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串联质谱技术在遗传性代谢病高危儿童筛查中的初步应用 被引量:142
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作者 顾学范 韩连书 +3 位作者 高晓岚 杨艳玲 叶军 邱文娟 《中华儿科杂志》 CAS CSCD 北大核心 2004年第6期401-404,F001,F002,共6页
目的 开展遗传性代谢病高危儿童筛查检测。方法 临床疑诊遗传性代谢病儿童 10 4例 ,男 77例 ,女 2 7例 ,年龄 (4 8± 4 2 )岁。手指采血 ,滴于专用采血滤纸上。干血滤纸片与含已知量的氨基酸、酰基肉碱同位素内标一起 ,经甲醇萃... 目的 开展遗传性代谢病高危儿童筛查检测。方法 临床疑诊遗传性代谢病儿童 10 4例 ,男 77例 ,女 2 7例 ,年龄 (4 8± 4 2 )岁。手指采血 ,滴于专用采血滤纸上。干血滤纸片与含已知量的氨基酸、酰基肉碱同位素内标一起 ,经甲醇萃取 ,盐酸正丁醇衍生后 ,用串联质谱仪分析血片中氨基酸谱和酰基肉碱谱及其浓度。结果 在 10 4例标本中 ,检出阳性标本 10例 (9 6 % ) ,其中酪氨酸血症1例 ,同型胱氨酸血症 1例 ,高鸟氨酸血症 1例 ,甲基丙二酸血症 2例 ,丙酸血症 1例 ,3 羟基 3 甲基戊二酸裂解酶缺乏症 1例 ,中链酰基辅酶A脱氢酶缺乏症 2例 ,酰基肉碱转移酶Ⅱ缺乏症 1例。结论串联质谱技术可检测 30余种遗传性代谢病 ,包括氨基酸代谢紊乱、有机酸代谢紊乱和脂肪酸代谢紊乱性疾病 。 展开更多
关键词 串联质谱技术 遗传性代谢病 高危儿童 筛查 酪氨酸血症 3-羟基3-甲基戊二酸裂解酶缺乏症
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The Hoeke-Brown failure criterion and GSI-2018 edition 被引量:112
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作者 E.Hoek E.T.Brown 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2019年第3期445-463,共19页
The HoekeBrown criterion was introduced in 1980 to provide input for the design of underground excavations in rock.The criterion now incorporates both intact rock and discontinuities,such as joints,characterized by th... The HoekeBrown criterion was introduced in 1980 to provide input for the design of underground excavations in rock.The criterion now incorporates both intact rock and discontinuities,such as joints,characterized by the geological strength index(GSI),into a system designed to estimate the mechanical behaviour of typical rock masses encountered in tunnels,slopes and foundations.The strength and deformation properties of intact rock,derived from laboratory tests,are reduced based on the properties of discontinuities in the rock mass.The nonlinear HoekeBrown criterion for rock masses is widely accepted and has been applied in many projects around the world.While,in general,it has been found to provide satisfactory estimates,there are several questions on the limits of its applicability and on the inaccuracies related to the quality of the input data.This paper introduces relatively few fundamental changes,but it does discuss many of the issues of utilization and presents case histories to demonstrate practical applications of the criterion and the GSI system. 展开更多
关键词 HOEK-BROWN criterion Geological STRENGTH index(GSI) ROCK mass STRENGTH Uniaxial compressive strength(UCS) Tension cut-off ROCK mass deformation modulus
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我国群众性羽毛球运动现状与对策研究 被引量:95
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作者 傅小惠 王佳宾 张林 《成都体育学院学报》 CSSCI 北大核心 2008年第4期47-50,共4页
羽毛球运动在我国有普遍的群众基础。通过对目前我国群众性羽毛球运动现状的调查,分析其存在的主要问题,提出相应的对策与建议,为今后更好地开展这一运动提供理论依据和实践指导。
关键词 群众性 羽毛球 现状 对策
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当代中国政治语境中的“群众”概念分析 被引量:87
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作者 丛日云 《政法论坛》 CSSCI 北大核心 2005年第2期15-24,共10页
当代中国政治话语中的“群众”概念是传统文化中的“民”(或“臣民”)与西方民主理论中的“人民”相嫁接后 ,安顿在传统术语“群众”的外壳之中而形成的。同时 ,它也是西方群众理论在中国的变异 ,特别是对群众价值评判彻底颠覆的产物。... 当代中国政治话语中的“群众”概念是传统文化中的“民”(或“臣民”)与西方民主理论中的“人民”相嫁接后 ,安顿在传统术语“群众”的外壳之中而形成的。同时 ,它也是西方群众理论在中国的变异 ,特别是对群众价值评判彻底颠覆的产物。作为承载丰富的政治文化意蕴的符号 ,“群众”是“人民”的不彻底的具体化 ,是“臣民”向“公民”的过渡环节。一方面 ,它超越了传统的臣民 ,但仍然承袭了臣民概念的某些内涵 ;另一方面 ,它也涵蕴着公民概念的某些要素 ,但还不是真正意义上的公民。 展开更多
关键词 群众 人民 公民 臣民
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Colorectal cancer: From prevention to personalized medicine 被引量:72
