Core neuropathological abnormalities in progranulin-deficient mice are penetrant on multiple genetic backgrounds.

Science.gov (United States)

Petkau, T L; Hill, A; Leavitt, B R

2016-02-19

Loss-of-function mutations in the progranulin gene (GRN) are a common cause of familial frontotemporal lobar degeneration (FTLD). A high degree of heterogeneity in the age-of-onset, duration of disease, and clinical presentation of FTLD, even among families carrying the same GRN mutation, suggests that additional modifying genes may be important to pathogenesis. Progranulin-knockout mice display subtle behavioral abnormalities and progressive neuropathological changes, as well as altered dendritic morphology and synaptic deficits in the hippocampus. In this study we evaluated multiple neuropathological endpoints in aged progranulin knockout mice and their wild-type littermates on two different genetic backgrounds: C57Bl/6 and 129/SvImJ. We find that in most brain regions, both strains are susceptible to progranulin-mediated neuropathological phenotypes, including astrogliosis, microgliosis, and highly accelerated deposition of the aging pigment lipofuscin. Neuroinflammation due to progranulin deficiency is exaggerated in the B6 strain and present, but less pronounced, in the 129 strain. Differences between the strains in hippocampal neuron counts and neuronal morphology suggest a complex role for progranulin in the hippocampus. We conclude that core progranulin-mediated neurodegenerative phenotypes are penetrant on multiple inbred mouse strains, but that genetic background modulates progranulin's role in neuroinflammation and hippocampal biology. Copyright © 2015 IBRO. Published by Elsevier Ltd. All rights reserved.

Xylitol production by genetically modified industrial strain of Saccharomyces cerevisiae using glycerol as co-substrate.

Science.gov (United States)

Kogje, Anushree B; Ghosalkar, Anand

2017-06-01

Xylitol is commercially used in chewing gum and dental care products as a low calorie sweetener having medicinal properties. Industrial yeast strain of S. cerevisiae was genetically modified to overexpress an endogenous aldose reductase gene GRE3 and a xylose transporter gene SUT1 for the production of xylitol. The recombinant strain (XP-RTK) carried the expression cassettes of both the genes and the G418 resistance marker cassette KanMX integrated into the genome of S. cerevisiae. Short segments from the 5' and 3' delta regions of the Ty1 retrotransposons were used as homology regions for integration of the cassettes. Xylitol production by the industrial recombinant strain was evaluated using hemicellulosic hydrolysate of the corn cob with glucose as the cosubstrate. The recombinant strain XP-RTK showed significantly higher xylitol productivity (212 mg L -1  h -1 ) over the control strain XP (81 mg L -1  h -1 ). Glucose was successfully replaced by glycerol as a co-substrate for xylitol production by S. cerevisiae. Strain XP-RTK showed the highest xylitol productivity of 318.6 mg L -1  h -1 and titre of 47 g L -1 of xylitol at 12 g L -1 initial DCW using glycerol as cosubstrate. The amount of glycerol consumed per amount of xylitol produced (0.47 mol mol -1 ) was significantly lower than glucose (23.7 mol mol -1 ). Fermentation strategies such as cell recycle and use of the industrial nitrogen sources were demonstrated using hemicellulosic hydrolysate for xylitol production.

Production of functionalized polyhydroxyalkanoates by genetically modified Methylobacterium extorquens strains

Directory of Open Access Journals (Sweden)

Miguez Carlos B

2010-09-01

Full Text Available Abstract Background Methylotrophic (methanol-utilizing bacteria offer great potential as cell factories in the production of numerous products from biomass-derived methanol. Bio-methanol is essentially a non-food substrate, an advantage over sugar-utilizing cell factories. Low-value products as well as fine chemicals and advanced materials are envisageable from methanol. For example, several methylotrophic bacteria, including Methylobacterium extorquens, can produce large quantities of the biodegradable polyester polyhydroxybutyric acid (PHB, the best known polyhydroxyalkanoate (PHA. With the purpose of producing second-generation PHAs with increased value, we have explored the feasibility of using M. extorquens for producing functionalized PHAs containing C-C double bonds, thus, making them amenable to future chemical/biochemical modifications for high value applications. Results Our proprietary M. extorquens ATCC 55366 was found unable to yield functionalized PHAs when fed methanol and selected unsaturated carboxylic acids as secondary substrates. However, cloning of either the phaC1 or the phaC2 gene from P. fluorescens GK13, using an inducible and regulated expression system based on cumate as inducer (the cumate switch, yielded recombinant M. extorquens strains capable of incorporating modest quantities of C-C double bonds into PHA, starting from either C6= and/or C8=. The two recombinant strains gave poor results with C11=. The strain containing the phaC2 gene was better at using C8= and at incorporating C-C double bonds into PHA. Solvent fractioning indicated that the produced polymers were PHA blends that consequently originated from independent actions of the native and the recombinant PHA synthases. Conclusions This work constitutes an example of metabolic engineering applied to the construction of a methanol-utilizing bacterium capable of producing functionalized PHAs containing C-C double bonds. In this regard, the PhaC2 synthase

Microstructure and annealing behavior of a modified 9Cr−1Mo steel after dynamic plastic deformation to different strains

International Nuclear Information System (INIS)

Zhang, Z.B.; Mishin, O.V.; Tao, N.R.; Pantleon, W.

2015-01-01

The microstructure, hardness and tensile properties of a modified 9Cr−1Mo steel processed by dynamic plastic deformation (DPD) to different strains (0.5 and 2.3) have been investigated in the as-deformed and annealed conditions. It is found that significant structural refinement and a high level of strength can be achieved by DPD to a strain of 2.3, and that the microstructure at this strain contains a large fraction of high angle boundaries. The ductility of the DPD processed steel is however low. Considerable structural coarsening of the deformed microstructure without pronounced recrystallization takes place during annealing of the low-strain and high-strain samples for 1 h at 650 °C and 600 °C, respectively. Both coarsening and partial recrystallization occur in the high-strain sample during annealing at 650 °C for 1 h. For this sample, it is found that whereas coarsening alone results in a loss of strength with only a small gain in ductility, coarsening combined with pronounced partial recrystallization enables a combination of appreciably increased ductility and comparatively high strength

Strain-modified RKKY interaction in carbon nanotubes

DEFF Research Database (Denmark)

Gorman, P. D.; Duffy, J. M.; Power, Stephen R.

2015-01-01

been shown that the interaction range depends on the conformation of the magnetic dopants in both graphene and nanotubes. Here we examine the Ruderman-Kittel-Kasuya-Yosida (RKKY) interaction in carbon nanotubes in the presence of uniaxial strain for a range of different impurity configurations. We show......For low-dimensionalmetallic structures, such as nanotubes, the exchange coupling between localized magnetic dopants is predicted to decay slowly with separation. The long-range character of this interaction plays a significant role in determining the magnetic order of the system. It has previously...... that strain is capable of amplifying or attenuating the RKKY interaction, significantly increasing certain interaction ranges, and acting as a switch: effectively turning on or off the interaction. We argue that uniaxial strain can be employed to significantly manipulate magnetic interactions in carbon...

Strain effects on the electronic structure of ZnSnP{sub 2} via modified Becke–Johnson exchange potential

Energy Technology Data Exchange (ETDEWEB)

Xu, Ying, E-mail: yingxuy@126.com [School of Physics and Electronic Science, Hunan University of Science and Technology, Xiangtan 411201 (China); Ao, Zhi Min [Centre for Clean Energy Technology, School of Chemistry and Forensic Science, University of Technology Sydney, PO Box 123, Broadway, Sydney, NSW 2007 (Australia); Zou, Dai Feng; Nie, Guo Zheng; Sheng, Wei [School of Physics and Electronic Science, Hunan University of Science and Technology, Xiangtan 411201 (China); Yuan, Ding Wang [College of Materials Science and Engineering, Hunan University, ChangSha 410082 (China)

2015-02-20

ZnSnP{sub 2} is a promising photovoltaic absorber material with a direct band gap of 1.68 eV, further reducing the band gap of ZnSnP{sub 2} that can achieve higher photovoltaic conversion efficiency. To achieve this target, the influence of biaxial in-plane strain (±3%) on the band gap, hole effective mass and optical properties of ZnSnP{sub 2} were investigated by first-principles calculations via Modified Becke–Johnson exchange potential. The results indicate that the biaxial tensile strain can reduce the band gap of ZnSnP{sub 2} from 1.3 eV to 1.0 eV and enhance the absorption of visible light of c-axis direction, while the biaxial compress strain increases the band gap of ZnSnP{sub 2} slightly. This research provides an alternative approach to tune the band gap of ZnSnP{sub 2} by strains. The variation of the band gap under different strains is determined by the highest-energy valance band state, and it can be explained by the redistribution of electrons under different strain. - Highlights: • The influence of biaxial in-plane strain (±3%) on the band gap of ZnSnP{sub 2} were investigated by DFT calculations. • MBJ exchange potential can describe the band structure of ZnSnP{sub 2} quite well. • Tensile strain brings a substantial decrease of the band gap, while the compress strain has no evident effect. • The calculated visible light adsorption coefficient increases along c-axis direction under tensile strain.

EFSA CEF Panel (EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids), 2014. Scientific Opinion on lipase from a genetically modified strain of Aspergillus oryzae (strain NZYM-FL)

DEFF Research Database (Denmark)

Poulsen, Morten; Hallas-Møller, Torben; Binderup, Mona-Lise

The food enzyme considered in this opinion is a lipase (triacylglycerol lipase; EC 3.1.1.3) produced with a genetically modified strain of Aspergillus oryzae. The genetic modifications do not raise safety concern. The food enzyme contains neither the production organism nor recombinant DNA...

Mineralization of PCBs by the genetically modified strain Cupriavidus necator JMS34 and its application for bioremediation of PCBs in soil

Energy Technology Data Exchange (ETDEWEB)

Saavedra, Juan Matias; Acevedo, Francisca; Gonzalez, Myriam; Seeger, Michael [Universidad Tecnica Federico Santa Maria, Valparaiso (Chile). Lab. de Microbiologia Molecular y Biotecnologia

2010-07-15

Polychlorobiphenyls (PCBs) are classified as ''high-priority pollutants''. Diverse microorganisms are able to degrade PCBs. However, bacterial degradation of PCBs is generally incomplete, leading to the accumulation of chlorobenzoates (CBAs) as dead-end metabolites. To obtain a microorganism able to mineralize PCB congeners, the bph locus of Burkholderia xenovorans LB400, which encodes one of the most effective PCB degradation pathways, was incorporated into the genome of the CBA-degrading bacterium Cupriavidus necator JMP134-X3. The bph genes were transferred into strain JMP134-X3, using the mini-Tn5 transposon system and biparental mating. The genetically modified derivative, C. necator strain JMS34, had only one chromosomal insertion of bph locus, which was stable under nonselective conditions. This modified bacterium was able to grow on biphenyl, 3-CBA and 4-CBA, and degraded 3,5-CBA in the presence of m-toluate. The strain JMS34 mineralized 3-CB, 4-CB, 2,4{sup '}-CB, and 3,5-CB, without accumulation of CBAs. Bioaugmentation of PCB-polluted soils with C. necator strain JMS34 and with the native B. xenovorans LB400 was monitored. It is noteworthy that strain JMS34 degraded, in 1 week, 99% of 3-CB and 4-CB and approximately 80% of 2,4{sup '}-CB in nonsterile soil, as well as in sterile soil. Additionally, the bacterial count of strain JMS34 increased by almost two orders of magnitude in PCB-polluted nonsterile soil. In contrast, the presence of native microflora reduced the degradation of these PCBs by strain LB400 from 73% (sterile soil) to approximately 50% (nonsterile soil). This study contributes to the development of improved biocatalysts for remediation of PCB-contaminated environments. (orig.)

Canthaxanthin production with modified Mucor circinelloides strains.

Science.gov (United States)

Papp, Tamás; Csernetics, Arpád; Nagy, Gábor; Bencsik, Ottó; Iturriaga, Enrique A; Eslava, Arturo P; Vágvölgyi, Csaba

2013-06-01

Canthaxanthin is a natural diketo derivative of β-carotene primarily used by the food and feed industries. Mucor circinelloides is a β-carotene-accumulating zygomycete fungus and one of the model organisms to study the carotenoid biosynthesis in fungi. In this study, the β-carotene ketolase gene (crtW) of the marine bacterium Paracoccus sp. N81106 fused with fungal promoter and terminator regions was integrated into the M. circinelloides genome to construct stable canthaxanthin-producing strains. Different transformation methods including polyethylene glycol-mediated transformation with linear DNA fragments, restriction enzyme-mediated integration and Agrobacterium tumefaciens-mediated transformation were tested to integrate the crtW gene into the Mucor genome. Mitotic stability, site of integration and copy number of the transferred genes were analysed in the transformants, and several stable strains containing the crtW gene in high copy number were isolated. Carotenoid composition of selected transformants and effect of culturing conditions, such as temperature, carbon sources and application of certain additives in the culturing media, on their carotenoid content were analysed. Canthaxanthin-producing transformants were able to survive at higher growth temperature than the untransformed strain, maybe due to the effect of canthaxanthin on the membrane fluidity and integrity. With the application of glucose, trehalose, dihydroxyacetone and L-aspartic acid as sole carbon sources in minimal medium, the crtW-expressing M. circinelloides strain, MS12+pCA8lf/1, produced more than 200 μg/g (dry mass) of canthaxanthin.

Determination of Burst Pressure of API Steel Pipes using Stress Modified Critical Strain Model

International Nuclear Information System (INIS)

Alang, N A; Razak, N A; Sulaiman, A S

2012-01-01

This paper presents a technique which can be used to determine the burst pressure of defective steel pipes using non-linear finite element (FE) analysis. The technique uses stress modified critical strain (SMCS) failure criterion to study the effect of gouge defects on maximum working pressure of API X65 steel pipes. The procedures in determining the model parameters using 3-D, homogeneous isotropic elastic-plastic material model with large deformation finite element analyses from notched tensile bars were systematically discussed. The relationship between burst pressure and gouge depth was proposed. The burst pressure estimated then was compared to experimental data from the literature for validation showing overall good agreements.

Origin of the low-frequency internal friction background of gold

Science.gov (United States)

Baur, J.; Benoit, W.

1986-11-01

The internal friction (IF) background of gold is studied in the kHz frequency range. Systematic measurements of IF as a function of frequency, strain amplitude, and temperature show that the IF is due to the superposition of two contributions: the thermoelastic effect and a dislocation effect. The thermoelastic effect is responsible for the IF background observed when the strain amplitude tends to zero. It is the only contribution to the IF background which is strain amplitude independent. On the contrary, the dislocation effect contributes only to the strain amplitude-dependent IF background. This effect is proportional to the strain amplitude. In particular, it is zero when the strain amplitude tends to zero. Furthermore, the dislocation contribution is frequency independent. The experimental results show that the dislocation effect cannot be explained by a viscous damping of dislocation motion, but must be related to an hysteretic and athermal motion of dislocations.

The strains recommended for use in the bacterial reverse mutation test (OECD guideline 471) can be certified as non-genetically modified organisms.

Science.gov (United States)

Sugiyama, Kei-Ichi; Yamada, Masami; Awogi, Takumi; Hakura, Atsushi

2016-01-01

The bacterial reverse mutation test, commonly called Ames test, is used worldwide. In Japan, the genetically modified organisms (GMOs) are regulated under the Cartagena Domestic Law, and organisms obtained by self-cloning and/or natural occurrence would be exempted from the law case by case. The strains of Salmonella typhimurium and Escherichia coli recommended for use in the bacterial reverse mutation test (OECD guideline 471), have been considered as non-GMOs because they can be constructed by self-cloning or naturally occurring bacterial strains, or do not disturb the biological diversity. The present article explains the reasons why these tester strains should be classified as non-GMOs.

Modifying the Electronic Properties of Nano-Structures Using Strain

International Nuclear Information System (INIS)

Lamba, V K; Engles, D

2012-01-01

We used density-functional theory based Non equilibrium green function simulations to study the effects of strain and quantum confinement on the electronic properties of Germanium and Silicon NWs along the [110] direction, such as the energy gap and the effective masses of the electron and hole. The diameters of the NWs being studied in a range of 3-20 Å. On basis of our calculation we conclude that the Ge [110] NWs possess a direct band gap, while Si [110] NWs possess indirect band gap at nanoscale. The band gap is almost a linear function of strain when the diameter of Ge NWs D 15 Å; and for Si it is linear in behaviour. On doping silicon wire we found that the bandgap shows parabolic behaviour for change in strain. We also concluded that the band gap and the effective masses of charge carries (i.e. electron and hole) changes by applying the strain to the NWs. Our results suggested that strain can be used to tune the band structures of NWs, which may help in de sign of future nanoelectronic devices.

A modified straight leg raise test to differentiate between sural nerve pathology and Achilles tendinopathy. A cross-sectional cadaver study

NARCIS (Netherlands)

Coppieters, M.W.J.; Crooke, J.L.; Lawrenson, P.R.; Khoo, S.J.; Skulstad, T.; Bet-Or, Y.

2015-01-01

Background: A modified straight leg raise test for the sural nerve (SLRSURAL) has been proposed to assist in the differential diagnosis of sural nerve pathology in people with posterior calf or ankle pain, or lateral foot pain. The biomechanical rationale is that strain in the

Preparation for emergence of an Eastern European porcine reproductive and respiratory syndrome virus (PRRSV) strain in Western Europe: Immunization with modified live virus vaccines or a field strain confers partial protection.

Science.gov (United States)

Renson, P; Fablet, C; Le Dimna, M; Mahé, S; Touzain, F; Blanchard, Y; Paboeuf, F; Rose, N; Bourry, O

2017-05-01

The porcine reproductive and respiratory syndrome virus (PRRSV) causes huge economic losses for the swine industry worldwide. In the past several years, highly pathogenic strains that lead to even greater losses have emerged. For the Western European swine industry, one threat is the possible introduction of Eastern European PRRSV strains (example Lena genotype 1.3) which were shown to be more virulent than common Western resident strains under experimental conditions. To prepare for the possible emergence of this strain in Western Europe, we immunized piglets with a Western European PRRSV field strain (Finistere: Fini, genotype 1.1), a new genotype 1 commercial modified live virus (MLV) vaccine (MLV1) or a genotype 2 commercial MLV vaccine (MLV2) to evaluate and compare the level of protection that these strains conferred upon challenge with the Lena strain 4 weeks later. Results show that immunization with Fini, MLV1 or MLV2 strains shortened the Lena-induced hyperthermia. In the Fini group, a positive effect was also demonstrated in growth performance. The level of Lena viremia was reduced for all immunized groups (significantly so for Fini and MLV2). This reduction in Lena viremia was correlated with the level of Lena-specific IFNγ-secreting cells. In conclusion, we showed that a commercial MLV vaccine of genotype 1 or 2, as well as a field strain of genotype 1.1 may provide partial clinical and virological protection upon challenge with the Lena strain. The cross-protection induced by these immunizing strains was not related with the level of genetic similarity to the Lena strain. The slightly higher level of protection established with the field strain is attributed to a better cell-mediated immune response. Copyright © 2017 Elsevier B.V. All rights reserved.

Molecular characterization of an unauthorized genetically modified Bacillus subtilis production strain identified in a vitamin B2 feed additive.

Science.gov (United States)

Paracchini, Valentina; Petrillo, Mauro; Reiting, Ralf; Angers-Loustau, Alexandre; Wahler, Daniela; Stolz, Andrea; Schönig, Birgit; Matthies, Anastasia; Bendiek, Joachim; Meinel, Dominik M; Pecoraro, Sven; Busch, Ulrich; Patak, Alex; Kreysa, Joachim; Grohmann, Lutz

2017-09-01

Many food and feed additives result from fermentation of genetically modified (GM) microorganisms. For vitamin B2 (riboflavin), GM Bacillus subtilis production strains have been developed and are often used. The presence of neither the GM strain nor its recombinant DNA is allowed for fermentation products placed on the EU market as food or feed additive. A vitamin B 2 product (80% feed grade) imported from China was analysed. Viable B. subtilis cells were identified and DNAs of two bacterial isolates (LHL and LGL) were subjected to three whole genome sequencing (WGS) runs with different devices (MiSeq, 454 or HiSeq system). WGS data revealed the integration of a chloramphenicol resistance gene, the deletion of the endogenous riboflavin (rib) operon and presence of four putative plasmids harbouring rib operons. Event- and construct-specific real-time PCR methods for detection of the GM strain and its putative plasmids in food and feed products have been developed. Copyright © 2017 Elsevier Ltd. All rights reserved.

Characterization of the Metabolically Modified Heavy Metal-Resistant Cupriavidus metallidurans Strain MSR33 Generated for Mercury Bioremediation

Science.gov (United States)

Rojas, Luis A.; Yáñez, Carolina; González, Myriam; Lobos, Soledad; Smalla, Kornelia; Seeger, Michael

2011-01-01

Background Mercury-polluted environments are often contaminated with other heavy metals. Therefore, bacteria with resistance to several heavy metals may be useful for bioremediation. Cupriavidus metallidurans CH34 is a model heavy metal-resistant bacterium, but possesses a low resistance to mercury compounds. Methodology/Principal Findings To improve inorganic and organic mercury resistance of strain CH34, the IncP-1β plasmid pTP6 that provides novel merB, merG genes and additional other mer genes was introduced into the bacterium by biparental mating. The transconjugant Cupriavidus metallidurans strain MSR33 was genetically and biochemically characterized. Strain MSR33 maintained stably the plasmid pTP6 over 70 generations under non-selective conditions. The organomercurial lyase protein MerB and the mercuric reductase MerA of strain MSR33 were synthesized in presence of Hg2+. The minimum inhibitory concentrations (mM) for strain MSR33 were: Hg2+, 0.12 and CH3Hg+, 0.08. The addition of Hg2+ (0.04 mM) at exponential phase had not an effect on the growth rate of strain MSR33. In contrast, after Hg2+ addition at exponential phase the parental strain CH34 showed an immediate cessation of cell growth. During exposure to Hg2+ no effects in the morphology of MSR33 cells were observed, whereas CH34 cells exposed to Hg2+ showed a fuzzy outer membrane. Bioremediation with strain MSR33 of two mercury-contaminated aqueous solutions was evaluated. Hg2+ (0.10 and 0.15 mM) was completely volatilized by strain MSR33 from the polluted waters in presence of thioglycolate (5 mM) after 2 h. Conclusions/Significance A broad-spectrum mercury-resistant strain MSR33 was generated by incorporation of plasmid pTP6 that was directly isolated from the environment into C. metallidurans CH34. Strain MSR33 is capable to remove mercury from polluted waters. This is the first study to use an IncP-1β plasmid directly isolated from the environment, to generate a novel and stable bacterial strain

Characterization of the metabolically modified heavy metal-resistant Cupriavidus metallidurans strain MSR33 generated for mercury bioremediation.

Directory of Open Access Journals (Sweden)

Luis A Rojas

Full Text Available BACKGROUND: Mercury-polluted environments are often contaminated with other heavy metals. Therefore, bacteria with resistance to several heavy metals may be useful for bioremediation. Cupriavidus metallidurans CH34 is a model heavy metal-resistant bacterium, but possesses a low resistance to mercury compounds. METHODOLOGY/PRINCIPAL FINDINGS: To improve inorganic and organic mercury resistance of strain CH34, the IncP-1β plasmid pTP6 that provides novel merB, merG genes and additional other mer genes was introduced into the bacterium by biparental mating. The transconjugant Cupriavidus metallidurans strain MSR33 was genetically and biochemically characterized. Strain MSR33 maintained stably the plasmid pTP6 over 70 generations under non-selective conditions. The organomercurial lyase protein MerB and the mercuric reductase MerA of strain MSR33 were synthesized in presence of Hg(2+. The minimum inhibitory concentrations (mM for strain MSR33 were: Hg(2+, 0.12 and CH(3Hg(+, 0.08. The addition of Hg(2+ (0.04 mM at exponential phase had not an effect on the growth rate of strain MSR33. In contrast, after Hg(2+ addition at exponential phase the parental strain CH34 showed an immediate cessation of cell growth. During exposure to Hg(2+ no effects in the morphology of MSR33 cells were observed, whereas CH34 cells exposed to Hg(2+ showed a fuzzy outer membrane. Bioremediation with strain MSR33 of two mercury-contaminated aqueous solutions was evaluated. Hg(2+ (0.10 and 0.15 mM was completely volatilized by strain MSR33 from the polluted waters in presence of thioglycolate (5 mM after 2 h. CONCLUSIONS/SIGNIFICANCE: A broad-spectrum mercury-resistant strain MSR33 was generated by incorporation of plasmid pTP6 that was directly isolated from the environment into C. metallidurans CH34. Strain MSR33 is capable to remove mercury from polluted waters. This is the first study to use an IncP-1β plasmid directly isolated from the environment, to generate a novel

Is the association between high strain work and depressive symptoms modified by private life social support: a cohort study of 1,074 Danish employees?

Science.gov (United States)

Madsen, Ida E H; Jorgensen, Anette F B; Borritz, Marianne; Nielsen, Martin L; Rugulies, Reiner

2014-07-08

Previous studies have shown that psychosocial working conditions characterized by high psychological demands and low decision latitude (i.e., high strain work) are associated with increased risk of depressive symptoms. Little is known, however, concerning how this association may be modified by factors outside the working environment. This article examines the modifying role of private life social support in the relation between high strain work and the development of severe depressive symptoms. Data were questionnaire-based, collected from a cross-occupational sample of 1,074 Danish employees. At baseline, all participants were free of severe depressive symptoms, measured by the Mental Health Inventory. High strain work was defined by the combination of high psychological demands at work and low control, measured with multi-dimensional scales. Private life social support was operationalized as the number of life domains with confidants and dichotomized as low (0-1 domains) or high (2 or more domains). Using logistic regression we examined the risk of onset of severe depressive symptoms, adjusting for sex, age, occupational position, and prior depressive symptoms. Separately, neither high strain work nor low private life social support statistically significantly predicted depressive symptoms. However, participants with joint exposure to high strain work and low private life social support had an Odds ratio (OR) for severe depressive symptoms of 3.41 (95% CI: 1.36-8.58), compared to participants with no work strain and high private life social support. There was no increased risk for participants with high strain work and high private life social support (OR = 1.32, 95% CI: 0.65-2.68). The interaction term for departure from additivity was, however, not statistically significant (p = 0.18). Our findings suggest that high strain work may increase risk of depressive symptoms in individuals with low private life social support, although the effect-modification was

Genetic background influences age-related decline in visual and nonvisual retinal responses, circadian rhythms, and sleep☆

Science.gov (United States)

Banks, Gareth; Heise, Ines; Starbuck, Becky; Osborne, Tamzin; Wisby, Laura; Potter, Paul; Jackson, Ian J.; Foster, Russell G.; Peirson, Stuart N.; Nolan, Patrick M.

2015-01-01

The circadian system is entrained to the environmental light/dark cycle via retinal photoreceptors and regulates numerous aspects of physiology and behavior, including sleep. These processes are all key factors in healthy aging showing a gradual decline with age. Despite their importance, the exact mechanisms underlying this decline are yet to be fully understood. One of the most effective tools we have to understand the genetic factors underlying these processes are genetically inbred mouse strains. The most commonly used reference mouse strain is C57BL/6J, but recently, resources such as the International Knockout Mouse Consortium have started producing large numbers of mouse mutant lines on a pure genetic background, C57BL/6N. Considering the substantial genetic diversity between mouse strains we expect there to be phenotypic differences, including differential effects of aging, in these and other strains. Such differences need to be characterized not only to establish how different mouse strains may model the aging process but also to understand how genetic background might modify age-related phenotypes. To ascertain the effects of aging on sleep/wake behavior, circadian rhythms, and light input and whether these effects are mouse strain-dependent, we have screened C57BL/6J, C57BL/6N, C3H-HeH, and C3H-Pde6b+ mouse strains at 5 ages throughout their life span. Our data show that sleep, circadian, and light input parameters are all disrupted by the aging process. Moreover, we have cataloged a number of strain-specific aging effects, including the rate of cataract development, decline in the pupillary light response, and changes in sleep fragmentation and the proportion of time spent asleep. PMID:25179226

Genetic background influences age-related decline in visual and nonvisual retinal responses, circadian rhythms, and sleep.

Science.gov (United States)

Banks, Gareth; Heise, Ines; Starbuck, Becky; Osborne, Tamzin; Wisby, Laura; Potter, Paul; Jackson, Ian J; Foster, Russell G; Peirson, Stuart N; Nolan, Patrick M

2015-01-01

The circadian system is entrained to the environmental light/dark cycle via retinal photoreceptors and regulates numerous aspects of physiology and behavior, including sleep. These processes are all key factors in healthy aging showing a gradual decline with age. Despite their importance, the exact mechanisms underlying this decline are yet to be fully understood. One of the most effective tools we have to understand the genetic factors underlying these processes are genetically inbred mouse strains. The most commonly used reference mouse strain is C57BL/6J, but recently, resources such as the International Knockout Mouse Consortium have started producing large numbers of mouse mutant lines on a pure genetic background, C57BL/6N. Considering the substantial genetic diversity between mouse strains we expect there to be phenotypic differences, including differential effects of aging, in these and other strains. Such differences need to be characterized not only to establish how different mouse strains may model the aging process but also to understand how genetic background might modify age-related phenotypes. To ascertain the effects of aging on sleep/wake behavior, circadian rhythms, and light input and whether these effects are mouse strain-dependent, we have screened C57BL/6J, C57BL/6N, C3H-HeH, and C3H-Pde6b+ mouse strains at 5 ages throughout their life span. Our data show that sleep, circadian, and light input parameters are all disrupted by the aging process. Moreover, we have cataloged a number of strain-specific aging effects, including the rate of cataract development, decline in the pupillary light response, and changes in sleep fragmentation and the proportion of time spent asleep. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Effects of strain and age on hepatic gene expression profiles in murine models of HFE-associated hereditary hemochromatosis.

Science.gov (United States)

Lee, Seung-Min; Loguinov, Alexandre; Fleming, Robert E; Vulpe, Christopher D

2015-01-01

Hereditary hemochromatosis is an iron overload disorder most commonly caused by a defect in the HFE gene. While the genetic defect is highly prevalent, the majority of individuals do not develop clinically significant iron overload, suggesting the importance of genetic modifiers. Murine hfe knockout models have demonstrated that strain background has a strong effect on the severity of iron loading. We noted that hepatic iron loading in hfe-/- mice occurs primarily over the first postnatal weeks (loading phase) followed by a timeframe of relatively static iron concentrations (plateau phase). We thus evaluated the effects of background strain and of age on hepatic gene expression in Hfe knockout mice (hfe-/-). Hepatic gene expression profiles were examined using cDNA microarrays in 4- and 8-week-old hfe-/- and wild-type mice on two different genetic backgrounds, C57BL/6J (C57) and AKR/J (AKR). Genes differentially regulated in all hfe-/- mice groups, compared with wild-type mice, including those involved in cell survival, stress and damage responses and lipid metabolism. AKR strain-specific changes in lipid metabolism genes and C57 strain-specific changes in cell adhesion and extracellular matrix protein genes were detected in hfe-/- mice. Mouse strain and age are each significantly associated with hepatic gene expression profiles in hfe-/- mice. These affects may underlie or reflect differences in iron loading in these mice.

Strained Si/SiGe MOS transistor model

Directory of Open Access Journals (Sweden)

Tatjana Pešić-Brđanin

2009-06-01

Full Text Available In this paper we describe a new model of surfacechannel strained-Si/SiGe MOSFET based on the extension of non-quasi-static (NQS circuit model previously derived for bulk-Si devices. Basic equations of the NQS model have been modified to account for the new physical parameters of strained-Si and relaxed-SiGe layers. From the comparisons with measurements, it is shown that a modified NQS MOS including steady-state self heating can accurately predict DC characteristics of Strained Silicon MOSFETs.

Mimicking mechanical response of natural tissues. Strain hardening induced by transient reticulation in lactose-modified chitosan (chitlac).

Science.gov (United States)

Cok, Michela; Sacco, Pasquale; Porrelli, Davide; Travan, Andrea; Borgogna, Massimiliano; Marsich, Eleonora; Paoletti, Sergio; Donati, Ivan

2018-01-01

The effect of transient cross-links has been explored on a lactose-modified chitosan, which previously had shown interesting biological features. The presence of galactose side chains and of the polyol spacer resulted particularly appealing for the reticulation by borate ions. The interaction between chitlac and borax was investigated by means of 11 B NMR while rheology pointed to a marked non-linear behavior depending on the amount of borax added to the system. The presence of limited amount of cross-linking ion led to dilatant behavior when the steady flow curve was measured. In addition, strain stiffening was noticed on elastic response upon exceeding a critical stress, indicating a transient nature in the formation of the cross-links. The non-linear response of chitlac in the presence of borax compared surprisingly well with the one showed by proteins composing the natural ECM pointing at a possible role of mechanotransduction in the biological significance of the modified chitosan. Copyright © 2017 Elsevier B.V. All rights reserved.

Microstructure and annealing behavior of a modified 9Cr-1Mo steel after dynamic plastic deformation to different strains

DEFF Research Database (Denmark)

Zhang, Zhenbo; Mishin, Oleg; Tao, N.R.

2015-01-01

The microstructure, hardness and tensile properties of a modified 9Cr-1Mo steel processed by dynamic plastic deformation (DPD) to different strains (0.5 and 2.3) have been investigated in the as-deformed and annealed conditions. It is found that significant structural refinement and a high level...... in a loss of strength with only a small gain in ductility, coarsening combined with pronounced partial recrystallization enables a combination of appreciably increased ductility and comparatively high strength....

Characterization of fatty acid modifying enzyme activity in staphylococcal mastitis isolates and other bacteria

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Lu Thea

2012-06-01

Full Text Available Abstract Background Fatty acid modifying enzyme (FAME has been shown to modify free fatty acids to alleviate their bactericidal effect by esterifying fatty acids to cholesterol or alcohols. Although it has been shown in previous studies that FAME is required for Staphylococcus aureus survival in skin abscesses, FAME is poorly studied compared to other virulence factors. FAME activity had also been detected in coagulase-negative staphylococci (CNS. However, FAME activity was only surveyed after a bacterial culture was grown for 24 h. Therefore if FAME activity was earlier in the growth phase, it would not have been detected by the assay and those strains would have been labeled as FAME negative. Results Fifty CNS bovine mastitis isolates and several S. aureus, Escherichia coli, and Streptococcus uberis strains were assayed for FAME activity over 24 h. FAME activity was detected in 54% of CNS and 80% S. aureus strains surveyed but none in E. coli or S. uberis. While some CNS strains produced FAME activity comparable to the lab strain of S. aureus, the pattern of FAME activity varied among strains and across species of staphylococci. All CNS that produced FAME activity also exhibited lipase activity. Lipase activity relative to colony forming units of these CNS decreased over the 24 h growth period. No relationship was observed between somatic cell count in the milk and FAME activity in CNS. Conclusions Some staphylococcal species surveyed produced FAME activity, but E. coli and S. uberis strains did not. All FAME producing CNS exhibited lipase activity which may indicate that both these enzymes work in concert to alter fatty acids in the bacterial environment.

Maxwell-Chern-Simons theory for curved spacetime backgrounds

International Nuclear Information System (INIS)

Kant, E.; Klinkhamer, F.R.

2005-01-01

We consider a modified version of four-dimensional electrodynamics, which has a photonic Chern-Simons-like term with spacelike background vector in the action. Light propagation in curved spacetime backgrounds is discussed using the geometrical-optics approximation. The corresponding light path is modified, which allows for new effects. In a Schwarzschild background, for example, there now exist stable bounded orbits of light rays and the two polarization modes of light rays in unbounded orbits can have different gravitational redshifts

Modification of Salmonella Typhimurium motility by the probiotic yeast strain Saccharomyces boulardii.

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Rodolphe Pontier-Bres

Full Text Available BACKGROUND: Motility is an important component of Salmonella enterica serovar Typhimurium (ST pathogenesis allowing the bacteria to move into appropriate niches, across the mucus layer and invade the intestinal epithelium. In vitro, flagellum-associated motility is closely related to the invasive properties of ST. The probiotic yeast Saccharomyces boulardii BIOCODEX (S.b-B is widely prescribed for the prophylaxis and treatment of diarrheal diseases caused by bacteria or antibiotics. In case of Salmonella infection, S.b-B has been shown to decrease ST invasion of T84 colon cell line. The present study was designed to investigate the impact of S.b-B on ST motility. METHODOLOGY/PRINCIPAL FINDINGS: Experiments were performed on human colonic T84 cells infected by the Salmonella strain 1344 alone or in the presence of S.b-B. The motility of Salmonella was recorded by time-lapse video microscopy. Next, a manual tracking was performed to analyze bacteria dynamics (MTrackJ plugin, NIH image J software. This revealed that the speed of bacterial movement was modified in the presence of S.b-B. The median curvilinear velocity (CLV of Salmonella incubated alone with T84 decreased from 43.3 µm/sec to 31.2 µm/sec in the presence of S.b-B. Measurement of track linearity (TL showed similar trends: S.b-B decreased by 15% the number of bacteria with linear tract (LT and increased by 22% the number of bacteria with rotator tract (RT. Correlation between ST motility and invasion was further established by studying a non-motile flagella-deficient ST strain. Indeed this strain that moved with a CLV of 0.5 µm/sec, presented a majority of RT and a significant decrease in invasion properties. Importantly, we show that S.b-B modified the motility of the pathogenic strain SL1344 and significantly decreased invasion of T84 cells by this strain. CONCLUSIONS: This study reveals that S.b-B modifies Salmonella's motility and trajectory which may account for the modification

Modification of Salmonella Typhimurium Motility by the Probiotic Yeast Strain Saccharomyces boulardii

Science.gov (United States)

Pontier-Bres, Rodolphe; Prodon, François; Munro, Patrick; Rampal, Patrick; Lemichez, Emmanuel; Peyron, Jean François; Czerucka, Dorota

2012-01-01

Background Motility is an important component of Salmonella enterica serovar Typhimurium (ST) pathogenesis allowing the bacteria to move into appropriate niches, across the mucus layer and invade the intestinal epithelium. In vitro, flagellum-associated motility is closely related to the invasive properties of ST. The probiotic yeast Saccharomyces boulardii BIOCODEX (S.b-B) is widely prescribed for the prophylaxis and treatment of diarrheal diseases caused by bacteria or antibiotics. In case of Salmonella infection, S.b-B has been shown to decrease ST invasion of T84 colon cell line. The present study was designed to investigate the impact of S.b-B on ST motility. Methodology/Principal Findings Experiments were performed on human colonic T84 cells infected by the Salmonella strain 1344 alone or in the presence of S.b-B. The motility of Salmonella was recorded by time-lapse video microscopy. Next, a manual tracking was performed to analyze bacteria dynamics (MTrackJ plugin, NIH image J software). This revealed that the speed of bacterial movement was modified in the presence of S.b-B. The median curvilinear velocity (CLV) of Salmonella incubated alone with T84 decreased from 43.3 µm/sec to 31.2 µm/sec in the presence of S.b-B. Measurement of track linearity (TL) showed similar trends: S.b-B decreased by 15% the number of bacteria with linear tract (LT) and increased by 22% the number of bacteria with rotator tract (RT). Correlation between ST motility and invasion was further established by studying a non-motile flagella-deficient ST strain. Indeed this strain that moved with a CLV of 0.5 µm/sec, presented a majority of RT and a significant decrease in invasion properties. Importantly, we show that S.b-B modified the motility of the pathogenic strain SL1344 and significantly decreased invasion of T84 cells by this strain. Conclusions This study reveals that S.b-B modifies Salmonella's motility and trajectory which may account for the modification of Salmonella

Modification of γ-induced mutagenesis in Ames test-strains

International Nuclear Information System (INIS)

Basha, S.G.; Krasavin, E.A.; Kozubek, S.; Amirtaev, K.G.

1990-01-01

Glycerine and cysteamine protective effect on mutagenesis was studied in 3 strains of Salmonella typhimurium under γ-radiation. Glycerine modifying effect was shown to be not similar for various test-strains and depended on DNA injury nature. DNA complex injuries were shown to play significant role in mutagenesis of TA100 and TA102 strains. Absence of cysteamine modifying effect on γ-induced mutagenesis testified to cysteamine effect on enzyme balance. 20 refs.; 2 figs.; 1 tab

Mismatch repair genes Mlh1 and Mlh3 modify CAG instability in Huntington's disease mice: genome-wide and candidate approaches.

Science.gov (United States)

Pinto, Ricardo Mouro; Dragileva, Ella; Kirby, Andrew; Lloret, Alejandro; Lopez, Edith; St Claire, Jason; Panigrahi, Gagan B; Hou, Caixia; Holloway, Kim; Gillis, Tammy; Guide, Jolene R; Cohen, Paula E; Li, Guo-Min; Pearson, Christopher E; Daly, Mark J; Wheeler, Vanessa C

2013-10-01

The Huntington's disease gene (HTT) CAG repeat mutation undergoes somatic expansion that correlates with pathogenesis. Modifiers of somatic expansion may therefore provide routes for therapies targeting the underlying mutation, an approach that is likely applicable to other trinucleotide repeat diseases. Huntington's disease Hdh(Q111) mice exhibit higher levels of somatic HTT CAG expansion on a C57BL/6 genetic background (B6.Hdh(Q111) ) than on a 129 background (129.Hdh(Q111) ). Linkage mapping in (B6x129).Hdh(Q111) F2 intercross animals identified a single quantitative trait locus underlying the strain-specific difference in expansion in the striatum, implicating mismatch repair (MMR) gene Mlh1 as the most likely candidate modifier. Crossing B6.Hdh(Q111) mice onto an Mlh1 null background demonstrated that Mlh1 is essential for somatic CAG expansions and that it is an enhancer of nuclear huntingtin accumulation in striatal neurons. Hdh(Q111) somatic expansion was also abolished in mice deficient in the Mlh3 gene, implicating MutLγ (MLH1-MLH3) complex as a key driver of somatic expansion. Strikingly, Mlh1 and Mlh3 genes encoding MMR effector proteins were as critical to somatic expansion as Msh2 and Msh3 genes encoding DNA mismatch recognition complex MutSβ (MSH2-MSH3). The Mlh1 locus is highly polymorphic between B6 and 129 strains. While we were unable to detect any difference in base-base mismatch or short slipped-repeat repair activity between B6 and 129 MLH1 variants, repair efficiency was MLH1 dose-dependent. MLH1 mRNA and protein levels were significantly decreased in 129 mice compared to B6 mice, consistent with a dose-sensitive MLH1-dependent DNA repair mechanism underlying the somatic expansion difference between these strains. Together, these data identify Mlh1 and Mlh3 as novel critical genetic modifiers of HTT CAG instability, point to Mlh1 genetic variation as the likely source of the instability difference in B6 and 129 strains and suggest that MLH1

Mismatch repair genes Mlh1 and Mlh3 modify CAG instability in Huntington's disease mice: genome-wide and candidate approaches.

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Ricardo Mouro Pinto

2013-10-01

Full Text Available The Huntington's disease gene (HTT CAG repeat mutation undergoes somatic expansion that correlates with pathogenesis. Modifiers of somatic expansion may therefore provide routes for therapies targeting the underlying mutation, an approach that is likely applicable to other trinucleotide repeat diseases. Huntington's disease Hdh(Q111 mice exhibit higher levels of somatic HTT CAG expansion on a C57BL/6 genetic background (B6.Hdh(Q111 than on a 129 background (129.Hdh(Q111 . Linkage mapping in (B6x129.Hdh(Q111 F2 intercross animals identified a single quantitative trait locus underlying the strain-specific difference in expansion in the striatum, implicating mismatch repair (MMR gene Mlh1 as the most likely candidate modifier. Crossing B6.Hdh(Q111 mice onto an Mlh1 null background demonstrated that Mlh1 is essential for somatic CAG expansions and that it is an enhancer of nuclear huntingtin accumulation in striatal neurons. Hdh(Q111 somatic expansion was also abolished in mice deficient in the Mlh3 gene, implicating MutLγ (MLH1-MLH3 complex as a key driver of somatic expansion. Strikingly, Mlh1 and Mlh3 genes encoding MMR effector proteins were as critical to somatic expansion as Msh2 and Msh3 genes encoding DNA mismatch recognition complex MutSβ (MSH2-MSH3. The Mlh1 locus is highly polymorphic between B6 and 129 strains. While we were unable to detect any difference in base-base mismatch or short slipped-repeat repair activity between B6 and 129 MLH1 variants, repair efficiency was MLH1 dose-dependent. MLH1 mRNA and protein levels were significantly decreased in 129 mice compared to B6 mice, consistent with a dose-sensitive MLH1-dependent DNA repair mechanism underlying the somatic expansion difference between these strains. Together, these data identify Mlh1 and Mlh3 as novel critical genetic modifiers of HTT CAG instability, point to Mlh1 genetic variation as the likely source of the instability difference in B6 and 129 strains and suggest

Strain engineering of van der Waals heterostructures

NARCIS (Netherlands)

Vermeulen, Paul A.; Mulder, Jefta; Momand, Jamo; Kooi, Bart J.

2018-01-01

Modifying the strain state of solids allows control over a plethora of functional properties. The weak interlayer bonding in van der Waals (vdWaals) materials such as graphene, hBN, MoS2, and Bi2Te3 might seem to exclude strain engineering, since strain would immediately relax at the vdWaals

Genetic engineering of industrial Saccharomyces cerevisiae strains using a selection/counter-selection approach.

Science.gov (United States)

Kutyna, Dariusz R; Cordente, Antonio G; Varela, Cristian

2014-01-01

Gene modification of laboratory yeast strains is currently a very straightforward task thanks to the availability of the entire yeast genome sequence and the high frequency with which yeast can incorporate exogenous DNA into its genome. Unfortunately, laboratory strains do not perform well in industrial settings, indicating the need for strategies to modify industrial strains to enable strain development for industrial applications. Here we describe approaches we have used to genetically modify industrial strains used in winemaking.

Conductivity-Dependent Strain Response of Carbon Nanotube Treated Bacterial Nanocellulose

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S. Farjana

2013-01-01

Full Text Available This paper reports the strain sensitivity of flexible, electrically conductive, and nanostructured cellulose which was prepared by modification of bacterial cellulose with double-walled carbon nanotubes (DWCNTs and multiwalled carbon nanotubes (MWCNTs. The electrical conductivity depends on the modifying agent and its dispersion process. The conductivity of the samples obtained from bacterial cellulose (BNC pellicles modified with DWCNT was in the range from 0.034 S·cm−1 to 0.39 S·cm−1, and for BNC pellicles modified with MWCNTs it was from 0.12 S·cm−1 to 1.6 S·cm−1. The strain-induced electromechanical response, resistance versus strain, was monitored during the application of tensile force in order to study the sensitivity of the modified nanocellulose. A maximum gauge factor of 252 was found from the highest conductive sample treated by MWCNT. It has been observed that the sensitivity of the sample depends on the conductivity of the modified cellulose.

On lower order strain gradient plasticity theories

DEFF Research Database (Denmark)

Niordson, Christian Frithiof; Hutchinson, J. W.

2002-01-01

By way of numerical examples, this paper explores the nature of solutions to a class of strain gradient plasticity theories that employ conventional stresses, equilibrium equations and boundary conditions. Strain gradients come into play in these modified conventional theories only to alter...

Is there a role for modified probiotics as beneficial microbes: a systematic review of the literature.

Science.gov (United States)

Zorzela, L; Ardestani, S K; McFarland, L V; Vohra, S

2017-10-13

Our objective was to conduct a systematic review and meta-analysis for the use of modified (heat-killed or sonicated) probiotics for the efficacy and safety to prevent and treat various diseases. Recent clinical research has focused on living strains of probiotics, but use in high-risk patients and potential adverse reactions including bacteremia has focused interest on alternatives to the use of live probiotics. We searched MEDLINE/PubMed, Embase, Cochrane Central Register of Controlled Trials, CINAHL, Alt Health Watch, Web of Science, Scopus, PubMed, from inception to February 14, 2017 for randomised controlled trials involving modified probiotic strains. The primary outcome was efficacy to prevent or treat disease and the secondary outcome was incidence of adverse events. A total of 40 trials were included (n=3,913): 14 trials (15 arms with modified probiotics and 20 control arms) for the prevention of diseases and 26 trials (29 arms with modified probiotics and 32 control arms) for treatment of various diseases. Modified microbes were compared to either placebo (44%), or the same living probiotic strain (39%) or to only standard therapies (17%). Modified microbes were not significantly more or less effective than the living probiotic in 86% of the preventive trials and 69% of the treatment trials. Modified probiotic strains were significantly more effective in 15% of the treatment trials. Incidence rates of adverse events were similar for modified and living probiotics and other control groups, but many trials did not collect adequate safety data. Although several types of modified probiotics showed significant efficacy over living strains of probiotics, firm conclusions could not be reached due to the limited number of trials using the same type of modified microbe (strain, daily dose and duration) for a specific disease indication. Further research may illuminate other strains of modified probiotics that may have potential as clinical biotherapeutics.

Limitations of Hollomon and Ludwigson stress-strain relations in assessing the strain hardening parameters

International Nuclear Information System (INIS)

Samuel, K G

2006-01-01

It is shown that the deviation from the ideal Hollomon relation in describing the stress-strain behaviour is characteristic of all materials at low strains. The Ludwigson relation describing the deviation from the Hollomon relation at low strains is critically analysed and it is shown that the deviation at low strains is a consequence of some unknown 'plastic strain equivalent' present in the material. Stress strain curves obeying an ideal Hollomon relation as well as that of a structurally modified (prior cold worked) material were simulated and compared. The results show that the yield strength and the flow strength of a material at constant strain rate and temperature are dictated by the magnitude of the 'plastic strain equivalent' term. It is shown that this component need not necessarily mean a prior plastic strain present in the material due to prior cold work alone and that prior cold work strain will add to this. If this component is identified, the stress-strain behaviour can be adequately described by the Swift relation. It is shown that in both formalisms, the strain hardening index is a function of the yield strength of the material

Hand Gesture Recognition Using Modified 1$ and Background Subtraction Algorithms

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Hazem Khaled

2015-01-01

Full Text Available Computers and computerized machines have tremendously penetrated all aspects of our lives. This raises the importance of Human-Computer Interface (HCI. The common HCI techniques still rely on simple devices such as keyboard, mice, and joysticks, which are not enough to convoy the latest technology. Hand gesture has become one of the most important attractive alternatives to existing traditional HCI techniques. This paper proposes a new hand gesture detection system for Human-Computer Interaction using real-time video streaming. This is achieved by removing the background using average background algorithm and the 1$ algorithm for hand’s template matching. Then every hand gesture is translated to commands that can be used to control robot movements. The simulation results show that the proposed algorithm can achieve high detection rate and small recognition time under different light changes, scales, rotation, and background.

Monitoring the persistence of a genetically modified strain of the Azorhizobium caulinodans in the rhizosphere of Triticum aestivum L.

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Jan Jacek Slaski

2013-01-01

Full Text Available A protocol was developed to monitor persistence and spread of a genetically modified strain of the growth promoting diazotroph Azorhizobium caulinodans used to inoculate field grown wheat. The protocol was used to identify an endogluconase (egl overproducing strain of A. caulinodans isolated from inoculated soils. A detection limit of 2500 cfu g-1 and 108_1010cfu g-1 of soil was determined using the BIOLOG® fingerprinting method and PCR technique, respectively. Since none of the tested samples were positive for the bacteria or the Egl 1 gene construct, it was concluded that A. caulinodans ORS 571 pGV910-C1 did not persist or spread in any of the tested field locations. This result may be due to low soil temperatures and competition of indigenous microorganisms: environmental factors that were not favorable for the diazotroph to thrive in the test locations. The application of different inoculation methodologies, as well as the study of other rhizobial genera for the inoculation of wheat in further experiments, is strongly recommended. Key words: detection, diazotroph, endogluconase, ORS 571, wheat

Ductile failure analysis of defective API X65 pipes based on stress-modified fracture strain criterion

International Nuclear Information System (INIS)

Oh, Chang Kyun; Kim, Yun Jae; Baek, Jong Hyun; Kim, Young Pyo; Kim, Woo Sik

2006-01-01

A local failure criterion for the API X65 steel is applied to predict ductile failure of full-scale API X65 pipes with simulated corrosion and gouge defects under internal pressure. The local failure criterion is the stress-modified fracture strain for the API X65 steel as a function of the stress triaxiality (defined by the ratio of the hydrostatic stress to the effective stress). Based on detailed FE analyses with the proposed local failure criteria, burst pressures of defective pipes are estimated and compared with experimental data. The predicted burst pressures are in good agreement with experimental data. Noting that an assessment equation against the gouge defect is not yet available, parametric study is performed, from which a simple equation is proposed to predict burst pressure for API X65 pipes with gouge defects

The natural radiation background

International Nuclear Information System (INIS)

Duggleby, J.C.

1982-01-01

The components of the natural background radiation and their variations are described. Cosmic radiation is a major contributor to the external dose to the human body whilst naturally-occurring radionuclides of primordial and cosmogenic origin contribute to both the external and internal doses, with the primordial radionuclides being the major contributor in both cases. Man has continually modified the radiation dose to which he has been subjected. The two traditional methods of measuring background radiation, ionisation chamber measurements and scintillation counting, are looked at and the prospect of using thermoluminescent dosimetry is considered

An improved Armstrong-Frederick-Type Plasticity Model for Stable Cyclic Stress-Strain Responses Considering Nonproportional Hardening

Science.gov (United States)

Li, Jing; Zhang, Zhong-ping; Li, Chun-wang

2018-03-01

This paper modified an Armstrong-Frederick-type plasticity model for investigating the stable cyclic deformation behavior of metallic materials with different sensitivity to nonproportional loadings. In the modified model, the nonproportionality factor and nonproportional cyclic hardening coefficient coupled with the Jiang-Sehitoglu incremental plasticity model were used to estimate the stable stress-strain responses of the two materials (1045HR steel and 304 stainless steel) under various tension-torsion strain paths. A new equation was proposed to calculate the nonproportionality factor on the basis of the minimum normal strain range. Procedures to determine the minimum normal strain range were presented for general multiaxial loadings. Then, the modified model requires only the cyclic strain hardening exponent and cyclic strength coefficient to determine the material constants. It is convenient for predicting the stable stress-strain responses of materials in engineering application. Comparisons showed that the modified model can reflect the effect of nonproportional cyclic hardening well.

Strain-energy effects on dynamic fragmentation

International Nuclear Information System (INIS)

Glenn, L.A.; Chudnovsky, A.

1986-01-01

Grady's model of the dynamic fragmentation process, in which the average fragment size is determined by balancing the local kinetic energy and the surface energy, is modified to include the stored elastic (strain) energy. The revised model predicts that the strain energy should dominate for brittle materials, with low fracture toughness and high fracture-initiation stress. This conclusion is not borne out, however, by limited experimental data on brittle steels, even when the kinetic-energy density is small compared with the strain-energy density

Measuring systolic ankle and toe pressure using the strain gauge technique--a comparison study between mercury and indium-gallium strain gauges

DEFF Research Database (Denmark)

Broholm, Rikke; Wiinberg, Niels; Simonsen, Lene

2014-01-01

BACKGROUND: Measurement of the ankle and toe pressures are often performed using a plethysmograph, compression cuffs and a strain gauge. Usually, the strain gauge contains mercury but other alternatives exist. From 2014, the mercury-containing strain gauge will no longer be available in the Europ......BACKGROUND: Measurement of the ankle and toe pressures are often performed using a plethysmograph, compression cuffs and a strain gauge. Usually, the strain gauge contains mercury but other alternatives exist. From 2014, the mercury-containing strain gauge will no longer be available...... in the European Union. The aim of this study was to compare an indium-gallium strain gauge to the established mercury-containing strain gauge. METHODS: Consecutive patients referred to the Department of Clinical Physiology and Nuclear Medicine at Bispebjerg and Frederiksberg Hospitals for measurements of systolic...... ankle and toe pressures volunteered for the study. Ankle and toe pressures were measured twice with the mercury and the indium-gallium strain gauge in random order. Comparison of the correlation between the mean pressure using the mercury and the indium-gallium device and the difference between the two...

On lower order strain gradient plasticity theories

DEFF Research Database (Denmark)

Niordson, Christian Frithiof; Hutchinson, J. W.

2003-01-01

By way of numerical examples, this paper explores the nature of solutions to a class of strain gradient plasticity theories that employ conventional stresses, equilibrium equations and boundary conditions. Strain gradients come into play in these modified conventional theories only to alter...... the tangent moduli governing increments of stress and strain. It is shown that the modification is far from benign from a mathematical standpoint, changing the qualitative character of solutions and leading to a new type of localization that is at odds with what is expected from a strain gradient theory....... The findings raise questions about the physical acceptability of this class of strain gradient theories....

Improving yeast strains using recyclable integration cassettes, for the production of plant terpenoids

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Johnson Christopher B

2011-01-01

Full Text Available Abstract Background Terpenoids constitute a large family of natural products, attracting commercial interest for a variety of uses as flavours, fragrances, drugs and alternative fuels. Saccharomyces cerevisiae offers a versatile cell factory, as the precursors of terpenoid biosynthesis are naturally synthesized by the sterol biosynthetic pathway. Results S. cerevisiae wild type yeast cells, selected for their capacity to produce high sterol levels were targeted for improvement aiming to increase production. Recyclable integration cassettes were developed which enable the unlimited sequential integration of desirable genetic elements (promoters, genes, termination sequence at any desired locus in the yeast genome. The approach was applied on the yeast sterol biosynthetic pathway genes HMG2, ERG20 and IDI1 resulting in several-fold increase in plant monoterpene and sesquiterpene production. The improved strains were robust and could sustain high terpenoid production levels for an extended period. Simultaneous plasmid-driven co-expression of IDI1 and the HMG2 (K6R variant, in the improved strain background, maximized monoterpene production levels. Expression of two terpene synthase enzymes from the sage species Salvia fruticosa and S. pomifera (SfCinS1, SpP330 in the modified yeast cells identified a range of terpenoids which are also present in the plant essential oils. Co-expression of the putative interacting protein HSP90 with cineole synthase 1 (SfCinS1 also improved production levels, pointing to an additional means to improve production. Conclusions Using the developed molecular tools, new yeast strains were generated with increased capacity to produce plant terpenoids. The approach taken and the durability of the strains allow successive rounds of improvement to maximize yields.

Rat Strain Ontology: structured controlled vocabulary designed to facilitate access to strain data at RGD.

Science.gov (United States)

Nigam, Rajni; Munzenmaier, Diane H; Worthey, Elizabeth A; Dwinell, Melinda R; Shimoyama, Mary; Jacob, Howard J

2013-11-22

The Rat Genome Database (RGD) ( http://rgd.mcw.edu/) is the premier site for comprehensive data on the different strains of the laboratory rat (Rattus norvegicus). The strain data are collected from various publications, direct submissions from individual researchers, and rat providers worldwide. Rat strain, substrain designation and nomenclature follow the Guidelines for Nomenclature of Mouse and Rat Strains, instituted by the International Committee on Standardized Genetic Nomenclature for Mice. While symbols and names aid in identifying strains correctly, the flat nature of this information prohibits easy search and retrieval, as well as other data mining functions. In order to improve these functionalities, particularly in ontology-based tools, the Rat Strain Ontology (RS) was developed. The Rat Strain Ontology (RS) reflects the breeding history, parental background, and genetic manipulation of rat strains. This controlled vocabulary organizes strains by type: inbred, outbred, chromosome altered, congenic, mutant and so on. In addition, under the chromosome altered category, strains are organized by chromosome, and further by type of manipulations, such as mutant or congenic. This allows users to easily retrieve strains of interest with modifications in specific genomic regions. The ontology was developed using the Open Biological and Biomedical Ontology (OBO) file format, and is organized on the Directed Acyclic Graph (DAG) structure. Rat Strain Ontology IDs are included as part of the strain report (RS: ######). As rat researchers are often unaware of the number of substrains or altered strains within a breeding line, this vocabulary now provides an easy way to retrieve all substrains and accompanying information. Its usefulness is particularly evident in tools such as the PhenoMiner at RGD, where users can now easily retrieve phenotype measurement data for related strains, strains with similar backgrounds or those with similar introgressed regions. This

Resolution of axial shear strain elastography

International Nuclear Information System (INIS)

Thitaikumar, Arun; Righetti, Raffaella; Krouskop, Thomas A; Ophir, Jonathan

2006-01-01

The technique of mapping the local axial component of the shear strain due to quasi-static axial compression is defined as axial shear strain elastography. In this paper, the spatial resolution of axial shear strain elastography is investigated through simulations, using an elastically stiff cylindrical lesion embedded in a homogeneously softer background. Resolution was defined as the smallest size of the inclusion for which the strain value at the inclusion/background interface was greater than the average of the axial shear strain values at the interface and inside the inclusion. The resolution was measured from the axial shear strain profile oriented at 45 0 to the axis of beam propagation, due to the absence of axial shear strain along the normal directions. The effects of the ultrasound system parameters such as bandwidth, beamwidth and transducer element pitch along with signal processing parameters such as correlation window length (W) and axial shift (ΔW) on the estimated resolution were investigated. The results show that the resolution (at 45 0 orientation) is determined by the bandwidth and the beamwidth. However, the upper bound on the resolution is limited by the larger of the beamwidth and the window length, which is scaled inversely to the bandwidth. The results also show that the resolution is proportional to the pitch and not significantly affected by the axial window shift

Haldane model under nonuniform strain

Science.gov (United States)

Ho, Yen-Hung; Castro, Eduardo V.; Cazalilla, Miguel A.

2017-10-01

We study the Haldane model under strain using a tight-binding approach, and compare the obtained results with the continuum-limit approximation. As in graphene, nonuniform strain leads to a time-reversal preserving pseudomagnetic field that induces (pseudo-)Landau levels. Unlike a real magnetic field, strain lifts the degeneracy of the zeroth pseudo-Landau levels at different valleys. Moreover, for the zigzag edge under uniaxial strain, strain removes the degeneracy within the pseudo-Landau levels by inducing a tilt in their energy dispersion. The latter arises from next-to-leading order corrections to the continuum-limit Hamiltonian, which are absent for a real magnetic field. We show that, for the lowest pseudo-Landau levels in the Haldane model, the dominant contribution to the tilt is different from graphene. In addition, although strain does not strongly modify the dispersion of the edge states, their interplay with the pseudo-Landau levels is different for the armchair and zigzag ribbons. Finally, we study the effect of strain in the band structure of the Haldane model at the critical point of the topological transition, thus shedding light on the interplay between nontrivial topology and strain in quantum anomalous Hall systems.

