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.

Fabrication and characterization of fluorohydroxyapatite nanocrystals/poly(d,l-lactide) composite scaffolds

L. Cheng,S.M. Zhang,P.P. Chen,S.L. Huang,L. Liu,W. Zhou,J. Liu,H. Gong,Q.M. Luo 한국물리학회 2007 Current Applied Physics Vol.7 No.s1

Poly(D,L-lactide) (PDLLA)/uorohydroxyapatite nanocrystals (nano-F-HA) porous scaolds were successfully fabricated through asolvent-casting and particulate-leaching technique. Nano-HA/PDLLA scaold and PDLLA scaold were prepared by using the sameprocess for comparison. The structure, phase and morphology of the nanocomposite scaolds were observed by SEM. The results indi-cated that F-HA nanocrystals were homogeneously dispersed in the PDLLA matrix. The porosity of the scaolds was up to 90%, andmacropores and micropores coexisted and interconnected throughout the scaolds. Cell culture experiments demonstrated that the nano-F-HA/PDLLA scaffold had the best adhesion tendency to chondrocytes among the scaffolds investigated.

A two-photon fluorescent probe for specific detection of hydrogen sulfide based on a familiar ESIPT fluorophore bearing AIE characteristics

Chen, L.,Wu, D.,Lim, C.,Kim, D.,Nam, S. J.,Lee, W.,Kim, G.,Kim, H.,Yoon, J. unknown 2017 Chemical communications Vol. No.

<P>Hydrogen sulfide (H2S) is a signaling gasotransmitter, which plays various roles in modulating the functions of different systems. In this study, a 'turn-on'' fluorescent probe for H2S was developed. The probe, whose design is based on a familiar excited state intramolecular proton transfer (ESIPT) fluorophore bearing aggregation-induced emission (AIE) characteristics, was found to exhibit an 80-fold fluorescence enhancement along with a large Stokes shift upon the addition of H2S. Furthermore, the probe was successfully utilized to detect H2S in HeLa cells with both one-photon and two-photon microscopy.</P>

Characterization and Formation Mechanism of Ni3Si–Al2O3 Nanocomposite Prepared by Mechanochemical Reduction Method

H. Chen,D. M. Zhou,L. Cai,Y. Y. Wang,K. Yu 대한금속·재료학회 2020 METALS AND MATERIALS International Vol.26 No.2

In this present work, Ni3Si–Al2O3 nanocomposite powders were synthesized by mechanical milling using NiO, Si and Alas raw materials. The phase transformation, formation mechanism and microstructure evolution of the powders duringmechanical milling were investigated by X-ray difraction (XRD), diferential thermal analysis (DTA), scanning electronmicroscopy (SEM), transition electron microscopy (TEM) and microhardness measurements. Results showed that the Ni3Si,Al2O3 and Ni31Si12 phases formed after 5 h of milling with a rapid mechanically induced self-propagating synthesis mode. The average grain size and internal strain of Ni3Si and Al2O3 after 30 h of milling were (16.8 nm, 1.27%) and (19.6 nm,0.94%), respectively. The maximum microhardness value of 813 HV was obtained in the 30 h milled powder. The relationship between the hardness and grain size of the powders satisfes the Hall–Petch relationship. Ni3Si–Al2O3 nanocompositepowders are very stable during heating at 950 °C. By annealing of the milled powders leads to grain growth, internal strainand microhardness of Ni3Si powder decrease and transformation of disordered structure to an ordered state. A long-rangeordering parameter (LRO) of 0.97 for the ordered Ni3Si can be achieved after annealing at 950 °C for 2 h.

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>

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.

Sparse feature selection identifies H2A.Z as a novel, pattern-specific biomarker for asymmetrically self-renewing distributed stem cells

Huh, Y.H.,Noh, M.,Burden, F.R.,Chen, J.C.,Winkler, D.A.,Sherley, J.L. Elsevier 2015 Stem cell research Vol.14 No.2

There is a long-standing unmet clinical need for biomarkers with high specificity for distributed stem cells (DSCs) in tissues, or for use in diagnostic and therapeutic cell preparations (e.g., bone marrow). Although DSCs are essential for tissue maintenance and repair, accurate determination of their numbers for medical applications has been problematic. Previous searches for biomarkers expressed specifically in DSCs were hampered by difficulty obtaining pure DSCs and by the challenges in mining complex molecular expression data. To identify such useful and specific DSC biomarkers, we combined a novel sparse feature selection method with combinatorial molecular expression data focused on asymmetric self-renewal, a conspicuous property of DSCs. The analysis identified reduced expression of the histone H2A variant H2A.Z as a superior molecular discriminator for DSC asymmetric self-renewal. Subsequent molecular expression studies showed H2A.Z to be a novel ''pattern-specific biomarker'' for asymmetrically self-renewing cells, with sufficient specificity to count asymmetrically self-renewing DSCs in vitro and potentially in situ.

