Multilocus Sequence Typing and Virulence Factors Analysis of Escherichia coli O157 Strains in China

Xiao W. Ji,Ya L. Liao,Ye F. Zhu,Hai G. Wang,Ling Gu,Jiang Gu,Chen Dong,Hong L. Ding,Xu H. Mao,Feng C. Zhu,Quan M. Zou 한국미생물학회 2010 The journal of microbiology Vol.48 No.6

Escherichia coli O157:H7, an important food-borne pathogen, has become a major public health concern worldwide. The aim of this study was to investigate the molecular epidemiologic feature of E. coli O157:H7strains in China. 105 E. coli O157:H7 isolates were collected from various hosts and places over 9 years. A multilocus sequence typing scheme (MLST) was applied for bacteria genotyping and polymerase chain reaction (PCR) was used for virulence factor identification. Seven new MLST sequence types (STs), namely ST836, ST837, ST838, ST839, ST840, ST841, and ST842 were identified, which grouped into two lineages. Phylogenetic analysis suggested that the most two frequent STs in China, ST837 and ST836, may be the derivatives of E. coli O157:H7 Sakai or E. coli O157:H7 EDL933. Geographical diversity and host variety of E. coli O157:H7 were observed in China. In addition, the different distribution of tccp was detected. The data presented herein provide new insights into the molecular epidemiologic feature of E. coli O157:H7, and aid in the investigation of the transmission regularity and evolutionary mechanism of E. coli O157:H7.

China Spallation Neutron Source: Accelerator Design Iterations and R&D Status

J. Wei,C.-D. Deng,C.-H. Wang,C.-T. Shi,H. Sun,H.-F. Ouyang,H.-M. Qu,H.-Y. Dong,J. Li,J. Zhang,J.-S. Cao,J.-Y. Tang,L. Dong,L.-L. Wang,Q. Qin,Q.-B. Wang,S. Wang,S.-N. Fu,S.-X Fang,T. -G. Xu,W. Kang,Y.- 한국물리학회 2007 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.50 No.I

The China Spallation Neutron Source (CSNS) is a high-power, accelerator-based project currently under preparation. The accelerator complex consists of an H$^-$ ion source, an H$^-$ linac, a rapid-cycling proton synchrotron, and the transport lines. During the past year, the design of most accelerator systems went through major iterations, and initial research and developments was started on the prototyping of several key components.

The Kinetics of Anodic Dissolution and Repassivation on 316L Stainless Steel in Borate Buffer Solution Studied by Abrading Electrode Technique

( H S Xu1 ),( D B Sun ),( H Y Yu ),( H M Meng ) 한국부식방식학회 2015 Corrosion Science and Technology Vol.14 No.6

The capacity of passive metal to repassivate after film damage determines the development of local corrosion and the resistance to corrosion failures. In this work, the repassivation kinetics of 316L stainless steel (316LSS) was investigated in borate buffer solution (pH 9. 1) using a novel abrading electrode technique. The repassivation kinetics was analyzed in terms of the current density flowing from freshly bare 316L SS surface as measured by a potentiostatic method. During the early phase of decay (t < 2 s), according to the Avrami kinetics-based film growth model, the transient current was separated into anodic dissolution (idiss) and film formation (ifilm) components and analyzed individually. The film reformation rate and thickness were compared according to applied potential. Anodic dissolution initially dominated the repassivation for a short time, and the amount of dissolution increased with increasing applied potential in the passive region. Film growth at higher potentials occurred more rapidly compared to at lower potentials. Increasing the applied potential from 0 VSCE to 0. 8 VSCE resulted in a thicker passive film (0. 12 to 0. 52 nm). If the oxide monolayer covered the entire bare surface (θ=1), the electric field strength through the thin passive film reached 1. 6 × 107 V/cm.