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作者 Gemma Binefa Francisco Rodríguez-Moranta +1 位作者 àlex Teule Manuel Medina-Hayas 《World Journal of Gastroenterology》 SCIE CAS 2014年第22期6786-6808,共23页
Colorectal cancer(CRC)is a very heterogeneous disease that is caused by the interaction of genetic and environmental factors.CRC develops through a gradual accumulation of genetic and epigenetic changes,leading to the... Colorectal cancer(CRC)is a very heterogeneous disease that is caused by the interaction of genetic and environmental factors.CRC develops through a gradual accumulation of genetic and epigenetic changes,leading to the transformation of normal colonic mucosa into invasive cancer.CRC is one of the most prevalent and incident cancers worldwide,as well as one of the most deadly.Approximately 1235108 people are diagnosed annually with CRC,and 609051 die from CRC annually.The World Health Organization estimates an increase of77%in the number of newly diagnosed cases of CRCand an increase of 80%in deaths from CRC by 2030.The incidence of CRC can benefit from different strategies depending on its stage:health promotion through health education campaigns(when the disease is not yet present),the implementation of screening programs(for detection of the disease in its early stages),and the development of nearly personalized treatments according to both patient characteristics(age,sex)and the cancer itself(gene expression).Although there are different strategies for screening and although the number of such strategies is increasing due to the potential of emerging technologies in molecular marker application,not all strategies meet the criteria required for screening tests in population programs;the three most accepted tests are the fecal occult blood test(FOBT),colonoscopy and sigmoidoscopy.FOBT is the most used method for CRC screening worldwide and is also the primary choice in most population-based screening programs in Europe.Due to its non-invasive nature and low cost,it is one of the most accepted techniques by population.CRC is a very heterogeneous disease,and with a few exceptions(APC,p53,KRAS),most of the genes involved in CRC are observed in a small percentage of cases.The design of genetic and epigenetic marker panels that are able to provide maximum coverage in the diagnosis of colorectal neoplasia seems a reasonable strategy.In recent years,the use of DNA,RNA and protein markers in different biological samples 展开更多
关键词 Colorectal cancer PREVENTION mass screening Biological markers Drug therapy
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Vaccination against hepatitis B: the Chinese experience 被引量:68
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作者 ZHOU Yi-hua WU Chao ZHUANG Hui 《Chinese Medical Journal》 SCIE CAS CSCD 2009年第1期98-102,共5页
Objective To review the implementation of mass vaccination of hepatitis B vaccine and its critical role in prevention of hepatitis B virus infection in China.Data sources The data were mainly from PubMed, China Hospit... Objective To review the implementation of mass vaccination of hepatitis B vaccine and its critical role in prevention of hepatitis B virus infection in China.Data sources The data were mainly from PubMed, China Hospital Knowledge Database, and other popular Chinese journals published from 1980 to 2008. The search term was "hepatitis B vaccine".Study selection Original studies conducted in China and critical reviews authored by principal investigators in the field of hepatology in China were selected.Results Chinese investigators started to develop hepatitis B vaccine in