检索结果-南通市图书馆

SCALE EFFECT OF I MPINGING PRESSURE CAUSED BY SUBMERGED JET

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2005年第4期17卷 478-482页

作者： tian zhong xu wei-lin wang wei liu shan-jun DONG Jian-wei State Key Hydraulics Laboratory of High Speed Flows Sichuan University Chengdu 610065 China Military Oil Supply Engineering Department Logistical Engineering University Chongqing 400016China

The characteristics of the impinging pressure at the jet equipment where the maximum jet velocity can reach 50m/s were studied. By comparing the impinging pressure with the one measured at the low velocity conditions, two conclusions of the scale effect are drawn： firstly, the velocity attenuation degree is smaller than that of low velocity jet, and secondly, the relative impinging width is narrower than that of low-velocity jet. The reasons of the scale effect of the impinging pressure were elucidated through numerical simulation.

关键词： scale effect impinging pressure high-velocity jet numerical simulation

在线全文

学校读者我要写书评

暂无评论

Bone Research 2024年第1期12卷 122-136页

作者： Nan-Yu Zou Ran liu Mei Huang Yu-Rui Jiao Jie wei Yangzi Jiang Wen-Zhen He Min Huang Yi-Li xu ling liu Yu-Chen Sun Mi Yang Qi Guo Yan Huang tian Su Ye Xiao wei-shan wang Chao Zeng Guang-Hua Lei Xiang-Hang Luo Chang-jun Li Department of Endocrinology Endocrinology Research CenterXiangya Hospital of Central South UniversityChangshaHunan 410008China Department of Orthopaedics Xiangya Hospital of Central South UniversityChangshaHunan 410008China Department of Epidemiology and Health Statistics Xiangya School of Public HealthCentral South UniversityChangshaChina Hunan Key Laboratory of Joint Degeneration and Injury ChangshaHunan 410008China Key Laboratory of Aging-related Bone and Joint Diseases Prevention and Treatment Ministry of EducationXiangya HospitalCentral South UniversityChangshaChina School of Biomedical Sciences Institute for Tissue Engineering and Regenerative MedicineFaculty of MedicineThe Chinese University of Hong KongHong Kong SARChina Department of Orthopaedics The First Affiliated Hospital of Shihezi UniversityShiheziXinjiangChina National Clinical Research Center for Geriatric Disorders Xiangya HospitalCentral South UniversityChangshaHunan 410008China

Skeletal stem/progenitor cell(SSPC)senescence is a major cause of decreased bone regenerative potential with aging,but the causes of SSPC senescence remain *** this study,we revealed that macrophages in calluses secrete prosenescent factors,including grancalcin(GCA),during aging,which triggers SSPC senescence and impairs fracture *** injection of human rGCA in young mice induced SSPC senescence and delayed fracture *** deletion of Gca in monocytes/macrophages was sufficient to rejuvenate fracture repair in aged mice and alleviate SSPC ***,GCA binds to the plexin-B2 receptor and activates Arg2-mediated mitochondrial dysfunction,resulting in cellular *** of Plxnb2 in SSPCs impaired fracture *** of GCA-neutralizing antibody enhanced fracture healing in aged ***,our study revealed that senescent macrophages within calluses secrete GCA to trigger SSPC secondary senescence,and GCA neutralization represents a promising therapy for nonunion or delayed union in elderly individuals.

关键词： healing union senescence

盐碱胁迫对‘冬红’花楸生长、生理及光合特性的影响

在线全文

学校读者我要写书评

暂无评论

草地学报 2024年第2期32卷 480-488页

作者：黄荣雁路程伟许嵘孙正轩房莉陈钦华马天意刘殿辉孟维珊王一顺饶欢刘俊辰齐齐哈尔大学生命科学与农林学院黑龙江齐齐哈尔161006 东北林业大学林学院黑龙江哈尔滨150040 黑龙江省农业科学院畜牧兽医分院黑龙江齐齐哈尔161006

为探究‘冬红’花楸(Sorbus sibirica‘DongHong’)的耐盐特性,本试验以‘冬红’花楸幼苗为材料,采用中性盐NaCl、碱性盐NaHCO_(3)、混合盐对‘冬红’花楸幼苗胁迫处理,分析不同浓度盐碱胁迫对‘冬红’花楸生长、生理及光合指标的影响... 详细信息