A Modified Johnson-Cook Model for Sheet Metal Forming at Elevated Temperatures and Its Application for Cooled Stress-Strain Curve and Spring-Back Prediction

International Nuclear Information System (INIS)

Duc-Toan, Nguyen; Tien-Long, Banh; Young-Suk, Kim; Dong-Won, Jung

2011-01-01

In this study, a modified Johnson-Cook (J-C) model and an innovated method to determine (J-C) material parameters are proposed to predict more correctly stress-strain curve for tensile tests in elevated temperatures. A MATLAB tool is used to determine material parameters by fitting a curve to follow Ludwick's hardening law at various elevated temperatures. Those hardening law parameters are then utilized to determine modified (J-C) model material parameters. The modified (J-C) model shows the better prediction compared to the conventional one. As the first verification, an FEM tensile test simulation based on the isotropic hardening model for boron sheet steel at elevated temperatures was carried out via a user-material subroutine, using an explicit finite element code, and compared with the measurements. The temperature decrease of all elements due to the air cooling process was then calculated when considering the modified (J-C) model and coded to VUMAT subroutine for tensile test simulation of cooling process. The modified (J-C) model showed the good agreement between the simulation results and the corresponding experiments. The second investigation was applied for V-bending spring-back prediction of magnesium alloy sheets at elevated temperatures. Here, the combination of proposed J-C model with modified hardening law considering the unusual plastic behaviour for magnesium alloy sheet was adopted for FEM simulation of V-bending spring-back prediction and shown the good comparability with corresponding experiments.

Modeling of a Surface Acoustic Wave Strain Sensor

Science.gov (United States)

Wilson, W. C.; Atkinson, Gary M.

2010-01-01

NASA Langley Research Center is investigating Surface Acoustic Wave (SAW) sensor technology for harsh environments aimed at aerospace applications. To aid in development of sensors a model of a SAW strain sensor has been developed. The new model extends the modified matrix method to include the response of Orthogonal Frequency Coded (OFC) reflectors and the response of SAW devices to strain. These results show that the model accurately captures the strain response of a SAW sensor on a Langasite substrate. The results of the model of a SAW Strain Sensor on Langasite are presented

The shape of a strain-based failure assessment diagram

International Nuclear Information System (INIS)

Budden, P.J.; Ainsworth, R.A.

2012-01-01

There have been a number of recent developments of strain-based fracture assessment approaches, including proposals by Budden [Engng Frac Mech 2006;73:537–52] for a strain-based failure assessment diagram (FAD) related to the conventional stress-based FAD. However, recent comparisons with finite element (FE) data have shown that this proposed strain-based FAD can be non-conservative in some cases, particularly for deeper cracks and materials with little strain-hardening capacity. Therefore, this paper re-examines the shape of the strain-based FAD, guided by these FE analyses and some theoretical analysis. On this basis, modified proposals for the shape of the strain-based FAD are given, including simplified and more detailed options in line with the options available for stress-based FADs in existing fitness-for-service procedures. The proposals are then illustrated by a worked example and by comparison with FE data, which demonstrate that the new proposals are generally conservative. - Highlights: ► The strain-based failure assessment diagram approach to fracture is developed. ► The new approach modifies earlier proposals by Budden. ► A new generic Option 1 strain-based failure assessment diagram is proposed. ► Validation based on finite element J data for plates and cylinders is presented. ► The new approach is generally conservative compared with the finite element data.

High strain and strain-rate behaviour of PTFE/aluminium/tungsten mixtures

International Nuclear Information System (INIS)

Addiss, John; Walley, Stephen; Proud, William; Cai Jing; Nesterenko, Vitali

2007-01-01

Conventional drop-weight techniques were modified to accommodate low-amplitude force transducer signals from low-strength, cold isostatically pressed 'heavy' composites of polytetrafluoroethylene, aluminum and tungsten (W). The failure strength, strain and the post-critical behavior of failed samples were measured for samples of different porosity and tungsten grain size. Unusual phenomenon of significantly higher strength (55 MPa) of porous composites (density 5.9 g/cm 3 ) with small W particles ( 3 ) with larger W particles (44 μm) at the same volume content of components was observed. This is attributed to force chains created by a network of small W particles. Interrupted tests at different levels of strain revealed the mechanisms of fracture under dynamic compression

Segregation of genes from donor strain during the production of recombinant congenic strains.

Science.gov (United States)

van Zutphen, L F; Den Bieman, M; Lankhorst, A; Demant, P

1991-07-01

Recombinant congenic strains (RCS) constitute a set of inbred strains which are designed to dissect the genetic control of multigenic traits, such as tumour susceptibility or disease resistance. Each RCS contains a small fraction of the genome of a common donor strain, while the majority of genes stem from a common background strain. We tested at two stages of the inbreeding process in 20 RCS, derived from BALB/cHeA and STS/A, to see whether alleles from the STS/A donor strain are distributed over the RCS in a ratio as would theoretically be expected. Four marker genes (Pep-3; Pgm-1; Gpi-1 and Es-3) located at 4 different chromosomes were selected and the allelic distribution was tested after 3-4 and after 12 generations of inbreeding. The data obtained do not significantly deviate from the expected pattern, thus supporting the validity of the concept of RCS.

Influence of genetic background of engineered xylose-fermenting industrial Saccharomyces cerevisiae strains for ethanol production from lignocellulosic hydrolysates

Science.gov (United States)

An industrial ethanol-producing Saccharomyces cerevisiae strain with genes needed for xylose-fermentation integrated into its genome was used to obtain haploids and diploid isogenic strains. The isogenic strains were more effective in metabolizing xylose than their parental strain (p < 0.05) and abl...

Revitalizing genetically-modified mouse strains using frozen-thawed sperm after up to 192 h of refrigerated epididymis transportation.

Science.gov (United States)

Moreno-Del Val, Gonzalo; Muñoz-Robledano, Patricia

2017-10-01

In the scientific interchange of genetically-modified mouse strains the transportation of refrigerated epididymis has several advantages over the transportation of live animals, especially with regard to the 3R (replacement, reduction and refinement) principles. The major limiting factor is the duration of the transportation. Previous reports have shown that sperm collected from transported epididymis maintained their fertility for around 72 h, but there are no published data with longer transportation times, and this window of time may be too short, especially for international shipments and where locations are not well connected. In this study live pups were born using frozen-thawed sperm after up to 192 h (8 days) of transportation, using a special in vitro fertilization design which resulted in a fertilization rate of 10.5%.

Real-time reverse transcription polymerase chain reaction method for detection of Canine distemper virus modified live vaccine shedding for differentiation from infection with wild-type strains.

Science.gov (United States)

Wilkes, Rebecca P; Sanchez, Elena; Riley, Matthew C; Kennedy, Melissa A

2014-01-01

Canine distemper virus (CDV) remains a common cause of infectious disease in dogs, particularly in high-density housing situations such as shelters. Vaccination of all dogs against CDV is recommended at the time of admission to animal shelters and many use a modified live virus (MLV) vaccine. From a diagnostic standpoint for dogs with suspected CDV infection, this is problematic because highly sensitive diagnostic real-time reverse transcription polymerase chain reaction (RT-PCR) tests are able to detect MLV virus in clinical samples. Real-time PCR can be used to quantitate amount of virus shedding and can differentiate vaccine strains from wild-type strains when shedding is high. However, differentiation by quantitation is not possible in vaccinated animals during acute infection, when shedding is low and could be mistaken for low level vaccine virus shedding. While there are gel-based RT-PCR assays for differentiation of vaccine strains from field strains based on sequence differences, the sensitivity of these assays is unable to match that of the real-time RT-PCR assay currently used in the authors' laboratory. Therefore, a real-time RT-PCR assay was developed that detects CDV MLV vaccine strains and distinguishes them from wild-type strains based on nucleotide sequence differences, rather than the amount of viral RNA in the sample. The test is highly sensitive, with detection of as few as 5 virus genomic copies (corresponding to 10(-1) TCID(50)). Sequencing of the DNA real-time products also allows phylogenetic differentiation of the wild-type strains. This test will aid diagnosis during outbreaks of CDV in recently vaccinated animals.

Strains and Stressors: An Analysis of Touchscreen Learning in Genetically Diverse Mouse Strains

Science.gov (United States)

Graybeal, Carolyn; Bachu, Munisa; Mozhui, Khyobeni; Saksida, Lisa M.; Bussey, Timothy J.; Sagalyn, Erica; Williams, Robert W.; Holmes, Andrew

2014-01-01

Touchscreen-based systems are growing in popularity as a tractable, translational approach for studying learning and cognition in rodents. However, while mouse strains are well known to differ in learning across various settings, performance variation between strains in touchscreen learning has not been well described. The selection of appropriate genetic strains and backgrounds is critical to the design of touchscreen-based studies and provides a basis for elucidating genetic factors moderating behavior. Here we provide a quantitative foundation for visual discrimination and reversal learning using touchscreen assays across a total of 35 genotypes. We found significant differences in operant performance and learning, including faster reversal learning in DBA/2J compared to C57BL/6J mice. We then assessed DBA/2J and C57BL/6J for differential sensitivity to an environmental insult by testing for alterations in reversal learning following exposure to repeated swim stress. Stress facilitated reversal learning (selectively during the late stage of reversal) in C57BL/6J, but did not affect learning in DBA/2J. To dissect genetic factors underlying these differences, we phenotyped a family of 27 BXD strains generated by crossing C57BL/6J and DBA/2J. There was marked variation in discrimination, reversal and extinction learning across the BXD strains, suggesting this task may be useful for identifying underlying genetic differences. Moreover, different measures of touchscreen learning were only modestly correlated in the BXD strains, indicating that these processes are comparatively independent at both genetic and phenotypic levels. Finally, we examined the behavioral structure of learning via principal component analysis of the current data, plus an archival dataset, totaling 765 mice. This revealed 5 independent factors suggestive of “reversal learning,” “motivation-related late reversal learning,” “discrimination learning,” “speed to respond,” and �

Alteration of strain background and a high omega-6 fat diet induces earlier onset of pancreatic neoplasia in EL-Kras transgenic mice.

Science.gov (United States)

Cheon, Eric C; Strouch, Matthew J; Barron, Morgan R; Ding, Yongzeng; Melstrom, Laleh G; Krantz, Seth B; Mullapudi, Bhargava; Adrian, Kevin; Rao, Sambasiva; Adrian, Thomas E; Bentrem, David J; Grippo, Paul J

2011-06-15

Diets containing omega-6 (ω-6) fat have been associated with increased tumor development in carcinogen-induced pancreatic cancer models. However, the effects of ω-6 fatty acids and background strain on the development of genetically-induced pancreatic neoplasia is unknown. We assessed the effects of a diet rich in ω-6 fat on the development of pancreatic neoplasia in elastase (EL)-Kras(G12D) (EL-Kras) mice in two different backgrounds. EL-Kras FVB mice were crossed to C57BL/6 (B6) mice to produce EL-Kras FVB6 F1 (or EL-Kras F1) and EL-Kras B6 congenic mice. Age-matched EL-Kras mice from each strain were compared to one another on a standard chow. Two cohorts of EL-Kras FVB and EL-Kras F1 mice were fed a 23% corn oil diet and compared to age-matched mice fed a standard chow. Pancreata were scored for incidence, frequency, and size of neoplastic lesions, and stained for the presence of mast cells to evaluate changes in the inflammatory milieu secondary to a high fat diet. EL-Kras F1 mice had increased incidence, frequency, and size of pancreatic neoplasia compared to EL-Kras FVB mice. The frequency and size of neoplastic lesions and the weight and pancreatic mast cell densities in EL-Kras F1 mice were increased in mice fed a high ω-6 fatty acid diet compared to mice fed a standard chow. We herein introduce the EL-Kras B6 mouse model which presents with increased frequency of pancreatic neoplasia compared to EL-Kras F1 mice. The phenotype in EL-Kras F1 and FVB mice is promoted by a diet rich in ω-6 fatty acid. Copyright © 2010 UICC.

Modifiable risk factors of hypertension and socio demographic ...

African Journals Online (AJOL)

Background: Factors associated with the development of hypertension can be categorized into modifiable and non‑modifiable risk factors. The modifiable risk factors include obesity, physical inactivity, high salt diet, smoking alcohol consumption and others. Aim: This study was aimed to determine the prevalence of ...

Colony formation of C57BL/6J mice in visible burrow system: Identification of eusocial behaviors in a background strain for genetic animal models of autism

OpenAIRE

Arakawa, Hiroyuki; Blanchard, D. Caroline; Blanchard, Robert J.

2006-01-01

Deficits in social interaction are primary characteristics of autism, which has strong genetic components. Genetically-manipulated mouse models may provide a useful research tool to advance the investigation of genes associated with autism. To identify these genes using mouse models, behavioral assays for social relationships in the background strains must be developed. The present study examined colony formation in groups of one male and three female mice (Experiment 1) and, groups of three ...

Atlas of stress-strain curves

CERN Document Server

2002-01-01

The Atlas of Stress-Strain Curves, Second Edition is substantially bigger in page dimensions, number of pages, and total number of curves than the previous edition. It contains over 1,400 curves, almost three times as many as in the 1987 edition. The curves are normalized in appearance to aid making comparisons among materials. All diagrams include metric (SI) units, and many also include U.S. customary units. All curves are captioned in a consistent format with valuable information including (as available) standard designation, the primary source of the curve, mechanical properties (including hardening exponent and strength coefficient), condition of sample, strain rate, test temperature, and alloy composition. Curve types include monotonic and cyclic stress-strain, isochronous stress-strain, and tangent modulus. Curves are logically arranged and indexed for fast retrieval of information. The book also includes an introduction that provides background information on methods of stress-strain determination, on...

Benchmarking two commonly used Saccharomyces cerevisiae strains for heterologous vanillin-β-glucoside production

DEFF Research Database (Denmark)

Strucko, Tomas; Magdenoska, Olivera; Mortensen, Uffe Hasbro

2015-01-01

factories for production of specific compounds. To examine this possibility, we have reconstructed a de novo vanillin-β-glucoside pathway in an identical manner in S288c and CEN.PK strains. Characterization of the two resulting strains in two standard conditions revealed that the S288c background strain...... produced up to 10-fold higher amounts of vanillin-β-glucoside compared to CEN.PK. This study demonstrates that yeast strain background may play a major role in the outcome of newly developed cell factories for production of a given product....

Production of 5-ketofructose from fructose or sucrose using genetically modified Gluconobacter oxydans strains.

Science.gov (United States)

Siemen, Anna; Kosciow, Konrad; Schweiger, Paul; Deppenmeier, Uwe

2018-02-01

The growing consumer demand for low-calorie, sugar-free foodstuff motivated us to search for alternative non-nutritive sweeteners. A promising sweet-tasting compound is 5-keto-D-fructose (5-KF), which is formed by membrane-bound fructose dehydrogenases (Fdh) in some Gluconobacter strains. The plasmid-based expression of the fdh genes in Gluconobacter (G.) oxydans resulted in a much higher Fdh activity in comparison to the native host G. japonicus. Growth experiments with G. oxydans fdh in fructose-containing media indicated that 5-KF was rapidly formed with a conversion efficiency of 90%. 5-KF production from fructose was also observed using resting cells with a yield of about 100%. In addition, a new approach was tested for the production of the sweetener 5-KF by using sucrose as a substrate. To this end, a two-strain system composed of the fdh-expressing strain and a G. oxydans strain that produced the sucrose hydrolyzing SacC was developed. The strains were co-cultured in sucrose medium and converted 92.5% of the available fructose units into 5-KF. The glucose moiety of sucrose was converted to 2-ketogluconate and acetate. With regard to the development of a sustainable and resource-saving process for the production of 5-KF, sugar beet extract was used as substrate for the two-strain system. Fructose as product from sucrose cleavage was mainly oxidized to 5-KF which was detected in a concentration of over 200 mM at the end of the fermentation process. In summary, the two-strain system was able to convert fructose units of sugar beet extract to 5-KF with an efficiency of 82 ± 5%.

A genomically modified Escherichia coli strain carrying an orthogonal E. coli histidyl-tRNA synthetase•tRNAHis pair.

Science.gov (United States)

Englert, Markus; Vargas-Rodriguez, Oscar; Reynolds, Noah M; Wang, Yane-Shih; Söll, Dieter; Umehara, Takuya

2017-11-01

Development of new aminoacyl-tRNA synthetase (aaRS)•tRNA pairs is central for incorporation of novel non-canonical amino acids (ncAAs) into proteins via genetic code expansion (GCE). The Escherichia coli and Caulobacter crescentus histidyl-tRNA synthetases (HisRS) evolved divergent mechanisms of tRNA His recognition that prevent their cross-reactivity. Although the E. coli HisRS•tRNA His pair is a good candidate for GCE, its use in C. crescentus is limited by the lack of established genetic selection methods and by the low transformation efficiency of C. crescentus. E. coli was genetically engineered to use a C. crescentus HisRS•tRNA His pair. Super-folder green fluorescent protein (sfGFP) and chloramphenicol acetyltransferase (CAT) were used as reporters for read-through assays. A library of 313 ncAAs coupled with the sfGFP reporter system was employed to investigate the specificity of E. coli HisRS in vivo. A genomically modified E. coli strain (named MEOV1) was created. MEVO1 requires an active C. crescentus HisRS•tRNA His pair for growth, and displays a similar doubling time as the parental E. coli strain. sfGFP- and CAT-based assays showed that the E. coli HisRS•tRNA His pair is orthogonal in MEOV1 cells. A mutation in the anticodon loop of E. coli tRNA His CUA elevated its suppression efficiency by 2-fold. The C. crescentus HisRS•tRNA His pair functionally complements an E. coli ΔhisS strain. The E. coli HisRS•tRNA His is orthogonal in MEOV1 cells. E. coli tRNA His CUA is an efficient amber suppressor in MEOV1. We developed a platform that allows protein engineering of E. coli HisRS that should facilitate GCE in E. coli. This article is part of a Special Issue entitled "Biochemistry of Synthetic Biology - Recent Developments" Guest Editor: Dr. Ilka Heinemann and Dr. Patrick O'Donoghue. Copyright © 2017 Elsevier B.V. All rights reserved.

A molecular tool for detection and tracking of a potential indigenous Beauveria bassiana strain for managing emerald ash borer populations in Canada.

Science.gov (United States)

Johny, Shajahan; Kyei-Poku, George

2014-10-01

Emerald ash borer is an invasive species from Asia. Beauveria bassiana strain L49-1AA is being tested for the control of emerald ash borer in Canada, using an autocontamination trapping system. We have developed a simplified allele discrimination polymerase chain reaction (PCR) assay to screen B. bassiana strain, L49-1AA from other Beauveria species by targeting the inter-strain genetic differences in 5' end of EF1-α gene of the genus Beauveria. A single nucleotide polymorphism (SNP) site, T→C was identified only in L49-1AA and was used to develop a simplified allele discrimination polymerase chain reaction (PCR) assay based on a modified allelic inhibition of displacement activity (AIDA) approach for distinguishing B. bassiana L49-1AA from all background Beauveria isolates. The SNP site was employed to design inner primers but with a deliberate mismatch introduced at the 3' antepenultimate from the mutation site in order to maximize specificity and detection efficiency. Amplification was specific to L49-1AA without cross-reaction with DNA from other Beauveria strains. In addition, the designed primers were also tested against environmental samples in L49-1AA released plots and observed to be highly efficient in detecting and discriminating the target strain, L49-1AA from both pure and crude DNA samples. This new method can potentially allow for more discriminatory tracking and monitoring of released L49-1AA in our autocontamination and dissemination projects for managing EAB populations. Additionally, the modified-AIDA format has potential as a tool for simultaneously identifying and differentiating closely related Beauveria species, strains/isolates as well as general classification of other pathogens or organisms. Crown Copyright © 2014. Published by Elsevier Inc. All rights reserved.

Progress toward isolation of strains and genetically engineered strains of microalgae for production of biofuel and other value added chemicals: A review

International Nuclear Information System (INIS)

Ghosh, Ashmita; Khanra, Saumyakanti; Mondal, Madhumanti; Halder, Gopinath; Tiwari, O.N.; Saini, Supreet; Bhowmick, Tridib Kumar; Gayen, Kalyan

2016-01-01

Highlights: • Sample collection, isolation and identification to obtain a pure microalgal species. • Isolation of microalgal strains worldwide based on continent and habitat. • Genetic engineering tools for enhanced production of biodiesel and value added chemicals. • Cultivation systems for genetically modified strain. - Abstract: Microalgae and cyanobacteria are promising sources of biodiesel because of their high oil content (∼10 fold higher) and shorter cultivation time (∼4 fold lesser) than conventional oil producing territorial plants (e.g., soybean, corn and jatropha). These organisms also provide source of several valuable natural chemicals including pigments, food supplements like eicosapentanoic acid [EPA], decosahexaenoic acid [DHA] and vitamins. In addition, many cellular components of these organisms are associated with therapeutic properties like antioxidant, anti-inflammatory, immunostimulating, and antiviral. Isolation and identification of high-yielding strains with the faster growth rate is the key for successful implementation of algal biodiesel (or other products) at a commercial level. A number of research groups in Europe, America, and Australia are thus extensively involved in exploration of novel microalgal strain. Further, genetic engineering provides a tool to engineer the native strain resulting in transgenic strain with higher yields. Despite these efforts, no consensus has yet been reached so far in zeroing on the best microalgal strain for sustainable production of biofuel at reasonable cost. The search for novel microalgal strain and transgenesis of microalgae, are continuing side by side with the hope of commercial scale production of microalgae biofuel in near future. However, no consolidated review report exists which guides to isolate and identify a uncontaminated microalgal strain along with their transgenesis. The present review is focused on: (i) key factors for sample collection, isolation, and identification to

Visualization of bonding at an inclusion boundary using axial-shear strain elastography: a feasibility study

International Nuclear Information System (INIS)

Thitaikumar, Arun; Krouskop, Thomas A; Garra, Brian S; Ophir, Jonathan

2007-01-01

Ultrasound elastography produces strain images of compliant tissues under quasi-static compression. In axial-shear strain elastography, the local axial-shear strain resulting from application of quasi-static axial compression to an inhomogeneous material is imaged. The overall hypothesis of this work is that the pattern of axial-shear strain distribution around the inclusion/background interface is completely determined by the bonding at the interface after normalization for inclusion size and applied strain levels, and that it is feasible to extract certain features from the axial-shear strain elastograms to quantify this pattern. The mechanical model used in this study consisted of a single stiff circular inclusion embedded in a homogeneous softer background. First, we performed a parametric study using finite-element analysis (FEA) (no ultrasound involved) to identify possible features that quantify the pattern of axial-shear strain distribution around an inclusion/background interface. Next, the ability to extract these features from axial-shear strain elastograms, estimated from simulated pre- and post-compression noisy RF data, was investigated. Further, the feasibility of extracting these features from in vivo breast data of benign and malignant tumors was also investigated. It is shown using the FEA study that the pattern of axial-shear strain distribution is determined by the degree of bonding at the inclusion/background interface. The results suggest the feasibility of using normalized features that capture the region of positive and negative axial-shear strain area to quantify the pattern of the axial-shear strain distribution. The simulation results showed that it was feasible to extract the features, as identified in the FEA study, from axial-shear strain elastograms. However, an effort must be made to obtain axial-shear strain elastograms with the highest signal-to-noise ratio (SNR asse ) possible, without compromising the resolution. The in vivo

The acute stress response of red porgy, Pagrus pagrus, kept on a red or white background

NARCIS (Netherlands)

Salm, A.L. van der; Pavlidis, M; Flik, G.; Wendelaar Bonga, S.E.

2005-01-01

The skin colour of red porgy, Pagrus pagrus, can be modified by exposure to different background colours. Red and white background colours brighten the dark skin colour that develops under common culture conditions in red porgy. To assess whether skin colour is also modified by aquaculture related

A modified Johnson–Cook model of dynamic tensile behaviors for 7075-T6 aluminum alloy

Energy Technology Data Exchange (ETDEWEB)

Zhang, Ding-Ni, E-mail: siping4840@126.com [The College of Information, Mechanical and Electrical Engineering, Shanghai Normal University, Shanghai 200234 (China); Shangguan, Qian-Qian [The College of Information, Mechanical and Electrical Engineering, Shanghai Normal University, Shanghai 200234 (China); Xie, Can-Jun [Commercial Aircraft Corporation of China, Ltd., Shanghai 200120 (China); Liu, Fu [Shanghai Aircraft Design and Research Institute of COMAC, Shanghai 201210 (China)

2015-01-15

Highlights: • The dynamic mechanical behaviors at various strain rates were measured. • The strain rate hardening effect of 7075-T6 aluminum alloy is significant. • A new Johnson–Cook constitutive model of 7075-T6 aluminum alloy was obtained. • Numerical simulations of tensile tests at different rates were conducted. • Accuracy of the modified Johnson–Cook constitutive equation was proved. - Abstract: The dynamic mechanical behaviors of 7075-T6 aluminum alloy at various strain rates were measured by dynamic tensile tests using the electronic universal testing machine, high velocity testing system and split Hopkinson tensile bar (SHTB). Stress–strain curves at different rates were obtained. The results show that the strain rate hardening effect of 7075-T6 aluminum alloy is significant. By modifying the strain rate hardening term in the Johnson–Cook constitutive model, a new Johnson–Cook (JC) constitutive model of 7075-T6 aluminum alloy was obtained. The improved Johnson–Cook model matched the experiment results very well. With the Johnson–Cook constitutive model, numerical simulations of tensile tests at different rates for 7075-T6 aluminum alloy were conducted. According to tensile loading and stress–strain relation of 7075-T6 aluminum alloy, calculation results were compared with experimental results. Accuracy of the modified Johnson–Cook constitutive equation was further proved.

A modified Johnson–Cook model of dynamic tensile behaviors for 7075-T6 aluminum alloy

International Nuclear Information System (INIS)

Zhang, Ding-Ni; Shangguan, Qian-Qian; Xie, Can-Jun; Liu, Fu

2015-01-01

Highlights: • The dynamic mechanical behaviors at various strain rates were measured. • The strain rate hardening effect of 7075-T6 aluminum alloy is significant. • A new Johnson–Cook constitutive model of 7075-T6 aluminum alloy was obtained. • Numerical simulations of tensile tests at different rates were conducted. • Accuracy of the modified Johnson–Cook constitutive equation was proved. - Abstract: The dynamic mechanical behaviors of 7075-T6 aluminum alloy at various strain rates were measured by dynamic tensile tests using the electronic universal testing machine, high velocity testing system and split Hopkinson tensile bar (SHTB). Stress–strain curves at different rates were obtained. The results show that the strain rate hardening effect of 7075-T6 aluminum alloy is significant. By modifying the strain rate hardening term in the Johnson–Cook constitutive model, a new Johnson–Cook (JC) constitutive model of 7075-T6 aluminum alloy was obtained. The improved Johnson–Cook model matched the experiment results very well. With the Johnson–Cook constitutive model, numerical simulations of tensile tests at different rates for 7075-T6 aluminum alloy were conducted. According to tensile loading and stress–strain relation of 7075-T6 aluminum alloy, calculation results were compared with experimental results. Accuracy of the modified Johnson–Cook constitutive equation was further proved

Does race/ethnicity moderate the association between job strain and leisure time physical activity?

Science.gov (United States)

Bennett, Gary G; Wolin, Kathleen Y; Avrunin, Jill S; Stoddard, Anne M; Sorensen, Glorian; Barbeau, Elizabeth; Emmons, Karen M

2006-08-01

Racial/ethnic minorities report myriad barriers to regular leisure time physical activity (LTPA), including the stress and fatigue resulting from their occupational activities. We sought to investigate whether an association exists between job strain and LTPA, and whether it is modified by race or ethnicity. Data were collected from 1,740 adults employed in 26 small manufacturing businesses in eastern Massachusetts. LTPA and job strain data were self-reported. Adjusted mean hours of LTPA per week are reported. In age and gender adjusted analyses, reports of job strain were associated with LTPA. There was a significant interaction between job strain and race or ethnicity (p = .04). Whites experiencing job strain reported 1 less hr of LTPA per week compared to Whites not reporting job strain. Collectively, racial/ethnic minorities reporting job strain exhibited comparatively higher levels of LTPA compared to their counterparts with no job strain, although patterns for individual groups did not significantly differ. Job strain was associated with LTPA in a lower income, multiethnic population of healthy adult men and women. The association between job strain and LTPA was modified by race or ethnicity, highlighting the importance of investigating the differential effects of psychosocial occupational factors on LTPA levels by race or ethnicity.

The background scale Ward identity in quantum gravity

Energy Technology Data Exchange (ETDEWEB)

Percacci, Roberto [International School for Advanced Studies, Trieste (Italy); INFN, Sezione di Trieste, Trieste (Italy); Vacca, Gian Paolo [INFN, Sezione di Bologna, Bologna (Italy)

2017-01-15

We show that with suitable choices of parametrization, gauge fixing and cutoff, the anomalous variation of the effective action under global rescalings of the background metric is identical to the derivative with respect to the cutoff, i.e. to the beta functional, as defined by the exact RG equation. The Ward identity and the RG equation can be combined, resulting in a modified flow equation that is manifestly invariant under global background rescalings. (orig.)

Validation of the Chinese version of the Modified Caregivers Strain Index among Hong Kong caregivers: an initiative of medical social workers.

Science.gov (United States)

Chan, Wallace Chi Ho; Chan, Christopher L F; Suen, Margaret

2013-11-01

Family caregivers may often experience caregiving stress and burden. To systematically assess this issue, medical social workers may need to use a brief and valid measurement in their practice. In the Hong Kong Chinese context, one additional challenge is to examine whether a measurement developed in the West is valid for Hong Kong Chinese caregivers. Thus, medical social workers in Hong Kong initiated this research study to validate the Chinese version of the Modified Caregiver Strain Index (C-M-CSI). A total of 223 Chinese caregivers of patients with various chronic illnesses were recruited for this validation study. C-M-CSI demonstrated good reliability (Cronbach's alpha coefficient = .91), concurrent validity with the Chinese version of the Caregiver Burden Inventory, and discriminant validity with the Chinese version of the Meaning in Life Questionnaire. Factor analysis yielded a single factor as the original M-CSI, which explained 49 percent of variance. Construct validity was shown by differentiating spousal and nonspousal caregivers, as well as caregivers of patients with and without behavioral problems. C-M-CSI is recommended as a brief and valid measurement that can be used by medical social workers in assessing the caregiving strain of Chinese caregivers of patients in Hong Kong.

Fatigue properties of JIS H3300 C1220 copper for strain life prediction

Science.gov (United States)

Harun, Muhammad Faiz; Mohammad, Roslina

2018-05-01

The existing methods for estimating strain life parameters are dependent on the material's monotonic tensile properties. However, a few of these methods yield quite complicated expressions for calculating fatigue parameters, and are specific to certain groups of materials only. The Universal Slopes method, Modified Universal Slopes method, Uniform Material Law, the Hardness method, and Medians method are a few existing methods for predicting strain-life fatigue based on monotonic tensile material properties and hardness of material. In the present study, nine methods for estimating fatigue life and properties are applied on JIS H3300 C1220 copper to determine the best methods for strain life estimation of this ductile material. Experimental strain-life curves are compared to estimations obtained using each method. Muralidharan-Manson's Modified Universal Slopes method and Bäumel-Seeger's method for unalloyed and low-alloy steels are found to yield batter accuracy in estimating fatigue life with a deviation of less than 25%. However, the prediction of both methods only yield much better accuracy for a cycle of less than 1000 or for strain amplitudes of more than 1% and less than 6%. Manson's Original Universal Slopes method and Ong's Modified Four-Point Correlation method are found to predict the strain-life fatigue of copper with better accuracy for a high number of cycles of strain amplitudes of less than 1%. The differences between mechanical behavior during monotonic and cyclic loading and the complexity in deciding the coefficient in an equation are probably the reason for the lack of a reliable method for estimating fatigue behavior using the monotonic properties of a group of materials. It is therefore suggested that a differential approach and new expressions be developed to estimate the strain-life fatigue parameters for ductile materials such as copper.

Triacetic acid lactone production in industrial Saccharomyces yeast strains

Science.gov (United States)

Triacetic acid lactone (TAL) is a potential platform chemical that can be produced in yeast. To evaluate the potential for industrial yeast strains to produce TAL, the g2ps1 gene encoding 2-pyrone synthase was transformed into thirteen industrial yeast strains of varied genetic background. TAL produ...

Heterologous protein secretion in Lactobacilli with modified pSIP vectors.

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Ingrid Lea Karlskås

Full Text Available We describe new variants of the modular pSIP-vectors for inducible gene expression and protein secretion in lactobacilli. The basic functionality of the pSIP system was tested in Lactobacillus strains representing 14 species using pSIP411, which harbors the broad-host-range Lactococcus lactis SH71rep replicon and a β-glucuronidase encoding reporter gene. In 10 species, the inducible gene expression system was functional. Based on these results, three pSIP vectors with different signal peptides were modified by replacing their narrow-host-range L. plantarum 256rep replicon with SH71rep and transformed into strains of five different species of Lactobacillus. All recombinant strains secreted the target protein NucA, albeit with varying production levels and secretion efficiencies. The Lp_3050 derived signal peptide generally resulted in the highest levels of secreted NucA. These modified pSIP vectors are useful tools for engineering a wide variety of Lactobacillus species.

Simulation of PEP-II Accelerator Backgrounds Using TURTLE

CERN Document Server

Barlow, Roger J; Kozanecki, Witold; Majewski, Stephanie; Roudeau, Patrick; Stocchi, Achille

2005-01-01

We present studies of accelerator-induced backgrounds in the BaBar detector at the SLAC B-Factory, carried out using a modified version ofthe DECAY TURTLE simulation package. Lost-particle backgrounds in PEP-II are dominated by a combination of beam-gas bremstrahlung, beam-gas Coulomb scattering, radiative-Bhabha events and beam-beam blow-up. The radiation damage and detector occupancy caused by the associated electromagnetic shower debris can limit the usable luminosity. In order to understand and mitigate such backgrounds, we have performed a full programme of beam-gas and luminosity-background simulations, that include the effects of the detector solenoidal field, detailed modelling of limiting apertures in both collider rings, and optimization of the betatron collimation scheme in the presence of large transverse tails.

Solving ethanol production problems with genetically modified yeast strains

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A. Abreu-Cavalheiro

2013-09-01

Full Text Available The current world demand for bioethanol is increasing as a consequence of low fossil fuel availability and a growing number of ethanol/gasoline flex-fuel cars. In addition, countries in several parts of the world have agreed to reduce carbon dioxide emissions, and the use of ethanol as a fuel (which produces fewer pollutants than petroleum products has been considered to be a good alternative to petroleum products. The ethanol that is produced in Brazil from the first-generation process is optimized and can be accomplished at low cost. However, because of the large volume of ethanol that is produced and traded each year, any small improvement in the process could represent a savings of billions dollars. Several Brazilian research programs are investing in sugarcane improvement, but little attention has been given to the improvement of yeast strains that participate in the first-generation process at present. The Brazilian ethanol production process uses sugarcane as a carbon source for the yeast Saccharomyces cerevisiae. Yeast is then grown at a high cellular density and high temperatures in large-capacity open tanks with cells recycle. All of these culture conditions compel the yeast to cope with several types of stress. Among the main stressors are high temperatures and high ethanol concentrations inside the fermentation tanks during alcohol production. Moreover, the competition between the desired yeast strains, which are inoculated at the beginning of the process, with contaminants such as wild type yeasts and bacteria, requires acid treatment to successfully recycle the cells. This review is focused on describing the problems and stressors within the Brazilian ethanol production system. It also highlights some genetic modifications that can help to circumvent these difficulties in yeast.

Solving ethanol production problems with genetically modified yeast strains.

Science.gov (United States)

Abreu-Cavalheiro, A; Monteiro, G

2013-01-01

The current world demand for bioethanol is increasing as a consequence of low fossil fuel availability and a growing number of ethanol/gasoline flex-fuel cars. In addition, countries in several parts of the world have agreed to reduce carbon dioxide emissions, and the use of ethanol as a fuel (which produces fewer pollutants than petroleum products) has been considered to be a good alternative to petroleum products. The ethanol that is produced in Brazil from the first-generation process is optimized and can be accomplished at low cost. However, because of the large volume of ethanol that is produced and traded each year, any small improvement in the process could represent a savings of billions dollars. Several Brazilian research programs are investing in sugarcane improvement, but little attention has been given to the improvement of yeast strains that participate in the first-generation process at present. The Brazilian ethanol production process uses sugarcane as a carbon source for the yeast Saccharomyces cerevisiae. Yeast is then grown at a high cellular density and high temperatures in large-capacity open tanks with cells recycle. All of these culture conditions compel the yeast to cope with several types of stress. Among the main stressors are high temperatures and high ethanol concentrations inside the fermentation tanks during alcohol production. Moreover, the competition between the desired yeast strains, which are inoculated at the beginning of the process, with contaminants such as wild type yeasts and bacteria, requires acid treatment to successfully recycle the cells. This review is focused on describing the problems and stressors within the Brazilian ethanol production system. It also highlights some genetic modifications that can help to circumvent these difficulties in yeast.

Benchmarking two commonly used Saccharomyces cerevisiae strains for heterologous vanillin-β-glucoside production

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Tomas Strucko

2015-12-01

Full Text Available The yeast Saccharomyces cerevisiae is a widely used eukaryotic model organism and a key cell factory for production of biofuels and wide range of chemicals. From the broad palette of available yeast strains, the most popular are those derived from laboratory strain S288c and the industrially relevant CEN.PK strain series. Importantly, in recent years these two strains have been subjected to comparative “-omics” analyzes pointing out significant genotypic and phenotypic differences. It is therefore possible that the two strains differ significantly with respect to their potential as cell factories for production of specific compounds. To examine this possibility, we have reconstructed a de novo vanillin-β-glucoside pathway in an identical manner in S288c and CEN.PK strains. Characterization of the two resulting strains in two standard conditions revealed that the S288c background strain produced up to 10-fold higher amounts of vanillin-β-glucoside compared to CEN.PK. This study demonstrates that yeast strain background may play a major role in the outcome of newly developed cell factories for production of a given product. Keywords: Yeast, Cell factory, Strain choice, Heterologous production, Vanillin-glucoside, Shikimate pathway

Genome Analysis of Legionella pneumophila Strains Using a Mixed-Genome Microarray

NARCIS (Netherlands)

Euser, S.M.; Nagelkerke, N.J.; Schuren, F.; Jansen, R.; Boer, J.W. den

2012-01-01

Background: Legionella, the causative agent for Legionnaires' disease, is ubiquitous in both natural and man-made aquatic environments. The distribution of Legionella genotypes within clinical strains is significantly different from that found in environmental strains. Developing novel genotypic

Changes in the vibrational properties of graphene and other related nanostructures under strain

International Nuclear Information System (INIS)

Codorniu Pujals, D.

2015-01-01

It is well known that the presence of strain in solids modifies their vibrational properties due to the variation of the atomic position and the changes of the interatomic distances. Monolayer graphene is especially sensible to the effects of strain, for example, to that produced by the curvature of some region of the graphene plane. These changes in the vibrational properties of graphene modifies in different way its Raman spectrum. In the case of other graphene-related materials as fullerenes, nano-onions and nano tubes, the curvature is always present, consequently, there is a modification of the vibrational properties in relation with those in graphene, due to the strain provoked by curvature. In this paper, the overall picture of the effect of strain on the vibrational properties of graphene and other carbon nanostructures is presented from a theoretical point of view and the main considerations are correlated with experimental results from Raman spectroscopy (Author)

Strain induced anomalous red shift in mesoscopic iron oxide ...

Indian Academy of Sciences (India)

Wintec

pared to spherical ones. The red shift is attributed to strain induced changes in internal pressure inside the ..... Shape control can also induce anisotropy and thus modify the coercivity of these ... ppines: Addison-Wesley Publishing Company).

Establishment and comparison of four constitutive relationships of PC/ABS from low to high uniaxial strain rates

Science.gov (United States)

Wang, Haitao; Zhang, Yun; Huang, Zhigao; Tang, Zhongbin; Wang, Yanpei; Zhou, Huamin

2017-10-01

The objective of this paper is to accurately predict the rate/temperature-dependent deformation of a polycarbonate (PC) and acrylonitrile-butadiene-styrene (ABS) blend at low, moderate, and high strain rates for various temperatures. Four constitutive models have been employed to predict stress-strain responses of PC/ABS under these conditions, including the DSGZ model, the original Mulliken-Boyce (M-B) model, the modified M-B model, and an adiabatic model named the Wang model. To more accurately capture the large deformation of PC/ABS under the high strain rate loading, the original M-B model is modified by allowing for the evolution of the internal shear strength. All of the four constitutive models above have been implemented in the finite element software ABAQUS/Explicit. A comparison of prediction accuracies of the four constitutive models over a wide range of strain rates and temperatures has been presented. The modified M-B model is observed to be more accurate in predicting the deformation of PC/ABS at high strain rates for various temperatures than the original M-B model, and the Wang model is demonstrated to be the most accurate in simulating the deformation of PC/ABS at low, moderate, and high strain rates for various temperatures.

NEW PRODUCER STRAINS OF BIOBUTANOL. І. ISOLATION AND IDENTIFICATION

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O. A. Tigunova

2013-02-01

Full Text Available Getting new, more productive strains of microorganisms that produce butanol is a topical problem. Studing of morphological and physiological characteristics of the isolated strains, improvement of their cultivation conditions, optimization of biobutanol synthesis gives the possibility to organize a cost-effective butanol production technology. The aim of this work was searching new butanol and butyric acid producer strains, their identification and studying the main steps of the selective strains biosynthesis. The objects of this study were microorganisms that had allocated from soils and sludges samples of Kiev’s lakes. Obtained cultures have been screened. Three strains were obtained as promising and identified as C. acetobutylicum, C. tyrobutylicum, C. butylicum. Selective medium have been developed and modified for the microorganisms. Producer’s features were investigated in order to maximize the accumulation of target metabolites.

Strain-engineered growth of two-dimensional materials.

Science.gov (United States)

Ahn, Geun Ho; Amani, Matin; Rasool, Haider; Lien, Der-Hsien; Mastandrea, James P; Ager Iii, Joel W; Dubey, Madan; Chrzan, Daryl C; Minor, Andrew M; Javey, Ali

2017-09-20

The application of strain to semiconductors allows for controlled modification of their band structure. This principle is employed for the manufacturing of devices ranging from high-performance transistors to solid-state lasers. Traditionally, strain is typically achieved via growth on lattice-mismatched substrates. For two-dimensional (2D) semiconductors, this is not feasible as they typically do not interact epitaxially with the substrate. Here, we demonstrate controlled strain engineering of 2D semiconductors during synthesis by utilizing the thermal coefficient of expansion mismatch between the substrate and semiconductor. Using WSe 2 as a model system, we demonstrate stable built-in strains ranging from 1% tensile to 0.2% compressive on substrates with different thermal coefficient of expansion. Consequently, we observe a dramatic modulation of the band structure, manifested by a strain-driven indirect-to-direct bandgap transition and brightening of the dark exciton in bilayer and monolayer WSe 2 , respectively. The growth method developed here should enable flexibility in design of more sophisticated devices based on 2D materials.Strain engineering is an essential tool for modifying local electronic properties in silicon-based electronics. Here, Ahn et al. demonstrate control of biaxial strain in two-dimensional materials based on the growth substrate, enabling more complex low-dimensional electronics.

Field release of genetically modified Pseudomonas putida WCS358r : molecular analysis of effects on microbial communities in the rhizosphere of wheat

NARCIS (Netherlands)

Viebahn, Mareike

2005-01-01

Genetically modified microorganisms (GMMs) with enhanced biocontrol activity are attractive to apply in agriculture. To investigate potential ecological risks of field introduction of GMMs, effects of P. putida strain WCS358r and two genetically modified derivatives of this strain on the indigenous

Simulation of cyclic stress-strain relation under non proportional loading

International Nuclear Information System (INIS)

Chen, X.; Zhu, Q.X.; Abel, A.

1995-01-01

A series of cyclic constitutive experiments have been conducted on 42 Cr Mo steel on MTS809 machine under tension-torsional loading. Thin-walled tube specimen were used. Two kinds of cruciform strain path have been investigated. The paper suggests a simple method for the calculation of stable cyclic stress and strain values based on a modified endochronic constitutive theory by redefined intrinsic time scale. (author). 6 refs., 3 figs

Model-based methodology to develop the isochronous stress-strain curves for modified 9Cr steels

International Nuclear Information System (INIS)

Kim, Woo Gon; Yin, Song Nan; Kim, Sung Ho; Lee, Chan Bock; Jung, Ik Hee

2008-01-01

Since high temperature materials are designed with a target life based on a specified amount of allowable strain and stress, their Isochronous Stress-Strain Curves (ISSC) are needed to avoid an excessive deformation during an intended service life. In this paper, a model-based methodology to develop the isochronous curves for a G91 steel is described. Creep strain-time curves were reviewed for typical high-temperature materials, and Garofalo's model which conforms well to the primary and secondary creep stages was proper for the G91 steel. Procedures to obtain an instantaneous elastic-plastic strain, ε i were given in detail. Also, to accurately determine the P 1 , P 2 and P 3 parameters in the Garofalo's model, a Nonlinear Least Square Fitting (NLSF) method was adopted and useful. The long-term creep curves for the G91 steel can be modeled by the Garofalo's model, and the long-term ISSCs can be developed using the modeled creep curves

Listeria monocytogenes repellence by enzymatically modified PES surfaces

NARCIS (Netherlands)

Veen, van der S.; Nady, N.; Franssen, M.C.R.; Zuilhof, H.; Boom, R.M.; Abee, T.; Schroën, C.G.P.H.

2015-01-01

: The effect of enzyme-catalyzed modification of poly(ethersulfone) (PES) on the adhesion and biofilm formation of two Listeria monocytogenes strains is evaluated under static and dynamic flow conditions. PES has been modified with gallic acid, ferulic acid and 4-hydroxybenzoic acid. The surfaces

Highly efficient gene targeting in Aspergillus oryzae industrial strains under ligD mutation introduced by genome editing: Strain-specific differences in the effects of deleting EcdR, the negative regulator of sclerotia formation.

Science.gov (United States)

Nakamura, Hidetoshi; Katayama, Takuya; Okabe, Tomoya; Iwashita, Kazuhiro; Fujii, Wataru; Kitamoto, Katsuhiko; Maruyama, Jun-Ichi

2017-07-11

Numerous strains of Aspergillus oryzae are industrially used for Japanese traditional fermentation and for the production of enzymes and heterologous proteins. In A. oryzae, deletion of the ku70 or ligD genes involved in non-homologous end joining (NHEJ) has allowed high gene targeting efficiency. However, this strategy has been mainly applied under the genetic background of the A. oryzae wild strain RIB40, and it would be laborious to delete the NHEJ genes in many A. oryzae industrial strains, probably due to their low gene targeting efficiency. In the present study, we generated ligD mutants from the A. oryzae industrial strains by employing the CRISPR/Cas9 system, which we previously developed as a genome editing method. Uridine/uracil auxotrophic strains were generated by deletion of the pyrG gene, which was subsequently used as a selective marker. We examined the gene targeting efficiency with the ecdR gene, of which deletion was reported to induce sclerotia formation under the genetic background of the strain RIB40. As expected, the deletion efficiencies were high, around 60~80%, in the ligD mutants of industrial strains. Intriguingly, the effects of the ecdR deletion on sclerotia formation varied depending on the strains, and we found sclerotia-like structures under the background of the industrial strains, which have never been reported to form sclerotia. The present study demonstrates that introducing ligD mutation by genome editing is an effective method allowing high gene targeting efficiency in A. oryzae industrial strains.

Free vibration and biaxial buckling analysis of magneto-electro-elastic microplate resting on visco-Pasternak substrate via modified strain gradient theory

Science.gov (United States)

Jamalpoor, A.; Ahmadi-Savadkoohi, A.; Hosseini-Hashemi, Sh

2016-10-01

This paper deals with the theoretical analysis of free vibration and biaxial buckling of magneto-electro-elastic (MEE) microplate resting on Kelvin-Voigt visco-Pasternak foundation and subjected to initial external electric and magnetic potentials, using modified strain gradient theory (MSGT). Kirchhoff plate model and Hamilton’s principle are employed to extract the governing equations of motion. Governing equations were analytically solved to obtain clear closed-form expression for complex natural frequencies and buckling loads using Navier’s approach. Numerical results are presented to reveal variations of natural frequency and buckling load ratio of MEE microplate against different amounts of the length scale parameter, initial external electric and magnetic potentials, aspect ratio, damping and transverse and shear stiffness parameters of the visco-Pasternak foundation, length to thickness ratio, microplate thickness and higher modes. Numerical results of this study illustrate that by increasing thickness-to-material length scale parameter ratio, both natural frequency and buckling load ratio predicted by MSGT and modified couple stress theory are reduced because the non-dimensional length scale parameter tends to decrease the stiffness of structures and make them more flexible. In addition, results show that initial external electric and initial external magnetic potentials have no considerable influence on the buckling load ratio and frequency of MEE microplate as the microplate thickness increases.

Efficacy of the Non-Pathogenic Agrobacterium Strains K84 and K1026 against Crown Gall in Tunisia

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A. Rhouma

2004-08-01

Full Text Available The non-pathogenic Agrobacterium radiobacter strain K84 and its genetically modified (GEM strain K1026 were tested for their effectiveness against local Tunisian strains and two reference strains (C58 and B6 of the crown gall bacterium Agrobacterium tumefaciens. Tests in planta were carried out on herbaceous plants (tomato and tagetes and on some sensitive rootstocks (bitter almond, peach almond hybrid GF677 and quince BA29. In vitro tests showed that both K84 and K1026 were effective and that the difference between these strains was not statistically significant. On tomato and tagetes, strain K84 was effective against all crown gall isolates with the exception of the A. tumefaciens reference strain B6. GEM strain K1026 was very effective against all isolates from Tunisia and against the reference strains. Both antagonistic strains significantly reduced the percentage of galled plants as well as the number of galls per plant. Under field conditions, both antagonists controlled crown gall effectively. Best results were obtained on the bitter almond-tree rootstock. Antagonist effectiveness was less evident on quince BA29 and peach almond GF677 rootstocks. The genetically modified strain K1026 is of interest in controlling crown gall disease in Tunisia.

Dark field electron holography for strain measurement

Energy Technology Data Exchange (ETDEWEB)

Beche, A., E-mail: armand.beche@fei.com [CEA-Grenoble, INAC/SP2M/LEMMA, F-38054 Grenoble (France); Rouviere, J.L. [CEA-Grenoble, INAC/SP2M/LEMMA, F-38054 Grenoble (France); Barnes, J.P.; Cooper, D. [CEA-LETI, Minatec Campus, F-38054 Grenoble (France)

2011-02-15

Dark field electron holography is a new TEM-based technique for measuring strain with nanometer scale resolution. Here we present the procedure to align a transmission electron microscope and obtain dark field holograms as well as the theoretical background necessary to reconstruct strain maps from holograms. A series of experimental parameters such as biprism voltage, sample thickness, exposure time, tilt angle and choice of diffracted beam are then investigated on a silicon-germanium layer epitaxially embedded in a silicon matrix in order to obtain optimal dark field holograms over a large field of view with good spatial resolution and strain sensitivity. -- Research Highlights: {yields} Step by step explanation of the dark field electron holography technique. {yields} Presentation of the theoretical equations to obtain quantitative strain map. {yields} Description of experimental parameters influencing dark field holography results. {yields} Quantitative strain measurement on a SiGe layer embedded in a silicon matrix.

Family resources study: part 1: family resources, family function and caregiver strain in childhood cancer

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Panganiban-Corales Avegeille T

2011-10-01

Full Text Available Abstract Background Severe illness can disrupt family life, cause family dysfunction, strain resources, and cause caregiver burden. The family's ability to cope with crises depends on their resources. This study sought to assess families of children with cancer in terms of family function-dysfunction, family caregiver strain and the adequacy of family resources using a new family resources assessment instrument. Methods This is a cross-sectional study involving 90 Filipino family caregivers of children undergoing cancer treatment. This used a self-administered questionnaire composed of a new 12-item family resources questionnaire (SCREEM-RES based on the SCREEM method of analysis, Family APGAR to assess family function-dysfunction; and Modified Caregiver Strain Index to assess strain in caring for the patient. Results More than half of families were either moderately or severely dysfunctional. Close to half of caregivers were either predisposed to strain or experienced severe strain, majority disclosed that their families have inadequate economic resources; many also report inaccessibility to medical help in the community and insufficient educational resources to understand and care for their patients. Resources most often reported as adequate were: family's faith and religion; help from within the family and from health providers. SCREEM-RES showed to be reliable with Cronbach's alpha of 0.80. There is good inter-item correlation between items in each domain: 0.24-0.70. Internal consistency reliability for each domain was also good: 0.40-0.92. Using 2-point scoring system, Cronbach's alpha were slightly lower: full scale (0.70 and for each domain 0.26-.82. Results showed evidence of association between family resources and family function based on the family APGAR but none between family resources and caregiver strain and between family function and caregiver strain. Conclusion Many Filipino families of children with cancer have inadequate

Classical Swine Fever Outbreak after Modified Live LOM Strain Vaccination in Naive Pigs, South Korea

Science.gov (United States)

Je, Sang H.; Kwon, Taeyong; Yoo, Sung J.; Lee, Dong-Uk; Lee, SeungYoon; Richt, Juergen A.

2018-01-01

We report classical swine fever outbreaks occurring in naive pig herds on Jeju Island, South Korea, after the introduction of the LOM vaccine strain. Two isolates from sick pigs had >99% identity with the vaccine stain. LOM strain does not appear safe; its use in the vaccine should be reconsidered. PMID:29553332

Breeding of a xylose-fermenting hybrid strain by mating genetically engineered haploid strains derived from industrial Saccharomyces cerevisiae.

Science.gov (United States)

Inoue, Hiroyuki; Hashimoto, Seitaro; Matsushika, Akinori; Watanabe, Seiya; Sawayama, Shigeki

2014-12-01

The industrial Saccharomyces cerevisiae IR-2 is a promising host strain to genetically engineer xylose-utilizing yeasts for ethanol fermentation from lignocellulosic hydrolysates. Two IR-2-based haploid strains were selected based upon the rate of xylulose fermentation, and hybrids were obtained by mating recombinant haploid strains harboring heterogeneous xylose dehydrogenase (XDH) (wild-type NAD(+)-dependent XDH or engineered NADP(+)-dependent XDH, ARSdR), xylose reductase (XR) and xylulose kinase (XK) genes. ARSdR in the hybrids selected for growth rates on yeast extract-peptone-dextrose (YPD) agar and YP-xylose agar plates typically had a higher activity than NAD(+)-dependent XDH. Furthermore, the xylose-fermenting performance of the hybrid strain SE12 with the same level of heterogeneous XDH activity was similar to that of a recombinant strain of IR-2 harboring a single set of genes, XR/ARSdR/XK. These results suggest not only that the recombinant haploid strains retain the appropriate genetic background of IR-2 for ethanol production from xylose but also that ARSdR is preferable for xylose fermentation.

Analytical Modeling of the High Strain Rate Deformation of Polymer Matrix Composites

Science.gov (United States)

Goldberg, Robert K.; Roberts, Gary D.; Gilat, Amos

2003-01-01

The results presented here are part of an ongoing research program to develop strain rate dependent deformation and failure models for the analysis of polymer matrix composites subject to high strain rate impact loads. State variable constitutive equations originally developed for metals have been modified in order to model the nonlinear, strain rate dependent deformation of polymeric matrix materials. To account for the effects of hydrostatic stresses, which are significant in polymers, the classical 5 plasticity theory definitions of effective stress and effective plastic strain are modified by applying variations of the Drucker-Prager yield criterion. To verify the revised formulation, the shear and tensile deformation of a representative toughened epoxy is analyzed across a wide range of strain rates (from quasi-static to high strain rates) and the results are compared to experimentally obtained values. For the analyzed polymers, both the tensile and shear stress-strain curves computed using the analytical model correlate well with values obtained through experimental tests. The polymer constitutive equations are implemented within a strength of materials based micromechanics method to predict the nonlinear, strain rate dependent deformation of polymer matrix composites. In the micromechanics, the unit cell is divided up into a number of independently analyzed slices, and laminate theory is then applied to obtain the effective deformation of the unit cell. The composite mechanics are verified by analyzing the deformation of a representative polymer matrix composite (composed using the representative polymer analyzed for the correlation of the polymer constitutive equations) for several fiber orientation angles across a variety of strain rates. The computed values compare favorably to experimentally obtained results.

Job strain and the risk of stroke

DEFF Research Database (Denmark)

Fransson, Eleonor I; Nyberg, Solja T; Heikkilä, Katriina

2015-01-01

BACKGROUND AND PURPOSE: Psychosocial stress at work has been proposed to be a risk factor for cardiovascular disease. However, its role as a risk factor for stroke is uncertain. METHODS: We conducted an individual-participant-data meta-analysis of 196 380 males and females from 14 European cohort...... studies to investigate the association between job strain, a measure of work-related stress, and incident stroke. RESULTS: In 1.8 million person-years at risk (mean follow-up 9.2 years), 2023 first-time stroke events were recorded. The age- and sex-adjusted hazard ratio for job strain relative to no job....... CONCLUSION: Job strain may be associated with an increased risk of ischemic stroke, but further research is needed to determine whether interventions targeting job strain would reduce stroke risk beyond existing preventive strategies....

Development of multiple strain competitive index assays for Listeria monocytogenes using pIMC; a new site-specific integrative vector

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Cronin Michael

2008-06-01

Full Text Available Abstract Background The foodborne, gram-positive pathogen, Listeria monocytogenes, is capable of causing lethal infections in compromised individuals. In the post genomic era of L. monocytogenes research, techniques are required to identify and validate genes involved in the pathogenicity and environmental biology of the organism. The aim here was to develop a widely applicable method to tag L. monocytogenes strains, with a particular emphasis on the development of multiple strain competitive index assays. Results We have constructed a new site-specific integrative vector, pIMC, based on pPL2, for the selection of L. monocytogenes from complex samples. The pIMC vector was further modified through the incorporation of IPTG inducible markers (antibiotic and phenotypic to produce a suite of four vectors which allowed the discrimination of multiple strains from a single sample. We were able to perform murine infection studies with up to four EGDe isolates within a single mouse and showed that the tags did not impact upon growth rate or virulence. The system also allowed the identification of subtle differences in virulence between strains of L. monocytogenes commonly used in laboratory studies. Conclusion This study has developed a competitive index assay that can be broadly applied to all L. monocytogenes strains. Improved statistical robustness of the data was observed, resulting in fewer mice being required for virulence assays. The competitive index assays provide a powerful method to analyse the virulence or fitness of L. monocytogenes in complex biological samples.

Infection of inbred rat strains with Rift Valley fever virus: development of a congenic resistant strain and observations on age-dependence of resistance.

Science.gov (United States)

Anderson, G W; Rosebrock, J A; Johnson, A J; Jennings, G B; Peters, C J

1991-05-01

A congenic rat strain (WF.LEW) was derived from the susceptible Wistar-Furth (WF) (background strain) and the resistant LEW (donor strain) inbred strains and was used to evaluate the phenotypic expression of a dominant Mendelian gene that confers resistance to fatal hepatic disease caused by the ZH501 strain of Rift Valley fever virus (RVFV). Resistance to hepatic disease developed gradually with age, with full expression at approximately 10 weeks in the WF.LEW and LEW rat strains. The ZH501 strain caused fatal hepatitis in WF rats regardless of age. However, resistance to the SA75 RVFV strain (relatively non-pathogenic for adult rats), was age- and dose-dependent in both WF and LEW rats. The resistance gene transferred to the newly derived WF.LEW congenic rat strain appears to amplify age-dependent resistance of adult rats, resulting in protection against fatal hepatic disease caused by the virulent ZH501 strain. The congenic rat strain will be a valuable asset in elucidating the mechanism of resistance to Rift Valley fever virus governed by the dominant Mendelian gene.

Mechanical strain modulates age-related changes in the proliferation and differentiation of mouse adipose-derived stromal cells

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Chiang Wen-Sheng

2010-03-01

Full Text Available Abstract Background Previous studies on the effects of aging in human and mouse mesenchymal stem cells suggest that a decline in the number and differentiation potential of stem cells may contribute to aging and aging-related diseases. In this report, we used stromal cells isolated from adipose tissue (ADSCs of young (8-10 weeks, adult (5 months, and old (21 months mice to test the hypothesis that mechanical loading modifies aging-related changes in the self-renewal and osteogenic and adipogenic differentiation potential of these cells. Results We show that aging significantly reduced the proliferation and increased the adipogenesis of ADSCs, while the osteogenic potential is not significantly reduced by aging. Mechanical loading (10% cyclic stretching, 0.5 Hz, 48 h increased the subsequent proliferation of ADSCs from mice of all ages. Although the number of osteogenic colonies with calcium deposition was increased in ADSCs subjected to pre-strain, it resulted from an increase in colony number rather than from an increase in osteogenic potential after strain. Pre-strain significantly reduced the number of oil droplets and the expression of adipogenic marker genes in adult and old ADSCs. Simultaneously subjecting ADSCs to mechanical loading and adipogenic induction resulted in a stronger inhibition of adipogenesis than that caused by pre-strain. The reduction of adipogenesis by mechanical strain was loading-magnitude dependent: loading with 2% strain only resulted in a partial inhibition, and loading with 0.5% strain could not inhibit adipogenesis in ADSCs. Conclusions We demonstrate that mechanical stretching counteracts the loss of self-renewal in aging ADSCs by enhancing their proliferation and, at the same time, reduces the heightened adipogenesis of old cells. These findings are important for the further study of stem cell control and treatment for a variety of aging related diseases.

Characteristics of strain-sensitive photonic crystal cavities in a flexible substrate.

