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Articles by Qi Zhang
Total Records ( 12 ) for Qi Zhang
  Ying Xu , Tiejun Wang , Longlong Ma , Qi Zhang and Wei Liang
  The hydrotreatment of bio-oil, which obtained from fast pyrolysis of pine sawdust, was investigated over MoNi/γ-Al2O3 catalyst under mild conditions (373 K, 3 MPa hydrogen pressure). Acetic acid was taken as a model compound to investigate the effects of Mo promoter contents and reducing temperatures of catalysts on the catalysts activity under the condition of 473 K and 3 MPa hydrogen pressure. X-ray diffraction and temperature programmed reduction showed that the addition of Mo promoter benefited the uniformity of nickel species and inhibited the formation of NiAl2O4 spinel in the catalysts. The GC spectrum of liquid products showed the mechanism of the model reaction. The maximum conversion of acetic acid (33.20%) was attained over 0.06MoNi/γ-Al2O3 catalysts being reduced at 873 K. This catalyst was chosen for the upgrading of raw bio-oil. After the upgrading process, the pH value of the bio-oil increased from 2.33 to 2.77. The water content increased from 35.52 wt.% to 41.55 wt.% and the gross calorific value increased from 13.96 MJ/kg to 14.17 MJ/kg. The hydrogen content in the bio-oil increased from 6.25 wt.% to 6.95 wt.%. The product properties of the upgraded bio-oil, particularly the hydrogen content and the acidity were considerably improved. The results of gas chromatography–mass spectrometry analysis showed that both hydrotreatment and esterification had happened over 0.06MoNi/γ-Al2O3 (873) catalyst during the upgrading process.
  Qi Zhang , Guangji Wang , Jiye A , Bo Ma , Yu Dua , Lingling Zhu and Di Wu
  This study describes the metabolic profiles of the development of hyperlipidaemia in a rat model, utilizing metabonomics by gas chromatography–mass spectrometry (GC-MS) determination coupled with multivariate statistical analysis. Rat plasma samples were collected before and during a high-lipid diet at days 0, 7, 14, 21 and 28, and were analysed for lipid levels using kit assays or metabonomics using GC-MS. Forty-one endogenous metabolites were separated, identified and quantified using GC-MS. The data matrix was processed by principal component analysis or partial least squares discriminant analysis. Dynamic modification of the rat metabonome can be clearly identified and tracked at different stages of hyperlipidaemia in the rat model. Potential biomarkers, including β-hydroxybutyrate, tyrosine and creatinine, were identified. The current work suggests that metabonomics is able to provide an overview of biochemical profiles of disease progress in animal models. Using a metabonomic approach to identify physiopathological states promises to establish a new methodology for the early diagnosis of human diseases.
  Rui Tang , Qi Zhang and Shao Jiang Wang
  Pointing on uncertainties in the velocity servo system, caused by servo system can’t model accurately, may cause the deterioration of the control quality of the Electro-Hydraulic Velocity Servo System (EHVSS) and even lead to its instability. An Double Adaptive Fuzzy Sliding Mode Control (DAFSMC) algorithm is proposed for an EHVSS. The proposed control strategy has fast response and good disturbance rejection capability. The numerical simulation is presented to verify the effectiveness of the proposed control scheme. It is shown from the experimental results that the proposed controller offers several advantages such as fast response, good disturbance rejection capability, good velocity tracking capability and so forth. It is also revealed from simulation results that the proposed control strategy is valid for the EHVSS.
