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Sample records for strain adp effects

  1. Complete Nucleotide Sequence and Organization of the Atrazine Catabolic Plasmid pADP-1 from Pseudomonas sp. Strain ADP

    Science.gov (United States)

    Martinez, Betsy; Tomkins, Jeffrey; Wackett, Lawrence P.; Wing, Rod; Sadowsky, Michael J.

    2001-01-01

    The complete 108,845-nucleotide sequence of catabolic plasmid pADP-1 from Pseudomonas sp. strain ADP was determined. Plasmid pADP-1 was previously shown to encode AtzA, AtzB, and AtzC, which catalyze the sequential hydrolytic removal of s-triazine ring substituents from the herbicide atrazine to yield cyanuric acid. Computational analyses indicated that pADP-1 encodes 104 putative open reading frames (ORFs), which are predicted to function in catabolism, transposition, and plasmid maintenance, transfer, and replication. Regions encoding transfer and replication functions of pADP-1 had 80 to 100% amino acid sequence identity to pR751, an IncPβ plasmid previously isolated from Enterobacter aerogenes. pADP-1 was shown to contain a functional mercury resistance operon with 99% identity to Tn5053. Complete copies of transposases with 99% amino acid sequence identity to TnpA from IS1071 and TnpA from Pseudomonas pseudoalcaligenes were identified and flank each of the atzA, atzB, and atzC genes, forming structures resembling nested catabolic transposons. Functional analyses identified three new catabolic genes, atzD, atzE, and atzF, which participate in atrazine catabolism. Crude extracts from Escherichia coli expressing AtzD hydrolyzed cyanuric acid to biuret. AtzD showed 58% amino acid sequence identity to TrzD, a cyanuric acid amidohydrolase, from Pseudomonas sp. strain NRRLB-12227. Two other genes encoding the further catabolism of cyanuric acid, atzE and atzF, reside in a contiguous cluster adjacent to a potential LysR-type transcriptional regulator. E. coli strains bearing atzE and atzF were shown to encode a biuret hydrolase and allophanate hydrolase, respectively. atzDEF are cotranscribed. AtzE and AtzF are members of a common amidase protein family. These data reveal the complete structure of a catabolic plasmid and show that the atrazine catabolic genes are dispersed on three disparate regions of the plasmid. These results begin to provide insight into how

  2. The Multiple Effect of Agricultural Development Programme's (ADP's ...

    African Journals Online (AJOL)

    This paper determined the multiplier effects of the use of Small Plot Adoption Technique (SPAT) by the Abia ADP on the income of Smallholder farmers in Abia State. The choice of Abia ADP for this research was purposive. A multi-stage random sampling technique was used in the selection of blocks, circles, 300 contact ...

  3. Ageing of atrazine in manure amended soils assessed by bioavailability to Pseudomonas sp. strain ADP

    DEFF Research Database (Denmark)

    Glæsner, Nadia; Bælum, Jacob; Strobel, Bjarne W.

    2014-01-01

    bacteria Pseudomonas sp. strain ADP. Throughout an ageing period of 90 days bioavailability was investigated at days 1, 10, 32, 60 and 90, where ~108 cells g−1 of the ADP strain was inoculated to the 14C-atrazine exposed soil and 14CO2 was collected over 7 days as a measure of mineralized atrazine. Even...... though the bioavailable residue decreased in all of the three soils as time proceeded, we found that ageing occurred faster in the topsoils rich in organic carbon than in subsoil. For one topsoil rich in organic carbon content, Simmelkær, we observed a higher degree of ageing when treated with manure....... Contrarily, sorption experiments showed less sorption to Simmelkær treated with manure than the untreated soil indicating that sorption processes are not the only mechanisms of ageing. The other topsoil low in organic carbon content, Ringe, showed no significant difference in ageing between the manure...

  4. Purification and Characterization of Allophanate Hydrolase (AtzF) from Pseudomonas sp. Strain ADP

    Science.gov (United States)

    Shapir, Nir; Sadowsky, Michael J.; Wackett, Lawrence P.

    2005-01-01

    AtzF, allophanate hydrolase, is a recently discovered member of the amidase signature family that catalyzes the terminal reaction during metabolism of s-triazine ring compounds by bacteria. In the present study, the atzF gene from Pseudomonas sp. strain ADP was cloned and expressed as a His-tagged protein, and the protein was purified and characterized. AtzF had a deduced subunit molecular mass of 66,223, based on the gene sequence, and an estimated holoenzyme molecular mass of 260,000. The active protein did not contain detectable metals or organic cofactors. Purified AtzF hydrolyzed allophanate with a kcat/Km of 1.1 × 104 s−1 M−1, and 2 mol of ammonia was released per mol allophanate. The substrate range of AtzF was very narrow. Urea, biuret, hydroxyurea, methylcarbamate, and other structurally analogous compounds were not substrates for AtzF. Only malonamate, which strongly inhibited allophanate hydrolysis, was an alternative substrate, with a greatly reduced kcat/Km of 21 s−1 M−1. Data suggested that the AtzF catalytic cycle proceeds through a covalent substrate-enzyme intermediate. AtzF reacts with malonamate and hydroxylamine to generate malonohydroxamate, potentially derived from hydroxylamine capture of an enzyme-tethered acyl group. Three putative catalytically important residues, one lysine and two serines, were altered by site-directed mutagenesis, each with complete loss of enzyme activity. The identity of a putative serine nucleophile was probed using phenyl phosphorodiamidate that was shown to be a time-dependent inhibitor of AtzF. Inhibition was due to phosphoroamidation of Ser189 as shown by liquid chromatography/matrix-assisted laser desorption ionization mass spectrometry. The modified residue corresponds in sequence alignments to the nucleophilic serine previously identified in other members of the amidase signature family. Thus, AtzF affects the cleavage of three carbon-to-nitrogen bonds via a mechanism similar to that of enzymes

  5. Inhibitory effect of novel pyrimidines on ATP and ADP hydrolysis in synaptosomes from rat cerebral cortex.

    Science.gov (United States)

    Cechin, Sirlene R; Schetinger, Maria Rosa C; Zanatta, Nilo; Madruga, Claudia C; Pacholski, Iraci L; Flores, Darlene C; Bonacorso, Helio G; Martins, Marcos A P; Morsch, Vera M

    2003-11-01

    In this study, a new series of trihalomethyl-substituted pyrimidines and dihydropyrimidines were synthesized and tested as potential NTPDase inhibitors. For this purpose, synaptosomes from rat cerebral cortex were used as the enzyme source and ATP and ADP were used as the substrate. Among the new compounds, 4-methyl-2-methylsulfanyl-6-trichloromethylpyrimidine (2b) was found to be the most effective noncompetitive inhibitor, with an estimated K(i) value of 0.18 and 0.55 mM for ATP and ADP, respectively. Other pyrimidines inhibited NTPDase activity with the following rank order of inhibitory potency: 3,6-dimethyl-2-methylsulfanyl-4-trifluoromethyl-3,4-dihydro-pyrimidin-4-ol (3a) > 5-methyl-2-(4-methyl-6-trifluoromethyl-pyrimidin-2-yl)-3-trifluoromethyl-3,4-dihydro-2H-3-pyrazol-3-ol (6a) > 5-bromo-4,6-dimethoxy-4-trichloromethyl-1,2,3,4-tetrahydro-2-pyrimidin-2-one (9) for ATP and 6a > 9 > 3a for ADP. Our results demonstrate that a novel group of pyrimidines compounds can act as inhibitors of ATP and ADP hydrolysis in synaptosomes from rat cerebral cortex. These results can contribute for the understanding of the NTPDase activity and for further studies involving new compounds that can enlist as it inhibitors.

  6. Interaction of Prevotella intermedia strain 17 leucine-rich repeat domain protein AdpF with eukaryotic cells promotes bacterial internalization.

    Science.gov (United States)

    Sengupta, Dipanwita; Kang, Dae-Joong; Anaya-Bergman, Cecilia; Wyant, Tiana; Ghosh, Arnab K; Miyazaki, Hiroshi; Lewis, Janina P

    2014-06-01

    Prevotella intermedia is an oral bacterium implicated in a variety of oral diseases. Although internalization of this bacterium by nonphagocytic host cells is well established, the molecular players mediating the process are not well known. Here, the properties of a leucine-rich repeat (LRR) domain protein, designated AdpF, are described. This protein contains a leucine-rich region composed of 663 amino acid residues, and molecular modeling shows that it folds into a classical curved solenoid structure. The cell surface localization of recombinant AdpF (rAdpF) was confirmed by electron and confocal microscopy analyses. The recombinant form of this protein bound fibronectin in a dose-dependent manner. Furthermore, the protein was internalized by host cells, with the majority of the process accomplished within 30 min. The internalization of rAdpF was inhibited by nystatin, cytochalasin, latrunculin, nocodazole, and wortmannin, indicating that microtubules, microfilaments, and signal transduction are required for the invasion. It is noteworthy that preincubation of eukaryotic cells with AdpF increased P. intermedia 17 internalization by 5- and 10-fold for HeLa and NIH 3T3 fibroblast cell lines, respectively. The addition of the rAdpF protein was also very effective in inducing bacterial internalization into the oral epithelial cell line HN4, as well as into primary cells, including human oral keratinocytes (HOKs) and human umbilical vein endothelial cells (HUVECs). Finally, cells exposed to P. intermedia 17 internalized the bacteria more readily upon reinfection. Taken together, our data demonstrate that rAdpF plays a role in the internalization of P. intermedia 17 by a variety of host cells.

  7. Effect of oxalic acid on the optical, thermal, dielectric and mechanical behaviour of ADP crystals

    International Nuclear Information System (INIS)

    Rajesh, P.; Ramasamy, P.

    2009-01-01

    The effect of the addition, over a concentration range from 1 to 5 mol%, of oxalic acid on the growth rate, optical transparency, hardness, dielectric behaviour, and SHG efficiency of ammonium dihydrogen phosphate single crystals grown by slow evaporation method has been investigated. UV-Vis studies show that the transparency of the oxalic acid added crystals decreased gradually. Thermal studies indicate that the decomposition temperatures of the crystal are decreased in oxalic acid added ADP crystals. It is observed from the dielectric measurements that the dielectric constant and dielectric loss increase with increase in temperature for all the crystals. Vicker's microhardness study reveals that the addition of higher concentration of oxalic acid decreases the hardness of the crystal. SHG efficiency of 1 mol% of oxalic acid is higher than the pure ADP.

  8. Differential effects of adenine nucleotide analogues on shape change and aggregation induced by adnosine 5-diphosphate (ADP) in human platelets.

    Science.gov (United States)

    Park, H S; Hourani, S M

    1999-07-01

    Adenosine 5'-diphosphate (ADP) induces human blood platelets to aggregate and change shape, and it has been suggested that these two responses are mediated by more than one subtype of ADP receptor. The structure-activity relationships for several analogues of adenine nucleotides in causing aggregation and shape change were measured and compared in washed platelets using an aggregometer. ADP and its analogues 2-methylthioadenosine 5'-diphosphate (2-methylthio-ADP), adenosine 5'(alpha,beta-methylene)diphosphonate (AMPCP), S(P)-adenosine 5'-O-(1-thiodiphosphate) (AD-P alphaS) and adenosine 5'-O-(2-thiodiphosphate) (ADPbetaS) were used as agonists. Adenosine 5'-triphosphate (ATP) and its analogues, P1, P5-diadenosine pentaphosphate (ApsA), adenosine (5'-(alpha,beta-methylene)triphosphonate (AMPCPP), 2-methylthioadenosine 5'-triphosphate (2-methylthio-ATP) and uridine 5'-triphosphate (UTP), as well as the trypanocidal drug suramin, were used as antagonists. In general, the structure-activity relationships for both responses were similar, but for some analogues differences were observed. ADPalphaS and ADPbetaS were much more potent agonists relative to ADP for shape change than for aggregation and indeed ADPalphaS antagonized ADP-induced aggregation with an apparent pK(B) value of 5.5+/-0.1. 2-Methylthio-ATP also had different effects in aggregation and shape change, being a much higher affinity antagonist of aggregation than of shape change with an apparent pK(B) value of 7.0+/-0.2 for aggregation and 5.2+/-0.2 for shape change. These results support the suggestion that these two responses are mediated by multiple ADP receptors on human platelets, and are consistent with shape change being mediated via one receptor (the P2Y1 receptor) with aggregation requiring the activation of two receptors (the P2Y1 and another P2Y receptor).

  9. Cloning and genetic characterization of dca genes required for beta-oxidation of straight-chain dicarboxylic acids in Acinetobacter sp. strain ADP1.

    Science.gov (United States)

    Parke, D; Garcia, M A; Ornston, L N

    2001-10-01

    A previous study of deletions in the protocatechuate (pca) region of the Acinetobacter sp. strain ADP1 chromosome revealed that genes required for utilization of the six-carbon dicarboxylic acid, adipic acid, are linked to the pca structural genes. To investigate the genes involved in adipate catabolism, a 33.8-kb SacI fragment, which corrects a deletion spanning this region, was cloned. In addition to containing known pca, qui, and pob genes (for protocatechuate, quinate, and 4-hydroxybenzoate dissimilation), clone pZR8000 contained 10 kb of DNA which was the subject of this investigation. A mutant strain of Escherichia coli DH5alpha, strain EDP1, was isolated that was able to utilize protocatechuate and 4-hydroxybenzoate as growth substrates when EDP1 cells contained pZR8000. Sequence analysis of the new region of DNA on pZR8000 revealed open reading frames predicted to be involved in beta-oxidation. Knockouts of three genes implicated in beta-oxidation steps were introduced into the chromosome of Acinetobacter sp. strain ADP1. Each of the mutants was unable to grow with adipate. Because the mutants were affected in their ability to utilize additional saturated, straight-chain dicarboxylic acids, the newly discovered 10 kb of DNA was termed the dca (dicarboxylic acid) region. Mutant strains included one with a deletion in dcaA (encoding an acyl coenzyme A [acyl-CoA] dehydrogenase homolog), one with a deletion in dcaE (encoding an enoyl-CoA hydratase homolog), and one with a deletion in dcaH (encoding a hydroxyacyl-CoA dehydrogenase homolog). Data on the dca region should help us probe the functional significance and interrelationships of clustered genetic elements in this section of the Acinetobacter chromosome.

  10. Effects of epinephrine on ADP-induced changes in platelet inositol phosphates

    International Nuclear Information System (INIS)

    Vickers, J.D.; Keraly, C.L.; Kinlough-Rathbone, R.L.; Mustard, J.F.

    1986-01-01

    Epinephrine (EPI) does not aggregate rabbit platelets, but it does increase the labelling of inositol phosphate (IP) at 60s (21%, p + , in platelets prelabelled with [ 3 H] inositol. In contrast, 0.5 μM ADP which causes aggregation, increases the labelling of inositol bisphosphate (IP 2 ) by 30% (p 2 by 154% (p 2 stimulated by ADP + EPI was greater than the increase caused by ADP (p 2 due to 0.2 μM ADP + 0.6 μM EPI by 70% (p 2 by 108% (0 2 metabolism stimulated via the α-adrenergic receptor

  11. Endothermic force generation, temperature-jump experiments and effects of increased [MgADP] in rabbit psoas muscle fibres.

    Science.gov (United States)

    Coupland, M E; Pinniger, G J; Ranatunga, K W

    2005-09-01

    We studied, by experiment and by kinetic modelling, the characteristics of the force increase on heating (endothermic force) in muscle. Experiments were done on maximally Ca2+-activated, permeabilized, single fibres (length approximately 2 mm; sarcomere length, 2.5 microm) from rabbit psoas muscle; [MgATP] was 4.6 mM, pH 7.1 and ionic strength was 200 mM. A small-amplitude (approximately 3 degrees C) rapid laser temperature-jump (0.2 ms T-jump) at 8-9 degrees C induced a tension rise to a new steady state and it consisted of two (fast and slow) exponential components. The T-jump-induced tension rise became slower as [MgADP] was increased, with half-maximal effect at 0.5 mM [MgADP]; the pre- and post-T-jump tension increased approximately 20% with 4 mM added [MgADP]. As determined by the tension change to small, rapid length steps (<1.4%L0 complete in <0.5 ms), the increase of force by [MgADP] was not associated with a concomitant increase of stiffness; the quick tension recovery after length steps (Huxley-Simmons phase 2) was slower with added MgADP. In steady-state experiments, the tension was larger at higher temperatures and the plot of tension versus reciprocal absolute temperature was sigmoidal, with a half-maximal tension at 10-12 degrees C; the relation with added 4 mM MgADP was shifted upwards on the tension axis and towards lower temperatures. The potentiation of tension with 4 mM added MgADP was 20-25% at low temperatures (approximately 5-10 degrees C), but approximately 10% at the physiological temperatures (approximately 30 degrees C). The shortening velocity was decreased with increased [MgADP] at low and high temperatures. The sigmoidal relation between tension and reciprocal temperature, and the basic effects of increased [MgADP] on endothermic force, can be qualitatively simulated using a five-step kinetic scheme for the crossbridge/A-MATPase cycle where the force generating conformational change occurs in a reversible step before the release of

  12. Novel cholix toxin variants, ADP-ribosylating toxins in Vibrio cholerae non-O1/non-O139 strains, and their pathogenicity.

    Science.gov (United States)

    Awasthi, Sharda Prasad; Asakura, Masahiro; Chowdhury, Nityananda; Neogi, Sucharit Basu; Hinenoya, Atsushi; Golbar, Hossain M; Yamate, Jyoji; Arakawa, Eiji; Tada, Toshiji; Ramamurthy, T; Yamasaki, Shinji

    2013-02-01

    Cholix toxin (ChxA) is a recently discovered exotoxin in Vibrio cholerae which has been characterized as a third member of the eukaryotic elongation factor 2-specific ADP-ribosyltransferase toxins, in addition to exotoxin A of Pseudomonas aeruginosa and diphtheria toxin of Corynebacterium diphtheriae. These toxins consist of three characteristic domains for receptor binding, translocation, and catalysis. However, there is little information about the prevalence of chxA and its genetic variations and pathogenic mechanisms. In this study, we screened the chxA gene in a large number (n = 765) of V. cholerae strains and observed its presence exclusively in non-O1/non-O139 strains (27.0%; 53 of 196) and not in O1 (n = 485) or O139 (n = 84). Sequencing of these 53 chxA genes generated 29 subtypes which were grouped into three clusters designated chxA I, chxA II, and chxA III. chxA I belongs to the prototype, while chxA II and chxA III are newly discovered variants. ChxA II and ChxA III had unique receptor binding and catalytic domains, respectively, in comparison to ChxA I. Recombinant ChxA I (rChxA I) and rChxA II but not rChxA III showed variable cytotoxic effects on different eukaryotic cells. Although rChxA II was more lethal to mice than rChxA I when injected intravenously, no enterotoxicity of any rChxA was observed in a rabbit ileal loop test. Hepatocytes showed coagulation necrosis in rChxA I- or rChxA II-treated mice, seemingly the major target for ChxA. The present study illustrates the potential of ChxA as an important virulence factor in non-O1/non-O139 V. cholerae, which may be associated with extraintestinal infections rather than enterotoxicity.

  13. Modulation of ATP/ADP concentration at the endothelial surface by shear stress: effect of flow recirculation.

    Science.gov (United States)

    Choi, Hyo Won; Ferrara, Katherine W; Barakat, Abdul I

    2007-04-01

    The extracellular presence of the adenine nucleotides ATP and ADP induces calcium mobilization in vascular endothelial cells (ECs). ATP/ADP concentration at the EC surface is determined by a balance of convective-diffusive transport to and from the EC surface, hydrolysis by ectonucleotidases at the cell surface, and flow-induced ATP release from ECs. Our previous numerical simulations in a parallel plate geometry had demonstrated that flow-induced ATP release has a profound effect on nucleotide concentration at the EC surface. In the present study, we have extended the modeling to probe the impact of flow separation and recirculation downstream of a backward facing step (BFS) on ATP/ADP concentration at the EC surface. The results show that for both steady and pulsatile flow over a wide range of wall shear stresses, the ATP+ADP concentration at the EC surface is considerably lower within the flow recirculation region than in areas of undisturbed flow outside the recirculation zone. Pulsatile flow also leads to sharp temporal gradients in nucleotide concentration. If confirmed experimentally, the present findings suggest that disturbed and undisturbed flow may affect EC calcium mobilization differently. Such differences might, in turn, contribute to the observed endothelial dysfunction in regions of disturbed flow.

  14. Prostaglandin E1 potentiates the effects of P2Y12 blockade on ADP-mediated platelet aggregation in vitro: Insights using short thromboelastography.

    Science.gov (United States)

    Khanna, Vikram; Armstrong, Paul C J; Warner, Timothy D; Curzen, Nick

    2015-01-01

    In addition to adenosine diphosphate (ADP), a number of platelet function tests including the VerifyNow P2Y12 assay (VN-P2Y12) employ prostaglandin E1 (PGE1) to improve specificity for P2Y12 blockade by mitigating the contribution of the P2Y1 pathway on ADP-mediated platelet aggregation. Using short thromboelastography (s-TEG), we have previously shown that VN-P2Y12 overestimates the functional effect of clopidogrel in some individuals. We investigated whether PGE1 systematically increases the inhibitory effects of P2Y12 blockade on ADP-mediated platelet aggregation in an in vitro model. Using s-TEG, we measured ADP-induced platelet aggregation either in the presence or absence of PGE1 (11 or 22 nM) in blood samples taken from healthy volunteers pre-incubated with prasugrel active metabolite (PAM; 0, 1, 3 or 10 µM). Individually, both PGE1 (p < 0.02) and PAM (p < 0.0001) inhibited ADP-mediated platelet aggregation in a dose-dependent manner, as expected. Furthermore, inclusion of PGE1 augmented inhibition of ADP-mediated platelet aggregation in response to PAM (p < 0.02) in a dose-dependent manner such that a 10-fold higher dose of PAM was required to attain equivalent inhibition of ADP-mediated platelet aggregation to that achieved by 1 µM PAM in the presence of 11 nM PGE1. In conclusion, PGE1 potentiates the anti-aggregatory effects of P2Y12 blockade on ADP-mediated platelet aggregation. Assays that employ PGE1 with ADP may therefore overestimate therapeutic response to prasugrel in a proportion of individuals, potentially making them unsuitable candidates for guiding delivery of personalized antiplatelet therapy.

  15. Characterization of transducin from bovine retinal rod outer segments: mechanism and effects of cholera toxin-catalyzed adp-ribosylation

    Energy Technology Data Exchange (ETDEWEB)

    Navon, S.E.; Fung, B.K.K.

    1984-05-25

    Transducin, a guanine nucleotide-binding protein consisting of two subunits (T/sub ..cap alpha../ and T/sub ..beta gamma../), mediates the signal coupling between rhodopsin and a membrane-bound cyclic GMP phosphodiesterase in retinal rod outer segments. The T/sub ..cap alpha../ subunit is an activator of the phosphodiesterase, and the function of the T/sub ..beta gamma../ subunit is to physically link T/sub ..cap alpha../ with photolyzed rhodopsin. In this study, the mechanism of cholera toxin-catalyzed ADP-ribosylation of T/sub ..cap alpha../ has been examined in a reconstituted system consisting of purified transducin and stripped rod outer segment membranes. Limited proteolysis of the labeled T/sub ..cap alpha../ with trypsin indicated that the inserted ADP-ribose is located exclusively on a single proteolytic fragment with an apparent molecular weight of 23,000. Maximal incorporation of ADP-ribose was achieved when guanosine 5'-(..beta..,..gamma..-im ido)triphosphate (Gpp(NH)p) and T/sub ..beta gamma../ were present at concentrations equal to that of T/sub ..cap alpha../ and when rhodopsin was continuously irradiated with visible light in the 400-500 nm region. The stimulating effect of illumination was related to the direct interaction of the retinal chromophore with opsin. These findings strongly suggest that a transient protein complex consisting of T/sub ..cap alpha../xGpp(NH)p, T/sub ..beta gamma../, and a photointermediate of rhodopsin is the required substrate for cholera toxin. Single turnover kinetic measurements demonstrated that the ADP-ribosylation of T/sub ..cap alpha../ coincided with the appearance of a population of transducin molecules having a very slow rate of GTP hydrolysis. The hydrolysis rate of the bound GTP for this population was 1.1 x 10/sup -3//s, which was 22-fold slower than the rate for the unmodified transducin. 30 references, 9 figures, 1 table.

  16. Dielectric, thermal and mechanical properties of ADP doped PVA composites

    Science.gov (United States)

    Naik, Jagadish; Bhajantri, R. F.; Ravindrachary, V.; Rathod, Sunil G.; Sheela, T.; Naik, Ishwar

    2015-06-01

    Polymer composites of poly(vinyl alcohol) (PVA), doped with different concentrations of ammonium dihydrogen phosphate (ADP) has been prepared by solution casting. The formation of complexation between ADP and PVA was confirmed with the help of Fourier transforms infrared (FTIR) spectroscopy. Thermogravimetric analysis (TGA) shows thermal stability of the prepared composites. Impedance analyzer study revealed the increase in dielectric constant and loss with increase the ADP concentration and the strain rate of the prepared composites decreases with ADP concentration.

  17. Effects of the gelatin plasma substitutes Haemaccel, Plasmagel and Plasmion (Geloplasma) on collagen-, ADP- and adrenaline-induced aggregation of human platelets in vitro.

    Science.gov (United States)

    Stibbe, J; van der Plas, P M; Ong, G L; ten Hoor, F; Nauta, J; de Jong, D S; Krenning-Douma, E; Gomes, M

    1981-01-01

    The effect of some gelatin plasma substitutes (Haemaccel, plasmagel and Plasmion (Geloplasma), which are widely used in Europe) on collagen-, ADP- and adrenaline-induced platelet aggregation in human PRP in vitro was studied under controlled conditions (pH, electrolyte composition). Haemaccel inhibited these aggregations, both in citrated as well as in heparinised PRP, whereas they were enhanced by both Plasmagel and Plasmion as compared to the appropriate control. Increasing teh concentration of the inducer overcame the inhibition by Haemaccel. Haemaccel inhibited, while Plasmion enhanced 14C-serotonin release induced by collagen, ADP or adrenaline. Also in the presence of indomethacin (90 muM) Haemaccel inhibited aggregation induced by high concentrations of collagen and the primary aggregation induced by ADP and adrenaline, while Plasmion enhanced these aggregations induced by ADP and adrenaline, while Plasmion enhanced these aggregations. The inhibition by Haemaccel was not caused by binding of Ca2+ to haemaccel.

  18. Expression of human poly (ADP-ribose) polymerase 1 in Saccharomyces cerevisiae: Effect on survival, homologous recombination and identification of genes involved in intracellular localization

    Energy Technology Data Exchange (ETDEWEB)

    La Ferla, Marco; Mercatanti, Alberto; Rocchi, Giulia; Lodovichi, Samuele; Cervelli, Tiziana; Pignata, Luca [Yeast Genetics and Genomics, Institute of Clinical Physiology, National Council of Research (CNR), via Moruzzi 1, 56122 Pisa (Italy); Caligo, Maria Adelaide [Section of Genetic Oncology, University Hospital and University of Pisa, via Roma 57, 56125 Pisa (Italy); Galli, Alvaro, E-mail: alvaro.galli@ifc.cnr.it [Yeast Genetics and Genomics, Institute of Clinical Physiology, National Council of Research (CNR), via Moruzzi 1, 56122 Pisa (Italy)

    2015-04-15

    Highlights: • The human poly (ADP-ribose) polymerase 1 (PARP-1) gene affects growth and UV-induced homologous recombination in yeast. • PARP-1 chemical inhibition impacts yeast growth and UV-induced recombination. • A genome-wide screen identifies 99 yeast genes that suppress the growth defect inferred by PARP-1. • Bioinformatics analysis identifies 41 human orthologues that may have a role in PARP-1 intracellular localization. • The findings suggest that PARP-1 nuclear localization may affect the response to PARP inhibitors in cancer therapy. - Abstract: The poly (ADP-ribose) polymerase 1 (PARP-1) actively participates in a series of functions within the cell that include: mitosis, intracellular signaling, cell cycle regulation, transcription and DNA damage repair. Therefore, inhibition of PARP1 has a great potential for use in cancer therapy. As resistance to PARP inhibitors is starting to be observed in patients, thus the function of PARP-1 needs to be studied in depth in order to find new therapeutic targets. To gain more information on the PARP-1 activity, we expressed PARP-1 in yeast and investigated its effect on cell growth and UV induced homologous recombination. To identify candidate genes affecting PARP-1 activity and cellular localization, we also developed a yeast genome wide genetic screen. We found that PARP-1 strongly inhibited yeast growth, but when yeast was exposed to the PARP-1 inhibitor 6(5-H) phenantridinone (PHE), it recovered from the growth suppression. Moreover, we showed that PARP-1 produced PAR products in yeast and we demonstrated that PARP-1 reduced UV-induced homologous recombination. By genome wide screening, we identified 99 mutants that suppressed PARP-1 growth inhibition. Orthologues of human genes were found for 41 of these yeast genes. We determined whether the PARP-1 protein level was altered in strains which are deleted for the transcription regulator GAL3, the histone H1 gene HHO1, the HUL4 gene, the

  19. Effect of mild temperature shift on poly(ADP-ribose) and γH2AX levels in cultured cells

    Energy Technology Data Exchange (ETDEWEB)

    Yamashita, Sachiko [Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829 (Japan); Tanaka, Masakazu [Department of Microbiology, Kansai Medical University, 2-5-1 Shin-machi, Hirakata City, Osaka 573-1010 (Japan); Sato, Teruaki [Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829 (Japan); Ida, Chieri [Department of Applied Life Studies, College of Nagoya Women’s University, 3-40 Shioji-cho, Mizuho-ku, Nagoya-shi, Aichi 467-8610 (Japan); Ohta, Narumi; Hamada, Takashi; Uetsuki, Taichi; Nishi, Yoshisuke [Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829 (Japan); Moss, Joel [Cardiovascular and Pulmonary Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-1590 (United States); Miwa, Masanao, E-mail: m_miwa@nagahama-i-bio.ac.jp [Faculty of Bioscience, Nagahama Institute of Bio-Science and Technology, 1266 Tamura, Nagahama, Shiga 526-0829 (Japan)

    2016-08-05

    Poly (ADP-ribose) (PAR) is rapidly synthesized by PAR polymerases (PARPs) upon activation by DNA single- and double-strand breaks. In this study, we examined the quantitative amount of PAR in HeLa cells cultured within the physiological temperatures below 41 °C for verification of the effect of shifting-up or -down the temperature from 37.0 °C on the DNA breaks, whether the temperature-shift caused breaks that could be monitored by the level of PAR. While PAR level did not change significantly when HeLa cells were cultured at 33.5 °C or 37.0 °C, it was significantly increased 2- and 3-fold when cells were cultured for 12 h and 24 h, respectively, at 40.5 °C as compared to 37.0 °C. Similar to the results with HeLa cells, PAR level was increased 2-fold in CHO-K1 cells cultured at 40.5 °C for 24 h as compared to 37.0 °C. As the cellular levels of PAR polymerase1 (PARP1) and PAR glycohydrolase (PARG), a major degradation enzyme for PAR, did not seem to change significantly, this increase could be caused by activation of PARP1 by DNA strand breaks. In fact, γH2AX, claimed to be a marker of DNA double-strand breaks, was found in cell extracts of HeLa cells and CHO-K1 cells at elevated temperature vs. 37.0 °C, and these γH2AX signals were intensified in the presence of 3-aminobenzamide, a PARP inhibitor. The γH2AX immunohistochemistry results in HeLa cells were consistent with Western blot analyses. In HeLa cells, proliferation was significantly suppressed at 40.5 °C in 72 h-continuous cultures and decreased viabilities were also observed after 24–72 h at 40.5 °C. Flow cytometric analyses showed that the HeLa cells were arrested at G2/M after temperature shift-up to 40.5 °C. These physiological changes were potentiated in the presence of 3-aminobenzamide. Decrease in growth rates, increased cytotoxicity and G2/M arrest, were associated with the temperature-shift to 40.5 °C and are indirect evidence of DNA breaks. In addition to γH2AX

  20. Effect of mild temperature shift on poly(ADP-ribose) and γH2AX levels in cultured cells

    International Nuclear Information System (INIS)

    Yamashita, Sachiko; Tanaka, Masakazu; Sato, Teruaki; Ida, Chieri; Ohta, Narumi; Hamada, Takashi; Uetsuki, Taichi; Nishi, Yoshisuke; Moss, Joel; Miwa, Masanao

    2016-01-01

    Poly (ADP-ribose) (PAR) is rapidly synthesized by PAR polymerases (PARPs) upon activation by DNA single- and double-strand breaks. In this study, we examined the quantitative amount of PAR in HeLa cells cultured within the physiological temperatures below 41 °C for verification of the effect of shifting-up or -down the temperature from 37.0 °C on the DNA breaks, whether the temperature-shift caused breaks that could be monitored by the level of PAR. While PAR level did not change significantly when HeLa cells were cultured at 33.5 °C or 37.0 °C, it was significantly increased 2- and 3-fold when cells were cultured for 12 h and 24 h, respectively, at 40.5 °C as compared to 37.0 °C. Similar to the results with HeLa cells, PAR level was increased 2-fold in CHO-K1 cells cultured at 40.5 °C for 24 h as compared to 37.0 °C. As the cellular levels of PAR polymerase1 (PARP1) and PAR glycohydrolase (PARG), a major degradation enzyme for PAR, did not seem to change significantly, this increase could be caused by activation of PARP1 by DNA strand breaks. In fact, γH2AX, claimed to be a marker of DNA double-strand breaks, was found in cell extracts of HeLa cells and CHO-K1 cells at elevated temperature vs. 37.0 °C, and these γH2AX signals were intensified in the presence of 3-aminobenzamide, a PARP inhibitor. The γH2AX immunohistochemistry results in HeLa cells were consistent with Western blot analyses. In HeLa cells, proliferation was significantly suppressed at 40.5 °C in 72 h-continuous cultures and decreased viabilities were also observed after 24–72 h at 40.5 °C. Flow cytometric analyses showed that the HeLa cells were arrested at G2/M after temperature shift-up to 40.5 °C. These physiological changes were potentiated in the presence of 3-aminobenzamide. Decrease in growth rates, increased cytotoxicity and G2/M arrest, were associated with the temperature-shift to 40.5 °C and are indirect evidence of DNA breaks. In addition to γH2AX

  1. Antibody-Directed Phototherapy (ADP

    Directory of Open Access Journals (Sweden)

    M. Adil Butt

    2013-04-01

    Full Text Available Photodynamic therapy (PDT is a clinically-approved but rather under-exploited treatment modality for cancer and pre-cancerous superficial lesions. It utilises a cold laser or LED to activate a photochemical reaction between a light activated drug (photosensitiser-drug and oxygen to generate cytotoxic oxygen species. These free radical species damage cellular components leading to cell death. Despite its benefits, the complexity, limited potency and side effects of PDT have led to poor general usage. However, the research area is very active with an increasing understanding of PDT-related cell biology, photophysics and significant progress in molecular targeting of disease. Monoclonal antibody therapy is maturing and the next wave of antibody therapies includes antibody-drug conjugates (ADCs, which promise to be more potent and curable. These developments could lift antibody-directed phototherapy (ADP to success. ADP promises to increase specificity and potency and improve drug pharmacokinetics, thus delivering better PDT drugs whilst retaining its other benefits. Whole antibody conjugates with first generation ADP-drugs displayed problems with aggregation, poor pharmacokinetics and loss of immuno-reactivity. However, these early ADP-drugs still showed improved selectivity and potency. Improved PS-drug chemistry and a variety of conjugation strategies have led to improved ADP-drugs with retained antibody and PS-drug function. More recently, recombinant antibody fragments have been used to deliver ADP-drugs with superior drug loading, more favourable pharmacokinetics, enhanced potency and target cell selectivity. These improvements offer a promise of better quality PDT drugs.

  2. Neurological and histological consequences induced by in vivo cerebral oxidative stress: evidence for beneficial effects of SRT1720, a sirtuin 1 activator, and sirtuin 1-mediated neuroprotective effects of poly(ADP-ribose) polymerase inhibition.

    Science.gov (United States)

    Gueguen, Cindy; Palmier, Bruno; Plotkine, Michel; Marchand-Leroux, Catherine; Besson, Valérie C

    2014-01-01

    Poly(ADP-ribose)polymerase and sirtuin 1 are both NAD(+)-dependent enzymes. In vitro oxidative stress activates poly(ADP-ribose)polymerase, decreases NAD(+) level, sirtuin 1 activity and finally leads to cell death. Poly(ADP-ribose)polymerase hyperactivation contributes to cell death. In addition, poly(ADP-ribose)polymerase inhibition restores NAD(+) level and sirtuin 1 activity in vitro. In vitro sirtuin 1 induction protects neurons from cell loss induced by oxidative stress. In this context, the role of sirtuin 1 and its involvement in beneficial effects of poly(ADP-ribose)polymerase inhibition were evaluated in vivo in a model of cerebral oxidative stress induced by intrastriatal infusion of malonate in rat. Malonate promoted a NAD(+) decrease that was not prevented by 3-aminobenzamide, a poly(ADP-ribose)polymerase inhibitor, at 4 and 24 hours. However, 3-aminobenzamide increased nuclear SIRT1 activity/expression ratio after oxidative stress. Malonate induced a neurological deficit associated with a striatal lesion. Both were reduced by 3-aminobenzamide and SRT1720, a sirtuin 1 activator, showing beneficial effects of poly(ADP-ribose)polymerase inhibition and sirtuin 1 activation on oxidative stress consequences. EX527, a sirtuin 1 inhibitor, given alone, modified neither the score nor the lesion, suggesting that endogenous sirtuin 1 was not activated during cerebral oxidative stress. However, its association with 3-aminobenzamide suppressed the neurological improvement and the lesion reduction induced by 3-aminobenzamide. The association of 3-aminobenzamide with SRT1720, the sirtuin 1 activator, did not lead to a better protection than 3-aminobenzamide alone. The present data represent the first demonstration that the sirtuin 1 activator SRT1720 is neuroprotective during in vivo cerebral oxidative stress. Furthermore sirtuin 1 activation is involved in the beneficial effects of poly(ADP-ribose)polymerase inhibition after in vivo cerebral oxidative stress.

  3. Neurological and histological consequences induced by in vivo cerebral oxidative stress: evidence for beneficial effects of SRT1720, a sirtuin 1 activator, and sirtuin 1-mediated neuroprotective effects of poly(ADP-ribose polymerase inhibition.

    Directory of Open Access Journals (Sweden)

    Cindy Gueguen

    Full Text Available Poly(ADP-ribosepolymerase and sirtuin 1 are both NAD(+-dependent enzymes. In vitro oxidative stress activates poly(ADP-ribosepolymerase, decreases NAD(+ level, sirtuin 1 activity and finally leads to cell death. Poly(ADP-ribosepolymerase hyperactivation contributes to cell death. In addition, poly(ADP-ribosepolymerase inhibition restores NAD(+ level and sirtuin 1 activity in vitro. In vitro sirtuin 1 induction protects neurons from cell loss induced by oxidative stress. In this context, the role of sirtuin 1 and its involvement in beneficial effects of poly(ADP-ribosepolymerase inhibition were evaluated in vivo in a model of cerebral oxidative stress induced by intrastriatal infusion of malonate in rat. Malonate promoted a NAD(+ decrease that was not prevented by 3-aminobenzamide, a poly(ADP-ribosepolymerase inhibitor, at 4 and 24 hours. However, 3-aminobenzamide increased nuclear SIRT1 activity/expression ratio after oxidative stress. Malonate induced a neurological deficit associated with a striatal lesion. Both were reduced by 3-aminobenzamide and SRT1720, a sirtuin 1 activator, showing beneficial effects of poly(ADP-ribosepolymerase inhibition and sirtuin 1 activation on oxidative stress consequences. EX527, a sirtuin 1 inhibitor, given alone, modified neither the score nor the lesion, suggesting that endogenous sirtuin 1 was not activated during cerebral oxidative stress. However, its association with 3-aminobenzamide suppressed the neurological improvement and the lesion reduction induced by 3-aminobenzamide. The association of 3-aminobenzamide with SRT1720, the sirtuin 1 activator, did not lead to a better protection than 3-aminobenzamide alone. The present data represent the first demonstration that the sirtuin 1 activator SRT1720 is neuroprotective during in vivo cerebral oxidative stress. Furthermore sirtuin 1 activation is involved in the beneficial effects of poly(ADP-ribosepolymerase inhibition after in vivo cerebral oxidative

  4. Improved Triacylglycerol Production in Acinetobacter baylyi ADP1 by Metabolic Engineering

    Directory of Open Access Journals (Sweden)

    Karp Matti

    2011-05-01

    Full Text Available Abstract Background Triacylglycerols are used in various purposes including food applications, cosmetics, oleochemicals and biofuels. Currently the main sources for triacylglycerol are vegetable oils, and microbial triacylglycerol has been suggested as an alternative for these. Due to the low production rates and yields of microbial processes, the role of metabolic engineering has become more significant. As a robust model organism for genetic and metabolic studies, and for the natural capability to produce triacylglycerol, Acinetobacter baylyi ADP1 serves as an excellent organism for modelling the effects of metabolic engineering for energy molecule biosynthesis. Results Beneficial gene deletions regarding triacylglycerol production were screened by computational means exploiting the metabolic model of ADP1. Four deletions, acr1, poxB, dgkA, and a triacylglycerol lipase were chosen to be studied experimentally both separately and concurrently by constructing a knock-out strain (MT with three of the deletions. Improvements in triacylglycerol production were observed: the strain MT produced 5.6 fold more triacylglycerol (mg/g cell dry weight compared to the wild type strain, and the proportion of triacylglycerol in total lipids was increased by 8-fold. Conclusions In silico predictions of beneficial gene deletions were verified experimentally. The chosen single and multiple gene deletions affected beneficially the natural triacylglycerol metabolism of A. baylyi ADP1. This study demonstrates the importance of single gene deletions in triacylglycerol metabolism, and proposes Acinetobacter sp. ADP1 as a model system for bioenergetic studies regarding metabolic engineering.

  5. Control of skeletal muscle mitochondria respiration by adenine nucleotides: differential effect of ADP and ATP according to muscle contractile type in pigs.

    Science.gov (United States)

    Gueguen, N; Lefaucheur, L; Fillaut, M; Vincent, A; Herpin, P

    2005-02-01

    Skeletal muscle exhibits considerable variation in mitochondrial content among fiber types, but it is less clear whether mitochondria from different fiber types also present specific functional and regulatory properties. The present experiment was undertaken on ten 170-day-old pigs to compare functional properties and control of respiration by adenine nucleotides in mitochondria isolated from predominantly slow-twitch (Rhomboideus (RM)) and fast-twitch (Longissimus (LM)) muscles. Mitochondrial ATP synthesis, respiratory control ratio (RCR) and ADP-stimulated respiration with either complex I or II substrates were significantly higher (25-30%, Prespiration. Based on mitochondrial enzyme activities (cytochrome c oxidase [COX], F0F1-ATPase, mitochondrial creatine kinase [mi-CK]), the higher ADP-stimulated respiration rate of RM mitochondria appeared mainly related to a higher maximal oxidative capacity, without any difference in the maximal phosphorylation potential. Mitochondrial K(m) for ADP was similar in RM (4.4+/-0.9 microM) and LM (5.9+/-1.2 microM) muscles (P>0.05) but the inhibitory effect of ATP was more marked in LM (Prespiration by ATP differs according to muscle contractile type and that absolute muscle oxidative capacity not only relies on mitochondrial density but also on mitochondrial functioning per se.

  6. Defense ADP Acquisition Study.

    Science.gov (United States)

    1981-11-30

    generates lengthy acquisition times, but rather, the basis for the delays is related to the Air Force acqusition process. -5- (2) The Current Air...increasing technological merger of these two fields. Fragmentation of organiza- tional responsibility among a variety of rela- tively independent...potential solutions. Early considera- tion of one aspect of technology over another constrains the solution. Recognition of the technological merger of ADP

  7. Effect of Vaccinia virus infection on poly(ADP-ribose)synthesis and DNA metabolism in different cells

    Energy Technology Data Exchange (ETDEWEB)

    Topaloglou, A.; Ott, E.; Altmann, H. (Oesterreichisches Forschungszentrum Seibersdorf G.m.b.H. Inst. fuer Biologie); Zashukhina, G.D.; Sinelschikova, T.A. (AN SSSR, Moscow. Inst. Obshchej Genetiki)

    1983-07-14

    In Chang liver cells and rat spleen cells infected with Vaccinia virus, DNA synthesis, repair replication after UV irradiation and poly(ADP-ribose)(PAR) synthesis were determined. In the time post infection semiconservative DNA synthesis showed only a slight reduction. DNA repair replication was not very different from controls 4 hours p.i. but was enhanced 24 hours after infection compared to noninfected cells. PAR synthesis was also not changed very much 4 hours p.i. but was decreased significantly after 24 hours. The determination of radioactivity resulting from /sup 3/H-NAD, showed a marked reduction of PAR in the spacer region of chromatin 24 hours p.i., but in addition, PAR located in the core region, was reduced, too.

  8. Recovery of human lymphocytes damaged with. gamma. -radiation or enzymatically produced oxygen radicals: different effects of poly(ADP-ribosyl)polymerase inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Marini, M.; Zunica, G. (Ist. di Istologia ed Embriologia Generale, Bologna (Italy)); Tamba, M. (Consiglio Nazionale delle Ricerche, Bologna (Italy). Lab. di Fotochimica e Radiazioni d' Alta Energia); Cossarizza, A.; Monti, D.; Franceschi, C. (Ist. di Patologia Generale, Modena (Italy))

    1990-08-01

    Quiescent human lymphocytes were damaged in two different ways, both producing toxic oxygen radicals: xanthine oxidase plus hypoxanthine (XOD/HYP), or {gamma}-rays. Under conditions where DNA synthesis was reduced to 10-20% of control, inhibitors of poly(ADP-ribosyl)polymerase (ADPRP, an enzyme that becomes activated in the presence of DNA strand breaks) allowed lymphocytes to recover completely when the damage was caused by XOD/HYP, but they did not affect DNA synthesis of irradiated cells. However, a protective effect of ADPRP inhibitors was observed with irradiated lymphocytes receiving doses {ge}50Gy. Unscheduled DNA synthesis was significantly increased when lymphocytes were damaged by high radiation doses in the presence of ADPRP inhibitors. (author).

  9. Strain rate effects in stress corrosion cracking

    Energy Technology Data Exchange (ETDEWEB)

    Parkins, R.N. (Newcastle upon Tyne Univ. (UK). Dept. of Metallurgy and Engineering Materials)

    1990-03-01

    Slow strain rate testing (SSRT) was initially developed as a rapid, ad hoc laboratory method for assessing the propensity for metals an environments to promote stress corrosion cracking. It is now clear, however, that there are good theoretical reasons why strain rate, as opposed to stress per se, will often be the controlling parameter in determining whether or not cracks are nucleated and, if so, are propagated. The synergistic effects of the time dependence of corrosion-related reactions and microplastic strain provide the basis for mechanistic understanding of stress corrosion cracking in high-pressure pipelines and other structures. However, while this may be readily comprehended in the context of laboratory slow strain tests, its extension to service situations may be less apparent. Laboratory work involving realistic stressing conditions, including low-frequency cyclic loading, shows that strain or creep rates give good correlation with thresholds for cracking and with crack growth kinetics.

  10. Flexoelectricity: strain gradient effects in ferroelectrics

    Energy Technology Data Exchange (ETDEWEB)

    Ma Wenhui [Department of Physics, Shantou Unversity, Shantou, Guangdong 515063 (China)

    2007-12-15

    Mechanical strain gradient induced polarization effect or flexoelectricity in perovskite-type ferroelectric and relaxor ferroelectric ceramics was investigated. The flexoelectric coefficients measured at room temperature ranged from about 1 {mu} C m{sup -1} for lead zirconate titanate to 100 {mu} C m{sup -1} for barium strontium titanate. Flexoelectric effects were discovered to be sensitive to chemical makeup, phase symmetry, and domain structures. Based on phenomenological discussion and experimental data on flexoelectricity, the present study proposed that mechanical strain gradient field could influence polarization responses in a way analogous to electric field. Flexoelectric coefficients were found to be nonlinearly enhanced by dielectric permittivity and strain gradient. Interfacial mismatch in epitaxial thin films can give rise to high strain gradients, enabling flexoelectric effects to make a significant impact in properly engineered ferroelectric heterostructure systems.

  11. Flexoelectricity: strain gradient effects in ferroelectrics

    International Nuclear Information System (INIS)

    Ma Wenhui

    2007-01-01

    Mechanical strain gradient induced polarization effect or flexoelectricity in perovskite-type ferroelectric and relaxor ferroelectric ceramics was investigated. The flexoelectric coefficients measured at room temperature ranged from about 1 μ C m -1 for lead zirconate titanate to 100 μ C m -1 for barium strontium titanate. Flexoelectric effects were discovered to be sensitive to chemical makeup, phase symmetry, and domain structures. Based on phenomenological discussion and experimental data on flexoelectricity, the present study proposed that mechanical strain gradient field could influence polarization responses in a way analogous to electric field. Flexoelectric coefficients were found to be nonlinearly enhanced by dielectric permittivity and strain gradient. Interfacial mismatch in epitaxial thin films can give rise to high strain gradients, enabling flexoelectric effects to make a significant impact in properly engineered ferroelectric heterostructure systems

  12. Effective stress coefficient for uniaxial strain condition

    DEFF Research Database (Denmark)

    Alam, M.M.; Fabricius, I.L.

    2012-01-01

    one dimensional rock mechanical deformation. We further investigated the effect of boundary condition on the stress dependency of effective stress coefficient and discussed its application in reservoir study. As stress field in the reservoirs are most unlikely to be hydrostatic, effective stress...... determined under uniaxial strain condition will be more relevant in reservoir studies. Copyright 2012 ARMA, American Rock Mechanics Association....

  13. Poly-ADP-ribosylation of proteins responds to cellular perturbations

    International Nuclear Information System (INIS)

    Schneeweiss, F.H.A.; Sharan, R.N.

    1999-01-01

    From the results presented above it is quite obvious that poly-ADP-ribosylation reaction is a sensitive parameter to monitor cellular responses to a wide variety of perturbations. Having developed a monolayer assay system using 32 P-NAD + as a marker, it has become possible to measure levels of cellular ADP-ribosylation more precisely. It has been demonstrated that the trigger of poly-ADP-ribosylation reaction may involve different cellular components for different perturbations. In this, membrane has been found to be important. The study has been particularly informative in the realm of DNA damage and repair following qualitatively different radiation assaults. As poly-ADP-ribosylation in eukaryotic cells primarily affects chromosomal proteins, notably histones, the reaction is strongly triggered in response to single and double strand breaks in DNA. Therefore, level of cellular poly-ADP-ribosylation can potentially be used as a biosensor of radiation induced strand breaks and can be specially useful in clinical monitoring of progress of radiotherapy. The assay of poly-ADP-ribosylation, however, requires use of radiolabelled tracer, e.g. 32 P-NAD + . Due to this, study of poly-ADP-ribosylation can not be extended to monitor effects of incorporated radionuclides. In order to overcome this shortcoming and to make the assay more sensitive and quick, a Western blot immunoassay has been developed. The preliminary indications are that the immunoassay of poly-ADP-ribosylation will fulfil the requirements to use poly-ADP-ribosylation as a sensitive, convenient and clinically applicable biosensor of cell response not only to radiations but also to different perturbations. (orig.)

  14. Giant flexoelectric effect through interfacial strain relaxation.

    Science.gov (United States)

    Lee, Daesu; Noh, Tae Won

    2012-10-28

    Interfacial strain gradients in oxide epitaxial thin films provide an interesting opportunity to study flexoelectric effects and their potential applications. Oxide epitaxial thin films can exhibit giant and tunable flexoelectric effects, which are six or seven orders of magnitude larger than those in conventional bulk solids. The strain gradient in an oxide epitaxial thin film can generate an electric field above 1 MV m(-1) by flexoelectricity, large enough to affect the physical properties of the film. Giant flexoelectric effects on ferroelectric properties are discussed in this overview of recent experimental observations.

  15. Symposium cellular response to DNA damage the role of poly(ADP-ribose) poly(ADP-ribose) in the cellular response to DNA damage

    International Nuclear Information System (INIS)

    Berger, N.A.