Science.gov (United States)

No, You-Shin; Choi, Jae-Hyuck; Kim, Kyoung-Ho; Park, Hong-Gyu

2016-11-14

High-index semiconductor photonic crystal (PhC) cavities in a flexible substrate support strong and tunable optical resonances that can be used for highly sensitive and spatially localized detection of mechanical deformations in physical systems. Here, we report theoretical studies and fundamental understandings of resonant behavior of an optical mode excited in strain-sensitive rod-type PhC cavities consisting of high-index dielectric nanorods embedded in a low-index flexible polymer substrate. Using the three-dimensional finite-difference time-domain simulation method, we calculated two-dimensional transverse-electric-like photonic band diagrams and the three-dimensional dispersion surfaces near the first Γ-point band edge of unidirectionally strained PhCs. A broken rotational symmetry in the PhCs modifies the photonic band structures and results in the asymmetric distributions and different levels of changes in normalized frequencies near the first Γ-point band edge in the reciprocal space, which consequently reveals strain-dependent directional optical losses and selected emission patterns. The calculated electric fields, resonant wavelengths, and quality factors of the band-edge modes in the strained PhCs show an excellent agreement with the results of qualitative analysis of modified dispersion surfaces. Furthermore, polarization-resolved time-averaged Poynting vectors exhibit characteristic dipole-like emission patterns with preferentially selected linear polarizations, originating from the asymmetric band structures in the strained PhCs.

Uniaxial Strain Induced Critical Current Degradation of Ag-Sheathed Bi-2212 Round Wire

NARCIS (Netherlands)

Dai, Chao; Qin, Jinggang; Liu, Bo; Liu, Peihang; Wu, Yu; Nijhuis, Arend; Zhou, Chao; Li, Chenshan; Hao, Qingbin; Liu, Sheng

2018-01-01

The critical current degradation of Bi-2212 Ag-sheathed round wire subjected to uniaxial strain was studied at 4.2 K in 14 T background field. The strains applied on the sample are both tension and compression. The additional tensile strain caused by the difference in thermal expansion between the

A resposta oxidativa em corações de camundongos é modulada por background genético The oxidative response of mouse hearts is modulated by genetic background

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Marco Aurélio Santos-Silva

2013-02-01

Full Text Available FUNDAMENTO: o tabagismo apresenta importante papel sobre as doenças cardiovasculares, entretanto permanecem pouco compreendidos os motivos pelos quais alguns seres humanos as desenvolvem e outros não. OBJETIVO: nosso objetivo foi analisar o perfil redox do coração de diferentes linhagens de camundongos após exposição à fumaça de cigarro. MÉTODOS: camundongos machos suíços (n = 10, C3H (n = 10, BALB/c (n = 10 e C57BL/6 (n = 10 foram expostos à fumaça de cigarro (12 cigarros/dia, enquanto os respectivos controles (n = 10 ao ar ambiente por 60 dias. Após sacrifício, o coração foi retirado para análises bioquímicas. RESULTADOS: embora o conteúdo de malondialdeído não tenha aumentado em nenhum grupo, a atividade da catalase diminuiu no grupo suíço (p BACKGROUND: Smoking plays an important role in cardiovascular diseases. However, the reasons why some individuals develop those diseases and others do not remain to be explained. OBJECTIVE: This study aimed at assessing the redox profile of the heart of different mouse strains after exposure to cigarette smoke. METHODS: Male mice of the Swiss (n = 10, C3H (n = 10, BALB/c (n = 10 and C57BL/6 (n = 10 strains were exposed to cigarette smoke (12 cigarettes/day, while their respective controls (n = 10 were exposed to ambient air for 60 days. After being euthanized, their heart was removed for biochemical analyses. RESULTS: Although the malondialdehyde content did not increase in any of the groups, catalase activity decreased in the Swiss (p < 0.05 and BALB/c (p < 0.05 strain mice as compared with their respective control groups, while myeloperoxidase decreased in the C3H (p < 0.05 and C57BL/6 (p < 0.001 strain mice as compared with their respective control groups. The reduced glutathione content decreased in the Swiss, C3H, C57BL/6 (p < 0.05 and BALB/c (p < 0,001 strain mice as compared with their respective control groups. Regarding reduced glutathione content, an increase was

Fluorogenic Strain-Promoted Alkyne-Diazo Cycloadditions.

Science.gov (United States)

Friscourt, Frédéric; Fahrni, Christoph J; Boons, Geert-Jan

2015-09-28

Fluorogenic reactions, in which non- or weakly fluorescent reagents produce highly fluorescent products, are attractive for detecting a broad range of compounds in the fields of bioconjugation and material sciences. Herein, we report that a dibenzocyclooctyne derivative modified with a cyclopropenone moiety (Fl-DIBO) can undergo fast strain-promoted cycloaddition reactions under catalyst-free conditions with azides, nitrones, nitrile oxides, as well as mono- and disubstituted diazo-derivatives. Although the reaction with nitrile oxides, nitrones, and disubstituted diazo compounds gave cycloadducts with low quantum yield, monosubstituted diazo reagents produced 1H-pyrazole derivatives that exhibited an approximately 160-fold fluorescence enhancement over Fl-DIBO combined with a greater than 10,000-fold increase in brightness. Concluding from quantum chemical calculations, fluorescence quenching of 3H-pyrazoles, which are formed by reaction with disubstituted diazo-derivatives, is likely due to the presence of energetically low-lying (n,π*) states. The fluorogenic probe Fl-DIBO was successfully employed for the labeling of diazo-tagged proteins without detectable background signal. Diazo-derivatives are emerging as attractive reporters for the labeling of biomolecules, and the studies presented herein demonstrate that Fl-DIBO can be employed for visualizing such biomolecules without the need for probe washout. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Role of scaffold network in controlling strain and functionalities of nanocomposite films.

Science.gov (United States)

Chen, Aiping; Hu, Jia-Mian; Lu, Ping; Yang, Tiannan; Zhang, Wenrui; Li, Leigang; Ahmed, Towfiq; Enriquez, Erik; Weigand, Marcus; Su, Qing; Wang, Haiyan; Zhu, Jian-Xin; MacManus-Driscoll, Judith L; Chen, Long-Qing; Yarotski, Dmitry; Jia, Quanxi

2016-06-01

Strain is a novel approach to manipulating functionalities in correlated complex oxides. However, significant epitaxial strain can only be achieved in ultrathin layers. We show that, under direct lattice matching framework, large and uniform vertical strain up to 2% can be achieved to significantly modify the magnetic anisotropy, magnetism, and magnetotransport properties in heteroepitaxial nanoscaffold films, over a few hundred nanometers in thickness. Comprehensive designing principles of large vertical strain have been proposed. Phase-field simulations not only reveal the strain distribution but also suggest that the ultimate strain is related to the vertical interfacial area and interfacial dislocation density. By changing the nanoscaffold density and dimension, the strain and the magnetic properties can be tuned. The established correlation among the vertical interface-strain-properties in nanoscaffold films can consequently be used to tune other functionalities in a broad range of complex oxide films far beyond critical thickness.

Large curvature and background scale independence in single-metric approximations to asymptotic safety

Energy Technology Data Exchange (ETDEWEB)

Morris, Tim R. [STAG Research Centre & Department of Physics and Astronomy, University of Southampton,Highfield, Southampton, SO17 1BJ (United Kingdom)

2016-11-25

In single-metric approximations to the exact renormalization group (RG) for quantum gravity, it has been not been clear how to treat the large curvature domain beyond the point where the effective cutoff scale k is less than the lowest eigenvalue of the appropriate modified Laplacian. We explain why this puzzle arises from background dependence, resulting in Wilsonian RG concepts being inapplicable. We show that when properly formulated over an ensemble of backgrounds, the Wilsonian RG can be restored. This in turn implies that solutions should be smooth and well defined no matter how large the curvature is taken. Even for the standard single-metric type approximation schemes, this construction can be rigorously derived by imposing a modified Ward identity (mWI) corresponding to rescaling the background metric by a constant factor. However compatibility in this approximation requires the space-time dimension to be six. Solving the mWI and flow equation simultaneously, new variables are then derived that are independent of overall background scale.

A replicating modified vaccinia tiantan strain expressing an avian-derived influenza H5N1 hemagglutinin induce broadly neutralizing antibodies and cross-clade protective immunity in mice.

Directory of Open Access Journals (Sweden)

Haixia Xiao

Full Text Available To combat the possibility of a zoonotic H5N1 pandemic in a timely fashion, it is necessary to develop a vaccine that would confer protection against homologous and heterologous human H5N1 influenza viruses. Using a replicating modified vaccinia virus Tian Tan strain (MVTT as a vaccine vector, we constructed MVTTHA-QH and MVTTHA-AH, which expresses the H5 gene of a goose-derived Qinghai strain A/Bar-headed Goose/Qinghai/1/2005 or human-derived Anhui Strain A/Anhui/1/2005. The immunogenicity profiles of both vaccine candidates were evaluated. Vaccination with MVTTHA-QH induced a significant level of neutralizing antibodies (Nabs against a homologous strain and a wide range of H5N1 pseudoviruses (clades 1, 2.1, 2.2, 2.3.2, and 2.3.4. Neutralization tests (NT and Haemagglutination inhibition (HI antibodies inhibit the live autologous virus as well as a homologous A/Xingjiang/1/2006 and a heterologous A/Vietnam/1194/2004, representing two human isolates from clade 2.2 and clade 1, respectively. Importantly, mice vaccinated with intranasal MVTTHA-QH were completely protected from challenge with lethal dosages of A/Bar-headed Goose/Qinghai/1/2005 and the A/Viet Nam/1194/2004, respectively, but not control mice that received a mock MVTTS vaccine. However, MVTTHA-AH induced much lower levels of NT against its autologous strain. Our results suggest that it is feasible to use the H5 gene from A/Bar-headed Goose/Qinghai/1/2005 to construct an effective vaccine, when using MVTT as a vector, to prevent infections against homologous and genetically divergent human H5N1 influenza viruses.

Dynamical x-ray diffraction studies of interfacial strain in superlattices grown by molecular beam epitaxy

International Nuclear Information System (INIS)

Vandenberg, J.M.; Chu, S.N.G.; Hamm, R.A.; Panish, M.B.; Ritter, D.; Mancrander, A.T.

1992-01-01

This paper reports on dynamical X-ray diffraction studies that have been carried out for lattice-matched InGaAs/InP superlattices grown by modified molecular beam epitaxy (MBE) techniques. The (400) X-ray satellite pattern, which is predominantly affected by the strain modulation, was analyzed. The strain and thickness of the actual layers including the presence of strained interfacial regions were determined

Manufacturing and Shear Response Characterization of Carbon Nanofiber Modified CFRP Using the Out-of-Autoclave-Vacuum-Bag-Only Cure Process

Science.gov (United States)

McDonald, Erin E.; Wallace, Landon F.; Hickman, Gregory J. S.; Hsiao, Kuang-Ting

2014-01-01

The interlaminar shear response is studied for carbon nanofiber (CNF) modified out-of-autoclave-vacuum-bag-only (OOA-VBO) carbon fiber reinforced plastic (CFRP). Commercial OOA-VBO prepregs were coated with a CNF modified epoxy solution and a control epoxy solution without CNF to make CNF modified samples and control samples, respectively. Tensile testingwas used to study the in-plane shear performance of [±45°]4s composite laminates. Significant difference in failure modes between the control and CNF modified CFRPs was identified. The control samples experienced half-plane interlaminar delamination, whereas the CNF modified samples experienced a localized failure in the intralaminar region. Digital image correlation (DIC) surface strain results of the control sample showed no further surface strain increase along the delaminated section when the sample was further elongated prior to sample failure. On the other hand, the DIC results of the CNF modified sample showed that the surface strain increased relatively and uniformly across the CFRP as the sample was further elongated until sample failure. The failure mode evidence along with microscope pictures indicated that the CNF modification acted as a beneficial reinforcement inhibiting interlaminar delamination. PMID:24688435

Manufacturing and Shear Response Characterization of Carbon Nanofiber Modified CFRP Using the Out-of-Autoclave-Vacuum-Bag-Only Cure Process

Directory of Open Access Journals (Sweden)

Erin E. McDonald

2014-01-01

Full Text Available The interlaminar shear response is studied for carbon nanofiber (CNF modified out-of-autoclave-vacuum-bag-only (OOA-VBO carbon fiber reinforced plastic (CFRP. Commercial OOA-VBO prepregs were coated with a CNF modified epoxy solution and a control epoxy solution without CNF to make CNF modified samples and control samples, respectively. Tensile testingwas used to study the in-plane shear performance of [±45°]4s composite laminates. Significant difference in failure modes between the control and CNF modified CFRPs was identified. The control samples experienced half-plane interlaminar delamination, whereas the CNF modified samples experienced a localized failure in the intralaminar region. Digital image correlation (DIC surface strain results of the control sample showed no further surface strain increase along the delaminated section when the sample was further elongated prior to sample failure. On the other hand, the DIC results of the CNF modified sample showed that the surface strain increased relatively and uniformly across the CFRP as the sample was further elongated until sample failure. The failure mode evidence along with microscope pictures indicated that the CNF modification acted as a beneficial reinforcement inhibiting interlaminar delamination.

Manufacturing and shear response characterization of carbon nanofiber modified CFRP using the out-of-autoclave-vacuum-bag-only cure process.

Science.gov (United States)

McDonald, Erin E; Wallace, Landon F; Hickman, Gregory J S; Hsiao, Kuang-Ting

2014-01-01

The interlaminar shear response is studied for carbon nanofiber (CNF) modified out-of-autoclave-vacuum-bag-only (OOA-VBO) carbon fiber reinforced plastic (CFRP). Commercial OOA-VBO prepregs were coated with a CNF modified epoxy solution and a control epoxy solution without CNF to make CNF modified samples and control samples, respectively. Tensile testing was used to study the in-plane shear performance of [± 45°]4s composite laminates. Significant difference in failure modes between the control and CNF modified CFRPs was identified. The control samples experienced half-plane interlaminar delamination, whereas the CNF modified samples experienced a localized failure in the intralaminar region. Digital image correlation (DIC) surface strain results of the control sample showed no further surface strain increase along the delaminated section when the sample was further elongated prior to sample failure. On the other hand, the DIC results of the CNF modified sample showed that the surface strain increased relatively and uniformly across the CFRP as the sample was further elongated until sample failure. The failure mode evidence along with microscope pictures indicated that the CNF modification acted as a beneficial reinforcement inhibiting interlaminar delamination.

Evaluation of a genetically modified foot-and-mouth disease virus vaccine candidate generated by reverse genetics

Science.gov (United States)

2012-01-01

Background Foot-and-mouth disease (FMD) is the most economically important and highly contagious disease of cloven-hoofed animals worldwide. Control of the disease has been mainly based on large-scale vaccinations with whole-virus inactivated vaccines. In recent years, a series of outbreaks of type O FMD occurred in China (including Chinese Taipei, Chinese Hong Kong) posed a tremendous threat to Chinese animal husbandry. Its causative agent, type O FMDV, has evolved into three topotypes (East–South Asia (ME-SA), Southeast Asia (SEA), Cathay (CHY)) in these regions, which represents an important obstacle to disease control. The available FMD vaccine in China shows generally good protection against ME-SA and SEA topotype viruses infection, but affords insufficient protection against some variants of the CHY topotype. Therefore, the choice of a new vaccine strain is of fundamental importance. Results The present study describes the generation of a full-length infectious cDNA clone of FMDV vaccine strain and a genetically modified virus with some amino acid substitutions in antigenic sites 1, 3, and 4, based on the established infectious clone. The recombinant viruses had similar growth properties to the wild O/HN/CHA/93 virus. All swine immunized with inactivated vaccine prepared from the O/HN/CHA/93 were fully protected from challenge with the viruses of ME-SA and SEA topotypes and partially protected against challenge with the virus of CHY topotype at 28 days post-immunization. In contrast, the swine inoculated with the genetically modified vaccine were completely protected from the infection of viruses of the three topotypes. Conclusions Some amino acid substitutions in the FMDV vaccine strain genome did not have an effect on the ability of viral replication in vitro. The vaccine prepared from genetically modified FMDV by reverse genetics significantly improved the protective efficacy to the variant of the CHY topotype, compared with the wild O/HN/CHA/93 virus

Evaluation of a genetically modified foot-and-mouth disease virus vaccine candidate generated by reverse genetics

Directory of Open Access Journals (Sweden)

Li Pinghua

2012-05-01

Full Text Available Abstract Background Foot-and-mouth disease (FMD is the most economically important and highly contagious disease of cloven-hoofed animals worldwide. Control of the disease has been mainly based on large-scale vaccinations with whole-virus inactivated vaccines. In recent years, a series of outbreaks of type O FMD occurred in China (including Chinese Taipei, Chinese Hong Kong posed a tremendous threat to Chinese animal husbandry. Its causative agent, type O FMDV, has evolved into three topotypes (East–South Asia (ME-SA, Southeast Asia (SEA, Cathay (CHY in these regions, which represents an important obstacle to disease control. The available FMD vaccine in China shows generally good protection against ME-SA and SEA topotype viruses infection, but affords insufficient protection against some variants of the CHY topotype. Therefore, the choice of a new vaccine strain is of fundamental importance. Results The present study describes the generation of a full-length infectious cDNA clone of FMDV vaccine strain and a genetically modified virus with some amino acid substitutions in antigenic sites 1, 3, and 4, based on the established infectious clone. The recombinant viruses had similar growth properties to the wild O/HN/CHA/93 virus. All swine immunized with inactivated vaccine prepared from the O/HN/CHA/93 were fully protected from challenge with the viruses of ME-SA and SEA topotypes and partially protected against challenge with the virus of CHY topotype at 28 days post-immunization. In contrast, the swine inoculated with the genetically modified vaccine were completely protected from the infection of viruses of the three topotypes. Conclusions Some amino acid substitutions in the FMDV vaccine strain genome did not have an effect on the ability of viral replication in vitro. The vaccine prepared from genetically modified FMDV by reverse genetics significantly improved the protective efficacy to the variant of the CHY topotype, compared with the

Confinining properties of QCD in strong magnetic backgrounds

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Bonati Claudio

2017-01-01

Full Text Available Strong magnetic backgrounds are known to modify QCD properties at a nonperturbative level. We discuss recent lattice results, obtained for Nf = 2 + 1 QCD with physical quark masses, concerning in particular the modifications and the anisotropies induced at the level of the static quark-antiquark potential, both at zero and finite temperature.

Effect of Genetically Modified Pseudomonas putida WCS358r on the Fungal Rhizosphere Microflora of Field-Grown Wheat

NARCIS (Netherlands)

Glandorf, D.C.M.; Verheggen, Patrick; Jansen, Timo; Jorritsma, J.-W.; Smit, Eric; Leeflang, Paula; Wernars, Karel; Thomashow, L.S.; Laureijs, Eric; Thomas-Oates, J.E.; Bakker, P.A.H.M.; Loon, L.C. van

2001-01-01

We released genetically modified Pseudomonas putida WCS358r into the rhizospheres of wheat plants. The two genetically modified derivatives, genetically modified microorganism (GMM) 2 and GMM 8, carried the phz biosynthetic gene locus of strain P. fluorescens 2-79 and constitutively produced the

Dual strain mechanisms in a lead-free morphotropic phase boundary ferroelectric

DEFF Research Database (Denmark)

Walker, Julian; Simons, Hugh; Alikin, Denis O

2016-01-01

Electromechanical properties such as d33 and strain are significantly enhanced at morphotropic phase boundaries (MPBs) between two or more different crystal structures. Many actuators, sensors and MEMS devices are therefore systems with MPBs, usually between polar phases in lead (Pb)-based ferroe......Electromechanical properties such as d33 and strain are significantly enhanced at morphotropic phase boundaries (MPBs) between two or more different crystal structures. Many actuators, sensors and MEMS devices are therefore systems with MPBs, usually between polar phases in lead (Pb......)-based ferroelectric ceramics. In the search for Pb-free alternatives, systems with MPBs between polar and non-polar phases have recently been theorized as having great promise. While such an MPB was identified in rare-earth (RE) modified bismuth ferrite (BFO) thin films, synthesis challenges have prevented its...... realization in ceramics. Overcoming these, we demonstrate a comparable electromechanical response to Pb-based materials at the polar-to-non-polar MPB in Sm modified BFO. This arises from 'dual' strain mechanisms: ferroelectric/ferroelastic switching and a previously unreported electric-field induced...

Strain Tuning of the Charge Density Wave in Monolayer and Bilayer 1T-TaS2

KAUST Repository

Gan, Liyong; Zhang, Lihong; Zhang, Qingyun; Guo, Chunsheng; Schwingenschlö gl, Udo; Zhao, Yong

2015-01-01

By first-principles calculations, we investigate the strain effects on the charge density wave states of monolayer and bilayer 1T-TaS2. The modified stability of the charge density wave in the monolayer is understood in terms of the strain dependent

A Modified Constitutive Model for Tensile Flow Behaviors of BR1500HS Ultra-High-Strength Steel at Medium and Low Temperature Regions

Science.gov (United States)

Zhao, Jun; Quan, Guo-Zheng; Pan, Jia; Wang, Xuan; Wu, Dong-Sen; Xia, Yu-Feng

2018-01-01

Constitutive model of materials is one of the most requisite mathematical model in the finite element analysis, which describes the relationships of flow behaviors with strain, strain rate and temperature. In order to construct such constitutive relationships of ultra-high-strength BR1500HS steel at medium and low temperature regions, the true stress-strain data over a wide temperature range of 293-873 K and strain rate range of 0.01-10 s-1 were collected from a series of isothermal uniaxial tensile tests. The experimental results show that stress-strain relationships are highly non-linear and susceptible to three parameters involving temperature, strain and strain rate. By considering the impacts of strain rate and temperature on strain hardening, a modified constitutive model based on Johnson-Cook model was proposed to characterize flow behaviors in medium and low temperature ranges. The predictability of the improved model was also evaluated by the relative error (W(%)), correlation coefficient (R) and average absolute relative error (AARE). The R-value and AARE-value for modified constitutive model at medium and low temperature regions are 0.9915 & 1.56 % and 0.9570 & 5.39 %, respectively, which indicates that the modified constitutive model can precisely estimate the flow behaviors for BR1500HS steel in the medium and low temperature regions.

Clostridium botulinum strains producing BoNT/F4 or BoNT/F5.

Science.gov (United States)

Raphael, Brian H; Bradshaw, Marite; Kalb, Suzanne R; Joseph, Lavin A; Lúquez, Carolina; Barr, John R; Johnson, Eric A; Maslanka, Susan E

2014-05-01

Botulinum neurotoxin type F (BoNT/F) may be produced by Clostridium botulinum alone or in combination with another toxin type such as BoNT/A or BoNT/B. Type F neurotoxin gene sequences have been further classified into seven toxin subtypes. Recently, the genome sequence of one strain of C. botulinum (Af84) was shown to contain three neurotoxin genes (bont/F4, bont/F5, and bont/A2). In this study, eight strains containing bont/F4 and seven strains containing bont/F5 were examined. Culture supernatants produced by these strains were incubated with BoNT/F-specific peptide substrates. Cleavage products of these peptides were subjected to mass spectral analysis, allowing detection of the BoNT/F subtypes present in the culture supernatants. PCR analysis demonstrated that a plasmid-specific marker (PL-6) was observed only among strains containing bont/F5. Among these strains, Southern hybridization revealed the presence of an approximately 242-kb plasmid harboring bont/F5. Genome sequencing of four of these strains revealed that the genomic backgrounds of strains harboring either bont/F4 or bont/F5 are diverse. None of the strains analyzed in this study were shown to produce BoNT/F4 and BoNT/F5 simultaneously, suggesting that strain Af84 is unusual. Finally, these data support a role for the mobility of a bont/F5-carrying plasmid among strains of diverse genomic backgrounds.

Modeling Lost-Particle Accelerator Backgrounds in PEP-II Using LPTURTLE

CERN Document Server

Fieguth, Theodore; Kozanecki, Witold

2005-01-01

Background studies during the design, construction, commissioning, operation and improvement of BaBar and PEP-II have been greatly influenced by results from a program referred to as LPTURTLE (Lost Particle TURTLE a modified version of Decay TURTLE) which was originally conceived for the purpose of studying gas background for SLC. This venerable program is still in use today. We describe its use, capabilities and improvements and refer to current results now being applied to BaBar.

Characterization of Shigella Strains by Plasmid Profile Analysis and Antibiotic Susceptibility Patterns in a Pediatric Hospital in Ahvaz

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Amin Sakhaei

2015-11-01

Full Text Available Background: High incidences of dysentery and diarrhea were reported in a pediatric hospital in Ahvaz, Iran during March to April, 2013. Objectives: A cross-sectional study was therefore undertaken to identify the causative agents. Patients and Methods: A total of 230 diarrhea samples were collected from the patients and analyzed by routine bacteriological methods. Bacterial identification, serological assay, antimicrobial susceptibility testing, extended spectrum β-lactamases (ESBLs screening and plasmid profile analysis were performed according to the standard guidelines. Results: A total of 70 Shigella strains including %70 (n = 49 S. sonnei and 30% (n = 21 S. flexneri were isolated from diarrhea samples. Most of the Shigella isolates showed high degrees of resistance to ampicillin, ulafamethoxazole- trimethoprime and cefexim. Concurrent resistance to sulafametoxazole- trimethoprime and ampicillin was the most common resistance pattern. Overall, 11.4% of Shigella isolates showed the ESBL producer criteria. The plasmid profile patterns of all the strains were determined by a modified alkaline lysis method. By plasmid profile analysis 23 genotypes were identified among all the isolates, 14 and 9 genotypes among the S. sonnei and S. Flexneri respectively. S. sonnei and S. flexneri isolates demonstrated unique plasmid profiles. Conclusions: These data demonstrated that S. sonnei strains are the main cause of shigellosis as the prevalent Shigella serotype in Iran. We also found that the antibiotic resistance rates are increasing among Shigella strains. Plasmid profile analysis is more reliable than antibiotic susceptibility patterns in epidemiologic studies.

Numerical analysis of standard and modified osteosynthesis in long bone fractures treatment.

Science.gov (United States)

Sisljagić, Vladimir; Jovanović, Savo; Mrcela, Tomislav; Radić, Radivoje; Selthofer, Robert; Mrcela, Milanka

2010-03-01

The fundamental problem in osteoporotic fracture treatment is significant decrease in bone mass and bone tissue density resulting in decreased firmness and elasticity of osteoporotic bone. Application of standard implants and standard surgical techniques in osteoporotic bone fracture treatment makes it almost impossible to achieve stable osteosynthesis sufficient for early mobility, verticalization and load. Taking into account the form and the size of the contact surface as well as distribution of forces between the osteosynthetic materials and the bone tissue numerical analysis showed advantages of modified osteosynthesis with bone cement filling in the screw bed. The applied numerical model consisted of three sub-models: 3D model from solid elements, 3D cross section of the contact between the plate and the bone and the part of 3D cross section of the screw head and body. We have reached the conclusion that modified osteosynthesis with bone cement resulted in weaker strain in the part of the plate above the fracture fissure, more even strain on the screws, plate and bone, more even strain distribution along all the screws' bodies, significantly greater strain in the part of the screw head opposite to the fracture fissure, firm connection of the screw head and neck and the plate hole with the whole plate and more even bone strain around the screw.

Evolution of microstructure, strain and physical properties in oxide nanocomposite films.

Science.gov (United States)

Chen, Aiping; Weigand, Marcus; Bi, Zhenxing; Zhang, Wenrui; Lü, Xuejie; Dowden, Paul; MacManus-Driscoll, Judith L; Wang, Haiyan; Jia, Quanxi

2014-06-24

We, using LSMO:ZnO nanocomposite films as a model system, have studied the effect of film thickness on the physical properties of nanocomposites. It shows that strain, microstructure, as well as magnetoresistance strongly rely on film thickness. The magnetotransport properties have been fitted by a modified parallel connection channel model, which is in agreement with the microstructure evolution as a function of film thickness in nanocomposite films on sapphire substrates. The strain analysis indicates that the variation of physical properties in nanocomposite films on LAO is dominated by strain effect. These results confirm the critical role of film thickness on microstructures, strain states, and functionalities. It further shows that one can use film thickness as a key parameter to design nanocomposites with optimum functionalities.

The effect of hamstring flexibility on peak hamstring muscle strain in sprinting

OpenAIRE

Xianglin Wan; Feng Qu; William E. Garrett; Hui Liu; Bing Yu

2017-01-01

Background: The effect of hamstring flexibility on the peak hamstring muscle strains in sprinting, until now, remained unknown, which limited our understanding of risk factors of hamstring muscle strain injury (hamstring injury). As a continuation of our previous study, this study was aimed to examine the relationship between hamstring flexibility and peak hamstring muscle strains in sprinting. Methods: Ten male and 10 female college students participated in this study. Hamstring flexibili...

Phenotypic and genotypic characterization of Klebsiella pneumoniae strains with reduced susceptibiliy to carbapenems

Directory of Open Access Journals (Sweden)

Simone Ambretti

2009-12-01

Full Text Available Reduced susceptibility to carbapenems in Gram-negative pathogens is an emerging feature of the antibiotic-resistance phenomenom Reports about strains resistant to this class of antibiotics among Enterobacteriaceae, particularly in Klebsiella pneumoniae, are increasing.The aims of this study were to assess the incidence of Klebsiella pneumoniae with reduced susceptibility to carbapenems in Bologna area and to carry out the characterization of these strains.The study included isolates of K. pneumoniae that showed reduced susceptibility to carbapenems, as detected by an automated system (Vitek2, bioMérieux. Between January and May 2009, 26 strains were collected (mainly isolated from urinary samples.These isolates were tested for susceptibility to carbapenems by E-test, to define MIC values for meropenem and ertapenem. Moreover, to detect the production of metallo-beta lactamases (MBL and carbapenemases (KPC were respectively performed the Etest with imipenem and imipenem/EDTA (IPM-IPM/EDTA and the modified Hodge test. Susceptibility assays performed by E-test showed that 25/26 strains were susceptible to meropenem, while for ertapenem 20/26 strains resulted resistant.The modified Hodge test was positive for 1 strain, while all the isolates were negative to the IPM-IPM/EDTA E-test.These results show that, as recently reported, the majority of strains of K. pneumoniae exhibiting reduced susceptibility to carbapenems, especially to ertapenem, are characterized by the production of ESBLs, which likely is associated with the loss of porins. On the other side, one strain was found to produce KPC and this finding confirms that the diffusion of carbapenemases producing K. pneumoniae has also to be considered in this geographic area.

Hydrogen production by using Rhodobacter capsulatus mutants with genetically modified electron transfer chains

Energy Technology Data Exchange (ETDEWEB)

OEztuerk, Yavuz; Yuecel, Meral; Guenduez, Ufuk [Department of Biology, Middle East Technical University, Ankara (Turkey); Daldal, Fevzi [Department of Biology, Plant Science Institute, University of Pennsylvania, Philadelphia, PA 19104-6018 (United States); Mandaci, Sevnur [TUEBITAK Research Institute for Genetic Engineering and Biotechnology, Gebze Kocaeli 41470 (Turkey); Tuerker, Lemi [Department of Chemistry, Middle East Technical University, Ankara (Turkey); Eroglu, Inci [Department of Chemical Engineering, Middle East Technical University, Ankara (Turkey)

2006-09-15

In Rhodobacter capsulatus excess reducing equivalents generated by organic acid oxidation is consumed to reduce protons into hydrogen by the activity of nitrogenase. Nitrogenase serves as a redox-balancing tool and is activated by the RegB/RegA global regulatory system during photosynthetic growth. The terminal cytochrome cbb{sub 3} oxidase and the redox state of the cyclic photosynthetic electron transfer chain serve redox signaling to the RegB/RegA regulatory systems in Rhodobacter. In this study, hydrogen production of various R. capsulatus strains harboring the genetically modified electron carrier cytochromes or lacking the cyt cbb{sub 3} oxidase or the quinol oxidase were compared with the wild type. The results indicated that hydrogen production of mutant strains with modified electron carrier cytochromes decreased 3- to 4-fold, but the rate of hydrogen production increased significantly in a cbb{sub 3}{sup -} mutant. Moreover, hydrogen production efficiency of various R. capsulatus strains further increased by inactivation of uptake hydrogenase genes. (author)

The impact of pneumolysin on the macrophage response to Streptococcus pneumoniae is strain-dependent.

Directory of Open Access Journals (Sweden)

Richard M Harvey

Full Text Available Streptococcus pneumoniae is the world's leading cause of pneumonia, bacteremia, meningitis and otitis media. A major pneumococcal virulence factor is the cholesterol-dependent cytolysin, which has the defining property of forming pores in cholesterol-containing membranes. In recent times a clinically significant and internationally successful serotype 1 ST306 clone has been found to express a non-cytolytic variant of Ply (Ply306. However, while the pneumococcus is a naturally transformable organism, strains of the ST306 clonal group have to date been virtually impossible to transform, severely restricting efforts to understand the role of non-cytolytic Ply in the success of this clone. In this study isogenic Ply mutants were constructed in the D39 background and for the first time in the ST306 background (A0229467 to enable direct comparisons between Ply variants for their impact on the immune response in a macrophage-like cell line. Strains that expressed cytolytic Ply were found to induce a significant increase in IL-1β release from macrophage-like cells compared to the non-cytolytic and Ply-deficient strains in a background-independent manner, confirming the requirement for pore formation in the Ply-dependent activation of the NLRP3 inflammasome. However, cytolytic activity in the D39 background was found to induce increased expression of the genes encoding GM-CSF (CSF2, p19 subunit of IL-23 (IL23A and IFNβ (IFNB1 compared to non-cytolytic and Ply-deficient D39 mutants, but had no effect in the A0229467 background. The impact of Ply on the immune response to the pneumococcus is highly dependent on the strain background, thus emphasising the importance of the interaction between specific virulence factors and other components of the genetic background of this organism.

Societal aspects of genetically modified foods

DEFF Research Database (Denmark)

Frewer, L.J.; Lassen, J.; Kettlitz, B.

2004-01-01

This paper aims to examine some of the reasons behind public controversy associated with the introduction of genetically modified foods in Europe the 1990s. The historical background to the controversy is provided to give context. The issue of public acceptance of genetically modified foods......, and indeed the emerging biosciences more generally, is considered in the context of risk perceptions and attitudes, public trust in regulatory institutions, scientists and industry, and the need to develop communication strategies that explicitly include public concerns rather than exclude them. Increased...

Achieving high aspect ratio wrinkles by modifying material network stress.

Science.gov (United States)

Chen, Yu-Cheng; Wang, Yan; McCarthy, Thomas J; Crosby, Alfred J

2017-06-07

Wrinkle aspect ratio, or the amplitude divided by the wavelength, is hindered by strain localization transitions when an increasing global compressive stress is applied to synthetic material systems. However, many examples from living organisms show extremely high aspect ratios, such as gut villi and flower petals. We use three experimental approaches to demonstrate that these high aspect ratio structures can be achieved by modifying the network stress in the wrinkle substrate. We modify the wrinkle stress and effectively delay the strain localization transition, such as folding, to larger aspect ratios by using a zero-stress initial wavy substrate, creating a secondary network with post-curing, or using chemical stress relaxation materials. A wrinkle aspect ratio as high as 0.85, almost three times higher than common values of synthetic wrinkles, is achieved, and a quantitative framework is presented to provide understanding the different strategies and predictions for future investigations.

Biosorption of cadmium by Brevundimonas sp. ZF12 strain, a novel biosorbent isolated from hot-spring waters in high background radiation areas

International Nuclear Information System (INIS)

Masoudzadeh, Nasrin; Zakeri, Fardideh; Lotfabad, Tayebe bagheri; Sharafi, Hakimeh; Masoomi, Fatemeh; Zahiri, Hoseein Shahbani; Ahmadian, Gholamreza; Noghabi, Kambiz Akbari

2011-01-01

Highlights: ► Isolation and characterization of a novel cadmium-biosorbent (Brevundimonas sp. ZF12) from high background radiation areas. ► Brevundimonas sp. ZF12 caused 50% removal of cadmium at the concentration level of 250 ppm. ► Solution pH values used for the reusability study have powerful desorptive features to recover Cd ions sorbed onto the biomass. ► This is the first study carried out so far for the cadmium removal from aqueous solutions by a novel biosorbent Brevundimonas sp. ZF12. ► In our opinion, the isolate can be an attractive alternative to remove the cadmium-containing wastewaters. - Abstract: The aim of this study is to screen cadmium biosorbing bacterial strains isolated from soils and hot-springs containing high concentrations of radium ( 226 Ra) in Ramsar using a batch system. Brevundimonas sp. ZF12 strain isolated from the water with high 226 Ra content caused 50% removal of cadmium at a concentration level of 250 ppm. The biosorption equilibrium data are fitted well by the Langmuir adsorption isotherm and kinetic studies indicated that the biosorption follows pseudo second-order model. The effect of different physico-chemical parameters like biomass concentration, pH, cadmium concentration, temperature and contact time on cadmium sorption was also investigated using FTIR, SEM and XRD analytical techniques. A high desorption efficiency (above 90%) was obtained using a pH range of 2.0–4.0. Reusability of the biomass was examined under consecutive biosorption–desorption cycles repeated thrice. In conclusion, Brevundimonas sp. ZF12 is proposed as an excellent cadmium biosorbent that may have important applications in Cd removal from wastewaters.

Duality invariant class of exact string backgrounds

CERN Document Server

Klimcík, C

1994-01-01

We consider a class of $2+D$ - dimensional string backgrounds with a target space metric having a covariantly constant null Killing vector and flat `transverse' part. The corresponding sigma models are invariant under $D$ abelian isometries and are transformed by $O(D,D)$ duality into models belonging to the same class. The leading-order solutions of the conformal invariance equations (metric, antisymmetric tensor and dilaton), as well as the action of $O(D,D)$ duality transformations on them, are exact, i.e. are not modified by $\\a'$-corrections. This makes a discussion of different space-time representations of the same string solution (related by $O(D,D|Z)$ duality subgroup) rather explicit. We show that the $O(D,D)$ duality may connect curved $2+D$-dimensional backgrounds with solutions having flat metric but, in general, non-trivial antisymmetric tensor and dilaton. We discuss several particular examples including the $2+D=4$ - dimensional background that was recently interpreted in terms of a WZW model.

Strain-effect transistors: Theoretical study on the effects of external strain on III-nitride high-electron-mobility transistors on flexible substrates

Energy Technology Data Exchange (ETDEWEB)

Shervin, Shahab; Asadirad, Mojtaba [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204-4006 (United States); Materials Science and Engineering Program, University of Houston, Houston, Texas 77204 (United States); Kim, Seung-Hwan; Ravipati, Srikanth; Lee, Keon-Hwa [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204-4006 (United States); Bulashevich, Kirill [STR Group, Inc., Engels av. 27, P.O. Box 89, 194156, St. Petersburg (Russian Federation); Ryou, Jae-Hyun, E-mail: jryou@uh.edu [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204-4006 (United States); Materials Science and Engineering Program, University of Houston, Houston, Texas 77204 (United States); Texas Center for Superconductivity at the University of Houston (TcSUH), University of Houston, Houston, Texas 77204 (United States)

2015-11-09

This paper presents strain-effect transistors (SETs) based on flexible III-nitride high-electron-mobility transistors (HEMTs) through theoretical calculations. We show that the electronic band structures of InAlGaN/GaN thin-film heterostructures on flexible substrates can be modified by external bending with a high degree of freedom using polarization properties of the polar semiconductor materials. Transfer characteristics of the HEMT devices, including threshold voltage and transconductance, are controlled by varied external strain. Equilibrium 2-dimensional electron gas (2DEG) is enhanced with applied tensile strain by bending the flexible structure with the concave-side down (bend-down condition). 2DEG density is reduced and eventually depleted with increasing compressive strain in bend-up conditions. The operation mode of different HEMT structures changes from depletion- to enchantment-mode or vice versa depending on the type and magnitude of external strain. The results suggest that the operation modes and transfer characteristics of HEMTs can be engineered with an optimum external bending strain applied in the device structure, which is expected to be beneficial for both radio frequency and switching applications. In addition, we show that drain currents of transistors based on flexible InAlGaN/GaN can be modulated only by external strain without applying electric field in the gate. The channel conductivity modulation that is obtained by only external strain proposes an extended functional device, gate-free SETs, which can be used in electro-mechanical applications.

Neutralization of X4- and R5-tropic HIV-1 NL4-3 variants by HOCl-modified serum albumins

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Schwalbe Birco

2010-06-01

Full Text Available Abstract Background Myeloperoxidase (MPO, an important element of the microbicidal activity of neutrophils, generates hypochlorous acid (HOCl from H2O2 and chloride, which is released into body fluids. Besides its direct microbicidal activity, HOCl can react with amino acid residues and HOCl-modified proteins can be detected in vivo. Findings This report is based on binding studies of HOCl-modified serum albumins to HIV-1 gp120 and three different neutralization assays using infectious virus. The binding studies were carried out by surface plasmon resonance spectroscopy and by standard ELISA techniques. Virus neutralization assays were carried out using HIV-1 NL4-3 virus and recombinant strains with CXCR4 and CCR5 coreceptor usage. Viral infection was monitored by a standard p24 or X-gal staining assay. Our data demonstrate that HOCl-modified mouse-, bovine- and human serum albumins all bind to the HIV-1 NL4-3 gp120 (LAV glycoprotein in contrast to non-modified albumin. Binding of HOCl-modified albumin to gp120 correlated to the blockade of CD4 as well as that of V3 loop specific monoclonal antibody binding. In neutralization experiments, HOCl-modified serum albumins inhibited replication and syncytium formation of the X4- and R5-tropic NL4-3 isolates in a dose dependent manner. Conclusions Our data indicate that HOCl-modified serum albumin veils the binding site for CD4 and the V3 loop on gp120. Such masking of the viral gp120/gp41 envelope complex might be a simple but promising strategy to inactivate HIV-1 and therefore prevent infection when HOCl-modified serum albumin is applied, for example, as a topical microbicide.

new concepts of a modified hall - petch type relationship

African Journals Online (AJOL)

NIJOTECH

Abstract. A modified form of the Hall - Perch equation, where the average grain diameter is replaced by the surface to volume ratio of internal boundaries (Sv), is considered. Working with this model, a flow stress – Sv relationship dominated by geometrically necessary dislocations (GNDs) is derived for the low strain region.

Stress-Softening and Residual Strain Effects in Suture Materials

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Alex Elías-Zúñiga

2013-01-01

Full Text Available This work focuses on the experimental characterization of suture material samples of MonoPlus, Monosyn, polyglycolic acid, polydioxanone 2–0, polydioxanone 4–0, poly(glycolide-co-epsilon-caprolactone, nylon, and polypropylene when subjected to cyclic loading and unloading conditions. It is found that all tested suture materials exhibit stress-softening and residual strain effects related to the microstructural material damage upon deformation from the natural, undistorted state of the virgin suture material. To predict experimental observations, a new constitutive material model that takes into account stress-softening and residual strain effects is developed. The basis of this model is the inclusion of a phenomenological nonmonotonous softening function that depends on the strain intensity between loading and unloading cycles. The theory is illustrated by modifying the non-Gaussian average-stretch, full-network model to capture stress-softening and residual strains by using pseudoelasticity concepts. It is shown that results obtained from theoretical simulations compare well with suture material experimental data.

Multiaxial Stress-Strain Modeling and Effect of Additional Hardening due to Nonproportional Loading

International Nuclear Information System (INIS)

Rashed, G.; Ghajar, R.; Farrahi, G.

2007-01-01

Most engineering components are subjected to multiaxial rather than uniaxial cyclic loading, which causes multiaxial fatigue. The pre-requisite to predict the fatigue life of such components is to determine the multiaxial stress strain relationship. In this paper the multiaxial cyclic stress-strain model under proportional loading is derived using the modified power law stress-strain relationship. The equivalent strain amplitude consisted of the normal strain excursion and maximum shear strain amplitude is used in the proportional model to include the additional hardening effect due to nonproportional loading. Therefore a new multiaxial cyclic stress-strain relationship is devised for out of phase nonproportional loading. The model is applied to the nonproportional loading case and the results are compared with the other researchers' experimental data published in the literature, which are in a reasonable agreement with the experimental data. The relationship presented here is convenient for the engineering applications

Construction of Escherichia coli Mutant with Decreased Endotoxic Activity by Modifying Lipid A Structure

Directory of Open Access Journals (Sweden)

Qiong Liu

2015-05-01

Full Text Available Escherichia coli BL21 (DE3 and its derivatives are widely used for the production of recombinant proteins, but these purified proteins are always contaminated with lipopolysaccharide (LPS. LPS is recognized by the toll-like receptor 4 and myeloid differentiation factor 2 complex of mammalian immune cells and leads to release of pro-inflammatory cytokines. It is a vital step to remove LPS from the proteins before use for therapeutic purpose. In this study, we constructed BL21 (DE3 ∆msbB28 ∆pagP38 mutant, which produces a penta-acylated LPS with reduced endotoxicity. The plasmids harboring pagL and/or lpxE were then introduced into this mutant to further modify the LPS. The new strain (S004 carrying plasmid pQK004 (pagL and lpxE produced mono-phosphoryated tetra-acylated lipid A, which induces markedly less production of tumor necrosis factor-α in the RAW264.7 and IL-12 in the THP1, but still retains ability to produce recombinant proteins. This study provides a strategy to decrease endotoxic activity of recombinant proteins purified from E. coli BL21 backgrounds and a feasible approach to modify lipid A structure for alternative purposes such as mono-phosphoryl lipid A (MPL as vaccine adjuvants.

Strain distributions in nano-onions with uniform and non-uniform compositions

International Nuclear Information System (INIS)

Duan, H L; Karihaloo, B L; Wang, J; Yi, X

2006-01-01

Nano-onions are ellipsoidal or spherical particles consisting of a core surrounded by concentric shells of nanometre size. Nano-onions produced by self-assembly and colloidal techniques have different structures and compositions, and thus differ in the state of strains. The mismatch of the thermal expansion coefficients and lattice constants between neighbouring shells induces stress/strain fields in the core and shells, which in turn affect their physical/mechanical properties and/or the properties of the composites containing them. In this paper, the strains in embedded and free-standing nano-onions with uniform and non-uniform compositions are studied in detail. It is found that the strains in the nano-onions can be modified by adjusting their compositions and structures. The results are useful for the band structure engineering of semiconductor nano-onions

Enhanced thermoelectric figure of merit in strained Tl-doped Bi2Se3

KAUST Repository

Saeed, Y.

2014-07-21

We explain recent experimental findings on Tl-doped Bi2Se3 by determining the electronic and transport properties by first-principles calculations and semi-classical Boltzmann theory. Though Tl-doping introduces a momentum-dependent spin-orbit splitting, the effective mass of the carriers is essentially not modified, while the band gap is reduced. Tl is found to be exceptional in this respect as other dopants modify the dispersion, which compromises thermoelectricity. Moreover, we demonstrate that only after Tl-doping strain becomes an efficient tool for enhancing the thermoelectric performance. A high figure of merit of 0.86 is obtained for strong p-doping (7 × 10^20 cm^(−3), maximal power factor) at 500 K under 2% tensile strain.

Characterization of Extracellular Polymeric Substances Produced by Pseudomonas fragi Under Air and Modified Atmosphere Packaging.

Science.gov (United States)

Wang, Guang-Yu; Ma, Fang; Wang, Hu-Hu; Xu, Xing-Lian; Zhou, Guang-Hong

2017-09-01

Extracellular polymeric substances (EPS) play an important role in bacterial biochemical properties. The characteristics of EPS from 2 strains of Pseudomonas fragi cultured in meat aerobically (control) and in modified atmosphere packaging (MAP) were studied. The amount and components of EPS, the surface properties, and the effect on biofilm formation of several spoilage organisms were evaluated. The results showed that MAP inhibited the growth of the P. fragi strains. Compared with the control, more loose and less bound EPS (containing protein and carbohydrate) were produced by P. fragi in MAP samples. MAP also caused increased cell autoaggregation and surface hydrophobicity. After the removal of the EPS, the surface property changes were strain-dependent, suggesting that membrane compositions were also changed. In addition, the EPS displayed significant antibiofilm activity on Pseudomonas fluorescens and Serratia liquefaciens. In conclusion, P. fragi strains not only modified the amount, components, and surface properties of EPS but also changed the cell membrane compositions to adapt to MAP stress. Moreover, EPS may play an important role in microbial community competitions. © 2017 Institute of Food Technologists®.

Differential effects of two strains of Rhizophagus intraradices on dry biomass and essential oil yield and composition in Calamintha nepeta

Directory of Open Access Journals (Sweden)

Roxana P Colombo

Full Text Available The aim of this work was to determine the effects of two geographically different strains of Rhizophagus intraradices (M3 and GA5 on the total biomass and essential oil (EO yield and composition of Calamintha nepeta, with or without phosphorus (P fertilization, under greenhouse conditions.The plant biomass was not significantly affected by any of the treatments, showing higher values in control plants. Strains had a differential response in their root colonization rates: M3 reduced these parameters while GA5 did not modify them. Both strains affected EO yield in absence of P fertilization: M3 promoted EO yield in C. nepeta plants and GA5 resulted in negative effects. The percentage composition of EO was not significantly modified by either strain or P fertilization. M3 strain could be a potential fungal bioinoculant for production and commercialization of C. nepeta in the aromatic plant market.

A modified Rietveld method to model highly anisotropic ceramics

International Nuclear Information System (INIS)

Tutuncu, G.; Motahari, M.; Daymond, M.R.; Ustundag, E.

2012-01-01

High energy X-ray diffraction was employed to probe the complex constitutive behavior of a polycrystalline ferroelectric material in various sample orientations. Pb(Zn,Nb)O 3 –Pb(Zr,Ti)O 3 (PZN–PZT) ceramics were subjected to a cyclic bipolar electric field while diffraction patterns were taken. Using transmission geometry and a two-dimensional detector, lattice strain and texture evolution (domain switching) were measured in multiple sample directions simultaneously. In addition, texture analysis suggests that non-180° domain switching is coupled with lattice strain evolution during uniaxial electrical loading. As a result of this material’s high strain anisotropy, the full-pattern Rietveld method was inadequate to analyze the diffraction data. Instead, a modified Rietveld method, which includes an elastic anisotropy term, yielded significant improvements in the data analysis results.

Genetic heterogeneity of L-Zagreb mumps virus vaccine strain

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Mateljak-Lukacevic Sanja

2008-07-01

Full Text Available Abstract Background The most often used mumps vaccine strains Jeryl Lynn (JL, RIT4385, Urabe-AM9, L-Zagreb and L-3 differ in immunogenicity and reactogenicity. Previous analyses showed that JL, Urabe-AM9 and L-3 are genetically heterogeneous. Results We identified the heterogeneity of L-Zagreb throughout the entire genome. Two major variants were defined: variant A being identical to the consensus sequence of viral seeds and vaccine(s and variant B which differs from variant A in three nucleotide positions. The difference between viral variants in L-Zagreb strain is insufficient for distinct viral strains to be defined. We demonstrated that proportion of variants in L-Zagreb viral population depends on cell substrate used for viral replication in vitro and in vivo. Conclusion L-Zagreb strain should be considered as a single strain composed of at least two variant viral genomes.

Genetic heterogeneity of L-Zagreb mumps virus vaccine strain

Science.gov (United States)

Kosutic-Gulija, Tanja; Forcic, Dubravko; Šantak, Maja; Ramljak, Ana; Mateljak-Lukacevic, Sanja; Mazuran, Renata

2008-01-01

Background The most often used mumps vaccine strains Jeryl Lynn (JL), RIT4385, Urabe-AM9, L-Zagreb and L-3 differ in immunogenicity and reactogenicity. Previous analyses showed that JL, Urabe-AM9 and L-3 are genetically heterogeneous. Results We identified the heterogeneity of L-Zagreb throughout the entire genome. Two major variants were defined: variant A being identical to the consensus sequence of viral seeds and vaccine(s) and variant B which differs from variant A in three nucleotide positions. The difference between viral variants in L-Zagreb strain is insufficient for distinct viral strains to be defined. We demonstrated that proportion of variants in L-Zagreb viral population depends on cell substrate used for viral replication in vitro and in vivo. Conclusion L-Zagreb strain should be considered as a single strain composed of at least two variant viral genomes. PMID:18616793

Engineering industrial Saccharomyces cerevisiae strains for xylose fermentation and comparison for switchgrass conversion

Science.gov (United States)

Saccharomyces physiology and fermentation related properties vary broadly among industrial strains. In this study, six industrial strains of varied genetic background were engineered to ferment xylose. Aerobic growth rates on xylose were 0.040 h**-1 to 0.167 h**-1. Fermentation of xylose, glucose/xy...

Advanced Background Subtraction Applied to Aeroacoustic Wind Tunnel Testing

Science.gov (United States)

Bahr, Christopher J.; Horne, William C.

2015-01-01

An advanced form of background subtraction is presented and applied to aeroacoustic wind tunnel data. A variant of this method has seen use in other fields such as climatology and medical imaging. The technique, based on an eigenvalue decomposition of the background noise cross-spectral matrix, is robust against situations where isolated background auto-spectral levels are measured to be higher than levels of combined source and background signals. It also provides an alternate estimate of the cross-spectrum, which previously might have poor definition for low signal-to-noise ratio measurements. Simulated results indicate similar performance to conventional background subtraction when the subtracted spectra are weaker than the true contaminating background levels. Superior performance is observed when the subtracted spectra are stronger than the true contaminating background levels. Experimental results show limited success in recovering signal behavior for data where conventional background subtraction fails. They also demonstrate the new subtraction technique's ability to maintain a proper coherence relationship in the modified cross-spectral matrix. Beam-forming and de-convolution results indicate the method can successfully separate sources. Results also show a reduced need for the use of diagonal removal in phased array processing, at least for the limited data sets considered.

Job strain and the risk of severe asthma exacerbations

DEFF Research Database (Denmark)

Heikkilä, K; Madsen, I E H; Nyberg, S T

2014-01-01

BACKGROUND: Many patients and healthcare professionals believe that work-related psychosocial stress, such as job strain, can make asthma worse, but this is not corroborated by empirical evidence. We investigated the associations between job strain and the incidence of severe asthma exacerbations...... in working-age European men and women. METHODS: We analysed individual-level data, collected between 1985 and 2010, from 102 175 working-age men and women in 11 prospective European studies. Job strain (a combination of high demands and low control at work) was self-reported at baseline. Incident severe...... asthma exacerbations were ascertained from national hospitalization and death registries. Associations between job strain and asthma exacerbations were modelled using Cox regression and the study-specific findings combined using random-effects meta-analyses. RESULTS: During a median follow-up of 10 years...

Polymer and bitumen-modified OPC for the immobilization of ILW

International Nuclear Information System (INIS)

Johnson, D.I.; Worrall, G.; Phillips, D.C.

1986-01-01

A detailed study has been made of the modification of ordinary Portland cement with polymeric additives, and of the properties of waste forms based on these matrix materials. The additives were styrene butadiene and bitumen emulsions, and epoxide and polyurethane resins: the simulated wastes were organic ion exchanger beads, PWR evaporator concentrate, reprocessing concentrate and Magnox metal. The effect of polymer: cement (p:c) and water:cement ratios on the properties of the hardened cement paste has been comprehensively investigated. Substantial increases in strain to failure, and modest reductions in permeability to water and leach rates for Cs 137 , are obtained at p:c > 0.2. Much larger volume fractions of organic ion exchange beads can be encapsulated in polymer modified OPC than in unmodified OPC, perhaps because of their better strain capability. The radiation stability of cemented PWR evaporator concentrate is better for a polymer-modified matrix than an unmodified OPC matrix. Two hundred litre trials have been successfully demonstrated. 20 refs, 20 tabs, 10 figs

Polymer and bitumen modified OPC for the immobilisation of ILW

International Nuclear Information System (INIS)

Johnson, D.I.; Worrall, G.; Phillips, D.C.

1986-05-01

A detailed study has been made of the modification of ordinary Portland cement with polymeric additives, and of the properties of waste forms based on these matrix materials. The additives were styrene butadiene and bitumen emulsions, and epoxide and polyurethane resins: the simulated wastes were organic ion exchanger beads, PWR evaporator concentrate, reprocessing concentrate and Magnox metal. The effect of polymer:cement (p:c) and water:cement ratios on the properties of the hardened cement paste has been comprehensively investigated. Substantial increases in strain to failure, and modest reductions in permeability to water and leach rates for 137 Cs, are obtained at p:c >= 0.2. Much larger volume fractions of organic ion exchange beads can be encapsulated in polymer modified OPC than in unmodified OPC, perhaps because of their better strain capability. The radiation stability of cemented PWR evaporator concentrate is better for a polymer modified matrix than an unmodified OPC matrix. Two hundred litre trials have been successfully demonstrated. (author)

Toxoplasma Chinese 1 Strain of WH3Δrop16I/III/gra15II Genetic Background Contributes to Abnormal Pregnant Outcomes in Murine Model

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Cong Wang

2018-06-01

upregulated in WH3Δrop16-infected mice, which gave rise to more prominent outcomes of abnormal pregnancies. Our results indicated that the WH3Δrop16 parasites with gra15II background of T. gondii type Chinese 1 strains may cause miscarriage and stillbirth due to subversion of the maternal immune tolerance and system immunity of the animals and the GRA15II effector contributes to the process of adverse pregnant consequences.

Modifying effect of caffeine on lethality and mutability of Chlamydomonas reinhardii cells following UV irradiation

International Nuclear Information System (INIS)

Podstavkova, S.; Vlcek, D.; Miadokova, E.

1983-01-01

The modifying effect of caffeine was studied using two standard and two UV-sensitive strains of Chlamydomonas reinhardii Dang. Cell survival and mutation frequency was microscopically evaluated on media without caffeine and on media with 1.5 mM of caffeine. The obtained results were indicative of the stimulating effect of caffeine upon survival in all strains. (author)

Investigation of chemical modifiers for the determination of lead in fertilizers and limestone using graphite furnace atomic absorption spectrometry with Zeeman-effect background correction and slurry sampling

Energy Technology Data Exchange (ETDEWEB)

Borges, Aline R. [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq–INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Becker, Emilene M.; Dessuy, Morgana B. [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Vale, Maria Goreti R., E-mail: mgrvale@ufrgs.br [Instituto de Química, Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves 9500, 91501-970 Porto Alegre, RS (Brazil); Instituto Nacional de Ciência e Tecnologia do CNPq–INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Welz, Bernhard [Instituto Nacional de Ciência e Tecnologia do CNPq–INCT de Energia e Ambiente, Universidade Federal da Bahia, Salvador, BA (Brazil); Departamento de Química, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC (Brazil)

2014-02-01

In this work, chemical modifiers in solution (Pd/Mg, NH{sub 4}H{sub 2}PO{sub 4} and NH{sub 4}NO{sub 3}/Pd) were compared with permanent modifiers (Ir and Ru) for the determination of lead in fertilizer and limestone samples using slurry sampling and graphite furnace atomic absorption spectrometry with Zeeman-effect background correction. The analytical line at 283.3 nm was used due to some spectral interference observed at 217.0 nm. The NH{sub 4}H{sub 2}PO{sub 4} was abandoned due to severe spectral interference even at the 283.3-nm line. For Pd/Mg and NH{sub 4}NO{sub 3}/Pd the optimum pyrolysis and atomization temperatures were 900 °C and 1900 °C, respectively. For Ru and Ir, the integrated absorbance signal was stable up to pyrolysis temperatures of 700 °C and 900 °C, respectively, and up to atomization temperature of 1700 °C. The limit of detection (LOD) was 17 ng g{sup −1} using Pd/Mg and 29 ng g{sup −1} using NH{sub 4}NO{sub 3}/Pd. Among the permanent modifiers investigated, the LOD was 22 ng g{sup −1} Pb for Ir and 10 ng g{sup −1} Pb for Ru. The accuracy of the method was evaluated using the certified reference material NIST SRM 695. Although Ru provided lower LOD, which can be attributed to a lower blank signal, only the modifiers in solution showed concordant values of Pb concentration for the NIST SRM 695 and the most of analyzed samples. Moreover, the Pd/Mg modifier provided the highest sensitivity and for this reason it is more suitable for the determination of Pb in fertilizers samples in slurry; besides this it presented a better signal-to-noise ratio than NH{sub 4}NO{sub 3}/Pd. - Highlights: • Lead has been determined in fertilizers using slurry sampling GF AAS. • The mixture of palladium and magnesium nitrates was found to be the ideal chemical modifier. • Calibration could be carried out against aqueous standard solutions. • The proposed method is much faster than the EPA method, which includes sample digestion.

The Protective Effect of Minocycline in a Paraquat-Induced Parkinson's Disease Model in Drosophila is Modified in Altered Genetic Backgrounds

Directory of Open Access Journals (Sweden)

Arati A. Inamdar

2012-01-01

Full Text Available Epidemiological studies link the herbicide paraquat to increased incidence of Parkinson's disease (PD. We previously reported that Drosophila exposed to paraquat recapitulate PD symptoms, including region-specific degeneration of dopaminergic neurons. Minocycline, a tetracycline derivative, exerts ameliorative effects in neurodegenerative disease models, including Drosophila. We investigated whether our environmental toxin-based PD model could contribute to an understanding of cellular and genetic mechanisms of minocycline action and whether we could assess potential interference with these drug effects in altered genetic backgrounds. Cofeeding of minocycline with paraquat prolonged survival, rescued mobility defects, blocked generation of reactive oxygen species, and extended dopaminergic neuron survival, as has been reported previously for a genetic model of PD in Drosophila. We then extended this study to identify potential interactions of minocycline with genes regulating dopamine homeostasis that might modify protection against paraquat and found that deficits in GTP cyclohydrolase adversely affect minocycline rescue. We further performed genetic studies to identify signaling pathways that are necessary for minocycline protection against paraquat toxicity and found that mutations in the Drosophila genes that encode c-Jun N-terminal kinase (JNK and Akt/Protein kinase B block minocycline rescue.

Rheological characterization of asphalt binders used in strain relief asphalt mixtures (SRAM)

OpenAIRE

Vasconcelos, Kamilla L.; Bariani Bernucci, Liedi Legi; Midori Takahashi, Marcia; Castelo-Branco, Verônica T. F.

