48 CFR 1552.209-74 - Limitation of future contracting.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Limitation of future contracting. 1552.209-74 Section 1552.209-74 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION... Future Contracting, Alternate IV (TES) (APR 2004) (a) The parties to this contract agree that the...

48 CFR 1552.209-74 - Limitation of future contracting.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Limitation of future contracting. 1552.209-74 Section 1552.209-74 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION... Future Contracting, Alternate IV (TES) (APR 2004) (a) The parties to this contract agree that the...

48 CFR 1552.235-76 - Treatment of Confidential Business Information (APR 1996).

Code of Federal Regulations, 2010 CFR

2010-10-01

... Business Information (APR 1996). 1552.235-76 Section 1552.235-76 Federal Acquisition Regulations System... Provisions and Clauses 1552.235-76 Treatment of Confidential Business Information (APR 1996). As prescribed in 1535.007-70(c), insert the following clause: Treatment of Confidential Business Information (TSCA...

48 CFR 1552.227-76 - Project employee confidentiality agreement.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Project employee confidentiality agreement. 1552.227-76 Section 1552.227-76 Federal Acquisition Regulations System ENVIRONMENTAL... electrical services, provisions which shall conform substantially to the language of this clause, including...

48 CFR 1552.209-71 - Organizational conflicts of interest.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Organizational conflicts of interest. 1552.209-71 Section 1552.209-71 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION... through simplified acquisition procedures, use of the clause is optional. Organizational Conflicts of...

48 CFR 1552.215-71 - Evaluation factors for award.

Code of Federal Regulations, 2014 CFR

2014-10-01

... award. 1552.215-71 Section 1552.215-71 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION... acceptable, equal price (cost) offers, the Government will consider socioeconomic, environmental and other similar factors, as listed below in descending order of importance: (b) Factors and significant subfactors...

48 CFR 1552.215-71 - Evaluation factors for award.

Code of Federal Regulations, 2012 CFR

2012-10-01

... award. 1552.215-71 Section 1552.215-71 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION... acceptable, equal price (cost) offers, the Government will consider socioeconomic, environmental and other similar factors, as listed below in descending order of importance: (b) Factors and significant subfactors...

48 CFR 1552.215-71 - Evaluation factors for award.

Code of Federal Regulations, 2011 CFR

2011-10-01

... award. 1552.215-71 Section 1552.215-71 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION... acceptable, equal price (cost) offers, the Government will consider socioeconomic, environmental and other similar factors, as listed below in descending order of importance: (b) Factors and significant subfactors...

48 CFR 1552.215-71 - Evaluation factors for award.

Code of Federal Regulations, 2013 CFR

2013-10-01

... award. 1552.215-71 Section 1552.215-71 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION... acceptable, equal price (cost) offers, the Government will consider socioeconomic, environmental and other similar factors, as listed below in descending order of importance: (b) Factors and significant subfactors...

48 CFR 1552.227-76 - Project employee confidentiality agreement.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Project employee confidentiality agreement. 1552.227-76 Section 1552.227-76 Federal Acquisition Regulations System ENVIRONMENTAL... electrical services, provisions which shall conform substantially to the language of this clause, including...

48 CFR 1552.227-76 - Project employee confidentiality agreement.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Project employee confidentiality agreement. 1552.227-76 Section 1552.227-76 Federal Acquisition Regulations System ENVIRONMENTAL... electrical services, provisions which shall conform substantially to the language of this clause, including...

48 CFR 1552.209-71 - Organizational conflicts of interest.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Organizational conflicts of interest. 1552.209-71 Section 1552.209-71 Federal Acquisition Regulations System ENVIRONMENTAL... accomplished through simplified acquisition procedures, use of the clause is optional. Organizational Conflicts...

48 CFR 1552.209-71 - Organizational conflicts of interest.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Organizational conflicts of interest. 1552.209-71 Section 1552.209-71 Federal Acquisition Regulations System ENVIRONMENTAL... accomplished through simplified acquisition procedures, use of the clause is optional. Organizational Conflicts...

48 CFR 1552.209-71 - Organizational conflicts of interest.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Organizational conflicts of interest. 1552.209-71 Section 1552.209-71 Federal Acquisition Regulations System ENVIRONMENTAL... accomplished through simplified acquisition procedures, use of the clause is optional. Organizational Conflicts...

48 CFR 1552.227-76 - Project employee confidentiality agreement.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Project employee confidentiality agreement. 1552.227-76 Section 1552.227-76 Federal Acquisition Regulations System ENVIRONMENTAL... electrical services, provisions which shall conform substantially to the language of this clause, including...

48 CFR 1552.242-72 - Financial administrative contracting officer.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) Negotiate advance agreements applicable to treatment of costs and to Independent Research & Development/Bid and Proposal costs. (3) Negotiate changes to interim billing rates and establish final indirect cost... contracting officer. 1552.242-72 Section 1552.242-72 Federal Acquisition Regulations System ENVIRONMENTAL...

48 CFR 1552.215-71 - Evaluation factors for award.

Code of Federal Regulations, 2010 CFR

2010-10-01

... for technical acceptability evaluation: (c) Factors for past performance evaluation (optional): (End... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Evaluation factors for award. 1552.215-71 Section 1552.215-71 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION...

The surface fatigue life of contour induction hardened AISI 1552 gears

NASA Astrophysics Data System (ADS)

Townsend, Dennis P.; Turza, Alan; Chaplin, Mike

1995-07-01

Two groups of spur gears manufactured from two different materials and heat treatments were endurance tested for surface fatigue life. One group was manufactured from AISI 1552 and was finished ground to a 0.4 micron (16 micro-in.) rms surface finish and then dual frequency contour induction hardened. The second group was manufactured from CEVM AISI 9310 and was carburized, hardened, and ground to a 0.4 micron (16 micro-in.) rms surface finish. The gear pitch diameter was 8.89 cm (3.5 in.). Test conditions were a maximum Hertz stress of 1.71 GPa (248 ksi), a bulk gear temperature of approximately 350 K (170 F) and a speed of 10,000 rpm. The lubricant used for the tests was a synthetic paraffinic oil with an additive package. The test results showed that the 10 percent surface fatigue (pitting) life of the contour hardened AISI 1552 test gears was 1.7 times that of the carburized and hardened AISI 9310 test gears. Also there were two early failures of the AISI 1552 gears by bending fatigue.

The Surface Fatigue Life of Contour Induction Hardened AISI 1552 Gears

NASA Technical Reports Server (NTRS)

Townsend, Dennis P.; Turza, Alan; Chaplin, Mike

1995-01-01

Two groups of spur gears manufactured from two different materials and heat treatments were endurance tested for surface fatigue life. One group was manufactured from AISI 1552 and was finished ground to a 0.4 micron (16 micro-in.) rms surface finish and then dual frequency contour induction hardened. The second group was manufactured from CEVM AISI 9310 and was carburized, hardened, and ground to a 0.4 micron (16 micro-in.) rms surface finish. The gear pitch diameter was 8.89 cm (3.5 in.). Test conditions were a maximum Hertz stress of 1.71 GPa (248 ksi), a bulk gear temperature of approximately 350 K (170 F) and a speed of 10,000 rpm. The lubricant used for the tests was a synthetic paraffinic oil with an additive package. The test results showed that the 10 percent surface fatigue (pitting) life of the contour hardened AISI 1552 test gears was 1.7 times that of the carburized and hardened AISI 9310 test gears. Also there were two early failures of the AISI 1552 gears by bending fatigue.

49 CFR 1552.5 - Fees.

Code of Federal Regulations, 2014 CFR

2014-10-01

... HOMELAND SECURITY CIVIL AVIATION SECURITY FLIGHT SCHOOLS Flight Training for Aliens and Other Designated... information required under § 1552.3 to TSA. (2) TSA will not issue any fee refunds, unless a fee was paid in...

49 CFR 1552.5 - Fees.

Code of Federal Regulations, 2011 CFR

2011-10-01

... HOMELAND SECURITY CIVIL AVIATION SECURITY FLIGHT SCHOOLS Flight Training for Aliens and Other Designated... information required under § 1552.3 to TSA. (2) TSA will not issue any fee refunds, unless a fee was paid in...

48 CFR 1552.203-71 - Display of EPA Office of Inspector General Hotline poster.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Inspector General Hotline poster. 1552.203-71 Section 1552.203-71 Federal Acquisition Regulations System... Provisions and Clauses 1552.203-71 Display of EPA Office of Inspector General Hotline poster. As prescribed... all contract options. Display of EPA Office of Inspector General Hotline Poster (AUG 2000) (a) For EPA...

48 CFR 1552.203-71 - Display of EPA Office of Inspector General Hotline poster.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Inspector General Hotline poster. 1552.203-71 Section 1552.203-71 Federal Acquisition Regulations System... Provisions and Clauses 1552.203-71 Display of EPA Office of Inspector General Hotline poster. As prescribed... all contract options. Display of EPA Office of Inspector General Hotline Poster (AUG 2000) (a) For EPA...

48 CFR 1552.203-71 - Display of EPA Office of Inspector General Hotline poster.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Inspector General Hotline poster. 1552.203-71 Section 1552.203-71 Federal Acquisition Regulations System... Provisions and Clauses 1552.203-71 Display of EPA Office of Inspector General Hotline poster. As prescribed... all contract options. Display of EPA Office of Inspector General Hotline Poster (AUG 2000) (a) For EPA...

48 CFR 1552.203-71 - Display of EPA Office of Inspector General Hotline poster.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Inspector General Hotline poster. 1552.203-71 Section 1552.203-71 Federal Acquisition Regulations System... Provisions and Clauses 1552.203-71 Display of EPA Office of Inspector General Hotline poster. As prescribed... all contract options. Display of EPA Office of Inspector General Hotline Poster (AUG 2000) (a) For EPA...

48 CFR 1552.203-71 - Display of EPA Office of Inspector General Hotline poster.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Inspector General Hotline poster. 1552.203-71 Section 1552.203-71 Federal Acquisition Regulations System... Provisions and Clauses 1552.203-71 Display of EPA Office of Inspector General Hotline poster. As prescribed... all contract options. Display of EPA Office of Inspector General Hotline Poster (AUG 2000) (a) For EPA...

48 CFR 1552.209-76 - Contractor performance evaluations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Contractor performance... 1552.209-76 Contractor performance evaluations. As prescribed in section 1509.170-1, insert the following clause in all applicable solicitations and contracts. Contractor Performance Evaluations (OCT 2002...

48 CFR 1552.223-71 - EPA Green Meetings and Conferences.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true EPA Green Meetings and Conferences. 1552.223-71 Section 1552.223-71 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION... provision or language substantially the same as the provision in solicitations for meetings and conference...

48 CFR 1552.217-74 - Option for increased quantity-cost-plus-award-fee contract.

Code of Federal Regulations, 2010 CFR

2010-10-01

... quantity-cost-plus-award-fee contract. 1552.217-74 Section 1552.217-74 Federal Acquisition Regulations... Texts of Provisions and Clauses 1552.217-74 Option for increased quantity—cost-plus-award-fee contract. As prescribed in 1517.208(e), insert this contract clause in cost-plus-award-fee term contracts when...

Genetic and antigenic relationship of foot-and-mouth disease virus serotype O isolates with the vaccine strain O1/BFS.

PubMed

Xu, Wanhong; Zhang, Zhidong; Nfon, Charles; Yang, Ming

2018-05-15

Foot-and-mouth disease serotype O viruses (FMDV/O) are responsible for the most outbreaks in FMD endemic countries. O1/BFS is one of the recommended FMD/O vaccine strains by World Reference Laboratory for FMD. In the current study, FMDV/O1 BFS vaccine strain and serotype O field isolates (45) were analyzed phylogenetically and antigenically to gain more insight into the genetic and antigenic characteristics of the vaccine strain and field isolates. O1/BFS showed similarity with 89% of the field isolates using a virus neutralization test (VNT). The P1 region encoding the FMDV capsid was sequenced and analysed for 46 strains of FMDV/O. Phylogenetic analysis showed these viruses originated from five continents and covered eight of 11 reported topotypes. Five isolates that demonstrated low antigenic similarities with O1/BFS were analyzed for their antigenic variation at the known neutralizing antigenic sites. Three of the five isolates demonstrated unique amino acid substitutions at various antigenic sites. No unique amino acid substitutions were observed for the other two unmatched isolates. Positively selected residues were identified on the surface of the FMD virus capsid supporting that it is important to continuously monitor field isolates for their antigenic and phenotypic changes. In conclusion, the vaccine strain O1/BFS is likely to confer protection against 89% of the 45 FMDV/O isolates based on VNT. Thus O1/BFS vaccine strain is still suitable for use in global FMD serotype O outbreak control. Combining data from phylogenetic, molecular and antigenic analysis can provide improvements in the process of vaccine selection. Crown Copyright © 2018. Published by Elsevier Ltd. All rights reserved.

48 CFR 1552.209-70 - Organizational conflict of interest notification.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Clauses 1552.209-70 Organizational conflict of interest notification. As prescribed in 1509.507-1(b) insert the following solicitation provision in all solicitations. Organizational Conflict of Interest... subcontractor) may have a potential organizational conflict of interest. (b) Prospective Contractors should...

Strain driven sequential magnetic transitions in strained GdTiO3 on compressive substrates: a first-principles study.

PubMed

Yang, Li-Juan; Weng, Ya-Kui; Zhang, Hui-Min; Dong, Shuai

2014-11-26

The compressive strain effect on the magnetic ground state and electronic structure of strained GdTiO3 has been studied using the first-principles method. Unlike the cases of congeneric YTiO3 and LaTiO3, both of which become the A-type antiferromagnetism on the (0 0 1) LaAlO3 substrate despite their contrastive magnetism, the ground state of strained GdTiO3 on the LaAlO3 substrate changes from the original ferromagnetism to a G-type antiferromagnetim, instead of the A-type one although Gd(3+) is between Y(3+) and La(3+). It is only when the in-plane compressive strain is large enough, e.g. on the (0 0 1) YAlO3 substrate, that the ground state finally becomes the A-type. The band structure calculation shows that the compressive strained GdTiO3 remains insulating, although the band gap changes a little in the strained GdTiO3.

48 CFR 1552.211-79 - Compliance with EPA Policies for Information Resources Management.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Policies for Information Resources Management. 1552.211-79 Section 1552.211-79 Federal Acquisition... Information Resources Management (OCT 2000) (a) Definition. Information Resources Management (IRM) is defined... includes both information itself, and the management of information and related resources such as personnel...

Strain driven sequential magnetic transitions in strained GdTiO3 on compressive substrates: a first-principles study

NASA Astrophysics Data System (ADS)

Yang, Li-Juan; Weng, Ya-Kui; Zhang, Hui-Min; Dong, Shuai

2014-11-01

The compressive strain effect on the magnetic ground state and electronic structure of strained GdTiO3 has been studied using the first-principles method. Unlike the cases of congeneric YTiO3 and LaTiO3, both of which become the A-type antiferromagnetism on the (0 0 1) LaAlO3 substrate despite their contrastive magnetism, the ground state of strained GdTiO3 on the LaAlO3 substrate changes from the original ferromagnetism to a G-type antiferromagnetim, instead of the A-type one although Gd3+ is between Y3+ and La3+. It is only when the in-plane compressive strain is large enough, e.g. on the (0 0 1) YAlO3 substrate, that the ground state finally becomes the A-type. The band structure calculation shows that the compressive strained GdTiO3 remains insulating, although the band gap changes a little in the strained GdTiO3.

Efficient Vpu-Mediated Tetherin Antagonism by an HIV-1 Group O Strain

PubMed Central

Mack, Katharina; Starz, Kathrin; Sauter, Daniel; Langer, Simon; Bibollet-Ruche, Frederic; Learn, Gerald H.; Stürzel, Christina M.; Leoz, Marie; Plantier, Jean-Christophe; Geyer, Matthias; Hahn, Beatrice H.

2017-01-01

ABSTRACT Simian immunodeficiency viruses (SIVs) use their Nef proteins to counteract the restriction factor tetherin. However, a deletion in human tetherin prevents antagonism by the Nef proteins of SIVcpz and SIVgor, which represent the ape precursors of human immunodeficiency virus type 1 (HIV-1). To promote virus release from infected cells, pandemic HIV-1 group M strains evolved Vpu as a tetherin antagonist, while the Nef protein of less widespread HIV-1 group O strains acquired the ability to target a region adjacent to this deletion. In this study, we identified an unusual HIV-1 group O strain (RBF206) that evolved Vpu as an effective antagonist of human tetherin. While both RBF206 Vpu and Nef exert anti-tetherin activity in transient-transfection assays, mainly Vpu promotes RBF206 release in infected CD4+ T cells. Although mutations distinct from the adaptive changes observed in group M Vpus (M-Vpus) were critical for the acquisition of its anti-tetherin activity, RBF206 O-Vpu potently suppresses NF-κB activation and reduces CD4 cell surface expression. Interestingly, RBF206 Vpu counteracts tetherin in a largely species-independent manner, degrading both the long and short isoforms of human tetherin. Downmodulation of CD4, but not counteraction of tetherin, by RBF206 Vpu was dependent on the cellular ubiquitin ligase machinery. Our data present the first example of an HIV-1 group O Vpu that efficiently antagonizes human tetherin and suggest that counteraction by O-Nefs may be suboptimal. IMPORTANCE Previous studies showed that HIV-1 groups M and O evolved two alternative strategies to counteract the human ortholog of the restriction factor tetherin. While HIV-1 group M switched from Nef to Vpu due to a deletion in the cytoplasmic domain of human tetherin, HIV-1 group O, which lacks Vpu-mediated anti-tetherin activity, acquired a Nef protein that is able to target a region adjacent to the deletion. Here we report an unusual exception, identifying a strain of

48 CFR 1552.209-73 - Notification of conflicts of interest regarding personnel.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Notification of conflicts of interest regarding personnel. 1552.209-73 Section 1552.209-73 Federal Acquisition Regulations... guard services, or electrical services, provisions which shall conform substantially to the language of...

48 CFR 1552.209-73 - Notification of conflicts of interest regarding personnel.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Notification of conflicts of interest regarding personnel. 1552.209-73 Section 1552.209-73 Federal Acquisition Regulations... guard services, or electrical services, provisions which shall conform substantially to the language of...

48 CFR 1552.209-73 - Notification of conflicts of interest regarding personnel.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Notification of conflicts of interest regarding personnel. 1552.209-73 Section 1552.209-73 Federal Acquisition Regulations... guard services, or electrical services, provisions which shall conform substantially to the language of...

48 CFR 1552.209-73 - Notification of conflicts of interest regarding personnel.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Notification of conflicts of interest regarding personnel. 1552.209-73 Section 1552.209-73 Federal Acquisition Regulations... guard services, or electrical services, provisions which shall conform substantially to the language of...

38 CFR 1.552 - Public access to information that affects the public when not published in the Federal Register...

Code of Federal Regulations, 2010 CFR

2010-07-01

... information that affects the public when not published in the Federal Register as constructive notice. 1.552... Public access to information that affects the public when not published in the Federal Register as... Affairs but not published in the Federal Register, and administrative manuals and staff instructions that...

48 CFR 1552.237-74 - Publicity.

Code of Federal Regulations, 2011 CFR

2011-10-01

... Section 1552.237-74 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND... removal or remedial activities under the Comprehensive Environmental Response, Compensation and Liability... on-scene coordinator (or Project Officer) prior to releasing any information to the news media...

48 CFR 1552.237-74 - Publicity.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Section 1552.237-74 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND... removal or remedial activities under the Comprehensive Environmental Response, Compensation and Liability... on-scene coordinator (or Project Officer) prior to releasing any information to the news media...

48 CFR 1552.237-74 - Publicity.

Code of Federal Regulations, 2014 CFR

2014-10-01

... Section 1552.237-74 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND... removal or remedial activities under the Comprehensive Environmental Response, Compensation and Liability... any information to the news media regarding the removal or remedial activities being conducted under...

48 CFR 1552.237-74 - Publicity.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Section 1552.237-74 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND... removal or remedial activities under the Comprehensive Environmental Response, Compensation and Liability... on-scene coordinator (or Project Officer) prior to releasing any information to the news media...

48 CFR 1552.237-74 - Publicity.

Code of Federal Regulations, 2013 CFR

2013-10-01

... Section 1552.237-74 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND... removal or remedial activities under the Comprehensive Environmental Response, Compensation and Liability... any information to the news media regarding the removal or remedial activities being conducted under...

The pap Operon of Avian Pathogenic Escherichia coli Strain O1:K1 Is Located on a Novel Pathogenicity Island

PubMed Central

Kariyawasam, Subhashinie; Johnson, Timothy J.; Nolan, Lisa K.

2006-01-01

We have identified a 56-kb pathogenicity island (PAI) in avian pathogenic Escherichia coli strain O1:K1 (APEC-O1). This PAI, termed PAI IAPEC-O1, is integrated adjacent to the 3′ end of the pheV tRNA gene. It carries putative virulence genes of APEC (pap operon), other E. coli genes (tia and ireA), and a 1.5-kb region unique to APEC-O1. The kps gene cluster required for the biosynthesis of polysialic acid capsule was mapped to a location immediately downstream of this PAI. PMID:16369033

Surface antigens from Escherichia coli O2 and O78 strains of avian origin.

PubMed Central

Dho-Moulin, M; van den Bosch, J F; Girardeau, J P; Brée, A; Barat, T; Lafont, J P

1990-01-01

Fimbriae from O2 and O78 virulent strains of avian Escherichia coli were compared with type 1A fimbriae with regard to the apparent molecular weights of their subunits and their antigenic relationships. Under static broth culture conditions, most O78 strains expressed fimbriae closely related to those of type 1A. Under the same culture conditions, another type of fimbriae, sharing some common properties with type 1A fimbriae, was observed only on O2 strains; however, these fimbriae differed from type 1A fimbriae in the apparent molecular weights of their subunits and in the expression of specific epitopes. They were called type 1-like fimbriae. Homologies in lipopolysaccharide and outer membrane protein profiles were also demonstrated among the strains expressing type 1-like fimbriae, which suggests the existence of a clonal relationship among O2:K1 avian E. coli strains. The O78 strains studied did not appear to be clonally related. Images PMID:1968434

Comparative Genomic Analysis Shows That Avian Pathogenic Escherichia coli Isolate IMT5155 (O2:K1:H5; ST Complex 95, ST140) Shares Close Relationship with ST95 APEC O1:K1 and Human ExPEC O18:K1 Strains

PubMed Central

Pan, Zihao; Hu, Lin; Wang, Shaohui; Wang, Haojin; Leung, Frederick C.; Dai, Jianjun; Fan, Hongjie

2014-01-01

Avian pathogenic E. coli and human extraintestinal pathogenic E. coli serotypes O1, O2 and O18 strains isolated from different hosts are generally located in phylogroup B2 and ST complex 95, and they share similar genetic characteristics and pathogenicity, with no or minimal host specificity. They are popular objects for the study of ExPEC genetic characteristics and pathogenesis in recent years. Here, we investigated the evolution and genetic blueprint of APEC pathotype by performing phylogenetic and comparative genome analysis of avian pathogenic E. coli strain IMT5155 (O2:K1:H5; ST complex 95, ST140) with other E. coli pathotypes. Phylogeny analyses indicated that IMT5155 has closest evolutionary relationship with APEC O1, IHE3034, and UTI89. Comparative genomic analysis showed that IMT5155 and APEC O1 shared significant genetic overlap/similarities with human ExPEC dominant O18:K1 strains (IHE3034 and UTI89). Furthermore, the unique PAI I5155 (GI-12) was identified and found to be conserved in APEC O2 serotype isolates. GI-7 and GI-16 encoding two typical T6SSs in IMT5155 might be useful markers for the identification of ExPEC dominant serotypes (O1, O2, and O18) strains. IMT5155 contained a ColV plasmid p1ColV5155, which defined the APEC pathotype. The distribution analysis of 10 sequenced ExPEC pan-genome virulence factors among 47 sequenced E. coli strains provided meaningful information for B2 APEC/ExPEC-specific virulence factors, including several adhesins, invasins, toxins, iron acquisition systems, and so on. The pathogenicity tests of IMT5155 and other APEC O1:K1 and O2:K1 serotypes strains (isolated in China) through four animal models showed that they were highly virulent for avian colisepticemia and able to cause septicemia and meningitis in neonatal rats, suggesting zoonotic potential of these APEC O1:K1 and O2:K1 isolates. PMID:25397580

Comparative genomic analysis shows that avian pathogenic Escherichia coli isolate IMT5155 (O2:K1:H5; ST complex 95, ST140) shares close relationship with ST95 APEC O1:K1 and human ExPEC O18:K1 strains.

PubMed

Zhu Ge, Xiangkai; Jiang, Jingwei; Pan, Zihao; Hu, Lin; Wang, Shaohui; Wang, Haojin; Leung, Frederick C; Dai, Jianjun; Fan, Hongjie

2014-01-01

Avian pathogenic E. coli and human extraintestinal pathogenic E. coli serotypes O1, O2 and O18 strains isolated from different hosts are generally located in phylogroup B2 and ST complex 95, and they share similar genetic characteristics and pathogenicity, with no or minimal host specificity. They are popular objects for the study of ExPEC genetic characteristics and pathogenesis in recent years. Here, we investigated the evolution and genetic blueprint of APEC pathotype by performing phylogenetic and comparative genome analysis of avian pathogenic E. coli strain IMT5155 (O2:K1:H5; ST complex 95, ST140) with other E. coli pathotypes. Phylogeny analyses indicated that IMT5155 has closest evolutionary relationship with APEC O1, IHE3034, and UTI89. Comparative genomic analysis showed that IMT5155 and APEC O1 shared significant genetic overlap/similarities with human ExPEC dominant O18:K1 strains (IHE3034 and UTI89). Furthermore, the unique PAI I5155 (GI-12) was identified and found to be conserved in APEC O2 serotype isolates. GI-7 and GI-16 encoding two typical T6SSs in IMT5155 might be useful markers for the identification of ExPEC dominant serotypes (O1, O2, and O18) strains. IMT5155 contained a ColV plasmid p1ColV5155, which defined the APEC pathotype. The distribution analysis of 10 sequenced ExPEC pan-genome virulence factors among 47 sequenced E. coli strains provided meaningful information for B2 APEC/ExPEC-specific virulence factors, including several adhesins, invasins, toxins, iron acquisition systems, and so on. The pathogenicity tests of IMT5155 and other APEC O1:K1 and O2:K1 serotypes strains (isolated in China) through four animal models showed that they were highly virulent for avian colisepticemia and able to cause septicemia and meningitis in neonatal rats, suggesting zoonotic potential of these APEC O1:K1 and O2:K1 isolates.

48 CFR 1552.245-70 - Government property.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Government property. 1552... Government property. As prescribed in 1545.107(a), insert a clause substantially the same as follows: Government Property (SEP 2009) (a) The contractor shall not fabricate or acquire, on behalf of the Government...

48 CFR 1552.245-70 - Government property.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Government property. 1552... Government property. As prescribed in 1545.107(a), insert a clause substantially the same as follows: Government Property (SEP 2009) (a) The contractor shall not fabricate or acquire, on behalf of the Government...

48 CFR 1552.245-70 - Government property.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Government property. 1552... Government property. As prescribed in 1545.107(a), insert a clause substantially the same as follows: Government Property Government Property (a) The contractor shall not fabricate or acquire, on behalf of the...

48 CFR 1552.245-70 - Government property.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Government property. 1552... Government property. As prescribed in 1545.107(a), insert a clause substantially the same as follows: Government Property Government Property (a) The contractor shall not fabricate or acquire, on behalf of the...

Electric field induced lattice strain in pseudocubic Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-modified BaTiO{sub 3}-BiFeO{sub 3} piezoelectric ceramics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fujii, Ichiro, E-mail: ifujii@rins.ryukoku.ac.jp; Iizuka, Ryo; Ueno, Shintaro

2016-04-25

Contributions to the piezoelectric response in pseudocubic 0.3BaTiO{sub 3}-0.1Bi(Mg{sub 1/2}Ti{sub 1/2})O{sub 3}-0.6BiFeO{sub 3} ceramics were investigated by synchrotron X-ray diffraction under electric fields. All of the lattice strain determined from the 110, 111, and 200 pseudocubic diffraction peaks showed similar lattice strain hysteresis that was comparable to the bulk butterfly-like strain curve. It was suggested that the hysteresis of the lattice strain and the lack of anisotropy were related to the complex domain structure and the phase boundary composition.

Molecular characterization and drug susceptibility of non-O1/O139 V. cholerae strains of seafood, environmental and clinical origin, Italy.

PubMed

Ottaviani, Donatella; Medici, Laura; Talevi, Giulia; Napoleoni, Maira; Serratore, Patrizia; Zavatta, Emanuele; Bignami, Giorgia; Masini, Laura; Chierichetti, Serena; Fisichella, Stefano; Leoni, Francesca

2018-06-01

Toxigenic and antimicrobial susceptibility patterns and genetic relatedness of 42 non-O1/O139 V. cholerae strains, the majority of them isolated from seafood and marine water of the Adriatic sea, Italy, and 9 clinical strains, two of which with seawater of the Adriatic as the source of infection, were studied. All strains had hlyA El Tor gene but lacked ctxA gene. Four and two isolates, respectively, also had stn/sto and tcpA Class genes. More than 90% of strains showed susceptibility to cefotaxime, ciprofloxacin, cloramphenicol, tetracycline, trimethoprim + sulfamethoxazole and intermediate or full resistance to tetracycline and erythromycin. Six strains of seafood and clinical source were multi-drug resistant. PFGE analysis allowed to type all the strains with 50 banding patterns. Twenty-one strains, 11 and 8 from seafood and seawater, respectively, and 2 of clinical origin, were grouped into 9 different clusters. We report the presence of toxigenic and multidrug resistant non-O1/O139 V. cholerae strains in Adriatic, some of which genetically related, and support that they represent a potential reservoir of toxin and antibiotic resistance genes. Copyright © 2017 Elsevier Ltd. All rights reserved.

48 CFR 1552.237-71 - Technical direction.

Code of Federal Regulations, 2010 CFR

2010-10-01

.... (d) Technical direction will be issued in writing or confirmed in writing within five (5) days after... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Technical direction. 1552... Technical direction. As prescribed in 1537.110, insert a clause substantially the same as the following...

49 CFR 1552.21 - Scope and definitions.

Code of Federal Regulations, 2013 CFR

2013-10-01

..., DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY FLIGHT SCHOOLS Flight School Security Awareness Training § 1552.21 Scope and definitions. (a) Scope. This subpart applies to flight schools that provide instruction under 49 U.S.C. Subtitle VII, Part A, in the operation of aircraft or aircraft simulators, and to...

49 CFR 1552.21 - Scope and definitions.

Code of Federal Regulations, 2012 CFR

2012-10-01

..., DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY FLIGHT SCHOOLS Flight School Security Awareness Training § 1552.21 Scope and definitions. (a) Scope. This subpart applies to flight schools that provide instruction under 49 U.S.C. Subtitle VII, Part A, in the operation of aircraft or aircraft simulators, and to...

49 CFR 1552.21 - Scope and definitions.

Code of Federal Regulations, 2011 CFR

2011-10-01

..., DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY FLIGHT SCHOOLS Flight School Security Awareness Training § 1552.21 Scope and definitions. (a) Scope. This subpart applies to flight schools that provide instruction under 49 U.S.C. Subtitle VII, Part A, in the operation of aircraft or aircraft simulators, and to...

49 CFR 1552.21 - Scope and definitions.

Code of Federal Regulations, 2014 CFR

2014-10-01

..., DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY FLIGHT SCHOOLS Flight School Security Awareness Training § 1552.21 Scope and definitions. (a) Scope. This subpart applies to flight schools that provide instruction under 49 U.S.C. Subtitle VII, Part A, in the operation of aircraft or aircraft simulators, and to...

49 CFR 1552.21 - Scope and definitions.

Code of Federal Regulations, 2010 CFR

2010-10-01

..., DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY FLIGHT SCHOOLS Flight School Security Awareness Training § 1552.21 Scope and definitions. (a) Scope. This subpart applies to flight schools that provide instruction under 49 U.S.C. Subtitle VII, Part A, in the operation of aircraft or aircraft simulators, and to...

48 CFR 1552.211-74 - Work assignments.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Work assignments. 1552.211... Work assignments. As prescribed in 1511.011-74, insert the following contract clause in cost-reimbursement type term form contracts when work assignments are to be used. Work Assignments (APR 1984) (a) The...

48 CFR 1552.239-103 - Acquisition of Energy Star Compliant Microcomputers, Including Personal Computers, Monitors and...

Code of Federal Regulations, 2012 CFR

2012-10-01

... Compliant Microcomputers, Including Personal Computers, Monitors and Printers. 1552.239-103 Section 1552.239... Star Compliant Microcomputers, Including Personal Computers, Monitors and Printers. As prescribed in... Personal Computers, Monitors, and Printers (APR 1996) (a) The Contractor shall provide computer products...

48 CFR 1552.239-103 - Acquisition of Energy Star Compliant Microcomputers, Including Personal Computers, Monitors and...

Code of Federal Regulations, 2011 CFR

2011-10-01

... Compliant Microcomputers, Including Personal Computers, Monitors and Printers. 1552.239-103 Section 1552.239... Star Compliant Microcomputers, Including Personal Computers, Monitors and Printers. As prescribed in... Personal Computers, Monitors, and Printers (APR 1996) (a) The Contractor shall provide computer products...

48 CFR 1552.239-103 - Acquisition of Energy Star Compliant Microcomputers, Including Personal Computers, Monitors and...

Code of Federal Regulations, 2010 CFR

2010-10-01

... Compliant Microcomputers, Including Personal Computers, Monitors and Printers. 1552.239-103 Section 1552.239... Star Compliant Microcomputers, Including Personal Computers, Monitors and Printers. As prescribed in... Personal Computers, Monitors, and Printers (APR 1996) (a) The Contractor shall provide computer products...

Prevalence of Avian-Pathogenic Escherichia coli Strain O1 Genomic Islands among Extraintestinal and Commensal E. coli Isolates

PubMed Central

Johnson, Timothy J.; Wannemuehler, Yvonne; Kariyawasam, Subhashinie; Johnson, James R.; Logue, Catherine M.

2012-01-01

Escherichia coli strains that cause disease outside the intestine are known as extraintestinal pathogenic E. coli (ExPEC) and include pathogens of humans and animals. Previously, the genome of avian-pathogenic E. coli (APEC) O1:K1:H7 strain O1, from ST95, was sequenced and compared to those of several other E. coli strains, identifying 43 genomic islands. Here, the genomic islands of APEC O1 were compared to those of other sequenced E. coli strains, and the distribution of 81 genes belonging to 12 APEC O1 genomic islands among 828 human and avian ExPEC and commensal E. coli isolates was determined. Multiple islands were highly prevalent among isolates belonging to the O1 and O18 serogroups within phylogenetic group B2, which are implicated in human neonatal meningitis. Because of the extensive genomic similarities between APEC O1 and other human ExPEC strains belonging to the ST95 phylogenetic lineage, its ability to cause disease in a rat model of sepsis and meningitis was assessed. Unlike other ST95 lineage strains, APEC O1 was unable to cause bacteremia or meningitis in the neonatal rat model and was significantly less virulent than uropathogenic E. coli (UPEC) CFT073 in a mouse sepsis model, despite carrying multiple neonatal meningitis E. coli (NMEC) virulence factors and belonging to the ST95 phylogenetic lineage. These results suggest that host adaptation or genome modifications have occurred either in APEC O1 or in highly virulent ExPEC isolates, resulting in differences in pathogenicity. Overall, the genomic islands examined provide targets for further discrimination of the different ExPEC subpathotypes, serogroups, phylogenetic types, and sequence types. PMID:22467781

Prevalence of avian-pathogenic Escherichia coli strain O1 genomic islands among extraintestinal and commensal E. coli isolates.

PubMed

Johnson, Timothy J; Wannemuehler, Yvonne; Kariyawasam, Subhashinie; Johnson, James R; Logue, Catherine M; Nolan, Lisa K

2012-06-01

Escherichia coli strains that cause disease outside the intestine are known as extraintestinal pathogenic E. coli (ExPEC) and include pathogens of humans and animals. Previously, the genome of avian-pathogenic E. coli (APEC) O1:K1:H7 strain O1, from ST95, was sequenced and compared to those of several other E. coli strains, identifying 43 genomic islands. Here, the genomic islands of APEC O1 were compared to those of other sequenced E. coli strains, and the distribution of 81 genes belonging to 12 APEC O1 genomic islands among 828 human and avian ExPEC and commensal E. coli isolates was determined. Multiple islands were highly prevalent among isolates belonging to the O1 and O18 serogroups within phylogenetic group B2, which are implicated in human neonatal meningitis. Because of the extensive genomic similarities between APEC O1 and other human ExPEC strains belonging to the ST95 phylogenetic lineage, its ability to cause disease in a rat model of sepsis and meningitis was assessed. Unlike other ST95 lineage strains, APEC O1 was unable to cause bacteremia or meningitis in the neonatal rat model and was significantly less virulent than uropathogenic E. coli (UPEC) CFT073 in a mouse sepsis model, despite carrying multiple neonatal meningitis E. coli (NMEC) virulence factors and belonging to the ST95 phylogenetic lineage. These results suggest that host adaptation or genome modifications have occurred either in APEC O1 or in highly virulent ExPEC isolates, resulting in differences in pathogenicity. Overall, the genomic islands examined provide targets for further discrimination of the different ExPEC subpathotypes, serogroups, phylogenetic types, and sequence types.

