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Search Results: 1 - 10 of 112823 matches for " Zhi-Hua Chen "
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Two faces of lipid peroxidation products: the -Yin and Yang- principles of oxidative stress
Zhi-Hua Chen,Etsuo Niki
Journal of Experimental and Integrative Medicine , 2011,
Abstract: Oxidants and antioxidants, like many other things, have two faces. Lipids, important biological substances of aerobic organisms, are oxidized by reactive oxygen and nitrogen species formed inevitably in vivo to give diverse products. The emerging evidence suggests that lipid peroxidation products have also two faces. Lipid peroxidation products alter biological membrane organization and modify proteins and nucleic acids, which result in a number of dysfunctional states in vivo. Many studies show that the levels of lipid peroxidation products increase with the development of acute and chronic diseases. Lipid peroxidation products may modulate signal transduction pathways and mediate biological processes through receptors or receptor-independent pathways. At the same time, it has been shown that the lipid peroxidation products induce adaptive response and increase tolerance against forthcoming oxidative stress by upregulating defense capacity. In this brief review, the examples of such dual opposite effects of lipid peroxidation products are shown and the underlying mechanisms are suggested. [J Exp Integr Med 2011; 1(4.000): 215-219]
Generating Entangled States of Multilevel Atoms through a Selective Atom-Field Interaction

CHEN Zhi-Hua,LIN Xiu-Min,

中国物理快报 , 2011,
Entropy-Inspired Competitive Clustering Algorithms

Daoqiang Zhang,Songcan Chen,Zhi-Hua Zhou,

软件学报 , 2007,
Abstract: In this paper, the well-known competitive clustering algorithm (CA) is revisited and reformulated from a point of view of entropy minimization. That is, the second term of the objective function in CA can be seen as quadratic or second-order entropy. Along this novel explanation, two generalized competitive clustering algorithms inspired by Renyi entropy and Shannon entropy, i.e. RECA and SECA, are respectively proposed in this paper.Simulation results show that CA requires a large number of initial clusters to obtain the right number of clusters, while RECA and SECA require small and moderate number of initial clusters respectively. Also the iteration steps in RECA and SECA are less than that of CA.Further CA and RECA are generalized to CA-p and RECA-p by using the p-order entropy and Renyi's p-order entropy in CA and RECA respectively. Simulation results show that the value of phas a great impact on the performance of CA-p, whereas it has little in uence on that of RECA-p.
Diplexers Based on Microstrip Line Resonators with Loaded Elements
Jin Shi;Jian-Xin Chen;Zhi-Hua Bao
PIER , 2011, DOI: 10.2528/PIER11031516
Abstract: In this paper, microstrip line resonators with loaded elements are proposed and studied to design microstrip diplexer. To demonstrate the design ideas, the equivalent circuits of the proposed resonators are built and studied. It is found that the different loads on different positions of the proposed half-wavelength resonator make the resonator have different features, which will easily control the characteristic of the diplexers. And here, resistor, open stub, and shorted stub are used as loaded elements. It is found the resistor loaded on the center of the microstrip line resonator can extremely reduce the unloaded quality factor of even-mode resonant frequency, which can be used to suppress the harmonics of the diplexer. The loaded open stub not only can reduce the size of the diplexer, but also can control the frequency ratio between the fundamental frequency and second harmonic of a resonator, which can increases the frequency ratio between the two passbands of the diplexer. As for the loaded shorted stub, it can enlarge the size of the diplexer. To demonstrate the design ideas, three diplexers are presented. The comparisons between the loaded and unloaded diplexers are given. The experimental results agree well to the theoretical predictions and simulations.
The mechanism of ligand-independent activation of estrogen receptor in letrozole-resistant breast cancer cells
Hong-yan CHEN,Zhi-hua LIU
Medical Journal of Chinese People's Liberation Army , 2013,
Abstract: Objective To investigate the functions and mechanisms of transcriptional regulation changes in estrogen receptor (ER) on letrozole resistance in breast cancer cells. Methods Letrozole resistant cells (MCF-7-LR-1 and MCF-7 LR-2) and control cells (MCF-7-Aro and MCF-7-T) were used in present study. The levels of ER phosphorylation at Ser-118 and expressions of ER in these two groups were determined by Western blotting. The conjugation of ER with XBP-1 enhancer and TFF-1 promoter with or without β-Estradiol (E2) was detected by Chromatin Immuno-coprecipitation (ChIP) assay. The mRNA expression levels of XBP-1 and TFF-1 were determined by quantitative reverse transcription PCR (qRT-PCR) analysis. Furthermore, the mRNA expressions of estrogen responsive genes (ERGs) including CA2, GJA1, PGR, and CTSD were assayed also by qRT-PCR analysis. Results The level of ER phosphorylation at Ser-118 significantly increased in MCF-7-LR cells than in control cells. However, the ER expression showed no significant change. ChIP assay demonstrated that, under ligand-independent (without E2 treatment) or ligand-dependent (with E2 treatment 10nmol/L E2 treatment for 45min) condition, the conjugation of ER with XBP 1 enhancer and TFF-1 promoter significantly increased in MCF-7-LR-2 cells than in control cells. qRT-PCR analysis showed that the mRNA expressions of XBP-1 and TFF-1 increased in MCF-7-LR-2 cells compared with those in MCF-7-Aro cells without E2 treatment. Furthermore, the mRNA expressions of CA2 and GJA1 increased, whereas the mRNA expressions of PGR and CTSD decreased in MCF-7-LR-2 cells versus MCF-7-T cells. Conclusion The level of ER phosphorylation at Ser-118 increased in a ligand-independent manner, thereby promoting the transcription of target genes in letrozole resistant breast cancer cells, and it plays an important role in letrozole resistance.
Super fidelity and related metric
Zhi-Hao Ma,Fu-Lin Zhang,Zhi-Hua Chen,Jing-Ling Chen
Physics , 2008,
Abstract: We report a new metric of quantum states. This metric is build up from super-fidelity, which has deep connection with the Uhlmann-Jozsa fidelity and plays an important role in quantifying entanglement. We find that the new metric possess some interesting properties.
Isoprenoid Biosynthesis in Plants: Pathways, Genes, Regulation and Metabolic Engineering
Zhi-Hua Liao,Min Chen,Yi-Fu Gong,Zhi-Qi Miao
Journal of Biological Sciences , 2006,
Abstract: Isoprenoids, namely terpenoids, are the largest and the most structurally varied groups of natural products, which contain more than 30,000 known compounds. All the isoprenoids are biosynthesized from only two C5 precursors in plants, isopentenyl diphosphate and its isomer, dimethylallyl diphosphate. Two distinct pathways of isopentenyl diphosphate biosynthesis exist in plants: the classical mevalonate pathway and the recently unveiled deoxyxylulose 5-phosphate pathway. In this study, we summarize the recent progress on the molecular genetics of the two pathways, specializing in pathways, genes, enzymes, intermediates, subcellular compartments of isoprenoid biosynthesis, crosstalk of the two pathways and metabolic regulation and engineering.
An integrated predictive iterative learning control for batch process