为探究‘冬红’花楸(Sorbus sibirica‘DongHong’)的耐盐特性,本试验以‘冬红’花楸幼苗为材料,采用中性盐NaCl、碱性盐NaHCO_(3)、混合盐对‘冬红’花楸幼苗胁迫处理,分析不同浓度盐碱胁迫对‘冬红’花楸生长、生理及光合指标的影响。结果表明:随着盐浓度的增加,冬红花楸根总长度、根表面积、根体积、根平均直径、根尖数等指标均受到不同程度的抑制,中性盐抑制程度最轻,碱性盐在浓度为200 mmol·L^(-1)时抑制达到最大,出现表皮脱落、碱蚀等现象;根冠比及根生物量呈降低趋势,中性盐降低幅度较小;丙二醛含量和脯氨酸含量呈上升趋势,超氧化物氢化酶和过氧化物酶呈先上升后下降趋势;胞间CO_(2)浓度呈现上升趋势,净光合速率、气孔导度及蒸腾速率均呈下降趋势。利用主成分分析筛选出生物量、总根长、根表面积、根体积、根尖数、净光合速率、蒸腾速率、气孔导度可作为‘冬红’花楸耐盐性评价的参考指标。

关键词： ‘冬红’花楸盐碱胁迫生长特性生理特性光合特性

Laboratory model study of the effect of aeration on axial velocity attenuation of turbulent jet flows in plunge pool

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

Journal of Hydrodynamics 2015年第6期27卷 913-918页

作者：邓军张法星田忠许唯临刘斌卫望汝 State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University

In the laboratory model experiment, the velocities of the jet flow along the axis are measured, using the CQY-Z8a velocity-meter. The velocity attenuations of the jet flow along the axis under different conditions are studied. The effects of the aeration concentration, the initial jet velocity at the entry and the thickness of the jet flow on the velocity attenuation of the jet flow are analyzed. It is seen that the velocity attenuation of the jet flow along the axis sees a regular variation. It is demonstrated by the test results that under the experimental conditions, the velocity along the axis decreases linearly. The higher the air concentration is, the faster the velocity will be decayed. The absolute value of the slope K increases with the rise of the air concentration. The relationship can be defined as K = AC~ ＋ Kb. The coefficient A is 0.03 under the experimental conditions. With the low air concentration of the jet flow, the thinner the jet flow is, the faster the velocity will be decayed. With the increase of the air concentra- tion, the influence of the thickness of the jet flow on the velocity attenuation is reduced. When the air concentration is increased to a certain value, the thickness of the jet flow may not have any influence on the velocity attenuation. The initial jet velocity itself at the entry has no influence on the variation of the velocity attenuation as the curves of the velocity attenuation at different velocities at the entry are practically parallel, even coinciding one with another. Therefore, improving the air concentration of the jet flow and disper- sing the jet flow in the plunge pool could reduce the influence of the jet flow on the scour.

关键词： jet flow air concentration velocity

在线全文

学校读者我要写书评

暂无评论

高速淹没冲击射流的压强特性

水利学报 2005年第4期36卷 401-404页

作者：田忠许唯临王韦刘善均四川大学高速水力学国家重点实验室四川成都610065

在试验室中研究了高速淹没射流对挡板的冲击压强特性。射流出流速度为10 36m s～53 86m s、厚度为3cm。测得最大时均冲击压强沿射流流程的变化规律以及挡板上的时均冲击压强的分布特性及扩散宽度。试验结果表明:在高流速范围内,挡板上... 详细信息

在试验室中研究了高速淹没射流对挡板的冲击压强特性。射流出流速度为10 36m s～53 86m s、厚度为3cm。测得最大时均冲击压强沿射流流程的变化规律以及挡板上的时均冲击压强的分布特性及扩散宽度。试验结果表明:在高流速范围内,挡板上的最大时均无量纲冲击压强与无量纲射流流程的平方根之间存在良好的直线关系。当射流流程大于80倍出流厚度时,淹没射流产生的冲击压强可以忽略。挡板上的时均压强分布存在较好的自模性,近似符合高斯分布。最后给出了挡板冲击区宽度的定量描述。

关键词：高速射流冲击压强淹没射流实验研究

Hemodynamic changes of fractional flow reserve after double kissing crush and provisional stenting technique for true bifurcation lesions

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2012年第15期125卷 2658-2662页

作者： YE Fei CHEN Shao-liang ZHANG jun-jie ZHU zhong-sheng KAN Jing tian Nai-liang lin Song liu Zhi-zhong YOU wei xu Hai-mei xu Jing Department of Cardiology Nanjing First Hospital of NanjingMedical University Nanjing Jiangsu 210006 China