48 CFR 1552.216-70 - Award Fee.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Section 1552.216-70 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND... the award fee to be paid is determined by the Government's judgmental evaluation of the contractor's performance in terms of the criteria stated in the contract. This determination and the methodology for...

Strain-relaxation and critical thickness of epitaxial La 1.85Sr 0.15CuO 4 films

DOE PAGES

Meyer, Tricia L; Jiang, Lu; Park, Sungkyun; ...

2015-12-08

We report the thickness-dependent strain-relaxation behavior and the associated impacts upon the superconductivity in epitaxial La 1.85Sr 0.15CuO 4 films grown on different substrates, which provide a range of strain. We have found that the critical thickness for the onset of superconductivity in La 1.85Sr 0.15CuO 4 films is associated with the finite thickness effect and epitaxial strain. In particular, thin films with tensile strain greater than ~0.25% revealed no superconductivity. We attribute this phenomenon to the inherent formation of oxygen vacancies that can be minimized via strain relaxation.

49 CFR 1552.23 - Security awareness training programs.

Code of Federal Regulations, 2014 CFR

2014-10-01

... employee to identify— (i) Uniforms and other identification, if any are required at the flight school, for... SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY FLIGHT SCHOOLS Flight School Security Awareness Training § 1552.23 Security awareness training programs. (a) General. A flight...

49 CFR 1552.23 - Security awareness training programs.

Code of Federal Regulations, 2011 CFR

2011-10-01

... employee to identify— (i) Uniforms and other identification, if any are required at the flight school, for... SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY FLIGHT SCHOOLS Flight School Security Awareness Training § 1552.23 Security awareness training programs. (a) General. A flight...

49 CFR 1552.23 - Security awareness training programs.

Code of Federal Regulations, 2013 CFR

2013-10-01

... employee to identify— (i) Uniforms and other identification, if any are required at the flight school, for... SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY FLIGHT SCHOOLS Flight School Security Awareness Training § 1552.23 Security awareness training programs. (a) General. A flight...

49 CFR 1552.23 - Security awareness training programs.

Code of Federal Regulations, 2012 CFR

2012-10-01

... employee to identify— (i) Uniforms and other identification, if any are required at the flight school, for... SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY FLIGHT SCHOOLS Flight School Security Awareness Training § 1552.23 Security awareness training programs. (a) General. A flight...

49 CFR 1552.23 - Security awareness training programs.

Code of Federal Regulations, 2010 CFR

2010-10-01

... employee to identify— (i) Uniforms and other identification, if any are required at the flight school, for... SECURITY ADMINISTRATION, DEPARTMENT OF HOMELAND SECURITY CIVIL AVIATION SECURITY FLIGHT SCHOOLS Flight School Security Awareness Training § 1552.23 Security awareness training programs. (a) General. A flight...

A rapid procedure for the detection and isolation of enterohaemorrhagic Escherichia coli (EHEC) serogroup O26, O103, O111, O118, O121, O145 and O157 strains and the aggregative EHEC O104:H4 strain from ready-to-eat vegetables.

PubMed

Tzschoppe, Markus; Martin, Annett; Beutin, Lothar

2012-01-03

Human infections with Enterohaemorrhagic Escherichia coli strains (EHEC) as agents of Haemorrhagic Colitis (HC) and Haemolytic Uraemic Syndrome (HUS) are frequently associated with the consumption of EHEC contaminated foodstuffs of different origins. EHEC O26, O103, O111, O118, O121, O145 and O157 strains are responsible for the majority of HC and HUS cases worldwide. In May 2011, the emerging aggregative EHEC O104:H4 strain caused a large outbreak with high HUS incidence in northern Germany. Contaminated sprouted seeds were suspected to be the vehicles of transmission. The examination of vegetables retailed for raw consumption revealed low numbers of E. coli (<100 cfu/g) together with high titres of Enterobacteriaceae and Pseudomonas (approx. 5.6 × 10⁷ cfu/g). Specific methods of EHEC detection adapted to vegetables are not yet published. Therefore, we have developed a rapid and sensitive method for detecting low EHEC contamination in vegetables (1-10 cfu/25 g) with artificially EHEC contaminated ready-to-eat salads. A 6-hour enrichment period in BRILA-broth was sufficient to detect 1-10 EHEC from spiked samples after plating 0.1 ml portions of enrichment culture on selective TBX-agar and CHROMagar STEC plates that were incubated at 44 °C overnight. Unlike EHEC strains, the growth of bacteria of the plant flora was substantially inhibited at 44 °C. DNA for real-time PCR detection of EHEC characteristic genes (stx(1), stx(2), eae, ehxA, and O-antigen associated) was prepared with bacteria grown on TBX-agar plates. The storage of EHEC inoculated salad samples for 72 h at 6 °C resulted in a significant reduction (mean value 14.6%) of detectable EHEC, suggesting interference of EHEC with the resident plant microflora. CHROMagar STEC was evaluated as a selective medium for the detection of EHEC strains. Growth on CHROMagar STEC was closely associated with EHEC O26:[H11], O111:[H8], O118:H16, O121:[H19], O145:[H28], O157:[H7] and aggregative EHEC O104:H4 strains

48 CFR 1552.215-75 - Past performance information.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Past performance... 1552.215-75 Past performance information. As prescribed in 1515.209(c), insert the following clause: Past Performance Information (OCT 2000) (a) Offerors shall submit the information requested below as...

48 CFR 1552.237-76 - Government-Contractor Relations.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Government-Contractor... 1552.237-76 Government-Contractor Relations. As prescribed in 1537.110(g), insert the following clause: Government-Contractor Relations (JUN 1999) (a) The Government and the Contractor understand and agree that...

48 CFR 1552.237-76 - Government-Contractor Relations.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Government-Contractor... 1552.237-76 Government-Contractor Relations. As prescribed in 1537.110(g), insert the following clause: Government-Contractor Relations (JUN 1999) (a) The Government and the Contractor understand and agree that...

48 CFR 1552.237-76 - Government-Contractor Relations.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Government-Contractor... 1552.237-76 Government-Contractor Relations. As prescribed in 1537.110(g), insert the following clause: Government-Contractor Relations (JUN 1999) (a) The Government and the Contractor understand and agree that...

48 CFR 1552.211-76 - Legal analysis.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Legal analysis. 1552.211... Legal analysis. As prescribed in 1511.011-76, insert this contract clause when it is determined that the contract involves legal analysis. Legal Analysis (APR 1984) The Contractor shall furnish to the Contracting...

48 CFR 1552.211-76 - Legal analysis.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Legal analysis. 1552.211... Legal analysis. As prescribed in 1511.011-76, insert this contract clause when it is determined that the contract involves legal analysis. Legal Analysis (APR 1984) The Contractor shall furnish to the Contracting...

48 CFR 1552.211-76 - Legal analysis.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Legal analysis. 1552.211... Legal analysis. As prescribed in 1511.011-76, insert this contract clause when it is determined that the contract involves legal analysis. Legal Analysis (APR 1984) The Contractor shall furnish to the Project...

48 CFR 1552.211-76 - Legal analysis.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Legal analysis. 1552.211... Legal analysis. As prescribed in 1511.011-76, insert this contract clause when it is determined that the contract involves legal analysis. Legal Analysis (APR 1984) The Contractor shall furnish to the Project...

Clonal relationship among Vibrio cholerae O1 El Tor strains isolated in Somalia.

PubMed

Scrascia, Maria; Pugliese, Nicola; Maimone, Francesco; Mohamud, Kadigia A; Grimont, Patrick A D; Materu, Sadiki F; Pazzani, Carlo

2009-03-01

One hundred and three Vibrio cholerae O1 strains, selected to represent the cholera outbreaks which occurred in Somalia in 1998-1999, were characterized by random amplified polymorphic DNA patterns, ribotyping, and antimicrobial susceptibility. All strains showed a unique amplified DNA pattern and 2 closely related ribotypes (B5a and B8a), among which B5a was the more frequently identified. Ninety-one strains were resistant to ampicillin, chloramphenicol, spectinomycin, streptomycin, sulfamethoxazole, and trimethoprim, conferred, except for spectinomycin, by a conjugative plasmid IncC. These findings indicated that the group of strains active in Somalia in the late 1990s had a clonal origin.

Genetic diversity of environmental Vibrio cholerae O1 strains isolated in Northern Vietnam.

PubMed

Takemura, Taichiro; Murase, Kazunori; Maruyama, Fumito; Tran, Thi Luong; Ota, Atsushi; Nakagawa, Ichiro; Nguyen, Dong Tu; Ngo, Tu Cuong; Nguyen, Thi Hang; Tokizawa, Asako; Morita, Masatomo; Ohnishi, Makoto; Nguyen, Binh Minh; Yamashiro, Tetsu

2017-10-01

Cholera epidemics have been recorded periodically in Vietnam during the seventh cholera pandemic. Since cholera is a water-borne disease, systematic monitoring of environmental waters for Vibrio cholerae presence is important for predicting and preventing cholera epidemics. We conducted monitoring, isolation, and genetic characterization of V. cholerae strains in Nam Dinh province of Northern Vietnam from Jul 2013 to Feb 2015. In this study, four V. cholerae O1 strains were detected and isolated from 110 analyzed water samples (3.6%); however, none of them carried the cholera toxin gene, ctxA, in their genomes. Whole genome sequencing and phylogenetic analysis revealed that the four O1 isolates were separated into two independent clusters, and one of them diverged from a common ancestor with pandemic strains. The analysis of pathogenicity islands (CTX prophage, VPI-I, VPI-II, VSP-I, and VSP-II) indicated that one strain (VNND_2014Jun_6SS) harbored an unknown prophage-like sequence with high homology to vibriophage KSF-1 phi and VCY phi, identified from Bangladesh and the USA, respectively, while the other three strains carried tcpA gene with a distinct sequence demonstrating a separate clonal lineage. These results suggest that the aquatic environment can harbor highly divergent V. cholera strains and serve as a reservoir for multiple V. cholerae virulence-associated genes which may be exchanged via mobile genetic elements. Therefore, continuous monitoring and genetic characterization of V. cholerae strains in the environment should contribute to the early detection of the sources of infection and prevention of cholera outbreaks as well as to understanding the natural ecology and evolution of V. cholerae. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

48 CFR 1552.216-77 - Award term incentive.

Code of Federal Regulations, 2010 CFR

2010-10-01

... performance measures for the corresponding evaluation period; or (iii) The Government notifies the contractor....216-77 Section 1552.216-77 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY...) based on overall contractor performance as evaluated in accordance with the Clause entitled “Award Term...

48 CFR 1552.242-72 - Financial administrative contracting officer.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Financial administrative... Clauses 1552.242-72 Financial administrative contracting officer. As prescribed in 1542.705 (b), insert the following clause: Financial Administrative Contracting Officer (OCT 2000) (a) A Financial...

48 CFR 1552.235-75 - Access to Toxic Substances Control Act Confidential Business Information (APR 1996).

Code of Federal Regulations, 2010 CFR

2010-10-01

... Control Act Confidential Business Information (APR 1996). 1552.235-75 Section 1552.235-75 Federal... Confidential Business Information (APR 1996). As prescribed in 1535.007(b), insert the following provision: Access to Toxic Substances Control Act Confidential Business Information (APR 1996) In order to perform...

Molecular identification of pathogenicity genes and ERIC types in Vibrio cholerae O1 epidemic strains from Mozambique.

PubMed Central

Folgosa, E.; Mastrandrea, S.; Cappuccinelli, P.; Uzzau, S.; Rappelli, P.; Brian, M. J.; Colombo, M. M.

2001-01-01

The phenotypic and genotypic profiles of the V. cholerae strains causing the Mozambican 1997-8 epidemic were characterized to provide a reference for comparison with other epidemic strains. A total of 75 strains of V. cholerae O1 isolated in different provinces, were analysed. Strains were characterized by PCR for detecting toxin genes (ctxA, zot and ace), virulence associated genes (tcpA. nanH, hlyA and torR) and ERIC sequences. All V. cholerae strains were serotype O1, Ogawa, biotype El Tor. MIC testing showed a high proportion of strains multi-resistant to drugs (100% to cotrimoxazole and 52% to tetracycline) and susceptibility to ciprofloxacin. The isolates contained two intact copies of the CTX genetic element and all other genes tested. PCR of restricted DNA revealed two ERIC types: the first in provincial isolates, also predominant in other African epidemic strains, and the second in Maputo isolates (the national capital). PMID:11561970

48 CFR 1552.211-78 - Management consulting services.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Management consulting... 1552.211-78 Management consulting services. As prescribed in 1511.011-78, insert the following contract clause in all contracts for management consulting services. Management Consulting Services (APR 1985) All...

Electric-field-induced strain contributions in morphotropic phase boundary composition of (Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-BaTiO{sub 3} during poling

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khansur, Neamul H.; Daniels, John E.; Hinterstein, Manuel

2015-12-14

The microscopic contributions to the electric-field-induced macroscopic strain in a morphotropic 0.93(Bi{sub 1/2}Na{sub 1/2}TiO{sub 3})−0.07(BaTiO{sub 3}) with a mixed rhombohedral and tetragonal structure have been quantified using full pattern Rietveld refinement of in situ high-energy x-ray diffraction data. The analysis methodology allows a quantification of all strain mechanisms for each phase in a morphotropic composition and is applicable to use in a wide variety of piezoelectric compositions. It is shown that during the poling of this material 24%, 44%, and 32% of the total macroscopic strain is generated from lattice strain, domain switching, and phase transformation strains, respectively. The resultsmore » also suggest that the tetragonal phase contributes the most to extrinsic domain switching strain, whereas the lattice strain primarily stems from the rhombohedral phase. The analysis also suggests that almost 32% of the total strain is lost or is a one-time effect due to the irreversible nature of the electric-field-induced phase transformation in the current composition. This information is relevant to on-going compositional development strategies to harness the electric-field-induced phase transformation strain of (Bi{sub 1/2}Na{sub 1/2})TiO{sub 3}-based lead-free piezoelectric materials for actuator applications.« less

48 CFR 1552.235-77 - Data Security for Federal Insecticide, Fungicide and Rodenticide Act Confidential Business...

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Data Security for Federal... 1552.235-77 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 1552.235-77 Data Security for...

48 CFR 1552.235-77 - Data Security for Federal Insecticide, Fungicide and Rodenticide Act Confidential Business...

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Data Security for Federal... 1552.235-77 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 1552.235-77 Data Security for...

48 CFR 1552.235-77 - Data Security for Federal Insecticide, Fungicide and Rodenticide Act Confidential Business...

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Data Security for Federal... 1552.235-77 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 1552.235-77 Data Security for...

48 CFR 1552.235-77 - Data Security for Federal Insecticide, Fungicide and Rodenticide Act Confidential Business...

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Data Security for Federal... 1552.235-77 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 1552.235-77 Data Security for...

48 CFR 1552.235-77 - Data Security for Federal Insecticide, Fungicide and Rodenticide Act Confidential Business...

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Data Security for Federal... 1552.235-77 Federal Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 1552.235-77 Data Security for...

The genome sequence of avian pathogenic Escherichia coli strain O1:K1:H7 shares strong similarities with human extraintestinal pathogenic E. coli genomes.

PubMed

Johnson, Timothy J; Kariyawasam, Subhashinie; Wannemuehler, Yvonne; Mangiamele, Paul; Johnson, Sara J; Doetkott, Curt; Skyberg, Jerod A; Lynne, Aaron M; Johnson, James R; Nolan, Lisa K

2007-04-01

Escherichia coli strains that cause disease outside the intestine are known as extraintestinal pathogenic E. coli (ExPEC) and include human uropathogenic E. coli (UPEC) and avian pathogenic E. coli (APEC). Regardless of host of origin, ExPEC strains share many traits. It has been suggested that these commonalities may enable APEC to cause disease in humans. Here, we begin to test the hypothesis that certain APEC strains possess potential to cause human urinary tract infection through virulence genotyping of 1,000 APEC and UPEC strains, generation of the first complete genomic sequence of an APEC (APEC O1:K1:H7) strain, and comparison of this genome to all available human ExPEC genomic sequences. The genomes of APEC O1 and three human UPEC strains were found to be remarkably similar, with only 4.5% of APEC O1's genome not found in other sequenced ExPEC genomes. Also, use of multilocus sequence typing showed that some of the sequenced human ExPEC strains were more like APEC O1 than other human ExPEC strains. This work provides evidence that at least some human and avian ExPEC strains are highly similar to one another, and it supports the possibility that a food-borne link between some APEC and UPEC strains exists. Future studies are necessary to assess the ability of APEC to overcome the hurdles necessary for such a food-borne transmission, and epidemiological studies are required to confirm that such a phenomenon actually occurs.

Non-toxigenic environmental Vibrio cholerae O1 strain from Haiti provides evidence of pre-pandemic cholera in Hispaniola.

PubMed

Azarian, Taj; Ali, Afsar; Johnson, Judith A; Jubair, Mohammad; Cella, Eleonora; Ciccozzi, Massimo; Nolan, David J; Farmerie, William; Rashid, Mohammad H; Sinha-Ray, Shrestha; Alam, Meer T; Morris, J Glenn; Salemi, Marco

2016-10-27

Vibrio cholerae is ubiquitous in aquatic environments, with environmental toxigenic V. cholerae O1 strains serving as a source for recurrent cholera epidemics and pandemic disease. However, a number of questions remain about long-term survival and evolution of V. cholerae strains within these aquatic environmental reservoirs. Through monitoring of the Haitian aquatic environment following the 2010 cholera epidemic, we isolated two novel non-toxigenic (ctxA/B-negative) Vibrio cholerae O1. These two isolates underwent whole-genome sequencing and were investigated through comparative genomics and Bayesian coalescent analysis. These isolates cluster in the evolutionary tree with strains responsible for clinical cholera, possessing genomic components of 6 th and 7 th pandemic lineages, and diverge from "modern" cholera strains around 1548 C.E. [95% HPD: 1532-1555]. Vibrio Pathogenicity Island (VPI)-1 was present; however, SXT/R391-family ICE and VPI-2 were absent. Rugose phenotype conversion and vibriophage resistance evidenced adaption for persistence in aquatic environments. The identification of V. cholerae O1 strains in the Haitian environment, which predate the first reported cholera pandemic in 1817, broadens our understanding of the history of pandemics. It also raises the possibility that these and similar environmental strains could acquire virulence genes from the 2010 Haitian epidemic clone, including the cholera toxin producing CTXϕ.

48 CFR 1552.223-70 - Protection of human subjects.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Protection of human... 1552.223-70 Protection of human subjects. As prescribed in 1523.303-70, insert the following contract clause when the contract involves human test subjects. Protection of Human Subjects (APR 1984) (a) The...

48 CFR 1552.223-70 - Protection of human subjects.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Protection of human... 1552.223-70 Protection of human subjects. As prescribed in 1523.303-70, insert the following contract clause when the contract involves human test subjects. Protection of Human Subjects (APR 1984) (a) The...

48 CFR 1552.223-70 - Protection of human subjects.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Protection of human... 1552.223-70 Protection of human subjects. As prescribed in 1523.303-70, insert the following contract clause when the contract involves human test subjects. Protection of Human Subjects (APR 1984) (a) The...

48 CFR 1552.223-70 - Protection of human subjects.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Protection of human... 1552.223-70 Protection of human subjects. As prescribed in 1523.303-70, insert the following contract clause when the contract involves human test subjects. Protection of Human Subjects (APR 1984) (a) The...

48 CFR 1552.223-70 - Protection of human subjects.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 48 Federal Acquisition Regulations System 6 2014-10-01 2014-10-01 false Protection of human... 1552.223-70 Protection of human subjects. As prescribed in 1523.303-70, insert the following contract clause when the contract involves human test subjects. Protection of Human Subjects (APR 1984) (a) The...

48 CFR 1552.209-71 - Organizational conflicts of interest.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Organizational conflicts... Clauses 1552.209-71 Organizational conflicts of interest. As prescribed in 1509.507-2, insert the... accomplished through simplified acquisition procedures, use of the clause is optional. Organizational Conflicts...

48 CFR 1552.215-74 - Advanced understanding-uncompensated time.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Advanced understanding... Clauses 1552.215-74 Advanced understanding—uncompensated time. As prescribed in 1515.408(b), insert the following provision or one substantially the same as the following provision: Advanced Understanding...

48 CFR 1552.211-70 - Reports of work.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Reports of work. 1552.211... Reports of work. As prescribed in 1511.011-70, insert one of the contract clauses in this subsection when... is to be used to specify reports in the contract schedule. Reports of Work (OCT 2000) The Contractor...

48 CFR 1552.217-72 - Option to extend the term of the contract-cost-plus-award-fee contract.

Code of Federal Regulations, 2010 CFR

2010-10-01

... of the contract-cost-plus-award-fee contract. 1552.217-72 Section 1552.217-72 Federal Acquisition...-award-fee contract. As prescribed in 1517.208(c), insert this contract clause in cost-plus-award-fee... Term of the Contract—Cost-Plus-Award-Fee Contract (APR 1984) (a) The Government has the option to...

17 CFR 155.2 - Trading standards for floor brokers.

Code of Federal Regulations, 2013 CFR

2013-04-01

... TRADING STANDARDS § 155.2 Trading standards for floor brokers. Each contract market shall adopt rules which shall, at a minimum, with respect to each member of the contract market acting as a floor broker... option, or (3) sale of any put option, in the same commodity which is executable at the market price or...

17 CFR 155.2 - Trading standards for floor brokers.

Code of Federal Regulations, 2014 CFR

2014-04-01

... (CONTINUED) TRADING STANDARDS § 155.2 Trading standards for floor brokers. Each contract market shall adopt rules which shall, at a minimum, with respect to each member of the contract market acting as a floor... option, or (3) sale of any put option, in the same commodity which is executable at the market price or...

48 CFR 1552.219-73 - Small Disadvantaged Business Targets.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) and EPAAR 1552.219-72, the following small disadvantaged business (SDB) participation targets proposed... specifically identified SDB(s) was (were) considered under the Section—SDB participation evaluation factor or... promptly notify the contracting officer of any substitution of firms if the new firms are not SDB concerns...

48 CFR 1552.219-73 - Small Disadvantaged Business Targets.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) and EPAAR 1552.219-72, the following small disadvantaged business (SDB) participation targets proposed... specifically identified SDB(s) was (were) considered under the Section—SDB participation evaluation factor or... promptly notify the contracting officer of any substitution of firms if the new firms are not SDB concerns...

48 CFR 1552.219-73 - Small Disadvantaged Business Targets.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) and EPAAR 1552.219-72, the following small disadvantaged business (SDB) participation targets proposed... specifically identified SDB(s) was (were) considered under the Section—SDB participation evaluation factor or... promptly notify the contracting officer of any substitution of firms if the new firms are not SDB concerns...

48 CFR 1552.219-73 - Small Disadvantaged Business Targets.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) and EPAAR 1552.219-72, the following small disadvantaged business (SDB) participation targets proposed... specifically identified SDB(s) was (were) considered under the Section—SDB participation evaluation factor or... promptly notify the contracting officer of any substitution of firms if the new firms are not SDB concerns...

48 CFR 1552.219-73 - Small Disadvantaged Business Targets.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) and EPAAR 1552.219-72, the following small disadvantaged business (SDB) participation targets proposed... specifically identified SDB(s) was (were) considered under the Section—SDB participation evaluation factor or... promptly notify the contracting officer of any substitution of firms if the new firms are not SDB concerns...

Investigation of the interface characteristics of Y2O3/GaAs under biaxial strain, triaxial strain, and non-strain conditions

NASA Astrophysics Data System (ADS)

Shi, Li-Bin; Liu, Xu-Yang; Dong, Hai-Kuan

2016-09-01

We investigate the interface behaviors of Y2O3/GaAs under biaxial strain, triaxial strain, and non-strain conditions. This study is performed by first principles calculations based on density functional theory (DFT). First of all, the biaxial strain is realized by changing the lattice constants in ab plane. Averaged electrostatic potential (AEP) is aligned by establishing Y2O3 and GaAs (110) surfaces. The band offsets of Y2O3/GaAs interface under biaxial strain are investigated by generalized gradient approximation and Heyd-Scuseria-Ernzerhof (HSE) functionals. The interface under biaxial strain is suitable for the design of metal oxide semiconductor (MOS) devices because the valence band offsets (VBO) and conduction band offsets (CBO) are larger than 1 eV. Second, the triaxial strain is applied to Y2O3/GaAs interface by synchronously changing the lattice constants in a, b, and c axis. The band gaps of Y2O3 and GaAs under triaxial strain are investigated by HSE functional. We compare the VBO and CBO under triaxial strain with those under biaxial strain. Third, in the absence of lattice strain, the formation energies, charge state switching levels, and migration barriers of native defects in Y2O3 are assessed. We investigate how they will affect the MOS device performance. It is found that VO+2 and Oi-2 play a very dangerous role in MOS devices. Finally, a direct tunneling leakage current model is established. The model is used to analyze current and voltage characteristics of the metal/Y2O3/GaAs.

Multiphase nanodomains in a strained BaTiO3 film on a GdScO3 substrate

NASA Astrophysics Data System (ADS)

Kobayashi, Shunsuke; Inoue, Kazutoshi; Kato, Takeharu; Ikuhara, Yuichi; Yamamoto, Takahisa

2018-02-01

Controlling the crystal structure of ferroelectric materials via epitaxial strain, which is a well-known technique in strain engineering, can lead to the formation of unique domain structures generating non-intrinsic phenomena such as electronic conductivity, photovoltages, and enhanced piezoelectric characteristics. Strained BaTiO3 films are promising ferroelectric materials as theoretical modeling predicts that different domain morphologies can introduce additional properties not observed in conventional BaTiO3 ceramics. To rationally design materials for practical application, a thorough understanding of the formation mechanisms and stabilities of different domain structures in strained BaTiO3 films is required. However, there have been very few experimental reports on this topic, and details about the domain structures in strained BaTiO3 films are currently lacking. In this paper, we report multiphase nanodomains in a strained BaTiO3 film deposited on an orthorhombic GdScO3 substrate. The phase-transition behavior of the strained BaTiO3 film reveals that it contains multiple phases at room temperature; the film first undergoes a phase-transition upon heating at around 550 K, and then a paraelectric phase forms at temperatures above 690 K. A picometer-scale analysis of the Ti ion displacements, using an advanced scanning transmission electron microscopy technique, is used to characterize the complex multiphase nanodomains, providing useful insights into the control of domain structures in BaTiO3 films by applying epitaxial strain.

Recent emergence of clonal group O25b:K1:H4-B2-ST131 ibeA strains among Escherichia coli poultry isolates, including CTX-M-9-producing strains, and comparison with clinical human isolates.

PubMed

Mora, Azucena; Herrera, Alexandra; Mamani, Rosalia; López, Cecilia; Alonso, María Pilar; Blanco, Jesús E; Blanco, Miguel; Dahbi, Ghizlane; García-Garrote, Fernando; Pita, Julia María; Coira, Amparo; Bernárdez, María Isabel; Blanco, Jorge

2010-11-01

To discern the possible spread of the Escherichia coli O25b:H4-ST131 clonal group in poultry and the zoonotic potential of avian strains, we made a retrospective search of our strain collection and compared the findings for those strains with the findings for current strains. Thus, we have characterized a collection of 19 avian O25b:H4-ST131 E. coli strains isolated from 1995 to 2010 which, interestingly, harbored the ibeA gene. Using this virulence gene as a criterion for selection, we compared those 19 avian strains with 33 human O25b:H4-ST131 ibeA-positive E. coli strains obtained from patients with extraintestinal infections (1993 to 2009). All 52 O25b:H4-ST131 ibeA-positive E. coli strains shared the fimH, kpsMII, malX, and usp genes but showed statistically significant differences in nine virulence factors, namely, papGIII, cdtB, sat, and kpsMII K5, which were associated with human strains, and iroN, kpsMII K1, cvaC, iss, and tsh, which were associated with strains of avian origin. The XbaI macrorestriction profiles of the 52 E. coli O25b:H4-ST131 ibeA-positive strains revealed 11 clusters (clusters I to XI) of >85% similarity, with four clusters including strains of human and avian origin. Cluster VII (90.9% similarity) grouped 10 strains (7 avian and 3 human strains) that mostly produced CTX-M-9 and that also shared the same virulence profile. Finally, we compared the macrorestriction profiles of the 12 CTX-M-9-producing O25b:H4-ST131 ibeA strains (7 avian and 5 human strains) identified among the 52 strains with those of 15 human O25b:H4-ST131 CTX-M-14-, CTX-M-15-, and CTX-M-32-producing strains that proved to be negative for ibeA and showed that they clearly differed in the level of similarity from the CTX-M-9-producing strains. In conclusion, E. coli clonal group O25b:H4-ST131 ibeA has recently emerged among avian isolates with the new acquisition of the K1 capsule antigen and includes CTX-M-9-producing strains. This clonal group represents a real

17 CFR 155.2 - Trading standards for floor brokers.

Code of Federal Regulations, 2010 CFR

2010-04-01

... TRADING STANDARDS § 155.2 Trading standards for floor brokers. Each contract market shall adopt and submit..., a set of rules which shall, at a minimum, with respect to each member of the contract market acting... the market price or at the price at which such purchase or sale can be made for the member's own...

17 CFR 155.2 - Trading standards for floor brokers.

Code of Federal Regulations, 2011 CFR

2011-04-01

... TRADING STANDARDS § 155.2 Trading standards for floor brokers. Each contract market shall adopt and submit..., a set of rules which shall, at a minimum, with respect to each member of the contract market acting... the market price or at the price at which such purchase or sale can be made for the member's own...

17 CFR 155.2 - Trading standards for floor brokers.

Code of Federal Regulations, 2012 CFR

2012-04-01

... TRADING STANDARDS § 155.2 Trading standards for floor brokers. Each contract market shall adopt and submit..., a set of rules which shall, at a minimum, with respect to each member of the contract market acting... the market price or at the price at which such purchase or sale can be made for the member's own...

The magnetic transition temperature tuned by strain in YMn0.9Ru0.1O3 thin films

NASA Astrophysics Data System (ADS)

Yang, L. P.; Zhang, A. M.; Wang, K.; Wu, X. S.; Zhai, Z. Y.

2018-05-01

Epitaxial orthorhombic YMn0.9Ru0.1O3 films with different thickness have been grown on (001)-SrTiO3 substrates by pulsed laser deposition (PLD). The crystal structure is well investigated by X-ray Diffraction. It is found that the out-of-plane parameter c slowly increases with decreasing thickness of samples because of the tensile strain between the films and substrates along c axis. The lengths of in-plane Mn-O bonds expand with the enhancement of strains, which is proved by Raman scatting. The magnetic measurements reveal that there exist two magnetic transition temperatures TN1 and TN2. The TN1 is close to that of orthorhombic YMnO3 bulk. With decreasing thickness of the films, TN1 keeps almost constant because of the small stain along c-axis. TN2, however, obviously increases from 117 K to 134 K, which could be related to the expansion of in-plane Mn-O bonds. Results show that the magnetic transition temperature of YMn0.9Ru0.1O3 films can be sensitively manipulated by the strain of the films.

Culture supernatants from V. cholerae O1 El Tor strains isolated from different geographic areas induce cell vacuolation and cytotoxicity.

PubMed

Vidal, Jorge E; Enríquez-Rincón, Fernando; Giono-Cerezo, Silvia; Ribas-Aparicio, Rosa María; Figueroa-Arredondo, Paula

2009-01-01

To investigate whether the HlyA-induced vacuolating effect is produced by V. cholerae O1 ElTor strains isolated from different geographic origins, including Mexico. Supernatant-induced haemolysis, vacuolating activity and cytotoxicity in Vero cells were recorded. PCR, RFLP analysis and molecular cloning were performed. All ElTor strains analyzed induced cellular vacuolation. Ribotype 2 strains isolates from the U.S. gulf coast yielded the highest titer of vacuolating activity. Eight of nine strains were haemolytic, while all strains were PCR positive for the hlyA gene. We cloned the hlyA gene from two ElTor strains, a toxigenic (2514-88, ctxAB+) and a non-toxigenic Mexican strain (CM 91-3, ctxAB-). Supernatant from those recombinant E. coli strains induced haemolysis, cell vacuolation and cytotoxicity. RFLP-PCR analysis revealed similarities in the hlyA gene from all strains tested. The HlyA-induced vacuolating effect is a widespread phenotype of epidemic V. cholerae O1 ElTor strains.

Whole-Genome Sequence of Aeromonas hydrophila Strain AH-1 (Serotype O11)

PubMed Central

Forn-Cuní, Gabriel; Tomás, Juan M.

2016-01-01

Aeromonas hydrophila is an emerging pathogen of aquatic and terrestrial animals, including humans. Here, we report the whole-genome sequence of the septicemic A. hydrophila AH-1 strain, belonging to the serotype O11, and the first mesophilic Aeromonas with surface layer (S-layer) to be sequenced. PMID:27587829

Prevalence and molecular characterization of Vibrio cholerae O1, non-O1 and non-O139 in tropical seafood in Cochin, India.

PubMed

Kumar, Rakesh; Lalitha, Kuttannappilly V

2013-03-01

The objective of this study was to determine the prevalence of O1, O139, and non-O1 and non-O139 Vibrio cholerae, which were associated with fresh and raw seafood samples harvested from Cochin, India waters during 2009-2011. Results from V. cholerae-specific biochemical, molecular, and serological assays identified five El Tor V. cholerae O1 Ogawa strains and 377 non-O1, non-O139 V. cholerae strains from 265 seafood samples. V. cholerae O139 strains were not isolated. Polymerase chain reaction assays confirmed the presence of V. cholerae O1 El Tor biotype in seafood. Antibiotic susceptibility analysis revealed that the V. cholerae O1 strains were pansusceptible to 20 test antibiotics, whereas 26%, 40%, 62%, and 84% of the non-O1, non-O139 V. cholerae strains were resistant to cefpodoxime, ticarcillin, augmentin, and colistin, respectively. Detection of virulence and regulatory genes in V. cholerae associated with seafood revealed the presence of virulence and regulatory genes (i.e., ctx, zot, ace, toxR genes) in V. cholerae O1 strains, nevertheless, presence of ace and toxR genes were detected in non-O1, non-O139 in 9.8 and 91% strains, respectively. In conclusion, the presence of pathogenic V. cholerae in seafood harvested from local Cochin waters warrants the introduction of a postharvest seafood monitoring program, which will lead to a greater understanding of the distribution, abundance, and virulence of diverse pathogenic Vibrio populations that inhabit these different coastal regions so that a risk management program can be established.

Prevalence of O1/K1- and O2/K3-Reactive Actinobacillus suis in Healthy and Diseased Swine

PubMed Central

Slavić, ĐurĐa; Toffner, Tania L.; Monteiro, Mario A.; Perry, Malcolm B.; MacInnes, Janet I.

2000-01-01

A cell surface antigen-typing system was devised for the swine pathogen Actinobacillus suis and used to examine the prevalence of different lipopolysaccharide (O) types in healthy and diseased pigs. The strains examined in this study were isolated from a variety of locations in Canada and from Kansas. Lipopolysaccharide preparations of 151 isolates of A. suis were characterized by immunoblotting using polyclonal antisera generated to strains SO4 (O1/K1), H89-1173 (O2/K3), and VSB 3714, a rough strain. Approximately 54% (62 of 114) of A. suis isolates from diseased pigs, all (11 of 11) isolates from healthy pigs, and all (4 of 4) reference strains reacted with O1/K1 antiserum. More than 80% (18 of 22) of A. suis strains used for bacterin production and approximately 41% (47 of 114) of isolates from diseased pigs bound O2/K3 antiserum. One isolate appeared to be rough, and five were untypeable. O1/K1- and O2/K3-reactive strains were equally prevalent in Kansas, whereas O2/K3-reactive strains were more common in Québec and western Canada and O1/K1 strains were most common in Ontario. The fact that virtually all of the strains submitted for bacterin production were O2/K3-reactive strains is consistent with the notion that these strains may be more virulent than O1/K1 strains; alternatively, this may reflect geographic or other biases. In addition, we observed cross-reactivity between A. suis cell surface antigens and swine antisera to several other important pathogens. This finding may explain why previous attempts to develop a simple serodiagnostic test for A. suis have been unsuccessful. PMID:11015398

48 CFR 1552.209-72 - Organizational conflict of interest certification.

Code of Federal Regulations, 2010 CFR

2010-10-01

... Provisions and Clauses 1552.209-72 Organizational conflict of interest certification. As prescribed in 1509... Conflict of Interest Certification (APR 1984) The offeror [] is [] is not aware of any information bearing on the existence of any potential organizational conflict of interest. If the offeror is aware of...

Characterization of enterohemorrhagic Escherichia coli O111 and O157 strains isolated from outbreak patients in Japan.

