang
Science China Life Sciences , 2008, DOI: 10.1007/s11427-008-0050-8
Abstract: We studied the genetic and epidemic characteristics of influenza A (H3N2) viruses circulated in human in Fujian Province, south of China from 1996 to 2004. Phylogenetic analysis was carried out for genes encoding hemagglutinin1 (HA1) of influenza A virus (14 new and 11 previously reported reference sequences). Our studies revealed that in the 8 flu seasons, the mutations of HA1 genes occurred from time to time, which were responsible for about four times of antigenic drift of influenza H3N2 viruses in Fujian, China. The data demonstrated that amino acid changes were limited to some key codons at or near antibody binding sites A through E on the HA1 molecule. The changes at the antibody binding site B or A or sialic acid receptor binding site 226 were critical for antigenic drift. But the antigenic sites might change and the key codons for antigenic drift might change as influenza viruses evolve. It seems important to monitor new H3 isolates for mutations in the positively selected codons of HA1 gene in south of Asia.
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