late 1970s. The first home-made plasma-derived vaccine became available in 1986, which has been completely replaced by the domestically produced recombinant (yeast or Chinese hamster ovary cell) vaccine since 2001. China health authority recommended vaccinating all infants in 1992. From then on, China has put tremendous efforts in implementation of mass vaccination. The overall coverage of hepatitis B vaccine in infants has increased steadily and reached more than 95.0% in urban and 83.0%-97.0% in rural areas. The chronic HBV carrier rate in children 〈10 years of age decreased from 10.0% before the mass vaccination to 1.0%-2.0% in 2006, and that in general population decreased from 10.0% to 7.2%; overall, the nationwide mass hepatitis B vaccination has reduced more than 30 million of chronic HBV infections and HBV related severe sequlae.Conclusion The Chinese successful experience in control of hepatitis B by mass vaccination offers an example for any unindustrialized country whoever is committed to control this disease. 展开更多
关键词 hepatitis B virus VACCINE mass immunization reduced prevalence
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高等教育大众化的制度变迁与路径选择 被引量:54
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作者 冯向 《高等教育研究》 CSSCI 北大核心 2004年第3期30-34,共5页
高等教育毛入学率达到某一阈限时,高等教育系统的状态会发生重大的变化。要顺利地推进高等教育大众化,必须建立与大众化入学人数相适应的、符合本国国情的高等教育体系和制度。我们面临着规模的快速扩张与体系制度变革滞后的矛盾,必须... 高等教育毛入学率达到某一阈限时,高等教育系统的状态会发生重大的变化。要顺利地推进高等教育大众化,必须建立与大众化入学人数相适应的、符合本国国情的高等教育体系和制度。我们面临着规模的快速扩张与体系制度变革滞后的矛盾,必须打破制度变迁对原有路径的依赖,从"单一化路径"转向"多元化路径"。"多元化路径"的制度安排重点,是培育形成多元的经费投入渠道和多元的调控力量和手段。 展开更多
关键词 高等教育 大众化 制度变革
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串联质谱技术在有机酸血症筛查中的应用研究 被引量:62
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作者 韩连书 高晓岚 +2 位作者 叶军 邱文娟 顾学范 《中华儿科杂志》 CAS CSCD 北大核心 2005年第5期325-330,共6页
目的探讨串联质谱技术在遗传性代谢病高危儿童有机酸血症筛查和诊断中的意义。方法遗传性代谢病高危儿童1000例,男642例,女358例,年龄中位数为2岁(5天~15岁),手指采血,滴于滤纸片上。取直径3mm的干血滤纸片放入96孔聚丙烯板,经含酰基... 目的探讨串联质谱技术在遗传性代谢病高危儿童有机酸血症筛查和诊断中的意义。方法遗传性代谢病高危儿童1000例,男642例,女358例,年龄中位数为2岁(5天~15岁),手指采血,滴于滤纸片上。取直径3mm的干血滤纸片放入96孔聚丙烯板,经含酰基肉碱内标的甲醇萃取,盐酸正丁醇衍生后,进行串联质谱分析。结果1000例高危儿童中筛查并诊断有机酸血症40例(4.0%),其中甲基丙二酸血症20例,丙酸血症6例,异戊酸血症3例,戊二酸血症Ⅰ型3例,戊二酸血症Ⅱ型3例,3甲基巴豆酰辅酶A羧化酶缺乏症1例,3羟基3甲基戊二酰辅酶A裂解酶缺乏症1例,生物素酶缺乏症2例,β酮硫解酶缺乏症1例。患儿临床表现主要为运动和智力发育落后、抽搐、意识障碍、肌张力低下、呕吐和喂养困难等。常规实验室检查主要表现为酸中毒、高血氨、高乳酸血症和低血糖等。结论串联质谱技术能够通过检测血滤纸片中的不同酰基肉碱浓度,对部分有机酸血症进行快速筛查和诊断,结合尿气相色谱/质谱技术,有助于提高有机酸血症诊断的准确性。 展开更多
关键词 串联质谱技术 有机酸血症 遗传性代谢病 甲基丙二酸血症 生物素酶缺乏症 高危儿童 肌张力低下 实验室检查 高乳酸血症 滤纸片 手指采血 质谱分析 丙酸血症 发育落后 临床表现 意识障碍 喂养困难 主要表现 肉碱浓度 快速筛查
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Effect of Body Mass Index on All-cause Mortality and Incidence of Cardiovascular Diseases─Report for Meta-Analysis of Prospective Studies on Optimal Cut-off Points of Body Mass Index in Chinese Adults 被引量:58
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作者 ZHOU BEI-FAN 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2002年第3期245-252,共8页
Objective To verify the optimal cut-off points for overweight and obesity in Chinese adults based on the relationship of baseline body mass index (BMI) to all-cause mortality, and incidence of cardiovascular diseases... Objective To verify the optimal cut-off points for overweight and obesity in Chinese adults based on the relationship of baseline body mass index (BMI) to all-cause mortality, and incidence of cardiovascular diseases from pooled data of Chinese cohorts. Methods The prospective study data of existing cohort studies in China were collected, and the age-adjusted all-cause mortality stratified by BMI were estimated. The