여대생의 인유두종 바이러스 및 인유두종 바이러스 백신 관련 지식과 예방접종 실태와의 상관관계

Xu, Meiling,김현지,이희수,이윤지,한동연,박소영,엄효윤,최정민,홍서진,홍예림,이경은,이혜림 이화여자대학교 간호과학대학 2017 이화간호학회지 Vol.- No.51

Purpose: Human Papillomavirus (HPV) vaccination is readily available, but immunization rate is minimal. Lack of knowledge concerning the HPV infection and vaccine is expected as the primary reason. The correlation between knowledge levels and vaccination will provide applicable guidelines for successful interventions. Method: 309 female university students have completed surveys September 2016, reporting of HPV infection knowledge, HPV vaccine knowledge, source of knowledge, and attitudes concerning vaccination. Result: HPV infection and vaccine knowledge levels were both suboptimal(9.57±1.84, 7.59±1.58), and the Internet(16.2%) was recognized as the most generally used means of obtaining information on the HPV vaccine. However, vaccination rates were reported to be low(28.2%), with lack of information(46.6%) hindering immunization. Correlations were found between HPV infection knowledge and cervical cancer insight, but the correlations between knowledge levels and vaccination rates were insignificant. Conclusion: Prior information on cervical cancer had an effect on the knowledge levels of HPV infection, but other factors were insignificant. Lack of information on the HPV vaccine was speculated, thus programs should focus on accessibility and effectiveness.

Pseudonocardia endophytica sp. nov., isolated from the pharmaceutical plant Lobelia clavata

Chen, H.-H.,Qin, S.,Li, J.,Zhang, Y.-Q.,Xu, L.-H.,Jiang, C.-L.,Kim, C.-J.,Li, W.-J. Microbiology Society 2009 International journal of systematic and evolutiona Vol.59 No.3

<P>An endophytic actinomycete strain, designated YIM 56035(T), was isolated from the inner tissue of the traditional Chinese medicinal plant Lobelia clavata. The strain stained Gram-positive, was aerobic and exhibited branching, white aerial mycelium and yellowish-brown substrate mycelium. The strain formed spore chains on aerial hyphae. The G+C content of the genomic DNA was 70.3 mol%. On the basis of morphological, physiological, chemotaxonomic and phylogenetic characteristics, strain YIM 56035(T) was assigned to the genus Pseudonocardia. Analysis of 16S rRNA gene sequences showed 98.5, 97.3, 97.3 and 97.1 % similarity to the closely related type strains Pseudonocardia kongjuensis LM 157(T), Pseudonocardia autotrophica IMSNU 20050(T), Pseudonocardia ammonioxydans H9(T) and Pseudonocardia compacta IMSNU 20111(T), respectively. The results of DNA-DNA hybridizations and comparison of some phenotypic characteristics revealed that the strain represents a novel species of the genus Pseudonocardia. The name Pseudonocardia endophytica sp. nov. is proposed, with the type strain YIM 56035(T) (=DSM 44969(T) =CCTCC AA 206026(T) =KCTC 19150(T)).</P>

Structural dependence of the piezoelectric properties of KNbO₃ nanowires synthesized by the hydrothermal method

Joung, M.R.,Seo, I.T.,Kim, J.S.,Xu, H.,Han, G.,Kang, M.G.,Kang, C.Y.,Yoon, S.J.,Nahm, S. Elsevier Science 2013 ACTA MATERIALIA Vol.61 No.10