PubMed

Watahiki, Masanori; Isobe, Junko; Kimata, Keiko; Shima, Tomoko; Kanatani, Jun-ichi; Shimizu, Miwako; Nagata, Akihiro; Kawakami, Keiko; Yamada, Mikiko; Izumiya, Hidemasa; Iyoda, Sunao; Morita-Ishihara, Tomoko; Mitobe, Jiro; Terajima, Jun; Ohnishi, Makoto; Sata, Tetsutaro

2014-08-01

In April and May 2011, there was a serious food-poisoning outbreak in Japan caused by enterohemorrhagic Escherichia coli (EHEC) strains O111:H8 and O157:H7 from raw beef dishes at branches of a barbecue restaurant. This outbreak involved 181 infected patients, including 34 hemolytic-uremic syndrome (HUS) cases (19%). Among the 34 HUS patients, 21 developed acute encephalopathy (AE) and 5 died. Patient stool specimens yielded E. coli O111 and O157 strains. We also detected both EHEC O111 stx2 and stx-negative E. coli O111 strains in a stock of meat block from the restaurant. Pulsed-field gel electrophoresis (PFGE) and multilocus variable-number tandem-repeat analysis (MLVA) showed that the stx-negative E. coli O111 isolates were closely related to EHEC O111 stx2 isolates. Although the EHEC O157 strains had diverse stx gene profiles (stx1, stx2, and stx1 stx2), the PFGE and MLVA analyses indicated that these isolates originated from a single clone. Deletion of the Stx2-converting prophage from the EHEC O111 stx2 isolates was frequently observed during in vitro growth, suggesting that strain conversion from an EHEC O111 stx2 to an stx-negative strain may have occurred during infection. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Rapid screening of toxigenic vibrio cholerae O1 strains from south Iran by PCR-ELISA.

PubMed

Mousavi, Seyed Latif; Nazarian, Shahram; Amani, Jafar; Rahgerdi, Ahmad Karimi

2008-01-01

The ability to sensitively detect Vibrio cholera with PCR-ELISA method represents a considerable advancement over alternative more time-consuming methods for detection of this pathogen. The aim of this research is to evaluate the suitability of a PCR-enzyme-linked immunosorbent assay for sensitive and rapid detection of V. cholera O1. The 398-bp sequence of a gene that codes for the cholera toxin B subunit was amplified by PCR. The digoxigenin-labeled amplified products were coated on microplates and detected by ELISA. The PCR product was also hybridized with biotin labelled probe and detected by ELISA using streptavidin. The specificity of the PCR was determined using 10 bacterial strains and 50 samples from south Iran. The detection limit was 0.5 pg of the genomic DNA and five bacterial cells. Adaptation of PCR into PCR-ELISA assay format facilitates specific and sensitive detection and diagnosis of human cholera disease. We conclude that this PCR-ELISA is a diagnostic method that specifically detects toxin genes in V. cholera O1 strains. It is more rapid and less cumbersome than other diagnostic methods for detection of toxicity in these strains.

Complete Genome Sequence of a Yersinia enterocolitica “Old World” (3/O:9) Strain and Comparison with the “New World” (1B/O:8) Strain▿†

PubMed Central

Wang, Xin; Li, Yang; Jing, Huaiqi; Ren, Yan; Zhou, Zhemin; Wang, Shaojing; Kan, Biao; Xu, Jianguo; Wang, Lei

2011-01-01

Yersinia enterocolitica is a heterogeneous bacterial species with a wide range of animal reservoirs through which human intestinal illness can be facilitated. In contrast to the epidemiological pattern observed in the United States, infections in China present a pattern similar to those in European countries and Japan, wherein “Old World” strains (biotypes 2 to 5) are prevalent. To gain insights into the evolution of Y. enterocolitica and pathogenic properties toward human hosts, we sequenced the genome of a biotype 3 strain, 105.5R(r) (O:9), obtained from a Chinese patient. Comparative genome sequence analysis with strain 8081 (1B/O:8) revealed new insights into Y. enterocolitica. Both strains have more than 14% specific genes. In strain 105.5R(r), putative virulence factors were found in strain-specific genomic pathogenicity islands that comprised a novel type III secretion system and rtx-like genes. Many of the loci representing ancestral clusters, which are believed to contribute to enteric survival and pathogenesis, are present in strain 105.5R(r) but lost in strain 8081. Insertion elements in 105.5R(r) have a pattern distinct from those in strain 8081 and were exclusively located in a strain-specific region. In summary, our comparative genome analysis indicates that these two strains may have attained their pathogenicity by completely separate evolutionary events, and the 105.5R(r) strain, a representative of the Old World biogroup, lies in a branch of Y. enterocolitica that is distinct from the “New World” 8081 strain. PMID:21325549

Selective epitaxial growth properties and strain characterization of Si1- x Ge x in SiO2 trench arrays

NASA Astrophysics Data System (ADS)

Koo, Sangmo; Jang, Hyunchul; Ko, Dae-Hong

2017-04-01

In this study, we investigated the formation of a Si1- x Ge x fin structure in SiO2 trench arrays via an ultra-high-vacuum chemical-vapor deposition (UHV-CVD) selective epitaxial growth (SEG) process. Defect generation and microstructures of Si1- x Ge x fin structures with different Ge concentrations ( x = 0.2, 0.3 and 0.45) were examined. In addition, the strain evolution of a Si1- x Ge x fin structure was analyzed by using reciprocal space mapping (RSM). An (111) facet was formed from the Si1- x Ge x epi-layer and SiO2 trench wall interface to minimize the interface and the surface energy. The Si1- x Ge x fin structures were fully relaxed along the direction perpendicular to the trenches regardless of the Ge concentration. On the other hand, the fin structures were fully or partially strained along the direction parallel to the trenches depending on the Ge concentration: fully strained Si0.8Ge0.2 and Si0.7Ge0.3, and a Si0.55Ge0.45 strain-relaxed buffer. We further confirmed that the strain on the Si1- x Ge x fin structures remained stable after oxide removal and H2/N2 post-annealing.

Revealing the core-shell interactions of a giant strain relaxor ferroelectric 0.75Bi1/2Na1/2TiO3-0.25SrTiO3.

PubMed

Liu, Na; Acosta, Matias; Wang, Shuai; Xu, Bai-Xiang; Stark, Robert W; Dietz, Christian

2016-11-14

Lead-free relaxor ferroelectrics that feature a core-shell microstructure provide an excellent electromechanical response. They even have the potential to replace the environmentally hazardous lead-zirconia-titanate (PZT) in large strain actuation applications. Although the dielectric properties of core-shell ceramics have been extensively investigated, their piezoelectric properties are not yet well understood. To unravel the interfacial core-shell interaction, we studied the relaxation behaviour of field-induced ferroelectric domains in 0.75Bi 1/2 Na 1/2 TiO 3 -0.25SrTiO 3 (BNT-25ST), as a typical core-shell bulk material, using a piezoresponse force microscope. We found that after poling, lateral domains emerged at the core-shell interface and propagated to the shell region. Phase field simulations showed that the increased electrical potential beneath the core is responsible for the in-plane domain evolution. Our results imply that the field-induced domains act as pivotal points at the coherent heterophase core-shell interface, reinforcing the phase transition in the non-polar shell and thus promoting the giant strain.

4-O-(1-carboxyethyl)-D-galactose. A new acidic sugar from the extracellular polysaccharide produced by Butyrivibrio fibrisolvens strain 49.

PubMed Central

Stack, R J; Stein, T M; Plattner, R D

1988-01-01

The structure of a new acidic sugar from the extracellular polysaccharide of Butyrivibrio fibrisolvens strain 49 was determined as 4-O-(1-carboxyethyl)-D-galactose on the basis of 13C-n.m.r. and 1H-n.m.r. spectroscopy, m.s. and chemical degradation studies. PMID:3223950

ArgO145, a Stx2a prophage of a bovine O145:H- STEC strain, is closely related to phages of virulent human strains.

PubMed

Krüger, A; Burgán, J; Friedrich, A W; Rossen, J W A; Lucchesi, P M A

2018-06-01

Shiga toxins (Stx) are the main virulence factor of a pathogroup of Escherichia coli strains that cause severe human diseases. These toxins are encoded in prophages (Stx prophages), and generally their expression depends on prophage induction. Several studies have reported high diversity among both Stx prophages and Stx. In particular, the toxin subtype Stx2a is associated with high virulence and HUS. Here, we report the genome of ArgO145, an inducible Stx2a prophage identified in a bovine O145:H- strain which produced high levels of Shiga toxin and Stx phage particles. The ArgO145 genome shared lambda phage organization, with recombination, regulation, replication, lysis, and head and tail structural gene regions, although some lambda genes encoding regulatory proteins could not be identified. Remarkably, some Stx2a phages of strains isolated from patients in other countries showed high similarity to ArgO145. Copyright © 2018 Elsevier B.V. All rights reserved.

Magnetic Orders of LaTiO3 and YTiO3 Under Epitaxial Strain: a First-Principles study

NASA Astrophysics Data System (ADS)

Weng, Yakui; Huang, Xin; Tang, Yankun; Dong, Shuai

2014-03-01

Perovskite RTiO3 family is a typical Mott-insulator with localized 3d electrons. In this work, the epitaxial strain effects on the ground magnetic orders of LaTiO3 and YTiO3 films have been studied using the first-principles density-functional theory. For the YTiO3 films, A-type antiferromagnetic order emerges against the original ferromagnetic order under the in-plane compressive strain by LaAlO3 (001) substrate, although the A-type antiferromagnetic order does not exist in any RTiO3 bulks. Then, for the LaTiO3 films under the compressive strain, e.g. LaTiO3 films grown on LaAlO3, LaGaO3, and SrTiO3 substrates, undergo a phase transition from the original G-type antiferromagnetism to A-type antiferromagnetism. While under the tensile strain, e.g. grown on the BaTiO3 and LaScO3 substrate, LaTiO3 films show a tendency to transit to the C-type antiferromagnetism. Furthermore, our calculations find that the magnetic transitions under epitaxial strain do not change the insulating fact of LaTiO3 and YTiO3.

Giant strain control of magnetoelectric effect in Ta|Fe|MgO

PubMed Central

Odkhuu, Dorj

2016-01-01

The exploration of electric field controlled magnetism has come under scrutiny for its intriguing magnetoelectric phenomenon as well as technological advances in spintronics. Herein, the tremendous effect of an epitaxial strain on voltage-controlled perpendicular magnetic anisotropy (VPMA) is demonstrated in a transition-metal|ferromagnet|MgO (TM|FM|MgO) heterostructure from first-principles electronic structure computation. By tuning the epitaxial strain in Ta|Fe|MgO as a model system of TM|FM|MgO, we find distinctly different behaviours of VPMA from V- to Λ-shape trends with a substantially large magnetoelectric coefficient, up to an order of 103 fJV−1m−1. We further reveal that the VPMA modulation under strain is mainly governed by the inherently large spin-orbit coupling of Ta 5d–Fe 3d hybridized orbitals at the TM|FM interface, although the Fe 3d–O 2p hybridization at the FM|MgO interface is partly responsible in determining the PMA of Ta|Fe|MgO. These results suggest that the control of epitaxial strain enables the engineering of VPMA, and provides physical insights for the divergent behaviors of VPMA and magnetoelectric coefficients found in TM|FM|MgO experiments. PMID:27597448

Magnetic orders of LaTiO3 under epitaxial strain: A first-principles study

NASA Astrophysics Data System (ADS)

Weng, Yakui; Huang, Xin; Tang, Yankun; Dong, Shuai

2014-05-01

Perovskite LaTiO3 bulk is a typical Mott-insulator with G-type antiferromagnetic order. In this work, the biaxial strain effects on the ground magnetic order of LaTiO3 films grown on various substrates have been studied. For the compressive strain, LaTiO3 films grown on LaAlO3, LaGaO3, and SrTiO3 substrates undergo a phase transition from the original G-type antiferromagnet to A-type antiferromagnet. The underlying physical mechanisms are the lattice distortions tunned by strain. While for the tensile strain, the BaTiO3 and LaScO3 substrates have been tested, which show a tendency to transit the LaTiO3 to the C-type antiferromagnet. Furthermore, our calculations find that the magnetic transitions under epitaxial strain do not change the insulating fact of LaTiO3.

Strain-induced nanostructure of Pb(Mg1/3Nb2/3)O3-PbTiO3 on SrTiO3 epitaxial thin films with low PbTiO3 concentration

NASA Astrophysics Data System (ADS)

Kiguchi, Takanori; Fan, Cangyu; Shiraishi, Takahisa; Konno, Toyohiko J.

2017-10-01

The singularity of the structure in (1 - x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-xPT) (x = 0-50 mol %) epitaxial thin films of 100 nm thickness was investigated from the viewpoint of the localized residual strain in the nanoscale. The films were deposited on SrTiO3 (STO) (001) single-crystal substrates by chemical solution deposition (CSD) using metallo-organic decomposition (MOD) solutions. X-ray and electron diffraction patterns revealed that PMN-xPT thin films included a single phase of the perovskite-type structure with the cube-on-cube orientation relationship between PMN-xPT and STO: (001)Film ∥ (001)Sub, [100]Film ∥ [100]Sub. X-ray reciprocal space maps showed an in-plane tensile strain in all the compositional ranges considered. Unit cells in the films were strained from the rhombohedral (pseudocubic) (R) phase to a lower symmetry crystal system, the monoclinic (MB) phase. The morphotropic phase boundary (MPB) that split the R and tetragonal (T) phases was observed at x = 30-35 for bulk crystals of PMN-xPT, whereas the strain suppressed the transformation from the R phase to the T phase in the films up to x = 50. High-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM) analysis and its related local strain analysis revealed that all of the films have a bilayer morphology. The nanoscale strained layer formed only above the film/substrate semi-coherent interface. The misfit dislocations generated the localized and periodic strain fields deformed the unit cells between the dislocation cores from the R to an another type of the monoclinic (MA) phase. Thus, the singular and localized residual strains in the PMN-xPT/STO (001) epitaxial thin films affect the phase stability around the MPB composition and result in the MPB shift phenomena.

The Escherichia coli Serogroup O1 and O2 Lipopolysaccharides Are Encoded by Multiple O-antigen Gene Clusters.

PubMed

Delannoy, Sabine; Beutin, Lothar; Mariani-Kurkdjian, Patricia; Fleiss, Aubin; Bonacorsi, Stéphane; Fach, Patrick

2017-01-01

Escherichia coli strains belonging to serogroups O1 and O2 are frequently associated with human infections, especially extra-intestinal infections such as bloodstream infections or urinary tract infections. These strains can be associated with a large array of flagellar antigens. Because of their frequency and clinical importance, a reliable detection of E. coli O1 and O2 strains and also the frequently associated K1 capsule is important for diagnosis and source attribution of E. coli infections in humans and animals. By sequencing the O-antigen clusters of various O1 and O2 strains we showed that the serogroups O1 and O2 are encoded by different sets of O-antigen encoding genes and identified potentially new O-groups. We developed qPCR-assays to detect the various O1 and O2 variants and the K1-encoding gene. These qPCR assays proved to be 100% sensitive and 100% specific and could be valuable tools for the investigations of zoonotic and food-borne infection of humans with O1 and O2 extra-intestinal (ExPEC) or Shiga toxin-producing E. coli (STEC) strains.

The Escherichia coli Serogroup O1 and O2 Lipopolysaccharides Are Encoded by Multiple O-antigen Gene Clusters

PubMed Central

Delannoy, Sabine; Beutin, Lothar; Mariani-Kurkdjian, Patricia; Fleiss, Aubin; Bonacorsi, Stéphane; Fach, Patrick

2017-01-01

Escherichia coli strains belonging to serogroups O1 and O2 are frequently associated with human infections, especially extra-intestinal infections such as bloodstream infections or urinary tract infections. These strains can be associated with a large array of flagellar antigens. Because of their frequency and clinical importance, a reliable detection of E. coli O1 and O2 strains and also the frequently associated K1 capsule is important for diagnosis and source attribution of E. coli infections in humans and animals. By sequencing the O-antigen clusters of various O1 and O2 strains we showed that the serogroups O1 and O2 are encoded by different sets of O-antigen encoding genes and identified potentially new O-groups. We developed qPCR-assays to detect the various O1 and O2 variants and the K1-encoding gene. These qPCR assays proved to be 100% sensitive and 100% specific and could be valuable tools for the investigations of zoonotic and food-borne infection of humans with O1 and O2 extra-intestinal (ExPEC) or Shiga toxin-producing E. coli (STEC) strains. PMID:28224115

A Filamentous Phage Associated with Recent Pandemic Vibrio parahaemolyticus O3:K6 Strains

PubMed Central

Nasu, Hatsumi; Iida, Tetsuya; Sugahara, Tomomi; Yamaichi, Yoshiharu; Park, Kwon-Sam; Yokoyama, Katsushi; Makino, Kozo; Shinagawa, Hideo; Honda, Takeshi

2000-01-01

A specific serotype, O3:K6, of Vibrio parahaemolyticus has recently been causing epidemics of gastroenteritis in Southeast Asia, Japan, and North America. To examine whether the new O3:K6 strains possess characteristics that may exacerbate outbreaks, we compared V. parahaemolyticus O3:K6 strains with non-O3:K6 strains using strains isolated from individuals with traveler's diarrhea at Kansai Airport Quarantine Station, Osaka, Japan. All 24 O3:K6 strains possessed a common plasmid, pO3K6 (DNA size, 8,782 bp, with 10 open reading frames [ORFs]). The gene organization of pO3K6 was similar to that of Vf33, a filamentous phage previously described in V. parahaemolyticus. We isolated a phage (phage f237) from the culture supernatant of V. parahaemolyticus O3:K6 strain KXV237, which formed a turbid plaque on an indicator strain. The genome of f237 was single-stranded DNA, and the double-stranded DNA obtained by treatment of the genome with DNA polymerase was identical to that of pO3K6 when analyzed by agarose gel electrophoresis after HindIII digestion. Furthermore, the N-terminal amino acid sequence of the f237 major coat protein was found in ORF4 of pO3K6. Our results showed that pO3K6 is a replicative form of f237. Among the ORFs found in the f237 genome, the sequence of ORF8 had no significant homology to those of any proteins in databases. ORF8 was located on a region corresponding to the distinctive region of Vf33, and its G+C content was apparently lower than that of the remaining DNA sequence of f237. By colony hybridization, ORF8 was detected only in O3:K6 strains isolated since 1996 and was not found in O3:K6 strains isolated before 1996 and clinical V. parahaemolyticus strains other than those of serotype O3:K6. Thus, this study shows that f237 is exclusively associated with recent V. parahaemolyticus O3:K6 strains. The ORF8 gene can be a useful genetic marker for the identification of the recently widespread O3:K6 strains of V. parahaemolyticus. PMID:10834969

Development of a multiplex PCR-based rapid typing method for enterohemorrhagic Escherichia coli O157 strains.

PubMed

Ooka, Tadasuke; Terajima, Jun; Kusumoto, Masahiro; Iguchi, Atsushi; Kurokawa, Ken; Ogura, Yoshitoshi; Asadulghani, Md; Nakayama, Keisuke; Murase, Kazunori; Ohnishi, Makoto; Iyoda, Sunao; Watanabe, Haruo; Hayashi, Tetsuya

2009-09-01

Enterohemorrhagic Escherichia coli O157 (EHEC O157) is a food-borne pathogen that has raised worldwide public health concern. The development of simple and rapid strain-typing methods is crucial for the rapid detection and surveillance of EHEC O157 outbreaks. In the present study, we developed a multiplex PCR-based strain-typing method for EHEC O157, which is based on the variability in genomic location of IS629 among EHEC O157 strains. This method is very simple, in that the procedures are completed within 2 h, the analysis can be performed without the need for special equipment or techniques (requiring only conventional PCR and agarose gel electrophoresis systems), the results can easily be transformed into digital data, and the genes for the major virulence markers of EHEC O157 (the stx(1), stx(2), and eae genes) can be detected simultaneously. Using this method, 201 EHEC O157 strains showing different XbaI digestion patterns in pulsed-field gel electrophoresis (PFGE) analysis were classified into 127 types, and outbreak-related strains showed identical or highly similar banding patterns. Although this method is less discriminatory than PFGE, it may be useful as a primary screening tool for EHEC O157 outbreaks.

48 CFR 1552.216-75 - Base fee and award fee proposal.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 48 Federal Acquisition Regulations System 6 2013-10-01 2013-10-01 false Base fee and award fee... 1552.216-75 Base fee and award fee proposal. As prescribed in 1516.405(b), insert the following clause: Base Fee and Award Fee Proposal (FEB 1999) For the purpose of this solicitation, offerors shall propose...

48 CFR 1552.216-75 - Base fee and award fee proposal.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 48 Federal Acquisition Regulations System 6 2012-10-01 2012-10-01 false Base fee and award fee... 1552.216-75 Base fee and award fee proposal. As prescribed in 1516.405(b), insert the following clause: Base Fee and Award Fee Proposal (FEB 1999) For the purpose of this solicitation, offerors shall propose...

48 CFR 1552.216-75 - Base fee and award fee proposal.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Base fee and award fee... 1552.216-75 Base fee and award fee proposal. As prescribed in 1516.405(b), insert the following clause: Base Fee and Award Fee Proposal (FEB 1999) For the purpose of this solicitation, offerors shall propose...

48 CFR 1552.235-70 - Screening business information for claims of confidentiality.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Screening business... Texts of Provisions and Clauses 1552.235-70 Screening business information for claims of confidentiality... proprietary or confidential by the business that has the right to the information. The following clause...

Specific Detection of Enteroaggregative Hemorrhagic Escherichia coli O104:H4 Strains by Use of the CRISPR Locus as a Target for a Diagnostic Real-Time PCR

PubMed Central

Delannoy, Sabine; Beutin, Lothar; Burgos, Ylanna

2012-01-01

In 2011, a large outbreak of an unusual bacterial strain occurred in Europe. This strain was characterized as a hybrid of an enteroaggregative Escherichia coli (EAEC) and a Shiga toxin-producing E. coli (STEC) strain of the serotype O104:H4. Here, we present a single PCR targeting the clustered regularly interspaced short palindromic repeats locus of E. coli O104:H4 (CRISPRO104:H4) for specific detection of EAEC STEC O104:H4 strains from different geographical locations and time periods. The specificity of the CRISPRO104:H4 PCR was investigated using 1,321 E. coli strains, including reference strains for E. coli O serogroups O1 to O186 and flagellar (H) types H1 to H56. The assay was compared for specificity using PCR assays targeting different O104 antigen-encoding genes (wbwCO104, wzxO104, and wzyO104). The PCR assays reacted with all types of E. coli O104 strains (O104:H2, O104:H4, O104:H7, and O104:H21) and with E. coli O8 and O9 strains carrying the K9 capsular antigen and were therefore not specific for detection of the EAEC STEC O104:H4 type. A single PCR developed for the CRISPRO104:H4 target was sufficient for specific identification and detection of the 48 tested EAEC STEC O104:H4 strains. The 35 E. coli O104 strains expressing H types other than H4 as well as 8 E. coli strains carrying a K9 capsular antigen tested all negative for the CRISPRO104:H4 locus. Only 12 (0.94%) of the 1,273 non-O104:H4 E. coli strains (serotypes Ont:H2, O43:H2, O141:H2, and O174:H2) reacted positive in the CRISPRO104:H4 PCR (99.06% specificity). PMID:22895033

Denitrifying metabolism of the methylotrophic marine bacterium Methylophaga nitratireducenticrescens strain JAM1.

PubMed

Mauffrey, Florian; Cucaita, Alexandra; Constant, Philippe; Villemur, Richard

2017-01-01

Methylophaga nitratireducenticrescens strain JAM1 is a methylotrophic, marine bacterium that was isolated from a denitrification reactor treating a closed-circuit seawater aquarium. It can sustain growth under anoxic conditions by reducing nitrate ([Formula: see text]) to nitrite ([Formula: see text]). These physiological traits are attributed to gene clusters that encode two dissimilatory nitrate reductases (Nar). Strain JAM1 also contains gene clusters encoding two nitric oxide (NO) reductases and one nitrous oxide (N 2 O) reductase, suggesting that NO and N 2 O can be reduced by strain JAM1. Here we characterized further the denitrifying activities of M. nitratireducenticrescens JAM1. Series of oxic and anoxic cultures of strain JAM1 were performed with N 2 O, [Formula: see text] or sodium nitroprusside, and growth and N 2 O, [Formula: see text], [Formula: see text] and N 2 concentrations were measured. Ammonium ([Formula: see text])-free cultures were also tested to assess the dynamics of N 2 O, [Formula: see text] and [Formula: see text]. Isotopic labeling of N 2 O was performed in 15 NH 4 + -amended cultures. Cultures with the JAM1Δ narG1narG2 double mutant were performed to assess the involvement of the Nar systems on N 2 O production. Finally, RT-qPCR was used to measure the gene expression levels of the denitrification genes cytochrome bc -type nitric oxide reductase ( cnorB1 and cnorB2 ) and nitrous oxide reductase ( nosZ ), and also nnrS and norR that encode NO-sensitive regulators. Strain JAM1 can reduce NO to N 2 O and N 2 O to N 2 and can sustain growth under anoxic conditions by reducing N 2 O as the sole electron acceptor. Although strain JAM1 lacks a gene encoding a dissimilatory [Formula: see text] reductase, [Formula: see text]-amended cultures produce N 2 O, representing up to 6% of the N-input. [Formula: see text] was shown to be the key intermediate of this production process. Upregulation in the expression of c norB1 , cnorB2, nnrS and nor

Clonal origins of Vibrio cholerae O1 El Tor strains, Papua New Guinea, 2009-2011.

PubMed

Horwood, Paul F; Collins, Deirdre; Jonduo, Marinjho H; Rosewell, Alexander; Dutta, Samir R; Dagina, Rosheila; Ropa, Berry; Siba, Peter M; Greenhill, Andrew R

2011-11-01

We used multilocus sequence typing and variable number tandem repeat analysis to determine the clonal origins of Vibrio cholerae O1 El Tor strains from an outbreak of cholera that began in 2009 in Papua New Guinea. The epidemic is ongoing, and transmission risk is elevated within the Pacific region.

Strain dependence of interfacial antiferromagnetic coupling in La0.7Sr0.3MnO3/SrRuO3 superlattices

NASA Astrophysics Data System (ADS)

Das, Sujit; Herklotz, Andreas; Pippel, Eckhard; Guo, Er-Jia; Rata, Diana; Dörr, Kathrin

2015-03-01

We have investigated the magnetic response of La0.7Sr0.3MnO3/SrRuO3 superlattices to biaxial in-plane strain applied in-situ. Superlattices grown on piezoelectric substrates of 0.72PbMg1/3Nb2/3O3-0.28PbTiO3(001) (PMN-PT) show strong antiferromagnetic coupling of the two ferromagnetic components. The coupling field of μ0HAF = 1.8 T is found to change by μ0 ΔHAF / Δɛ ~ -520 mT %-1 under reversible biaxial strain (Δɛ) at 80 K in a [La0.7Sr0.3MnO3(22 Å)/SrRuO3(55 Å)]15 superlattice. This reveals a significant strain effect on interfacial coupling. The applied in-plane compression enhances the ferromagnetic order in the manganite layers which are under as-grown tensile strain. It is thus difficult to disentangle the contributions from strain-dependent antiferromagnetic Mn-O-Ru interface coupling and Mn-O-Mn ferromagnetic double exchange near the interface, since the enhanced magnetic order of Mn spins leads to a larger net coupling of SrRuO3 layers at the interface. We discuss our experimental findings taken into account both the strain-dependent orbital occupation in a single-ion picture and the enhanced Mn order at the interface. This work was supported by the DFG within the Collaborative Research Center SFB 762 ``Functionality of Oxide Interfaces.''

Comparative genome analysis of non-toxigenic non-O1 versus toxigenic O1 Vibrio cholerae

PubMed Central

Mukherjee, Munmun; Kakarla, Prathusha; Kumar, Sanath; Gonzalez, Esmeralda; Floyd, Jared T.; Inupakutika, Madhuri; Devireddy, Amith Reddy; Tirrell, Selena R.; Bruns, Merissa; He, Guixin; Lindquist, Ingrid E.; Sundararajan, Anitha; Schilkey, Faye D.; Mudge, Joann; Varela, Manuel F.

2015-01-01

Pathogenic strains of Vibrio cholerae are responsible for endemic and pandemic outbreaks of the disease cholera. The complete toxigenic mechanisms underlying virulence in Vibrio strains are poorly understood. The hypothesis of this work was that virulent versus non-virulent strains of V. cholerae harbor distinctive genomic elements that encode virulence. The purpose of this study was to elucidate genomic differences between the O1 serotypes and non-O1 V. cholerae PS15, a non-toxigenic strain, in order to identify novel genes potentially responsible for virulence. In this study, we compared the whole genome of the non-O1 PS15 strain to the whole genomes of toxigenic serotypes at the phylogenetic level, and found that the PS15 genome was distantly related to those of toxigenic V. cholerae. Thus we focused on a detailed gene comparison between PS15 and the distantly related O1 V. cholerae N16961. Based on sequence alignment we tentatively assigned chromosome numbers 1 and 2 to elements within the genome of non-O1 V. cholerae PS15. Further, we found that PS15 and O1 V. cholerae N16961 shared 98% identity and 766 genes, but of the genes present in N16961 that were missing in the non-O1 V. cholerae PS15 genome, 56 were predicted to encode not only for virulence–related genes (colonization, antimicrobial resistance, and regulation of persister cells) but also genes involved in the metabolic biosynthesis of lipids, nucleosides and sulfur compounds. Additionally, we found 113 genes unique to PS15 that were predicted to encode other properties related to virulence, disease, defense, membrane transport, and DNA metabolism. Here, we identified distinctive and novel genomic elements between O1 and non-O1 V. cholerae genomes as potential virulence factors and, thus, targets for future therapeutics. Modulation of such novel targets may eventually enhance eradication efforts of endemic and pandemic disease cholera in afflicted nations. PMID:25722857

Comparative genome analysis of non-toxigenic non-O1 versus toxigenic O1 Vibrio cholerae.

PubMed

Mukherjee, Munmun; Kakarla, Prathusha; Kumar, Sanath; Gonzalez, Esmeralda; Floyd, Jared T; Inupakutika, Madhuri; Devireddy, Amith Reddy; Tirrell, Selena R; Bruns, Merissa; He, Guixin; Lindquist, Ingrid E; Sundararajan, Anitha; Schilkey, Faye D; Mudge, Joann; Varela, Manuel F

Pathogenic strains of Vibrio cholerae are responsible for endemic and pandemic outbreaks of the disease cholera. The complete toxigenic mechanisms underlying virulence in Vibrio strains are poorly understood. The hypothesis of this work was that virulent versus non-virulent strains of V. cholerae harbor distinctive genomic elements that encode virulence. The purpose of this study was to elucidate genomic differences between the O1 serotypes and non-O1 V. cholerae PS15, a non-toxigenic strain, in order to identify novel genes potentially responsible for virulence. In this study, we compared the whole genome of the non-O1 PS15 strain to the whole genomes of toxigenic serotypes at the phylogenetic level, and found that the PS15 genome was distantly related to those of toxigenic V. cholerae . Thus we focused on a detailed gene comparison between PS15 and the distantly related O1 V. cholerae N16961. Based on sequence alignment we tentatively assigned chromosome numbers 1 and 2 to elements within the genome of non-O1 V. cholerae PS15. Further, we found that PS15 and O1 V. cholerae N16961 shared 98% identity and 766 genes, but of the genes present in N16961 that were missing in the non-O1 V. cholerae PS15 genome, 56 were predicted to encode not only for virulence-related genes (colonization, antimicrobial resistance, and regulation of persister cells) but also genes involved in the metabolic biosynthesis of lipids, nucleosides and sulfur compounds. Additionally, we found 113 genes unique to PS15 that were predicted to encode other properties related to virulence, disease, defense, membrane transport, and DNA metabolism. Here, we identified distinctive and novel genomic elements between O1 and non-O1 V. cholerae genomes as potential virulence factors and, thus, targets for future therapeutics. Modulation of such novel targets may eventually enhance eradication efforts of endemic and pandemic disease cholera in afflicted nations.

Structural analysis of O-polysaccharide chains extracted from different Salmonella Typhimurium strains.

PubMed

Micoli, Francesca; Ravenscroft, Neil; Cescutti, Paola; Stefanetti, Giuseppe; Londero, Silvia; Rondini, Simona; Maclennan, Calman A

2014-02-19

Salmonella Typhimurium is the major cause of invasive nontyphoidal Salmonella disease in Africa, with high mortality among children and HIV-infected individuals. Currently, no vaccine is available for use in humans. Antibodies directed against the O-polysaccharide of the lipopolysaccharide molecule of Salmonella mediate bacterial killing and are protective, and conjugation of the O-polysaccharide to a carrier protein represents a possible strategy for vaccine development. Here we have purified the O-polysaccharide from six different strains of S. Typhimurium and fully characterized them using analytical methods including HPLC-SEC, HPAEC-PAD, GC, GC-MS, 1D and 2D NMR spectroscopy. All the O-polysaccharide samples showed a similar bimodal molecular mass distribution, but differed with respect to the amount and position of O-acetylation and glucosylation. For some strains, O-acetyl groups were found not only on C-2 of abequose (factor 5 specificity), but also on C-2 and C-3 of rhamnose; glucose was found to be linked 1→4 or 1→6 to galactose in different amounts according to the strain of origin. This structural variability could have an impact on the immunogenicity of corresponding glycoconjugate vaccines and different strains need to be evaluated in order to identify the appropriate source of O-polysaccharide to use for the development of a candidate conjugate vaccine with broad coverage against S. Typhimurium. Copyright © 2013 Elsevier Ltd. All rights reserved.

Strain dependence of antiferromagnetic interface coupling in La 0.7Sr 0.3MnO 3/SrRuO 3 superlattices

DOE PAGES

Das, Sujit; Herklotz, Andreas; Pippel, Eckhard; ...

2015-04-06

We have investigated the magnetic response of La 0.7Sr 0.3MnO 3/SrRuO 3 superlattices to biaxial in-plane strain applied in situ. Superlattices grown on piezoelectric substrates of 0.72PbMg 1/3Nb 2/3O 3-0.28PbTiO 3(001) (PMN-PT) show strong antiferromagnetic coupling of the two ferromagnetic components. The coupling field of mu H-0(AF) = 1.8 T is found to change by mu(0)Delta H-AF/Delta epsilon similar to -520 mT %(-1) under reversible biaxial strain Delta epsilon at 80 K in a [La 0.7Sr 0.3MnO 3(22 angstrom)/SrRuO 3(55 angstrom)] 15 superlattice. This reveals a significant strain effect on interfacial coupling. The applied in-plane compression enhances the ferromagnetic ordermore » in the manganite layers, which are under as-grown tensile strain, leading to a larger net coupling of SrRuO 3 layers at the interface. It is thus difficult to disentangle the contributions from strain-dependent antiferromagnetic Mn-O-Ru interface coupling and Mn-O-Mn ferromagnetic double exchange near the interface for the strength of the apparent antiferromagnetic coupling. We discuss our results in the framework of available models.« less

Enhancing the humidity sensitivity of Ga2O3 /SnO2 core/shell microribbon by applying mechanical strain and its application as a flexible strain sensor.

PubMed

Liu, Kewei; Sakurai, Makoto; Aono, Masakazu

2012-12-07

The humidity sensitivity of a single β-Ga(2) O(3) /amorphous SnO(2) core/shell microribbon on a flexible substrate is enhanced by the application of tensile strain and increases linearly with the strain. The strain-induced enhancement originates from the increase in the effective surface area where water molecules are adsorbed. This strain dependence of humidity sensitivity can be used to monitor the external strain. The strain sensing of the microribbon device under various amounts of mechanical loading shows excellent reliability and reproducibility with a gauge factor of -41. The flexible device has high potential to detect both humidity and strain at room temperature. These findings and the mechanism involved are expected to pave the way for new flexible strain and multifunctional sensors. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Vibrio cholerae O1 Ogawa Strains Carrying the ctxB7 Allele Caused a Large Cholera Outbreak during 2014 in the Tribal Areas of Odisha, India.

PubMed

Pal, Bibhuti Bhusan; Khuntia, Hemant Kumar; Nayak, Smruti Ranjan; Mohanty, Anima; Biswal, Bhagyalaxmi

2017-09-25

The large outbreak of cholera reported during July to September 2014 in the Narla block of Kalahandi district, India, was investigated to determine the causative organism. Rectal swabs collected from patients with diarrhea and environmental water samples were cultured following standard techniques. The causative organism was identified as Vibrio cholerae O1 Ogawa biotype El Tor, and analysis by double mismatch mutation assay PCR confirmed that all strains were the ctxB7 variant of Haitian V. cholerae O1. The environmental water samples were negative for V. cholerae. The V. cholerae O1 strains were sensitive to tetracycline, ciprofloxacin, norfloxacin, ofloxacin, doxycycline, and azithromycin, but were resistant to erythromycin, gentamicin, chloramphenicol, furazolidone, neomycin, cotrimoxazole, nalidixic acid, and ampicillin. In the 2014 cholera outbreak, the early reporting of the pathogen enabled the government authorities to implement adequate control measures in time to curtail the spread of the disease. That was the second large cholera outbreak due to Haitian variants of V. cholerae O1 after the 2010 Haiti cholera outbreak reported from Odisha, India, and other locations globally. Active surveillance is required to track the spread of this strain in the Odisha region.

