Chen K.,Central South UniversityChangsha |
Zhang Z.,Central South UniversityChangsha |
Long J.,Central South UniversityChangsha |
Zhang H.,Central South UniversityChangsha
Expert Systems with Applications | Year: 2016
Massive textual data management and mining usually rely on automatic text classification technology. Term weighting is a basic problem in text classification and directly affects the classification accuracy. Since the traditional TF-IDF (term frequency & inverse document frequency) is not fully effective for text classification, various alternatives have been proposed by researchers. In this paper we make comparative studies on different term weighting schemes and propose a new term weighting scheme, TF-IGM (term frequency & inverse gravity moment), as well as its variants. TF-IGM incorporates a new statistical model to precisely measure the class distinguishing power of a term. Particularly, it makes full use of the fine-grained term distribution across different classes of text. The effectiveness of TF-IGM is validated by extensive experiments of text classification using SVM (support vector machine) and kNN (k nearest neighbors) classifiers on three commonly used corpora. The experimental results show that TF-IGM outperforms the famous TF-IDF and the state-of-the-art supervised term weighting schemes. In addition, some new findings different from previous studies are obtained and analyzed in depth in the paper. © 2016 Elsevier Ltd
Chen S.B.,Central South UniversityChangsha |
Wang H.D.,Central South UniversityChangsha |
Wan W.,Central South UniversityChangsha |
Huang X.,Central South UniversityChangsha
Energy Materials: Materials Science and Engineering for Energy Systems | Year: 2013
Homogeneous precipitation method was applied to synthesise Ca2Co2O5 powders using calcium nitrate, cobalt nitrate and urea as raw materials. Uniform plate-like Ca2Co2O5 powders with an average grain size of 1 mm can be obtained by calcining the precursor for 8 h at 1073 K in the air. The Ca2Co2O5 ceramics were gained after sintering for 4 h at 1083 K using uniaxial pressure moulding and then sintering technique. The thermoelectric properties of ceramic samples were measured from 303 to 973 K, and the result shows that the electrical conductivity, Seebeck coefficient, thermal conductivity and figure of merit of the sample are 2236.85 S m-1, 175.95 μV K-1, 1.01 W m-1 K-1 and 0.69 at 973 K respectively. © 2013 Institute of Materials, Minerals and Mining.
Peng Q.,University of Toronto |
Peng Q.,Central South UniversityChangsha |
Jia S.H.,University of Toronto |
Parodo J.,University of Toronto |
And 2 more authors.
American Journal of Physiology - Endocrinology and Metabolism | Year: 2015
Pre-B cell colony-enhancing factor (PBEF) is a highly conserved pleiotropic protein reported to be an alternate ligand for the insulin receptor (IR). We sought to clarify the relationship between PBEF and insulin signaling by evaluating the effects of PBEF on the localization of the IR(3 chain to lipid rafts in A549 epithelial cells. We isolated lipid rafts from A549 cells and detected the IR by immunoprecipitation from raft fractions or whole cell lysates. Cells were treated with rPBEF, its enzymatic product nicotinamide adenine dinucleotide (NAD), or the Nampt inhibitor daporinad to study the effect of PBEF on IRβ movement. We used coimmunoprecipitation studies in cells trans-fected with PBEF and IRβ constructs to detect interactions between PBEF, the IRβ, and caveolin-1 (Cav-1). PBEF was present in both lipid raft and nonraft fractions, whereas the IR was found only in lipid raft fractions of resting A549 cells. The IR-, PBEF-, and Cav-1-coimmunoprecipitated rPBEF treatment resulted in the movement of IRβ- and tyrosine-phosphorylated Cav-1 from lipid rafts to nonrafts, an effect that could be blocked by daporinad, suggesting that this effect was facilitated by the Nampt activity of PBEF. The addition of PBEF to insulin-treated cells resulted in reduced Akt phosphorylation of both Ser473 and Thr308. We conclude that PBEF can inhibit insulin signaling through the IR by Nampt-dependent promotion of IR translocation into the nonraft domains of A549 epithelial cells. PBEF-induced alterations in the spatial geometry of the IR provide a mechanistic explanation for insulin resistance in inflammatory states associated with upregulation of PBEF. © 2015 the American Physiological Society.