Because of the presence of OH<SUP>-</SUP> and H<SUB>2</SUB>O in the KN unit cell, tetragonal KNbO<SUB>3</SUB> (KN) nanowires were formed when the synthesis was carried out at 120<SUP>o</SUP>C for 48h. However, when the fabrication was conducted at high temperatures (≥150<SUP>o</SUP>C) or at 120<SUP>o</SUP>C for a long period of time (≥72h), orthorhombic KN nanowires were formed. Moreover, the KN nanowires synthesized at 120<SUP>o</SUP>C for 60h showed a morphotropic phase boundary (MPB) structure in which both tetragonal and orthorhombic structures coexisted. Tetragonal, orthorhombic and MPB KN nanowires were also grown on the Nb<SUP>5+</SUP>-doped SrTiO<SUB>3</SUB> substrate, and their d<SUB>33</SUB> values were measured for the first time. A tetragonal KN nanowire exhibited a d<SUB>33</SUB> value of 23.5pmV<SUP>-1</SUP>, which is larger than that of the orthorhombic KN nanowire (11.6pmV<SUP>-1</SUP>), probably because of the softening effect of the metal vacancies. The MPB KN nanowires exhibited a larger d<SUB>33</SUB> value of 40.0pmV<SUP>-1</SUP>. The d<SUB>33</SUB> values of KN nanowires increased to 104.5, 137.1 and 146.0pmV<SUP>-1</SUP> for the orthorhombic, tetragonal and MPB KN nanowires, respectively, after the KN nanowires were poled along the [100] direction by application of a DC voltage of 10V.

The Thermal Stability and Elevated Temperature Mechanical Properties of Spray-Deposited $SiC_P$/Al-11.7Fe-1.3V-1.7Si Composite

Hao, L.,He, Y.Q.,Wang, Na,Chen, Z.H.,Chen, Z.G.,Yan, H.G.,Xu, Z.K. The Korean Society for Composite Materials 2009 Advanced composite materials Vol.18 No.4

The thermal stability and elevated temperature mechanical properties of $SiC_P$/Al-11.7Fe-1.3V-1.7Si (Al-11.7Fe-1.3V-1.7Si reinforced with SiC particulates) composites sheets prepared by spray deposition (SD) $\rightarrow$ hot pressing $\rightarrow$ rolling process were investigated. The experimental results showed that the composite possessed high ${\sigma}_b$ (elevated temperature tensile strength), for instance, ${\sigma}_b$ was 315.8 MPa, which was tested at $315^{\circ}C$, meanwhile the figure was 232.6 MPa tested at $400^{\circ}C$, and the elongations were 2.5% and 1.4%, respectively. Furthermore, the composite sheets exhibited excellent thermal stability: the hardness showed no significant decline after annealing at $550^{\circ}C$ for 200 h or at $600^{\circ}C$ for 10 h. The good elevated temperature mechanical properties and excellent thermal stability should mainly be attributed to the formation of spherical ${\alpha}-Al_{12}(Fe,\;V)_3Si$ dispersed phase particulates in the aluminum matrix. Furthermore, the addition of SiC particles into the alloy is another important factor, which the following properties are responsible for. The resultant Si of the reaction between Al matrix and SiC particles diffused into Al matrix can stabilize ${\alpha}-Al_{12}(Fe,\;V)_3Si$ dispersed phase; in addition, the interface (Si layer) improved the wettability of Al/$SiC_P$, hence, elevated the bonding between them. Furthermore, the fine $Al_4C_3$ phase also strengthened the matrix as a dispersion-strengthened phase. Meanwhile, load is transferred from Al matrix to SiC particles, which increased the cooling rate of the melt droplets and improved the solution strengthening and dispersion strengthening.

Separation dynamics of hydrogen isotope gas in mesoporous and microporous adsorbent beds at 77 K: SBA-15 and zeolites 5A, Y, 10X

Chu, X.Z.,Cheng, Z.P.,Xiang, X.X.,Xu, J.M.,Zhao, Y.J.,Zhang, W.G.,Lv, J.S.,Zhou, Y.P.,Zhou, L.,Moon, D.K.,Lee, C.H. Pergamon Press ; Elsevier Science Ltd 2014 International journal of hydrogen energy Vol.39 No.9

