检索结果-南通市图书馆

兔源肺炎克雷伯氏菌和大肠埃希氏菌的分离鉴定及小鼠感染试验

在线全文

学校读者我要写书评

暂无评论

动物医学进展 2025年第1期46卷 55-61页

作者：张鲁星石晴晴陶梦珂李苗苗赵恒胡功政吴华刘建华河南农业大学动物医学院河南郑州450000

为确定某规模化兔场仔兔呼吸道感染合并腹泻引起死亡的原因,无菌采集病兔气管、肺、肝组织进行病毒和细菌检测。通过细菌分离培养、革兰氏染色、生化鉴定、16S rRNA序列同源性比对分析,确定分离菌株种属。通过药物敏感性试验、耐药基因... 详细信息

为确定某规模化兔场仔兔呼吸道感染合并腹泻引起死亡的原因,无菌采集病兔气管、肺、肝组织进行病毒和细菌检测。通过细菌分离培养、革兰氏染色、生化鉴定、16S rRNA序列同源性比对分析,确定分离菌株种属。通过药物敏感性试验、耐药基因检测及动物回归对分离菌株的耐药性和致病性进行分析。结果显示,病毒检测结果均为阴性;从同一只仔兔的肺脏、气管中分离得到2株肺炎克雷伯氏菌,分别将其命名为KF1、KQ2,从肝脏中分离得到1株大肠埃希氏菌并将其命名为EG3。药敏试验结果显示,菌株KF1、KQ2和EG3均对黏菌素和氨苄青霉素钠耐药,对阿米卡星和氟苯尼考敏感。3株菌均检出耐药基因mcr-1和bla TEM。动物致病性试验显示,KF1组小鼠5 h后死亡50%,24 h全部死亡;混合组小鼠12 h后全部死亡;KQ2和EG3组48 h全部死亡。以上研究表明,大肠埃希氏菌和肺炎克雷伯氏菌的混合感染是引起仔兔死亡的主要原因,3株分离株单独及混合感染均能引起试验小鼠死亡。

关键词：兔肺炎克雷伯氏菌大肠埃希氏菌分离鉴定耐药基因

Brownfield Redevelopment Toward Sustainable Urban Land Use in China

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2007年第2期17卷 127-134页

作者： cao Kang GUAN hua School of Geographic and Oceanographic Sciences Nanjing University Nanjing 210093 China

Brownfield redevelopment is a new urban land use strategy to pursue the ideal of sustainable development. It relieves environmental pressure and resolves the glaring contradiction between urban land idleness and urban sprawl. It addresses issues of urban land use and farmland protection in China. This paper compares brownfield with greenfield, and defines brownfield and its redevelopment. It elaborates general and special government policies for this sustainable land use strategy in the context of China. General policies contain two aspects: clarifying brownfield redevelopment's priority in Chinese urban planning and land use and setting a general quantitative redevelopment target. The extent of the government's special policies, which aim at coordinating three factors in the redevelopment process, namely govern- ments, developers and users, are divided into five areas: statistics and categorization, assessment and remediation, fi- nancial supports and tax incentives, environmental and legal liability, and publicity and guidance. The paper concludes the major functions of different levels of Chinese government in the redevelopment process, i.e. making general strategy, formulating legislation, spectifying regulations and technical standards, estimating and categorizing brownfield sites, drawing up brownfield planning, providing information and financial support, guiding developers, publicizing the strategy to the public, and checking reuse results.