    1985-01-01

    Poly(ADP-ribose) polymerase is a chromatin-bound enzyme which, on activation by DNA strand breaks, catalyzes the successive transfer of ADP-ribose units from NAD to nuclear proteins. Poly(ADP-ribose) synthesis is stimulated by DNA strand breaks, and the polymer may alter the structure and/or function of chromosomal proteins to facilitate the DNA repair process. Inhibitors of Poly(ADP-ribose) polymerase or deficiencies of the substrate, NAD, lead to retardation of the DNA repair process. When DNA strand breaks are extensive or when breaks fail to be repaired, the stimulus for activation of Poly(ADP-ribose) persists and the activated enzyme is capable of totaly consuming cellular pools of NAD. Depletion of NAD and consequent lowering of cellular ATP pools, due to activation of Poly(ADP-ribose) polymerase, may account for rapid cell death before DNA repair takes place and before the genetic effects of DNA damage become manifest

  16. Piezoelectric effect in strained quantum wells

    International Nuclear Information System (INIS)

    Dang, L.S.; Andre, R.; Cibert, J.

    1995-01-01

    This paper describes some physical aspects of the piezoelectric effect which takes place in strained semiconductor heterostructures grown along a polar axis. First we show how piezoelectric fields can be accurately measured by optical spectroscopy. Then we discuss about the origin of the non-linear piezoelectric effect reported recently for CdTe, and maybe for InAs as well. Finally we compare excitonic effects in piezoelectric and non-piezoelectric quantum wells. (orig.)

  17. Effect of strain rate and temperature at high strains on fatigue behavior of SAP alloys

    DEFF Research Database (Denmark)

    Blucher, J.T.; Knudsen, Per; Grant, N.J.

    1968-01-01

    Fatigue behavior of three SAP alloys of two nominal compositions (7 and 13% Al2O3) was studied in terms of strain rate and temperature at high strains; strain rate had no effect on life at 80 F, but had increasingly greater effect with increasing temperature above 500 F; life decreased with decre......Fatigue behavior of three SAP alloys of two nominal compositions (7 and 13% Al2O3) was studied in terms of strain rate and temperature at high strains; strain rate had no effect on life at 80 F, but had increasingly greater effect with increasing temperature above 500 F; life decreased...

  18. Strain rate effects for spallation of concrete

    Directory of Open Access Journals (Sweden)

    Häussler-Combe Ulrich

    2015-01-01

    Full Text Available Appropriate triaxial constitutive laws are the key for a realistic simulation of high speed dynamics of concrete. The strain rate effect is still an open issue within this context. In particular the question whether it is a material property – which can be covered by rate dependent stress strain relations – or mainly an effect of inertia is still under discussion. Experimental and theoretical investigations of spallation of concrete specimen in a Hopkinson Bar setup may bring some evidence into this question. For this purpose the paper describes the VERD model, a newly developed constitutive law for concrete based on a damage approach with included strain rate effects [1]. In contrast to other approaches the dynamic strength increase is not directly coupled to strain rate values but related to physical mechanisms like the retarded movement of water in capillary systems and delayed microcracking. The constitutive law is fully triaxial and implemented into explicit finite element codes for the investigation of a wide range of concrete structures exposed to impact and explosions. The current setup models spallation experiments with concrete specimen [2]. The results of such experiments are mainly related to the dynamic tensile strength and the crack energy of concrete which may be derived from, e.g., the velocity of spalled concrete fragments. The experimental results are compared to the VERD model and two further constitutive laws implemented in LS-Dyna. The results indicate that both viscosity and retarded damage are required for a realistic description of the material behaviour of concrete exposed to high strain effects [3].

  19. Effective stress coefficient for uniaxial strain condition

    DEFF Research Database (Denmark)

    Alam, M.M.; Fabricius, I.L.

    2012-01-01

    The effective stress coefficient, introduced by Biot, is used for predicting effective stress or pore pressure in the subsurface. It is not a constant value. It is different for different types of sediment and it is stress dependent. We used a model, based on contact between the grains to describ...... determined under uniaxial strain condition will be more relevant in reservoir studies. Copyright 2012 ARMA, American Rock Mechanics Association....

  20. The angiotensin-converting enzyme inhibitor captopril inhibits poly(ADP-ribose)polymerase activation and exerts beneficial effects in an ovine model of burn and smoke injury

    Science.gov (United States)

    Asmussen, Sven; Bartha, Eva; Olah, Gabor; Sbrana, Elena; Rehberg, Sebastian W.; Yamamoto, Yusuke; Enkhbaatar, Perenlei; Hawkins, Hal K.; Ito, Hiroshi; Cox, Robert A.; Traber, Lillian D.; Traber, Daniel L.; Szabo, Csaba

    2011-01-01

    We investigated the effect of the angiotensin converting enzyme (ACE) inhibitor captopril in a clinically relevant ovine model of smoke and burn injury, with special reference to oxidative stress, activation of poly(ADP-ribose) polymerase in the lung and in circulating leukocytes. Female, adult sheep (28–40 kg) were divided into 3 groups. After tracheostomy and under deep anesthesia both vehicle-control (n=5) and captopril (20 mg/kg/d, iv., starting 0.5 hour before the injury) treated (n=5) groups were subjected to 2×20%, third degree burn injury and were insufflated with 48 breaths of cotton smoke. A sham group not receiving burn/smoke was also studied (n=5). Animals were mechanically ventilated and fluid resuscitated for 24 h in the awake state. Burn and smoke injury resulted in an upregulation of ACE in the lung, evidenced by immunohistochemical determination and Western blotting. Burn and smoke injury resulted in pulmonary dysfunction, as well as systemic hemodynamic alterations. Captopril treatment of burn and smoke animals improved PaO2/FiO2 ratio and pulmonary shunt fraction and reduced the degree of lung edema. There was a marked increase in PAR levels in circulating leukocytes after burn/smoke injury, which was significantly decreased by captopril. The pulmonary level of ACE and the elevated pulmonary levels of TGF-β in response to burn and smoke injury were significantly decreased by captopril treatment. Our results suggest that the ACE inhibitor captopril exerts beneficial effects on the pulmonary function in burn/smoke injury. The effects of the ACE inhibitor may be related to the prevention of ROS-induced PARP over-activation. ACE inhibition may also exert additional beneficial effects by inhibiting the expression of the pro-fibrotic mediator TGF-β. PMID:21701415

  1. Cross talk between poly(ADP-ribose) polymerase 1 methylation and oxidative stress involved in the toxic effect of anatase titanium dioxide nanoparticles.

    Science.gov (United States)

    Bai, Wenlin; Chen, Yujiao; Gao, Ai

    2015-01-01

    Given the tremendous growth in the application of titanium dioxide nanoparticles (TNPs), concerns about the potential health hazards of TNPs to humans have been raised. Poly(ADP-ribose) polymerase 1 (PARP-1), a highly conserved DNA-binding protein, is involved in many molecular and cellular processes. Limited data demonstrated that certain nanomaterials induced the aberrant hypermethylation of PARP-1. However, the mechanism involved in TNP-induced PARP-1 abnormal methylation has not been studied. A549 cells were incubated with anatase TNPs (22.1 nm) for 24 hours pretreatment with or without methyltransferase inhibitor 5-aza-2'-deoxycytidine and the reactive oxygen species (ROS) scavenger α-lipoic acid to assess the possible role of methylation and ROS in the toxic effect of TNPs. After TNPs characterization, a battery of assays was performed to evaluate the toxic effect of TNPs, PARP-1 methylation status, and oxidative damage. Results showed that TNPs decreased the cell viability in a dose-dependent manner, in accordance with the increase of lactate dehydrogenase activity, which indicated membrane damage of cells. Similar to the high level of PARP-1 methylation, the generation of ROS was significantly increased after exposure to TNPs for 24 hours. Furthermore, α-lipoic acid decreased TNP-induced ROS generation and then attenuated TNP-triggered PARP-1 hypermethylation. Meanwhile, 5-aza-2'-deoxycytidine simultaneously decreased the ROS generation induced by TNPs, resulting in the decline of PARP-1 methylation. In summary, TNPs triggered the aberrant hypermethylation of the PARP-1 promoter and there was a cross talk between oxidative stress and PARP-1 methylation in the toxic effect of TNPs.

  2. Cross talk between poly(ADP-ribose) polymerase 1 methylation and oxidative stress involved in the toxic effect of anatase titanium dioxide nanoparticles

    Science.gov (United States)

    Bai, Wenlin; Chen, Yujiao; Gao, Ai

    2015-01-01

    Given the tremendous growth in the application of titanium dioxide nanoparticles (TNPs), concerns about the potential health hazards of TNPs to humans have been raised. Poly(ADP-ribose) polymerase 1 (PARP-1), a highly conserved DNA-binding protein, is involved in many molecular and cellular processes. Limited data demonstrated that certain nanomaterials induced the aberrant hypermethylation of PARP-1. However, the mechanism involved in TNP-induced PARP-1 abnormal methylation has not been studied. A549 cells were incubated with anatase TNPs (22.1 nm) for 24 hours pretreatment with or without methyltransferase inhibitor 5-aza-2′-deoxycytidine and the reactive oxygen species (ROS) scavenger α-lipoic acid to assess the possible role of methylation and ROS in the toxic effect of TNPs. After TNPs characterization, a battery of assays was performed to evaluate the toxic effect of TNPs, PARP-1 methylation status, and oxidative damage. Results showed that TNPs decreased the cell viability in a dose-dependent manner, in accordance with the increase of lactate dehydrogenase activity, which indicated membrane damage of cells. Similar to the high level of PARP-1 methylation, the generation of ROS was significantly increased after exposure to TNPs for 24 hours. Furthermore, α-lipoic acid decreased TNP-induced ROS generation and then attenuated TNP-triggered PARP-1 hypermethylation. Meanwhile, 5-aza-2′-deoxycytidine simultaneously decreased the ROS generation induced by TNPs, resulting in the decline of PARP-1 methylation. In summary, TNPs triggered the aberrant hypermethylation of the PARP-1 promoter and there was a cross talk between oxidative stress and PARP-1 methylation in the toxic effect of TNPs. PMID:26366077

  3. The Dichotomy of the Poly(ADP-Ribose Polymerase-Like Thermozyme from Sulfolobus solfataricus

    Directory of Open Access Journals (Sweden)

    Maria Rosaria Faraone Mennella

    2018-01-01

    Full Text Available The first evidence of an ADP-ribosylating activity in Archaea was obtained in Sulfolobus solfataricus(strain MT-4 where a poly(ADP-ribose polymerase (PARP-like thermoprotein, defined with the acronymous PARPSso, was found. Similarly to the eukaryotic counterparts PARPSso cleaves beta-nicotinamide adenine dinucleotide to synthesize oligomers of ADP-ribose; cross-reacts with polyclonal anti-PARP-1 catalytic site antibodies; binds DNA. The main differences rely on the molecular mass (46.5 kDa and the thermophily of PARPSso which works at 80 °C. Despite the biochemical properties that allow correlating it to PARP enzymes, the N-terminal and partial amino acid sequences available suggest that PARPSso belongs to a different group of enzymes, the DING proteins, an item discussed in detail in this review.This finding makes PARPSso the first example of a DING protein in Archaea and extends the existence of DING proteins into all the biological kingdoms. PARPSsohas a cell peripheral localization, along with the edge of the cell membrane. The ADP-ribosylation reaction is reverted by a poly(ADP-ribose glycohydrolase-like activity, able to use the eukaryotic poly(ADP-ribose as a substrate too. Here we overview the research of (ADP-ribosylation in Sulfolobus solfataricus in the past thirty years and discuss the features of PARPSso common with the canonical poly(ADP-ribose polymerases, and the structure fitting with that of DING proteins.

  4. Strain gradient effects on cyclic plasticity

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Legarth, Brian Nyvang

    2010-01-01

    Size effects on the cyclic shear response are studied numerically using a recent higher order strain gradient visco-plasticity theory accounting for both dissipative and energetic gradient hardening. Numerical investigations of the response under cyclic pure shear and shear of a finite slab between...... rigid platens have been carried out, using the finite element method. It is shown for elastic–perfectly plastic solids how dissipative gradient effects lead to increased yield strength, whereas energetic gradient contributions lead to increased hardening as well as a Bauschinger effect. For linearly...... hardening materials it is quantified how dissipative and energetic gradient effects promote hardening above that of conventional predictions. Usually, increased hardening is attributed to energetic gradient effects, but here it is found that also dissipative gradient effects lead to additional hardening...

  5. Effects of poly (ADP-ribose) polymerase-1 (PARP-1) inhibition on sulfur mustard-induced cutaneous injuries in vitro and in vivo.

    Science.gov (United States)

    Liu, Feng; Jiang, Ning; Xiao, Zhi-Yong; Cheng, Jun-Ping; Mei, Yi-Zhou; Zheng, Pan; Wang, Li; Zhang, Xiao-Rui; Zhou, Xin-Bo; Zhou, Wen-Xia; Zhang, Yong-Xiang

    2016-01-01

    Early studies with first-generation poly (ADP-ribose) polymerase (PARP) inhibitors have already indicated some therapeutic potential for sulfur mustard (SM) injuries. The available novel and more potential PARP inhibitors, which are undergoing clinical trials as drugs for cancer treatment, bring it back to the centre of interest. However, the role of PARP-1 in SM-induced injury is not fully understood. In this study, we selected a high potent specific PARP inhibitor ABT-888 as an example to investigate the effect of PARP inhibitor in SM injury. The results showed that in both the mouse ear vesicant model (MEVM) and HaCaT cell model, PARP inhibitor ABT-888 can reduce cell damage induced by severe SM injury. ABT-888 significantly reduced SM induced edema and epidermal necrosis in MEVM. In the HaCaT cell model, ABT-888 can reduce SM-induced NAD(+)/ATP depletion and apoptosis/necrosis. Then, we studied the mechanism of PARP-1 in SM injury by knockdown of PARP-1 in HaCaT cells. Knockdown of PARP-1 protected cell viability and downregulated the apoptosis checkpoints, including p-JNK, p-p53, Caspase 9, Caspase 8, c-PARP and Caspase 3 following SM-induced injury. Furthermore, the activation of AKT can inhibit autophagy via the regulation of mTOR. Our results showed that SM exposure could significantly inhibit the activation of Akt/mTOR pathway. Knockdown of PARP-1 reversed the SM-induced suppression of the Akt/mTOR pathway. In summary, the results of our study indicated that the protective effects of downregulation of PARP-1 in SM injury may be due to the regulation of apoptosis, necrosis, energy crisis and autophagy. However, it should be noticed that PARP inhibitor ABT-888 further enhanced the phosphorylation of H2AX (S139) after SM exposure, which indicated that we should be very careful in the application of PARP inhibitors in SM injury treatment because of the enhancement of DNA damage.

  6. Effects of poly (ADP-ribose polymerase-1 (PARP-1 inhibition on sulfur mustard-induced cutaneous injuries in vitro and in vivo

    Directory of Open Access Journals (Sweden)

    Feng Liu

    2016-04-01

    Full Text Available Early studies with first-generation poly (ADP-ribose polymerase (PARP inhibitors have already indicated some therapeutic potential for sulfur mustard (SM injuries. The available novel and more potential PARP inhibitors, which are undergoing clinical trials as drugs for cancer treatment, bring it back to the centre of interest. However, the role of PARP-1 in SM-induced injury is not fully understood. In this study, we selected a high potent specific PARP inhibitor ABT-888 as an example to investigate the effect of PARP inhibitor in SM injury. The results showed that in both the mouse ear vesicant model (MEVM and HaCaT cell model, PARP inhibitor ABT-888 can reduce cell damage induced by severe SM injury. ABT-888 significantly reduced SM induced edema and epidermal necrosis in MEVM. In the HaCaT cell model, ABT-888 can reduce SM-induced NAD+/ATP depletion and apoptosis/necrosis. Then, we studied the mechanism of PARP-1 in SM injury by knockdown of PARP-1 in HaCaT cells. Knockdown of PARP-1 protected cell viability and downregulated the apoptosis checkpoints, including p-JNK, p-p53, Caspase 9, Caspase 8, c-PARP and Caspase 3 following SM-induced injury. Furthermore, the activation of AKT can inhibit autophagy via the regulation of mTOR. Our results showed that SM exposure could significantly inhibit the activation of Akt/mTOR pathway. Knockdown of PARP-1 reversed the SM-induced suppression of the Akt/mTOR pathway. In summary, the results of our study indicated that the protective effects of downregulation of PARP-1 in SM injury may be due to the regulation of apoptosis, necrosis, energy crisis and autophagy. However, it should be noticed that PARP inhibitor ABT-888 further enhanced the phosphorylation of H2AX (S139 after SM exposure, which indicated that we should be very careful in the application of PARP inhibitors in SM injury treatment because of the enhancement of DNA damage.

  7. Effects of the Strain Rate Sensitivity and Strain Hardening on the Saturated Impulse of Plates

    Directory of Open Access Journals (Sweden)

    Ling Zhu

    Full Text Available Abstract This paper studies the stiffening effects of the material strain rate sensitivity and strain hardening on the saturated impulse of elastic, perfectly plastic plates. Finite element (FE code ABAQUS is employed to simulate the elastoplastic response of square plates under rectangular pressure pulse. Rigid-plastic analyses for saturated impulse, which consider strain rate sensitivity and strain hardening, are conducted. Satisfactory agreement between the finite element models (FEM and predictions of the rigid-plastic analysis is obtained, which verifies that the proposed rigid-plastic methods are effective to solve the problem including strain rate sensitivity and strain hardening. The quantitative results for the scale effect of the strain rate sensitivity are given. The results for the stiffening effects suggest that two general stiffening factors n 1 and n 2, which characterizes the strain rate sensitivity and strain hardening effect, respectively can be defined. The saturated displacement is inversely proportional to the stiffening factors (i.e. n 1 and n 2 and saturated impulse is inversely proportional to the square roots of the stiffening factors (i.e. n 1 and n 2. Formulae for displacement and saturated impulse are proposed based on the empirical analysis.

  8. THE EFFECT OF DIFFERENT PROBIOTIC STRAINS ON FATTENINTHE EFFECT OF DIFFERENT PROBIOTIC STRAINS ON F

    Directory of Open Access Journals (Sweden)

    Cyril Hrnčár

    2013-02-01

    Full Text Available The aim of this work was to verify the effect of different probiotic strains applied through a drinking water source to fattening and carcass parameters of broiler ducks. Fattening experiment was realised in half-operating conditions of experimental basis of Department of Poultry Science and Small Animal Husbandry in three-floor cage technology. Totally 90 broiler duck were divided to three groups. Experimental group 1 (n=30 received probiotic strain Lactobacillus fermentum CCM 7158 with concentration of 1x109 colony forming units (CFU in drinking water daily addition of 0.90 g day 1 to day 56 of fattening. Experimental group 2 (n=30 received probiotic strain Enterococcus faecium M 74 with concentration of 1x109 colony forming units (CFU in drinking water daily addition of 0.45 g day 1 to day 56 of fattening. The control group of birds (n=30 received water without any probiotics. The supplementation of probiotic strains Lactobacillus fermentum and Enterococcus faecium no significant affected (P≥0.05 final body weight, feed consumption and mortality of broiler ducks. From carcass parameters, we recorded statistically significant (P<0.05 reduction in weight of abdominal fat of broiler ducks for application of tested probiotic strains.

  9. Active strain modulation in field effect devices

    NARCIS (Netherlands)

    van Hemert, T.; Hueting, Raymond Josephus Engelbart

    2012-01-01

    In this work we propose a novel feature for the transistor: a piezo-electric layer for strain modulation of the channel. The strain is formed at strong inversion only, to obtain a lower threshold voltage, but will be absent in the off-state to preserve the unstrained leakage current. Our results,

  10. Mutations of human DNA topoisomerase I at poly(ADP-ribose) binding sites: modulation of camptothecin activity by ADP-ribose polymers.

    Science.gov (United States)

    Tesauro, Cinzia; Graziani, Grazia; Arnò, Barbara; Zuccaro, Laura; Muzi, Alessia; D'Annessa, Ilda; Santori, Elettra; Tentori, Lucio; Leonetti, Carlo; Fiorani, Paola; Desideri, Alessandro

    2014-09-17

    DNA topoisomerases are key enzymes that modulate the topological state of DNA through the breaking and rejoining of DNA strands. Human topoisomerase I belongs to the family of poly(ADP-ribose)-binding proteins and is the target of camptothecin derived anticancer drugs. Poly(ADP-ribosyl)ation occurs at specific sites of the enzyme inhibiting the cleavage and enhancing the religation steps during the catalytic cycle. Thus, ADP-ribose polymers antagonize the activity of topoisomerase I poisons, whereas PARP inhibitors increase their antitumor effects. Using site-directed mutagenesis we have analyzed the interaction of human topoisomerase I and poly(ADP-ribose) through enzymatic activity and binding procedures. Mutations of the human topoisomerase I hydrophobic or charged residues, located on the putative polymer binding sites, are not sufficient to abolish or reduce the binding of the poly(ADP-ribose) to the protein. These results suggest either the presence of additional binding sites or that the mutations are not enough perturbative to destroy the poly(ADP-ribose) interaction, although in one mutant they fully abolish the enzyme activity. It can be concluded that mutations at the hydrophobic or charged residues of the putative polymer binding sites do not interfere with the ability of poly(ADP-ribose) to antagonize the antitumor activity of topoisomerase I poisons.

  11. Structures of the human poly (ADP-ribose glycohydrolase catalytic domain confirm catalytic mechanism and explain inhibition by ADP-HPD derivatives.

    Directory of Open Access Journals (Sweden)

    Julie A Tucker

    Full Text Available Poly(ADP-ribose glycohydrolase (PARG is the only enzyme known to catalyse hydrolysis of the O-glycosidic linkages of ADP-ribose polymers, thereby reversing the effects of poly(ADP-ribose polymerases. PARG deficiency leads to cell death whilst PARG depletion causes sensitisation to certain DNA damaging agents, implicating PARG as a potential therapeutic target in several disease areas. Efforts to develop small molecule inhibitors of PARG activity have until recently been hampered by a lack of structural information on PARG. We have used a combination of bio-informatic and experimental approaches to engineer a crystallisable, catalytically active fragment of human PARG (hPARG. Here, we present high-resolution structures of the catalytic domain of hPARG in unliganded form and in complex with three inhibitors: ADP-ribose (ADPR, adenosine 5'-diphosphate (hydroxymethylpyrrolidinediol (ADP-HPD and 8-n-octyl-amino-ADP-HPD. Our structures confirm conservation of overall fold amongst mammalian PARG glycohydrolase domains, whilst revealing additional flexible regions in the catalytic site. These new structures rationalise a body of published mutational data and the reported structure-activity relationship for ADP-HPD based PARG inhibitors. In addition, we have developed and used biochemical, isothermal titration calorimetry and surface plasmon resonance assays to characterise the binding of inhibitors to our PARG protein, thus providing a starting point for the design of new inhibitors.

  12. 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

  13. Valley Hall effect and Nernst effect in strain engineered graphene

    Science.gov (United States)

    Niu, Zhi Ping; Yao, Jian-ming

    2018-04-01

    We theoretically predict the existence of tunneling valley Hall effect and Nernst effect in the normal/strain/normal graphene junctions, where a strained graphene is sandwiched by two normal graphene electrodes. By applying an electric bias a pure transverse valley Hall current with longitudinal charge current is generated. If the system is driven by a temperature bias, a valley Nernst effect is observed, where a pure transverse valley current without charge current propagates. Furthermore, the transverse valley current can be modulated by the Fermi energy and crystallographic orientation. When the magnetic field is further considered, we obtain a fully valley-polarized current. It is expected these features may be helpful in the design of the controllable valleytronic devices.

  14. Inhibition of gamma-ray dose-rate effects by D/sup 2/O and inhibitors of poly(ADP-ribose) synthetase in cultured mammalian L5178Y cells

    Energy Technology Data Exchange (ETDEWEB)

    Ueno, A.M.; Tanaka, O.; Matsudaira, H.

    1984-06-01

    Effects of deuterium oxide (D/sub 2/O) and 3-aminobenzamide, an inhibitor of poly(ADP-ribose) synthetase, on cell proliferation and survival were studied in cultured mammalian L5178Y cells under growing conditions and after acute and low-dose-rate irradiation at about 0.1 to 0.4 Gy/hr of ..gamma.. rays. Growth of irradiated and unirradiated cells was inhibited by 45% D/sub 2/O but not by 3-aminobenzamide at 10mM, except for treatments longer than 30 hr. The presence of these agents either alone or in combination during irradiation at low dose rates suppressed almost totally the decrease in cell killing due to the decrease in dose rate. Among other inhibitors tested, theobromine and theophylline were found to be effective in eliminating the dose-rate effects of ..gamma.. rays. Possible mechanisms underlying the inhibition are discussed.

  15. Phosphate and ADP Differently Inhibit Coordinated Smooth Muscle Myosin Groups

    Science.gov (United States)

    Hilbert, Lennart; Balassy, Zsombor; Zitouni, Nedjma B.; Mackey, Michael C.; Lauzon, Anne-Marie

    2015-01-01

    Actin filaments propelled in vitro by groups of skeletal muscle myosin motors exhibit distinct phases of active sliding or arrest, whose occurrence depends on actin length (L) within a range of up to 1.0 μm. Smooth muscle myosin filaments are exponentially distributed with ≈150 nm average length in vivo—suggesting relevance of the L-dependence of myosin group kinetics. Here, we found L-dependent actin arrest and sliding in in vitro motility assays of smooth muscle myosin. We perturbed individual myosin kinetics with varying, physiological concentrations of phosphate (Pi, release associated with main power stroke) and adenosine diphosphate (ADP, release associated with minor mechanical step). Adenosine triphosphate was kept constant at physiological concentration. Increasing [Pi] lowered the fraction of time for which actin was actively sliding, reflected in reduced average sliding velocity (ν) and motile fraction (fmot, fraction of time that filaments are moving); increasing [ADP] increased the fraction of time actively sliding and reduced the velocity while sliding, reflected in reduced ν and increased fmot. We introduced specific Pi and ADP effects on individual myosin kinetics into our recently developed mathematical model of actin propulsion by myosin groups. Simulations matched our experimental observations and described the inhibition of myosin group kinetics. At low [Pi] and [ADP], actin arrest and sliding were reflected by two distinct chemical states of the myosin group. Upon [Pi] increase, the probability of the active state decreased; upon [ADP] increase, the probability of the active state increased, but the active state became increasingly similar to the arrested state. PMID:25650929

  16. Size-effects in plane strain sheet-necking

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Redanz, Pia

    2004-01-01

    A finite strain generalization of the strain gradient plasticity theory by Fleck and Hutchinson (J. Mech. Phys. Solids 49 (2001a) 2245) is proposed and used to study size effects in plane strain necking of thin sheets using the finite element method. Both sheets with rigid grips at the ends...... and specimens with shear free ends are analyzed. The strain gradient plasticity theory predicts delayed onset of localization when compared to conventional theory, and it depresses deformation localization in the neck. The sensitivity to imperfections is analyzed as well as differently hardening materials. (C...

  17. Size-effects in plane strain sheet-necking

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof; Redanz, Pia

    2003-01-01

    A finite strain generalization of the strain gradient plasticity theory by Fleck and Hutchinson (2001) is proposed and used to study size effects in plane strain necking of thin sheets using the finite element method. Both sheets with rigid grips at the ends and specimens with shear free ends...... are analyzed. The strain gradient plasticity theory predicts delayed onset of localization when compared to conventional theory, and it depresses deformation localization in the neck. The sensitivity to imperfections is analyzed as well as differently hardening materials....

  18. 26 CFR 1.401(k)-2 - ADP test.

    Science.gov (United States)

    2010-04-01

    ... 26 Internal Revenue 5 2010-04-01 2010-04-01 false ADP test. 1.401(k)-2 Section 1.401(k)-2 Internal... TAXES Pension, Profit-Sharing, Stock Bonus Plans, Etc. § 1.401(k)-2 ADP test. (a) Actual deferral percentage (ADP) test—(1) In general—(i) ADP test formula. A cash or deferred arrangement satisfies the ADP...

  19. Oral administration of polyphenolic compounds from cognac decreases ADP-induced platelet aggregation and reduces chronotropic effect of isoprenaline in rats.

    Science.gov (United States)

    Carusio, N; Wangensteen, R; Filippelli, A; Andriantsitohaina, R

    2008-01-01

    This study sought to evaluate whether consumption of polyphenol extract from Cognac (CPC) modulates platelet activation and cardiovascular reactivity in rats. Male Wistar rats were treated daily for 4 weeks by intra-gastric gavage receiving CPC at 80 mg/kg/day or vehicle (5 % glucose). Platelet adhesion and aggregation in response to different activators were assessed. Cardiac and vascular reactivity in response to various agonists as well as NO measurement by electron paramagnetic resonance technique were investigated in isolated heart and thoracic aorta. Oral administration of CPC decreased platelet aggregation induced by ADP but not by collagen. CPC did not affect adhesion to collagen. The chronotropic but not the inotropic response to isoprenaline was reduced without alteration of NO production in hearts from CPC-treated rats. CPC treatment did not affect ex vivo relaxation to acetylcholine nor NO content of rat aorta. CPC did not significantly alter the response to phenylephrine in aorta despite the participation of endothelial vasoconstrictor products. In summary, chronic treatment with CPC has no impact on ex vivo vascular and cardiac reactivity; however, it reduced heart work and platelet aggregation. These data suggest the existence of compounds in Cognac that may decrease the risk of coronary thrombosis and protect against some cardiac diseases.

  20. Strain Rate Effects in CFRP Used For Blast Mitigation

    Directory of Open Access Journals (Sweden)

    Sarah. L. Orton

    2014-04-01

    Full Text Available The purpose of this research is to gain a better understanding of strain rate effects in carbon fiber reinforced polymer (CFRP laminates exposed to blast loading. The use of CFRP offers an attractive option for mitigating structures exposed to blasts. However, the effect of high strain rates in CFRP composites commonly used in the civil industry is unknown. This research conducted tensile tests of 21 CFRP coupons using a hydraulically powered dynamic loader. The strain rates ranged from 0.0015 s−1 to 7.86 s−1 and are representative of strain rates that CFRP may see in a blast when used to strengthen reinforced concrete structures. The results of the testing showed no increase in the tensile strength or stiffness of the CFRP at the higher strain rates. In addition, the results showed significant scatter in the tensile strengths possibly due to the rate of loading or manufacture of the coupon.

  1. Effect of pressurization on antibacterial properties of Lactobacillus strains

    Science.gov (United States)

    Jankowska, Agnieszka; Grześkiewicz, Aleksandra; Wiśniewska, Krystyna; Reps, Arnold

    2010-03-01

    The objective of the study was to determine the effect of high pressures on antibacterial properties of selected strains of the Lactobacillus species. Cultures of 22 strains were subjected to high-pressure treatment at 30, 60, 90, and 300 MPa/1 min/18 °C. The susceptibility of the bacteria pressurized at 30-90 MPa was diversified and depended on the strain and not on its species affiliation. When compared with pressures of 30-90 MPa, the pressure treatment at 300 MPa caused the inhibition of the acidifying activity of the strains analyzed. In turn, the pressures applied had no impact on the quantity of hydrogen peroxide synthesized. An increase in pressure was accompanied by a diminishing antibacterial activity of the investigated Lactobacillus strains.

  2. Modeling of Strain Effects in Multi-component Semiconductors

    Science.gov (United States)

    Arjmand, Mehrdad

    Strain affects the properties of crystalline material by changing the atomic symmetry. Controlling the strain in semiconductors helps to tune properties of material and design new material. For instance, strained semiconductor heterostructures have improved the efficiency of traditional solar cells remarkably. Another example of strain application is in electronic devices. Strained heterostructure nanowires provide a better control on electronic properties of gates used in transistors. Gate-all-around nanowires are promising candidates to power microprocessors in future. Strain is also used to make quantum dot structures from semiconductors. These quantum dots are used in quantum computing, diode lasers and sensors. Once the stored strain in a structure reaches a critical limit, it relaxes by triggering different phenomena in the structure. For instance, strain causes morphology change, plastic deformation, phase separation and intermixing, fracture, buckling, bulging and peeling. In order to use these strained structures for design purposes, it is critical to understand these different relaxation phenomena and be able to control them. Modeling provides a powerful framework to understand different relaxation mechanisms and provide guidance to control these strain induced phenomena. In this thesis, I have developed a continuum based model called "phase field" to study morphology change, plastic deformation and phase separation in multi-component semiconductors during growth and annealing processes. The advantage of phase field approach compared to some other modeling techniques is that it includes the effects of both thermodynamics and kinetics. Also, I have developed a continuum based elasto-plasticity model to study the effects of plastic relaxation in semiconductor nanowires. This model can particularly be useful for piezoelectric and surface stability analysis of nanowires.

  3. Antidepressant-Like Actions of Inhibitors of Poly(ADP-Ribose) Polymerase in Rodent Models.

    Science.gov (United States)

    Ordway, Gregory A; Szebeni, Attila; Hernandez, Liza J; Crawford, Jessica D; Szebeni, Katalin; Chandley, Michelle J; Burgess, Katherine C; Miller, Corwin; Bakkalbasi, Erol; Brown, Russell W

    2017-12-01

    Many patients suffering from depressive disorders are refractory to treatment with currently available antidepressant medications, while many more exhibit only a partial response. These factors drive research to discover new pharmacological approaches to treat depression. Numerous studies demonstrate evidence of inflammation and elevated oxidative stress in major depression. Recently, major depression has been shown to be associated with elevated levels of DNA oxidation in brain cells, accompanied by increased gene expression of the nuclear base excision repair enzyme, poly(ADP-ribose) polymerase-1. Given these findings and evidence that drugs that inhibit poly(ADP-ribose) polymerase-1 activity have antiinflammatory and neuroprotective properties, the present study was undertaken to examine the potential antidepressant properties of poly(ADP-ribose) polymerase inhibitors. Two rodent models, the Porsolt swim test and repeated exposure to psychological stressors, were used to test the poly(ADP-ribose) polymerase inhibitor, 3-aminobenzamide, for potential antidepressant activity. Another poly(ADP-ribose) polymerase inhibitor, 5-aminoisoquinolinone, was also tested. Poly(ADP-ribose) polymerase inhibitors produced antidepressant-like effects in the Porsolt swim test, decreasing immobility time, and increasing latency to immobility, similar to the effects of fluoxetine. In addition, 3-aminobenzamide treatment increased sucrose preference and social interaction times relative to vehicle-treated control rats following repeated exposure to combined social defeat and unpredictable stress, mediating effects similar to fluoxetine treatment. The poly(ADP-ribose) polymerase inhibitors 3-aminobenzamide and 5-aminoisoquinolinone exhibit antidepressant-like activity in 2 rodent stress models and uncover poly(ADP-ribose) polymerase as a unique molecular target for the potential development of a novel class of antidepressants.

  4. Raman gains of ADP and KDP crystals

    Science.gov (United States)

    Zhou, Hai-Liang; Zhang, Qing-Hua; Wang, Bo; Xu, Xin-Guang; Wang, Zheng-Ping; Sun, Xun; Zhang, Fang; Zhang, Li-Song; Liu, Bao-An; Chai, Xiang-Xu

    2015-04-01

    In this paper, the Raman gain coefficients of ammonium dihydrogen phosphate (ADP) and potassium dihydrogen phosphate (KDP) crystals are measured. By using a pump source of a 30-ps, 532-nm laser, the gain coefficients of ADP and KDP are 1.22 cm/GW, and 0.91 cm/GW, respectively. While for a 20-ps, 355-nm pump laser, the gain coefficients of these two crystals are similar, which are 1.95 cm/GW for ADP and 1.86 for KDP. The present results indicate that for ultra-violet frequency conversion, the problem of stimulated Raman scattering for ADP crystal will not be more serious than that for KDP crystal. Considering other advantages such the larger nonlinear optical coefficient, higher laser damage threshold, and lower noncritical phase-matching temperature, it can be anticipated that ADP will be a powerful competitor to KDP in large aperture, high energy third-harmonic generation or fourth-harmonic generation applications. Project supported by the National Natural Science Foundation of China (Grant Nos. 51323002 and 51402173), the Independent Innovation Foundation of Shandong University, China (Grant Nos. IIFSDU and 2012JC016), the Program for New Century Excellent Talents in University, China (Grant No. NCET-10-0552), the Fund from the Key Laboratory of Neutron Physics, China Academy of Engineering Physics (Grant No. 2014BB07), and the Natural Science Foundation for Distinguished Young Scholar of Shandong Province, China (Grant No. JQ201218).

  5. AdpC is a Prevotella intermedia 17 leucine-rich repeat internalin-like protein.

    Science.gov (United States)

    Iyer, Divya; Anaya-Bergman, Cecilia; Jones, Kevin; Yanamandra, Sai; Sengupta, Dipanwita; Miyazaki, Hiroshi; Lewis, Janina P

    2010-06-01

    The oral bacterium Prevotella intermedia attaches to and invades gingival epithelial cells, fibroblasts, and endothelial cells. Several genes encoding proteins that mediate both the adhesion and invasion processes are carried on the genome of this bacterium. Here, we characterized one such protein, AdpC, belonging to the leucine-rich repeat (LRR) protein family. Bioinformatics analysis revealed that this protein shares similarity with the Treponema pallidum LRR (LRR(TP)) family of proteins and contains six LRRs. Despite the absence of a signal peptide, this protein is localized on the bacterial outer membrane, indicating that it is transported through an atypical secretion mechanism. The recombinant form of this protein (rAdpC) was shown to bind fibrinogen. In addition, the heterologous host strain Escherichia coli BL21 expressing rAdpC (V2846) invaded fibroblast NIH 3T3 cells at a 40-fold-higher frequency than control E. coli BL21 cells expressing a sham P. intermedia 17 protein. Although similar results were obtained by using human umbilical vein endothelial cells (HUVECs), only a 3-fold-increased invasion of V2846 into oral epithelial HN4 cells was observed. Thus, AdpC-mediated invasion is cell specific. This work demonstrated that AdpC is an important invasin protein of P. intermedia 17.

  6. AdpC Is a Prevotella intermedia 17 Leucine-Rich Repeat Internalin-Like Protein▿

    Science.gov (United States)

    Iyer, Divya; Anaya-Bergman, Cecilia; Jones, Kevin; Yanamandra, Sai; Sengupta, Dipanwita; Miyazaki, Hiroshi; Lewis, Janina P.

    2010-01-01

    The oral bacterium Prevotella intermedia attaches to and invades gingival epithelial cells, fibroblasts, and endothelial cells. Several genes encoding proteins that mediate both the adhesion and invasion processes are carried on the genome of this bacterium. Here, we characterized one such protein, AdpC, belonging to the leucine-rich repeat (LRR) protein family. Bioinformatics analysis revealed that this protein shares similarity with the Treponema pallidum LRR (LRRTP) family of proteins and contains six LRRs. Despite the absence of a signal peptide, this protein is localized on the bacterial outer membrane, indicating that it is transported through an atypical secretion mechanism. The recombinant form of this protein (rAdpC) was shown to bind fibrinogen. In addition, the heterologous host strain Escherichia coli BL21 expressing rAdpC (V2846) invaded fibroblast NIH 3T3 cells at a 40-fold-higher frequency than control E. coli BL21 cells expressing a sham P. intermedia 17 protein. Although similar results were obtained by using human umbilical vein endothelial cells (HUVECs), only a 3-fold-increased invasion of V2846 into oral epithelial HN4 cells was observed. Thus, AdpC-mediated invasion is cell specific. This work demonstrated that AdpC is an important invasin protein of P. intermedia 17. PMID:20308299

  7. Strain effects on anisotropic magnetoresistance in a nanowire spin valve

    Science.gov (United States)

    Hossain, Md I.; Maksud, M.; Subramanian, A.; Atulasimha, J.; Bandyopadhyay, S.

    2016-11-01

    The longitudinal magnetoresistance of a copper nanowire contacted by two cobalt contacts shows broad spin-valve peaks at room temperature. However, when the contacts are slightly heated, the peaks change into troughs which are signature of anisotropic magnetoresistance (AMR). Under heating, the differential thermal expansion of the contacts and the substrate generates a small strain in the cobalt contacts which enhances the AMR effect sufficiently to change the peak into a trough. This shows the extreme sensitivity of AMR to strain. The change in the AMR resistivity coefficient due to strain is estimated to be a few m Ω -m/microstrain.

  8. The Effects of Thermal Strain on Cognition

    National Research Council Canada - National Science Library

    Hocking, Chris

    2000-01-01

    ...). The hot and humid conditions are known to cause debilitating effects on soldiers deployed to northern regions of Australia, with the consequence that the effectiveness and efficiency of operations...

  9. Fracture of anisotropic materials with plastic strain-gradient effects

    DEFF Research Database (Denmark)

    Legarth, Brian Nyvang

    2013-01-01

    A unit cell is adopted to numerically analyze the effect of plastic anisotropy on frac-ture evolution in a micro-reinforced fiber-composite. The matrix material exhibit size-effects and an anisotropic strain-gradient plasticity model accounting for such size-effects through a mate-rial length scale...

  10. Strain effects on the work function of an organic semiconductor

    KAUST Repository

    Wu, Yanfei

    2016-02-01

    Establishing fundamental relationships between strain and work function (WF) in organic semiconductors is important not only for understanding electrical properties of organic thin films, which are subject to both intrinsic and extrinsic strains, but also for developing flexible electronic devices. Here we investigate tensile and compressive strain effects on the WF of rubrene single crystals. Mechanical strain induced by thermal expansion mismatch between the substrate and rubrene is quantified by X-ray diffraction. The corresponding WF change is measured by scanning Kelvin probe microscopy. The WF of rubrene increases (decreases) significantly with in-plane tensile (compressive) strain, which agrees qualitatively with density functional theory calculations. An elastic-to-plastic transition, characterized by a steep rise of the WF, occurs at ~0.05% tensile strain along the rubrene π-stacking direction. The results provide the first concrete link between mechanical strain and WF of an organic semiconductor and have important implications for understanding the connection between structural and electronic disorder in soft organic electronic materials.

  11. Effective stress coefficient for uniaxial strain condition

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Fabricius, Ida Lykke

    2012-01-01

    The effective stress coefficient, introduced by Biot, is used for predicting effective stress or pore pressure in the subsurface. It is not a constant value. It is different for different types of sediment and it is stress dependent. We used a model, based on contact between the grains to describe...

  12. ADP stimulation of inositol phosphates in hepatocytes: role of conversion to ATP and stimulation of P2Y2 receptors.

    Science.gov (United States)

    Dixon, C Jane; Hall, John F; Boarder, Michael R

    2003-01-01

    1 Accumulation of inositol (poly)phosphates (InsP(x)) has been studied in rat hepatocytes labelled with [(3)H]inositol. Stimulation with ADP resulted in a significant increase in total [(3)H]InsP(x), whereas 2-MeSADP had only a small effect and ADPbetaS was ineffective. UTP and ITP also stimulated substantial increases in [(3)H]InsP(x). 2 The dose-response curve to ADP was largely unaltered by the presence of the P2Y(1) antagonist, adenosine-3'-phosphate-5'-phosphate (A3P5P). Similarly, inclusion of MRS 2179, a more selective P2Y(1) antagonist, had no effect on the dose-response curve to ADP. 3 The inclusion of hexokinase in the assay reduced, but did not abolish, the response to ADP. 4 HPLC analysis revealed that ADP in the medium was rapidly converted to AMP and ATP. The inclusion of hexokinase removed ATP, but exacerbated the decline in ADP concentration, leading to increased levels of AMP. 2-MeSADP was stable in the medium and ATP was largely unaffected. 5 The addition of the adenylate kinase inhibitor, diadenosine pentaphosphate (Ap(5)A) significantly reduced the ADP response. HPLC analysis conducted in parallel demonstrated that this treatment inhibited conversion of ADP to ATP and AMP. 6 Inclusion of the P1 antagonist CGS 15943 had no effect on the dose-response curve to ADP. 7 These observations indicate that hepatocytes respond to ADP with an increase in inositol (poly)phosphates following conversion to ATP. P2Y(1) activation in hepatocytes does not appear to be coupled to inositol 1,4,5-trisphosphate (Ins(1,4,5)P(3)) production.

  13. Strain gradient crystal plasticity effects on flow localization

    DEFF Research Database (Denmark)

    Borg, Ulrik

    2007-01-01

    In metal grains one of the most important failure mechanisms involves shear band localization. As the band width is small, the deformations are affected by material length scales. To study localization in single grains a rate-dependent crystal plasticity formulation for finite strains is presented...... for metals described by the reformulated Fleck-Hutchinson strain gradient plasticity theory. The theory is implemented numerically within a finite element framework using slip rate increments and displacement increments as state variables. The formulation reduces to the classical crystal plasticity theory...... in the absence of strain gradients. The model is used to study the effect of an internal material length scale on the localization of plastic flow in shear bands in a single crystal under plane strain tension. It is shown that the mesh sensitivity is removed when using the nonlocal material model considered...

  14. Antiproliferation effects and antioxidant activity of two new Lactobacillus strains

    Directory of Open Access Journals (Sweden)

    Parisa Shokryazdan

    2017-11-01

    Full Text Available Abstract The microorganisms most commonly used as probiotics are lactic acid bacteria, especially those of the genus Lactobacillus. In the present study, two Lactobacillus strains, L. pentosus ITA23 and L. acidipiscis ITA44, previously isolated from mulberry silage, were characterized for their antiproliferative and antioxidant activities. The antiproliferative effects of the strains were investigated using the MTT assay with breast cancer (MDA-MB-231, liver cancer (HepG2 and normal liver (Chang cell lines. The strains were tested for their antioxidant activity using the FRAP and ABTS methods. The results showed that the two Lactobacillus strains had good antiproliferative effects against both cancer cell lines tested, while their effects on the normal cells were weak. Based on the results of the antioxidant tests, the intact cells and cell-free extracts of the two Lactobacillus strains showed more than 135 and less than 50 µg trolox/ml of antioxidant activity, respectively. Lactobacillus pentosus ITA23 and L. acidipiscis ITA44 can be considered as potential probiotic candidates for humans because of their antioxidant activity and antiproliferation effects against cancer cells.

  15. ADP Security Plan, Math Building, Room 1139

    Energy Technology Data Exchange (ETDEWEB)

    Melton, R.

    1985-08-27

    This document provides the draft copy of an updated (ADP) Security Plan for an IBM Personal Computer to be used in the Math Building at PNL for classified data base management. Using the equipment specified in this document and implementing the administrative and physical procedures as outlined will provide the secure environment necessary for this work to proceed.

  16. Reversible mono-ADP-ribosylation of DNA breaks.

    Science.gov (United States)

    Munnur, Deeksha; Ahel, Ivan

    2017-12-01

    Adenosine diphosphate (ADP)-ribosylation is a chemical modification of macromolecules that plays an important role in regulation of quintessential biological processes such as DNA repair, transcription, chromatin remodelling, stress response, apoptosis, bacterial metabolism and many others. ADP-ribosylation is carried out by ADP-ribosyltransferase proteins, such as poly (ADP-ribose) polymerases (PARPs) that transfer either monomer or polymers of ADP-ribose onto the molecular targets by using nicotinamide adenine dinucleotide (NAD + ) as a cofactor. Traditionally, proteins have been described as primary targets of ADP-ribosylation; however, there has been growing evidence that DNA may be a common target as well. Here, we show using biochemical studies that PARP3, a DNA damage-activated ADP-ribosyltransferase, can mono-ADP-ribosylate double-stranded DNA ends. ADP-ribosylation of DNA mediated by PARP3 attaches a single mono-ADP-ribose moiety to the phosphate group at the terminal ends of DNA. We further show that mono ADP-ribosylation at DNA ends can be efficiently reversed by several cellular hydrolases (PARG, MACROD2, TARG1 and ARH3). This suggests that mono ADP-ribosylated DNA adducts can be efficiently removed in cells by several mechanisms. © 2017 The Authors. The FEBS Journal published by John Wiley & Sons Ltd on behalf of Federation of European Biochemical Societies.

  17. Genes regulation encoding ADP/ATP carrier in yeasts Saccharomyces cerevisiae and Candida parapsilosis

    International Nuclear Information System (INIS)

    Nebohacova, M.

    2000-01-01

    Genes encoding a mitochondrial ADP/ATP carrier (AAC) in yeast Saccharomyces cerevisiae and Candida parapsilosis were investigated. AAC2 is coding for the major AAC isoform in S. cerevisiae. We suggest that AAC2 is a member of a syn-expression group of genes encoding oxidative phosphorylation proteins. Within our previous studies on the regulation of the AAC2 transcription an UAS (-393/-268) was identified that is essential for the expression of this gene. Two functional regulatory cis-elements are located within this UAS -binding sites for an ABFl factor and for HAP2/3/4/5 heteromeric complex. We examined relative contributions and mutual interactions of the ABFl and HAP2/3/4/5 factors in the activation of transcription from the UAS of the AAC2 gene. The whole UAS was dissected into smaller sub-fragments and tested for (i) the ability to form DNA-protein complexes with cellular proteins in vitro, (ii) the ability to confer heterologous expression using AAC3 gene lacking its own promoter, and (iii) the expression of AAC3-lacZ fusion instead of intact AAC3 gene. The obtained results demonstrated that: a) The whole UAS as well as sub-fragment containing only ABF1-binding site are able to form DNA-protein complexes with cellular proteins in oxygen- and heme- dependent manner. The experiments with antibody against the ABF1 showed that the ABF1 factor is one of the proteins binding to AAC2 promoter. We have been unsuccessful to prove the binding of cellular proteins to the HAP2/3/4/5-binding site. However, the presence of HAP2/3/4/5-binding site is necessary to drive a binding of cellular proteins to the ABF1-binding site in carbon source-dependent manner. b) The presence of both ABF1- and HAP2/3/4/5-binding sites and original spacing between them is necessary to confer the growth of Aaac2 mutant strain on non- fermentable carbon source when put in front of AAC3 gene introduced on centromeric vector to Aaac2 mutant strain. c) For the activation of AAC3-lacZ expression on

  18. Roles of Asp179 and Glu270 in ADP-Ribosylation of Actin by Clostridium perfringens Iota Toxin.

    Directory of Open Access Journals (Sweden)

    Alexander Belyy

    Full Text Available Clostridium perfringens iota toxin is a binary toxin composed of the enzymatically active component Ia and receptor binding component Ib. Ia is an ADP-ribosyltransferase, which modifies Arg177 of actin. The previously determined crystal structure of the actin-Ia complex suggested involvement of Asp179 of actin in the ADP-ribosylation reaction. To gain more insights into the structural requirements of actin to serve as a substrate for toxin-catalyzed ADP-ribosylation, we engineered Saccharomyces cerevisiae strains, in which wild type actin was replaced by actin variants with substitutions in residues located on the Ia-actin interface. Expression of the actin mutant Arg177Lys resulted in complete resistance towards Ia. Actin mutation of Asp179 did not change Ia-induced ADP-ribosylation and growth inhibition of S. cerevisiae. By contrast, substitution of Glu270 of actin inhibited the toxic action of Ia and the ADP-ribosylation of actin. In vitro transcribed/translated human β-actin confirmed the crucial role of Glu270 in ADP-ribosylation of actin by Ia.

  19. Demonstrating Effectiveness of Antibiotics Against Known Bacteria Strains

    Science.gov (United States)

    Keefe, Lois M.

    1977-01-01

    Procedures are described for showing the effectiveness of antibiotics (penicillin, ampicillin, and tetracycline) against a nonpathogenic bacteria strain (Bacillus cereus). Methods are outlined for preparing nutrient agar, sterilizing tubes, pouring agar plates, preparing antibiotic discs, and transferring antibiotic discs to agar plates. (CS)

  20. Inverse Funnel Effect of Excitons in Strained Black Phosphorus

    Directory of Open Access Journals (Sweden)

    Pablo San-Jose

    2016-09-01

    Full Text Available We study the effects of strain on the properties and dynamics of Wannier excitons in monolayer (phosphorene and few-layer black phosphorus (BP, a promising two-dimensional material for optoelectronic applications due to its high mobility, mechanical strength, and strain-tunable direct band gap. We compare the results to the case of molybdenum disulphide (MoS_{2} monolayers. We find that the so-called funnel effect, i.e., the possibility of controlling exciton motion by means of inhomogeneous strains, is much stronger in few-layer BP than in MoS_{2} monolayers and, crucially, is of opposite sign. Instead of excitons accumulating isotropically around regions of high tensile strain like in MoS_{2}, excitons in BP are pushed away from said regions. This inverse funnel effect is moreover highly anisotropic, with much larger funnel distances along the armchair crystallographic direction, leading to a directional focusing of exciton flow. A strong inverse funnel effect could enable simpler designs of funnel solar cells and offer new possibilities for the manipulation and harvesting of light.