The separation of a hydrogen isotope mixture on porous materials was studied using equilibrium and breakthrough experiments. The adsorption equilibria of H<SUB>2</SUB> and D<SUB>2</SUB> on SBA-15 with mesopores and molecular sieves 5A, Y, and 10X with micropores were measured at 77 K using the volumetric method. The breakthrough experiments of a H<SUB>2</SUB> and D<SUB>2</SUB> mixture in each adsorbent bed were carried out at various conditions of flow rate and pressure. The equilibrium ratio of D<SUB>2</SUB> to H<SUB>2</SUB> on mesoporous molecular sieves was larger than the ratio on microporous molecular sieves (SBA-15 > 10X > Y > 5A), but the difference among the adsorbents decreased with increases in pressure. On the other hand, the order of breakthrough separation factor showed the opposite result (SBA-15 < 10X < Y < 5A). The breakthrough separation factors for zeolite 10X was approximately equal to the equilibrium ratio of D<SUB>2</SUB> to H<SUB>2</SUB> at the corresponding partial pressures, whereas zeolites 5A and Y showed higher breakthrough separation factors than their equilibrium ratios. In SBA-15, the separation factors from breakthrough results were even smaller than the corresponding equilibrium ratio. In the microporous adsorbent with a limited pore size (zeolite 5A in the study), the diffusion mechanism contributed to the separation of hydrogen isotope gases as one of key factors.

Evaluation of different pretreatments on organic matter solubilization and hydrogen fermentation of mixed microalgae consortia

Kumar, G.,Sivagurunathan, P.,Thi, N.B.D.,Zhen, G.,Kobayashi, T.,Kim, S.H.,Xu, K. Pergamon Press 2016 International journal of hydrogen energy Vol.41 No.46

<P>This study investigated the effects of pretreatment methods (such as autoclave, ultra-sonication and electrolysis) of mixed microalgae consortia (predominantly composed of Scenedesmus followed by Chlorella species) from natural ecological niche. In addition, the cultivated biomass (wet) was subsequently utilized for fermentative H-2 production in mesophilic regime. The results showed that peak hydrogen production rate (HPR) and hydrogen yield (HY) were achieved from electrolysis pretreated algal consortia as 236 +/- 14 mL/L-d and 37.7 +/- 0.4 mL/g (volatile solids) VSadded, whereas the untreated algal consortia resulted in the turnout as 64 +/- 5 mL/L-d and 9.5 +/- 0.0 mL/g VSadded, respectively. The significant increment observed in HPR and HY values were nearly 4 times higher. The solubilization of organic matter during the pretreatment showed positive correlation with the H-2 production. The energy generation rate and yield of the corresponding pretreatment methods were as follows, 1.44, 1.79 and 2.65 kJ/L-d for autoclave, ultra-sonication and electrolysis, the corresponding yields also fell in the range of 0.32, 0.41 and 0.43 kJ/g VSadded, respectively. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.</P>

Measurement of aerodynamic coefficients of tower components of Tsing Ma Bridge under yaw winds

Zhu, L.D.,Xu, Y.L.,Zhang, F.,Xiang, H.F. Techno-Press 2003 Wind and Structures, An International Journal (WAS Vol.6 No.1

Tsing Ma Bridge in Hong Kong is the longest suspension bridge in the world carrying both highway and railway. It has two H-shape concrete towers, each of which is composed of two reinforced concrete legs and four deep transverse prestressed concrete beams. A series of wind tunnel tests have been performed to measure the aerodynamic coefficients of the tower legs and transverse beams in various arrangements. A 1:100 scaled 3D rigid model of the full bridge tower assembled from various tower components has been constructed for different test cases. The aerodynamic coefficients of the lower and upper segments of the windward and leeward tower legs and those of the transverse beams at different levels, with and without the dummy bridge deck model, were measured as a function of yaw wind angle. The effects of wind interference among the tower components and the influence of the bridge deck on the tower aerodynamic coefficients were also investigated. The results achieved can be used as the pertinent data for the comparison of the computed and field-measured fully coupled buffeting responses of the entire bridge under yaw winds.