关键词： brownfield redevelopment sustainable development land use

Resistance of grid steel-tube-confined concrete targets against projectile impact: Experimental investigation and analytical engineering model

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2022年第9期18卷 1622-1642页

作者： Dian-yi Song qing-hua Tan Chao-mei Meng Yi-min huang Yang-yueye cao Zhi-gang Jiang Undergraduate School National University of Defense TechnologyChangsha410072PR China College of Aerospace Science and Engineering National University of Defense TechnologyChangsha410073PR China College of Aerospace Engineering Air Force Engineering UniversityXi'an710038PR China

Steel-tube-confined concrete(STCC) targets are provided with excellent anti-penetration performance over semi-infinite concrete(SIC) targets since the steel tube imposes passive restraint on the in-filled concrete during the penetration process. Grid STCC system with square steel tubes is a potential solution to protective structures. In this paper, experiments of 9-cell grid STCC targets penetrated by 12.7 mm Armor Piercing Projectile(APP) were performed. The influence of side length and thickness of steel tube,steel ratio and impact velocity on anti-penetration performance were taken into account. Additionally,single-cell square STCC targets were also designed and tested for comparison with the 9-cell grid STCC targets. Damage modes and parameters of the tested targets were measured and discussed. Moreover,the stiffness of radial confinement of grid STCC targets is achieved according to the elastic solution of infinite cylindrical shell in Winkler medium. Furthermore, the penetration resistance and depth of penetration(DOP) for grid STCC targets are obtained on the basis of the dynamic finite spherical cavityexpansion(FSCE) models including radial confinement effect. It is shown that the 9-cell grid STCC targets with optimal dimension match of thickness and side length of steel tube can reduce the DOP by about17 % and 23 % in comparison with the SIC targets and single-cell square STCC targets, respectively, due to both the confinement of square steel tube to concrete in the impacted cell and the additional confinement of the surrounding cells to the impacted cell;the penetration resistance and DOP of the grid and cellular STCC targets with similar steel ratio is close, and thus the grid STCC targets with simpler manufacturing process and excellent in-plane expandability are preferred in engineering practice;moreover, the predicted results of DOP model based on the FSCE models agree well with the tested results with the maximum disparity less than 12 % and the prop

关键词： Penetration mechanics Grid structural system Steel-tube-confined concrete(STCC)targets Armor piercing projectile(APP) Depth of penetration(DOP) Finite spherical cavity expansion(FSCE)

基于PERK-eIF2α-NF-κB信号通路研究苁蓉散治疗阿尔茨海默病的作用机制

在线全文

学校读者我要写书评

暂无评论

中国药理学通报 2025年第1期41卷 80-87页

作者：王曦龙清华蔡元钦王政喻陈显兵曾楚华湖北民族大学医学部湖北恩施445000 湖北民族大学风湿性疾病发生与干预湖北省重点实验室湖北恩施445000 云南中医药大学基础医学院云南昆明650000

目的基于PERK-eIF2α-NF-κB信号通路研究苁蓉散治疗阿尔茨海默病(Alzheimer’s disease,AD)的作用机制。方法将60只SD大鼠分为正常组,模型组、苁蓉散组(4.62、9.24、18.48 g·kg-1)和安理申组,每组10只。除正常组外其余大鼠组予双侧海... 详细信息

目的基于PERK-eIF2α-NF-κB信号通路研究苁蓉散治疗阿尔茨海默病(Alzheimer’s disease,AD)的作用机制。方法将60只SD大鼠分为正常组,模型组、苁蓉散组(4.62、9.24、18.48 g·kg-1)和安理申组,每组10只。除正常组外其余大鼠组予双侧海马注射Aβ1-42建立AD模型。灌胃结束后进行水迷宫行为学检测学习记忆能力;尼氏染色观察神经元及尼氏小体变化;免疫荧光检测NF-κB核转移情况;透射电镜观察大鼠海马区内质网形态;酶免疫测定Aβ1-42及炎症因子含量;Western blot检测PERK、eIF2α、NF-κB的蛋白表达水平。结果水迷宫结果显示,苁蓉散能提高AD大鼠的逃避潜伏期时间、增加穿越求生平台次数、延长目标象限停留时间(P<0.05或P<0.01);尼氏染色结果显示,苁蓉散各剂量组神经元细胞排列较整齐,胞核存在,尼氏小体较为丰富;免疫荧光表明,苁蓉散可降低AD大鼠脑内NF-κB入核表达(P<0.05或P<0.01);透射电镜结果显示,苁蓉散各剂量组内质网形态整齐、未见明显扩张,结构正常;ELISA结果表明,苁蓉散可降低AD海马中的Aβ1-42,IL-1,TNF-α的含量;Western blot结果显示,苁蓉散各剂量组p-PERK/PERK,p-eIF2α/eIF2α,p-NF-κB p65/NF-κB p65的蛋白比值明显下降(P<0.05或P<0.01)。结论苁蓉散可通过抑制PERK-eIF2α-NF-κB信号通路的活化,缓解神经元细胞ERS状态下免疫炎症反应,以改善AD大鼠的认知功能。

