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Search Results: 1 - 10 of 127170 matches for " LI Xiangyan "
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Dependence of the Structure, Optical Phonon Modes and Dielectric Properties on Pressure in Wurtzite GaN and AlN  [PDF]
Huanyou Wang, Yaqi Chen, Yalan Li, Xiangyan He
Advances in Materials Physics and Chemistry (AMPC) , 2015, DOI: 10.4236/ampc.2015.58031
Abstract: The density functional perturbation theory (DFPT) is employed to study the structure, optical phonon modes and dielectric properties for wurtzite GaN and AlN under hydrostatic pressure. In order to calculate accurately the Born effective charges and high frequency dielectric tensors, we utilize two sum rules to monitor this calculation. The calculated optical phonon frequencies and longitudinal-transverse splitting show an increasing with pressure, whereas the Born effective charges and high frequency dielectric tensors are found to decrease with pressure. In particular, we analysed the reason for discrepancy between this calculation and previous experimental determination of pressure dependence of the LO-TO splitting in AlN. The different pressure behavior of the structural and lattice-dynamical properties of GaN and AlN is discussed in terms of the strengths of the covalent bonds and crystal anisotropy. Our results regarding dielectric Grüneisen parameter are predictions and may serve as a reference.
The genome of herpes simplex virus type 1 is prone to form short repeat sequences  [PDF]
Xiangyan Zhao, Xiaolong Wu, Lv Qin, Zhongyang Tan, Shifang Li, Qingjian Ouyang, You Tian
Journal of Biosciences and Medicines (JBM) , 2013, DOI: 10.4236/jbm.2013.13006
Abstract:

Herein, we report a very high content of simple sequence repeats (SSRs) covering 66.12% of the herpes simplex virus type 1 (HSV-1) genome when a low threshold is adopted to define SSRs, indicating that repeat sequence is a very important character of the HSV-1 genome. The repeats with two iterations account for 68.33% of the total repeats. In reality, the genome of HSV-1 is prone to form shorter repeat sequences. For mono-, di- and trinucleotide repeats, the repeat numbers decreased with the increase of repeats iterations, implicating that the formation tendency of SSRs might be from low iterations to high iterations. The high iterations SSRs might have subjected to strong selected pressure and survived to perform different functions. The analysis suggested that the repeats formation may be an essential evolutionary driving force for the HSV-1 genome, and the results might be helpful for studying the genome structure, repeats genesis and genome evolution of HSV-1.

An Influence Study on Adopting Will of Tourism Mobile E-commerce by the Perceived Risk and Trust  [PDF]
Jiajing Hu, Xiangyan Liu
iBusiness (IB) , 2013, DOI: 10.4236/ib.2013.51B009
Abstract: With the rapid development of China's tourism e-commerce and sophisticating mobile technologies, more and more Chinese tourists, with online shopping experience and mobile devices usage, have accepted the this newly emerging mode---tourism mobile e-commerce. However, the perceived risk and lack of trust are still the main factors impeding its growth. By exploratory factor analysis, the perceived risk in this paper is divided into four dimensions, personal risk propensity, product risk, technical risk and environmental risk. With them as the antecedents, a hypothesis model is established among perceived risk, trust and adopting will of tourism mobile e-commerce. It turns out that tourists' personal risk propensity has a positive correlation with product risk, technical risk and environmental risk, while the perceived risk has a negative one with trust, through which it indirectly affects the adopting will.
A reconstruction method of porous media integrating soft data with hard data
DeTang Lu,Ting Zhang,JiaQing Yang,DaoLun Li,XiangYan Kong
Chinese Science Bulletin , 2009, DOI: 10.1007/s11434-009-0327-8
Abstract: The three-dimensional reconstruction of porous media is of great significance to the research of mechanisms of fluid flow. The real three-dimensional structural data of porous media are helpful to describe the irregular topologic structures in porous media. The reconstruction of porous media will be inaccurate while only hard data or no conditional data are available. Reconstructed results can be more accurate, using soft data during reconstruction. Integrating soft data with hard data, a method based on multiple-point geostatistics (MPS) is proposed to reconstruct three-dimensional structures of porous media. The variogram curves and permeability, computed by lattice Boltzmann method (LBM), of the reconstructed images and the target image obtained from real volume data were compared, showing that the structural characteristics of reconstructed porous media using both soft data and hard data as conditional data are most similar to those of real volume data.
A reconstruction method of porous media integrating soft data with hard data

