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Influence of pH, Heat and Enzymatic Treatments on the Activity of Antibacterial Substance in MRS and Milk Media Produced by Lactobacillus fermentum F6

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Agricultural Sciences in China 2010年第6期9卷 911-920页

作者： zhang Yong LIU Yong BAO yan zhang He-ping Key Laboratory of Dairy Biotechnology and Engineering Ministry of Education/Department of Food Science and Engineering InnerMongolia Agricultural University Hohhot 010018 P.R. China

This study aimed to investigate the influence of pH,heat and enzymatic treatments on the activity of antibacterial substance in MRS,skim soy milk and bovine milk media fermented by a potential probiotic Lactobacillus fermentum *** antibacterial activity of the culture supernatant of *** F6 was tested against a wide range of Gram-positive and Gram-negative pathogenic bacteria including Staphylococcus aureus,Escherichia coli,Listeria monocytogenes,Salmonella typhimurium,and Shigella *** antibacterial activities were detected in MRS and milk but not in soy *** presumed that three kinds of probable components including organic acids,heat-stable and heat-labile proteinaceous compounds were involved in antibacterial activity of fermented MRS and *** influence of acids on antibacterial activity was pH-dependent and this effect multiplied with thermal treatments seemed *** analyses showed various significant differences of antibacterial activity among five pathogens were observed in pH and heat *** untreated fermented milk showed higher inhibitory activity to Gram-positive pathogenic bacteria than Gram-negative bacteria （P 〈 0.05）,indicating antibacterial substances of fermented milk are greatly different from fermented *** accurate stimulated gastrointestinal transit showed antibacterial substances would have no influence on intestinal *** range of antibacterial substances from pH 2.0 to 6.0 can be potentially used as food biopreservatives and alternative therapeutics.

关键词： Lactobacillusfermentum F6 antibacterial activity pH thermal treatments enzymatic effect

Time-Dependent Density-Functional Calculations for Optical Spectra of Na2 and Na4 Clusters

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Communications in Theoretical Physics 2007年第5期47卷 901-904页

作者： zhang yan-ping zhang Feng-Shou MENG Ke-Lai XIAO Guo-Qing Center of Theoretical Nuclear Physics National Laboratory of Heavy Ion Accelerator of Lanzhou Lanzhou 730000 China Institute of Modern Physics the Chinese Academy of Sciences Lanzhou 730000 China Institute of Low Energy Nuclear Physics Beijing Normal University Beijing 100875 China Graduate School of the Chinese Academy of Sciences Beijing 100049 China

With the frame of the time-dependent local density approximation, an efficient description of the optical response of clusters has been used to study the photo-absorption cross section of Na2 and Na4 clusters. It is shown that our calculated results are in good agreement with the experiment. In addition, our calculated spectrum for the Na4 cluster is in better agreement with experiment than the GW absorption spectrum.

关键词： time-dependent local density approximation optical response of cluster

An Approach to Enhance the Efficiency of a Brownian Heat Engine

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Chinese Physics Letters 2011年第10期28卷 40-43页

作者： zhang yan-ping HE Ji-Zhou XIAO Yu-Ling Department of Physics Nanchang UniversityNanchang 330031

A Brownian microscopic heat engine,driven by temperature difference and consisting of a Brownian particle moving in a sawtooth potential with an external load,is *** heat flows,driven by both potential and kinetic energies,are taken into *** on the master equation,the expressions for efficiency and power output are derived analytically,and performance characteristic curves are *** is shown that the heat flow via the kinetic energy of the particle *** efficiency of the engine is enhanced,but the power output reduces as theαshape parameter of the sawtooth potential *** influence of theαshape parameter on efficiency and power output is then analyzed in detail.

关键词： Brownian potential parameter

Resolution and Crystal Structure of 9α-(3-Azabicyclo[3,3,1]nonanyl)- 2′-cyclopentyl-2′-hydroxyl-2′-thienylacetate

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Chinese Journal of Structural Chemistry 2006年第5期25卷 547-551页

作者： LIU He HAN Xiang-Yu zhang yan-ping ZHONG Bo-Hua LIU Ke-Liang Beijing Institute of Pharmacology and Toxicology 27 Taiping Road Beijing 100850 China

The crystal structure of 9α-（3-azabicyclo[3,3,1]nonanyl）-2′-cyclopentyl-2′-hydro- xyl-2′-thienylacetate （C16H27NO3S, Mr = 349.48） has been determined by single-crystal X-ray diffraction analysis. The crystal belongs to orthorhombic, space group P212121 with a = 14.937（3）, b = 8.1673（16）, c = 15.423（3） ,A, V = 1881.5（6） ,A^3, Z = 4, Dc =1.234 g/cm^3, μ = 0.188 mm^-1, F（000） = 752, the final R = 0.0468 and wR = 0.1251. The bicyclo[3,3,1]nonane ring system adopts the most favored twin-chair conformation. The crystal structure shows the existence of intramolecular O-H…O hydrogen bonds by which a one-dimensional chain structure is formed.

