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In-situ Observation of Initiation and Propagation of Cleavage Microcrack in TiAl

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Journal of Materials Science & Technology 1995年第1期11卷 11-14页

作者： GAO, KW CHEN, qh Chu, WY HSIAO, CM

Nucleating and propagating of nanocrack formed in dislocation free zone (DFZ) for the brittle TiAl alloy has been studied through in-situ tensile test in TEM and analyzed using microfracture mechanics. The results show that a lot of dislocations can be emitted from a crack tip when the applied stress intensity K-la is larger than the stress intensity for dislocation emission K-le = 1.4 MPa . m(1/2) and a dislocation free zone, which sometimes is a close zone, can form after reaching equilibrium. The DFZ is a elastic zone with large strain and then the stress in the DFZ might equal to the cohesive strength sigma(th) because the crack tip is still sharp. When K-la is larger than the stress intensity for nanocrack nucleation K-li = 2.4 MPa . m(1/2), the stress within a certain range in the DFZ would equal to sigma(th) and then a nanocrack initiates in the DFZ or sometimes at the notch tip. The nanocrack formed in the DFZ is stable and can propagate a small distance in cleavage mode through multiplication and movement of dislocation in the plastic zone, during keeping constant displacement. Increasing K-la, can make the crack stably propagate continuously or discontinuously and it means that the stress intensify for crack propagation, K-lp, is larger than K-li. Therefore, K-le [K-li [K-lp [K-lC.

关键词： TiAl Figure DFZ

Synthesis of Novel Lipids Bearing Cholesteryl Group as Gene Vectors

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Chinese Chemical Letters 2000年第7期11卷 577-580页

作者： Zhu, MZ Wu, qh Wei, JN Zheng, XQ Guo, QX Univ Sci & Technol China Dept Chem Hefei 230026 Peoples R China

Some cationic and neutral lipids bearing cholesteryl group were synthesized as gene vectors, and the structures of the compounds were characterized by IR, (HNMR)-H-1, MS and elemental analysis.

关键词： cholesteryl derivatives gene vector lipid

DETERMINATION　OF　BORON　BY　MICROWAVE　PLASMA　TORCH　ATOMIC　EMISSION　SPECTROMETRY　USING　ON－LINE　SEPARATION　AND　PRECONCENTRATION　TECHNIQUE

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Chinese Chemical Letters 1996年第3期7卷 267-268页

作者： Jin, Q Zhang, HQ Liang, F Yang, WJ Jin, qh JILIN UNIV DEPT CHEMCHANGCHUN 130023PEOPLES R CHINA

in this paper boron was determined with on-line separation andpreconcentration technique by microwave plasma torch atomic emissionspectromeny (MPT-AES). Boron in steel samples was determined withsatisfactory results.

关键词： TORCH PLASMA MICROWAVE EMISSION ATOMIC AND LINE

A projective ternary phase diagram of stationary non-equilibrium states for low-pressure diamond growth

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Chinese Science Bulletin 1997年第11期42卷 967-968页

作者： Wang, JT huang, ZQ Wan, YZ Zhang, W Yang, qh Department of Electronic Engineering Fudan University Shanghai China Department of Applied Mathematics Tongji University Shanghai China

SINCE 1980,activated low-pressure diamond growth by chemical vapor deposition(CVD)pro-cess has been one of the worldwide interesting ***,in the last decades severalthermodynamic explanations were *** et *** a lot ofpu... 详细信息

关键词： A projective ternary phase diagram of stationary non-equilibrium states for low-pressure diamond growth

Biochemical mechanisms in drug-induced liver injury:Certainties and doubts

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World Journal of Gastroenterology 2009年第39期15卷 4865-4876页

作者： Ignazio Grattagliano Leonilde Bonfrate Catia V Diogo Helen H Wang David qh Wang Piero Portincasa Clinica Medica "A.Murri" Dipartimento di Medicina Interna e Medicina PubblicaUniversity of Bari Medical School Department of Zoology Center for Neurosciences and Cell BiologyUniversity of Coimbra Department of Medicine Liver Center and Gastroenterology DivisionBeth Israel Deaconess Medical CenterHarvard Medical School and Harvard Digestive Diseases Center