similar analysis was repeated after excluding deaths within the first three years of follow-up and after excluding smokers. The incidence of age-adjusted coronary heart disease (CHD) and stroke stratified by BMI were also analyzed. Multiple Cox regression coefficients of BMI for the incidence of CHD and stroke after controlling other risk factors were pooled utilizing the methods of weighting by inverse of variance to reveal whether BMI had independent effect and its strength on the incidence of CHD and stroke. Results The data of 4 cohorts including 76 227 persons, with 745 346 person-years of follow-up were collected and analyzed. The age-adjusted all-cause mortality stratified by BMI showed a U-shaped curve, even after excluding deaths within the first three years of follow-up and excluding smokers. Age-adjusted all-cause mortality increased when BMI was lower than 18.5 and higher than 28. The incidence of CHD and stroke, especially ishemic stroke increased with increasing BMI, this was consistent with parallel increasing of risk factors. Cox regression analysis showed that BMI was an independent risk factor for both CHD and stroke. Each amount of 2 kg/m2 increase in baseline BMI might cause 15.4%, 6.1% and 18.8 % increase in relative risk of CHD, total stroke and ischemic stroke. Reduction of BMI to under 24 might prevent the incidence of CHD by 11% and that of stroke by 15 % for men, and 22 % of both diseases for women. Conclusion BMI ≤18.5, 24-27.9 and ≥28 (kg/m2) is the appropriate cut-off points for underweight, overweight and obesity in Chinese adults. 展开更多
关键词 Body mass index (BMI) All-cause mortality Coronary heart disease STROKE
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Report on Childhood Obesity in China (1) Body Mass Index Reference for Screening Overweight and Obesity in Chinese School-age Children 被引量:57
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作者 COOPERATIVE STUDY ON CHILDHOOD OBESITY WORKING GROUP ON OBESITY IN CHINA (WGOC) 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2005年第6期390-400,共11页
Purpose To establish and propose a national body mass index (BMI) reference for screening overweight and obesity in Chinese school-age children and adolescents. Methods 2000 CNSSCH (Chinese National Survey on Stude... Purpose To establish and propose a national body mass index (BMI) reference for screening overweight and obesity in Chinese school-age children and adolescents. Methods 2000 CNSSCH (Chinese National Survey on Students Constitution and Health) data, including 216 620 primary and secondary school students aged 7 to 18 years old, were used as a reference population. Compared with those of the NCHS intematioanl reference, three temporary sets of cut-off BMI were proposed by testing different combinations of P85, P90, and P95. When physiological and biochemical measures between and among “obesity” “overweight”, and “normal weight” groups were taken into consideration, set Ⅱ was selected to be the most appropriate one. The sex-age-specific curves were then plotted and smoothed by using B-spline method. Results Based on the samples from costal developed metropolis, the BMI curves successfully overcame the shortcomings of lower and level-off tendency of the Chinese total population. Temporary set H, composed by cut-offs of P85 for overweight and P95 for obesity, was finally selected by its sensitivity and peculiarity. BMI 24 and 28 were used as cut-offs for overweight and obesity for both males and females aged 18 years