Multivariate statistical process monitoring and control (MSPM&C) methods for chemical process monitoring with statistical projection techniques such as principal component analysis (PCA) and partial least squares ...Multivariate statistical process monitoring and control (MSPM&C) methods for chemical process monitoring with statistical projection techniques such as principal component analysis (PCA) and partial least squares (PLS) are surveyed in this paper. The four-step procedure of performing MSPM&C for chemical process, modeling of processes, detecting abnormal events or faults, identifying the variable(s) responsible for the faults and diagnosing the source cause for the abnormal behavior, is analyzed. Several main research directions of MSPM&C reported in the literature are discussed, such as multi-way principal component analysis (MPCA) for batch process, statistical monitoring and control for nonlinear process, dynamic PCA and dynamic PLS, and on-line quality control by inferential models. Industrial applications of MSPM&C to several typical chemical processes, such as chemical reactor, distillation column, polymerization process, petroleum refinery units, are summarized. Finally, some concluding remarks and future considerations are made.展开更多
AIM: To determine the frequencies of HGV and TTV infections in blood donors in Hangzhou. METHODS: RT-nested PCR for HGV RNA detection and semi-nested PCR for TTV DNA detection in the sera from 203 blood donors, and nu...AIM: To determine the frequencies of HGV and TTV infections in blood donors in Hangzhou. METHODS: RT-nested PCR for HGV RNA detection and semi-nested PCR for TTV DNA detection in the sera from 203 blood donors, and nucleotide sequence analysis were performed. RESULTS: Thirty-two (15.8%) and 30 (14.8%) of the 203 serum samples were positive for HGV RNA and TTV DNA, respectively. And 5 (2.5%) of the 203 serum samples were detectable for both HGV RNA and TTV DNA. Homology of the nucleotide sequences of HGV RT-nested PCR products and TTV semi-nested PCR products from 3 serum samples compared with the reported HGV and TTV sequences was 89.36%, 87.94%, 88.65% and 63.51%, 65.77% and 67.12%, respectively. CONCLUSION: The infection rates of HGV and/or TTV in blood donors are relatively high, and to establish HGV and TTV examinations to screen blood donors is needed for transfusion security. The genomic heterogeneity of TTV or HGV is present in the isolates from different areas.展开更多
目的:探讨大鼠精原细胞的分离纯化. 方法:采用酶消化法制备10 d Wister大鼠睾丸单细胞悬液;Percoll液不连续密度梯度分离精原细胞;用贴壁速度的差异纯化精原细胞.光电镜观察精原细胞的形态结构特征;应用酪氨酸蛋白激酶(c-kit)免疫化学...目的:探讨大鼠精原细胞的分离纯化. 方法:采用酶消化法制备10 d Wister大鼠睾丸单细胞悬液;Percoll液不连续密度梯度分离精原细胞;用贴壁速度的差异纯化精原细胞.光电镜观察精原细胞的形态结构特征;应用酪氨酸蛋白激酶(c-kit)免疫化学鉴定精原细胞. 结果:精原细胞主要分布在28%～36%(Ⅱ带)间的Percoll梯度;分离纯化的精原细胞形态结构与组织切片上精原细胞一致,其纯度达55.68%;c-kit在精原细胞呈阳性表达,在睾丸体细胞呈弱阳性或阴性表达.结论:利用酶消化法、Percoll液不连续密度梯度及细胞贴壁速度的差异,分离纯化的精原细胞满足体外实验要求;精原细胞表达特异的c-kit受体.展开更多
Hepatitis C virus(HCV)infection is highly prevalent among patients on hemodialysis(HD).The prevalence of HCV infection in HD patients varies markedly from country to country.Some factors are especially related to thes...Hepatitis C virus(HCV)infection is highly prevalent among patients on hemodialysis(HD).The prevalence of HCV infection in HD patients varies markedly from country to country.Some factors are especially related to these high prevalence rates,such as blood transfusions and length of dialysis time. Nosocomial routes of transmission including the use of contaminated equipment and patient-to-patient exposure is considered more important.Several prophylactic measures have been suggested to avoid infection by HCV in the HD environment.展开更多
INTRODUCTIONHelicobacter pylori (H . pylori) is associated with the development of chronic gastritis ,peptic ulcer and gastric cancer and gastric MALT lymphoma[1-9],H .pylori has many antigens ,including urease ,heat ...INTRODUCTIONHelicobacter pylori (H . pylori) is associated with the development of chronic gastritis ,peptic ulcer and gastric cancer and gastric MALT lymphoma[1-9],H .pylori has many antigens ,including urease ,heat shock protein and vacuolating cytotoxin and so on ,and urease is an important factor in the colinization of the gastric mucosa and suspected to cause damage to the gastric mucosa[10-14].At the same time ,urdase is also one of the important protective antigens .展开更多
基金Supported by the National High-Tech Development Program of China(No.863-511-920-011,2001AA411230).
