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Search Results: 1 - 10 of 28240 matches for " Xuzhen Zhu "
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Personalized recommendation with corrected similarity
Xuzhen Zhu,Hui Tian,Shimin Cai
Computer Science , 2014, DOI: 10.1088/1742-5468/2014/07/P07004
Abstract: Personalized recommendation attracts a surge of interdisciplinary researches. Especially, similarity based methods in applications of real recommendation systems achieve great success. However, the computations of similarities are overestimated or underestimated outstandingly due to the defective strategy of unidirectional similarity estimation. In this paper, we solve this drawback by leveraging mutual correction of forward and backward similarity estimations, and propose a new personalized recommendation index, i.e., corrected similarity based inference (CSI). Through extensive experiments on four benchmark datasets, the results show a greater improvement of CSI in comparison with these mainstream baselines. And the detailed analysis is presented to unveil and understand the origin of such difference between CSI and mainstream indices.
Predicting missing links via significant paths
Xuzhen Zhu,Hui Tian,Shimin Cai,Tao Zhou
Computer Science , 2014, DOI: 10.1209/0295-5075/106/18008
Abstract: Link prediction plays an important role in understanding intrinsic evolving mechanisms of networks. With the belief that the likelihood of the existence of a link between two nodes is strongly related with their similarity, many methods have been proposed to calculate node similarity based on node attributes and/or topological structures. Among a large variety of methods that take into account paths connecting the target pair of nodes, most of which neglect the heterogeneity of those paths. Our hypothesis is that a path consisting of small-degree nodes provides a strong evidence of similarity between two ends, accordingly, we propose a so-called sig- nificant path index in this Letter to leverage intermediate nodes' degrees in similarity calculation. Empirical experiments on twelve disparate real networks demonstrate that the proposed index outperforms the mainstream link prediction baselines.
Personalized recommendation against crowd's popular selection
Xuzhen Zhu,Hui Tian,Haifeng Liu,Shimin Cai
Computer Science , 2014,
Abstract: The problem of personalized recommendation in an ocean of data attracts more and more attention recently. Most traditional researches ignore the popularity of the recommended object, which resulting in low personality and accuracy. In this Letter, we proposed a personalized recommendation method based on weighted object network, punishing the recommended object that is the crowd's popular selection, namely, Anti-popularity index(AP), which can give enhanced personality, accuracy and diversity in contrast to mainstream baselines with a low computational complexity.
Consistence beats causality in recommender systems
Xuzhen Zhu,Hui Tian,Zheng Hu,Ping Zhang,Tao Zhou
Computer Science , 2015,
Abstract: The explosive growth of information challenges people's capability in finding out items fitting to their own interests. Recommender systems provide an efficient solution by automatically push possibly relevant items to users according to their past preferences. Recommendation algorithms usually embody the causality from what having been collected to what should be recommended. In this article, we argue that in many cases, a user's interests are stable, and thus the previous and future preferences are highly consistent. The temporal order of collections then does not necessarily imply a causality relationship. We further propose a consistence-based algorithm that outperforms the state-of-the-art recommendation algorithms in disparate real data sets, including \textit{Netflix}, \textit{MovieLens}, \textit{Amazon} and \textit{Rate Your Music}.
Approximate Analysis of Power Offset over Spatially Correlated MIMO Channels  [PDF]
Guangwei YU, Xuzhen WANG
Communications and Network (CN) , 2009, DOI: 10.4236/cn.2009.11004
Abstract: Power offset is zero-order term in the capacity versus signal-to-noise ratio curve. In this paper, approximate analysis of power offset is presented to describe MIMO system with uniform linear antenna arrays of fixed length. It is assumed that the number of receive antenna is larger than that of transmit antenna. Spatially Correlated MIMO Channel is approximated by tri-diagonal toeplitz matrix. The determinant of tri-diagonal toeplitz matrix, which is fitted by elementary curve, is one of the key factors related to power offset. Based on the curve fitting, the determinant of tri-diagonal toeplitz matrix is mathematically tractable. Consequently, the expression of local extreme points can be derived to optimize power offset. The simulation results show that approximation above is accurate in local extreme points of power offset. The proposed expression of local extreme points is helpful to approach optimal power offset.