old. These cut-offs, consistent with Chinese Adult's Reference, was proposed as the Body mass index reference for screening overweight and obesity in Chinese school-age children and adolescents. Conehlsion The new reference clearly showed its superiorty in both prospectivity and actuality. The proposed reference minimized the gaps of the BMI curve between Chinese adolescents and the international reference. Most importantly was that it was consistent with the Eastern Asia ethnic characteristics of body fatness growth. It was therefore proposed by the Working Group on Obesity in China (WGOC) to use it as an nationwide reference for screening overweight and obesity of school-age children and adolescents in China. 展开更多
关键词 Body mass index Chinese school-age children OVERWEIGHT REFERENCE
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Prediction of Abdominal Visceral Obesity From Body Mass Index,Waist Circumference and Waist-hip Ratio in Chinese Adults:Receiver Operating Characteristic Curves Analysis 被引量:54
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作者 WEI-PINGJIA JUN-XILU +3 位作者 KUN-SANXIANG Yu-QIANBAO HUI-JUANLU ANDLEICHEN 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2003年第3期206-211,共6页
Objective To evaluate the sensitivity and specificity of body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) measurements in diagnosing abdominal visceral obesity. Methods BMI, WC, and WHR wer... Objective To evaluate the sensitivity and specificity of body mass index (BMI), waist circumference (WC) and waist-to-hip ratio (WHR) measurements in diagnosing abdominal visceral obesity. Methods BMI, WC, and WHR were assessed in 690 Chinese adults (305 men and 385 women) and compared with magnetic resonance imaging (MRI) measurements of abdominal visceral adipose tissue (VA). Receiver operating characteristic (ROC) curves were generated and used to determine the threshold point for each anthropometric parameter. Results 1) MRI showed that 61.7% of overweight/obese individuals (BMI≥25 kg/m2) and 14.2% of normal weight (BMI<25 kg/m2) individuals had abdominal visceral obesity (VA≥100 cm2). 2) VA was positively correlated with each anthropometric variable, of which WC showed the highest correlation (r=0.73-0.77, P<0.001). 3) The best cut-off points for assessing abdominal visceral obesity were as followed: BMI of 26 kg/m2, WC of 90 cm, and WHR of 0.93, with WC being the most sensitive and specific factor. 4) Among subjects with BMI≥28 kg/m2 or WC≥95 cm, 95% of men and 90% of women appeared to have abdominal visceral obesity. Conclusion Measurements of BMI, WC, and WHR can be used in the prediction of abdominal visceral obesity, of which WC was the one with better accuracy. 展开更多
关键词 Body mass index (BMI) Abdominal visceral fat Anthropometric parameters Receiver operating characteristic (ROC) curves
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Progress in study on constructal theory and its applications 被引量:52
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作者 CHEN LinGen 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第3期802-820,共19页
The emergence and development of constructal theory,which has been a new discipline branch to research sorts of structures in nature and engineering,are reviewed.The core of the constructal theory is that various shap... The emergence and development of constructal theory,which has been a new discipline branch to research sorts of structures in nature and engineering,are reviewed.The core of the constructal theory is that various shapes and structures of the matters in nature are generated from the tendency to obtain optimal performance.Constructal theory and its application are summarized,from disciplines such as heat,mechanism,fluid flow,electricity,magnetism and chemistry,to life and non-life systems in nature. 展开更多