Studies on a Novel Serine Protease of a ΔhapAΔprtV Vibrio cholerae O1 Strain and Its Role in Hemorrhagic Response in the Rabbit Ileal Loop Model

PubMed Central

Syngkon, Aurelia; Elluri, Sridhar; Koley, Hemanta; Rompikuntal, Pramod K.; Saha, Dhira Rani; Chakrabarti, Manoj K.; Bhadra, Rupak K.; Wai, Sun Nyunt; Pal, Amit

2010-01-01

Background Two well-characterized proteases secreted by Vibrio cholerae O1 strains are hemagglutinin protease (HAP) and V. cholerae protease (PrtV). The hapA and prtV knock out mutant, V. cholerae O1 strain CHA6.8ΔprtV, still retains residual protease activity. We initiated this study to characterize the protease present in CHA6.8ΔprtV strain and study its role in pathogenesis in rabbit ileal loop model (RIL). Methodology/Principal Findings We partially purified the residual protease secreted by strain CHA6.8ΔprtV from culture supernatant by anion-exchange chromatography. The major protein band in native PAGE was identified by MS peptide mapping and sequence analysis showed homology with a 59-kDa trypsin-like serine protease encoded by VC1649. The protease activity was partially inhibited by 25 mM PMSF and 10 mM EDTA and completely inhibited by EDTA and PMSF together. RIL assay with culture supernatants of strains C6709 (FA ratio 1.1+/−0.3 n = 3), CHA6.8 (FA ratio 1.08+/−0.2 n = 3), CHA6.8ΔprtV (FA ratio 1.02+/−0.2 n = 3) and partially purified serine protease from CHA6.8ΔprtV (FA ratio 1.2+/−0.3 n = 3) induced fluid accumulation and histopathological studies on rabbit ileum showed destruction of the villus structure with hemorrhage in all layers of the mucosa. RIL assay with culture supernatant of CHA6.8ΔprtVΔVC1649 strain (FA ratio 0.11+/−0.005 n = 3) and with protease incubated with PMSF and EDTA (FA ratio 0.3+/−0.05 n = 3) induced a significantly reduced FA ratio with almost complete normal villus structure. Conclusion Our results show the presence of a novel 59-kDa serine protease in a ΔhapAΔprtV V. cholerae O1 strain and its role in hemorrhagic response in RIL model. PMID:20927349

Anethole inhibits growth of recently emerged multidrug resistant toxigenic Vibrio cholerae O1 El Tor variant strains in vitro

PubMed Central

ZAHID, M. Shamim Hasan; AWASTHI, Sharda Prasad; HINENOYA, Atsushi; YAMASAKI, Shinji

2015-01-01

To search natural compounds having inhibitory effect on bacterial growth is important, particularly in view of growing multidrug resistant (MDR) strains of bacterial pathogens. Like other bacterial pathogens, MDR Vibrio cholerae, the causative agent of diarrheal disease cholera, is becoming a great concern. As an approach of searching new antimicrobial agents, here, we show that anethole, a well-studied natural component of sweet fennel and star anise seeds, could potentially inhibit the growth of MDR O1 El Tor biotype, the ongoing 7th cholera pandemic variant strains of toxigenic V. cholerae. The minimum inhibitory concentration (MIC) of anethole against diverse O1 El Tor biotype strains is evaluated as 200 µg/ml. Moreover, the effect of anethole is bactericidal and exerts rapid-killing action on V. cholerae cells. This study is the first report which demonstrates that anethole, purified from natural compound, is a potent inhibitor of growth of toxigenic V. cholerae. Our data suggest that anethole could be a potential antimicrobial drug candidate, particularly against MDR V. cholerae mediated infections. PMID:25648987

Anethole inhibits growth of recently emerged multidrug resistant toxigenic Vibrio cholerae O1 El Tor variant strains in vitro.

PubMed

Zahid, M Shamim Hasan; Awasthi, Sharda Prasad; Hinenoya, Atsushi; Yamasaki, Shinji

2015-05-01

To search natural compounds having inhibitory effect on bacterial growth is important, particularly in view of growing multidrug resistant (MDR) strains of bacterial pathogens. Like other bacterial pathogens, MDR Vibrio cholerae, the causative agent of diarrheal disease cholera, is becoming a great concern. As an approach of searching new antimicrobial agents, here, we show that anethole, a well-studied natural component of sweet fennel and star anise seeds, could potentially inhibit the growth of MDR O1 El Tor biotype, the ongoing 7th cholera pandemic variant strains of toxigenic V. cholerae. The minimum inhibitory concentration (MIC) of anethole against diverse O1 El Tor biotype strains is evaluated as 200 µg/ml. Moreover, the effect of anethole is bactericidal and exerts rapid-killing action on V. cholerae cells. This study is the first report which demonstrates that anethole, purified from natural compound, is a potent inhibitor of growth of toxigenic V. cholerae. Our data suggest that anethole could be a potential antimicrobial drug candidate, particularly against MDR V. cholerae mediated infections.

The Mobilome; A Major Contributor to Escherichia coli stx2-Positive O26:H11 Strains Intra-Serotype Diversity.

PubMed

Delannoy, Sabine; Mariani-Kurkdjian, Patricia; Webb, Hattie E; Bonacorsi, Stephane; Fach, Patrick

2017-01-01

Shiga toxin-producing Escherichia coli of serotype O26:H11/H- constitute a diverse group of strains and several clones with distinct genetic characteristics have been identified and characterized. Whole genome sequencing was performed using Illumina and PacBio technologies on eight stx2 -positive O26:H11 strains circulating in France. Comparative analyses of the whole genome of the stx2 -positive O26:H11 strains indicate that several clones of EHEC O26:H11 are co-circulating in France. Phylogenetic analysis of the French strains together with stx2 -positive and stx -negative E. coli O26:H11 genomes obtained from Genbank indicates the existence of four clonal complexes (SNP-CCs) separated in two distinct lineages, one of which comprises the "new French clone" (SNP-CC1) that appears genetically closely related to stx -negative attaching and effacing E. coli (AEEC) strains. Interestingly, the whole genome SNP (wgSNP) phylogeny is summarized in the cas gene phylogeny, and a simple qPCR assay targeting the CRISPR array specific to SNP-CC1 (SP_O26-E) can distinguish between the two main lineages. The PacBio sequencing allowed a detailed analysis of the mobile genetic elements (MGEs) of the strains. Numerous MGEs were identified in each strain, including a large number of prophages and up to four large plasmids, representing overall 8.7-19.8% of the total genome size. Analysis of the prophage pool of the strains shows a considerable diversity with a complex history of recombination. Each clonal complex (SNP-CC) is characterized by a unique set of plasmids and phages, including stx -prophages, suggesting evolution through separate acquisition events. Overall, the MGEs appear to play a major role in O26:H11 intra-serotype clonal diversification.

The Mobilome; A Major Contributor to Escherichia coli stx2-Positive O26:H11 Strains Intra-Serotype Diversity

PubMed Central

Delannoy, Sabine; Mariani-Kurkdjian, Patricia; Webb, Hattie E.; Bonacorsi, Stephane; Fach, Patrick

2017-01-01

Shiga toxin-producing Escherichia coli of serotype O26:H11/H- constitute a diverse group of strains and several clones with distinct genetic characteristics have been identified and characterized. Whole genome sequencing was performed using Illumina and PacBio technologies on eight stx2-positive O26:H11 strains circulating in France. Comparative analyses of the whole genome of the stx2-positive O26:H11 strains indicate that several clones of EHEC O26:H11 are co-circulating in France. Phylogenetic analysis of the French strains together with stx2-positive and stx-negative E. coli O26:H11 genomes obtained from Genbank indicates the existence of four clonal complexes (SNP-CCs) separated in two distinct lineages, one of which comprises the “new French clone” (SNP-CC1) that appears genetically closely related to stx-negative attaching and effacing E. coli (AEEC) strains. Interestingly, the whole genome SNP (wgSNP) phylogeny is summarized in the cas gene phylogeny, and a simple qPCR assay targeting the CRISPR array specific to SNP-CC1 (SP_O26-E) can distinguish between the two main lineages. The PacBio sequencing allowed a detailed analysis of the mobile genetic elements (MGEs) of the strains. Numerous MGEs were identified in each strain, including a large number of prophages and up to four large plasmids, representing overall 8.7–19.8% of the total genome size. Analysis of the prophage pool of the strains shows a considerable diversity with a complex history of recombination. Each clonal complex (SNP-CC) is characterized by a unique set of plasmids and phages, including stx-prophages, suggesting evolution through separate acquisition events. Overall, the MGEs appear to play a major role in O26:H11 intra-serotype clonal diversification. PMID:28932209

Tensile Lattice Strain Accelerates Oxygen Surface Exchange and Diffusion in La1–xSrxCoO3−δ Thin Films

PubMed Central

2013-01-01

The influence of lattice strain on the oxygen exchange kinetics and diffusion in oxides was investigated on (100) epitaxial La1–xSrxCoO3−δ (LSC) thin films grown by pulsed laser deposition. Planar tensile and compressively strained LSC films were obtained on single-crystalline SrTiO3 and LaAlO3. 18O isotope exchange depth profiling with ToF-SIMS was employed to simultaneously measure the tracer surface exchange coefficient k* and the tracer diffusion coefficient D* in the temperature range 280–475 °C. In accordance with recent theoretical findings, much faster surface exchange (∼4 times) and diffusion (∼10 times) were observed for the tensile strained films compared to the compressively strained films in the entire temperature range. The same strain effect—tensile strain leading to higher k* and D*—was found for different LSC compositions (x = 0.2 and x = 0.4) and for surface-etched films. The temperature dependence of k* and D* is discussed with respect to the contributions of strain states, formation enthalpy of oxygen vacancies, and vacancy mobility at different temperatures. Our findings point toward the control of oxygen surface exchange and diffusion kinetics by means of lattice strain in existing mixed conducting oxides for energy conversion applications. PMID:23527691

40 CFR 180.1289 - Candida oleophila Strain O; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Candida oleophila Strain O; exemption... FOOD Exemptions From Tolerances § 180.1289 Candida oleophila Strain O; exemption from the requirement... the microbial pesticide, Candida oleophila Strain O, on apples and pears when applied/used as a post...

40 CFR 180.1289 - Candida oleophila Strain O; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 25 2013-07-01 2013-07-01 false Candida oleophila Strain O; exemption... FOOD Exemptions From Tolerances § 180.1289 Candida oleophila Strain O; exemption from the requirement... the microbial pesticide, Candida oleophila Strain O, on apples and pears when applied/used as a post...

40 CFR 180.1289 - Candida oleophila Strain O; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 25 2012-07-01 2012-07-01 false Candida oleophila Strain O; exemption... FOOD Exemptions From Tolerances § 180.1289 Candida oleophila Strain O; exemption from the requirement... the microbial pesticide, Candida oleophila Strain O, on apples and pears when applied/used as a post...

40 CFR 180.1289 - Candida oleophila Strain O; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 24 2014-07-01 2014-07-01 false Candida oleophila Strain O; exemption... FOOD Exemptions From Tolerances § 180.1289 Candida oleophila Strain O; exemption from the requirement... the microbial pesticide, Candida oleophila Strain O, on apples and pears when applied/used as a post...

40 CFR 180.1289 - Candida oleophila Strain O; exemption from the requirement of a tolerance.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 24 2011-07-01 2011-07-01 false Candida oleophila Strain O; exemption... FOOD Exemptions From Tolerances § 180.1289 Candida oleophila Strain O; exemption from the requirement... the microbial pesticide, Candida oleophila Strain O, on apples and pears when applied/used as a post...

Strain induced optical properties of BaReO3

NASA Astrophysics Data System (ADS)

Kumavat, Sandip R.; Kansara, Shivam; Gupta, Sanjeev K.; Sonvane, Yogesh

2018-05-01

Here, we have performed strain induce optical properties of BaReO3 by using density functional theory (DFT). We noticed that after applying intrinsic and extrinsic strain to the BaReO3, it shows the metallic behavior. We also studied optical properties, which show good activity in the ultraviolet region. The results show that after applying intrinsic and extrinsic strain to BaReO3 the absorption peaks are shifted towards the high UV region of the spectrum. Thus, we concluded that, BaReO3 material with extrinsic strain can be useful for high frequency UV device and optoelectronic devices.

Purification and characterization of an oxygen-evolving photosystem II from Leptolyngbya sp. strain O-77.

PubMed

Nakamori, Harutaka; Yatabe, Takeshi; Yoon, Ki-Seok; Ogo, Seiji

2014-08-01

A new cyanobacterium of strain O-77 was isolated from a hot spring at Aso-Kuju National Park, Kumamoto, Japan. According to the phylogenetic analysis determined by 16S rRNA gene sequence, the strain O-77 belongs to the genus Leptolyngbya, classifying into filamentous non-heterocystous cyanobacteria. The strain O-77 showed the thermophilic behavior with optimal growth temperature of 55°C. Moreover, we have purified and characterized the oxygen-evolving photosystem II (PSII) from the strain O-77. The O2-evolving activity of the purified PSII from strain O-77 (PSIIO77) was 1275 ± 255 μmol O2 (mg Chl a)(-1) h(-1). Based on the results of MALDI-TOF mass spectrometry and urea-SDS-PAGE analysis, the purified PSIIO77 was composite of the typical PSII components of CP47, CP43, PsbO, D2, D1, PsbV, PsbQ, PsbU, and several low molecular mass subunits. Visible absorption and 77 K fluorescence spectra of the purified PSIIO77 were almost identical to those of other purified PSIIs from cyanobacteria. This report provides the successful example for the purification and characterization of an active PSII from thermophilic, filamentous non-heterocystous cyanobacteria. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Clonal Origins of Vibrio cholerae O1 El Tor Strains, Papua New Guinea, 2009–2011

PubMed Central

Collins, Deirdre; Jonduo, Marinjho H.; Rosewell, Alexander; Dutta, Samir R.; Dagina, Rosheila; Ropa, Berry; Siba, Peter M.; Greenhill, Andrew R.

2011-01-01

We used multilocus sequence typing and variable number tandem repeat analysis to determine the clonal origins of Vibrio cholerae O1 El Tor strains from an outbreak of cholera that began in 2009 in Papua New Guinea. The epidemic is ongoing, and transmission risk is elevated within the Pacific region. PMID:22099099

High genotypic and phenotypic similarity among Shiga toxin-producing Escherichia coli O111 environmental and outbreak strains.

PubMed

Diodati, Michelle E; Bates, Anne H; Cooley, Michael B; Walker, Samarpita; Mandrell, Robert E; Brandl, Maria T

2015-03-01

Escherichia coli serogroup O111 is among the six most commonly reported non-O157:H7 Shiga toxin-producing E. coli (STEC), which are emerging as important foodborne pathogens. We have assembled a collection of environmental and clinical strains of E. coli O111 from diverse sources and investigated various genotypic and phenotypic characteristics of these strains to gain a better understanding of the epidemiology and biology of this serogroup. Sixty-three percent of the strains (24/38) were of H-type 8, which dominated the environmental- and outbreak-strains group, whereas the sporadic-case strains were more heterogeneous in H-type. All of the environmental and outbreak strains harbored the Shiga toxin 1 gene (stx1), eae, and ehx, and a subset of these also carried the Shiga toxin 2 gene (stx2). Only 9 of 16 sporadic-case strains produced stx1 and/or stx2, and these were mostly of H-type 8 and 10. Pulsed-field gel electrophoresis analysis revealed a cluster of environmental, outbreak, and sporadic illness strains with high phylogenetic similarity. Strains in this pulsogroup were all of the H8 type and STEC pathotype, and carried eae and ehx. Smaller clusters of highly similar STEC O111 strains included outbreak and sporadic illness strains isolated during different time periods or from different geographical locations. A distinct aggregative behavior was observed in the cultures of all environmental and outbreak STEC O111 strains, but not in those of sporadic-case strains. Among environmental and outbreaks strains, aggregation was positively correlated with production of curli fimbriae and RpoS function, and negatively with cellulose synthesis, while the nonaggregative behavior of sporadic-case strains correlated (positively) only with cellulose production. Our results indicate that STEC O111 strains sharing high genotypic similarity and important phenotypic traits with STEC O111 outbreak strains are present in the agricultural environment and may contribute to the

Molecular analyses of Vibrio cholerae O1 clinical strains, including new nontoxigenic variants isolated in Mexico during the Cholera epidemic years between 1991 and 2000.

PubMed

Lizárraga-Partida, Marcial Leonardo; Quilici, Marie-Laure

2009-05-01

We studied the evolution of Vibrio cholerae O1 during the 1991 to 2000 cholera epidemic in Mexico by biochemical, serological, and molecular characterization of strains collected during this period. Strains were divided into toxigenic and nontoxigenic groups according to the presence or absence of genes encoding cholera toxin. As previously reported, we characterized two populations among toxigenic strains, which were present from the first year of the epidemic. BglI rRNA analysis revealed that these strains had ribotype profiles, denoted M5 and M6 in our study, that were identical to those previously designated Koblavi B5 or Popovic 5 and Popovic 6a or Tamayo B21a, respectively. Ribotype M5 was isolated between 1991 and 1993. This ribotype had a low level of genetic variation as detected by pulsed-field gel electrophoresis (PFGE). Ribotype M6 persisted from 1991 to 2000. However, PFGE profiles suggested that two epidemiologically unrelated strains coexisted within this single ribotype from 1995 until the end of the epidemic. We identified three new BglI ribotypes, Mx1, Mx2, and Mx3, from nontoxigenic V. cholerae O1 strains isolated between 1998 and 2000; one of them grouped strains positive for the toxin-coregulated pilus island. They differed from nontoxigenic clones isolated in Latin America and on the U.S. Gulf Coast and are probably autochthonous Mexican V. cholerae O1 variants. Most of these new variants were isolated from states surrounding the Gulf of Mexico, where the highest incidence of cholera in the country was recorded. Thus, the Mexican Gulf Coast, like the U.S. Gulf Coast, may act as an environmental reservoir of V. cholerae O1.

Outbreak of Vibrio cholerae serogroup O1, serotype Ogawa, biotype El Tor strain--La Huasteca Region, Mexico, 2013.

PubMed

Díaz-Quiñonez, Alberto; Hernández-Monroy, Irma; Montes-Colima, Norma; Moreno-Pérez, Asunción; Galicia-Nicolás, Adriana; Martínez-Rojano, Hugo; Carmona-Ramos, Concepción; Sánchez-Mendoza, Miroslava; Rodríguez-Martínez, José Cruz; Suárez-Idueta, Lorena; Jiménez-Corona, María Eugenia; Ruiz-Matus, Cuitláhuac; Kuri-Morales, Pablo

2014-06-27

On September 2 and 6, 2013, Mexico's National System of Epidemiological Surveillance identified two cases of cholera in Mexico City. Rectal swab cultures from both patients were confirmed as toxigenic Vibrio cholerae serogroup O1, serotype Ogawa, biotype El Tor. Pulsed-field gel electrophoresis and virulence gene amplification (ctxA, ctxB, zot, and ace) demonstrated that the strains were identical to one another but different from strains circulating in Mexico previously. The strains were indistinguishable from the strain that has caused outbreaks in Haiti, the Dominican Republic, and Cuba. The strain was susceptible to doxycycline, had intermediate susceptibility to ampicillin and chloramphenicol, was less than fully susceptible to ciprofloxacin, and was resistant to furazolidone and trimethoprim-sulfamethoxazole. An investigation failed to identify a common source of infection, additional cases, or any epidemiologic link between the cases. Both patients were treated with a single, 300-mg dose of doxycycline, and their symptoms resolved.

Remarkable enhancement in thermoelectric performance of BiCuSeO through biaxial strain modulation

NASA Astrophysics Data System (ADS)

Li, Chunhong; Guo, Donglin; Li, Kejian; Shao, Bin; Chen, Dengming; Ma, Yilong; Sun, Jianchun

2018-03-01

We propose to further enhance the thermoelectric performance of BiCuSeO using the biaxial strain. The effect of biaxial strain on the thermoelectric property of BiCuSeO is investigated by using the first-principles calculations combined with the Semiclaasical Boltzmann theory. When the biaxial strain is applied, the Seebeck coefficient is largely enhanced by tensile strain, while the electrical conductivity can be greatly enhanced by compressive strain. The largest zT value of 1.7 at 900 K is then conservatively estimated by using the experimental thermal conductivity, which is 4 times larger than that without biaxial strain. Our results indicate that the biaxial strain could be an effect method to enhance the thermoelectric performance of BiCuSeO.

Antimicrobial effect of 7-O-butylnaringenin, a novel flavonoid, and various natural flavonoids against Helicobacter pylori strains.

PubMed

Moon, Sun Hee; Lee, Jae Hoon; Kim, Kee-Tae; Park, Yong-Sun; Nah, Seung-Yeol; Ahn, Dong Uk; Paik, Hyun-Dong

2013-10-28

The antimicrobial effect of a novel flavonoid (7-O-butylnaringenin) on Helicobacter pylori 26695, 51, and SS1 strains and its inhibitory effect on the urease activity of the strains were evaluated and compared with those of several natural flavonoids. First, various flavonoids were screened for antimicrobial activities using the paper disc diffusion method. Hesperetin and naringenin showed the strongest antimicrobial effects among the natural flavonoids tested, and thus hesperetin and naringenin were selected for comparison with 7-O-butylnaringenin. The antimicrobial effect of 7-O-butylnaringenin was greater than that of the hesperetin and naringenin. H. pylori 51 was more sensitive to 7-O-butylnaringenin (2 log reduction of colony forming units, p < 0.05) than the other two strains at 200 μM. 7-O-Butylnaringenin also showed the highest inhibitory effect against urease activity of H. pylori. Morphological changes of H. pylori 26695 treated with these flavonoids indicated that both hesperetin and 7-O-butylnaringenin at 200 μM damaged the cell membranes.

[Antibiotic resistance pattern of 24, 526 strains of Vibrio cholerae O1 isolated in Mexico from 1991 to 1993].

PubMed

Giono-Cerezo, S; Zárate, A; Gutiérrez, L; Valdespino, J L

1994-01-01

Profile of antimicrobial resistance by Kirby-Bauer method was performed on 24526 Vibrio cholerae O1 strains isolated in México (1991-1993) from fecal swabs in cholera cases and from asymptomatic carriers. Minimal inhibitory concentration (MIC) tests for tetracycline (Te) and doxycycline (D) were done on selected strains. Single antibiotic discs were used at concentrations of: Te, 30 micrograms; D, 30 micrograms; erythromycin (E), 15 micrograms; chloramphenicol (CM), 30 micrograms; ampicillin (AM), 10 micrograms; trimethoprim-sulfamethoxazole (SXT) 1.25 micrograms/23.75 micrograms. Strains whose halos were of a smaller diameter than the intermediate value were considered resistant. It is important to maintain surveillance on antimicrobial susceptibility as epidemiological marker on geographical selected areas in order to detect changes of resistant patterns.

Strain-Induced Ferromagnetism in Antiferromagnetic LuMnO3 Thin Films

NASA Astrophysics Data System (ADS)

White, J. S.; Bator, M.; Hu, Y.; Luetkens, H.; Stahn, J.; Capelli, S.; Das, S.; Döbeli, M.; Lippert, Th.; Malik, V. K.; Martynczuk, J.; Wokaun, A.; Kenzelmann, M.; Niedermayer, Ch.; Schneider, C. W.

2013-07-01

Single phase and strained LuMnO3 thin films are discovered to display coexisting ferromagnetic and antiferromagnetic orders. A large moment ferromagnetism (≈1μB), which is absent in bulk samples, is shown to display a magnetic moment distribution that is peaked at the highly strained substrate-film interface. We further show that the strain-induced ferromagnetism and the antiferromagnetic order are coupled via an exchange field, therefore demonstrating strained rare-earth manganite thin films as promising candidate systems for new multifunctional devices.

The period history of the X-ray pulsar in MSH 15-52

NASA Technical Reports Server (NTRS)

Weisskopf, M. C.; Elsner, R. F.; Darbo, W.; Leahy, D.; Naranan, S.; Harnden, F. R.; Seward, F. D.; Sutherland, P. G.; Grindlay, J. E.

1983-01-01

New and refined mesurements of the pulse period of the X-ray pulsar in the supernova remnant MSH 15-52 are presented. The data were obtained with the Monitor proportional Counter on board the HEAO 2 observatory. The period measurements were obtained by analyzing pulse arrival times determined by cross-correlating sample pulse profiles with a master template. The period history for the source and a representative 0.15 s X-ray light curve are shown. The X-ray measurements alone lead to a refined value of the period derivative of (1.5382 + or -0.0024) x 10 to the -12th s/s, while including the results of more recent radio observations leads to a value of (1.54029 + or -0.00095) x 10 to the -12th s/s. These results indicate a hard-point source surrounded by diffuse nebular emission.

Molecular Analyses of Vibrio cholerae O1 Clinical Strains, Including New Nontoxigenic Variants Isolated in Mexico during the Cholera Epidemic Years between 1991 and 2000▿

PubMed Central

Lizárraga-Partida, Marcial Leonardo; Quilici, Marie-Laure

2009-01-01

We studied the evolution of Vibrio cholerae O1 during the 1991 to 2000 cholera epidemic in Mexico by biochemical, serological, and molecular characterization of strains collected during this period. Strains were divided into toxigenic and nontoxigenic groups according to the presence or absence of genes encoding cholera toxin. As previously reported, we characterized two populations among toxigenic strains, which were present from the first year of the epidemic. BglI rRNA analysis revealed that these strains had ribotype profiles, denoted M5 and M6 in our study, that were identical to those previously designated Koblavi B5 or Popovic 5 and Popovic 6a or Tamayo B21a, respectively. Ribotype M5 was isolated between 1991 and 1993. This ribotype had a low level of genetic variation as detected by pulsed-field gel electrophoresis (PFGE). Ribotype M6 persisted from 1991 to 2000. However, PFGE profiles suggested that two epidemiologically unrelated strains coexisted within this single ribotype from 1995 until the end of the epidemic. We identified three new BglI ribotypes, Mx1, Mx2, and Mx3, from nontoxigenic V. cholerae O1 strains isolated between 1998 and 2000; one of them grouped strains positive for the toxin-coregulated pilus island. They differed from nontoxigenic clones isolated in Latin America and on the U.S. Gulf Coast and are probably autochthonous Mexican V. cholerae O1 variants. Most of these new variants were isolated from states surrounding the Gulf of Mexico, where the highest incidence of cholera in the country was recorded. Thus, the Mexican Gulf Coast, like the U.S. Gulf Coast, may act as an environmental reservoir of V. cholerae O1. PMID:19213700

REPETITIVE SEQUENCE BASED-PCR PROFILING OF ESCHERICHIA COLI O157 STRAINS FROM BEEF IN SOUTHERN THAILAND.

PubMed

Sukhumungoon, Pharanai; Tantadapan, Rujira; Rattanachuay, Pattamarat

2016-01-01

Beef and its products are potential vehicles of Escherichia coli O157, the most important serotype implicated in many large outbreaks of diarrheal infection in humans worldwide. There is a need for rapid detection of contaminated food in order to implement appropriate and effective control measures. In this study, repetitive sequence (rep)-PCR, using three different primers, BOXA1R, ERIC2 and (GTG)5, singly and in combinations, were employed to compare the genetic relatedness among E. coli O157 group with other diarrheagenic E. coli strains as controls. Although a combination of BOXA1R + ERIC2 + (GTG)5 primers generated a rep-PCR profile containing the highest number of amplicon bands among the DEC strains tested, dendrogram (at 80% similarity) exhibited the lowest DEC classification of 5 clusters, whereas that from BOXA1R or BOXA1R+ (GTG)5 rep-PCR profiling produced 8 clusters. Nevertheless, focusing E. coli O157 strains were grouped into 4 clusters irrespective of the rep-PCR profiles analyzed, and all 14 but two, PSU60 and PSU132, E. coli O157 strains isolated from beef in southern Thailand during 2012 to 2014 fell into a single cluster. Thus, rep-PCR profiling generated with BOXA1R or BOXA1R + (GTG)5 is sufficient for distinguishing among DEC strains, including E. coli O157 in southern Thailand.

O-Antigens of Escherichia coli Strains O81 and HS3-104 Are Structurally and Genetically Related, Except O-Antigen Glucosylation in E. coli HS3-104.

PubMed

Zdorovenko, E L; Wang, Y; Shashkov, A S; Chen, T; Ovchinnikova, O G; Liu, B; Golomidova, A K; Babenko, V V; Letarov, A V; Knirel, Y A

2018-05-01

Glycerophosphate-containing O-specific polysaccharides (OPSs) were obtained by mild acidic degradation of lipopolysaccharides isolated from Escherichia coli type strain O81 and E. coli strain HS3-104 from horse feces. The structures of both OPSs and of the oligosaccharide derived from the strain O81 OPS by treatment with 48% HF were studied by monosaccharide analysis and one- and two-dimensional 1H- and 13C-NMR spectroscopy. Both OPSs had similar structures and differed only in the presence of a side-chain glucose residue in the strain HS3-104 OPS. The genes and the organization of the O-antigen biosynthesis gene cluster in both strains are almost identical with the exception of the gtr gene cluster responsible for glucosylations in the strain HS3-104, which is located elsewhere in the genome.

The First Report of Vibrio parahaemolyticus Strain O10:K60 in Japan, a New Combination of O and K Serotypes Isolated from a Patient with Gastroenteritis.

PubMed

Ueno, Hiroyuki; Tomari, Kentaro; Kikuchi, Koji; Kobori, Sumie; Miyazaki, Motonobu

2016-01-01

Vibrio parahaemolyticus is an important pathogen that causes gastroenteritis in humans, generally associated with the consumption of contaminated seafood, particularly raw shellfish. There are many serotypes in V. parahaemolyticus resulting from a combination of O and K antigens. Among them, O3:K6 and their variants, which represent the pandemic clone, are the most widespread strains worldwide. In this study, we examined V. parahaemolyticus isolated from a gastroenteritis patient's stool at a hospital in Saitama City, Japan in 2013. Serotyping of the O and K antigens identified the strain as O10:K60. To our knowledge, this is the first reported case of a V. parahaemolyticus strain with this antigen combination in Japan. Subsequently, we used PCR to assay for pathogenicity-associated genes, and found that it was positive for tdh, T3SS1, and T3SS2α genes. Antibiotic susceptibility tests showed that the strain was susceptible to all selected antibiotics except ampicillin. Moreover, we detected specific marker genes for the pandemic clone with two kinds of PCR assay. Our results suggest that the isolate O10:K60 is a newly emerging serotype that belongs to the pandemic clone.

[Phenotypic and genotypic characterization of Vibrio cholerae O1].

PubMed

Giono-Cerezo, S; Rodríguez Angeles, M G; Gutiérrez-Cogco, L; Valdespino-Gómez, J L

1994-01-01

We made 52180 tests for isolation and identification of toxigenic V. cholerae O1 from rectal swabs and reference strains. We isolated 17.6% V. cholerae O1 strains in 1991, 43.5% in 1992 and 38.9% in 1993. The main serovar in 1991 was Inaba, whereas in 1993 a similar percentage was serovar Ogawa. The phenotype of V. cholerae strains was determined by hemolysis test, Voges-Proskauer test, polymyxin B resistance and phages 4 and 5 resistance. All of the mexican strains were El Tor. There were 2.9-0.75% hemolytic strains from 1991 to 1993, but they were negative when the test was made in tube with human erythrocytes. The resistotypes were performed in 24526 selected strains by Kirby-Bauer method and MIC tests. All of the strains were sensitive, except more than 100 strains isolated in Veracruz that were resistant to tetracycline and doxycycline. Detection of cholera toxin was made by ELISA and on culture of Vero and CHO cells. All the V. cholerae O1 strains were toxigenic. The genotype was determined by PCR and ribotyping. The PCR amplified one 564 pb fragment on V. cholerae O1. The ribotypes of mexican strains were 5 and 6a.

Strain dependence of the electronic properties of LaTiO3 thin films

NASA Astrophysics Data System (ADS)

Moon, S. J.; Kim, Y. S.

2014-11-01

We report on the transport and the core-level X-ray photoemission spectroscopy data of fully-strained LaTiO3 thin films grown on GdScO3 and SrTiO3 substrates. We observed that LaTiO3 thin film grown on GdScO3 showed insulating behavior but that grown on SrTiO3 exhibited a metallic character. We found that while the La 4 d photoemission spectra of the two films were nearly the same, their Ti 2 p and O 1 s data revealed a difference. Our results suggest that strain-induced changes in the Ti-O bonding play an important role in the electronic properties of LaTiO3 thin films.

[Cytotoxic effect of Vibrio cholerae non-O1 on Vero cells].

PubMed

Figueroa-Arredondo, P; García-Lozano, H; Gutiérrez-Cogco, L; Valdespino-Gómez, J L

1994-01-01

At the present time there is still in Mexico a diarrhoeal outbreak due to Vibrio cholerae O1. In INDRE we have isolated from the same outbreak last year (jan-apr), 70 strains of Vibrio cholerae Non-O1. These were isolated from patients with a diarrhoeal illness different from cholera. Patients were of different ages and sex, and from various geographic areas. The isolated strains were confirmed by serological agglutination test with polyclonal antisera, and they neither belong to O1 serogroup or O139. We assayed all the 70 strains in Vero cells, searching for cytotoxic effect, probably attributed to cholera toxin, or any other toxin. The strains were screened by PCR for cholera toxin gene detection, and negative results were obtained. We have found only one CT-producer strain, but it was a rough one so, we are not able to affirm that is not a V. cholerae O1 serotype. Vibrio cholerae Non-O1 strains, tested in Vero cells assay, produced cytotoxic effect within 24 h. It was found that 48/70 strains (66.6%), had cytotoxic activity, showing rounding and then lysis of cells. From our results we concluded that this cytotoxic effect, is not cholera toxin related, instead we propose it could be due to an unknown virulence factor, probably a different toxin in mexican Vibrio cholerae Non-O1 strains.

Antimicrobial Effect of 7-O-Butylnaringenin, a Novel Flavonoid, and Various Natural Flavonoids against Helicobacter pylori Strains

PubMed Central

Moon, Sun Hee; Lee, Jae Hoon; Kim, Kee-Tae; Park, Yong-Sun; Nah, Seung-Yeol; Ahn, Dong Uk; Paik, Hyun-Dong

2013-01-01

The antimicrobial effect of a novel flavonoid (7-O-butylnaringenin) on Helicobacter pylori 26695, 51, and SS1 strains and its inhibitory effect on the urease activity of the strains were evaluated and compared with those of several natural flavonoids. First, various flavonoids were screened for antimicrobial activities using the paper disc diffusion method. Hesperetin and naringenin showed the strongest antimicrobial effects among the natural flavonoids tested, and thus hesperetin and naringenin were selected for comparison with 7-O-butylnaringenin. The antimicrobial effect of 7-O-butylnaringenin was greater than that of the hesperetin and naringenin. H. pylori 51 was more sensitive to 7-O-butylnaringenin (2 log reduction of colony forming units, p < 0.05) than the other two strains at 200 μM. 7-O-Butylnaringenin also showed the highest inhibitory effect against urease activity of H. pylori. Morphological changes of H. pylori 26695 treated with these flavonoids indicated that both hesperetin and 7-O-butylnaringenin at 200 μM damaged the cell membranes. PMID:24169409

EMILiO: a fast algorithm for genome-scale strain design.

PubMed

Yang, Laurence; Cluett, William R; Mahadevan, Radhakrishnan

2011-05-01

Systems-level design of cell metabolism is becoming increasingly important for renewable production of fuels, chemicals, and drugs. Computational models are improving in the accuracy and scope of predictions, but are also growing in complexity. Consequently, efficient and scalable algorithms are increasingly important for strain design. Previous algorithms helped to consolidate the utility of computational modeling in this field. To meet intensifying demands for high-performance strains, both the number and variety of genetic manipulations involved in strain construction are increasing. Existing algorithms have experienced combinatorial increases in computational complexity when applied toward the design of such complex strains. Here, we present EMILiO, a new algorithm that increases the scope of strain design to include reactions with individually optimized fluxes. Unlike existing approaches that would experience an explosion in complexity to solve this problem, we efficiently generated numerous alternate strain designs producing succinate, l-glutamate and l-serine. This was enabled by successive linear programming, a technique new to the area of computational strain design. Copyright © 2011 Elsevier Inc. All rights reserved.

Ferroelectric domain structure of anisotropically strained NaNbO3 epitaxial thin films

NASA Astrophysics Data System (ADS)

Schwarzkopf, J.; Braun, D.; Schmidbauer, M.; Duk, A.; Wördenweber, R.