  1. Symbiotic effectiveness of acid-tolerant Bradyrhizobium strains with ...

    African Journals Online (AJOL)

    Further, symbiotic effectiveness of these strains was determined under the polyhouse conditions in sterilized soil (pH 4.5). Highest and lowest symbiotic characters, dry matter production and nitrogen improvement per plant were observed in PSR001 and NSR008 inoculated plants, respectively. All the examined isolates ...

  2. Effect of Selected Azotobacter Bacterial Strains on the Enrichment of ...

    African Journals Online (AJOL)

    Target Audience: Local farmers, Livestock researchers, microbiologist. The effect of three different strains of Azotobacter bacteria in solid substrate fermentation on cassava waste was evaluated. The substrate was incubated at 300c for 10 days inoculation with the Azotobacter bacteria species. One non-inoculated batch ...

  3. STRAIN RATE EFFECT ON THE FAILURE STRAIN AND HARDNESS OF METALLIC ARMOR PLATES SUBJECTED TO HIGH VELOCITY PROJECTILE IMPACT

    Directory of Open Access Journals (Sweden)

    QASIM H. SHAH

    2006-12-01

    Full Text Available Post impact strain measurements of damaged plates were carried out experimentally after launching a spherical steel projectile at varying velocities against a fixed thin plate targets made of copper and steel materials and constrained at their outer periphery. Penetration or partial perforation of the target plates was achieved for projectile velocities of 120 m/s. The strain rates achieved during the experiments varied from 8000s-1 to 15000 s-1 for steel specimens and from 9000 s-1 to 19000 s-1 for copper specimens for the projectile speeds of 68 to 120 m/s. Strain measurements for static and dynamic loading showed that steel deformation is excessive before failure resulting in higher failure strain at high strain rates while the failure strain for copper at high loading rates causes separation of material before reaching very large strains. At the same loading rates the plate thinning of steel was recorded to be severe than copper. Hardness values of materials subjected to high strain rate were measured experimentally showing a strong dependency upon strain rates calculated by using LS-DYNA software. Strain rate effect on the failure strain of metals was investigated.

  4. Strain effects in freestanding three-dimensional nitride nanostructures

    Energy Technology Data Exchange (ETDEWEB)

    Povolotskyi, Michael; Auf der Maur, Matthias; Di Carlo, Aldo [MINAS Lab., Department of Electronic Engeneering, University of Rome ' ' Tor Vergata' ' , via del Politecnico, 1, 00133 Rome (Italy)

    2005-11-01

    Nitride based heterostructures of nanometer size have been studied. A theoretical model is presented that allows to study strain in lattice mismatched three-dimensional freestanding heterostructures. The model has been applied to an AlGaN/GaN quantum well structure. We computed a strain pattern that is found to be highly nonhomogeneous. Effect of strain on the band structure has been studied considering piezoelectric field and deformation potential. We calculated energy and oscillator strength of the fundamental optical transition in different regions of the structure in order to estimate the intrinsic broadening of a spectral line. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  5. On the kinetic and allosteric regulatory properties of the ADP-glucose pyrophosphorylase from Rhodococcus jostii: An approach to evaluate glycogen metabolism in oleaginous bacteria

    Directory of Open Access Journals (Sweden)

    Antonela Estefanía Cereijo

    2016-06-01

    Full Text Available Rhodococcus spp. are oleaginous bacteria that accumulate glycogen during exponential growth. Despite the importance of these microorganisms in biotechnology, little is known about the regulation of carbon and energy storage, mainly the relationship between glycogen and triacilglycerols metabolisms. Herein we report the molecular cloning and heterologous expression of the gene coding for ADP-glucose pyrophosphorylase (EC 2.7.7.27 of Rhodococcus jostii, strain RHA1. The recombinant enzyme was purified to electrophoretic homogeneity to accurately characterize its oligomeric, kinetic and regulatory properties. The R. jostii ADP-glucose pyrophosphorylase is a homotetramer of 190 kDa exhibiting low basal activity to catalyze synthesis of ADP-glucose, which is markedly influenced by different allosteric effectors. Glucose-6P, mannose-6P, fructose-6P, ribose-5P and phosphoenolpyruvate were major activators; whereas NADPH and 6P-gluconate behaved as main inhibitors of the enzyme. The combination of glucose-6P and other effectors (activators or inhibitors showed a cross-talk effect suggesting that the different metabolites could orchestrate a fine regulation of ADP-glucose pyrophosphorylase in R. jostii. The enzyme exhibited some degree of affinity toward ATP, GTP, CTP, and other sugar 1P substrates. Remarkably, the use of glucosamine-1P was sensitive to allosteric activation. The relevance of the fine regulation of R. jostii ADP-glucose pyrophosphorylase is further analyzed in the framework of proteomic studies already determined for the bacterium. Results support a critical role for glycogen as a temporal reserve that provides a pool of carbon able of be re-routed to produce long-term storage of lipids under certain conditions.

  6. NADP+ enhances cholera and pertussis toxin-catalyzed ADP-ribosylation of membrane proteins

    International Nuclear Information System (INIS)

    Kawai, Y.; Whitsel, C.; Arinze, I.J.

    1986-01-01

    Cholera or pertussis toxin-catalyzed [ 32 P]ADP-ribosylation is frequently used to estimate the concentration of the stimulatory (Ns) or inhibitory (Ni) guanine nucleotide regulatory proteins which modulate the activity of adenylate cyclase. With this assay, however, the degradation of the substrate, NAD + , by endogenous enzymes such as NAD + -glycohydrolase (NADase) present in the test membranes can influence the results. In this study the authors show that both cholera and pertussis toxin-catalyzed [ 32 P]ADP-ribosylation of liver membrane proteins is markedly enhanced by NADP + . The effect is concentration dependent; with 20 μM [ 32 P]NAD + as substrate maximal enhancement is obtained at 0.5-1.0 mM NADP + . The enhancement of [ 32 P]ADP-ribosylation by NADP + was much greater than that by other known effectors such as Mg 2+ , phosphate or isoniazid. The effect of NADP + on ADP-ribosylation may occur by inhibition of the degradation of NAD + probably by acting as an alternate substrate for NADase. Among inhibitors tested (NADP + , isoniazid, imidazole, nicotinamide, L-Arg-methyl-ester and HgCl 2 ) to suppress NADase activity, NADP + was the most effective and, 10 mM, inhibited activity of the enzyme by about 90%. In membranes which contain substantial activities of NADase the inclusion of NADP + in the assay is necessary to obtain maximal ADP-ribosylation

  7. Differential regulation by AMP and ADP of AMPK complexes containing different γ subunit isoforms.

    Science.gov (United States)

    Ross, Fiona A; Jensen, Thomas E; Hardie, D Grahame

    2016-01-15

    The γ subunits of heterotrimeric AMPK complexes contain the binding sites for the regulatory adenine nucleotides AMP, ADP and ATP. We addressed whether complexes containing different γ isoforms display different responses to adenine nucleotides by generating cells stably expressing FLAG-tagged versions of the γ1, γ2 or γ3 isoform. When assayed at a physiological ATP concentration (5 mM), γ1- and γ2-containing complexes were allosterically activated almost 10-fold by AMP, with EC50 values one to two orders of magnitude lower than the ATP concentration. By contrast, γ3 complexes were barely activated by AMP under these conditions, although we did observe some activation at lower ATP concentrations. Despite this, all three complexes were activated, due to increased Thr(172) phosphorylation, when cells were incubated with mitochondrial inhibitors that increase cellular AMP. With γ1 complexes, activation and Thr(172) phosphorylation induced by the upstream kinase LKB1 [liver kinase B1; but not calmodulin-dependent kinase kinase (CaMKKβ)] in cell-free assays was markedly promoted by AMP and, to a smaller extent and less potently, by ADP. However, effects of AMP or ADP on activation and phosphorylation of the γ2 and γ3 complexes were small or insignificant. Binding of AMP or ADP protected all three γ subunit complexes against inactivation by Thr(172) dephosphorylation; with γ2 complexes, ADP had similar potency to AMP, but with γ1 and γ3 complexes, ADP was less potent than AMP. Thus, AMPK complexes containing different γ subunit isoforms respond differently to changes in AMP, ADP or ATP. These differences may tune the responses of the isoforms to fit their differing physiological roles. © 2016 Authors.

  8. Strain Rate Effect on Tensile Behavior for a High Specific Strength Steel: From Quasi-Static to Intermediate Strain Rates

    OpenAIRE

    Wei Wang; Yan Ma; Muxin Yang; Ping Jiang; Fuping Yuan; Xiaolei Wu

    2017-01-01

    The strain rate effect on the tensile behaviors of a high specific strength steel (HSSS) with dual-phase microstructure has been investigated. The yield strength, the ultimate strength and the tensile toughness were all observed to increase with increasing strain rates at the range of 0.0006 to 56/s, rendering this HSSS as an excellent candidate for an energy absorber in the automobile industry, since vehicle crushing often happens at intermediate strain rates. Back stress hardening has been ...

  9. Hsp90 Sensitivity to ADP Reveals Hidden Regulation Mechanisms.

    Science.gov (United States)

    Halpin, Jackson C; Street, Timothy O

    2017-09-15

    The ATPase cycle of the Hsp90 molecular chaperone is essential for maintaining the stability of numerous client proteins. Extensive analysis has focused on ATP-driven conformational changes of Hsp90; however, little is known about how Hsp90 operates under physiological nucleotide conditions in which both ATP and ADP are present. By quantifying Hsp90 activity under mixed nucleotide conditions, we find dramatic differences in ADP sensitivity among Hsp90 homologs. ADP acts as a strong ATPase inhibitor of cytosol-specific Hsp90 homologs, whereas organellular Hsp90 homologs (Grp94 and TRAP1) are relatively insensitive to the presence of ADP. These results imply that an ATP/ADP heterodimer of cytosolic Hsp90 is the predominant active state under physiological nucleotide conditions. ADP inhibition of human and yeast cytosolic Hsp90 can be relieved by the cochaperone aha1. ADP inhibition of bacterial Hsp90 can be relieved by bacterial Hsp70 and an activating client protein. These results suggest that altering ADP inhibition may be a mechanism of Hsp90 regulation. To determine the molecular origin of ADP inhibition, we identify residues that preferentially stabilize either ATP or ADP. Mutations at these sites can both increase and decrease ADP inhibition. An accounting of ADP is critically important for designing and interpreting experiments with Hsp90. For example, contaminating ADP is a confounding factor in fluorescence resonance energy transfer experiments measuring arm closure rates of Hsp90. Our observations suggest that ADP at physiological levels is important to Hsp90 structure, activity, and regulation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. LYOPHILIZATION EFFECT ON PRODUCTIVITY OF BUTANOL-PRODUCING STRAINS

    Directory of Open Access Journals (Sweden)

    O. O. Tigunova

    2016-10-01

    Full Text Available Investigation of lyophilization effect on the productivity of butanol-producing strains was the aim of our research. For this purpose we used butanol-producing strains; technical glycerol; biomass of switchgrass Panicum virgatum L. Lyophilization was performed using a lyophilization-drying. The effect of the protective medium on residual moisture of freezedrying cultures suspensions depending on the concentration of glucose and sucrose was studed. It was shown that the lowest residual moisture was attained by using glucose and sucrose in amount of 10% and if the samples of freeze-drying bacteria had been saved for one month at 4 οC the productivity did not decrease. As temperature preservation was increased the productivity of the cultures was gradually decreased and it was greatly reduced at 30 οC. So the protective medium composition was optimized for lyophilization of butanol-producing strains as follows: sucrose 10.0%; gelatin 10.0%; agar 0.02%. It was shown that the preservation of samples of freeze-drying bacteria for six months at a temperature of 4 οC did not affect the productivity of strains. It was found that cultures could use glycerol as a carbon source for butanol accumulation before lyophilization.

  11. Stress-Softening and Residual Strain Effects in Suture Materials

    Directory of Open Access Journals (Sweden)

    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.

  12. Effects of gauge volume on pseudo-strain induced in strain measurement using time-of-flight neutron diffraction

    Science.gov (United States)

    Suzuki, Hiroshi; Harjo, Stefanus; Abe, Jun; Xu, Pingguang; Aizawa, Kazuya; Akita, Koichi

    2013-07-01

    Spurious or pseudo-strains observed in time-of-flight (TOF) neutron diffraction due to neutron attenuation, surface-effects and a strain distribution within the gauge volume were investigated. Experiments were carried out on annealed and bent ferritic steel bars to test these effects. The most representative position in the gauge volume corresponds to the neutron-weighted center of gravity (ncog), which takes into account variations in intensity within the gauge volume due to neutron attenuation and/or absence of material in the gauge volume. The average strain in the gauge volume was observed to be weighted towards the ncog position but following an increase in the size of the gauge volume the weighted average strain was changed because of the change in the ncog position when a strain gradient appeared within the gauge volume. On the other hand, typical pseudo-strains, which are well known, did appear in through-surface strain measurements when the gauge volume was incompletely filled by the sample. Tensile pseudo-strains due to the surface-effect increased near the sample surface and exhibited a similar trend regardless of the size of the gauge volume, while the pseudo-strains increased faster for the smaller gauge volume. Furthermore, a pseudo-strain due to a change in the ncog position was observed even when the gauge volume was perfectly filled in the sample, and it increased with an increase in the size of the gauge volume. These pseudo-strains measured were much larger than those simulated by the conventional modeling, whereas they were simulated by taking into account an incident neutron beam divergence additionally in the model. Therefore, the incident divergence of the incident neutron beam must be carefully designed to avoid pseudo-strains in time-of-flight neutron diffractometry.

  13. Gender and General Strain Theory: A Comparison of Strains, Mediating, and Moderating Effects Explaining Three Types of Delinquency

    Science.gov (United States)

    Moon, Byongook; Morash, Merry

    2017-01-01

    The present study of 659 Korean adolescents tests General Strain Theory's (GST) utility in explaining gender differences in delinquency causation. It models the effects of key strains, negative emotions, and a composite measure of several conditioning factors separately for boys and girls and for delinquency. Consistent with the theory, males and…

  14. Strain effects in polytypical wurtzite/zinc-blend nanowhiskers

    Science.gov (United States)

    Sipahi, Guilherme; Faria, Paulo

    2012-02-01

    The recent interest on III-V nanowhiskers has led to the growth of high quality samples of systems with two different crystalline structures [1]. The crystals grown in [111]-direction for the zinc-blend (ZB) phase and [0001]-direction for the wurtzite (WZ) phase are very similar and can both be described as stacked hexagonal layers. The effect of two different structural phases coexisting in the same nanostrucure is known as polytypism and creates confinement profiles similar to a heterostructure. One can notice band offsets at the interface and the formation of electronic minibands that can be explored to design systems for device applications. Although some of the III-V compounds do not present WZ structure in bulk form, recent calculations [2] presented a theoretical prediction of their band structure. However, as they considered that ZB and WZ to have the same lattice parameters no strain effects should appear on a first approach. Our theoretical approach introduces strain effects in our previous model [3] by using group theory arguments. It allows the analysis of the biaxial strain effects for both structures in a single matrix. [1] P. Caroff et al. Nature Nanotech. 4, 50, 2009. [2] A. De and C. E. Pryor, Phys. Rev. B 81, 155210, 2010 [3] http://arxiv.org/abs/1012.022

  15. Macrodomain-containing proteins are new mono-ADP-ribosylhydrolases.

    Science.gov (United States)

    Rosenthal, Florian; Feijs, Karla L H; Frugier, Emilie; Bonalli, Mario; Forst, Alexandra H; Imhof, Ralph; Winkler, Hans C; Fischer, David; Caflisch, Amedeo; Hassa, Paul O; Lüscher, Bernhard; Hottiger, Michael O

    2013-04-01

    ADP-ribosylation is an important post-translational protein modification (PTM) that regulates diverse biological processes. ADP-ribosyltransferase diphtheria toxin-like 10 (ARTD10, also known as PARP10) mono-ADP-ribosylates acidic side chains and is one of eighteen ADP-ribosyltransferases that catalyze mono- or poly-ADP-ribosylation of target proteins. Currently, no enzyme is known that reverses ARTD10-catalyzed mono-ADP-ribosylation. Here we report that ARTD10-modified targets are substrates for the macrodomain proteins MacroD1, MacroD2 and C6orf130 from Homo sapiens as well as for the macrodomain protein Af1521 from archaebacteria. Structural modeling and mutagenesis of MacroD1 and MacroD2 revealed a common core structure with Asp102 and His106 of MacroD2 implicated in the hydrolytic reaction. Notably, MacroD2 reversed the ARTD10-catalyzed, mono-ADP-ribose-mediated inhibition of glycogen synthase kinase 3β (GSK3β) in vitro and in cells, thus underlining the physiological and regulatory importance of mono-ADP-ribosylhydrolase activity. Our results establish macrodomain-containing proteins as mono-ADP-ribosylhydrolases and define a class of enzymes that renders mono-ADP-ribosylation a reversible modification.

  16. Strain gradient plasticity effects in whisker-reinforced metals

    DEFF Research Database (Denmark)

    Niordson, Christian Frithiof

    2003-01-01

    A metal reinforced by fibers in the micron range is studied using the strain gradient plasticity theory of Fleck and Hutchinson (J. Mech. Phys. Solids 49 (2001) 2245). Cell-model analyses are used to study the influence of the material length parameters numerically, for both a single parameter...... version and the multiparameter theory, and significant differences between the predictions of the two models are reported. It is shown that modeling fiber elasticity is important when using the present theories. A significant stiffening effect when compared to conventional models is predicted, which...... is a result of a significant decrease in the level of plastic strain. Moreover, it is shown that the relative stiffening effect increases with fiber volume fraction. The higher-order nature of the theories allows for different higher-order boundary conditions at the fiber-matrix interface, and these boundary...

  17. Strain Rate Effect on Tensile Behavior for a High Specific Strength Steel: From Quasi-Static to Intermediate Strain Rates

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2017-12-01

    Full Text Available The strain rate effect on the tensile behaviors of a high specific strength steel (HSSS with dual-phase microstructure has been investigated. The yield strength, the ultimate strength and the tensile toughness were all observed to increase with increasing strain rates at the range of 0.0006 to 56/s, rendering this HSSS as an excellent candidate for an energy absorber in the automobile industry, since vehicle crushing often happens at intermediate strain rates. Back stress hardening has been found to play an important role for this HSSS due to load transfer and strain partitioning between two phases, and a higher strain rate could cause even higher strain partitioning in the softer austenite grains, delaying the deformation instability. Deformation twins are observed in the austenite grains at all strain rates to facilitate the uniform tensile deformation. The B2 phase (FeAl intermetallic compound is less deformable at higher strain rates, resulting in easier brittle fracture in B2 particles, smaller dimple size and a higher density of phase interfaces in final fracture surfaces. Thus, more energy need be consumed during the final fracture for the experiments conducted at higher strain rates, resulting in better tensile toughness.

  18. General Friction Model Extended by the Effect of Strain Hardening

    DEFF Research Database (Denmark)

    Nielsen, Chris V.; Martins, Paulo A.F.; Bay, Niels

    2016-01-01

    An extension to the general friction model proposed by Wanheim and Bay [1] to include the effect of strain hardening is proposed. The friction model relates the friction stress to the fraction of real contact area by a friction factor under steady state sliding. The original model for the real...... contact area as function of the normalized contact pressure is based on slip-line analysis and hence on the assumption of rigid-ideally plastic material behavior. In the present work, a general finite element model is established to, firstly, reproduce the original model under the assumption of rigid......-ideally plastic material, and secondly, to extend the solution by the influence of material strain hardening. This corresponds to adding a new variable and, therefore, a new axis to the general friction model. The resulting model is presented in a combined function suitable for e.g. finite element modeling...

  19. ADP Analysis project for the Human Resources Management Division

    Science.gov (United States)

    Tureman, Robert L., Jr.

    1993-01-01

    The ADP (Automated Data Processing) Analysis Project was conducted for the Human Resources Management Division (HRMD) of NASA's Langley Research Center. The three major areas of work in the project were computer support, automated inventory analysis, and an ADP study for the Division. The goal of the computer support work was to determine automation needs of Division personnel and help them solve computing problems. The goal of automated inventory analysis was to find a way to analyze installed software and usage on a Macintosh. Finally, the ADP functional systems study for the Division was designed to assess future HRMD needs concerning ADP organization and activities.

  20. Interaction of ADP, atractyloside, and gummiferin on the ADP translocase of the inner mitochondrial membrane

    Energy Technology Data Exchange (ETDEWEB)

    Vignais, P.V.; Vignais, P.M.; Defaye, G.; Lauquin, G.; Doussiere, J.; Chabert, J.; Brandolin, G.

    1972-05-01

    From international conference on mechanism in bioenergetica; Bari, Italy (1 May 1972). Two specific inhibitors of the adenine nucleotide translocation, gummiferin (GUM), identified to 4-carboxyatractyloside and atractyloside (ATR), were labeled with /sup 35/S and their binding properties to whole mitochondria and inner mitochondrial membrane vesicles used to monitor changes of membrane conformation induced by ADP. (auth)

  1. Effects of orientation on hardness, strain accumulation, and fracture

    Energy Technology Data Exchange (ETDEWEB)

    Suresh, K.S., E-mail: santharamsuresh@gmail.com; Kitashima, T.; Yamabe-Mitarai, Y.

    2014-11-17

    Effects of orientation on mechanical properties of near α titanium alloy IMI834 have been investigated. Orientation dependent hardness was characterized by micro hardness testing and electron back scattered diffraction (EBSD). Strain accumulation of samples subjected to tensile, compression and Charpy impact tests at room temperature and at 650 °C was analyzed using EBSD. The [0001] orientation shows the highest hardness; lower values of hardness occurred for orientations along the [101{sup ¯}0][312{sup ¯}0] axis. Differences in hardness between different orientations were discussed based on the activation of different slip and twinning systems. During tensile and Charpy impact tests at both temperatures, localized deformations restricted the strain accumulation at regions farther from the fracture surface. In both high-temperature tensile and compression tests, large orientation gradients occurred primarily at grains having lower hardness; however, the converse was not true. Apart from grain orientation, orientations of neighboring grains also have a strong influence on the development of orientation gradient. Irrespective of the test conditions and orientation, twinned regions accommodate considerably less strain and orientation gradient compared with those of the surrounding matrix.

  2. Effects of C and Si on strain aging of strain-based API X60 pipeline steels

    Science.gov (United States)

    Sung, Hyo Kyung; Lee, Dong Ho; Lee, Sunghak; Lee, Byeong-Joo; Hong, Seung-Pyo; Kim, Young-Woon; Yoo, Jang Yong; Hwang, Byoungchul; Shin, Sang Yong

    2017-05-01

    Four types of strain-based API X60 pipeline steels were fabricated by varying the C and Si contents, and the effects of C and Si on strain aging were investigated. The 0.05 wt% C steels consisted mainly of polygonal ferrite (PF), whereas the 0.08 wt% C steels consisted of acicular ferrite (AF). The volume fraction of AF increased with increasing C content because C is an austenite stabilizer element. The volume fractions of bainitic ferrite (BF) of the 0.15 wt% Si steels were higher than those of the 0.25 wt% Si steels, whereas the volume fractions of the secondary phases were lower. From the tensile properties before and after the aging process of the strainbased API X60 pipeline steels, the yield strength increased and the uniform and total elongation decreased, which is the strain aging effect. The strain aging effect in the strain-based API X60 pipeline steels was minimized when the volume fraction of AF was increased and secondary phases were distributed uniformly. On the other hand, an excessively high C content formed fine precipitates, and the strain aging effect occurred because of the interactions among dislocations and fine precipitates.

  3. Order effects on low cycle fatigue at various strain levels

    International Nuclear Information System (INIS)

    Del Puglia, A.; Pratesi, F.; Tesi, B.; Bacci, T.

    1985-01-01

    Ongoing research is currently underway to investigate the thorny problem of how damage originates and accumulates as a result of low-cycle fatigue. This communication describes testing conducted on specimens cut from bars of commercial AISI 304 stainless steel tubing subjected to a constant bending moment at room temperature. A specially-designed test apparatus allowed determination of specimen strength at both one and two strain levels, thereby confirming the presence of the loading effect. Lastly, crack concentration and depth were measured and correlated to physical damage evolution. (orig.)

  4. Effect of probiotic Lactobacillus strains in children with atopic dermatitis

    DEFF Research Database (Denmark)

    Rosenfeldt, Vibeke; Benfeldt, Eva; Nielsen, Susanne Dam

    2003-01-01

    : In a double-blind, placebo-controlled, crossover study, 2 probiotic Lactobacillus strains (lyophilized Lactobacillus rhamnosus 19070-2 and Lactobacillus reuteri DSM 122460) were given in combination for 6 weeks to 1- to 13-year-old children with AD. The patients' evaluations were registered after each......). No significant changes in the production of the cytokines IL-2, IL-4, IL-10, or IFN-gamma were found. CONCLUSIONS: A combination of L rhamnosus 19070-2 and L reuteri DSM 122460 was beneficial in the management of AD. The effect was more pronounced in patients with a positive skin prick test response...

  5. Mean strain effects on the random cyclic strain-life relations of 0Cr18Ni10Ti pipe steel

    International Nuclear Information System (INIS)

    Zhao Yongxiang; Yang Bing

    2005-01-01

    Experimental study is performed on the mean strain effects on the random cyclic strain-life relations of the new nuclear material, 0Cr18Ni10Ti pipe steel. In order to save costs of specimens and tests, an improved maximum likelihood fatigue test method is applied to manage the present strain-controlled fatigue tests. Six straining ratios, respectively, -1, -0.52, 0.22, 0.029, 0.18, and 0.48, are applied to study the effects. Total 104 specimens are fatigued. Since the material exhibits an entirely relaxation effect of mean stress under the six ratios and, in addition, there is no effectively method for the description of the mean straining effects under this case, previous Zhao's random strain-life relations are therefore applied for effective characterization of the scattering test data under the six ratios on a basis of Coffin-Manson equation.Then the effects of the ratios are analyzed respectively on the average fatigue lives, the standard deviations of the logarithms of fatigue lives, and the fatigue lives under different survival probabilities and confidences. The results reveal that the ratios greater than zero exhibit a positive effect of about 1.3 to 1.6 times under the survival probability of 0.999 and the confidence of 95%. A negative effect is exhibited for the case of the ratios less than zero. In addition, the assessment of the effects from the sense of average fatigue lives might result in a wrong conclusion for the practice of higher reliabilities. The effects can be appropriately assessed from a probabilistic sense to take into account the average lives, the scattering regularity of test data, and the size of sampling. (author)

  6. Effects of strain and strain-induced α'-martensite on passive films in AISI 304 austenitic stainless steel.

    Science.gov (United States)

    Lv, Jinlong; Luo, Hongyun

    2014-01-01

    In this paper, the effects of strain and heat treatment on strain-induced α'-martensite of AISI 304 stainless steel tubes were measured by X-ray diffraction. Moreover, the effects of strain and content of α'-martensite on passivated property on the surface of the material in borate buffer solution were evaluated by electrochemical technique. The results showed that the volume fraction of α'-martensite increased gradually with the increase of tensile strain for as-received and solid solution samples. However, α'-martensite in as-received sample was more than that in the solid solution sample. The electrochemical impedance spectroscopy results showed that the solid solution treatment improved corrosion resistance of the steel, especially for samples with small strain. Moreover, acceptor densities were always higher than donor densities for as-received and solid solution samples. With the increase of strain, the increase tendency of acceptor density was more significant than that of donor density. We also found that the total density of the acceptor and donor almost increased linearly with the increase of α'-martensite. The present results indicated that the increased acceptor density might lead to the decreased corrosion resistance of the steel. © 2013.

  7. The effect of flexoelectricity on the dielectric properties of inhomogeneously strained ferroelectric thin films

    NARCIS (Netherlands)

    Catalan, G; Sinnamon, LJ; Gregg, JM

    2004-01-01

    Recent experimental measurements of large flexoelectric coefficients in ferroelectric ceramics suggest that strain gradients can affect the polarization and permittivity behaviour of inhomogeneously strained ferroelectrics. Here we present a phenomenological model of the effect of flexoelectricity

  8. Modeling of strain effects on the device behaviors of ferroelectric memory field-effect transistors

    International Nuclear Information System (INIS)

    Yang, Feng; Hu, Guangda; Wu, Weibing; Yang, Changhong; Wu, Haitao; Tang, Minghua

    2013-01-01

    The influence of strains on the channel current–gate voltage behaviors and memory windows of ferroelectric memory field-effect transistors (FeMFETs) were studied using an improved model based on the Landau–Devonshire theory. ‘Channel potential–gate voltage’ ferroelectric polarization and silicon surface potential diagrams were constructed for strained single-domain BaTiO 3 FeMFETs. The compressive strains can increase (or decrease) the amplitude of transistor currents and enlarge memory windows. However, tensile strains only decrease the maximum value of transistor currents and compress memory windows. Mismatch strains were found to have a significant influence on the electrical behaviors of the devices, therefore, they must be considered in FeMFET device designing. (fast track communication)

  9. Pharmacological inhibition of poly(ADP-ribose) polymerase inhibits angiogenesis

    International Nuclear Information System (INIS)

    Rajesh, Mohanraj; Mukhopadhyay, Partha; Batkai, Sandor; Godlewski, Grzegorz; Hasko, Gyoergy; Liaudet, Lucas; Pacher, Pal

    2006-01-01

    Poly(ADP-ribose) polymerase (PARP) is a nuclear enzyme which plays an important role in regulating cell death and cellular responses to DNA repair. Pharmacological inhibitors of PARP are being considered as treatment for cancer both in monotherapy as well as in combination with chemotherapeutic agents and radiation, and were also reported to be protective against untoward effects exerted by certain anticancer drugs. Here we show that pharmacological inhibition of PARP with 3-aminobenzamide or PJ-34 dose-dependently reduces VEGF-induced proliferation, migration, and tube formation of human umbilical vein endothelial cells in vitro. These results suggest that treatment with PARP inhibitors may exert additional benefits in various cancers and retinopathies by decreasing angiogenesis

  10. Control of ATP hydrolysis by ADP bound at the catalytic site of chloroplast ATP synthase as related to protonmotive force and Mg sup 2+

    Energy Technology Data Exchange (ETDEWEB)

    Du, Z.; Boyer, P.D. (Univ. of California, Los Angeles (USA))

    1989-01-24

    The activation of the ATP synthesis and hydrolysis capacity of isolated chloroplast membranes by protonmotive force is known to be associated with the release of tightly bound ADP from the ATP synthase. The data support the view that the activation requires only those structural changes occurring in the steady-state reaction mechanism. The trapping of ADP released during light activation or the chelation of Mg{sup 2+} with EDTA effectively reduces the rate of decay of the ATPase activity. When the release of tightly bound ADP and Mg{sup 2+} is promoted by light activation, followed by immediate dilution and washing to retard the rebinding of the ADP and Mg{sup 2+} released, the ATPase activity remains high in the dark long after the protonmotive force has disappeared. After the addition of ADP and Mg{sup 2+} the decay of the ATPase activity has the same characteristics as those of the unwashed chloroplast membrane. The results are interpreted as indicating that both Mg{sup 2+} and ADP must be present prior to exposure to MgATP for the ATPase to be inhibited. However, in contrast to the isolated chloroplast ATPase, the steady-state activity of the membrane-bound ATPase is not inhibited by excess Mg{sup 2+}. The replacement of ({sup 3}H)ADP from catalytic sites during hydrolysis of unlabeled ATP or during photophosphorylation with unlabeled ADP occurs as anticipated if Mg{sup 2+} and ADP bound at one catalytic site without P{sub i} block catalysis by all three enzyme sites. The inhibited form induced by Mg{sup 2+} and ADP may occur only under laboratory conditions and not have an in vivo role.

  11. NADP/sup +/ enhances cholera and pertussis toxin-catalyzed ADP-ribosylation of membrane proteins

    Energy Technology Data Exchange (ETDEWEB)

    Kawai, Y.; Whitsel, C.; Arinze, I.J.

    1986-05-01

    Cholera or pertussis toxin-catalyzed (/sup 32/P)ADP-ribosylation is frequently used to estimate the concentration of the stimulatory (Ns) or inhibitory (Ni) guanine nucleotide regulatory proteins which modulate the activity of adenylate cyclase. With this assay, however, the degradation of the substrate, NAD/sup +/, by endogenous enzymes such as NAD/sup +/-glycohydrolase (NADase) present in the test membranes can influence the results. In this study the authors show that both cholera and pertussis toxin-catalyzed (/sup 32/P)ADP-ribosylation of liver membrane proteins is markedly enhanced by NADP/sup +/. The effect is concentration dependent; with 20 ..mu..M (/sup 32/P)NAD/sup +/ as substrate maximal enhancement is obtained at 0.5-1.0 mM NADP/sup +/. The enhancement of (/sup 32/P)ADP-ribosylation by NADP/sup +/ was much greater than that by other known effectors such as Mg/sup 2 +/, phosphate or isoniazid. The effect of NADP/sup +/ on ADP-ribosylation may occur by inhibition of the degradation of NAD/sup +/ probably by acting as an alternate substrate for NADase. Among inhibitors tested (NADP/sup +/, isoniazid, imidazole, nicotinamide, L-Arg-methyl-ester and HgCl/sub 2/) to suppress NADase activity, NADP/sup +/ was the most effective and, 10 mM, inhibited activity of the enzyme by about 90%. In membranes which contain substantial activities of NADase the inclusion of NADP/sup +/ in the assay is necessary to obtain maximal ADP-ribosylation.

  12. Internal-strain effect on the valence band of strained silicon and its correlation with the bond angles

    Energy Technology Data Exchange (ETDEWEB)

    Inaoka, Takeshi, E-mail: inaoka@phys.u-ryukyu.ac.jp; Yanagisawa, Susumu; Kadekawa, Yukihiro [Department of Physics and Earth Sciences, Faculty of Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213 (Japan)

    2014-02-14

    By means of the first-principles density-functional theory, we investigate the effect of relative atom displacement in the crystal unit cell, namely, internal strain on the valence-band dispersion of strained silicon, and find close correlation of this effect with variation in the specific bond angles due to internal strain. We consider the [111] ([110]) band dispersion for (111) ((110)) biaxial tensility and [111] ([110]) uniaxial compression, because remarkably small values of hole effective mass m* can be obtained in this dispersion. Under the practical condition of no normal stress, biaxial tensility (uniaxial compression) involves additional normal compression (tensility) and internal strain. With an increase in the internal-strain parameter, the energy separation between the highest and second-highest valence bands becomes strikingly larger, and the highest band with conspicuously small m* extends remarkably down to a lower energy region, until it intersects or becomes admixed with the second band. This is closely correlated with the change in the specific bond angles, and this change can reasonably explain the above enlargement of the band separation.

  13. VERO cells harbor a poly-ADP-ribose belt partnering their epithelial adhesion belt

    Directory of Open Access Journals (Sweden)

    Laura Lafon-Hughes

    2014-10-01

    Full Text Available Poly-ADP-ribose (PAR is a polymer of up to 400 ADP-ribose units synthesized by poly-ADP-ribose-polymerases (PARPs and degraded by poly-ADP-ribose-glycohydrolase (PARG. Nuclear PAR modulates chromatin compaction, affecting nuclear functions (gene expression, DNA repair. Diverse defined PARP cytoplasmic allocation patterns contrast with the yet still imprecise PAR distribution and still unclear functions. Based on previous evidence from other models, we hypothesized that PAR could be present in epithelial cells where cadherin-based adherens junctions are linked with the actin cytoskeleton (constituting the adhesion belt. In the present work, we have examined through immunofluorescence and confocal microscopy, the subcellular localization of PAR in an epithelial monkey kidney cell line (VERO. PAR was distinguished colocalizing with actin and vinculin in the epithelial belt, a location that has not been previously reported. Actin filaments disruption with cytochalasin D was paralleled by PAR belt disruption. Conversely, PARP inhibitors 3-aminobenzamide, PJ34 or XAV 939, affected PAR belt synthesis, actin distribution, cell shape and adhesion. Extracellular calcium chelation displayed similar effects. Our results demonstrate the existence of PAR in a novel subcellular localization. An initial interpretation of all the available evidence points towards TNKS-1 as the most probable PAR belt architect, although TNKS-2 involvement cannot be discarded. Forthcoming research will test this hypothesis as well as explore the existence of the PAR belt in other epithelial cells and deepen into its functional implications.

  14. Strain-induced Pockels effect in silicon waveguides (Conference Presentation)

    Science.gov (United States)

    Berciano, Mathias; Damas, Pedro; Marcaud, Guillaume; Le Roux, Xavier; Crozat, Paul; Alonso-Ramos, Carlos; Benedikovic, Daniel; Marris-Morini, Delphine; Cassan, Eric; Vivien, Laurent

    2017-05-01

    With the increasing demand of data, current chip-scale communication systems based on metallic interconnects suffer rate limitations and power consumptions. In this context, Silicon photonics has emerged as an alternative by replacing the classical copper interconnects with silicon waveguides while taking advantage of the well-established CMOS foundries techniques to reduce fabrication costs. Silicon is now considered as an excellent candidate for the development of integrated optical functionalities including waveguiding structures, modulators, switches… One of the main challenges of silicon photonics is to reduce the power consumption and the swing voltage of optical silicon modulators while increasing the data rate speed. However, silicon is a centrosymmetric crystal, vanishing the second order nonlinear effect i.e. Pockels effect which is intrinsically a high speed effect. To overcome this limitation, mechanical stresses on silicon to break the crystal symmetry can be used depositing a strained overlayer. In this work, we have studied the effect of the stress layer in the modulation characteristics based on Mach-Zehnder interferometers. The deposition of silicon nitride as the stress layer and its optimization to induce the maximum effect will be presented.

  15. The allosteric transition of GroEL induced by metal fluoride-ADP complexes.

    Science.gov (United States)

    Inobe, Tomonao; Kikushima, Kenji; Makio, Tadashi; Arai, Munehito; Kuwajima, Kunihiro

    2003-05-23

    To understand the mechanism of a functionally important ATP-induced allosteric transition of GroEL, we have studied the effect of a series of metal fluoride-ADP complexes and vanadate-ADP on GroEL by kinetic fluorescence measurement of pyrene-labeled GroEL and by small-angle X-ray scattering measurement of wild-type GroEL. The metal fluorides and vanadate, complexed with ADP, are known to mimic the gamma-phosphate group of ATP, but they differ in geometry and size; it is expected that these compounds will be useful for investigating the strikingly high specificity of GroEL for ATP that enables the induction of the allosteric transition. The kinetic fluorescence measurement revealed that aluminium, beryllium, and gallium ions, when complexed with the fluoride ion and ADP, induced a biphasic fluorescence change of pyrenyl GroEL, while scandium and vanadate ions did not induce any kinetically observed change in fluorescence. The burst phase and the first phase of the fluorescence kinetics were reversible, while the second phase and subsequent changes were irreversible. The dependence of the burst-phase and the first-phase fluorescence changes on the ADP concentration indicated that the burst phase represents non-cooperative nucleotide binding to GroEL, and that the first phase represents the allosteric transition of GroEL. Both the amplitude and the rate constant of the first phase of the fluorescence kinetics were well understood in terms of a kinetic allosteric model, which is a combination of transition state theory and the Monod-Wyman-Changeux allosteric model. From the kinetic allosteric model analysis, the relative free energy of the transition state in the metal fluoride-ADP-induced allosteric transition of GroEL was found to be larger than the corresponding free energy of the ATP-induced allosteric transition by more than 5.5kcal/mol. However, the X-ray scattering measurements indicated that the allosteric state induced by these metal fluoride-ADP complexes is

  16. X-ray determination of crystallite size and effect of lattice strain on ...

    Indian Academy of Sciences (India)

    ... the half-widths and integrated intensities of the Bragg reflections. In Pt, the Debye–Waller factor is found to increase with lattice strain. From the correlation between the strain and effective Debye–Waller factor, the Debye–Waller factors for zero strain have been estimated for Pt. The variation of energy of vacancy formation ...

  17. Annealing effects on strain and stress sensitivity of polymer optical fibre based sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A. F.; Zubel, M. G.

    2016-01-01

    The annealing effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors after their photoinscription are investigated. PMMA optical fibre based Bragg grating sensors are first photo-inscribed and then they were placed into hot water for annealing. Strain, stress...... fibre tends to increase the strain, stress and force sensitivity of the photo-inscribed sensor....

  18. Plasma kallikrein enhances platelet aggregation response by subthreshold doses of ADP.

    Science.gov (United States)

    Ottaiano, Tatiana F; Andrade, Sheila S; de Oliveira, Cleide; Silva, Mariana C C; Buri, Marcus V; Juliano, Maria A; Girão, Manoel J B C; Sampaio, Misako U; Schmaier, Alvin H; Wlodawer, Alexander; Maffei, Francisco H A; Oliva, Maria Luiza V

    2017-04-01

    Human plasma kallikrein (huPK) potentiates platelet responses to subthreshold doses of ADP, although huPK itself, does not induce platelet aggregation. In the present investigation, we observe that huPK pretreatment of platelets potentiates ADP-induced platelet activation by prior proteolysis of the G-protein-coupled receptor PAR-1. The potentiation of ADP-induced platelet activation by huPK is mediated by the integrin α IIb β 3 through interactions with the KGD/KGE sequence motif in huPK. Integrin α IIb β 3 is a cofactor for huPK binding to platelets to support PAR-1 hydrolysis that contributes to activation of the ADP signaling pathway. This activation pathway leads to phosphorylation of Src, AktS 473 , ERK1/2, and p38 MAPK, and to Ca 2+ release. The effect of huPK is blocked by specific antagonists of PAR-1 (SCH 19197) and α IIb β 3 (abciximab) and by synthetic peptides comprising the KGD and KGE sequence motifs of huPK. Further, recombinant plasma kallikrein inhibitor, rBbKI, also blocks this entire mechanism. These results suggest a new function for huPK. Formation of plasma kallikrein lowers the threshold for ADP-induced platelet activation. The present observations are consistent with the notion that plasma kallikrein promotes vascular disease and thrombosis in the intravascular compartment and its inhibition may ameliorate cardiovascular disease and thrombosis. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  19. Biaxial load effects on the crack border elastic strain energy and strain energy rate

    Science.gov (United States)

    Eftis, J.; Subramonian, N.; Liebowitz, H.

    1977-01-01

    The validity of the singular solution (first term of a series representation) is investigated for the crack tip stress and displacement field in an infinite sheet with a flat line crack with biaxial loads applied to the outer boundaries. It is shown that if one retains the second contribution to the series approximations for stress and displacement in the calculation of the local elastic strain energy density and elastic strain energy rate in the crack border region, both these quantities have significant biaxial load dependency. The value of the J-integral does not depend on the presence of the second term of the series expansion for stress and displacement. Thus J(I) is insensitive to the presence of loads applied parallel to the plane of the crack.

  20. Poly(ADP-ribose) polymerase, a potential target for drugs: Cellular regulatory role of the polymer and the polymerase protein mediated by catalytic and macromolecular colligative actions (Review).

    Science.gov (United States)

    Kun

    1998-08-01

    The cellular coenzymatic role of NAD, being a pleiotropic cofactor for diverse cellular reactions, is extended to poly(ADP-ribose) and to the highly abundant nuclear protein, poly(ADP-ribose) polymerase, with special focus on the pharmacological action of ligands on the latter. The polymer is defined to possess a helical configuration. From direct analyses of the polymer under physiological conditions, it is concluded that the polymerase is dormant in normal tissues, but is activated under certain pathological conditions: malignancy, retroviral integrate containing cells, and in a variety of inflammatory states. The interaction of poly(ADP-ribose) polymerase ligands with the DNA component of the active poly (ADP-ribose) polymerase - DNA complex is shown. A major cellular function of the poly(ADP-ribose) polymerase protein is its binding capacity to a large number of nuclear proteins and DNA sites, an effect which is induced by drugs that inhibit the polymerase activity. The malignancy-reverting effect of poly(ADP-ribose) polymerase ligand drugs is illustrated in chemically and oncovirally transformed cancer cells. The poly(ADP-ribose) polymerase ligand-induced cessation of HIV replication is analyzed. Peroxynitrite-induced DNA damage-initiated pathological responses are shown to be inhibited by a specific poly(ADP-ribose) polymerase ligand. The irreversibly acting C-NO drugs oxidize asymmetric zinc fingers [poly(ADP-ribose) polymerase, HIV gag-precursor protein] and act as anti-cancer and anti-HIV agents, an effect that is regulated by cellular concentration of GSH.

  1. Effect of biosurfactant from two strains of Pseudomonas on ...

    African Journals Online (AJOL)

    Two Pseudomonas strains isolated from oil-contaminated soil which produce biosurfactant were studied. The biosurfactant containing broth formed stable emulsions with liquid light paraffin, cooking medium vegetable oil and toluene. The strains under study produce extra cellular biosurfactant in the culture media.

  2. Inoculation effects of two South African cyanobacteria strains on ...

    African Journals Online (AJOL)

    Two South African cyanobacteria strains (coded 3g and 7e) of the genus Nostoc were evaluated for improvement of the aggregate stability of a silty loam soil with low organic C content and compared with Nostoc strain 9v isolated from a Tanzanian soil. The soil was either cropped with maize or non-cropped and inoculated ...

  3. Effect of strain field on displacement cascade in tungsten studied by molecular dynamics simulation

    Energy Technology Data Exchange (ETDEWEB)

    Wang, D. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Gao, N., E-mail: ning.gao@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Wang, Z.G., E-mail: zhgwang@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); Gao, X. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); He, W.H. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Cui, M.H.; Pang, L.L.; Zhu, Y.B. [Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 730000 (China)

    2016-10-01

    Using atomistic methods, the coupling effect of strain field and displacement cascade in body-centered cubic (BCC) tungsten is directly simulated by molecular dynamics (MD) simulations at different temperatures. The values of the hydrostatic and uniaxial (parallel or perpendicular to primary knock-on atom (PKA) direction) strains are from −2% to 2% and the temperature is from 100 to 1000 K. Because of the annealing effect, the influence of strain on radiation damage at low temperature has been proved to be more significant than that at high temperature. When the cascade proceeds under the hydrostatic strain, the Frenkel Pair (FP) production, the fraction of defect in cluster and the average size of the defect cluster, all increase at tensile state and decrease at compressive state. When the cascade is under uniaxial strain, the effect of strain parallel to PKA direction is less than the effect of hydrostatic strain, while the effect of strain perpendicular to PKA direction can be negligible. Under the uniaxial strain along 〈1 1 1〉 direction, the SIA and SIA cluster is observed to orientate along the strain direction at tensile state and the uniaxial compressive strain with direction perpendicular to 〈1 1 1〉 has led to the similar preferred nucleation. All these results indicate that under irradiation, the tensile state should be avoided for materials used in nuclear power plants.

  4. Effect of plastic strain on elastic-plastic fracture toughness of SM490 carbon steel

    International Nuclear Information System (INIS)

    Kamaya, Masayuki

    2010-01-01

    Although the plastic strain induced in materials increases the mechanical strength, it may reduce the fracture toughness. The change in the fracture toughness is brought about by four factors; reduction in critical plastic strain due to pre-strain, localization of deformation, increase of material strength by work hardening, and change in material resistance for fracture. In this study, correlation between change in fracture toughness by pre-strain and the four factors was investigated. Firstly, the change in the tensile properties and fracture toughness were examined for pre-strained SM490 carbon steel. The specimens with blunt notch of 0.2 mm and 0.4 mm radius were used in addition to those with conventional fatigue pre-cracking. The degree of applied plastic strain was 5%, 10% and 20%. The fracture toughness was largest when the induced plastic strain was 5%, although it decreased in the cases for the plastic strain of 10% and 20%. Secondly, the stress and strain field near notch tip was evaluated by simulating the experiment using elastic-plastic finite element analyses. It was concluded that the change in fracture toughness was mainly brought about by the change in material resistance caused by the plastic strain. Under the plastic strain of 10% and 20%, the critical plastic strain for crack initiation decreased due to change in material resistance in addition to apparent reduction by pre-straining. The localized deformation and work hardening had minor effect on the change in fracture toughness. (author)

  5. Loss of the Mono-ADP-ribosyltransferase, Tiparp, Increases Sensitivity to Dioxin-induced Steatohepatitis and Lethality*

    Science.gov (United States)

    Ahmed, Shaimaa; Bott, Debbie; Gomez, Alvin; Tamblyn, Laura; Rasheed, Adil; Cho, Tiffany; MacPherson, Laura; Sugamori, Kim S.; Yang, Yang; Grant, Denis M.; Cummins, Carolyn L.; Matthews, Jason

    2015-01-01

    The aryl hydrocarbon receptor (AHR) mediates the toxic effects of the environmental contaminant dioxin (2,3,7,8-tetrachlorodibenzo-p-dioxin; TCDD). Dioxin causes a range of toxic responses, including hepatic damage, steatohepatitis, and a lethal wasting syndrome; however, the mechanisms are still unknown. Here, we show that the loss of TCDD-inducible poly(ADP-ribose) polymerase (Tiparp), an ADP-ribosyltransferase and AHR repressor, increases sensitivity to dioxin-induced toxicity, steatohepatitis, and lethality. Tiparp−/− mice given a single injection of 100 μg/kg dioxin did not survive beyond day 5; all Tiparp+/+ mice survived the 30-day treatment. Dioxin-treated Tiparp−/− mice exhibited increased liver steatosis and hepatotoxicity. Tiparp ADP-ribosylated AHR but not its dimerization partner, the AHR nuclear translocator, and the repressive effects of TIPARP on AHR were reversed by the macrodomain containing mono-ADP-ribosylase MACROD1 but not MACROD2. These results reveal previously unidentified roles for Tiparp, MacroD1, and ADP-ribosylation in AHR-mediated steatohepatitis and lethality in response to dioxin. PMID:25975270

  6. Role of poly(ADP-ribosepolymerase 2 in DNA repair

    Directory of Open Access Journals (Sweden)

    Lavrik O. I.

    2012-06-01

    Full Text Available Poly(ADP-ribosylation is a posttranslational protein modification significant for the genomic stability and cell survival in response to DNA damage. Poly(ADP-ribosylation is catalyzed by poly(ADP-ribosepolymerases (PARPs, which use NAD+ as a substrate, synthesize polymer of (ADP-ribose (PAR covalently attached to nuclear proteins including PARP themselves. PARPs constitute a large family of proteins, in which PARP1 is the most abundant and best-characterized member. In spite of growing body of PARPs’ role in cellular processes, PARP2, the closest homolog of PARP1, still remains poorly characterized at the level of its contribution to different pathways of DNA repair. An overview summarizes in vivo and in vitro data on PARP2 implication in specialized DNA repair processes, base excision repair and double strand break repair.

  7. Strain rate effect on the thermomechanical behavior of a thermoset shape memory polymer

    Science.gov (United States)

    Wang, Anqi; Li, Guoqiang; Meng, Harper

    2013-08-01

    Driven by conformational entropy, a shape memory polymer (SMP) is capable of memorizing typical programming information, such as level of induced strain, deformation sequence and temperature profile. Because strain rate is one of the variables during programming, it is desirable to know whether the strain rate effect can be memorized or not. In this study, the effects of programming strain rate on the thermomechanical behavior of a thermoset SMP were investigated. A polystyrene based thermoset SMP was programmed under various strain rates (1500, 0.1 and 0.0001 s-1) in the glassy state, with the same prestrain level and temperature profiles. The thermomechanical response and some crucial physical properties were investigated via multiple characterization techniques. The test results indicate that programming strain rate has an influence on the glass transition temperature. A higher strain rate consistently leads to higher relaxation of prestrain and thus lower strain fixity. Moreover, the recovery strain and recovery strain rate rely on the pseudo-plastic strain during programming, which is associated with the programming strain rate.

