检索结果-南通市图书馆

机械与电子 2001年第6期19卷 43-44页

作者：曲军 albert j.shih 北卡罗来纳州立大学机械与航空系美国北卡罗来纳罗利27695

论述了回转体电火花线切割的原理及应用 ,实验并分析了电火花脉冲宽度、线电极进给速度和工件旋转速度等加工参数对加工表面特性的影响 ,借助于扫描电子显微镜识别和量化了加工表面的重凝固层和热影响层 .

关键词：电火花线切割回转体表面粗糙度重凝固层热影响层扫描电子显微镜

在线全文

学校读者我要写书评

暂无评论

超声振动辅助活检穿刺对取样性能影响的研究

电加工与模具 2018年第3期 50-53页

作者：蔡晨需魏鹏鹏谭磊张洪才张勤河 albert j.shih 山东大学机械工程学院高效洁净机械制造教育部重点试验室机械工程国家级实验教学示范中心山东济南250061 Department of Mechanical Engineering and Department of Biomedical EngineeringUniversity of MichiganAnn ArborMI 48109

通过比较不同振动频率下的穿刺孔形态和大小,探究了超声振动辅助活检穿刺对取样孔面积、周长(即裂纹长度)、区域圆度等取样性能的影响。将新鲜猪肝组织放在活检穿刺实验台上,分别在相同电压、不同振动频率(20、30、50、60、70 k Hz)和... 详细信息

通过比较不同振动频率下的穿刺孔形态和大小,探究了超声振动辅助活检穿刺对取样孔面积、周长(即裂纹长度)、区域圆度等取样性能的影响。将新鲜猪肝组织放在活检穿刺实验台上,分别在相同电压、不同振动频率(20、30、50、60、70 k Hz)和相同频率、不同激励电压(0、20、40、60、80 V)的条件下进行活检穿刺实验。结果表明:随着振动频率的增加,取样孔面积和周长均减小;随着振动幅度的增加,取样孔面积和周长先减小、后增大,区域圆度都趋于增大。

关键词：活检穿刺超声振动振动频率振动幅度取样性能

超声振动辅助活检穿刺对取样性能影响的实验研究

在线全文

学校读者我要写书评

暂无评论

超声振动辅助活检穿刺对取样性能影响的实验研究

Hepatic inflammation and progressive liver fibrosis in chronic liver disease

特种加工技术智能化与精密化——第17届全国特种加工学术会议

作者：蔡晨需魏鹏鹏谭磊张洪才张勤河 albert j.shih 山东大学机械工程学院高效洁净机械制造教育部重点试验室 Department of Mechanical Engineering and Department of Biomedical Engineering University of Michigan

在临床医学中,穿刺活检是实现微创介入检查的重要手段,具有创伤小、恢复快、费用低等优点,应用十分普遍。超声振动辅助活检穿刺是目前很重要的研究方向,在活检针上附加一定频率的超声振动可以减小穿刺力,进而增加穿刺精度,减小病人疼痛... 详细信息