文摘Multivariate statistical process monitoring and control (MSPM&C) methods for chemical process monitoring with statistical projection techniques such as principal component analysis (PCA) and partial least squares (PLS) are surveyed in this paper. The four-step procedure of performing MSPM&C for chemical process, modeling of processes, detecting abnormal events or faults, identifying the variable(s) responsible for the faults and diagnosing the source cause for the abnormal behavior, is analyzed. Several main research directions of MSPM&C reported in the literature are discussed, such as multi-way principal component analysis (MPCA) for batch process, statistical monitoring and control for nonlinear process, dynamic PCA and dynamic PLS, and on-line quality control by inferential models. Industrial applications of MSPM&C to several typical chemical processes, such as chemical reactor, distillation column, polymerization process, petroleum refinery units, are summarized. Finally, some concluding remarks and future considerations are made.
文摘AIM: To determine the frequencies of HGV and TTV infections in blood donors in Hangzhou. METHODS: RT-nested PCR for HGV RNA detection and semi-nested PCR for TTV DNA detection in the sera from 203 blood donors, and nucleotide sequence analysis were performed. RESULTS: Thirty-two (15.8%) and 30 (14.8%) of the 203 serum samples were positive for HGV RNA and TTV DNA, respectively. And 5 (2.5%) of the 203 serum samples were detectable for both HGV RNA and TTV DNA. Homology of the nucleotide sequences of HGV RT-nested PCR products and TTV semi-nested PCR products from 3 serum samples compared with the reported HGV and TTV sequences was 89.36%, 87.94%, 88.65% and 63.51%, 65.77% and 67.12%, respectively. CONCLUSION: The infection rates of HGV and/or TTV in blood donors are relatively high, and to establish HGV and TTV examinations to screen blood donors is needed for transfusion security. The genomic heterogeneity of TTV or HGV is present in the isolates from different areas.
文摘目的:探讨大鼠精原细胞的分离纯化. 方法:采用酶消化法制备10 d Wister大鼠睾丸单细胞悬液;Percoll液不连续密度梯度分离精原细胞;用贴壁速度的差异纯化精原细胞.光电镜观察精原细胞的形态结构特征;应用酪氨酸蛋白激酶(c-kit)免疫化学鉴定精原细胞. 结果:精原细胞主要分布在28%～36%(Ⅱ带)间的Percoll梯度;分离纯化的精原细胞形态结构与组织切片上精原细胞一致,其纯度达55.68%;c-kit在精原细胞呈阳性表达,在睾丸体细胞呈弱阳性或阴性表达.结论:利用酶消化法、Percoll液不连续密度梯度及细胞贴壁速度的差异,分离纯化的精原细胞满足体外实验要求;精原细胞表达特异的c-kit受体.
文摘Hepatitis C virus(HCV)infection is highly prevalent among patients on hemodialysis(HD).The prevalence of HCV infection in HD patients varies markedly from country to country.Some factors are especially related to these high prevalence rates,such as blood transfusions and length of dialysis time. Nosocomial routes of transmission including the use of contaminated equipment and patient-to-patient exposure is considered more important.Several prophylactic measures have been suggested to avoid infection by HCV in the HD environment.
基金Supported by the National Major Science and Technology Projects,No.96-901-01-54.
文摘INTRODUCTIONHelicobacter pylori (H . pylori) is associated with the development of chronic gastritis ,peptic ulcer and gastric cancer and gastric MALT lymphoma[1-9],H .pylori has many antigens ,including urease ,heat shock protein and vacuolating cytotoxin and so on ,and urease is an important factor in the colinization of the gastric mucosa and suspected to cause damage to the gastric mucosa[10-14].At the same time ,urdase is also one of the important protective antigens .