  8. Intracellular Mono-ADP-Ribosylation in Signaling and Disease

    Science.gov (United States)

    Bütepage, Mareike; Eckei, Laura; Verheugd, Patricia; Lüscher, Bernhard

    2015-01-01

    A key process in the regulation of protein activities and thus cellular signaling pathways is the modification of proteins by post-translational mechanisms. Knowledge about the enzymes (writers and erasers) that attach and remove post-translational modifications, the targets that are modified and the functional consequences elicited by specific modifications, is crucial for understanding cell biological processes. Moreover detailed knowledge about these mechanisms and pathways helps to elucidate the molecular causes of various diseases and in defining potential targets for therapeutic approaches. Intracellular adenosine diphosphate (ADP)-ribosylation refers to the nicotinamide adenine dinucleotide (NAD+)-dependent modification of proteins with ADP-ribose and is catalyzed by enzymes of the ARTD (ADP-ribosyltransferase diphtheria toxin like, also known as PARP) family as well as some members of the Sirtuin family. Poly-ADP-ribosylation is relatively well understood with inhibitors being used as anti-cancer agents. However, the majority of ARTD enzymes and the ADP-ribosylating Sirtuins are restricted to catalyzing mono-ADP-ribosylation. Although writers, readers and erasers of intracellular mono-ADP-ribosylation have been identified only recently, it is becoming more and more evident that this reversible post-translational modification is capable of modulating key intracellular processes and signaling pathways. These include signal transduction mechanisms, stress pathways associated with the endoplasmic reticulum and stress granules, and chromatin-associated processes such as transcription and DNA repair. We hypothesize that mono-ADP-ribosylation controls, through these different pathways, the development of cancer and infectious diseases. PMID:26426055

  9. The Role of Platelet-Derived ADP and ATP in Promoting Pancreatic Cancer Cell Survival and Gemcitabine Resistance

    Directory of Open Access Journals (Sweden)

    Omar Elaskalani

    2017-10-01

    Full Text Available Platelets have been demonstrated to be vital in cancer epithelial-mesenchymal transition (EMT, an important step in metastasis. Markers of EMT are associated with chemotherapy resistance. However, the association between the development of chemoresistance, EMT, and the contribution of platelets to the process, is still unclear. Here we report that platelets regulate the expression of (1 human equilibrative nucleoside transporter 1 (hENT1 and (2 cytidine deaminase (CDD, markers of gemcitabine resistance in pancreatic cancer. Human ENT1 (hENT1 is known to enable cellular uptake of gemcitabine while CDD deactivates gemcitabine. Knockdown experiments demonstrate that Slug, a mesenchymal transcriptional factor known to be upregulated during EMT, regulates the expression of hENT1 and CDD. Furthermore, we demonstrate that platelet-derived ADP and ATP regulate Slug and CDD expression in pancreatic cancer cells. Finally, we demonstrate that pancreatic cancer cells express the purinergic receptor P2Y12, an ADP receptor found mainly on platelets. Thus ticagrelor, a P2Y12 inhibitor, was used to examine the potential therapeutic effect of an ADP receptor antagonist on cancer cells. Our data indicate that ticagrelor negated the survival signals initiated in cancer cells by platelet-derived ADP and ATP. In conclusion, our results demonstrate a novel role of platelets in modulating chemoresistance in pancreatic cancer. Moreover, we propose ADP/ATP receptors as additional potential drug targets for treatment of pancreatic cancer.

  10. An incremental flow theory for crystal plasticity incorporating strain gradient effects

    DEFF Research Database (Denmark)

    Nellemann, Christopher; Niordson, Christian Frithiof; Nielsen, Kim Lau

    2017-01-01

    a gradient enhanced effective slip measure governs hardening evolution. The effect of both plastic strains and plastic strain gradients are combined into this scalar effective slip quantity, the energy associated with plastic strain is dissipative (unrecoverable), while the energy from plastic strain...... gradients is recoverable (free). The framework developed forms the basis of a finite element implementation and is demonstrated on benchmark problems designed to bring out effects such as strengthening and hardening. Monotonic loading and plane strain deformation is assumed throughout, but despite this, non......-proportional straining is predicted in the plastic regime even under pure shear conditions. Results of single slip and symmetric double slip reveal that strengthening and hardening are governed by the slip system orientation and the material length parameter only....

  11. The Effect of Grain Size on the Strain Hardening Behavior for Extruded ZK61 Magnesium Alloy

    Science.gov (United States)

    Zhang, Lixin; Zhang, Wencong; Chen, Wenzhen; Duan, Junpeng; Wang, Wenke; Wang, Erde

    2017-12-01

    The effects of grain size on the tensile and compressive strain hardening behaviors for extruded ZK61 alloys have been investigated by uniaxial tensile and compressive tests along the extrusion directions. Cylindrical tension and compression specimens of extruded ZK61 alloys with various sized grain were fabricated by annealing treatments. Tensile and compressive tests at ambient temperature were conducted at a strain rate of 0.5 × 10-3 s-1. The results indicate that both tensile strain hardening and compressive strain hardening of ZK61 alloys with different grain sizes have an athermal regime of dislocation accumulation in early deformation. The threshold stress value caused dynamic recovery is predominantly related to grain size in tensile strain hardening, but the threshold stress values for different grain sizes are almost identical in compressive strain hardening. There are obvious transition points on the tensile strain hardening curves which indicate the occurrence of dynamic recrystallization (DRX). The tensile strain hardening rate of the coarse-grained alloy obviously decreases faster than that of fine-grained alloys before DRX and the tensile strain hardening curves of different grain sizes basically tend to parallel after DRX. The compressive strain hardening rate of the fine-grained alloy obviously increases faster than that of coarse-grained alloy for twin-induced strain hardening, but compressive strain hardening curves also tend to parallel after twinning is exhausted.

  12. The effect of strain rate on the viscoplastic behavior of isotactic polypropylene at finite strains

    DEFF Research Database (Denmark)

    Drozdov, Aleksey D.; Christiansen, Jesper de Claville

    2002-01-01

    is thought of as an ensemble of meso-regions connected with each other by links (lamellar blocks). In the sub-yield region of deformations, junctions between chains in meso-domains slide with respect to their reference positions (which reflects sliding of nodes in the amorphous phase and fine slip...... prior to testing. A constitutive model is developed for the viscoplastic behavior of isotactic polypropylene at finite strains. A semicrystalline polymer is treated as equivalent heterogeneous network of chains bridged by permanent junctions (physical cross-links and entanglements). The network...... of lamellar blocks). Above the yield point, the sliding process is accompanied by displacements of meso-domains in the ensemble with respect to each other (which reflects coarse slip and fragmentation of lamellar blocks). To account for alignment of disintegrated lamellar blocks along the direction of maximal...

  13. 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.

  14. Analysis of local deformation effects in resistive strain sensing of a submicron-thickness AFM cantilever

    Science.gov (United States)

    Adams, Jonathan D.; Schwalb, Christian H.; Winhold, Marcel; Šńukić, Maja; Huth, Michael; Fantner, Georg E.

    2013-05-01

    Incorporating resistive strain-sensing elements into MEMS devices is a long-standing approach for electronic detection of the device deformation. As the need for more sensitivity trends the device dimensions downwards, the size of the strain-sensor may become comparable to the device size, which can have significant impact on the mechanical behaviour of the device. To study this effect, we modelled a submicron-thickness silicon nitride AFM cantilever with strain-sensing element. Using finite element analysis, we calculated the strain in the sensor elements for a deflected cantilever. The sensor element contributes to a local stiffening effect in the device structure which lowers the strain in the sensor. By varying the sensor geometry, we investigated the degree to which this effect impacts the strain. Minimizing the sensor size increases the strain, but the reduction in sensor cross-sectional area increases the resistance and expected sensor noise. The optimal sensor geometry must therefore account for this effect. We used our analysis to optimize geometric variations of nanogranular tunnelling resistor (NTR) strain sensors arranged in a Wheatstone bridge on a silicon nitride AFM cantilever. We varied the dimensions of each sensor element to maintain a constant cross-sectional area but maximize the strain in the sensor element. Through this approach, we expect a 45% increase in strain in the sensor and corresponding 20% increase in the Wheatstone bridge signal. Our results provide an important consideration in the design geometry of resistive strainsensing elements in MEMS devices.

  15. Inverse strain rate effect on cyclic stress response in annealed Zircaloy-2

    Energy Technology Data Exchange (ETDEWEB)

    Sudhakar Rao, G.; Verma, Preeti [Center of Advanced Study, Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Chakravartty, J.K. [Mechanical Metallurgy Group, Bhabha Atomic Research Center, Trombay 400 085, Mumbai (India); Nudurupati, Saibaba [Nuclear Fuel Complex, Hyderabad 500 062 (India); Mahobia, G.S.; Santhi Srinivas, N.C. [Center of Advanced Study, Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India); Singh, Vakil, E-mail: vsingh.met@itbhu.ac.in [Center of Advanced Study, Department of Metallurgical Engineering, Indian Institute of Technology (Banaras Hindu University), Varanasi 221005 (India)

    2015-02-15

    Low cycle fatigue behavior of annealed Zircaloy-2 was investigated at 300 and 400 °C at different strain amplitudes and strain rates of 10{sup −2}, 10{sup −3}, and 10{sup −4} s{sup −1}. Cyclic stress response showed initial hardening with decreasing rate of hardening, followed by linear cyclic hardening and finally secondary hardening with increasing rate of hardening for low strain amplitudes at both the temperatures. The rate as well the degree of linear hardening and secondary hardening decreased with decrease in strain rate at 300 °C, however, there was inverse effect of strain rate on cyclic stress response at 400 °C and cyclic stress was increased with decrease in strain rate. The fatigue life decreased with decrease in strain rate at both the temperatures. The occurrence of linear cyclic hardening, inverse effect of strain rate on cyclic stress response and deterioration in fatigue life with decrease in strain rate may be attributed to dynamic strain aging phenomena resulting from enhanced interaction of dislocations with solutes. Fracture surfaces revealed distinct striations, secondary cracking, and oxidation with decrease in strain rate. Deformation substructure showed parallel dislocation lines and dislocation band structure at 300 °C. Persistent slip band wall structure and development of fine Corduroy structure was observed at 400 °C.

  16. Effects of genome duplication on phenotypes and industrial applications of Saccharomyces cerevisiae strains.

    Science.gov (United States)

    Zhang, Ke; Fang, Ya-Hong; Gao, Ke-Hui; Sui, Yang; Zheng, Dao-Qiong; Wu, Xue-Chang

    2017-07-01

    Polyploidy is common in Saccharomyces cerevisiae strains, but the physiological and phenotypic effects of ploidy changes have not been fully clarified. Here, isogenic diploid, triploid, and tetraploid S. cerevisiae strains were constructed from a haploid strain, CEN.PK2-1C. Stress tolerance and ethanol fermentation performance of the four euploid strains were compared. Each euploid strain had strengths and weaknesses in tolerance to certain stressors, and no single strain was tolerant of all stressors. The diploid had higher ethanol production than the other strains in normal fermentation medium, while the triploid strain showed the fastest fermentation rate in the presence of inhibitors found in lignocellulosic hydrolysate. Physiological determination revealed diverse physiological attributes, such as trehalose, ergosterol, glutathione, and anti-oxidative enzymes among the strains. Our analyses suggest that both ploidy parity and number of chromosome sets contribute to changes in physiological status. Using qRT-PCR, different expression patterns of genes involved in the regulation of cell morphology and the biosynthesis of key physiological attributes among strains were determined. Our data provide novel insights into the multiple effects of genome duplication on yeast cells and are a useful reference for breeding excellent strains used in specific industrial applications.

  17. A study of the effect of apparent strain on thermal stress measurement for two types of elevated temperature strain gages

    Science.gov (United States)

    Jenkins, J. M.

    1983-01-01

    A weldable type strain gage was used to measure low level thermal stress in an elevated temperature environment. Foil strain gages used in a comparative manner reveal that the apparent strain of weldable strain gages is not sufficiently known to acquire accurate low level thermal stress data. Apparent strain data acquired from coupon tests reveals a large scatter in apparent strain characteristics among the weldable strain gages. It is concluded that apparent strain data for individual weldable strain gages must be required prior to installation if valid thermal stress data is to be obtained through the temperature range of room temperature to 755 K (900 F).

  18. Effect of composite type and placement technique on cuspal strain.

    Science.gov (United States)

    Ólafsson, Vilhelm G; Ritter, André V; Swift, Edward J; Boushell, Lee W; Ko, Ching-Chang; Jackson, Gabrielle R; Ahmed, Sumitha N; Donovan, Terence E

    2018-01-01

    To compare the cuspal strain in Class II restorations made with bulk-fill and conventional composite resins. Fifty extracted maxillary premolars were mounted into phenolic rings and divided into five groups (n = 10). Specimens received standardized MOD preparations. A two-step self-etch adhesive was applied and the preparations were restored using a custom matrix as follows: Filtek Supreme Ultra in eight 2-mm increments (FSUI); Filtek Supreme Ultra in bulk (FSUB); SonicFill in bulk (SF); SureFil SDR flow in bulk, covered with a 2-mm occlusal layer of Filtek Supreme Ultra (SDR/FSU); Tetric EvoCeram Bulk Fill in bulk (TEBF). Strain gages bonded to the buccal and lingual cusps recorded cuspal strain during restorations. End strain values were determined and data were subjected to Kruskal-Wallis testing, followed by one-way ANOVA and Tukey´s post hoc test. Combined strain values and standard deviations (in µɛ) were: FSUI: 723 ± 102.8, FSUB: 929.2 ± 571.9, SF: 519.1 ± 80.2, SDR-FSU: 497.4 ± 67.6 and TEBF: 604.5 ± 127.1. A significant difference was found between group FSUI and groups SF, SDR-FSU, and TEBF. Group FSUB showed significantly higher mean strain and greater standard deviation than all other groups due to cuspal fractures, and was thus excluded from the statistical analysis. The tested bulk-fill composite resins exerted less strain onto tooth structure than the incrementally placed conventional composite resin, although the magnitude of generated strain was product-dependent. Bulk-filling with conventional composite resins is contraindicated. Bulk-fill composite resins exerted less strain onto adjacent tooth structure than a traditional composite, even when that composite is was placed incrementally. Bulk-filling with traditional composite resins is unpredictable and contraindicated. © 2017 Wiley Periodicals, Inc.

  19. Effect of CuO Nanoparticles over Isolated Bacterial Strains from Agricultural Soil

    International Nuclear Information System (INIS)

    Concha-Guerrero, S.I.; Pinon-Castillo, H.A.; Luna-Velasco, A.; Orrantia-Borunda, E.; Brito, E.M.S.; Tarango-Rivero, S.H.; Caretta, C.A.; Duran, R.

    2014-01-01

    The increased use of the nanoparticles (NPs) on several processes is notorious. In contrast the eco toxicological effects of NPs have been scarcely studied. The main current researches are related to the oxide metallic NPs. In the present work, fifty-six bacterial strains were isolated from soil, comprising 17 different OTUs distributed into 3 classes: Bacilli (36 strains), Flavobacteria (2 strains), and Gamma proteobacteria (18 strains). Copper oxide nanoparticles (CuONPs) were synthesized using a process of chemical precipitation. The obtained CuONPs have a spherical shape and primary size less than 17 nm. Twenty-one strains were used to evaluate the cytotoxicity of CuONPs and 11 of these strains showed high sensibility. Among those 11 strains, 4 (Brevibacillus later osporus strain CSS8, Chryseobacterium indoltheticum strain CSA28, and Pantoea ananatis strains CSA34 and CSA35) were selected to determine the kind of damage produced. The CuONPs toxic effect was observed at expositions over 25 mg·L -1 and the damage to cell membrane above 160 mg·L -1 . The electron microscopy showed the formation of cavities, holes, membrane degradation, blebs, cellular collapse, and lysis. These toxic effects may probably be due to the ions interaction, the oxide-reduction reactions, and the generation of reactive species

  20. Reversible axial-strain effect in Y-Ba-Cu-O coated conductors

    Energy Technology Data Exchange (ETDEWEB)

    Cheggour, N [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Ekin, J W [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Thieme, C L H [American Superconductor Corporation, Westborough, MA 01581 (United States); Xie, Y-Y [SuperPower Incorporated, Schenectady, NY 12304 (United States); Selvamanickam, V [SuperPower Incorporated, Schenectady, NY 12304 (United States); Feenstra, R [Oak Ridge National Laboratory, Oak Ridge, TN 37831 (United States)

    2005-12-15

    The recently discovered reversible strain effect in Y-Ba-Cu-O (YBCO) coated conductors contrasts with the general understanding that the effect of strain on the critical-current density J{sub c} in practical high-temperature superconductors is determined only by crack formation in the ceramic component. Instead of having a constant J{sub c} as a function of strain before an irreversible drop when cracks form in the superconductor, J{sub c} in YBCO coated conductors can decrease or increase reversibly with strain over a significant strain range up to an irreversible strain limit. This reversible effect is present in samples fabricated either with rolling-assisted biaxially textured Ni-W substrates or with ion-beam-assisted deposition on Hastalloy substrates. The reversibility of J{sub c} with strain is observed for thin as well as thick YBCO films, and at two very different temperatures (76 and 4 K). The reversible effect is dependent on temperature and magnetic field, thus indicating its intrinsic nature. We also report an enhancement of the irreversible strain limit {epsilon}{sub irr} where the reversible strain effect ends and YBCO cracking starts. The value of {epsilon}{sub irr} increases from about 0.4% to more than 0.5% when YBCO coated conductors are fabricated with an additional Cu protection layer.

  1. Reversible axial-strain effect in Y-Ba-Cu-O coated conductors

    International Nuclear Information System (INIS)

    Cheggour, N; Ekin, J W; Thieme, C L H; Xie, Y-Y; Selvamanickam, V; Feenstra, R

    2005-01-01

    The recently discovered reversible strain effect in Y-Ba-Cu-O (YBCO) coated conductors contrasts with the general understanding that the effect of strain on the critical-current density J c in practical high-temperature superconductors is determined only by crack formation in the ceramic component. Instead of having a constant J c as a function of strain before an irreversible drop when cracks form in the superconductor, J c in YBCO coated conductors can decrease or increase reversibly with strain over a significant strain range up to an irreversible strain limit. This reversible effect is present in samples fabricated either with rolling-assisted biaxially textured Ni-W substrates or with ion-beam-assisted deposition on Hastalloy substrates. The reversibility of J c with strain is observed for thin as well as thick YBCO films, and at two very different temperatures (76 and 4 K). The reversible effect is dependent on temperature and magnetic field, thus indicating its intrinsic nature. We also report an enhancement of the irreversible strain limit ε irr where the reversible strain effect ends and YBCO cracking starts. The value of ε irr increases from about 0.4% to more than 0.5% when YBCO coated conductors are fabricated with an additional Cu protection layer

  2. The effect of five probiotic lactobacilli strains on the growth and biofilm formation of Streptococcus mutans.

    Science.gov (United States)

    Lin, X; Chen, X; Chen, Y; Jiang, W; Chen, H

    2015-01-01

    To compare the effects of five probiotic lactobacilli strains on the growth and biofilm formation of Streptococcus mutans (MS). Five probiotic lactobacilli bacteria (LB), Lactobacillus casei Shirota, Lactobacillus casei LC01, Lactobacillus plantarum ST-III, Lactobacillus paracasei Lpc-37, and Lactobacillus rhamnosus HN001, were used as test strains effecting on the Streptococci strain S. mutans UA159 in this study. The effect of LB strains and their supernatants on the viability of the MS was evaluated. Then, the effect of LB strains on the growth of MS biofilm formation was observed by fluorescence microscope. All of the LB strains inhibited the growth of MS at concentrations of 1 × 10(8) and 3 × 10(8) CFU ml(-1) (P strains inhibited the growth of MS (P strains inhibited the growth and biofilm formation of MS, likely through the production of an acid environment, bacteriocin-like poly peptides, or both, and the effects on MS were dependent on the LB strains used. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  3. Actions of ADP, but not ATP, on cytosolic free Ca2+ in single rat hepatocytes mimicked by 2-methylthioATP.

    OpenAIRE

    Dixon, C. J.; Cobbold, P. H.; Green, A. K.

    1995-01-01

    1. Aequorin-injected, single rat hepatocytes generate series of repetitive transients in cytosolic free calcium concentration ([Ca2+]i) when stimulated with agonists acting through the phosphoinositide signalling pathway, including ADP and ATP. We have previously described differences in the [Ca2+]i responses of aequorin-injected hepatocytes to ADP and ATP. 2. The effects of the phosphorothioate analogue of ATP, 2-methylthioATP (2-meSATP), have been examined on single rat hepatocytes. This an...

  4. The effect of target strain error on plantar tissue stress.

    Science.gov (United States)

    Pai, Shruti; Ledoux, William R

    2010-07-01

    Accurate quantification of soft tissue properties, specifically the stress relaxation behavior of viscoelastic tissues such as plantar tissue, requires precise testing under physiologically relevant loading. However, limitations of testing equipment often result in target strain errors that can contribute to large stress errors and confound comparative results to an unknown extent. Previous investigations have modeled this artifact, but they have been unable to obtain empirical data to validate their models. Moreover, there are no studies that address this issue for plantar tissue. The purpose of this research was to directly measure the difference in peak force for a series of small target strain errors within the range of our typical stress relaxation experiments for the subcutaneous plantar soft tissue. Five plantar tissue specimens were tested to seven incremental target strain error levels of -0.9%, -0.6%, -0.3%, 0.0%, 0.3%, 0.6%, and 0.9%, so as to undershoot and overshoot the target displacement in 0.3% increments. The imposed strain errors were accurately attained using a special compensation feature of our materials testing software that can drive the actuator to within 0% (1-2 microm) of the target level for cyclic tests. Since stress relaxation tests are not cyclic, we emulated the ramp portion of our stress relaxation tests with 5 Hz triangle waves. The average total stress variation for all specimens was 25+/-5%, with the highest and lowest stresses corresponding to the largest and smallest strain errors of 0.9% and -0.9%, respectively. A strain overshoot of 0.3%, the target strain error observed in our typical stress relaxation experiments, corresponded to an average stress overshoot of 3+/-1%. Plantar tissue in compression is sensitive to small target strain errors that can result in stress errors that are several fold larger. The extent to which the overshoot may affect the peak stress will likely differ in magnitude for other soft tissues and

  5. Effects of drying conditions, admixtures and specimen size on shrinkage strains

    International Nuclear Information System (INIS)

    Al-Saleh, Saleh A.; Al-Zaid, Rajeh Z.

    2006-01-01

    The paper presents the results of an experimental investigation on the effects of drying conditions, specimen size and presence of plasticizing admixture on the development of shrinkage strains. The measurements are taken in a harsh (50 deg. C and 5% R.H.) and a moderate environment (28 deg. C and 50% R.H.). The results include strain development at various levels of cross sections of concrete prisms. The drying conditions are found to be the dominant parameter affecting the shrinkage strain development particularly in specimens of smaller sizes. The effect of plasticizing admixture on shrinkage strains is negligible

  6. Path Independent Polar Effective Plastic Strain (PEPS) Diagram for Sheet Forming

    Science.gov (United States)

    Yoon, Jeong Whan; Stoughton, Thomas B.

    This paper reviews a pre-strain effect on necking limit of sheet metal, and discusses the importance of this phenomenon to industrial applications. The paper also discusses a solution to this challenge including adaption of the stress diagram. A new type of forming limit diagram, based on a Polar plot of the Effective Plastic Strain (PEPS) is proposed that appears to be an effective solution to the problem of nonlinear effects, with advantages of the familiar strain-based diagram for linear loading, and without the strain-hardening limitations of the stress diagram, or non-intuitive aspects of the alternate Cartesian diagrams based on effective plastic strain. The benefits and limitations of each method are discussed.

  7. Effect of particle shapes on effective strain gradient of SiC particle reinforced aluminum composites

    Science.gov (United States)

    Liu, X.; Cao, D. F.; Mei, H.; Lei, Z. T.; Liu, L. S.

    2013-03-01

    The stress increments depend not only on the plastic strain but also on the gradient of plastic strain, when the characteristic length scale associated with non-uniform plastic deformation is on the order of microns. In the present research, the Taylor-based nonlocal theory of plasticity (TNT plasticity), with considering both geometrically necessary dislocations and statistically stored dislocations, is applied to investigated the effect of particle shapes on the strain gradient and mechanical properties of SiC particle reinforced aluminum composites (SiC/Al composites). Based on this theory, a two-dimensional axial symmetry cell model is built in the ABAQUS finite element code through its USER-ELEMENT (UEL) interface. Some comparisons with the classical plastic theory demonstrate that the effective stress predicted by TNT plasticity is obviously higher than that predicted by classical plastic theory. The results also demonstrate that the irregular particles cause higher effective gradient strain which is attributed to the fact that angular shape particles give more geometrically.

  8. Residual effects of successive exposure of soybean Bradyrhizobium strains to aluminium on solid defined medium

    Directory of Open Access Journals (Sweden)

    Campo Rubens José

    2001-01-01

    Full Text Available The aim of these studies was to investigate whether residual toxic effects of exposing soybean root nodule bacteria to Al in a solid defined media (SDM alter tolerance to Al, survival, sensitivity to antibiotics, N2 fixation effectiveness and genetic diversity of Bradyrhizobium strains. After being exposed four times to Al, strains showed variation in Al tolerance but there was no evidence of change in their original Al tolerance, sensitivity to the antibiotics or genetic diversity. Exposure of Bradyrhizobium strains to SDM plus Al did not alter biological N2 fixation effectiveness of five strains. Strain SEMIA 587 showed a reduction in its N2 fixation effectiveness but it seems that it was just a superficial toxic effect because one single passage through the plant eliminated this effect. Residual Al did not cause increases in Al tolerance and reductions in the survival and N2 fixation effectiveness of Bradyrhizobium strains USDA 143, SEMIA 586, SEMIA 5019, SEMIA 5039 and SEMIA 5073. It also did not alter the resistance to antibiotics of strains USDA 143, SEMIA 5039 and SEMIA 5073, and the genetic diversity of the strains SEMIA 587 and SEMIA 5019.

  9. Short communication: Antiproliferative effect of 8 different Lactobacillus strains on K562 cells.

    Science.gov (United States)

    Tuo, Yanfeng; Jiang, Shujuan; Qian, Fang; Mu, Guangqing; Liu, Peng; Guo, Yuanji; Ma, Changlu

    2015-01-01

    Some strains of Lactobacillus genus have antiproliferative activities against cancer cells. However, until now, the exact effector molecules of Lactobacillus strains with anticancer activity have not been identified. The aim of the present study was to explore which fraction of the Lactobacillus cells exerts the highest antiproliferative effect. For this purpose, the heat-killed bacterial cells, bacterial cell wall extract, and genomic DNA of 8 Lactobacillus strains were prepared to assess their antiproliferative activities against human myeloid leukemia cell lines K562. The heat-killed bacterial cells of the 8 lactobacilli strains exerted antiproliferative effect on K562 cells, and the inhibition rates exerted by the heat-killed bacterial cells of the strains G15AL, M5AL, SB31AL, SB5AL, and T3AL were significantly higher than those exerted by the cell walls and genomic DNA of the strains. The bacterial DNA of G15AL exerted higher antiproliferative effect on K562 cells. The exact effector molecules and the effect mechanism of the strains should be further explored for the application of these strains as probiotic strains or bioactive probiotic molecules. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  10. An atomistic investigation of the effect of strain on frictional properties of suspended graphene

    Directory of Open Access Journals (Sweden)

    Qingshun Bai

    2016-05-01

    Full Text Available We performed molecular dynamics (MD simulations of a diamond probe scanned on a suspended graphene to reveal the effect of strain on the frictional properties of suspended graphene. The graphene was subjected to some certain strain along the scanning direction. We compared the friction coefficient obtained from different normal loads and strain. The results show that the friction coefficient can be decreased about one order of magnitude with the increase of the strain. And that can be a result of the decreased asymmetry of the contact region which is caused by strain. The synthetic effect of potential energy and the fluctuation of contact region were found to be the main reason accounting for the fluctuation of the friction force. The strain can reduce the fluctuation of the contact region and improve the stability of friction.

  11. Effect of probiotic Lactobacillus strains in children with atopic dermatitis

    DEFF Research Database (Denmark)

    Rosenfeldt, Vibeke; Benfeldt, Eva; Nielsen, Susanne Dam

    2003-01-01

    : In a double-blind, placebo-controlled, crossover study, 2 probiotic Lactobacillus strains (lyophilized Lactobacillus rhamnosus 19070-2 and Lactobacillus reuteri DSM 122460) were given in combination for 6 weeks to 1- to 13-year-old children with AD. The patients' evaluations were registered after each...

  12. In vitro effect of some quinolone antibiotics on strains of ...

    African Journals Online (AJOL)

    A total of 30 different strains of Staphylococcus aureus were isolated from some selected wards of Madonna University Teaching Hospital (MUTH), Elele, Nigeria, using blood agar and nutrient agar. All the isolates were subjected to some selected quinolones (ciprofloxacin, pefloxacin, ofloxacin, norfloxcin and sparfloxacin) ...

  13. Effect of biosurfactant from two strains of Pseudomonas on ...

    African Journals Online (AJOL)

    PRECIOUS

    2009-12-01

    Dec 1, 2009 ... and alcohol production from sugars like glucose, sucrose, mannitol, glycerol and lactose. No growth was observed at 45 and 4°C. Optimum growth was found at 37°C. Both the Pseudomonas strains produced fluorescent green pigment in the mineral salt culture media. Extraction of biosurfactant.

  14. Effect of ropy and capsular exopolysaccharides producing strain of ...

    African Journals Online (AJOL)

    The contribution of selected ropy and capsular Lactobacillus plantarum 162RM on texture of fermented milk as well as on the functionality of kareish cheese was established in this study. The cell suspension of this strain was used in combination with commercial starter cultures MY900 (Lactobacillus delbrueckii ssp.

  15. 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...

  16. ADP1 Affects Plant Architecture by Regulating Local Auxin Biosynthesis

    Science.gov (United States)

    Li, Shibai; Qin, Genji; Novák, Ondřej; Pěnčík, Aleš; Ljung, Karin; Aoyama, Takashi; Liu, Jingjing; Murphy, Angus; Gu, Hongya; Tsuge, Tomohiko; Qu, Li-Jia

    2014-01-01

    Plant architecture is one of the key factors that affect plant survival and productivity. Plant body structure is established through the iterative initiation and outgrowth of lateral organs, which are derived from the shoot apical meristem and root apical meristem, after embryogenesis. Here we report that ADP1, a putative MATE (multidrug and toxic compound extrusion) transporter, plays an essential role in regulating lateral organ outgrowth, and thus in maintaining normal architecture of Arabidopsis. Elevated expression levels of ADP1 resulted in accelerated plant growth rate, and increased the numbers of axillary branches and flowers. Our molecular and genetic evidence demonstrated that the phenotypes of plants over-expressing ADP1 were caused by reduction of local auxin levels in the meristematic regions. We further discovered that this reduction was probably due to decreased levels of auxin biosynthesis in the local meristematic regions based on the measured reduction in IAA levels and the gene expression data. Simultaneous inactivation of ADP1 and its three closest homologs led to growth retardation, relative reduction of lateral organ number and slightly elevated auxin level. Our results indicated that ADP1-mediated regulation of the local auxin level in meristematic regions is an essential determinant for plant architecture maintenance by restraining the outgrowth of lateral organs. PMID:24391508

  17. Strain rate effect on sooting characteristics in laminar counterflow diffusion flames

    KAUST Repository

    Wang, Yu

    2016-01-20

    The effects of strain rate, oxygen enrichment and fuel type on the sooting characteristics of counterflow diffusion flames were studied. The sooting structures and relative PAH concentrations were measured with laser diagnostics. Detailed soot modeling using recently developed PAH chemistry and surface reaction mechanism was performed and the results were compared with experimental data for ethylene flames, focusing on the effects of strain rates. The results showed that increase in strain rate reduced soot volume fraction, average size and peak number density. Increase in oxygen mole fraction increased soot loading and decreased its sensitivity on strain rate. The soot volume fractions of ethane, propene and propane flames were also measured as a function of global strain rate. The sensitivity of soot volume fraction to strain rate was observed to be fuel dependent at a fixed oxygen mole fraction, with the sensitivity being higher for more sooting fuels. However, when the soot loadings were matched at a reference strain rate for different fuels by adjusting oxygen mole fraction, the dependence of soot loading on strain rate became comparable among the tested fuels. PAH concentrations were shown to decrease with increase in strain rate and the dependence on strain rate is more pronounced for larger PAHs. Soot modeling was performed using detailed PAH growth chemistry with molecular growth up to coronene. A qualitative agreement was obtained between experimental and simulation results, which was then used to explain the experimentally observed strain rate effect on soot growth. However, quantitatively, the simulation result exhibits higher sensitivity to strain rate, especially for large PAHs and soot volume fractions.

  18. Strain Effect on Electronic Structure and Work Function in α-Fe2O3 Films

    Directory of Open Access Journals (Sweden)

    Li Chen

    2017-03-01

    Full Text Available We investigate the electronic structure and work function modulation of α-Fe2O3 films by strain based on the density functional method. We find that the band gap of clean α-Fe2O3 films is a function of the strain and is influenced significantly by the element termination on the surface. The px and py orbitals keep close to Fermi level and account for a pronounced narrowing band gap under compressive strain, while unoccupied dz2 orbitals from conduction band minimum draw nearer to Fermi level and are responsible for the pronounced narrowing band gap under tensile strain. The spin polarized surface state, arising from localized dangling-bond states, is insensitive to strain, while the bulk band, especially for pz orbital, arising from extended Bloch states, is very sensitive to strain, which plays an important role for work function decreasing (increasing under compressive (tensile strain in Fe termination films. In particular, the work function in O terminated films is insensitive to strain because pz orbitals are less sensitive to strain than that of Fe termination films. Our findings confirm that the strain is an effective means to manipulate electronic structures and corrosion potential.

  19. Strain Effect on Electronic Structure and Work Function in α-Fe₂O₃ Films.

    Science.gov (United States)

    Chen, Li; Shi, Changmin; Li, Xiaolong; Mi, Zhishan; Wang, Dongchao; Liu, Hongmei; Qiao, Lijie

    2017-03-09

    We investigate the electronic structure and work function modulation of α-Fe₂O₃ films by strain based on the density functional method. We find that the band gap of clean α-Fe₂O₃ films is a function of the strain and is influenced significantly by the element termination on the surface. The p x and p y orbitals keep close to Fermi level and account for a pronounced narrowing band gap under compressive strain, while unoccupied d z ₂ orbitals from conduction band minimum draw nearer to Fermi level and are responsible for the pronounced narrowing band gap under tensile strain. The spin polarized surface state, arising from localized dangling-bond states, is insensitive to strain, while the bulk band, especially for p z orbital, arising from extended Bloch states, is very sensitive to strain, which plays an important role for work function decreasing (increasing) under compressive (tensile) strain in Fe termination films. In particular, the work function in O terminated films is insensitive to strain because p z orbitals are less sensitive to strain than that of Fe termination films. Our findings confirm that the strain is an effective means to manipulate electronic structures and corrosion potential.

  20. Strain-dependent Effects of Acute, Chronic, and Withdrawal from Chronic Nicotine on Fear Conditioning

    OpenAIRE

    Portugal, George S.; Wilkinson, Derek S.; Kenney, Justin W.; Sullivan, Colleen; Gould, Thomas J.

    2011-01-01

    The effects of nicotine on cognitive processes such as learning and memory may play an important role in the addictive liability of tobacco. However, it remains unknown whether genetic variability modulates the effects of nicotine on learning and memory. The present study characterized the effects of acute, chronic, and withdrawal from chronic nicotine administration on fear conditioning, somatic signs, and the elevated plus maze in 8 strains of inbred mice. Strain-dependent effects of acute ...

  1. ADP-ribose-specific chromatin-affinity purification for investigating genome-wide or locus-specific chromatin ADP-ribosylation.

    Science.gov (United States)

    Bisceglie, Lavinia; Bartolomei, Giody; Hottiger, Michael O

    2017-09-01

    Protein ADP-ribosylation is a structurally heterogeneous post-translational modification (PTM) that influences the physicochemical and biological properties of the modified protein. ADP-ribosylation of chromatin changes its structural properties, thereby regulating important nuclear functions. A lack of suitable antibodies for chromatin immunoprecipitation (ChIP) has so far prevented a comprehensive analysis of DNA-associated protein ADP-ribosylation. To analyze chromatin ADP-ribosylation, we recently developed a novel ADP-ribose-specific chromatin-affinity purification (ADPr-ChAP) methodology that uses the recently identified ADP-ribose-binding domains RNF146 WWE and Af1521. In this protocol, we describe how to use this robust and versatile method for genome-wide and loci-specific localization of chromatin ADP-ribosylation. ADPr-ChAP enables bioinformatic comparisons of ADP-ribosylation with other chromatin modifications and is useful for understanding how ADP-ribosylation regulates biologically important cellular processes. ADPr-ChAP takes 1 week and requires standard skills in molecular biology and biochemistry. Although not covered in detail here, this technique can also be combined with conventional ChIP or DNA analysis to define the histone marks specifically associated with the ADP-ribosylated chromatin fractions and dissect the molecular mechanism and functional role of chromatin ADP-ribosylation.

  2. Effect of antibiotic ceftriaxone on elimination of ABI and GV3101 strains of Agrobacterium tumefaciens

    Directory of Open Access Journals (Sweden)

    Gorbatyuk I. R.

    2015-12-01

    Full Text Available Aim. To find out, at which concentration the antibiotic ceftriaxone of β-lactam group causes the elimination of ABI and GV3101 strains of Agrobacterium tumefaciens. Methods. The disc diffusion method. Results. Antibiotic ceftriaxone was used for the cell elimination of the Agrobacterium tumefaciens ABI strain for the first time. The same zones of inhibition were observed when using the 400 mg/l ceftriaxone and 500 mg/l cefotaxime solutions for both Agrobacterium strains (ABI and GV3101 studied. Conclusions. Ceftriaxone inhibits the Agrobacterium growth more effectively than cefotaxime. The ceftriaxone concentration for elimination of ABI and GV3101 Agrobacterium tumefaciens strains is 400 mg/l.

  3. Effect of in site strain on passivated property of the 316L stainless steels.

    Science.gov (United States)

    Jinlong, Lv; Tongxiang, Liang; Chen, Wang; Ting, Guo

    2016-04-01

    The effect of the strain of 316L stainless steel on its corrosion resistance in borate buffer solution was investigated by in site tensile test and the electrochemical impedance spectroscopy measurements. It was found that the corrosion resistance of the 316L stainless steel decreased with the increasing of in site strain. The lower corrosion resistance of the stainless steel during in site strain was mainly attributed to the higher doping concentration in passive film. Especially, with the increasing of in site strain, the concentrations of acceptor (i.e., cation vacancies) in the passive films significantly increased. More acceptor concentrations reduced the compactness of the passive film and its corrosion resistance. Moreover, two exponential relationships were found between in site strain and the charge transfer resistance of the passive film and between in site strain and total doping concentrations in passive film, respectively. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Cultivar and Rhizobium Strain Effects on the Symbiotic Performance of Pea (Pisum sativum)

    DEFF Research Database (Denmark)

    Skøt, Leif

    1983-01-01

    The symbiotic performance of four pea (Pisum sativum L.) cultivars in combination with each of four strains of Rhizobium leguminosarum was studied in growth chamber experiments in order to estimate the effects of cultivars, strains and cultivar × strain interaction on the variation in dry weight, N...... content and dry weight/N ratio. At harvest 63 days after planting, cultivars accounted for 75% of the variation in dry weight, while the Rhizobium strains accounted for 63% of the variation in N-content and 70% of the variation in dry weight/N ratio. Cultivar × strain interactions were statistically...... significant, but of minor quantitative importance, accounting for 5–15% of the total variation. Rhizobium strains also influenced the partitioning of N between reproductive and vegetative plant parts and between root and shoot biomass....

  5. Human Achilles tendon plasticity in response to cyclic strain: effect of rate and duration.

    Science.gov (United States)

    Bohm, Sebastian; Mersmann, Falk; Tettke, Martin; Kraft, Marc; Arampatzis, Adamantios

    2014-11-15

    High strain magnitude and low strain frequency are important stimuli for tendon adaptation. Increasing the rate and duration of the applied strain may enhance the adaptive responses. Therefore, our purpose was to investigate the effect of strain rate and duration on Achilles tendon adaptation. The study included two experimental groups (N=14 and N=12) and a control group (N=13). The participants of the experimental groups exercised according to a reference protocol (14 weeks, four times a week), featuring a high strain magnitude (~6.5%) and a low strain frequency (0.17 Hz, 3 s loading/3 s relaxation) on one leg and with either a higher strain rate (one-legged jumps) or a longer strain duration (12 s loading) on the other leg. The strain magnitude and loading volume were similar in all protocols. Before and after the interventions, the tendon stiffness, Young's modulus and cross-sectional area were examined using magnetic resonance imaging, ultrasound and dynamometry. The reference and long strain duration protocols induced significantly increased (P<0.05) tendon stiffness (57% and 25%), cross-sectional area (4.2% and 5.3%) and Young's modulus (51% and 17%). The increases in tendon stiffness and Young's modulus were higher in the reference protocol. Although region-specific tendon hypertrophy was also detected after the high strain rate training, there was only a tendency of increased stiffness (P=0.08) and cross-sectional area (P=0.09). The control group did not show any changes (P=0.86). The results provide evidence that a high strain magnitude, an appropriate strain duration and repetitive loading are essential components for an efficient adaptive stimulus for tendons. © 2014. Published by The Company of Biologists Ltd.

  6. Phylogenetic approach for inferring the origin and functional evolution of bacterial ADP-ribosylation superfamily.

    Science.gov (United States)

    Chellapandi, P; Sakthishree, S; Bharathi, M

    2013-09-01

    Bacterial ADP-ribosyltransferases (BADPRTs) are extensively contributed to determine the strain-specific virulence state and pathogenesis in human hosts. Understanding molecular evolution and functional diversity of the BADPRTs is an important standpoint to describe the fundamental behind in the vaccine designing for bacterial infections. In the present study, we have evaluated the origin and functional evolution of conserved domains within the BADPRTs by analyzing their sequence-function relationship. To represent the evolution history of BADPRTs, phylogenetic trees were constructed based on their protein sequence, structure and conserved domains using different evolutionary programs. Sequence divergence and genetic diversity were studied herein to deduce the functional evolution of conserved domains across the family and superfamily. The results of sequence similarity search have shown that three hypothetical proteins (above 90%) were identical to the members of BADPRTs and their functions were annotated by phylogenetic approach. Phylogenetic analysis of this study has revealed the family members of BADPRTs were phylogenetically related to one another, functionally diverged within the same family, and dispersed into closely related bacteria. The presence of core substitution pattern in the conserved domains would determine the family-specific function of BADPRTs. Functional diversity of the BADPRTs was exclusively distinguished by Darwinian positive selection (diphtheria toxin C and pertussis toxin S) and neutral selection (arginine ADP-ribosyltransferase, enterotoxin A and binary toxin A) acting on the existing domains. Many of the family members were sharing their sequence-specific features from members in the arginine ADP-ribosyltransferase family. Conservative functions of members in the BADPRTs have shown to be expanded only within closely related families, and retained as such in pathogenic bacteria by evolutionary process (domain duplication or

  7. Involvement of cytosolic NAD+ glycohydrolase in cyclic ADP-ribose metabolism.

    Science.gov (United States)

    Matsumura, N; Tanuma, S

    1998-12-18

    The NAD+ glycohydrolase homogeneously purified from bovine brain cytosol was found to catalyze the synthesis and hydrolysis of cyclic ADP-ribose (cADPR). Although the formation of cADPR from NAD+ does not exceed about 2% of the reaction products, the cyclase activity is clearly evidenced by its conversion of NGD+ to cyclic GDP-ribose (cGDPR), which cannot be hydrolyzed to GDPR. Importantly, a steep increase in cADPR hydrolytic activity was observed at cADPR concentrations above 60 microM, which could be reproduced on a Hill curve with a Hill coefficient of 2. Thus, the allosteric binding of cADPR to the NAD+ glycohydrolase (E) molecule promotes the hydrolysis of cADPR. These results suggest that NAD+ hydrolysis to ADPR and nicotinamide catalyzed by the NAD+ glycohydrolase occurs through the formation of a cADPR. E. cADP-ribosyl complex. The low production of cADPR by NAD+ glycohydrolase compared with invertebrate ADP-ribosyl cyclase is believed to be attributable to the fast hydrolysis of cADPR by the allosteric effect of cADPR bound to the same enzyme that produces it. Copyright 1998 Academic Press.

  8. Nodulation and N2 fixation effectiveness of Bradyrhizobium strains in symbiosis with Adzuki Bean, Vigna angularis

    Directory of Open Access Journals (Sweden)

    Dušica Delić

    2010-04-01

    Full Text Available In pot experiment, one isolate Knj from a Serbian soil, four strains of Bradyrhizobium japonicum and three strains of Bradyrhizobium spp. were examined for the effect on adzuki bean nodulation and effectiveness in symbiotic N2 fixation. All the tested strains produced root nodules in adzuki bean. Strains of B. japonicum showed high potential of N2 fixation, particularly 525 and 542. B. japonicum strains resulted 65-71% shoot dry weight and 99-138% total N content of uninoculated control with full N content (100%. No significant difference was found between the plants inoculated with Bradyrhizobium spp. strains and uninoculated control plants without N (40-42 and 42% shoot dry weight, respectively, which indicated symbiotic N2 fixation inactivity of the Bradyrhizobium spp. strains. Knj strain had the middle position (56% shoot dry weight. These data showed that B. japonicum 525 and 542 strains could be used in further investigations in order to apply them as inoculants in microbiological N fertilizers.

  9. Effect of vaccination of pigs against experimental infection with high and low virulence Mycoplasma hyopneumoniae strains.

    Science.gov (United States)

    Villarreal, I; Maes, D; Vranckx, K; Calus, D; Pasmans, F; Haesebrouck, F

    2011-02-17

    This study investigated the infection pattern and lung lesion development in pigs caused by a low and highly virulent Mycoplasma hyopneumoniae strain at 4 and 8 weeks (w) post infection (PI). It also determined the efficacy of a commercial inactivated whole-cell vaccine against infection with each one of these M. hyopneumoniae strains. Ninety piglets free of M. hyopneumoniae were selected, and 40 of them were randomly vaccinated during their first week of life. At weaning, all piglets were allocated to 10 different groups and housed in pens with absolute filters. At 4 weeks of age, pigs were inoculated intratracheally with either a highly virulent M. hyopneumoniae strain, a low virulent strain or with sterile culture medium. Half of all animals were euthanized at 4 w PI, while the remaining half was euthanized at 8 w PI. Coughing was assessed daily, and lung lesions, immunofluorescence (IF), bacteriological analysis and nested PCR were assessed after necropsy. It was demonstrated that contrary to the highly virulent strain, the low virulent strain required more than 4 weeks PI (commonly accepted as the standard infection model) to reach maximum clinical symptoms. Vaccination significantly reduced clinical symptoms, macroscopic and microscopic lung lesions in pigs infected with the highly virulent strain. This effect was more pronounced at 4 than at 8 weeks PI. Protective efficacy was also observed in pigs infected with the low virulent strain, but the effect was less pronounced than on the highly virulent strain. Copyright © 2011 Elsevier Ltd. All rights reserved.

  10. Investigating the effect of the poly(ADP-ribose) polymerase inhibitor 5-aminoisoquinolinone and the Na⁺-H⁺ exchanger inhibitor zoniporide on isolated perfused rat hearts during ischemia-reperfusion injury.

    Science.gov (United States)

    Akkoc, H; Gurkan, A; Kelle, I; Hekimoglu, A T; Erdinc, M

    2013-10-01

    The goal of this study was to investigate whether the combination of the Poly(ADP-ribose) polymerase inhibitor 5-aminoisoquinolinone (5-AIQ) and the Na+-H+ exchanger inhibitor zoniporide (ZN) provides increased protection against ischemia-reperfusion (I/R) injury. Rats were separated into 5 groups (n=8): Group 1: Control group, Group 2: I/R, Group 3: 5-AIQ, Group 4: ZN and Group 5: Mix (5-AIQ+ZN). Isolated rat hearts were subjected to 30 min of global ischemia, followed by 120 min of reperfusion using Langendorff's apparatus. In groups 3, 4 and 5, 5-AIO (7.5 μM/L) and ZN (50 nM/L) were added to Tyrode Solution after a stabilization period. The level of lactate dehydrogenase (LDH) was determined in the sample perfusate. Myocardial infarct size was determined using the triphenyltetrazolium chloride method. Heart tissues were stored to determine the malondialdehyde (MDA) content, total oxidant status (TOS) and total antioxidant status (TAS). Compared to the 5-AIQ and ZN groups, there was no notable difference in the LDH, MDA, TOS, TAS and hemodynamic parameters of the 5-AIQ+ZN group, but myocardial infarct size decreased significantly, as determined by volume and weight measurements. These results show that the combined use of Zoniporide and 5-Aminoisoquinolinone provides increased protection against I/R injury by reducing myocardial infarct size. © Georg Thieme Verlag KG Stuttgart · New York.

  11. Evidence for dose-dependent effects on plant growth by Stenotrophomonas strains from different origins.

    Science.gov (United States)

    Suckstorff, I; Berg, G

    2003-01-01

    To assess the influence of Stenotrophomonas on plants, the interaction of 16 Stenotrophomonas strains from clinical and environmental sources with strawberry plant seedlings was analysed. In vitro, all Stenotrophomonas strains influenced plant growth when applied to seedlings. Whereas most of the Stenotrophomonas strains promoted root growth and hair development, a statistically significantly negative influence on the length of stem was found. Although strains from a clinical origin also showed statistically significant effects on plants, this was generally lower when compared with environmental strains. For three selected strains, a strong dose-dependent effect was observed for all parameters. In vitro, a correlation was found between plant growth promotion and production of a plant growth hormone, indole-3-acetic acid (IAA). Xanthomonas campestris, a phylogenetically very closely related species to Stenotrophomonas, was used as a phytopathogenic control. It too confirmed the reduction of plant growth in this in vitro system. Independent of their origin, Stenotrophomonas strains can produce IAA in vitro and subsequently, influence plant growth. The effect of Stenotrophomonas presence on plants was dose-dependent. The dose-dependent effect of Stenotrophomonas, a bacterium of both biotechnological and medical interest, is of great interest for biocontrol applications of plant-associated strains. This paper is the first report that clearly demonstrates the phytopathogenic capacity of Stenotrophomonas.

  12. X-ray determination of crystallite size and effect of lattice strain on ...

    Indian Academy of Sciences (India)

    interesting to study the effect of lattice strains on the Debye–. Waller factors of this metal. Inagaki et al (1971, .... This shows that while milling is enough to create strains, it affects the particle size to a measurable extent. A typical Hall–. Williamson plot is shown in figure 1 for Pt after grinding for 15 h. 4. Results and discussion.

  13. Poly(ADP-ribose) polymerase inhibition reduces tumor necrosis factor-induced inflammatory response in rheumatoid synovial fibroblasts

    NARCIS (Netherlands)

    García, S.; Bodaño, A.; Pablos, J. L.; Gómez-Reino, J. J.; Conde, C.

