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infections among diarrheal outpatients in Shanghai: a retrospective case study

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《医学前沿（英文）》 2018年 第12卷 第1期   页码 98-103 doi: 10.1007/s11684-018-0614-3

摘要：

Cyclospora cayetanensis is a foodborne and waterborne pathogen that causes endemic and epidemic human diarrhea worldwide. A few epidemiological studies regarding C. cayetanensis infections in China have been conducted. During 2013, a total of 291 stool specimens were collected from patients with diarrhea at a hospital in urban Shanghai. C. cayetanensis was not detected in any of the stool specimens by traditional microscopy, whereas five stool specimens (1.72%, 5/291) were positive by PCR. These positive cases confirmed by molecular technology were all in the adult group (mean age 27.8 years; 2.94%, 5/170) with watery diarrhea. Marked infection occurred in the rainy season of May and July. Sequence and phylogenetic analyses of the partial 18S rRNA genes of C. cayetanensis isolated showed intra-species diversity of this parasite. This study showed, for the first time, that C. cayetanensis is a pathogen in outpatients with diarrhea in Shanghai, albeit at a low level. However, the transmission dynamics of this parasite in these patients remain uncertain.

关键词： Cyclospora cayetanensis     outpatients with diarrhea     stool specimens     18S rRNA gene    

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Simultaneous detection and characterization of toxigenic：Clostridium difficile directly from clinical stoolspecimens

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《医学前沿（英文）》 2018年 第12卷 第2期   页码 196-205 doi: 10.1007/s11684-017-0560-5

摘要：

We employed a multiplex polymerase chain reaction (PCR) coupled with capillary electrophoresis (mPCR-CE) targeting six Clostridium difficile genes, including tpi, tcdA, tcdB, cdtA, cdtB, and a deletion in tcdC for simultaneous detection and characterization of toxigenic C. difficile directly from fecal specimens. The mPCR-CE had a limit of detection of 10 colony-forming units per reaction with no cross-reactions with other related bacterial genes. Clinical validation was performed on 354 consecutively collected stool specimens from patients with suspected C. difficile infection and 45 isolates. The results were compared with a reference standard combined with BD MAX Cdiff, real-time cell analysis assay (RTCA), and mPCR-CE. The toxigenic C. difficile species were detected in 36 isolates and 45 stool specimens by the mPCR-CE, which provided a positive rate of 20.3% (81/399). The mPCR-CE had a specificity of 97.2% and a sensitivity of 96.0%, which was higher than RTCA (x2 = 5.67, P = 0.017) but lower than BD MAX Cdiff (P = 0.245). Among the 45 strains, 44 (97.8%) were determined as non-ribotype 027 by the mPCR-CE, which was fully agreed with PCR ribotyping. Even though ribotypes 017 (n = 8, 17.8%), 001 (n = 6, 13.3%), and 012 (n = 7, 15.6%) were predominant in this region, ribotype 027 was an important genotype monitored routinely. The mPCR-CE provided an alternative diagnosis tool for the simultaneous detection of toxigenic C. difficile in stool and potentially differentiated between RT027 and non-RT027.

关键词： Clostridium difficile     multiplex PCR     capillary electrophoresis     detection     characterization    

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Analysis of stress and failure in rock specimens with closed and open flaws on the surface

《结构与土木工程前沿（英文）》 2021年 第15卷 第5期   页码 1222-1237 doi: 10.1007/s11709-021-0773-1

摘要： The influence of closed and open surface flaws on the stress distribution and failure in rock specimens is investigated. Heterogeneous finite element models are developed to simulate the compression tests on flawed rock specimens. The simulated specimens include those with closed flaws and those with open flaws on the surface. Systematic analyses are conducted to investigate the influences of the flaw inclination, friction coefficient and the confining stress on failure behavior. Numerical results show significant differences in the stress, displacement, and failure behavior of the closed and open flaws when they are subjected to pure compression; however, their behaviors under shear and tensile loads are similar. According to the results, when compression is the dominant mode of stress applied to the flaw surface, an open flaw may play a destressing role in the rock and relocate the stress concentration and failure zones. The presented results in this article suggest that failure at the rock surface may be managed in a favorable manner by fabricating open flaws on the rock surface. The insights gained from this research can be helpful in managing failure at the boundaries of rock structures.