Drug-induced liver injury is a significant and still unresolved clinical problem. Limitations to knowledge about the mechanisms of toxicity render incomplete the detection of hepatotoxic potential during preclinical development. Several xenobiotics are lipophilic substances and their transformation into hydrophilic compounds by the cytochrome P-450 system results in production of toxic metabolites. Aging, preexisting liver disease, enzyme induction or inhibition, genetic variances, local 02 supply and, above all, the intrinsic molecular properties of the drug may affect this process. Necrotic death follows antioxidant consumption and oxidation of intracellular proteins, which determine increased permeability of mitochondrial membranes, loss of potential, decreased ATP synthesis, inhibition of Ca^2＋-dependent ATPase, reduced capability to sequester Ca^2＋ within mitochondria, and membrane bleb formation. Conversely, activation of nucleases and energetic participation of mitochondria are the main intracellular mechanisms that lead to apoptosis. Non-parenchymal hepatic cells are inducers of hepatocellular injury and targets for damage. Activation of the immune system promotes idiosyncratic reactions that result in hepatic necrosis or cholestasis, in which different HLA genotypes might play a major role. This review focuses on current knowledge of the mechanisms of drug-induced liver injury and recent advances on newly discovered mechanisms of liver damage. Future perspectives including new frontiers for research are discussed.

关键词： Adverse effects Apoptosis Drug toxicity Liver diseases Microsomes Mitochondria Necrosis

Evaluation of diameter dis-tribution of inside cavities of open CNTs by analyses of nitrogen cryo-adsorption isotherm

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Chinese Science Bulletin 2001年第15期46卷 1317-1320页

作者： Yang, qh Li, F Hou, PX Liu, C Liu, M Cheng, HM Chinese Acad Sci Inst Met Res Shenyang 110015 Peoples R China

Precise evaluation of innerdiameter distribution of open carbon nanotubes (CNTs) is the basis of systematic investigation of physico-chemical processes occurring in nano-sized quasi-1-dimensional carbons. Due to the porosity characteristics and adsorption properties, this study evaluated the innerdiameter and its distribution of carbon nanotubes by analyses of nitrogen cryo-adsorption isotherms, and proved that the gas adsorption method is an effective method to characterize the inner cavity structure in comparison with that of electron microscopy observations and Raman measurements. The advantages of this method are as follows: Firstly, statistical information for innerdiameter distribution of open nanotubes can be obtained; Secondly, the method based on the adsorption process in inner cavities is of importance for investigation of other physico-chemical pro- cesses inside the cavities of carbon nanotubes. And finally, if combining with other characterization methods, complete structural information

关键词： carbon nanotubes (CNTs) innerdiameter distribution gas adsorption method adsorption isotherm.

Applications of Pattern Recognition in Drug Discovery

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Chemical Research in Chinese Universities 2002年第2期18卷 107-108页

作者： W. Graham Richards Department of Chemistry, University of Oxford, Central Chemistry, South Parks Road, Oxford OX1 3qh, UK Department of Chemistry University of Oxford Central Chemistry South Parks Road 英国 Oxford

This is a brief account of the plenary talk given to the meeting of the Chinese Society of Chemical Science and Technology held in Oxford on 6 October 2001. The talk covered the application of pattern recognition techniques to discover molecules which will bind to the binding sites of proteins. Three situations were considered: the structure of the protein being unknown; the structure known but the binding site unknown; and finally, and this is the most important case for the future, both the structure and nature of the target site available in atomic detail. For this case we have developed a massively distributed computer program using a screensaver which now involves over one million personal computers, including over a thousand in China. The project will involve the screening of 3 5 billion small molecules against 16 protein targets, all of which are implicated in the process of cancer.