    2008-01-01

    To investigate the effect of poly(ADP-ribose) polymerase (PARP) inhibition on the production of inflammatory mediators and proliferation in tumour necrosis factor (TNF)-stimulated fibroblast-like synoviocytes (FLS) from patients with rheumatoid arthritis (RA). Cultured FLS from patients with RA were

  14. Shock Compression and Strain Rate Effect in Composites and Polymers

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Eric [Los Alamos National Laboratory

    2012-06-20

    Polymers are increasingly being utilized as monolithic materials and composite matrices for structural applications historically reserved for metals. High strain and high strain-rate applications in aerospace, defense, and automotive industries have lead to interest in utilizing the ability of many polymers to withstand extensions to failure of several hundred percent, often without localization or necking and their strong rate dependence. A broad range of characterization techniques will be presented for semi-crystalline polymers and composites including elastic-plastic fracture, split Hopkinson pressure bar (SHPB), plate impact including soft-recovery and lateral gage measurements and Taylor Impact. Gas-launched, plate impact experiments have been performed on pedigreed PTFE 7C, mounted in momentum-trapped, shock assemblies, with impact pressures above and below the phase II to phase III crystalline transition to probe subtle changes in the crystallinity, microstructure, and mechanical response of PTFE. Observed strong anisotropy on the hugoniot and spall behavior of fiber-reinforced composites will be discussed. Polymers are known to exhibit a strong dependence of the yield stress on temperature and strain-rate that are often observed to be linear for temperature and logarithmic for strain-rate. Temperature and strain-rate dependence will be reviewed in terms of classic time-temperature superposition and an empirical mapping function for superposition between temperature and strain-rate. The recent extension of the new Dynamic-Tensile-Extrusion (Dyn-Ten-Ext) technique to probe the dynamic tensile responses of polymers will be discussed, where more irregular deformation and stochastic-based damage and failure mechanisms than the stable plastic elongation and shear instabilities observed that in metals. The opportunity to use of Dyn-Ten-Ext to probe incipient damage at very high strain-rate by linking in situ and post mortem experimental observations with high

  15. EFFECTIVE FRACTURE ENERGY OF ULTRA-HIGH-PERFORMANCE FIBRE-REINFORCED CONCRETE UNDER INCREASED STRAIN RATES

    Directory of Open Access Journals (Sweden)

    Radoslav Sovják

    2014-10-01

    Full Text Available The main objective of this paper is to contribute to the development of ultra-high performance fibre reinforced concrete (UHPFRC with respect to its effective fracture energy. Effective fracture energy was investigated in this paper considering different fibre volume fractions and different strain rates. It was concluded that the effective fracture energy is dependent on the strain rate. In addition, it was found that higher fibre volume fractions tend to decrease the sensitivity of the UHPFRC to increased strain rates.

  16. Strain rate effect on the cyclic deformation response of UFG Al alloys

    Energy Technology Data Exchange (ETDEWEB)

    Malekjani, Shokoufeh, E-mail: s.malekjani@deakin.edu.au [Centre for Material and Fibre Innovation, Deakin University, Geelong 3216 (Australia); Hodgson, Peter D., E-mail: peter.hodgson@deakin.edu.au [Centre for Material and Fibre Innovation, Deakin University, Geelong 3216 (Australia); Cizek, Pavel, E-mail: pavel.cizek@deakin.edu.au [Centre for Material and Fibre Innovation, Deakin University, Geelong 3216 (Australia); Hilditch, Timothy B., E-mail: tim.hilditch@deakin.edu.au [School of Engineering, Deakin University, Geelong 3216 (Australia)

    2012-06-30

    Highlights: Black-Right-Pointing-Pointer We studied the cyclic deformation response of UFG Al to strain rate change. Black-Right-Pointing-Pointer The materials considered for this study were commercially pure Al and 2024 Al alloy. Black-Right-Pointing-Pointer The cyclic softening rate in UFG pure Al was not strain rate sensitive. Black-Right-Pointing-Pointer However, the appearance of shear bands was found strain rate sensitive. Black-Right-Pointing-Pointer The stable behaviour of UFG 2024 Al alloy was also found insensitive to strain rate. - Abstract: Commercially pure aluminium and 2024 Al alloy were cryo-rolled and annealed to produce ultrafine grained (UFG) microstructures. Both materials were cyclically deformed under a fully reversed total strain amplitude control condition at different frequencies to study strain rate effects. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to identify microstructural changes and explain the mechanical properties. The cyclic stress response showed significant softening in commercial purity Al that was due to shear band formation and grain coarsening within these shear bands. While there was no strain rate sensitivity for commercial purity Al in terms of the mechanical response, the shear bands became noticeably more defined at lower strain rates. 2024 Al alloy had a cyclically stable response and microstructure that was not affected by strain rate.

  17. Interaction of rate- and size-effect using a dislocation density based strain gradient viscoplasticity model

    Science.gov (United States)

    Nguyen, Trung N.; Siegmund, Thomas; Tomar, Vikas; Kruzic, Jamie J.

    2017-12-01

    Size effects occur in non-uniform plastically deformed metals confined in a volume on the scale of micrometer or sub-micrometer. Such problems have been well studied using strain gradient rate-independent plasticity theories. Yet, plasticity theories describing the time-dependent behavior of metals in the presence of size effects are presently limited, and there is no consensus about how the size effects vary with strain rates or whether there is an interaction between them. This paper introduces a constitutive model which enables the analysis of complex load scenarios, including loading rate sensitivity, creep, relaxation and interactions thereof under the consideration of plastic strain gradient effects. A strain gradient viscoplasticity constitutive model based on the Kocks-Mecking theory of dislocation evolution, namely the strain gradient Kocks-Mecking (SG-KM) model, is established and allows one to capture both rate and size effects, and their interaction. A formulation of the model in the finite element analysis framework is derived. Numerical examples are presented. In a special virtual creep test with the presence of plastic strain gradients, creep rates are found to diminish with the specimen size, and are also found to depend on the loading rate in an initial ramp loading step. Stress relaxation in a solid medium containing cylindrical microvoids is predicted to increase with decreasing void radius and strain rate in a prior ramp loading step.

  18. Strain rate effects on fracture behavior of Austempered Ductile Irons

    Science.gov (United States)

    Ruggiero, Andrew; Bonora, Nicola; Gentile, Domenico; Iannitti, Gianluca; Testa, Gabriel; Hörnqvist Colliander, Magnus; Masaggia, Stefano; Vettore, Federico

    2017-06-01

    Austempered Ductile Irons (ADIs), combining high strength, good ductility and low density, are candidates to be a suitable alternative to high-strength steels. Nevertheless, the concern about a low ductility under dynamic loads often leads designers to exclude cast irons for structural applications. However, results from dynamic tensile tests contradict this perception showing larger failure strain with respect to quasistatic data. The fracture behaviour of ADIs depends on damage mechanisms occurring in the spheroids of graphite, in the matrix and at their interface, with the matrix (ausferrite) consisting of acicular ferrite in carbon-enriched austenite. Here, a detailed microstructural analysis was performed on the ADI 1050-6 deformed under different conditions of strain rates, temperatures, and states of stress. Beside the smooth specimens used for uniaxial tensile tests, round notched bars to evaluate the ductility reduction with increasing stress triaxiality and tophat geometries to evaluate the propensity to shear localization and the associated microstructural alterations were tested. The aim of the work is to link the mechanical and fracture behavior of ADIs to the load condition through the microstructural modifications that occur for the corresponding deformation path.

  19. Effect of iron on vanadium (001) strained surface magnetism

    Energy Technology Data Exchange (ETDEWEB)

    Elzain, M; Al-Barwani, M; Gismelseed, A; Al-Rawas, A; Yousif, A; Widatallah, H; Bouziane, K; Al-Omari, I, E-mail: elzain@squ.edu.o [Department of Physics, College Of Science, Box 36, Sultan Qaboos University, Al Khod 123 (Oman)

    2010-03-01

    The magnetism of the vanadium (001) surface has been a controversial subject on both theoretical and experiment fronts. Both strongly ferromagnetic and paramagnetic phases were reported. We have used the first principle full-potential linearized-augmented plane waves (FP-LAPW) as implemented in WIEN2k package to study the magnetic properties of strained surfaces of vanadium films as a function of film thickness. We found that for films thicker than about 11 monolayers, the magnetism of the strained surfaces converge to a constant value of about 0.15{mu}{sub B}. Introduction of Fe monolayers and impurities at the centre of the films affects the magnetic structure of thin films but has no influence on the surface magnetism of thicker films. For Fe monolayers positioned at the centre of thick films, the Fe atoms maintain magnetic moment of order 0.86{mu}{sub B}, a quadruple splitting of order -0.3 mm/s and a small negative isomer shift, while an Fe impurity has vanishing hyperfine fields and magnetic moment. In addition we have varied the location of the Fe monolayer and impurity within the V films and found that their position affects the surface magnetism.

  20. File list: His.Adp.10.AllAg.White_adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adp.10.AllAg.White_adipocytes mm9 Histone Adipocyte White adipocytes SRX800009 ...http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Adp.10.AllAg.White_adipocytes.bed ...

  1. File list: His.Adp.50.AllAg.White_adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adp.50.AllAg.White_adipocytes mm9 Histone Adipocyte White adipocytes SRX800009 ...http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Adp.50.AllAg.White_adipocytes.bed ...

  2. File list: Unc.Adp.05.Unclassified.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Adp.05.Unclassified.AllCell hg19 Unclassified Unclassified Adipocyte SRX813776,...SRX813777 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Adp.05.Unclassified.AllCell.bed ...

  3. File list: Unc.Adp.10.AllAg.Brown_preadipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Adp.10.AllAg.Brown_preadipocytes mm9 Unclassified Adipocyte Brown preadipocytes... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Unc.Adp.10.AllAg.Brown_preadipocytes.bed ...

  4. Effect of carbaryl (carbamate insecticide) on acetylcholinesterase activity of two strains of Daphnia magna (Crustacea, Cladocera).

    Science.gov (United States)

    Toumi, Hela; Bejaoui, Mustapha; Touaylia, Samir; Burga Perez, Karen F; Ferard, Jean François

    2016-11-01

    The present study was designed to investigate the effect of carbaryl (carbamate insecticide) on the acetylcholinesterase activity in two strains (same clone A) of the crustacean cladoceran Daphnia magna. Four carbaryl concentrations (0.4, 0.9, 1.8 and 3.7 µg L(-1)) were compared against control AChE activity. Our results showed that after 48 h of carbaryl exposure, all treatments induced a significant decrease of AChE activities whatever the two considered strains. However, different responses were registered in terms of lowest observed effect concentrations (LOEC: 0.4 µg L(-1) for strain 1 and 0.9 µg L(-1) for strains 2) revealing differences in sensitivity among the two tested strains of D. magna. These results suggest that after carbaryl exposure, the AChE activity responses can be also used as a biomarker of susceptibility. Moreover, our results show that strain1 is less sensitive than strain 2 in terms of IC50-48 h of AChE activity. Comparing the EC50-48 h of standard ecotoxicity test and IC50-48 h of AChE inhibition, there is the same order of sensitivity with both strains.

  5. Potassium 2-(1-hydroxypentyl)-benzoate inhibits ADP-induced rat platelet aggregation through P2Y1-PLC signaling pathways.

    Science.gov (United States)

    Yang, Hongyan; Xu, Shaofeng; Li, Jiang; Wang, Ling; Wang, Xiaoliang

    2015-09-01

    Potassium 2-(1-hydroxypenty1)-benzoate (dl-PHPB) is a new drug candidate for treatment of ischemic stroke with antiplatelet effect. In this study, we investigated the mechanisms of dl-PHPB in inhibiting platelet aggregation. The ADP-activated P2Y1-Gq-PLC and P2Y12-Gi-AC pathways were observed, respectively. Intravenous injection of dl-PHPB (1.3, 3.9, 12.9 mg/kg) significantly inhibited ADP-, collagen-, and arachidonic acid-induced rat platelet aggregation in a dose-dependent manner, and dl-PHPB had a relatively more potent inhibitory effect on ADP-induced rat platelet aggregation than other agonists. Dl-PHPB also showed a decreased expression of CD62P (a marker for platelet activation) mediated by ADP. Both dl-PHPB and ticlopidine (P2Y12 receptor antagonist) decreased cytoplasmic Ca(2+) concentration. But, dl-PHPB did not reverse the inhibition of PGE1-induced platelet cAMP formation by ADP, which was different from ticlopidine. Further, dl-PHPB instead of ticlopidine showed increasing phospholipase C-β phosphorylation (ser(1105)). The m-3M3FBS, a phospholipase C activator, attenuated the inhibitory effect of dl-PHPB on ADP-induced platelet aggregation and enhanced IP1 accumulation in rat platelets. Dl-PHPB decreased IP1 accumulation induced by ADP but had no effect on IP1 level enhanced by m-3M3FBS. Our results suggest that dl-PHPB has a potent antiplatelet effect, which is mainly through blockade of P2Y1 receptor-PLC-IP3 pathway and decreasing cytoplasmic calcium.

  6. Strain-specific battery of tests for domains of mania: effects of valproate, lithium and imipramine

    Directory of Open Access Journals (Sweden)

    Shlomit Flaisher-Grinberg

    2010-04-01

    Full Text Available The lack of efficient animal models for bipolar disorder (BPD, especially for the manic pole, is a major factor hindering the research of its pathophysiology and the development of improved drug treatments. The present study was designed to identify an appropriate mouse strain for modeling some behavioral domains of mania and to evaluate the effects of drugs using this strain. The study compared the behavior of four strains: Black Swiss, C57Bl/6, CBA/J and A/J mice in a battery of tests that included spontaneous activity; sweet solution preference; light/dark box; resident-intruder; forced-swim and amphetamine-induced hyperactivity. Based on the ‘manic-like’ behavior demonstrated by the Black Swiss strain, the study evaluated the effects of the mood stabilizers valproate and lithium and of the antidepressant imipramine in the same tests using this strain. Results indicated that lithium and valproate attenuate the ‘manic-like’ behavior of Black Swiss mice whereas imipramine had no effects. These findings suggest that Black Swiss mice might be a good choice for modeling several domains of mania and distinguishing the effects of drugs on these specific domains. However, the relevance of the behavioral phenotype of Black Swiss mice to the biology of BPD is unknown at this time and future studies will investigate molecular differences between Black Swiss mice and other strains and asess the interaction between strain and mood stabilizing treatment.

  7. THE EFFECT OF STRAIN RATE ON FRACTURE TOUGHNESS OF HUMAN CORTICAL BONE: A FINITE ELEMENT STUDY

    Science.gov (United States)

    Ural, Ani; Zioupos, Peter; Buchanan, Drew; Vashishth, Deepak

    2011-01-01

    Evaluating the mechanical response of bone under high loading rates is crucial to understanding fractures in traumatic accidents or falls. In the current study, a computational approach based on cohesive finite element modeling was employed to evaluate the effect of strain rate on fracture toughness of human cortical bone. Two-dimensional compact tension specimen models were simulated to evaluate the change in initiation and propagation fracture toughness with increasing strain rate (range: 0.08 to 18 s−1). In addition, the effect of porosity in combination with strain rate was assessed using three-dimensional models of microcomputed tomography-based compact tension specimens. The simulation results showed that bone’s resistance against the propagation of fracture decreased sharply with increase in strain rates up to 1 s−1 and attained an almost constant value for strain rates larger than 1 s−1. On the other hand, initiation fracture toughness exhibited a more gradual decrease throughout the strain rates. There was a significant positive correlation between the experimentally measured number of microcracks and the fracture toughness found in the simulations. Furthermore, the simulation results showed that the amount of porosity did not affect the way initiation fracture toughness decreased with increasing strain rates, whereas it exacerbated the same strain rate effect when propagation fracture toughness was considered. These results suggest that strain rates associated with falls lead to a dramatic reduction in bone’s resistance against crack propagation. The compromised fracture resistance of bone at loads exceeding normal activities indicates a sharp reduction and/or absence of toughening mechanisms in bone during high strain conditions associated with traumatic fracture. PMID:21783112

  8. Radioprotective effect of garlic extract on some bacterial strains with different radiation sensitivities

    International Nuclear Information System (INIS)

    Tawfik, Z.S.; Abushady, M.R.

    1992-01-01

    The radioprotective effect of garlic on four bacterial strains with different degrees of radiation sensitivities was investigated. The presence of garlic led to an increase in d-10 value of Ps. Aeruginosa, S. aureus and S. typhimurium by 160%, 50%, and 30% respectively. The protective efficiency of garlic against radiation was noticed to be proportional to its concentration in a given inoculum size. Garlic extract up to 180 micro liter per 10 8 inoculum size of B. cereus showed no protective effect. This fact was attributed to the existence of sulphur compounds in the given strain. Higher garlic concentrations appeared to affect the cloning efficiency of a given strain. 4fig., 2tab

  9. D.C. electrical conductivity measurements on ADP single crystals ...

    Indian Academy of Sciences (India)

    Unknown

    In order to understand qualitatively whether the added impurity has entered into the ADP lattice or not, we carried out the density measurements by using the flotation tech- nique. Carbon tetrachloride of density, 1⋅594 g/cc and bromoform of density, 2⋅890 g/cc, are respectively the lower density and higher density liquids, ...

  10. Determinants of rice output among ADP contact farmers in mining ...

    African Journals Online (AJOL)

    The study analyzed factors affecting rice output among Agricultural Development Programme (ADP) contact farmers in the mining and non mining locations of IVO LGA of Ebonyi State, Nigeria. Multistage random sampling technique was used to select agricultural circles and rice farmers. The sample size was 120 rice ...

  11. Niacin, poly(ADP-ribose) polymerase-1 and genomic stability

    NARCIS (Netherlands)

    Hageman, G.J.; Stierum, R.H.

    2001-01-01

    Nicotinic acid (NA) and nicotinamide (NAM), commonly called niacin, are the dietary precursors for NAD+ (nicotinamide adenine dinucleotide), which is required for DNA synthesis, as well as for the activity of the enzyme poly(ADP-ribose) polymerase-1 (PARP-1; EC 2.4.2.30) for which NAD+ is the sole

  12. Out-of-plane strain effect on silicon-based flexible FinFETs

    KAUST Repository

    Ghoneim, Mohamed T.

    2015-06-21

    Summary form only given. We report out-of-plane strain effect on silicon based flexible FinFET, with sub 20 nm wide fins and hafnium silicate based high-κ gate dielectric. Since ultra-thin inorganic solid state substrates become flexible with reduced thickness, flexing induced strain does not enhance performance. However, detrimental effects arise as the devices are subject to various out-of-plane stresses (compressive and tensile) along the channel length.

  13. Strain controlled switching effects in phosphorene and GeS

    Science.gov (United States)

    Li, B. W.; Wang, Y.; Xie, Y. Q.; Zhu, L.; Yao, K. L.

    2017-10-01

    By performing first principles calculations within the combined approach of density functional theory and nonequilibrium Green’s function technique, we have designed some nanoelectronic devices to explore the ferroelastic switching of phosphorene and phosphorene analogs GeS. With the structure swapping along the zigzag direction and armchair direction, band gap transformed at different states due to their anisotropic phosphorene-like structure. From the initial state to the middle state, the band gap becomes progressively smaller, after that, it becomes wide. By analyzing transmission coefficients, it is found that the transport properties of phosphorene and GeS can be controlled by a uniaxial strain. The results also manifest that GeS has great potential to fabricate ferroic nonvolatile memory devices, because its relatively high on/off transmission coefficient ratio (∼1000) between the two stable ferroelastic states.

  14. Stress and strain effects on the properties of composite superconductors

    International Nuclear Information System (INIS)

    Welch, D.O.

    1982-01-01

    Practical superconductors for use in the production of high magnetic fields are generally in the form of composites of filaments of superconducting material embedded in a matrix of normally conducting material. Lorentz forces which arise during magnet operation are examples of sources of external stress, while internal stresses can arise during the fabrication of the composite superconductor, primarily due to differential thermal contraction between different materials in the composite. The properties of superconducting compounds are often sensitive functions of the elastic strain state in the compound; consequently there is a strong coupling between the mechanical and electrical properties of composite superconductors. The basic features of this phenomenon will be illustrated by a discussion of the properties of simple composite superconductors

  15. Effect of uniaxial strain on the current of (6,6) finite armchair carbon nano tube

    International Nuclear Information System (INIS)

    Faizabadi, S. E.; Kargar, Z.

    2012-01-01

    In this paper, the uniaxial strain effect on the electronic properties of (6,6) finite armchair carbon nano tube was investigated by using the Green function technique and Landure-Buttiker formula. It was found that, in (6,6) finite carbon nano tube with 3q and 3q + 1 length, where q is a certain integer, the current was induced by the application of a suitable tensile strain and compressive strain in low voltage, respectively. The current of (6,6) finite carbon nano tube with 3q -1 length was decreased by loading the uniaxial strain. According to the results semiconductor-metal transition in (6,6) finite carbon nano tube and vice versa is observed by applying uniaxial strain.

  16. Effect of surface strain on oxygen adsorption on Zr (0001) surface

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xing [Univ. of Wisconsin-Madison, Madison, WI (United States). Dept. of Engineering Physics; Khafizov, Marat [Idaho National Laboratory (INL), Idaho Falls, ID (United States); Szlufarska, Izabela [Univ. of Wisconsin-Madison, Madison, WI (United States). Dept. of Engineering Physics; Univ. of Wisconsin-Madison, Madison, WI (United States). Dept. of Materials Science and Engineering

    2014-02-01

    The effect of surface strain on oxygen adsorption on Zr (0 0 0 1) surface is investigated by density functional theory (DFT) calculations. It is demonstrated that both surface strain and interactions between oxygen adsorbates influence the adsorption process. Oxygen binding to zirconium becomes stronger as the strain changes from compressive to tensile. When oxygen coverage is low and the oxygen interactions are negligible, surface face-centered cubic sites are the most stable for O binding. At high coverage and under compression, octahedral sites between second and third Zr layers become most favorable because the interactions between adsorbates are weakened by positive charge screening. Calculations with both single-layer adsorption model and multiple-layer adsorption model demonstrate that compressive strain at the Zr/oxide interface will provide a thermodynamic driving force for oxygen to incorporate from the surface into the bulk of Zr, while binding oxygen to the Zr surface will be easier when tensile strain is applied.

  17. Effects of texture on shear band formation in plane strain tension/compression and bending

    DEFF Research Database (Denmark)

    Kuroda, M.; Tvergaard, Viggo

    2007-01-01

    model analysis. Third, shear band developments in plane strain pure bending of a sheet specimen with the typical textures are studied. Regions near the surfaces in a bent sheet specimen are approximately subjected to plane strain tension or compression. From this viewpoint, the bendability of a sheet......In this study, effects of typical texture components observed in rolled aluminum alloy sheets on shear band formation in plane strain tension/compression and bending are systematically studied. The material response is described by a generalized Taylor-type polycrystal model, in which each grain...... are obtained: i.e. the critical strain at the onset of shear banding and the corresponding orientation of shear band. Second, the shear band development in plane strain tension/compression is analyzed by the finite element method. Predictability of the finite element analysis is compared to that of the simple...

  18. The effect of flexoelectricity on the dielectric properties of inhomogeneously strained ferroelectric thin films

    Energy Technology Data Exchange (ETDEWEB)

    Catalan, G [Institut Mediterrani d' Estudis Avancats (IMEDEA), C/Miquel Marques 21, Esporles 07190, Mallorca (Spain); Sinnamon, L J [Department of Pure and Applied Physics, Queen' s University of Belfast, University Road, Belfast BT7 1NN (United Kingdom); Gregg, J M [Department of Pure and Applied Physics, Queen' s University of Belfast, University Road, Belfast BT7 1NN (United Kingdom)

    2004-04-07

    Recent experimental measurements of large flexoelectric coefficients in ferroelectric ceramics suggest that strain gradients can affect the polarization and permittivity behaviour of inhomogeneously strained ferroelectrics. Here we present a phenomenological model of the effect of flexoelectricity on the dielectric constant, polarization, Curie temperature (T{sub C}), temperature of maximum dielectric constant (T{sub m}) and temperature of the onset of reversible polarization (T{sub ferro}) for ferroelectric thin films subject to substrate-induced epitaxial strains that are allowed to relax with thickness, and the qualitative and quantitative predictions of the model are compared with experimental results for (Ba{sub 0.5}Sr{sub 0.5})TiO{sub 3} thin films on SrRuO{sub 3} electrodes. It is shown that flexoelectricity can play an important role in decreasing the maximum dielectric constant of ferroelectric thin films under inhomogeneous in-plane strain, regardless of the sign of the strain gradient.

  19. The effect of flexoelectricity on the dielectric properties of inhomogeneously strained ferroelectric thin films

    International Nuclear Information System (INIS)

    Catalan, G; Sinnamon, L J; Gregg, J M

    2004-01-01

    Recent experimental measurements of large flexoelectric coefficients in ferroelectric ceramics suggest that strain gradients can affect the polarization and permittivity behaviour of inhomogeneously strained ferroelectrics. Here we present a phenomenological model of the effect of flexoelectricity on the dielectric constant, polarization, Curie temperature (T C ), temperature of maximum dielectric constant (T m ) and temperature of the onset of reversible polarization (T ferro ) for ferroelectric thin films subject to substrate-induced epitaxial strains that are allowed to relax with thickness, and the qualitative and quantitative predictions of the model are compared with experimental results for (Ba 0.5 Sr 0.5 )TiO 3 thin films on SrRuO 3 electrodes. It is shown that flexoelectricity can play an important role in decreasing the maximum dielectric constant of ferroelectric thin films under inhomogeneous in-plane strain, regardless of the sign of the strain gradient

  20. Effect of Deforming Temperature and Strain on Abnormal Grain Growth of Extruded FGH96 Superalloy

    Directory of Open Access Journals (Sweden)

    WANG Chaoyuan

    2016-10-01

    Full Text Available Based on the experiments of isothermal forging wedge-shaped samples, Deform-3D numerical simulation software was used to confirm the strain distribution in the wedge-shaped samples. The effect of deforming temperature and strain on abnormal grain growth(AGG in extruded FGH96 superalloy was examined. It is found that when the forging speed is 0.04 mm/s,the critical AGG occurring temperature is 1100℃,and the critical strain is 2%.AGG does not occur within 1000-1070℃,but still shows the feature of ‘critical strain’,and the region with strain of 5%-10% has the largest average grain size.AGG can be avoided and the uniform fine grains can be gained when the strain is not less than 15%.

  1. Strain-specific protective effect of the immunity induced by live malarial sporozoites under chloroquine cover.

    Science.gov (United States)

    Wijayalath, Wathsala; Cheesman, Sandra; Tanabe, Kazuyuki; Handunnetti, Shiroma; Carter, Richard; Pathirana, Sisira

    2012-01-01

    The efficacy of a whole-sporozoite malaria vaccine would partly be determined by the strain-specificity of the protective responses against malarial sporozoites and liver-stage parasites. Evidence from previous reports were inconsistent, where some studies have shown that the protective immunity induced by irradiated or live sporozoites in rodents or humans were cross-protective and in others strain-specific. In the present work, we have studied the strain-specificity of live sporozoite-induced immunity using two genetically and immunologically different strains of Plasmodium cynomolgi, Pc746 and PcCeylon, in toque monkeys. Two groups of monkeys were immunized against live sporozoites of either the Pc746 (n = 5), or the PcCeylon (n = 4) strain, by the bites of 2-4 sporozoite-infected Anopheles tessellates mosquitoes per monkey under concurrent treatments with chloroquine and primaquine to abrogate detectable blood infections. Subsequently, a group of non-immunized monkeys (n = 4), and the two groups of immunized monkeys were challenged with a mixture of sporozoites of the two strains by the bites of 2-5 infective mosquitoes from each strain per monkey. In order to determine the strain-specificity of the protective immunity, the proportions of parasites of the two strains in the challenge infections were quantified using an allele quantification assay, Pyrosequencing™, based on a single nucleotide polymorphism (SNP) in the parasites' circumsporozoite protein gene. The Pyrosequencing™ data showed that a significant reduction of parasites of the immunizing strain in each group of strain-specifically immunized monkeys had occurred, indicating a stronger killing effect on parasites of the immunizing strain. Thus, the protective immunity developed following a single, live sporozoite/chloroquine immunization, acted specifically against the immunizing strain and was, therefore, strain-specific. As our experiment does not allow us to determine the parasite stage at

  2. Effect of Bacteriophages on the Growth of Flavobacterium psychrophilum and Development of Phage-Resistant Strains.

    Science.gov (United States)

    Christiansen, Rói Hammershaimb; Madsen, Lone; Dalsgaard, Inger; Castillo, Daniel; Kalatzis, Panos G; Middelboe, Mathias

    2016-05-01

    The controlling effect of single and multiple phages on the density of Flavobacterium psychrophilum at different initial multiplicity of infection (MOI) was assessed in batch cultures to explore the potential for phage-based treatment of this important fish pathogen. A high initial phage concentration (MOI = 0.3-4) was crucial for efficient viral lysis, resulting in a 10(4)-10(5)-fold reduction of phage-sensitive cells (both single phages and phage cocktails), which was maintained throughout the incubation (>10 days). Following cell lysis, regrowth of phage-resistant strains was examined and resistant strains were isolated for further characterization. The application of a mathematical model allowed simulation of phage-host interactions and resistance development, confirming indications from strain isolations that phage-sensitive strains dominated the regrowing population (>99.8%) at low MOI and phage-resistant strains (>87.8%) dominated at high MOI. A cross-infectivity test covering 68 isolated strains and 22 phages resulted in 23 different host susceptibility patterns, with 20 of the isolates being resistant to all the applied phages. Eleven isolated strains with different susceptibility patterns had lower growth rates (0.093 to 0.31 h(-1)) than the host strain (0.33 h(-1)), while 10 of 14 examined strains had lost the ability to take up specific substrates as shown by BIOLOG profiles. Despite increased selection for phage resistance at high MOI, the results emphasize that high initial MOI is essential for fast and effective control of F. psychrophilum infection and suggest that the small populations of resistant clones had reduced competitive abilities relative to the sensitive ancestral strain.

  3. Effects of equiaxial strain on the differentiation of dental pulp stem cells without using biochemical reagents.

    Science.gov (United States)

    Tabatabaei, F S; Jazayeri, M; Ghahari, P; Haghighipour, N

    2014-09-01

    During orthodontic treatments, applied mechanical forces create strain and result in tooth movement through the alveolar bone. This response to mechanical strain is a fundamental biological reaction. The present study evaluated the effect of equiaxial strain within the range of orthodontic forces on the osteogenic differentiation of human dental pulp stem cells (hDPSCs). Following isolation and culture of hDPSCs, 3rd passage cells were transferred on a silicone membrane covered with collagen. Cell adhesion to the membrane was evaluated under scanning electron microscope (SEM). Cells were divided into three groups: the first group was placed in a conventional culture medium, transferred to an equiaxial stretching device (3% strain for 2 weeks). The positive control was placed in an osteogenic medium with no mechanical strain. The negative control group was placed in the conventional culture medium with no mechanical strain either. Study groups were evaluated for expression ofosteogenic markers (Alkaline phosphatase and Osteopontin) with immunofluorescence and real time PCR. SEM images revealed optimal adhesion of cells to the silicone membrane. Immunofluorescence study demonstrated that osteocalcin expression occurred after 2 weeks in the two groups under mechanical and chemical signals. After application of equiaxial strain, level of expression of osteogenic markers was significantly higher than in the negative and positive control groups. Based on the study results, static equiaxial strain which mimics the types of orthodontic forces can result in differentiation of hDPSCs to osteoblasts. The results obtained may be used in cell therapy and tissue engineering.

  4. Crystal orientation effects on the piezoelectric field of strained zinc-blende quantum-well structures

    DEFF Research Database (Denmark)

    Duggen, Lars; Willatzen, Morten; Lassen, Benny

    2008-01-01

    A three-layered zinc-blende quantum-well structure is analyzed subject to both static and dynamic conditions for different crystal growth directions taking into account piezoelectric effects and lattice mismatch. It is found that the strain component Szz in the quantum-well region strongly depends...... on the crystal growth direction and that a piezoelectric strain contribution exists in zinc blende as in wurtzite, albeit smaller. It is also found in the absence of loss effects that resonance frequencies, giving large strains in the structure, depend strongly on the crystal growth direction. Due to the higher...... symmetry of the zinc-blende structure, we find in a one-dimensional model that piezoelectric effects do not affect strain values for zinc-blende structures grown along the [001] direction in contrast to the corresponding wurtzite result. However, zinc-blende structures grown along a general crystal...

  5. GC-MS-Based Metabonomic Profiling Displayed Differing Effects of Borna Disease Virus Natural Strain Hu-H1 and Laboratory Strain V Infection in Rat Cortical Neurons.

    Science.gov (United States)

    Liu, Siwen; Bode, Liv; Zhang, Lujun; He, Peng; Huang, Rongzhong; Sun, Lin; Chen, Shigang; Zhang, Hong; Guo, Yujie; Zhou, Jingjing; Fu, Yuying; Zhu, Dan; Xie, Peng

    2015-08-17

    Borna disease virus (BDV) persists in the central nervous systems of a wide variety of vertebrates and causes behavioral disorders. Previous studies have revealed that metabolic perturbations are associated with BDV infection. However, the pathophysiological effects of different viral strains remain largely unknown. Rat cortical neurons infected with human strain BDV Hu-H1, laboratory BDV Strain V, and non-infected control (CON) cells were cultured in vitro. At day 12 post-infection, a gas chromatography coupled with mass spectrometry (GC-MS) metabonomic approach was used to differentiate the metabonomic profiles of 35 independent intracellular samples from Hu-H1-infected cells (n = 12), Strain V-infected cells (n = 12), and CON cells (n = 11). Partial least squares discriminant analysis (PLS-DA) was performed to demonstrate discrimination between the three groups. Further statistical testing determined which individual metabolites displayed significant differences between groups. PLS-DA demonstrated that the whole metabolic pattern enabled statistical discrimination between groups. We identified 31 differential metabolites in the Hu-H1 and CON groups (21 decreased and 10 increased in Hu-H1 relative to CON), 35 differential metabolites in the Strain V and CON groups (30 decreased and 5 increased in Strain V relative to CON), and 21 differential metabolites in the Hu-H1 and Strain V groups (8 decreased and 13 increased in Hu-H1 relative to Strain V). Comparative metabonomic profiling revealed divergent perturbations in key energy and amino acid metabolites between natural strain Hu-H1 and laboratory Strain V of BDV. The two BDV strains differentially alter metabolic pathways of rat cortical neurons in vitro. Their systematic classification provides a valuable template for improved BDV strain definition in future studies.

  6. The effect of strain for N2 dissociation on Fe surfaces

    DEFF Research Database (Denmark)

    Logadottir, Ashildur; Nørskov, Jens Kehlet

    2001-01-01

    The effect of strain on N-2 dissociation on Fe surfaces has been investigated by the use of density functional calculations (DFT). To study the strain effect we did calculations on fcc-Fe(111) surfaces with different lattice constants. These calculations show that by expanding the surface lattice...... in the overlayer. Calculations on another closed packed Fe surface, bcc-Fe(110) are also reported. (C) 2001 Elsevier Science B.V. All rights reserved.......The effect of strain on N-2 dissociation on Fe surfaces has been investigated by the use of density functional calculations (DFT). To study the strain effect we did calculations on fcc-Fe(111) surfaces with different lattice constants. These calculations show that by expanding the surface lattice...... constant, the barrier for the N2 dissociation is lowered. The same effect can be achieved by having a pseudomorphic Fe layer on a Ru(0001) surface. The dissociation barrier on the strained Fe overlayer is lower than on the unperturbed bcc-Fe(110) surface by an amount given primarily by the strain...

  7. Effects of relative density and accumulated shear strain on post-liquefaction residual deformation

    Directory of Open Access Journals (Sweden)

    J. Kim

    2013-10-01

    Full Text Available The damage caused by liquefaction, which occurs following an earthquake, is usually because of settlement and lateral spreading. Generally, the evaluation of liquefaction has been centered on settlement, that is, residual volumetric strain. However, in actual soil, residual shear and residual volumetric deformations occur simultaneously after an earthquake. Therefore, the simultaneous evaluation of the two phenomena and the clarification of their relationship are likely to evaluate post-liquefaction soil behaviors more accurately. Hence, a quantitative evaluation of post-liquefaction damage will also be possible. In this study, the effects of relative density and accumulated shear strain on post-liquefaction residual deformations were reviewed through a series of lateral constrained-control hollow cylindrical torsion tests under undrained conditions. In order to identify the relationship between residual shear and residual volumetric strains, this study proposed a new test method that integrates monotonic loading after cyclic loading, and K0-drain after cyclic loading – in other words, the combination of cyclic loading, monotonic loading, and the K0 drain. In addition, a control that maintained the lateral constrained condition across all the processes of consolidation, cyclic loading, monotonic loading, and drainage was used to reproduce the anisotropy of in situ ground. This lateral constrain control was performed by controlling the axial strain, based on the assumption that under undrained conditions, axial and lateral strains occur simultaneously, and unless axial strain occurs, lateral strain does not occur. The test results confirmed that the recovery of effective stresses, which occur during monotonic loading and drainage after cyclic loading, respectively, result from mutually different structural restoration characteristics. In addition, in the ranges of 40–60% relative density and 50–100% accumulated shear strain, relative

  8. Local Effects on Strain Seismogram at Matsushiro Seismological Observatory - 1. Love Waves

    Directory of Open Access Journals (Sweden)

    Taishi Okamoto

    2007-01-01

    Full Text Available We proposed a simple method to evaluate local effects on a strain seismogram, and applied the method to investigation of the effects at Matsushiro Seismological Observatory, Japan Meteorological Agency, central Japan, for a Love wave in a period range of 170 - 400 sec. First, we took a ratio of EW to NS component strain for a Love wave on a timefrequency plane. Although NS and EW component strain for a Love wave travelling in any direction have the same amplitude theoretically, the ratio of observed EW to NS component strain was 0.7. Next, we compared the strain seismogram with a velocity seismogram recorded with STS-1 broadband seismometer. A ratio of a partial derivative of a displacement field with respect to time to that with respect to wave propagation direction equals a phase velocity of the wave theoretically. Utilizing the fact, we estimated the phase velocity of a Love wave using the observed velocity and strain seismogram, after NS component strain had been multiplied by 0.7. The result was 24% smaller than the theoretical phase velocity. Finally, we compared the velocity seismogram with other velocity seismograms recorded by STS-1 seismometers at F-net observation stations near Matsushiro and by STS-2 seismometer at Matsushiro, and found that the every deviation from Matsushiro was less than 10%. From these results, we conclude that the EW and NS component strain seismograms have been amplified by factors of 1.32 and 1.88 for a Love wave, respectively. This fact, which may be because of local geology and/or topography effects, must be taken into account when the strain seismogram is used for seismological applications such as the CMT inversion and research on earth¡¦s free oscillations.

  9. Necking of anisotropic micro-films with strain-gradient effects

    DEFF Research Database (Denmark)

    Legarth, Brian Nyvang

    2008-01-01

    Necking of stubby micro-films of aluminum is investigated numerically by considering tension of a specimen with an initial imperfection used to onset localisation. Plastic anisotropy is represented by two different yield criteria and strain-gradient effects are accounted for using the visco......-plastic finite strain model. Furthermore, the model is extended to isotropic anisotropic hardening (evolving anisotropy). For isotropic hardening plastic anisotropy affects the predicted overall nominal stress level, while the peak stress remains at an overall logarithmic strain corresponding to the hardening...... exponent. This holds true for both local and nonlocal materials. Anisotropic hardening delays the point of maximum overall nominal stress....

  10. Annealing and etching effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A.F.; Sáez-Rodríguez, D.

    2017-01-01

    Thermal annealing and chemical etching effects on the strain and stress sensitivity of polymer optical fibre based sensors are investigated. Bragg grating sensors have been photo-inscribed in PMMA optical fibre and their strain and stress sensitivity has been characterised before and after any...... annealing or etching process. The annealing and etching processes have been tried in different sequence in order to investigate their impact on the sensor's performance. Results show with high confidence that fibre annealing can improve both strain and stress sensitivities. The fibre etching can also...

  11. Stress and strain effects on the electronic structure and optical properties of ScN monolayer

    Science.gov (United States)

    Tamleh, Shirin; Rezaei, Ghasem; Jalilian, Jaafar

    2018-02-01

    Based on the density functional theory, electronic and optical properties of a monolayer scandium nitride structure have been studied under different strain conditions. Our results indicate that both biaxial compressive and tensile strain effects lead to change the band gap of this structure with different rates. Also, optical absorption spectrum peaks experience an obvious red and blue shifts with the exerting of tensile and compressive strains, respectively. Our results express that ScN monolayer can be the promising candidate for the future nano-base electrical and optical devices.

  12. Reheat cracking of austenitic stainless steels - pre-strain effect on intergranular damage

    International Nuclear Information System (INIS)

    Auzoux, Q.

    2004-01-01

    Welding process induces strain in 316 stainless steel affected zones. Their microstructure was reproduce by rolling of three different steels (316L, 316L(N) et 316H). Traction, creep and relaxation tests were performed at 550 deg C and 600 deg C on smooth, notched and pre-cracked specimens. Pre-strain by rolling increases the hardness and the creep resistance because of the high dislocation density but decreases ductility because of the fast development of intergranular damage. This embrittlement leads to crack propagation during relaxation tests on pre-strained steels without distinction in respect to their carbon or nitrogen content. A new intergranular damage model was built using local micro-cracks measurements and finite elements analysis. Pre-strain effect and stress triaxiality ratio effect are reproduced by the modelling so that the reheat cracking risk near welds can now be estimated. (author)

  13. Strain effects on three-dimensional, two-dimensional, and one-dimensional silicon logic devices: Predicting the future of strained silicon

    Science.gov (United States)

    Baykan, Mehmet O.; Thompson, Scott E.; Nishida, Toshikazu

    2010-11-01

    Using a classification scheme based on carrier confinement type (electrostatic and spatial) and the degrees of freedom of the mobile carriers (3DOF, 2DOF, and 1DOF), strain effects on 3DOF to 1DOF silicon logic devices are compared from quantum confinement and device geometry perspectives. For these varied device geometries and types, the effects of strain-induced band splitting and band warping on the modification of the average conductivity effective mass and carrier scattering rates are evaluated. It is shown that the beneficial effects of strain-induced band splitting are the most effective for devices with little or no initial band splitting and become less so for devices with already large built-in band splitting. For these devices with large splitting energy, the potential for strain-induced carrier conductivity mass reduction through repopulation of lower energy bands and the suppression of optical intervalley phonon scattering are limited. On the other hand, for all devices without spatial confinement, a comparable amount of effective mass reduction occurs through favorable strain-induced band warping. Under spatial carrier confinement, much higher strain levels with respect to unconfined or electrically confined devices are required to observe strain-induced band warping in the band structure, with larger strain requirements as the confinement dimension decreases. In electrically confined volume-inversion devices, the favorable strain type required for carrier mass reduction results in increased surface scattering by bringing the carrier centroid closer to gate surfaces. However, for spatially confined volume-inversion devices, the favorable mechanical strain does not alter the carrier distribution in the device cross section. Consequently, strain is expected to be more effective in modification of low field carrier transport in electrically confined volume-inversion devices and less for spatially confined devices, with respect to conventional 2DOF planar

  14. Ceftriaxone and tetracycline effect on biofilm-formation strains of Staphylococcus epidermidis

    Directory of Open Access Journals (Sweden)

    O. I. Sidashenko

    2014-04-01

    Full Text Available 122 strains of staphylococci were identified. Among the examined 122 clinical strains of staphylococci, 67 strains belonged to coagulase-positive, and 55 strains to the coagulase-negative ones. According to the study of physiological and biochemical properties, it was found that 37 strains (30.3% belonged to S. epidermidis species. One of the biological properties of many bacteria is the ability to film formation and these strains attract special attention, since it is known that the film antibiotic resistance is higher than in planktonic cultures. It was determined that 20 strains of those under study were film-forming, 17 strains – non-biofilm forming ones. The film was formed during three days, and settled to the bottom of the plate holes. The clinical (Cl strain of S. epidermidis was sensitive to ceftriaxone and tetracicline. The control (C strains of S. epidermidis were sensitive to ceftriaxone, tetracycline and sizomicine. The study of biofilm growth for 2, 3 and 4 days of incubation was carried out. The maximum rate of biofilm S. epidermidis C was observed during 2–3 days; there is the most intense increase of cells number from 5.2 × 108 CFU/ml, for S. epidermidis Cl to 5.6 × 108 CFU/ml. The effect of ceftriaxone and tetracycline on biofilm formation by 2 investigation strains of S. epidermidis was found. We determined differences in minimal inhibitory concentrations (MIC for planktonic cultures and biofilm of strains under study. It was established that MIC antibiotics inhibited the growth of planktonic cultures on average 2 times lower compared to the MIC which inhibited the biofilm formation. MIC for planktonic culture of S. epidermidis Cl defined for ceftriaxone was equal to 10 mg/ml, and for tetracycline – 1 mg/ml. MIC of ceftriaxone for the control strain was equal to 12 mg/ml, MIC of tetracycline – 0.7 mg/ml. MIC values for dynamics biofilm formation of S. epidermidis Cl strain on the plater were as follows: to

  15. Effect of Attachment Type on Denture Strain in Maxillary Implant Overdentures: Part 1. Overdenture with Palate.

    Science.gov (United States)

    Takahashi, Toshihito; Gonda, Tomoya; Maeda, Yoshinobu

    This study examined the effects of attachments on strain in maxillary implant overdentures supported by two or four implants. A maxillary edentulous model with implants inserted into anterior, premolar, and molar areas was fabricated, and three types of unsplinted attachments-ball, locator, and magnet-were set on the implants distributed under various conditions. Maxillary experimental dentures were fabricated, and two strain gauges were attached at the anterior midline on the labial and palatal sides. A vertical occlusal load of 98 N was applied and shear strain of the dentures was measured. On both sides, magnet attachments resulted in the lowest shear strain, while ball attachments resulted in the highest shear strain under most conditions. However, differences in shear strain among the three attachment types were not significant when supported by four implants, especially molar implants. Shear strain of the maxillary implant overdenture was lowest when using magnet attachments. Magnet attachments mounted on four implants are recommended to prevent denture complications when using maxillary implant overdentures.

  16. Ultrafast laser pulse chirp effects on laser-generated nanoacoustic strains in Silicon.

    Science.gov (United States)

    Bakarezos, M; Tzianaki, E; Petrakis, S; Tsibidis, G; Loukakos, P A; Dimitriou, V; Kosmidis, C; Tatarakis, M; Papadogiannis, N A

    2018-05-01

    Nanoacoustic strains are generated in Silicon by chirped femtosecond laser pulses using thin Titanium films as transducers. We investigate the effect that the generating laser pulse chirp has on the amplitude of the induced strains, manifested as Brillouin oscillations observed in degenerate femtosecond pump-probe transient reflectivity measurements. The strain amplitude is larger when negatively chirped pulses are used, which is attributed to the more efficient conversion of laser pulse light into acoustic strain in the Titanium transducer. Our present studies clearly show that the dependence of the Brillouin amplitude and the lattice strain is a non-monotonous function of the laser chirp parameter. An optimum negative laser pulse chirp is found for which the strain amplitude is maximized. A detailed thermomechanical model satisfactorily supports the experimental findings. In such a way, it is possible to suppress or enhance the induced nanoacoustic strain amplitude, thus all-optically controlling it by at least a factor of two. Copyright © 2018 Elsevier B.V. All rights reserved.

  17. Strain Rate Effect on Tensile Flow Behavior and Anisotropy of a Medium-Manganese TRIP Steel

    Science.gov (United States)

    Alturk, Rakan; Hector, Louis G.; Matthew Enloe, C.; Abu-Farha, Fadi; Brown, Tyson W.

    2018-04-01

    The dependence of the plastic anisotropy on the nominal strain rate for a medium-manganese (10 wt.% Mn) transformation-induced plasticity (TRIP) steel with initial austenite volume fraction of 66% (balance ferrite) has been investigated. The material exhibited yield point elongation, propagative instabilities during hardening, and austenite transformation to α'-martensite either directly or through ɛ-martensite. Uniaxial strain rates within the range of 0.005-500 s-1 along the 0°, 45°, and 90° orientations were selected based upon their relevance to automotive applications. The plastic anisotropy (r) and normal anisotropy (r n) indices corresponding to each direction and strain rate were determined using strain fields obtained from stereo digital image correlation systems that enabled both quasistatic and dynamic measurements. The results provide evidence of significant, orientation-dependent strain rate effects on both the flow stress and the evolution of r and r n with strain. This has implications not only for material performance during forming but also for the development of future strain-rate-dependent anisotropic yield criteria. Since tensile data alone for the subject medium-manganese TRIP steel do not satisfactorily determine the microstructural mechanisms responsible for the macroscopic-scale behavior observed on tensile testing, additional tests that must supplement the mechanical test results presented herein are discussed.

  18. A synchrotron X-ray diffraction study of non-proportional strain-path effects

    International Nuclear Information System (INIS)

    Collins, D.M.; Erinosho, T.; Dunne, F.P.E.; Todd, R.I.; Connolley, T.; Mostafavi, M.; Kupfer, H.; Wilkinson, A.J.

    2017-01-01

    Common alloys used in sheet form can display a significant ductility benefit when they are subjected to certain multiaxial strain paths. This effect has been studied here for a polycrystalline ferritic steel using a combination of Nakajima bulge testing, X-ray diffraction during biaxial testing of cruciform samples and crystal plasticity finite element (CPFE) modelling. Greatest gains in strain to failure were found when subjecting sheets to uniaxial loading followed by balanced biaxial deformation, resulting in a total deformation close to plane-strain. A combined strain of approximately double that of proportional loading was achieved. The evolution of macrostrain, microstrain and texture during non-proportional loading were evaluated by in-situ high energy synchrotron diffraction. The results have demonstrated that the inhomogeneous strain accumulation from non-proportional deformation is strongly dependent on texture and the applied strain-ratio of the first deformation pass. Experimental diffraction evidence is supported by results produced by a novel method of CPFE-derived diffraction simulation. Using constitutive laws selected on the basis of good agreement with measured lattice strain development, the CPFE model demonstrated the capability to replicate ductility gains measured experimentally.

  19. Effect of glucose in removal of microcystin-LR by viable commercial probiotic strains and strains isolated from dadih fermented milk.

    Science.gov (United States)

    Nybom, Sonja M K; Collado, M Carmen; Surono, Ingrid S; Salminen, Seppo J; Meriluoto, Jussi A O

    2008-05-28

    The removal of the cyanobacterial peptide toxin microcystin-LR at 4 and 37 degrees C by six commercial probiotic strains and Lactobacillus plantarum strains IS-10506 and IS-20506 isolated from dadih, Indonesian traditional fermented milk, was assessed in this study. The aim was to evaluate the main factors influencing the viability and metabolic activity of the probiotic strains, as well as their capacity to remove microcystin-LR. Both L. plantarum strains isolated from dadih, as well as Bifidobacterium lactis strains Bb12 and 420, were shown to be more resistant, and >85% remained viable in phosphate-buffered saline (PBS) solution for 48 h of incubation at either temperature, while the viability of the other four commercial bacteria decreased markedly over time. The effect of glucose on viability and removal of toxin was shown to be a strain-specific and strain-dependent property, but in general, the efficiency of microcystin-LR removal increased when glucose was added to the solution. A maximum removal of 95% was observed for L. plantarum strain IS-20506 (37 degrees C, 10 (11) colony-forming units mL(-1)) with 1-2% glucose supplementation and 75% in PBS alone.

  20. Comparative analysis of the complete genome of an Acinetobacter calcoaceticus strain adapted to a phenol-polluted environment.