2017-01-01

Abstract The use of ´interlayers´ that tolerate high tensile and shear strain that exists above cracks in deteriorated pavements is becoming an interesting solution to prevent reflective cracking. Recent advances in polymer technology have led to binders that can be used to produce interlayer mixtures with good mechanical properties. In this study, two polymer-modified asphalt binders were evaluated, both from the production of strain relief asphalt mixtures used as interlayers in the field. ...

Phenotypic evaluation and characterization of 21 industrial Saccharomyces cerevisiae yeast strains.

Science.gov (United States)

Kong, In Iok; Turner, Timothy Lee; Kim, Heejin; Kim, Soo Rin; Jin, Yong-Su

2018-02-01

Microorganisms have been studied and used extensively to produce value-added fuels and chemicals. Yeasts, specifically Saccharomyces cerevisiae, receive industrial attention because of their well-known ability to ferment glucose and produce ethanol. Thousands of natural or genetically modified S. cerevisiae have been found in industrial environments for various purposes. These industrial strains are isolated from industrial fermentation sites, and they are considered as potential host strains for superior fermentation processes. In many cases, industrial yeast strains have higher thermotolerance, increased resistances towards fermentation inhibitors and increased glucose fermentation rates under anaerobic conditions when compared with laboratory yeast strains. Despite the advantages of industrial strains, they are often not well characterized. Through screening and phenotypic characterization of commercially available industrial yeast strains, industrial fermentation processes requiring specific environmental conditions may be able to select an ideal starting yeast strain to be further engineered. Here, we have characterized and compared 21 industrial S. cerevisiae strains under multiple conditions, including their tolerance to varying pH conditions, resistance to fermentation inhibitors, sporulation efficiency and ability to ferment lignocellulosic sugars. These data may be useful for the selection of a parental strain for specific biotechnological applications of engineered yeast. © FEMS 2018. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Substructure evolution of Zircaloy-4 during creep and implications for the Modified Jogged-Screw model

Energy Technology Data Exchange (ETDEWEB)

Morrow, B.M., E-mail: morrow@lanl.gov [The Ohio State University, 2041 College Rd., 477 Watts Hall, Columbus, OH 43210 (United States); Los Alamos National Laboratory, P.O. Box 1663, MS G755, Los Alamos, NM 87545 (United States); Kozar, R.W.; Anderson, K.R. [Bettis Laboratory, Bechtel Marine Propulsion Corp., West Mifflin, PA 15122 (United States); Mills, M.J., E-mail: millsmj@mse.osu.edu [The Ohio State University, 2041 College Rd., 477 Watts Hall, Columbus, OH 43210 (United States)

2016-05-17

Several specimens of Zircaloy-4 were creep tested at a single stress-temperature condition, and interrupted at different accumulated strain levels. Substructural observations were performed using bright field scanning transmission electron microscopy (BF STEM). The dislocation substructure was characterized to ascertain how creep strain evolution impacts the Modified Jogged-Screw (MJS) model, which has previously been utilized to predict steady-state strain rates in Zircaloy-4. Special attention was paid to the evolution of individual model parameters with increasing strain. Results of model parameter measurements are reported and discussed, along with possible extensions to the MJS model.

Microbial Enhanced Oil Recovery-Laboratory Experiments with a Strain of Clostridium tyrobutyricum

DEFF Research Database (Denmark)

Jimoh, Ismaila Adetunji

the desired metabolic products needed for enhanced oil recovery. In this study, experiments have been performed with a strain of Clostridium tyrobutyricum. The experiments focused on salinity adaptation, gas production and the ability of microbes to modify rock properties. The result of the experiments showed...... that the strain of Clostridium tyrobutyricum adapted to 10, 30, 50, and 90 g/l before the start of the experiments produce more gas with an increase factor of between 0.39-6.9 for the same salinity condition than the pure culture. The adaptation process also led to the production of a strain 90F which can grow...

Use of colony-based bacterial strain typing for tracking the fate of Lactobacillus strains during human consumption

Directory of Open Access Journals (Sweden)

Drevinek Pavel

2009-12-01

Full Text Available Abstract Background The Lactic Acid Bacteria (LAB are important components of the healthy gut flora and have been used extensively as probiotics. Understanding the cultivable diversity of LAB before and after probiotic administration, and being able to track the fate of administered probiotic isolates during feeding are important parameters to consider in the design of clinical trials to assess probiotic efficacy. Several methods may be used to identify bacteria at the strain level, however, PCR-based methods such as Random Amplified Polymorphic DNA (RAPD are particularly suited to rapid analysis. We examined the cultivable diversity of LAB in the human gut before and after feeding with two Lactobacillus strains, and also tracked the fate of these two administered strains using a RAPD technique. Results A RAPD typing scheme was developed to genetically type LAB isolates from a wide range of species, and optimised for direct application to bacterial colony growth. A high-throughput strategy for fingerprinting the cultivable diversity of human faeces was developed and used to determine: (i the initial cultivable LAB strain diversity in the human gut, and (ii the fate of two Lactobacillus strains (Lactobacillus salivarius NCIMB 30211 and Lactobacillus acidophilus NCIMB 30156 contained within a capsule that was administered in a small-scale human feeding study. The L. salivarius strain was not cultivated from the faeces of any of the 12 volunteers prior to capsule administration, but appeared post-feeding in four. Strains matching the L. acidophilus NCIMB 30156 feeding strain were found in the faeces of three volunteers prior to consumption; after taking the Lactobacillus capsule, 10 of the 12 volunteers were culture positive for this strain. The appearance of both Lactobacillus strains during capsule consumption was statistically significant (p Conclusion We have shown that genetic strain typing of the cultivable human gut microbiota can be

Effect of strain rate and stress triaxiality on tensile behavior of Titanium alloy Ti-10-2-3 at elevated temperatures

Energy Technology Data Exchange (ETDEWEB)

Bobbili, Ravindranadh, E-mail: ravindranadh@dmrl.drdo.in; Madhu, Vemuri

2016-06-14

In this study, Split hopkinson tension bar (SHTB) has been employed to investigate the dynamic tensile flow behavior of Ti-10-2-3 alloy at high strain rates and elevated temperatures. The combined effect of stress triaxiality, strain rate and temperature and on the tensile behavior of the alloy was evaluated. Johnson-Cook (J-C) constitutive and fracture models were developed based on high strain rate tensile data. A modified Johnson–Cook model was established and proved to have high accuracy. A comparative assessment has been done to confirm the accuracy of modified J–C model based on finite element method (FEM). The improved model provides better description on the influence of equivalent plastic strain rate and temperature on the plastic flow. The simulation results proved to be in good agreement with the experimental data. The fracture surfaces of specimens tested under various strain rates and temperatures were studied under scanning electron microscopy (SEM).

A glycoprotein with anti-inflammatory properties secreted by an Aspergillus nidulans modified strain

Directory of Open Access Journals (Sweden)

J. C. F. Queiroz

2007-01-01

Full Text Available Total RNA from lipopolysaccharide (LPS-stimulated rat macrophages used to treat protoplasts from an Aspergillus nidulans strain originated the RT2 regenerated strain, whose culture supernatant showed anti-inflammatory activity in Wistar rats. The protein fraction presenting such anti-inflammatory activity was purified and biochemically identified. The screening of the fraction responsible for such anti-inflammatory property was performed by evaluating the inhibition of carrageenan-induced paw edema in male Swiss mice. Biochemical analyses of the anti-inflammatory protein used chromatography, carbohydrates quantification of the protein sample, amino acids content analysis and sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE. Total sugar quantification revealed 32% glycosylation of the protein fraction. Amino acid analysis of such fraction showed a peculiar pattern presenting 29% valine. SDS-PAGE revealed that the protein sample is pure and its molecular weight is about 40kDa. Intravenous injection of the isolated substance into mice significantly inhibited carrageenan-induced paw edema. The isolated glycoprotein decreased carrageenan-induced paw edema in a prostaglandin-dependent phase, suggesting an inhibitory effect of the isolated glycoprotein on prostaglandin synthesis.

Lactobacillus delbrueckii subsp. lactis (strain CIDCA 133) stimulates murine macrophages infected with Citrobacter rodentium.

Science.gov (United States)

Hugo, Ayelén A; Rolny, Ivanna S; Romanin, David; Pérez, Pablo F

2017-03-01

Citrobacter rodentium is a specific murine enteropathogen which causes diarrheal disease characterized by colonic hyperplasia and intestinal inflammation. Recruitment of neutrophils and macrophages constitute a key step to control the infection. Since modulation of the activity of professional phagocytic cells could contribute to improve host´s defences against C. rodentium, we investigated the effect of Lactobacillus delbrueckii subsp. lactis (strain CIDCA 133) on the interaction between murine macrophages (RAW 264.7) and C. rodentium. Phagocytosis, surface molecules and inducible nitric oxide synthase (iNOs) expression were determined by flow cytometry. Reactive oxygen species (ROS) were assessed by fluorescence microscopy. The presence of lactobacilli increased phagocytosis of C. rodentium whereas C. rodentium had no effect on lactobacilli internalization. Survival of internalized C. rodentium diminished when strain CIDCA 133 was present. CD-86, MHCII, iNOs expression and nitrite production were increased when C. rodentium and lactobacilli were present even though strain CIDCA 133 alone had no effect. Strain CIDCA 133 led to a strong induction of ROS activity which was not modified by C. rodentium. Lactobacillus delbrueckii subsp. lactis (strain CIDCA 133) is able to increase the activation of murine macrophages infected with C. rodentium. The sole presence of lactobacilli is enough to modify some stimulation markers (e.g. ROS induction) whereas other markers require the presence of both bacteria; thus, indicating a synergistic effect.

International Clostridium difficile animal strain collection and large diversity of animal associated strains

DEFF Research Database (Denmark)

Janezic, Sandra; Zidaric, Valerija; Pardon, Bart

2014-01-01

Background: Clostridium difficile is an important cause of intestinal infections in some animal species and animals might be a reservoir for community associated human infections. Here we describe a collection of animal associated C. difficile strains from 12 countries based on inclusion criteria...... of one strain (PCR ribotype) per animal species per laboratory. Results: Altogether 112 isolates were collected and distributed into 38 PCR ribotypes with agarose based approach and 50 PCR ribotypes with sequencer based approach. Four PCR ribotypes were most prevalent in terms of number of isolates...... as well as in terms of number of different host species: 078 (14.3% of isolates; 4 hosts), 014/020 (11.6%; 8 hosts); 002 (5.4%; 4 hosts) and 012 (5.4%; 5 hosts). Two animal hosts were best represented; cattle with 31 isolates (20 PCR ribotypes; 7 countries) and pigs with 31 isolates (16 PCR ribotypes; 10...

Left ventricular strain and strain rate by 2D speckle tracking in chronic thromboembolic pulmonary hypertension before and after pulmonary thromboendarterectomy

Directory of Open Access Journals (Sweden)

Waltman Thomas J

2010-09-01

Full Text Available Abstract Background Echocardiographic evaluation of left ventricular (LV strain and strain rate (SR by 2D speckle tracking may be useful tools to assess chronic thromboembolic pulmonary hypertension (CTEPH severity as well as response to successful pulmonary thromboendarterectomy (PTE. Methods We evaluated 30 patients with CTEPH before and after PTE using 2D speckle tracking measurements of LV radial and circumferential strain and SR in the short axis, and correlated the data with right heart catheterization (RHC. Results PTE resulted in a decrease in mean PA pressure (44 ± 15 to 29 ± 9 mmHg, decrease in PVR (950 ± 550 to 31 ± 160 [dyne-sec]/cm5, and an increase in cardiac output (3.9 ± 1.0 to 5.0 ± 1.0 L/min, p change in circumferential strain and change in posterior wall radial strain correlated moderately well with changes in PVR, mean PA pressure and cardiac output (r = 0.69, 0.76, and 0.51 for circumferential strain [p Conclusions LV circumferential and posterior wall radial strain change after relief of pulmonary arterial obstruction in patients with CTEPH, and these improvements occur rapidly. These changes in LV strain may reflect effects from improved LV diastolic filling, and may be useful non-invasive markers of successful PTE.

Development of modified piping evaluation diagram for LBB application to Korean next generation reactor

International Nuclear Information System (INIS)

Huh, Nam Su; Kim, Young Jin; Pyo, Chang ryul; Yu, Young Jun; Yang, Jun Seog

1999-01-01

Recently, the Piping Evaluation Diagram (PED) is accepted in nuclear industry for simple application of Leak-Before-Break (LBB) concept to piping system. By utilizing the PED, the LBB concept is applied before the piping layout is finalized. However, the developed PED may have to be modified to account for the difference between the material properties of the PED development stage and those of the assembly stage. The objective of this paper is to develop the modified PED which can account for the variation of material properties. For this purpose, a parametric study was performed to investigate the effect of stress-strain curve on the detectable crack length and the effect of fracture resistance curve on the LBB allowable load. Finite element analyses were also performed to investigate the effect of stress-strain curve on the LBB allowable load. Finally a modified PED is developed as a function of crack length (DLC and 2xDLC) and the allowable Safe shutdown Earthquake (SSE) load. By adopting the modified PED, the variation of material properties can be considered in the LBB analysis and the computer runs required for the LBB analysis can be considerably reduced

SHuffle, a novel Escherichia coli protein expression strain capable of correctly folding disulfide bonded proteins in its cytoplasm

Directory of Open Access Journals (Sweden)

Lobstein Julie

2012-05-01

Full Text Available Abstract Background Production of correctly disulfide bonded proteins to high yields remains a challenge. Recombinant protein expression in Escherichia coli is the popular choice, especially within the research community. While there is an ever growing demand for new expression strains, few strains are dedicated to post-translational modifications, such as disulfide bond formation. Thus, new protein expression strains must be engineered and the parameters involved in producing disulfide bonded proteins must be understood. Results We have engineered a new E. coli protein expression strain named SHuffle, dedicated to producing correctly disulfide bonded active proteins to high yields within its cytoplasm. This strain is based on the trxB gor suppressor strain SMG96 where its cytoplasmic reductive pathways have been diminished, allowing for the formation of disulfide bonds in the cytoplasm. We have further engineered a major improvement by integrating into its chromosome a signal sequenceless disulfide bond isomerase, DsbC. We probed the redox state of DsbC in the oxidizing cytoplasm and evaluated its role in assisting the formation of correctly folded multi-disulfide bonded proteins. We optimized protein expression conditions, varying temperature, induction conditions, strain background and the co-expression of various helper proteins. We found that temperature has the biggest impact on improving yields and that the E. coli B strain background of this strain was superior to the K12 version. We also discovered that auto-expression of substrate target proteins using this strain resulted in higher yields of active pure protein. Finally, we found that co-expression of mutant thioredoxins and PDI homologs improved yields of various substrate proteins. Conclusions This work is the first extensive characterization of the trxB gor suppressor strain. The results presented should help researchers design the appropriate protein expression conditions using

Background Noise Reduction Using Adaptive Noise Cancellation Determined by the Cross-Correlation

Science.gov (United States)

Spalt, Taylor B.; Brooks, Thomas F.; Fuller, Christopher R.

2012-01-01

Background noise due to flow in wind tunnels contaminates desired data by decreasing the Signal-to-Noise Ratio. The use of Adaptive Noise Cancellation to remove background noise at measurement microphones is compromised when the reference sensor measures both background and desired noise. The technique proposed modifies the classical processing configuration based on the cross-correlation between the reference and primary microphone. Background noise attenuation is achieved using a cross-correlation sample width that encompasses only the background noise and a matched delay for the adaptive processing. A present limitation of the method is that a minimum time delay between the background noise and desired signal must exist in order for the correlated parts of the desired signal to be separated from the background noise in the crosscorrelation. A simulation yields primary signal recovery which can be predicted from the coherence of the background noise between the channels. Results are compared with two existing methods.

Study of the dislocation contribution to the internal friction background of gold

Science.gov (United States)

Baur, J.; Benoit, W.

1987-04-01

The dislocation contribution to the internal friction (IF) background is studied in annealed gold samples containing various dilute concentrations of platinum impurities. The measurements are performed in the kHz frequency range in order to determine the loss mechanism responsible for the high IF background observed at these low frequencies. To this end, the IF background was systematically measured as a function of frequency, vibration amplitude, temperature, and impurity concentration. The experimental results show that the high dislocation contribution observed in annealed samples is strain-amplitude independent for amplitudes in the range 10-7 to 2×10-6, but rapidly decreases for amplitudes smaller than 10-7. In particular, the dislocation contribution tends to zero when the strain amplitude tends to zero. Furthermore, this contribution is frequency independent. These observations demonstrate that the dislocation contribution cannot be explained by relaxations. In particular, this contribution cannot be attributed to a viscous damping of the dislocation motion. On the contrary, the experiments show that the IF background due to dislocations must be explained by hysteretic and athermal motions of dislocations interacting with point defects. However, these hysteretic motions are not due to breakaway of dislocations from pinning points distributed along their length. The experimental results can be explained by the presence of point defects close to the dislocations, but not on them. The mechanical energy loss is attributed to hysteretic motions of dislocations between potential minima created by point defects.

Energy absorption at high strain rate of glass fiber reinforced mortars

Directory of Open Access Journals (Sweden)

Fenu Luigi

2015-01-01

Full Text Available In this paper, the dynamic behaviour of cement mortars reinforced with glass fibers was studied. The influence of the addition of glass fibers on energy absorption and tensile strength at high strain-rate was investigated. Static tests in compression, in tension and in bending were first performed. Dynamic tests by means of a Modified Hopkinson Bar were then carried out in order to investigate how glass fibers affected energy absorption and tensile strength at high strain-rate of the fiber reinforced mortar. The Dynamic Increase Factor (DIF was finally evaluated.

Strain-activated edge reconstruction of graphene nanoribbons

KAUST Repository

Cheng, Yingchun

2012-02-17

The edge structure and width of graphene nanoribbons (GNRs) are crucial factors for the electronic properties. A combination of experiment and first-principles calculations allows us to determine the mechanism of the hexagon-hexagon to pentagon-heptagon transformation. GNRs thinner than 2 nm have been fabricated by bombardment of graphene with high-energetic Au clusters. The edges of the GNRs are modified in situ by electron irradiation. Tensile strain along the edge decreases the transformation energy barrier. Antiferromagnetism and a direct band gap are found for a zigzag GNR, while a fully reconstructed GNR shows an indirect band gap. A GNR reconstructed on only one edge exhibits ferromagnetism. We propose that strain is an effective method to tune the edge and, therefore, the electronic structure of thin GNRs for graphene-based electronics.

Strain-activated edge reconstruction of graphene nanoribbons

KAUST Repository

Cheng, Yingchun; Han, Yu; Schwingenschlö gl, Udo; Wang, H. T.; Zhang, Xixiang; Zhu, Y. H.; Zhu, Zhiyong

2012-01-01

The edge structure and width of graphene nanoribbons (GNRs) are crucial factors for the electronic properties. A combination of experiment and first-principles calculations allows us to determine the mechanism of the hexagon-hexagon to pentagon-heptagon transformation. GNRs thinner than 2 nm have been fabricated by bombardment of graphene with high-energetic Au clusters. The edges of the GNRs are modified in situ by electron irradiation. Tensile strain along the edge decreases the transformation energy barrier. Antiferromagnetism and a direct band gap are found for a zigzag GNR, while a fully reconstructed GNR shows an indirect band gap. A GNR reconstructed on only one edge exhibits ferromagnetism. We propose that strain is an effective method to tune the edge and, therefore, the electronic structure of thin GNRs for graphene-based electronics.

Numerical simulation of elasto-plastic electro-osmosis consolidation at large strain

NARCIS (Netherlands)

Yuan, J.; Hicks, M.A.

2015-01-01

n this paper, a numerical solution for the electro-osmosis consolidation of clay in multi-dimensional domains at large strains is presented, with the coupling of the soil mechanical behaviour, pore water transport and electrical fields being considered. In particular, the Modified Cam Clay model is

Strain-specific induction of experimental autoimmune prostatitis (EAP) in mice.

Science.gov (United States)

Jackson, Christopher M; Flies, Dallas B; Mosse, Claudio A; Parwani, Anil; Hipkiss, Edward L; Drake, Charles G

2013-05-01

Prostatitis, a clinical syndrome characterized by pelvic pain and inflammation, is common in adult males. Although several induced and spontaneous murine models of prostatitis have been explored, the role of genetic background on induction has not been well-defined. Using a standard methodology for the induction of experimental autoimmune prostatitis (EAP), we investigated both acute and chronic inflammation on several murine genetic backgrounds. In our colony, nonobese diabetic (NOD) mice evinced spontaneous prostatitis that was not augmented by immunization with rat prostate extract (RPE). In contrast, the standard laboratory strain Balb/c developed chronic inflammation in response to RPE immunization. Development of EAP in other strains was variable. These data suggest that Balb/c mice injected with RPE may provide a useful model for chronic prostatic inflammation. Copyright © 2012 Wiley Periodicals, Inc.

Fiber Optic Rosette Strain Gauge Development and Application on a Large-Scale Composite Structure

Science.gov (United States)

Moore, Jason P.; Przekop, Adam; Juarez, Peter D.; Roth, Mark C.

2015-01-01

A detailed description of the construction, application, and measurement of 196 FO rosette strain gauges that measured multi-axis strain across the outside upper surface of the forward bulkhead component of a multibay composite fuselage test article is presented. A background of the FO strain gauge and the FO measurement system as utilized in this application is given and results for the higher load cases of the testing sequence are shown.

THE STUDY OF RESISTENCE OF STAPHYLOCOCCUS AUREUS STRAINS TO ANTIMICROBIALS

OpenAIRE

Nazarchuk GG; Paliy DV; Nazarchuk OA

2012-01-01

In the research work the results of the study of resistance forming to antibiotics, antiseptics and decametoxine composition with modified polysaccharides in S.aureus strains are presented. The development of resistance to penicillins, cephalosporins, glycopeptides, macrolides is shown. Slow forming of resistance to decasan and decametoxine composition with carboxymethylamylum, oxyethylcellulose was determined.

Antiplasmodial activity of new 4-aminoquinoline derivatives against chloroquine resistant strain.

Science.gov (United States)

Sinha, Manish; Dola, Vasanth R; Agarwal, Pooja; Srivastava, Kumkum; Haq, Wahajul; Puri, Sunil K; Katti, Seturam B

2014-07-15

Emergence and spread of multidrug resistant strains of Plasmodium falciparum has severely limited the antimalarial chemotherapeutic options. In order to overcome the obstacle, a set of new side-chain modified 4-aminoquinolines were synthesized and screened against chloroquine-sensitive (3D7) and chloroquine-resistant (K1) strains of P. falciparum. The key feature of the designed molecules is the use of methylpiperazine linked α, β(3)- and γ-amino acids to generate novel side chain modified 4-aminoquinoline analogues. Among the evaluated compounds, 20c and 30 were found more potent than CQ against K1 and displayed a four-fold and a three-fold higher activity respectively, with a good selectivity index (SI=5846 and 11,350). All synthesized compounds had resistance index between 1.06 and >14.13 as against 47.2 for chloroquine. Biophysical studies suggested that this series of compounds act on heme polymerization target. Copyright © 2014 Elsevier Ltd. All rights reserved.

Occupation-specific screening for future sickness absence: Criterion validity of the trucker strain monitor (TSM)

NARCIS (Netherlands)

Croon, E.M.de; Blonk, R.W.; Sluiter, J.K.; Frings-Dresen, M.H.

2005-01-01

Background: Monitoring psychological job strain may help occupational physicians to take preventive action at the appropriate time. For this purpose, the 10-item trucker strain monitor (TSM) assessing work-related fatigue and sleeping problems in truck drivers was developed. Objectives: This study

A modified Gurson-type plasticity model at finite strains: formulation, numerical analysis and phase-field coupling

Science.gov (United States)

Aldakheel, Fadi; Wriggers, Peter; Miehe, Christian

2017-12-01

The modeling of failure in ductile materials must account for complex phenomena at the micro-scale, such as nucleation, growth and coalescence of micro-voids, as well as the final rupture at the macro-scale, as rooted in the work of Gurson (J Eng Mater Technol 99:2-15, 1977). Within a top-down viewpoint, this can be achieved by the combination of a micro-structure-informed elastic-plastic model for a porous medium with a concept for the modeling of macroscopic crack discontinuities. The modeling of macroscopic cracks can be achieved in a convenient way by recently developed continuum phase field approaches to fracture, which are based on the regularization of sharp crack discontinuities, see Miehe et al. (Comput Methods Appl Mech Eng 294:486-522, 2015). This avoids the use of complex discretization methods for crack discontinuities, and can account for complex crack patterns. In this work, we develop a new theoretical and computational framework for the phase field modeling of ductile fracture in conventional elastic-plastic solids under finite strain deformation. It combines modified structures of Gurson-Tvergaard-Needelman GTN-type plasticity model outlined in Tvergaard and Needleman (Acta Metall 32:157-169, 1984) and Nahshon and Hutchinson (Eur J Mech A Solids 27:1-17, 2008) with a new evolution equation for the crack phase field. An important aspect of this work is the development of a robust Explicit-Implicit numerical integration scheme for the highly nonlinear rate equations of the enhanced GTN model, resulting with a low computational cost strategy. The performance of the formulation is underlined by means of some representative examples, including the development of the experimentally observed cup-cone failure mechanism.

[Comparison of the quick Gram stain method to the B&M modified and favor methods].

Science.gov (United States)

Osawa, Kayo; Kataoka, Nobumasa; Maruo, Toshio

2011-01-01

The Gram stain is an established method for bacterial identification, but the time needed to carry out this stain is 2-3 min. We attempted to shorten this time and stained a total of 70 clinical specimens isolated from using the Bartholomew & Mittwer (B&M) modified or Favor methods with a 3 s duration for washing and staining steps. Results were plotted and analyzed using a Hue Saturation Intensity (HSI) model. The range based on a plot of the two methods with the HSI model was presented as a reference interval. Our results indicated that 100% (35/35) of strains were Gram positive and 97.1% (34/35) were Gram negative for the quick B&M modified method. In the quick Favor method, 80.0% (28/35) were Gram positive and 68.6% (24/35) of strains were Gram negative. We propose that the quick B&M modified method is equivalent to the standard Gram staining method and is superior to the quick Favor method.

Microbiology of the surface water samples in the high background radiation areas of Ramsar, Iran

International Nuclear Information System (INIS)

Motamedifar, Mohammad; Zamani, Khosrow; Sedigh, Hadi; Mortazavi, Seyed Mohammad Javad; Taeb, Shahram; Haghani, M.; Mortazavi, Seyed Ali Reza; Soofi, Amir

2014-01-01

Residents of high background radiation areas of Ramsar have lived in these areas for many generations and received radiation doses much higher than the dose limit recommended by ICRP for radiation workers. The radioactivity of the high background radiation areas of Ramsar is reported to be due to 226 Ra and its decay products, which have been brought to the surface by the waters of hot springs. Over the past years the department has focused on different aspects of the health effects of the elevated levels of natural radiation in Ramsar. This study was aimed to perform a preliminary investigation on the bioeffects of exposure to elevated levels of natural radiation on the microbiology of surface water samples. Water samples were collected from surface water streams in Talesh Mahalleh district, Ramsar as well as a nearby area with normal levels of background radiation. Only two strains of bacteria, that is, Providencia stuartii and Shimwellia blattae, could be isolated from the water samples collected from high background radiation areas, while seven strains (Escherichia coli, Enterobacter asburiae, Klebsiella pneumoniae, Shigella dysenteriae, Buttiauxella agerstis, Tatumella punctuata and Raoultella ornithinolytica) were isolated from the water samples collected from normal background radiation areas. All the bacteria isolated from water samples of high and normal background radiation areas were sensitive to ultraviolet radiation, heat, betadine, alcohol, and deconex. Although other investigators have reported that bacteria isolated from hot springs show radioresistance, the results reported here do not reveal any adaptive response. (author)

Magnetic attachment for implant overdentures: influence of contact relationship with the denture base on stability and bending strain.

Science.gov (United States)

Yang, Tsung-Chieh; Maeda, Yoshinobu; Gonda, Tomoya; Wada, Masahiro

2013-01-01

This study evaluated how the contact height between the magnetic attachment and denture base influences stability and bending strain. An implant modified with strain gauges and a magnetic attachment mounted in an acrylic resin block were used to characterize systems with varying degrees or heights of contact with the abutment. Bending strain under lateral loading increased significantly as the contact height decreased. In the no contact and resilient contact groups, magnetic assemblies separated at reduced bending strain in all loading conditions. The contact height of the magnetic attachment influenced the stability and the amount of bending strain on the implant.

The role of genetic background in susceptibility to chemical warfare nerve agents across rodent and non-human primate models.

Science.gov (United States)

Matson, Liana M; McCarren, Hilary S; Cadieux, C Linn; Cerasoli, Douglas M; McDonough, John H

2018-01-15

Genetics likely play a role in various responses to nerve agent exposure, as genetic background plays an important role in behavioral, neurological, and physiological responses to environmental stimuli. Mouse strains or selected lines can be used to identify susceptibility based on background genetic features to nerve agent exposure. Additional genetic techniques can then be used to identify mechanisms underlying resistance and sensitivity, with the ultimate goal of developing more effective and targeted therapies. Here, we discuss the available literature on strain and selected line differences in cholinesterase activity levels and response to nerve agent-induced toxicity and seizures. We also discuss the available cholinesterase and toxicity literature across different non-human primate species. The available data suggest that robust genetic differences exist in cholinesterase activity, nerve agent-induced toxicity, and chemical-induced seizures. Available cholinesterase data suggest that acetylcholinesterase activity differs across strains, but are limited by the paucity of carboxylesterase data in strains and selected lines. Toxicity and seizures, two outcomes of nerve agent exposure, have not been fully evaluated for genetic differences, and thus further studies are required to understand baseline strain and selected line differences. Published by Elsevier B.V.

Simulation and Experimental Investigations on the Strain Measurement of the Uniform Strength Beam Using a FBG sensor

International Nuclear Information System (INIS)

Tu Yumeng; Gong Huaping; Chen Jixuan; Jin Yongxing

2011-01-01

The model of force analysis on a uniform strength beam is built by the general finite element program (ANSYS software). The flexivity profile produced by uniform strength beam with different forces is simulated by ANSYS software. In experiment, a fiber Bragg grating sensor is fixed on the uniform strength beam with modified acrylate. The flexivity and strain are varied by changing the load on the end of the beam. The strain of the uniform strength beam is measured with FBG when applied force is varied from 2.45N to14.7N with a step of 2.45N. Both the simulated and experimental results show that, the strain induced by the uniform strength beam is linear with the load force. The sensitivity is 18.32με/N for experimental measurement, and 19.72με/N for simulation. The experimental results are consistent with the simulation results, with the maximum measurement error of strain being 7.4%. It indicates that, the FBG sensor fixed with modified acrylate is proved to be effectively and reliably in the applications of civil engineering.

THE STUDY OF RESISTENCE OF STAPHYLOCOCCUS AUREUS STRAINS TO ANTIMICROBIALS

Directory of Open Access Journals (Sweden)

Nazarchuk GG

2012-12-01

Full Text Available In the research work the results of the study of resistance forming to antibiotics, antiseptics and decametoxine composition with modified polysaccharides in S.aureus strains are presented. The development of resistance to penicillins, cephalosporins, glycopeptides, macrolides is shown. Slow forming of resistance to decasan and decametoxine composition with carboxymethylamylum, oxyethylcellulose was determined.

Antigenic characterization of a formalin-inactivated poliovirus vaccine derived from live-attenuated Sabin strains.

Science.gov (United States)

Tano, Yoshio; Shimizu, Hiroyuki; Martin, Javier; Nishimura, Yorihiro; Simizu, Bunsiti; Miyamura, Tatsuo

2007-10-10

A candidate inactivated poliovirus vaccine derived from live-attenuated Sabin strains (sIPV), which are used in the oral poliovirus vaccine (OPV), was prepared in a large-production scale. The modification of viral antigenic epitopes during the formalin inactivation process was investigated by capture ELISA assays using type-specific and antigenic site-specific monoclonal antibodies (MoAbs). The major antigenic site 1 was modified during the formalin inactivation of Sabin 1. Antigenic sites 1-3 were slightly modified during the formalin inactivation of Sabin 2 strain. Sites 1 and 3 were altered on inactivated Sabin 3 virus. These alterations were different to those shown by wild-type Saukett strain, used in conventional IPV (cIPV). It has been previously reported that type 1 sIPV showed higher immunogenicity to type 1 cIPV whereas types 2 and 3 sIPV induced lower level of immunogenicity than their cIPV counterparts. Our results suggest that the differences in epitope structure after formalin inactivation may account, at least in part, for the observed differences in immunogenicity between Sabin and wild-type inactivated poliovaccines.

TCDD-induced transcriptional profiles in different mouse strains that have an identical AhR genotype

Energy Technology Data Exchange (ETDEWEB)

Wu, Qing; Suzuki, Junko S.; Tohyama, Chiharu; Ohsako, Seiichiroh [Environmental Health Sciences Division, National Institute for Environmental Studies, Onogawa, Tsukuba (Japan); Takei, Teiji [Environmental Health and Safety Division, Ministry of the Environment, Kasumigaseki, Tokyo (Japan); Lin, Tinmin; Peterson, R.E. [Wisconsin Univ., Wisconsin, MA (United States). School of Pharmacy and Molecular and Environmental Toxicology Center

2004-09-15

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is an environmental contaminant that is known to cause hepatotoxicity, teratogenicity and carcinogenicity. A characteristic feature in the toxicity of TCDD is exceptionally large differences in susceptibility among animal species or even strains belonging to the same species. These strain differences in susceptibility to TCDD have now been elucidated to be due to the difference in ligand binding affinity or transcriptional activity of the aryl hydrocarbon receptor (AhR). Actually the C57BL/6 type AhR (AhR{sup b}) showed 6-fold higher ligand binding affinity than the DBA/2 type AhR (AhR{sup d}). The H/W rat AhR has a C-terminal truncation of the transactivating domain compared to the L-E rat AhR. On the other hand, there is considerable species variability in response sensitivity to TCDD that cannot be ascribed simply to polymorphisms of the AhR gene. A non-AhR gene susceptibility loci for hepatic porphyria has been observed in mice treated with iron compounds prior to TCDD injection by using a quantitative trait locus analysis of an F2 intercross between susceptible C57BL/6 and resistant DBA/2 stains. In the rat, a gene B with Han/Wistar type AhR is likely to be involved in resistance to TCDD lethality. These observations suggest that other modulating genes, so-called ''modifier genes'', have profound effects on the AhR-mediated gene expression phenotype. Based on the nucleotide sequence of the AhR coding region, the BALB/c, CBA/J, and C3H/He mouse strains are clustered together on a single branch. In the present study, we try to confirm the existence of modifiers by using microarray analysis to examine hepatic gene expression after TCDD exposure in BALB/c, CBA/J, and C3H/He mice. To recognize the existence of a modifier besides the AhR, it is a prerequisite experimental condition that the analyzed strains have an identical AhR genotype. Therefore, we selected BALB/c, CBA/J, and C3H/He mice as the model

Genome Analysis of the Biotechnologically Relevant Acidophilic Iron Oxidising Strain JA12 Indicates Phylogenetic and Metabolic Diversity within the Novel Genus “Ferrovum”

Science.gov (United States)

Ullrich, Sophie R.; Poehlein, Anja; Tischler, Judith S.; González, Carolina; Ossandon, Francisco J.; Daniel, Rolf; Holmes, David S.; Schlömann, Michael; Mühling, Martin

2016-01-01

Background Members of the genus “Ferrovum” are ubiquitously distributed in acid mine drainage (AMD) waters which are characterised by their high metal and sulfate loads. So far isolation and microbiological characterisation have only been successful for the designated type strain “Ferrovum myxofaciens” P3G. Thus, knowledge about physiological characteristics and the phylogeny of the genus “Ferrovum” is extremely scarce. Objective In order to access the wider genetic pool of the genus “Ferrovum” we sequenced the genome of a “Ferrovum”-containing mixed culture and successfully assembled the almost complete genome sequence of the novel “Ferrovum” strain JA12. Phylogeny and Lifestyle The genome-based phylogenetic analysis indicates that strain JA12 and the type strain represent two distinct “Ferrovum” species. “Ferrovum” strain JA12 is characterised by an unusually small genome in comparison to the type strain and other iron oxidising bacteria. The prediction of nutrient assimilation pathways suggests that “Ferrovum” strain JA12 maintains a chemolithoautotrophic lifestyle utilising carbon dioxide and bicarbonate, ammonium and urea, sulfate, phosphate and ferrous iron as carbon, nitrogen, sulfur, phosphorous and energy sources, respectively. Unique Metabolic Features The potential utilisation of urea by “Ferrovum” strain JA12 is moreover remarkable since it may furthermore represent a strategy among extreme acidophiles to cope with the acidic environment. Unlike other acidophilic chemolithoautotrophs “Ferrovum” strain JA12 exhibits a complete tricarboxylic acid cycle, a metabolic feature shared with the closer related neutrophilic iron oxidisers among the Betaproteobacteria including Sideroxydans lithotrophicus and Thiobacillus denitrificans. Furthermore, the absence of characteristic redox proteins involved in iron oxidation in the well-studied acidophiles Acidithiobacillus ferrooxidans (rusticyanin) and Acidithiobacillus

Genome sequencing and analysis of BCG vaccine strains.

Directory of Open Access Journals (Sweden)

Wen Zhang

Full Text Available BACKGROUND: Although the Bacillus Calmette-Guérin (BCG vaccine against tuberculosis (TB has been available for more than 75 years, one third of the world's population is still infected with Mycobacterium tuberculosis and approximately 2 million people die of TB every year. To reduce this immense TB burden, a clearer understanding of the functional genes underlying the action of BCG and the development of new vaccines are urgently needed. METHODS AND FINDINGS: Comparative genomic analysis of 19 M. tuberculosis complex strains showed that BCG strains underwent repeated human manipulation, had higher region of deletion rates than those of natural M. tuberculosis strains, and lost several essential components such as T-cell epitopes. A total of 188 BCG strain T-cell epitopes were lost to various degrees. The non-virulent BCG Tokyo strain, which has the largest number of T-cell epitopes (359, lost 124. Here we propose that BCG strain protection variability results from different epitopes. This study is the first to present BCG as a model organism for genetics research. BCG strains have a very well-documented history and now detailed genome information. Genome comparison revealed the selection process of BCG strains under human manipulation (1908-1966. CONCLUSIONS: Our results revealed the cause of BCG vaccine strain protection variability at the genome level and supported the hypothesis that the restoration of lost BCG Tokyo epitopes is a useful future vaccine development strategy. Furthermore, these detailed BCG vaccine genome investigation results will be useful in microbial genetics, microbial engineering and other research fields.

Relation Between Motility, Accelerated Aging and Gene Expression in Selected Drosophila Strains under Hypergravity Conditions

Science.gov (United States)

Serrano, Paloma; van Loon, Jack J. W. A.; Medina, F. Javier; Herranz, Raúl

2013-02-01

Motility and aging in Drosophila have proven to be highly modified under altered gravity conditions (both in space and ground simulation facilities). In order to find out how closely connected they are, five strains with altered geotactic response or survival rates were selected and exposed to an altered gravity environment of 2 g. By analysing the different motile and behavioural patterns and the median survival rates, we show that altered gravity leads to changes in motility, which will have a negative impact on the flies' survival. Previous results show a differential gene expression between sessile samples and adults and confirm that environmentally-conditioned behavioural patterns constrain flies' gene expression and life span. Therefore, hypergravity is considered an environmental stress factor and strains that do not respond to this new environment experience an increment in motility, which is the major cause for the observed increased mortality also under microgravity conditions. The neutral-geotaxis selected strain (strain M) showed the most severe phenotype, unable to respond to variations in the gravitational field. Alternatively, the opposite phenotype was observed in positive-geotaxis and long-life selected flies (strains B and L, respectively), suggesting that these populations are less sensitive to alterations in the gravitational load. We conclude that the behavioural response has a greater contribution to aging than the modified energy consumption in altered gravity environments.

Modified dispersion relations, inflation, and scale invariance

Science.gov (United States)

Bianco, Stefano; Friedhoff, Victor Nicolai; Wilson-Ewing, Edward

2018-02-01

For a certain type of modified dispersion relations, the vacuum quantum state for very short wavelength cosmological perturbations is scale-invariant and it has been suggested that this may be the source of the scale-invariance observed in the temperature anisotropies in the cosmic microwave background. We point out that for this scenario to be possible, it is necessary to redshift these short wavelength modes to cosmological scales in such a way that the scale-invariance is not lost. This requires nontrivial background dynamics before the onset of standard radiation-dominated cosmology; we demonstrate that one possible solution is inflation with a sufficiently large Hubble rate, for this slow roll is not necessary. In addition, we also show that if the slow-roll condition is added to inflation with a large Hubble rate, then for any power law modified dispersion relation quantum vacuum fluctuations become nearly scale-invariant when they exit the Hubble radius.

Low-cyclic fatigue behavior of modified 9Cr–1Mo steel at elevated temperature

Energy Technology Data Exchange (ETDEWEB)

Guguloth, Krishna; Sivaprasad, S. [CSIR-National Metallurgical laboratory, Material Science and Technology Division, Jamshedpur 831007 (India); Chakrabarti, D. [Department of Metallurgical and Materials Engineering, Indian Institute of Technology, Kharagpur 721302 (India); Tarafder, S. [CSIR-National Metallurgical laboratory, Material Science and Technology Division, Jamshedpur 831007 (India)

2014-05-01

The low-cycle fatigue behavior of indigenously developed modified 9Cr–1Mo steel has been evaluated using a constant strain rate (1×10{sup −3} s{sup −1}) at ambient temperature (25 °C) and at elevated temperatures (500–600 °C) over the strain amplitudes varying between ±0.7% and ±1.2%. Cyclic stress response showed a gradual softening regime that ended in a stress plateau until complete failure of the specimens. The estimated fatigue life decreased with the increase in test temperature. The effect of temperature on fatigue life was more pronounced at lower strain amplitudes. The cyclic deformation behavior at different temperatures has been analyzed from hysteresis loop and also in view of the changes taking place in dislocation structure and dislocation–precipitation interaction. Evaluation of low-cycle fatigue properties of modified 9Cr–1Mo steel over a range of test temperature can help in designing components for in-core applications in fast breeder reactors and in super heaters for nuclear power plants.

Genomic mutational analysis of the impact of the classical strain improvement program on β-lactam producing Penicillium chrysogenum

NARCIS (Netherlands)

Salo, Oleksandr V; Ries, Marco; Medema, Marnix H; Lankhorst, Peter P; Vreeken, Rob J; Bovenberg, Roel A L; Driessen, Arnold J M

2015-01-01

BACKGROUND: Penicillium chrysogenum is a filamentous fungus that is employed as an industrial producer of β-lactams. The high β-lactam titers of current strains is the result of a classical strain improvement program (CSI) starting with a wild-type like strain more than six decades ago. This

Modified vaccinia virus Ankara protects macaques against respiratory challenge with monkeypox virus.

NARCIS (Netherlands)

K.J. Stittelaar (Koert); G. van Amerongen (Geert); I. Kondova (Ivanela); R.F. van Lavieren (Rob); F.H. Pistoor (Frank); H.G.M. Niesters (Bert); G.J.J. van Doornum (Gerard); B.A.M. van der Zeijst (Ben); L. Mateo (Luis); P.J. Chaplin (Paul); A.D.M.E. Osterhaus (Albert); T. Kuiken (Thijs)

2005-01-01

textabstractThe use of classical smallpox vaccines based on vaccinia virus (VV) is associated with severe complications in both naive and immune individuals. Modified vaccinia virus Ankara (MVA), a highly attenuated replication-deficient strain of VV, has been proven to be safe in humans and

New Lager Brewery Strains Obtained by Crossing Techniques Using Cachaça (Brazilian Spirit) Yeasts

Science.gov (United States)

Figueiredo, Bruna Inez Carvalho; Saraiva, Margarete Alice Fontes; de Souza Pimenta, Paloma Patrick; de Souza Testasicca, Miriam Conceição; Sampaio, Geraldo Magela Santos; da Cunha, Aureliano Claret; Afonso, Luis Carlos Crocco; Vieira de Queiroz, Marisa; de Miranda Castro, Ieso

2017-01-01

ABSTRACT The development of hybrids has been an effective approach to generate novel yeast strains with optimal technological profile for use in beer production. This study describes the generation of a new yeast strain for lager beer production by direct mating between two Saccharomyces cerevisiae strains isolated from cachaça distilleries: one that was strongly flocculent, and the other with higher production of acetate esters. The first step in this procedure was to analyze the sporulation ability and reproductive cycle of strains belonging to a specific collection of yeasts isolated from cachaça fermentation vats. Most strains showed high rates of sporulation, spore viability, and homothallic behavior. In order to obtain new yeast strains with desirable properties useful for lager beer production, we compare haploid-to-haploid and diploid-to-diploid mating procedures. Moreover, an assessment of parental phenotype traits showed that the segregant diploid C2-1d generated from a diploid-to-diploid mating experiment showed good fermentation performance at low temperature, high flocculation capacity, and desirable production of acetate esters that was significantly better than that of one type lager strain. Therefore, strain C2-1d might be an important candidate for the production of lager beer, with distinct fruit traces and originating using a non-genetically modified organism (GMO) approach. IMPORTANCE Recent work has suggested the utilization of hybridization techniques for the generation of novel non-genetically modified brewing yeast strains with combined properties not commonly found in a unique yeast strain. We have observed remarkable traits, especially low temperature tolerance, maltotriose utilization, flocculation ability, and production of volatile aroma compounds, among a collection of Saccharomyces cerevisiae strains isolated from cachaça distilleries, which allow their utilization in the production of beer. The significance of our research is in

Luminosity distance for Born-Infeld electromagnetic waves propagating in a cosmological magnetic background

Energy Technology Data Exchange (ETDEWEB)

Aiello, Matias; Bengochea, Gabriel R; Ferraro, Rafael, E-mail: aiello@iafe.uba.ar, E-mail: gabriel@iafe.uba.ar, E-mail: ferraro@iafe.uba.ar [Instituto de Astronomia y Fisica del Espacio, Casilla de Correo 67, Sucursal 28, 1428 Buenos Aires (Argentina); Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon I, 1428 Buenos Aires (Argentina)

2008-06-15

Born-Infeld electromagnetic waves interacting with a static magnetic background in an expanding universe are studied. The non-linear character of Born-Infeld electrodynamics modifies the relation between the energy flux and the distance to the source, which gains a new dependence on the redshift that is governed by the background field. We compute the luminosity distance as a function of the redshift and compare with Maxwellian curves for supernovae type Ia.

The influence of climatically-driven surface loading variations on continental strain and seismicity

Science.gov (United States)

Craig, Tim; Calais, Eric; Fleitout, Luce; Bollinger, Laurent; Scotti, Oona

2016-04-01

In slowly deforming regions of plate interiors, secondary sources of stress and strain can result in transient deformation rates comparable to, or greater than, the background tectonic rates. Highly variable in space and time, these transients have the potential to influence the spatio-temporal distribution of seismicity, interfering with any background tectonic effects to either promote or inhibit the failure of pre-existing faults, and potentially leading to a clustered, or 'pulse-like', seismic history. Here, we investigate the ways in which the large-scale deformation field resulting from climatically-controlled changes in surface ice mass over the Pleistocene and Holocene may have influenced not only the seismicity of glaciated regions, but also the wider seismicity around the ice periphery. We first use a set of geodynamic models to demonstrate that a major pulse of seismic activity occurring in Fennoscandia, coincident with the time of end-glaciation, occurred in a setting where the contemporaneous horizontal strain-rate resulting from the changing ice mass, was extensional - opposite to the reverse sense of coseismic displacement accommodated on these faults. Therefore, faulting did not release extensional elastic strain that was building up at the time of failure, but compressional elastic strain that had accumulated in the lithosphere on timescales longer than the glacial cycle, illustrating the potential for a non-tectonic trigger to tap in to the background tectonic stress-state. We then move on to investigate the more distal influence that changing ice (and ocean) volumes may have had on the evolving strain field across intraplate Europe, how this is reflected in the seismicity across intraplate Europe, and what impact this might have on the paleoseismic record.

Location specific in situ TEM straining specimens made using FIB

International Nuclear Information System (INIS)

Field, R.D.; Papin, P.A.

2004-01-01

A method has been devised and demonstrated for producing in situ straining specimens for the transmission electron microscope (TEM) from specific locations in a sample using a dual-beam focused ion beam (FIB) instrument. The specimen is removed from a polished surface in the FIB using normal methods and then attached to a pre-fabricated substrate in the form of a modified TEM tensile specimen. In this manner, specific features of the microstructure of a polished optical mount can be selected for in situ tensile straining. With the use of electron backscattered diffraction (EBSD), this technique could be extended to select specific orientations of the specimen as well

Strain-specific patterns of autonomic nervous system activity and heart failure susceptibility in mice.

Science.gov (United States)

Shusterman, Vladimir; Usiene, Irmute; Harrigal, Chivonne; Lee, Joon Sup; Kubota, Toru; Feldman, Arthur M; London, Barry

2002-06-01

Transgenic mice are widely used to study cardiac function, but strain-dependent differences in autonomic nervous system activity (ANSA) have not been explored. We compared 1) short-term pharmacological responses of cardiac rhythm in FVB vs. C57Black6/SV129 wild-type mice and 2) long-term physiological dynamics of cardiac rhythm and survival in tumor necrosis factor (TNF)-alpha transgenic mice with heart failure (TNF-alpha mice) on defined backgrounds. Ambulatory telemetry electrocardiographic recordings and response to saline, adrenergic, and cholinergic agents were examined in FVB and C57Black6/SV129 mice. In FVB mice, baseline heart rate (HR) was higher and did not change after injection of isoproterenol or atropine but decreased with propranolol. In C57Black6/SV129 mice, HR did not change with propranolol but increased with isoproterenol or atropine. Mean HR, but not indexes of HR variability, was an excellent predictor of response to autonomic agents. The proportion of surviving animals was higher in TNF-alpha mice on an FVB background than on a mixed FVB/C57Black6 background. The homeostatic states of ANSA are strain specific, which can explain the interstrain differences in mean HR, pharmacological responses, and survival of animals with congestive heart failure. Strain-specific differences should be considered in selecting the strains of mice used for transgenic and gene targeting experiments.

Gene expression cross-profiling in genetically modified industrial Saccharomyces cerevisiae strains during high-temperature ethanol production from xylose.

Science.gov (United States)

Ismail, Ku Syahidah Ku; Sakamoto, Takatoshi; Hatanaka, Haruyo; Hasunuma, Tomohisa; Kondo, Akihiko

2013-01-10

Production of ethanol from xylose at high temperature would be an economical approach since it reduces risk of contamination and allows both the saccharification and fermentation steps in SSF to be running at elevated temperature. Eight recombinant xylose-utilizing Saccharomyces cerevisiae strains developed from industrial strains were constructed and subjected to high-temperature fermentation at 38 °C. The best performing strain was sun049T, which produced up to 15.2 g/L ethanol (63% of the theoretical production), followed by sun048T and sun588T, both with 14.1 g/L ethanol produced. Via transcriptomic analysis, expression profiling of the top three best ethanol producing strains compared to a negative control strain, sun473T, led to the discovery of genes in common that were regulated in the same direction. Identification of the 20 most highly up-regulated and the 20 most highly down-regulated genes indicated that the cells regulate their central metabolism and maintain the integrity of the cell walls in response to high temperature. We also speculate that cross-protection in the cells occurs, allowing them to maintain ethanol production at higher concentration under heat stress than the negative controls. This report provides further transcriptomics information in the interest of producing a robust microorganism for high-temperature ethanol production utilizing xylose. Copyright © 2012 Elsevier B.V. All rights reserved.

Strain Tuning of the Charge Density Wave in Monolayer and Bilayer 1T-TaS2

KAUST Repository

Gan, Liyong

2015-12-07

By first-principles calculations, we investigate the strain effects on the charge density wave states of monolayer and bilayer 1T-TaS2. The modified stability of the charge density wave in the monolayer is understood in terms of the strain dependent electron localization, which determines the distortion amplitude. On the other hand, in the bilayer the effect of strain on the interlayer interaction is also crucial. The rich phase diagram under strain opens new venues for applications of 1T-TaS2. We interpret the experimentally observed insulating state of bulk 1T-TaS2 as inherited from the monolayer by effective interlayer decoupling.

Humans, Fish, and Whales: How Right Whales Modify Calling Behavior in Response to Shifting Background Noise Conditions.

Science.gov (United States)

Parks, Susan E; Groch, Karina; Flores, Paulo; Sousa-Lima, Renata; Urazghildiiev, Ildar R

2016-01-01

This study investigates the role of behavioral plasticity in the variation of sound production of southern right whales (Eubalaena australis) in response to changes in the ambient background noise conditions. Data were collected from southern right whales in Brazilian waters in October and November 2011. The goal of this study was to quantify differences in right whale vocalizations recorded in low background noise as a control, fish chorus noise, and vessel noise. Variation in call parameters were detected among the three background noise conditions and have implications for future studies of noise effects on whale sound production.

Novel effects of strains in graphene and other two dimensional materials

Energy Technology Data Exchange (ETDEWEB)

Amorim, B., E-mail: amorim.bac@icmm.csic.es [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain); Department of Physics and Center of Physics, University of Minho, P-4710-057, Braga (Portugal); Cortijo, A. [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain); Juan, F. de [Materials Science Division, Lawrence Berkeley National Laboratories, Berkeley, CA 94720 (United States); Department of Physics, University of California, Berkeley, CA 94720 (United States); Grushin, A.G. [Max-Planck-Institut fur Physik komplexer Systeme, 01187 Dresden (Germany); Guinea, F. [School of Physics and Astronomy, University of Manchester, Oxford Road, Manchester M13 9PL (United Kingdom); IMDEA Nanociencia Calle de Faraday, 9, Cantoblanco, 28049, Madrid (Spain); Donostia International Physics Center (DIPC), 20018 San Sebastián (Spain); Gutiérrez-Rubio, A. [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain); Ochoa, H. [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain); Donostia International Physics Center (DIPC), 20018 San Sebastián (Spain); Parente, V. [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain); IMDEA Nanociencia Calle de Faraday, 9, Cantoblanco, 28049, Madrid (Spain); Roldán, R.; San-Jose, P.; Schiefele, J. [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain); Sturla, M. [IFLP-CONICET. Departamento de Física, Universidad Nacional de La Plata, (1900) La Plata (Argentina); Vozmediano, M.A.H. [Instituto de Ciencia de Materiales de Madrid, CSIC, Cantoblanco, E-28049 Madrid (Spain)

2016-03-03

The analysis of the electronic properties of strained or lattice deformed graphene combines ideas from classical condensed matter physics, soft matter, and geometrical aspects of quantum field theory (QFT) in curved spaces. Recent theoretical and experimental work shows the influence of strains in many properties of graphene not considered before, such as electronic transport, spin–orbit coupling, the formation of Moiré patterns and optics. There is also significant evidence of anharmonic effects, which can modify the structural properties of graphene. These phenomena are not restricted to graphene, and they are being intensively studied in other two dimensional materials, such as the transition metal dichalcogenides. We review here recent developments related to the role of strains in the structural and electronic properties of graphene and other two dimensional compounds.

Antimicrobial Resistance of Staphylococcal Strains Isolated from Various Pathological Products

Directory of Open Access Journals (Sweden)

Laura-Mihaela SIMON

2010-12-01

Full Text Available Background: The optimal choice of antimicrobial therapy is an important problem in hospital environment in which the selection of resistant and virulent strains easy occurs. S. aureus and especially MRSA(methicillin-resistant S. aureus creates difficulties in both treatment and prevention of nosocomial infections. Aim: The purpose of this study is to determine the sensitivity and the resistance to chemotherapy of staphylococci strains isolated from various pathological products. Material and Method: We identified Staphylococccus species after morphological appearance, culture properties, the production of coagulase, hemolisines and the enzyme activity. The susceptibility tests were performed on Mueller-Hinton medium according to CLSI (Clinical and Laboratory Standards Institute. Results: The strains were: MSSA (methicillin-susceptible S. aureus (74%, MRSA (8%, MLS B (macrolides, lincosamides and type B streptogramines resistance (12% and MRSA and MLS B (6%. MRSA strains were more frequently isolated from sputum. MRSA associated with the MLS B strains were more frequently isolated from pus. MLS B strains were more frequently isolated from sputum and throat secretions. All S. aureus strains were susceptible to vancomycin and teicoplanin. Conclusions: All staphylococcal infections require resistance testing before treatment. MLS B shows a high prevalence among strains of S. aureus. The association between MLS B and MRSA remains a major problem in Romania.

Flow and failure of an aluminium alloy from low to high temperature and strain rate

Science.gov (United States)

Sancho, Rafael; Cendón, David; Gálvez, Francisco

2015-09-01

The mechanical behaviour of an aluminium alloy is presented in this paper. The study has been carried out to analyse the flow and failure of the aluminium alloy 7075-T73. An experimental study has been planned performing tests of un-notched and notched tensile specimens at low strain rates using a servo-hydraulic machine. High strain rate tests have been carried out using the same geometry in a Hopkinson Split Tensile Bar. The dynamic experiments at low temperature were performed using a cryogenic chamber, and the high temperature ones with a furnace, both incorporated to the Hopkinson bar. Testing temperatures ranged from - 50 ∘C to 100 ∘C and the strain rates from 10-4 s-1 to 600 s-1. The material behaviour was modelled using the Modified Johnson-Cook model and simulated using LS-DYNA. The results show that the Voce type of strain hardening is the most accurate for this material, while the traditional Johnson-Cook is not enough accurate to reproduce the necking of un-notched specimens. The failure criterion was obtained by means of the numerical simulations using the analysis of the stress triaxiality versus the strain to failure. The diameters at the failure time were measured using the images taken with an image camera, and the strain to failure was computed for un-notched and notched specimens. The numerical simulations show that the analysis of the evolution of the stress triaxiality is crucial to achieve accurate results. A material model using the Modified Johnson-Cook for flow and failure is proposed.

Interspecific competition between entomopathogenic nematodes (Steinernema is modified by their bacterial symbionts (Xenorhabdus

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Pages Sylvie

2006-09-01

Full Text Available Abstract Background Symbioses between invertebrates and prokaryotes are biological systems of particular interest in order to study the evolution of mutualism. The symbioses between the entomopathogenic nematodes Steinernema and their bacterial symbiont Xenorhabdus are very tractable model systems. Previous studies demonstrated (i a highly specialized relationship between each strain of nematodes and its naturally associated bacterial strain and (ii that mutualism plays a role in several important life history traits of each partner such as access to insect host resources, dispersal and protection against various biotic and abiotic factors. The goal of the present study was to address the question of the impact of Xenorhabdus symbionts on the progression and outcome of interspecific competition between individuals belonging to different Steinernema species. For this, we monitored experimental interspecific competition between (i two nematode species: S. carpocapsae and S. scapterisci and (ii their respective symbionts: X. nematophila and X. innexi within an experimental insect-host (Galleria mellonella. Three conditions of competition between nematodes were tested: (i infection of insects with aposymbiotic IJs (i.e. without symbiont of both species (ii infection of insects with aposymbiotic IJs of both species in presence of variable proportion of their two Xenorhabdus symbionts and (iii infection of insects with symbiotic IJs (i.e. naturally associated with their symbionts of both species. Results We found that both the progression and the outcome of interspecific competition between entomopathogenic nematodes were influenced by their bacterial symbionts. Thus, the results obtained with aposymbiotic nematodes were totally opposite to those obtained with symbiotic nematodes. Moreover, the experimental introduction of different ratios of Xenorhabdus symbionts in the insect-host during competition between Steinernema modified the proportion of

Fiber optic strain measurements using an optically-active polymer

Science.gov (United States)

Buckley, Leonard J.; Neumeister, Gary C.

1992-03-01

A study encompassing the use of an optically-active polymer as the strain-sensing medium in an organic matrix composite was performed. Several compounds were synthesized for use as the inner cladding material for silica fiber-optic cores. These materials include a diacetylene containing polyamide. It is possible to dynamically modify the optical properties of these materials through changes in applied strain or temperature. By doing so the characteristic absorption in the visible is reversibly shifted to a higher energy state. The polymer-coated fiber-optic cores were initially studied in epoxy resin. Additionally, one of the polyamide/diacetylene polymers was studied in a spin-fiber form consisting of 15 micron filaments assembled in multifilament tows. The most promising configuration and materials were then investigated further by embedding in graphite/epoxy composite laminates. In each case the shift in the visible absorption peak was monitored as a function of applied mechanical strain.

The influence of the anisotropic stress state on the intermediate strain properties of granular material

KAUST Repository

Goudarzy, M.; Kö nig, D.; Santamarina, Carlos; Schanz, T.

2017-01-01

This paper shows the effect of anisotropic stress state on intermediate strain properties of cylindrical samples containing spherical glass particles. Tests were carried out with the modified resonant column device available at Ruhr

Fatigue Life Prediction of High Modulus Asphalt Concrete Based on the Local Stress-Strain Method

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Mulian Zheng

2017-03-01

Full Text Available Previously published studies have proposed fatigue life prediction models for dense graded asphalt pavement based on flexural fatigue test. This study focused on the fatigue life prediction of High Modulus Asphalt Concrete (HMAC pavement using the local strain-stress method and direct tension fatigue test. First, the direct tension fatigue test at various strain levels was conducted on HMAC prism samples cut from plate specimens. Afterwards, their true stress-strain loop curves were obtained and modified to develop the strain-fatigue life equation. Then the nominal strain of HMAC course determined using finite element method was converted into local strain using the Neuber method. Finally, based on the established fatigue equation and converted local strain, a method to predict the pavement fatigue crack initiation life was proposed and the fatigue life of a typical HMAC overlay pavement which runs a risk of bottom-up cracking was predicted and validated. Results show that the proposed method was able to produce satisfactory crack initiation life.

Quantitative proteomic analyses of the microbial degradation of estrone under various background nitrogen and carbon conditions.