DeTang Lu,Ting Zhang,JiaQing Yang,DaoLun Li,XiangYan Kong,

科学通报(英文版) , 2009,
Abstract: The three-dimensional reconstruction of porous media is of great significance to the research of mechanisms of fluid flow. The real three-dimensional structural data of porous media are helpful to describe the irregular topologic structures in porous media. The reconstruction of porous media will be inaccurate while only hard data or no conditional data are available. Reconstructed results can be more accurate, using soft data during reconstruction. Integrating soft data with hard data, a method based on multiple-point geostatistics (MPS) is proposed to reconstruct three-dimensional structures of porous media. The variogram curves and permeability, computed by lattice Boltzmann method (LBM), of the reconstructed images and the target image obtained from real volume data were compared, showing that the structural characteristics of reconstructed porous media using both soft data and hard data as conditional data are most similar to those of real volume data. Supported by the National Basic Research Program of China (Grant No. 2006CB705805) and National Natural Science Foundation of China (Grant Nos. 10672159, 10702069)
A Clustering Algorithm for Key Frame Extraction Based on Density Peak  [PDF]
Hong Zhao, Tao Wang, Xiangyan Zeng
Journal of Computer and Communications (JCC) , 2018, DOI: 10.4236/jcc.2018.612012
Abstract:
Aiming at the problem of video key frame extraction, a density peak clustering algorithm is proposed, which uses the HSV histogram to transform high-dimensional abstract video image data into quantifiable low-dimensional data, and reduces the computational complexity while capturing image features. On this basis, the density peak clustering algorithm is used to cluster these low-dimensional data and find the cluster centers. Combining the clustering results, the final key frames are obtained. A large number of key frame extraction experiments for different types of videos show that the algorithm can extract different number of key frames by combining video content, overcome the shortcoming of traditional key frame extraction algorithm which can only extract a fixed number of key frames, and the extracted key frames can represent the main content of video accurately.
MicroRNA-185 and 342 Inhibit Tumorigenicity and Induce Apoptosis through Blockade of the SREBP Metabolic Pathway in Prostate Cancer Cells
Xiangyan Li, Yi-Ting Chen, Sajni Josson, Nishit K. Mukhopadhyay, Jayoung Kim, Michael R. Freeman, Wen-Chin Huang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0070987
Abstract: MicroRNA (miRNA or miR) inhibition of oncogenic related pathways has been shown to be a promising therapeutic approach for cancer. Aberrant lipid and cholesterol metabolism is involved in prostate cancer development and progression to end-stage disease. We recently demonstrated that a key transcription factor for lipogenesis, sterol regulatory element-binding protein-1 (SREBP-1), induced fatty acid and lipid accumulation and androgen receptor (AR) transcriptional activity, and also promoted prostate cancer cell growth and castration resistance. SREBP-1 was overexpressed in human prostate cancer and castration-resistant patient specimens. These experimental and clinical results indicate that SREBP-1 is a potential oncogenic transcription factor in prostate cancer. In this study, we identified two miRNAs, miR-185 and 342, that control lipogenesis and cholesterogenesis in prostate cancer cells by inhibiting SREBP-1 and 2 expression and down-regulating their targeted genes, including fatty acid synthase (FASN) and 3-hydroxy-3-methylglutaryl CoA reductase (HMGCR). Both miR-185 and 342 inhibited tumorigenicity, cell growth, migration and invasion in prostate cancer cell culture and xenograft models coincident with their blockade of lipogenesis and cholesterogenesis. Intrinsic miR-185 and 342 expression was significantly decreased in prostate cancer cells compared to non-cancerous epithelial cells. Restoration of miR-185 and 342 led to caspase-dependent apoptotic death in prostate cancer cells. The newly identified miRNAs, miR-185 and 342, represent a novel targeting mechanism for prostate cancer therapy.
Achyranthes bidentata Polypeptides Reduces Oxidative Stress and Exerts Protective Effects against Myocardial Ischemic/Reperfusion Injury in Rats
Ru Tie,Lele Ji,Ying Nan,Wenqing Wang,Xiangyan Liang,Fei Tian,Wenjuan Xing,Miaozhang Zhu,Rong Li,Haifeng Zhang
International Journal of Molecular Sciences , 2013, DOI: 10.3390/ijms141019792
Abstract: Achyranthes bidentata, a Chinese medicinal herb, is reported to be neuroprotective. However, its role in cardioprotection remains largely unknown. Our present study aimed to investigate the effects of Achyranthes bidentata polypeptides (ABPP) preconditioning on myocardial ischemia/reperfusion (MI/R) injury and to test the possible mechanisms. Rats were treated with ABPP (10 mg/kg/d, i.p.) or saline once daily for one week. Afterward, all the animals were subjected to 30 min of myocardial ischemia followed by 4 h of reperfusion. ABPP preconditioning for one week significantly improved cardiac function following MI/R. Meanwhile, ABPP reduced infarct size, plasma creatine kinase (CK)/lactate dehydrogenase (LDH) activities and myocardial apoptosis at the end of reperfusion in rat hearts. Moreover, ABPP preconditioning significantly inhibited superoxide generation, gp91 ph ox expression, malonaldialdehyde formation and enhanced superoxide dismutase activity in I/R hearts. Furthermore, ABPP treatment inhibited PTEN expression and increased Akt phosphorylation in I/R rat heart. PI3K inhibitor wortmannin blocked Akt activation, and abolished ABPP-stimulated anti-oxidant effect and cardioprotection. Our study demonstrated for the first time that ABPP reduces oxidative stress and exerts cardioprotection against MI/R injury in rats. Inhibition of PTEN and activation of Akt may contribute to the anti-oxidant capacity and cardioprotection of ABPP.
A STUDY ON THE RHEOLOGICAL MODEL OF POROUS MEDIA
多孔介质的流变模型研究