关键词：阿尔兹海默病苁蓉散内质网应激 PERK-eIF2α-NF-κB信号通路炎症 Aβ1-42

Application of multiwalled carbon nanotubes treated by potassium permanganate for determination of trace cadmium prior to flame atomic absorption spectrometry

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2007年第10期19卷 1266-1271页

作者： XIAO Jun-ping ZHOU qing-xiang BAI hua-hua Department of Chemistry University of Science and Technology Beijing Beijing 100083 China Henan Key Laboratory for Environmental Pollution Control School of Chemistry and Environmental Sciences Henan Normal University Xinxiang 453007 China

In this study we investigated the enrichment ability of oxidized multiwalled carbon nanotubes （MWCNTs） and established a new method for the determination of trace cadmium in environment with flame atomic absorption spectrometry. The MWCNTs were oxidized by potassium permanganate under appropriate conditions before use as preconcentration packing. Parameters influencing the recoveries of target analytes were optimized. Under optimal conditions, the target analyte exhibited a good linearity （R^2=0.9992） over the concentration range 0.5-50 ng/ml. The detection limit and precision of the proposed method were 0.15 ng/ml and 2.06%, respectively. The proposed method was applied to the determination of cadmium in real-world environmental samples and the recoveries were in the range of 91.3%-108.0%. All these experimental results indicated that this new procedure could be applied to the determination of trace cadmium in environmental waters.

关键词： multiwalled carbon nanombes (MWCNTs) solid-phase extraction flame atomic absorption spectrometry

Experimental and computational investigation of novel vertical tail buffet suppression method for high sweep delta wing

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2015年第1期58卷 147-157页

作者： ZHANG qing hua RuHao YE ZhengYin School of Aeronautics Northwestern Polytechnical University

Our research aim is to investigate the buffet alleviation effect of static or vibrating bulges attached on the forebody surface of the *** and numerical simulations on a model consisting of a sharp-edged,70°-leading edge sweep delta wing and twin swept back vertical tails were *** with different bulges were tested and computed at 10 and 20 m/s of free stream velocity at angles of attack ranging from 20°–50°.Dynamic strain gauge and multichannel data acquisition and analysis system were employed for the measurement of unsteady root strain on the vertical *** and computational results show that both static and vibrating bulges behave effectively as a novel tool to alleviate tail buffet,and the alleviation effect depends largely on the vibrating ***,one-sided bulge can only alleviate the buffeting response for the tail of the same side,and it has no obvious alleviation effect for the opposite *** of the spectral analysis reveal that there are generally three peaks of spectral density for aircrafts of this configuration,and bulges used in this paper could alleviate tail buffeting,but the total lift and drag of the whole model show no obvious deviation compared to the base model and the dominant frequency of the vibration of the tails has not shifted.