关键词 constructal theory generalized thermodynamic optimization 'volume-point' model heat transfer heat and mass trans-fer fluid flow transport engineering
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薄板冷轧厚度与板形高精度控制技术 被引量:35
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作者 许健勇 《钢铁》 CAS CSCD 北大核心 2002年第1期73-77,18,共6页
介绍与分析目前最新薄板冷轧厚度控制技术 Mass Flow AGC及激光直接测量带钢速度技术 ,厚度偏差可控制在厚度的± (0 .7%~ 0 .6 % )范围内。分析和比较目前冷轧主流机型及其板形控制技术 。
关键词 mass Flow AGC 横向刚度 凸度 边部减薄 神经网络 冷轧薄板 厚度控制 板形控制
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Endoscopic ultrasound elastography for evaluation of lymph nodes and pancreatic masses:A multicenter study 被引量:48
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作者 Marc Giovannini Botelberge Thomas +16 位作者 Bories Erwan Pesenti Christian Caillol Fabrice Esterni Benjamin Monges Geneviève Arcidiacono Paolo Deprez Pierre Yeung Robert Schimdt Walter Schrader Hanz Szymanski Carl Dietrich Christoph Eisendrath Pierre Van Laethem Jean-Luc Devière Jacques Vilmann Peter Saftoiu Andrian 《World Journal of Gastroenterology》 SCIE CAS CSCD 2009年第13期1587-1593,共7页
AIM:To evaluate the ability of endoscopic ultrasound(EUS) elastography to distinguish benign from malignant pancreatic masses and lymph nodes.METHODS:A multicenter study was conducted and included 222 patients who und... AIM:To evaluate the ability of endoscopic ultrasound(EUS) elastography to distinguish benign from malignant pancreatic masses and lymph nodes.METHODS:A multicenter study was conducted and included 222 patients who underwent EUS examination with assessment of a pancreatic mass(n=121) or lymph node(n=101).The classification as benign or malignant,based on the real time elastography pattern,was compared with the classif ication based on the B-mode EUS images and with the fi nal diagnosis obtained by EUS-guided fi ne needle aspiration(EUS-FNA) and/or by surgical pathology.An interobserver study was performed.RESULTS:The sensitivity and specificity of EUS elastography to differentiate benign from malignant pancreatic lesions are 92.3% and 80.0%,respectively,compared to 92.3% and 68.9%,respectively,for the conventional B-mode images.The sensitivity and specificity of EUS elastography to differentiate benign from malignant lymph nodes was 91.8% and 82.5%,respectively,compared to 78.6% and 50.0%,respectively,for the B-mode images.The kappa coefficient was 0.785 for the pancreatic masses and 0.657 for the lymph nodes.CONCLUSION:EUS elastography is superior compared to conventional B-mode imaging and appears to be able to distinguish benign from malignant pancreatic masses and lymph nodes with a high sensitivity,specificity and accuracy.It might be reserved as a second line examination to help characterise pancreatic masses after negative EUS-FNA and might increase the yield of EUS-FNA for lymph nodes. 展开更多
关键词 Endoscopic ultrasound Elasticity coefficient ELASTOGRAPHY Pancreatic mass Lymph node
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CASE-BASED PRODUCT CONFIGURATION AND REUSE IN MASS CUSTOMIZATION 被引量:40
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作者 Wang Shiwei Tan Jianrong +2 位作者 Zhang Shuyou Wang Xin He Chenqi State Key Laboratory of CAD&CG,Zhejiang University,Hangzhou 310027, China 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2004年第2期233-236,252,共5页