Science.gov (United States)

Du, Zhe; Chen, Yinguang; Li, Xu

2017-10-15

Microbial degradation of estrogenic compounds can be affected by the nitrogen source and background carbon in the environment. However, the underlying mechanisms are not well understood. The objective of this study was to elucidate the molecular mechanisms of estrone (E1) biodegradation at the protein level under various background nitrogen (nitrate or ammonium) and carbon conditions (no background carbon, acetic acid, or humic acid as background carbon) by a newly isolated bacterial strain. The E1 degrading bacterial strain, Hydrogenophaga atypica ZD1, was isolated from river sediments and its proteome was characterized under various experimental conditions using quantitative proteomics. Results show that the E1 degradation rate was faster when ammonium was used as the nitrogen source than with nitrate. The degradation rate was also faster when either acetic acid or humic acid was present in the background. Proteomics analyses suggested that the E1 biodegradation products enter the tyrosine metabolism pathway. Compared to nitrate, ammonium likely promoted E1 degradation by increasing the activities of the branched-chain-amino-acid aminotransferase (IlvE) and enzymes involved in the glutamine synthetase-glutamine oxoglutarate aminotransferase (GS-GOGAT) pathway. The increased E1 degradation rate with acetic acid or humic acid in the background can also be attributed to the up-regulation of IlvE. Results from this study can help predict and explain E1 biodegradation kinetics under various environmental conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Comparative genomics of koala, cattle and sheep strains of Chlamydia pecorum.

OpenAIRE

Bachmann, N.L.; Fraser, T.A.; Bertelli, C.; Jelocnik, M.; Gillett, A.; Funnell, O.; Flanagan, C.; Myers, G.S.; Timms, P.; Polkinghorne, A.

2014-01-01

Background Chlamydia pecorum is an important pathogen of domesticated livestock including sheep, cattle and pigs. This pathogen is also a key factor in the decline of the koala in Australia. We sequenced the genomes of three koala C. pecorum strains, isolated from the urogenital tracts and conjunctiva of diseased koalas. The genome of the C. pecorum VR629 (IPA) strain, isolated from a sheep with polyarthritis, was also sequenced. Results Comparisons of the draft C. pecorum genomes against the...

Discovery of a new strain of murine rotavirus that is consistently shed in large quantities after oral inoculation of adult mice

International Nuclear Information System (INIS)

McNeal, Monica M.; Belli, Janine; Basu, Mitali; Choi, Anthony H.-C.; Ward, Richard L.

2004-01-01

In 1990, we developed the adult mouse model for studies on active immunity against shedding of the EDIM strain of murine rotavirus. Low and inconsistent levels of EDIM shedding in some strains of adult mice, particularly those on C57BL/6 backgrounds, established the need for an alternative murine rotavirus strain for these studies. Fortuitously, such a rotavirus strain was obtained from mice housed within the conventional colony at Children's Hospital. This strain, named EMcN, was clearly distinguishable from EDIM based on electropherotype. Furthermore, sequence analyses of VP4 and VP7 genes of EMcN revealed non-identities in 5% of the amino acids of both proteins relative to EDIM but established EMcN as another G3P[16] strain of murine rotavirus. Subgroup analysis showed EMcN belonged to SG1 while EDIM was found to be non-SG1/SG2. Similarly, unlike EDIM, the EMcN strain was identified as serotype G3 based on neutralization by hyperimmune antisera developed against prototype human and simian G3 rotavirus strains. Although EDIM produced more days of diarrhea and was shed in greater quantities in neonatal BALB/c mice, EMcN was shed in much greater quantities in adult BALB/c mice. More importantly, in contrast to the EDIM strain, EMcN was shown to be consistently shed in large quantities in adult C57BL/6 mice and ko mice on this background. Therefore, it is recommended that the EMcN strain be used for future challenge studies with mice on this background

A modified parallel constitutive model for elevated temperature flow behavior of Ti-6Al-4V alloy based on multiple regression

Energy Technology Data Exchange (ETDEWEB)

Cai, Jun; Shi, Jiamin; Wang, Kuaishe; Wang, Wen; Wang, Qingjuan; Liu, Yingying [Xi' an Univ. of Architecture and Technology, Xi' an (China). School of Metallurgical Engineering; Li, Fuguo [Northwestern Polytechnical Univ., Xi' an (China). School of Materials Science and Engineering

2017-07-15

Constitutive analysis for hot working of Ti-6Al-4V alloy was carried out by using experimental stress-strain data from isothermal hot compression tests. A new kind of constitutive equation called a modified parallel constitutive model was proposed by considering the independent effects of strain, strain rate and temperature. The predicted flow stress data were compared with the experimental data. Statistical analysis was introduced to verify the validity of the developed constitutive equation. Subsequently, the accuracy of the proposed constitutive equations was evaluated by comparing with other constitutive models. The results showed that the developed modified parallel constitutive model based on multiple regression could predict flow stress of Ti-6Al-4V alloy with good correlation and generalization.

Strain analysis of nanowire interfaces in multiscale composites

Science.gov (United States)

Malakooti, Mohammad H.; Zhou, Zhi; Spears, John H.; Shankwitz, Timothy J.; Sodano, Henry A.

2016-04-01

Recently, the reinforcement-matrix interface of fiber reinforced polymers has been modified through grafting nanostructures - particularly carbon nanotubes and ZnO nanowires - on to the fiber surface. This type of interface engineering has made a great impact on the development of multiscale composites that have high stiffness, interfacial strength, toughness, and vibrational damping - qualities that are mutually exclusive to a degree in most raw materials. Although the efficacy of such nanostructured interfaces has been established, the reinforcement mechanisms of these multiscale composites have not been explored. Here, strain transfer across a nanowire interphase is studied in order to gain a heightened understanding of the working principles of physical interface modification and the formation of a functional gradient. This problem is studied using a functionally graded piezoelectric interface composed of vertically aligned lead zirconate titanate nanowires, as their piezoelectric properties can be utilized to precisely control the strain on one side of the interface. The displacement and strain across the nanowire interface is captured using digital image correlation. It is demonstrated that the material gradient created through nanowires cause a smooth strain transfer from reinforcement phase into matrix phase that eliminates the stress concentration between these phases, which have highly mismatched elasticity.

Job strain as a risk factor for clinical depression

DEFF Research Database (Denmark)

Madsen, I. E. H.; Nyberg, S. T.; Magnusson Hanson, L. L.

2017-01-01

BACKGROUND: Adverse psychosocial working environments characterized by job strain (the combination of high demands and low control at work) are associated with an increased risk of depressive symptoms among employees, but evidence on clinically diagnosed depression is scarce. We examined job strain...... as a risk factor for clinical depression. METHOD: We identified published cohort studies from a systematic literature search in PubMed and PsycNET and obtained 14 cohort studies with unpublished individual-level data from the Individual-Participant-Data Meta-analysis in Working Populations (IPD...... unpublished datasets we included 120 221 individuals and 982 first episodes of hospital-treated clinical depression. Job strain was associated with an increased risk of clinical depression in both published [relative risk (RR) = 1.77, 95% confidence interval (CI) 1.47-2.13] and unpublished datasets (RR = 1...

Modified Displacement Transfer Functions for Deformed Shape Predictions of Slender Curved Structures with Varying Curvatives

Science.gov (United States)

Ko, William L.; Fleischer, Van Tran

2014-01-01

To eliminate the need to use finite-element modeling for structure shape predictions, a new method was invented. This method is to use the Displacement Transfer Functions to transform the measured surface strains into deflections for mapping out overall structural deformed shapes. The Displacement Transfer Functions are expressed in terms of rectilinearly distributed surface strains, and contain no material properties. This report is to apply the patented method to the shape predictions of non-symmetrically loaded slender curved structures with different curvatures up to a full circle. Because the measured surface strains are not available, finite-element analysis had to be used to analytically generate the surface strains. Previously formulated straight-beam Displacement Transfer Functions were modified by introducing the curvature-effect correction terms. Through single-point or dual-point collocations with finite-elementgenerated deflection curves, functional forms of the curvature-effect correction terms were empirically established. The resulting modified Displacement Transfer Functions can then provide quite accurate shape predictions. Also, the uniform straight-beam Displacement Transfer Function was applied to the shape predictions of a section-cut of a generic capsule (GC) outer curved sandwich wall. The resulting GC shape predictions are quite accurate in partial regions where the radius of curvature does not change sharply.

Probiotic features of Lactobacillus plantarum mutant strains.

Science.gov (United States)

Bove, Pasquale; Gallone, Anna; Russo, Pasquale; Capozzi, Vittorio; Albenzio, Marzia; Spano, Giuseppe; Fiocco, Daniela

2012-10-01

In this study, the probiotic potential of Lactobacillus plantarum wild-type and derivative mutant strains was investigated. Bacterial survival was evaluated in an in vitro system, simulating the transit along the human oro-gastro-intestinal tract. Interaction with human gut epithelial cells was studied by assessing bacterial adhesive ability to Caco-2 cells and induction of genes involved in innate immunity. L. plantarum strains were resistant to the combined stress at the various steps of the simulated gastrointestinal tract. Major decreases in the viability of L. plantarum cells were observed mainly under drastic acidic conditions (pH ≤ 2.0) of the gastric compartment. Abiotic stresses associated to small intestine poorly affected bacterial viability. All the bacterial strains significantly adhered to Caco-2 cells, with the ΔctsR mutant strain exhibiting the highest adhesion. Induction of immune-related genes resulted higher upon incubation with heat-inactivated bacteria rather than with live ones. For specific genes, a differential transcriptional pattern was observed upon stimulation with different L. plantarum strains, evidencing a possible role of the knocked out bacterial genes in the modulation of host cell response. In particular, cells from Δhsp18.55 and ΔftsH mutants strongly triggered immune defence genes. Our study highlights the relevance of microbial genetic background in host-probiotic interaction and might contribute to identify candidate bacterial genes and molecules involved in probiosis.

Sequencing and characterization of Varicella-Zoster virus vaccine strain SuduVax

Directory of Open Access Journals (Sweden)

Kim Jong

2011-12-01

Full Text Available Abstract Background Varicella-zoster virus (VZV causes chickenpox in children and shingles in older people. Currently, live attenuated vaccines based on the Oka strain are available worldwide. In Korea, an attenuated VZV vaccine has been developed from a Korean isolate and has been commercially available since 1994. Despite this long history of use, the mechanism for the attenuation of the vaccine strain is still elusive. We attempted to understand the molecular basis of attenuation mechanism by full genome sequencing and comparative genomic analyses of the Korean vaccine strain SuduVax. Results SuduVax was found to contain a genome that was 124,759 bp and possessed 74 open reading frames (ORFs. SuduVax was genetically most close to Oka strains and these Korean-Japanese strains formed a strong clade in phylogenetic trees. SuduVax, similar to the Oka vaccine strains, underwent T- > C substitution at the stop codon of ORF0, resulting in a read-through mutation to code for an extended form of ORF0 protein. SuduVax also shared certain deletion and insertion mutations in ORFs 17, 29, 56 and 60 with Oka vaccine strains and some clinical strains. Conclusions The Korean VZV vaccine strain SuduVax is genetically similar to the Oka vaccine strains. Further comparative genomic and bioinformatics analyses will help to elucidate the molecular basis of the attenuation of the VZV vaccine strains.

Handheld Delivery System for Modified Boron-Type Fire Extinguishment Agent

Science.gov (United States)

1993-11-01

was to develop and test a handheld portable delivery system for use with the modified boron-type fire extinguishing agent for metal fires . B...BACKGROUND A need exists for an extinguishing agent and accompanying delivery system that are effective against complex geometry metal fires . A modified...agent and its delivery system have proven effective against complex geometry metal fires containing up to 200 pounds of magnesium metal. Further

Biotechnology: Two Decades of Experimentation with Genetically Modified Foods

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Marjan Ajami

2016-10-01

Full Text Available Background and Objective: Over the recent years, genetically modified food in varieties of corn, soybeans, canola and cotton have been introduced to the global market. This study reviews the health and nutritional value of genetically modified foods in the past two decades.Results and Conclusions: Contrary to the present biotechnological claims, transgenic products did not prove to be so flawless, and actually failed to maintain social satisfaction. Genetically modified foods could not gain an increase in the yield potential. Planting natural products and genetically modified products in parallel lines will absolutely result in genetic infection from the side of genetically modified foods. One of the major anxieties of the anti- genetically modified foods activism is the claim that genetically modified crops would alter the consumable parts of the plant quality and safety. Genetically modified foods have shown to have inadequate efficiency and potential adverse effects in both fields of health and biodiversity. This review has presented studies of genetically modified foods performances in the past two decades, and concludes that the wide application and the over generalization of genetically modified foods are not fundamentally recommended.Conflict of interest: Authors declare that there is no conflict of interest.

Socioeconomic and modifiable predictors of blood pressure control ...

African Journals Online (AJOL)

Background. Low socioeconomic status is associated with the risk of hypertension. There are few reports of the effect of socioeconomic and potentially modifiable factors on the control of hypertension in South Africa (SA). Objectives. To investigate associations between patients' socioeconomic status and characteristics of ...

Job Strain and Cognitive Decline: A Prospective Study of the Framingham Offspring Cohort

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W Agbenyikey

2015-04-01

Full Text Available Background: Workplace stress is known to be related with many behavioral and disease outcomes. However, little is known about its prospective relationship with measures of cognitive decline. Objective: To investigate the association of job strain, psychological demands and job control on cognitive decline. Methods: Participants from Framingham Offspring cohort (n=1429, were assessed on job strain, and received neuropsychological assessment approximately 15 years and 21 years afterwards. Results: High job strain and low control were associated with decline in verbal learning and memory. Job strain was associated with decline in word recognition skills. Active job and passive job predicted decline in verbal learning and memory relative to low strain jobs in the younger subgroup. Active job and demands were positively associated with abstract reasoning skills. Conclusions: Job strain and job control may influence decline in cognitive performance.

Characterization of Staphylococcus aureus strains involved in human and bovine mastitis.

Science.gov (United States)

Delgado, Susana; García, Pilar; Fernández, Leonides; Jiménez, Esther; Rodríguez-Baños, Mercedes; del Campo, Rosa; Rodríguez, Juan M

2011-07-01

Staphylococcus aureus is one of the main etiological agents of mastitis in different mammalian species. At present, it is unknown whether strains isolated from human mastitis cases share phenotypic properties and genetic background with those obtained from animal mastitis cases. Therefore, the objective of this study was to characterize S. aureus strains isolated from women with lactational mastitis and to compare them with the strains responsible for bovine mastitis and noninfectious strains. All the strains were genotyped by both pulsed field gel electrophoresis and multilocus sequence typing and submitted to a characterization scheme that included diverse assays related to pathogenic potential and antibiotic resistance. Apart from siderophore production, no significant association was observed between the strains from bovine and human mastitis. Statistical differences between human- and bovine-mastitis-associated strains were detected for some traits and virulence determinants, such as the presence of prophages and cna and hlb genes, which were more frequently found within the bovine group. On the contrary, resistance to penicillin was significantly higher among strains isolated from human lactational mastitis, probably related to the common presence of the blaZ gene. A high genetic diversity was found among the strains involved in mastitis in breastfeeding women. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

BCG strain S4-Jena: An early BCG strain is capable to reduce the proliferation of bladder cancer cells by induction of apoptosis

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Hermann Inge-Marie

2010-06-01

Full Text Available Abstract Background Intravesical immunotherapy with Mycobacterium bovis bacillus Calmette-Guérin has been established as the most effective adjuvant treatment for high risk non-muscle-invasive bladder cancer (NMIBC. We investigated the differences between the S4-Jena BCG strain and commercially available BCG strains. We tested the genotypic varieties between S4-Jena and other BCG strains and analysed the effect of the BCG strains TICE and S4-Jena on two bladder cancer cell lines. Results In contrast to commercially available BCG strains the S4-Jena strain shows genotypic differences. Spoligotyping verifies the S4-Jena strain as a BCG strain. Infection with viable S4-Jena or TICE decreased proliferation in the T24 cell line. Additionally, hallmarks of apoptosis were detectable. In contrast, Cal29 cells showed only a slightly decreased proliferation with TICE. Cal29 cells infected with S4-Jena, though, showed a significantly decreased proliferation in contrast to TICE. Concordantly with these results, infection with TICE had no effect on the morphology and hallmarks of apoptosis of Cal29 cells. However, S4-Jena strain led to clearly visible morphological changes and caspases 3/7 activation and PS flip. Conclusions S4-Jena strain has a direct influence on bladder cancer cell lines as shown by inhibition of cell proliferation and induction of apoptosis. The data implicate that the T24 cells are responder for S4-Jena and TICE BCG. However, the Cal29 cells are only responder for S4-Jena and they are non-responder for TICE BCG. S4-Jena strain may represent an effective therapeutic agent for NMIBC.

Genomic mutational analysis of the impact of the classical strain improvement program on ß–lactam producing Penicillium chrysogenum

NARCIS (Netherlands)

Salo, O.V.; Ries, M.; Medema, M.H.; Lankhorst, P.P.; Vreeken, R.J.; Bovenberg, R.A.L.; Driessen, A.J.M.

2015-01-01

Background Penicillium chrysogenum is a filamentous fungus that is employed as an industrial producer of ß–lactams. The high ß–lactam titers of current strains is the result of a classical strain improvement program (CSI) starting with a wild-type like strain more than six decades ago. This involved

Constitutive relationships of hot stamping boron steel B1500HS based on the modified Arrhenius and Johnson–Cook model

International Nuclear Information System (INIS)

Li, Huiping; He, Lianfang; Zhao, Guoqun; Zhang, Lei

2013-01-01

Constitutive relationship of boron steel is one of the most necessary mathematical models in the numerical simulation of hot stamping; it describes the relationship of the flow stress with strain, strain rate and temperature. In order to attain the constitutive relationship of boron steel B1500HS, four types of samples with microstructure of austenite, ferrite+pearlite, bainite or martensite are prepared by the Gleeble 1500D thermo-mechanical simulator. Isothermal uniaxial tension testings for these specimens are performed at 20–900 °C at the strain rates of 0.01 s –1 , 0.1 s –1 , 1.0 s –1 and 10 s –1 by Gleeble 1500D, and the true stress–strain curves at the relative conditions are gained. The experimental results show that, the flow stress of samples with relative microstructure rises with the decrease of the deformation temperature, and with the increase of the strain rate. The modified Arrhenius model is used to describe the hot deformation of samples with austenite microstructure, and the modified Johnson–Cook model is used to describe the deformation process of samples with ferrite+pearlite, bainite or martensite microstructure. The constitutive equations depending on the strain, strain rate and temperature are attained by the regression analysis for the experimental data of flow stress, strain, strain rate, temperature, etc. The comparison of the computational data and the experimental results shows that, the computational data using the constitutive relationships are well consistent with the experimental data

Genotypic comparison of Pantoea agglomerans plant and clinical strains

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Frey Jürg E

2009-09-01

Full Text Available Abstract Background Pantoea agglomerans strains are among the most promising biocontrol agents for a variety of bacterial and fungal plant diseases, particularly fire blight of apple and pear. However, commercial registration of P. agglomerans biocontrol products is hampered because this species is currently listed as a biosafety level 2 (BL2 organism due to clinical reports as an opportunistic human pathogen. This study compares plant-origin and clinical strains in a search for discriminating genotypic/phenotypic markers using multi-locus phylogenetic analysis and fluorescent amplified fragment length polymorphisms (fAFLP fingerprinting. Results Majority of the clinical isolates from culture collections were found to be improperly designated as P. agglomerans after sequence analysis. The frequent taxonomic rearrangements underwent by the Enterobacter agglomerans/Erwinia herbicola complex may be a major problem in assessing clinical associations within P. agglomerans. In the P. agglomerans sensu stricto (in the stricter sense group, there was no discrete clustering of clinical/biocontrol strains and no marker was identified that was uniquely associated to clinical strains. A putative biocontrol-specific fAFLP marker was identified only in biocontrol strains. The partial ORF located in this band corresponded to an ABC transporter that was found in all P. agglomerans strains. Conclusion Taxonomic mischaracterization was identified as a major problem with P. agglomerans, and current techniques removed a majority of clinical strains from this species. Although clear discrimination between P. agglomerans plant and clinical strains was not obtained with phylogenetic analysis, a single marker characteristic of biocontrol strains was identified which may be of use in strain biosafety determinations. In addition, the lack of Koch's postulate fulfilment, rare retention of clinical strains for subsequent confirmation, and the polymicrobial nature of P

A Study of the Mechanical Behavior of OFHC Copper in Tension at Various Strain Rates and Heating Rates Using the Two-Dimensional Integrated Speckle Measuring System

National Research Council Canada - National Science Library

Durant, Brian

2000-01-01

.... A modified dog bone specimen was heated using resistive heating techniques. The effects of high temperature, medium strain rates, and high heating rates on the stress-strain results were observed...

Comparison of Bacterial Cellulose Production among Different Strains and Fermented Media

Directory of Open Access Journals (Sweden)

Maryam Jalili Tabaii

2015-12-01

Full Text Available The effect of different carbon sources on bacterial cellulose production by Gluconacetobacter xylinus (PTCC 1734 and two newly isolated strains (from vinegar under static culture conditions was studied. The production of bacterial cellulose was examined in modified Hestrin-Shramm medium by replacing D-glucose with other carbon sources. The results showed that the yield and characteristics of bacterial cellulose were influenced by the type of carbon source. Glycerol gave the highest yield in all of the studied strains (6%, 9.7% and 3.8% for S, A2 strain and Gluconacetobacter xylinus (PTCC 1734, respectively. The maximum dry bacterial cellulose weight in the glycerol containing medium is due to A2 strain (1.9 g l-1 in comparison to Gluconacetobacter xylinus as reference strain (0.76 g l-1. Although all of the studied strains were in Gluconacetobacter family, each used different sugars for maximum production after glycerol (mannitol and fructose for two newly isolated strains and glucose for Gluconacetobacter xylinus. The maximum moisture content was observed when sucrose and food-grade sucrose were used as carbon source. Contrary to expectations, while the maximum thickness of bacterial cellulose membrane was attained when glycerol was used, bacterial cellulose from glycerol had less moisture content than the others. The oxidized cellulose showed antibacterial activities, which makes it as a good candidate for food-preservatives.

Persistence of Pathogenic and Non-Pathogenic Escherichia coli Strains in Various Tropical Agricultural Soils of India.

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S Naganandhini

Full Text Available The persistence of Shiga-like toxin producing E. coli (STEC strains in the agricultural soil creates serious threat to human health through fresh vegetables growing on them. However, the survival of STEC strains in Indian tropical soils is not yet understood thoroughly. Additionally how the survival of STEC strain in soil diverges with non-pathogenic and genetically modified E. coli strains is also not yet assessed. Hence in the present study, the survival pattern of STEC strain (O157-TNAU was compared with non-pathogenic (MTCC433 and genetically modified (DH5α strains on different tropical agricultural soils and on a vegetable growing medium, cocopeat under controlled condition. The survival pattern clearly discriminated DH5α from MTCC433 and O157-TNAU, which had shorter life (40 days than those compared (60 days. Similarly, among the soils assessed, the red laterite and tropical latosol supported longer survival of O157-TNAU and MTCC433 as compared to wetland and black cotton soils. In cocopeat, O157 recorded significantly longer survival than other two strains. The survival data were successfully analyzed using Double-Weibull model and the modeling parameters were correlated with soil physico-chemical and biological properties using principal component analysis (PCA. The PCA of all the three strains revealed that pH, microbial biomass carbon, dehydrogenase activity and available N and P contents of the soil decided the survival of E. coli strains in those soils and cocopeat. The present research work suggests that the survival of O157 differs in tropical Indian soils due to varied physico-chemical and biological properties and the survival is much shorter than those reported in temperate soils. As the survival pattern of non-pathogenic strain, MTCC433 is similar to O157-TNAU in tropical soils, the former can be used as safe model organism for open field studies.

Kinetics of spontaneous baryogenesis in non-stationary background

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Arbuzova Elena

2016-01-01

Full Text Available Generation of the cosmological baryon asymmetry in frameworks of spontaneous baryogenesis is studied in detail. It is shown that the relation between baryonic chemical potential and the time derivative of the (pseudoGoldstone field essentially depends upon the representation chosen for the fermionic fields with non-zero baryonic number (quarks. Kinetic equation is modified and numerically solved in equilibrium for the case of time dependent external background or finite integration time to be applicable to the case when energy conservation law is formally violated.

Transcriptional Regulation and the Diversification of Metabolism in Wine Yeast Strains

Science.gov (United States)

Rossouw, Debra; Jacobson, Dan; Bauer, Florian F.

2012-01-01

Transcription factors and their binding sites have been proposed as primary targets of evolutionary adaptation because changes to single transcription factors can lead to far-reaching changes in gene expression patterns. Nevertheless, there is very little concrete evidence for such evolutionary changes. Industrial wine yeast strains, of the species Saccharomyces cerevisiae, are a geno- and phenotypically diverse group of organisms that have adapted to the ecological niches of industrial winemaking environments and have been selected to produce specific styles of wine. Variation in transcriptional regulation among wine yeast strains may be responsible for many of the observed differences and specific adaptations to different fermentative conditions in the context of commercial winemaking. We analyzed gene expression profiles of wine yeast strains to assess the impact of transcription factor expression on metabolic networks. The data provide new insights into the molecular basis of variations in gene expression in industrial strains and their consequent effects on metabolic networks important to wine fermentation. We show that the metabolic phenotype of a strain can be shifted in a relatively predictable manner by changing expression levels of individual transcription factors, opening opportunities to modify transcription networks to achieve desirable outcomes. PMID:22042577

Fermentation of oat and soybean hull hydrolysates into ethanol and xylitol by recombinant industrial strains of Saccharomyces cerevisiae under diverse oxygen environments

Science.gov (United States)

In this study, we evaluated the capacity of recombinant industrial Saccharomyces cerevisiae YRH 396 and YRH 400 strains to ferment sugars from oat hull and soybean hull hydrolysates into ethanol and xylitol. The strains were genetically modified by chromosomal integration of Pichia stipitis XYLI/XYL...

Deinococcus radiodurans strain R1 contains N6-methyladenine in its genome

International Nuclear Information System (INIS)

Prasad, Bhaskar Jyoti; Sabnis, Ketaki; Deobagkar, Deepti D.; Deobagkar, Dileep N.

2005-01-01

Methylation of DNA is known to be involved in DNA repair mechanisms in bacteria. Deinococcus radiodurans strain R1 on exposure to high radiation undergoes significant DNA damage, which is repaired without mutations. However, the presence of modified nucleotides has not been reported in its genome. We report here the detection of N6-methyladenine in the genome of D. radiodurans strain R1 using immunochemical techniques. This N6-methyladenine is not a part of GATC restriction-modification system. D. radiodurans cell extract also exhibited a DNA adenine methyltransferase activity which was reduced in the early post-irradiation recovery phase

Weak lensing probes of modified gravity

International Nuclear Information System (INIS)

Schmidt, Fabian

2008-01-01

We study the effect of modifications to general relativity on large-scale weak lensing observables. In particular, we consider three modified gravity scenarios: f(R) gravity, the Dvali-Gabadadze-Porrati model, and tensor-vector-scalar theory. Weak lensing is sensitive to the growth of structure and the relation between matter and gravitational potentials, both of which will in general be affected by modified gravity. Restricting ourselves to linear scales, we compare the predictions for galaxy-shear and shear-shear correlations of each modified gravity cosmology to those of an effective dark energy cosmology with the same expansion history. In this way, the effects of modified gravity on the growth of perturbations are separated from the expansion history. We also propose a test which isolates the matter-potential relation from the growth factor and matter power spectrum. For all three modified gravity models, the predictions for galaxy and shear correlations will be discernible from those of dark energy with very high significance in future weak lensing surveys. Furthermore, each model predicts a measurably distinct scale dependence and redshift evolution of galaxy and shear correlations, which can be traced back to the physical foundations of each model. We show that the signal-to-noise for detecting signatures of modified gravity is much higher for weak lensing observables as compared to the integrated Sachs-Wolfe effect, measured via the galaxy-cosmic microwave background cross-correlation.

Characterization of a mouse-adapted Staphylococcus aureus strain.

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Silva Holtfreter

Full Text Available More effective antibiotics and a protective vaccine are desperately needed to combat the 'superbug' Staphylococcus aureus. While in vivo pathogenicity studies routinely involve infection of mice with human S. aureus isolates, recent genetic studies have demonstrated that S. aureus lineages are largely host-specific. The use of such animal-adapted S. aureus strains may therefore be a promising approach for developing more clinically relevant animal infection models. We have isolated a mouse-adapted S. aureus strain (JSNZ which caused a severe outbreak of preputial gland abscesses among male C57BL/6J mice. We aimed to extensively characterize this strain on a genomic level and determine its virulence potential in murine colonization and infection models. JSNZ belongs to the MLST type ST88, rare among human isolates, and lacks an hlb-converting phage encoding human-specific immune evasion factors. Naive mice were found to be more susceptible to nasal and gastrointestinal colonization with JSNZ than with the human-derived Newman strain. Furthermore, naïve mice required antibiotic pre-treatment to become colonized with Newman. In contrast, JSNZ was able to colonize mice in the absence of antibiotic treatment suggesting that this strain can compete with the natural flora for space and nutrients. In a renal abscess model, JSNZ caused more severe disease than Newman with greater weight loss and bacterial burden. In contrast to most other clinical isolates, JSNZ can also be readily genetically modified by phage transduction and electroporation. In conclusion, the mouse-adapted strain JSNZ may represent a valuable tool for studying aspects of mucosal colonization and for screening novel vaccines and therapies directed at preventing colonization.

The Effect of Grain Size and Strain on the Tensile Flow Stress of Aluminium at Room Temperature

DEFF Research Database (Denmark)

Hansen, Niels

1977-01-01

stress-grain size relationship was analyzed in terms of matrix strengthening and grain boundary strengthening according to the dislocation concept of Ashby. At intermediate strains this approach gives a good description of the effect of strain, grain size and purity on the flow stress.......Tensile-stress-strain data over a strain range from 0.2 to 30% were obtained at room temperature for 99.999 and 99.5% aluminium as a function of grain size. The yield stress-grain size relationship can be expressed by a Petch-Hall relation with approximately the same slope for the two materials....... The flow stress-grain size relationship can adequately be expressed by a modified Petch-Hall relation; for 99.999% aluminium material the slope increases with strain through a maximum around 15–20%, whereas for 99.5% aluminium the slope decreases with the strain to zero at strains about 10%. The flow...

A trans-acting Variant within the Transcription Factor RIM101 Interacts with Genetic Background to Determine its Regulatory Capacity.

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Timothy Read

2016-01-01

Full Text Available Most genetic variants associated with disease occur within regulatory regions of the genome, underscoring the importance of defining the mechanisms underlying differences in regulation of gene expression between individuals. We discovered a pair of co-regulated, divergently oriented transcripts, AQY2 and ncFRE6, that are expressed in one strain of Saccharomyces cerevisiae, ∑1278b, but not in another, S288c. By combining classical genetics techniques with high-throughput sequencing, we identified a trans-acting single nucleotide polymorphism within the transcription factor RIM101 that causes the background-dependent expression of both transcripts. Subsequent RNA-seq experiments revealed that RIM101 regulates many more targets in S288c than in ∑1278b and that deletion of RIM101 in both backgrounds abrogates the majority of differential expression between the strains. Strikingly, only three transcripts undergo a significant change in expression after swapping RIM101 alleles between backgrounds, implying that the differences in the RIM101 allele lead to a remarkably focused transcriptional response. However, hundreds of RIM101-dependent targets undergo a subtle but consistent shift in expression in the S288c RIM101-swapped strain, but not its ∑1278b counterpart. We conclude that ∑1278b may harbor a variant(s that buffers against widespread transcriptional dysregulation upon introduction of a non-native RIM101 allele, emphasizing the importance of accounting for genetic background when assessing the impact of a regulatory variant.

An efficient genotyping method for genome-modified animals and human cells generated with CRISPR/Cas9 system.

Science.gov (United States)

Zhu, Xiaoxiao; Xu, Yajie; Yu, Shanshan; Lu, Lu; Ding, Mingqin; Cheng, Jing; Song, Guoxu; Gao, Xing; Yao, Liangming; Fan, Dongdong; Meng, Shu; Zhang, Xuewen; Hu, Shengdi; Tian, Yong

2014-09-19

The rapid generation of various species and strains of laboratory animals using CRISPR/Cas9 technology has dramatically accelerated the interrogation of gene function in vivo. So far, the dominant approach for genotyping of genome-modified animals has been the T7E1 endonuclease cleavage assay. Here, we present a polyacrylamide gel electrophoresis-based (PAGE) method to genotype mice harboring different types of indel mutations. We developed 6 strains of genome-modified mice using CRISPR/Cas9 system, and utilized this approach to genotype mice from F0 to F2 generation, which included single and multiplexed genome-modified mice. We also determined the maximal detection sensitivity for detecting mosaic DNA using PAGE-based assay as 0.5%. We further applied PAGE-based genotyping approach to detect CRISPR/Cas9-mediated on- and off-target effect in human 293T and induced pluripotent stem cells (iPSCs). Thus, PAGE-based genotyping approach meets the rapidly increasing demand for genotyping of the fast-growing number of genome-modified animals and human cell lines created using CRISPR/Cas9 system or other nuclease systems such as TALEN or ZFN.

Comparative genomic analyses of Mycoplasma hyopneumoniae pathogenic 168 strain and its high-passaged attenuated strain

Science.gov (United States)

2013-01-01

Background Mycoplasma hyopneumoniae is the causative agent of porcine enzootic pneumonia (EP), a mild, chronic pneumonia of swine. Despite presenting with low direct mortality, EP is responsible for major economic losses in the pig industry. To identify the virulence-associated determinants of M. hyopneumoniae, we determined the whole genome sequence of M. hyopneumoniae strain 168 and its attenuated high-passage strain 168-L and carried out comparative genomic analyses. Results We performed the first comprehensive analysis of M. hyopneumoniae strain 168 and its attenuated strain and made a preliminary survey of coding sequences (CDSs) that may be related to virulence. The 168-L genome has a highly similar gene content and order to that of 168, but is 4,483 bp smaller because there are 60 insertions and 43 deletions in 168-L. Besides these indels, 227 single nucleotide variations (SNVs) were identified. We further investigated the variants that affected CDSs, and compared them to reported virulence determinants. Notably, almost all of the reported virulence determinants are included in these variants affected CDSs. In addition to variations previously described in mycoplasma adhesins (P97, P102, P146, P159, P216, and LppT), cell envelope proteins (P95), cell surface antigens (P36), secreted proteins and chaperone protein (DnaK), mutations in genes related to metabolism and growth may also contribute to the attenuated virulence in 168-L. Furthermore, many mutations were located in the previously described repeat motif, which may be of primary importance for virulence. Conclusions We studied the virulence attenuation mechanism of M. hyopneumoniae by comparative genomic analysis of virulent strain 168 and its attenuated high-passage strain 168-L. Our findings provide a preliminary survey of CDSs that may be related to virulence. While these include reported virulence-related genes, other novel virulence determinants were also detected. This new information will form

A comparative study concerning the pigments from two Monascus strains obtained by radio-mutagenesis

International Nuclear Information System (INIS)

Ferdes, M.; Mencinicopschi, G.; Ferdes, O.

1995-01-01

Monascus ruber ICA 3.250 spores suspension was gamma-irradiated at a Co-60 gamma-ray source at doses D=1 to 10 kGy. After dilution it has drown the survival curve and there were isolated two mutant strains, M 1 and M 2 . These were investigated with regard to food red pigment production on solid and liquid submerged (with aeration and stirring) culture media. In comparison with the parental (control strain, the two mutant strains M 1 and M 2 show morphological and physiological modified characteristics which led both to the increase in pigment concentration in culture media and in the reduction of biosynthesis duration. (Author) 3 Figs., 2 Tabs., 11 Refs

Genetic modification of glaucoma associated phenotypes between AKXD-28/Ty and DBA/2J mice

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Zabaleta Adriana

2001-01-01

Full Text Available Abstract Background Glaucoma is a common disease but its molecular etiology is poorly understood. It involves retinal ganglion cell death and optic nerve damage that is often associated with elevated intraocular pressure. Identifying genes that modify glaucoma associated phenotypes is likely to provide insights to mechanisms of glaucoma. We previously reported glaucoma in DBA/2J mice caused by recessive alleles at two loci, isa and ipd, that cause iris stromal atrophy and iris pigment dispersion, respectively. A approach for identifying modifier genes is to study the effects of specific mutations in different mouse strains. When the phenotypic effect of a mutation is modified upon its introduction into a new strain, crosses between the parental strains can be used to identify modifier genes. The purpose of this study was to determine if the effects of the DBA/2J derived isa and ipd loci are modified in strain AKXD-28/Ty. Results AKXD-28/Ty mice develop glaucoma characterized by intraocular pressure elevation, retinal ganglion loss, and optic nerve excavation. In AKXD-28/Ty, isa causes an iris stromal atrophy phenotype as in DBA/2J. However, the iris pigment dispersion phenotype associated with ipd in DBA/2J does not occur in AKXD-28/Ty. Additionally, a greater severity and speed of retinal and optic nerve damage following intraocular pressure elevation in AKXD-28/Ty compared to DBA/2J mice suggests that AKXD-28/Ty is more susceptible to pressure-induced cell death. Conclusions The consequences of the ipd and isa mutations are modified in the AKXD-28/Ty background. These strains provide a resource for the identification of modifier genes that modulate pigment dispersion and susceptibility to pressure-induced cell death.

Modifying Post-Operative Medical Care after EBV Implant May Reduce Pneumothorax Incidence.

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Dominik Herzog

Full Text Available Endoscopic lung volume reduction (ELVR with valves has been shown to improve COPD patients with severe emphysema. However, a major complication is pneumothoraces, occurring typically soon after valve implantation, with severe consequences if not managed promptly. Based on the knowledge that strain activity is related to a higher risk of pneumothoraces, we asked whether modifying post-operative medical care with the inclusion of strict short-term limitation of strain activity is associated with a lower incidence of pneumothorax.Seventy-two (72 emphysematous patients without collateral ventilation were treated with bronchial valves and included in the study. Thirty-two (32 patients received standard post-implantation medical management (Standard Medical Care (SMC, and 40 patients received a modified medical care that included an additional bed rest for 48 hours and cough suppression, as needed (Modified Medical Care (MMC.The baseline characteristics were similar for the two groups, except there were more males in the SMC cohort. Overall, ten pneumothoraces occurred up to four days after ELVR, eight pneumothoraces in the SMC, and only two in the MMC cohorts (p=0.02. Complicated pneumothoraces and pneumothoraces after upper lobe treatment were significantly lower in MMC (p=0.02. Major clinical outcomes showed no significant differences between the two cohorts.In conclusion, modifying post-operative medical care to include bed rest for 48 hours after ELVR and cough suppression, if needed, might reduce the incidence of pneumothoraces. Prospective randomized studies with larger numbers of well-matched patients are needed to confirm the data.

Shewanella strain isolated from black powder

Energy Technology Data Exchange (ETDEWEB)

Lutterbach, Marcia T.S.; Contador, Luciana S.; Oliveira, Ana Lucia C.; Galvao, Mariana M. [National Institute of Technology (INT), Rio de Janeiro, RJ (Brazil); Pimenta, Gutemberg S. [PETROBRAS, Rio de Janeiro, RJ (Brazil)

2009-07-01

Black powder is a term frequently used to refer to residues formed by various types of iron sulfides mixed with contaminants eventually present in the natural gas flow. According to some researchers, the occurrence of black powder in gas pipelines, besides its chemical corrosion origin, can be directly related to the sulfate-reducing bacteria (SRB) metabolism in this environment. A black powder sample was inoculated in a Post gate E medium modified with the addition of thioglycolate. The resulting positive culture was kept in the laboratory for four years until its use. A dilution technique was then performed aiming to isolate an SRB strain. The bacterial strain isolated and identified through DNA sequencing was not an SRB but rather a Shewanella sp. Compared to the sulfate-reducing bacteria group-traditionally considered the foremost responsible for microbially-influenced corrosion (MIC) - Shewanella is a facultative anaerobe and has a versatile metabolism. Shewanella is able to reduce ferric iron and sulfite, oxidize hydrogen gas, and produce hydrogen sulfide; therefore, these bacteria can be responsible for MIC and pit formation. The isolated Shewanella was used in a corrosion experiment, and the corrosion products were characterized by X-ray diffraction, identifying iron sulfides, iron oxides, and sulfur. Our results indicate that the strain isolated, S. putrefaciens, plays a key role in corrosion problems in gas pipelines. (author)

Comparison of the proteomes of three yeast wild type strains: CEN.PK2, FY1679 and W303

DEFF Research Database (Denmark)

Rogowska-Wrzesinska, A.; Mose Larsen, P.; Blomberg, A.

2001-01-01

Yeast deletion strains created during gene function analysis projects very often show drastic phenotypic differences depending on the genetic background used. These results indicate the existence of important molecular differences between the CEN.PK2, FY1679 and W303 wild type strains...

Strain gage based determination of mixed mode SIFs

Science.gov (United States)

Murthy, K. S. R. K.; Sarangi, H.; Chakraborty, D.

2018-05-01

Accurate determination of mixed mode stress intensity factors (SIFs) is essential in understanding and analysis of mixed mode fracture of engineering components. Only a few strain gage determination of mixed mode SIFs are reported in literatures and those also do not provide any prescription for radial locations of strain gages to ensure accuracy of measurement. The present investigation experimentally demonstrates the efficacy of a proposed methodology for the accurate determination of mixed mode I/II SIFs using strain gages. The proposed approach is based on the modified Dally and Berger's mixed mode technique. Using the proposed methodology appropriate gage locations (optimal locations) for a given configuration have also been suggested ensuring accurate determination of mixed mode SIFs. Experiments have been conducted by locating the gages at optimal and non-optimal locations to study the efficacy of the proposed approach. The experimental results from the present investigation show that highly accurate SIFs (0.064%) can be determined using the proposed approach if the gages are located at the suggested optimal locations. On the other hand, results also show the very high errors (212.22%) in measured SIFs possible if the gages are located at non-optimal locations. The present work thus clearly substantiates the importance of knowing the optimal locations of the strain gages apriori in accurate determination of SIFs.

Genetic background contributes to the co-morbidity of anxiety and depression with audiogenic seizure propensity and responses to fluoxetine treatment.

Science.gov (United States)

Sarkisova, Karine Yu; Fedotova, Irina B; Surina, Natalia M; Nikolaev, Georgy M; Perepelkina, Olga V; Kostina, Zoya A; Poletaeva, Inga I

2017-03-01

Anxiety and depression are the most frequent comorbidities of different types of convulsive and non-convulsive epilepsies. Increased anxiety and depression-like phenotype have been described in the genetic absence epilepsy models as well as in models of limbic epilepsy and acquired seizure models, suggesting a neurobiological connection. However, whether anxiety and/or depression are comorbid to audiogenic epilepsy remains unclear. The aim of this study was to investigate whether anxiety or depression-like behavior can be found in rat strains with different susceptibility to audiogenic seizures (AS) and whether chronic fluoxetine treatment affects this co-morbidity. Behavior in the elevated plus-maze and the forced swimming test was studied in four strains: Wistar rats non-susceptible to AS; Krushinsky-Molodkina (KM) strain, selectively bred for AS propensity from outbred Wistar rats; and a selection lines bred for maximal AS expression (strain "4") and for a lack of AS (strain "0") from KM×Wistar F2 hybrids. Effects of chronic antidepressant treatment on AS and behavior were also evaluated. Anxiety and depression levels were higher in KM rats (with AS) compared with Wistar rats (without AS), indicating the comorbidity with AS. However, in strains "4" and "0" with contrasting AS expression, but with a genetic background close to KM rats, anxiety and depression were not as divergent as in KMs versus Wistars. Fluoxetine treatment exerted an antidepressant effect in all rat strains irrespective of its effect on AS. Genetic background contributes substantively to the co-morbidity of anxiety and depression with AS propensity. Copyright © 2016 Elsevier Inc. All rights reserved.

Selective detection and quantification of modified DNA with solid-state nanopores.

Science.gov (United States)

Carlsen, Autumn T; Zahid, Osama K; Ruzicka, Jan A; Taylor, Ethan W; Hall, Adam R

2014-10-08

We demonstrate a solid-state nanopore assay for the unambiguous discrimination and quantification of modified DNA. Individual streptavidin proteins are employed as high-affinity tags for DNA containing a single biotin moiety. We establish that the rate of translocation events corresponds directly to relative concentration of protein-DNA complexes and use the selectivity of our approach to quantify modified oligonucleotides from among a background of unmodified DNA in solution.

Apolipoprotein A-IV constrains HPA and behavioral stress responsivity in a strain-dependent manner.

Science.gov (United States)

Packard, Amy E B; Zhang, Jintao; Myers, Brent; Ko, Chih-Wei; Wang, Fei; Tso, Patrick; Ulrich-Lai, Yvonne M

2017-12-01

There is a critical gap in our knowledge of the mechanisms that govern interactions between daily life experiences (e.g., stress) and metabolic diseases, despite evidence that stress can have profound effects on cardiometabolic health. Apolipoprotein A-IV (apoA-IV) is a protein found in chylomicrons (lipoprotein particles that transport lipids throughout the body) where it participates in lipid handling and the regulation of peripheral metabolism. Moreover, apoA-IV is expressed in brain regions that regulate energy balance including the arcuate nucleus. Given that both peripheral and central metabolic processes are important modulators of hypothalamic-pituitary-adrenocortical (HPA) axis activity, the present work tests the hypothesis that apoA-IV activity affects stress responses. As emerging data suggests that apoA-IV actions can vary with background strain, we also explore the strain-dependence of apoA-IV stress regulation. These studies assess HPA axis, metabolic (hyperglycemia), and anxiety-related behavioral responses to psychogenic stress in control (wildtype) and apoA-IV-deficient (KO) mice on either the C57Bl/6J (C57) or 129×1/SvJ (129) background strain. The results indicate that apoA-IV KO increases post-stress corticosterone and anxiety-related behavior specifically in the 129 strain, and increases stress-induced hyperglycemia exclusively in the C57 strain. These data support the hypothesis that apoA-IV is a novel factor that limits stress reactivity in a manner that depends on genetic background. An improved understanding of the complex relationship among lipid homeostasis, stress sensitivity, and genetics is needed to optimize the development of personalized treatments for stress- and metabolism-related diseases. Copyright © 2017 Elsevier Ltd. All rights reserved.

Methodology optimization and diversification for the investigation of virulence potential in Haemophilus influenzae clinical strains.

Science.gov (United States)

Giucă, Mihaela Cristina; Străuţ, Monica; Surdeanu, Maria; Nica, Maria; Ungureanu, Vasilica; Mihăescu, Grigore

2011-01-01

Ten Haemophilus influenzae strains were isolated from patients aged between 1.6 - 24 years, with various diagnoses (acute meningitis, acute upper respiratory infection, otitis media and acute sinusitis). Identification was based on phenotypic and molecular characteristics; antibiotic susceptibility testing was performed by diffusion method according to CLSI standards 2011 for seven antibiotics. The results of molecular testing showed that all the studied strains produced an amplicon of 1000 bp with ompP2 primers indicating that all strains were H. influenzae. For six strains, the PCR amplicon obtained with bexA specific primers, proving that the strains were capsulated. The results of phenotypic testing showed that four strains were ampicillin nonsusceptible and (beta-lactamase-positive. The virulence potential of H. influenzae clinical strains was investigated by phenotypic methods, including the assessment of the soluble virulence factors on specific media containing the biochemical substratum for the investigated enzymatic factor, as well as the adherence and invasion capacity to HeLa cells monolayer using Cravioto modified method. The studied strains exhibited mainly a diffuse adherence pattern and different adherence indexes. Interestingly, two strains isolated from the same pacient (blood and CSF) showed a different degree of invasiveness, the strain isolated from blood being 20 times more invasive than the one isolated from CSF.

Numerical analysis of modified Central Solenoid insert design

Energy Technology Data Exchange (ETDEWEB)

Khodak, Andrei, E-mail: akhodak@pppl.gov [Princeton Plasma Physics Laboratory, Princeton, NJ (United States); Martovetsky, Nicolai; Smirnov, Aleksandre [Oak Ridge National Laboratory, Oak Ridge, TN (United States); Titus, Peter [Princeton Plasma Physics Laboratory, Princeton, NJ (United States)

2015-10-15

Highlights: • Modified design of coil for testing ITER superconducting cable is presented. • Numerical analysis allowed design verification. • Three-dimensional current sharing temperature distributions are obtained from the results. - Abstract: The United States ITER Project Office (USIPO) is responsible for fabrication of the Central Solenoid (CS) for ITER project. The ITER machine is currently under construction by seven parties in Cadarache, France. The CS Insert (CSI) project should provide a verification of the conductor performance in relevant conditions of temperature, field, currents and mechanical strain. The US IPO designed the CSI that will be tested at the Central Solenoid Model Coil (CSMC) Test Facility at JAEA, Naka. To validate the modified design three-dimensional numerical simulations were performed using coupled solver for simultaneous structural, thermal and electromagnetic analysis. Thermal and electromagnetic simulations supported structural calculations providing necessary loads and strains. According to current analysis design of the modified coil satisfies ITER magnet structural design criteria for the following conditions: (1) room temperature, no current, (2) temperature 4 K, no current, (3) temperature 4 K, current 60 kA direct charge, and (4) temperature 4 K, current 60 kA reverse charge. Fatigue life assessment analysis is performed for the alternating conditions of: temperature 4 K, no current, and temperature 4 K, current 45 kA direct charge. Results of fatigue analysis show that parts of the coil assembly can be qualified for up to 1 million cycles. Distributions of the Current Sharing Temperature (TCS) in the superconductor were obtained from numerical results using parameterization of the critical surface in the form similar to that proposed for ITER. Special ADPL scripts were developed for ANSYS allowing one-dimensional representation of TCS along the cable, as well as three-dimensional fields of TCS in superconductor

Effect of strain rate on the tensile properties of α- and delta-stabilized plutonium

International Nuclear Information System (INIS)

Hecker, S.S.; Morgan, J.R.

1975-01-01

The tensile properties of unalloyed α-Pu and 3.4 at. percent Ga-stabilized delta-Pu were determined at strain rates from 10 -5 to 100/s. Tests at strain rates less than 10 -2 /s were conducted on an Instron Testing Machine; those at strain rates between 10 -2 and 3/s on a closed-loop electrohydraulic MTS system; and those at strain rates greater than 3/s on a specially modified Charpy Impact Tester. Three lots of delta-Pu, one rolled and annealed and the other two cast and homogenized, were tested. The 0.2 percent yield strengths and ultimate tensile strengths increased by an average of 5.2 and 6.0 MPa per factor of 10 increase in strain rate. This increase was achieved without penalty in tensile ductility as measured by total elongation to fracture and by reduction in area. The isostatically pressed α-Pu specimens also showed a large increase in fracture stress with strain rate (34.3 MPa per factor to 10 increase in strain rate). The fracture was macroscopically brittle (plastic strains less than 0.3 percent) although we observed extensive evidence of microscopic flow in the ductile dimple-type appearance of the fracture surfaces. The strain to fracture appeared to exhibit a minimum at a strain rate of 10 -2 /s. (U.S.)

Optimizing the top quark signal to background ratio at hadron colliders

International Nuclear Information System (INIS)

Field, R.D.; Kanev, Y.; Tayebnejad, M.

1996-01-01

We investigate the event signature of the ell νb bar bq bar q decay mode of top-pair production in proton-antiproton collisions at 1.8 TeV. Neural networks and Fisher discriminates are used in conjunction with modified Fox-Wolfram open-quotes shapeclose quotes variables to help distinguish the top-pair signal from the W + jets and b bar b+jets background. Instead of requiring at least four jets in the event, we find that it is faster and better to simply cut on the number of calorimeter cells with transverse energy greater than some minimum. By combining these cell cuts with the event shape information, we are able to obtain a signal to background ratio of around 9 while keeping 30% of the signal. This corresponds to a signal to background enhancement of around 370

Borehole strain observations of very low frequency earthquakes

Science.gov (United States)

Hawthorne, J. C.; Ghosh, A.; Hutchinson, A. A.

2016-12-01

We examine the signals of very low frequency earthquakes (VLFEs) in PBO borehole strain data in central Cascadia. These MW 3.3 - 4.1 earthquakes are best observed in seismograms at periods of 20 to 50 seconds. We look for the strain they produce on timescales from about 1 to 30 minutes. First, we stack the strain produced by 13 VLFEs identified by a grid search moment tensor inversion algorithm by Ghosh et. al. (2015) and Hutchinson and Ghosh (2016), as well as several thousand VLFEs detected through template matching these events. The VLFEs are located beneath southernmost Vancouver Island and the eastern Olympic Peninsula, and are best recorded at co-located stations B005 and B007. However, even at these stations, the signal to noise in the stack is often low, and the records are difficult to interpret. Therefore we also combine data from multiple stations and VLFE locations, and simply look for increases in the strain rate at the VLFE times, as increases in strain rate would suggest an increase in the moment rate. We compare the background strain rate in the 12 hours centered on the VLFEs with the strain rate in the 10 minutes centered on the VLFEs. The 10-minute duration is chosen as a compromise that averages out some instrumental noise without introducing too much longer-period random walk noise. Our results suggest a factor of 2 increase in strain rate--and thus moment rate--during the 10-minute VLFE intervals. The increase gives an average VLFE magnitude around M 3.5, within the range of magnitudes obtained with seismology. Further analyses are currently being carried out to better understand the evolution of moment release before, during, and after the VLFEs.

Ring strain and total syntheses of modified macrocycles of the isoplagiochin type

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Andreas Speicher

2009-12-01

Full Text Available Macrocycles of the bisbibenzyl-type are natural products that are found exclusively in bryophytes (liverworts. The molecular framework of the subtype “isoplagiochin” is of substantial structural interest because of the chirality of the entire molecule, which arises from two biaryl axes in combination with two helical two-carbon units in a cyclic arrangement. From a structural as well as a synthetic point of view we report on the total synthesis of compounds which possess more rigid two-carbon biaryl bridges like stilbene (E or Z or even tolane moieties which were introduced starting with a Sonogashira protocol. The McMurry method proved to be a powerful tool for the cyclization to these considerably ring-strained macrocycles.

Comparison of SHF and SSF processes from steam-exploded wheat straw for ethanol production by xylose-fermenting and robust glucose-fermenting Saccharomyces cerevisiae strains

DEFF Research Database (Denmark)

Tomas Pejo, Elia; Oliva, Jose M.; Ballesteros, Mercedes

2008-01-01

In this study, bioethanol production from steam-exploded wheat straw using different process configurations was evaluated using two Saccharomyces cerevisiae strains, F12 and Red Star. The strain F12 has been engineerically modified to allow xylose consumption as cereal straw contain considerable ...

Background noise measurements from jet exit vanes designed to reduced flow pulsations in an open-jet wind tunnel

Science.gov (United States)

Hoad, D. R.; Martin, R. M.

1985-01-01

Many open jet wind tunnels experience pulsations of the flow which are typically characterized by periodic low frequency velocity and pressure variations. One method of reducing these fluctuations is to install vanes around the perimeter of the jet exit to protrude into the flow. Although these vanes were shown to be effective in reducing the fluctuation content, they can also increase the test section background noise level. The results of an experimental acoustic program in the Langley 4- by 7-Meter Tunnel is presented which evaluates the effect on tunnel background noise of such modifications to the jet exit nozzle. Noise levels for the baseline tunnel configuration are compared with those for three jet exit nozzle modifications, including an enhanced noise reduction configuration that minimizes the effect of the vanes on the background noise. Although the noise levels for this modified vane configuration were comparable to baseline tunnel background noise levels in this facility, installation of these modified vanes in an acoustic tunnel may be of concern because the noise levels for the vanes could be well above background noise levels in a quiet facility.

Individual or synchronous biodegradation of di-n-butyl phthalate and phenol by Rhodococcus ruber strain DP-2

Energy Technology Data Exchange (ETDEWEB)

He, Zhixing; Niu, Chengzhen; Lu, Zhenmei, E-mail: lzhenmei@zju.edu.cn

2014-05-01

Highlights: • A Rhodococcus ruber strain degraded DBP and phenol. • Degradation kinetics of DBP or phenol fit modified first-order models. • Degradation interaction between DBP and phenol was studied by strain DP-2. • The degradation genes transcriptional were quantified by RT-qPCR. - Abstract: The bacterial strain DP-2, identified as Rhodococcus ruber, is able to effectively degrade di-n-butyl phthalate (DBP) and phenol. Degradation kinetics of DBP and phenol at different initial concentrations revealed DBP and phenol degradation to fit modified first-order models. The half-life of DBP degradation ranged from 15.81 to 27.75 h and phenol degradation from 14.52 to 45.52 h under the initial concentrations of 600–1200 mg/L. When strain DP-2 was cultured with a mixture of DBP (800 mg/L) and phenol (700 mg/L), DBP degradation rate was found to be only slightly influenced; however, phthalic acid (PA) accumulated, and phenol degradation was clearly inhibited during synchronous degradation. Transcriptional levels of degradation genes, phenol hydroxylase (pheu) and phthalate 3,4-dioxygenase (pht), decreased significantly more during synchronous degradation than during individual degradation. Quantitative estimation of individual or synchronous degradation kinetics is essential to manage mixed hazardous compounds through biodegradation in industrial waste disposal.

Nonderivative Modified Gravity: a Classification

CERN Document Server

Comelli, Denis; Pilo, Luigi

2014-01-01

We analyze the theories of gravity modified by a generic nonderivative potential built from the metric, under the minimal requirement of unbroken spatial rotations. Using the canonical analysis, we classify the potentials $V$ according to the number of degrees of freedom (DoF) that propagate at the nonperturbative level. We then compare the nonperturbative results with the perturbative DoF propagating around Minkowski and FRW backgrounds. A generic $V$ implies 6 propagating DoF at the non-perturbative level, with a ghost on Minkowski background. There exist potentials which propagate 5 DoF, as already studied in previous works. Here, no $V$ with unbroken rotational invariance admitting 4 DoF is found. Theories with 3 DoF turn out to be strongly coupled on Minkowski background. Finally, potentials with only the 2 DoF of a massive graviton exist. Their effect on cosmology is simply equivalent to a cosmological constant. Potentials with 2 or 5 DoF and explicit time dependence appear to be a further viable possib...

Evaluation of right heart function in a rat model using modified echocardiographic views.

Science.gov (United States)

Bernardo, Ivan; Wong, James; Wlodek, Mary E; Vlahos, Ross; Soeding, Paul

2017-01-01

Echocardiography plays a major role in assessing cardiac function in animal models. We investigated use of a modified parasternal mid right-ventricular (MRV) and right ventricle (RV) outflow (RVOT) view, in assessing RV size and function, and the suitability of advanced 2D-strain analysis. 15 WKY rats were examined using transthoracic echocardiography. The left heart was assessed using standard short and long axis views. For the right ventricle a MRV and RVOT view were used to measure RV chamber and free wall area. 2D-strain analysis was applied to both ventricles using off-line analysis. RV chamber volume was determined by injection of 2% agarose gel, and RV free wall dissected and weighed. Echocardiography measurement was correlated with necropsy findings. The RV mid-ventricular dimension (R1) was 0.42±0.07cm and the right ventricular outflow tract dimension (R2) was 0.34±0.06cm, chamber end-diastolic area measurements were 0.38±0.09cm2 and 0.29±0.08cm2 for MRV and RVOT views respectively. RVOT and MRV chamber area correlated with gel mass. Doppler RV stroke volume was 0.32±0.08ml, cardiac output (CO) 110±27 ml.min-1 and RV free wall contractility assessed using 2D-strain analysis was demonstrated. We have shown that modified MRV and RVOT views can provide detailed assessment of the RV in rodents, with 2D-strain analysis of the RV free wall potentially feasible.

Evaluation of Antimicrobial Activity of Bacillus Strains Isolated from Various Resources

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Mohsen Golnari Maranni

2017-02-01

Full Text Available Abstract Background: Prevalence extension of antibiotic resistant bacteria has raised concerns about control of infections especially nosocomial infections. Many attempts have been done to replace antibiotics or limit their use. The use of antimicrobial agents produced by bacteria as antibiotic replacement has been promising in recent years. The goal of this study was to isolate Bacillus strains and evaluate their antimicrobial activity against some standard pathogens and clinical antibiotic resistant strains. Materials and Methods: In the present study, Bacillus strains were isolated from various resources and identified by 16S rDNA PCR method. Then, the phylogenetic tree of the isolates was constructed and antimicrobial activity of the isolates was investigated against some standard pathogens and clinical antibiotic resistant strains using spotting and well diffusion methods. Results: Eight Bacillus strains were isolated from 15 different samples. Based on the molecular identification, the isolates were identified as B.pumilus, B.coagulans, B.licheniformis, B.endophitycus and B.amiloliquefaciens. The results showed that isolates have antimicrobial activity against meticilin-resistant Staphylococcus aureus, vancomycin resistant enterococci, Klebsiella, Acinetobacter, Salmonella, Shigella, Listeria, Streptococcus and Escherichia coli. Conclusion: In this study, isolated Bacillus strains produced antimicrobial agents against pathogens and antibiotic resistant strains and inhibited their growth.

Chemicalome and metabolome profiling of polymethoxylated flavonoids in Citri Reticulatae Pericarpium based on an integrated strategy combining background subtraction and modified mass defect filter in a Microsoft Excel Platform.

Science.gov (United States)

Zeng, Su-Ling; Duan, Li; Chen, Bai-Zhong; Li, Ping; Liu, E-Hu

2017-07-28

Detection of metabolites in complex biological matrixes is a great challenge because of the background noise and endogenous components. Herein, we proposed an integrated strategy that combined background subtraction program and modified mass defect filter (MMDF) data mining in a Microsoft Excel platform for chemicalome and metabolome profiling of the polymethoxylated flavonoids (PMFs) in Citri Reticulatae Pericarpium (CRP). The exogenously-sourced ions were firstly filtered out by the developed Visual Basic for Applications (VBA) program incorporated in the Microsoft Office. The novel MMDF strategy was proposed for detecting both target and untarget constituents and metabolites based on narrow, well-defined mass defect ranges. The approach was validated to be powerful, and potentially useful for the metabolite identification of both single compound and homologous compound mixture. We successfully identified 30 and 31 metabolites from rat biosamples after oral administration of nobiletin and tangeretin, respectively. A total of 56 PMFs compounds were chemically characterized and 125 metabolites were captured. This work demonstrated the feasibility of the integrated approach for reliable characterization of the constituents and metabolites in herbal medicines. Copyright © 2017 Elsevier B.V. All rights reserved.