关键词： Pattern recognition Drug Protein Gene Binding site

Silybin counteracts lipid excess and oxidative stress in cultured steatotic hepatic cells

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World Journal of Gastroenterology 2016年第26期22卷 6016-6026页

作者： Giulia Vecchione Elena Grasselli Adriana Voci Francesca Baldini Ignazio Grattagliano David qh Wang Piero Portincasa Laura Vergani DISTAV Department of Earth Environment and Life Sciences University of Genova Department of Biomedical Sciences and human Oncology University School of Medicine Department of Internal Medicine Division of Gastroenterology and Hepatology Saint Louis University School of Medicine

AIM: To investigate in vitro the therapeutic effect and mechanisms of silybin in a cellular model of hepatic ***: Rat hepatoma FaO cells were loaded with lipids by exposure to 0.75 mmol/L oleate/palmitate for 3 h to mimic liver steatosis. Then, the steatotic cells were incubated for 24 h with different concentrations (25 to 100 μmol/L) of silybin as phytosome complex with vitamin E. The effects of silybin on lipid accumulation and metabolism, and on indices of oxidative stress were evaluated by absorption and fluorescence microscopy, quantitative real-time PCR, Western blot, spectrophotometric and fluorimetric ***: Lipid-loading resulted in intracellular triglyceride (TG) accumulation inside lipid droplets, whose number and size increased. TG accumulation was mediated by increased levels of peroxisome proliferator-activated receptors (PPARs) and sterol regulatory element-binding protein-1c (SREBP-1c). The lipid imbalance was associated with higher production of reactive oxygen species (ROS) resulting in increased lipid peroxidation, stimulation of catalase activity and activation of nuclear factor kappa-B (NF-κB). Incubation of steatotic cells with silybin 50 μmol/L significantly reduced TG accumulation likely by promoting lipid catabolism and by inhibiting lipogenic pathways, as suggested by the changes in carnitine palmitoyltransferase 1 (CPT-1), PPAR and SREBP-1c levels. The reduction in fat accumulation exerted by silybin in the steatotic cells was associated with the improvement of the oxidative imbalance caused by lipid excess as demonstrated by the reduction in ROS content, lipid peroxidation, catalase activity and NF-κB ***: We demonstrated the direct anti-steatotic and anti-oxidant effects of silybin in steatotic cells, thus elucidating at a cellular level the encouraging results demonstrated in clinical and animal studies.

关键词： Non-alcoholic fatty liver disease Steatotic hepatocytes Silybin Lipid metabolism Oxidative stress Lipid droplets Mitochondrial β -oxidation

BIOPOLYMER BASED NANO-DELIVERY SYSTEMS FOR ENHANCING BIOAVAILABILITY OF NUTRACEUTICALS

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Chinese Journal of Polymer Science 2013年第9期31卷 1190-1203页

作者： Bing hu Qing-rong huang College of Food Science and Technology Nanjing Agricultural University Department of Food Science Rutgers University

Recently, there has been an increasing interest in the development of efficient food-grade oral nano-delivery systems for encapsulation, protection and target delivery of nutraceuticals to enhance their bioavailability, fiarther to prevent disease and promote human health and well-being. Food proteins represent promising candidates for efficient nutraceutical nanocarriers due to their exceptional characteristics, namely biodegradability, nonantigenicity, high nutritional value, abundant renewable sources and extraordinary binding capacity to various nutraceuticals. In addition, their biocompatibility, biodegradability, low toxicity, low cost, and non-starch polysaccharides possess many favourable characteristics such as stability in the harsh gastric environment, resistance to digestive enzymes, and mucoadhesiveness to intestinal mucosal surface. This review describes the design and formation of nanoscaled delivery systems for nutraceuticals using food-grade proteins （including peptides）, polysaccharides and their associative complexes. The toxicity and cellular uptake fate of the nanostructures, as well as their effects on the intestinal absorption of the encapsulated nutraceuticals were also discussed.

关键词： Food biopolymer Nano-delivery systems Bioavailability Nutraceuticals.