Analysis of the Inhibition Layer of Galvanized Dual-Phase Steels

( K K Wang ),( H P Wang ),( L Chang ),( D Can ),( T R Chen ),( H B Chen ) 한국부식방식학회(구 한국부식학회) 2012 Corrosion Science and Technology Vol.11 No.1

The formation of the Fe-Al inhibition layer in hot-dip galvanizing is a confusing issue for a long time. This study presents a characterization result on the inhibition layer fomed on C-Mn-Cr and C-Mn-Si dual-phase steels after a short time galvanizing. The samples were annealed at 800˚C for 60 s in N2-l0% H2 atmosphere with a dew point of -30˚C, and were then galvanized in a bath containing 0.2%Al. X-ray photoelectron spectroscopy (XPS) and transmission electron microscopy (TEM) was employed for characterization. The TEM electron diffraction shows that only Fe2Als intermetallic phase was formed. No orientation relationship between the Fe2Al5 phase and the steel substrate could be identified. Two peaks of Al 2p photoelectrons, one from metallic aluminum and the other from Al3+ ions, were detected in the inhibition layer, indicating that the layer is in fact a mixture of Fe2Al5 and A12O3. TEM/EDS analysis verifies the existence of A12O3 in the boundaries of Fe2Al5 grains. The nucleation of FeAl5 and the reduction of the surface oxide probably proceeded concurrently on galvanizing, and the residual oxides prohibited the heteroepitaxial growth of Fe2Al5.

Multiple model approach to evaluation of accelerated carbonation for steelmaking slag in a slurry reactor

Pan, S.Y.,Liu, H.L.,Chang, E.E.,Kim, H.,Chen, Y.H.,Chiang, P.C. Pergamon Press 2016 CHEMOSPHERE - Vol.154 No.-

Basic oxygen furnace slag (BOFS) exhibits highly alkaline properties due to its high calcium content, which is beneficial to carbonation reaction. In this study, accelerated carbonation of BOFS was evaluated under different reaction times, temperatures, and liquid-to-solid (L/S) ratios in a slurry reactor. CO<SUB>2</SUB> mass balance within the slurry reactor was carried out to validate the technical feasibility of fixing gaseous CO<SUB>2</SUB> into solid precipitates. After that, a multiple model approach, i.e., theoretical kinetics and empirical surface model, for carbonation reaction was presented to determine the maximal carbonation conversion of BOFS in a slurry reactor. On one hand, the reaction kinetics of BOFS carbonation was evaluated by the shrinking core model (SCM). Calcite (CaCO<SUB>3</SUB>) was identified as a reaction product through the scanning electronic microscopy and X-ray diffraction analyses, which provided the rationale of applying the SCM in this study. The rate-limiting step of carbonation was found to be ash-diffusion controlled, and the effective diffusivity for carbonation of BOFS in a slurry reactor were determined accordingly. On the other hand, the carbonation conversion of BOFS was predicted by the response surface methodology (RSM) via a nonlinear mathematical programming. According to the experimental data, the highest carbonation conversion of BOFS achieved was 57% under an L/S ratio of 20 mL g<SUP>-1</SUP>, a CO<SUB>2</SUB> flow rate of 0.1 L min<SUP>-1</SUP>, and a pressure of 101.3 kPa at 50 <SUP>o</SUP>C for 120 min. Furthermore, the applications and limitations of SCM and RSM were examined and exemplified by the carbonation of steelmaking slags.

The Expression of Genes Related to Egg Production in the Liver of Taiwan Country Chickens

Ding, S.T.,Ko, Y.H.,Ou, B.R.,Wang, P.H.,Chen, C.L.,Huang, M.C.,Lee, Y.P.,Lin, E.C.,Chen, C.F.,Lin, H.W.,Cheng, Winston Teng Kuei Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.1

The purpose of this study was to detect expression of genes related to egg production in Taiwan Country chickens by suppression subtractive hybridization. Liver samples of mRNA extraction from two Taiwan Country chicken strains (L2 and B), originated from the same population but with very distinct egg production rates after long-term selection for egg and meat production respectively. Two-way subtraction was performed. The hepatic cDNA from the low egg production chickens (B) was subtracted from the hepatic cDNA from the high egg production strain (L2). The reversed subtraction (L2 from B) was also performed. The resulting differentially expressed gene fragments were cloned and sequenced. We sequenced 288 clones from the forward subtraction and 96 clones from the reverse subtraction. These genes were subjected to further screening to confirm the differential expression between the two genetic breeds of chickens. The apolipoprotein B (apoB) was expressed to a greater extent in the liver of the L2 than in the B line chickens. The 5-aminoimidazole- 4-carboxamide ribonucleotide formyltransferase/IMP cyclohydrolase (PURH) was expressed to a greater extent in the liver of the B than in the L2 strain chickens. We demonstrated that both apoB and PURH were more highly expressed in the liver than that in other tissues (muscle, ovary, and oviduct) in laying Taiwan Country chickens. Taken together, these data suggest that after the selection for egg production, expression of apoB and PURH genes were also changed. Whether the changed expression of these genes is directly related to egg production is not known, but these two genes may be useful markers for egg laying performance in Taiwan Country chickens.