目的从基因组水平探讨BEP2D辐射致癌模型中MTAP基因表达降低的原因。方法培养和传代BEP2D和BERP35T-2细胞,提取基因组DNA;设计针对MTAP基因8个外显子的引物,PCR扩增方式观察MTAP有无纯合性缺失,并对PCR产物进行SSCP分析;选择9p21.3区的...目的从基因组水平探讨BEP2D辐射致癌模型中MTAP基因表达降低的原因。方法培养和传代BEP2D和BERP35T-2细胞,提取基因组DNA;设计针对MTAP基因8个外显子的引物,PCR扩增方式观察MTAP有无纯合性缺失,并对PCR产物进行SSCP分析;选择9p21.3区的三个STS位点,PCR扩增分析该区域杂合性缺失的状况;设计针对MTAP基因CpG岛的MSP(Methylation-specified PCR甲基化特异性)引物,对基因组DNA进行硫化处理和纯化,PCR扩增以研究MTAP基因区域的杂合性缺失现象。结果在细胞中MTAP基因没有发生纯合性缺失和点突变,启动子区域亦没有甲基化调节现象;BERP35T-2细胞有杂合型缺失(Loss of Heterodeletion,LOH)现象,发生位置在RH99034。结论在致癌模型中MTAP基因的表达降低或丧失是因为MTAP所在的基因组区域发生了杂合性缺失,提示9p21.3区域的杂合性缺失可能是肺癌中发生的高频率事件。展开更多
AIM：To evaluate the methylation status of CDH1, FHIT, MTAP and PLAGL1 promoters and the association of these findings with clinico-pathological characteristics.METHODS： Methylation-specific PCR （MSP） assay was per...AIM：To evaluate the methylation status of CDH1, FHIT, MTAP and PLAGL1 promoters and the association of these findings with clinico-pathological characteristics.METHODS： Methylation-specific PCR （MSP） assay was performed in 13 nonneoplastic gastric adenocarcinorna, 30 intestinal-type gastric adenocarcinorna and 35 diffuse-type gastric adenocarcinorna samples from individuals in Northern Brazil. Statistical analyses were performed using the chi-square or Fisher＇s exact test to assess associations between rnethylation status and clinico-pathological characteristics.RESULTS： Hypermethylation frequencies of CDH1, FHIT, MTAPand PLAGL1 promoter were 98.7%, 53.9%, 23.1% and 29.5%, respectively. Hyperrnethylation of three or four genes revealed a significant association with diffuse-type gastric cancer compared with nonneoplastic cancer. A higher hyperrnethylation frequency was significantly associated with H pylori infection in gastric cancers, especially with diffuse-type. Cancer samples without lymph node metastasis showed a higher FHIT hypermethylation frequency. MTAP hypermethylation was associated with H pylori in gastric cancer samples, as well as with diffuse-type compared with intestinal-type. In diffuse-type, MTAP hypermethylation was associated with female gender.CONCLUSION： Our findings show differential gene methylation in tumoral tissue, which allows us to conclude that hypermethylation is associated with gastric carcinogenesis. MTAP promoter hypermethylation can be characterized as a marker of diffuse-type gastric cancer, especially in women and may help in diagnosis, prognosis and therapies. The H pylori infectious agent was present in 44.9% of the samples. This infection may be correlated with the carcinogenic process through the gene promoter hypermethylation, especially the MTAP promoter in diffuse-type. A higher H pylori infection in diffuse-type may be due to greater genetic predisposition.展开更多
针对恶劣海况下吊装细长杆件产生的双摆现象而带来的作业效率低、风险高以及难以精确定位等问题,提出了一种新型多柔索减摇定姿系统(multi-tagline anti-swing and positioning system,MTAPS),采用多体动力学和牛顿经典力学方法建立MTAP...针对恶劣海况下吊装细长杆件产生的双摆现象而带来的作业效率低、风险高以及难以精确定位等问题,提出了一种新型多柔索减摇定姿系统(multi-tagline anti-swing and positioning system,MTAPS),采用多体动力学和牛顿经典力学方法建立MTAPS的动力学模型。试验数据表明,MTAPS可以有效抑制规则吊重和细长杆件吊重的摆动,在短时间内可使细长杆件吊重趋于相对稳定状态,在设定工况下MTAPS对规则吊重和细长杆件的平均减摇比分别在90%和85%以上。通过动力学仿真分析比较了船舶运动激励下多柔索减摇系统和MTAPS的减摇效果以及动力学特性。基于多柔索减摇系统研制的起重机防摆装置已完成实船应用,为实现海上细长杆件的快速转运和精确定位提供了一种新思路。展开更多