2014-05-01

NaNbO3 thin films have been grown under anisotropic biaxial strain on several oxide substrates by liquid-delivery spin metalorganic chemical vapor deposition. Compressive lattice strain of different magnitude, induced by the deposition of NaNbO3 films with varying film thickness on NdGaO3 single crystalline substrates, leads to modifications of film orientation and phase symmetry, which are similar to the phase transitions in Pb-containing oxides near the morphotropic phase boundary. Piezoresponse force microscopy measurements exhibit large out-of-plane polarization components, but no distinctive domain structure, while C-V measurements indicate relaxor properties in these films. When tensile strain is provoked by the epitaxial growth on DyScO3, TbScO3, and GdScO3 single crystalline substrates, NaNbO3 films behave rather like a normal ferroelectric. The application of these rare-earth scandate substrates yields well-ordered ferroelectric stripe domains of the type a1/a2 with coherent domain walls aligned along the [001] substrate direction as long as the films are fully strained. With increasing plastic lattice relaxation, initially, a 2D domain pattern with still exclusively in-plane electric polarization, and finally, domains with in-plane and out-of-plane polar components evolve.

Tuning the magnetic properties of LaCoO3 thin films by epitaxial strain

NASA Astrophysics Data System (ADS)

Fuchs, D.; Arac, E.; Pinta, C.; Schuppler, S.; Schneider, R.; v. Löhneysen, H.

2008-01-01

Ferromagnetic order can be induced in LaCoO3 (LCO) thin films by epitaxial strain. Here, we show that the magnetic properties can be “tuned” by epitaxial strain imposed on LCO thin films by the epitaxial growth on various substrate materials, i.e., (001) oriented SrLaAlO4 , LaAlO3 , SrLaGaO4 , (LaAlO3)0.3(Sr2AlTaO6)0.7 , and SrTiO3 . The lattice mismatch at room temperature of the in-plane lattice parameters between the substrate, as , and bulk LCO, ab , ranges from -1.31% to +2.63% . Single-phase, ⟨001⟩ oriented LCO thin films were grown by pulsed laser deposition on all these substrates. Due to the difference of the thermal-expansion coefficients between LCO and the substrates, the films experience an additional tensile strain of about +0.3% during the cooling process after the deposition at Ts=650°C . The film lattice parameters display an elastic behavior, i.e., an increase of the in-plane film lattice parameter with increasing as . From the ratio between the out-of-plane and in-plane strain, we obtain a Poisson ratio of ν≈1/3 . All films show a ferromagnetic transition as determined from magnetization measurements. The magnetization increases strongly with increasing tensile strain, whereas the transition temperature TC after a rapid initial rise appears to saturate at TC≈85K above a=3.86Å . The effective magnetic moment μeff in the paramagnetic state increases almost linearly as a function of the mean lattice parameter ⟨a⟩ , indicating an enhanced population of higher spin states, i.e., intermediate- or high-spin states. The experimental results are discussed in terms of a decrease of the octahedral-site rotation with increasing tensile strain.

Effect of oxygen vacancies and strain on the phonon spectrum of HfO2 thin films

NASA Astrophysics Data System (ADS)

Gao, Lingyuan; Yalon, Eilam; Chew, Annabel R.; Deshmukh, Sanchit; Salleo, Alberto; Pop, Eric; Demkov, Alexander A.

2017-06-01

The effect of strain and oxygen deficiency on the Raman spectrum of monoclinic HfO2 is investigated theoretically using first-principles calculations. 1% in-plane compressive strain applied to a and c axes is found to blue shift the phonon frequencies, while 1% tensile strain does the opposite. The simulations are compared, and good agreement is found with the experimental results of Raman frequencies greater than 110 cm-1 for 50 nm HfO2 thin films. Several Raman modes measured below 110 cm-1 and previously assigned to HfO2 are found to be rotational modes of gases present in air ambient (nitrogen and oxygen). However, localized vibrational modes introduced by threefold-coordinated oxygen (O3) vacancies are identified at 96.4 cm-1 computationally. These results are important for a deeper understanding of vibrational modes in HfO2, which has technological applications in transistors and particularly in resistive random-access memory whose operation relies on oxygen-deficient HfOx.

Thermal tolerance characteristics of non-O157 Shiga toxigenic strains of Escherichia coli (STEC) in a beef broth model system are similar to those of O157:H7 STEC.

PubMed

Vasan, Akhila; Leong, Wan Mei; Ingham, Steve C; Ingham, Barbara H

2013-07-01

The non-O157 Shiga toxigenic Escherichia coli (STEC) serogroups most commonly associated with illness are O26, O45, O103, O111, O121, and O145. In the United States, these serogroups are considered adulterants in raw nonintact beef. To begin to understand the behavior of these pathogens in meat systems, we compared the thermal tolerance of acid-adapted cells of non-O157 STEC and O157:H7 STEC in a beef-derived broth. D58°C-values were determined for at least three strains per serogroup, and D54.6°C-values and D63.6°C-values were determined for one strain per serogroup. Each strain was grown to stationary phase in brain heart infusion broth (BHIB; pH 7.0) and inoculated into prewarmed BHIB in a shaking water bath for thermotolerance experiments at 54.6, 58.0, or 63.6°C (three trials per strain). Samples were heated for up to 160 min at 54.6°C, 3 min at 58.0°C, or 45 s at 63.6°C, with periodic sampling followed by rapid cooling and plating on modified Levine's eosin methylene blue agar. For each strain and temperature, the log CFU per milliliter was plotted versus time, and D-values were determined. Across all strains, the least and most heat tolerant STEC serogroups at 58°C were O145 and O157, respectively. D58°C-values in BHIB ranged from 0.44 min for an O145 strain to 1.42 min for an O157:H7 strain. D58°C-values for O157 STEC strains were significantly higher than those for at least one strain in each of the non-O157 STEC serogroups (P < 0.05) except for serogroup O103. At 54.6°C, the most heat-resistant STEC strain belonged to serogroup O103 and was significantly more heat tolerant than the O157:H7 strains (P < 0.05). Grouping the strains, there were no significant differences in heat tolerance between O157 and non-O157 STEC at 63.6°C (P ≥ 0.05). The z-values for non-O157 STEC strains were comparable to those for O157:H7 STEC strains (P ≥ 0.05), ranging from 4.10 to 5.21°C. These results suggest that thermal processing interventions that target

Three-volt lithium-ion battery with Li[Ni 1/2Mn 3/2]O 4 and the zero-strain insertion material of Li[Li 1/3Ti 5/3]O 4

NASA Astrophysics Data System (ADS)

Ariyoshi, Kingo; Yamamoto, Satoshi; Ohzuku, Tsutomu

A 3 V lithium-ion cell with Li[Ni 1/2Mn 3/2]O 4 ( Fd 3¯m ; a=8.17 Å) and the zero-strain insertion material of Li[Li 1/3Ti 5/3]O 4 ( Fd 3¯m ; a=8.36 Å) was examined with an emphasis on rate-capability and cycle life. This cell showed a quite flat operating voltage of 3.2 V with excellent cycleability. Accelerated cycle tests indicated that 83% of the initial capacity was delivered and stored even after 1100 cycles. Although the calculated energy density of a Li[Li 1/3Ti 5/3]O 4/Li[Ni 1/2Mn 3/2]O 4 cell was about 250 Wh kg -1 or 1000 Wh dm -3 based on the active material weight or volume, the 3 V lithium-ion battery exhibited positive characteristic features, such as flatness in operating voltage, high rate capability, and cycle life.

Genotypes and virulence characteristics of Shiga toxin-producing Escherichia coli O104 strains from different origins and sources.

PubMed

Miko, Angelika; Delannoy, Sabine; Fach, Patrick; Strockbine, Nancy A; Lindstedt, Björn Arne; Mariani-Kurkdjian, Patricia; Reetz, Jochen; Beutin, Lothar

2013-12-01

Sixty-two Escherichia coli strains carrying the wzxO104-gene from different sources, origins and time periods were analyzed for their serotypes, virulence genes and compared for genomic similarity by pulsed-field gel-electrophoresis (PFGE). The O104 antigen was present in 55 strains and the structurally and genetically related capsular antigen K9 in five strains. The presence of 49 genes associated with enteropathogenic E. coli (EPEC), enteroaggregative E. coli (EAEC) and enterohemorrhagic E. coli (EHEC) was investigated. Fifty-four strains of serotypes O104:H2 (n=1), O104:H4 (n=37), O104:H7 (n=5) and O104:H21 (n=11) produced Shiga-toxins (Stx). Among STEC O104, a close association between serotype, virulence gene profile and genomic similarity was found. EAEC virulence genes were only present in STEC O104:H4 strains. EHEC-O157 plasmid-encoded genes were only found in STEC O104:H2, O104:H7 and O104:H21 strains. None of the 62 O104 or K9 strains carried an eae-gene involved in the attaching and effacing phenotype. The 38 O104:H4 strains formed a single PFGE-cluster (>83.7% similarity). Thirty-one of these strains were from the European O104:H4 outbreak in 2011. The outbreak strains and older O104:H4 strains from Germany (2001), Georgia and France (2009) clustered together at>86.2% similarity. O104:H4 strains isolated between 2001 and 2009 differed for some plasmid-encoded virulence genes compared to the outbreak strains from 2011. STEC O104:H21 and STEC O104:H7 strains isolated in the U.S. and in Europe showed characteristic differences in their Stx-types, virulence gene and PFGE profiles indicating that these have evolved separately. E. coli K9 strains were not associated with virulence and were heterogeneous for their serotypes and PFGE profiles. Copyright © 2013 Elsevier GmbH. All rights reserved.

Local strain heterogeneity and elastic relaxation dynamics associated with relaxor behavior in the single-crystal perovskite Pb (I n1 /2N b1 /2 ) O3-PbZr O3-Pb (M g1 /3N b2 /3 ) O3-PbTi O3

NASA Astrophysics Data System (ADS)

He, Wenhui; Carpenter, Michael A.; Lampronti, Giulio I.; Li, Qiang; Yan, Qingfeng

2017-10-01

Recently, Pb (In1/2Nb1/2 ) O3-PbZr O3-Pb (Mg1/3Nb2/3 ) O3-PbTiO3 (PIN-PZ-PMN-PT) relaxor single crystals were demonstrated to possess improved temperature-insensitive properties, which would be desirable for high-power device applications. The relaxor character associated with the development of local random fields (RFs) and a high rhombohedral-tetragonal (R-T) ferroelectric transition temperature (TR-T>120°C) would be critical for the excellent properties. A significant effect of the chemical substitution of In3+ and Zr4+ in PMN-PT to give PIN-PZ-PMN-PT is the development of local strain heterogeneity, which acts to suppress the development of macroscopic shear strains without suppressing the development of local ferroelectric moments and contribute substantially to the RFs in PIN-PZ-PMN-PT. Measurements of elastic and anelastic properties by resonant ultrasound spectroscopy show that PIN-PZ-PMN-PT crystal has a quite different form of elastic anomaly due to Vogel-Fulcher freezing, rather than the a discrete cubic-T transition seen in a single crystal of PMN-28PT. It also has high acoustic loss of the relaxor phase down to TR-T. Analysis of piezoresponse force microscopy phase images at different temperatures provides a quantitative insight into the extent to which the RFs influence the microdomain structure and the short-range order correlation length 〈ξ 〉 .

48 CFR 1552.235-73 - Access to Federal Insecticide, Fungicide, and Rodenticide Act Confidential Business Information...

Code of Federal Regulations, 2010 CFR

2010-10-01

... Insecticide, Fungicide, and Rodenticide Act Confidential Business Information (APR 1996). 1552.235-73 Section... Insecticide, Fungicide, and Rodenticide Act Confidential Business Information (APR 1996). As prescribed in... Act Confidential Business Information (APR 1996) In order to perform duties under the contract, the...

Microscopic evidence of a strain-enhanced ferromagnetic state in LaCoO3 thin films

NASA Astrophysics Data System (ADS)

Park, S.; Ryan, P.; Karapetrova, E.; Kim, J. W.; Ma, J. X.; Shi, J.; Freeland, J. W.; Wu, Weida

2009-08-01

Strain-induced modification of magnetic properties of lightly hole doped epitaxial LaCoO3 thin films on different substrates were studied with variable temperature magnetic force microscopy (MFM). Real space observation at 10 K reveals the formation of the local magnetic clusters on a relaxed film grown on LaAlO3 (001). In contrast, a ferromagnetic ground state has been confirmed for tensile-strained film on SrTiO3 (001), indicating that strain is an important factor in creating the ferromagnetic state. Simultaneous atomic force microscopy and MFM measurements reveal nanoscale defect lines for the tensile-strained films, where the structural defects have a large impact on the local magnetic properties.

Strain Phase Diagram of SrTiO3 Thin Films

NASA Astrophysics Data System (ADS)

He, Feizhou; Shapiro, S. M.

2005-03-01

SrTiO3 thin films were used as a model system to study the effects of strain and epitaxial constraint on structural phase transitions of oxide films. The basic phenomena revealed will apply to a variety of important structural transitions including the ferroelectric transition. Highly strained, epitaxial films of SrTiO3 were grown on different substrates. The structural phase transition temperature Tc increases from 105 K in bulk STO to 167 K for films under tensile strain and 330 K for films with compressive strain. The measured temperature-strain phase diagram is qualitatively consistent with theory [1], however the increase in Tc is much larger than predicted in all cases. The symmetry of the phases involved in the transition is different from the corresponding bulk structures largely because of epitaxial constraint, the clamping effect. Thus the shape of the STO unit cell is tetragonal at all temperatures. The possibility exists of a very unique low temperature phase with orthorhombic symmetry (Cmcm) but tetragonal unit cell shape. More generally, we have characterized at least three different manifestations of the clamping effect, showing it is much more subtle than usually recognized. This work is supported through NSF DMR-0239667, DMR-0132918, by the Research Corp, and at BNL by the US DOE DE-AC02-98CH10886. [1] N. A. Pertsev, A. K. Tagantsev and N. Setter, Phys. Rev. B61, R825 (2000).

Characteristics of the Shiga-toxin-producing enteroaggregative Escherichia coli O104:H4 German outbreak strain and of STEC strains isolated in Spain.

PubMed

Mora, Azucena; Herrrera, Alexandra; López, Cecilia; Dahbi, Ghizlane; Mamani, Rosalia; Pita, Julia M; Alonso, María P; Llovo, José; Bernárdez, María I; Blanco, Jesús E; Blanco, Miguel; Blanco, Jorge

2011-09-01

A Shiga-toxin-producing Escherichia coli (STEC) strain belonging to serotype O104:H4, phylogenetic group B1 and sequence type ST678, with virulence features common to the enteroaggregative E. coli (EAEC) pathotype, was reported as the cause of the recent 2011 outbreak in Germany. The outbreak strain was determined to carry several virulence factors of extraintestinal pathogenic E. coli (ExPEC) and to be resistant to a wide range of antibiotics. There are only a few reports of serotype O104:H4, which is very rare in humans and has never been detected in animals or food. Several research groups obtained the complete genome sequence of isolates of the German outbreak strain as well as the genome sequences of EAEC of serotype O104:H4 strains from Africa. Those findings suggested that horizontal genetic transfer allowed the emergence of the highly virulent Shiga-toxin-producing enteroaggregative E. coli (STEAEC) O104:H4 strain responsible for the outbreak in Germany. Epidemiologic investigations supported a linkage between the outbreaks in Germany and France and traced their origin to fenugreek seeds imported from Africa. However, there has been no isolation of the causative strain O104:H4 from any of the samples of fenugreek seeds analyzed. Following the German outbreak, we conducted a large sampling to analyze the presence of STEC, EAEC, and other types of diarrheagenic E. coli strains in Spanish vegetables. During June and July 2011, 200 vegetable samples from different origins were analyzed. All were negative for the virulent serotype O104:H4 and only one lettuce sample (0.6%) was positive for a STEC strain of serotype O146:H21 (stx1, stx2), considered of low virulence. Despite the single positive case, the hygienic and sanitary quality of Spanish vegetables proved to be quite good. In 195 of the 200 samples (98%), <10 colony-forming units (cfu) of E. coli per gram were detected, and the microbiological levels of all samples were satisfactory (<100 cfu/g). The

Simultaneous Rapid Detection and Serotyping of Cronobacter sakazakii Serotypes O1, O2, and O3 by Using Specific Monoclonal Antibodies

PubMed Central

Scharinger, Eva J.; Dietrich, Richard; Kleinsteuber, Ina; Märtlbauer, Erwin

2016-01-01

Cronobacter sakazakii is a foodborne pathogen associated with rare but often lethal infections in neonates. Powdered infant formula (PIF) represents the most frequent source of infection. Out of the identified serotypes (O1 to O7), O1, O2, and O3 are often isolated from clinical and PIF samples. Serotype-specific monoclonal antibodies (MAbs) suitable for application in enzyme immunoassays (EIAs) for the rapid detection of C. sakazakii have not yet been developed. In this study, we created specific MAbs with the ability to bind to C. sakazakii of serotypes O1, O2, and O3. Characterization by indirect EIAs, immunofluorescence, motility assays, and immunoblotting identified lipopolysaccharide (LPS) and exopolysaccharide (EPS) as the antigenic determinants of the MAbs. The established sandwich EIAs were highly sensitive and were able to detect between 2 × 103 and 9 × 106 CFU/ml. Inclusivity tests confirmed that 93% of serotype O1 strains, 100% of O2 strains, and 87% of O3 strains were detected at low cell counts. No cross-reactivity with >100 strains of Cronobacter spp. and other Enterobacteriaceae was observed, except for that with C. sakazakii serotype O3 and Cronobacter muytjensii serotype O1. Moreover, the sandwich EIAs detected C. sakazakii in PIF samples artificially contaminated with 1 to 10 bacterial cells per 10 g of sample after 15 h of preenrichment. The use of these serotype-specific MAbs not only allows the reliable detection of C. sakazakii strains but also enables simultaneous serotyping in a simple sandwich EIA method. PMID:26850303

A multiple antibiotic and serum resistant oligotrophic strain, Klebsiella pneumoniae MB45 having novel dfrA30, is sensitive to ZnO QDs

PubMed Central

2011-01-01

Background The aim of this study was to describe a novel trimethoprim resistance gene cassette, designated dfrA30, within a class 1 integron in a facultatively oligotrophic, multiple antibiotic and human serum resistant test strain, MB45, in a population of oligotrophic bacteria isolated from the river Mahananda; and to test the efficiency of surface bound acetate on zinc oxide quantum dots (ZnO QDs) as bactericidal agent on MB45. Methods Diluted Luria broth/Agar (10-3) media was used to cultivate the oligotrophic bacteria from water sample. Multiple antibiotic resistant bacteria were selected by employing replica plate method. A rapid assay was performed to determine the sensitivity/resistance of the test strain to human serum. Variable region of class 1 integron was cloned, sequenced and the expression of gene coding for antibiotic resistance was done in Escherichia coli JM 109. Identity of culture was determined by biochemical phenotyping and 16S rRNA gene sequence analyses. A phylogenetic tree was constructed based on representative trimethoprim resistance-mediating DfrA proteins retrieved from GenBank. Growth kinetic studies for the strain MB45 were performed in presence of varied concentrations of ZnO QDs. Results and conclusions The facultatively oligotrophic strain, MB45, resistant to human serum and ten antibiotics trimethoprim, cotrimoxazole, ampicillin, gentamycin, netilmicin, tobramycin, chloramphenicol, cefotaxime, kanamycin and streptomycin, has been identified as a new strain of Klebsiella pneumoniae. A novel dfr gene, designated as dfrA30, found integrated in class 1 integron was responsible for resistance to trimethoprim in Klebsiella pneumoniae strain MB45. The growth of wild strain MB45 was 100% arrested at 500 mg/L concentration of ZnO QDs. To our knowledge this is the first report on application of ZnO quantum dots to kill multiple antibiotics and serum resistant K. pneumoniae strain. PMID:21595893

Understanding the Origin of Ferromagnetism in Strained LaCoO3 Thin Films

NASA Astrophysics Data System (ADS)

Ma, J. X.; Shi, J.; Freeland, J. W.

2009-03-01

Using strain to control the behavior of strongly correlated materials offers new opportunities to control fundamental properties. For the case of magnetism, LaCoO3 offers the ability to use strain through thin film growth to manipulate directly the spin-state of Co in this system. Here we present the results of a detailed polarized x-ray spectroscopy study of LaCoO3 thin films grown on SrTiO3(001) and LaAlO3 (001) substrates. X-ray diffraction from 25 nm thin films confirm the films are fully strained in both cases and, for films under tensile strain, total moment magnetometry shows a clear transition to ferromagnetic state at ˜80K. X-ray absorption shows that the films grown from a LaCoO3 target are slightly hole doped due to non-stoichiometry generated during growth (effective doping ˜ 0.1 holes per unit cell), which in the bulk is sufficient to destroy the low-spin state. However, even though the films are slightly hole doped, the films under tensile strain show long range ferromagnetic order unlike the bulk system. Since the films are insulating, these results are consistent with a ferromagnetic insulating state arising due to superexchange. Work at UCR is supported by ONR/DMEA under award H94003-08-2-0803.

A comparison of Shiga-toxin 2 bacteriophage from classical enterohemorrhagic Escherichia coli serotypes and the German E. coli O104:H4 outbreak strain.

PubMed

Laing, Chad R; Zhang, Yongxiang; Gilmour, Matthew W; Allen, Vanessa; Johnson, Roger; Thomas, James E; Gannon, Victor P J

2012-01-01

Escherichia coli O104:H4 was associated with a severe foodborne disease outbreak originating in Germany in May 2011. More than 4000 illnesses and 50 deaths were reported. The outbreak strain was a typical enteroaggregative E. coli (EAEC) that acquired an antibiotic resistance plasmid and a Shiga-toxin 2 (Stx2)-encoding bacteriophage. Based on whole-genome phylogenies, the O104:H4 strain was most closely related to other EAEC strains; however, Stx2-bacteriophage are mobile, and do not necessarily share an evolutionary history with their bacterial host. In this study, we analyzed Stx2-bacteriophage from the E. coli O104:H4 outbreak isolates and compared them to all available Stx2-bacteriophage sequences. We also compared Stx2 production by an E. coli O104:H4 outbreak-associated isolate (ON-2011) to that of E. coli O157:H7 strains EDL933 and Sakai. Among the E. coli Stx2-phage sequences studied, that from O111:H- strain JB1-95 was most closely related phylogenetically to the Stx2-phage from the O104:H4 outbreak isolates. The phylogeny of most other Stx2-phage was largely concordant with their bacterial host genomes. Finally, O104:H4 strain ON-2011 produced less Stx2 than E. coli O157:H7 strains EDL933 and Sakai in culture; however, when mitomycin C was added, ON-2011 produced significantly more toxin than the E. coli O157:H7 strains. The Stx2-phage from the E. coli O104:H4 outbreak strain and the Stx2-phage from O111:H- strain JB1-95 likely share a common ancestor. Incongruence between the phylogenies of the Stx2-phage and their host genomes suggest the recent Stx2-phage acquisition by E. coli O104:H4. The increase in Stx2-production by ON-2011 following mitomycin C treatment may or may not be related to the high rates of hemolytic uremic syndrome associated with the German outbreak strain. Further studies are required to determine whether the elevated Stx2-production levels are due to bacteriophage or E. coli O104:H4 host related factors.

A Comparison of Shiga-Toxin 2 Bacteriophage from Classical Enterohemorrhagic Escherichia coli Serotypes and the German E. coli O104:H4 Outbreak Strain

PubMed Central

Laing, Chad R.; Zhang, Yongxiang; Gilmour, Matthew W.; Allen, Vanessa; Johnson, Roger; Thomas, James E.; Gannon, Victor P. J.

2012-01-01

Escherichia coli O104:H4 was associated with a severe foodborne disease outbreak originating in Germany in May 2011. More than 4000 illnesses and 50 deaths were reported. The outbreak strain was a typical enteroaggregative E. coli (EAEC) that acquired an antibiotic resistance plasmid and a Shiga-toxin 2 (Stx2)-encoding bacteriophage. Based on whole-genome phylogenies, the O104:H4 strain was most closely related to other EAEC strains; however, Stx2-bacteriophage are mobile, and do not necessarily share an evolutionary history with their bacterial host. In this study, we analyzed Stx2-bacteriophage from the E. coli O104:H4 outbreak isolates and compared them to all available Stx2-bacteriophage sequences. We also compared Stx2 production by an E. coli O104:H4 outbreak-associated isolate (ON-2011) to that of E. coli O157:H7 strains EDL933 and Sakai. Among the E. coli Stx2-phage sequences studied, that from O111:H- strain JB1-95 was most closely related phylogenetically to the Stx2-phage from the O104:H4 outbreak isolates. The phylogeny of most other Stx2-phage was largely concordant with their bacterial host genomes. Finally, O104:H4 strain ON-2011 produced less Stx2 than E. coli O157:H7 strains EDL933 and Sakai in culture; however, when mitomycin C was added, ON-2011 produced significantly more toxin than the E. coli O157:H7 strains. The Stx2-phage from the E. coli O104:H4 outbreak strain and the Stx2-phage from O111:H- strain JB1-95 likely share a common ancestor. Incongruence between the phylogenies of the Stx2-phage and their host genomes suggest the recent Stx2-phage acquisition by E. coli O104:H4. The increase in Stx2-production by ON-2011 following mitomycin C treatment may or may not be related to the high rates of hemolytic uremic syndrome associated with the German outbreak strain. Further studies are required to determine whether the elevated Stx2-production levels are due to bacteriophage or E. coli O104:H4 host related factors. PMID:22649523

Complete genome sequence of enterohemorrhagic Escherichia coli O157:H7 and genomic comparison with a laboratory strain K-12.

PubMed

Hayashi, T; Makino, K; Ohnishi, M; Kurokawa, K; Ishii, K; Yokoyama, K; Han, C G; Ohtsubo, E; Nakayama, K; Murata, T; Tanaka, M; Tobe, T; Iida, T; Takami, H; Honda, T; Sasakawa, C; Ogasawara, N; Yasunaga, T; Kuhara, S; Shiba, T; Hattori, M; Shinagawa, H

2001-02-28

Escherichia coli O157:H7 is a major food-borne infectious pathogen that causes diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome. Here we report the complete chromosome sequence of an O157:H7 strain isolated from the Sakai outbreak, and the results of genomic comparison with a benign laboratory strain, K-12 MG1655. The chromosome is 5.5 Mb in size, 859 Kb larger than that of K-12. We identified a 4.1-Mb sequence highly conserved between the two strains, which may represent the fundamental backbone of the E. coli chromosome. The remaining 1.4-Mb sequence comprises of O157:H7-specific sequences, most of which are horizontally transferred foreign DNAs. The predominant roles of bacteriophages in the emergence of O157:H7 is evident by the presence of 24 prophages and prophage-like elements that occupy more than half of the O157:H7-specific sequences. The O157:H7 chromosome encodes 1632 proteins and 20 tRNAs that are not present in K-12. Among these, at least 131 proteins are assumed to have virulence-related functions. Genome-wide codon usage analysis suggested that the O157:H7-specific tRNAs are involved in the efficient expression of the strain-specific genes. A complete set of the genes specific to O157:H7 presented here sheds new insight into the pathogenicity and the physiology of O157:H7, and will open a way to fully understand the molecular mechanisms underlying the O157:H7 infection.

First-principles study of strain-induced ferromagnetism in LaCoO3

NASA Astrophysics Data System (ADS)

Seo, Hosung; Demkov, Alexander

2011-03-01

We study theoretically the effect of biaxial strain on magnetic properties of LaCo O3 (LCO) using density functional theory combined with the Hubbard U method. LCO is normally a non-magnetic insulator with trivalent cobalt ions in low-spin state (t 2g 6) . Owing to close interplay between orbital, spin, and lattice degrees of freedom, it shows rich magnetic behavior such as temperature-induced spin state transition. Recently, the ferromagnetic tensile-strained LCO films have been reported. The underlying physics of the ferromagnetic state is, however, unclear. Using a large tetragonal cell we calculate full structural response of the system to applied strain for non-magnetic and magnetic solutions. We show that beyond tensile strain of 3.8% the ferromagnetic solution with Co ions in intermediate-spin state (t 2g 5 e g 1) is stabilized accompanied by partial untilting of Co O6 octahedral network. We also perform the calculation for compressive-strained structures and the difference between these and the tensile strained structures will be presented.

Impact of strain on electronic defects in (Mg,Zn)O thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schmidt, Florian, E-mail: fschmidt@physik.uni-leipzig.de; Müller, Stefan; Wenckstern, Holger von

2014-09-14

We have investigated the impact of strain on the incorporation and the properties of extended and point defects in (Mg,Zn)O thin films by means of photoluminescence, X-ray diffraction, deep-level transient spectroscopy (DLTS), and deep-level optical spectroscopy. The recombination line Y₂, previously detected in ZnO thin films grown on an Al-doped ZnO buffer layer and attributed to tensile strain, was exclusively found in (Mg,Zn)O samples being under tensile strain and is absent in relaxed or compressively strained thin films. Furthermore a structural defect E3´ can be detected via DLTS measurements and is only incorporated in tensile strained samples. Finally it ismore » shown that the omnipresent deep-level E3 in ZnO can only be optically recharged in relaxed ZnO samples.« less

Reversible strain effect on the magnetization of LaCoO3 films

NASA Astrophysics Data System (ADS)

Herklotz, A.; Rata, A. D.; Schultz, L.; Dörr, K.

2009-03-01

The magnetization (M) of a LaCoO3 film grown epitaxially on a piezoelectric substrate has been investigated in dependence on the biaxial in-plane strain. M decreases with the reversible release of tensile strain, with a maximum change of at least 6% per 0.1% of biaxial strain near the Curie temperature (TC) . The biaxial strain response of TC is estimated to be below 5 K/% in the tensile strain state. This is in agreement with results from statically strained films on various substrates. As possible origins of the strain-induced magnetization are considered (i) the strain-dependent Curie temperature, (ii) a strain-dependent magnetically inhomogeneous (phase-separated) state, and (iii) a strain-dependent magnetic moment (spin state) of Co ions. The TC shift is found insufficient to explain the measured strain-induced magnetization change but contributions from mechanism (ii) or (iii) must be involved.

Simultaneous Rapid Detection and Serotyping of Cronobacter sakazakii Serotypes O1, O2, and O3 by Using Specific Monoclonal Antibodies.

PubMed

Scharinger, Eva J; Dietrich, Richard; Kleinsteuber, Ina; Märtlbauer, Erwin; Schauer, Kristina

2016-04-01

Cronobacter sakazakii is a foodborne pathogen associated with rare but often lethal infections in neonates. Powdered infant formula (PIF) represents the most frequent source of infection. Out of the identified serotypes (O1 to O7), O1, O2, and O3 are often isolated from clinical and PIF samples. Serotype-specific monoclonal antibodies (MAbs) suitable for application in enzyme immunoassays (EIAs) for the rapid detection of C. sakazakii have not yet been developed. In this study, we created specific MAbs with the ability to bind toC. sakazakii of serotypes O1, O2, and O3. Characterization by indirect EIAs, immunofluorescence, motility assays, and immunoblotting identified lipopolysaccharide (LPS) and exopolysaccharide (EPS) as the antigenic determinants of the MAbs. The established sandwich EIAs were highly sensitive and were able to detect between 2 × 10(3)and 9 × 10(6)CFU/ml. Inclusivity tests confirmed that 93% of serotype O1 strains, 100% of O2 strains, and 87% of O3 strains were detected at low cell counts. No cross-reactivity with >100 strains of Cronobacter spp. and other Enterobacter iaceae was observed, except for that with C. sakazakii serotype O3 and Cronobacter muytjensii serotype O1. Moreover, the sandwich EIAs detected C. sakazakii in PIF samples artificially contaminated with 1 to 10 bacterial cells per 10 g of sample after 15 h of preenrichment. The use of these serotype-specific MAbs not only allows the reliable detection of C. sakazakii strains but also enables simultaneous serotyping in a simple sandwich EIA method. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

Detection of virulent Escherichia coli O157 strains using multiplex PCR and single base sequencing for SNP characterization.

PubMed

Haugum, K; Brandal, L T; Løbersli, I; Kapperud, G; Lindstedt, B-A

2011-06-01

To compare 167 Norwegian human and nonhuman Escherichia coli O157:H7/NM (nonmotile) isolates with respect to an A/T single nucleotide polymorphism (SNP) in the tir gene and to detect specific SNPs that differentiate STEC O157 into distinct virulence clades (1-3 and 8). We developed a multiplex PCR followed by single base sequencing for detection of the SNPs, and examined the association among SNP genotype, virulence profile (stx and eae status), multilocus variable number of tandem repeats analysis (MLVA) profile and clinical outcome. We found an over-representation of the T allele among human strains compared to nonhuman strains, including 5/6 haemolytic-uraemic syndrome cases. Fourteen strains belonged to clade 8, followed by two clade 2 strains. No clade 1 nor 3 isolates were observed. stx1 in combination with either stx2(EDL933) or stx2c were frequently observed among human strains, whereas stx2c was dominating in nonhuman strains. MLVA indicated that only single cases or small outbreaks with E. coli O157 have been observed in Norway through the years 1993-2008. We observed that the tir-255 A/T SNP and the stx status were different between human and nonhuman O157 strains. No major outbreaks were observed, and only a few strains were differentiated into the virulence clades 2 and 8. The detection of virulence clade-specific SNPs enables the rapid designation of virulent E. coli O157 strains, especially in outbreak situations. © 2011 The Authors. Journal of Applied Microbiology © 2011 The Society for Applied Microbiology.

48 CFR 1552.217-77 - Option to extend the term of the contract fixed price.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Option to extend the term... Provisions and Clauses 1552.217-77 Option to extend the term of the contract fixed price. As prescribed in 1517.208(g), insert the following clause: Option To Extend the Term of the Contract Fixed Price (OCT...

Multiferroic Properties of o-LuMnO3 Controlled by b-Axis Strain

NASA Astrophysics Data System (ADS)

Windsor, Y. W.; Huang, S. W.; Hu, Y.; Rettig, L.; Alberca, A.; Shimamoto, K.; Scagnoli, V.; Lippert, T.; Schneider, C. W.; Staub, U.

2014-10-01

Strain is a leading candidate for controlling magnetoelectric coupling in multiferroics. Here, we use x-ray diffraction to study the coupling between magnetic order and structural distortion in epitaxial films of the orthorhombic (o-) perovskite LuMnO3. An antiferromagnetic spin canting in the E-type magnetic structure is shown to be related to the ferroelectrically induced structural distortion and to a change in the magnetic propagation vector. By comparing films of different orientations and thicknesses, these quantities are found to be controlled by b-axis strain. It is shown that compressive strain destabilizes the commensurate E-type structure and reduces its accompanying ferroelectric distortion.

Multiferroic properties of o-LuMnO3 controlled by b-axis strain.

PubMed

Windsor, Y W; Huang, S W; Hu, Y; Rettig, L; Alberca, A; Shimamoto, K; Scagnoli, V; Lippert, T; Schneider, C W; Staub, U

2014-10-17

Strain is a leading candidate for controlling magnetoelectric coupling in multiferroics. Here, we use x-ray diffraction to study the coupling between magnetic order and structural distortion in epitaxial films of the orthorhombic (o-) perovskite LuMnO(3). An antiferromagnetic spin canting in the E-type magnetic structure is shown to be related to the ferroelectrically induced structural distortion and to a change in the magnetic propagation vector. By comparing films of different orientations and thicknesses, these quantities are found to be controlled by b-axis strain. It is shown that compressive strain destabilizes the commensurate E-type structure and reduces its accompanying ferroelectric distortion.

Job strain and resting heart rate: a cross-sectional study in a Swedish random working sample.

PubMed

Eriksson, Peter; Schiöler, Linus; Söderberg, Mia; Rosengren, Annika; Torén, Kjell

2016-03-05

Numerous studies have reported an association between stressing work conditions and cardiovascular disease. However, more evidence is needed, and the etiological mechanisms are unknown. Elevated resting heart rate has emerged as a possible risk factor for cardiovascular disease, but little is known about the relation to work-related stress. This study therefore investigated the association between job strain, job control, and job demands and resting heart rate. We conducted a cross-sectional survey of randomly selected men and women in Västra Götalandsregionen, Sweden (West county of Sweden) (n = 1552). Information about job strain, job demands, job control, heart rate and covariates was collected during the period 2001-2004 as part of the INTERGENE/ADONIX research project. Six different linear regression models were used with adjustments for gender, age, BMI, smoking, education, and physical activity in the fully adjusted model. Job strain was operationalized as the log-transformed ratio of job demands over job control in the statistical analyses. No associations were seen between resting heart rate and job demands. Job strain was associated with elevated resting heart rate in the unadjusted model (linear regression coefficient 1.26, 95 % CI 0.14 to 2.38), but not in any of the extended models. Low job control was associated with elevated resting heart rate after adjustments for gender, age, BMI, and smoking (linear regression coefficient -0.18, 95 % CI -0.30 to -0.02). However, there were no significant associations in the fully adjusted model. Low job control and job strain, but not job demands, were associated with elevated resting heart rate. However, the observed associations were modest and may be explained by confounding effects.

Phase transition induced strain in ZnO under high pressure

DOE PAGES

Yan, Xiaozhi; Dong, Haini; Li, Yanchun; ...