    Science.gov (United States)

    Zhan, Yuhua; Yan, Yongliang; Zhang, Wei; Chen, Ming; Lu, Wei; Ping, Shuzhen; Lin, Min

    2012-01-01

    The complete genome sequence of Acinetobacter calcoaceticus PHEA-2, a non-pathogenic phenol-degrading bacterium previously isolated from industrial wastewater of an oil refinery in China, has been established. This is the first sequence of an A. calcoaceticus strain. We report here a comparative genomic analysis of PHEA-2 with two other Acinetobacter species having different lifestyles, Acinetobacter baumannii AYE, a pathogenic human-adapted strain, and Acinetobacter baylyi ADP1, a soil-living strain. For a long time, A. calcoaceticus could not be easily distinguished from A. baumannii strains. Indeed, whole-genome comparison revealed high synteny between A. calcoaceticus and A. baumannii genomes, but most genes for multiple drug resistance as well as those presumably involved in pathogenicity were not present in the PHEA-2 genome and phylogenetic analysis showed that A. calcoaceticus differed from A. baumannii antibiotic-susceptible strains. It also revealed that many genes associated with environmental adaptation were acquired by horizontal gene transfer, including an 8-kb phenol degradation gene cluster. A relatively higher proportion of transport-related proteins were found in PHEA-2 than in ADP1 and AYE. Overall, these findings highlight the remarkable capacity of A. calcoaceticus PHEA-2 to effectively adapt to a phenol-polluted wastewater environment. Copyright © 2011 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

  1. Investigations of multiresistance to antibiotics and chemotherapeutics and extended spectrum beta: Lactamase effect (ESBL test in strains E.coli and salmonella originating from domestic animals

    Directory of Open Access Journals (Sweden)

    Mišić Dušan

    2006-01-01

    Full Text Available The presence of multiresistance to the effects of antibiotics and chemotherapeutics and extended spectrum beta-lactamase were examined in 45 strains of E. coli and 35 strains of Salmonella. The strains of E. coli originated from several species of domestic animals: dogs, cats, poultry, and cattle, and 30 strains of Salmonella originated from poultry, 4 strains from cattle, and 1 strain from swine. The presence of the following serovarieties was established using serological examinations: Salmonella Enteritidis 17 strains, Salmonella Gallinarum 1 strain, Salmonella Hartford 5 strains, Salmonella Anatum 1 strain, Salmonella Typhimurium 4 strains, Salmonella Agona 1 strain, Salmonella Infantis 1 strain, Salmonella Thompson var. Berlin 1 strain, Salmonella Tennessee 1 strain, Salmonella Senftenberg 1 strain, Salmonella Glostrup 1 strain, and Salmonella Hadar 1 strain. In the examinations of the listed strains we used antibiogram discs of ampicillin, amoxicillin with clavulanic acid, cephalexin, cephtriaxon, cephotaxim, cephtazidime, aztreonam, gentamycin, chloramphenicol, tetracycline, cyprofloxacine, and a combination of sulphamethoxasole and trimethoprim. The lowest prevalence of multiresistance in E. Coli strains to 3 or more antibiotics was established in dogs 20%, and the highest in 60% strains originating from swine. In 62.88% strains of Salmonella we established sensitivity to all applied antibiotics. Resistance was also established in a small number of the examined strains to ampicillin (11 strains, to tetracycline (5 strains, to amoxicillin with clavulanic acid (5 strains, to sulphamethoxasole with trimethoprim (5 strains, to gentamycin (3 strains, and to cloramphenicol (1 strain. Of all the examined strains of Salmonella, 6 strains originating from poultry exhibited multiresistence. The presence of extended spectrum beta-lactamase effects examined using the ESBL test, was not established in strains of E. coli and Salmonella strains.

  2. Experimental studies on the effect of coherency strains on coarsening kinetics: Current status and future outlook

    Energy Technology Data Exchange (ETDEWEB)

    Muralidharan, G.; Epperson, J.E. [Argonne National Lab., IL (United States); Chen, H. [Illinois Univ., Urbana, IL (United States). Dept. of Materials Science and Engineering

    1994-03-01

    The effect of coherency strains on the coarsening rate constant in Ostwald ripening is an area that is not well understood. We briefly review the extant experimental data on the effect of coherency strains on coarsening rates and explain the need to account for variations in coarsening rates due to composition and diffusivity effects before drawing any conclusions on the dependence of coarsening rates on the misfit parameter. Using the preexisting theories for coarsening rates in multi-component systems, we suggest a simple method to account for the composition dependence of coarsening rates arising from factors unrelated to coherency strain effects. We then present some of the results from our on-going work in the Ni-Al-Si system and explain the relevance of this study to our understanding of coarsening in internally-stressed systems. We conclude the presentation with our views on the direction of future research in this aspect of coarsening.

  3. The influence of loading rates on hardening effects in elasto/viscoplastic strain-hardening materials

    Science.gov (United States)

    De Angelis, Fabio; Cancellara, Donato; Grassia, Luigi; D'Amore, Alberto

    2018-01-01

    In this paper the influence of increasing loading rates on hardening effects is analyzed for rate-dependent elastoplastic materials. The effects of different loading rates on hardening rules are discussed with regard to the constitutive behavior of strain-hardening materials in elasto/viscoplasticity. A suitable procedure for the numerical simulation of rate-sensitive material behavior is illustrated. A comparative analysis is presented on constitutive relations in strain-hardening plasticity without rate effects and with rate effects in order to show the different role played by hardening rules in the rate-sensitivity analysis of elasto/viscoplastic strain-hardening materials. By reporting suitable numerical simulations for the adopted constitutive relations it is shown that when the rate of application of the loading is increased the influence of hardening has a different effect in the mechanical behavior of structures. Computational results and applications are finally illustrated in order to show numerically the different role played by hardening on the plastic strains when the loading rates are incremented for elasto/viscoplastic strain-hardening materials and structures.

  4. Identification of Trichoderma Strain M2 and Related Growth Promoting Effects on Brassica chinensis L.

    Directory of Open Access Journals (Sweden)

    XING Fang-fang

    2017-01-01

    Full Text Available The research took Trichoderma strain as tested strains which isolated from the rhizosphere of healthy and high yield pepper, M2 was classified and identified by combining morphological classification with molecular identification means(rDNA-ITS sequence analysis, whose effect on growth of Brassica chinensis L. was explored, in order to provide superior strains for bio-fertilizer development. After solid fermentation of Trichoderma M2, under the condition of the greenhouse, took some research on the growth promoting effect on Brassica chi nensis L. of Trichoderma M2. The results showed that the strain M2 was identified as Trichoderma harzianum strain. M2 had obvious effects on promoting growth, the SPAD and edible leaf number of Brassica chinensis L. Adding of 5.0×109 cfu M2 had the best effect on increasing the biological yield. Compared with CK, fresh weight and dry weight was increased by 30.26%and 20.08%respectively. Followed by inocula tion of 5.0×108 cfu M2, fresh weight and dry weight was increased by 18.33% and 12.46% respectively. Therefore, M2 showed evident promoting effect on Brassica chinensis L., and had potential application value.

  5. Effect of cyclic pre-strain on low cycle fatigue life at middle high temperature

    International Nuclear Information System (INIS)

    Nakane, Motoki; Kanno, Satoshi; Takagi, Yoshio

    2011-01-01

    This study examined the effect of cyclic plastic pre-strain on low cycle fatigue life at middle high temperature to evaluate the structural integrity of the nuclear components introduced plastic strain to the local portion by the large seismic load. The materials selected in this study were austenitic steel (SUS316NG) and ferritic steel (SFVQ1A, STS410: JIS (Japanese Industrial Standards). The low cycle fatigue tests at RT and middle high temperature (300 degrees C) were carried out using cyclic plastic pre-strained materials. The results obtained here show that the damage by the cyclic plastic pre-strain, which is equivalent to usage factor UF=0.2, does not affect the fatigue lives of the materials. In addition, it is confirmed that the estimation based on the usage factor UF can also be useful for the life prediction at 300 degrees C as well as RT. (author)

  6. Thermal effects on fiber optic strain sensors embedded in graphite-epoxy composites

    Science.gov (United States)

    Rogowski, R. S.; Holben, M. S., Jr.; Heyman, J. S.; Dehart, D. W.; Margulies, Susan

    1990-01-01

    Smart structures deployed in low earth orbit will be exposed to a hostile environment which will include temperature extremes during each orbit as the platform moves from the day to the night side. The stresses due to thermal cycling may compromise the performance of embedded fiber optic strain sensors because of differential thermal expansion of the fiber and the composite material. The effects of elevated temperature and thermal cycling on the performance of a fiber optic strain sensor embedded in a graphite-epoxy tube have been investigated for temperatures from 65 to 220 F. The results indicate that the fiber optic strain sensor measurements correlate well with conventional resistance strain gages attached to the tube.

  7. Lethal effects of a Mexican Beauveria bassiana (Balsamo) strain against Meccus pallidipennis (Stal)

    Science.gov (United States)

    Lino, Zumaquero Rios José; Juventino, López-Tlacomulco José; Raúl, Rojas García; Estibaliz, Sansinenea

    2014-01-01

    The entomopathogenic fungus Beauveria bassiana (Balsamo 1835) Vuillemin is an effective alternative control agent against some agricultural pests and biological vectors of important diseases such as Chagas disease. In this work we studied an isolate of Beauveria bassiana from of the town of San Antonio Rayón, Puebla, Mexico and its entomopathogenic effects on Meccus pallidipennis (Stal 1872). Phylogenetic analysis using molecular comparison of the ITS and EF1α genes, showed that the resulting cladogram places the BUAP 04 strain with a relationship closer to the AFAO 9-6 strain, within the diversity of the B. bassiana sensu lato group. Although there was the possibility that BUAP 04 strain was a direct descendant of strains used in campaigns of biologic control, molecular study allowed us to recognize that it was a different fungus due to numerous inserts. A strain isolated from a T. dimiata was evaluated for pathogenicity against another triatoma (Meccus pallidipennis) species obtaining an LC50 of 4.16 × 106 spores/mL, confirming that the BUAP 04 strain is virulent for M. pallidipennis and could be a good prospect for formulations to control M. pallidipennis. PMID:25242941

  8. Lethal effects of a Mexican Beauveria bassiana (Balsamo) strain against Meccus pallidipennis (Stal).

    Science.gov (United States)

    Lino, Zumaquero Rios José; Juventino, López-Tlacomulco José; Raúl, Rojas García; Estibaliz, Sansinenea

    2014-01-01

    The entomopathogenic fungus Beauveria bassiana (Balsamo 1835) Vuillemin is an effective alternative control agent against some agricultural pests and biological vectors of important diseases such as Chagas disease. In this work we studied an isolate of Beauveria bassiana from of the town of San Antonio Rayón, Puebla, Mexico and its entomopathogenic effects on Meccus pallidipennis (Stal 1872). Phylogenetic analysis using molecular comparison of the ITS and EF1α genes, showed that the resulting cladogram places the BUAP 04 strain with a relationship closer to the AFAO 9-6 strain, within the diversity of the B. bassiana sensu lato group. Although there was the possibility that BUAP 04 strain was a direct descendant of strains used in campaigns of biologic control, molecular study allowed us to recognize that it was a different fungus due to numerous inserts. A strain isolated from a T. dimiata was evaluated for pathogenicity against another triatoma (Meccus pallidipennis) species obtaining an LC50 of 4.16 × 10(6) spores/mL, confirming that the BUAP 04 strain is virulent for M. pallidipennis and could be a good prospect for formulations to control M. pallidipennis.

  9. Lethal effects of a Mexican Beauveria bassiana (Balsamo strain against Meccus pallidipennis (Stal

    Directory of Open Access Journals (Sweden)

    Zumaquero Rios José Lino

    2014-06-01

    Full Text Available The entomopathogenic fungus Beauveria bassiana (Balsamo 1835 Vuillemin is an effective alternative control agent against some agricultural pests and biological vectors of important diseases such as Chagas disease. In this work we studied an isolate of Beauveria bassiana from of the town of San Antonio Rayón, Puebla, Mexico and its entomopathogenic effects on Meccus pallidipennis (Stal 1872. Phylogenetic analysis using molecular comparison of the ITS and EF1α genes, showed that the resulting cladogram places the BUAP 04 strain with a relationship closer to the AFAO 9-6 strain, within the diversity of the B. bassiana sensu lato group. Although there was the possibility that BUAP 04 strain was a direct descendant of strains used in campaigns of biologic control, molecular study allowed us to recognize that it was a different fungus due to numerous inserts. A strain isolated from a T. dimiata was evaluated for pathogenicity against another triatoma (Meccus pallidipennis species obtaining an LC50 of 4.16 x 10(6 spores/mL, confirming that the BUAP 04 strain is virulent for M. pallidipennis and could be a good prospect for formulations to control M. pallidipennis.

  10. Differences in the regulation by poly(ADP-ribose) of repair of DNA damage from alkylating agents and ultraviolet light according to cell type

    Energy Technology Data Exchange (ETDEWEB)

    Cleaver, J.E.; Bodell, W.J.; Morgan, W.F.; Zelle, B.

    1983-08-10

    Inhibition of poly(ADP-ribose) synthesis by 3-aminobenzamide in various human and hamster cells influenced the responses to DNA damage from methyl methanesulfonate, but not from ultraviolet light. After exposure to methyl methanesulfonate, 3-aminobenzamide increased the strand break frequency in all cell types studied, but only stimulated repair replication in lymphoid and HeLa cells, suggesting these are independent effects. 3-Aminobenzamide also inhibited the pathway for de novo synthesis of DNA purines, suggesting that some of its effects may be due to disturbance of precursor pathways and irrelevant to the role of poly(ADP-ribose) in repair. Previous claims that 3-aminobenzamide stimulates repair synthesis after exposure to UV light are probably artifacts, because the stimulations are only observed in lymphocytes in the presence of a high concentration of hydroxyurea that itself inhibits repair. The initial inhibition of semiconservative DNA synthesis and the excision of the major alkylation products and pyrimidine dimers were unaffected by 3-aminobenzamide. In general poly(ADP-ribose) synthesis appears to be uniquely involved in regulating the ligation stage of repair of alkylation damage but not ultraviolet damage. By regulating the ligation efficiency, poly(ADP-ribosylation) modulates the dynamic balance between incision and ligation, so as to minimize the frequency of DNA breaks. The ligation stage of repair of UV damage appears different and is not regulated by poly(ADP-ribosylation).

  11. Effects of strains on growth performances of triploid bighead catfish, Clarias macrocephalus Günther, 1864

    Directory of Open Access Journals (Sweden)

    Satid Chatchaiphan

    2016-07-01

    Full Text Available Despite its importance, limited empirical information is available on the effects of parental strains on the performance of triploid aquatic animals, especially of tropical species. The present study was conducted to evaluate the impacts of strains on the growth performance of the triploid bighead catfish (Clarias macrocephalus Günther, 1864 which was produced using cold shock (7 °C, 25 min shock duration, applied to newly fertilized eggs obtained from all possible crosses between two catfish strains. The fingerlings of each group were reared until they were age 240 d. At age 60 d, the triploid fish had a lower specific growth rate (SGR, absolute growth rate (AGR, body length and body weight than the diploid counterparts. However, at harvest (age 240 d body length and body weight were not different between the two groups while SGR of the cold shock group was higher than the diploid during age 121–240 d. The results revealed that parental strains did not show significant direct effects on the growth performance of triploids, but the interaction between paternal strain × shock was significant for the following traits: body length at age 90 d, body weight at age 90 d and 120 d, AGR for age 61–90 d, and SGR for age 61–90 d and 91–120 d. The interaction between paternal × maternal strain × shock was significant for body length, body weight at age 180 d and AGR for age 121–180 d. These results suggested that the growth performance of triploid C. macrocephalus cannot be enhanced by improving the parental strains; rather, improvement may be accomplished by selecting the parental strains based on triploid performance.

  12. Effects of Martensite Development on Lattice Strain Evolution during ...

    African Journals Online (AJOL)

    mclieia2

    earth body. In chemical processes, turbo machinery, water treatment power generation and aerospace technology, unsteady oscillatory free convective flow is of very high importance. ... rotating. it was shown that the effects of magnetic field and rotating ... magnetic field. In the absence of rotation, the magnetic field.

  13. Effects of Martensite Development on Lattice Strain Evolution during ...

    African Journals Online (AJOL)

    mclieia2

    discussed for various effects of material parameters on the velocity, temperature and concentration profiles. KEYWORDS: ... water purification, energy transfer in cooling towers, power generation and flow in a desert cooler, a combination of heat and mass transfer problems with chemical reactions are of great importance.

  14. Strain-dependent effects of clinical echovirus 30 outbreak isolates at the blood-CSF barrier

    Directory of Open Access Journals (Sweden)

    Tobias Dahm

    2018-02-01

    Full Text Available Abstract Background Echovirus (E 30 (E-30 meningitis is characterized by neuroinflammation involving immune cell pleocytosis at the protective barriers of the central nervous system (CNS. In this context, infection of the blood-cerebrospinal fluid barrier (BCSFB, which has been demonstrated to be involved in enteroviral CNS pathogenesis, may affect the tight junction (TJ and adherens junction (AJ function and morphology. Methods We used an in vitro human choroid plexus epithelial (HIBCPP cell model to investigate the effect of three clinical outbreak strains (13-311, 13-759, and 14-397 isolated in Germany in 2013, and compared them to E-30 Bastianni. Conducting transepithelial electrical resistance (TEER, paracellular dextran flux measurement, quantitative real-time polymerase chain reaction (qPCR, western blot, and immunofluorescence analysis, we investigated TJ and AJ function and morphology as well as strain-specific E-30 infection patterns. Additionally, transmission electron and focused ion beam microscopy electron microscopy (FIB-SEM was used to evaluate the mode of leukocyte transmigration. Genome sequencing and phylogenetic analyses were performed to discriminate potential genetic differences among the outbreak strains. Results We observed a significant strain-dependent decrease in TEER with strains E-30 Bastianni and 13-311, whereas paracellular dextran flux was only affected by E-30 Bastianni. Despite strong similarities among the outbreak strains in replication characteristics and particle distribution, strain 13-311 was the only outbreak isolate revealing comparable disruptive effects on TJ (Zonula Occludens (ZO 1 and occludin and AJ (E-cadherin morphology to E-30 Bastianni. Notwithstanding significant junctional alterations upon E-30 infection, we observed both para- and transcellular leukocyte migration across HIBCPP cells. Complete genome sequencing revealed differences between the strains analyzed, but no explicit correlation

  15. Strain rate effects in nuclear steels at room and higher temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Solomos, G. E-mail: george.solomos@jrc.it; Albertini, C.; Labibes, K.; Pizzinato, V.; Viaccoz, B

    2004-04-01

    An investigation of strain rate, temperature and size effects in three nuclear steels has been conducted. The materials are: ferritic steel 20MnMoNi55 (vessel head), austenitic steel X6CrNiNb1810 (upper internal structure), and ferritic steel 26NiCrMo146 (bolting). Smooth cylindrical tensile specimens of three sizes have been tested at strain rates from 0.001 to 300 s{sup -1}, at room and elevated temperatures (400-600 deg. C). Full stress-strain diagrams have been obtained, and additional parameters have been calculated based on them. The results demonstrate a clear influence of temperature, which amounts into reducing substantially mechanical strengths with respect to RT conditions. The effect of strain rate is also shown. It is observed that at RT the strain rate effect causes up shifting of the flow stress curves, whereas at the higher temperatures a mild downshifting of the flow curves is manifested. Size effect tendencies have also been observed. Some implications when assessing the pressure vessel structural integrity under severe accident conditions are considered.

  16. Effects of mean strain on the random cyclic stress-strain relations of 0Cr18Ni10Ti pipe steel

    International Nuclear Information System (INIS)

    Zhao Yongxiang; Yang Bing

    2005-01-01

    Experimental study is performed for the effects of the mean strain on the random cyclic stress-strain relations of the new nuclear material, 0Cr18Ni10Ti pipe steel. From saving the size of specimens, an improved maximum likelihood fatigue test method is proposed to operate the present strain-controlled fatigue tests. Six straining ratios, -1, -0.52, -0.22, 0.029, 0.18, and 0.48, respectively, are applied to study the effects. Fatigue test has been carried out on totally 104 specimens. The test results reveal that the material exhibits a Masing behaviour and the saturation hysteresis loops under the six ratios hold an entirely relaxation effect of mean stress. There is no effectively method for the description of the mean straining effects under this case. Previous Zhao's random stress-strain relations are therefore applied to characterizing effectively the scattering test data under the six ratios on a basis of Ramberg-Osgood equation. Then the effects of the ratios are analyzed respectively on the average stress amplitudes, the standard deviations of the stress amplitudes, and the stress amplitudes under different survival probabilities and confidences. The results reveal that the ratios act a relatively decreasing effect to the stress amplitudes under higher survival probabilities and confidences. The strongest effect appears at the ratio of 0.029, and a weaker effect acts as the distance increase of the ratio from the zero. In addition, it is indicated that the effects from the sense of average fatigue lives might result in a wrong conclusion. The effects can be appropriately assessed from a probabilistic sense to take into account the scattering regularity of test data and the size of sampling. (author)

  17. Decoupling Strain and Ligand Effects in Ternary Nanoparticles for Improved ORR Electrocatalysis

    DEFF Research Database (Denmark)

    C. Jennings, Paul; Lysgaard, Steen; Hansen, Heine Anton

    2016-01-01

    shows the effect of the ternary metal core allowing for tuning the catalytic activity through strain effects. Good agreement is found with experimental studies showing increased activity of Pt-Au-Fe/Ni nanoparticles, and the current study suggests that mid to late 3d-metals should also exhibit enhance...

  18. The effect of dynamic aging on the strain hardening rate of titanium

    International Nuclear Information System (INIS)

    Monteiro, S.N.; Reed-Hill, R.E.

    1974-01-01

    A study is made of the effect due to the interaction of solute atoms with mobile dislo cations, known as dynamic aging on the strain hardening characteristics of titanium between 150 and 477K. The results obtained with commercially pure titanium are compared with those obtained using high - purity titanium in order to evaluate the extent of effect [pt

  19. ADP-Induced Ca2+Signaling and Proliferation of Rat Ventricular Myofibroblasts Depend on Phospholipase C-Linked TRP Channels Activation Within Lipid Rafts.

    Science.gov (United States)

    Certal, Mariana; Vinhas, Adriana; Barros-Barbosa, Aurora; Ferreirinha, Fátima; Costa, Maria Adelina; Correia-de-Sá, Paulo

    2017-06-01

    Nucleotides released during heart injury affect myocardium electrophysiology and remodeling through P2 purinoceptors activation in cardiac myofibroblasts. ATP and UTP endorse [Ca 2+ ] i accumulation and growth of DDR-2/α-SMA-expressing myofibroblasts from adult rat ventricles via P2Y 4 and P2Y 2 receptors activation, respectively. Ventricular myofibroblasts also express ADP-sensitive P2Y 1 , P2Y 12 , and P2Y 13 receptors as demonstrated by immunofluorescence confocal microscopy and western blot analysis, but little information exists on ADP effects in these cells. ADP (0.003-3 mM) and its stable analogue, ADPßS (100 μM), caused fast [Ca 2+ ] i transients originated from thapsigargin-sensitive internal stores, which partially declined to a plateau sustained by capacitative Ca 2+ entry through transient receptor potential (TRP) channels inhibited by 2-APB (50 μM) and flufenamic acid (100 μM). Hydrophobic interactions between G q/11 -coupled P2Y purinoceptors and TRP channels were suggested by prevention of the ADP-induced [Ca 2+ ] i plateau following PIP 2 depletion with LiCl (10 mM) and cholesterol removal from lipid rafts with methyl-ß-cyclodextrin (2 mM). ADP [Ca 2+ ] i transients were insensitive to P2Y 1 , P2Y 12 , and P2Y 13 receptor antagonists, MRS2179 (10μM), AR-C66096 (0.1 μM), and MRS2211 (10μM), respectively, but were attenuated by suramin and reactive blue-2 (100 μM) which also blocked P2Y 4 receptors activation by UTP. Cardiac myofibroblasts growth and type I collagen production were favored upon activation of MRS2179-sensitive P2Y 1 receptors with ADP or ADPßS (30 μM). In conclusion, ADP exerts a dual role on ventricular myofibroblasts: [Ca 2+ ] i transients are mediated by fast-desensitizing P2Y 4 receptors, whereas the pro-fibrotic effect of ADP involves the P2Y 1 receptor activation. Data also show that ADP-induced capacitative Ca 2+ influx depends on phospholipase C-linked TRP channels opening in lipid raft

  20. Effects of hole doping and strain on magnetism in buckled phosphorene and arsenene

    Science.gov (United States)

    Fu, Botao; Feng, Wanxiang; Zhou, Xiaodong; Yao, Yugui

    2017-06-01

    Phosphorene and arsenene are newly discovered two-dimensional semiconductors with many exciting physical properties. Here, using first-principles density functional theory, we investigate the effects of hole doping and strain on the magnetism in phosphorene and arsenene with buckled structures. We show that ferromagnetic ground states originating from Stoner instability can emerge in a broad range of hole concentrations. In addition, strain effectively modulates the magnetism by means of changing the band orders of the top of the valence bands. Magnetoresponses under hole doping and strain in buckled phosphorene and arsenene are distinct due to the contrary band orders at their native states. Furthermore, magnetoelastic coupling effect and magnetostriction in buckled phosphorene and arsenene are discussed. Our results suggest the great potential of buckled phosphorene and arsenene in magnetic device applications.

  1. UV inactivation: Combined effects of UV radiation and xenobiotics in two strains of Saccharomyces

    International Nuclear Information System (INIS)

    Lochmann, E.R.; Lochmann, G.

    1997-01-01

    The effects of eight chemicals on the inactivation rate of ultraviolet radiation on the colony building capabilities of two strains of Saccharomyces cervisae - a wild type strain and a mutant deficient in excision repair - were studied. The insecticide methoxychlor, the herbicide 2,4-dichlorophenoxyacetic acid, the fungicide pentachlorophenol and its metabolite tetrachlorohydroquinone, as well as the chemicals acrylonitrile and 2,3-dichloro-1-propene have no significant impact on the effects of UV radiation in Saccharomyces cerevisae. Depending on the concentration, trichloroethylene increases the sensitivity to UV radiation. The herbicide paraquat provides efficient protection against UV radiation at concentrations where a toxic effect cannot be observed even without UV. The results were rather similar for both strains. (orig.) [de

  2. Soft-tissue material properties under large deformation: strain rate effect.

    Science.gov (United States)

    Hu, Tie; Desai, Jaydev P

    2004-01-01

    Biomechanical model of soft tissue derived from experimental measurements is critical for developing a reality-based model for minimally invasive surgical training and simulation. In our research, we have focused on developing a biomechanical model of the liver with the ultimate goal of using this model for local tool-tissue interaction tasks and providing feedback to the surgeon through a haptic display. We are interested in finding the local effective elastic modulus (LEM) of the liver tissue under different strain rates. We have developed a tissue indentation equipment for characterizing the biomechanical properties of the liver and compared the local effective elastic modulus (LEM) derived from experimental data with plane stress, plane strain, and axisymmetric element types in ABAQUS under varying strain rates. Our results show that the experimentally derived local effective modulus matches closely with the plane stress analysis in ABAQUS.

  3. Different effects of BCG strains - A natural experiment evaluating the impact of the Danish and the Russian BCG strains on morbidity and scar formation in Guinea-Bissau.

    Science.gov (United States)

    Frankel, H; Byberg, S; Bjerregaard-Andersen, M; Martins, C L; Aaby, P; Benn, C S; Fisker, A B

    2016-08-31

    Different Bacillus Calmette-Guerin (BCG) vaccine strains may have different non-specific effects. We assessed the effect of two BCG strains (Danish and Russian) on childhood morbidity and BCG scarification in Guinea-Bissau. During 2011-2013, infants in the Bandim Health Project's urban study area received the Danish or Russian BCG in a natural experiment. Health center consultations were registered at point of care and scar status and size at age 4½ months. We assessed the effect of strain on consultation rates between vaccination and age 45days in Cox proportional hazards models. Scar prevalence and size were compared using binomial regression and ranksum tests. Among 1206 children, 18% received Danish BCG (n=215) and 82% Russian BCG (n=991). The adjusted hazard ratio (aHR) for consultations was 0.94 (95% CI 0.60-1.46) for Danish BCG compared with Russian BCG. Girls vaccinated with Danish BCG tended to have lower consultation rates compared with girls vaccinated with Russian BCG (aHR 0.56 (0.25-1.24)), whereas the effect was opposite for boys (aHR 1.24 (0.74-2.11)), p=0.09. Children vaccinated with Danish BCG were more likely to develop a scar (97%) than children vaccinated with Russian BCG (87%), the relative risk (RR) being 1.11 (1.06-1.16). The effect was stronger in girls, and BCG scar size was larger among infants vaccinated with the Danish strain. BCG strain influences scar prevalence and scar size, and may have sex differential effects on morbidity. BCG strains are currently used interchangeably, but BCG scarring has been linked to subsequent survival. Hence, more research into the health effects of different BCG strains is warranted. Small adjustments of BCG production could potentially lower childhood morbidity and mortality at low cost. Copyright © 2016 Elsevier Ltd. All rights reserved.

  4. Mechanical properties and strain effects in superconductors: Metallurgy, fabrication, and applications

    International Nuclear Information System (INIS)

    Ekin, J.W.

    1981-01-01

    This paper studies the mechanical properties and material strain effects for magnet design in superconductors. The material strain limit for typical magnet systems such as multifilamentary Nb 3 Sn, Nb 3 Sn dipoles plus small bore, pulsed NbTi:Cu, epoxy impregnated, and large SS reinforced are given, along with the limiting property, and the material limit. For each magnet type, a different mechanical property and material play the limiting role: In multifilamentary Nb 3 Sn magnets, uniaxial-strain degradation of I /SUB c/ is the limiting factor. If, in addition, the Nb 3 Sn magnet is a dipole or small bore magnet, the tight bend radius required of the conductor sets bending strain limits on the conductor thickness. In pulsed NbTi:copper magnets that will be cycled many times without anneal, fatigue degradation of the stabilizing copper matrix is the primary factor placing limits on the peak-to-peak strain amplitude. In high-current density, epoxy-impregnated magnets, excessive training caused by the low strain tolerance of epoxies at cryogenic temperatures generally plays the primary role. Finally, in large reinforced magnets, the yield properties of the structural reinforcement material set the mechanical design limits

  5. Spin-dependent delay time and Hartman effect in asymmetrical graphene barrier under strain

    Science.gov (United States)

    Sattari, Farhad; Mirershadi, Soghra

    2018-01-01

    We study the spin-dependent tunneling time, including group delay and dwell time, in a graphene based asymmetrical barrier with Rashba spin-orbit interaction in the presence of strain, sandwiched between two normal leads. We find that the spin-dependent tunneling time can be efficiently tuned by the barrier width, and the bias voltage. Moreover, for the zigzag direction strain although the oscillation period of the dwell time does not change, the oscillation amplitude increases by increasing the incident electron angle. It is found that for the armchair direction strain unlike the zigzag direction the group delay time at the normal incidence depends on the spin state of electrons and Hartman effect can be observed. In addition, for the armchair direction strain the spin polarization increases with increasing the RSOI strength and the bias voltage. The magnitude and sign of spin polarization can be manipulated by strain. In particular, by applying an external electric field the efficiency of the spin polarization is improved significantly in strained graphene, and a fully spin-polarized current is generated.

  6. Study of strain-modulated effects on CoFe2O4 epitaxial films

    Science.gov (United States)

    Chen, Yi-Chun; Liou, Yi-De; Wu, Kun-Hong; Wang, Chih-Kuo; Chu, Ying-Hao

    Due to the improvement of thin film growth technique, epitaxial films directly grown on flexible substrates became possible recently. These kinds of flexible systems not only have the advantage of easy integration for device applications, but also provide a template to purify strain effects for physical mechanism study. Here, we investigate the evolution of the spinel CoFe2O4 (CFO) epitaxial film on a muscovite substrate with variable curvatures. CFO possesses superior magnetic properties with high Curie temperature and large magnetostrictive anisotropy. The CFO film on muscovite is (111) oriented, corresponding to a magnetic hard-axis along the out-of-plane direction. Under the in-plane asymmetric strain, based on the frequency shift of Raman A1g phonon, the unit cell volume of CFO increases with the tensile strain while decreases with the compressive strain. The tunable volume ratio is about 0.7 %. The A1g and T2g phonon evolutions also show the Co/Fe cation migration temperature decreases both under tensile and compressive strain with the degradation up to 40 K. Moreover, when out-of-plane magnetic field is applied, the magnetostriction constant increases with the compressive strain, which implies the tunable orientation of magnetic easy axis in this flexible system.

  7. Effect of strain rate and dislocation density on the twinning behavior in tantalum

    Energy Technology Data Exchange (ETDEWEB)

    Florando, Jeffrey N., E-mail: florando1@llnl.gov; Swift, Damian C.; Barton, Nathan R.; McNaney, James M.; Kumar, Mukul [Lawrence Livermore National Laboratory, 7000 East Ave., Livermore, CA 94550 (United States); El-Dasher, Bassem S. [TerraPower LLC, Bellevue, WA 98005 (United States); Chen, Changqiang [Materials Research Laboratory, University of Illinois at Urbana Champaign, Urbana, IL 61801 (United States); Ramesh, K. T.; Hemker, Kevin J. [Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD 21218 (United States)

    2016-04-15

    The conditions which affect twinning in tantalum have been investigated across a range of strain rates and initial dislocation densities. Tantalum samples were subjected to a range of strain rates, from 10{sup −4}/s to 10{sup 3}/s under uniaxial stress conditions, and under laser-induced shock-loading conditions. In this study, twinning was observed at 77 K at strain rates from 1/s to 10{sup 3}/s, and during laser-induced shock experiments. The effect of the initial dislocation density, which was imparted by deforming the material to different amounts of pre-strain, was also studied, and it was shown that twinning is suppressed after a given amount of pre-strain, even as the global stress continues to increase. These results indicate that the conditions for twinning cannot be represented solely by a critical global stress value, but are also dependent on the evolution of the dislocation density. In addition, the analysis shows that if twinning is initiated, the nucleated twins may continue to grow as a function of strain, even as the dislocation density continues to increase.

  8. Thickness-Dependent Strain Effect on the Deformation of the Graphene-Encapsulated Au Nanoparticles

    Directory of Open Access Journals (Sweden)

    Shuangli Ye

    2014-01-01

    Full Text Available The strain effect on graphene-encapsulated Au nanoparticles is investigated. A finite-element calculation is performed to simulate the strain distribution and morphology of the monolayer and multilayer graphene-encapsulated Au nanoparticles, respectively. It can be found that the inhomogeneous strain and deformation are enhanced with the increasing shrinkage of the graphene shell. Moreover, the strain distribution and deformation are very sensitive to the layer number of the graphene shell. Especially, the inhomogeneous strain at the interface between the graphene shell and encapsulated Au nanoparticles is strongly tuned by the graphene thickness. For the mono- and bilayer graphene-encapsulated Au nanoparticles, the dramatic shape transformation can be observed. However, with increasing the graphene thickness further, there is hardly deformation for the encapsulated Au nanoparticles. These simulated results indicate that the strain and deformation can be designed by the graphene layer thickness, which provides an opportunity to engineer the structure and morphology of the graphene-encapsulated nanoparticles.

  9. Effect of the Strain Rate on the Tensile Properties of the AZ31 Magnesium Alloy

    International Nuclear Information System (INIS)

    Jeong, Seunghun; Park, Jiyoun; Choi, Ildong; Park, Sung Hyuk

    2013-01-01

    The effect of the strain rate at a range of 10‒4 ⁓ 3 × 10 2 s - 1 on the tensile characteristics of a rolled AZ31 magnesium alloy was studied. The normal tensile specimens were tested using a high rate hydraulic testing machine. Specimens were machined from four sheets with different thicknesses, 1, 1.5, 2 and 3 mm, along three directions, 0°, 45°, and 90° to the rolling direction. The results revealed that all the specimens had a positive strain rate sensitivity of strength, that is, the strength increased with increasing strain rate. This is the same tendency as other automotive steels have. Our results suggest that the AZ31 magnesium alloy has better collision characteristics at high strain rates because of improved strength with an increasing strain rate. Ductility decreased with an increasing strain rate with a strain rate under 1 s - 1, but it increased with an increasing strain rate over 1 s - 1. The mechanical properties of the AZ31 magnesium alloy depend on the different microstructures according to the thickness. Two and 3 mm thickness specimens with a coarse and non-uniform grain structure exhibited worse mechanical properties while the 1.5 mm thickness specimens with a fine and uniform grain structure had better mechanical properties. Specimens machined at 0° and 45° to the rolling direction had higher absorbed energy than that of the 90° specimen. Thus, we demonstrate it is necessary to choose materials with proper thickness and machining direction for use in automotive applications.

  10. The effect of distal ulnar implant stem material and length on bone strains.

    Science.gov (United States)

    Austman, Rebecca L; Beaton, Brendon J B; Quenneville, Cheryl E; King, Graham J W; Gordon, Karen D; Dunning, Cynthia E

    2007-01-01

    Implant design parameters can greatly affect load transfer from the implant stem to the bone. We have investigated the effect of length or material of distal ulnar implant stems on the surrounding bone strains. Eight cadaveric ulnas were instrumented with 12 strain gauges and secured in a customized jig. Strain data were collected while loads (5-30 N) were applied to the medial surface of the native ulnar head. The native ulnar head was removed, and a stainless steel implant with an 8-cm-long finely threaded stem was cemented into the canal. After the cement had cured, the 8-cm stem was removed, leaving a threaded cement mantle in the canal that could accept shorter threaded stems of interest. The loading protocol was then repeated for stainless steel stems that were 7, 5, and 3 cm in length, as well as for a 5-cm-long titanium alloy (TiAl(6)V(4)) stem. Other stainless steel stem lengths between 3 and 7 cm were tested at intervals of 0.5 cm, with only a 20 N load applied. No stem length tested matched the native strains at all gauge locations. No significant differences were found between any stem length and the native bone at the 5th and 6th strain gauge positions. Strains were consistently closer to the native bone strains with the titanium stem than the stainless steel stem for each gauge pair that was positioned on the bone overlying the stem. The 3-cm stem results were closer to the native strains than the 7-cm stem for all loads at gauges locations that were on top of the stem. The results from this study suggest that the optimal stem characteristics for distal ulnar implants from a load transfer point of view are possessed by shorter (approximately 3 to 4 cm) titanium stems.

  11. EFFECTS OF MICROELEMENTS ON THE CAROTENOID SYNTHESIS BY SOME BASIDIOMYCETES STRAINS

    Directory of Open Access Journals (Sweden)

    A. K. Velygodska

    2016-08-01

    Full Text Available The effect of microelements on growth and accumulation of carotenoids highly productive strains of basidiomycetes at surface cultivation on glucose-peptone medium was investigated. The objects of research are 3 wood destroying strain. There are Laetiporus sulphureus (Bull. Murrill Ls-08, Fomes fomentarius (L. Fr. Ff-1201 from the order Polyporales and Fistulina hepatica (Schaeff. Sibth Fh-18 from the order Agaricales. Research materials are strains mycelium and culture filtrate (CF. Absolutely dry biomass (ADB mycelium was determined by the gravimetric method, the content of carotenoids was determined by spectrophotometric method in acetone extracts of the Vetshteyn formula. Established individual influence of microelements on the accumulation of biomass and carotenoids of basidiomycetes strains. The possibility of the regulation of these processes by introducing into the glucose-peptone medium of various Fe, Cu, Zn, Ni and Mn sulphate. So, the best to increase the intensity of the growth processes and the accumulation of carotenoids strain of L. sulphureus Ls-08 is an experimental environment which includes Zn sulfate in a concentration of 8 mmol/L. To induce the accumulation of ADB and carotenoids in the mycelium and CF of strain F fomentarius Ff-1201 making in is expedient Mn sulfate in a concentration of 1.6 mmol/L. To improve carotenogenesis of F. hepatica Fh-18 strain expedient entry in GPM Mn sulphate at concentration of 8 mmol/L. These allow to optimize the concentration of microelements in nutrient medium for the cultivation of carotenoids high-producing strains of Basidiomycetes.

  12. Effect of Restorative Protocol on Cuspal Strain and Residual Stress in Endodontically Treated Molars.

    Science.gov (United States)

    Pereira, Ras; Bicalho, A A; Franco, S D; Tantbirojn, D; Versluis, A; Soares, C J

    2016-01-01

    To evaluate the effect of the restorative protocol on cuspal strain, fracture resistance, residual stress, and mechanical properties of restorative materials in endodontically treated molars. Forty-five molars received mesio-occlusal-distal (MOD) Class II preparations and endodontic treatment followed by direct restorations using three restorative protocols: composite resin (CR) only (Filtek Supreme, 3M-ESPE), resin modified glass ionomer cement in combination with CR (Vitremer, 3M-ESPE in pulp chamber and Filtek Supreme in MOD cavity), conventional glass ionomer cement in combination with composite resin (CGI-CR) (Ketac Fil, 3M-ESPE in pulp chamber and Filtek Supreme in MOD cavity). Cuspal strain was measured using strain gauges, and fracture resistance was tested with an occlusal load. Elastic modulus (EM) and Vickers hardness (VH) of the restorative materials were determined at different depths using dynamic microhardness indentation. Curing shrinkage was measured using the strain gauge technique. The restorative protocols were also simulated in finite element analysis (FEA). The shrinkage strain, cuspal strain, EM, VH, and fracture resistance data were statistically analyzed using split-plot analysis of variance and Tukey test (p=0.05). Residual shrinkage stresses were expressed in modified von Mises equivalent stresses. Shrinkage strain values (in volume %) were Ketac Fil (0.08±0.01) restorative protocol significantly affected the biomechanical behavior of endodontically treated molars. Using glass ionomer to fill the pulp chamber is recommended when endodontically treated molars receive direct composite restorations because it reduces cuspal strain and increases fracture resistance.

  13. The effect of the shoe-surface interface in the development of anterior cruciate ligament strain.

    Science.gov (United States)

    Drakos, Mark C; Hillstrom, Howard; Voos, James E; Miller, Anna N; Kraszewski, Andrew P; Wickiewicz, Thomas L; Warren, Russell F; Allen, Answorth A; O'Brien, Stephen J

    2010-01-01

    The shoe-surface interface has been implicated as a possible risk factor for anterior cruciate ligament (ACL) injuries. The purpose of this study is to develop a biomechanical, cadaveric model to evaluate the effect of various shoe-surface interfaces on ACL strain. There will be a significant difference in ACL strain between different shoe-surface combinations when a standardized rotational moment (a simulated cutting movement) is applied to an axially loaded lower extremity. The study design was a controlled laboratory study. Eight fresh-frozen cadaveric lower extremities were thawed and the femurs were potted with the knee in 30 deg of flexion. Each specimen was placed in a custom-made testing apparatus, which allowed axial loading and tibial rotation but prevented femoral rotation. For each specimen, a 500 N axial load and a 1.5 Nm internal rotation moment were placed for four different shoe-surface combinations: group I (AstroTurf-turf shoes), group II (modern playing turf-turf shoes), group III (modern playing turf-cleats), and group IV (natural grass-cleats). Maximum strain, initial axial force and moment, and maximum axial force and moment were calculated by a strain gauge and a six component force plate. The preliminary trials confirmed a linear relationship between strain and both the moment and the axial force for our testing configuration. In the experimental trials, the average maximum strain was 3.90, 3.19, 3.14, and 2.16 for groups I-IV, respectively. Group IV had significantly less maximum strain (pcleat combination produced less strain in the ACL than the other combinations. The favorable biomechanical properties of the cleat-grass interface may result in fewer noncontact ACL injuries.

  14. Effect of Experience and Training on the Concordance and Precision of Strain Measurements.

    Science.gov (United States)

    Negishi, Tomoko; Negishi, Kazuaki; Thavendiranathan, Paaladinesh; Cho, Goo-Yeong; Popescu, Bogdan A; Vinereanu, Dragos; Kurosawa, Koji; Penicka, Martin; Marwick, Thomas H

    2017-05-01

    This study sought to show the degree to which experience and training affect the precision and validity of global longitudinal strain (GLS) measurement and to evaluate the variability of strain measurement after feedback. The application of GLS for the detection of subclinical dysfunction has been recommended in an expert consensus document and is being used with increasing frequency. The role of experience in the precision and validity of GLS measurement is unknown, as is the efficacy of training. Fifty-eight readers, divided into 4 groups on the basis of their experience with GLS, calculated GLS from speckle strain analysis of 9 cases with various degrees of image quality. Intraclass correlation coefficients (ICCs), mean difference, SD, and coefficient of variation (CV) were compared against the measurements of a reference group that had experience with >1,000 cases of strain measurement. Individualized feedback was distributed, and repeat measurements were performed by 40 readers. Comparisons with the baseline variation provided information about whether feedback was effective. The ICC for GLS was significantly greater than that for ejection fraction regardless of image quality. Experience with strain measurement affected the concordance in strain values among the readers; the group with the highest level of experience showed significantly better ICC than those with no experience, although the ICC of the inexperienced readers was still very good (0.996 vs. 0.975; p = 0.0002). As experience increased, the mean difference, SD, and CV became significantly smaller. The CV of segmental strain analysis showed significant improvement after training, regardless of experience. The favorable interobserver agreement of GLS makes it more attractive than ejection fraction for follow-up of left ventricular function by multiple observers. Although experience is important, the precision of GLS was high for all groups. Training appears to be of most value for the assessment of

  15. Intermittent parathyroid hormone (PTH) promotes cementogenesis and alleviates the catabolic effects of mechanical strain in cementoblasts.

    Science.gov (United States)

    Li, Yuyu; Hu, Zhiai; Zhou, Chenchen; Xu, Yang; Huang, Li; Wang, Xin; Zou, Shujuan

    2017-04-20

    External root resorption, commonly starting from cementum, is a severe side effect of orthodontic treatment. In this pathological process and repairing course followed, cementoblasts play a significant role. Previous studies implicated that parathyroid hormone (PTH) could act on committed osteoblast precursors to promote differentiation, and inhibit apoptosis. But little was known about the role of PTH in cementoblasts. The purpose of this study was to investigate the effects of intermittent PTH on cementoblasts and its influence after mechanical strain treatment. Higher levels of cementogenesis- and differentiation-related biomarkers (bone sialoprotein (BSP), osteocalcin (OCN), Collagen type I (COL1) and Osterix (Osx)) were shown in 1-3 cycles of intermittent PTH treated groups than the control group. Additionally, intermittent PTH increased alkaline phosphatase (ALP) activity and mineralized nodules formation, as measured by ALP staining, quantitative ALP assay, Alizarin red S staining and quantitative calcium assay. The morphology of OCCM-30 cells changed after mechanical strain exertion. Expression of BSP, ALP, OCN, osteopontin (OPN) and Osx was restrained after 18 h mechanical strain. Furthermore, intermittent PTH significantly increased the expression of cementogenesis- and differentiation-related biomarkers in mechanical strain treated OCCM-30 cells. Taken together, these data suggested that intermittent PTH promoted cementum formation through activating cementogenesis- and differentiation-related biomarkers, and attenuated the catabolic effects of mechanical strain in immortalized cementoblasts OCCM-30.

  16. ADP-ribosylation of transducin by pertussis toxin

    International Nuclear Information System (INIS)

    Watkins, P.A.; Burns, D.L.; Kanaho, Y.; Liu, T.Y.; Hewlett, E.L.; Moss, J.

    1985-01-01

    Transducin, the guanyl nucleotide-binding regulatory protein of retinal rod outer segments that couples the photon receptor, rhodopsin, with the light-activated cGMP phosphodiesterase, can be resolved into two functional components, T alpha and T beta gamma. T alpha (39 kDa), which is [ 32 P]ADP-ribosylated by pertussis toxin and [ 32 P]NAD in rod outer segments and in purified transducin, was also labeled by the toxin after separation from T beta gamma (36 kDa and approximately 10 kDa); neither component of T beta gamma was a pertussis toxin substrate. Labeling of T alpha was enhanced by T beta gamma and was maximal at approximately 1:1 molar ratio of T alpha : T beta gamma. Limited proteolysis by trypsin of T alpha in the presence of guanyl-5'-yl imidodiphosphate (Gpp(NH)p) resulted in the sequential appearance of proteins of 38 and 32 kDa. The amino terminus of both 38- and 32 -kDa proteins was leucine, whereas that of T alpha could not be identified and was assumed to be blocked. The 32 -kDa peptide was not a pertussis toxin substrate. Labeling of the 38-kDa protein was poor and was not enhanced by T beta gamma. Trypsin treatment of [ 32 P]ADP-ribosyl-T alpha produced a labeled 37-38-kDa doublet followed by appearance of radioactivity at the dye front. It appears, therefore, that, although the 38-kDa protein was poor toxin substrate, it contained the ADP-ribosylation site. Without rhodopsin, labeling of T alpha (in the presence of T beta gamma) was unaffected by Gpp(NH)p, guanosine 5'-O-(thiotriphosphate) (GTP gamma S), GTP, GDP, and guanosine 5'-O-(thiodiphosphate) (GDP beta S) but was increased by ATP. When photolyzed rhodopsin and T beta gamma were present, Gpp(NH)p and GTP gamma S decreased [ 32 P]ADP-ribosylation by pertussis toxin. Thus, pertussis toxin-catalyzed [ 32 P]ADP-ribosylation of T alpha was affected by nucleotides, rhodopsin and light in addition to T beta gamma

  17.  Poly(ADP-ribose polymerase (PARP inhibitors in BRCA1/2 cancer therapy

    Directory of Open Access Journals (Sweden)

    Katarzyna Kluzek

    2012-06-01

    Full Text Available  A majority of currently used anticancer drugs belong to a group of chemical agents that damage DNA. The efficiency of the treatment is limited by effective DNA repair systems functioning in cancer cells. Many chemotherapeutic compounds cause strong systemic toxicity. Therefore, there is still a need for new anticancer agents which are less toxic for nontransformed cells and selectively kill cancer cells. One of the most promising molecular targets in cancer therapy is poly(ADP-ribose polymerases (PARP. PARP play an essential role in repairing DNA strand breaks. Small molecule inhibitors of these enzymes have been developed and have proved to be extremely toxic for cancer cells that lack the functional BRCA1 and BRCA2 proteins that are involved in homologous recombination, a complex repair mechanism of DNA double strand breaks. Mutations in BRCA1/2 genes are associated with genetically inherited breast and ovarian cancers. Therefore PARP inhibitors may prove to be very effective and selective in the treatment of these cancer types. This review is focused on the function of BRCA1/2 proteins and poly(ADP-ribose polymerases in DNA repair systems, especially in the homologous recombination process. A short history of the studies that led to synthesis of high specificity small molecule PARP inhibitors is also presented, as well as the results of clinical trials concerning the most effective PARP inhibitors in view of their potential application in oncological treatment, particularly breast cancers.

  18. Submaximal ADP-stimulated respiration is impaired in ZDF rats and recovered by resveratrol.

    Science.gov (United States)

    Smith, Brennan K; Perry, Christopher G R; Herbst, Eric A F; Ritchie, Ian R; Beaudoin, Marie-Soleil; Smith, Jeffrey C; Neufer, P Darrell; Wright, David C; Holloway, Graham P

    2013-12-01

    Mitochondrial dysfunction and reactive oxygen species (ROS) have been implicated in the aetiology of skeletal muscle insulin resistance, although there is considerable controversy regarding these concepts. Mitochondrial function has been traditionally assessed in the presence of saturating ADP, but ATP turnover and the resultant ADP is thought to limit respiration in vivo. Therefore, we investigated the potential link between submaximal ADP-stimulated respiration rates, ROS generation and skeletal muscle insulin sensitivity in a model of type 2 diabetes mellitus, the ZDF rat. Utilizing permeabilized muscle fibres we observed that submaximal ADP-stimulated respiration rates (250-2000 μm ADP) were lower in ZDF rats than in lean controls, which coincided with decreased adenine nucleotide translocase 2 (ANT2) protein content. This decrease in submaximal ADP-stimulated respiration occurred in the absence of a decrease in electron transport chain function. Treating ZDF rats with resveratrol improved skeletal muscle insulin resistance and this was associated with elevated submaximal ADP-stimulated respiration rates as well as an increase in ANT2 protein content. These results coincided with a greater ability of ADP to attenuate mitochondrial ROS emission and an improvement in cellular redox balance. Together, these data suggest that mitochondrial dysfunction is present in skeletal muscle insulin resistance when assessed at submaximal ADP concentrations and that ADP dynamics may influence skeletal muscle insulin sensitivity through alterations in the propensity for mitochondrial ROS emission.

  19. A role of intracellular mono-ADP-ribosylation in cancer biology.

    Science.gov (United States)

    Scarpa, Emanuele S; Fabrizio, Gaia; Di Girolamo, Maria

    2013-08-01

    During the development, progression and dissemination of neoplastic lesions, cancer cells can hijack normal pathways and mechanisms. This includes the control of the function of cellular proteins through reversible post-translational modifications, such as ADP-ribosylation, phosphorylation, and acetylation. In the case of mono-ADP-ribosylation and poly-ADP-ribosylation, the addition of one or several units of ADP-ribose to target proteins occurs via two families of enzymes that can generate ADP-ribosylated proteins: the diphtheria toxin-like ADP-ribosyltransferase (ARTD) family, comprising 17 different proteins that are either poly-ADP-ribosyltransferases or mono-ADP-ribosyltransferases or inactive enzymes; and the clostridial toxin-like ADP-ribosyltransferase family, with four human members, two of which are active mono-ADP-ribosyltransferases, and two of which are enzymatically inactive. In line with a central role for poly-ADP-ribose polymerase 1 in response to DNA damage, specific inhibitors of this enzyme have been developed as anticancer therapeutics and evaluated in several clinical trials. Recently, in combination with the discovery of a large number of enzymes that can catalyse mono-ADP-ribosylation, the role of this modification has been linked to human diseases, such as inflammation, diabetes, neurodegeneration, and cancer, thus revealing the need for the development of specific ARTD inhibitors. This will provide a better understanding of the roles of these enzymes in human physiology and pathology, so that they can be targeted in the future to generate new and efficacious drugs. This review summarizes our present knowledge of the ARTD enzymes that are involved in mono-ADP-ribosylation reactions and that have roles in cancer biology. In particular, the well-documented role of macro-containing ARTD8 in lymphoma and the putative role of ARTD15 in cancer are discussed. © 2013 The Authors Journal compilation © 2013 FEBS.