CHEN Chen,XIONG Zhi-hua,

控制理论与应用 , 2012,
Abstract: In order to improve the convergence speed of iterative learning control (ILC), an integrated scheme for tracking problem of batch process is proposed by combining batch-to-batch P-type ILC and within-batch model predictive control (MPC). Based on a predefined batch-wise linear model of the process, the output of traditional P-type ILC can be predicted, and then MPC is induced to minimize a quadratic objective function within the current batch. The input is updated within the batch so that the output may approach the reference trajectory faster. An illustrative example is presented to demonstrate the performance of the proposed scheme.
Studies on the Polypropylene Composites Reinforced by Ramier Fiber and Whisker
Chun-Guang Long,Li-Ping He,Zhi-Hua Zhong,Shu-Guang Chen
Advances in Materials Science and Engineering , 2007, DOI: 10.1155/2007/87072
Abstract: Polypropylene composites reinforced by the ramier fiber and K2Ti6O13 whisker were successfully prepared by means of the torque rheometer blending and transfer molding. Their mechanical properties were tested, and the fracture surface of the composite was analysed by SEM technique. Results showed that the mechanical properties were improved by the addition of 10% of K2Ti6O13 whisker besides the impact strength. The RF is benefit for improving the mechanical properties of PP after being surface-treated properly.
Structure and Properties of - Nanocomposite Films for Biomedical Applications
Lin Zhang,Zhi-Hua Sun,Feng-Mei Yu,Hong-Bin Chen
Bioinorganic Chemistry and Applications , 2011, DOI: 10.1155/2011/853048
Abstract: The hemocompatibility of La2O3-doped TiO2 films with different concentration prepared by radio frequency (RF) sputtering was studied. The microstructures and blood compatibility of TiO2 films were investigated by scan electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), and UV-visible optical absorption spectroscopy, respectively. With the increasing of the La2O3 concentrations, the TiO2 films become smooth, and the grain size becomes smaller. Meanwhile, the band gap of the samples increases from 2.85 to 3.3?eV with increasing of the La2O3 content in TiO2 films from 0 to 3.64%. La2O3-doped TiO2 films exhibit n-type semiconductor properties due to the existence of Ti2+ and Ti3+. The mechanism of hemocompatibility of TiO2 film doped with La2O3 was analyzed and discussed. 1. Introduction With the advancement of organ transplantation, biocompatibility, particularly blood compatibility, becomes the most important property required for biomedical materials. It is desired to develop new biomaterials with good physical, mechanical properties and hemocompatibility. Recent studies have shown that TiO2 films are suitable as surface coatings on biomedical applications due to its good hemocompatibility [1, 2], and researches concerning biomedical aspects are widely increasing [3–5]. The emphases of blood compatible materials research are divided into two aspects, one is the surface properties, and the other is the band and electron structure of the biomedical materials. It is believed that the first step after blood contacting with the biomaterial is adsorption of plasma protein, which will determine the anticoagulation property of the biomaterial. In our previous paper [6], we studied the surface properties of La2O3-doped TiO2 films and investigated the interaction between the material surface and plasma proteins. In this paper, we do the farther work and try to achieve deeper understanding of the mechanisms which are involved in blood-biomaterial interaction by investigating the influence of various La2O3 concentrations on the electronic structure and hemocompatibility of TiO2 nanocomposite films. 2. Materials and Methods 2.1. Preparation of Thin Films The La2O3-doped TiO2 films were prepared by the radio frequency (13.56?MHz) magnetron sputtering technique. The n-type Si (100) and quartz were used as the substrates. The targets were mechanically mixed by using TiO2 powder (in purity 99.9%) and La2O3 powder (in purity 99.5%) with the La2O3 molar concentration of 0%, 1%, 2%, and 3%, respectively. The substrates were ultrasonically cleaned in acetone
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