Controlling residual dipolar couplings in high-resolution NMR of proteins by strain induced alignment in a gel

International Nuclear Information System (INIS)

Ishii, Yoshitaka; Markus, Michelle A.; Tycko, Robert

2001-01-01

Water-soluble biological macromolecules can be weakly aligned by dissolution in a strained, hydrated gel such as cross-linked polyacrylamide, an effect termed 'strain-induced alignment in a gel' (SAG). SAG induces nonzero nuclear magnetic dipole-dipole couplings that can be measured in high-resolution NMR spectra and used as structural constraints. The dependence of experimental 15 N- 1 H dipolar couplings extracted from two-dimensional heteronuclear single quantum coherence (HSQC) spectra on several properties of compressed polyacrylamide, including the extent of compression, the polyacrylamide concentration, and the cross-link density, is reported for the B1 immunoglobulin binding domain of streptococcal protein G (protein G/B1, 57 residues). It is shown that the magnitude of macromolecular alignment can be widely varied by adjusting these properties, although the orientation and asymmetry of the alignment tensor are not affected significantly. The dependence of the 15 N relaxation times T 1 and T 2 of protein G/B1 on polyacrylamide concentration are also reported. In addition, the results of 15 N relaxation and HSQC experiments on the RNA binding domain of prokaryotic protein S4 from Bacillus stearothermophilus (S4 Δ41, residues 43-200) in a compressed polyacrylamide gel are presented. These results demonstrate the applicability of SAG to proteins of higher molecular weight and greater complexity. A modified in-phase/anti-phase (IPAP) HSQC technique is described that suppresses natural-abundance 15 N background signals from amide groups in polyacrylamide, resulting in cleaner HSQC spectra in SAG experiments. The mechanism of protein alignment in strained polyacrylamide gels is contrasted with that in liquid crystalline media

Gentamicin-Containing Peptone-Yeast Extract Medium for Cocultivation of Hartmannella vermiformis ATCC 50256 and Virulent Strains of Legionella pneumophila.

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Wadowsky, R M; Wang, L; Laus, S; Dowling, J N; Kuchta, J M; States, S J; Yee, R B

1995-12-01

We evaluated the use of peptone-yeast extract (PY) medium, different strains of Hartmannella vermiformis, and gentamicin in a coculture system to improve the discrimination of virulent and avirulent strains of Legionella pneumophila. H. vermiformis ATCC 50256 was unique among four strains of H. vermiformis, in that it multiplied equally well in Medium 1034 and PY medium (Medium 1034 without fetal calf serum, folic acid, hemin, and yeast nucleic acid and with a 50% reduction of peptone). However, both a virulent strain of L. pneumophila and its avirulent derivative strain multiplied in cocultures when PY medium was used. The multiplication of this avirulent strain was greatly reduced by incorporating gentamicin (1 (mu)g/ml) into the cocultivation system. Five virulent-avirulent sets of L. pneumophila strains were then tested for multiplication in cocultures with H. vermiformis ATCC 50256 and the gentamicin-containing PY medium. Only the virulent strains multiplied. The modified cocultivation system can discriminate between virulent and avirulent strains of L. pneumophila.

Absorbing systematic effects to obtain a better background model in a search for new physics

International Nuclear Information System (INIS)

Caron, S; Horner, S; Sundermann, J E; Cowan, G; Gross, E

2009-01-01

This paper presents a novel approach to estimate the Standard Model backgrounds based on modifying Monte Carlo predictions within their systematic uncertainties. The improved background model is obtained by altering the original predictions with successively more complex correction functions in signal-free control selections. Statistical tests indicate when sufficient compatibility with data is reached. In this way, systematic effects are absorbed into the new background model. The same correction is then applied on the Monte Carlo prediction in the signal region. Comparing this method to other background estimation techniques shows improvements with respect to statistical and systematic uncertainties. The proposed method can also be applied in other fields beyond high energy physics.

Enhancing adhesion of yeast brewery strains to chamotte carriers through aminosilane surface modification.

Science.gov (United States)

Berlowska, Joanna; Kregiel, Dorota; Ambroziak, Wojciech

2013-07-01

The adhesion of cells to solid supports is described as surface-dependent, being largely determined by the properties of the surface. In this study, ceramic surfaces modified using different organosilanes were tested for proadhesive properties using industrial brewery yeast strains in different physiological states. Eight brewing strains were tested: bottom-fermenting Saccharomyces pastorianus and top-fermenting Saccharomyces cerevisiae. To determine adhesion efficiency light microscopy, scanning electron microscopy and the fluorymetric method were used. Modification of chamotte carriers by 3-(3-anino-2-hydroxy-1-propoxy) propyldimethoxysilane and 3-(N, N-dimethyl-N-2-hydroxyethyl) ammonium propyldimethoxysilane groups increased their biomass load significantly.

A novel compliance measurement in radial arteries using strain-gauge plethysmography

International Nuclear Information System (INIS)

Liu, Shing-Hong; Tyan, Chu-Chang; Chang, Kang-Ming

2009-01-01

We propose a novel method for assessing the compliance of the radial artery by using a two-axis mechanism and a standard positioning procedure for detecting the optimal measuring site. A modified sensor was designed to simultaneously measure the arterial diameter change waveform (ADCW) and pressure pulse waveform with a strain gauge and piezoresistor. In the x-axis scanning, the sensor could be placed close to the middle of the radial artery when the ADCW reached the maximum amplitude. In the z-axis scanning, the contact pressure was continuously increased for data measurement. Upon the deformation of the strain gauge following the change in the vascular cross-section, the ADCW was transferred to the change of the vascular radius. The loaded strain compliance of the radial artery (C strain ) can be determined by dividing the dynamic changed radius by the pulse pressure. Twenty-three untreated, mild or moderate hypertensive patients aged 29–85 were compared with 14 normotensive patients aged 25–62. The maximum strain compliance between the two groups was significantly different (p < 0.005). Of the hypertensive patients, 14 were at risk of developing hyperlipidemia. There was a significant difference between this and the normotension group (p < 0.005)

A novel compliance measurement in radial arteries using strain-gauge plethysmography.

Science.gov (United States)

Liu, Shing-Hong; Tyan, Chu-Chang; Chang, Kang-Ming

2009-09-01

We propose a novel method for assessing the compliance of the radial artery by using a two-axis mechanism and a standard positioning procedure for detecting the optimal measuring site. A modified sensor was designed to simultaneously measure the arterial diameter change waveform (ADCW) and pressure pulse waveform with a strain gauge and piezoresistor. In the x-axis scanning, the sensor could be placed close to the middle of the radial artery when the ADCW reached the maximum amplitude. In the Z-axis scanning, the contact pressure was continuously increased for data measurement. Upon the deformation of the strain gauge following the change in the vascular cross-section, the ADCW was transferred to the change of the vascular radius. The loaded strain compliance of the radial artery (C(strain)) can be determined by dividing the dynamic changed radius by the pulse pressure. Twenty-three untreated, mild or moderate hypertensive patients aged 29-85 were compared with 14 normotensive patients aged 25-62. The maximum strain compliance between the two groups was significantly different (p < 0.005). Of the hypertensive patients, 14 were at risk of developing hyperlipidemia. There was a significant difference between this and the normotension group (p < 0.005).

Strain- and sex-dependent circadian changes in abcc2 transporter expression: implications for irinotecan chronotolerance in mouse ileum.

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Alper Okyar

Full Text Available ATP-binding cassette transporter abcc2 is involved in the cellular efflux of irinotecan. The drug is toxic for mouse ileum, where abcc2 is highly expressed. Here, we investigate whether circadian changes in local abcc2 expression participate in the circadian rhythm of irinotecan toxicity for ileum mucosa, and further assess whether genetic background or sex modify this relation.Ileum mucosa was obtained every 3-4 h for 24 h in male and female B6D2F(1 and B6CBAF(1 mice synchronized with light from Zeitgeber Time (ZT0 to ZT12 alternating with 12 h of darkness. Irinotecan (50 mg/kg i.v. daily for 4 days was administered at the sex- and strain-specific times corresponding to least (ZT11-15 or largest drug-induced body weight loss (ZT23-03-07. Abcc2 expression was determined with qRT-PCR for mRNA and with immunohistochemistry and confocal microscopy for protein. Histopathologic lesions were graded in ileum tissues obtained 2, 4 or 6 days after treatment. Two- to six-fold circadian changes were demonstrated for mRNA and protein mean expressions of abcc2 in mouse ileum (p<0.05. ZT12 corresponded to high mRNA and protein expressions, with circadian waveforms differing according to genetic background and sex. The proportion of mice spared from ileum lesions varied three-fold according to irinotecan timing, with best tolerability at ZT11-15 (p = 0.00003. Irinotecan was also best tolerated in males (p = 0.05 and in B6CBAF(1 (p = 0.0006.Strain- and sex-dependent circadian patterns in abcc2 expressions displayed robust relations with the chronotolerance of ileum mucosa for irinotecan. This finding has strong potential implications for improving the intestinal tolerability of anticancer drugs through circadian delivery.

Search for a stochastic background of 100-MHz gravitational waves with laser interferometers.

Science.gov (United States)

Akutsu, Tomotada; Kawamura, Seiji; Nishizawa, Atsushi; Arai, Koji; Yamamoto, Kazuhiro; Tatsumi, Daisuke; Nagano, Shigeo; Nishida, Erina; Chiba, Takeshi; Takahashi, Ryuichi; Sugiyama, Naoshi; Fukushima, Mitsuhiro; Yamazaki, Toshitaka; Fujimoto, Masa-Katsu

2008-09-05

This Letter reports the results of a search for a stochastic background of gravitational waves (GW) at 100 MHz by laser interferometry. We have developed a GW detector, which is a pair of 75-cm baseline synchronous recycling (resonant recycling) interferometers. Each interferometer has a strain sensitivity of approximately 10;{-16} Hz;{-1/2} at 100 MHz. By cross-correlating the outputs of the two interferometers within 1000 seconds, we found h{100};{2}Omega_{gw}<6 x 10;{25} to be an upper limit on the energy density spectrum of the GW background in a 2-kHz bandwidth around 100 MHz, where a flat spectrum is assumed.

Context and strain-dependent behavioral response to stress

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Baum Amber E

2008-06-01

Full Text Available Abstract Background This study posed the question whether strain differences in stress-reactivity lead to differential behavioral responses in two different tests of anxiety. Strain differences in anxiety-measures are known, but strain differences in the behavioral responses to acute prior stress are not well characterized. Methods We studied male Fisher 344 (F344 and Wistar Kyoto (WKY rats basally and immediately after one hour restraint stress. To distinguish between the effects of novelty and prior stress, we also investigated behavior after repeated exposure to the test chamber. Two behavioral tests were explored; the elevated plus maze (EPM and the open field (OFT, both of which are thought to measure activity, exploration and anxiety-like behaviors. Additionally, rearing, a voluntary behavior, and grooming, a relatively automatic, stress-responsive stereotyped behavior were measured in both tests. Results Prior exposure to the test environment increased anxiety-related measures regardless of prior stress, reflecting context-dependent learning process in both tests and strains. Activity decreased in response to repeated testing in both tests and both strains, but prior stress decreased activity only in the OFT which was reversed by repeated testing. Prior stress decreased anxiety-related measures in the EPM, only in F344s, while in the OFT, stress led to increased freezing mainly in WKYs. Conclusion Data suggest that differences in stressfulness of these tests predict the behavior of the two strains of animals according to their stress-reactivity and coping style, but that repeated testing can overcome some of these differences.

Antibodies with higher bactericidal activity induced by a Neisseria gonorrhoeae Rmp deletion mutant strain.

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Guocai Li

Full Text Available Neisseria gonorrhoeae (N. gonorrhoeae outer membrane protein reduction modifiable protein (Rmp has strong immunogenicity. However, anti-Rmp antibodies block rather than preserve the antibacterial effects of protective antibodies, which hampers the development of vaccines for gonococcal infections. We herein constructed an Rmp deletion mutant strain of N. gonorrhoeae by gene homologous recombination. The 261-460 nucleotide residues of Rmp gene amplified from N. gonorrhoeae WHO-A strain were replaced with a kanamycin-resistant Kan gene amplified from pET-28a. The resultant hybridized DNA was transformed into N. gonorrhoeae WHO-A strain. PCR was used to screen the colonies in which wild-type Rmp gene was replaced with a mutant gene fragment. Western blotting revealed that the Rmp deletion mutant strain did not express Rmp protein. Rmp deletion did not alter the morphological and Gram staining properties of the mutant strain that grew slightly more slowly than the wild-type one. Rmp gene mutated stably throughout 25 generations of passage. Antibody-mediated complement-dependent cytotoxicity assay indicated that the antibodies induced by the mutant strain had evidently higher bactericidal activities than those induced by the wild-type strain. Further modification of the Rmp deletion mutant strain is still required in the development of novel live attenuated vaccines for gonorrhea by Opa genes deletion or screening of phenotypic variant strains that do not express Opa proteins.

Genetic and phenotypic diversity of naturally isolated wild strains of Aspergillus niger with hyper glucose oxidase production

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MAHMOUD EL-HARIRI

2015-12-01

Full Text Available Glucose oxidase (GOx is the basic stone for many of biological industry worldwide. The improvement of GOx production basically depends on selection of hyper producer strain of Aspergillus niger. Selective isolation and screening for natural hyper producer strains of A. niger and sequence analysis of the GOD gene, which is responsible for production of the enzyme, are very effective approaches to investigate the naturally modified strains of A. niger with hyper productive capacity of GOx enzyme. The aims of the current study were selective isolation of naturally hyper GOx producing strains of A. niger and evaluation of their GOx activities under optimized parameters in the laboratory. Five wild Egyptian isolates of A. niger were screened for GOx and catalase activity using two types of modified basal liquid media. The GOx activity was evaluated by high throughout liquid phase system. The isolates showed a variable activity for GOx production ranged from 0 to 28.7 U.ml-1. One isolate coded Strain 7 was negative GOx producer on Vogel's broth medium in comparison to other isolates, while its GOx activity on Cazpek Dox was considered as positive (7.28 U.ml-1. It was concluded that GOx production is affected by three controllable factors – the basal media components, time of incubation, and the strain with its adaption to the media components‎. Also, the catalase activity was tested and it was produced with a different degree of variability, which may be reflected on GOx stability. GOD genes of these wild variant of A. niger were cloned and sequenced to determine intraspecies diversity of GOD between the wild variants. The comparison of isolated wild variants to other reference hyper GOx producer strains of A. niger was performed to determine if the GOD sequence analysis of these strains can be distinguished based on their GOx activity. This is the first report for isolation and detection of naturally A. niger hyper GOx-producer strains with

EVALUATION OF DISTAL UPPER EXTREMITY (DUE MUSCULOSKELETAL DISORDERS BY STRAIN INDEX (SI IN AN IRONWORK INDUSTRY

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Seyed-Ali Moussavi-Najarkola

2008-04-01

Full Text Available Background and aims:Work-related musculoskeletal disorders (WMSDS is one of the mostimportant problems in working populations of Iranian industries; so, in order to evaluate theintegrated roles and effects of various ergonomic risk factors inducing such disorders, the StrainIndex (SI methods was used.Methods: This was a cross-sectional study conducted on 448 male subjects including 63controls working in administrative jobs and 385 cases working in lathing, welding, melting andfoundry jobs using integrated procedure which includes observations, interview, NordicMusculoskeletal Questionnaire (NMQ methods and SI model. All workers were questioned.Data were analyzed using SPSS software v. 11 and Excel package.Results: The most prevalent MSDs in upper limbs were found in melting lathing, foundry andwelding respectively. There was a significant relationship between age and job groups (c2=7.33;df=16; p<0.001. One-way analysis of variance showed a significant differences among means ofcalculated Strain Indices of administrative (1.06, lathing (6.52, welding (3.68, melting (7.79and foundry (6.33 jobs (F=5.92; df=16; p=0.005. Also it was revealed that melting job wasattributed as "hazardous job" (4 risk level, lathing and foundry jobs were referred to "moderaterisk level" (3 risk level, welding job was allocated as "uncertain risk level" (2 risk level, andadministrative job was attributed as "safe risk level" (1 risk level. Moreover, there was asignificant relationship between DUE and job groups (c2=11.92; df=12; p=0.004.The paired ttestshowed significant difference with direct and relatively complete correlation between meansof Strain Indices in right (6.53 and left (4.29 hands (r=0.69; t=3.15; p<0.001.Conclusion: The Strain Index (SI model can be referred as an efficient and applicable methodfor the assessment of ergonomics risk factors inducing upper extremity musculoskeletal disorders(UEMSDs, classifying jobs, correcting and modifying work situations

Processing and Characterization of a Novel Distributed Strain Sensor Using Carbon Nanotube-Based Nonwoven Composites

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Hongbo Dai

2015-07-01

Full Text Available This paper describes the development of an innovative carbon nanotube-based non-woven composite sensor that can be tailored for strain sensing properties and potentially offers a reliable and cost-effective sensing option for structural health monitoring (SHM. This novel strain sensor is fabricated using a readily scalable process of coating Carbon nanotubes (CNT onto a nonwoven carrier fabric to form an electrically-isotropic conductive network. Epoxy is then infused into the CNT-modified fabric to form a free-standing nanocomposite strain sensor. By measuring the changes in the electrical properties of the sensing composite the deformation can be measured in real-time. The sensors are repeatable and linear up to 0.4% strain. Highest elastic strain gage factors of 1.9 and 4.0 have been achieved in the longitudinal and transverse direction, respectively. Although the longitudinal gage factor of the newly formed nanocomposite sensor is close to some metallic foil strain gages, the proposed sensing methodology offers spatial coverage, manufacturing customizability, distributed sensing capability as well as transverse sensitivity.

Modified GrabCut for human face segmentation

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Dina Khattab

2014-12-01

Full Text Available GrabCut is a segmentation technique for 2D still color images, which is mainly based on an iterative energy minimization. The energy function of the GrabCut optimization algorithm is based mainly on a probabilistic model for pixel color distribution. Therefore, GrabCut may introduce unacceptable results in the cases of low contrast between foreground and background colors. In this manner, this paper presents a modified GrabCut technique for the segmentation of human faces from images of full humans. The modified technique introduces a new face location model for the energy minimization function of the GrabCut, in addition to the existing color one. This location model considers the distance distribution of the pixels from the silhouette boundary of a fitted head, of a 3D morphable model, to the image. The experimental results of the modified GrabCut have demonstrated better segmentation robustness and accuracy compared to the original GrabCut for human face segmentation.

Comparison of the Amount of Fluoride Release from Nanofilled Resin Modified Glass Ionomer Conventional and Resin Modified Glass Ionomer Cements

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Sumitha Upadhyay

2013-01-01

Full Text Available Objective: To investigate and compare the amount of fluoride release of conventional, resin modified and nanofilled resin modified glass ionomer cements.Materials and Methods: Tablets of glass-ionomer cements were immersed in deionized water and incubated at 37◦C. After 1, 2, 7, 15 and 30 days, fluoride ion was measured under normal atmospheric conditions by fluoride ion selective electrode. Buffer (TISAB II was used to decomplex the fluoride ion and to provide a constant background ionic strength and to maintain the pH of water between 5.0 and 5.5 as the fluoride electrode is sensitive to changes in pH. Statistical evaluation was carried out by one way ANOVA (Analysis of Variance using SPSS 11.0. The significance level was set at p< 0.05.Results: The release of fluoride was highest on day 1 and there was a sudden fall on day 2 in all three groups. Initially fluoride release from conven-tional glass-ionomer cement was highest compared to the other two glass-ionomer cements, but the amount drastically reduced over the period. Although the amount of fluoride release was less than both the resin modified and nanofilled resin modified glass-ionomer cement, the release was sustained consistently for 30 daysConclusion: The cumulative fluoride release of nanofilled resin modified glass ionomer cement was very less compared to the conventional and resin modified glass ionomer cements and Nanofilled resin modified glass ionomer cement released less but steady fluoride as compared to other resin modified glass ionomer cements.

Comparison of palladium chemical modifiers for the determination of selenium in plasma by Zeeman-effect background corrected electrothermal atomic absorption spectrometry

DEFF Research Database (Denmark)

Gammelgaard, Bente; Jons, O.

1997-01-01

, It was not possible to stabilize trimethylselenonium to the same extent with this modifier, Peak shapes and appearance times of the atomization signals were equal for the four selenium species with this modifier, The addition of 20 mu g of palladium was used for the analysis of the serum reference material Seronorm...

VUV treatment combined with mechanical strain of stretchable polymer foils resulting in cell alignment

Energy Technology Data Exchange (ETDEWEB)

Barb, R.-A. [Institute of Applied Physics, Johannes Kepler University Linz (Austria); Magnus, B. [Innovacell Biotechnologie AG, Innsbruck (Austria); Innerbichler, S. [Innerbichler GmbH, Breitenbach am Inn (Austria); Greunz, T. [CDL-MS-MACH, Johannes Kepler University Linz (Austria); Wiesbauer, M. [Institute of Applied Physics, Johannes Kepler University Linz (Austria); Marksteiner, R. [Innovacell Biotechnologie AG, Innsbruck (Austria); Stifter, D. [CDL-MS-MACH, Johannes Kepler University Linz (Austria); Heitz, J., E-mail: johannes.heitz@jku.at [Institute of Applied Physics, Johannes Kepler University Linz (Austria)

2015-01-15

Highlights: • Elastic polyurethane (PU) foils were exposed to the vacuum-UV in reactive atmosphere. • The photomodification resulted in improved cytocompatibilty. • Parallel microgrooves formed on the irradiated PU surfaces after strong elongation. • Cells seeded onto microgrooves aligned their shapes in the direction of the grooves. • Elongation occurred also for cells on PU subjected to cyclic mechanical stretching. - Abstract: Cell-alignment along a defined direction can have a direct effect on the cell functionality and differentiation. Oriented micro- or nanotopographic structures on cell culture substrates can induce cell-alignment. Surface chemistry, wettability, and stiffness of the substrate are also important material features as they strongly influence the cell–substrate interactions. For improved bio-compatibility, highly elastic polyurethane (PU) foils were exposed to the vacuum-UV (VUV) light of a Xe{sub 2}{sup *} excimer lamp at 172 nm in a nitrogen containing atmosphere (N{sub 2} or NH{sub 3}). The irradiation resulted in a change in the chemical surface composition. Additionally, the formation of regular parallel microgrooves was observed on the irradiated surfaces after strong uni-axial deformation (i.e., more than about 50% strain) of the photo-modified PU foils. Cell seeding experiments demonstrated that the VUV modified polymer foils strongly enhance cell adhesion and proliferation. Cells seeded onto microgrooves aligned their shapes and elongated in the direction of the grooves. A similar effect was observed for cells seeded on photo-modified PU foils subjected to cyclic mechanical stretching at lower strain levels (i.e., typically 10% strain) without groove-formation. The cells had also here an elongated shape, however they not always align in a defined direction relative to the stretching.

Comparative genome analysis of pathogenic and non-pathogenic Clavibacter strains reveals adaptations to their lifestyle

OpenAIRE

Załuga, Joanna; Stragier, Pieter; Baeyen, Steve; Haegeman, Annelies; Van Vaerenbergh, Johan; Maes, Martine; De Vos, Paul

2014-01-01

Background The genus Clavibacter harbors economically important plant pathogens infecting agricultural crops such as potato and tomato. Although the vast majority of Clavibacter strains are pathogenic, there is an increasing number of non-pathogenic isolates reported. Non-pathogenic Clavibacter strains isolated from tomato seeds are particularly problematic because they affect the current detection and identification tests for Clavibacter michiganensis subsp. michiganensis (Cmm), which is reg...

Chemical strain engineering of magnetism in PrVO3 thin films

Science.gov (United States)

Prellier, Wilfrid; Copie, Olivier; Varignon, Julien; Rotella, Helene; Steciuk, Gwladys; Boullay, Philippe; Pautrat, Alain; David, Adrian; Mercey, Bernard; Ghosez, Philippe

Transition metal oxides having a perovskite structure present a wide range of functional properties ranging from insulator-to-metal, ferroelectricity, colossal magnetoresistance, high-temperature superconductivity and multiferroicity. Such systems are generally characterized by strong electronic correlations, complex phase diagrams and competing ground states. In addition, small perturbation induced by external stimuli (electric or magnetic field, temperature, strain, pressure..) may change structure, and ultimately modify the physical properties. Here, we synthetize an orthorhombic perovskite praseodymium vanadate (PrVO3), which is grown on strontium titanate substrate. We show that the control of the content of oxygen vacancies, the so-called chemical strain, can indeed result in unexpected properties. We further demonstrate that the Néel temperature can be tuned using the same substrate in agreement with first-principles calculations, and demonstrate that monitoring the concentration of oxygen vacancies through the oxygen partial pressure or the growth temperature can produce a substantial macroscopic tensile strain of a few percents.

Effects of the strain background and autolysis process on the composition and biophysical properties of the cell wall from two different industrial yeasts.

Science.gov (United States)

Schiavone, Marion; Sieczkowski, Nathalie; Castex, Mathieu; Dague, Etienne; Marie François, Jean

2015-03-01

The Saccharomyces cerevisiae cell surface is endowed with some relevant technological properties, notably antimicrobial and biosorption activities. For these purposes, yeasts are usually processed and packaged in an 'autolysed/dried' formula, which may have some impacts on cell surface properties. In this report, we showed using a combination of biochemical, biophysical and molecular methods that the composition of the cell wall of two wine yeast strains was not altered by the autolysis process. In contrast, this process altered the nanomechanical properties as shown by a 2- to 4-fold increased surface roughness and to a higher adhesion to the atomic force microscope tips of the autolysed cells as compared to live yeast cells. Besides, we found that the two strains harboured differences in biomechanical properties that could be due in part to higher levels of mannan in one of them, and to the fact that the surface of this mannan-enriched strain is decorated with highly adhesive patches forming nanodomains. The presence of these nanodomains could be correlated with the upregulation of flocculin encoding FLO11 as well as to higher expression of few other genes encoding cell wall mannoproteins in this mannan-enriched strain as compared to the other strain. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permission@oup.com.

Historical Background of Turkey-Syria Relations in the Term of Social Geograpy

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Sedat BENEK

2016-06-01

Full Text Available Historical process between Syria and Turkey has always high tension. According to Turkey, Syria is the country,which has hosted the Turkish enemies, which causes problems in the sharing of water resources and geographically it is seen as ‘’enemy country’’ because of interfering in Turkey's territorial integrity; According to Syria, Turkey is "enemy" is because it doesn’t share water resources in a fair way and as supporters of western countries, claiming rights over their territory (Hatay. In short, for many years strained relations with Syria-Turkey relations , by signing of the Treaty of Adana in 1998, good relations has been established with unpredictable speed in a short time . Escalating positive relations between Turkey and Syria in the years 1998-2011, and relations has again strained the outbreak of the Syria Civil War in 2011, and was even worse off period before 1998. Therefore the main goal of this study "Historical Background of Turkey-Syria Relations in terms of Social Geography" is to examine the dynamics of it. For this purpose, treaties defining the Turkey-Syria relationship, the protocols, briefings given by officials were examined. Historical background of the two countries' relations in terms of social geography has been tried to put forward in chronological order

Breast tumor classification using axial shear strain elastography: a feasibility study

International Nuclear Information System (INIS)

Thitaikumar, Arun; Ophir, Jonathan; Mobbs, Louise M; Kraemer-Chant, Christina M; Garra, Brian S

2008-01-01

Recently, the feasibility of visualizing the characteristics of bonding at an inclusion-background boundary using axial-shear strain elastography was demonstrated. In this paper, we report a feasibility study on the utility of the axial-shear strain elastograms in the classification of in vivo breast tumor as being benign or malignant. The study was performed using data sets obtained from 15 benign and 15 malignant cases that were biopsy proven. A total of three independent observers were trained, and their services were utilized for the study. A total of 9 cases were used as training set and the remaining cases were used as testing set. The feature from the axial-shear strain elastogram, namely, the area of the axial-shear region, was extracted by the observers. The observers also outlined the tumor area on the corresponding sonogram, which was used to normalize the area of the axial-shear strain region. There are several observations that can be drawn from the results. First, the result indicates that the observers consistently (∼82% of the cases) noticed the characteristic pattern of the axial-shear strain distribution data as predicted in the previous simulation studies, i.e. alternating regions of positive and negative axial-shear strain values around the tumor-background interface. Second, the analysis of the result suggests that in approximately 57% of the cases in which the observers did not visualize tumor in the sonogram, the elastograms helped them to locate the tumor. Finally, the analysis of the result suggests that for the discriminant feature value of 0.46, the number of unnecessary biopsies could be reduced by 56.3% without compromising on sensitivity and on negative predictive value (NPV). Based on the results in this study, feature values greater than 0.75 appear to be indicative of malignancy, while values less than 0.46 to be indicative of benignity. Feature values between 0.46 and 0.75 may result in an overlap between benign and malignant

Nest covering in plovers: How modifying the visual environment influences egg camouflage.

Science.gov (United States)

Troscianko, Jolyon; Wilson-Aggarwal, Jared; Spottiswoode, Claire N; Stevens, Martin

2016-10-01

Camouflage is one of the most widespread antipredator defences, and its mechanistic basis has attracted considerable interest in recent years. The effectiveness of camouflage depends on the interaction between an animal's appearance and its background. Concealment can therefore be improved by changes to an animal's own appearance, by behaviorally selecting an optimal background, or by modifying the background to better match the animal's own appearance. Research to date has largely focussed on the first of these mechanisms, whereas there has been little work on the second and almost none on the third. Even though a number of animal species may potentially modify their environment to improve individual-specific camouflage, this has rarely if ever been quantitatively investigated, or its adaptive value tested. Kittlitz's plovers (Charadrius pecuarius) use material (stones and vegetation) to cover their nests when predators approach, providing concealment that is independent of the inflexible appearance of the adult or eggs, and that can be adjusted to suit the local surrounding background. We used digital imaging and predator vision modeling to investigate the camouflage properties of covered nests, and whether their camouflage affected their survival. The plovers' nest-covering materials were consistent with a trade-off between selecting materials that matched the color of the eggs, while resulting in poorer nest pattern and contrast matching to the nest surroundings. Alternatively, the systematic use of materials with high-contrast and small-pattern grain sizes could reflect a deliberate disruptive coloration strategy, whereby high-contrast material breaks up the telltale outline of the clutch. No camouflage variables predicted nest survival. Our study highlights the potential for camouflage to be enhanced by background modification. This provides a flexible system for modifying an animal's conspicuousness, to which the main limitation may be the available

Rheological characterization of geopolymer binder modified by organic resins

Science.gov (United States)

Cekalová, M.; Kovárík, T.; Rieger, D.

2017-01-01

The purpose of this study is going to investigate properties of alkali-activated powder (calcined kaoilinitic clay and granulated blast furnace slag) prepared as a geopolymer paste and modified by various amount of organic resin. Hybrid organic-inorganic binders were prepared as a mix of organic resin and geopolymer inorganic paste under vacuum conditions. The process of solidification was investigated by measurements of storage (G’) and loss modulus ( G’) in torsion. The measurement was conducted in oscillatory mode by constant strain of 0.01 %. This strain is set in linear visco-elastic region for minimization influence of paste structure. The effect of organic resin is presented and determined by changes of viscosity (‘n*), modules in torsion and tangent of loss angle (tan 8). Results indicate that addition of organic resin significantly affects the initial viscosity and hardening kinetics.

Tunnel Magnetoresistance Sensors with Magnetostrictive Electrodes: Strain Sensors.

Science.gov (United States)

Tavassolizadeh, Ali; Rott, Karsten; Meier, Tobias; Quandt, Eckhard; Hölscher, Hendrik; Reiss, Günter; Meyners, Dirk

2016-11-11

Magnetostrictive tunnel magnetoresistance (TMR) sensors pose a bright perspective in micro- and nano-scale strain sensing technology. The behavior of TMR sensors under mechanical stress as well as their sensitivity to the applied stress depends on the magnetization configuration of magnetic tunnel junctions (MTJ)s with respect to the stress axis. Here, we propose a configuration resulting in an inverse effect on the tunnel resistance by tensile and compressive stresses. Numerical simulations, based on a modified Stoner-Wohlfarth (SW) model, are performed in order to understand the magnetization reversal of the sense layer and to find out the optimum bias magnetic field required for high strain sensitivity. At a bias field of -3.2 kA/m under a 0.2 × 10 - 3 strain, gauge factors of 2294 and -311 are calculated under tensile and compressive stresses, respectively. Modeling results are investigated experimentally on a round junction with a diameter of 30 ± 0.2 μ m using a four-point bending apparatus. The measured field and strain loops exhibit nearly the same trends as the calculated ones. Also, the gauge factors are in the same range. The junction exhibits gauge factors of 2150 ± 30 and -260 for tensile and compressive stresses, respectively, under a -3.2 kA/m bias magnetic field. The agreement of the experimental and modeling results approves the proposed configuration for high sensitivity and ability to detect both tensile and compressive stresses by a single TMR sensor.

Mobilomics in Saccharomyces cerevisiae strains

Science.gov (United States)

2013-01-01

Background Mobile Genetic Elements (MGEs) are selfish DNA integrated in the genomes. Their detection is mainly based on consensus–like searches by scanning the investigated genome against the sequence of an already identified MGE. Mobilomics aims at discovering all the MGEs in a genome and understanding their dynamic behavior: The data for this kind of investigation can be provided by comparative genomics of closely related organisms. The amount of data thus involved requires a strong computational effort, which should be alleviated. Results Our approach proposes to exploit the high similarity among homologous chromosomes of different strains of the same species, following a progressive comparative genomics philosophy. We introduce a software tool based on our new fast algorithm, called regender, which is able to identify the conserved regions between chromosomes. Our case study is represented by a unique recently available dataset of 39 different strains of S.cerevisiae, which regender is able to compare in few minutes. By exploring the non–conserved regions, where MGEs are mainly retrotransposons called Tys, and marking the candidate Tys based on their length, we are able to locate a priori and automatically all the already known Tys and map all the putative Tys in all the strains. The remaining putative mobile elements (PMEs) emerging from this intra–specific comparison are sharp markers of inter–specific evolution: indeed, many events of non–conservation among different yeast strains correspond to PMEs. A clustering based on the presence/absence of the candidate Tys in the strains suggests an evolutionary interconnection that is very similar to classic phylogenetic trees based on SNPs analysis, even though it is computed without using phylogenetic information. Conclusions The case study indicates that the proposed methodology brings two major advantages: (a) it does not require any template sequence for the wanted MGEs and (b) it can be applied to

Investigation of carbon storage regulation network (csr genes) and phenotypic differences between acid sensitive and resistant Escherichia coli O157:H7 strains

Science.gov (United States)

Background: Escherichia coli O157:H7 and related serotype strains have previously been shown to vary in acid resistance, however, little is known about strain specific mechanisms of acid resistance. We examined sensitive and resistant E. coli strains to determine the effects of growth in minimal and...

Modified Sucksmith balances for ferromagnetic and paramagnetic measurements

Energy Technology Data Exchange (ETDEWEB)

Lundquist, N; Myers, H P

1962-02-15

Two balances, one for measurement of ferromagnetic magnetisation, the other for paramagnetic susceptibility measurements, are described. Designs are based on Sucksmith's ring balance but the ring and optical lever system of the latter has been replaced by a strain gauge bridge, which allows the force on the magnetic specimens to be determined via potentiometer readings. The modified balances are very robust, insensitive to vibration and, if desired, suitable for direct recording. Relative accuracies of 0.3 % and 0.5 % are obtained respectively for the ferromagnetic and paramagnetic systems.

Relation between motility, accelerated aging and gene expression in selected Drosophila strains under hypergravity conditions

NARCIS (Netherlands)

Serrano, P.; van Loon, J.J.W.A.; Javier Medina, F.; Herranz, R.

2013-01-01

Motility and aging in Drosophila have proven to be highly modified under altered gravity conditions (both in space and ground simulation facilities). In order to find out how closely connected they are, five strains with altered geotactic response or survival rates were selected and exposed to an

Creep-fatigue evaluation method for modified 9Cr-1Mo steel

International Nuclear Information System (INIS)

Wada, Y.; Aoto, K.

1997-01-01

As creep-fatigue evaluation methods on normalized and tempered Modified 9Cr-1Mo steel for design use, the time fraction rule and the simplified conventional ductility exhaustion rule are investigated for the prediction of tension strain hold creep-fatigue damage of this material. For the above investigation, stress relaxation behaviour during strain hold has to be analyzed using stress-strain-time relation. The initial value of stress relaxation was determined by cyclic stress-strain curves in continuous cycling fatigue tests. Cyclic stress-strain behaviour of Mod.9Cr-1Mo(NT) steel is different from that of austenitic stainless steels, so this effect was considered. Stress relaxation analysis was performed using static creep strain-time relation and conventional hardening rule. The time fraction by using the above stress relaxation analysis results can give good prediction for creep-fatigue life of Mod.9Cr-1Mo(NT) steel. For design use it is practical to be able to estimate creep damages conservatively by both strain behaviour of cyclic plastic (in continuous cycling fatigue tests) and monotonic creep (in standard creep tests). The life reduction by strain hold at the minimum peak of compressive stress in creep-fatigue tests was examined, and this effects can be evaluated by the relationship between the location of oxidation and the effective deformation at crack tip. In an accelerated oxidation environment, for example in high temperature and high pressure steam, a different approach for life reduction should be developed based on the mechanism of growth of oxide and crack growth with oxidation. However, in the creep damage dominant region, its effect is saturated and the effect of cavity growth along grain boundary becomes dominant for long-term strain hold in the high temperature conditions. (author). 6 refs, 6 figs

Antibiotic-modifying activity of riachin, a non-cyanogenic cyanoglycoside extracted from Bauhinia pentandra

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Farias PAM

2015-06-01

Full Text Available Pablo Antonio Maia de Farias,1,3 Fernando Gomes Figueredo,2,3 Aline Maria Brito Lucas,3 Rafael Barbosa de Moura,3 Henrique Douglas Melo Coutinho,2 Tania Maria Sarmento da Silva,4 Ana Luiza de Aguiar Rocha Martin,2,3 Marta Maria de França Fonteles1 1Development and Technological Innovation in Medicines, Universidade Federal do Ceará – UFC, Fortaleza-CE, 2College of Biomedicine, Faculdade Leão Sampaio-FLS, 3College of Pharmacy, Faculdade de Medicina Estácio de Juazeiro do Norte-Estácio, Juazeiro do Norte-CE, 4Department of Molecular Sciences, Universidade Federal Rural de Pernambuco, Recife, PE, Brazil Background: The search for new active compounds from the Brazilian flora has intensified in recent years, especially for new drugs with antibiotic potential. Accordingly, the aim of this study was to determine whether riachin has antibiotic activity in itself or is able to modulate the activity of conventional antibiotics.Methods: A non-cyanogenic cyanoglycoside known as riachin was isolated from Bauhinia pentandra, and was tested alone and in combination with three antibiotics (clindamycin, amikacin, and gentamicin against multiresistant bacterial strains (Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus aureus.Results: Riachin did not show significant antibiotic activity when tested alone against any strain (P>0.05. However, when combined with conventional antibiotics, it showed drug-modifying activity against strains of S. aureus exposed to clindamycin (P<0.001 as well as against P. aeruginosa exposed to amikacin (P<0.001. Although riachin did not show direct antibiotic activity, it had synergistic activity when combined with amikacin or clindamycin. The mechanism of action of this synergism is under investigation.Conclusion: The results of this work demonstrate that some substances of natural origin can enhance the effectiveness of certain antibiotics, which means a substantial reduction in the drug dose required and

A low cycle fatigue model for low carbon manganese steel including the effect of dynamic strain aging

Energy Technology Data Exchange (ETDEWEB)

Huang, Zhi Yong, E-mail: huangzy@scu.edu.cn [Sichuan University, School of Aeronautics and Astronautics, No.29 Jiuyanqiao Wangjiang Road, Chengdu 610064 (China); Wagner, Danièle [Université Paris Ouest Nanterre La Défense (France); Wang, Qing Yuan; Khan, Muhammad Kashif [Sichuan University, School of Aeronautics and Astronautics, No.29 Jiuyanqiao Wangjiang Road, Chengdu 610064 (China); Chaboche, Jean–Louis [ONERA, DMSM, 29 avenue de la Division Lecerc, F-92320, Chatillon (France)

2016-01-27

Carbon–manganese steel A48 (French standards) is used in steam generator pipes of the nuclear power plant where it is subjected to the cyclic thermal load. The Dynamic Strain Aging (DSA) influences the mechanical behavior of the steel in low cycle fatigue (LCF) at favorable temperature and strain rate. The peak stress of A48 steel experiences hardening–softening–hardening (HSH) evolution at 200 °C and 0.4% s{sup −1} strain rate in fatigue loading. In this study, isotropic and kinematic hardening rules with DSA effect have been modified. The HSH evolution of cyclic stress associated with cumulative plastic deformation has also been estimated.

Experimental Study on Bond-Slip Behavior of Bamboo Bolt-Modified Slurry Interface under Pull-Out Load

Directory of Open Access Journals (Sweden)

Wei Lu

2018-01-01

Full Text Available This paper presents an analysis of bamboo bolt-modified slurry interfaces based on 26 in situ axial pull-out tests intended to highlight the mechanical behavior of interface under a fracture mode. Three impact factors are analyzed: anchorage length, bolt diameter, and bolt hole diameter, using the same materials of bamboo and modified slurry. The result shows that the interface between the bamboo bolt and anchoring agent is the control interface of an anchorage system, and the local behavior of the interface involves four stages: elastic, soften, friction, and decoupling. Distribution law and change trend of slippage, stress, and strain of anchoring interface along with the axial direction of an anchor bolt were analyzed. The result shows that there is effective anchoring length limit in this kind of interface, and that the complete decoupling phenomenon should not be neglected. Through a comparative analysis of the existing bond-slip model and interface bond-slip curve, and considering the correspondence of the strain-slip curve and trilinear bond-slip model simultaneously, a modified trilinear bond-slip model has been proposed. The friction section of this model is limited, and shearing stress in the complete decoupling section is zero.

Note on bouncing backgrounds

Science.gov (United States)

de Haro, Jaume; Pan, Supriya

2018-05-01

The theory of inflation is one of the fundamental and revolutionary developments of modern cosmology that became able to explain many issues of the early Universe in the context of the standard cosmological model (SCM). However, the initial singularity of the Universe, where physics is indefinite, is still obscure in the combined SCM +inflation scenario. An alternative to SCM +inflation without the initial singularity is thus always welcome, and bouncing cosmology is an attempt at that. The current work is thus motivated to investigate the bouncing solutions in modified gravity theories when the background universe is described by the spatially flat Friedmann-Lemaître-Robertson-Walker (FLRW) geometry. We show that the simplest way to obtain the bouncing cosmologies in such spacetime is to consider some kind of Lagrangian whose gravitational sector depends only on the square of the Hubble parameter of the FLRW universe. For these modified Lagrangians, the corresponding Friedmann equation, a constraint in the dynamics of the Universe, depicts a curve in the phase space (H ,ρ ), where H is the Hubble parameter and ρ is the energy density of the Universe. As a consequence, a bouncing cosmology is obtained when this curve is closed and crosses the axis H =0 at least twice, and whose simplest particular example is the ellipse depicting the well-known holonomy corrected Friedmann equation in loop quantum cosmology (LQC). Sometimes, a crucial point in such theories is the appearance of the Ostrogradski instability at the perturbative level; however, fortunately enough, in the present work, as long as the linear level of perturbations is concerned, this instability does not appear, although it may appear at the higher order of perturbations.

Myocardial Strain Analysis by 2-Dimensional Speckle Tracking Echocardiography Improves Diagnostics of Coronary Artery Stenosis in Stable Angina Pectoris

DEFF Research Database (Denmark)

Biering-Sørensen, Tor; Hoffmann, Soren; Mogelvang, Rasmus

2014-01-01

BACKGROUND: Two-dimensional strain echocardiography detects early signs of left ventricular dysfunction; however, it is unknown whether myocardial strain analysis at rest in patients with suspected stable angina pectoris predicts the presence of coronary artery disease (CAD). METHODS AND RESULTS...... echocardiography was performed in the 3 apical projections. Peak regional longitudinal systolic strain was measured in 18 myocardial sites and averaged to provide global longitudinal peak systolic strain. Duke score, including ST-segment depression, chest pain, and exercise capacity, was used as the outcome...

Generation of a restriction minus enteropathogenic Escherichia coli E2348/69 strain that is efficiently transformed with large, low copy plasmids

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Ward Jordan D

2008-08-01

Full Text Available Abstract Background Many microbes possess restriction-modification systems that protect them from parasitic DNA molecules. Unfortunately, the presence of a restriction-modification system in a given microbe also hampers genetic analysis. Although plasmids can be successfully conjugated into the enteropathogenic Escherichia coli strain E2348/69 and optimized protocols for competent cell preparation have been developed, we found that a large, low copy (~15 bioluminescent reporter plasmid, pJW15, that we modified for use in EPEC, was exceedingly difficult to transform into E2348/69. We reasoned that a restriction-modification system could be responsible for the low transformation efficiency of E2348/69 and sought to identify and inactivate the responsible gene(s, with the goal of creating an easily transformable strain of EPEC that could complement existing protocols for genetic manipulation of this important pathogen. Results Using bioinformatics, we identified genes in the unfinished enteropathogenic Escherichia coli (EPEC strain E2348/69 genome whose predicted products bear homology to the HsdM methyltransferases, HsdS specificity subunits, and HsdR restriction endonucleases of type I restriction-modification systems. We constructed a strain carrying a deletion of the conserved enzymatic domain of the EPEC HsdR homologue, NH4, and showed that its transformation efficiency was up to four orders of magnitude higher than that of the parent strain. Further, the modification capacity of NH4 remained intact, since plasmids that were normally recalcitrant to transformation into E2348/69 could be transformed upon passage through NH4. NH4 was unaffected in virulence factor production, since bundle forming pilus (BFP subunits and type III secreted (T3S proteins were present at equivalent levels to those seen in E2348/69. Further, NH4 was indistinguishable from E2348/69 in tissue culture infection model assays of localized adherence and T3S. Conclusion We

The role of strain localization in the fracture of irradiated pressure tube material

International Nuclear Information System (INIS)

Dutton, R.

1989-04-01

This report reviews those phenomena that lead to strain localization in zirconium alloys, with particular reference to the role played by the formation of shear bands in fracture processes. The important influence of plastic deformation, in general, on fracture mechanisms is emphasized. This is to be expected when elastic-plastic fracture mechanics is the chosen analytical technique. Intensely inhomogeneous characteristics of strain localization cause an abrupt bifurcation in the evolution of deformation strain and lead to plastic instability linked with intrinsic material behaviour (e.g., work softening) or of geometric origin (e.g., localized necking). Both of these effects are discussed in relation to measurable deformation parameters, such as the work hardening rate and strain rate sensitivity, which determine the degree of resistance to plastic instability. The modifying effect of irradiation on these quantities is given specific attention, the appropriate literature pertaining to Zircaloy and Zr-2.5% Nb being reviewed. Recommendations are made for a combined experimental and theoretical program to characterize strain localization and reduced ductility in irradiated cold-worked Zr-2.5% Nb pressure tube material. The relationship between the deformation properties and the fracture behaviour is discussed

Electric field-induced valley degeneracy lifting in uniaxial strained graphene: Evidence from magnetophonon resonance

Science.gov (United States)

Assili, Mohamed; Haddad, Sonia; Kang, Woun

2015-03-01

A double peak structure in the magnetophonon resonance (MPR) spectrum of uniaxial strained graphene, under crossed electric and magnetic fields, is predicted. We focus on the Γ point optical phonon modes coupled to the inter-Landau level transitions 0 ⇆±1 where MPR is expected to be more pronounced at high magnetic field. We derive the frequency shifts and the broadenings of the longitudinal and transverse optical phonon modes taking into account the effect of the strain modified electronic spectrum on the electron-phonon coupling. We show that the MPR line for a given phonon mode acquires a double peak structure originating from the twofold valley degeneracy lifting. The latter is due to the different Landau level spacings in the two Dirac valleys resulting from the simultaneous action of the inplane electric field and the strain-induced Dirac cone tilt. We discuss the role of some key parameters such as disorder, strain, doping, and electric field amplitude on the emergence of the double peak structure.

Antimicrobial resistance and production of biofilms in clinical isolates of coagulase-negative Staphylococcus strains.

Science.gov (United States)

de Allori, María Cristina Gaudioso; Jure, María Angela; Romero, Cintia; de Castillo, Marta Elena Cecilia

2006-08-01

Coagulase-negative Staphylococcus (CNS) strains are frequently associated with bacteremia and hospital-acquired infections. 293 CNS strains were isolated from 744 samples from a dialysis center in S. M. de Tucumán, Argentina, from hemocultures, catheters and urine and identified as S. epidermidis, S. haemolyticus, S. saprophyticus, S. hominis and S. cohnii. 13 antibiotics were tested for antibacterial resistance. 75% of S. saprophyticus, 66% of S. epidermidis and 57% of S. haemolyticus was resistant to erythromycin and 50% of S. haemolyticus was resistant to ciprofloxacin. OXA resistance was found in 43% of S. haemolyticus. Presence of PBP 2a in OXA-R strains was confirmed with the modified agglutination assay (MRSA) and presence of the mecA gene. 15 strains with intermediate halos for vancomycin and teicoplanin showed a MIC in solid and liquid medium resistance to methicillin and biofilm production are decisive for a prompt and appropriate antimicrobial therapy and limited use of inappropriate glycopeptides.

Existence of stable wormholes on a non-commutative-geometric background in modified gravity

Energy Technology Data Exchange (ETDEWEB)

Zubair, M.; Mustafa, G. [COMSATS, Institute of Information Technology, Department of Mathematics, Lahore (Pakistan); Waheed, Saira [Prince Mohammad Bin Fahd University, Al Khobar (Saudi Arabia); Abbas, G. [The Islamia University of Bahawalpur, Department of Mathematics, Bahawalpur (Pakistan)

2017-10-15

In this paper, we discuss spherically symmetric wormhole solutions in f(R, T) modified theory of gravity by introducing well-known non-commutative geometry in terms of Gaussian and Lorentzian distributions of string theory. For analytic discussion, we consider an interesting model of f(R, T) gravity defined by f(R, T) = f{sub 1}(R) + λT. By taking two different choices for the function f{sub 1}(R), that is, f{sub 1}(R) = R and f{sub 1}(R) = R + αR{sup 2} + γR{sup n}, we discuss the possible existence of wormhole solutions. In the presence of non-commutative Gaussian and Lorentzian distributions, we get exact and numerical solutions for both these models. By taking appropriate values of the free parameters, we discuss different properties of these wormhole models analytically and graphically. Further, using an equilibrium condition, it is found that these solutions are stable. Also, we discuss the phenomenon of gravitational lensing for the exact wormhole model and it is found that the deflection angle diverges at the wormhole throat. (orig.)

A modified Janus cassette (Sweet Janus to improve allelic replacement efficiency by high-stringency negative selection in Streptococcus pneumoniae.

Directory of Open Access Journals (Sweden)

Yuan Li

Full Text Available The Janus cassette permits marker-free allelic replacement or knockout in streptomycin-resistant Streptococcus pneumoniae (pneumococcus through sequential positive and negative selection. Spontaneous revertants of Janus can lead to high level of false-positives during negative selection, which necessitate a time-consuming post-selection screening process. We hypothesized that an additional counter-selectable marker in Janus would decrease the revertant frequency and reduce false-positives, since simultaneous reversion of both counter-selectable makers is much less likely. Here we report a modified cassette, Sweet Janus (SJ, in which the sacB gene from Bacillus subtilis conferring sucrose sensitivity is added to Janus. By using streptomycin and sucrose simultaneously as selective agents, the frequency of SJ double revertants was about 105-fold lower than the frequency of Janus revertants. Accordingly, the frequency of false-positives in the SJ-mediated negative selection was about 100-fold lower than what was seen for Janus. Thus, SJ enhances negative selection stringency and can accelerate allelic replacement in pneumococcus, especially when transformation frequency is low due to strain background or suboptimal transformation conditions. Results also suggested the sacB gene alone can function as a counter-selectable marker in the Gram-positive pneumococcus, which will have the advantage of not requiring a streptomycin-resistant strain for allelic replacement.

Comparative genomic characterization of citrus-associated Xylella fastidiosa strains

Directory of Open Access Journals (Sweden)

Nunes Luiz R

2007-12-01

Full Text Available Abstract Background The xylem-inhabiting bacterium Xylella fastidiosa (Xf is the causal agent of Pierce's disease (PD in vineyards and citrus variegated chlorosis (CVC in orange trees. Both of these economically-devastating diseases are caused by distinct strains of this complex group of microorganisms, which has motivated researchers to conduct extensive genomic sequencing projects with Xf strains. This sequence information, along with other molecular tools, have been used to estimate the evolutionary history of the group and provide clues to understand the capacity of Xf to infect different hosts, causing a variety of symptoms. Nonetheless, although significant amounts of information have been generated from Xf strains, a large proportion of these efforts has concentrated on the study of North American strains, limiting our understanding about the genomic composition of South American strains – which is particularly important for CVC-associated strains. Results This paper describes the first genome-wide comparison among South American Xf strains, involving 6 distinct citrus-associated bacteria. Comparative analyses performed through a microarray-based approach allowed identification and characterization of large mobile genetic elements that seem to be exclusive to South American strains. Moreover, a large-scale sequencing effort, based on Suppressive Subtraction Hybridization (SSH, identified 290 new ORFs, distributed in 135 Groups of Orthologous Elements, throughout the genomes of these bacteria. Conclusion Results from microarray-based comparisons provide further evidence concerning activity of horizontally transferred elements, reinforcing their importance as major mediators in the evolution of Xf. Moreover, the microarray-based genomic profiles showed similarity between Xf strains 9a5c and Fb7, which is unexpected, given the geographical and chronological differences associated with the isolation of these microorganisms. The newly

Resistance pattern of Helicobacter pylori strains to clarithromycin, metronidazole, and amoxicillin in Isfahan, Iran

Directory of Open Access Journals (Sweden)

Farzad Khademi

2013-01-01

Full Text Available Background: Helicobacter pylori (H. pylori resistance to antibiotics has become a global problem and is an important factor in determining the outcome of treatment of infected patients. The purpose of this study was to determine the H. pylori resistance to clarithromycin, metronidazole, and amoxicillin in gastrointestinal disorders patients. Materials and Methods: In this study, a total of 260 gastric antrum biopsy specimens were collected from patients with gastrointestinal disorders who referred to Endoscopy Section of the Isfahan Hospitals. The E-test and Modified Disk Diffusion Method (MDDM were used to verify the prevalence of antibiotic resistance in 78 H. pylori isolates to the clarithromycin, metronidazole, and amoxicillin. Results: H. pylori resistance to clarithromycin, metronidazole, and amoxicillin were 15.3, 55.1, and 6.4%, respectively. In this studyΈ we had one multidrug resistance (MDR isolates from patient with gastritis and peptic ulcer disease. Conclusion: Information on antibiotic susceptibility profile plays an important role in empiric antibiotic treatment and management of refractive cases. According to the results obtained in this study, H. pylori resistance to clarithromycin and metronidazole was relatively high. MDR strains are emerging and will have an effect on the combination therapy.

A new laboratory cultivation of Paramecium bursaria using non-pathogenic bacteria strains.

Science.gov (United States)

Bator, Tomasz

2010-01-01

In most studies dealing with the laboratory cultivation of paramecia (Paramecium bursaria), Klebsiella pneumoniae bacteria are used to inoculate the medium. However, Klebsiella pneumoniae is a typical pathogen, and its use is always associated with a risk of infection. The aim of the present research was to examine non-pathogenic bacteria strains as components of the medium for Paramecium bursaria. The paramecia were incubated on lettuce infusions bacterized with different bacteria strains: Bacillus subtilis DSM 10, Bacillus megaterium DSM 32, Escherichia coli DSM 498, Micrococcus luteus DSM 348. A strain derived from the natural habitat of Paramecium bursaria was used as the control one. Experiments were conducted under constant light and in the dark. Paramecia cells were counted under a stereomicroscope on consecutive days of incubation. The obtained results show that the most intensive growth of Paramecium bursaria occurs in the presence of Escherichia coli DSM 498. The use of this strain as a component of the medium allows one to obtain a high number of ciliates regardless of the light conditions. It can be concluded that the Paramecium bursaria cultivation procedure can be modified by using the non-pathogenic bacteria strain Escherichia coli DSM 498 instead of Klebsiella pneumoniae.

Experimental Study and Modelling of Poly (Methyl Methacrylate) and Polycarbonate Compressive Behavior from Low to High Strain Rates

Science.gov (United States)

El-Qoubaa, Z.; Colard, L.; Matadi Boumbimba, R.; Rusinek, A.

2018-03-01

This paper concerns an experimental investigation of Polycarbonate and Poly (methyl methacrylate) compressive behavior from low to high strain rates. Experiments were conducted from 0.001/s to ≈ 5000/s for PC and from 0.001/s to ≈ 2000/s for PMMA. The true strain-stress behavior is established and analyzed at various stain rates. Both PC and PMMA mechanical behavior appears as known, to be strain rate and temperature dependent. The DSGZ model is selected for modelling the strain-stress curves while the yield stress is reproduced using the cooperative model and a modified Eyring equation based on Eyring first process theory. All the three models predictions are in agreement with experiments performed on PC and PMMA.

Light from electron avalanches and background rejection in X-ray astronomy

International Nuclear Information System (INIS)

Siegmund, O.H.W.; Sanford, P.W.; Mason, I.M.; Culhane, J.L.; Cockshott, R.

1980-01-01

A modified version of the parallel plate imaging proportional counter, developed to register images of cosmic x-ray sources in the focal planes of x-ray telescopes, has been constructed to investigate the application of risetime discrimination to the scintillation pulses caused by the electron avalanche process. It is shown that efficient background event rejection (> 90%) is achieved and the application of this system for x-ray astronomy is discussed. (U.K.)

General Relativity solutions in modified gravity

Science.gov (United States)

Motohashi, Hayato; Minamitsuji, Masato

2018-06-01

Recent gravitational wave observations of binary black hole mergers and a binary neutron star merger by LIGO and Virgo Collaborations associated with its optical counterpart constrain deviation from General Relativity (GR) both on strong-field regime and cosmological scales with high accuracy, and further strong constraints are expected by near-future observations. Thus, it is important to identify theories of modified gravity that intrinsically possess the same solutions as in GR among a huge number of theories. We clarify the three conditions for theories of modified gravity to allow GR solutions, i.e., solutions with the metric satisfying the Einstein equations in GR and the constant profile of the scalar fields. Our analysis is quite general, as it applies a wide class of single-/multi-field scalar-tensor theories of modified gravity in the presence of matter component, and any spacetime geometry including cosmological background as well as spacetime around black hole and neutron star, for the latter of which these conditions provide a necessary condition for no-hair theorem. The three conditions will be useful for further constraints on modified gravity theories as they classify general theories of modified gravity into three classes, each of which possesses i) unique GR solutions (i.e., no-hair cases), ii) only hairy solutions (except the cases that GR solutions are realized by cancellation between singular coupling functions in the Euler-Lagrange equations), and iii) both GR and hairy solutions, for the last of which one of the two solutions may be selected dynamically.

Nonlinear Finite Strain Consolidation Analysis with Secondary Consolidation Behavior

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Jieqing Huang

2014-01-01

Full Text Available This paper aims to analyze nonlinear finite strain consolidation with secondary consolidation behavior. On the basis of some assumptions about the secondary consolidation behavior, the continuity equation of pore water in Gibson’s consolidation theory is modified. Taking the nonlinear compressibility and nonlinear permeability of soils into consideration, the governing equation for finite strain consolidation analysis is derived. Based on the experimental data of Hangzhou soft clay samples, the new governing equation is solved with the finite element method. Afterwards, the calculation results of this new method and other two methods are compared. It can be found that Gibson’s method may underestimate the excess pore water pressure during primary consolidation. The new method which takes the secondary consolidation behavior, the nonlinear compressibility, and nonlinear permeability of soils into consideration can precisely estimate the settlement rate and the final settlement of Hangzhou soft clay sample.

Physico-chemical traits of raw and cooked fillets of rainbow trout (Oncorhynchus mykiss from different strains and farms

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Roberta Martelli

2014-09-01

Full Text Available Fillets and cooking yields, water holding capacity, textural properties, colour, proximate composition, collagen and fatty acids of five strains (IT1, IT2, IT3, USA, UK of rainbow trout, Oncorhynchus mykiss, reared in three farms (F1, F2, F3, were measured before and after cooking. Physico-chemical parameters of the strains greatly differed both in raw and cooked state. IT2 and USA recorded the highest yields. IT2 distinguished from the other strains, showing lowest values of hardness, chewiness, gumminess and springiness. It also had brighter and less pigmented flesh with low fat, mainly in the raw state. USA strain showed the most valuable traits in terms of texture and colour, and had higher fat and collagen content in flesh. The physico-chemical profile of each strain was differently modified by cooking. USA strain maintained a positive texture and colour profile after cooking and its quality was the best.

Autosomal male determination in a spinosad-resistant housefly strain from Denmark

DEFF Research Database (Denmark)

Højland, Dorte H; Scott, Jeffrey G; Vagn Jensen, Karl-Martin

2014-01-01

males in this strain. The factor responsible for spinosad resistance in the strain is unknown, but previous studies suggest a role of cytochrome P450s for detoxification of spinosad. Sex determination in the housefly is controlled by a male-determining factor (M), either located on the Y chromosome......BACKGROUND The housefly, Musca domestica L., is a global pest and has developed resistance to most insecticides applied for its control. The insecticide spinosad plays an important role in housefly control. Females of the Danish housefly strain 791spin are threefold more resistant to spinosad than...... of resistance to spinosad. Sex determination in 791spin is due to a male factor on autosome 3. CONCLUSIONS The most likely explanation for the differentiation of spinosad resistance between males and females is a recessive spinosad resistance factor on autosome III. © 2013 Society of Chemical Industry...