  20. Effect of ratchet strain on fatigue and creep–fatigue strength of Mod.9Cr–1Mo steel

    International Nuclear Information System (INIS)

    Ando, Masanori; Isobe, Nobuhiro; Kikuchi, Koichi; Enuma, Yasuhiro

    2012-01-01

    Highlights: ► Uniaxial fatigue and creep–fatigue tests with superimposed strain were performed. ► Variety of superimposed strain were applied as ratchet strain in the tests. ► Effect of superimposed strain on fatigue and creep–fatigue life is negligible. ► A cyclic softening character reducing the effect of superimposed strain. - Abstract: The effect of ratcheting deformation on fatigue and creep–fatigue life in Mod.9Cr–1Mo steel was investigated. Uniaxial fatigue and creep–fatigue testing with superimposed strain were performed to evaluate the effect of ratcheting deformation on the failure cycle. In a series of tests, a specific amount of superimposed strain was accumulated in each cycle. The accumulated strain as ratcheting deformation, cycles to reach the accumulated strain, and test temperatures were varied in the tests. In the fatigue tests with superimposed strain at 550 °C, slight reductions of failure lives were observed. All of the numbers of cycles to failure in the fatigue tests with superimposed strain were within a factor of 1.5 of that of the fatigue test without superimposed strain at 550 °C. The apparent relationship between failure cycles and testing parameters was not observed. In fatigue tests with superimposed strain at 550 °C, maximum mean stress was insignificant and generated in early cycles because Mod.9Cr–1Mo steel exhibits cyclic softening characteristics. It was assumed that suppression of mean stress generation by cyclic softening reduces the effect of ratcheting strain. Conversely, failure lives were increased by accumulated strain in the test conducted at 450 °C because of stress–strain hysteresis loop shrinkage caused by cyclic softening induced by the accumulated strain. In the creep–fatigue tests with superimposed strain, test results indicated that the accumulated stain was negligible. It was concluded that the effect of ratcheting deformation on fatigue and creep–fatigue life is negligible as long

  1. Effects of Bacillus thuringiensis strains virulent to Varroa destructor on larvae and adults of Apis mellifera.

    Science.gov (United States)

    Alquisira-Ramírez, Eva Vianey; Peña-Chora, Guadalupe; Hernández-Velázquez, Víctor Manuel; Alvear-García, Andrés; Arenas-Sosa, Iván; Suarez-Rodríguez, Ramón

    2017-08-01

    The sublethal effects of two strains of Bacillus thuringiensis, which were virulent in vitro to Varroa destructor, were measured on Apis mellifera. The effects of five concentrations of total protein (1, 5, 25, 50 and 100μg/mL) from the EA3 and EA26.1 strains on larval and adult honey bees were evaluated for two and seven days under laboratory conditions. Based on the concentrations evaluated, total protein from the two strains did not affect the development of larvae, the syrup consumption, locomotor activity or proboscis extension response of adults. These same parameters were also tested for the effects of three concentrations (1, 10 and 15μg/kg) of cypermethrin as a positive control. Although no significant differences were observed after two days of treatment with cypermethrin, a dose-response relationship in syrup consumption and locomotor activity was observed. A significant reduction in the proboscis extension response of the bees treated with cypermethrin was also observed. Therefore, in contrast to cypermethrin, our results indicate that the EA3 and EA26.1 strains of B. thuringiensis can be used in beehives to control V. destructor and reduce the negative effects of this mite on colonies without adverse effects on the larvae and adults of A. mellifera. Additionally, the overuse of synthetic miticides, which produce both lethal and sublethal effects on bees, can be reduced. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Strain-dependent Effects of Acute, Chronic, and Withdrawal from Chronic Nicotine on Fear Conditioning

    Science.gov (United States)

    Portugal, George S.; Wilkinson, Derek S.; Kenney, Justin W.; Sullivan, Colleen

    2013-01-01

    The effects of nicotine on cognitive processes such as learning and memory may play an important role in the addictive liability of tobacco. However, it remains unknown whether genetic variability modulates the effects of nicotine on learning and memory. The present study characterized the effects of acute, chronic, and withdrawal from chronic nicotine administration on fear conditioning, somatic signs, and the elevated plus maze in 8 strains of inbred mice. Strain-dependent effects of acute nicotine and nicotine withdrawal on contextual fear conditioning, somatic signs, and the elevated plus maze were observed, but no association between the effects of acute nicotine and nicotine withdrawal on contextual fear conditioning were observed, suggesting that different genetic substrates may mediate these effects. The identification of genetic factors that may alter the effects of nicotine on cognition may lead to more efficacious treatments for nicotine addiction. PMID:21822688

  3. Effects of pesticides on plant growth promoting traits of Mesorhizobium strain MRC4

    Directory of Open Access Journals (Sweden)

    Munees Ahemad

    2012-01-01

    Full Text Available The objective of this study was to assess the effect of selected pesticides [herbicides (metribuzin and glyphosate, insecticides (imidacloprid and thiamethoxam and fungicides (hexaconazole, metalaxyl and kitazin] at recommended and higher dose rates on plant growth promoting activities of the Mesorhizobium sp. isolated from chickpea-nodules. A total of 50 rhizobial strains recovered from the nodules of chickpea root systems were identified following morphological, biochemical and host-specificity tests and tested for pesticide-tolerance. Among these strains, the Mesorhizobium sp. strain MRC4 was specifically selected due to the highest tolerance levels for all selected pesticides and the maximum production of plant growth promoting substances. Strain MRC4 produced indole acetic acid (44 μg ml−1, siderophores [salicylic acid (35 μg ml−1 and 2,3-dihydroxy benzoic acid (19 μg ml−1], exo-polysaccharides (21 μg ml−1, HCN and ammonia. Under pesticide-stress, pesticide-concentration dependent progressive-decline in all plant growth promoting traits of the Mesorhizobium sp. strain MRC4 exposed was observed except for exo-polysaccharides which consistently increased with exceeding the concentration of each pesticide from recommended dose. For instance, hexaconazole at three times the recommended dose elicited the maximum stress on siderophore-biosynthesis by the Mesorhizobium sp. strain MRC4 and decreased salicylic acid and DHBA by 40% and 47%, respectively and the greatest stimulatory effect on exo-polysaccharides secretion was shown by imidacloprid which stimulated the Mesorhizobium sp. strain MRC4 to secrete EPS by 38%, compared to control. Generally, the maximum toxicity to plant growth promoting traits of Mesorhizobium was shown by glyphosate, thiamethoxam and hexaconazole, at three times the recommended rate among herbicides, insecticides and fungicides, respectively. This study revealed an additional aspect of the toxicological

  4. Effects of Strain Rate and Temperature on the Mechanical Properties of Medium Manganese Steels

    Energy Technology Data Exchange (ETDEWEB)

    Rana, Radhakanta [Colorado School of Mines, Golden, CO (United States); Matlock, David K [Colorado School of Mines, Golden, CO (United States); Speer, John G [Colorado School of Mines, Golden, CO (United States); De Moor, Emmanuel [Colorado School of Mines, Golden, CO (United States)

    2016-11-16

    The effects of temperature (-60 to 100 °C) and strain rate (0.002 to 0.2 s-1) on the properties of Al-alloyed 7 and 10 wt-% Mn steels containing 34.8 and 57.3 vol-% austenite respectively were evaluated by tensile tests in isothermal liquid baths. The tensile strengths of both medium Mn steels increased with a decrease in temperature owing to the decreased austenite stability with a decrease in temperature. At lower temperatures the strength of the 10MnAl steel was highest, a consequence of the higher strain hardening rate caused by more austenite transformation to martensite with deformation. The resulting properties are assessed with a consideration of the effects of strain rate and deformation on adiabatic heating which was observed to be as high as 95o C.

  5. Three-dimensional microstructural effects on plane strain ductile crack growth

    DEFF Research Database (Denmark)

    Tvergaard, Viggo; Needleman, Alan

    2006-01-01

    Ductile crack growth under mode 1, plane strain, small scale yielding conditions is analyzed. Overall plane strain loading is prescribed, but a full 3D analysis is carried out to model three dimensional microstructural effects. An elastic-viscoplastic constitutive relation for a porous plastic...... solid is used to model the material. Two populations of secondphase particles are represented, large inclusions with low strength, which result in large voids near the crack tip at an early stage, and small second-phase particles, which require large strains before cavities nucleate. The larger...... inclusions are represented discretely and the effects of different three dimensional distributions on the crack path and on the overall crack growth rate are analyzed. For comparison purposes, a two dimensional distribution of cylindrical inclusions is analyzed. Crack growth occurs off the initial crack...

  6. Stress-strain effects on powder-in-tube MgB2 tapes and wires

    International Nuclear Information System (INIS)

    Katagiri, Kazumune; Takaya, Ryuya; Kasaba, Koichi; Tachikawa, Kyoji; Yamada, Yutaka; Shimura, Satoshi; Koshizuka, Naoki; Watanabe, Kazuo

    2005-01-01

    The effects of stress-strain on the critical current, I c , of ex situ powder-in-tube (PIT)-processed Ni-sheathed MgB 2 tapes and round wires as well as in situ PIT-processed Cu-sheathed wires at 4.2 K in a magnetic field up to 5 T have been studied. The effect of In powder addition on the Ni-sheathed MgB 2 wire was not so clear compared with that in the tape, in which the irreversible strain, ε irr , for the I c degradation onset increases significantly by the addition. This is attributed to the difference in the microstructure of the core associated with cold workings. A peak and gradual degradation behaviour of I c with strain beyond ε irr was found in the wire, whereas no evident peak and a steep degradation behaviour was found in the tape. As a possible reason, the difference in the triaxial residual stress state at 4.2 K due to the difference in geometry of the cross-section is suspected. The transverse compression tests revealed that I c of the wire did not degrade up to 270 MPa. Again, the effect of In addition was minimal. The Young's modulus of MgB 2 , 31-41 GPa, at room temperature was estimated by a tensile test of Cu sheath wire using a high-accuracy extensometer and the law of mixtures. The tensile strain dependence of I c in the Cu sheath wire was similar to that in the Ni-sheathed wire, ε irr being 0.4%. However, the stress corresponding to ε irr , 50 MPa, was about 1/10 of that for the Ni-sheath wire and the irreversible transverse compressive stress, 150 MPa, was also lower. The effect of bending strain on the I c in Cu-sheathed wire was compared with that of the tensile strain

  7. The effects of low tidal ventilation on lung strain correlate with respiratory system compliance.

    Science.gov (United States)

    Xie, Jianfeng; Jin, Fang; Pan, Chun; Liu, Songqiao; Liu, Ling; Xu, Jingyuan; Yang, Yi; Qiu, Haibo

    2017-02-03

    The effect of alterations in tidal volume on mortality of acute respiratory distress syndrome (ARDS) is determined by respiratory system compliance. We aimed to investigate the effects of different tidal volumes on lung strain in ARDS patients who had various levels of respiratory system compliance. Nineteen patients were divided into high (C high group) and low (C low group) respiratory system compliance groups based on their respiratory system compliance values. We defined compliance ≥0.6 ml/(cmH 2 O/kg) as C high and compliance respiratory system compliance. The mean baseline EELV, strain and respiratory system compliance values were 1873 ml, 0.31 and 0.65 ml/(cmH 2 O/kg), respectively; differences in all of these parameters were statistically significant between the two groups. For all participants, a positive correlation was found between the respiratory system compliance and EELV (R = 0.488, p = 0.034). Driving pressure and strain increased together as the tidal volume increased from 6 ml/kg predicted body weight (PBW) to 12 ml/kg PBW. Compared to the C high ARDS patients, the driving pressure was significantly higher in the C low patients at each tidal volume. Similar effects of lung strain were found for tidal volumes of 6 and 8 ml/kg PBW. The "lung injury" limits for driving pressure and lung strain were much easier to exceed with increases in the tidal volume in C low patients. Respiratory system compliance affected the relationships between tidal volume and driving pressure and lung strain in ARDS patients. These results showed that increasing tidal volume induced lung injury more easily in patients with low respiratory system compliance. Clinicaltrials.gov identifier NCT01864668 , Registered 21 May 2013.

  8. Modeling the kinematic effect of horizontal strain rates on firn depth-density profiles

    Science.gov (United States)

    Horlings, A. N.; Stevens, C. M.; Holschuh, N.; Christianson, K. A.; Waddington, E. D.

    2017-12-01

    Firn compaction must be considered in interpretation of satellite repeat-altimetry measurements for ice-sheet mass balance estimates that are used to determine land-ice contribution to sea-level change. Firn compaction models remain the largest source of uncertainty in determining ice-sheet mass balance from repeat altimetry because the physical processes responsible for firn compaction are not fully understood. Most commonly used firn compaction models are 1-D, empirical or semi-empirical, and built on steady-state assumptions. These assumptions may be inappropriate in some regions, particularly areas of dynamic flow. In many of these regions, the horizontal strain rate due to dynamic ice flow can be similar in magnitude to the vertical strain rate from firn compaction. Therefore, horizontal stresses are important to consider in calculating firn depth-density profiles, yet are not represented in the current generation of firn compaction models. Here, we incorporate the kinematic effect of longitudinal strain on firn depth-density profiles in the dry snow zone. In every time step, the firn first densifies and consequently thins via a firn densification model; then, the firn stretches (thins) as stipulated by an imposed longitudinal strain rate without further density changes. Idealized tests show that the kinematic effect for longitudinal strain rates larger than 10-4 yr-1 can significantly decrease the depth-integrated porosity (> 0.5m) for climatic conditions representative of northeast Greenland. For conditions common on Thwaites Glacier, West Antarctica, results indicate that the kinematic effect on the firn column can shallow the bubble close-off depth by 20m and decrease the depth-integrated porosity by 7m. These results suggest that incorporating horizontal stresses into firn compaction models is essential to accurately model firn depth-density profiles in regions of ice sheets with high horizontal strain rates.

  9. Different effects of BCG strains - A natural experiment evaluating the impact of the Danish and the Russian BCG strains on morbidity and scar formation in Guinea-Bissau

    DEFF Research Database (Denmark)

    Frankel, H; Byberg, S; Andersen, Morten Bjerregaard

    2016-01-01

    BACKGROUND: Different Bacillus Calmette-Guerin (BCG) vaccine strains may have different non-specific effects. We assessed the effect of two BCG strains (Danish and Russian) on childhood morbidity and BCG scarification in Guinea-Bissau. METHODS: During 2011-2013, infants in the Bandim Health Project......'s urban study area received the Danish or Russian BCG in a natural experiment. Health center consultations were registered at point of care and scar status and size at age 4½ months. We assessed the effect of strain on consultation rates between vaccination and age 45days in Cox proportional hazards...... models. Scar prevalence and size were compared using binomial regression and ranksum tests. RESULTS: Among 1206 children, 18% received Danish BCG (n=215) and 82% Russian BCG (n=991). The adjusted hazard ratio (aHR) for consultations was 0.94 (95% CI 0.60-1.46) for Danish BCG compared with Russian BCG...

  10. Effect of Multi-Axial Loading on Residual Strain Tensor for 12L14 Steel Alloy

    Science.gov (United States)

    Bunn, Jeffrey R.; Penumadu, Dayakar; Lou, Xin; Hubbard, Camden R.

    2014-08-01

    Evaluating the state of residual strain or stress is critically important for structural materials and for reliable design of complex shape components that need to function in extreme environment subjected to large thermo-mechanical loading. When residual stress state is superposed to external loads, it can lead to reduction or increase in failure strength. Past diffraction studies for evaluating the residual strain state involved measuring lattice spacings in three orthogonal directions and do not often correspond to principal directions. To completely resolve the state of strain at a given location, a full strain tensor must be determined. This is especially important when characterizing materials or metallic components exposed to biaxial or complex loading. Neutron diffraction at the second Generation Neutron Residual Stress Facility (NRSF2) at Oak Ridge National Laboratory is used in this study to measure strain tensors associated with different modes of stress path. Hollow cylinder steel samples with 2 mm wall thickness are subjected to either pure axial extension or pure torsion to simulate multi-axial loading conditions. A virgin sample that is not subjected to any deformation, but subjected to identical manufacturing conditions and machining steps involved to obtain hollow cylinder geometry is used for obtaining reference d-spacing for given hkl planes at target spatial location(s). The two samples which are subjected to either pure tension or torsion are loaded to a deformation state that corresponded to equal amount of octahedral shear strain which is an invariant. This procedure is used so that a basis for comparison between the two samples can be made to isolate the stress path effects. A 2-circle Huber orienteer is used to obtain strain measurements on identical gauge volume at a series of φ and ψ values. The residual state of stress tensor corresponding to ex situ (upon unloading) conditions is presented for three lattice planes (211, 110, 200) for

  11. Axial‐type olivine crystallographic preferred orientations: the effect of strain geometry on mantle texture

    NARCIS (Netherlands)

    Chatzaras, V.; Kruckenberg, Seth C.; Cohen, Shaina M.; Medaris Jr., L. Gordon; Withers, Anthony C.; Bagley, Brian

    The effect of finite strain geometry on crystallographic preferred orientation (CPO) is poorly constrained in the upper mantle. Specifically, the relationship between shape preferred orientation (SPO) and CPO in the mantle rocks remains unclear. We analyzed a suite of 40 spinel peridotite xenoliths

  12. Effect of training on physical capacity and physical strain in persons with tetraplegia

    NARCIS (Netherlands)

    Dallmeijer, A J; Hopman, M T; Angenot, E L; van der Woude, L H

    The effects of quad rugby training on physical capacity and physical strain during standardized activities of daily living were investigated in 9 trained (A) and 5 untrained quad rugby players (B), and 7 inactive persons with tetraplegia (C) at 0, 3 and 6 months after the start of a quad rugby

  13. Effect of cumulative strain on texture characteristics during wire drawing of eutectoid steels

    International Nuclear Information System (INIS)

    Yang, F.; Ma, C.; Jiang, J.Q.; Feng, H.P.; Zhai, S.Y.

    2008-01-01

    The texture characteristics associated with plastic deformation of Fe-C steels near-eutectoid composition during a continuous cold drawing process were thoroughly investigated by orientation distribution function analysis based on X-ray diffraction. The effect of cumulative drawing strains on the fiber texture in drawn hypereutectoid and hypoeutectoid steel wires was discussed

  14. Effect of compressive strain on electric resistance of multi-wall carbon nanotube networks

    Czech Academy of Sciences Publication Activity Database

    Slobodian, P.; Říha, Pavel; Lengálová, A.; Olejník, R.; Kimmer, D.; Sáha, P.

    2011-01-01

    Roč. 6, č. 3 (2011), s. 294-304 ISSN 1745-8080 R&D Projects: GA AV ČR IAA200600803 Institutional research plan: CEZ:AV0Z20600510 Keywords : MWNT network * electric resistance * buckypaper * strain effect Subject RIV: JB - Sensors, Measurment, Regulation Impact factor: 1.011, year: 2011

  15. Pb nanoprecipitates in Al: Magic-shape effects due to elastic strain

    DEFF Research Database (Denmark)

    Hamilton, J.C.; Leoard, F.; Johnson, Erik

    2007-01-01

    We present a theory for size-dependent shapes of Pb nanoprecipitates in Al, introducing the concept of "magic shapes," i.e., shapes having near-zero homogeneous elastic strains. Our quantitative atomistic calculations of edge energies show their effect on precipitate shape to be negligible, thus...

  16. Mechanical advantage in wheelchair lever propulsion : effect on physical strain and efficiency

    NARCIS (Netherlands)

    van der Woude, L H; Botden, E; Vriend, I; Veeger, DirkJan (H. E. J.)

    In this experimental study on a prototype lever-propelled wheelchair, the effect of a range of mechanical advantages (MA) on physical strain, oxygen uptake, energy cost, mechanical efficiency, stroke frequency and perceived exertion was examined. Nine out of 10 male nonwheelchair users successfully

  17. Effect of salt stress on the physiology of Frankia sp strain CcI6

    Indian Academy of Sciences (India)

    2013-10-01

    Oct 1, 2013 ... production and nitrogenase activity were also influenced by NaCl. [Oshone R, Mansour SR and Tisa LS 2013 Effect of salt stress on the physiology of Frankia sp strain CcI6. J. Biosci. 38 699–702] DOI 10.1007/s12038-. 013-9371-2. 1. Introduction. Among the soil-dwelling actinobacteria, members of the.

  18. Effect of dietary protein on performance of four broiler strains and on ...

    African Journals Online (AJOL)

    student

    2013-03-09

    Mar 9, 2013 ... Data for breast meat and body protein weight from each bird sampled were used to calculate allometric equations for each strain, sex and feed protein level, which were compared using simple linear regression with groups in Genstat (2002), the respective coefficients for the main effects of the three factors ...

  19. Identification of an Actual Strain-Induced Effect on Fast Ion Conduction in a Thin-Film Electrolyte.

    Science.gov (United States)

    Ahn, Junsung; Jang, Ho Won; Ji, Hoil; Kim, Hyoungchul; Yoon, Kyung Joong; Son, Ji-Won; Kim, Byung-Kook; Lee, Hae-Weon; Lee, Jong-Ho

    2018-04-11

    Strain-induced fast ion conduction has been a research area of interest for nanoscale energy conversion and storage systems. However, because of significant discrepancies in the interpretation of strain effects, there remains a lack of understanding of how fast ionic transport can be achieved by strain effects and how strain can be controlled in a nanoscale system. In this study, we investigated strain effects on the ionic conductivity of Gd 0.2 Ce 0.8 O 1.9-δ (100) thin films under well controlled experimental conditions, in which errors due to the external environment could not intervene during the conductivity measurement. In order to avoid any interference from perpendicular-to-surface defects, such as grain boundaries, the ionic conductivity was measured in the out-of-plane direction by electrochemical impedance spectroscopy analysis. With varying film thickness, we found that a thicker film has a lower activation energy of ionic conduction. In addition, careful strain analysis using both reciprocal space mapping and strain mapping in transmission electron microscopy shows that a thicker film has a higher tensile strain than a thinner film. Furthermore, the tensile strain of thicker film was mostly developed near a grain boundary, which indicates that intrinsic strain is dominant rather than epitaxial or thermal strain during thin-film deposition and growth via the Volmer-Weber (island) growth mode.

  20. Effects of Low Temperature and High Strain Rate on the Tensile Behaviors of High-Performance Energetic Composite

    Directory of Open Access Journals (Sweden)

    Wang Zhe Jun

    2016-01-01

    Full Text Available To further study the effects of low temperature and high strain rate on the tensile behaviors of hydroxyl-terminated polybutadiene (HTPB propellant, an INSTRON testing machine was applied for carrying out the uniaxial tensile tests at low temperatures and room temperature after storage at low temperatures. The strain rates are in the range of 0.40 to 85.71 s−1. Scanning electron microscope (SEM was used for examining the failure mechanisms of HTPB propellant under the test conditions. The results reveal that HTPB propellant is still capable of large deformation at lower strain rates and low temperatures in the glass transition and glass state. The characteristics of stress-strain curves at room temperature after storage at low temperatures are the same with that directly obtained at room temperature. The effect of strain rate on the elastic modulus E at various temperatures is almost the same. However, the effect of strain rate on the maximum tensile stress σm becomes weak with decreasing temperature. Furthermore, the strain εm is nearly independence of the strain rate at higher strain rates and the lowest test temperature in glass state. Continuously decreasing temperature can more easily cause the extensive brittle fracture of AP particles, even at lower strain rates. The temperature changes from room temperature to low temperature and then from low temperature to room temperature in a short time cannot influence the failure mechanism of HTPB propellant at room temperature and high strain rate.

  1. Strain gradient effects on steady state crack growth in rate-sensitive materials

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau; Niordson, Christian Frithiof; Hutchinson, John W.

    2012-01-01

    , a characteristic velocity, at which the toughness becomes independent of the rate-sensitivity, has been observed. It is the aim to bring forward a similar characteristic velocity for the current strain gradient visco-plastic model, as-well as to signify its use in future visco-plastic material modeling....... of a homogeneous rate-sensitive metal, using a higher order plasticity theory. Throughout, emphasis is on the toughness rate-sensitivity, as a recent numerical study of a conventional material (no gradient effects) has indicated a significant influence of both strain rate hardening and crack tip velocity. Moreover...

  2. Effect of steam oxidation on strength, elastic modulus, and strain at fracture of graphite 2020

    International Nuclear Information System (INIS)

    Velasquez, C.; Hightower, G.; Burnette, R.

    1977-12-01

    Stackpole Carbon's graphite grade 2020, a candidate material for support posts in GA HTGRs, was oxidized in steam-helium mixtures to 25 wt % burnoff. The effects of the oxidation on ultimate strength, elastic modulus, and strain at fracture are reported. A large number of nonoxidized and oxidized tensile specimens were tested to failure. Average losses of 6.7 wt % in strength and 7.4 wt % in elastic modulus at 1% burnoff were obtained. No significant change in strain at fracture was observed for burnoffs up to 5%. The elastic modulus and ultimate tensile strength of the oxidized samples correlated with bulk density

  3. Numerical Evaluation of Size Effect on the Stress-Strain Behaviour of Geotextile-Reinforced Sand

    DEFF Research Database (Denmark)

    Hosseinpour, I.; Mirmoradi, S.H.; Barari, Amin

    2010-01-01

    , the confining pressure and the type of geotextile. Modeling was performed on samples with five different diameters: 38, 100, 200, 500 and 600 mm. The elastic-plastic Mohr-Coulomb model was used to simulate sand behavior. Results showed that small-sized samples show higher values of peak strength and higher......This paper studies the effect of sample size on the stress-strain behavior and strength characteristics of geotextile reinforced sand using the finite element numerical analysis. The effect of sample size was investigated by studying the effects of varying the number of geotextile layers...... axial strain at failure in comparison with large-sized samples. The size effect on the behavior of samples became further apparent when the number of geotextile layers was increased or the confining pressure was decreased. In addition, the results indicated that the magnitude of the size effect...

  4. ADP-ribosyltransferases: plastic tools for inactivating protein and small molecular weight targets

    OpenAIRE

    Koch-Nolte, Friedrich; Reche, Pedro A; Haag, Friedrich; Bazan, Fernando

    2001-01-01

    ADP-ribosyltransferases (ADPRTs) form an interesting class of enzymes with well-established roles as potent bacterial toxins and metabolic regulators. ADPRTs catalyze the transfer of the ADP-ribose moiety from NAD(+) onto specific substrates including proteins. ADP-ribosylation usually inactivates the function of the target. ADPRTs have become adapted to function in extra- and intracellular settings. Regulation of ADPRT activity can be mediated by ligand binding to associated regulatory domai...

  5. Effect of Luting Cement Space on the Strain Response of Gold Crowns Under Static Compressive Loading.

    Science.gov (United States)

    Asbia, S; Ibbetson, R; Reuben, B

    2015-03-01

    The aim the work was to investigate the effect of varying degrees of luting cement thickness on the strain of the cemented gold alloy crowns under compression. Five dies with their corresponding crowns were fabricated using a lost wax technique. Three gold crowns for each die were fabricated under the control of specific die spacer layers to provide a space of 40 µm (10 layers of die-spacer thickness) and 80 µm (20 layers of die-spacer thickness). The crowns were subsequently cemented using zinc phosphate cement. The crowns were subjected to gradual static compressive loading between 10N to 250N (Newton) and the strain measured simultaneously. The results were statistically analysed using Independent t-test for the different die-spacer thickness at the 95% confidence interval (p = 0.05). It was found that a significant relationship in the three thicknesses. It was concluded that the absence of die-spacer significantly reduced strain response, whereas a very little change in the strain recorded as the die spacer layers has increased. Clinically, decreasing the number of die-spacer layers is advantageous as it provides a lower strain response under static compressive loading that would improve the longevity of the cemented full crowns inside the patient's mouth.

  6. Effect of Strain Rate on Joint Strength and Failure Mode of Lead-Free Solder Joints

    Science.gov (United States)

    Lin, Jian; Lei, Yongping; Fu, Hanguang; Guo, Fu

    2018-03-01

    In surface mount technology, the Sn-3.0Ag-0.5Cu solder joint has a shorter impact lifetime than a traditional lead-tin solder joint. In order to improve the impact property of SnAgCu lead-free solder joints and identify the effect of silver content on tensile strength and impact property, impact experiments were conducted at various strain rates on three selected SnAgCu based solder joints. It was found that joint failure mainly occurred in the solder material with large plastic deformation under low strain rate, while joint failure occurred at the brittle intermetallic compound layer without any plastic deformation at a high strain rate. Joint strength increased with the silver content in SnAgCu alloys in static tensile tests, while the impact property of the solder joint decreased with increasing silver content. When the strain rate was low, plastic deformation occurred with failure and the tensile strength of the Sn-3.0Ag-0.5Cu solder joint was higher than that of Sn-0.3Ag-0.7Cu; when the strain rate was high, joint failure mainly occurred at the brittle interface layer and the Sn-0.3Ag-0.7Cu solder joint had a better impact resistance with a thinner intermetallic compound layer.

  7. Enhanced Switchable Ferroelectric Photovoltaic Effects in Hexagonal Ferrite Thin Films via Strain Engineering.

    Science.gov (United States)

    Han, Hyeon; Kim, Donghoon; Chu, Kanghyun; Park, Jucheol; Nam, Sang Yeol; Heo, Seungyang; Yang, Chan-Ho; Jang, Hyun Myung

    2018-01-17

    Ferroelectric photovoltaics (FPVs) are being extensively investigated by virtue of switchable photovoltaic responses and anomalously high photovoltages of ∼10 4 V. However, FPVs suffer from extremely low photocurrents due to their wide band gaps (E g ). Here, we present a promising FPV based on hexagonal YbFeO 3 (h-YbFO) thin-film heterostructure by exploiting its narrow E g . More importantly, we demonstrate enhanced FPV effects by suitably exploiting the substrate-induced film strain in these h-YbFO-based photovoltaics. A compressive-strained h-YbFO/Pt/MgO heterojunction device shows ∼3 times enhanced photovoltaic efficiency than that of a tensile-strained h-YbFO/Pt/Al 2 O 3 device. We have shown that the enhanced photovoltaic efficiency mainly stems from the enhanced photon absorption over a wide range of the photon energy, coupled with the enhanced polarization under a compressive strain. Density functional theory studies indicate that the compressive strain reduces E g substantially and enhances the strength of d-d transitions. This study will set a new standard for determining substrates toward thin-film photovoltaics and optoelectronic devices.

  8. 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.

  9. Textile-Based Weft Knitted Strain Sensors: Effect of Fabric Parameters on Sensor Properties

    Directory of Open Access Journals (Sweden)

    William Richard Kennon

    2013-08-01

    Full Text Available The design and development of textile-based strain sensors has been a focus of research and many investigators have studied this subject. This paper presents a new textile-based strain sensor design and shows the effect of base fabric parameters on its sensing properties. Sensing fabric could be used to measure articulations of the human body in the real environment. The strain sensing fabric was produced by using electronic flat-bed knitting technology; the base fabric was produced with elastomeric yarns in an interlock arrangement and a conductive yarn was embedded in this substrate to create a series of single loop structures. Experimental results show that there is a strong relationship between base fabric parameters and sensor properties.

  10. Antimicrobial effect against different bacterial strains and bacterial adaptation to essential oils used as feed additives.

    Science.gov (United States)

    Melo, Antonio Diego Brandão; Amaral, Amanda Figueiredo; Schaefer, Gustavo; Luciano, Fernando Bittencourt; de Andrade, Carla; Costa, Leandro Batista; Rostagno, Marcos Horácio

    2015-10-01

    The aim of this study was to evaluate the antimicrobial activity and determine the minimum bactericidal concentration (MBC) of the essential oils derived from Origanum vulgare (oregano), Melaleuca alternifolia (tea tree), Cinnamomum cassia (cassia), and Thymus vulgaris (white thyme) against Salmonella Typhimurium, Salmonella Enteritidis, Escherichia coli, Staphylococcus aureus and Enterococcus faecalis. The study also investigated the ability of these different bacterial strains to develop adaptation after repetitive exposure to sub-lethal concentrations of these essential oils. The MBC of the essential oils studied was determined by disc diffusion and broth dilution methods. All essential oils showed antimicrobial effect against all bacterial strains. In general, the development of adaptation varied according to the bacterial strain and the essential oil (tea tree > white thyme > oregano). Therefore, it is important to use essential oils at efficient bactericidal doses in animal feed, food, and sanitizers, since bacteria can rapidly develop adaptation when exposed to sub-lethal concentrations of these oils.

  11. A Study on the Effect of Strain Rate on the Dynamic Recrystallization Mechanism of Alloy 617B

    Science.gov (United States)

    Jiang, He; Dong, Jianxin; Zhang, Maicang; Yao, Zhihao

    2016-10-01

    The effect of strain rate on dynamic recrystallization (DRX) behavior and mechanism of alloy 617B was investigated by isothermal compression test in a temperature range of 1393 K to 1483 K (1120 °C to 1210 °C) with a wide strain rate scope of 0.01 to 20 s-1. The microstructure evolution was investigated comprehensively by optical microscopy, electron backscatter diffraction (EBSD), electron channeling contrast imaging (ECCI), and transmission electron microscopy (TEM) to provide detailed insight into the effect of strain rate on DRX mechanism. The study shows that DRX is accelerated at both low strain rate and high strain rate conditions with an apparent sluggish kinetics at the intermediate strain rate of 1 s-1. In the low strain rate condition ( i.e., strain rate is higher than 1 s-1, besides the commonly accepted reason of adiabatic heat generated by high strain rate, enhanced DRX nucleation mechanism is crucial for the promotion of DRX at high strain rate. High strain rate could lead to enhanced pile-up of dislocation and higher stored energy, which can facilitate the process of DRX. In addition, distortion or subdivision of twins and "grain fragment" are detected when the strain rate is higher than 1 s-1, which provide additional DRX nucleation mechanism. As a result, the combined effect leads to the higher DRX nucleation rate to promote DRX at high strain rate. The effect of strain rate on DRX is the completion result between sufficiency of time on the one hand and adiabatic heat and enhanced nucleation mechanism on the other.

  12. Regulation of nucleocytoplasmic transport by ADP-ribosylation: the emerging role of karyopherin-β1 mono-ADP-ribosylation by ARTD15.

    Science.gov (United States)

    Di Girolamo, Maria

    2015-01-01

    Post-translational modifications of a cellular protein by mono- and poly-ADP-ribosylation involve the cleavage of NAD (+) , with the release of its nicotinamide moiety. This is accompanied by the transfer of a single (mono-) or several (poly-) ADP-ribose molecules from NAD (+) to a specific amino-acid residue of the protein. Recent reports have shed new light on the correlation between NAD (+) -dependent ADP-ribosylation reactions and the endoplasmic reticulum, in addition to the well-documented roles of these reactions in the nucleus and mitochondria. We have demonstrated that ARTD15/PARP16 is a novel mono-ADP-ribosyltransferase with a new intracellular location, as it is associated with the endoplasmic reticulum. The endoplasmic reticulum, which is a membranous network of interconnected tubules and cisternae, is responsible for specialised cellular functions, including protein folding and protein transport. Maintenance of specialised cellular functions requires the correct flow of information between separate organelles that is made possible through the nucleocytoplasmic trafficking of proteins. ARTD15 appears to have a role in nucleocytoplasmic shuttling, through karyopherin-β1 mono-ADP-ribosylation. This is in line with the emerging role of ADP-ribosylation in the regulation of intracellular trafficking of cellular proteins. Indeed, other, ADP-ribosyltransferases like ARTD1/PARP1, have been reported to regulate nucleocytoplasmic trafficking of crucial proteins, including p53 and NF-κB, and as a consequence, to modulate the subcellular localisation of these proteins under both physiological and pathological conditions.

  13. Effect of Bacteriophages on the Growth of Flavobacterium psychrophilum and Development of Phage-Resistant Strains

    DEFF Research Database (Denmark)

    Christiansen, Rói Hammershaimb; Madsen, Lone; Dalsgaard, Inger

    2016-01-01

    The controlling effect of single and multiple phages on the density of Flavobacterium psychrophilum at different initial multiplicity of infection (MOI) was assessed in batch cultures to explore the potential for phage-based treatment of this important fish pathogen. A high initial phage concentr...... is essential for fast and effective control of F. psychrophilum infection and suggest that the small populations of resistant clones had reduced competitive abilities relative to the sensitive ancestral strain.......The controlling effect of single and multiple phages on the density of Flavobacterium psychrophilum at different initial multiplicity of infection (MOI) was assessed in batch cultures to explore the potential for phage-based treatment of this important fish pathogen. A high initial phage...... and resistant strains were isolated for further characterization. The application of a mathematical model allowed simulation of phage-host interactions and resistance development, confirming indications from strain isolations that phage-sensitive strains dominated the regrowing population (>99.8 %) at low MOI...

  14. Strain-specific differences of the effects of stress on memory in Lymnaea.

    Science.gov (United States)

    Hughes, Emily; Shymansky, Tamila; Swinton, Erin; Lukowiak, Kai S; Swinton, Cayley; Sunada, Hiroshi; Protheroe, Amy; Phillips, Iain; Lukowiak, Ken

    2017-03-01

    Stress alters the ability to form, recall and maintain memory according to the Yerkes-Dodson/Hebb (YDH) law. The effects of environmentally relevant stressors, such as low environmental calcium and crowding, on learning and memory have previously been described in a laboratory-reared 'average' strain of Lymnaea stagnalis (i.e. the Dutch strain) as well as two strains of freshly collected L . stagnalis with enhanced memory formation abilities (i.e. 'smart' snails). Here, we use L . stagnalis to study the effects of other environmentally relevant stressors on memory formation in two other strains of freshly collected snails, one 'smart' and one 'average'. The stressors we examined are thermal, resource restriction combined with food odour, predator detection and, for the first time, tissue injury (shell damage). We show that the same stressor has significantly different effects on memory formation depending on whether snails are 'smart' or 'average'. Specifically, our data suggest that a stressor or a combination of stressors act to enhance memory in 'average' snails but obstruct memory formation in 'smart' snails. These results are consistent with the YDH law and our hypothesis that 'smart' snails are more easily stressed than 'average' snails. © 2017. Published by The Company of Biologists Ltd.

  15. A minimum structured adenine nucleotide for ADP/ATP transport in mitochondria.

    Science.gov (United States)

    Schlimme, E; Boos, K S; Renz, H

    1988-10-01

    An ADP analogue, i.e. 3H- or 14C-labeled 5'-diphosphate of 6-(beta-D-ribofuranosyl-methyl)-4-pyrimidinamine, was synthesized, the structure of which was deduced from structure-activity studies on the substrate specificity of the nucleotide-binding center of the inner mitochondrial membrane integrated ADP/ATP carrier protein. Bearing only the minimal but substrate-essential recognition structures, minimum structured ADP (msADP) is bound to the cytosol-facing active center and transported by the highly specific carrier system across the inner mitochondrial membrane.

  16. Rat platelet aggregation by ATP. Aggregometrical and ultrastructural comparison with aggregations induced by ADP and collagen.

    Science.gov (United States)

    Ts'ao, C.

    1976-01-01

    This paper describes the aggregation of rat platelets by adenosine triphosphate (ATP). The aggregometry of ATP-induced aggregation and the ultrastructure of ATP-aggregated platelets were compared and contrasted with those of adenosine diphosphate (ADP)-treated and collagen-treated samples. Human platelets were also studied alongside with rat specimens. Several lines of evidence indicate that the ATP-induced aggregation of rat platelet-rich plasma (PRP) is not a result of contaminating ADP in the ATP preparation. ATP did not cause aggregation of human platelets; it inhibited ADP- and collagen-induced human platelet aggregation. ATP pretreated with a creatine phosphate/creatine phosphokinase system caused similar rat platelet aggregation as did ATP not treated with this system. The aggregometry of ATP-induced aggregation of rat PRP was similar to that of collagen-induced aggregation but markedly different from that of ADP-induced aggregation. However, the nature of ATP-induced aggregation was similar to that induced by ADP. Both ATP- and ADP-induced rat platelet aggregations were not affected by adenosine, adenosine monophosphate, or acetylsalicylic acid. The ultrastructure of ATP-aggregated platelets was similar to that of ADP-aggregated ones. It appears that either platelets of rats possess specific ATP receptors or the rat plasma contains a material, lacking or insufficiently present in human plasma, that converts ATP to ADP in a fashion similar to the release of ADP from platelet storage granules. Images Figure 1 PMID:998732

  17. Cholera toxin can catalyze ADP-ribosylation of cytoskeletal proteins

    International Nuclear Information System (INIS)

    Kaslow, H.R.; Groppi, V.E.; Abood, M.E.; Bourne, H.R.

    1981-01-01

    Cholera toxin catalyzes transfer of radiolabel from [ 32 P]NAD + to several peptides in particulate preparations of human foreskin fibroblasts. Resolution of these peptides by two-dimensional gel electrophoresis allowed identification of two peptides of M/sub r/ = 42,000 and 52,000 as peptide subunits of a regulatory component of adenylate cyclase. The radiolabeling of another group of peptides (M/sub r/ = 50,000 to 65,000) suggested that cholera toxin could catalyze ADP-ribosylation of cytoskeletal proteins. This suggestion was confirmed by showing that incubation with cholera toxin and [ 32 P]NAD + caused radiolabeling of purified microtubule and intermediate filament proteins

  18. Poly(ADP-ribose): From chemical synthesis to drug design.

    Science.gov (United States)

    Drenichev, Mikhail S; Mikhailov, Sergey N

    2016-08-01

    Poly(ADP-ribose) (PAR) is an important biopolymer, which is involved in various life processes such as DNA repair and replication, modulation of chromatin structure, transcription, cell differentiation, and in pathogenesis of various diseases such as cancer, diabetes, ischemia and inflammations. PAR is the most electronegative biopolymer and this property is essential for its binding with a wide range of proteins. Understanding of PAR functions in cell on molecular level requires chemical synthesis of regular PAR oligomers. Recently developed methodologies for chemical synthesis of PAR oligomers, will facilitate the study of various cellular processes, involving PAR. Copyright © 2016. Published by Elsevier Ltd.

  19. Enhancement of radiosensitivity of recombinant Ad-p53 gene on human lung adenocarcinoma cell with different p53 status

    International Nuclear Information System (INIS)

    Pang Dequan; Wang Peiguo; Wang Ping; Zhang Weiming

    2008-01-01

    Objective: To investigate the enhancement of radiosensitivity of recombinant Ad-p53 gene on human lung adenocarcinoma cell lines(A549 and GLC-82) with different p53 status in vitro. Methods: Two human lung adenocarcinoma cell lines of A549 and GLC-82 were examined on their difference in p53 status with immunohistochemistry stain and PCR-SSCP technique. Expand Ad-wtp53 was transfected into tumor cells. Clonogenic assays were performed to evaluate the inhibition effect on cell growth and the degree of sensitization to irradiation. Apoptosis and cell cycle changes were determined using the flow cytometry assay. Results: The A549 cell line presented positive P53 expression while GLC-82 negative. GLC-82 bore mutant p53 on the exon 7. The wtp53 gene could be efficiently expressed in the two cell lines and greatly inhibit the cell growth. Its efficiency didn't depend on the intrinsic p53 genetic status. After irradiation, its function of inducing G 1 arrest and apoptosis on GLC-82 cell line was much stronger than the A549 cell line. In both the A549 and GLC-82 cell lines, the combination of Ad-p53 plus radiation resulted in more apoptosis than the others. There was no significant difference between two groups. Conclusions: Ad-p53 can depress the tumor growth and enhance the radiosensitivity of human lung adenocarcinoma cells. And this effect is independent of endogenous p53 status. (authors)

  20. The effects of temperature and strain rate on the dynamic flow behaviour of different steels

    International Nuclear Information System (INIS)

    Lee, W.-S.; Liu, C.-Y.

    2006-01-01

    A compressive type split-Hopkinson pressure bar is utilized to compare the impact plastic behaviour of three steels with different levels of carbon content. S15C low carbon steel, S50C medium alloy heat treatable steel (abbreviated hereafter to medium carbon steel) and SKS93 tool steel with a high carbon and low alloy content (abbreviated hereafter to high carbon steel) are tested under strain rates ranging from 1.1 x 10 3 s -1 to 5.5 x 10 3 s -1 and temperatures ranging from 25 to 800 deg. C. The effects of the carbon content, strain rate and temperature on the mechanical responses of the three steels are evaluated. The microstructures of the impacted specimens are studied using a transmission electron microscope (TEM). It is found that an increased carbon content enhances the dynamic flow resistance of the three steels. Additionally, the flow stress increases with strain and strain rate in every case. A thermal softening effect is identified in the plastic behaviour of the three steels. The activation energy, ΔG * , varies as a function of the strain rate and temperature, but is apparently insensitive to the carbon content level. The present study identifies maximum ΔG * values of 58 kJ/mol for the S15C low carbon steel, 54.9 kJ/mol for the S50C medium carbon steel, and 56.4 kJ/mol for the SKS93 high carbon steel. A Zerilli-Armstrong BCC constitutive model with appropriate coefficients is applied to describe the high strain rate plastic behaviours of the S15C, S50C and SKS93 steels. The errors between the calculated stress and the measured stress are found to be less than 5%. The microstructural observations reveal that the dislocation density and the degree of dislocation tangling increase with increasing strain rate in all three steels. Additionally, the TEM observations indicate that a higher strain rate reduces the size of the dislocation cells. The annihilation of dislocations occurs more readily at elevated temperatures. The square root of the dislocation

  1. The effect of the strain path on the work hardening of austenitic and ferritic stainless steels in axisymmetric drawing

    Science.gov (United States)

    Cetlin, P. R.; Corrêa, E. C. S.; Aguilar, M. T. P.

    2003-03-01

    The work-hardening characteristics of metals deeply affect the analytical and numerical analyses of their forming processes and especially the end mechanical properties of the products manufactured. The effects of strain, strain rate, and temperature on work hardening have received wide attention in the literature, but the role of the strain path has been far less studied, except for sheet-metal forming. Strain-path effects seem to have never been analyzed for bulk-forming processes, such as axisymmetric drawing. In the present work, drawn bars were considered as composed of concentric layers strained along varying strain paths. The tensile von Mises effective stress, effective-strain curves of two layers and of the full cross section of the drawn material, were experimentally determined. The flow behavior of these regions was compared to that resulting from pure monotonic-tensile processing. The AISI 420 and 304 stainless steels revealed a strain path and a material effect on their work-hardening characteristics. Higher or lower hardening rates were observed in axisymmetric drawing, as compared to pure tension. These phenomena were interpreted by considering the dislocation arrangements caused by initial drawing straining and their subsequent restructuring, associated with the strain-path change represented by tension after drawing. The analytical and numerical analyses of the tensile behavior of metals following axisymmetric drawing must consider the strain-path effects on the constitutive equations laws and on the hardening behavior of the material. The redundant deformation factor in axisymmetric drawing ( φ) plays a central role in the analysis of the process and on the prediction of the mechanical properties of the final products. This parameter was evaluated considering (a) the strain distribution in the bar cross section caused by drawing or (b) the mechanical properties of the drawn bars. The comparison of the results from these two approaches allowed an

  2. 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

    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...... 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....

  3. Effects of strain rate, stress condition and environment on iodine embrittlement of Ziracloy-2

    International Nuclear Information System (INIS)

    Une, K.

    1979-01-01

    Iodine stress corrosion cracking (SCC) susceptibility of Zircaloy became higher with decreasing strain rate. Critical strain rate, below which high SCC severity was observed, substantially depended on Zircaloy stress condition. This strain rate (7 x 10 -3 min -1 ) under plane strain condition was about 3.5 times as fast as that (2 x 10 -3 min -1 ) under uniaxial condition. The maximum iodine embrittlement in Zircaloy was found in stress ratio α (axial/tangential stress) range of 0.5 to 0.7. No embrittlement occurred at α = infinity because of its texture effect. The SCC fracture stresses were about 39 kg/mm 2 for unirradiated and stress-relieved material, and about 34 kg/mm 2 for recrystallized material, whose ratios to yield strength of each material were 0.8 and 1.2. Impurity gases of oxygen and moisture in the iodine had the effects of reducing Zircaloy SCC susceptibility. Stress-relieved material was more sensitive to environmental impurities than recrystallized material

  4. The effects of orthotic intervention on multisegment foot kinematics and plantar fascia strain in recreational runners.

    Science.gov (United States)

    Sinclair, Jonathan; Isherwood, Josh; Taylor, Paul J

    2015-02-01

    Chronic injuries are a common complaint in recreational runners. Foot orthoses have been shown to be effective for the treatment of running injuries but their mechanical effects are still not well understood. This study aims to examine the influence of orthotic intervention on multisegment foot kinematics and plantar fascia strain during running. Fifteen male participants ran at 4.0 m · s(-1) with and without orthotics. Multisegment foot kinematics and plantar fascia strain were obtained during the stance phase and contrasted using paired t tests. Relative coronal plane range of motion of the midfoot relative to the rearfoot was significantly reduced with orthotics (1.0°) compared to without (2.2°). Similarly, relative transverse plane range of motion was significantly lower with orthotics (1.1°) compared to without (1.8°). Plantar fascia strain did not differ significantly between orthotic (7.1) and nonorthotic (7.1) conditions. This study shows that although orthotics did not serve to reduce plantar fascia strain, they are able to mediate reductions in coronal and transverse plane rotations of the midfoot.

  5. Protective effect of oral administration of transgenic tobacco seeds against verocytotoxic Escherichia coli strain in piglets.

    Science.gov (United States)

    Rossi, Luciana; Dell'Orto, Vittorio; Vagni, Simona; Sala, Vittorio; Reggi, Serena; Baldi, Antonella

    2014-03-01

    The use of transgenic plants as delivery system for antigenic proteins is attractive for its simplicity and increases likelihood for local immune response at sites of infection. The aim of this study was to evaluate the protective effect of oral administration of tobacco seeds, expressing the FedA, the major protein of the F18 adhesive fimbriae, and B subunit of verocytotoxin, against verocytotoxin-producing E. coli (VTEC) strain in piglets. Forty-three early weaned piglets, were randomly divided into 4 experimental groups: 3 test groups and a control. Treatment groups orally received a bolus, with different dose of tobacco seeds on 0, 1, 2, 14 days post primary administration. After challenge, with 1*10(10) CFU of O138 Escherichia coli strain, piglets showed clinical scores significantly higher in the control group compared to orally immunized groups (P administration of recombinant tobacco seeds expressing antigenic proteins against VTEC strains can induce a protective effect against challenger strain in piglets.

  6. The Effects of Smoking on Ultrasonographic Thickness and Elastosonographic Strain Ratio Measurements of Distal Femoral Cartilage

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    Harun R. Gungor

    2016-04-01

    Full Text Available Although adverse effects of smoking on bone health are all well known, data on how smoking interacts with cartilage structure in otherwise healthy individuals remains conflicting. Here, we ascertain the effects of cigarette smoking on sonoelastographic properties of distal femoral cartilage in asymptomatic adults. Demographic characteristics and smoking habits (packets/year of healthy volunteers were recorded. Medial, intercondylar, and lateral distal femoral cartilage thicknesses and strain ratios on the dominant extremity were measured with ultrasonography (US and real time US elastography. A total of 88 subjects (71 M, 17 F; aged 18–56 years, N = 43 smokers and N = 45 nonsmokers were evaluated. Mean amount of cigarette smoking was 10.3 ± 8.9 (1–45 packets/year. Medial, intercondylar and lateral cartilage were thicker in smokers than nonsmokers (p = 0.002, p = 0.017, and p = 0.004, respectively. Medial distal femoral cartilage strain ratio was lower in smokers (p = 0.003. The amount of smoking was positively correlated with cartilage thicknesses and negatively correlated with medial cartilage strain ratios (p < 0.05. Femoral cartilage is thicker in smokers but has less strain ratio representing harder cartilage on the medial side. Future studies are needed to understand how these structural changes in the knee cartilage should be interpreted with regard to the development of knee osteoarthritis in smokers.