关键词： optical resolution crystal structure muscarinic receptor antagonist

Influence of education and working background on physicians' knowledge of secondary prevention guidelines for coronary heart disease: results from a survey in China

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2012年第3期13卷 231-238页

作者： yan-jun GONG Tao HONG Jie JIANG Rong-hui YU yan zhang Zhao-ping LIU Yong HUO Department of Cardiology Peking University First Hospital Beijing 100034 China

Background and objective： In clinical practice, the standard of secondary prevention for coronary heart disease （CHD） is quite disappointing in China. The physicians＇ shortage of knowledge of secondary prevention guidelines is thought to be a key factor contributing to the inadequate and delayed translation of guidelines into clinical practice. The purpose of this study is to investigate the influence of physicians＇ characteristics, including their educa- tion and work experience, on their knowledge of secondary prevention in China. Methods： A representative ques- tionnaire survey was made of physicians from cardiology departments in 35 tertiary hospitals in China. The survey contained 19 questions on knowledge of guideline recommendations for the secondary prevention of CHD. We col- lected basic information about the physicians, including their educational degree, clinical practice duration/work experience and geographic region. Results： In total, 864 physicians participated in the survey. Eight hundred and thirty-seven completed questionnaires were analyzed. For 6 of the 19 questions, physicians with a postgraduate degree were more likely to answer correctly than those without such a degree. For 11 of the 19 questions, physicians with more than three years＇ clinical experience were more likely to answer correctly than those who had less than three years＇ experience. For 5 of the 19 questions, *** eastern areas were more likely to answer correctly than those from mid/western areas. The mean total score of correct answers to the questionnaire was 11.69 points. Edu- cational degree and clinical practice duration affected total scores significantly while practice location did not （β=0.500, P=0.004; ,β=0.979, P=0.000; and 8=0.228, P=0.162, respectively）. Even if a relatively low score of 12 is taken as a threshold level of acceptable knowledge （defined as a pass）, the pass rate of all physicians was only 53.9%. Educational degree and clinical practice durat

关键词： Coronary heart disease Secondary prevention Guidelines Survey

A Dynamic-Bayesian-Networks-Based Resilience Assessment Approach of Structure Systems: Subsea Oil and Gas Pipelines as A Case Study

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China Ocean Engineering 2020年第5期34卷 597-607页

作者： CAI Bao-ping zhang yan-ping YUAN Xiao-bing GAO Chun-tan LIU Yong-hong CHEN Guo-ming LIU Zeng-kai JI Ren-jie National Engineering Laboratory of Offshore Geophysical and Exploration Equipment China University of PetroleumQingdao 266580China College of Mechanical and Electronic Engineering China University of PetroleumQingdao 266580China

Under unanticipated natural disasters, any failure of structure components may cause the crash of an entire structure system. Resilience is an important metric for the structure system. Although many resilience metrics and assessment approaches are proposed for engineering system, they are not suitable for complex structure systems, since the failure mechanisms of them are different under the influences of natural disasters. This paper proposes a novel resilience assessment metric for structure system from a macroscopic perspective, named structure resilience, and develops a corresponding assessment approach based on remaining useful life of key components. Dynamic Bayesian networks(DBNs) and Markov are applied to establish the resilience assessment model. In the degradation process, natural degradation and accelerated degradation are modelled by using Bayesian networks, and then coupled by using DBNs. In the recovery process, the model is established by combining Markov and DBNs. Subsea oil and gas pipelines are adopted to demonstrate the application of the proposed structure metric and assessment approach.

关键词： structure resilience structure system remaining useful life dynamic Bayesian networks

Short-Term Responses of Nitrogen Mineralization and Microbial Community to Moisture Regimes in Greenhouse Vegetable Soils

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Pedosphere 2012年第2期22卷 263-272页

作者： CHEN Qiu-Hui FENG Ying zhang yan-ping zhang Qi-Chun I.H.SHAMSI zhang Yong-Song LIN Xian-Yong Key Laboratory of Environmental Remediation and Ecosystem Health of Ministry of Education College of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058(China) Key Laboratory of Subtropical Soil Science and Plant Nutrition of Zhejiang Province College of Environmental and Resource SciencesZhejiang UniversityHangzhou 310058(China)

Soil drying and wetting impose significant influences on soil nitrogen (N) dynamics and microbial communities. However, effects of drying-wetting cycles, while common in vegetable soils, especially under greenhouse conditions, have not been well studied. In this study, two greenhouse vegetable soils, which were collected from Xinji (XJ) and Hangzhou (HZ), China, were maintained at 30% and 75% water-holding capacity (WHC), or five cycles of 75% WHC followed by a 7-day dry-down to 30% WHC (DW). Soil inorganic N content increased during incubation. Net N mineralization (Nmin), microbial activity, and microbial biomass were significantly higher in the DW treatment than in the 30% and 75% WHC treatments. The higher water content (75% WHC) treatment had higher Nmin, microbial activity, and microbial biomass than the lower water content treatment (30% WHC). Multivariate analyses of community-level physiological profile (CLPP) and phospholipid fatty acid (PLFA) data indicated that soil moisture regime had a significant effect on soil microbial community substrate utilization pattern and microbial community composition. The significant positive correlation between Nmin and microbial substrate utilization or PLFAs suggested that soil N mineralization had a close relationship with microbial community.

