Objective To investigate genomic variations of two Chinese Yersinia pestis isolates that were isolated from different plague foci obtained from vaccine strain EV76 from the Yunnan province of China. Methods A microarr...Objective To investigate genomic variations of two Chinese Yersinia pestis isolates that were isolated from different plague foci obtained from vaccine strain EV76 from the Yunnan province of China. Methods A microarray containing 12 000 probes covering the entire genome of seven Yersinie pestis and two Yersinia pseudotuberculosis strains, was used. PCR assays were performed to confirm microarray results. Results The gene variations detected included the absence of five genes related to the synthesis of betaine in both EV76 and another sequenced attenuated strain, KIM D27. Several genes related to phage-related membrane proteins were found to be absent in the Antiqua biovar Yunnan strain, 485, which was isolated from a rodent plague foci. Conclusion These findings provide initial insight into the distinct strains isolated from natural foci, within their genomic context, including Yunnan Y. pestis strains. This information will be used therefore to establish subsequent comparisons of these sequences with published complete genomes of other strains.展开更多
Yersinia pestis is the causative agent of bubonic and pneumonic plagues. Strains of Y. pestis are classified into four biovars： antiqua, mediaevalis, orientalis, and microtus[11. There are two microtus-related plague...Yersinia pestis is the causative agent of bubonic and pneumonic plagues. Strains of Y. pestis are classified into four biovars： antiqua, mediaevalis, orientalis, and microtus[11. There are two microtus-related plague loci in China： the Microtus brandti plague focus in the Xilin Gol Grassland （focus L） and the Microtus fuscus plague focus in the Ojnghai-Tibet Plateau （focus M）.展开更多
Understanding the mechanisms of hard–soft material interaction under impact loading is important not only in the defense industry but also in daily life.However,traditional mesh-based spatial discretization methods t...Understanding the mechanisms of hard–soft material interaction under impact loading is important not only in the defense industry but also in daily life.However,traditional mesh-based spatial discretization methods that are time consuming owing to the need for frequent re-meshing,such as the finite element method and finite difference method,can hardly handle large deformation involving failure evolution in a multi-phase interaction environment.The objective of this research is to develop a quasi-meshless particle method based on the material point method for the model-based simulation of the hard–soft material interaction response.To demonstrate the proposed procedure,scenarios of a hard–soft material impact test are considered,where a force is applied to layers of materials and a hard bar with an initial velocity impacts a target with layers of different materials.The stress wave propagation and resulting failure evolution are simulated and compared with available data.Future research tasks are then discussed on the basis of the preliminary results.展开更多
基金supported by a grant from the National High Technology Research and Development Program of China (863 Program) (No. 2006AA2Z4A7)a grant from the National Key Program for Infectious Diseases of China (No.2008ZX1004-002)a grant from China Mega-Project for Infectious Disease (No.2011ZX10004-001)
文摘Objective To investigate genomic variations of two Chinese Yersinia pestis isolates that were isolated from different plague foci obtained from vaccine strain EV76 from the Yunnan province of China. Methods A microarray containing 12 000 probes covering the entire genome of seven Yersinie pestis and two Yersinia pseudotuberculosis strains, was used. PCR assays were performed to confirm microarray results. Results The gene variations detected included the absence of five genes related to the synthesis of betaine in both EV76 and another sequenced attenuated strain, KIM D27. Several genes related to phage-related membrane proteins were found to be absent in the Antiqua biovar Yunnan strain, 485, which was isolated from a rodent plague foci. Conclusion These findings provide initial insight into the distinct strains isolated from natural foci, within their genomic context, including Yunnan Y. pestis strains. This information will be used therefore to establish subsequent comparisons of these sequences with published complete genomes of other strains.
基金supported by the Industry Research Special Foundation of China Ministry of Health(No.201202021)
文摘Yersinia pestis is the causative agent of bubonic and pneumonic plagues. Strains of Y. pestis are classified into four biovars： antiqua, mediaevalis, orientalis, and microtus[11. There are two microtus-related plague loci in China： the Microtus brandti plague focus in the Xilin Gol Grassland （focus L） and the Microtus fuscus plague focus in the Ojnghai-Tibet Plateau （focus M）.
基金The National Natural Science Foundation of China(Grant Nos.51476150,11102185 and 11232003)U.S.Defense Threat Reduction Agency(Grant No.HDTRA1-10-1-0022)+1 种基金International Joint Research Program of Shanxi Province,China(Grant No.2014081028)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi
文摘Understanding the mechanisms of hard–soft material interaction under impact loading is important not only in the defense industry but also in daily life.However,traditional mesh-based spatial discretization methods that are time consuming owing to the need for frequent re-meshing,such as the finite element method and finite difference method,can hardly handle large deformation involving failure evolution in a multi-phase interaction environment.The objective of this research is to develop a quasi-meshless particle method based on the material point method for the model-based simulation of the hard–soft material interaction response.To demonstrate the proposed procedure,scenarios of a hard–soft material impact test are considered,where a force is applied to layers of materials and a hard bar with an initial velocity impacts a target with layers of different materials.The stress wave propagation and resulting failure evolution are simulated and compared with available data.Future research tasks are then discussed on the basis of the preliminary results.