2016-05-13

Under high pressure, the phase transition mechanism and mechanical property of material are supposed to be largely associated with the transformation induced elastic strain. However, the experimental evidences for such strain are scanty. The elastic and plastic properties of ZnO, a leading material for applications in chemical sensor, catalyst, and optical thin coatings, were determined using in situ high pressure synchrotron axial and radial x-ray diffraction. The abnormal elastic behaviors of selected lattice planes of ZnO during phase transition revealed the existence of internal elastic strain, which arise from the lattice misfit between wurtzite and rocksalt phase. Furthermore, the strengthmore » decrease of ZnO during phase transition under non-hydrostatic pressure was observed and could be attributed to such internal elastic strain, unveiling the relationship between pressure induced internal strain and mechanical property of material. Ultimately, these findings are of fundamental importance to understanding the mechanism of phase transition and the properties of materials under pressure.« less

Metabolism of hexadecyltrimethylammonium chloride in Pseudomonas strain B1.

PubMed Central

van Ginkel, C G; van Dijk, J B; Kroon, A G

1992-01-01

A bacterium (strain B1) utilizing hexadecyltrimethylammonium chloride as a carbon and energy source was isolated from activated sludge and tentatively identified as a Pseudomonas sp. This bacterium only grew on alkyltrimethylammonium salts (C12 to C22) and possible intermediates of hexadecyltrimethylammonium chloride breakdown such as hexadecanoate and acetate. Pseudomonas strain B1 did not grow on amines. Simultaneous adaptation studies suggested that the bacterium oxidized only the alkyl chain of hexadecyltrimethylammonium chloride. This was confirmed by the stoichiometric formation of trimethylamine from hexadecyltrimethylammonium chloride. The initial hexadecyltrimethylammonium chloride oxygenase activity, measured by its ability to form trimethylamine, was NAD(P)H and O2 dependent. Finally, assays of aldehyde dehydrogenase, hexadecanoyl-coenzyme A dehydrogenase, and isocitrate lyase in cell extracts revealed the potential of Pseudomonas strain B1 to metabolize the alkyl chain via beta-oxidation. PMID:1444422

The highly virulent 2006 Norwegian EHEC O103:H25 outbreak strain is related to the 2011 German O104:H4 outbreak strain.

PubMed

L'Abée-Lund, Trine M; Jørgensen, Hannah J; O'Sullivan, Kristin; Bohlin, Jon; Ligård, Goro; Granum, Per Einar; Lindbäck, Toril

2012-01-01

In 2006, a severe foodborne EHEC outbreak occured in Norway. Seventeen cases were recorded and the HUS frequency was 60%. The causative strain, Esherichia coli O103:H25, is considered to be particularly virulent. Sequencing of the outbreak strain revealed resemblance to the 2011 German outbreak strain E. coli O104:H4, both in genome and Shiga toxin 2-encoding (Stx2) phage sequence. The nucleotide identity between the Stx2 phages from the Norwegian and German outbreak strains was 90%. During the 2006 outbreak, stx(2)-positive O103:H25 E. coli was isolated from two patients. All the other outbreak associated isolates, including all food isolates, were stx-negative, and carried a different phage replacing the Stx2 phage. This phage was of similar size to the Stx2 phage, but had a distinctive early phage region and no stx gene. The sequence of the early region of this phage was not retrieved from the bacterial host genome, and the origin of the phage is unknown. The contaminated food most likely contained a mixture of E. coli O103:H25 cells with either one of the phages.

The Highly Virulent 2006 Norwegian EHEC O103:H25 Outbreak Strain Is Related to the 2011 German O104:H4 Outbreak Strain

PubMed Central

L'Abée-Lund, Trine M.; Jørgensen, Hannah J.; O'Sullivan, Kristin; Bohlin, Jon; Ligård, Goro; Granum, Per Einar; Lindbäck, Toril

2012-01-01

In 2006, a severe foodborne EHEC outbreak occured in Norway. Seventeen cases were recorded and the HUS frequency was 60%. The causative strain, Esherichia coli O103:H25, is considered to be particularly virulent. Sequencing of the outbreak strain revealed resemblance to the 2011 German outbreak strain E. coli O104:H4, both in genome and Shiga toxin 2-encoding (Stx2) phage sequence. The nucleotide identity between the Stx2 phages from the Norwegian and German outbreak strains was 90%. During the 2006 outbreak, stx2-positive O103:H25 E. coli was isolated from two patients. All the other outbreak associated isolates, including all food isolates, were stx-negative, and carried a different phage replacing the Stx2 phage. This phage was of similar size to the Stx2 phage, but had a distinctive early phage region and no stx gene. The sequence of the early region of this phage was not retrieved from the bacterial host genome, and the origin of the phage is unknown. The contaminated food most likely contained a mixture of E. coli O103:H25 cells with either one of the phages. PMID:22403614

Strain-Gradient Modulated Exciton Emission in Bent ZnO Wires Probed by Cathodoluminescence.

PubMed

Fu, Xue-Wen; Li, Cai-Zhen; Fang, Liang; Liu, Da-Meng; Xu, Jun; Yu, Da-Peng; Liao, Zhi-Min

2016-12-27

Photoelectrical properties of semiconductor nanostructures are expected to be improved significantly by strain engineering. Besides the local strain, the strain gradient is promising to tune the luminescence properties by modifying the crystal symmetry. Here, we report the investigation of strain-gradient induced symmetry-breaking effect on excitonic states in pure bending ZnO microwires by high spatial-resolved cathodoluminescence at low temperature of 80 K. In addition to the local-strain induced light emission peak shift, the bound exciton emission photon energy shows an extraordinary jump of ∼16.6 meV at a high strain-gradient of 1.22% μm -1 , which is ascribed to the strain gradient induced symmetry-breaking. Such a symmetry-breaking lifts the energy degeneracy of the electronic band structures, which significantly modifies the electron-hole interactions and the fine structures of the bound exciton states. These results provide a further understanding of the strain gradient effect on the excitonic states and possess a potential for the applications in optoelectronic devices.

Cell surface characteristics of environmental and clinical isolates of Vibrio cholerae non-O1.

PubMed Central

Chaudhuri, K; Bhadra, R K; Das, J

1992-01-01

The cell surfaces of several toxigenic and nontoxigenic environmental and clinical isolates of Vibrio cholerae non-O1 have been examined. The environmental strains, irrespective of toxigenicity, are significantly more resistant to antibiotics and detergents than are V. cholerae O1 strains. The clinical isolates of non-O1 vibrios are as sensitive to a wide variety of chemicals as the O1 vibrios. The environmental non-O1 strains are also less susceptible to lysis when treated with protein denaturants or neutral and anionic detergents than are O1 vibrios and the clinical non-O1 strains. In contrast to O1 vibrios, the environmental non-O1 vibrios do not have exposed phospholipids in their outer membranes. These features of the cell surfaces of environmental non-O1 vibrios might have a role in the better survival of these organisms under environmental fluctuations. Images PMID:1282793

48 CFR 1552.235-78 - Data Security for Toxic Substances Control Act Confidential Business Information (DEC 1997).

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2014-10-01

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Code of Federal Regulations, 2011 CFR

2011-10-01

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Code of Federal Regulations, 2010 CFR

2010-10-01

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Confinement- and strain-induced enhancement of thermoelectric properties in LaNiO3/LaAlO3(001 ) superlattices

NASA Astrophysics Data System (ADS)

Geisler, Benjamin; Pentcheva, Rossitza

2018-05-01

By combining ab initio simulations including an on-site Coulomb repulsion term and Boltzmann theory, we explore the thermoelectric properties of (LaNiO3)n /(LaAlO3)n (001) superlattices (n =1 ,3 ) and identify a strong dependence on confinement, spacer thickness, and epitaxial strain. While the system with n =3 shows modest values of the Seebeck coefficient and power factor, the simultaneous reduction of the LaNiO3 region and the LaAlO3 spacer thickness to single layers results in a strong enhancement, in particular of the in-plane values. This effect can be further tuned by using epitaxial strain as a control parameter: Under tensile strain corresponding to the lateral lattice constant of SrTiO3 we predict in- and cross-plane Seebeck coefficients of ±600 μ V /K and an in-plane power factor of 11 μ W /K2cm for an estimated relaxation time of τ =4 fs around room temperature. These values are comparable to some of the best performing oxide systems such as La-doped SrTiO3 or layered cobaltates and are associated with the opening of a small gap (0.29 eV) induced by the concomitant effect of octahedral tilting and Ni-site disproportionation. This establishes oxide superlattices at the verge of a metal-to-insulator transition driven by confinement and strain as promising candidates for thermoelectric materials.

Genetic Traits of Vibrio cholerae O1 Haitian Isolates That Are Absent in Contemporary Strains from Kolkata, India

PubMed Central

Ghosh, Priyanka; Naha, Arindam; Pazhani, G. P.; Ramamurthy, T.; Mukhopadhyay, Asish K.

2014-01-01

The world's worst cholera epidemic in Haiti (2010) coerced to trace the origin and dissemination of the causative agent Vibrio cholerae O1 for proper management of cholera. Sequence analysis of the Haitian strain showed several variations in the genes encoding cholera toxin B subunit (ctxB); toxin-co-regulated pilus (tcpA), repeat in toxins (rtxA), quinolone resistance-determining region (QRDR) of gyrase A (gyrA), rstB of RS element along with the change in the number of repeat sequences at the promoter region of ctxAB. Our earlier studies showed that variant tcpA (tcpA CIRS) and ctxB (ctxB7) first appeared in Kolkata during 2003 and 2006, respectively. The present study revealed that a variant rtxA was first isolated in Kolkata during 2004 and probably formed the genetic background for the emergence of the ctxB7 allele as we were unable to detect a single strain with the combination of El Tor rtxA and ctxB7. The variant gyrA was first time detected in Kolkata during 1994. The Kolkata strains contained four heptad repeats (TTTTGAT) in their CT promoter regions whereas Haitian strains carried 5 heptad repeats. Haitian strains had 3 nucleotide deletions at the rstB gene, which is a unique feature of the classical biotype strains. But the Kolkata strains did not have such deletion mutations in the rstB. Our study demonstrated the existence of some Haitian genetic traits in Kolkata isolates along with the dissimilarities in genomic content with respect to rstB and ctxAB promoter region. Finally, we conclude that Haitian variant strain may be evolved due to sequential event in the Indian subcontinent strain with some cryptic modification in the genome. PMID:25415339

The virulence factor ychO has a pleiotropic action in an Avian Pathogenic Escherichia coli (APEC) strain.

PubMed

Pilatti, Livia; Boldrin de Paiva, Jacqueline; Rojas, Thaís Cabrera Galvão; Leite, Janaína Luisa; Conceição, Rogério Arcuri; Nakazato, Gerson; Dias da Silveira, Wanderley

2016-03-10

Avian pathogenic Escherichia coli strains cause extraintestinal diseases in birds, leading to substantial economic losses to the poultry industry worldwide. Bacteria that invade cells can overcome the host humoral immune response, resulting in a higher pathogenicity potential. Invasins are members of a large family of outer membrane proteins that allow pathogen invasion into host cells by interacting with specific receptors on the cell surface. An in silico analysis of the genome of a septicemic APEC strain (SEPT362) demonstrated the presence of a putative invasin homologous to the ychO gene from E. coli str. K-12 substr. MG1655. In vitro and in vivo assays comparing a mutant strain carrying a null mutation of this gene, a complemented strain, and its counterpart wild-type strain showed that ychO plays a role in the pathogenicity of APEC strain SEPT362. In vitro assays demonstrated that the mutant strain exhibited significant decreases in bacterial adhesiveness and invasiveness in chicken cells and biofilm formation. In vivo assay indicated a decrease in pathogenicity of the mutant strain. Moreover, transcriptome analysis demonstrated that the ychO deletion affected the expression of 426 genes. Among the altered genes, 93.66% were downregulated in the mutant, including membrane proteins and metabolism genes. The results led us to propose that gene ychO contributes to the pathogenicity of APEC strain SEPT362 influencing, in a pleiotropic manner, many biological characteristics, such as adhesion and invasion of in vitro cultured cells, biofilm formation and motility, which could be due to the possible membrane location of this protein. All of these results suggest that the absence of gene ychO would influence the virulence of the APEC strain herein studied.

Anti-neuroinflammatory effect of 6,8,1'-tri-O-methylaverantin, a metabolite from a marine-derived fungal strain Aspergillus sp., via upregulation of heme oxygenase-1 in lipopolysaccharide-activated microglia.

PubMed

Kim, Kwan-Woo; Kim, Hye Jin; Sohn, Jae Hak; Yim, Joung Han; Kim, Youn-Chul; Oh, Hyuncheol

2018-02-01

In the course of searching for anti-neuroinflammatory metabolites from marine-derived fungi, three fungal metabolites, 6,8,1'-tri-O-methylaverantin, 6,8-di-O-methylaverufin, and 5-methoxysterigmatocystin were isolated from a marine-derived fungal strain Aspergillus sp. SF-6796. Among these, 6,8,1'-tri-O-methylaverantin induced the expression of heme oxygenase (HO)-1 protein in BV2 microglial cells. The induction of HO-1 protein was mediated by the activation of nuclear transcription factor erythroid-2 related factor 2 (Nrf2), and was regulated by the p38 mitogen-activated protein kinase and phosphatidylinositol 3-kinase/protein kinase B signaling pathways. Furthermore, 6,8,1'-tri-O-methylaverantin suppressed the overproduction of pro-inflammatory mediators, such as nitric oxide, prostaglandin E 2 , inducible nitric oxide synthase, and cyclooxygenase-2 in lipopolysaccharide (LPS)-stimulated BV2 microglial cells. These anti-neuroinflammatory effects were mediated through the negative regulation of the nuclear factor kappa B pathway, repressing the phosphorylation and degradation of inhibitor kappa B-α, translocation into the nucleus of p65/p50 heterodimer, and DNA-binding activity of p65 subunit. The anti-neuroinflammatory effect of 6,8,1'-tri-O-methylaverantin was partially blocked by a selective HO-1 inhibitor, suggesting that its anti-neuroinflammatory effect is at least partly mediated by HO-1 induction. In this study, 6,8,1'-tri-O-methylaverantin also induced HO-1 protein expression in primary microglial cells, and this correlated with anti-neuroinflammatory effects observed in LPS-stimulated primary microglial cells. In conclusion, 6,8,1'-tri-O-methylaverantin represents a potential candidate for use in the development of therapeutic agents for the regulation of neuroinflammation in neurodegenerative diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

Growth of highly strained CeO 2 ultrathin films

DOE PAGES

Shi, Yezhou; Lee, Sang Chul; Monti, Matteo; ...

2016-11-07

Large biaxial strain is a promising route to tune the functionalities of oxide thin films. However, large strain is often not fully realized due to the formation of misfit dislocations at the film/substrate interface. In this work, we examine the growth of strained ceria (CeO 2) thin films on (001)-oriented single crystal yttria-stabilized zirconia (YSZ) via pulsed-laser deposition. By varying the film thickness systematically between 1 and 430 nm, we demonstrate that ultrathin ceria films are coherently strained to the YSZ substrate for thicknesses up to 2.7 nm, despite the large lattice mismatch (~5%). The coherency is confirmed by bothmore » X-ray diffraction and high-resolution transmission electron microscopy. This thickness is several times greater than the predicted equilibrium critical thickness. Partial strain relaxation is achieved by forming semirelaxed surface islands rather than by directly nucleating dislocations. In situ reflective high-energy electron diffraction during growth confirms the transition from 2-D (layer-by-layer) to 3-D (island) at a film thickness of ~1 nm, which is further supported by atomic force microscopy. We propose that dislocations likely nucleate near the surface islands and glide to the film/substrate interface, as evidenced by the presence of 60° dislocations. Finally, an improved understanding of growing oxide thin films with a large misfit lays the foundation to systematically explore the impact of strain and dislocations on properties such as ionic transport and redox chemistry.« less

Estimation of lattice strain in nanocrystalline RuO2 by Williamson-Hall and size-strain plot methods

NASA Astrophysics Data System (ADS)

Sivakami, R.; Dhanuskodi, S.; Karvembu, R.

2016-01-01

RuO2 nanoparticles (RuO2 NPs) have been successfully synthesized by the hydrothermal method. Structure and the particle size have been determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM). UV-Vis spectra reveal that the optical band gap of RuO2 nanoparticles is red shifted from 3.95 to 3.55 eV. BET measurements show a high specific surface area (SSA) of 118-133 m2/g and pore diameter (10-25 nm) has been estimated by Barret-Joyner-Halenda (BJH) method. The crystallite size and lattice strain in the samples have been investigated by Williamson-Hall (W-H) analysis assuming uniform deformation, deformation stress and deformation energy density, and the size-strain plot method. All other relevant physical parameters including stress, strain and energy density have been calculated. The average crystallite size and the lattice strain evaluated from XRD measurements are in good agreement with the results of TEM.

Ganglioside GM1 mimicry in Campylobacter strains from sporadic infections in the United States.

PubMed

Nachamkin, I; Ung, H; Moran, A P; Yoo, D; Prendergast, M M; Nicholson, M A; Sheikh, K; Ho, T; Asbury, A K; McKhann, G M; Griffin, J W

1999-05-01

To determine whether GM1-like epitopes in Campylobacter species are specific to O serotypes associated with Guillain-Barré syndrome (GBS) or whether they are frequent among random Campylobacter isolates causing enteritis, 275 random enteritis-associated isolates of Campylobacter jejuni were analyzed. To determine whether GM1-like epitopes in Campylobacter species are specific to O serotypes associated with Guillan-Barre syndrome (GBS) or whether they are frequent among random Campylobacter isolates causing enteritis, 275 enteritis-associated isolates, randomly collected in the United States, were analyzed using a cholera-toxin binding assay [corrected]. Overall, 26.2% of the isolates were positive for the GM1-like epitope. Of the 36 different O serotypes in the sample, 21 (58.3%) contained no strains positive for GM1, whereas in 6 serotypes (16.7%), >50% of isolates were positive for GM1. GBS-associated serotypes were more likely to contain strains positive for GM1 than were non-GBS-associated serotypes (37.8% vs. 15.1%, P=.0116). The results suggest that humans are frequently exposed to strains exhibiting GM1-like mimicry and, while certain serotypes may be more likely to possess GM1-like epitopes, the presence of GM1-like epitopes on Campylobacter strains does not itself trigger GBS.

Strain-induced optical band gap variation of SnO 2 films

DOE PAGES

Rus, Stefania Florina; Ward, Thomas Zac; Herklotz, Andreas

2016-06-29

In this paper, thickness dependent strain relaxation effects are utilized to study the impact of crystal anisotropy on the optical band gap of epitaxial SnO 2 films grown by pulsed laser deposition on (0001)-oriented sapphire substrates. An X-ray diffraction analysis reveals that all films are under tensile biaxial in-plane strain and that strain relaxation occurs with increasing thickness. Variable angle spectroscopic ellipsometry shows that the optical band gap of the SnO 2 films continuously increases with increasing film thickness. This increase in the band gap is linearly related to the strain state of the films, which indicates that the mainmore » origin of the band gap change is strain relaxation. The experimental observation is in excellent agreement with results from density functional theory for biaxial in-plane strain. Our research demonstrates that strain is an effective way to tune the band gap of SnO 2 films and suggests that strain engineering is an appealing route to tailor the optical properties of oxide semiconductors.« less

48 CFR 1552.224-70 - Social security numbers of consultants and certain sole proprietors and Privacy Act statement.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 48 Federal Acquisition Regulations System 6 2010-10-01 2010-10-01 true Social security numbers of... Acquisition Regulations System ENVIRONMENTAL PROTECTION AGENCY CLAUSES AND FORMS SOLICITATION PROVISIONS AND CONTRACT CLAUSES Texts of Provisions and Clauses 1552.224-70 Social security numbers of consultants and...

Structure of the LPS O-chain from Fusobacterium nucleatum strain 10953, containing sialic acid

PubMed Central

Vinogradov, Evgeny; St. Michael, Frank; Homma, Kiyonobu; Sharma, Ashu; Cox, Andrew D.

2017-01-01

Fusobacterium nucleatum is an anaerobic bacterium found in the human mouth where it causes periodontitis. Recently, it has been gaining attention as a potential causative agent for colorectal cancer and is strongly linked with pregnancy complications including pre-term and still births. Little is known about virulence factors of this organism and thus we have initiated studies to examine the bacterial surface glycochemistry. Consistent with a recent paper suggesting that F. nucleatum strain 10593 can synthesize sialic acid, a staining technique identified sialic acid on the bacterial surface. We isolated lipopolysaccharide from this F. nucleatum strain and performed structural analysis on the O-antigen. Our studies identified a trisaccharide repeating unit of the O-antigen with the following structure: -[→4)-α-Neup5Ac-(2→4)-β-D-Galp-(1→3)-α-D-FucpNAc4NAc-(1-]-where Ac indicates 4-N-acetylation of ∼30% FucNAc4N residues. The presence of sialic acid as a constituent of the O-antigen is consistent with recent data identifying de novo sialic acid synthesis in this strain. PMID:28199859

Y4lO of Rhizobium sp. Strain NGR234 Is a Symbiotic Determinant Required for Symbiosome Differentiation▿

PubMed Central

Yang, Feng-Juan; Cheng, Li-Li; Zhang, Ling; Dai, Wei-Jun; Liu, Zhe; Yao, Nan; Xie, Zhi-Ping; Staehelin, Christian

2009-01-01

Type 3 (T3) effector proteins, secreted by nitrogen-fixing rhizobia with a bacterial T3 secretion system, affect the nodulation of certain host legumes. The open reading frame y4lO of Rhizobium sp. strain NGR234 encodes a protein with sequence similarities to T3 effectors from pathogenic bacteria (the YopJ effector family). Transcription studies showed that the promoter activity of y4lO depended on the transcriptional activator TtsI. Recombinant Y4lO protein expressed in Escherichia coli did not acetylate two representative mitogen-activated protein kinase kinases (human MKK6 and MKK1 from Medicago truncatula), indicating that YopJ-like proteins differ with respect to their substrate specificities. The y4lO gene was mutated in NGR234 (strain NGRΩy4lO) and in NGRΩnopL, a mutant that does not produce the T3 effector NopL (strain NGRΩnopLΩy4lO). When used as inoculants, the symbiotic properties of the mutants differed. Tephrosia vogelii, Phaseolus vulgaris cv. Yudou No. 1, and Vigna unguiculata cv. Sui Qing Dou Jiao formed pink effective nodules with NGR234 and NGRΩnopLΩy4lO. Nodules induced by NGRΩy4lO were first pink but rapidly turned greenish (ineffective nodules), indicating premature senescence. An ultrastructural analysis of the nodules induced by NGRΩy4lO revealed abnormal formation of enlarged infection droplets in ineffective nodules, whereas symbiosomes harboring a single bacteroid were frequently observed in effective nodules induced by NGR234 or NGRΩnopLΩy4lO. It is concluded that Y4lO is a symbiotic determinant involved in the differentiation of symbiosomes. Y4lO mitigated senescence-inducing effects caused by the T3 effector NopL, suggesting synergistic effects for Y4lO and NopL in nitrogen-fixing nodules. PMID:19060155

Y4lO of Rhizobium sp. strain NGR234 is a symbiotic determinant required for symbiosome differentiation.

PubMed

Yang, Feng-Juan; Cheng, Li-Li; Zhang, Ling; Dai, Wei-Jun; Liu, Zhe; Yao, Nan; Xie, Zhi-Ping; Staehelin, Christian

2009-02-01

Type 3 (T3) effector proteins, secreted by nitrogen-fixing rhizobia with a bacterial T3 secretion system, affect the nodulation of certain host legumes. The open reading frame y4lO of Rhizobium sp. strain NGR234 encodes a protein with sequence similarities to T3 effectors from pathogenic bacteria (the YopJ effector family). Transcription studies showed that the promoter activity of y4lO depended on the transcriptional activator TtsI. Recombinant Y4lO protein expressed in Escherichia coli did not acetylate two representative mitogen-activated protein kinase kinases (human MKK6 and MKK1 from Medicago truncatula), indicating that YopJ-like proteins differ with respect to their substrate specificities. The y4lO gene was mutated in NGR234 (strain NGROmegay4lO) and in NGR Omega nopL, a mutant that does not produce the T3 effector NopL (strain NGR Omega nopLOmegay4lO). When used as inoculants, the symbiotic properties of the mutants differed. Tephrosia vogelii, Phaseolus vulgaris cv. Yudou No. 1, and Vigna unguiculata cv. Sui Qing Dou Jiao formed pink effective nodules with NGR234 and NGR Omega nopL Omega y4lO. Nodules induced by NGR Omega y4lO were first pink but rapidly turned greenish (ineffective nodules), indicating premature senescence. An ultrastructural analysis of the nodules induced by NGR Omega y4lO revealed abnormal formation of enlarged infection droplets in ineffective nodules, whereas symbiosomes harboring a single bacteroid were frequently observed in effective nodules induced by NGR234 or NGR Omega nopL Omega y4lO. It is concluded that Y4lO is a symbiotic determinant involved in the differentiation of symbiosomes. Y4lO mitigated senescence-inducing effects caused by the T3 effector NopL, suggesting synergistic effects for Y4lO and NopL in nitrogen-fixing nodules.

Insertion of lattice strains into ordered LiNi0.5Mn1.5O4 spinel by mechanical stress: A comparison of perfect versus imperfect structures as a cathode for Li-ion batteries

NASA Astrophysics Data System (ADS)

Kozawa, Takahiro; Murakami, Takeshi; Naito, Makio

2016-07-01

The Ni-doped lithium manganese oxide, LiNi0.5Mn1.5O4, has received much attention as a cathode active material in high-energy lithium-ion batteries (LIBs). This active material has two different spinel structures depending on the ordering state of the Ni and Mn ions. The ordered LiNi0.5Mn1.5O4 spinel has an inferior cathode performance than the disordered phase because of its poor electronic conductivity. However, the ordered LiNi0.5Mn1.5O4 spinel possesses the potential advantage of avoiding dissolution of the Mn ion, which is an issue for the disordered spinel. The improvement of cathode performance is important for future applications. Here, we report a unique approach to improve the cathode performance of the ordered LiNi0.5Mn1.5O4 spinel. The mechanical treatment using an attrition-type mill successfully inserted lattice strains into the ordered LiNi0.5Mn1.5O4 spinel structure without a phase transformation to the disordered phase. The insertion of lattice strains by mechanical stresses provided an increased discharge capacity and a decreased charge transfer resistance. This limited crystal structure modification improved the cathode performance. The present work has the potential for application of the mechanically treated ordered LiNi0.5Mn1.5O4 spinel as a cathode for high-energy LIBs.

Whole-genome sequence of Escherichia coli serotype O157:H7 strain B6914-ARS

USDA-ARS?s Scientific Manuscript database

Escherichia coli serotype O157:H7 strain B6914-MS1 is a Shiga toxin-deficient human fecal isolate obtained by the Centers for Disease Control and Prevention that has been used extensively in applied research studies. Here we report the genome sequence of strain B6914-ARS, a B6914-MS1 clone that has ...

Strain Dependent Electronic Structure and Band Offset Tuning at Heterointerfaces of ASnO3 (A=Ca, Sr, and Ba) and SrTiO3

PubMed Central

Baniecki, John D.; Yamazaki, Takashi; Ricinschi, Dan; Van Overmeere, Quentin; Aso, Hiroyuki; Miyata, Yusuke; Yamada, Hiroaki; Fujimura, Norifumi; Maran, Ronald; Anazawa, Toshihisa; Valanoor, Nagarajan; Imanaka, Yoshihiko

2017-01-01

The valence band (VB) electronic structure and VB alignments at heterointerfaces of strained epitaxial stannate ASnO3 (A=Ca, Sr, and Ba) thin films are characterized using in situ X-ray and ultraviolet photoelectron spectroscopies, with band gaps evaluated using spectroscopic ellipsometry. Scanning transmission electron microscopy with geometric phase analysis is used to resolve strain at atomic resolution. The VB electronic structure is strain state dependent in a manner that correlated with a directional change in Sn-O bond lengths with strain. However, VB offsets are found not to vary significantly with strain, which resulted in ascribing most of the difference in band alignment, due to a change in the band gaps with strain, to the conduction band edge. Our results reveal significant strain tuning of conduction band offsets using epitaxial buffer layers, with strain-induced offset differences as large as 0.6 eV possible for SrSnO3. Such large conduction band offset tunability through elastic strain control may provide a pathway to minimize the loss of charge confinement in 2-dimensional electron gases and enhance the performance of photoelectrochemical stannate-based devices. PMID:28195149

Strain effects on oxygen vacancy energetics in KTaO 3

DOE Office of Scientific and Technical Information (OSTI.GOV)

Xi, Jianqi; Xu, Haixuan; Zhang, Yanwen

Due to lattice mismatch between epitaxial films and substrates, in-plane strain fields are produced in the thin films, with accompanying structural distortions, and ion implantation can be used to controllably engineer the strain throughout the film. Because of the strain profile, local defect energetics are changed. In this study, the effects of in-plane strain fields on the formation and migration of oxygen vacancies in KTaO 3 are investigated using first-principles calculations. In particular, the doubly positive charged oxygen vacancy (V 2+O) is studied, which is considered to be the main charge state of the oxygen vacancy in KTaO 3. Wemore » find that the formation energies for oxygen vacancies are sensitive to in-plane strain and oxygen position. The local atomic configuration is identified, and strong relaxation of local defect structure is mainly responsible for the formation characteristics of these oxygen vacancies. Based on the computational results, formation-dependent site preferences for oxygen vacancies are expected to occur under epitaxial strain, which can result in orders of magnitude differences in equilibrium vacancy concentrations on different oxygen sites. In addition, all possible migration pathways, including intra- and inter-plane diffusions, are considered. In contrast to the strain-enhanced intra-plane diffusion, the diffusion in the direction normal to the strained plane is impeded under the epitaxial strain field. Lastly, these anisotropic diffusion processes can further enhance site preferences.« less

Strain effects on oxygen vacancy energetics in KTaO 3

DOE PAGES

Xi, Jianqi; Xu, Haixuan; Zhang, Yanwen; ...

2017-02-07

Due to lattice mismatch between epitaxial films and substrates, in-plane strain fields are produced in the thin films, with accompanying structural distortions, and ion implantation can be used to controllably engineer the strain throughout the film. Because of the strain profile, local defect energetics are changed. In this study, the effects of in-plane strain fields on the formation and migration of oxygen vacancies in KTaO 3 are investigated using first-principles calculations. In particular, the doubly positive charged oxygen vacancy (V 2+O) is studied, which is considered to be the main charge state of the oxygen vacancy in KTaO 3. Wemore » find that the formation energies for oxygen vacancies are sensitive to in-plane strain and oxygen position. The local atomic configuration is identified, and strong relaxation of local defect structure is mainly responsible for the formation characteristics of these oxygen vacancies. Based on the computational results, formation-dependent site preferences for oxygen vacancies are expected to occur under epitaxial strain, which can result in orders of magnitude differences in equilibrium vacancy concentrations on different oxygen sites. In addition, all possible migration pathways, including intra- and inter-plane diffusions, are considered. In contrast to the strain-enhanced intra-plane diffusion, the diffusion in the direction normal to the strained plane is impeded under the epitaxial strain field. Lastly, these anisotropic diffusion processes can further enhance site preferences.« less

Ferroelectricity emerging in strained (111)-textured ZrO{sub 2} thin films

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fan, Zhen, E-mail: a0082709@u.nus.edu, E-mail: msecj@nus.edu.sg; Deng, Jinyu; Liu, Ziyan

2016-01-04

(Anti-)ferroelectricity in complementary metal-oxide-semiconductor (CMOS)-compatible binary oxides have attracted considerable research interest recently. Here, we show that by using substrate-induced strain, the orthorhombic phase and the desired ferroelectricity could be achieved in ZrO{sub 2} thin films. Our theoretical analyses suggest that the strain imposed on the ZrO{sub 2} (111) film by the TiN/MgO (001) substrate would energetically favor the tetragonal (t) and orthorhombic (o) phases over the monoclinic (m) phase of ZrO{sub 2}, and the compressive strain along certain 〈11-2〉 directions may further stabilize the o-phase. Experimentally ZrO{sub 2} thin films are sputtered onto the MgO (001) substrates buffered bymore » epitaxial TiN layers. ZrO{sub 2} thin films exhibit t- and o-phases, which are highly (111)-textured and strained, as evidenced by X-ray diffraction and transmission electron microscopy. Both polarization-electric field (P-E) loops and corresponding current responses to voltage stimulations measured with appropriate applied fields reveal the ferroelectric sub-loop behavior of the ZrO{sub 2} films at certain thicknesses, confirming that the ferroelectric o-phase has been developed in the strained (111)-textured ZrO{sub 2} films. However, further increasing the applied field leads to the disappearance of ferroelectric hysteresis, the possible reasons of which are discussed.« less

Complete genome sequences of two atypical enteropathogenic Escherichia coli O145 environmental strains

USDA-ARS?s Scientific Manuscript database

Escherichia coli O145 strains RM14715 and RM14723 were isolated from wildlife feces near a leafy greens-growing region in Yuma, Arizona. Both strains carry a distinct genotype compared with the E. coli O145 strains isolated from Salinas Valley, California. Here we report complete genome sequences an...

48 CFR 1552.224-70 - Social security numbers of consultants and certain sole proprietors and Privacy Act statement.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 48 Federal Acquisition Regulations System 6 2011-10-01 2011-10-01 false Social security numbers of... CONTRACT CLAUSES Texts of Provisions and Clauses 1552.224-70 Social security numbers of consultants and... provision in all solicitations. Social Security Numbers of Consultants and Certain Sole Proprietors and...

Scanning the landscape of genome architecture of non-O1 and non-O139 Vibrio cholerae by whole genome mapping reveals extensive population genetic diversity.

PubMed

Chapman, Carol; Henry, Matthew; Bishop-Lilly, Kimberly A; Awosika, Joy; Briska, Adam; Ptashkin, Ryan N; Wagner, Trevor; Rajanna, Chythanya; Tsang, Hsinyi; Johnson, Shannon L; Mokashi, Vishwesh P; Chain, Patrick S G; Sozhamannan, Shanmuga

2015-01-01

Historically, cholera outbreaks have been linked to V. cholerae O1 serogroup strains or its derivatives of the O37 and O139 serogroups. A genomic study on the 2010 Haiti cholera outbreak strains highlighted the putative role of non O1/non-O139 V. cholerae in causing cholera and the lack of genomic sequences of such strains from around the world. Here we address these gaps by scanning a global collection of V. cholerae strains as a first step towards understanding the population genetic diversity and epidemic potential of non O1/non-O139 strains. Whole Genome Mapping (Optical Mapping) based bar coding produces a high resolution, ordered restriction map, depicting a complete view of the unique chromosomal architecture of an organism. To assess the genomic diversity of non-O1/non-O139 V. cholerae, we applied a Whole Genome Mapping strategy on a well-defined and geographically and temporally diverse strain collection, the Sakazaki serogroup type strains. Whole Genome Map data on 91 of the 206 serogroup type strains support the hypothesis that V. cholerae has an unprecedented genetic and genomic structural diversity. Interestingly, we discovered chromosomal fusions in two unusual strains that possess a single chromosome instead of the two chromosomes usually found in V. cholerae. We also found pervasive chromosomal rearrangements such as duplications and indels in many strains. The majority of Vibrio genome sequences currently in public databases are unfinished draft sequences. The Whole Genome Mapping approach presented here enables rapid screening of large strain collections to capture genomic complexities that would not have been otherwise revealed by unfinished draft genome sequencing and thus aids in assembling and finishing draft sequences of complex genomes. Furthermore, Whole Genome Mapping allows for prediction of novel V. cholerae non-O1/non-O139 strains that may have the potential to cause future cholera outbreaks.

Spontaneous ferroelectricity in strained low-temperature monoclinic Fe3O4: A first-principles study

NASA Astrophysics Data System (ADS)

Liu, Xiang; Mi, Wen-Bo

2018-04-01

As a single-phase multiferroic material, Fe3O4 exhibits spontaneous ferroelectric polarization below 38 K. However, the nature of the ferroelectricity in Fe3O4 and effect of external disturbances such as strain on it remains ambiguous. Here, the spontaneous ferroelectric polarization of low-temperature monoclinic Fe3O4 was investigated by first-principles calculations. The pseudo-centrosymmetric Fe B42-Fe B43 pair has a different valence state. The noncentrosymmetric charge distribution results in ferroelectric polarization. The initial ferroelectric polarization direction is in the - x and - z directions. The ferroelectricity along the y axis is limited owing to the symmetry of the Cc space group. Both the ionic displacement and charge separation at the Fe B42-Fe B43 pair are affected by strain, which further influences the spontaneous ferroelectric polarization of monoclinic Fe3O4. The ferroelectric polarization along the z axis exhibits an increase of 45.3% as the strain changes from 6% to -6%.

Symmetry of Highly-Strained BiFeO3 Films in the Ultrathin Regime

NASA Astrophysics Data System (ADS)

Yang, Yongsoo; Senabulya, Nancy; Clarke, Roy; Schlepütz, Christian M.; Beekman, Christianne; Siemons, Wolter; Christen, Hans M.