关键词： drying-wetting cycles microbial activity microbial biomass microbial substrate utilization phospholipid fatty acid

Effects of the crude extract of Polygala tenuifolia Willd on human sperm in vitro

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2011年第6期12卷 448-454页

作者： Yi QIU Lei-guang WANG Yi-fang JIA Dan-tong yanG Mei-hua zhang yan-ping zhang Li-hong zhang Ling GAI Key Laboratory for Improving Birth Outcome Technique Shandong Provincial Institute of Science and Technology for Family Planning Jinan 250002 China

The aim of the present study is to analyze sperm membrane changes and the spermicidal effect in treatment with the crude extract from Polygala tenuifo/ia Willd （PTW） in vitro. The root of PTW was extracted in distilled water. Normal human spermatozoa were used to assess the spermicidal activity （Sander-Cramer assay） of the extract from the PTW root. The hypo-osmotic swelling （HOS） test and the eosin Y （EY） staining were used to detect the integrity of sperm membrane and vitality. The sperm chromatin dispersion （SCD） test was performed to determine sperm DNA integrity. N-9 was used as a reference standard and semen added to physiological saline was used as the control. Semen samples were donated by 42 healthy fertile men. The crude extract from the root of PTW could immobilize and kill 100% spermatozoa within 20 s in vitro at the concentrations of 20.0 and 10.0 mg/ml; at the concentration of 5.0 mg/ml, spermatozoa were immobilized in （39.5±3.2） s. In the groups of the crude extract from the root of PTW and N-9 solution the rate of the normal HOS （tails swollen） and the white head （unstained） was 0%, and the rate of the abnormal HOS （tails unswollen） and red head （stained） was 100%. Sperm DNA fragmentation showed no change in exposure to the crude extract from the root of PTW and N-9 solution. The sperm revival test did not show any spermatozoa that recovered their motilities. The rapid spermicidal activity of the crude extract from the root of PTW in vitro may occur by the disruption of the sperm membrane integrity.

关键词： Polygala tenuifofia Willd Crude extract Spermicidal effect in vitro Sperm membrane DNA integrity

Photosynthetic Characteristics and Antioxidative Metabolism of Flag Leaves in Responses to Nitrogen Application During Grain Filling of Field-Grown Wheat

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Agricultural Sciences in China 2008年第2期7卷 157-167页

作者： CAI Rui-guo zhang Min YIN yan-ping WANG ping zhang Ti-bin GU Feng DAI Zhong-min LIANG Tai-bo WU Yun-hai WANG Zhen-lin State Key Laboratory of Crop Biology/Agronomy College Shandong Agricultural University/Key Laboratory of Wheat Cultivation Physiology and Genetic Improvement Ministry of Agriculture Tai＇an 271018 PR.China

A two-factorial experiment was conducted with two wheat cultivars, SN1391 （large spike and large grain） and GC8901 （multiple spike and medium grain）, and two nitrogen （N） application rates （12 and 24 g N m^-2）, to investigate the responses of photosynthetic characteristics and antioxidative metabolism to nitrogen rates in flag leaves of field-grown wheat during grain filling. The results showed that the content of N and chlorophyll （Chl） in wheat flag leaves decreased after anthesis and the net photosynthetic rate （Pn）, effective quantum yield of PS Ⅱ （Фps n）, efficiency of excitation capture by open PS Ⅱ reaction centers （Fv′/Fm′）, and photochemical quenching coefficient （qp） began to decrease at 14 days after anthesis. However, the maximal efficiency of PS Ⅱ photochemistry （Fv/Fm） decreased slightly until the late period of senescence and the nonphotochemical quenching coefficient （NPQ） increased during flag leaves＇ senescence, As a result, a conflict came into being between absorption and utilization to light energy in flag leaves during senescence, which might accelerate the senescence of flag leaves. Compared with GC8901, the lower plant population of SN1391 during grain filling was helpful to maintain the higher content of photosynthetic pigment, activity of PS II, and Pn in flag leaves during senescence, The delayed decrease in antioxidative enzyme activity and the lower degree of membrane lipid peroxidation in the senescing leaves of SN1391 were beneficial to protect the photosynthetic apparatus, which lead to the prolonged duration of CO2 assimilation. With the increase of N application, the Chl content of SN1391 flag leaves and the efficiency of excitation captured by open PS Ⅱ centers increased. At the same time, the thermal dissipation in SN1391 flag leaves at high N （HN） treatment decreased and Фps Ⅱ improved greatly, which were favorable to the increase of Pn. The SOD, POD, CAT and APX activities in the flag leaves of SN1391 increased markedly at HN tr

关键词： wheat (Triticum aestivum L.) photosynthetic characteristics antioxidative metabolism nitrogen