在临床医学中,穿刺活检是实现微创介入检查的重要手段,具有创伤小、恢复快、费用低等优点,应用十分普遍。超声振动辅助活检穿刺是目前很重要的研究方向,在活检针上附加一定频率的超声振动可以减小穿刺力,进而增加穿刺精度,减小病人疼痛。本文通过比较不同振动频率下穿刺孔的形态和大小来探究超声振动对活检穿刺取样性能的影响,取样性能包括取样孔的面积、周长(裂纹长度)以及区域圆度。区域圆度是一个物体接近最平滑的形状(圆)的定量描述,区域圆度越小,物体形状接近圆的程度越高。在现代医学研究中,取出的样本越饱满越接近圆柱形,后续的病理切片越能提供更详细的细胞组织信息,可以提供更多的从病变细胞到正常细胞变化过程的信息。本实验中由于空心针内取下组织较小,后续处理及做成生物切片难度较大,因此用研究空心针穿刺猪肝组织后留下的穿刺孔的形貌特征替代直接研究针取下的软组织。在实验中将新鲜猪肝组织放在活检穿刺实验台上,分别在相同电压,改变振动频率为20、30、50、60、70kHz和相同频率,改变激励电压为0、20、40、60、80V的条件下进行活检穿刺,穿刺完成后将组织从工作台取下进行染色包埋切片,并在显微演示装置下观察照相。通过计算照片中像素点个数计算出穿刺孔面积,测量边线长度得到裂纹长度,再利用测得的穿刺孔裂纹长度和面积,根据公式计算得到各穿刺孔对应的区域圆度。实验结果表明,穿刺孔的面积随频率的增加有减小的趋势,表明取下组织的截面积随振动频率增加而降低。裂纹长度即穿刺孔的周长随频率的增加有减小的趋势,这是由于随着振动频率增加,超声振动系统功率降低,在以相同穿刺速度进给时,接触的时间相同,超声振动系统通过活检针传递到组织的能量相差很大,根据断裂力学理论,裂纹处传递能量越多,产生的裂纹长度越长。而随着激励电压即振动幅度的增加,穿刺孔面积和裂纹长度均呈现先下降后增加的趋势。随着振动频率和激励电压的增加区域圆度均变大,说明穿刺孔接近圆的程度随频率和激励电压增加而降低,即取样的组织与圆接近的程度随频率增加而降低。

关键词：活检穿刺超声振动振动频率振动幅度取样性能

来源： cnki会议 cnki会议评论

在线全文

学校读者我要写书评

暂无评论

World journal of Gastroenterology 2014年第10期20卷 2515-2532页

作者： albert j Czaja Division of Gastroenterology and Hepatology Mayo Clinic College of Medicine Rochester MN 55905 United States

Chronic liver inflammation drives hepatic fibrosis,and current immunosuppressive,anti-inflammatory,and anti-viral therapies can weaken this *** fibrosis is reversed,stabilized,or prevented in 57%-79%of patients by conventional treatment regimens,mainly by their anti-inflammatory ***,however,are commonly incomplete and inconsistently *** fibrotic mechanisms associated with liver inflammation have been clarified,and anti-fibrotic agents promise to improve outcomes as adjunctive *** C virus and immune-mediated responses can activate hepatic stellate cells by increasing oxidative stress within *** can be synthesized by activated hepatic stellate cells and promote the production of reactive oxygen ***-oxidants(Nacetylcysteine,S-adenosyl-L-methionine,and vitamin E)and angiotensin inhibitors(losartin)have had antifibrotic actions in preliminary human studies,and they may emerge as supplemental ***-fibrotic agents presage a new era of supplemental treatment for chronic liver disease.

关键词： Inflammation Fibrosis Cirrhosis Treatment Anti-oxidants Angiotensin receptors Investigational drugs

Examining pathogenic concepts of autoimmune hepatitis for cues to future investigations and interventions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World journal of Gastroenterology 2019年第45期25卷 6579-6606页

作者： albert j Czaja Division of Gastroenterology and Hepatology Mayo Clinic College of Medicine and Science

BACKGROUND Multiple pathogenic mechanisms have been implicated in autoimmune hepatitis,but they have not fully explained susceptibility,triggering events,and maintenance or escalation of the ***,they have not identified a critical defect that can be *** goals of this review are to examine the diverse pathogenic mechanisms that have been considered in autoimmune hepatitis,indicate investigational opportunities to validate their contribution,and suggest interventions that might evolve to modify their *** abstracts were identified in PubMed by multiple search *** length articles were selected for review,and secondary and tertiary bibliographies were *** and epigenetic factors can affect susceptibility by influencing the expression of immune regulatory *** dysfunction,possibly related to deficient production of programmed cell death protein-1,can allow autoreactive T cells to escape deletion,and alterations in the intestinal microbiome may help overcome immune tolerance and affect gender *** factors may trigger the disease or induce epigenetic changes in gene *** mimicry,epitope spread,bystander activation,neo-antigen production,lymphocytic polyspecificity,and disturbances in immune inhibitory mechanisms may maintain or escalate the *** that modify epigenetic effects on gene expression,alter intestinal dysbiosis,eliminate deleterious environmental factors,and target critical pathogenic mechanisms are therapeutic possibilities that might reduce risk,individualize management,and improve *** conclusion,diverse pathogenic mechanisms have been implicated in autoimmune hepatitis,and they may identify a critical factor or sequence that can be validated and used to direct future management and preventive strategies.