To solve the design problem of transformer composed of non-resonant structure in ultrasonic gear-honing, force coupling conditions for moderately thick annular plate （MTAP） and catenary horn are proposed, and the fr...To solve the design problem of transformer composed of non-resonant structure in ultrasonic gear-honing, force coupling conditions for moderately thick annular plate （MTAP） and catenary horn are proposed, and the frequency equations of the transformer, which consist of an MTAP and a catenary horn, are derived based on Mindlin＇s theory. The design parameters of the transformer were obtained by solving the frequency equations with the help of MATLAB, and its mode and frequency were deduced by the modal analysis of finite element method （FEM）, which are consistent with the theoretical design demands. The transformer design can be extended from system with thin annular plate to that with MTAP as the theoretical method by the simulation analysis of various ratios of the thickness to radius.展开更多
Mesothelioma is a rare malignant tumor of the serosal membranes that can be challenging to diagnose,especially on small biopsy specimens.There are updated guidelines on the diagnosis and classification of mesothelioma...Mesothelioma is a rare malignant tumor of the serosal membranes that can be challenging to diagnose,especially on small biopsy specimens.There are updated guidelines on the diagnosis and classification of mesothelioma,which incorporate advancements in understanding mesothelioma biology published in the literature over recent years.This review will discuss marked developments and/or improvements that have been made,including:(1)to the histologic classifications of mesothelioma;(2)the use of such classifications and nuclear grading in prognosis;(3)the indispensability of ancillary studies in the diagnosis of mesothelioma;(4)the application of these pleural based classifications and diagnostic schemes in peritoneal mesothelioma;and(5)the potential for diagnosis of mesothelioma in situ.展开更多
文摘目的从基因组水平探讨BEP2D辐射致癌模型中MTAP基因表达降低的原因。方法培养和传代BEP2D和BERP35T-2细胞,提取基因组DNA;设计针对MTAP基因8个外显子的引物,PCR扩增方式观察MTAP有无纯合性缺失,并对PCR产物进行SSCP分析;选择9p21.3区的三个STS位点,PCR扩增分析该区域杂合性缺失的状况;设计针对MTAP基因CpG岛的MSP(Methylation-specified PCR甲基化特异性)引物,对基因组DNA进行硫化处理和纯化,PCR扩增以研究MTAP基因区域的杂合性缺失现象。结果在细胞中MTAP基因没有发生纯合性缺失和点突变,启动子区域亦没有甲基化调节现象;BERP35T-2细胞有杂合型缺失(Loss of Heterodeletion,LOH)现象,发生位置在RH99034。结论在致癌模型中MTAP基因的表达降低或丧失是因为MTAP所在的基因组区域发生了杂合性缺失,提示9p21.3区域的杂合性缺失可能是肺癌中发生的高频率事件。
基金Supported by Fundao de Amparo à Pesquisa do Estado de So Paulo, Coordenao de Aperfeioamento de Pessoal de Nível Superior and Conselho Nacional de Desenvolvimento Científico e Tecnológico
文摘AIM：To evaluate the methylation status of CDH1, FHIT, MTAP and PLAGL1 promoters and the association of these findings with clinico-pathological characteristics.METHODS： Methylation-specific PCR （MSP） assay was performed in 13 nonneoplastic gastric adenocarcinorna, 30 intestinal-type gastric adenocarcinorna and 35 diffuse-type gastric adenocarcinorna samples from individuals in Northern Brazil. Statistical analyses were performed using the chi-square or Fisher＇s exact test to assess associations between rnethylation status and clinico-pathological characteristics.RESULTS： Hypermethylation frequencies of CDH1, FHIT, MTAPand PLAGL1 promoter were 98.7%, 53.9%, 23.1% and 29.5%, respectively. Hyperrnethylation of three or