  Yu-Peng Ren , Xiao-Yu Wang , Qi-Gui Yan , Di-Shi Chen , Yu Cheng , Li Wan , Lei Ma , Qi Zhang , Lin Guo , Zhi-Yong Xie and Wan-Zhu Guo
  This study examined the recombinant Attenuated Salmonella Choleraesuis C500 containing M and N gene of PEDV whether can induce a systemic immune responses in mice. After identified by enzyme analysis and nucleotide sequencing test, the constructed recombinant plasmid, designated as pIRES-M-N was transfected into Vero cells. The transient expression protein was detected by indirect Immunofluorescence Assay (IFA) and Western-blotting. Result showed that pIRES-M-N can be expressed correctly in Vero cells. Then, the recombinant plasmid electroporated into S. choleraesuis C500 and the recombinant bacteria was proved to be stabile in vitro. The immunogenicities of this recombinant attenuated salmonella constructs were firstly investigated in a mouse mode. Specific anti-PEDV IgG antibodies and IFN-γ, IL-4 of cytokine were detected. The result showed that the recombinant Attenuated Salmonella could induce higher persistence specific hummune responses in mouse by contrast with naked DNA group after 42 days (p<0.05). It also, stimulated a balanced Th1/Th2 immune response. That provided the clinical basic data and theoretical basis for success of the attenuated salmonella vaccine development.
  Jie Fang , Yiping Zhang , Lijuan Huang , Xinying Jia , Qi Zhang , Xu Zhang , Gongli Tang and Wen Liu
  Tetrocarcin A (TCA), produced by Micromonospora chalcea NRRL 11289, is a spirotetronate antibiotic with potent antitumor activity and versatile modes of action. In this study, the biosynthetic gene cluster of TCA was cloned and localized to a 108-kb contiguous DNA region. In silico sequence analysis revealed 36 putative genes that constitute this cluster (including 11 for unusual sugar biosynthesis, 13 for aglycone formation, and 4 for glycosylations) and allowed us to propose the biosynthetic pathway of TCA. The formation of D-tetronitrose, L-amicetose, and L-digitoxose may begin with D-glucose-1-phosphate, share early enzymatic steps, and branch into different pathways by competitive actions of specific enzymes. Tetronolide biosynthesis involves the incorporation of a 3-C unit with a polyketide intermediate to form the characteristic spirotetronate moiety and trans-decalin system. Further substitution of tetronolide with five deoxysugars (one being a deoxynitrosugar) was likely due to the activities of four glycosyltransferases. In vitro characterization of the first enzymatic step by utilization of 1,3-biphosphoglycerate as the substrate and in vivo cross-complementation of the bifunctional fused gene tcaD3 (with the functions of chlD3 and chlD4) to ΔchlD3 and ΔchlD4 in chlorothricin biosynthesis supported the highly conserved tetronate biosynthetic strategy in the spirotetronate family. Deletion of a large DNA fragment encoding polyketide synthases resulted in a non-TCA-producing strain, providing a clear background for the identification of novel analogs. These findings provide insights into spirotetronate biosynthesis and demonstrate that combinatorial-biosynthesis methods can be applied to the TCA biosynthetic machinery to generate structural diversity.
  Qi Zhang , Linhong Wang , Yan Jiang , Liwen Fang , Pinliang Pan , Shuangyan Gong , Jun Yao , Yi-Wei Tang , Sten H. Vermund and Yujiang Jia
  The early detection of human immunodeficiency virus type 1 (HIV-1) infection in infants is complicated by the persistence of maternal antibodies and by diverse HIV-1 subtypes. We developed a nested, three-monoplex HIV-1 DNA PCR (N3M-PCR) assay to detect diverse HIV-1 subtypes in infants born to infected mothers. We optimized the test for use with dried blood spot (DBS) samples for ease of storage and transport from rural China to central laboratories. Six pairs of primers were designed that targeted env, gag, and pol genes, and the test was run in three reactions with an analytical sensitivity of 10 copies DNA per reaction to cover nine HIV-1 subtypes, A, B, C, D, F, G, CRF01-AE, CRF08-BC, and CRF07-BC. The assay performance was evaluated on 347 DBS specimens from 151 exposed infants in four diverse provinces of China in which multiple subtypes were circulating. The results of this test were compared to those of HIV antibody enzyme immunoassay and Western blotting confirmation for the infants at >=18 months of age or to convincing clinical and epidemiologic data for deceased infants. The sensitivity of the N3M-PCR assay was 30.0% (3/10) for infants at 48 h after birth, 91.7% (11/12) at 1 to 2 months of age, and 93.7% (15/16) at 3 to 6 months of age. The specificity was 100% (94/94) at all three time points. The PCR reproducibility in the three DNA regions was 100% for samples at 48 h after birth, 96.7% at 1 to 2 months, and 100% at 3 to 6 months of age. The HIV-1 DNA N3M-PCR assay on DBSs offers a simple and affordable approach for early infant HIV-1 diagnosis in regions with diverse HIV-1 circulating subtypes.