Background Fractional flow reserve （FFR）-guided percutaneous coronary intervention （PCI） is associated with fewer unfavorable events. However, the hemodynamic change in FFR after different stenting approaches for bifurcation lesions is still not fully studied. The aim of this study was to analyze the hemodynamic changes in FFR after double kissing （DK） crush and provisional side branch （SB） stenting （PS） for true coronary bifurcation lesions. Methods Seventy-five patients with true bifurcated lesions were randomly divided into DK （n=38） and PS （n=37） groups. Additional SB stenting in the PS group was required if there was any pinched SB ostium 〉70% stenosis, or ≥ type B dissection, or TIMI flow 〈grade 3. FFR at hyperemia in the main vessel （MV） and SB was measured prior- and post-stenting, and at 8 months follow-up. Results Baseline clinical, angiographic and lesion characteristics were matched well between the two groups, with the exception of the final kissing balloon inflation （FKBI, 100.0% in the DK vs. 83.8% in the PS group, P 〈0.001）. Baseline FFR was comparable between the DK and the PS groups, however, the acute gain and late loss of SB FFR at 8-month follow-up in the DK group were 0.18±0.15 and -0.06±0.11, compared to 0.12±0.18 （P=0.044） and -0.002±0.07 （P=-0.037） in the PS group, respectively. MV FFR post-stenting 〉0.94 was seen in about 40% of patients. There was no significant difference in the clinical events at 1-year follow-up between the two groups. Conclusions DK crush was associated with improved acute gain and late loss of SB FFR. The lower rate of FFR 〉0.94 after stenting underscored the further improvement of stentinq quality.

关键词： double kissing crush bifurcation, provisional fractional flow reserve

Dihydroartemisinin inhibits plasmid transfer in drug-resistant Escherichia coli via limiting energy supply

在线全文

学校读者我要写书评

暂无评论

动物学研究(英文) 2023年第5期44卷 894-904页

作者： xue-Yang wang Huang-wei Song tian Yi Ying-Bo Shen Chong-shan Dai Cheng-Tao Sun De-jun liu Jian-zhong Shen Cong-Ming Wu Yang wang National Key Laboratory of Veterinary Public Health Security College of Veterinary MedicineChina Agricultural UniversityBeijing 100193China Guangdong Laboratory for lingnan Modern Agriculture GuangzhouGuangdong 510642China

Conjugative transfer of antibiotic resistance genes(ARGs)by plasmids is an important route for ARG *** increasing number of antibiotic and nonantibiotic compounds have been reported to aid the spread of ARGs,highlighting potential challenges for controlling this type of horizontal *** of conjugation inhibitors that block or delay the transfer of ARG-bearing plasmids is a promising strategy to control the propagation of antibiotic *** such inhibitors are rare,they typically exhibit relatively high toxicity and low efficacy in vivo and their mechanisms of action are inadequately ***,we studied the effects of dihydroartemisinin(DHA),an artemisinin derivative used to treat malaria,on *** inhibited the conjugation of the IncI2 and IncX4 plasmids carrying the mobile colistin resistance gene(mcr-1)by more than 160-fold in vitro in Escherichia coli,and more than two-fold(IncI2 plasmid)in vivo in a mouse *** also suppressed the transfer of the IncX3 plasmid carrying the carbapenem resistance gene bla_(NDM-5)by more than twofold in *** of intracellular adenosine triphosphate(ATP)and proton motive force(PMF),in combination with transcriptomic and metabolomic analyses,revealed that DHA impaired the function of the electron transport chain(ETC)by inhibiting the tricarboxylic acid(TCA)cycle pathway,thereby disrupting PMF and limiting the availability of intracellular ATP for plasmid conjugative ***,expression levels of genes related to conjugation and pilus generation were significantly down-regulated during DHA exposure,indicating that the transfer apparatus for conjugation may be *** findings provide new insights into the control of antibiotic resistance and the potential use of DHA.