Li Chuanliang Kong Xiangyan Du Zhimin Xu Xianzhi Li Peichao,
李传亮
,孔祥言,杜志敏,徐献芝,李培超

力学学报 , 2003,
Abstract: Porous media are a special kind of material, which consists of skeleton particles and pores between. Pores are usually saturated with one or several kinds of fluids. Normally, porous media suffer both an outer stress (total stress) and an inner stress (pore pressure or fluid pressure) simultaneously. So, an effective stress is necessary in the study of deformation behavior of porous media. The effective stress is an equivalent stress, which alone yields the same strain behavior with the two stresses applying on porous media outside and inside. K.Terzaghi proposed the first effective stress of porous media for soil mechanics in 1923, which is the simple difference between the outer stress and the inner stress. The Terzaghi effective stress concept is widely used not only in soil mechanics but also in rock mechanics. However, a recent research discovered that porous media have two effective stresses: the Primary effective stress and the Structural effective stress, named as the Double Effective Stresses of porous media. Actually, the Terzaghi effective stress is only an approximation to the structural effective stress.Corresponding to the Double Effective Stresses, porous media have two kinds of deformation mechanism: the elastic deformation (the Primary deformation) and the viscous deformation (the Structural deformation), which is related to the special material structure of porous media. The primary effective stress yields elastic strain in porous media while the structural effective stress yields viscous strain. The total strain of porous media is the sum of elastic strain and viscous strain. The rheological model to calculate the total strain of porous media must adopt both the primary effective stress and the structural effective stress(the double effective stresses) for the calculations of elastic strain and viscous strain respectively. However, the conventional rheological model adopts the Terzaghi effective stress alone to calculate the two kinds of strain, which cannot fit the strain behavior of porous media properly. The new model with double effective stresses, proposed in this paper, can simulate practical strain behavior of porous media and also unite porous media and solids through property parameters.
Alpha-Linolenic Acid Exerts an Endothelial Protective Effect against High Glucose Injury via PI3K/Akt Pathway
Wei Zhang, Rong Li, Jia Li, Wenqing Wang, Ru Tie, Fei Tian, Xiangyan Liang, Wenjuan Xing, Yong He, Liang Yu, Miaomiao Xi, Siwang Wang, Qiangsun Zheng, Haifeng Zhang
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0068489
Abstract: Mounting evidence has indicated that the cardiovascular protective effects of dietary alpha-linolenic acid (ALA), but whether ALA exerts an endothelial protective effect against high glucose injury and the underlying mechanisms remain largely unknown. Streptozocin-induced diabetic rats were randomized treated orally for 4 weeks with vehicle (0.01% alcohol) or ALA (500 μg/kg per day by gavage). Human umbilical vein endothelial cells (HUVECs) were exposed to high glucose (28 mmol/L) stimulation for 48 hours. ALA significantly improved concentration-dependent vasorelaxation to ACh in diabetic aortic segments and inhibited endothelial inflammation as evidenced by decreased soluble P-selectin and intercellular adhesion molecule-1 (ICAM-1) in diabetic rats. Furthermore, both P-selectin and ICAM-1 expression were increased significantly in high glucose-induced HUVECs, resulting in enhanced neutrophils adhesion to HUVECs compared with normal glucose group. Treatment with ALA (50 μmol/L) increased Akt phosphorylation, attenuated P-selectin and ICAM-1 expressions and thus inhibited neutrophils adhesion in HUVECs exposed to high glucose, all of which was blocked by the PI3K inhibitors LY294002 and wortmannin. These data indicates that ALA inhibits endothelial inflammation and improved endothelial function in STZ-induced diabetic rats. The anti-adhesive effect of ALA against high glucose injury may partially be mediated by the PI3K/Akt pathway.
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