Establishment and Characterization of 7 Novel Hepatocellular Carcinoma Cell Lines from Patient-Derived Tumor Xenografts
Hong Xin, Ke Wang, Gang Hu, Fubo Xie, Kedong Ouyang, Xuzhen Tang, Minjun Wang, Danyi Wen, Yizhun Zhu, Xiaoran Qin
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0085308
Abstract: Hepatocellular carcinoma (HCC) is a common cancer with poor prognosis worldwide and the molecular mechanism is not well understood. This study aimed to establish a collection of human HCC cell lines from patient-derived xenograft (PDX) models. From the 20 surgical HCC sample collections, 7 tumors were successfully developed in immunodeficient mice and further established 7 novel HCC cell lines (LIXC002, LIXC003, LIXC004, LIXC006, LIXC011, LIXC012 and CPL0903) by primary culture. The characterization of cell lines was defined by morphology, growth kinetics, cell cycle, chromosome analysis, short tandem repeat (STR) analysis, molecular profile, and tumorigenicity. Additionally, response to clinical chemotherapeutics was validated both in vitro and in vivo. STR analysis indicated that all cell lines were unique cells different from known cell lines and free of contamination by bacteria or mycoplasma. The other findings were quite heterogeneous between individual lines. Chromosome aberration could be found in all cell lines. Alpha-fetoprotein was overexpressed only in 3 out of 7 cell lines. 4 cell lines expressed high level of vimentin. Ki67 was strongly stained in all cell lines. mRNA level of retinoic acid induced protein 3 (RAI3) was decreased in all cell lines. The 7 novel cell lines showed variable sensitivity to 8 tested compounds. LIXC011 and CPL0903 possessed multiple drug resistance property. Sorafenib inhibited xenograft tumor growth of LIXC006, but not of LIXC012. Our results indicated that the 7 novel cell lines with low passage maintaining their clinical and pathological characters could be good tools for further exploring the molecular mechanism of HCC and anti-cancer drug screening.
Sequence variations of theS7 ribosomal protein gene in primitive cyprinid fishes: Implication on phylogenetic analysis
Xuzhen Wang,Shunping He,Yiyu Chen
Chinese Science Bulletin , 2002, DOI: 10.1007/BF03184114
Abstract: Cyprinidae is the largest fish family in the world and contains about 210 genera and 2010 species. Appropriate DNA markers must be selected for the phylogenetic analyses of Cyprinidae. In present study, the 1st intron of the S7 ribosomal protein (r-protein) gene is first used to examine the relationships among cyprinid fishes. The length of the 1st intron obtained by PCR amplification ranges from 655 to 859 bp in the 16 cyprinid species investigated, and is 602 bp inMyxocyprinus asiaticus. Out of the alignment of 925 nucleotide sites obtained, the parsimony informative sites are 499 and occupy 54% of the total sites. The results indicate that the 1st intron sequences of the S7 r-protein gene in cyprinids are rich in informative sites and vary remarkably in sequence divergence from 2.3% between close species to 66.6% between distant species. The bootstrap values of the interior nodes in the NJ (neighbor-joining) and MP (mostparsimony) trees based on the present S7 r-protein gene data are higher than those based on cytochrome b and the d-loop region respectively. Therefore, the 1st intron sequences of the S7 r-protein gene in cyprinids are sensitive enough for phylogenetic analyses, and the 1st intron is an appropriate genetic marker for the phylogenetic reconstruction of the taxa in different cyprinid subfamilies. However, attempts to discuss whether the present S7 r-protein gene data can be applied to the phylogeny of the taxa at the level of the family or the higher categories in Cypriniformes need further studies.
