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Search Results: 1 - 10 of 27795 matches for " HU Xiaobin "
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Role of Intestinal Hydrolase in the Absorption of Prenylated Flavonoids Present in Yinyanghuo
Yan Chen,Jinyan Wang,Xiaobin Jia,Xiaobin Tan,Ming Hu
Molecules , 2011, DOI: 10.3390/molecules16021336
Abstract: Purpose: Yinyanghuo (Herba Epimdii) is a traditional Chinese herb containing prenylated flavonoids as its active constituents. The aim of this study was to examine the significance of the intestinal hydrolysis of prenylated flavonoids by lactase phlorizin hydrolase (LPH), an enzyme at the brush border membrane of intestinal cells. Methods: A four-site perfused rat intestinal model was used. The concentration of the flavonoids of interest and their metabolites in different intestinal segements were analyzed by HPLC, and the apparent permeabilities were calculated. A lactase phlorizin hydrolase inhibitor (gluconolactone) was employed to investigate the mechanism of the intestinal absorption, and the metabolites of the four flavonoids were identified using LC/MS/MS. Results: Diglycosides (icariin) or triglycosides (epimedin A, epimedin B, and epimedin C) were hydrolyzed rapidly in duodenum and jejunum producing one or two metabolites, while a monoglycoside (baohuoside I) was absorbed directly. When co-perfused with glucono-lactone, both the hydrolysis of diglycosides and triglycosides were significantly inhibited, with inhibition rates for icariin (62%, 50%, 40%, 46%), epimedin A, (55%, 26%, 21%, 14%); epimedin B (42%, 40%, 74%, 22%), and epimedin C (42%, 40%, 52%, 35%) in duodenum, jejunum, ileum, and colon, respectively. Also the metabolites of icariin, epimedin A, epimedin B, and epimedin C were identified as baohuoside I (one of two), sagittatoside A, sagittatoside B, and 2"-O-rhamnosylicariside II, respectively. Conclusions: The results showed that lactase phlorizin hydrolase was a major determinant of the intestinal absorption of prenylated flavonoids present in Yinyanghuo.
Entrepreneurship in Market Process  [PDF]
Xiaobin Peng
Modern Economy (ME) , 2019, DOI: 10.4236/me.2019.103039
Abstract: Based on the market process theory of the Austrian School of Economics, the article explores entrepreneurship in the market process, pointing out that market process is opposite to statics equilibrium. Under statics equilibrium, it is hard to analyze entrepreneurship by economics. Entrepreneurship only exists in the market process. The article argues that in market process, entrepreneurship is reflected in entrepreneur’ behavior, including undertaking the uncertainty of business, combining heterogeneous capital, building the structure of capital. Profit-driven entrepreneur unintentionally makes economic society progress. Entrepreneurship is not only relative with entrepreneur’s personal interest, but also economic society of the entire human.
Phytoremediation of mercury and cadmium polluted wetland by Arundo donax
芦竹修复镉汞污染湿地的研究

HAN Zhiping,HU Xiaobin,HU Zhenghai,
韩志萍

应用生态学报 , 2005,
Abstract: With a pot culture of simulated mercury (Hg) and cadmium (Cd)-polluted wetland, this paper studied the capability of Arundo donax in accumulating these heavy metals, and their distribution in the plant. The results showed that after grown in a 101 mg.kg(-1) Hg-polluted wetland for 8 months, the Hg-concentrating capability of Arundo donax was in order of root > stem > leaf, and the Hg concentration in its aboveground parts was 200 +/- 20 mg.kg(-1) (DW); while in the case of 115 mg.kg(-1) Cd-pollution, the Cd-concentrating capability was in order of leaf > root > stem, and the Cd concentration in leaf was 160 +/- 26 mg.kg(-1) (DW). The heavy metals concentration in Arundo donax organs increased with its growth time, being 30%-50% higher for 8 months than for 4 months. The BCF (Bio-concentration factor) decreased with increasing heavy metals concentration. In polluted wetland, the BCFs of Hg by the leaf and stem were 1.9 and 2.1, and those of Cd were 1.5 and 0.3, respectively; while in unpolluted wetland, the concentration of Hg and Cd was 6.8 and 8.5 mg.kg(-1), the BCFs of Hg by the leaf and stem were 6.8 and 12.2, and those of Cd were 7.0 and 2.7, respectively. It was indicated that Arundo donax not only had the characters of large biomass, exuberant root, and good adaptability, but also exhibited high tolerance and concentrating capability to Cd and Hg.