The increasing complexity and size of configuration knowledge bases requres the provisionof advanced methods supporting the development of the actual configuration process and design reuse.A new framework to find a fe... The increasing complexity and size of configuration knowledge bases requres the provisionof advanced methods supporting the development of the actual configuration process and design reuse.A new framework to find a feasible and practical product configuration method is presented in masscustomization. The basic idea of the appoach is to integrate case-based reasoning (CBR) with a con-straint satisfaction problem(CSP). The similarity measure between a crisp and range is also given,which is common in case retrieves. Based on the configuration model, a product platform and customerneeds, case adaptation is carried out with the repair-based algorithm. Lastly, the methodology in theelevator configuration design domain is tested. 展开更多
关键词 Case-based reasoning Product configuration mass customization REUSE
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液相色谱-串联质谱法测定饲料中14种霉菌毒素及其类似物 被引量:43
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作者 应永飞 朱聪英 +5 位作者 韦敏珏 陈慧华 屈健 陆春波 林仙军 罗成江 《分析化学》 SCIE EI CAS CSCD 北大核心 2010年第12期1759-1764,共6页
采用高效液相色谱-电喷雾串联质谱仪(LC-ESI-MS-MS),在多反应监测(MRM)模式下建立了饲料中玉米赤霉烯酮、黄曲霉毒素和单端孢霉烯族A类毒素等14种毒素及其类似物的快速确认测定方法。试样中的黄曲霉毒素、玉米赤霉烯酮和单端孢霉烯族A... 采用高效液相色谱-电喷雾串联质谱仪(LC-ESI-MS-MS),在多反应监测(MRM)模式下建立了饲料中玉米赤霉烯酮、黄曲霉毒素和单端孢霉烯族A类毒素等14种毒素及其类似物的快速确认测定方法。试样中的黄曲霉毒素、玉米赤霉烯酮和单端孢霉烯族A类毒素经乙腈-水(84:16,V/V)提取,正己烷脱脂及霉菌毒素多功能净化柱净化,氮气吹干,用1mL乙腈/水(1:1,V/V)定容后,进行液相色谱-串联质谱法测定,采用色谱保留时间和质谱碎片离子丰度比定性,外标法定量。采用正离子扫描和负离子扫描的方式进行仪器方法学研究,确定丰度比最高的2对离子作为监测离子,进行MRM模式定性定量分析。本方法的检出限(LOD)为0.1~0.8μg/kg;线性范围为2.0~200.0μg/L,相关系数r均大于0.999。在5.0~100μg/kg的添加水平上,上述14种霉菌毒素及其类似物的平均回收率为59.0%~107%;相对标准偏差为2.1%~12.6%。 展开更多
关键词 高效液相色谱 串联质谱法 测定 饲料 霉菌毒素 其类似物 mass Spectrometry 玉米赤霉烯酮 碎片离子 黄曲霉毒素 单端孢霉烯 相对标准偏差 色谱保留时间 类毒素 丰度比 方法学研究 定性定量分析 平均回收率 多反应监测 串联质谱仪
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奥陶纪-志留纪边界附近火山活动记录:来华南周缘钾质斑脱岩的信息 被引量:43
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作者 胡艳华 孙卫东 +3 位作者 丁兴 汪方跃 凌明星 刘健 《岩石学报》 SCIE EI CAS CSCD 北大核心 2009年第12期3298-3308,共11页
扬子地台内奥陶纪顶部的五峰组到志留纪底部的龙马溪组间存在着多个粘土岩层。前人研究结果认为这些粘土岩层为钾质斑脱岩,是火山喷发的凝灰质物质在海相环境沉积、蚀变的产物。这些斑脱岩广泛分布于扬子地台周缘,对理解奥陶纪-志留纪... 扬子地台内奥陶纪顶部的五峰组到志留纪底部的龙马溪组间存在着多个粘土岩层。前人研究结果认为这些粘土岩层为钾质斑脱岩,是火山喷发的凝灰质物质在海相环境沉积、蚀变的产物。这些斑脱岩广泛分布于扬子地台周缘,对理解奥陶纪-志留纪时华南所处的大地构造位置和相应的构造事件具有重要的意义。本文对采自扬子地台内湖北宜昌地区和贵州桐梓地区奥陶纪-志留纪界线剖面的斑脱岩层进行了矿物学及地球化学工作,旨在判定其形成的构造环境。矿物学研究表明上述岩石除了含有粘土矿物外,还含有石英、长石、黑云母、磷灰石、锆石等中酸性岩浆岩中的常见矿物,属典型的钾质斑脱岩。本文利用在风化过程中不活动元素对斑脱岩的原岩进行了恢复,结果也表明其原岩为中酸性火山岩,包括安山岩-英安岩-及流绞岩等。微量元素特征显示多数样品具有典型的岛弧火山岩的特征,很可能与北面早古生代秦岭洋的闭合过程中的板块俯冲有关,也可能是早古生代在华南板块东南缘外侧存在的一古老洋壳向华南板块的俯冲。有一个样品(YC0711)没有Nb的负异常,但是具有明显的Ti负异常,在Th/Yb-Nb/Yb判别图上落在岛弧区附近,其原岩可能是富铌玄武岩之类的特殊岛弧岩石。火山活动的峰期为晚奥陶世赫南特阶时代,与地质历史上第二大的生物大灭绝事件同时。前人认为该生物灭绝事件与冈瓦纳冰川有关。考虑到华南以及欧洲、北美等地均出现大规模晚奥陶世-早侏罗纪钾质斑脱岩,奥陶纪-志留纪边界的火山事件是具有全球规模的,所喷发的岩石多是富含挥发份的中酸性岩,对大气圈和生物圈具有十分重要的影响,本文认为火山活动很可能是造成晚奥陶世的生物大灭绝事件和冈瓦纳冰川的主要诱导因素。 展开更多
关键词 奥陶纪 志留纪 边界 火山活动 活动记录 华南板块 钾质斑脱岩 信息 Yangtze Block mass extinction VOLCANIC rocks 扬子地台 晚奥陶世 typical characteristics South China plate tectonic setting 事件 生物大灭绝 VOLCANIC activity geological events
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大尺寸柱状结构质量、质心测量方法 被引量:34
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作者 郑宾 侯文 杨瑞峰 《测试技术学报》 2002年第2期108-111,共4页
目的 讨论大尺寸柱状结构水雷质量、质心测量的理方法 .方法 采用三点测量法和四点测量法 .结果与结论 通过原理分析及不确定度评定 ,证明其方法的可行性 .