Molecular variation and evolution of the tyrosine kinase domains of insulin receptor IRa and IRb genes in Cyprinidae
XiangHui Kong,XuZhen Wang,ShunPing He
Science China Life Sciences , 2011, DOI: 10.1007/s11427-011-4189-3
Abstract: The insulin receptor (IR) gene plays an important role in regulating cell growth, differentiation and development. In the present study, DNA sequences of insulin receptor genes, IRa and IRb, were amplified and sequenced from 37 representative species of the Cyprinidae and from five outgroup species from non-cyprinid Cypriniformes. Based on coding sequences (CDS) of tyrosine kinase regions of IRa and IRb, molecular evolution and phylogenetic relationships were analyzed to better understand the characteristics of IR gene divergence in the family Cyprinidae. IRa and IRb were clustered into one lineage in the gene tree of the IR gene family, reconstructed using the unweighted pair group method with arithmetic mean (UPGMA). IRa and IRb have evolved into distinct genes after IR gene duplication in Cyprinidae. For each gene, molecular evolution analyses showed that there was no significant difference among different groups in the reconstructed maximum parsimony (MP) tree of Cyprinidae; IRa and IRb have been subjected to similar evolutionary pressure among different lineages. Although the amino acid sequences of IRa and IRb tyrosine kinase regions were highly conserved, our analyses showed that there were clear sequence variations between the tyrosine kinase regions of IRa and IRb proteins. This indicates that IRa and IRb proteins might play different roles in the insulin signaling pathway.
A Determination of Potential α-Glucosidase Inhibitors from Azuki Beans (Vigna angularis)
Yang Yao,Xuzhen Cheng,Lixia Wang,Suhua Wang,Guixing Ren
International Journal of Molecular Sciences , 2011, DOI: 10.3390/ijms12106445
Abstract: A 70% ethanol extract from azuki beans ( Vigna angularis) was extracted further with CH 2Cl 2, EtOAc and n-BuOH to afford four fractions: CH 2Cl 2-soluble, EtOAc-soluble, n-BuOH-soluble and residual extract fractions. The EtOAc-soluble fractions showed the highest α-glucosidase inhibitory activity. Two pure flavonoid compounds, vitexin and isovitexin, were isolated (using the enzyme assay-guide fractionation method) from the EtOAc-soluble fractions. We further evaluated the interaction between the flavonoid compounds and α-glucosidase by fluorescence spectroscopy. Vitexin and isovitexin showed high inhibitory activities, with IC 50 values of 0.4 mg·mL ?1 and 4.8 mg·mL ?1, respectively. This is the first study of the active compositions of azuki beans against α-glucosidase.
Biological Potential of Sixteen Legumes in China
Yang Yao,Xuzhen Cheng,Lixia Wang,Suhua Wang,Guixing Ren
International Journal of Molecular Sciences , 2011, DOI: 10.3390/ijms12107048
Abstract: Phenolic acids have been identified in a variety of legumes including lima bean, broad bean, common bean, pea, jack bean, goa bean, adzuki bean, hyacinth bean, chicking vetch, garbanzo bean, dral, cow bean, rice bean, mung bean and soybean. The present study was carried out with the following aims: (1) to identify and quantify the individual phenolic acid and determine the total phenolic content (TPC); (2) to assess their antioxidant activity, inhibition activities of α-glucosidase, tyrosinase, and formation of advanced glycation endproducts; and (3) to investigate correlations among the phytochemicals and biological activity. Common bean possesses the highest antioxidant activity and advanced glycation endproducts formation inhibition activity. Adzuki bean has the highest α-glucosidase inhibition activity, and mung bean has the highest tyrosinase inhibition activity. There are significant differences in phytochemical content and functional activities among the bean species investigated. Selecting beans can help treat diseases such as dermatological hyperpigmentation illness, type 2 diabetes and associated cardiovascular diseases.
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