The Pharmacokinetics of Raloxifene and Its Interaction with Apigenin in Rat
Yan Chen,Xiaobin Jia,Jian Chen,Jinyan Wang,Ming Hu
Molecules , 2010, DOI: 10.3390/molecules15118478
Abstract: Purpose: Raloxifene is a selective estrogen receptor modulator which is structurally similar to tamoxifen. As flavonoids can interact with raloxifene in vitro, we evaluated the in vivo pharmacokinetics of raloxifene in rats when co-administered with apigenin. Methods: The pharmacokinetics of raloxifene in the absence or presence of apigenin was investigated in rats after different dosage regimens. The plasma concentrations before and after enzymatic hydrolysis were analyzed by HPLC, and the pharmacokinetic profiles of raloxifene administered alone and in combination with apigenin were compared. Results: Co-administration of apigenin with raloxifene in a 1:2 ratio by weight resulted in a 55% and 37% increase in the Cmax and AUC of intact raloxifene, respectively. When equal proportions of raloxifene and apigenin (1:1) were administered, the Cmax and AUC of intact raloxifene were increased by 173% and 97% respectively. This increase in intact raloxifene was not associated with an increase in total raloxifene (intact plus conjugated raloxifene) because AUC and Cmax of total raloxifene when administered alone or in combination with apigenin were found to be similar. The results indicated that apigenin inhibited the glucuronidation and sulfation of raloxifene in the intestine bringing about an increased bioavailability of the drug. Conclusions: The results showed that apigenin decreased the first-pass metabolism of raloxifene but did not increase its absorption from the gastrointestinal tract.
Smoothness of density and ergodicity for state-dependent switching diffusions
Yaozhong Hu,David Nualart,Xiaobin Sun,Yingchao Xie
Mathematics , 2014,
Abstract: This paper is concerned with a class of stochastic differential equations with state-dependent switching. The Malliavin calculus is used to study the smoothness of the density of the solutions under the Hormander type conditions. Moreover, the strong Feller property of the process is obtained by using the Bismut formula. Theirreducibility of the semigroup associated with the equations is discussed under some natural conditions. As a consequence the existence and uniqueness of the invariant measure and then the ergodicity for the equations are also discussed.
Smoothness of the joint density for spatially homogeneous SPDEs
Yaozhong Hu,Jingyu Huang,David Nualart,Xiaobin Sun
Mathematics , 2014,
Abstract: In this paper we consider a general class of second order stochastic partial differential equations on $\mathbb{R}^d$ driven by a Gaussian noise which is white in time and it has a homogeneous spatial covariance. Using the techniques of Malliavin calculus we derive the smoothness of the density of the solution at a fixed number of points $(t,x_1), \dots, (t,x_n)$, $t>0$, assuming some suitable regularity and non degeneracy assumptions. We also prove that the density is strictly positive in the interior of the support of the law.
Approximate Solution of Fuzzy Matrix Equations with LR Fuzzy Numbers  [PDF]
Xiaobin Guo, Dequan Shang
Advances in Pure Mathematics (APM) , 2012, DOI: 10.4236/apm.2012.26056
Abstract: In the paper, a class of fuzzy matrix equations AX=B where A is an m × n crisp matrix and is an m × p arbitrary LR fuzzy numbers matrix, is investigated. We convert the fuzzy matrix equation into two crisp matrix equations. Then the fuzzy approximate solution of the fuzzy matrix equation is obtained by solving two crisp matrix equations. The existence condition of the strong LR fuzzy solution to the fuzzy matrix equation is also discussed. Some examples are given to illustrate the proposed method. Our results enrich the fuzzy linear systems theory.