  Qi Zhang , Meifang Zhu , Qinghong Zhang , Yaogang Li and Hongzhi Wang
  Mn1−xZnxFe2O4 nanospheres were self-assembled alongside the multi-walled carbon nanotubes (MWCNTs) via solvothermal method. The shape, structure, and size of the as-synthesized sample were characterized by X-ray diffraction pattern (XRD), transmission electron microscope (TEM), scanning electron microscopy (SEM) and vibrating sample magnetometry (VSM). The results shown that a large number of the high purity Mn1−xZnxFe2O4 nanocrystallites were decorated on the sidewalls of the MWCNTs, and these nanocrystallites aggregated around the MWCNTs templates formed spherical aggregation. The maximum magnetic saturation value of the Mn1−xZnxFe2O4/MWCNTs nanocomposites reached 55.6 emu g−1. The probable formation mechanism of the nanocomposites was also investigated based on the experimental results.
  Qi Zhang , Gui Weihua and Yirong Liu
  In this paper, center conditions and bifurcation of limit cycles from the equator for a class of polynomial system of degree seven are studied. The method is based on converting a real system into a complex system. The recursion formula for the computation of singular point quantities of complex system at the infinity, and the relation of singular point quantities of complex system at the infinity with the focal values of its concomitant system at the infinity are given. Using the computer algebra system Mathematica, the first 14 singular point quantities of complex system at the infinity are deduced. At the same time, the conditions for the infinity of a real system to be a center and 14 order fine focus are derived respectively. A system of degree seven that bifurcates 13 limit cycles from the infinity is constructed for the first time.
  Hai-Jun Zuo , Qi Zhang , Lu-Yi Ma , Heike Hartmann , Jian-Qing Zhai and Li-Gang Xu
  Soil water plays an important role in the process of formation, transformation and consumption of water resources and its quantity and existing form is closely related to the growth and development of crops. As for plants, soil water use efficiency is to a large extent constrained by soil water content and storage which are affected by many factors in different degree. Among them, soil water percolation is one of the main reasons to cause soil water loss. Previous research indicated that percolation loss is one of the most important ways of water and nutrients loss from agricultural soil. In most cases, natural rainfall and unrational irrigation easily lead to soil water percolation loss. In order to understand the response of soil water percolation to different rainfall conditions for subsequent assessment of associated nitrogen loss, a numerical model has been used to simulate the soil water percolation rates under different rainfall scenarios in this study. Results indicated that soil water percolation rate was highly correlated to the rainfall intensity. For the same total amount of rainfall in a certain time period, the total amount of soil water percolation for rainfall events of low frequency and high intensity was greater than that for rainfall events of high frequency and low intensity. On the other hand, the percolation rate was relevant to the preceding rainfall events. Multiple rainfall events in a relatively short period will result in a peak percolation rate.