关键词： Autoimmune hepatitis Pathogenesis Epigenetics Molecular mimicry Epitope spread Intestinal microbiome

Incorporating mucosal-associated invariant T cells into the pathogenesis of chronic liver disease

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World journal of Gastroenterology 2021年第25期27卷 3705-3733页

作者： albert j Czaja Department of Medicine Mayo Clinic College of Medicine and ScienceRochesterMN 55905United States

Mucosal-associated invariant T(MAIT)cells have been described in liver and nonliver diseases,and they have been ascribed antimicrobial,immune regulatory,protective,and pathogenic *** goals of this review are to describe their biological properties,indicate their involvement in chronic liver disease,and encourage investigations that clarify their actions and therapeutic *** abstracts were identified in PubMed by multiple search terms,and bibliographies were *** cells are activated by restricted non-peptides of limited diversity and by multiple inflammatory *** pro-inflammatory,anti-inflammatory,and immune regulatory cytokines are released;infected cells are eliminated;and memory cells *** MAIT cells are hyper-activated,immune exhausted,dysfunctional,and depleted in chronic liver *** phenotype lacks disease-specificity,and it does not predict the biological *** cells have presumed protective actions in chronic viral hepatitis,alcoholic hepatitis,non-alcoholic fatty liver disease,primary sclerosing cholangitis,and decompensated *** have pathogenic and pro-fibrotic actions in autoimmune hepatitis and mixed actions in primary biliary *** factors in the hepatic microenvironment(cytokines,bile acids,gut-derived bacterial antigens,and metabolic by-products)may modulate their response in individual *** manipulations of function are warranted to establish an association with disease severity and *** conclusion,MAIT cells constitute a disease-nonspecific,immune response to chronic liver inflammation and *** pathological role has been deduced from their deficiencies during active liver disease,and future investigations must clarify this role,link it to outcome,and explore therapeutic interventions.

关键词： Innate-like lymphocytes Antimicrobial Immune regulatory Pathogenic Mucosal-associated invariant T cell

Factoring the intestinal microbiome into the pathogenesis of autoimmune hepatitis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World journal of Gastroenterology 2016年第42期22卷 9257-9278页

作者： albert j Czaja Division of Gastroenterology and Hepatology Mayo Clinic College of Medicine

The intestinal microbiome is a reservoir of microbial antigens and activated immune cells. The aims of this review were to describe the role of the intestinal microbiome in generating innate and adaptive immune responses, indicate how these responses contribute to the development of systemic immune-mediated diseases, and encourage investigations that improve the understanding and management of autoimmune hepatitis. Alterations in the composition of the intestinal microflora(dysbiosis) can disrupt intestinal and systemic immune tolerances for commensal bacteria. Toll-like receptors within the intestine can recognize microbe-associated molecular patterns and shape subsets of T helper lymphocytes that may cross-react with host antigens(molecular mimicry). Activated gutderived lymphocytes can migrate to lymph nodes, and gut-derived microbial antigens can translocate to extra-intestinal sites. Inflammasomes can form within hepatocytes and hepatic stellate cells, and they can drive the pro-inflammatory, immune-mediated, and fibrotic responses. Diet, designer probiotics, vitamin supplements, re-colonization methods, antibiotics, drugs that decrease intestinal permeability, and molecular interventions that block signaling pathways may emerge as adjunctive regimens that complement conventional immunosuppressive management. In conclusion, investigations of the intestinal microbiome are warranted in autoimmune hepatitis and promise to clarify pathogenic mechanisms and suggest alternative management strategies.