2014-03-01

At room temperature, highly-strained BiFeO3 (BFO) films grown on LaAlO3 substrates exhibit a monoclinic structure with a giant c/a ratio (~1.3) when the films are thicker than 4 nm. Their structural symmetry can be controlled by adjusting the temperature [Appl. Phys. Express 4, 095801 (2011), Adv. Mater. 25, 5561 (2013)], with a high-temperature tetragonal phase being observed. We report that a structural phase transition can also be achieved by controlling the film thickness: synchrotron x-ray diffraction data shows that the Bragg peak splitting associated with the monoclinic phase disappears as the film thickness decreases below 3 nm, indicating a tetragonal symmetry, but still maintaining the giant c/a ratio. Unlike a similar transition reported for moderately strained BFO grown on SrTiO3 [APL Mater. 1, 052102 (2013)], the half-order Bragg peaks indicate that this transition does not involve a significant change in the octahedral tilt pattern of the film. This suggests that the structural evolution of highly-strained BFO films should be understood in terms of the unique (non-octahedral) oxygen coordination of the Fe ion in this highly-strained BFO, not the corner-connectivity of the oxygen octahedra between the film and the substrate. Funding: U.S. Department of Energy, BES-MSED (U. Michigan: DE-FG02-06ER46273, and at ORNL). Measurements: 13-BMC, 33-IDD, 33-BMC of the Advanced Photon Source, ANL (DE-AC02-06CH11357).

Estimation of lattice strain in nanocrystalline RuO2 by Williamson-Hall and size-strain plot methods.

PubMed

Sivakami, R; Dhanuskodi, S; Karvembu, R

2016-01-05

RuO2 nanoparticles (RuO2 NPs) have been successfully synthesized by the hydrothermal method. Structure and the particle size have been determined by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM) and transmission electron microscopy (TEM). UV-Vis spectra reveal that the optical band gap of RuO2 nanoparticles is red shifted from 3.95 to 3.55eV. BET measurements show a high specific surface area (SSA) of 118-133m(2)/g and pore diameter (10-25nm) has been estimated by Barret-Joyner-Halenda (BJH) method. The crystallite size and lattice strain in the samples have been investigated by Williamson-Hall (W-H) analysis assuming uniform deformation, deformation stress and deformation energy density, and the size-strain plot method. All other relevant physical parameters including stress, strain and energy density have been calculated. The average crystallite size and the lattice strain evaluated from XRD measurements are in good agreement with the results of TEM. Copyright © 2015 Elsevier B.V. All rights reserved.

Electron Raman scattering in a strained ZnO/MgZnO double quantum well

NASA Astrophysics Data System (ADS)

Mojab-abpardeh, M.; Karimi, M. J.

2018-02-01

In this work, the electron Raman scattering in a strained ZnO / MgZnO double quantum wells is studied. The energy eigenvalues and the wave functions are obtained using the transfer matrix method. The effects of Mg composition, well width and barrier width on the internal electric field in well and barrier layers are investigated. Then, the influences of these parameters on the differential cross-section of electron Raman scattering are studied. Results indicate that the position, magnitude and the number of the peaks depend on the Mg composition, well width and barrier width.

Antibodies Against the Current Influenza A(H1N1) Vaccine Strain Do Not Protect Some Individuals From Infection With Contemporary Circulating Influenza A(H1N1) Virus Strains.

PubMed

Petrie, Joshua G; Parkhouse, Kaela; Ohmit, Suzanne E; Malosh, Ryan E; Monto, Arnold S; Hensley, Scott E

2016-12-15

During the 2013-2014 influenza season, nearly all circulating 2009 pandemic influenza A(H1N1) virus (A[H1N1]pdm09) strains possessed an antigenically important mutation in hemagglutinin (K166Q). Here, we performed hemagglutination-inhibition (HAI) assays, using sera collected from 382 individuals prior to the 2013-2014 season, and we determined whether HAI titers were associated with protection from A(H1N1)pdm09 infection. Protection was associated with HAI titers against an A(H1N1)pdm09 strain possessing the K166Q mutation but not with HAI titers against the current A(H1N1)pdm09 vaccine strain, which lacks this mutation. These data indicate that contemporary A(H1N1)pdm09 strains are antigenically distinct from the current A(H1N1)pdm09 vaccine strain. © The Author 2016. Published by Oxford University Press for the Infectious Diseases Society of America. All rights reserved. For permissions, e-mail journals.permissions@oup.com.

Isolation and genetic characterization of an Actinobacillus pleuropneumoniae serovar K12:O3 strain.

PubMed

Ito, Hiroya; Matsumoto, Atsuko

2015-01-01

An atypical Actinobacillus pleuropneumoniae serovar 12 strain, termed QAS106, was isolated from a clinical case of porcine pleuropneumonia in Japan. An immunodiffusion (ID) test identified the strain as serovar 12. However, the ID test also demonstrated that strain QAS106 shared antigenic determinants with both the serovar 3 and 15 reference strains. Strain QAS106 was positive in the capsular serovar 12-specific polymerase chain reaction (PCR) assay, while the PCR toxin gene profiling and omlA PCR typing assays indicated that strain QAS106 was similar to serovar 3. The nucleotide sequence of the 16S ribosomal DNA (rDNA) of strain QAS106 was identical with that of serovars 3 and 12, but it showed 99.7% identity with that of serovar 15. Nucleotide sequence analysis revealed that genes involved in biosynthesis of the capsular polysaccharide (CPS) of strain QAS106 were identical to those of serovar 12 at the amino acid level. On the other hand, strain QAS106 would express putative proteins involved in the biosynthesis of lipopolysaccharide (LPS) O-polysaccharide (O-PS), the amino acid sequences of which were identical or nearly identical to those of serovars 3 and 15. In conclusion, strain QAS106 should be recognized as K12:O3, even though typical serovar 12 strains are K12:O12. The emergence of an atypical A. pleuropneumoniae serovar 12 strain expressing a rare combination of CPS and O-PS antigens would hamper precise serodiagnosis by the use of either CPS- or LPS-based serodiagnostic methodology alone. © 2014 The Author(s).

Bacteria meets influenza A virus: A bioluminescence mouse model of Escherichia coli O157:H7 following influenza A virus/Puerto Rico/8/34 (H1N1) strain infection.

PubMed

Wang, Zhongyi; Chi, Hang; Wang, Xiwen; Li, Wenliang; Li, Zhiping; Li, Jiaming; Fu, Yingying; Lu, Bing; Xia, Zhiping; Qian, Jun; Liu, Linna

2018-01-01

Objective To develop a bioluminescence-labelled bacterial infection model to monitor the colonization and clearance process of Escherichia coli O157:H7 in the lungs of mice following influenza A virus/Puerto Rico/8/34 (H1N1) strain (IAV/PR8) infection. Methods BALB/c mice were administered IAV/PR8 or 0.01 M phosphate-buffered saline (PBS; pH 7.4) intranasally 4 days prior to intranasal administration of 1 × 10 7 colony-forming units (CFU) of E. coli O157:H7-lux. Whole-body bioluminescent signals were monitored at 10 min, 4 h, 8 h, 12 h, 16 h and 24 h post-bacterial infection. Lung bioluminescent signals and bacterial load (CFU/g) were monitored at 4 h, 8 h, 12 h, 16 h and 24 h post-bacterial infection. Results Prior IAV/PR8 infection of mice resulted in a higher level of bacterial colonization and a lower rate of bacterial clearance from the lungs compared with mice treated with PBS. There were also consistent findings between the bioluminescence imaging and the CFU measurements in terms of identifying bacterial colonization and monitoring the clearance dynamics of E. coli O157:H7-lux in mouse lungs. Conclusion This novel bioluminescence-labelled bacterial infection model rapidly detected bacterial colonization of the lungs and monitored the clearance dynamics of E. coli O157:H7-lux following IAV/PR8 infection.

Structural determination of the acidic exopolysaccharide produced by a Pseudomonas sp. strain 1.15.

PubMed

Cescutti, P; Toffanin, R; Pollesello, P; Sutherland, I W

1999-01-31

Pseudomonas strain 1.15 was isolated from a freshwater biofilm and shown to produce considerable amounts of an acidic polysaccharide which was investigated by methylation analysis, NMR spectroscopy and ionspray mass spectrometry (ISMS). The polysaccharide was depolymerised by a bacteriophage-associated endoglucosidase and by autohydrolysis, and the resulting oligosaccharides were investigated by NMR spectroscopy and mass spectrometry. The resulting data showed that the parent repeating unit of the 1.15 exopolysaccharide (EPS) is a branched hexasaccharide. The main chain is constituted of the trisaccharide -->4)-alpha-L-Fucp-(1-->4)-alpha-L-Fucp-(1-->3)-beta-D-Glcp- (1--> and the side chain alpha-D-Galp-(1-->4)-beta-D-GlcAp-(1-->3)-alpha-D-Galp-(1-->is linked to O-3 of the first Fuc residue. The terminal non-reducing Gal carries a 1-carboxyethylidene acetal in the R configuration at the positions 4 and 6. Of the four different O-acetyl groups present in non-stoichiometric amounts, two were established to be on O-2 of the 3-linked Gal and on O-2 of the 4-linked Fuc.

Genetic characterization of Shiga toxin-producing Escherichia coli O26:H11 strains isolated from animal, food, and clinical samples.

PubMed

Krüger, Alejandra; Lucchesi, Paula M A; Sanso, A Mariel; Etcheverría, Analía I; Bustamante, Ana V; Burgán, Julia; Fernández, Luciana; Fernández, Daniel; Leotta, Gerardo; Friedrich, Alexander W; Padola, Nora L; Rossen, John W A

2015-01-01

The Shiga-toxin producing Escherichia coli (STEC) may cause serious illness in human. Here we analyze O26:H11 strains known to be among the most reported STEC strains causing human infections. Genetic characterization of strains isolated from animal, food, and clinical specimens in Argentina showed that most carried either stx 1a or stx 2a subtypes. Interestingly, stx 2a-positive O26:H11 rarely isolated from cattle in other countries showed to be an important proportion of O26:H11 strains circulating in cattle and food in our region. Seventeen percent of the isolates harbored more than one gene associated with antimicrobial resistance. In addition to stx, all strains contained the virulence genes eae-β, tir, efa, iha, espB, cif, espA, espF, espJ, nleA, nleB, nleC, and iss; and all except one contained ehxA, espP, and cba genes. On the other hand, toxB and espI genes were exclusively observed in stx 2-positive isolates, whereas katP was only found in stx 1a-positive isolates. Our results show that O26:H11 STEC strains circulating in Argentina, including those isolated from humans, cattle, and meat products, present a high pathogenic potential, and evidence that cattle can be a reservoir of O26:H11 strains harboring stx 2a.

Genetic characterization of Shiga toxin-producing Escherichia coli O26:H11 strains isolated from animal, food, and clinical samples

PubMed Central

Krüger, Alejandra; Lucchesi, Paula M. A.; Sanso, A. Mariel; Etcheverría, Analía I.; Bustamante, Ana V.; Burgán, Julia; Fernández, Luciana; Fernández, Daniel; Leotta, Gerardo; Friedrich, Alexander W.; Padola, Nora L.; Rossen, John W. A.

2015-01-01

The Shiga-toxin producing Escherichia coli (STEC) may cause serious illness in human. Here we analyze O26:H11 strains known to be among the most reported STEC strains causing human infections. Genetic characterization of strains isolated from animal, food, and clinical specimens in Argentina showed that most carried either stx1a or stx2a subtypes. Interestingly, stx2a-positive O26:H11 rarely isolated from cattle in other countries showed to be an important proportion of O26:H11 strains circulating in cattle and food in our region. Seventeen percent of the isolates harbored more than one gene associated with antimicrobial resistance. In addition to stx, all strains contained the virulence genes eae-β, tir, efa, iha, espB, cif, espA, espF, espJ, nleA, nleB, nleC, and iss; and all except one contained ehxA, espP, and cba genes. On the other hand, toxB and espI genes were exclusively observed in stx2-positive isolates, whereas katP was only found in stx1a-positive isolates. Our results show that O26:H11 STEC strains circulating in Argentina, including those isolated from humans, cattle, and meat products, present a high pathogenic potential, and evidence that cattle can be a reservoir of O26:H11 strains harboring stx2a. PMID:26539413

Influence of piezoelectric strain on the Raman spectra of BiFeO{sub 3} films deposited on PMN-PT substrates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Himcinschi, Cameliu, E-mail: himcinsc@physik.tu-freiberg.de; Talkenberger, Andreas; Kortus, Jens

2016-01-25

BiFeO{sub 3} epitaxial thin films were deposited on piezoelectric 0.72Pb(Mg{sub 1/3}Nb{sub 2/3})O{sub 3}-0.28PbTiO{sub 3} (PMN-PT) substrates with a conductive buffer layer (La{sub 0.7}Sr{sub 0.3}MnO{sub 3} or SrRuO{sub 3}) using pulsed laser deposition. The calibration of the strain values induced by the electric field applied on the piezoelectric PMN-PT substrates was realised using X-Ray diffraction measurements. The method of piezoelectrically induced strain allows one to directly obtain a quantitative correlation between the strain and the shift of the Raman-active phonons. This is a prerequisite for making Raman scattering a strong tool to probe the strain coupling in multiferroic nanostructures. Using themore » Poisson's number for BiFeO{sub 3}, one can determine the volume change induced by strain, and therefore the Grüneisen parameters for specific phonon modes.« less

Non-linear optical probing of strain-enabled ferroelectricity in CaTiO3 thin films

NASA Astrophysics Data System (ADS)

Vlahos, Eftihia; Brooks, Charles; Ecklund, Carl Johan; Biegalski, Mike; Rabe, Karin; Schlom, Darrell; Gopalan, Venkatraman

2010-03-01

First principles calculations predict CaTiO3, under tensile strain, to become ferroelectric with a spontaneous polarization of up to 0.5 C/m^2. Comparative second harmonic generation (SHG) studies of a series of strained CaTiO3 thin films were undertaken in order to determine their transition temperature and point group symmetry. The epitaxial strain ranged from -1.7% to 3.3%. Symmetry analysis of the SHG polar plots confirms that for the samples under tensile strain, the polarization is along the <110>p directions and the point group of the ferroelectric phase is mm2. SHG ``hysteresis'' loops were also obtained; these show clear switching. The experimental results are in excellent agreement with the first principles calculations predictions, and low temperature dielectric measurements that were performed on the same samples.

Whole-Genome Sequence of Escherichia coli Serotype O157:H7 Strain B6914-ARS.

PubMed

Uhlich, Gaylen A; Reichenberger, Erin R; Cottrell, Bryan J; Fratamico, Pina; Andreozzi, Elisa

2017-11-02

Escherichia coli serotype O157:H7 strain B6914-MS1 is an isolate from the Centers for Disease Control and Prevention that is missing both Shiga toxin genes and has been used extensively in applied research studies. Here we report the genome sequence of strain B6914-ARS, a B6914-MS1 clone that has unique biofilm properties.

Accessible switching of electronic defect type in SrTi O3 via biaxial strain

NASA Astrophysics Data System (ADS)

Chi, Yen-Ting; Youssef, Mostafa; Sun, Lixin; Van Vliet, Krystyn J.; Yildiz, Bilge

2018-05-01

Elastic strain is used widely to alter the mobility of free electronic carriers in semiconductors, but a predictive relationship between elastic lattice strain and the extent of charge localization of electronic defects is still underdeveloped. Here we considered SrTi O3 , a prototypical perovskite as a model functional oxide for thin film electronic devices and nonvolatile memories. We assessed the effects of biaxial strain on the stability of electronic defects at finite temperature by combining density functional theory (DFT) and quasiharmonic approximation (QHA) calculations. We constructed a predominance diagram for free electrons and small electron polarons in this material, as a function of biaxial strain and temperature. We found that biaxial tensile strain in SrTi O3 can stabilize the small polaron, leading to a thermally activated and slower electronic transport, consistent with prior experimental observations on SrTi O3 and distinct from our prior theoretical assessment of the response of SrTi O3 to hydrostatic stress. These findings also resolved apparent conflicts between prior atomistic simulations and conductivity experiments for biaxially strained SrTi O3 thin films. Our computational approach can be extended to other functional oxides, and for the case of SrTi O3 our findings provide concrete guidance for conditions under which strain engineering can shift the electronic defect type and concentration to modulate electronic transport in thin films.

Influence of quantum confinement and strain on orbital polarization of four-layer LaNiO 3 superlattices: A DFT+DMFT study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Park, Hyowon; Millis, Andrew J.; Marianetti, Chris A.

Atomically precise superlattices involving transition metal oxides provide a unique opportunity to engineer correlated electron physics using strain (modulated by choice of substate) and quantum confinement (controlled by layer thickness). We use the combination of density functional theory and dynamical mean field theory (DFT+DMFT) to study Ni E g d-orbital polarization in strained LaNiO 3/LaAlO 3 superlattices consisting of four layers of nominally metallic NiO 2 and four layers of insulating AlO 2 separated by LaO layers. The layer-resolved orbital polarization is calculated as a function of strain and analyzed in terms of structural, quantum confinement, and correlation effects. Wemore » determined that the effect of strain is from the dependence of the results on the Ni-O bondlength ratio and the octahedral rotation angles; quantum confinement is studied by comparison to bulk calculations with similar degrees of strain; correlation effects are inferred by varying interaction parameters within our DFT+DMFT calculations. The calculated dependence of orbital polarization on strain in superlattices is qualitatively consistent with recent X-ray absorption spectroscopy and resonant reflectometry data. But, interesting differences of detail are found between theory and experiment. Under tensile strain, the two inequivalent Ni ions display orbital polarization similar to that calculated for strained bulk LaNiO 3 and observed in experiment. Compressive strain produces a larger dependence of orbital polarization on Ni position and even the inner Ni layer exhibits orbital polarization different from that calculated for strained bulk LaNiO 3.« less

Influence of quantum confinement and strain on orbital polarization of four-layer LaNiO 3 superlattices: A DFT+DMFT study

DOE PAGES

Park, Hyowon; Millis, Andrew J.; Marianetti, Chris A.

2016-06-07

Atomically precise superlattices involving transition metal oxides provide a unique opportunity to engineer correlated electron physics using strain (modulated by choice of substate) and quantum confinement (controlled by layer thickness). We use the combination of density functional theory and dynamical mean field theory (DFT+DMFT) to study Ni E g d-orbital polarization in strained LaNiO 3/LaAlO 3 superlattices consisting of four layers of nominally metallic NiO 2 and four layers of insulating AlO 2 separated by LaO layers. The layer-resolved orbital polarization is calculated as a function of strain and analyzed in terms of structural, quantum confinement, and correlation effects. Wemore » determined that the effect of strain is from the dependence of the results on the Ni-O bondlength ratio and the octahedral rotation angles; quantum confinement is studied by comparison to bulk calculations with similar degrees of strain; correlation effects are inferred by varying interaction parameters within our DFT+DMFT calculations. The calculated dependence of orbital polarization on strain in superlattices is qualitatively consistent with recent X-ray absorption spectroscopy and resonant reflectometry data. But, interesting differences of detail are found between theory and experiment. Under tensile strain, the two inequivalent Ni ions display orbital polarization similar to that calculated for strained bulk LaNiO 3 and observed in experiment. Compressive strain produces a larger dependence of orbital polarization on Ni position and even the inner Ni layer exhibits orbital polarization different from that calculated for strained bulk LaNiO 3.« less

Role of phonon scattering by elastic strain field in thermoelectric Sr1-xYxTiO3-δ

NASA Astrophysics Data System (ADS)

Bhattacharya, S.; Mehdizadeh Dehkordi, A.; Tennakoon, S.; Adebisi, R.; Gladden, J. R.; Darroudi, T.; Alshareef, H. N.; Tritt, T. M.

2014-06-01

Perovskite-type SrTiO3-δ ceramics are multifunctional materials with significant potential as n-type thermoelectric (TE) materials. The electronic and thermal transport properties of spark plasma sintered polycrystalline Sr1-xYxTiO3-δ (x = 0.05, 0.075, 0.1) ceramics are systematically investigated from (15-800) K. The Sr0.9Y0.1TiO3-δ simultaneously exhibits a large Seebeck coefficient, α > -80 μV/K and moderately high electrical resistivity, ρ ˜ 0.8 mΩ-cm at a carrier concentration of ˜1021 cm-3 at 300 K resulting in a high TE power factor defined herein as (α2σT) ˜ 0.84 W/m-K at 760 K. Despite the similar atomic masses of Sr (87.6 g/mol) and Y (88.9 g/mol), the lattice thermal conductivity (κL) of Sr1-xYxTiO3-δ is significantly reduced with increased Y-doping, owing to the smaller ionic radii of Y3+ (˜1.23 Å, coordination number 12) compared to Sr2+ (˜1.44 Å, coordination number 12) ions. In order to understand the thermal conductivity reduction mechanism, the κL in the Sr1-xYxTiO3-δ series are phenomenologically modeled with a modified Callaway's equation from 30-600 K. Phonon scattering by elastic strain field due to ionic radii mismatch is found to be the prominent scattering mechanism in reducing κL of these materials. In addition, the effect of Y-doping on the elastic moduli of Sr1-xYxTiO3-δ (x = 0, 0.1) is investigated using resonant ultrasound spectroscopy, which exhibits an anomaly in x = 0.1 in the temperature range 300-600 K. As a result, the phonon mean free path is found to be further reduced in the Sr0.9Y0.1TiO3-δ compared to that of SrTiO3-δ, resulting in a considerably low thermal conductivity κ ˜ 2.7 W/m-K at 760 K. Finally, we report a thermoelectric figure of merit (ZT) ˜ 0.3 at 760 K in the Sr0.9Y0.1TiO3-δ, the highest ZT value reported in the Y-doped SrTiO3 ceramics thus far.

Electric-field-induced strain effects on the magnetization of a Pr 0.67Sr 0.33MnO 3 film

DOE PAGES

Zhang, B.; Sun, C. -J.; Lu, W.; ...

2015-05-26

The electric-field control of magnetic properties of Pr 0.67Sr 0.33MnO 3 (PSMO) film on piezoelectric Pb(Mg 1/3Nb 2/3)O 3-PbTiO 3 (PMNT) substrate was investigated. The piezoelectric response of the PMNT substrate to the electric field produced strain that was coupled to the PSMO film. The in-plane compressive (tensile) strain increased (decreased) the magnetization. The change of magnetic moment was associated with the Mn ions. First principle simulations showed that the strain-induced electronic redistribution of the two e g orbitals (3d z 2 and 3d x 2 -y 2) of Mn ions was responsible for the change of magnetic moment. Thismore » work demonstrates that the magnetoelectric effect in manganite/piezoelectric hetero-structures originates from the change in eg orbital occupancy of Mn ions induced by strain rather than the interfacial effect.« less

Scanning the landscape of genome architecture of non-O1 and non-O139 Vibrio cholerae by whole genome mapping reveals extensive population genetic diversity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chapman, Carol; Henry, Matthew; Bishop-Lilly, Kimberly A.

Historically, cholera outbreaks have been linked to V. cholerae O1 serogroup strains or its derivatives of the O37 and O139 serogroups. A genomic study on the 2010 Haiti cholera outbreak strains highlighted the putative role of non O1/non-O139 V. cholerae in causing cholera and the lack of genomic sequences of such strains from around the world. Here we address these gaps by scanning a global collection of V. cholerae strains as a first step towards understanding the population genetic diversity and epidemic potential of non O1/non-O139 strains. Whole Genome Mapping (Optical Mapping) based bar coding produces a high resolution, orderedmore » restriction map, depicting a complete view of the unique chromosomal architecture of an organism. To assess the genomic diversity of non-O1/non-O139 V. cholerae, we applied a Whole Genome Mapping strategy on a well-defined and geographically and temporally diverse strain collection, the Sakazaki serogroup type strains. Whole Genome Map data on 91 of the 206 serogroup type strains support the hypothesis that V. cholerae has an unprecedented genetic and genomic structural diversity. Interestingly, we discovered chromosomal fusions in two unusual strains that possess a single chromosome instead of the two chromosomes usually found in V. cholerae. We also found pervasive chromosomal rearrangements such as duplications and indels in many strains. The majority of Vibrio genome sequences currently in public databases are unfinished draft sequences. The Whole Genome Mapping approach presented here enables rapid screening of large strain collections to capture genomic complexities that would not have been otherwise revealed by unfinished draft genome sequencing and thus aids in assembling and finishing draft sequences of complex genomes. Furthermore, Whole Genome Mapping allows for prediction of novel V. cholerae non-O1/non-O139 strains that may have the potential to cause future cholera outbreaks.« less

Scanning the landscape of genome architecture of non-O1 and non-O139 Vibrio cholerae by whole genome mapping reveals extensive population genetic diversity

DOE PAGES

Chapman, Carol; Henry, Matthew; Bishop-Lilly, Kimberly A.; ...

2015-03-20

Historically, cholera outbreaks have been linked to V. cholerae O1 serogroup strains or its derivatives of the O37 and O139 serogroups. A genomic study on the 2010 Haiti cholera outbreak strains highlighted the putative role of non O1/non-O139 V. cholerae in causing cholera and the lack of genomic sequences of such strains from around the world. Here we address these gaps by scanning a global collection of V. cholerae strains as a first step towards understanding the population genetic diversity and epidemic potential of non O1/non-O139 strains. Whole Genome Mapping (Optical Mapping) based bar coding produces a high resolution, orderedmore » restriction map, depicting a complete view of the unique chromosomal architecture of an organism. To assess the genomic diversity of non-O1/non-O139 V. cholerae, we applied a Whole Genome Mapping strategy on a well-defined and geographically and temporally diverse strain collection, the Sakazaki serogroup type strains. Whole Genome Map data on 91 of the 206 serogroup type strains support the hypothesis that V. cholerae has an unprecedented genetic and genomic structural diversity. Interestingly, we discovered chromosomal fusions in two unusual strains that possess a single chromosome instead of the two chromosomes usually found in V. cholerae. We also found pervasive chromosomal rearrangements such as duplications and indels in many strains. The majority of Vibrio genome sequences currently in public databases are unfinished draft sequences. The Whole Genome Mapping approach presented here enables rapid screening of large strain collections to capture genomic complexities that would not have been otherwise revealed by unfinished draft genome sequencing and thus aids in assembling and finishing draft sequences of complex genomes. Furthermore, Whole Genome Mapping allows for prediction of novel V. cholerae non-O1/non-O139 strains that may have the potential to cause future cholera outbreaks.« less

Effect of orally-administered Lactobacillus plantarum LPLM-O1 strain in an immunosuppressed mouse model of urinary tract infection.

PubMed

de Arellano, A Ramírez; Sánchez, M; Vera, R; Jara, S; González, M; Castro, E

2012-03-01

Urinary tract infections (UTIs) affect both healthy and immunocompromised people, and they are treated with antibiotics. However, the high recurrence of UTIs obliges the use of natural mechanisms to regulate the normal microbiota through the use of e.g. lactic acid bacteria. In order to induce a UTI, 20 µl of the Escherichia coli (Ec-01) strain, in doses of 2.7×10(7) cfu/ml, was inoculated by way of the urethra in female Balb/c mice, all of them immunosuppressed with dexamethasone (10 mg/kg). Lactobacillus plantarum LPLM-O1 was used as a treatment, in daily doses of 1×10(7) cfu/ml, which were orally administered for seven days before the infection (preventive) or alongside the infection for seven days (curative). The oral administration of LPLM-O1 did not cause any adverse effects when used in an immunosuppressed animal model. It was observed that, when used as a preventive measure, LPLM-O1 induces a decrease in the infection, in the concentration of urinary leukocytes, and in the bacterial load. This study proposes the use of this lactic bacterium as a probiotic.

Strain control of giant magnetic anisotropy in metallic perovskite SrCoO3-δ thin films.

PubMed

Hu, Songbai; Cazorla, Claudio; Xiang, Feixiang; Ma, Hongfei; Wang, Jianyuan; Wang, Jianbo; Wang, Xiaolin; Ulrich, Clemens; Chen, Lang; Seidel, Jan

2018-06-08

Magnetic materials with large magnetic anisotropy are essential for workaday applications such as permanent magnets and magnetic data storage. There is widespread interest in finding efficient ways of controlling magnetic anisotropy, among which strain control has proven to be a very powerful technique. Here we demonstrate strain-mediated magnetic anisotropy in SrCoO3-δ thin film, a perovskite oxide that is metallic and adopts a cubic structure at δ ≤ 0.25. We find that the easy-magnetization axis in SrCoO3-δ can be rotated by 90º upon application of moderate epitaxial strains ranging from -1.2% to +1.8%. The magnetic anisotropy in compressive SrCoO3-δ thin films is giant as shown by magnetic hysteresis loops rendering an anisotropy energy density of ~106 erg/cm3. The local variance of magnetic force microscopy (MFM) upon temperature and magnetic field reveals that the evolution of magnetic domains in SCO thin film is strongly dependent on the magnetic anisotropy.

Strain induced ferromagnetism and large magnetoresistance of epitaxial La1.5Sr0.5CoMnO6 thin films

NASA Astrophysics Data System (ADS)

Krishna Murthy, J.; Jyotsna, G.; N, Nileena; Anil Kumar, P. S.

2017-08-01

In this study, the structural, magnetic, and magneto-transport properties of La1.5Sr0.5CoMnO6 (LSCMO) thin films deposited on a SrTiO3 (001) substrate were investigated. A normal θ/2θ x-ray diffraction, rocking curve, ϕ-scan, and reciprocal space mapping data showed that prepared LSCMO thin films are single phase and highly strained with epitaxial nature. Temperature vs. magnetization of LSCMO films exhibits strain-induced ferromagnetic ordering with TC ˜ 165 K. In contrast to the bulk samples, there was no exchange bias and canted type antiferromagnetic and spin glass behavior in films having thickness (t) ≤ 26 nm. Temperature dependent resistivity data were explained using Schnakenberg's model and the polaron hopping conduction process. The slope change in resistivity and magnetoresistance maximum (˜65%) around TC indicates the existence of a weak double exchange mechanism between the mixed valence states of transition metal ions. Suppression of spin dependent scattering with the magnetic field is attributed for the large negative magnetoresistance in LSCMO films.

The plasmid of Escherichia coli strain S88 (O45:K1:H7) that causes neonatal meningitis is closely related to avian pathogenic E. coli plasmids and is associated with high-level bacteremia in a neonatal rat meningitis model.

PubMed

Peigne, Chantal; Bidet, Philippe; Mahjoub-Messai, Farah; Plainvert, Céline; Barbe, Valérie; Médigue, Claudine; Frapy, Eric; Nassif, Xavier; Denamur, Erick; Bingen, Edouard; Bonacorsi, Stéphane

2009-06-01

A new Escherichia coli virulent clonal group, O45:K1, belonging to the highly virulent subgroup B2(1) was recently identified in France, where it accounts for one-third of E. coli neonatal meningitis cases. Here we describe the sequence, epidemiology and function of the large plasmid harbored by strain S88, which is representative of the O45:K1 clonal group. Plasmid pS88 is 133,853 bp long and contains 144 protein-coding genes. It harbors three different iron uptake systems (aerobactin, salmochelin, and the sitABCD genes) and other putative virulence genes (iss, etsABC, ompT(P), and hlyF). The pS88 sequence is composed of several gene blocks homologous to avian pathogenic E. coli plasmids pAPEC-O2-ColV and pAPEC-O1-ColBM. PCR amplification of 11 open reading frames scattered throughout the plasmid was used to investigate the distribution of pS88 and showed that a pS88-like plasmid is present in other meningitis clonal groups such as O18:K1, O1:K1, and O83:K1. A pS88-like plasmid was also found in avian pathogenic strains and human urosepsis strains belonging to subgroup B2(1). A variant of S88 cured of its plasmid displayed a marked loss of virulence relative to the wild-type strain in a neonatal rat model, with bacteremia more than 2 log CFU/ml lower. The salmochelin siderophore, a known meningovirulence factor, could not alone explain the plasmid's contribution to virulence, as a salmochelin mutant displayed only a minor fall in bacteremia (0.9 log CFU/ml). Thus, pS88 is a major virulence determinant related to avian pathogenic plasmids that has spread not only through meningitis clonal groups but also human urosepsis and avian pathogenic strains.

Interfacial strain effects on lithium diffusion pathways in the spinel solid electrolyte Li-doped MgAl2O4

NASA Astrophysics Data System (ADS)

O'Rourke, Conn; Morgan, Benjamin J.

2018-04-01

The (Li,Al)-codoped magnesium spinel (LixMg1 -2 xAl2 +xO4 ) is a solid lithium-ion electrolyte with potential use in all-solid-state lithium-ion batteries. The spinel structure means that interfaces with spinel electrodes, such as LiyMn2O4 and Li4 +3 zTi5O12 , may be lattice matched, with potentially low interfacial resistances. Small lattice parameter differences across a lattice-matched interface are unavoidable, causing residual epitaxial strain. This strain potentially modifies lithium diffusion near the electrolyte-electrode interface, contributing to interfacial resistance. Here, we report a density functional theory study of strain effects on lithium diffusion pathways for (Li,Al)-codoped magnesium spinel, for xLi=0.25 and xLi=0.5 . We have calculated diffusion profiles for the unstrained materials, and for isotropic and biaxial tensile strains of up to 6 % , corresponding to {100 } epitaxial interfaces with LiyMn2O4 and Li4 +3 zTi5O12 . We find that isotropic tensile strain reduces lithium diffusion barriers by as much as 0.32 eV , with typical barriers reduced by ˜0.1 eV. This effect is associated with increased volumes of transitional octahedral sites, and broadly follows qualitative changes in local electrostatic potentials. For biaxial (epitaxial) strain, which more closely approximates strain at a lattice-matched electrolyte-electrode interface, changes in octahedral site volumes and in lithium diffusion barriers are much smaller than under isotropic strain. Typical barriers are reduced by only ˜0.05 eV. Individual effects, however, depend on the pathway considered and the relative strain orientation. These results predict that isotropic strain strongly affects ionic conductivities in (Li,Al)-codoped magnesium spinel electrolytes, and that tensile strain is a potential route to enhanced lithium transport. For a lattice-matched interface with candidate spinel-structured electrodes, however, epitaxial strain has a small, but complex, effect on lithium

Towards a Molecular Definition of Enterohemorrhagic Escherichia coli (EHEC): Detection of Genes Located on O Island 57 as Markers To Distinguish EHEC from Closely Related Enteropathogenic E. coli Strains

PubMed Central

Delannoy, Sabine; Beutin, Lothar

2013-01-01

Among strains of Shiga-toxin (Stx) producing Escherichia coli (STEC), seven serogroups (O26, O45, O103, O111, O121, O145, and O157) are associated with severe clinical illness in humans. These strains are also called enterohemorrhagic E. coli (EHEC), and the development of methods for their reliable detection from food has been challenging thus far. PCR detection of major EHEC virulence genes stx1, stx2, eae, and O-serogroup-specific genes is useful but does not identify EHEC strains specifically. Searching for the presence of additional genes issued from E. coli O157:H7 genomic islands OI-122 and OI-71 increases the specificity but does not clearly discriminate EHEC from enteropathogenic E. coli (EPEC) strains. Here, we identified two putative genes, called Z2098 and Z2099, from the genomic island OI-57 that were closely associated with EHEC and their stx-negative derivative strains (87% for Z2098 and 91% for Z2099). Z2098 and Z2099 were rarely found in EPEC (10% for Z2098 and 12% for Z2099), STEC (2 and 15%), and apathogenic E. coli (1% each) strains. Our findings indicate that Z2098 and Z2099 are useful genetic markers for a more targeted diagnosis of typical EHEC and new emerging EHEC strains. PMID:23325824

Comparative genome analysis of VSP-II and SNPs reveals heterogenic variation in contemporary strains of Vibrio cholerae O1 isolated from cholera patients in Kolkata, India

PubMed Central

Sekizuka, Tsuyoshi; Mizuno, Tamaki; Takemura, Taichiro; Yamashiro, Tetsu; Chowdhury, Goutam; Pazhani, Gururaja P.; Mukhopadhyay, Asish K.; Ramamurthy, Thandavarayan; Miyoshi, Shin-ichi; Kuroda, Makoto; Shinoda, Sumio; Ohnishi, Makoto

2017-01-01

Cholera is an acute diarrheal disease and a major public health problem in many developing countries in Asia, Africa, and Latin America. Since the Bay of Bengal is considered the epicenter for the seventh cholera pandemic, it is important to understand the genetic dynamism of Vibrio cholerae from Kolkata, as a representative of the Bengal region. We analyzed whole genome sequence data of V. cholerae O1 isolated from cholera patients in Kolkata, India, from 2007 to 2014 and identified the heterogeneous genomic region in these strains. In addition, we carried out a phylogenetic analysis based on the whole genome single nucleotide polymorphisms to determine the genetic lineage of strains in Kolkata. This analysis revealed the heterogeneity of the Vibrio seventh pandemic island (VSP)-II in Kolkata strains. The ctxB genotype was also heterogeneous and was highly related to VSP-II types. In addition, phylogenetic analysis revealed the shifts in predominant strains in Kolkata. Two distinct lineages, 1 and 2, were found between 2007 and 2010. However, the proportion changed markedly in 2010 and lineage 2 strains were predominant thereafter. Lineage 2 can be divided into four sublineages, I, II, III and IV. The results of this study indicate that lineages 1 and 2-I were concurrently prevalent between 2007 and 2009, and lineage 2-III observed in 2010, followed by the predominance of lineage 2-IV in 2011 and continued until 2014. Our findings demonstrate that the epidemic of cholera in Kolkata was caused by several distinct strains that have been constantly changing within the genetic lineages of V. cholerae O1 in recent years. PMID:28192431

Comparative genome analysis of VSP-II and SNPs reveals heterogenic variation in contemporary strains of Vibrio cholerae O1 isolated from cholera patients in Kolkata, India.