关键词 大尺寸柱状结构 测量 质量 质心 不确定度 水雷 三点测量法 四点测量法
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The compelling link between physical activity and the body's defense system 被引量:42
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作者 David C.Nieman Laurel M.Wentz 《Journal of Sport and Health Science》 SCIE 2019年第3期201-217,共17页
This review summarizes research discoveries within 4 areas of exercise immunology that have received the most attention from investigators :(1) acute and chronic effects of exercise on the immune system,(2) clinical b... This review summarizes research discoveries within 4 areas of exercise immunology that have received the most attention from investigators :(1) acute and chronic effects of exercise on the immune system,(2) clinical benefits of the exercise—immune relationship,(3) nutritional influen?ces on the immune response to exercise, and(4) the effect of exercise on immunosenescence. These scientific discoveries can be organized into distinctive time periods: 1900-1979, which focused on exercise-induced changes in basic immune cell counts and function; 1980-1989, during which seminal papers were published with evidence that heavy exertion was associated with transient immune dysfunction, elevated inflammatory biomarkers,and increased risk of upper respiratory tract infections; 1990-2009, when additional focus areas were added to the field of exercise immunology including the interactive effect of nutrition, effects on the aging immune system, and inflammatory cytokines; and 2010 to the present, when technological advances in mass spectrometry allowed system biology approaches(i.e., metabolomics, proteomics, lipidomics, and microbiome characterization) to be applied to exercise immunology studies. The future of exercise irmmunology will take advantage of these technologies to provide new insights on the interactions between exercise, nutrition, and immune function, with application down to the person?alized level. Additionally, these methodologies will improve mechanistic understanding of how exercise-induced immune perturbations reduce the risk of common chronic diseases. 展开更多
关键词 AGING EXERCISE IMMUNOLOGY INFECTION INFLAMMATION mass Snectrometry NUTRITION
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低剂量CT肺癌筛查中持续存在肺结节的CT体积和质量增长及其影响因素 被引量:43
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作者 孙琦 黄遥 +4 位作者 赵世俊 张丽 唐威 金玉晶 吴宁 《中华肿瘤杂志》 CAS CSCD 北大核心 2018年第4期274-279,共6页
目的评估低剂量螺旋CT肺癌筛查中持续存在肺结节的CT体积和质量的增长及其影响因素。方法回顾性分析2009年3月至2015年12月在中国医学科学院肿瘤医院行≥2次胸部低剂量CT筛查的受检者的CT图像,纳入结节的标准为平均径线≥6mm,将体积... 目的评估低剂量螺旋CT肺癌筛查中持续存在肺结节的CT体积和质量的增长及其影响因素。方法回顾性分析2009年3月至2015年12月在中国医学科学院肿瘤医院行≥2次胸部低剂量CT筛查的受检者的CT图像,纳入结节的标准为平均径线≥6mm,将体积增长定义为≥20%。在筛选出的51位受检者(男性26例,女性25例)中,符合条件的肺结节51个,其中非实性结节10个,部分实性结节17个,实性结节24个;高危风险组14个,中危风险组12个,低危风险组25个。应用肺结节分析软件自动测量结节的三维径线、体积和结节体积倍增时间(VDT),计算质量倍增时间(MDT)。结果在体积增长≥20%的51个结节中,平均径线增长≥1.5mm的结节33个,平均径线增长〈1.5mm的结节18个。部分实性结节的中位VDT为364d,低于非实性结节和实性结节(分别为761d和819d),差异均有统计学意义(均P〈0.05)。部分实性结节的中位MDT为351d,低于非实性结节和实性结节(分别为772d和840d),差异均有统计学意义(均P〈0.05)。高危风险组肺结节的中位VDT和MDT分别为181d和256d,均低于低危风险组(分别为1037d和l035d),差异均有统计学意义(均P〈0.05)。VDT与MDT具有相关性(r=0.909,P〈0.001)。结论肺结节的性质和受检者的风险状态均能影响结节的生长,部分实性结节和高危人群的结节生长相对较快,应密切关注。相对于二维径线,体现三维体积和质量变化的VDT和MDT为更早提示结节增长的量化指标。部分实性结节的质量变化早于体积变化。 展开更多
关键词 肺肿瘤 筛查 低剂量CT 体积 质量
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