  Liu Yang , Jeremiah M. Clinton , Michael L. Blackburn , Qi Zhang , Junhui Zou , Anna Zielinska-Kwiatkowska , Bor Luen Tang and Howard A. Chansky
  Insulin treatment of mouse ATDC5 chondroprogenitors induces these cells to differentiate into mature chondrocytes. To identify novel factors that are involved in this process, we carried out mutagenesis of ATDC5 cells through retroviral insertion and isolated two mutant clones incapable of differentiation. Inverse PCR analysis of these clones revealed that the retroviral DNA was inserted into the promoter region of the Rab23 gene, resulting in increased Rab23 expression. To investigate whether an elevated level of Rab23 protein led to inhibition of chondrogenic differentiation, we characterized ATDC5 cells that either overexpress endogenous Rab23 or stably express ectopic Rab23. Our results revealed that up-regulation of Rab23 can indeed inhibit chondrogenic differentiation with a concomitant down-regulation of matrix genes such as type II collagen and aggrecan. In addition, stable small interfering RNA knockdown of Rab23 also resulted in inhibition of chondrogenic differentiation as well as down-regulation of Sox9, a master regulator of chondrogenesis. Interestingly, Sox9 expression has recently been linked to Gli1, and we found that Rab23 knockdown decreased Gli1 expression in chondrocytes. Because the phenotypes of Rab23 mutations in mice and humans include defects in cartilage and bone development, our study suggests that Rab23 is involved in the control of Sox9 expression via Gli1 protein.
  Tobias Stumpf , Qi Zhang , Daniela Hirnet , Urs Lewandrowski , Albert Sickmann , Ulrich Wissenbach , Janka Dorr , Christian Lohr , Joachim W. Deitmer and Claudia Fecher-Trost
  Transcellular calcium transport in the kidney, pancreas, small intestine, and placenta is partly mediated by transient receptor potential (TRP) channels. The highly selective TRPV6 calcium channel protein is most likely important for the calcium transfer in different specialized epithelial cells. In the human placenta the protein is expressed in trophoblast tissue, where it is implicated in the transepithelial calcium transfer from mother to the fetus. We enriched the TRPV6 channel protein endogenously expressed in placenta together with annexin A2 and cyclophilin B (CypB), which is a member of the huge immunophilin family. In the human placenta TRPV6 and CypB are mainly located intracellularly in the syncytiotrophoblast layer, but a small amount of the mature glycosylated TRPV6 channel protein and CypB is also expressed in microvilli apical membranes, the fetomaternal barrier. To understand the role of CypB on the TRPV6 channel function, we evaluated the effect of CypB co-expression on TRPV6-mediated calcium uptake into Xenopus laevis oocytes expressing TRPV6. A significant increase of TRPV6-mediated calcium uptake was observed after CypB/TRPV6 co-expression. This stimulatory effect of CypB was reversed by the immunosuppressive drug cyclosporin A, which inhibits the enzymatic activity of CypB. Cyclosporin A had no significant effect on TRPV6 and CypB protein expression levels in the oocytes. In summary, our results establish CypB as a new TRPV6 accessory protein with potential involvement in TRPV6 channel activation through its peptidyl-prolyl cis/trans isomerase activity.
  Jianying Huang , Aijie Huang , Qi Zhang , Yen- Chang Lin and Han- Gang Yu
  We have previously reported an important role of increased tyrosine phosphorylation activity by Src in the modulation of hyperpolarization-activated cyclic nucleotide-gated (HCN) channels. Here we provide evidence showing a novel mechanism of decreased tyrosine phosphorylation on HCN channel properties. We found that the receptor-like protein-tyrosine phosphatase-α (RPTPα) significantly inhibited or eliminated HCN2 channel expression in HEK293 cells. Biochemical evidence showed that the surface expression of HCN2 was remarkably reduced by RPTPα, which was in parallel to the decreased tyrosine phosphorylation of the channel protein. Confocal imaging confirmed that the membrane surface distribution of the HCN2 channel was inhibited by RPTPα. Moreover, we detected the presence of RPTPα proteins in cardiac ventricles with expression levels changed during development. Inhibition of tyrosine phosphatase activity by phenylarsine oxide or sodium orthovanadate shifted ventricular hyperpolarization-activated current (If, generated by HCN channels) activation from nonphysiological voltages into physiological voltages associated with accelerated activation kinetics. In conclusion, we showed a critical role RPTPα plays in HCN channel function via tyrosine dephosphorylation. These findings are also important to neurons where HCN and RPTPα are richly expressed.
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