关键词： surface flaw     heterogeneity     circular hole     numerical modeling     relative displacement    

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Positive stool culture could predict the clinical outcomes of haploidentical hematopoietic stem cell

Lijuan Hu, Qi Wang, Xiaohui Zhang, Lanping Xu, Yu Wang, Chenhua Yan, Huan Chen, Yuhong Chen, Kaiyan Liu, Hui Wang, Xiaojun Huang, Xiaodong Mo

《医学前沿（英文）》 2019年 第13卷 第4期   页码 492-503 doi: 10.1007/s11684-019-0681-0

摘要： We aimed to identify the effect of positive stool cultures (PSCs) on the clinical outcomes of patients undergoing haploidentical hematopoietic stem cell transplantation (haplo-HSCT) ( = 332). PSCs were observed in 61 patients (PSC group, 18.4%). Enterobacteriaceae in stool specimens was associated with a higher risk of bloodstream infection, and in stool specimens was related to a higher risk of platelet engraftment failure. The cumulative incidence of infection-related mortality 1 year after haplo-HSCT in the PSC group was higher than that of the patients who showed persistently negative stool cultures (NSC group; 19.2% vs. 8.9%, = 0.017). The probabilities of overall survival (71.4% vs. 83.8%, = 0.031) and disease-free survival (69.6% vs. 81.0%, = 0.048) 1 year after haplo-HSCT for the PSC group were significantly lower than those for the NSC group, particularly for patients who had in their stool specimens. In multivariate analysis, in stool specimens significantly increased the risk of mortality and was associated with poorer survival. Our results showed that PSC influenced the clinical outcomes after haplo-HSCT, particularly those who had in their stool specimens.

关键词： haploidentical     hematopoietic stem cell transplantation     stool culture     Candida    

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on the influence of contact surface constraint on mechanical properties of rock-concrete composite specimens

Baoyun ZHAO, Yang LIU, Dongyan LIU, Wei HUANG, Xiaoping WANG, Guibao YU, Shu LIU

《结构与土木工程前沿（英文）》 2020年 第14卷 第2期   页码 322-330 doi: 10.1007/s11709-019-0594-7

摘要： The contact form of rock-concrete has a crucial influence on the failure characteristics of the stability of rock-concrete engineering. To study the influence of contact surface on the mechanical properties of rock-concrete composite specimens under compressive loads, the two different contact forms of rock-concrete composite specimens are designed, the mechanical properties of these two different specimens are analyzed under triaxial compressive condition, and analysis comparison on the stress-strain curves and failure forms of the two specimens is carried out. The influence of contact surface constraint on the mechanical properties of rock-concrete composite specimens is obtained. Results show that the stress and strain of rock-concrete composite specimens with contact surface constraint are obviously higher than those without. Averagely, compared with composite specimens without the contact surface, the existence of contact surface constraint can increase the axial peak stress of composite specimens by 24% and the axial peak strain by 16%. According to the characteristics of the fracture surface, the theory of microcrack development is used to explain the contact surface constraint of rock-concrete composite specimens, which explains the difference of mechanical properties between the two rock-concrete composite specimens in the experiment. Research results cannot only enrich the research content of the mechanics of rock contact, but also can serve as a valuable reference for the understanding of the corresponding mechanics mechanism of other similar composite specimens.

关键词： rock-concrete     composite specimen     contact surface     mechanical properties     failure mechanism    

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Crack evolution of soft–hard composite layered rock-like specimens with two fissures under uniaxial compression

《结构与土木工程前沿（英文）》 2021年 第15卷 第6期   页码 1372-1389 doi: 10.1007/s11709-021-0772-2

摘要： Acoustic emission and digital image correlation were used to study the spatiotemporal evolution characteristics of crack extension of soft and hard composite laminated rock masses (SHCLRM) containing double fissures under uniaxial compression. The effects of different rock combination methods and prefabricated fissures with different orientations on mechanical properties and crack coalescence patterns were analyzed. The characteristics of the acoustic emission source location distribution, and frequency changes of the crack evolution process were also investigated. The test results show that the damage mode of SHCLRM is related to the combination mode of rock layers and the orientation of fractures. Hard layers predominantly produce tensile cracks; soft layers produce shear cracks. The first crack always sprouts at the tip or middle of prefabricated fractures in hard layers. The acoustic emission signal of SHCLRM with double fractures has clear stage characteristics, and the state of crack development can be inferred from this signal to provide early warning for rock fracture instability. This study can provide a reference for the assessment of the fracture development status between adjacent roadways in SHCLRM in underground mines, as well as in roadway layout and support.