Ultrasensitive tunability of the direct bandgap of 2D InSe flakes via strain engineering

Science.gov (United States)

Li, Yang; Wang, Tianmeng; Wu, Meng; Cao, Ting; Chen, Yanwen; Sankar, Raman; Ulaganathan, Rajesh K.; Chou, Fangcheng; Wetzel, Christian; Xu, Cheng-Yan; Louie, Steven G.; Shi, Su-Fei

2018-04-01

InSe, a member of the layered materials family, is a superior electronic and optical material which retains a direct bandgap feature from the bulk to atomically thin few-layers and high electronic mobility down to a single layer limit. We, for the first time, exploit strain to drastically modify the bandgap of two-dimensional (2D) InSe nanoflakes. We demonstrated that we could decrease the bandgap of a few-layer InSe flake by 160 meV through applying an in-plane uniaxial tensile strain to 1.06% and increase the bandgap by 79 meV through applying an in-plane uniaxial compressive strain to 0.62%, as evidenced by photoluminescence (PL) spectroscopy. The large reversible bandgap change of ~239 meV arises from a large bandgap change rate (bandgap strain coefficient) of few-layer InSe in response to strain, ~154 meV/% for uniaxial tensile strain and ~140 meV/% for uniaxial compressive strain, representing the most pronounced uniaxial strain-induced bandgap strain coefficient experimentally reported in 2D materials. We developed a theoretical understanding of the strain-induced bandgap change through first-principles DFT and GW calculations. We also confirmed the bandgap change by photoconductivity measurements using excitation light with different photon energies. The highly tunable bandgap of InSe in the infrared regime should enable a wide range of applications, including electro-mechanical, piezoelectric and optoelectronic devices.

Sister chromatid exchanges (SCEs) in lymphocytes of inhabitants in high background radiation area

International Nuclear Information System (INIS)

Li Jinsheng; Zheng Qiaoling

1985-01-01

Blood samples were taken from 126 students of 15-16 years old, living in the high background radiation area, and from 124 controls of the same age range, living in the normal background radiation area. All students were interviewed for evaluation of their health status. Whole blood cultures were done with RPMI 1640 medium supplemented with 20% fetal calf serum and antibiotics, The culture were incubated for 54-56 h in the presence of BrdU (10 μg/ml). Metaphases were stained for SCE using a modified techniqu of perry and Wolff. From each person 20 second division metaphases were analysed for SCEs. The average frequencies of SCEs observed in the high background group and the control group are presented. More SCEs were observed in the high background group than in the control with a statistically signigicant difference. In regard to the sex factor, it was found that the SCE frequencies in both sexes of the high background group were slightly higher than those in the control group. These findings suggest that continuous low-level irradiation by the high background radiation may induce increased frequency of SCEs

A comparative study of P450 gene expression in field and laboratory Musca domestica L. strains

DEFF Research Database (Denmark)

Højland, Dorte Heidi; Vagn Jensen, Karl-Martin; Kristensen, Michael

2014-01-01

BACKGROUND The housefly is a global pest that has developed resistance to most insecticides applied for its control. Resistance has been associated with cytochrome P450 monooxygenases (P450s). The authors compare the expression of six genes possibly associated with insecticide resistance in three...... unselected strains: a multiresistant strain (791a), a neonicotinoid-resistant strain (766b) and a new field strain (845b). RESULTS CYP4G2 was highly expressed throughout the range of strains and proved to be the one of the most interesting expression profiles of all P450s analysed. CYP6G4 was expressed up...... to 11-fold higher in 766b than in WHO-SRS. Significant differences between expression of P450 genes between F1 flies from 845b and established laboratory strains were shown. In general, P450 gene expression in 845b was 2–14-fold higher than in the reference strain (P

Lipid production in association of filamentous fungi with genetically modified cyanobacterial cells.

Science.gov (United States)

Miranda, Ana F; Taha, Mohamed; Wrede, Digby; Morrison, Paul; Ball, Andrew S; Stevenson, Trevor; Mouradov, Aidyn

2015-01-01

Numerous strategies have evolved recently for the generation of genetically modified or synthetic microalgae and cyanobacteria designed for production of ethanol, biodiesel and other fuels. In spite of their obvious attractiveness there are still a number of challenges that can affect their economic viability: the high costs associated with (1) harvesting, which can account for up to 50 % of the total biofuel's cost, (2) nutrients supply and (3) oil extraction. Fungal-assisted bio-flocculation of microalgae is gaining increasing attention due to its high efficiency, no need for added chemicals and low energy inputs. The implementation of renewable alternative carbon, nitrogen and phosphorus sources from agricultural wastes and wastewaters for growing algae and fungi makes this strategy economically attractive. This work demonstrates that the filamentous fungi, Aspergillus fumigatus can efficiently flocculate the unicellular cyanobacteria Synechocystis PCC 6803 and its genetically modified derivatives that have been altered to enable secretion of free fatty acids into growth media. Secreted free fatty acids are potentially used by fungal cells as a carbon source for growth and ex-novo production of lipids. For most of genetically modified strains the total lipid yields extracted from the fungal-cyanobacterial pellets were found to be higher than additive yields of lipids and total free fatty acids produced by fungal and Synechocystis components when grown in mono-cultures. The synergistic effect observed in fungal-Synechocystis associations was also found in bioremediation rates when animal husbandry wastewater was used an alternative source of nitrogen and phosphorus. Fungal assisted flocculation can complement and assist in large scale biofuel production from wild-type and genetically modified Synechocystis PCC 6803 strains by (1) efficient harvesting of cyanobacterial cells and (2) producing of high yields of lipids accumulated in fungal-cyanobacterial pellets.

On the evolution and modelling of lattice strains during the cyclic loading of TWIP steel

International Nuclear Information System (INIS)

Saleh, Ahmed A.; Pereloma, Elena V.; Clausen, Bjørn; Brown, Donald W.; Tomé, Carlos N.; Gazder, Azdiar A.

2013-01-01

The evolution of lattice strains in fully annealed Fe–24Mn–3Al–2Si–1Ni–0.06C twinning-induced plasticity (TWIP) steel is investigated via in situ neutron diffraction during cyclic (tension–compression) loading between strain limits of ±1%. The pronounced Bauschinger effect observed upon load reversal is accounted for by a combination of the intergranular residual stresses and the intragranular sources of back stress, such as dislocation pile-ups at the intersection of stacking faults. The recently modified elasto-plastic self-consistent (EPSC) model which empirically accounts for both intergranular and intragranular back stresses has been successfully used to simulate the macroscopic stress–strain response and the evolution of the lattice strains. The EPSC model captures the experimentally observed tension–compression asymmetry as it accounts for the directionality of twinning as well as Schmid factor considerations. For the strain limits used in this study, the EPSC model also predicts that the lower flow stress on reverse shear loading reported in earlier Bauschinger-type experiments on TWIP steel is a geometrical or loading path effect

Myocardial strains from 3D displacement encoded magnetic resonance imaging

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Kindberg Katarina

2012-04-01

Full Text Available Abstract Background The ability to measure and quantify myocardial motion and deformation provides a useful tool to assist in the diagnosis, prognosis and management of heart disease. The recent development of magnetic resonance imaging methods, such as harmonic phase analysis of tagging and displacement encoding with stimulated echoes (DENSE, make detailed non-invasive 3D kinematic analyses of human myocardium possible in the clinic and for research purposes. A robust analysis method is required, however. Methods We propose to estimate strain using a polynomial function which produces local models of the displacement field obtained with DENSE. Given a specific polynomial order, the model is obtained as the least squares fit of the acquired displacement field. These local models are subsequently used to produce estimates of the full strain tensor. Results The proposed method is evaluated on a numerical phantom as well as in vivo on a healthy human heart. The evaluation showed that the proposed method produced accurate results and showed low sensitivity to noise in the numerical phantom. The method was also demonstrated in vivo by assessment of the full strain tensor and to resolve transmural strain variations. Conclusions Strain estimation within a 3D myocardial volume based on polynomial functions yields accurate and robust results when validated on an analytical model. The polynomial field is capable of resolving the measured material positions from the in vivo data, and the obtained in vivo strains values agree with previously reported myocardial strains in normal human hearts.

Antimicrobial effects of zero-valent iron nanoparticles on gram-positive Bacillus strains and gram-negative Escherichia coli strains

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Yi-Huang Hsueh

2017-11-01

Full Text Available Abstract Background Zero-valent iron nanoparticles (ZVI NPs have been used extensively for the remediation of contaminated soil and groundwater. Owing to their large active surface area, they serve as strong and effective reductants. However, the ecotoxicity and bioavailability of ZVI NPs in diverse ecological media have not been evaluated in detail and most studies have focused on non-nano ZVI or Fe0. In addition, the antimicrobial properties of ZVI NPs have rarely been investigated, and the underlying mechanism of their toxicity remains unknown. Results In the present study, we demonstrate that ZVI NPs exhibited significant toxicity at 1000 ppm against two distinct gram-positive bacterial strains (Bacillus subtilis 3610 and Bacillus thuringiensis 407 but not against two gram-negative strains (Escherichia coli K12 and ATCC11634. Specifically, ZVI NPs caused at least a 4-log and 1-log reductions in cell numbers, respectively, in the two Bacillus strains, whereas no change was detected in the two E. coli strains. X-ray photoelectron spectroscopy, X-ray absorption near-edge, and extended X-ray absorption fine structure spectra confirmed that Bacillus cells exposed to ZVI NPs contained mostly Fe2O3 with some detectable FeS. This finding indicated that Fe0 nanoparticles penetrated the bacterial cells, where they were subsequently oxidized to Fe2O3 and FeS. RedoxSensor analysis and propidium iodide (PI staining showed decreased reductase activity and increased PI in both Bacillus strains treated with a high (1000 ppm concentration of ZVI NPs. Conclusion Taken together, these data show that the toxicity of ZVI NPs was derived from their oxidative properties, which may increase the levels of reactive oxygen species and lead to cell death.

Collagen-like proteins in pathogenic E. coli strains.

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Neelanjana Ghosh

Full Text Available The genome sequences of enterohaemorrhagic E. coli O157:H7 strains show multiple open-reading frames with collagen-like sequences that are absent from the common laboratory strain K-12. These putative collagens are included in prophages embedded in O157:H7 genomes. These prophages carry numerous genes related to strain virulence and have been shown to be inducible and capable of disseminating virulence factors by horizontal gene transfer. We have cloned two collagen-like proteins from E. coli O157:H7 into a laboratory strain and analysed the structure and conformation of the recombinant proteins and several of their constituting domains by a variety of spectroscopic, biophysical, and electron microscopy techniques. We show that these molecules exhibit many of the characteristics of vertebrate collagens, including trimer formation and the presence of a collagen triple helical domain. They also contain a C-terminal trimerization domain, and a trimeric α-helical coiled-coil domain with an unusual amino acid sequence almost completely lacking leucine, valine or isoleucine residues. Intriguingly, these molecules show high thermal stability, with the collagen domain being more stable than those of vertebrate fibrillar collagens, which are much longer and post-translationally modified. Under the electron microscope, collagen-like proteins from E. coli O157:H7 show a dumbbell shape, with two globular domains joined by a hinged stalk. This morphology is consistent with their likely role as trimeric phage side-tail proteins that participate in the attachment of phage particles to E. coli target cells, either directly or through assembly with other phage tail proteins. Thus, collagen-like proteins in enterohaemorrhagic E. coli genomes may have a direct role in the dissemination of virulence-related genes through infection of harmless strains by induced bacteriophages.

Temperature dependent piezoelectric response and strain-electric-field hysteresis of rare-earth modified bismuth ferrite ceramics

DEFF Research Database (Denmark)

Walker, Julian; Ursic, Hana; Bencan, Andreja

2016-01-01

with varying amounts of polar rhombohedral R3c and intermediate antipolar orthorhombic Pbam phases as a function of the RE species. During electric-field cycling at electric-fields with amplitudes of 160 kV cm-1, peak-to-peak strains of 0.23-0.27% are reached for all three compositions. However...

Immobilization induced osteopenia is strain specific in mice

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Andreas Lodberg

2015-06-01

Full Text Available Immobilization causes rapid and massive bone loss. By comparing Botulinum Toxin A (BTX-induced bone loss in mouse strains with different genetic backgrounds we investigated whether the genetic background had an influence on the severity of the osteopenia. Secondly, we investigated whether BTX had systemic effects on bone. Female mice from four inbred mouse strains (BALB/cJ, C57BL/6 J, DBA/2 J, and C3H/HeN were injected unilaterally with BTX (n = 10/group or unilaterally with saline (n = 10/group. Mice were euthanized after 21 days, and the bone properties evaluated using μCT, DXA, bone histomorphometry, and mechanical testing. BTX resulted in substantially lower trabecular bone volume fraction (BV/TV and trabecular thickness in all mouse strains. The deterioration of BV/TV was significantly greater in C57BL/6 J (−57% and DBA/2 J (−60% than in BALB/cJ (−45% and C3H/HeN (−34% mice. The loss of femoral neck fracture strength was significantly greater in C57BL/6 J (−47% and DBA/2 J (−45% than in C3H (−25% mice and likewise the loss of mid-femoral fracture strength was greater in C57BL/6 J (−17%, DBA/2 J (−12%, and BALB/cJ (−9% than in C3H/HeN (−1% mice, which were unaffected. Using high resolution μCT we found no evidence of a systemic effect on any of the microstructural parameters of the contralateral limb. Likewise, there was no evidence of a systemic effect on the bone strength in any mouse strain. We did, however, find a small systemic effect on aBMD in DBA/2 J and C3H/HeN mice. The present study shows that BTX-induced immobilization causes the greatest loss of cortical and trabecular bone in C57BL/6 J and DBA/2 J mice. A smaller loss of bone microstructure and fracture strength was seen in BALB/cJ mice, while the bone microstructure and fracture strength of C3H/HeN mice were markedly less affected. This indicates that BTX-induced loss of bone is mouse strain dependent. We found only minimal systemic

FLO11 gene length and transcriptional level affect biofilm-forming ability of wild flor strains of Saccharomyces cerevisiae.

Science.gov (United States)

Zara, Giacomo; Zara, Severino; Pinna, Claudia; Marceddu, Salvatore; Budroni, Marilena

2009-12-01

In Saccharomyces cerevisiae, FLO11 encodes an adhesin that is associated with different phenotypes, such as adherence to solid surfaces, hydrophobicity, mat and air-liquid biofilm formation. In the present study, we analysed FLO11 allelic polymorphisms and FLO11-associated phenotypes of 20 flor strains. We identified 13 alleles of different lengths, varying from 3.0 to 6.1 kb, thus demonstrating that FLO11 is highly polymorphic. Two alleles of 3.1 and 5.0 kb were cloned into strain BY4742 to compare the FLO11-associated phenotypes in the same genetic background. We show that there is a significant correlation between biofilm-forming ability and FLO11 length both in different and in the same genetic backgrounds. Moreover, we propose a multiple regression model that allows prediction of air-liquid biofilm-forming ability on the basis of transcription levels and lengths of FLO11 alleles in a population of S. cerevisiae flor strains. Considering that transcriptional differences are only partially explained by the differences in the promoter sequences, our results are consistent with the hypothesis that FLO11 transcription levels are strongly influenced by genetic background and affect biofilm-forming ability.

Gene expression profiling in the striatum of inbred mouse strains with distinct opioid-related phenotypes

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Piechota Marcin

2006-06-01

Full Text Available Abstract Background Mouse strains with a contrasting response to morphine provide a unique model for studying the genetically determined diversity of sensitivity to opioid reward, tolerance and dependence. Four inbred strains selected for this study exhibit the most distinct opioid-related phenotypes. C57BL/6J and DBA/2J mice show remarkable differences in morphine-induced antinociception, self-administration and locomotor activity. 129P3/J mice display low morphine tolerance and dependence in contrast to high sensitivity to precipitated withdrawal observed in SWR/J and C57BL/6J strains. In this study, we attempted to investigate the relationships between genetic background and basal gene expression profile in the striatum, a brain region involved in the mechanism of opioid action. Results Gene expression was studied by Affymetrix Mouse Genome 430v2.0 arrays with probes for over 39.000 transcripts. Analysis of variance with the control for false discovery rate (q Khdrbs1 and ATPase Na+/K+ alpha2 subunit (Atp1a2 with morphine self-administration and analgesic effects, respectively. Finally, the examination of transcript structure demonstrated a possible inter-strain variability of expressed mRNA forms as for example the catechol-O-methyltransferase (Comt gene. Conclusion The presented study led to the recognition of differences in the gene expression that may account for distinct phenotypes. Moreover, results indicate strong contribution of genetic background to differences in gene transcription in the mouse striatum. The genes identified in this work constitute promising candidates for further animal studies and for translational genetic studies in the field of addictive and analgesic properties of opioids.

Modifying the electronic and optical properties of carbon nanotubes

Science.gov (United States)

Kinder, Jesse M.

The intrinsic electronic and optical properties of carbon nanotubes make them promising candidates for circuit elements and LEDs in nanoscale devices. However, applied fields and interactions with the environment can modify these intrinsic properties. This dissertation is a theoretical study of perturbations to an ideal carbon nanotube. It illustrates how transport and optical properties of carbon nanotubes can be adversely affected or intentionally modified by the local environment. The dissertation is divided into three parts. Part I analyzes the effect of a transverse electric field on the single-electron energy spectrum of semiconducting carbon nanotubes. Part II analyzes the effect of the local environment on selection rules and decay pathways relevant to dark excitons. Part III is a series of 26 appendices. Two different models for a transverse electric field are introduced in Part I. The first is a uniform field perpendicular to the nanotube axis. This model suggests the field has little effect on the band gap until it exceeds a critical value that can be tuned with strain or a magnetic field. The second model is a transverse field localized to a small region along the nanotube axis. The field creates a pair of exponentially localized bound states but has no effect on the band gap for particle transport. Part II explores the physics of dark excitons in carbon nanotubes. Two model calculations illustrate the effect of the local environment on allowed optical transitions and nonradiative recombination pathways. The first model illustrates the role of inversion symmetry in the optical spectrum. Broken inversion symmetry may explain low-lying peaks in the exciton spectrum of boron nitride nanotubes and localized photoemission around impurities and interfaces in carbon nanotubes. The second model in Part II suggests that free charge carriers can mediate an efficient nonradiative decay process for dark excitons in carbon nanotubes. The appendices in Part III

Tunnel Magnetoresistance Sensors with Magnetostrictive Electrodes: Strain Sensors

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Ali Tavassolizadeh

2016-11-01

Full Text Available Magnetostrictive tunnel magnetoresistance (TMR sensors pose a bright perspective in micro- and nano-scale strain sensing technology. The behavior of TMR sensors under mechanical stress as well as their sensitivity to the applied stress depends on the magnetization configuration of magnetic tunnel junctions (MTJs with respect to the stress axis. Here, we propose a configuration resulting in an inverse effect on the tunnel resistance by tensile and compressive stresses. Numerical simulations, based on a modified Stoner–Wohlfarth (SW model, are performed in order to understand the magnetization reversal of the sense layer and to find out the optimum bias magnetic field required for high strain sensitivity. At a bias field of −3.2 kA/m under a 0.2 × 10 - 3 strain, gauge factors of 2294 and −311 are calculated under tensile and compressive stresses, respectively. Modeling results are investigated experimentally on a round junction with a diameter of 30 ± 0.2 μ m using a four-point bending apparatus. The measured field and strain loops exhibit nearly the same trends as the calculated ones. Also, the gauge factors are in the same range. The junction exhibits gauge factors of 2150 ± 30 and −260 for tensile and compressive stresses, respectively, under a −3.2 kA/m bias magnetic field. The agreement of the experimental and modeling results approves the proposed configuration for high sensitivity and ability to detect both tensile and compressive stresses by a single TMR sensor.

Strain Rate Dependent Ductile-to-Brittle Transition of Graphite Platelet Reinforced Vinyl Ester Nanocomposites

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Brahmananda Pramanik

2014-01-01

Full Text Available In previous research, the fractal dimensions of fractured surfaces of vinyl ester based nanocomposites were estimated applying classical method on 3D digital microscopic images. The fracture energy and fracture toughness were obtained from fractal dimensions. A noteworthy observation, the strain rate dependent ductile-to-brittle transition of vinyl ester based nanocomposites, is reinvestigated in the current study. The candidate materials of xGnP (exfoliated graphite nanoplatelets reinforced and with additional CTBN (Carboxyl Terminated Butadiene Nitrile toughened vinyl ester based nanocomposites that are subjected to both quasi-static and high strain rate indirect tensile load using the traditional Brazilian test method. High-strain rate indirect tensile testing is performed with a modified Split-Hopkinson Pressure Bar (SHPB. Pristine vinyl ester shows ductile deformation under quasi-static loading and brittle failure when subjected to high-strain rate loading. This observation reconfirms the previous research findings on strain rate dependent ductile-to-brittle transition of this material system. Investigation of both quasi-static and dynamic indirect tensile test responses show the strain rate effect on the tensile strength and energy absorbing capacity of the candidate materials. Contribution of nanoreinforcement to the tensile properties is reported in this paper.

High strain rate tensile behavior of Al-4.8Cu-1.2Mg alloy

International Nuclear Information System (INIS)

Bobbili, Ravindranadh; Paman, Ashish; Madhu, V.

2016-01-01

The purpose of the current study is to perform quasi static and high strain rate tensile tests on Al-4.8Cu-1.2Mg alloy under different strain rates ranging from 0.01–3500/s and also at temperatures of 25,100, 200 and 300 °C. The combined effect of strain rate, temperature and stress triaxiality on the material behavior is studied by testing both smooth and notched specimens. Johnson–Cook (J–C) constitutive and fracture models are established based on high strain rate tensile data obtained from Split hopkinson tension bar (SHTB) and quasi-static tests. By modifying the strain hardening and strain rate hardening terms in the Johnson–Cook (J–C) constitutive model, a new J–C constitutive model of Al-4.8Cu-1.2Mg alloy was obtained. The improved Johnson–Cook constitutive model matched the experiment results very well. With the Johnson–Cook constitutive and fracture models, numerical simulations of tensile tests at different conditions for Al-4.8Cu-1.2Mg alloy were conducted. Numerical simulations are performed using a non-linear explicit finite element code autodyn. Good agreement is obtained between the numerical simulation results and the experiment results. The fracture surfaces of specimens tested under various strain rates and temperatures were studied under scanning electron microscopy (SEM).

A model based on soil structural aspects describing the fate of genetically modified bacteria in soil

NARCIS (Netherlands)

Hoeven, van der N.; Elsas, van J.D.; Heijnen, C.E.

1996-01-01

A computer simulation model was developed which describes growth and competition of bacteria in the soil environment. In the model, soil was assumed to contain millions of pores of a few different size classes. An introduced bacterial strain, e.g. a genetically modified micro-organism (GEMMO), was

Hemizygous Le-Cre Transgenic Mice Have Severe Eye Abnormalities on Some Genetic Backgrounds in the Absence of LoxP Sites

Science.gov (United States)

Dorà, Natalie J.; Collinson, J. Martin; Hill, Robert E.; West, John D.

2014-01-01

Eye phenotypes were investigated in Le-CreTg/−; Pax6fl/+ mice, which were expected to show tissue-specific reduction of Pax6 in surface ectoderm derivatives. To provide a better comparison with our previous studies of Pax6+/− eye phenotypes, hemizygous Le-CreTg/− and heterozygous Pax6fl/+mice were crossed onto the CBA/Ca genetic background. After the Le-Cre transgene had been backcrossed to CBA/Ca for seven generations, significant eye abnormalities occurred in some hemizygous Le-CreTg/−; Pax6+/+ controls (without a floxed Pax6fl allele) as well as experimental Le-CreTg/−; Pax6fl/+ mice. However, no abnormalities were seen in Le-Cre−/−; Pax6fl/+ or Le-Cre−/−; Pax6+/+ controls (without the Le-Cre transgene). The severity and frequency of the eye abnormalities in Le-CreTg/−; Pax6+/+ control mice diminished after backcrossing Le-CreTg/− mice to the original FVB/N strain for two generations, showing that the effect was reversible. This genetic background effect suggests that the eye abnormalities are a consequence of an interaction between the Le-Cre transgene and alleles of unknown modifier genes present in certain genetic backgrounds. The abnormalities were also ameliorated by introducing additional Pax6 gene copies on a CBA/Ca background, suggesting involvement of Pax6 depletion in Le-CreTg/−; Pax6+/+ mice rather than direct action of Cre recombinase on cryptic pseudo-loxP sites. One possibility is that expression of Cre recombinase from the Pax6-Le regulatory sequences in the Le-Cre transgene depletes cofactors required for endogenous Pax6 gene expression. Our observation that eye abnormalities can occur in hemizygous Le-CreTg/−; Pax6+/+ mice, in the absence of a floxed allele, demonstrates the importance of including all the relevant genetic controls in Cre-loxP experiments. PMID:25272013

Isolation and characterization of a novel native Bacillus thuringiensis strain BRC-HZM2 capable of degrading chlorpyrifos.

Science.gov (United States)

Wu, Songqing; Peng, Yan; Huang, Zhangmin; Huang, Zhipeng; Xu, Lei; Ivan, Gelbič; Guan, Xiong; Zhang, Lingling; Zou, Shuangquan

2015-03-01

Studies were carried out to isolate chlorpyrifos degrading Bacillus thuringiensis (Bt) strains from chlorpyrifos-contaminated samples. Six Bt strains (isolation rate 2.7%) were isolated by modified sodium acetate antibiotic heat treatment, and one novel strain (BRC-HZM2) was selected for further analysis. Phenotype and phylogeny analysis of this strain was conducted on the basis of biochemical reactions, antibiotic sensitivity, 16s rRNA genes, plasmid profile, insecticidal crystal protein profiles, and PCR-RFLP for cry and cyt genes. The degradation rate of chlorpyrifos in liquid culture was estimated during 48 h of incubation for the isolate BRC-HZM2. More than 50% of the initial chlorpyrifos concentration degraded within 12 h, 88.9% after 48 h. These results highlight the potential of the Bt strain for biological control and the bioremediation of environments contaminated with chlorpyrifos. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Comparative Study on Johnson Cook, Modified Zerilli-Armstrong and Arrhenius-Type Constitutive Models to Predict High-Temperature Flow Behavior of Ti-6Al-4V Alloy in α + β Phase

Science.gov (United States)

Cai, Jun; Wang, Kuaishe; Han, Yingying

2016-03-01

True stress and true strain values obtained from isothermal compression tests over a wide temperature range from 1,073 to 1,323 K and a strain rate range from 0.001 to 1 s-1 were employed to establish the constitutive equations based on Johnson Cook, modified Zerilli-Armstrong (ZA) and strain-compensated Arrhenius-type models, respectively, to predict the high-temperature flow behavior of Ti-6Al-4V alloy in α + β phase. Furthermore, a comparative study has been made on the capability of the three models to represent the elevated temperature flow behavior of Ti-6Al-4V alloy. Suitability of the three models was evaluated by comparing both the correlation coefficient R and the average absolute relative error (AARE). The results showed that the Johnson Cook model is inadequate to provide good description of flow behavior of Ti-6Al-4V alloy in α + β phase domain, while the predicted values of modified ZA model and the strain-compensated Arrhenius-type model could agree well with the experimental values except under some deformation conditions. Meanwhile, the modified ZA model could track the deformation behavior more accurately than other model throughout the entire temperature and strain rate range.

Ge nanobelts with high compressive strain fabricated by secondary oxidation of self-assembly SiGe rings

DEFF Research Database (Denmark)

Lu, Weifang; Li, Cheng; Lin, Guangyang

2015-01-01

Curled Ge nanobelts were fabricated by secondary oxidation of self-assembly SiGe rings, which were exfoliated from the SiGe stripes on the insulator. The Ge-rich SiGe stripes on insulator were formed by hololithography and modified Ge condensation processes of Si0.82Ge0.18 on SOI substrate. Ge...... nanobelts under a residual compressive strain of 2% were achieved, and the strain should be higher before partly releasing through bulge islands and breakage of the curled Ge nanobelts during the secondary oxidation process. The primary factor leading to compressive strain is thermal shrinkage of Ge...... nanobelts, which extrudes to Ge nanobelts in radial and tangent directions during the cooling process. This technique is promising for application in high-mobility Ge nano-scale transistors...

P1-18: The Effect of Background Music on Working Memory

OpenAIRE

Ding-Hao Liu; Yi-Fang Shih; Pei-Jin Yang; Mei-Nian Lu; Yi-shan Su; Shiiau-hua Liu

2012-01-01

Many studies do visual working memory research under sundry sound conditions (Alley & Greene, 2008 Current Psychology 27 277–289; Iwanaga & Ito, 2002 Perceptual Motor Skills 94 1251–1258; Pring & Walker, 1994 Current Psychology 13 165–171). In order to understand more about background music, we modified previous studies to examine how the performance of working memory is affected by four different music conditions. Participants were randomly assigned into two groups to listen to two different...

Symmetry analysis of strain, electric and magnetic fields in the Bi2Se3-class of topological insulators

DEFF Research Database (Denmark)

Brems, Mathias Rosdahl; Paaske, Jens; Lunde, Anders Mathias

2018-01-01

velocity. The spin-momentum locking of strained Bi2Se3 is shown to be modified. Hence, strain control can be used to manipulate the spin degree of freedom via the spin–orbit coupling. We show that for a thin film of Bi2Se3 the SS band gap induced by coupling between the opposite surfaces changes opposite...... to the bulk band gap under strain. Tuning the SS band gap by strain, gives new possibilities for the experimental investigation of the thickness dependent gap and optimization of optical properties relevant for, e.g., photodetector and energy harvesting applications. We finally derive analytical expressions...... analytically the effects of strain on the electronic structure of Bi2Se3. For the most experimentally relevant surface termination we analytically derive the surface state (SS) spectrum, revealing an anisotropic Dirac cone with elliptical constant energy contours giving rise to a direction-dependent group...

Evaluation of the strain rate effects on environmental fatigue life of CF8M cast stainless steel

International Nuclear Information System (INIS)

Jeong, Ill Seok; Ha, Gak Hyun; Jeon, Hyun Ik

2009-01-01

The environmental fatigue life of CF8M cast stainless steel is influenced by mechanical, environmental and metallurgical parameters, such as strain rate, strain amplitude, temperature, dissolved oxygen concentration, water flow rate and so on. In an actual plant, the mechanical and environmental parameters are changing during the plant operation. Therefore, the effect of such mechanical and environmental parameter changes on fatigue life evaluation have to be studied. Low cycle fatigue life of structural materials diminishes remarkably as functions of various parameters in high temperature and high pressure environments. Such reduction can be estimated by the fatigue life reduction factor(F en ). In this study, fatigue tests were performed under changing conditions of strain amplitude, strain rate. Fatigue life was measured in terms of the number of cycles with the variation of strain amplitudes at 0.004 %/s strain rate, and the fatigue life correction factor was evaluated according to the equation modified by U. S. Nuclear Regulatory Commission(U.S.NRC) and Japanese Environmental Fatigue Tests committee (JEFT).

Impact of Saccharomyces cerevisiae Strains on Health-Promoting Compounds in Wine

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Simona Guerrini

2018-04-01

Full Text Available Moderate wine consumption is associated with human health benefits (reduction of cardiovascular risk and neurodegenerative diseases, decrease of onset of certain cancers attributed to a series of bioactive compounds, mainly polyphenols, with antioxidant power capable of counteracting the negative action of free radicals. Polyphenols are naturally present in the grapes, but an additional amount originates during winemaking. The aim of this work was to assess the ability of four commercial and two indigenous Saccharomyces cerevisiae strains to produce bioactive compounds (tyrosol, hydroxytyrosol, tryptophol, melatonin and glutathione during alcoholic fermentation. In order to exclude the fraction of antioxidant compounds naturally occurring in grapes, the strains were inoculated in a synthetic must. At the end of fermentation the bioactive compounds were analysed by High-Performance Liquid Chromatography, while antioxidant activity was measured by 2,2-diphenyl-1-picrylhydrazyl (DPPH assay. Moreover, freeze-dried samples, originating from the experimental wines, were used to perform ex-vivo assays on cultured cells (RAW 264.7 murine macrophages with the aim to evaluate their antioxidant and anti-inflammatory activities. The results indicated that the production of the considered bioactive compounds is a strain-specific property; therefore, the different yeast strains utilized during fermentation have different capabilities to modify the antioxidant and anti-inflammatory properties of the wine.

What does a modified-Fibonacci dose-escalation actually correspond to?

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Penel Nicolas

2012-07-01

Full Text Available Abstract Background In most phase I oncology trials, it is often stated that the dose increments follow a “modified-Fibonacci sequence”. This term, however, is vague. Methods To better characterize this sequence, we reviewed 81 phase I trials based on this concept. Results Out of 198 phase I oncology trials, 81 (41% are based on modified-Fibonacci series. Actual incremental ratios varied in a large range from 0.80 to 2.08. The median of actual increments was about 2.00, 1.50, 1.33, 1.33, 1.33, 1.33, 1.30, 1.35…. The “modified Fibonacci-sequence” gathers heterogeneous variation of the genuine sequence, which does not tend to a constant number at higher dose-levels. Conclusion This confusing term should be avoided.

Acrolein inhalation causes myocardial strain delay and decreased cardiac performance as detected by high-frequency echocardiography in mice

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Acrolein, an unsaturated aldehyde found in air pollution, impairs Ca2+ flux and contraction in cardiomyocytes in vitro. To better define direct and delayed functional cardiac effects, we hypothesized that a single exposure to acrolein would modify myocardial strain and performanc...

Is there a link between the lipopolysaccharide of Helicobacter pylori gastric MALT lymphoma associated strains and lymphoma pathogenesis?

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Philippe Lehours

Full Text Available The aim of this study was to investigate the Lewis antigen expression in Helicobacter pylori gastric MALT lymphoma associated strains in comparison to chronic gastritis only strains. Forty MALT strains (19 cagPAI (- and 21 cagPAI (+ and 39 cagPAI frequency-matched gastritis strains (17 cagPAI (- and 22 cagPAI (+ were included in this study. The lipopolyssacharide for each strain was extracted using a hot phenol method and the expression of Le(x and Le(y were investigated using Western Blot. The data were analyzed according to the strains' cagPAI status and vacA genotype. Le(x was identified in 21 (52.5% MALT strains and 29 (74.3% gastritis strains. Le(y was identified in 30 (75% MALT strains and 31 (79.5% gastritis strains. There was an association between cagPAI positivity and Le(x expression among MALT strains (p<0.0001, but not in gastritis strains (p = 0.64. Among cagPAI (- strains, isolates expressing solely Le(y were associated with MALT with an odds ratio of 64.2 (95% CI 4.9-841.0 when compared to strains expressing both Le(x and Le(y. vacA genotypes did not modify the association between Lewis antigen expression and disease status. In conclusion, cagPAI (- MALT strains have a particular Lewis antigen profile which could represent an adaptive mechanism to the host response or participate in MALT lymphomagenesis.

Cocaine locomotor activation, sensitization and place preference in six inbred strains of mice

Science.gov (United States)

2011-01-01

Background The expanding set of genomics tools available for inbred mouse strains has renewed interest in phenotyping larger sets of strains. The present study aims to explore phenotypic variability among six commonly-used inbred mouse strains to both the rewarding and locomotor stimulating effects of cocaine in a place conditioning task, including several strains or substrains that have not yet been characterized for some or all of these behaviors. Methods C57BL/6J (B6), BALB/cJ (BALB), C3H/HeJ (C3H), DBA/2J (D2), FVB/NJ (FVB) and 129S1/SvImJ (129) mice were tested for conditioned place preference to 20 mg/kg cocaine. Results Place preference was observed in most strains with the exception of D2 and 129. All strains showed a marked increase in locomotor activity in response to cocaine. In BALB mice, however, locomotor activation was context-dependent. Locomotor sensitization to repeated exposure to cocaine was most significant in 129 and D2 mice but was absent in FVB mice. Conclusions Genetic correlations suggest that no significant correlation between conditioned place preference, acute locomotor activation, and locomotor sensitization exists among these strains indicating that separate mechanisms underlie the psychomotor and rewarding effects of cocaine. PMID:21806802

Physics of strained quantum well lasers

CERN Document Server

Loehr, John P

1998-01-01

When this publisher offered me the opportunity to \\\\Tite a book, some six years ago, I did not hesitate to say yes. I had just spent the last four years of graduate school struggling to understand the physics of strained quantum well lasers, and it seemed to me the whole experience was much more difficult that it should have been. For although many of the results I needed were easy to locate, the underlying physical premises and intervening steps were not. If only I had a book providing the derivations, I could have absorbed them and gone on my way. Such a book lies before you. It provides a unified and self-contained descrip­ tion of the essential physics of strained quantum well lasers, starting from first principles whenever feasible. The presentation I have chosen requires only the standard introductory background in quantum mechanics, solid state physics, and electromagnetics expected of entering graduate students in physics or elec­ trical engineering. A single undergraduate course in each of these su...

Experiment to measure the effects of biaxial strain on the critical current of NbTi superconductor

International Nuclear Information System (INIS)

Froelich, K.J.

1975-01-01

Twisted multifilament, copper-clad NbTi superconductors have been axially and biaxially strained at 4.2K with a 7.5T background field. A simply-constructed cryogenic loading frame was built and used to strain the conductor. Results on 1.27 mm x 3.13 mm conductor have shown that degradation of less than .3 percent of critical current occurred when the wire was biaxially strained to +3260 μepsilon in the axial direction and -1875 μepsilon in the transverse direction. Degradation approaches 3 percent of critical current at approximately 6000 μepsilon in the axial direction only

Effect of straining on diaphragmatic crura with identification of the straining-crural reflex. The "reflex theory" in gastroesophageal competence

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El Sibai Olfat

2004-09-01

Full Text Available Abstract Background The role of the crural diaphragm during increased intra-abdominal pressure is not exactly known. We investigated the hypothesis that the crural diaphragm undergoes reflex phasic contraction on elevation of the intra-abdominal pressure with a resulting increase of the lower esophageal pressure and prevention of gastro-esophageal reflux. Methods The esophageal pressure and crural diaphragm electromyographic responses to straining were recorded in 16 subjects (10 men, 6 women, age 36.6 ± 11.2 SD years during abdominal hernia repair. The electromyogram of crural diaphragm was recorded by needle electrode inserted into the crural diaphragm, and the lower esophageal pressure by a saline-perfused catheter. The study was repeated after crural anesthetization and after crural infiltration with saline. Results The crural diaphragm exhibited resting electromyographic activity which showed a significant increase on sudden (coughing, p Conclusions Straining effected an increase of the electromyographic activity of the crural diaphragm and of the lower esophageal pressure. This effect is suggested to be reflex in nature and to be mediated through the "straining-crural reflex". The crural diaphragm seems to play a role in the lower esophageal competence mechanism. Further studies are required to assess the clinical significance of the current results in gastro-esophageal reflux disease and hiatus hernia.

Genetic diversity among major endemic strains of Leptospira interrogans in China

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Zhang Zhi-Ming

2007-07-01

Full Text Available Abstract Background Leptospirosis is a world-widely distributed zoonosis. Humans become infected via exposure to pathogenic Leptospira spp. from contaminated water or soil. The availability of genomic sequences of Leptospira interrogans serovar Lai and serovar Copenhageni opened up opportunities to identify genetic diversity among different pathogenic strains of L. interrogans representing various kinds of serotypes (serogroups and serovars. Results Comparative genomic hybridization (CGH analysis was used to compare the gene content of L. interrogans serovar Lai strain Lai with that of other 10 L. interrogans strains prevailed in China and one identified from Brazil using a microarray spotted with 3,528 protein coding sequences (CDSs of strain Lai. The cutoff ratio of sample/reference (S/R hybridization for detecting the absence of genes from one tested strain was set by comparing the ratio of S/R hybridization and the in silico sequence similarities of strain Lai and serovar Copenhageni strain Fiocruz L1-130. Among the 11 strains tested, 275 CDSs were found absent from at least one strain. The common backbone of the L. interrogans genome was estimated to contain about 2,917 CDSs. The genes encoding fundamental cellular functions such as translation, energy production and conversion were conserved. While strain-specific genes include those that encode proteins related to either cell surface structures or carbohydrate transport and metabolism. We also found two genomic islands (GIs in strain Lai containing genes divergently absent in other strains. Because genes encoding proteins with potential pathogenic functions are located within GIs, these elements might contribute to the variations in disease manifestation. Differences in genes involved in O-antigen biosynthesis were also identified for strains belonging to different serogroups, which offers an opportunity for future development of genomic typing tools for serological classification

Modifiable lifestyle factors are associated with lower pain levels in adults with knee osteoarthritis

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A Erin Connelly

2015-01-01

Full Text Available BACKGROUND: With no cure or effective treatments for osteoarthritis (OA, the need to identify modifiable factors to decrease pain and increase physical function is well recognized.

Buckling induced by cyclic straining: Analysis of simple models

International Nuclear Information System (INIS)

Devos, J.; Gontier, C.; Hoffmann, A.

1983-01-01

Progressive buckling of a structure may occur under imposed loads below the critical value in cases where progressive distortion due to cyclic straining is possible. This interaction between ratchetting and buckling is usually not taken into account in design rules, such as the ASME rules. This paper presents the complete analysis of two simple cases and gives rules established on this basis. The first model is a modified version of SHANLEY's two bars; it is submitted to a constant axial compressive force F and a variable thermal stress Q. It simulates a compressed clamped-clamped beam subjected to a variable through-thickness thermal gradient. The second model is a refined version of the first taking into account strain-hardening of the deformable sections. One finds that progressive buckling is possible only if the applied force F is greater than SHANLEY's critical load and tangent moduli of the moment-curvature law, respectively. (orig./GL)

Quantitative analysis of left ventricular strain using cardiac computed tomography

Energy Technology Data Exchange (ETDEWEB)

Buss, Sebastian J., E-mail: sebastian.buss@med.uni-heidelberg.de [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany); Schulz, Felix; Mereles, Derliz [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany); Hosch, Waldemar [Department of Diagnostic and Interventional Radiology, University of Heidelberg, 69120 Heidelberg (Germany); Galuschky, Christian; Schummers, Georg; Stapf, Daniel [TomTec Imaging Systems GmbH, Munich (Germany); Hofmann, Nina; Giannitsis, Evangelos; Hardt, Stefan E. [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany); Kauczor, Hans-Ulrich [Department of Diagnostic and Interventional Radiology, University of Heidelberg, 69120 Heidelberg (Germany); Katus, Hugo A.; Korosoglou, Grigorios [Department of Cardiology, University of Heidelberg, 69120 Heidelberg (Germany)

2014-03-15

Objectives: To investigate whether cardiac computed tomography (CCT) can determine left ventricular (LV) radial, circumferential and longitudinal myocardial deformation in comparison to two-dimensional echocardiography in patients with congestive heart failure. Background: Echocardiography allows for accurate assessment of strain with high temporal resolution. A reduced strain is associated with a poor prognosis in cardiomyopathies. However, strain imaging is limited in patients with poor echogenic windows, so that, in selected cases, tomographic imaging techniques may be preferable for the evaluation of myocardial deformation. Methods: Consecutive patients (n = 27) with congestive heart failure who underwent a clinically indicated ECG-gated contrast-enhanced 64-slice dual-source CCT for the evaluation of the cardiac veins prior to cardiac resynchronization therapy (CRT) were included. All patients underwent additional echocardiography. LV radial, circumferential and longitudinal strain and strain rates were analyzed in identical midventricular short axis, 4-, 2- and 3-chamber views for both modalities using the same prototype software algorithm (feature tracking). Time for analysis was assessed for both modalities. Results: Close correlations were observed for both techniques regarding global strain (r = 0.93, r = 0.87 and r = 0.84 for radial, circumferential and longitudinal strain, respectively, p < 0.001 for all). Similar trends were observed for regional radial, longitudinal and circumferential strain (r = 0.88, r = 0.84 and r = 0.94, respectively, p < 0.001 for all). The number of non-diagnostic myocardial segments was significantly higher with echocardiography than with CCT (9.6% versus 1.9%, p < 0.001). In addition, the required time for complete quantitative strain analysis was significantly shorter for CCT compared to echocardiography (877 ± 119 s per patient versus 1105 ± 258 s per patient, p < 0.001). Conclusion: Quantitative assessment of LV strain

Evaluation of the mechanical properties of Niobium modified cast AISI H 13 hot work tool steel

International Nuclear Information System (INIS)

Noorian, A.; Kheirandish, Sh.; Saghafian, H.

2010-01-01

In this research, the effects of partially replacing of vanadium and molybdenum with niobium on the mechanical properties of AISIH 13 hot-work tool steel have been studied. Cast samples made of the modified new steel were homogenized and austenitized at different conditions, followed by tempering at the specified temperature ranges. Hardness, red hardness, three point bending test and Charpy impact test were carried out to evaluate the mechanical properties together with characterizing the microstructure of the modified steel using scanning electron microscope. The results show that niobium addition modifies the cast structure of Nb-alloyed steel, and increases its maximum hardness. It was found that bending strength; bending strain, impact strength, and red hardness of the modified cast steel are also higher than those of the cast H13 steel, and lower than those of the wrought H13 steel.

Technological characterization and survival of the exopolysaccharide-producing strain Lactobacillus delbrueckii subsp. lactis 193 and its bile-resistant derivative 193+ in simulated gastric and intestinal juices.

Science.gov (United States)

Burns, Patricia; Vinderola, Gabriel; Reinheimer, Jorge; Cuesta, Isabel; de Los Reyes-Gavilán, Clara G; Ruas-Madiedo, Patricia

2011-08-01

The capacity of lactic acid bacteria to produce exopolysaccharides (EPS) conferring microorganisms a ropy phenotype could be an interesting feature from a technological point of view. Progressive adaptation to bile salts might render some lactobacilli able to overcome physiological gut barriers but could also modify functional properties of the strain, including the production of EPS. In this work some technological properties and the survival ability in simulated gastrointestinal conditions of Lactobacillus delbrueckii subsp. lactis 193, and Lb. delbrueckii subsp. lactis 193+, a strain with stable bile-resistant phenotype derived thereof, were characterized in milk in order to know whether the acquisition of resistance to bile could modify some characteristics of the microorganism. Both strains were able to grow and acidify milk similarly; however the production of ethanol increased at the expense of the aroma compound acetaldehyde in milk fermented by the strain 193+, with respect to milk fermented by the strain 193. Both microorganisms produced a heteropolysaccharide composed of glucose and galactose, and were able to increase the viscosity of fermented milks. In spite of the higher production yield of EPS by the bile-resistant strain 193+, it displayed a lower ability to increase viscosity than Lb. delbrueckii subsp. lactis 193. Milk increased survival in simulated gastric juice; the presence of bile improved adhesion to the intestinal cell line HT29-MTX in both strains. However, the acquisition of a stable resistance phenotype did not improve survival in simulated gastric and intestinal conditions or the adhesion to the intestinal cell line HT29-MTX. Thus, Lb. delbrueckii subsp. lactis 193 presents suitable technological properties for the manufacture of fermented dairy products; the acquisition of a stable bile-resistant phenotype modified some properties of the microorganism. This suggests that the possible use of bile-resistant derivative strains should be

Comparative proteomic analysis of pathogenic and non-pathogenic strains from the swine pathogen Mycoplasma hyopneumoniae

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Klein Cátia S

2009-12-01

Full Text Available Abstract Background Mycoplasma hyopneumoniae is a highly infectious swine pathogen and is the causative agent of enzootic pneumonia (EP. Following the previous report of a proteomic survey of the pathogenic 7448 strain of swine pathogen, Mycoplasma hyopneumoniae, we performed comparative protein profiling of three M. hyopneumoniae strains, namely the non-pathogenic J strain and the two pathogenic strains 7448 and 7422. Results In 2DE comparisons, we were able to identify differences in expression levels for 67 proteins, including the overexpression of some cytoadherence-related proteins only in the pathogenic strains. 2DE immunoblot analyses allowed the identification of differential proteolytic cleavage patterns of the P97 adhesin in the three strains. For more comprehensive protein profiling, an LC-MS/MS strategy was used. Overall, 35% of the M. hyopneumoniae genome coding capacity was covered. Partially overlapping profiles of identified proteins were observed in the strains with 81 proteins identified only in one strain and 54 proteins identified in two strains. Abundance analysis of proteins detected in more than one strain demonstrates the relative overexpression of 64 proteins, including the P97 adhesin in the pathogenic strains. Conclusions Our results indicate the physiological differences between the non-pathogenic strain, with its non-infective proliferate lifestyle, and the pathogenic strains, with its constitutive expression of adhesins, which would render the bacterium competent for adhesion and infection prior to host contact.

Linezolid-Dependent Function and Structure Adaptation of Ribosomes in a Staphylococcus epidermidis Strain Exhibiting Linezolid Dependence

Science.gov (United States)

Kokkori, Sofia; Apostolidi, Maria; Tsakris, Athanassios; Pournaras, Spyros

2014-01-01

Linezolid-dependent growth was recently reported in Staphylococcus epidermidis clinical strains carrying mutations associated with linezolid resistance. To investigate this unexpected behavior at the molecular level, we isolated active ribosomes from one of the linezolid-dependent strains and we compared them with ribosomes isolated from a wild-type strain. Both strains were grown in the absence and presence of linezolid. Detailed biochemical and structural analyses revealed essential differences in the function and structure of isolated ribosomes which were assembled in the presence of linezolid. The catalytic activity of peptidyltransferase was found to be significantly higher in the ribosomes derived from the linezolid-dependent strain. Interestingly, the same ribosomes exhibited an abnormal ribosomal subunit dissociation profile on a sucrose gradient in the absence of linezolid, but the profile was restored after treatment of the ribosomes with an excess of the antibiotic. Our study suggests that linezolid most likely modified the ribosomal assembly procedure, leading to a new functional ribosomal population active only in the presence of linezolid. Therefore, the higher growth rate of the partially linezolid-dependent strains could be attributed to the functional and structural adaptations of ribosomes to linezolid. PMID:24890589

Magnetic resonance imaging detects significant sex differences in human myocardial strain

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Reynolds Lina M

2011-08-01

Full Text Available Abstract Background The pathophysiology responsible for the significant outcome disparities between men and women with cardiac disease is largely unknown. Further investigation into basic cardiac physiological differences between the sexes is needed. This study utilized magnetic resonance imaging (MRI-based multiparametric strain analysis to search for sex-based differences in regional myocardial contractile function. Methods End-systolic strain (circumferential, longitudinal, and radial was interpolated from MRI-based radiofrequency tissue tagging grid point displacements in each of 60 normal adult volunteers (32 females. Results The average global left ventricular (LV strain among normal female volunteers (n = 32 was significantly larger in absolute value (functionally better than in normal male volunteers (n = 28 in both the circumferential direction (Male/Female = -0.19 ± 0.02 vs. -0.21 ± 0.02; p = 0.025 and longitudinal direction (Male/Female = -0.14 ± 0.03 vs. -0.16 ± 0.02; p = 0.007. Conclusions The finding of significantly larger circumferential and longitudinal LV strain among normal female volunteers suggests that baseline contractile differences between the sexes may contribute to the well-recognized divergence in cardiovascular disease outcomes. Further work is needed in order to determine the pathologic changes that occur in LV strain between women and men with the onset of cardiovascular disease.

A Food-Grade Cloning System for Industrial Strains of Lactococcus lactis

Science.gov (United States)

Sørensen, Kim I.; Larsen, Rasmus; Kibenich, Annette; Junge, Mette P.; Johansen, Eric

2000-01-01

We have previously reported the construction of a food-grade cloning vector for Lactococcus using the ochre suppressor, supB, as the selective marker. This vector, pFG1, causes only a slight growth inhibition in the laboratory strain MG1363 but is unstable in the industrial strains tested. As supB suppresses both amber and ochre stop codons, which are present in 82% of all known lactococcal genes, this undesirable finding may result from the accumulation of elongated mistranslated polypeptides. Here, we report the development of a new food-grade cloning vector, pFG200, which is suitable for overexpressing a variety of genes in industrial strains of Lactococcus lactis. The vector uses an amber suppressor, supD, as selectable marker and consists entirely of Lactococcus DNA, with the exception of a small polylinker region. Using suppressible pyrimidine auxotrophs, selection and maintenance are efficient in any pyrimidine-free medium including milk. Importantly, the presence of this vector in a variety of industrial strains has no significant effect on the growth rate or the rate of acidification in milk, making this an ideal system for food-grade modification of industrially relevant L. lactis strains. The usefulness of this system is demonstrated by overexpressing the pepN gene in a number of industrial backgrounds. PMID:10742196

Two-dimensional global longitudinal strain is superior to left ventricular ejection fraction in prediction of outcome in patients with left-sided infective endocarditis

DEFF Research Database (Denmark)

Lauridsen, Trine Kiilerich; Alhede, Christina; Crowley, Anna Lisa

2018-01-01

BACKGROUND: Impaired cardiac function is the main predictor of poor outcome in infective endocarditis (IE). Global longitudinal strain (GLS) derived from two-dimensional strain echocardiography has proven superior in prediction of long-term outcome as compared to left ventricular ejection fraction...

Evolution of phase structure and giant strain at low driving fields in Bi-based lead-free incipient piezoelectrics

International Nuclear Information System (INIS)

Maqbool, Adnan; Hussain, Ali; Malik, Rizwan Ahmed; Rahman, Jamil Ur; Zaman, Arif; Song, Tae Kwon; Kim, Won-Jeong; Kim, Myong-Ho

2015-01-01

Graphical abstract: - Highlights: • Nb-doped BNBT–SZ ceramics were prepared by conventional solid state method. • A giant normalized strain of 825 pm/V at 4 kV/mm was achieved. • A large strain of 0.20% triggered at a relatively low field of 3 kV/mm. • Highest strain obtained in BNT-based ceramics at such a low driving field. • Ferroelectric to ergodic-relaxor phase transition occurred with Nb-doping. - Abstract: Lead-free 0.99[(Bi 0.5 Na 0.5 ) 0.935 Ba 0.065 Ti (1–x) Nb x O 3 ]–0.01SrZrO 3 (BNBTNb100x–SZ, with Nb100x = 0–1) ceramics were prepared by the conventional mixed oxide route. X-ray diffraction and Raman scattering was utilized for the structural evolution of Nb-modified BNBT–SZ ceramics at average and short-scale localized structure. Temperature dependent dielectric properties showed ferroelectric–ergodic relaxor (FE–ER) transition in Nb-modified BNBT–SZ ceramics by producing a significant disruption of the long-range FE order. A giant normalized strain of 825 pm/V at 4 kV/mm was achieved at Nb1.0. Interestingly, at a relatively low applied field of 3 kV/mm, the Nb0.75 sample displayed a large electric field-induced strain (EFIS) response of 0.20%, which is highest value obtained in non-textured lead-free BNT-based ceramics at such low driving field. The structural distortion induced by doping and electric poling is correlated with the dielectric, ferroelectric and EFIS response, and the evolution of giant strain was ascribed to reversible field induced phase transition from ER–FE phase

Modeling the growth dynamics of multiple Escherichia coli strains in the pig intestine following intramuscular ampicillin treatment

DEFF Research Database (Denmark)

Ahmad, Amais; Zachariasen, Camilla; Christiansen, Lasse Engbo

2016-01-01

using a mathematical model to simulate the competitive growth of E. coli strains in a pig intestine under specified plasma concentration profiles of ampicillin. Results : In vitro growth results demonstrated that the resistant strains did not carry a fitness cost for their resistance, and that the most...... with ampicillin resistance in E. coli. Besides dosing factors, epidemiological factors (such as number of competing strains and bacterial excretion) influenced resistance development and need to be considered further in relation to optimal treatment strategies. The modeling approach used in the study is generic......Background : This study evaluated how dosing regimen for intramuscularly-administered ampicillin, composition of Escherichia coli strains with regard to ampicillin susceptibility, and excretion of bacteria from the intestine affected the level of resistance among Escherichia coli strains...

Dependence of the optical conductivity on the uniaxial and biaxial strains in black phosphorene

Science.gov (United States)

Yang, C. H.; Zhang, J. Y.; Wang, G. X.; Zhang, C.

2018-06-01

By using the Kubo formula, the optical conductivity of strained black phosphorene was studied. The anisotropic band dispersion gives rise to an orientation dependent optical conductivity. The energy gap can be tuned by the uniaxial and biaxial strains which can be observed from the interband optical conductivity polarized along the armchair (x ) direction. The preferential conducting direction is along the x direction. The dependence of the intraband optical conductivity along the zigzag (y ) direction on the Fermi energy and strain exhibits increasing or decreasing monotonously. However, along the x direction this dependence is complicated which originates from the carriers' inverse-direction movements obtained by two types of the nearest phosphorus atom interactions. The modification of the biaxial strain on the energy structure and optical-absorption property is more effective. The imaginary part of the total optical conductivity (Im σ ) can be negative around the threshold of the interband optical transition by modifying the chemical potential. Away from this frequency region, Im σ exhibits positive value. It can be used in the application of the surface plasmon propagations in multilayer dielectric structures.

Stress/strain changes and triggered seismicity at The Geysers, California

Science.gov (United States)

Gomberg, Joan; Davis, Scott

1996-01-01

The principal results of this study of remotely triggered seismicity in The Geysers geothermal field are the demonstration that triggering (initiation of earthquake failure) depends on a critical strain threshold and that the threshold level increases with decreasing frequency, or, equivalently, depends on strain rate. This threshold function derives from (1) analyses of dynamic strains associated with surface waves of the triggering earthquakes, (2) statistically measured aftershock zone dimensions, and (3) analytic functional representations of strains associated with power production and tides. The threshold is also consistent with triggering by static strain changes and implies that both static and dynamic strains may cause aftershocks. The observation that triggered seismicity probably occurs in addition to background activity also provides an important constraint on the triggering process. Assuming the physical processes underlying earthquake nucleation to be the same, Gomberg [this issue] discusses seismicity triggered by the MW 7.3 Landers earthquake, its constraints on the variability of triggering thresholds with site, and the implications of time delays between triggering and triggered earthquakes. Our results enable us to reject the hypothesis that dynamic strains simply nudge prestressed faults over a Coulomb failure threshold sooner than they would have otherwise. We interpret the rate-dependent triggering threshold as evidence of several competing processes with different time constants, the faster one(s) facilitating failure and the other(s) inhibiting it. Such competition is a common feature of theories of slip instability. All these results, not surprisingly, imply that to understand earthquake triggering one must consider not only simple failure criteria requiring exceedence of some constant threshold but also the requirements for generating instabilities.

Stress/strain changes and triggered seismicity at The Geysers, California

Science.gov (United States)

Gomberg, J.; Davis, S.

1996-01-01

The principal results of this study of remotely triggered seismicity in The Geysers geothermal field are the demonstration that triggering (initiation of earthquake failure) depends on a critical strain threshold and that the threshold level increases with decreasing frequency or equivalently, depends on strain rate. This threshold function derives from (1) analyses of dynamic strains associated with surface waves of the triggering earthquakes, (2) statistically measured aftershock zone dimensions, and (3) analytic functional representations of strains associated with power production and tides. The threshold is also consistent with triggering by static strain changes and implies that both static and dynamic strains may cause aftershocks. The observation that triggered seismicity probably occurs in addition to background activity also provides an important constraint on the triggering process. Assuming the physical processes underlying earthquake nucleation to be the same, Gomberg [this issue] discusses seismicity triggered by the MW 7.3 Landers earthquake, its constraints on the variability of triggering thresholds with site, and the implications of time delays between triggering and triggered earthquakes. Our results enable us to reject the hypothesis that dynamic strains simply nudge prestressed faults over a Coulomb failure threshold sooner than they would have otherwise. We interpret the rate-dependent triggering threshold as evidence of several competing processes with different time constants, the faster one(s) facilitating failure and the other(s) inhibiting it. Such competition is a common feature of theories of slip instability. All these results, not surprisingly, imply that to understand earthquake triggering one must consider not only simple failure criteria requiring exceedence of some constant threshold but also the requirements for generating instabilities.

The level of Ischemic Modified Albumin (IMA) as risk marker for ...

African Journals Online (AJOL)

Background: Recent literature reports show large interest in ischemic modified albumin (IMA) biochemical marker for detection of myocardial injury. Special attention is focused in estimation of IMA test for the diagnosis and evaluation of myocardial ischemia as well as others acute coronary syndrome in emergency patients.

Arsenic-contaminated soils. Genetically modified Pseudomonas spp. and their arsenic-phytoremediation potential

Energy Technology Data Exchange (ETDEWEB)

Sizova, O.I.; Kochetkov, V.V.; Validov, S.Z.; Boronin, A.M. [Inst. of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Moscow (Russian Federation); Kosterin, P.V.; Lyubun, Y.V. [Inst. of Biochemistry and Physiology of Plants and Microorganisms, Russian Academy of Sciences, Saratov (Russian Federation)

2002-07-01

Sorghum was inoculated with Pseudomonas bacteria, including strains harboring an As-resistance plasmid, pBS3031, to enhance As-extraction by the plants. Pseudomonas strains (P. fluorescens 38a, P. putida 53a, and P. aureofaciens BS1393) were chosen because they are antagonistic to a wide range of phytopathogenic fungi and bacteria, and they can stimulate plant growth. The resistance of natural rhizospheric pseudomonads to sodium arsenite was assessed. Genetically modified Pseudomonas strains resistant to As(III)/As(V) were obtained via conjugation or transformation. The effects of the strains on the growth of sorghum on sodium-arsenite-containing soils were assessed. The conclusions from this study are: (1) It is possible to increase the survivability of sorghum growing in sodium-arsenite-containing soil by using rhizosphere pseudomonads. (2) The presence of pBS3031 offers the strains a certain selective advantage in arsenite-contaminated soil. (3) The presence of pBS3031 impairs plant growth, due to the As-resistance mechanism determined by this plasmid: the transformation of the less toxic arsenate into the more toxic, plant-root-available arsenite by arsenate reductase and the active removal of arsenite from bacterial cells. (4) Such a mechanism makes it possible to develop a bacteria-assisted phytoremediation technology for the cleanup of As-contaminated soils and is the only possible way of removing the soil-sorbed arsenates from the environment. (orig.)