Computational evaluation of TIS annotation for prokaryotic genomes
Gang-Qing Hu, Xiaobin Zheng, Li-Ning Ju, Huaiqiu Zhu, Zhen-Su She
BMC Bioinformatics , 2008, DOI: 10.1186/1471-2105-9-160
Abstract: Based on a homogeneity assumption that gene translation-related signals are uniformly distributed across a genome, we have established a computational method for a large-scale quantitative assessment of the reliability of TIS annotations for any prokaryotic genome. The method consists of modeling a positional weight matrix (PWM) of aligned sequences around predicted TISs in terms of a linear combination of three elementary PWMs, one for true TIS and the two others for false TISs. The three elementary PWMs are obtained using a reference set with highly reliable TIS predictions. A generalized least square estimator determines the weighting of the true TIS in the observed PWM, from which the accuracy of the prediction is derived. The validity of the method and the extent of the limitation of the assumptions are explicitly addressed by testing on experimentally verified TISs with variable accuracy of the reference sets. The method is applied to estimate the accuracy of TIS annotations that are provided on public databases such as RefSeq and ProTISA and by programs such as EasyGene, GeneMarkS, Glimmer 3 and TiCo. It is shown that RefSeq's TIS prediction is significantly less accurate than two recent predictors, Tico and ProTISA. With convincing proofs, we show two general preferential biases in the RefSeq annotation, i.e. over-annotating the longest open reading frame (LORF) and under-annotating ATG start codon. Finally, we have established a new TIS database, SupTISA, based on the best prediction of all the predictors; SupTISA has achieved an average accuracy of 92% over all 532 complete genomes.Large-scale computational evaluation of TIS annotation has been achieved. A new TIS database much better than RefSeq has been constructed, and it provides a valuable resource for further TIS studies.To initiate translation in prokaryote, a ribosome binds to a specific region of mRNA and then recognizes a nearby start codon. The position of the first nucleotide base pair (bp) in
Leaderless genes in bacteria: clue to the evolution of translation initiation mechanisms in prokaryotes
Xiaobin Zheng, Gang-Qing Hu, Zhen-Su She, Huaiqiu Zhu
BMC Genomics , 2011, DOI: 10.1186/1471-2164-12-361
Abstract: Here, we study signals in translation initiation regions of all genes over 953 bacterial and 72 archaeal genomes, then make an effort to construct an evolutionary scenario in view of leaderless genes in bacteria. With an algorithm designed to identify multi-signal in upstream regions of genes for a genome, we classify all genes into SD-led, TA-led and atypical genes according to the category of the most probable signal in their upstream sequences. Particularly, occurrence of TA-like signals about 10 bp upstream to translation initiation site (TIS) in bacteria most probably means leaderless genes.Our analysis reveals that leaderless genes are totally widespread, although not dominant, in a variety of bacteria. Especially for Actinobacteria and Deinococcus-Thermus, more than twenty percent of genes are leaderless. Analyzed in closely related bacterial genomes, our results imply that the change of translation initiation mechanisms, which happens between the genes deriving from a common ancestor, is linearly dependent on the phylogenetic relationship. Analysis on the macroevolution of leaderless genes further shows that the proportion of leaderless genes in bacteria has a decreasing trend in evolution.As the first stage of protein synthesis in gene expression, translation is a key process highly conserved in the biological system. Up to now, 31 universally occurring genes identified in 191 species are shown being involved in the translation process [1]. However, translation initiation shows great variation in the three kingdoms. In eukaryotes, the ribosome binds at the 5'-end of the capped mRNA and slides downstream to find the first start codon and then initiate the translation, which is the so-called scanning mechanism [2]. In prokaryotes, there are two known mechanisms. The Shine-Dalgarno (SD) initiation mechanism was found early in Escherichia coli [3]. For this mechanism, a short motif called SD sequence in the 5'-untranslated region (5'-UTR) on mRNA binds with the
Theoretical analysis of the limiting rate of phreatic evaporation for aeolian sandy soil in Taklimakan Desert
ShunJun Hu,JiaQiang Lei,XinWen Xu,YuDong Song,ChangYan Tian,XiaoBin Chen,XiuChang Li
Chinese Science Bulletin , 2008, DOI: 10.1007/s11434-008-6014-3
Abstract: Phreatic evaporation is a great lose for shallow groundwater in the Taklimakan Desert. Given soil type and groundwater table, the limiting rate of phreatic evaporation is defined as the maximum of water transferred from groundwater to soil surface per unit time, which is a key parameter and control condition for phreatic evaporation model developing. The soil water characteristic curve for the aeolian sandy soil in the Taklimakan Desert was fitted with the least square method based on the formula of soil moisture characteristics curve proposed by Van Genuchten, using observed soil moisture and soil water suction data. The unsaturated hydraulic conductivity was determined by the instantaneous profile method in situ and the calculation formula for unsaturated hydraulic conductivity was established. According to the steady flow theory, the quasi-analytical solution of limiting rate of phreatic evaporation was derived on the basis of generalization of the formula of unsaturated hydraulic conductivity. The results show that the soil moisture characteristics in the Taklimakan Desert can be well described by Van Genuchten’s formula, and the limiting rate of phreatic evaporation declines by power function with the descending of groundwater table.
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