关键词： soft−hard composite layered rock mass     double cracks     crack evolution     acoustic emission     digital image correlation    

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Initiation and propagation laws of the glass cracks in specimens subjected to normal loading under the

WAN Zhen-ping, LIU Ya-jun, TANG Yong, YE Bang-yan

《机械工程前沿（英文）》 2006年 第1卷 第2期   页码 194-198 doi: 10.1007/s11465-005-0011-x

摘要： With more and more applications of glass in advanced fields of science, the demand for glass machining precision has increased greatly. More and more attention is being paid to glass cutting because precise glass parts with various shapes can be obtained at high efficiency and low cost. To improve the machining precision of part surfaces and to facilitate tool design and cutting parameter selection, the initiation and propagation laws of glass cracks in specimens subjected to normal loading by symmetric wedges were investigated. Research results show that initiation and propagation laws are the same with interior symmetric wedge angles of 30o-120o, while the laws are different with interior symmetric wedge angles equal to or more than "e150o. The relationship between medial crack length and normal loading was also investigated when specimens were indented by symmetrical wedges with interior angles of 30o-120o.

关键词： different     30o-120o     relationship     initiation     cutting parameter    

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Numerical evaluation of group-pile foundation subjected to cyclic horizontal load

Youngji JIN, Xiaohua BAO, Yoshimitsu KONDO, Feng ZHANG,

《结构与土木工程前沿（英文）》 2010年 第4卷 第2期   页码 196-207 doi: 10.1007/s11709-010-0021-6

摘要： In this paper, three-dimensional (3D) finite element analyses of a real-scale group-pile foundation subjected to horizontal cyclic loading are conducted using a program named DBLEAVES. In the simulations, nonlinear behaviors of ground and piles are described by subloading model and the axial-force dependent model (AFD model) which considered the axial-force dependency in the nonlinear moment-curvature relations. In order to consider the influence of an effective stress path on the prediction of the group-pile foundation, the analyses are conducted within the framework of the soil-water coupling method with finite-difference and finite-element regime. The material parameters of soils are determined based on conventional triaxial drained compression tests on undisturbed and remolded specimens. The applicability of the proposed numerical method is encouraging, and therefore, it is quite confident to say that the method can be used to predict the mechanical behaviors of group-pile foundation to a satisfactory accuracy, particularly with the effective stress analysis.

关键词： group-pile foundation     real-scale cyclic loading test     three-dimensional finite element method (3D-FEM)     soil-water coupling analysis     undisturbed and remolded specimens    

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砼非标准三点弯曲梁试件双K断裂参数

吴智敏,徐世烺,丁一宁,卢喜经,刘佳毅,丁生根

《中国工程科学》 2001年 第3卷 第4期   页码 76-81

摘要：

采用跨高比为2.5的非标准三点弯曲梁试件，利用在试验中测得的最大荷载Pmax及对应的裂缝口张开位移CMODc，根据渐近线性叠加假设，求得了砼裂缝亚临界扩展量∆ac。在此基础上，采用虚拟裂缝模型计算了不同初始缝长、不同试件髙度的砼非标准三点弯曲梁试件的起裂断裂韧度KiniIC、失稳断裂韧度KunIC及临界裂 缝尖端张开位移CTODc。计算结果表明，砼KunIC：与试件高度及初始缝高比无关；而KiniIC在初始缝髙比a0/h = 0.3〜0.5内，也是一稳定的常数且与试件高度无关。这说明砼双K断裂参数可以作为砼的材料常数。

关键词： 砼     三点弯曲梁     断裂参数    

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标题 作者 时间 类型 操作

infections among diarrheal outpatients in Shanghai: a retrospective case study

null

期刊论文

Simultaneous detection and characterization of toxigenic：Clostridium difficile directly from clinical stoolspecimens

null

期刊论文

Analysis of stress and failure in rock specimens with closed and open flaws on the surface

期刊论文

Positive stool culture could predict the clinical outcomes of haploidentical hematopoietic stem cell

Lijuan Hu, Qi Wang, Xiaohui Zhang, Lanping Xu, Yu Wang, Chenhua Yan, Huan Chen, Yuhong Chen, Kaiyan Liu, Hui Wang, Xiaojun Huang, Xiaodong Mo

期刊论文

on the influence of contact surface constraint on mechanical properties of rock-concrete composite specimens

Baoyun ZHAO, Yang LIU, Dongyan LIU, Wei HUANG, Xiaoping WANG, Guibao YU, Shu LIU

期刊论文

Crack evolution of soft–hard composite layered rock-like specimens with two fissures under uniaxial compression

期刊论文

Initiation and propagation laws of the glass cracks in specimens subjected to normal loading under the

WAN Zhen-ping, LIU Ya-jun, TANG Yong, YE Bang-yan

期刊论文

Numerical evaluation of group-pile foundation subjected to cyclic horizontal load

Youngji JIN, Xiaohua BAO, Yoshimitsu KONDO, Feng ZHANG,

期刊论文

砼非标准三点弯曲梁试件双K断裂参数

吴智敏,徐世烺,丁一宁,卢喜经,刘佳毅,丁生根

期刊论文