Hanford Site background: Part 1, Soil background for nonradioactive analytes

International Nuclear Information System (INIS)

1993-04-01

Volume two contains the following appendices: Description of soil sampling sites; sampling narrative; raw data soil background; background data analysis; sitewide background soil sampling plan; and use of soil background data for the detection of contamination at waste management unit on the Hanford Site

Variable characteristics of bacteriocin-producing Streptococcus salivarius strains isolated from Malaysian subjects.

Directory of Open Access Journals (Sweden)

Abdelahhad Barbour

Full Text Available BACKGROUND: Salivaricins are bacteriocins produced by Streptococcus salivarius, some strains of which can have significant probiotic effects. S. salivarius strains were isolated from Malaysian subjects showing variable antimicrobial activity, metabolic profile, antibiotic susceptibility and lantibiotic production. METHODOLOGY/PRINCIPAL FINDINGS: In this study we report new S. salivarius strains isolated from Malaysian subjects with potential as probiotics. Safety assessment of these strains included their antibiotic susceptibility and metabolic profiles. Genome sequencing using Illumina's MiSeq system was performed for both strains NU10 and YU10 and demonstrating the absence of any known streptococcal virulence determinants indicating that these strains are safe for subsequent use as probiotics. Strain NU10 was found to harbour genes encoding salivaricins A and 9 while strain YU10 was shown to harbour genes encoding salivaricins A3, G32, streptin and slnA1 lantibiotic-like protein. Strain GT2 was shown to harbour genes encoding a large non-lantibiotic bacteriocin (salivaricin-MPS. A new medium for maximum biomass production buffered with 2-(N-morpholinoethanesulfonic acid (MES was developed and showed better biomass accumulation compared with other commercial media. Furthermore, we extracted and purified salivaricin 9 (by strain NU10 and salivaricin G32 (by strain YU10 from S. salivarius cells grown aerobically in this medium. In addition to bacteriocin production, S. salivarius strains produced levan-sucrase which was detected by a specific ESI-LC-MS/MS method which indicates additional health benefits from the developed strains. CONCLUSION: The current study established the bacteriocin, levan-sucrase production and basic safety features of S. salivarius strains isolated from healthy Malaysian subjects demonstrating their potential for use as probiotics. A new bacteriocin-production medium was developed with potential scale up application for

Surface Topography and Mechanical Strain Promote Keratocyte Phenotype and Extracellular Matrix Formation in a Biomimetic 3D Corneal Model.

Science.gov (United States)

Zhang, Wei; Chen, Jialin; Backman, Ludvig J; Malm, Adam D; Danielson, Patrik

2017-03-01

The optimal functionality of the native corneal stroma is mainly dependent on the well-ordered arrangement of extracellular matrix (ECM) and the pressurized structure. In order to develop an in vitro corneal model, it is crucial to mimic the in vivo microenvironment of the cornea. In this study, the influence of surface topography and mechanical strain on keratocyte phenotype and ECM formation within a biomimetic 3D corneal model is studied. By modifying the surface topography of materials, it is found that patterned silk fibroin film with 600 grooves mm -1 optimally supports cell alignment and ECM arrangement. Furthermore, treatment with 3% dome-shaped mechanical strain, which resembles the shape and mechanics of native cornea, significantly enhances the expression of keratocyte markers as compared to flat-shaped strain. Accordingly, a biomimetic 3D corneal model, in the form of a collagen-modified, silk fibroin-patterned construct subjected to 3% dome-shaped strain, is created. Compared to traditional 2D cultures, it supports a significantly higher expression of keratocyte and ECM markers, and in conclusion better maintains keratocyte phenotype, alignment, and fusiform cell shape. Therefore, the novel biomimetic 3D corneal model developed in this study serves as a useful in vitro 3D culture model to improve current 2D cultures for corneal studies. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Modifiers of notch transcriptional activity identified by genome-wide RNAi

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Firnhaber Christopher B

2010-10-01

Full Text Available Abstract Background The Notch signaling pathway regulates a diverse array of developmental processes, and aberrant Notch signaling can lead to diseases, including cancer. To obtain a more comprehensive understanding of the genetic network that integrates into Notch signaling, we performed a genome-wide RNAi screen in Drosophila cell culture to identify genes that modify Notch-dependent transcription. Results Employing complementary data analyses, we found 399 putative modifiers: 189 promoting and 210 antagonizing Notch activated transcription. These modifiers included several known Notch interactors, validating the robustness of the assay. Many novel modifiers were also identified, covering a range of cellular localizations from the extracellular matrix to the nucleus, as well as a large number of proteins with unknown function. Chromatin-modifying proteins represent a major class of genes identified, including histone deacetylase and demethylase complex components and other chromatin modifying, remodeling and replacement factors. A protein-protein interaction map of the Notch-dependent transcription modifiers revealed that a large number of the identified proteins interact physically with these core chromatin components. Conclusions The genome-wide RNAi screen identified many genes that can modulate Notch transcriptional output. A protein interaction map of the identified genes highlighted a network of chromatin-modifying enzymes and remodelers that regulate Notch transcription. Our results open new avenues to explore the mechanisms of Notch signal regulation and the integration of this pathway into diverse cellular processes.

Strain hardening behavior and microstructural evolution during plastic deformation of dual phase, non-grain oriented electrical and AISI 304 steels

Energy Technology Data Exchange (ETDEWEB)

Soares, Guilherme Corrêa; Gonzalez, Berenice Mendonça; Arruda Santos, Leandro de, E-mail: leandro.arruda@demet.ufmg.br

2017-01-27

Strain hardening behavior and microstructural evolution of non-grain oriented electrical, dual phase, and AISI 304 steels, subjected to uniaxial tensile tests, were investigated in this study. Tensile tests were performed at room temperature and the strain hardening behavior of the steels was characterized by three different parameters: modified Crussard–Jaoul stages, strain hardening rate and instantaneous strain hardening exponent. Optical microscopic analysis, X-ray diffraction measurements, phase quantification by Rietveld refinement and hardness tests were also carried out in order to correlate the microstructural and mechanical responses to plastic deformation. Distinct strain hardening stages were observed in the steels in terms of the instantaneous strain hardening exponent and the strain hardening rate. The dual phase and non-grain oriented steels exhibited a two-stage strain hardening behavior while the AISI 304 steel displayed multiple stages, resulting in a more complex strain hardening behavior. The dual phase steels showed a high work hardening capacity in stage 1, which was gradually reduced in stage 2. On the other hand, the AISI 304 steel showed high strain hardening capacity, which continued to increase up to the tensile strength. This is a consequence of its additional strain hardening mechanism, based on a strain-induced martensitic transformation, as shown by the X-ray diffraction and optical microscopic analyses.

Trunk position modulates anterior cruciate ligament forces and strains during a single-leg squat

NARCIS (Netherlands)

Kulas, Anthony S.; Hortobagyi, Tibor; DeVita, Paul

Background: Although the squat exercise and its variations are commonly prescribed for anterior cruciate ligament rehabilitation, whether trunk position affects these ligament forces and strains during the squat is unclear. Our purpose was to evaluate the effects of trunk position on anterior

Heat treatment effect on the strain dependence of the critical current for an internal-tin processed Nb3Sn strand

International Nuclear Information System (INIS)

Oh, Sangjun; Park, Soo-Hyeon; Lee, Chulhee; Choi, Heekyung; Kim, Keeman

2010-01-01

A comparative study on the effects of heat treatment, especially, the duration of the A15 reaction temperature plateau on the strain dependence of the critical current for an internal-tin processed Nb 3 Sn strand has been carried out. The strain dependence of the critical current is measured by a variable temperature Walter spiral probe that we have developed. It was shown that prolonged heat treatment can be a very effective way to improve the strain dependency. For a quantitative analysis, the measured data were analyzed with various proposed scaling laws: the scaling law based on strong-coupling theory, the modified deviatoric strain scaling law, and the interpolative scaling law. We found that there is a slight increase in the critical temperature and a substantial improvement in the maximum pinning force. The origin of improved strain dependency is further discussed.

Authentic display of a cholera toxin epitope by chimeric type 1 fimbriae: effects of insert position and host background

DEFF Research Database (Denmark)

Stentebjerg-Olesen, B; Pallesen, L; Jensen, LB

1997-01-01

. Several of the chosen positions seemed amenable even for large foreign inserts; the chimeric proteins were exposed on the bacterial surface and the cholera toxin epitope was authentically displayed, i.e. it was recognized on bacteria by specific antiserum. Display of chimeric fimbriae was tested...... with respect to host background in three different Escherichia coli strains, i.e. an isogenic set of K-12 strains, differing in the presence of an indigenous fim gene cluster, as well as a wild-type isolate. Immunization of rabbits with purified chimeric fimbriae resulted in serum which specifically recognized...

An exponential strain dependent Rusinek–Klepaczko model for flow stress prediction in austenitic stainless steel 304 at elevated temperatures

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Amit Kumar Gupta

2014-10-01

Full Text Available In this paper, to predict flow stress of Austenitic Stainless Steel (ASS 304 at elevated temperatures the extended Rusinek–Klepaczko (RK model has been modified using an exponential strain dependent term for dynamic strain aging (DSA region. Isothermal tensile tests are conducted on ASS 304 for a temperature range of 323–923 K with an interval of 50 K and at strain rates of 0.0001 s−1, 0.001 s−1, 0.01 s−1 and 0.1 s−1. DSA phenomenon is observed from 623 to 923 K at 0.0001 s−1, 0.001 s−1 and 0.01 s−1. Material constants are calculated using data obtained from these tensile tests for non-DSA and DSA region separately. The predicted results from the RK model are compared with the experimental data to check the accuracy of the constitutive relation. It is observed that to find out the constants of this model, some initial assumptions are required, and these initial values affect the predicted values. Hence, Genetic Algorithm (GA is used to optimize the constants for RK model. Statistical measures such as the correlation coefficient, the average absolute error and standard deviation are used to measure the accuracy of the model. The resulting values of the correlation coefficient for ASS 304 for non-DSA and DSA region using modified extended RK model are 0.9828 and 0.9701. This modified, extended RK model is compared with Johnson–Cook (JC, Zerilli–Armstrong (ZA and Arrhenius models and it is observed that specifically in DSA region, the modified extended RK model gives highly accurate predictions.

A statistical background noise correction sensitive to the steadiness of background noise.

Science.gov (United States)

Oppenheimer, Charles H

2016-10-01

A statistical background noise correction is developed for removing background noise contributions from measured source levels, producing a background noise-corrected source level. Like the standard background noise corrections of ISO 3741, ISO 3744, ISO 3745, and ISO 11201, the statistical background correction increases as the background level approaches the measured source level, decreasing the background noise-corrected source level. Unlike the standard corrections, the statistical background correction increases with steadiness of the background and is excluded from use when background fluctuation could be responsible for measured differences between the source and background noise levels. The statistical background noise correction has several advantages over the standard correction: (1) enveloping the true source with known confidence, (2) assuring physical source descriptions when measuring sources in fluctuating backgrounds, (3) reducing background corrected source descriptions by 1 to 8 dB for sources in steady backgrounds, and (4) providing a means to replace standardized background correction caps that incentivize against high precision grade methods.

Strain tuneable whispering gallery mode resonators in the estimation of the elasto-optic parameters of soft materials

Science.gov (United States)

Pissadakis, Stavros; Milenko, Karolina; Aluculesei, Alina; Fytas, George

2016-04-01

In this manuscript we present the fabrication and characterization of a novel, polymer whispering gallery modes (WGMs) spherical micro-resonator, formed around the waist of an optical fiber taper. Fiber taper with well attached spheroid works as a cord, fixed on two ends enabling strain application to the resonator body. Controllable elastic elongation of the encapsulated fiber taper causes a change in the shape of the spheroid, which modifies the diameter and directional refractive index of the cavity. These changes influence the wavelength position of the WGMs resonances with a linear blue shift up to 0.6 nm, with corresponding strains up to 700Μɛ. The strain induced WGMs shift with respect to resonator diameter and annealing process is presented and analyzed.

Detection and characterization of multidrug-resistant enterobacteria bearing aminoglycoside-modifying gene in a university hospital at Rio de Janeiro, Brazil, along three decades.

Science.gov (United States)

Dias-Gonçalves, Verônica; Bohrer-Lengruber, Françoise; Oliveira-Fonseca, Bianca; Santos-Pereira, Renata Meirelles; Barbosa de Melo, Luis Dione; Gazos-Lopes, Ulisses; Ribeiro-Bello, Alexandre; Adler-Pereira, José Augusto

2015-01-01

Multidrug-resistant Enterobacteriaceae, particularly those resistant to gentamicin, have become one of the most important causes of nosocomial infections. We sought to investigate the presence of genes conferring resistance to aminoglycosides, specially to gentamicin, in Klebsiella pneumoniae and Escherichia coli multidrug-resistant strains isolated from different clinical materials among patients hospitalized in a university hospital in Rio de Janeiro, Brazil. Ten colonization strains and 20 infection strains were evaluated during three decades (1980 to 2010) using selective media containing 8 µg/ml of gentamicin. Thirty strains were tested for antimicrobial susceptibility. Twenty two strains were subjected to plasmid DNA extraction and 12 to hybridization assays using as probe a 1.9 kb plasmid DNA fragment from one of the K. pneumoniae strains isolated from faecal samples. This fragment was sequenced and assigned to the GQ422439 GenBank record. PCR was also performed using oligonucleotides designed for aminoglycoside-modifying enzymes. An accC2 acetylase, besides transposons and insertion sequences, were evidenced. Twenty-four (80%) of the isolates were positive for the aacC2 gene in agreement with antibiotic susceptibility testing profiles, indicating the persistent presence of this gene throughout the three decades. We detected high molecular weight plasmids in 54,5% of the strains. Of the tested strains, 91% showed positive signal in the hybridization assays. A gene codifying for one specific aminoglycoside-modifying enzyme was detected all throughout the three decades. Our data back the adoption of preventive measures, such as a more conscious use of antimicrobial agents in hospital environments, which can contribute to control the dissemination of microorganisms harboring resistance gene plasmids.

Rapid focused sequencing: a multiplexed assay for simultaneous detection and strain typing of Bacillus anthracis, Francisella tularensis, and Yersinia pestis.

Directory of Open Access Journals (Sweden)

Rosemary S Turingan

Full Text Available BACKGROUND: The intentional release of Bacillus anthracis in the United States in 2001 has heightened concern about the use of pathogenic microorganisms in bioterrorism attacks. Many of the deadliest bacteria, including the Class A Select Agents Bacillus anthracis, Francisella tularensis, and Yersinia pestis, are highly infectious via the pulmonary route when released in aerosolized form. Hence, rapid, sensitive, and reliable methods for detection of these biothreats and characterization of their potential impact on the exposed population are of critical importance to initiate and support rapid military, public health, and clinical responses. METHODOLOGY/PRINCIPAL FINDINGS: We have developed microfluidic multiplexed PCR and sequencing assays based on the simultaneous interrogation of three pathogens per assay and ten loci per pathogen. Microfluidic separation of amplified fluorescently labeled fragments generated characteristic electrophoretic signatures for identification of each agent. The three sets of primers allowed significant strain typing and discrimination from non-pathogenic closely-related species and environmental background strains based on amplicon sizes alone. Furthermore, sequencing of the 10 amplicons per pathogen, termed "Rapid Focused Sequencing," allowed an even greater degree of strain discrimination and, in some cases, can be used to determine virulence. Both amplification and sequencing assays were performed in microfluidic biochips developed for fast thermal cycling and requiring 7 µL per reaction. The 30-plex sequencing assay resulted in genotypic resolution of 84 representative strains belonging to each of the three biothreat species. CONCLUSIONS/SIGNIFICANCE: The microfluidic multiplexed assays allowed identification and strain differentiation of the biothreat agents Bacillus anthracis, Francisella tularensis, and Yersinia pestis and clear discrimination from closely-related species and several environmental

The use of flagella and motility for plant colonization and fitness by different strains of the foodborne pathogen Listeria monocytogenes.

Directory of Open Access Journals (Sweden)

Lisa Gorski

Full Text Available The role of flagella and motility in the attachment of the foodborne pathogen Listeria monocytogenes to various surfaces is mixed with some systems requiring flagella for an interaction and others needing only motility for cells to get to the surface. In nature this bacterium is a saprophyte and contaminated produce is an avenue for infection. Previous studies have documented the ability of this organism to attach to and colonize plant tissue. Motility mutants were generated in three wild type strains of L. monocytogenes by deleting either flaA, the gene encoding flagellin, or motAB, genes encoding part of the flagellar motor, and tested for both the ability to colonize sprouts and for the fitness of that colonization. The motAB mutants were not affected in the colonization of alfalfa, radish, and broccoli sprouts; however, some of the flaA mutants showed reduced colonization ability. The best colonizing wild type strain was reduced in colonization on all three sprout types as a result of a flaA deletion. A mutant in another background was only affected on alfalfa. The third, a poor alfalfa colonizer was not affected in colonization ability by any of the deletions. Fitness of colonization was measured in experiments of competition between mixtures of mutant and parent strains on sprouts. Here the flaA and motAB mutants of the three strain backgrounds were impaired in fitness of colonization of alfalfa and radish sprouts, and one strain background showed reduced fitness of both mutant types on broccoli sprouts. Together these data indicate a role for flagella for some strains to physically colonize some plants, while the fitness of that colonization is positively affected by motility in almost all cases.

Structural characterization of bioengineered α-D-glucans produced by mutant glucansucrase GTF180 enzymes of lactobacillus reuteri strain 180

NARCIS (Netherlands)

Leeuwen, S.S. van; Kralj, S.; Eeuwema, W.; Gerwig, G.J.; Dijkhuizen, L.; Kamerling, J.P.

2009-01-01

Mutagenesis of specific amino acid residues of the glucansucrase (GTF180) enzyme from Lactobacillus reuteri strain 180 yielded 12 mutant enzymes that produced modified exopolysaccharides (mEPSs) from sucrose. Ethanol-precipitated and purified mEPSs were subjected to linkage analysis, Smith

Structural Characterization of Bioengineered alpha-D-Glucans Produced by Mutant Glucansucrase GTF180 Enzymes of Lactobacillus reuteri Strain 180

NARCIS (Netherlands)

van Leeuwen, Sander S.; Kralj, Slavko; Eeuwema, Wieger; Gerwig, Gerrit J.; Dijkhuizen, Lubbert; Kamerling, Johannis P.

Mutagenesis of specific amino acid residues of the glucansucrase (GTF180) enzyme from Lactobacillus reuteri strain 180 yielded 12 mutant enzymes that produced modified exopolysaccharides (mEPSs) from sucrose. Ethanol-precipitated and purified mEPSs were subjected to linkage analysis, Smith

Thermal-work strain in law enforcement personnel during chemical, biological, radiological, and nuclear (CBRN) training

Science.gov (United States)

Yokota, M; Karis, A J; Tharion, W J

2014-01-01

Background: Thermal safety standards for the use of chemical, biological, radiological, and nuclear (CBRN) ensembles have been established for various US occupations, but not for law enforcement personnel. Objectives: We examined thermal strain levels of 30 male US law enforcement personnel who participated in CBRN field training in Arizona, Florida, and Massachusetts. Methods: Physiological responses were examined using unobtrusive heart rate (HR) monitors and a simple thermoregulatory model to predict core temperature (Tc) using HR and environment. Results: Thermal strain levels varied by environments, activity levels, and type of CBRN ensemble. Arizona and Florida volunteers working in hot-dry and hot-humid environment indicated high heat strain (predicted max Tc>38.5°C). The cool environment of Massachusetts reduced thermal strain although thermal strains were occasionally moderate. Conclusions: The non-invasive method of using physiological monitoring and thermoregulatory modeling could improve law enforcement mission to reduce the risk of heat illness or injury. PMID:24999847

Modelling and simulation of dynamic recrystallization (DRX) in OFHC copper at very high strain rates

Science.gov (United States)

Testa, G.; Bonora, N.; Ruggiero, A.; Iannitti, G.; Persechino, I.; Hörnqvist, M.; Mortazavi, N.

2017-01-01

At high strain rates, deformation processes are essentially adiabatic and if the plastic work is large enough dynamic recrystallization can occur. In this work, an examination on microstructure evolution of OFHC copper in Dynamic Tensile Extrusion (DTE) test, performed at 400 m/s, was carried out. EBSD investigations, along the center line of the fragment remaining in the extrusion die, showed a progressive elongation of the grains, and an accompanying development of a strong + dual fiber texture. Discontinuous dynamic recrystallization (DRX) occurred at larger strains, and it was showed that nucleation occurred during straining. A criterion for DRX to occur, based on the evolution of Zener-Hollomon parameter during the dynamic deformation process, is proposed. Finally, DTE test was simulated using the modified Rusinek-Klepaczko constitutive model incorporating a model for the prediction of DRX initiation.

Incorporating comparative genomics into the design-test-learn cycle of microbial strain engineering.

Science.gov (United States)

Sardi, Maria; Gasch, Audrey P

2017-08-01

Engineering microbes with new properties is an important goal in industrial engineering, to establish biological factories for production of biofuels, commodity chemicals and pharmaceutics. But engineering microbes to produce new compounds with high yield remains a major challenge toward economically viable production. Incorporating several modern approaches, including synthetic and systems biology, metabolic modeling and regulatory rewiring, has proven to significantly advance industrial strain engineering. This review highlights how comparative genomics can also facilitate strain engineering, by identifying novel genes and pathways, regulatory mechanisms and genetic background effects for engineering. We discuss how incorporating comparative genomics into the design-test-learn cycle of strain engineering can provide novel information that complements other engineering strategies. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Chemically modified tetracyclines stimulate matrix metalloproteinase-s production by periodontal ligament cells

NARCIS (Netherlands)

Bildt, M.M.; Snoek-van Beurden, A.M.P.; Groot, J. de; El, B. van; Kuijpers-Jagtman, A.M.; Hoff, J.W. van den

2006-01-01

Background and Objective: The purpose of this study was to investigate the effects of chemically modified tetracyclines (CMTs) on the production of gelatinases [matrix metalloproteinase (MMP)-2 and -9] by human periodontal ligament (PDL) cells, and on the activity of recombinant gelatinases.

Static strain aging of Zircaloy-2: the effect of dislocation dynamics on yielding behaviour

International Nuclear Information System (INIS)

Thorpe, W.R.; Smith, I.O.

1981-01-01

The static strain-aging response of Zircaloy-2 was determined in the temperature range 293-723 K. A modified Hahn yielding model was found to provide a satisfactory description of the magnitude and shape of the yield points after aging, thereby providing information about the mobile dislocation density and the dislocation generation rate. For example, the characteristic double peak in the temperature dependence of strain aging was simplified to a single broad minimum in the mobile dislocation density over the temperature interval 500-700 K. The shape of the yield point was also found to be temperature dependent; the yield drop became less sharp at test temperatures above 648 K. This was ascribed to the inhibition of dislocation multiplication by dynamic strain aging. A kinetic law was developed by applying Snoek ordering kinetics to the process of dislocation locking and the resultant change in mobile dislocation density was then used to predict the strain-aging response as a function of aging time. The stress dependence of strain aging at 573 K was investigated at aging stresses of between 0.07 and 0.975 of the flow stress sigmasub(f). The strain-aging response increased for aging at stresses between 0.07sigmassub(f) and 0.8sigmasub(f), whereafter it declined steeply to the limit of zero at the flow stress. (Auth.)

The routine use of modified Borelli's lactritmel agar (MBLA).

Science.gov (United States)

Kaminski, G W

1985-07-01

The original formula of Borelli's lactritmel agar (BLA)(3) which contains wheat flour, milk and honey, has been modified by replacing the wheat flour with dehydrated Bacto Corn Meal Agar (Difco) and by slightly altering the concentrations of the milk and honey. The modified medium (MBLA) is less turbid, less particulate, and easier to prepare than BLA. Although Trichophyton rubrum usually produces a wine-red pigment with BLA, most strains initially produce a yellow pigment, with the red pigment developing later. The corn meal in MBLA reduces this tendency and stimulates the early formation of deep wine red pigment, MBLA enhances sporulation of dermatophytes and various fungi which fail to sporulate on other media, and maintains characteristic growth without developing pleomorphic degeneration. It has been used routinely since 1972 as a reliable aid to the differentiation of T. rubrum and T. mentagrophytes. Since 1975 selective MBLA has been used as a routine primary isolation medium for dermatophytes, and has proved to be most useful.

Targeted changes of the cell wall proteome influence Candida albicans ability to form single- and multi-strain biofilms.

Directory of Open Access Journals (Sweden)

Vitor Cabral

2014-12-01

Full Text Available Biofilm formation is an important virulence trait of the pathogenic yeast Candida albicans. We have combined gene overexpression, strain barcoding and microarray profiling to screen a library of 531 C. albicans conditional overexpression strains (∼10% of the genome for genes affecting biofilm development in mixed-population experiments. The overexpression of 16 genes increased strain occupancy within a multi-strain biofilm, whereas overexpression of 4 genes decreased it. The set of 16 genes was significantly enriched for those encoding predicted glycosylphosphatidylinositol (GPI-modified proteins, namely Ihd1/Pga36, Phr2, Pga15, Pga19, Pga22, Pga32, Pga37, Pga42 and Pga59; eight of which have been classified as pathogen-specific. Validation experiments using either individually- or competitively-grown overexpression strains revealed that the contribution of these genes to biofilm formation was variable and stage-specific. Deeper functional analysis of PGA59 and PGA22 at a single-cell resolution using atomic force microscopy showed that overexpression of either gene increased C. albicans ability to adhere to an abiotic substrate. However, unlike PGA59, PGA22 overexpression led to cell cluster formation that resulted in increased sensitivity to shear forces and decreased ability to form a single-strain biofilm. Within the multi-strain environment provided by the PGA22-non overexpressing cells, PGA22-overexpressing cells were protected from shear forces and fitter for biofilm development. Ultrastructural analysis, genome-wide transcript profiling and phenotypic analyses in a heterologous context suggested that PGA22 affects cell adherence through alteration of cell wall structure and/or function. Taken together, our findings reveal that several novel predicted GPI-modified proteins contribute to the cooperative behaviour between biofilm cells and are important participants during C. albicans biofilm formation. Moreover, they illustrate the power

Microarray BASICA: Background Adjustment, Segmentation, Image Compression and Analysis of Microarray Images

Directory of Open Access Journals (Sweden)

Jianping Hua

2004-01-01

Full Text Available This paper presents microarray BASICA: an integrated image processing tool for background adjustment, segmentation, image compression, and analysis of cDNA microarray images. BASICA uses a fast Mann-Whitney test-based algorithm to segment cDNA microarray images, and performs postprocessing to eliminate the segmentation irregularities. The segmentation results, along with the foreground and background intensities obtained with the background adjustment, are then used for independent compression of the foreground and background. We introduce a new distortion measurement for cDNA microarray image compression and devise a coding scheme by modifying the embedded block coding with optimized truncation (EBCOT algorithm (Taubman, 2000 to achieve optimal rate-distortion performance in lossy coding while still maintaining outstanding lossless compression performance. Experimental results show that the bit rate required to ensure sufficiently accurate gene expression measurement varies and depends on the quality of cDNA microarray images. For homogeneously hybridized cDNA microarray images, BASICA is able to provide from a bit rate as low as 5 bpp the gene expression data that are 99% in agreement with those of the original 32 bpp images.

From local strains to specific starters: the process structuring a research program on the activation and management of a biotechnological resource

OpenAIRE

Casalta, Erick; Bona, Pascale

2009-01-01

This study presents a research-action program carried out in Corsica with a group of cheese makers to develop specific starters. Based on the direct participation of the cheese makers, this study consisted in designing starters with lactic acid bacterial strains isolated from milks and cheeses of this group of cheese makers. This process modified an individually and empirically used resource, local strains, into a shared and collectively managed resource, specific starters. Patrimonial featur...

Strain sonoelastographic evaluation of biceps muscle intrinsic stiffness after botulinum toxin-A injection.

Science.gov (United States)

Aşkın, Ayhan; Kalaycı, Özlem Tuğçe; Bayram, Korhan Barış; Tosun, Aliye; Demirdal, Ümit Seçil; Atar, Emel; İnci, Mehmet Fatih

2017-01-01

The most commonly used clinical tools for measuring spasticity are modified Ashworth scale (MAS) and Tardieu scale but both yield subjective rather than objective results. Ultrasound elastography (EUS) provides information on tissue stiffness and allows the qualitative or quantitative measurements of the mechanical properties of tissues. To assess the stiffness of biceps brachialis muscles in stroke patients by strain EUS and to investigate the sonoelastographic changes and its correlations with clinical evaluation parameters after botulinum toxin-A (BTA) injections. This is a prospective study. A total of 48 chronic stroke patients requiring BTA injections to biceps brachialis muscles were included in the study. All patients received injections with BTA to biceps brachialis muscles under ultrasound guidance. MAS, goniometric measurements, and strain EUS assessments were performed at preintervention and at 4-week postintervention. Strain index values of biceps muscle on the affected side were significantly increased compared with those on the unaffected side (p < 0.01). At 4 weeks after BTA injection, significant improvements were observed in MAS grades and goniometric measurements (p < 0.05). Statistically significant differences were also found between the MAS grades and strain index values in both pre-/postintervention period (p < 0.01). No significant correlations were observed between clinical parameters and strain EUS findings. Strain EUS is a promising diagnostic tool for assessing stiffness in spastic muscles, in establishing the treatment plan and monitoring the effectiveness of the therapeutic modality.

Identification of novel conserved functional motifs across most Influenza A viral strains

Directory of Open Access Journals (Sweden)

El-Azab Iman

2011-01-01

Full Text Available Abstract Background Influenza A virus poses a continuous threat to global public health. Design of novel universal drugs and vaccine requires a careful analysis of different strains of Influenza A viral genome from diverse hosts and subtypes. We performed a systematic in silico analysis of Influenza A viral segments of all available Influenza A viral strains and subtypes and grouped them based on host, subtype, and years isolated, and through multiple sequence alignments we extrapolated conserved regions, motifs, and accessible regions for functional mapping and annotation. Results Across all species and strains 87 highly conserved regions (conservation percentage > = 90% and 19 functional motifs (conservation percentage = 100% were found in PB2, PB1, PA, NP, M, and NS segments. The conservation percentage of these segments ranged between 94 - 98% in human strains (the most conserved, 85 - 93% in swine strains (the most variable, and 91 - 94% in avian strains. The most conserved segment was different in each host (PB1 for human strains, NS for avian strains, and M for swine strains. Target accessibility prediction yielded 324 accessible regions, with a single stranded probability > 0.5, of which 78 coincided with conserved regions. Some of the interesting annotations in these regions included sites for protein-protein interactions, the RNA binding groove, and the proton ion channel. Conclusions The influenza virus has evolved to adapt to its host through variations in the GC content and conservation percentage of the conserved regions. Nineteen universal conserved functional motifs were discovered, of which some were accessible regions with interesting biological functions. These regions will serve as a foundation for universal drug targets as well as universal vaccine design.

Emergence of canine distemper virus strains with modified molecular signature and enhanced neuronal tropism leading to high mortality in wild carnivores.

Science.gov (United States)

Origgi, F C; Plattet, P; Sattler, U; Robert, N; Casaubon, J; Mavrot, F; Pewsner, M; Wu, N; Giovannini, S; Oevermann, A; Stoffel, M H; Gaschen, V; Segner, H; Ryser-Degiorgis, M-P

2012-11-01

An ongoing canine distemper epidemic was first detected in Switzerland in the spring of 2009. Compared to previous local canine distemper outbreaks, it was characterized by unusually high morbidity and mortality, rapid spread over the country, and susceptibility of several wild carnivore species. Here, the authors describe the associated pathologic changes and phylogenetic and biological features of a multiple highly virulent canine distemper virus (CDV) strain detected in and/or isolated from red foxes (Vulpes vulpes), Eurasian badgers (Meles meles), stone (Martes foina) and pine (Martes martes) martens, from a Eurasian lynx (Lynx lynx), and a domestic dog. The main lesions included interstitial to bronchointerstitial pneumonia and meningopolioencephalitis, whereas demyelination--the classic presentation of CDV infection--was observed in few cases only. In the brain lesions, viral inclusions were mainly in the nuclei of the neurons. Some significant differences in brain and lung lesions were observed between foxes and mustelids. Swiss CDV isolates shared together with a Hungarian CDV strain detected in 2004. In vitro analysis of the hemagglutinin protein from one of the Swiss CDV strains revealed functional and structural differences from that of the reference strain A75/17, with the Swiss strain showing increased surface expression and binding efficiency to the signaling lymphocyte activation molecule (SLAM). These features might be part of a novel molecular signature, which might have contributed to an increase in virus pathogenicity, partially explaining the high morbidity and mortality, the rapid spread, and the large host spectrum observed in this outbreak.

RESEARCH IN SENSITIVITY TO ANTIBIOTICS, ANTISEPTICS IN PSEUDOMONAS AERUGINOSA STRAINS ISOLATED FROM PATIENTS WITH INFECTIOUS COMPLICATIONS

OpenAIRE

O. A. Nazarchuk; D. V. Paliy; N. I. Osadchuk

2017-01-01

Background. Infections caused by Pseudomonas are one of the topical issues of medicine. Objective. The aim of the research was to study sensityvity to antibiotics, antiseptics of P. aeruginosa clinical strains that cause infectious complications in patients with burns. Methods. Microbiological study of biological material, received from 435 patients with burns of the 3rd-4th stages (2011-2015 years). In early terms of burn disease 127 clinical strains of P. aeruginosa were isolated fr...

Low cycle fatigue strength of austenitic stainless steel under large strain regime

International Nuclear Information System (INIS)

Sakai, Michiya; Saito, Kiyoshi; Matsuura, Shinichi

1998-01-01

In order to establish realistic seismic safety of nuclear power plants, it is necessary to clarify the failure mode of each components and prepare a damage evaluation method. The authors have proposed the damage evaluation method based on the fully numerical approach to evaluate the low cycle fatigue (LCF) failure under seismic loadings. This method has been validated by comparison with the dynamic failure tests of thin elbows which should be the one of the important components of the FBR primary piping system. However, since there exists limited LCF data, fatigue lives under large strain regime have been extrapolated by available fatigue data. In this study, LCF tests have been conducted over a large strain range from 2% to 10% on austenitic stainless steel SUS304. From the results, the regressive LCF curve has been proposed to modify the Wada's best-fit LCF curve under large strain regime. The usage factors calculated by author's numerical approach using proposed LCF curve have been improved to correct the underestimation of the fatigue damage. (author)

Genome Sequence of Saccharomyces cerevisiae Strain Kagoshima No. 2, Used for Brewing the Japanese Distilled Spirit Shōchū.

Science.gov (United States)

Mori, Kazuki; Kadooka, Chihiro; Masuda, Chika; Muto, Ai; Okutsu, Kayu; Yoshizaki, Yumiko; Takamine, Kazunori; Futagami, Taiki; Tamaki, Hisanori

2017-10-12

Here, we report a draft genome sequence of Saccharomyces cerevisiae strain Kagoshima no. 2, which is used for brewing shōchū, a traditional distilled spirit in Japan. The genome data will facilitate an understanding of the evolutional traits and genetic background related to the characteristic features of strain Kagoshima no. 2. Copyright © 2017 Mori et al.

Molecular characterization of Mycobacterium bovis strains isolated from cattle slaughtered at two abattoirs in Algeria

Directory of Open Access Journals (Sweden)

Ouzrout Rachid

2009-01-01

Full Text Available Abstract Background Bovine Tuberculosis is prevalent in Algeria despite governmental attempts to control the disease. The objective of this study was to conduct, for the first time, molecular characterization of a population sample of Mycobacterium bovis strains isolated from slaughter cattle in Algeria. Between August and November 2007, 7250 animals were consecutively screened at the abattoirs of Algiers and Blida. In 260 animals, gross visible granulomatous lesions were detected and put into culture. Bacterial isolates were subsequently analysed by molecular methods. Results Altogether, 101 bacterial strains from 100 animals were subjected to molecular characterization. M. bovis was isolated from 88 animals. Other bacteria isolated included one strain of M. caprae, four Rhodococcus equi strains, three Non-tuberculous Mycobacteria (NTM and five strains of other bacterial species. The M. bovis strains isolated showed 22 different spoligotype patterns; four of them had not been previously reported. The majority of M. bovis strains (89% showed spoligotype patterns that were previously observed in strains from European cattle. Variable Number of Tandem Repeat (VNTR typing supported a link between M. bovis strains from Algeria and France. One spoligotype pattern has also been shown to be frequent in M. bovis strains from Mali although the VNTR pattern of the Algerian strains differed from the Malian strains. Conclusion M. bovis infections account for a high amount of granulomatous lesions detected in Algerian slaughter cattle during standard meat inspection at Algiers and Blida abattoir. Molecular typing results suggested a link between Algerian and European strains of M. bovis.

Antimicrobial properties of lactic acid bacteria isolated from traditional yogurt and milk against Shigella strains.

Science.gov (United States)

Zare Mirzaei, Elnaze; Lashani, Elahe; Davoodabadi, Abolfazl

2018-01-01

Background: Lactic acid bacteria (LAB) are normal flora of the mouth, intestines and the female genital tract. They are also frequently found in meat, vegetables, and dairy products. Most of probiotic bacteria belong to the LAB group. Some probiotic LAB are useful in prevention and treatment of diarrheal diseases. The aim of this study was to investigate the antimicrobial properties of LAB isolated from traditional yogurt and milk against Shigella strains. Materials and methods: Forty LAB strains were isolated from traditional yogurt and milk. The antimicrobial activity of LAB against Shigella strains (eight S. flexneri , four S. sonnei ) was examined using the agar-well diffusion assay. LAB strains with antimicrobial effect against all Shigella strains were identified by 16S rRNA gene sequencing. Results: Six LAB strains inhibited the growth of all 12 Shigella strains. Lb. paracasei Y1-3, Lb. paracasei Y8-1 and Lb. fermentum Y2-2 were isolated from yogurt. Lb. paracasei M18-1, Lb. parelimentarius M4-3 and Lb. plantarum M19-1 were isolated from milk. Conclusion: This study showed that Lactobacillus strains with good inhibitory activity against S. flexneri and S. sonnei could be isolated from traditional yogurt and milk.

The efficiency of Arabidopsis thaliana floral dip transformation is determined not only by the Agrobacterium strain used but also by the physiology and the ecotype of the dipped plant.

Science.gov (United States)

Ghedira, Rim; De Buck, Sylvie; Nolf, Jonah; Depicker, Ann

2013-07-01

To evaluate the chromosomal background of different Agrobacterium strains on floral dip transformation frequency, eight wild-type Agrobacterium strains, provided by Laboratorium voor Microbiologie Gent (LMG) and classified in different genomic groups, were compared with the commonly used Agrobacterium strains C58C1 Rif(r) (pMP90) and LBA4404 in Arabidopsis thaliana Columbia (Col-0) and C24 ecotypes. The C58C1 Rif(r) chromosomal background in combination with the pMP90 virulence plasmid showed high Col-0 floral dip transformation frequencies (0.76 to 1.57%). LMG201, which is genetically close to the Agrobacterium C58 strain, with the same virulence plasmid showed comparable or even higher transformation frequencies (1.22 to 2.28%), whereas the LBA4404 strain displayed reproducibly lower transformation frequencies (Agrobacterium chromosomal backgrounds had transformation frequencies between those of the C58C1 Rif(r) (pMP90) and LBA4404 reference strains. None of the strains could transform the C24 ecotype with a frequency higher than 0.1%. Strikingly, all Arabidopsis Col-0 floral dip transformation experiments showed a high transformation variability from plant to plant (even more than 50-fold) within and across the performed biological repeats for all analyzed Agrobacterium strains. Therefore, the physiology of the plant and, probably, the availability of competent flowers to be transformed determine, to a large extent, floral dip transformation frequencies.

Strain-Specificity and Disease-Specificity of Probiotic Efficacy: A Systematic Review and Meta-Analysis

Directory of Open Access Journals (Sweden)

Lynne V. McFarland

2018-05-01

Full Text Available BackgroundAs the use and diversity of probiotic products expands, the choice of an appropriate type of probiotic is challenging for both medical care professionals and the public alike. Two vital factors in choosing the appropriate probiotic are often ignored, namely, the probiotic strain-specificity and disease-specificity for efficacy. Reviews and meta-analyses often pool together different types of probiotics, resulting in misleading conclusions of efficacy.MethodsA systematic review of the literature (1970–2017 assessing strain-specific and disease-specific probiotic efficacy was conducted. Trials were included for probiotics with an identifiable strain (either single strain or mixtures of strains that had at least two randomized, controlled trials for each type of disease indication. The goal was to determine if probiotic strains have strain and/or disease-specific efficacy.ResultsWe included 228 trials and found evidence for both strain specificity and disease specificity for the efficacy of specific probiotic strains. Significant efficacy evidence was found for 7 (70% of probiotic strain(s among four preventive indications and 11 (65% probiotic strain(s among five treatment indications. Strain-specific efficacy for preventing adult antibiotic-associated diarrhea was clearly demonstrated within the Lactobacillus species [e.g., by the mixture of Lactobacillus acidophilus CL1285, Lactobacillus casei LBC80R, and Lactobacillus rhamnosus CLR2 (Bio-K+®, by L. casei DN114001 (Actimel® and by Lactobacillus reuteri 55730], while other Lactobacillus strains did not show efficacy. Significant disease-specific variations in efficacy was demonstrated by L. rhamnosus GG and Saccharomyces boulardii CNCM I-745, as well as other probiotic strains.ConclusionStrong evidence was found supporting the hypothesis that the efficacy of probiotics is both strain-specific and disease-specific. Clinical guidelines and meta-analyses need to recognize the

Modified clay minerals efficiency against chemical and biological warfare agents for civil human protection.

Science.gov (United States)

Plachá, Daniela; Rosenbergová, Kateřina; Slabotínský, Jiří; Kutláková, Kateřina Mamulová; Studentová, Soňa; Martynková, Gražyna Simha

2014-04-30

Sorption efficiencies of modified montmorillonite and vermiculite of their mono ionic Na and organic HDTMA and HDP forms were studied against chemical and biological warfare agents such as yperite and selected bacterial strains. Yperite interactions with modified clay minerals were observed through its capture in low-density polyethylene foil-modified clay composites by measuring yperite gas permeation with using chemical indication and gas chromatography methods. The antibacterial activities of synthetized organoclays were tested against selected Gram-positive and Gram-negative bacterial species in minimum inhibitory concentration tests. The obtained results showed a positive influence of modified clay minerals on the significant yperite breakthrough-time increase. The most effective material was the polyethylene-Na form montmorillonite, while the polyethylene-Na form vermiculite showed the lowest efficiency. With increasing organic cations loading in the interlayer space the montmorillonite efficiency decreased, and in the case of vermiculite an opposite effect was observed. Generally the modified montmorillonites were more effective than modified vermiculites. The HDP cations seem to be more effective compare to the HDTMA. The antibacterial activity tests confirmed efficiency of all organically modified clay minerals against Gram-positive bacteria. The confirmation of antibacterial activity against Y. pestis, plague bacteria, is the most interesting result of this part of the study. Copyright © 2014 Elsevier B.V. All rights reserved.

A strain gauge

DEFF Research Database (Denmark)

2016-01-01

The invention relates to a strain gauge of a carrier layer and a meandering measurement grid positioned on the carrier layer, wherein the strain gauge comprises two reinforcement members positioned on the carrier layer at opposite ends of the measurement grid in the axial direction....... The reinforcement members are each placed within a certain axial distance to the measurement grid with the axial distance being equal to or smaller than a factor times the grid spacing. The invention further relates to a multi-axial strain gauge such as a bi-axial strain gauge or a strain gauge rosette where each...... of the strain gauges comprises reinforcement members. The invention further relates to a method for manufacturing a strain gauge as mentioned above....

Reduction factors for creep strength and fatigue life of modified 9 Cr-1 Mo steel weldments

International Nuclear Information System (INIS)

Blass, J.J.; Battiste, R.L.; O'Connor, D.G.

1991-01-01

The provisions of ASME B ampersand PV Code Case N-47 currently include reduction factors for creep strength and fatigue life of weldments. To provide experimental confirmation of such factors for modified 9 Cr-1 Mo steel, tests of tubular specimens were conducted at 538 degree C (1000 degree F). Three creep-rupture specimens with longitudinal welds were tested in tension; and, of three with circumferential welds, two were tested in tension and one in torsion. In each specimen with a circumferential weld, a nonuniform axial distribution of strain was easily visible. The test results were compared to an existing empirical model of creep-rupture life. For the torsion test, the comparison was based on a definition of equivalent normal stress recently adopted in Code Case N-47. Some 27 fatigue specimens, with longitudinal, circumferential, or no welds, were tested under axial or torsional strain control. In specimens with welds, fatigue cracking initiated at fusion lines. In axial tests cracks grew in the circumferential direction, and in torsional tests cracks grew along fusion lines. The test results were compared to empirical models of fatigue life based on two definition of equivalent normal strain range. The results have provided some needed confirmation of the reduction factors for creep strength and fatigue life of modified 9 Cr-1 Mo steel weldments currently under consideration by ASME Code committees. 8 refs., 5 figs

Development of intra-strain self-cloning procedure for breeding baker's yeast strains.

Science.gov (United States)

Nakagawa, Youji; Ogihara, Hiroyuki; Mochizuki, Chisato; Yamamura, Hideki; Iimura, Yuzuru; Hayakawa, Masayuki

2017-03-01

Previously reported self-cloning procedures for breeding of industrial yeast strains require DNA from other strains, plasmid DNA, or mutagenesis. Therefore, we aimed to construct a self-cloning baker's yeast strain that exhibits freeze tolerance via an improved self-cloning procedure. We first disrupted the URA3 gene of a prototrophic baker's yeast strain without the use of any marker gene, resulting in a Δura3 homozygous disruptant. Then, the URA3 gene of the parental baker's yeast strain was used as a selection marker to introduce the constitutive TDH3 promoter upstream of the PDE2 gene encoding high-affinity cyclic AMP phosphodiesterase. This self-cloning procedure was performed without using DNA from other Saccharomyces cerevisiae strains, plasmid DNA, or mutagenesis and was therefore designated an intra-strain self-cloning procedure. Using this self-cloning procedure, we succeeded in producing self-cloning baker's yeast strains that harbor the TDH3p-PDE2 gene heterozygously and homozygously, designated TDH3p-PDE2 hetero and TDH3p-PDE2 homo strains, respectively. These self-cloning strains expressed much higher levels of PDE2 mRNA than the parental strain and exhibited higher viability after freeze stress, as well as higher fermentation ability in frozen dough, when compared with the parental strain. The TDH3p-PDE2 homo strain was genetically more stable than the TDH3p-PDE2 hetero strain. These results indicate that both heterozygous and homozygous strains of self-cloning PDE2-overexpressing freeze-tolerant strains of industrial baker's yeast can be prepared using the intra-strain self-cloning procedure, and, from a practical viewpoint, the TDH3p-PDE2 homo strain constructed in this study is preferable to the TDH3p-PDE2 hetero strain for frozen dough baking. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Methods for the enzymatic modification of steviol glycosides, modified steviol glycosides obtainable thereby, and the use thereof as sweeteners

NARCIS (Netherlands)

te Poele, Evelien; Dijkhuizen, Lubbert; Gerwig, Gerrit; Kamerling, Johannis

2016-01-01

The present invention relates generally to the production of steviol glycosides. Provided is a method for enzymatically providing a modified steviol glycoside, comprising incubating a steviol glycoside substrate in the presence of sucrose and the glucansucrase GTF180 of Lactobacillus reuteri strain

The influence of gender-specific loading patterns of the stop-jump task on anterior cruciate ligament strain.

Science.gov (United States)

Weinhold, Paul S; Stewart, Jason-Dennis N; Liu, Hsin-Yi; Lin, Cheng-Feng; Garrett, William E; Yu, Bing

2007-08-01

Studies have shown that women are at higher risk of sustaining noncontact anterior cruciate ligament (ACL) injuries in specific sports. Recent gait studies of athletic tasks have documented that gender differences in knee movement, muscle activation, and external loading patterns exist. The objective of this study was to determine in a knee cadaver model if application of female-specific loading and movement patterns characterised in vivo for a stop-jump task cause higher ACL strains than male patterns. Gender-specific loading patterns of the landing phase of the vertical stop-jump task were applied to seven cadaver knees using published kinetic/kinematic results for recreational athletes. Loads applied consecutively included: tibial compression, quadriceps, hamstrings, external posterior tibial shear, and tibial torque. Knee flexion was fixed based on the kinematic data. Strain of the ACL was monitored by means of a differential variable reluctance transducer installed on the anterior-medial bundle of the ACL. The ACL strain was significantly increased (P<0.05) for the female loading pattern relative to the male loading pattern after the posterior tibial shear force was applied, and showed a similar trend (P=0.1) to be increased after the final tibial torque was applied. This study suggests that female motor control strategies used during the stop-jump task may place higher strains on the ACL than male strategies, thus putting females at greater risk of ACL injury. We believe these results suggest the potential effectiveness of using training programs to modify motor control strategies and thus modify the risk of injury.

Magnetic separation of algae genetically modified for increased intracellular iron uptake

Energy Technology Data Exchange (ETDEWEB)

Buck, Amy [Case Western Reserve University, Cleveland, OH (United States); Cleveland Clinic, Cleveland, OH (United States); Moore, Lee R. [Cleveland Clinic, Cleveland, OH (United States); Lane, Christopher D.; Kumar, Anil; Stroff, Clayton; White, Nicolas [Phycal Inc., Cleveland, OH (United States); Xue, Wei; Chalmers, Jeffrey J. [The Ohio State University, Columbus, OH (United States); Zborowski, Maciej, E-mail: zborowm@ccf.org [Cleveland Clinic, Cleveland, OH (United States)

2015-04-15

Algae were investigated in the past as a potential source of biofuel and other useful chemical derivatives. Magnetic separation of algae by iron oxide nanoparticle binding to cells has been proposed by others for dewatering of cellular mass prior to lipid extraction. We have investigated feasibility of magnetic separation based on the presence of natural iron stores in the cell, such as the ferritin in Auxenochlorella protothecoides (A. protothecoides) strains. The A. protothecoides cell constructs were tested for inserted genes and for increased intracellular iron concentration by inductively coupled plasma atomic absorption (ICP–AA). They were grown in Sueoka’s modified high salt media with added vitamin B1 and increasing concentration of soluble iron compound (FeCl{sub 3} EDTA, from 1× to 8× compared to baseline). The cell magnetic separation conditions were tested using a thin rectangular flow channel pressed against interpolar gaps of a permanent magnet forming a separation system of a well-defined fluid flow and magnetic fringing field geometry (up to 2.2 T and 1000 T/m) dubbed “magnetic deposition microscopy”, or MDM. The presence of magnetic cells in suspension was detected by formation of characteristic deposition bands at the edges of the magnet interpolar gaps, amenable to optical scanning and microscopic examination. The results demonstrated increasing cellular Fe uptake with increasing Fe concentration in the culture media in wild type strain and in selected genetically-modified constructs, leading to magnetic separation without magnetic particle binding. The throughput in this study is not sufficient for an economical scale harvest. - Highlights: • Auxenochlorella protothecoides algae were genetically modified for biofuel production. • Algal iron metabolism was sufficient for their label-less magnetic separation. • High magnetic field and low flow required make the separation scale-up uneconomical.

Magnetic separation of algae genetically modified for increased intracellular iron uptake

International Nuclear Information System (INIS)

Buck, Amy; Moore, Lee R.; Lane, Christopher D.; Kumar, Anil; Stroff, Clayton; White, Nicolas; Xue, Wei; Chalmers, Jeffrey J.; Zborowski, Maciej

2015-01-01

Algae were investigated in the past as a potential source of biofuel and other useful chemical derivatives. Magnetic separation of algae by iron oxide nanoparticle binding to cells has been proposed by others for dewatering of cellular mass prior to lipid extraction. We have investigated feasibility of magnetic separation based on the presence of natural iron stores in the cell, such as the ferritin in Auxenochlorella protothecoides (A. protothecoides) strains. The A. protothecoides cell constructs were tested for inserted genes and for increased intracellular iron concentration by inductively coupled plasma atomic absorption (ICP–AA). They were grown in Sueoka’s modified high salt media with added vitamin B1 and increasing concentration of soluble iron compound (FeCl 3 EDTA, from 1× to 8× compared to baseline). The cell magnetic separation conditions were tested using a thin rectangular flow channel pressed against interpolar gaps of a permanent magnet forming a separation system of a well-defined fluid flow and magnetic fringing field geometry (up to 2.2 T and 1000 T/m) dubbed “magnetic deposition microscopy”, or MDM. The presence of magnetic cells in suspension was detected by formation of characteristic deposition bands at the edges of the magnet interpolar gaps, amenable to optical scanning and microscopic examination. The results demonstrated increasing cellular Fe uptake with increasing Fe concentration in the culture media in wild type strain and in selected genetically-modified constructs, leading to magnetic separation without magnetic particle binding. The throughput in this study is not sufficient for an economical scale harvest. - Highlights: • Auxenochlorella protothecoides algae were genetically modified for biofuel production. • Algal iron metabolism was sufficient for their label-less magnetic separation. • High magnetic field and low flow required make the separation scale-up uneconomical

Study of modifiers factors associated to mitochondrial mutations in individuals with hearing impairment

International Nuclear Information System (INIS)

Sousa de Moraes, Vanessa Cristine; Alexandrino, Fabiana; Andrade, Paula Baloni; Camara, Marilia Fontenele; Sartorato, Edi Lucia

2009-01-01

Hearing impairment is the most prevalent sensorial deficit in the general population. Congenital deafness occurs in about 1 in 1000 live births, of which approximately 50% has hereditary cause in development countries. Non-syndromic deafness can be caused by mutations in both nuclear and mitochondrial genes. Mutations in mtDNA have been associated with aminoglycoside-induced and non-syndromic deafness in many families worldwide. However, the nuclear background influences the phenotypic expression of these pathogenic mutations. Indeed, it has been proposed that nuclear modifier genes modulate the phenotypic manifestation of the mitochondrial A1555G mutation in the MTRNR1 gene. The both putative nuclear modifiers genes TRMU and MTO1 encoding a highly conserved mitochondrial related to tRNA modification. It has been hypothesizes that human TRMU and also MTO1 nuclear genes may modulate the phenotypic manifestation of deafness-associated mitochondrial mutations. The aim of this work was to elucidate the contribution of mitochondrial mutations, nuclear modifier genes mutations and aminoglycoside exposure in the deafness phenotype. Our findings suggest that the genetic background of individuals may play an important role in the pathogenesis of deafness-associated with mitochondrial mutation and aminoglycoside-induced.

Microstructure and strain-stress analysis of the dynamic strain aging in inconel 625 at high temperature

Science.gov (United States)

Maj, P.; Zdunek, J.; Mizera, J.; Kurzydlowski, K. J.; Sakowicz, B.; Kaminski, M.

2017-01-01

Serrated flow is a result of unstable plastic flow, which occurs during tensile and compression tests on some dilute alloys. This phenomenon is referred as the Portevin Le-Chatelier effect (PLC effect). The aim of this research was to investigate and analyze this phenomenon in Inconel 625 solution strengthened superalloy. The tested material was subjected to tensile tests carried out within the temperature range 200-700 °C, with three different strain rates: 0.002 1/s, 0.01/s, and 0.05 1/s and additional compression tests with high deformation speeds of 0.1, 1, and 10 1/s. The tensile strain curves were analyzed in terms of intensity and the observed patterns of serrations Using a modified stress drop method proposed by the authors, the activation energy was calculated with the assumption that the stress drops' distribution is a direct representation of an average solute atom's interaction with dislocations. Subsequently, two models, the standard vacancy diffusion Bilby-Cottrell model and the realistic cross-core diffusion mechanism proposed by Zhang and Curtin, were compared. The results obtained show that the second one agrees with the experimental data. Additional microstructure analysis was performed to identify microstructure elements that may be responsible for the PLC effect. Based on the results, the relationship between the intensity of the phenomenon and the conditions of the tests were determined.

Research on non-uniform strain profile reconstruction along fiber Bragg grating via genetic programming algorithm and interrelated experimental verification

Science.gov (United States)

Zheng, Shijie; Zhang, Nan; Xia, Yanjun; Wang, Hongtao

2014-03-01

A new heuristic strategy for the non-uniform strain profile reconstruction along Fiber Bragg Gratings is proposed in this paper, which is based on the modified transfer matrix and Genetic Programming(GP) algorithm. The present method uses Genetic Programming to determine the applied strain field as a function of position along the fiber length. The structures that undergo adaptation in genetic programming are hierarchical structures which are different from that of conventional genetic algorithm operating on strings. GP regress the strain profile function which matches the 'measured' spectrum best and makes space resolution of strain reconstruction arbitrarily high, or even infinite. This paper also presents an experimental verification of the reconstruction of non-homogeneous strain fields using GP. The results are compared with numerical calculations of finite element method. Both the simulation examples and experimental results demonstrate that Genetic Programming can effectively reconstruct continuous profile expression along the whole FBG, and greatly improves its computational efficiency and accuracy.

A statistical assessment of differences and equivalences between genetically modified and reference plant varieties

NARCIS (Netherlands)

Voet, van der H.; Perry, J.N.; Amzal, B.; Paoletti, C.

2011-01-01

Background - Safety assessment of genetically modified organisms is currently often performed by comparative evaluation. However, natural variation of plant characteristics between commercial varieties is usually not considered explicitly in the statistical computations underlying the assessment.

Perpendicular magnetic tunnel junction with a strained Mn-based nanolayer

Science.gov (United States)

Suzuki, K. Z.; Ranjbar, R.; Okabayashi, J.; Miura, Y.; Sugihara, A.; Tsuchiura, H.; Mizukami, S.

2016-07-01

A magnetic tunnel junction with a perpendicular magnetic easy-axis (p-MTJ) is a key device for spintronic non-volatile magnetoresistive random access memory (MRAM). Co-Fe-B alloy-based p-MTJs are being developed, although they have a large magnetisation and medium perpendicular magnetic anisotropy (PMA), which make it difficult to apply them to a future dense MRAM. Here, we demonstrate a p-MTJ with an epitaxially strained MnGa nanolayer grown on a unique CoGa buffer material, which exhibits a large PMA of more than 5 Merg/cm3 and magnetisation below 500 emu/cm3 these properties are sufficient for application to advanced MRAM. Although the experimental tunnel magnetoresistance (TMR) ratio is still low, first principles calculations confirm that the strain-induced crystal lattice distortion modifies the band dispersion along the tetragonal c-axis into the fully spin-polarised state; thus, a huge TMR effect can be generated in this p-MTJ.

Associations between Potentially Modifiable Risk Factors and Alzheimer Disease : A Mendelian Randomization Study

NARCIS (Netherlands)

Ostergaard, Soren D.; Mukherjee, Shubhabrata; Sharp, Stephen J.; Proitsi, Petroula; Lotta, Luca A.; Day, Felix; Perry, John R. B.; Boehme, Kevin L.; Walter, Stefan; Kauwe, John S.; Gibbons, Laura E.; Larson, Eric B.; Powell, John F.; Langenberg, Claudia; Crane, Paul K.; Wareham, Nicholas J.; Scott, Robert A.; van der Schouw, YT

Background Potentially modifiable risk factors including obesity, diabetes, hypertension, and smoking are associated with Alzheimer disease (AD) and represent promising targets for intervention. However, the causality of these associations is unclear. We sought to assess the causal nature of these

Effect of chemical pressure, misfit strain and hydrostatic pressure on structural and magnetic behaviors of rare-earth orthochromates

International Nuclear Information System (INIS)

Zhao, Hong Jian; Chen, Xiang Ming; Ren, Wei; Bellaiche, L

2013-01-01

First-principles calculations are performed to investigate structural and magnetic behaviors of rare-earth orthochromates as a function of ‘chemical’ pressure (that is, the rare-earth ionic radius), epitaxial misfit strain and hydrostatic pressure. From a structural point of view, (i) ‘chemical’ pressure significantly modifies antipolar displacements, Cr–O–Cr bond angles and the resulting oxygen octahedral tiltings; (ii) hydrostatic pressure mostly changes Cr–O bond lengths; and (iii) misfit strain affects all these quantities. The correlations between magnetic properties (Néel temperature and weak ferromagnetic moments) and unit cell volume are similar when varying the misfit strain or hydrostatic pressure, but differ from those associated with the ‘chemical’ pressure. Origins of such effects are also discussed. (paper)

Establishment of Lactobacillus plantarum strain in honey bee digestive tract monitored using gfp fluorescence.

Science.gov (United States)

Javorský, P; Fecskeová, L Kolesár; Hrehová, L; Sabo, R; Legáth, J; Pristas, P

2017-04-26

Lactic acid bacteria are symbiotic bacteria that naturally reside in the gastrointestinal tract of honey bees. They serve a multitude of functions and are considered beneficial and completely harmless. In our experiments Lactobacillus plantarum strain B35, isolated from honey bee digestive tract, was modified using pAD43-25 plasmid carrying a functional GFP gene sequence (gfpmut3a) and used as a model for monitoring and optimisation of the mode of application. The establishment of this strain in honey bee digestive tract was monitored using GFP fluorescence. Three different modes of oral application of this strain were tested: water suspension of lyophilised bacteria, aerosol application of these bacteria and consumption of sugar honey paste containing the lyophilised lactobacilli. Two days after administration the L. plantarum B35-gfp was present throughout the honey bee digestive tract with 10 4 -10 5 cfu/bee with highest count observed for aerosol application.

Modified resistivity-strain behavior through the incorporation of metallic particles in conductive polymer composite fibers containing carbon nanotubes

NARCIS (Netherlands)

Lin, L.; Deng, H.; Gao, X.; Zhang, S.M.; Bilotti, E.; Peijs, A.A.J.M.; Fu, Q.

2013-01-01

Eutectic metal particles and carbon nanotubes are incorporated into a thermoplastic polyurethane matrix through a simple but efficient method, melt compounding, to tune the resistivity-strain behavior of conductive polymer composite (CPC) fibers. Such a combination of conductive fillers is rarely