关键词： Intestinal microbiome Inflammasomes Autoimmune hepatitis Dysbiosis Toll-like receptors

Recent Trends in Satellite-Derived Chlorophyll and Aerosol Optical Depth Together with Simulated Dimethylsulfide in the Eastern China Marginal Seas

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 Ocean University of China 2022年第2期21卷 486-498页

作者： QU Bo GABRIC albert j. School of Science Nantong UniversityNantong 266000China School of Environment and Science Griffith UniversityBrisbaneQLDAustralia

The biogenic compound dimethylsulfide(DMS)produced by a range of marine biota is the major natural source of re-duced sulfur to the atmosphere and plays a major role in the formation and evolution of aerosols,potentially affecting *** spatio-temporal distribution of satellite-derived chlorophyll_a(CHL)and aerosol optical depth(AOD)for the recent years(2011-2019)in the Eastern China Marginal Seas(ECMS)(25°-40°N,120°-130°E)are *** seasonal CHL peaks occurred during late April and the CHL distribution displays a clear zonal *** CHL was also observed along the northern and western coastlines during summer and winter *** analysis shows that mean CHL decreases by about 10%over the 9-year study period,while AOD was higher in south and lower in north during summertime.A genetic algorithm technique is used to calibrate the key model parameters and simulations are carried out for 2015,a year when field data was *** simulation results show that DMS seawater concentration ranges from 1.56 to 5.88 nmol L^(−1) with a mean value of 2.76 nmol L^(−1).DMS sea-air flux ranges from 2.66 to 5.00mmol m^(−2) d^(−1) with mean of 3.80mmol m^(−2) d^(−1).Positive correlations of about 0.5 between CHL and AOD were found in the study region,with higher correlations along the coasts of jiangsu and Zhejiang *** elevated CHL concentration along the west coast is correlated with increased sea-water concentrations of DMS in the *** results suggest a possible influ-ence of DMS-derived aerosol in the local ECMS atmosphere,especially along the western coastline of ECMS.

关键词： dimethylsulfide sea-to-air flux chlorophyll-a aerosol optical depth biogeochemical model Eastern China Marginal Seas

Using genetic algorithms to calibrate a dimethylsulfide production model in the Arctic Ocean

在线全文

学校读者我要写书评

暂无评论

Chinese journal of Oceanology and Limnology 2010年第3期28卷 573-582页

作者：瞿波 GABRIC j.albert Nantong University Griffith University

The global climate is intimately connected to changes in the polar oceans. The variability of sea ice coverage affects deep-water formations and large-scale thermohaline circulation patterns. The polar radiative budget is sensitive to sea-ice loss and consequent surface albedo changes. Aerosols and polar cloud microphysics are crucial players in the radioactive energy balance of the Arctic Ocean. The main biogenic source of sulfate aerosols to the atmosphere above remote seas is dimethylsulfide (DMS). Recent research suggests the flux of DMS to the Arctic atmosphere may change markedly under global warming. This paper describes climate data and DMS production (based on the five years from 1998 to 2002) in the region of the Barents Sea (30–35°E and 70–80°N). A DMS model is introduced together with an updated calibration method. A genetic algorithm is used to calibrate the chlorophyll-a (CHL) measurements (based on satellite SeaWiFS data) and DMS content (determined from cruise data collected in the Arctic). Significant interannual variation of the CHL amount leads to significant interannual variability in the observed and modeled production of DMS in the study region. Strong DMS production in 1998 could have been caused by a large amount of ice algae being released in the southern region. Forcings from a general circulation model (CSIRO Mk3) were applied to the calibrated DMS model to predict the zonal mean sea-to-air flux of DMS for contemporary and enhanced greenhouse conditions at 70–80°N. It was found that significantly decreasing ice coverage, increasing sea surface temperature and decreasing mixed-layer depth could lead to annual DMS flux increases of more than 100% by the time of equivalent CO2 tripling (the year 2080). This significant perturbation in the aerosol climate could have a large impact on the regional Arctic heat budget and consequences for global warming.

关键词： Arctic Ocean dimethyl sulfide mixed-layer depth chlorophyll-a dimethyl sulfoniopropionate