Wu H.,Central South UniversityChangsha |
Zhao M.,Central South UniversityChangsha |
Tan L.,Central South UniversityChangsha |
Lu Q.,Central South UniversityChangsha
Autoimmunity Reviews | Year: 2016
Systemic lupus erythematosus (SLE) is an autoimmune disease with multiple organ involvement. It is characterized by abundant autoantibodies that form immune complex with autoantigens and deposit in organs and cause tissue damage by inducing inflammation. The pathogenesis of SLE has been intensively studied but remains unclear. B and T lymphocyte abnormalities, dysregulation of apoptosis, defects in the clearance of apoptotic materials, and various genetic and epigenetic factors are believed to contribute to the initiation and development of SLE. The up-to-date research findings point to the relationship between abnormal DNA methylation and SLE, which has attracted considerable interest worldwide. Besides the global hypomethylation on lupus T and B cells, the gene specific and site-specific methylation has been identified and documented to be responsible for SLE. The purpose of this review was to present and summarize the association between aberrant DNA methylation of immune cells and SLE, the possible mechanisms of immune dysfunction caused by DNA methylation, and to better understand the roles of aberrant DNA methylation in the initiation and development of SLE and to provide an insight into the related diagnosis biomarkers and therapeutic options in SLE. © 2016 Elsevier B.V.
Gummow R.J.,James Cook UniversityTownsville |
Sharma N.,University of South Australia |
Feng R.,James Cook UniversityTownsville |
Feng R.,Pennsylvania State UniversityUniversity Park |
And 3 more authors.
Journal of the Electrochemical Society | Year: 2013
Li1.0(Li1/7Mn4/7 Ni2/7]O2 cathode material was prepared by a facile, one-pot synthesis method. The structure of the material was determined by Rietveld refinement of structural models using high-resolution synchrotron X-ray and neutron powder diffraction data and was found to consist of two distinct phases. The major phase, with composition Li1.25(3)Ni0.17(1) Mn0.61(1)O2, close to the well-characterized Li1.2Ni0.2Mn0.6O2 composition can be described as an intergrowth structure of Li2MnO3.i and LiMn0.5Ni0.5O2 domains and the second phase is a lithium-deficient layered structure with refined composition Li0.85(1)Ni0.57(1)Mn0.55(1)O2. The composite cathode has a high initial discharge capacity of 250 mAh/g which drops to 225 mAh/g on the 2nd discharge cycle. This capacity is maintained on .subsequent cycles. Time-resolved in-situ synchrotron XRD data was used to study the changes in the lattice parameters and phase evolution of the two phases during Li-insertion and extraction. © 2013 The Electrochemical Society. All rights reserved.
Huang X.,Central South UniversityChangsha |
Liu Z.,Central South UniversityChangsha |
Pu W.,Second Xiangya Hospital |
Zhou L.,Central South UniversityChangsha |
And 6 more authors.
Journal of Magnetic Resonance Imaging | Year: 2016
Purpose: To explore the acute effect of betel quid (BQ) use on functional network connectivity by comparing the global functional brain networks and their subsets before and immediately after BQ chewing. Materials and Methods: Resting-state functional magnetic resonance imaging (fMRI) was performed in 27 healthy male participants before and just after chewing BQ on a 3.0T scanner with a gradient-echo echo planar imaging sequence. Independent component analysis (ICA) was used to determine components that represent the brain's functional networks and their spatial aspects of functional connectivity. A paired t-test was used for exploring the connectivity differences in each network before and after BQ chewing. Results: Sixteen networks were identified by ICA. Nine of them showed connectivity differences before and after BQ chewing (P < 0.05 false discovery rate corrected): (A) orbitofrontal, (B) left frontoparietal, (C) visual, (D) right frontoparietal, (E) anterior default mode, (F) medial frontal/anterior cingulate (G) frontotemporal, (H) occipital/parietal, (I) occipital/temporal/cerebellum. Moreover, networks A, B, C, D, G, H, and I showed increased connectivity, while networks E and F showed decreased connectivity in participants after BQ chewing compared to before chewing. Conclusion: The acute effects of BQ use appear to actively alter functional connectivity of frontal and default networks that are known to play a key role in addictive behavior. J. Magn. Reson. Imaging 2016. © 2016 Wiley Periodicals, Inc.