关键词： forebody bulge delta wing/twin tail configuration vortex breakdown self-induction theory buffet suppression

An energy sum constraint of event mixing for Bose-Einstein correlations in reactions with ππX final states around 1 GeV

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2018年第7期42卷 47-52页

作者： qing-hua He Department of Nuclear Science and Engineering Nanjing University of Aeronautics and Astronautics （NUAA） Nanjing 210016 China

We present a new event mixing technique for measuring two-pion Bose-Einstein correlations （BEC） in reactions with only two identical bosons among three final state particles. This new mixing method contains a missing mass consistency （MMC） cut and an energy sum order （ESO） cut. Unlike the previous proposed pion energy cut, which abandons nearly half the original events, the ESO cut does not eliminate any original events and hence improves the statistics of both original events and mixed events. Numerical tests using the γp→π0π0p events around 1 GeV are carried out to verify the validity of the ESO cut. This cut is able to reproduce the relative momentum distribution of the original events in the absence of BEC effects. In addition, its ability to observe BEC effects is tested by an event sample in the presence of BEC effects. Simulation results show the BEC effects can be observed clearly as an enhancement in the correlation function, and the BEC parameters extracted by this event mixing cut are consistent with the input BEC parameters.

关键词： Bose-Einstein correlations photoproduction event mixing

S空位及非金属掺杂单层Bi_(2)S_(2)Se的第一性原理研究

在线全文

学校读者我要写书评

暂无评论

原子与分子物理学报 2025年第1期42卷 127-134页

作者：张建华王敏陈畅曹倩徐银湖北大学资源环境学院武汉430062

Bi_(2)S_(2)Se是一种新兴的具有优异光电性能的材料,因此受到了广泛的关注.本研究采用第一性原理方法和开源程序,研究了本征单层Bi_(2)S_(2)Se以及掺杂非金属元素X(X=P,Cl,Br和I)和S空位的体系的电子结构和光学特性.计算结果表明,改性... 详细信息

Bi_(2)S_(2)Se是一种新兴的具有优异光电性能的材料,因此受到了广泛的关注.本研究采用第一性原理方法和开源程序,研究了本征单层Bi_(2)S_(2)Se以及掺杂非金属元素X(X=P,Cl,Br和I)和S空位的体系的电子结构和光学特性.计算结果表明,改性后出现了晶格缺陷.含S空位和P、Cl、Br掺杂体系的带隙减少,而I掺杂体系的带隙增加.同时,含S空位和Cl、Br、I掺杂体系的费米能级穿过导带底,而P掺杂体系的费米能级穿过价带顶.所有改性体系在费米能级附近都出现了缺陷能级或杂质能级,表现出较高的可见光吸收能力和散射能力,改性体系的对可见光的吸收能力和散射能力有所增加.

关键词： Bi_(2)S_(2)Se 掺杂电子结构光学性质第一性原理

A mathematical model of cortical bone remodeling at cellular level under mechanical stimulus

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2012年第6期28卷 1678-1692页

作者： qing-hua Qin Ya-Nan Wang Research School of Engineering The Australian National University

A bone cell population dynamics model for cor- tical bone remodeling under mechanical stimulus is devel- oped in this paper. The external experiments extracted from the literature which have not been used in the creation of the model are used to test the validity of the model. Not only can the model compare reasonably well with these ex- perimental results such as the increase percentage of final values of bone mineral content （BMC） and bone fracture en- ergy （BFE） among different loading schemes （which proves the validity of the model）, but also predict the realtime devel- opment pattern of BMC and BFE, as well as the dynamics of osteoblasts （OBA）, osteoclasts （OCA）, nitric oxide （NO） and prostaglandin E2 （PGE2） for each loading scheme, which can hardly be monitored through experiment. In conclusion, the model is the first of its kind that is able to provide an in- sight into the quantitative mechanism of bone remodeling at cellular level by which bone cells are activated by mechan- ical stimulus in order to start resorption/formation of bone mass. More importantly, this model has laid a solid foun- dation based on which future work such as systemic control theory analysis of bone remodeling under mechanical stimu- lus can be investigated. The to-be identified control mecha- nism will help to develop effective drugs and combined non- pharmacological therapies to combat bone loss pathologies. Also this deeper understanding of how mechanical forces quantitatively interact with skeletal tissue is essential for the generation of bone tissue for tissue replacement purposes in tissue engineering.

关键词： Cortical bone remodeling Cell population dy-namics Mechanotransduction Mechanosensitivity Bonefracture energy - Bone mineral content