关键词： Dihydroartemisinin Plasmid mcr-1 bla_(NDM-5) Conjugation inhibitors TCA cycle

Subclinical hypothyroidism is associated with lipid-rich plaques in patients with coronary artery disease as assessed by optical coherence tomography

在线全文

学校读者我要写书评

暂无评论

Journal of Geriatric Cardiology 2018年第8期15卷 534-539页

作者： Xiao-Qing CAI Feng tian tian-Wen HAN Dong-Kai shan Yang liu wei-jun YIN Jing Jing Qiang xu Yun-Dai CHEN Department of Cardiology Chinese PLA General Hospital Beijing China Department of Cardiology Chinese PLA Lanzhou General Hospital Lanzhou China Department of Cardiology Chinese PLA 305 Hospital Beijing China School of Medicine Nankai University Tianjin China

Background Subclinical hypothyroidism （SCH） has recently been acknowledged as an unconventional risk factor for coronary artery disease （CAD） and characterized by poor prognosis, which may be due to atherosclerotic plaque characteristics. We conducted this study to observe coronary plaque characteristics in coronary artery disease patients with concomitant SCH. Methods Patients with coronary artery disease were enrolled in the study and divided into an SCH group （patients, n = 26; plaques, n = 35） and a non-SCH group （patients, n = 52; plaques, n = 66）. They were divided 1：2 according to propensity-matched analysis including age, diabetes mellitus, gender, CAD severity and culprit vessel. Optical coherence tomography （OCT） imaging was performed on all patients, and images were analyzed by two inde- pendent investigators. Lipid-rich plaques （LRP）, the precursor of vulnerable plaques, were defined as having more than one quadrant occu- pied with lipid pool. Maximum lipid arcs were simultaneously recorded. Fibrotic plaques and calcific plaques were also identified. The pres- ence of coronary dissection, plaque erosion, thrombus, macrophage, calcific nodule, thin-cap fibroatheroma and micro channel were all noted. Results The ratio of LRP in SCH group was significantly higher than that in non-SCH group （54% vs. 30.3%, P = 0.037）. That was the case as well for the maximum lipid arcs value （181.5°± 61.6° vs. 142.1° 4± 35.9°, p = 0.046）. While thin-cap fibroatheroma （TCFA） was detected, no difference was identified between the two groups in either TCFA ratio （20% vs. 16.7%, P = 0.579） or fibrous cap thickness （57.5 4± 14.0 vs. 63.5 4±10.7 gin, P = 0.319）. Other OCT characteristics such as dissection, plaque erosion, thrombus, macrophage shadow and calcific nodule were also similar. ConcLusion Higher ratio of LRP with greater lipid arc in SCH patients may be related to the plaque instability and poor prognosis in CAD patients with SCH.

关键词： Coronary artery disease Optical coherence tomography Plaque characteristics Subclinical hypothyroidism

Deep carbon cycles constrained by a large-scale mantle Mg isotope anomaly in eastern China

在线全文

学校读者我要写书评

暂无评论

National Science Review 2017年第1期4卷 111-120页

作者： Shu-Guang Li wei Yang shan Ke xunan Meng Hengci tian Lijuan xu Yongsheng He Jian Huang xuan-Ce wang Qunke Xia weidong Sun Xiaoyong Yang zhong-Yuan Ren Haiquan wei Yongsheng liu Fancong Meng jun Yan State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences CAS Key Laboratory of Crust-Mantle Materials and Environments School of Earth and Space SciencesUniversity of Science and Technology of China Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of Sciences The Institute for Geoscience Research Department of Applied GeologyCurtin University School of Earth Sciences Zhejiang University Key Laboratory of Mineralogy and Metallogeny Guangzhou Institute of GeochemistryChinese Academy of Sciences Institute of Geology China Earthquake Administration State Key Laboratory of Geological Processes and Mineral Resources Faculty of Earth SciencesChina University of Geosciences Institute of Geology Chinese Academy of Geological Sciences School of Resources and Environmental Engineering Hefei University of Technology

Although deep carbon recycling plays an important role in the atmospheric CO2budget and climate changes through geological time,the precise mechanisms remain poorly *** recycled sedimentary carbonate through plate subduction is the main light-δ26Mg reservoir within deep-Earth,Mg isotope variation in mantle-derived melts provides a novel perspective when investigating deep carbon ***,we show that the Late Cretaceous and Cenozoic continental basalts from 13 regions covering the whole of eastern China have low δ26Mg isotopic compositions,while the Early Cretaceous basalts from the same area and the island arc basalts from circum-Paciic subduction zones have mantle-like or heavy Mg isotopic ***,a large-scale mantle low δ26Mg anomaly in eastern China has been delineated,suggesting the contribution of sedimentary carbonates recycled into the upper mantle,but limited into the lower *** large-scale spatial and temporal variation of Mg isotopes in the mantle places severe constraints on deep carbon recycling via oceanic subduction.

关键词： Mg isotopes deep carbon cycling continental basalts eastern China circum-Paciic subduction zones mantle geochemistry