PubMed | Central South UniversityChangsha and Central South University
Type: Journal Article | Journal: American journal of translational research | Year: 2016
Norcantharidin (NCTD) has been proven to be able to attenuate renal interstitial fibrosis, but the exact molecular mechanism is still unknown. This study investigated the relationship between the anti-fibrotic effect of NCTD and its inhibition on PP2Ac expression. Here, PP2Ac was found to be positively correlated with extracellular matrix accumulation in the rat unilateral ureteral obstruction (UUO) model. Additional experiments showed that the PP2A inhibitor (okadaic acid) can ameliorate renal interstitial fibrosis by inhibiting the expression of fibronectin (FN) and collagen I (Col-I) and reversing tubular epithelial-to-mesenchymal transition in vivo and in vitro. In vitro experiments also demonstrated that ectopic over-expression of PP2Ac has a profibrotic effect in HK-2 cells. Moreover, NCTD was able to downregulate PP2Ac expression, decrease FN, Col-I, -SMA expression, and increase E-cadherin expression in a dose-dependent manner both in vivo and in vitro. In particular, it was demonstrated that NCTD induced no evident changes in the expression of FN, Col-I, -SMA and E-cadherin in HK-2 cells after PP2Ac was knocked down by shRNA. These results indicated that NCTD exerts an anti-fibrosis effect via inhibition of PP2Ac expression. Thus, PP2Ac could be a promising target for intervention in renal interstitial fibrosis.
PubMed | Fujian Medical University, Central South UniversityChangsha and Central South University
Type: | Journal: Frontiers in pharmacology | Year: 2016
PubMed | Central South UniversityChangsha and Central South University
Type: | Journal: Frontiers in pharmacology | Year: 2016
Tigecycline (TIG), the first member of glycylcycline bacteriostatic agents, has been approved to treat complicated infections in the clinic because of its expanded-spectrum antibiotic potential. Recently, an increasing number of studies have emphasized the anti-tumor effects of TIG. The inhibitory effects of TIG on cancer depend on several activating signaling pathways and abnormal mitochondrial function in cancer cells. The aim of this review is to summarize the cumulative anti-tumor evidence supporting TIG activity against different cancer types, including acute myeloid leukemia (AML), glioma, non-small cell lung cancer (NSCLC), among others. In addition, the efficacy and side effects of TIG in cancer patients are summarized in detail. Future clinical trials are also to be discussed that will evaluate the security and validate the underlying the tumor-killing properties of TIG.
PubMed | Central South UniversityChangsha
Type: Journal Article | Journal: Autoimmunity reviews | Year: 2016
Systemic lupus erythematosus (SLE) is an autoimmune disease with multiple organ involvement. It is characterized by abundant autoantibodies that form immune complex with autoantigens and deposit in organs and cause tissue damage by inducing inflammation. The pathogenesis of SLE has been intensively studied but remains unclear. B and T lymphocyte abnormalities, dysregulation of apoptosis, defects in the clearance of apoptotic materials, and various genetic and epigenetic factors are believed to contribute to the initiation and development of SLE. The up-to-date research findings point to the relationship between abnormal DNA methylation and SLE, which has attracted considerable interest worldwide. Besides the global hypomethylation on lupus T and B cells, the gene specific and site-specific methylation has been identified and documented to be responsible for SLE. The purpose of this review was to present and summarize the association between aberrant DNA methylation of immune cells and SLE, the possible mechanisms of immune dysfunction caused by DNA methylation, and to better understand the roles of aberrant DNA methylation in the initiation and development of SLE and to provide an insight into the related diagnosis biomarkers and therapeutic options in SLE.