four genes revealed a significant association with diffuse-type gastric cancer compared with nonneoplastic cancer. A higher hyperrnethylation frequency was significantly associated with H pylori infection in gastric cancers, especially with diffuse-type. Cancer samples without lymph node metastasis showed a higher FHIT hypermethylation frequency. MTAP hypermethylation was associated with H pylori in gastric cancer samples, as well as with diffuse-type compared with intestinal-type. In diffuse-type, MTAP hypermethylation was associated with female gender.CONCLUSION： Our findings show differential gene methylation in tumoral tissue, which allows us to conclude that hypermethylation is associated with gastric carcinogenesis. MTAP promoter hypermethylation can be characterized as a marker of diffuse-type gastric cancer, especially in women and may help in diagnosis, prognosis and therapies. The H pylori infectious agent was present in 44.9% of the samples. This infection may be correlated with the carcinogenic process through the gene promoter hypermethylation, especially the MTAP promoter in diffuse-type. A higher H pylori infection in diffuse-type may be due to greater genetic predisposition.
文摘针对恶劣海况下吊装细长杆件产生的双摆现象而带来的作业效率低、风险高以及难以精确定位等问题,提出了一种新型多柔索减摇定姿系统(multi-tagline anti-swing and positioning system,MTAPS),采用多体动力学和牛顿经典力学方法建立MTAPS的动力学模型。试验数据表明,MTAPS可以有效抑制规则吊重和细长杆件吊重的摆动,在短时间内可使细长杆件吊重趋于相对稳定状态,在设定工况下MTAPS对规则吊重和细长杆件的平均减摇比分别在90%和85%以上。通过动力学仿真分析比较了船舶运动激励下多柔索减摇系统和MTAPS的减摇效果以及动力学特性。基于多柔索减摇系统研制的起重机防摆装置已完成实船应用,为实现海上细长杆件的快速转运和精确定位提供了一种新思路。
基金Supported by the National Natural Science Foundation of China (50975191)the Innovation and Entrepreneurial Projects for College Students of Taiyuan (110148050)
文摘To solve the design problem of transformer composed of non-resonant structure in ultrasonic gear-honing, force coupling conditions for moderately thick annular plate （MTAP） and catenary horn are proposed, and the frequency equations of the transformer, which consist of an MTAP and a catenary horn, are derived based on Mindlin＇s theory. The design parameters of the transformer were obtained by solving the frequency equations with the help of MATLAB, and its mode and frequency were deduced by the modal analysis of finite element method （FEM）, which are consistent with the theoretical design demands. The transformer design can be extended from system with thin annular plate to that with MTAP as the theoretical method by the simulation analysis of various ratios of the thickness to radius.
文摘Mesothelioma is a rare malignant tumor of the serosal membranes that can be challenging to diagnose,especially on small biopsy specimens.There are updated guidelines on the diagnosis and classification of mesothelioma,which incorporate advancements in understanding mesothelioma biology published in the literature over recent years.This review will discuss marked developments and/or improvements that have been made,including:(1)to the histologic classifications of mesothelioma;(2)the use of such classifications and nuclear grading in prognosis;(3)the indispensability of ancillary studies in the diagnosis of mesothelioma;(4)the application of these pleural based classifications and diagnostic schemes in peritoneal mesothelioma;and(5)the potential for diagnosis of mesothelioma in situ.