PubMed

Imamura, Daisuke; Morita, Masatomo; Sekizuka, Tsuyoshi; Mizuno, Tamaki; Takemura, Taichiro; Yamashiro, Tetsu; Chowdhury, Goutam; Pazhani, Gururaja P; Mukhopadhyay, Asish K; Ramamurthy, Thandavarayan; Miyoshi, Shin-Ichi; Kuroda, Makoto; Shinoda, Sumio; Ohnishi, Makoto

2017-02-01

Cholera is an acute diarrheal disease and a major public health problem in many developing countries in Asia, Africa, and Latin America. Since the Bay of Bengal is considered the epicenter for the seventh cholera pandemic, it is important to understand the genetic dynamism of Vibrio cholerae from Kolkata, as a representative of the Bengal region. We analyzed whole genome sequence data of V. cholerae O1 isolated from cholera patients in Kolkata, India, from 2007 to 2014 and identified the heterogeneous genomic region in these strains. In addition, we carried out a phylogenetic analysis based on the whole genome single nucleotide polymorphisms to determine the genetic lineage of strains in Kolkata. This analysis revealed the heterogeneity of the Vibrio seventh pandemic island (VSP)-II in Kolkata strains. The ctxB genotype was also heterogeneous and was highly related to VSP-II types. In addition, phylogenetic analysis revealed the shifts in predominant strains in Kolkata. Two distinct lineages, 1 and 2, were found between 2007 and 2010. However, the proportion changed markedly in 2010 and lineage 2 strains were predominant thereafter. Lineage 2 can be divided into four sublineages, I, II, III and IV. The results of this study indicate that lineages 1 and 2-I were concurrently prevalent between 2007 and 2009, and lineage 2-III observed in 2010, followed by the predominance of lineage 2-IV in 2011 and continued until 2014. Our findings demonstrate that the epidemic of cholera in Kolkata was caused by several distinct strains that have been constantly changing within the genetic lineages of V. cholerae O1 in recent years.

Strain-sensitive spin-state ordering in thin films of perovskite LaCoO3

NASA Astrophysics Data System (ADS)

Fujioka, J.; Yamasaki, Y.; Doi, A.; Nakao, H.; Kumai, R.; Murakami, Y.; Nakamura, M.; Kawasaki, M.; Arima, T.; Tokura, Y.

2015-11-01

We have investigated the lattice distortion coupled to the Co 3 d -spin-state ordering in thin films of perovskite LaCoO3 with various epitaxial strains by measurements of the magnetization, x-ray diffraction, and optical spectra. In the system with tensile strain about 0.5%, a lattice distortion characterized by the modulation vector q =(1 /6 ,1 /6 ,1 /6 ) emerges at 40 K, followed by a ferromagnetic ordering at 24 K. Alternatively, in systems with tensile strain exceeding 1%, the lattice distortion characterized by q =(1 /4 ,1 /4 ,1 /4 ) emerges at 120 K or higher, and subsequently the ferromagnetic or ferrimagnetic ordering occurs around 90 K. The evolution of infrared phonon spectra and resonant x-ray scattering at the Co K edge suggests that the population change in the Co 3 d spin state causes the strain-induced switching of spin-state ordering as well as of magnetic ordering in this canonical spin-state crossover system.

Strain distribution of confined Ge/GeO2 core/shell nanoparticles engineered by growth environments

NASA Astrophysics Data System (ADS)

Wei, Wenyan; Yuan, Cailei; Luo, Xingfang; Yu, Ting; Wang, Gongping

2016-02-01

The strain distributions of Ge/GeO2 core/shell nanoparticles confined in different host matrix grown by surface oxidation are investigated. The simulated results by finite element method demonstrated that the strains of the Ge core and the GeO2 shell strongly depend on the growth environments of the nanoparticles. Moreover, it can be found that there is a transformation of the strain on Ge core from tensile to compressive strain during the growth of Ge/GeO2 core/shell nanoparticles. And, the transformation of the strain is closely related with the Young's modulus of surrounding materials of Ge/GeO2 core/shell nanoparticles.

Complete Genome Sequence of the Neonatal Meningitis-Causing Escherichia coli Strain NMEC O18

PubMed Central

Nicholson, Bryon A.; Wannemuehler, Yvonne M.; Logue, Catherine M.; Li, Ganwu

2016-01-01

Neonatal meningitis Escherichia coli (NMEC) is a common agent of neonatal bacterial meningitis, causing high neonatal mortality and neurologic sequelae in its victims. Here, we present the complete genome sequence of NMEC O18 (also known as NMEC 58), a highly virulent (O18ac:K1, ST416) strain. PMID:27811114

Influence of piezoelectric strain on the Raman spectra of BiFeO 3 films deposited on PMN-PT substrates

DOE PAGES

Himcinschi, Cameliu; Guo, Er -Jia; Talkenberger, Andreas; ...

2016-01-27

In this study, BiFeO 3 epitaxial thin films were deposited on piezoelectric 0.72Pb(Mg 1/3Nb 2/3)O 3-0.28PbTiO 3 (PMN-PT) substrates with a conductive buffer layer (La 0.7Sr 0.3MnO 3 or SrRuO 3) using pulsed laser deposition. The calibration of the strain values induced by the electric field applied on the piezoelectric PMN-PT substrates was realised using X-Ray diffraction measurements. The method of piezoelectrically induced strain allows to obtain a quantitative correlation between strain and the shift of the Raman-active phonons, ruling out the influence of extrinsic factors, such as growth conditions, crystalline quality of substrates, or film thickness. Using the Poissonmore » number for BiFeO 3 one can determine the volume change induced by strain, and therefore the Gr neisen parameters for specific phonon modes.« less

Pathogenicity Island O-122 in enteropathogenic Escherichia coli strains is associated with diarrhea severity in children from Lima Peru

PubMed Central

Mercado, Erik H.; Piscoche, Cristian; Contreras, Carmen; Durand, David; Riveros, Maribel; Ruiz, Joaquim; Ochoa, Theresa J.

2016-01-01

EPEC is an attaching and effacing diarrheal pathogen that carries a large pathogenicity island, locus for enterocyte effacement (LEE). Recently, the pathogenicity island PAI O-122 was described among non-LEE effectors and found to be associated with diarrhea among atypical EPEC strains. It is unknown if incomplete PAI O-122 could be associated with diarrhea duration and severity. To identify these virulence determinants we analyzed 379 EPEC strains isolated from Peruvian children. EPEC was diagnosed by PCR(eae+, stx−) and classified as typical(t-EPEC) or atypical(a-EPEC). To characterize PAI O-122 we amplified three modules by PCR: Module 1(pagC), Module 2(senA, nleB and nleE) and Module 3(lifA/efa-1). To characterize the large ORF lifA/efa-1 we amplified the regions known as efa-N, efa-M and efa-C. Clinical information was obtained from the cohort study. A total of 379 EPEC strains were able to analyze PAI O-122 genes, 128 (10.4%) EPEC strains were isolated from 1235 diarrhea episodes and 251(9.2%) from 2734 healthy controls. t-EPEC strains were isolated from 14.8% (19/128) of children with diarrhea and 25/251(10.0%) from healthy controls. The most frequent PAI O-122 genes were nleE(37.7%), senA(34.6%) and nleB(37.5%), with similar prevalence among diarrhea and control samples. However, lifA/efa-1 was more common among diarrhea cases than healthy control cases (30.5% vs. 21.1%, p<0.05). The presence of complete PAI O-122 was associated with diarrhea episodes of higher severity among single pathogen infection (33.3% vs. 1.8%, p<0.05) mainly due to the presence of a complete lifA/efa-1 gene. In summary, the gene lifA/efa-1 is significantly associated with diarrheal episodes of higher severity, suggesting to be an important virulent factor. PMID:27236730

Pathogenicity Island O-122 in enteropathogenic Escherichia coli strains is associated with diarrhea severity in children from Lima Peru.

PubMed

Mercado, Erik H; Piscoche, Cristian; Contreras, Carmen; Durand, David; Riveros, Maribel; Ruiz, Joaquim; Ochoa, Theresa J

2016-06-01

EPEC is an attaching and effacing diarrheal pathogen that carries a large pathogenicity island, locus for enterocyte effacement (LEE). Recently, the pathogenicity island PAI O-122 was described among non-LEE effectors and found to be associated with diarrhea among atypical EPEC strains. It is unknown if incomplete PAI O-122 could be associated with diarrhea duration and severity. To identify these virulence determinants we analyzed 379 EPEC strains isolated from Peruvian children. EPEC was diagnosed by PCR(eae+, stx-) and classified as typical(t-EPEC) or atypical(a-EPEC). To characterize PAI O-122 we amplified three modules by PCR: Module 1(pagC), Module 2(senA, nleB and nleE) and Module 3(lifA/efa-1). To characterize the large ORF lifA/efa-1 we amplified the regions known as efa-N, efa-M and efa-C. Clinical information was obtained from the cohort study. A total of 379 EPEC strains were able to analyze PAI O-122 genes, 128 (10.4%) EPEC strains were isolated from 1235 diarrhea episodes and 251(9.2%) from 2734 healthy controls. t-EPEC strains were isolated from 14.8% (19/128) of children with diarrhea and 25/251(10.0%) from healthy controls. The most frequent PAI O-122 genes were nleE(37.7%), senA(34.6%) and nleB(37.5%), with similar prevalence among diarrhea and control samples. However, lifA/efa-1 was more common among diarrhea cases than healthy control cases (30.5% vs. 21.1%, p<0.05). The presence of complete PAI O-122 was associated with diarrhea episodes of higher severity among single pathogen infection (33.3% vs. 1.8%, p<0.05) mainly due to the presence of a complete lifA/efa-1 gene. In summary, the gene lifA/efa-1 is significantly associated with diarrheal episodes of higher severity, suggesting to be an important virulent factor. Copyright © 2016 Elsevier GmbH. All rights reserved.

38 CFR 1.553 - Public reading rooms and discretionary disclosures.

Code of Federal Regulations, 2012 CFR

2012-07-01

... electronically at its FOIA home page on the Internet, which contains the records that the FOIA requires to be regularly made available for public inspection and copying. See § 1.552(a) for the pertinent Internet... home page on the Internet. See § 1.552(a) for the pertinent Internet address. If the requester does not...

38 CFR 1.553 - Public reading rooms and discretionary disclosures.

Code of Federal Regulations, 2014 CFR

2014-07-01

... electronically at its FOIA home page on the Internet, which contains the records that the FOIA requires to be regularly made available for public inspection and copying. See § 1.552(a) for the pertinent Internet... home page on the Internet. See § 1.552(a) for the pertinent Internet address. If the requester does not...

38 CFR 1.553 - Public reading rooms and discretionary disclosures.

Code of Federal Regulations, 2013 CFR

2013-07-01

... electronically at its FOIA home page on the Internet, which contains the records that the FOIA requires to be regularly made available for public inspection and copying. See § 1.552(a) for the pertinent Internet... home page on the Internet. See § 1.552(a) for the pertinent Internet address. If the requester does not...

Dielectric response and structure of in-plane tensile strained BaTiO3 thin films grown on the LaNiO3 buffered Si substrate

NASA Astrophysics Data System (ADS)

Qiao, Liang; Bi, Xiaofang

2008-02-01

Highly (001)-textured BaTiO3 films were grown epitaxially on the LaNiO3 buffered Si substrate. A strong in-plane tensile strain has been revealed by using x-ray diffraction and high resolution transmission electron microscopy. The BaTiO3 film has exhibited a small remnant polarization, indicating the presence of ca1/ca2/ca1/ca2 polydomain state in the film. Temperature dependent dielectric permittivity has demonstrated that two phase transitions occurred at respective temperatures of 170 and 30°C. The result was discussed in detail based on the misfit strain-temperature phase diagrams theory.

Anisotropic strain relaxation in (Ba0.6Sr0.4)TiO3 epitaxial thin films

NASA Astrophysics Data System (ADS)

Simon, W. K.; Akdogan, E. K.; Safari, A.

2005-05-01

We have studied the evolution of anisotropic epitaxial strains in ⟨110⟩-oriented (Ba0.60Sr0.40)TiO3 paraelectric (m3m) thin films grown on orthorhombic (mm2) ⟨100⟩-oriented NdGaO3 by high-resolution x-ray diffractometry. All the six independent components of the three-dimensional strain tensor were measured in films with 25-1200-nm thickness, from which the principal stresses and strains were obtained. Pole figure analysis indicated that the epitaxial relations are [001]m3m‖[001]mm2 and [1¯10]m3m‖[010]mm2 in the plane of the film, and [110]m3m‖[100]mm2 along the growth direction. The dislocation system responsible for strain relief along [001] has been determined to be ∣b ∣(001)=3/4∣b∣. Strain relief along the [1¯10] direction, on the other hand, has been determined to be due to a coupled mechanism given by ∣b∣(1¯10)=∣b∣ and ∣b∣(1¯10)=√3 /4∣b∣. Critical thicknesses, as determined from nonlinear regression using the Matthews-Blakeslee equation, for misfit dislocation formation along [001] and [1¯10] direction were found to be 5 and 7 nm, respectively. The residual strain energy density was calculated as ˜2.9×106J/m3 at 25 nm, which was found to relax an order of magnitude by 200 nm. At 200 nm, the linear dislocation density along [001] and [1¯10] are ˜6.5×105 and ˜6×105cm-1, respectively. For films thicker than 600 nm, additional strain relief occurred through surface undulations, indicating that this secondary strain-relief mechanism is a volume effect that sets in upon cooling from the growth temperature.

Strain control of oxygen kinetics in the Ruddlesden-Popper oxide La 1.85Sr 0.15CuO 4

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meyer, Tricia L.; Jacobs, Ryan; Lee, Dongkyu

Oxygen defect control has long been considered an important route to functionalizing complex oxide films. However, the nature of oxygen defects in thin films is often not investigated beyond basic redox chemistry. One of the model examples for oxygen-defect studies is the layered Ruddlesden–Popper phase La 2-xSr x CuO 4-δ (LSCO), in which the superconducting transition temperature is highly sensitive to epitaxial strain. However, previous observations of strain-superconductivity coupling in LSCO thin films were mainly understood in terms of elastic contributions to mechanical buckling, with minimal consideration of kinetic or thermodynamic factors. Here, we report that the oxygen nonstoichiometry commonlymore » reported for strained cuprates is mediated by the strain-modified surface exchange kinetics, rather than reduced thermodynamic oxygen formation energies. Remarkably, tensile-strained LSCO shows nearly an order of magnitude faster oxygen exchange rate than a compressively strained film, providing a strategy for developing high-performance energy materials.« less

Strain control of oxygen kinetics in the Ruddlesden-Popper oxide La 1.85Sr 0.15CuO 4

DOE PAGES

Meyer, Tricia L.; Jacobs, Ryan; Lee, Dongkyu; ...

2018-01-08

Oxygen defect control has long been considered an important route to functionalizing complex oxide films. However, the nature of oxygen defects in thin films is often not investigated beyond basic redox chemistry. One of the model examples for oxygen-defect studies is the layered Ruddlesden–Popper phase La 2-xSr x CuO 4-δ (LSCO), in which the superconducting transition temperature is highly sensitive to epitaxial strain. However, previous observations of strain-superconductivity coupling in LSCO thin films were mainly understood in terms of elastic contributions to mechanical buckling, with minimal consideration of kinetic or thermodynamic factors. Here, we report that the oxygen nonstoichiometry commonlymore » reported for strained cuprates is mediated by the strain-modified surface exchange kinetics, rather than reduced thermodynamic oxygen formation energies. Remarkably, tensile-strained LSCO shows nearly an order of magnitude faster oxygen exchange rate than a compressively strained film, providing a strategy for developing high-performance energy materials.« less

Biased distribution of IS629 among strains in different lineages of enterohemorrhagic Escherichia coli serovar O157.

PubMed

Yokoyama, Eiji; Hashimoto, Ruiko; Etoh, Yoshiki; Ichihara, Sachiko; Horikawa, Kazumi; Uchimura, Masako

2011-01-01

The distribution of insertion sequence (IS) 629 among strains of enterohemorrhagic Escherichia coli serovar O157 (O157) was investigated and compared with the strain lineages defined by lineage specific polymorphism assay-6 (LSPA-6) to demonstrate the effectiveness of IS629 analysis for population genetics analysis. Using pulsed-field gel electrophoresis and variable-number tandem repeat typing, 140 strains producing both VT1 and VT2 and 98 strains producing only VT2 were selected from a total of 592 strains isolated from patients and asymptomatic carriers in Chiba Prefecture, Japan, during 2003-2008. By LSPA-6 analysis, six strains had atypical amplicon sizes in their Z5935 loci and five strains had atypical amplicon sizes in their arp-iclR intergenic regions. Sequence analyses of PCR amplified DNAs showed that five of the six loci used for LSPA-6 analysis had tandem repeats and the allele changes were due to changes in the number of tandem repeats. Subculturing and long-term incubation was found to have no detectable effect on the lineages defined by LSPA-6 analysis, demonstrating the robustness of LSPA-6 analysis. Minimum spanning tree analysis reconstruction revealed that strains in lineage I, I/II, and II clustered on separate branches, indicating that the distribution of IS629 was biased among O157 strains in different lineages. Strains with LSPA-6 codes 231111, 211113, and 211114 had atypical amplicon sizes and were clustered in lineage I/II branch, and strains with LSPA-6 codes 212114, 221123, 221223, 222123, 222224, 242123, 252123, and 242222 had atypical amplicon sizes and clustered in lineage II branches. Linkage disequilibrium was observed in strains in every lineage when the standardized index of association was calculated using IS629 distribution data. Therefore, the distribution analysis of IS629 may be effective for population genetics analysis of O157 due to the biased IS629 distribution among strains in the three O157 lineages. Copyright © 2010

Strain Gradient Modulated Exciton Evolution and Emission in ZnO Fibers.

PubMed

Wei, Bin; Ji, Yuan; Gauvin, Raynald; Zhang, Ze; Zou, Jin; Han, Xiaodong

2017-01-13

One-dimensional semiconductor can undergo large deformation including stretching and bending. This homogeneous strain and strain gradient are an easy and effective way to tune the light emission properties and the performance of piezo-phototronic devices. Here, we report that with large strain gradients from 2.1-3.5% μm -1 , free-exciton emission was intensified, and the free-exciton interaction (FXI) emission became a prominent FXI-band at the tensile side of the ZnO fiber. These led to an asymmetric variation in energy and intensity along the cross-section as well as a redshift of the total near-band-edge (NBE) emission. This evolution of the exciton emission was directly demonstrated using spatially resolved CL spectrometry combined with an in situ tensile-bending approach at liquid nitrogen temperature for individual fibers and nanowires. A distinctive mechanism of the evolution of exciton emission is proposed: the enhancement of the free-exciton-related emission is attributed to the aggregated free excitons and their interaction in the narrow bandgap in the presence of high bandgap gradients and a transverse piezoelectric field. These results might facilitate new approaches for energy conversion and sensing applications via strained nanowires and fibers.

Maximum imaging depth comparison in porcine vocal folds using 776-nm vs. 1552-nm excitation wavelengths

NASA Astrophysics Data System (ADS)

Yildirim, Murat; Ferhanoglu, Onur; Kobler, James B.; Zeitels, Steven M.; Ben-Yakar, Adela

2013-02-01

Vocal fold scarring is one of the major causes of voice disorders and may arise from overuse or post-surgical wound healing. One promising treatment utilizes the injection of soft biomaterials aimed at restoring viscoelasticity of the outermost vibratory layer of the vocal fold, superficial lamina propria (SLP). However, the density of the tissue and the required injection pressure impair proper localization of the injected biomaterial in SLP. To enhance treatment effectiveness, we are investigating a technique to image and ablate sub-epithelial planar voids in vocal folds using ultrafast laser pulses to better localize the injected biomaterial. It is challenging to optimize the excitation wavelength to perform imaging and ablation at depths suitable for clinical use. Here, we compare maximum imaging depth using two photon autofluorescence and second harmonic generation with third-harmonic generation imaging modalities for healthy porcine vocal folds. We used a home-built inverted nonlinear scanning microscope together with a high repetition rate (2 MHz) ultrafast fiber laser (Raydiance Inc.). We acquired both two-photon autofluorescence and second harmonic generation signals using 776 nm wavelength and third harmonic generation signals using 1552 nm excitation wavelength. We observed that maximum imaging depth with 776 nm wavelength is significantly improved from 114 μm to 205 μm when third harmonic generation is employed using 1552 nm wavelength, without any observable damage in the tissue.

Lattice distortion and strain relaxation in epitaxial thin films of multiferroic TbMnO3 probed by X-ray diffractometry and micro-Raman spectroscopy

NASA Astrophysics Data System (ADS)

Hu, Y.; Stender, D.; Medarde, M.; Lippert, T.; Wokaun, A.; Schneider, C. W.

2013-08-01

A detailed structural XRD analysis of (1 1 0)-oriented TbMnO3 thin films grown on (1 1 0)-YAlO3 substrates shows the co-existence of a strained and relaxed "sublayer" within the films due to strain relaxation during epitaxial growth by pulsed laser deposition. The substrate-film lattice mismatch yields a compressive strain anisotropy along the two in-plane directions, i.e. [1 -1 0] and [0 0 1] and a monoclinic distortion. A further manifestation of the growth-induced strain is the hardening of Raman active modes as a result of changed atomic motions along the [1 -1 0] and [0 0 1] directions.

Strain and Ni substitution induced ferromagnetism in LaCoO3 thin films

NASA Astrophysics Data System (ADS)

Kumar, Ashok; Kumar, Vinod; Kumar, Rajesh; Kumar, Ravi

2018-05-01

We have grown epitaxial strained films of LaCoO3 and LaCo0.7Ni0.3O3 on LaAlO3 (100) substrate via pulsed laser deposition. Superconducting quantum interference device magnetization measurements show that, unlike its bulk counterpart, the ground state of the strained LaCoO3 on LAO is ferromagnetic. The saturation magnetization has been found increase strongly from a value of 118 emu/cm3 to 350 emu/ cm3 for Ni substituted thin film. Present study reveals that strain can stabilize FM order in these thin films down to low temperature, which can further be tuned to higher saturation magnetization with the Ni substitution.

Strain effect on the magnetic and transport properties of LaCoO3 thin films

NASA Astrophysics Data System (ADS)

Li, Y.; Peng, S. J.; Wang, D. J.; Wu, K. M.; Wang, S. H.

2018-05-01

LaCoO3 (LCO) has attracted much attention due to the unique magnetic transition and spin transition of Co3+ ions. Epitaxial LCO film exhibits an unexpected ferromagnetism, in contrast to the non-magnetism of bulk LCO. An in-depth study on the property of strained LCO film is of great importance. We have fabricated 30 nm LCO films on various substrates and studied the magnetic and transport properties of films in different strain states (compressed strain for LCO/LaAlO3, tensile strain for LCO/(LaAlO3)0.3(Sr2TaAlO6)0.35, SrTiO3). The in-plane tensiled LCO films exhibit ferromagnetic ground state at 5K and magnetic transition with TC around 85K, while compressed LCO/LaAlO3 film has a negligibly small moment signal. Our results reveal that in-plane tensile strain and tetragonal distortion are much more favorable for stabilizing the FM order in LCO films.

Molecular and Phenotypic Characterization of Escherichia coli O26:H8 among Diarrheagenic E. coli O26 Strains Isolated in Brazil

PubMed Central

Piazza, Roxane M. F.; Delannoy, Sabine; Fach, Patrick; Saridakis, Halha O.; Pedroso, Margareth Z.; Rocha, Letícia B.; Gomes, Tânia A. T.; Vieira, Mônica A. M.; Beutin, Lothar

2013-01-01

Escherichia coli strains of serogroup O26 comprise two distinct groups of pathogens, characterized as enteropathogenic E. coli (EPEC) and enterohemorrhagic E. coli (EHEC). Among the several genes related to type III secretion system-secreted effector proteins, espK was found to be highly specific for EHEC O26:H11 and its stx-negative derivative strains isolated in European countries. E. coli O26 strains isolated in Brazil from infant diarrhea, foods, and the environment have consistently been shown to lack stx genes and are thus considered atypical EPEC. However, no further information related to their genetic background is known. Therefore, in this study, we aimed to discriminate and characterize these Brazilian O26 stx-negative strains by phenotypic, genetic, and biochemical approaches. Among 44 isolates confirmed to be O26 isolates, most displayed flagellar antigen H11 or H32. Out of the 13 nonmotile isolates, 2 tested positive for fliCH11, and 11 were fliCH8 positive. The identification of genetic markers showed that several O26:H11 and all O26:H8 strains tested positive for espK and could therefore be discriminated as EHEC derivatives. The presence of H8 among EHEC O26 and its stx-negative derivative isolates is described for the first time. The interaction of three isolates with polarized Caco-2 cells and with intestinal biopsy specimen fragments ex vivo confirmed the ability of the O26 strains analyzed to cause attaching-and-effacing (A/E) lesions. The O26:H32 strains, isolated mostly from meat, were considered nonvirulent. Knowledge of the virulence content of stx-negative O26 isolates within the same serotype helped to avoid misclassification of isolates, which certainly has important implications for public health surveillance. PMID:23974139

Implementation of ZnO/ZnMgO strained-layer superlattice for ZnO heteroepitaxial growth on sapphire

NASA Astrophysics Data System (ADS)

Petukhov, Vladimir; Bakin, Andrey; Tsiaoussis, Ioannis; Rothman, Johan; Ivanov, Sergey; Stoemenos, John; Waag, Andreas

2011-05-01

The main challenge in fabrication of ZnO-based devices is the absence of reliable p-type material. This is mostly caused by insufficient crystalline quality of the material and not well-enough-developed native point defect control of ZnO. At present high-quality ZnO wafers are still expensive and ZnO heteroepitaxial layers on sapphire are the most reasonable alternative to homoepitaxial layers. But it is still necessary to improve the crystalline quality of the heteroepitaxial layers. One of the approaches to reduce defect density in heteroepitaxial layers is to introduce a strained-layer superlattice (SL) that could stop dislocation propagation from the substrate-layer interface. In the present paper we have employed fifteen periods of a highly strained SL structure. The structure was grown on a conventional double buffer layer comprising of high-temperature MgO/low-temperature ZnO on sapphire. The influence of the SLs on the properties of the heteroepitaxial ZnO layers is investigated. Electrical measurements of the structure with SL revealed very high values of the carrier mobility up to 210 cm2/Vs at room temperature. Structural characterization of the obtained samples showed that the dislocation density in the following ZnO layer was not reduced. The high mobility signal appears to come from the SL structure or the SL/ZnO interface.

Hybrid & El Tor variant biotypes of Vibrio cholerae O1 in Thailand

PubMed Central

Na-Ubol, M.; Srimanote, P.; Chongsa-nguan, M.; Indrawattana, N.; Sookrung, N.; Tapchaisri, P.; Yamazaki, S.; Bodhidatta, L.; Eampokalap, B.; Kurazono, H.; Hayashi, H.; Nair, G.B.; Takeda, Y.; Chaicumpa, W.

2011-01-01

Background & objectives: El Tor Vibrio cholerae O1 carrying ctxBC trait, so-called El Tor variant that causes more severe symptoms than the prototype El Tor strain, first detected in Bangladesh was later shown to have emerged in India in 1992. Subsequently, similar V. cholerae strains were isolated in other countries in Asia and Africa. Thus, it was of interest to investigate the characteristics of V. cholerae O1 strains isolated chronologically (from 1986 to 2009) in Thailand. Methods: A total of 330 V. cholerae O1 Thailand strains from hospitalized patients with cholera isolated during 1986 to 2009 were subjected to conventional biotyping i.e., susceptibility to polymyxin B, chicken erythrocyte agglutination (CCA) and Voges-Proskauer (VP) test. The presence of ctxA, ctxB, zot, ace, toxR, tcpAC, tcpAE, hlyAC and hlyAE were examined by PCR. Mismatch amplification mutation assay (MAMA) - and conventional- PCRs were used for differentiating ctxB and rstR alleles. Results: All 330 strains carried the El Tor virulence gene signature. Among these, 266 strains were typical El Tor (resistant to 50 units of polymyxin B and positive for CCA and VP test) while 64 had mixed classical and El Tor phenotypes (hybrid biotype). Combined MAMA-PCR and the conventional biotyping methods revealed that 36 strains of 1986-1992 were either typical El Tor, hybrid, El Tor variant or unclassified biotype. The hybrid strains were present during 1986-2004. El Tor variant strains were found in 1992, the same year when the typical El Tor strains disappeared. All 294 strains of 1993-2009 carried ctxBC ; 237 were El Tor variant and 57 were hybrid. Interpretation & conclusions: In Thailand, hybrid V. cholerae O1 (mixed biotypes), was found since 1986. Circulating strains, however, are predominantly El Tor variant (El Tor biotype with ctxBC). PMID:21537091

Direct measurement of ferromagnetic ordering in biaxially strained LaCoO3 thin films

NASA Astrophysics Data System (ADS)

Klie, R. F.; Yuan, T.; Tanase, M.; Yang, G.; Ramasse, Q.

2010-02-01

LaCoO3 undergoes a transition from a nonmagnetic to a paramagnetic semiconductor at 80 K, associated with a spin-state transition of the Co3+ ions. It was proposed that the temperature of the spin-state transition depends strongly on the LaCoO3 lattice parameter, suggesting that strain can stabilize different spin states at different temperatures. By combining atomic-resolution Z-contrast imaging, electron diffraction, and angular-resolved electron energy-loss spectroscopy (EELS) with in situ cooling experiments, we show that epitaxially strained LaCoO3 (001) thin films grown on LaAlO3 (001) do not undergo a low temperature spin-state transition. Our EELS study explores the origins of the ferromagnetic ordering in strained LaCoO3 films.

Probing localized strain in solution-derived YB a2C u3O7 -δ nanocomposite thin films

NASA Astrophysics Data System (ADS)

Guzman, Roger; Gazquez, Jaume; Mundet, Bernat; Coll, Mariona; Obradors, Xavier; Puig, Teresa

2017-07-01

Enhanced pinning due to nanoscale strain is unique to the high-Tc cuprates, where pairing may be modified with lattice distortion. Therefore a comprehensive understanding of the defect landscape is required for a broad range of applications. However, determining the type and distribution of defects and their associated strain constitutes a critical task, and for this aim, real-space techniques for atomic resolution characterization are necessary. Here, we use scanning transmission electron microscopy (STEM) to study the atomic structure of individual defects of solution-derived YB a2C u3O7 (YBCO) nanocomposites, where the inclusion of incoherent secondary phase nanoparticles within the YBCO matrix dramatically increases the density of Y1B a2C u4O8 (Y124) intergrowths, the commonest defect in YBCO thin films. The formation of the Y124 is found to trigger a concatenation of strain-derived interactions with other defects and the concomitant nucleation of intrinsic defects, which weave a web of randomly distributed nanostrained regions that profoundly transform the vortex-pinning landscape of the YBCO nanocomposite thin films.

Strain-induced metal-insulator transitions in d1 perovskites within DFT+DMFT

NASA Astrophysics Data System (ADS)

Dymkowski, Krzysztof; Ederer, Claude

2014-03-01

We present results of combined density functional theory plus dynamical mean-field theory (DFT+DMFT) calculations, assessing the effect of epitaxial strain on the electronic properties of the Mott insulator LaTiO3 and the correlated metal SrVO3. In particular, we take into account the effect of strain on the collective tilts and rotations of the oxygen octahedra in the orthorhombically distorted Pbnm perovskite structure of LaTiO3. We find that LaTiO3 undergoes an insulator-to-metal transition under a compressive strain of about - 2 %, consistent with recent experimental observations. We show that this transition is driven mainly by strain-induced changes in the crystal-field splitting between the Ti t2 g orbitals, which in turn are related to changes in the octahedral tilt distortion. We compare this with the case of SrVO3, without octahedral tilts, where we find a metal-to-insulator transition under tensile epitaxial strain. Similar to LaTiO3, this metal-insulator transition is linked to the strain-induced change in the crystal-field splitting within the t2 g orbitals.

[Identification of resistance and susceptibility to cefotaxime in EHEC O121 strains isolated from an outbreak at two nurseries].

PubMed

Kikuchi, Koji; Ueno, Hiroyuki; Tomari, Kentaro; Kobori, Sumie; Kaetsu, Akihiko; Miyazaki, Motonobu

2014-07-01

A Shiga toxin 2 producing enterohemorrhagic Escherichia coli (EHEC) O121: H19 was isolated from a 2-year-old child who attending a nursery. An EHEC O121 outbreak in two nurseries (A, B), involving a total of 17 infected persons including 12 children, was revealed through contact investigation. The symptoms of all infected persons were almost all mild, and no one developed the hemolytic uremic syndrome. The combination use of desoxycholate-hydrogen sulfide-lactose (DHL) and CHROMagar STEC as selective isolation media was employed for efficient fecal examination. Nursery A and nursery B were combined as one group after the outbreak in nursery A was confirmed. As a result, EHEC O121 infected persons were also detected in children from nursery B. The 17 strains of EHEC O121 obtained from the total population showed almost the same pulsed-gel electrophoresis (PFGE) pattern, suggesting that these strains were very closely related. However, 13 of these 17 strains obtained from nursery A were susceptible to cefotaxime, whereas the remaining 4 strains obtained from nursery B showed cefotaxime resistance. A cefotaxime resistant Escherichia coli (E. coli) O86 strain was isolated in the stool specimen from a child who had been infected with the cefotaxime resistant EHEC O121. Both the cefotaxime resistant EHEC O121 and E. coli O86 had the same drug resistant gene (bla(CTX-M-1) group). The child was the index case of these 4 later cases and had received no antibiotics therapy prior to the laboratory examination. These findings suggested the possibility that an EHEC O121 strain had acquired a drug resistant gene from E. coli O86 in the digestive tract of the child.

Catabolism and Detoxification of 1-Aminoalkylphosphonic Acids: N-Acetylation by the phnO Gene Product

PubMed Central

Hove-Jensen, Bjarne; McSorley, Fern R.; Zechel, David L.

2012-01-01

In Escherichia coli uptake and catabolism of organophosphonates are governed by the phnCDEFGHIJKLMNOP operon. The phnO cistron is shown to encode aminoalkylphosphonate N-acetyltransferase, which utilizes acetylcoenzyme A as acetyl donor and aminomethylphosphonate, (S)- and (R)-1-aminoethylphosphonate, 2-aminoethyl- and 3-aminopropylphosphonate as acetyl acceptors. Aminomethylphosphonate, (S)-1-aminoethylphosphonate, 2-aminoethyl- and 3-aminopropylphosphonate are used as phosphate source by E. coli phn+ strains. 2-Aminoethyl- or 3-aminopropylphosphonate but not aminomethylphosphonate or (S)-1-aminoethylphosphonate is used as phosphate source by phnO strains. Neither phn+ nor phnO strains can use (R)-1-aminoethylphosphonate as phosphate source. Utilization of aminomethylphosphonate or (S)-1-aminoethylphosphonate requires the expression of phnO. In the absence of phnO-expression (S)-1-aminoethylphosphonate is bacteriocidal and rescue of phnO strains requires the simultaneous addition of d-alanine and phosphate. An intermediate of the carbon-phosphorus lyase pathway, 5′-phospho-α-d-ribosyl 1′-(2-N-acetamidoethylphosphonate), a substrate for carbon-phosphorus lyase, was found to accumulate in cultures of a phnP mutant strain. The data show that the physiological role of N-acetylation by phnO-specified aminoalkylphosphonate N-acetyltransferase is to detoxify (S)-1-aminoethylphosphonate, an analog of d-alanine, and to prepare (S)-1-aminoethylphosphonate and aminomethylphosphonate for utilization of the phosphorus-containing moiety. PMID:23056305

Strain-enhanced tunneling magnetoresistance in MgO magnetic tunnel junctions

PubMed Central

Loong, Li Ming; Qiu, Xuepeng; Neo, Zhi Peng; Deorani, Praveen; Wu, Yang; Bhatia, Charanjit S.; Saeys, Mark; Yang, Hyunsoo

2014-01-01

While the effects of lattice mismatch-induced strain, mechanical strain, as well as the intrinsic strain of thin films are sometimes detrimental, resulting in mechanical deformation and failure, strain can also be usefully harnessed for applications such as data storage, transistors, solar cells, and strain gauges, among other things. Here, we demonstrate that quantum transport across magnetic tunnel junctions (MTJs) can be significantly affected by the introduction of controllable mechanical strain, achieving an enhancement factor of ~2 in the experimental tunneling magnetoresistance (TMR) ratio. We further correlate this strain-enhanced TMR with coherent spin tunneling through the MgO barrier. Moreover, the strain-enhanced TMR is analyzed using non-equilibrium Green's function (NEGF) quantum transport calculations. Our results help elucidate the TMR mechanism at the atomic level and can provide a new way to enhance, as well as tune, the quantum properties in nanoscale materials and devices. PMID:25266219