  7. Local Effects on Strain Seismograms at Matsushiro Seismological Observatory - 2. Rayleigh Waves

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    Taishi Okamoto

    2007-01-01

    Full Text Available We evaluate local effects on strain seismograms for a Rayleigh wave observed at Matsushiro Seismological Observatory, Japan Meteorological Agency, central Japan, by applying a method proposed in a previous report (Okamoto et al. 2007. The method involves examination of polarization angles, local phase velocity, and accuracy of velocity seismograms. The results are as follows: 1 Polarization angles of observed strain seismograms agree with expected ones from those of velocity seismograms also observed at Matsushiro; 2 Local phase velocity estimated by comparison between strain and velocity seismograms is 54% larger than the theoretical value calculated from the PREM velocity model; 3 Velocity spectra observed at Matsushiro have almost the same amplitude as an average of those at F-net observation stations near Matsushiro. These results indicate that both EW and NS component strain seismograms observed at Matsushiro have been reduced by 35% in amplitude for a Rayleigh wave due to local heterogeneity. The local effects on a Rayleigh wave are quite different from that on a Love wave obtained in the previous report.

  8. Strain-Dependent Effect of Macroautophagy on Abnormally Folded Prion Protein Degradation in Infected Neuronal Cells.

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    Daisuke Ishibashi

    Full Text Available Prion diseases are neurodegenerative disorders caused by the accumulation of abnormal prion protein (PrPSc in the central nervous system. With the aim of elucidating the mechanism underlying the accumulation and degradation of PrPSc, we investigated the role of autophagy in its degradation, using cultured cells stably infected with distinct prion strains. The effects of pharmacological compounds that inhibit or stimulate the cellular signal transduction pathways that mediate autophagy during PrPSc degradation were evaluated. The accumulation of PrPSc in cells persistently infected with the prion strain Fukuoka-1 (FK, derived from a patient with Gerstmann-Sträussler-Scheinker syndrome, was significantly increased in cultures treated with the macroautophagy inhibitor 3-methyladenine (3MA but substantially reduced in those treated with the macroautophagy inducer rapamycin. The decrease in FK-derived PrPSc levels was mediated, at least in part, by the phosphatidylinositol 3-kinase/MEK signalling pathway. By contrast, neither rapamycin nor 3MA had any apparently effect on PrPSc from either the 22L or the Chandler strain, indicating that the degradation of PrPSc in host cells might be strain-dependent.

  9. Protective effects of indigenous Escherichia coli against a pathogenic E. coli challenge strain in pigs.

    Science.gov (United States)

    Vahjen, W; Cuisiniere, T; Zentek, J

    2017-10-13

    To investigate the inhibitory effect of indigenous enterobacteria on pathogenic Escherichia coli, a challenge trial with postweaning pigs was conducted. A pathogenic E. coli strain was administered to all animals and their health was closely monitored thereafter. Faecal samples were taken from three healthy and three diarrhoeic animals. Samples were cultivated on MacConkey agar and isolates were subcultured. A soft agar overlay assay was used to determine the inhibitory activity of the isolates. A total of 1,173 enterobacterial isolates were screened for their ability to inhibit the E. coli challenge strain. Colony forming units of enterobacteria on MacConkey agar were not different between healthy and diarrhoeic animals in the original samples. Furthermore, numbers of isolates per animal were also not significantly different between healthy (482 isolates) and diarrhoeic animals (691 isolates). A total of 43 isolates (3.7%) with inhibitory activity against the pathogenic E. coli challenge strain were detected. All inhibitory isolates were identified as E. coli via MALDI-TOF. The isolates belonged to the phylotypes A, C and E. Many isolates (67.4%) were commensal E. coli without relevant porcine pathogenic factors, but toxin- and fimbrial genes (stx2e, fae, estIb, elt1a, fas, fan) were detected in 14 inhibitory isolates. Healthy animals showed significantly (P=0.003) more inhibitory isolates (36 of 482 isolates; 7.5%) than diseased animals (7 of 691 isolates; 1.0%). There were no significant correlations regarding phylotype or pathogenic factors between healthy and diseased animals. This study has shown that a small proportion of indigenous E. coli is able to inhibit in vitro growth of a pathogenic E. coli strain in pigs. Furthermore, healthy animals possess significantly more inhibitory E. coli strains than diarrhoeic animals. The inhibition of pathogenic E. coli by specific indigenous E. coli strains may be an underlying principle for the containment of pathogenic

  10. Synergistic effect of eugenol with Colistin against clinical isolated Colistin-resistant Escherichia coli strains

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    Yi-ming Wang

    2018-01-01

    Full Text Available Abstract Background Bacterial infections have become more challenging to treat due to the emergence of multidrug-resistant pathogenic bacteria. Combined antibiotics prove to be a relatively effective method to control such resistant strains. This study aim to investigate synergistic activity of eugenol combined with colistin against a collection of clinical isolated Escherichia coli (E.coli strains, and to evaluate potential interaction. Methods Antimicrobial susceptibility, minimum inhibitory concentration (MIC and fractional inhibitory concentration index (FICI of the bacteria were determined by disk diffusion assay, broth microdilution method and checkerboard assay, respectively. The mcr-1 mRNA expression was measured by Real-time PCR. To predict possible interactions between eugenol and MCR-1, molecular docking assay was taken. Results For total fourteen strains including eight colistin-resistant strains, eugenol was determined with MIC values of 4 to 8 μg/mL. Checkerboard dilution test suggested that eugenol exhibited synergistic activity when combined with colistin (FICI ranging from 0.375 to 0.625. Comparison analysis of Real-time PCR showed that synergy could significantly down-regulate expression of mcr-1 gene. A metal ion coordination bond with catalytic zinc atom and a hydrogen bond with crucial amino acid residue Ser284 of MCR-1 were observed after molecular docking, indicating antibacterial activity and direct molecular interactions of eugenol with MCR-1 protein. Conclusions Our results demonstrated that eugenol exhibited synergistic effect with colistin and enhanced its antimicrobial activity. This might further contribute to the antibacterial actions against colistin-resistant E.coli strains. Graphical abstract Synergistic effect of eugenol with colistin against colistin-resistant Escherichia coli isolates.

  11. Pravastatin-induced improvement in coronary reactivity and circulating ATP and ADP levels in young adults with type 1 diabetes

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    Tuomas Oskari Kiviniemi

    2012-08-01

    Full Text Available Aims: Extracellular ATP and ADP regulate diverse inflammatory, prothrombotic and vasoactive responses in the vasculature. Statins have been shown to modulate their signaling pathways in vitro. We hypothesized that altered intravascular nucleotide turnover modulates vasodilation in patients with type 1 diabetes (T1DM, and this can be partly restored with pravastatin therapy. Methods: In this randomized double blind study, plasma ATP and ADP levels and echocardiography-derived coronary flow velocity response to cold pressor test (CPT were concurrently assessed in 42 normocholesterolemic patients with T1DM (age 30±6 years, LDL cholesterol 2.5±0.6 mmol/L before and after four-month treatment with pravastatin 40 mg/day or placebo (n=22 and n=20, respectively, and in 41 healthy control subjects. Results: Compared to controls, T1DM patients had significantly higher concentrations of ATP (p<0.01 and ADP (p<0.01 and these levels were partly restored after treatment with pravastatin (p=0.002 and p=0.007, respectively, but not after placebo (p=0.06 and p=0.14, respectively. Coronary flow velocity acceleration was significantly lower in T1DM patients compared to control subjects, and it increased from pre- to post-intervention in the pravastatin (p=0.02, but not in placebo group (p=0.15. Conclusions: Pravastatin treatment significantly reduces circulating ATP and ADP levels of T1DM patients, and concurrently improves coronary flow response to CPT. This study provides a novel insight in purinergic mechanisms involved in pleiotropic effects of pravastatin.

  12. Integration of FBG Strain Sensors in WDM Networks, Effects on Quality Factor

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    Ali Al-Lawati

    2009-06-01

    Full Text Available A study of the effect of integrating an FBG sensor in a four wavelength WDM communications system operating at 1550 nm is presented. The simulations considered focus on the mutual effects of both the sensing and the communications systems. The effect of power levels of the interrogating optical source on the performance of the two systems is also investigated under excitation levels of up to 10 dBm. The network layout used in the simulations is based on an actual optical link in Oman having a variety of spans. The results obtained at data rates of 2.5 and 10 Gbps with variable strains up to ±600 μs show a good tolerance in terms of quality of transmission for the two systems. However, the greater the strain values, the more noticeable are the degradations of transmission quality parameters of the communications system.

  13. Strain and localization effects in InGaAs(N) quantum wells: Tuning the magnetic response

    Energy Technology Data Exchange (ETDEWEB)

    Lopes-Oliveira, V., E-mail: lopes@df.ufscar.br; Herval, L. K. S.; Orsi Gordo, V.; Cesar, D. F.; Godoy, M. P. F. de; Galvão Gobato, Y. [Departamento de Física, Universidade Federal de São Carlos, 13565-905, São Carlos, São Paulo (Brazil); Henini, M. [School of Physics and Astronomy, Nottingham Nanotechnology and Nanoscience Centre, University of Nottingham, NG7 2RD Nottingham (United Kingdom); Khatab, A. [School of Physics and Astronomy, Nottingham Nanotechnology and Nanoscience Centre, University of Nottingham, NG7 2RD Nottingham (United Kingdom); National Institute of Laser Enhanced Sciences, Cairo University (Egypt); Sadeghi, M.; Wang, S. [Photonics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, 41296 Goteborg (Sweden); Schmidbauer, M. [Leibniz-Institute for Crystal Growth, Max-Born-Str. 2, D-12489 Berlin (Germany)

    2014-12-21

    We investigated effects of localization and strain on the optical and magneto-optical properties of diluted nitrogen III–V quantum wells theoretically and experimentally. High-resolution x-ray diffraction, photoluminescence (PL), and magneto-PL measurements under high magnetic fields up to 15 T were performed at low temperatures. Bir-Pikus Hamiltonian formalism was used to study the influence of strain, confinement, and localization effects. The circularly polarized magneto-PL was interpreted considering localization aspects in the valence band ground state. An anomalous behavior of the electron-hole pair magnetic shift was observed at low magnetic fields, ascribed to the increase in the exciton reduced mass due to the negative effective mass of the valence band ground state.

  14. The in vitro screening of aromatic amides as potential inhibitors of poly (ADP-ribose) polymerase

    International Nuclear Information System (INIS)

    Brown, D.M.; Horsman, M.R.; Lee, W.W.; Brown, J.M.

    1984-01-01

    It is now well established that the chromosomal enzyme poly (ADP-ribose) polymerase (ADPRP) is involved in the repair of DNA damage caused by ionizing radiation and alkylating agents, although the mechanisms involved are still not clear. ADPRP inhibitors include thymidine, nicotinamides, benzamides and methyl xanthines. The authors have demonstrated that these compounds are effective inhibitors of X-ray-induced potentially lethal damage repair (PLDR). More recently, they have shown that the cytotoxicity of the bifunctional alkylating L-phenylalanine mustard (L-PAM) was enhanced in vitro and in vivo by 3-aminobenzamide, nicotinamide and caffeine, although in the latter case pharmacokinetic changes could have contributed to the enhanced killing. The authors have examined a series of substituted carbocyclic and heterocyclic aromatic amides as potential inhibitors of ADPRP. The effect of these compounds on ADPRP activity in vitro as well as their effect on the repair of X-ray and alkylation damage in vitro are presented

  15. Antagonistic effect of Lactobacillus strains against gas-producing coliforms isolated from colicky infants

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    Oggero Roberto

    2011-06-01

    Full Text Available Abstract Background Infantile colic is a common disturb within the first 3 months of life, nevertheless the pathogenesis is incompletely understood and treatment remains an open issue. Intestinal gas production is thought to be one of the causes of abdominal discomfort in infants suffering from colic. However, data about the role of the amount of gas produced by infants' colonic microbiota and the correlation with the onset of colic symptoms are scanty. The benefit of supplementation with lactobacilli been recently reported but the mechanisms by which they exert their effects have not yet been fully defined. This study was performed to evaluate the interaction between Lactobacillus spp. strains and gas-forming coliforms isolated from stools of colicky infants. Results Strains of coliforms were isolated from stools of 45 colicky and 42 control breastfed infants in McConkey Agar and identified using PCR with species-specific primers, and the BBL™ Enterotube™ II system for Enterobacteriaceae. Gas-forming capability of coliforms was assessed in liquid cultures containing lactose as sole carbon source. The average count of total coliforms in colicky infants was significantly higher than controls: 5.98 (2.00-8.76 log10 vs 3.90 (2.50-7.10 CFU/g of faeces (p = 0.015. The following strains were identified: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Enterobacter cloacae and Enterococcus faecalis. Then, 27 Lactobacillus strains were tested for their antagonistic effect against coliforms both by halo-forming method and in liquid co-cultures. Lactobacillus delbrueckii subsp.delbrueckii DSM 20074 and L. plantarum MB 456 were able to inhibit all coliforms strains (halo-forming method, also in liquid co-cultures, thus demonstrating an antagonistic activity. Conclusions This study shows that two out of 27 strains of Lactobacillus examined possess an antimicrobial effect against six species of gas-forming coliforms

  16. Effects of NS lactobacillus strains on lipid metabolism of rats fed a high-cholesterol diet

    Science.gov (United States)

    2013-01-01

    Background Elevated serum cholesterol level is generally considered to be a risk factor for the development of cardiovascular diseases which seriously threaten human health. The cholesterol-lowering effects of lactic acid bacteria have recently become an area of great interest and controversy for many researchers. In this study, we investigated the effects of two NS lactobacillus strains, Lactobacillus plantarum NS5 and Lactobacillus delbrueckii subsp. bulgaricus NS12, on lipid metabolism of rats fed a high cholesterol diet. Methods Thirty-two SD rats were assigned to four groups and fed either a normal or a high-cholesterol diet. The NS lactobacillus treated groups received the high-cholesterol diet supplemented with Lactobacillus plantarum NS5 or Lactobacillus delbrueckii subsp. bulgaricus NS12 in drinking water. The rats were sacrificed after a 6-week feeding period. Body weights, visceral organ and fat weights, serum and liver cholesterol and lipid levels, intestinal microbiota and liver mRNA expression levels related to cholesterol metabolism were analyzed. Liver lipid deposition and adipocyte size were evaluated histologically. Results Compared with rats fed a high cholesterol diet, serum total cholesterol, low-density lipoprotein cholesterol, apolipoprotein B and free fatty acids levels were decreased and apolipoprotein A-I level was increased in NS5 or NS12 strain treated rats, and with no significant change in high-density lipoprotein cholesterol level. Liver cholesterol and triglyceride levels were also significantly decreased in NS lactobacillus strains treated groups. Meanwhile, the NS lactobacillus strains obviously alleviated hepatic injuries, decreased liver lipid deposition and reduced adipocyte size of high cholesterol diet fed rats. NS lactobacillus strains restored the changes in intestinal microbiota compositions, such as the increase in Bacteroides and the decrease in Clostridium. NS lactobacillus strains also regulated the mRNA expression

  17. Antagonistic effect of Lactobacillus strains against gas-producing coliforms isolated from colicky infants.

    Science.gov (United States)

    Savino, Francesco; Cordisco, Lisa; Tarasco, Valentina; Locatelli, Emanuela; Di Gioia, Diana; Oggero, Roberto; Matteuzzi, Diego

    2011-06-30

    Infantile colic is a common disturb within the first 3 months of life, nevertheless the pathogenesis is incompletely understood and treatment remains an open issue. Intestinal gas production is thought to be one of the causes of abdominal discomfort in infants suffering from colic. However, data about the role of the amount of gas produced by infants' colonic microbiota and the correlation with the onset of colic symptoms are scanty. The benefit of supplementation with lactobacilli been recently reported but the mechanisms by which they exert their effects have not yet been fully defined. This study was performed to evaluate the interaction between Lactobacillus spp. strains and gas-forming coliforms isolated from stools of colicky infants. Strains of coliforms were isolated from stools of 45 colicky and 42 control breastfed infants in McConkey Agar and identified using PCR with species-specific primers, and the BBL™ Enterotube™ II system for Enterobacteriaceae. Gas-forming capability of coliforms was assessed in liquid cultures containing lactose as sole carbon source. The average count of total coliforms in colicky infants was significantly higher than controls: 5.98 (2.00-8.76) log10 vs 3.90 (2.50-7.10) CFU/g of faeces (p = 0.015). The following strains were identified: Escherichia coli, Klebsiella pneumoniae, Klebsiella oxytoca, Enterobacter aerogenes, Enterobacter cloacae and Enterococcus faecalis. Then, 27 Lactobacillus strains were tested for their antagonistic effect against coliforms both by halo-forming method and in liquid co-cultures. Lactobacillus delbrueckii subsp. delbrueckii DSM 20074 and L. plantarum MB 456 were able to inhibit all coliforms strains (halo-forming method), also in liquid co-cultures, thus demonstrating an antagonistic activity. This study shows that two out of 27 strains of Lactobacillus examined possess an antimicrobial effect against six species of gas-forming coliforms isolated from colicky infants. Our findings may stimulate

  18. Correlation between increased platelet ADP aggregability and silent brain infarcts

    International Nuclear Information System (INIS)

    Ono, Kenichiro; Arimoto, Hirohiko; Shirotani, Toshiki

    2012-01-01

    The purpose of this study was to investigate the correlation between platelet aggregability and silent brain infarcts. The study subjects were 445 people (264 men, 181 women; mean age, 53±14 years) with no neurologic signs, history of brain tumor, trauma, cerebrovascular disease, or antiplatelet medications. Adenosine diphosphate (ADP)-induced platelet aggregation was measured by the aggregation-size analytic method. Platelet aggregability was classified into 9 classes. The presence of headache/vertigo, hypertension, diabetes mellitus, hyperlipidemia, or smoking was elicited by questioning or blood sampling. A head MRI scan was performed, and if marked atherosclerosis or obvious stenosis in the intracranial vessels was detected, it was defined as a positive MR angiography (MRA) finding. Silent brain infarcts were detected in 26.3% of subjects. Hyperaggregability defined as that above class 6, 7, and 8 was present in 43.8%, 30.8%, and 15.7% of subjects, respectively. The risk factors for silent brain infarcts by multiple logistic regression analysis were aging, hypertension, positive MRA findings, and hyperaggregability. Platelet ADP hyperaggregability might be a risk factor for silent brain infarcts. (author)

  19. Effect of Dynamic Change in Strain Rate on Mechanical and Stress Corrosion Cracking Behavior of a Mild Steel

    Science.gov (United States)

    Krishnan, Govinda; Varshney, A.; Parameswaran, Venkitanarayanan; Mondal, K.

    2017-05-01

    The current work analyzes the effect of the dynamic change in strain rate during tensile loading of a mild steel on its mechanical and stress corrosion behavior in 3.5 wt.% NaCl solution. The sample experiences high strain rate (10-2 s-1) up to 10, 15 and 20% of total deformation and then very low strain rate of 10-6 s-1 till fracture without any unloading in between. The behavioral characteristics of the steel under these circumstances are found to be different from that exhibited during complete loading till fracture both at high and slow strain rates separately. Total strain increases with the increase in the strain at which change in strain rate happens, and this is attributed to the generation of large number of dislocations at higher strain rate and subsequently release of dislocation at low strain rate during change over due to more time available for dynamic recovery. This observation is common for both in air and corrosive environment. One unique observation in this study is the higher total strain and lower strength observed during dynamic change in strain rate in the corrosive environment compared to that in air, which is attributed to the hydrogen-induced plasticity mechanism.

  20. Tensile strain effect in ferroelectric perovskite oxide thin films on spinel magnesium aluminum oxide substrate

    Science.gov (United States)

    Zhou, Xiaolan

    Ferroelectrics are used in FeRAM (Ferroelectric random-access memory). Currently (Pb,Zr)TiO3 is the most common ferroelectric material. To get lead-free and high performance ferroelectric material, we investigated perovskite ferroelectric oxides (Ba,Sr)TiO3 and BiFeO3 films with strain. Compressive strain has been investigated intensively, but the effects of tensile strain on the perovskite films have yet to be explored. We have deposited (Ba,Sr)TiO3, BiFeO3 and related films by pulsed laser deposition (PLD) and analyzed the films by X-ray diffractometry (XRD), atomic force microscopy (AFM), etc. To obtain inherently fully strained films, the selection of the appropriate substrates is crucial. MgAl2O4 matches best with good quality and size, yet the spinel structure has an intrinsic incompatibility to that of perovskite. We introduced a rock-salt structure material (Ni 1-xAlxO1+delta) as a buffer layer to mediate the structural mismatch for (Ba,Sr)TiO3 films. With buffer layer Ni1-xAlxO1+delta, we show that the BST films have high quality crystallization and are coherently epitaxial. AFM images show that the films have smoother surfaces when including the buffer layer, indicating an inherent compatibility between BST-NAO and NAO-MAO. In-plane Ferroelectricity measurement shows double hysteresis loops, indicating an antiferroelectric-like behavior: pinned ferroelectric domains with antiparallel alignments of polarization. The Curie temperatures of the coherent fully strained BST films are also measured. It is higher than 900°C, at least 800°C higher than that of bulk. The improved Curie temperature makes the use of BST as FeRAM feasible. We found that the special behaviors of ferroelectricity including hysteresis loop and Curie temperature are due to inherent fully tensile strain. This might be a clue of physics inside ferroelectric stain engineering. An out-of-plane ferroelectricity measurement would provide a full whole story of the tensile strain. However, a

  1. Plant secondary metabolite profiling evidences strain-dependent effect in the Azospirillum-Oryza sativa association.

    Science.gov (United States)

    Chamam, Amel; Sanguin, Hervé; Bellvert, Floriant; Meiffren, Guillaume; Comte, Gilles; Wisniewski-Dyé, Florence; Bertrand, Cédric; Prigent-Combaret, Claire

    2013-03-01

    Azospirillum is a plant growth-promoting rhizobacterium (PGPR) able to enhance growth and yield of cereals such as rice, maize and wheat. The growth-promoting ability of some Azospirillum strains appears to be highly specific to certain plant species and cultivars. In order to ascertain the specificity of the associative symbiosis between rice and Azospirillum, the physiological response of two rice cultivars, Nipponbare and Cigalon, inoculated with two rice-associated Azospirillum was analyzed at two levels: plant growth response and plant secondary metabolic response. Each strain of Azospirillum (Azospirillum lipoferum 4B isolated from Cigalon and Azospirillum sp. B510 isolated from Nipponbare) preferentially increased growth of the cultivar from which it was isolated. This specific effect is not related to a defect in colonization of host cultivar as each strain colonizes effectively both rice cultivars, either at the rhizoplane (for 4B and B510) and inside the roots (for B510). The metabolic profiling approach showed that, in response to PGPR inoculation, profiles of rice secondary metabolites were modified, with phenolic compounds such as flavonoids and hydroxycinnamic derivatives being the main metabolites affected. Moreover, plant metabolic changes differed according to Azospirillum strain×cultivar combinations; indeed, 4B induced major secondary metabolic profile modifications only on Cigalon roots, while B510, probably due to its endophytic feature, induced metabolic variations on shoots and roots of both cultivars, triggering a systemic response. Plant secondary metabolite profiling thereby evidences the specific interaction between an Azospirillum strain and its original host cultivar. Copyright © 2012 Elsevier Ltd. All rights reserved.

  2. Effects of Participation in Support Groups on Alzheimer’s Family Caregivers’ Strain and Spiritual Wellbeing

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    Farahnaz Mohammadi

    2011-04-01

    Full Text Available Objectives: Since support for family caregivers is crucial in providing care for elderly, this study was conducted to examine the effects of participation in support groups on Alzheimer’s family caregivers’ strain and spiritual wellbeing. Materials and Methods & Materials: In this semi-experimental study, 32 accessible family caregivers of elderly patients with Alzheimer who had at least one year of experience participated. The intervention consisted of a 4-month active participation in educational and emotional supportive sessions related to patient and caregivers care management. At the end of the intervention, the leadership of the groups was transferred to members of the groups. These sessions were conducted in 3 public centers in the community. Caregivers were assessed by caregiving strain and spiritual wellbeing questionnaires at the beginning, at the end of the intervention and 2 months later. Data was analyzed by ANOVA with repeated measurement. P<0.05 was considered statistically significant. Results: In general, 32 accessible family caregivers of elderly Alzheimer patients with at least one year of experience participated in this study. The mean of spiritual wellbeing through three mentioned measurements showed an improvement (26.029, 34.029, 34.471, whereas the care giving strain showed a decreasing trend (40.118, 32.706, 31.265. Findings based on ANOVA-repeated measurement revealed a significantly decrease in care giving strain (P=0.001 and an improvement in spiritual wellbeing (P=0.005. Conclusion: Participation in the support groups as a manifest of empowering helps family caregivers to deal effectively with care giving difficulties. Psychoeducational programs lead to a decreased care giving strain and improve the spiritual wellbeing of the caregivers. Hence, supportive interventions should be considered by policy makers and professional health care providers for elderly people.

  3. Absence of strong strain effects in behavioral analyses of Shank3-deficient mice

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    Elodie Drapeau

    2014-06-01

    Full Text Available Haploinsufficiency of SHANK3, caused by chromosomal abnormalities or mutations that disrupt one copy of the gene, leads to a neurodevelopmental syndrome called Phelan-McDermid syndrome, symptoms of which can include absent or delayed speech, intellectual disability, neurological changes and autism spectrum disorders. The SHANK3 protein forms a key structural part of the post-synaptic density. We previously generated and characterized mice with a targeted disruption of Shank3 in which exons coding for the ankyrin-repeat domain were deleted and expression of full-length Shank3 was disrupted. We documented specific deficits in synaptic function and plasticity, along with reduced reciprocal social interactions, in Shank3 heterozygous mice. Changes in phenotype owing to a mutation at a single locus are quite frequently modulated by other loci, most dramatically when the entire genetic background is changed. In mice, each strain of laboratory mouse represents a distinct genetic background and alterations in phenotype owing to gene knockout or transgenesis are frequently different across strains, which can lead to the identification of important modifier loci. We have investigated the effect of genetic background on phenotypes of Shank3 heterozygous, knockout and wild-type mice, using C57BL/6, 129SVE and FVB/Ntac strain backgrounds. We focused on observable behaviors with the goal of carrying out subsequent analyses to identify modifier loci. Surprisingly, there were very modest strain effects over a large battery of analyses. These results indicate that behavioral phenotypes associated with Shank3 haploinsufficiency are largely strain-independent.

  4. The effects of temperature and use of vibrating wire strain gauges for braced excavations

    Energy Technology Data Exchange (ETDEWEB)

    Boone, S. J. [Golder Associates, Irvine, CA (United States); Crawford, A. M. [Toronto Univ., ON (Canada). Dept. of Civil Engineering

    2000-09-01

    Strut loads in bracer excavations are routinely monitored with strain gauges which range in complexity from simple mechanical measurements to vibrating wire transducers. While in soft soils the effect of temperature changes in strut loads may not be significant, these effects may be very signifciant for stiff and dense soils and rock thermal loading, where inadequate appreciation of the role played by thermal laods may lead to misinterpretations and faulty design that is not representative of potential field loading. This paper interprets the theoretical and practical implications of temperature change on strut loads and discusses the relative merits of using a vibrating wire strain gauge to measure and evaluate the effects of temperature and earth loads. It is shown that by comparing the incremental changes of strut load and temperature from vibrating wire strain gauge data, the temperature-dependent loads, the relative fixity of the strut end, and the earth loads, and mobilized ground stiffness can be deduced. The approach proposed provides a transparent and strut-specific means of evaluating the effects of temperature on struts with braced excavations and is supported by both empirical data and practical application of elastic theory. 9 refs., 6 figs.

  5. Effect of Agave tequilana age, cultivation field location and yeast strain on tequila fermentation process.

    Science.gov (United States)

    Pinal, L; Cornejo, E; Arellano, M; Herrera, E; Nuñez, L; Arrizon, J; Gschaedler, A

    2009-05-01

    The effect of yeast strain, the agave age and the cultivation field location of agave were evaluated using kinetic parameters and volatile compound production in the tequila fermentation process. Fermentations were carried out with Agave juice obtained from two cultivation fields (CF1 and CF2), as well as two ages (4 and 8 years) and two Saccharomyces cerevisiae yeast strains (GU3 and AR5) isolated from tequila fermentation must. Sugar consumption and ethanol production varied as a function of cultivation field and agave age. The production of ethyl acetate, 1-propanol, isobutanol and amyl alcohols were influenced in varying degrees by yeast strain, agave age and cultivation field. Methanol production was only affected by the agave age and 2-phenylethanol was influenced only by yeast strain. This work showed that the use of younger Agave tequilana for tequila fermentation resulted in differences in sugar consumption, ethanol and volatile compounds production at the end of fermentation, which could affect the sensory quality of the final product.

  6. Effectiveness and competing capacity of native Rhizobium strains evaluated in IX Region soils

    International Nuclear Information System (INIS)

    Barrientos D, Leticia; Mendez A, Edith; Pino N, Ines

    1995-01-01

    Symbiotic nitrogen fixation in legumes reaches its optimum when the host plants are nodulated by highly competitive and effective Rhizobium strains. With the purpose of assessing competition and nitrogen fixing capacity of native Rhizobium leguminosarum bio-var trifolii strains, a greenhouse test was carried out using white clover (Trifolium re-pens) and four kinds of soils, which represent the main agroecological areas of the IX Region. Eleven strains were evaluated, they were both native and collected and were streptomycin sulphate antibiotic resistant. A nitrogen and a nitrogen-less without inoculation testers were used as controls. All pots received a solution of ammonium sulphate marked with 10% 15 N a.e, equivalent to 10 kg ha -1 of N. Rye-grass was used as reference crop, cv. Nu-i. In general, the evaluated strains were very efficient. After three or four cuts they became the only source of nitrogen for the plants. They were also very competitive, getting to over 70% of root infection with regard to those present in soils. In Curacautin and Tolten soils, biological nitrogen fixation begins later than other soils evaluated, which is coincident with soils having a higher nitrogen content. Symbiosis occurs when the soil nitrogen content exhausts or diminishes. (author)

  7. Tension–compression asymmetry in an extruded Mg alloy AM30: Temperature and strain rate effects

    International Nuclear Information System (INIS)

    Zachariah, Z.; Tatiparti, Sankara Sarma V.; Mishra, S.K.; Ramakrishnan, N.; Ramamurty, U.

    2013-01-01

    The effect of strain rate, ε, and temperature, T, on the tension–compression asymmetry (TCA) in a dilute and wrought Mg alloy, AM30, over a temperature range that covers both twin accommodated deformation (below 250 °C in compression) as well as dislocation-mediated plasticity (above 250 °C) has been investigated. For this purpose, uniaxial tension and compression tests were conducted at T ranging from 25 to 400 °C with ε varying between 10 −2 and 10 s −1 . In most of the cases, the stress–strain responses in tension and compression are distinctly different; with compression responses ‘concaving upward,’ due to {101-bar 2} tensile twinning at lower plastic strains followed by slip and strain hardening at higher levels of deformation, for T below 250 °C. This results in significant levels of TCA at T −1 , suggesting that twin-mediated plastic deformation takes precedence at high rates of loading even at sufficiently high T. TCA becomes negligible at T=350 °C; however at T=400 °C, as ε increases TCA gets higher. Microscopy of the deformed samples, carried out by using electron back-scattered diffraction (EBSD), suggests that at T>250 °C dynamic recrystallization begins between accompanied by reduction in the twinned fraction that contributes to the decrease of the TCA

  8. Dynamic strain-induced giant electroresistance and erasing effect in ultrathin ferroelectric tunnel-junction memory

    Science.gov (United States)

    Yau, Hei-Man; Xi, Zhongnan; Chen, Xinxin; Wen, Zheng; Wu, Ge; Dai, Ji-Yan

    2017-06-01

    Strain engineering plays a critical role in ferroelectric memories. In this work, we demonstrate dynamic strain modulation on tunneling electroresistance in a four-unit-cell ultrathin BaTi O3 metal/ferroelectric/semiconductor tunnel junction by applying mechanical stress to the device. With an extra compressive strain induced by mechanical stress, which is dynamically applied beyond the lattice mismatch between the BaTi O3 layer and the Nb :SrTi O3 substrate, the ON/OFF current ratio increases significantly up to a record high value of 107, whereas a mechanical erasing effect can be observed when a tensile stress is applied. This dynamic strain engineering gives rise to an efficient modulation of ON/OFF ratio due to the variation of BaTi O3 polarization. This result sheds light on the mechanism of electroresistance in the ferroelectric tunnel junctions by providing direct evidence for polarization-induced resistive switching, and also provides another stimulus for memory state operation.

  9. Effects of paraquat on Escherichia coli: Differences between B and K-12 strains

    International Nuclear Information System (INIS)

    Kitzler, J.W.; Minakami, H.; Fridovich, I.

    1990-01-01

    Escherichia coli B and K-12 are equally susceptible to the bacteriostatic effects of aerobic paraquat, but they differed strikingly when the lethality of paraquat was evaluated. E. coli B suffered an apparent loss of viability when briefly exposed to paraquat, whereas E. coli K-12 did not. This difference depended on the ability of the B-strain, but not the K-12 strain, to retain internalized paraquat; the B strain was killed on aerobic tryptic soy-yeast extract plates during the incubation which preceded the counting of colonies. This difference in retention of paraquat between strains was demonstrated by delayed loss of viability, by growth inhibition, and by cyanide-resistant respiration after brief exposure to paraquat, washing, and testing in fresh medium. This difference was also shown by using [ 14 C]paraquat. This previously unrecognized difference between E. coli B and K-12 has been the cause of apparently contradictory reports and should lead to some reevaluation of the pertinent literature

  10. Conditionally positive effect of the TetR-family transcriptional regulator AtrA on streptomycin production by Streptomyces griseus.

    Science.gov (United States)

    Hirano, Setsu; Tanaka, Katsuyuki; Ohnishi, Yasuo; Horinouchi, Sueharu

    2008-03-01

    AtrA, a transcriptional activator for actII-ORF4, encoding the pathway-specific transcriptional activator of the actinorhodin biosynthetic gene cluster in Streptomyces coelicolor A3(2), has been shown to bind the region upstream from the promoter of strR, encoding the pathway-specific transcriptional activator of the streptomycin biosynthetic gene cluster in Streptomyces griseus [Uguru et al. (2005) Mol Microbiol 58, 131-150]. The atrA orthologue (atrA-g) in S. griseus was constitutively transcribed throughout growth from a promoter located about 250 nt upstream of the translational start codon, as determined by S1 nuclease mapping. DNase I footprinting showed that histidine-tagged AtrA-g bound an inverted repeat located upstream of strR at positions -117 to -142 relative to the transcriptional start point of strR as +1. This AtrA-g-binding site was between two AdpA-binding sites at approximately nucleotide positions -270 and -50. AdpA is a central transcriptional activator in the A-factor regulatory cascade and essential for the transcription of strR. AtrA-g and AdpA simultaneously bound the respective binding sites. In contrast to AdpA, AtrA-g was non-essential for strR transcription; an atrA-g-disrupted strain produced streptomycin on routine agar media to the same extent as the wild-type strain. However, the atrA-g-disrupted strain tended to produce a smaller amount of streptomycin than the wild-type strain under some conditions, for example, on Bennett agar containing 1 % maltose and on a minimal medium. Therefore, AtrA-g had a conditionally positive effect on streptomycin production, as a tuner, probably by enhancing the AdpA-dependent transcriptional activation of strR in a still unknown manner.

  11. Effect of wavelength-dependent attenuation on strain measurement using pulsed neutron diffraction

    International Nuclear Information System (INIS)

    Wang, D.-Q.; Santisteban, J.R.; Edwards, L.

    2001-01-01

    The measurement of stresses in engineering components and structures by neutron diffraction has traditionally been limited to depths of a few centimetres. However, recent developments in instrumentation open up the possibility of deeper measurements. It has been suggested that a systematic error may occur when measuring stresses deep in materials due to wavelength-dependent attenuation of the incident and/or diffracted beam. A series of experiments to evaluate the magnitude of this effect on ENGIN, a pulsed neutron strain scanner will be presented in this paper. It was found that the pseudo-strains induced by the attenuation of the diffracted beam were negligible, whereas there was a small but still noticeable effect produced by the attenuation in the incident beam. The possible causes of this shift and the consequences for deep measurements are discussed

  12. Effect of wavelength-dependent attenuation on strain measurement using pulsed neutron diffraction

    CERN Document Server

    Wang, D Q; Edwards, L

    2001-01-01

    The measurement of stresses in engineering components and structures by neutron diffraction has traditionally been limited to depths of a few centimetres. However, recent developments in instrumentation open up the possibility of deeper measurements. It has been suggested that a systematic error may occur when measuring stresses deep in materials due to wavelength-dependent attenuation of the incident and/or diffracted beam. A series of experiments to evaluate the magnitude of this effect on ENGIN, a pulsed neutron strain scanner will be presented in this paper. It was found that the pseudo-strains induced by the attenuation of the diffracted beam were negligible, whereas there was a small but still noticeable effect produced by the attenuation in the incident beam. The possible causes of this shift and the consequences for deep measurements are discussed.

  13. The Role of Poly(ADP-ribose Polymerase-1 in Rheumatoid Arthritis

    Directory of Open Access Journals (Sweden)

    Samuel García

    2015-01-01

    Full Text Available Poly(ADP-ribose polymerase-1 (PARP-1 is a nuclear enzyme with a crucial role in the maintenance of genomic stability. In addition to the role of PARP-1 in DNA repair, multiple studies have also demonstrated its involvement in several inflammatory diseases, such as septic shock, asthma, atherosclerosis, and stroke, as well as in cancer. In these diseases, the pharmacological inhibition of PARP-1 has shown a beneficial effect, suggesting that PARP-1 regulates their inflammatory processes. In recent years, we have studied the role of PARP-1 in rheumatoid arthritis, as have other researchers, and the results have shown that PARP-1 has an important function in the development of this disease. This review summarizes current knowledge on the effects of PARP-1 in rheumatoid arthritis.

  14. Poly (ADP-Ribose) Polymerase is Involved in the Repair of DNA Damage Due to Sulfur Mustard by a Mechanism Other Than DNA Ligase I Activation

    National Research Council Canada - National Science Library

    Bhat, K. Ramachandra; Benton, Betty J; Ray, Radharaman

    2004-01-01

    Poly (ADP-ribose) polymerase (PARP) modulates several cellular functional proteins by a mechanism in which the proteins are poly-ADP-ribosylated by transferring the ADP-ribose moieties from the enzyme substrate NAD+ to the proteins...

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    Full Text Available Oth.Adp.20.AllAg.Brown_adipocytes mm9 TFs and others Adipocyte Brown adipocytes SRX...RX978689,SRX800015,SRX800014,SRX800018,SRX800019 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Adp.20.AllAg.Brown_adipocytes.bed ...

  11. File list: NoD.Adp.05.AllAg.White_adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Adp.05.AllAg.White_adipocytes mm9 No description Adipocyte White adipocytes htt...p://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Adp.05.AllAg.White_adipocytes.bed ...

  12. File list: ALL.Adp.20.AllAg.Adipose_Tissue [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Adp.20.AllAg.Adipose_Tissue hg19 All antigens Adipocyte Adipose Tissue SRX13473...2 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Adp.20.AllAg.Adipose_Tissue.bed ...

  13. File list: Pol.Adp.05.AllAg.Adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Adp.05.AllAg.Adipocytes hg19 RNA polymerase Adipocyte Adipocytes SRX682086,SRX6...82084,SRX682083,SRX682085 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Adp.05.AllAg.Adipocytes.bed ...

  14. File list: DNS.Adp.20.AllAg.Adipose_stromal_cell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Adp.20.AllAg.Adipose_stromal_cell hg19 DNase-seq Adipocyte Adipose stromal cell... http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Adp.20.AllAg.Adipose_stromal_cell.bed ...

  15. File list: ALL.Adp.50.AllAg.Adipose_Tissue [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Adp.50.AllAg.Adipose_Tissue hg19 All antigens Adipocyte Adipose Tissue SRX13473...2 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Adp.50.AllAg.Adipose_Tissue.bed ...

  16. File list: ALL.Adp.50.AllAg.Adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Adp.50.AllAg.Adipocytes hg19 All antigens Adipocyte Adipocytes SRX682084,SRX682...086,SRX027402,SRX682085,SRX682083,SRX027401,SRX027400,SRX027404,SRX027403 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Adp.50.AllAg.Adipocytes.bed ...

  17. File list: His.Adp.50.AllAg.Pre-adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adp.50.AllAg.Pre-adipocytes hg19 Histone Adipocyte Pre-adipocytes SRX760966,SRX...760964,SRX760963,SRX760965,SRX760962 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Adp.50.AllAg.Pre-adipocytes.bed ...

  18. File list: NoD.Adp.20.AllAg.Adipose_Tissue [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Adp.20.AllAg.Adipose_Tissue hg19 No description Adipocyte Adipose Tissue SRX134...732 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Adp.20.AllAg.Adipose_Tissue.bed ...

  19. File list: Oth.Adp.50.AllAg.Brown_preadipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Adp.50.AllAg.Brown_preadipocytes mm9 TFs and others Adipocyte Brown preadipocyt...341028,SRX341760,SRX341767,SRX341763,SRX341027 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Adp.50.AllAg.Brown_preadipocytes.bed ...

  20. File list: NoD.Adp.05.AllAg.Adipose_Tissue [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Adp.05.AllAg.Adipose_Tissue hg19 No description Adipocyte Adipose Tissue SRX134...732 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Adp.05.AllAg.Adipose_Tissue.bed ...

  1. File list: Pol.Adp.10.AllAg.Adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Adp.10.AllAg.Adipocytes hg19 RNA polymerase Adipocyte Adipocytes SRX682086,SRX6...82084,SRX682085,SRX682083 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Adp.10.AllAg.Adipocytes.bed ...

  2. File list: Oth.Adp.10.AllAg.Pre-adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Adp.10.AllAg.Pre-adipocytes hg19 TFs and others Adipocyte Pre-adipocytes SRX760...968,SRX760967,SRX760971,SRX760969,SRX760970 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Adp.10.AllAg.Pre-adipocytes.bed ...

  3. File list: NoD.Adp.50.AllAg.Adipose_Tissue [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Adp.50.AllAg.Adipose_Tissue hg19 No description Adipocyte Adipose Tissue SRX134...732 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Adp.50.AllAg.Adipose_Tissue.bed ...

  4. File list: NoD.Adp.10.AllAg.Adipose_Tissue [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Adp.10.AllAg.Adipose_Tissue hg19 No description Adipocyte Adipose Tissue SRX134...732 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Adp.10.AllAg.Adipose_Tissue.bed ...

  5. File list: InP.Adp.50.AllAg.White_adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Adp.50.AllAg.White_adipocytes mm9 Input control Adipocyte White adipocytes SRX2...68023,SRX997757,SRX821800,SRX821801,SRX821799 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Adp.50.AllAg.White_adipocytes.bed ...

  6. File list: His.Adp.05.AllAg.Capan-1 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adp.05.AllAg.Capan-1 hg19 Histone Adipocyte Capan-1 SRX825378,SRX825371,SRX825364,SRX825385 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Adp.05.AllAg.Capan-1.bed ...

  7. File list: Oth.Adp.50.AllAg.Adipose_Tissue,_White [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Adp.50.AllAg.Adipose_Tissue,_White hg19 TFs and others Adipocyte Adipose Tissue, White...SRX821810,SRX821806,SRX821809,SRX821817,SRX821816,SRX821807 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Adp.50.AllAg.Adipose_Tissue,_White.bed ...

  8. File list: Unc.Adp.20.AllAg.Adipose_Tissue,_White [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Adp.20.AllAg.Adipose_Tissue,_White hg19 Unclassified Adipocyte Adipose Tissue, White... http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Adp.20.AllAg.Adipose_Tissue,_White.bed ...

  9. File list: Pol.Adp.50.AllAg.Adipose_Tissue,_White [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Adp.50.AllAg.Adipose_Tissue,_White hg19 RNA polymerase Adipocyte Adipose Tissue, White... http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Adp.50.AllAg.Adipose_Tissue,_White.bed ...

  10. File list: Oth.Adp.20.AllAg.White_adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Adp.20.AllAg.White_adipocytes mm9 TFs and others Adipocyte White adipocytes SRX... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Adp.20.AllAg.White_adipocytes.bed ...

  11. File list: Oth.Adp.20.AllAg.Adipose_Tissue,_White [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Adp.20.AllAg.Adipose_Tissue,_White hg19 TFs and others Adipocyte Adipose Tissue, White...SRX821817,SRX821821,SRX821815,SRX821811,SRX821810,SRX821809 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Oth.Adp.20.AllAg.Adipose_Tissue,_White.bed ...

  12. File list: Oth.Adp.50.AllAg.White_adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.Adp.50.AllAg.White_adipocytes mm9 TFs and others Adipocyte White adipocytes SRX... http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.Adp.50.AllAg.White_adipocytes.bed ...

  13. File list: Pol.Adp.20.AllAg.White_adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Adp.20.AllAg.White_adipocytes mm9 RNA polymerase Adipocyte White adipocytes SRX...800011 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Adp.20.AllAg.White_adipocytes.bed ...

  14. File list: Pol.Adp.20.AllAg.Adipose_Tissue,_White [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Adp.20.AllAg.Adipose_Tissue,_White hg19 RNA polymerase Adipocyte Adipose Tissue, White... http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Adp.20.AllAg.Adipose_Tissue,_White.bed ...

  15. File list: His.Adp.50.AllAg.Adipose_Tissue,_White [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adp.50.AllAg.Adipose_Tissue,_White hg19 Histone Adipocyte Adipose Tissue, White... http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Adp.50.AllAg.Adipose_Tissue,_White.bed ...

  16. File list: Pol.Adp.50.AllAg.White_adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Adp.50.AllAg.White_adipocytes mm9 RNA polymerase Adipocyte White adipocytes SRX...800011 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Adp.50.AllAg.White_adipocytes.bed ...

  17. File list: Unc.Adp.50.AllAg.Adipose_Tissue,_White [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Unc.Adp.50.AllAg.Adipose_Tissue,_White hg19 Unclassified Adipocyte Adipose Tissue, White... http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Unc.Adp.50.AllAg.Adipose_Tissue,_White.bed ...

  18. File list: DNS.Adp.05.AllAg.Adipose_Tissue,_White [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Adp.05.AllAg.Adipose_Tissue,_White hg19 DNase-seq Adipocyte Adipose Tissue, White... http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Adp.05.AllAg.Adipose_Tissue,_White.bed ...

  19. File list: ALL.Adp.50.AllAg.Adipose_Tissue,_White [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Adp.50.AllAg.Adipose_Tissue,_White hg19 All antigens Adipocyte Adipose Tissue, White...X821810,SRX821806,SRX821809,SRX821817,SRX821816,SRX821807 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Adp.50.AllAg.Adipose_Tissue,_White.bed ...

  20. File list: ALL.Adp.05.AllAg.Adipose_Tissue,_White [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Adp.05.AllAg.Adipose_Tissue,_White hg19 All antigens Adipocyte Adipose Tissue, White...X821815,SRX821821,SRX821816,SRX821809,SRX821817,SRX821810 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Adp.05.AllAg.Adipose_Tissue,_White.bed ...

  1. File list: DNS.Adp.50.AllAg.Adipose_Tissue,_White [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Adp.50.AllAg.Adipose_Tissue,_White hg19 DNase-seq Adipocyte Adipose Tissue, White... http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Adp.50.AllAg.Adipose_Tissue,_White.bed ...

  2. File list: Pol.Adp.05.AllAg.White_adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Adp.05.AllAg.White_adipocytes mm9 RNA polymerase Adipocyte White adipocytes SRX...800011 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Adp.05.AllAg.White_adipocytes.bed ...

  3. File list: ALL.Adp.20.AllAg.Adipose_Tissue,_White [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Adp.20.AllAg.Adipose_Tissue,_White hg19 All antigens Adipocyte Adipose Tissue, White...X821817,SRX821821,SRX821815,SRX821811,SRX821810,SRX821809 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/ALL.Adp.20.AllAg.Adipose_Tissue,_White.bed ...

  4. File list: InP.Adp.05.AllAg.White_adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Adp.05.AllAg.White_adipocytes mm9 Input control Adipocyte White adipocytes SRX9...97757,SRX821800,SRX821801,SRX268023,SRX821799 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/InP.Adp.05.AllAg.White_adipocytes.bed ...

  5. File list: DNS.Adp.20.AllAg.Adipose_Tissue,_White [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available DNS.Adp.20.AllAg.Adipose_Tissue,_White hg19 DNase-seq Adipocyte Adipose Tissue, White... http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/DNS.Adp.20.AllAg.Adipose_Tissue,_White.bed ...

  6. File list: Pol.Adp.10.AllAg.White_adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Adp.10.AllAg.White_adipocytes mm9 RNA polymerase Adipocyte White adipocytes SRX...800011 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Adp.10.AllAg.White_adipocytes.bed ...

  7. NMR resonance assignments of NarE, a putative ADP-ribosylating toxin from Neisseria meningitidis

    NARCIS (Netherlands)

    Carlier, L.P.A.; Köhler, Christian; Veggi, D.; Pizza, M.; Soriani, M.; Boelens, R.; Bonvin, A.M.J.J.

    2011-01-01

    NarE is a 16 kDa protein identified from Neisseria meningitidis, one of the bacterial pathogens responsible for meningitis. NarE belongs to the ADP-ribosyltransferase family and catalyses the transfer of ADP-ribose moieties to arginine residues in target protein acceptors. Many pathogenic bacteria

  8. File list: Pol.Adp.20.RNA_polymerase_II.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Adp.20.RNA_polymerase_II.AllCell hg19 RNA polymerase RNA polymerase II Adipocyt...e SRX682084,SRX682086,SRX682083,SRX682085 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Adp.20.RNA_polymerase_II.AllCell.bed ...

  9. File list: Pol.Adp.05.RNA_polymerase_III.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Adp.05.RNA_polymerase_III.AllCell hg19 RNA polymerase RNA polymerase III Adipoc...yte http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/Pol.Adp.05.RNA_polymerase_III.AllCell.bed ...

  10. File list: Pol.Adp.50.RNA_Polymerase_II.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Pol.Adp.50.RNA_Polymerase_II.AllCell mm9 RNA polymerase RNA Polymerase II Adipocyte... SRX800011,SRX800010,SRX341031,SRX341032,SRX341029,SRX800016,SRX800017,SRX341030 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Pol.Adp.50.RNA_Polymerase_II.AllCell.bed ...

  11. File list: NoD.Adp.20.AllAg.White_adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Adp.20.AllAg.White_adipocytes mm9 No description Adipocyte White adipocytes htt...p://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/NoD.Adp.20.AllAg.White_adipocytes.bed ...

  12. File list: ALL.Adp.50.AllAg.Brown_adipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available ALL.Adp.50.AllAg.Brown_adipocytes mm9 All antigens Adipocyte Brown adipocytes SRX80...X800019,SRX185797,SRX478163,SRX478162 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/ALL.Adp.50.AllAg.Brown_adipocytes.bed ...

  13. File list: His.Adp.50.AllAg.Brown_preadipocytes [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adp.50.AllAg.Brown_preadipocytes mm9 Histone Adipocyte Brown preadipocytes SRX3...RX341421,SRX341046,SRX478160 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/His.Adp.50.AllAg.Brown_preadipocytes.bed ...

  14. File list: His.Adp.10.AllAg.Adipose_Tissue,_White [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adp.10.AllAg.Adipose_Tissue,_White hg19 Histone Adipocyte Adipose Tissue, White... http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Adp.10.AllAg.Adipose_Tissue,_White.bed ...

  15. File list: His.Adp.20.AllAg.Adipose_stromal_cell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available His.Adp.20.AllAg.Adipose_stromal_cell hg19 Histone Adipocyte Adipose stromal cell S...11,SRX019515,SRX019508 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/His.Adp.20.AllAg.Adipose_stromal_cell.bed ...

  16. File list: InP.Adp.20.Input_control.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available InP.Adp.20.Input_control.AllCell hg19 Input control Input control Adipocyte SRX0194...p://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/InP.Adp.20.Input_control.AllCell.bed ...

  17. Microtubule protein ADP-ribosylation in vitro leads to assembly inhibition and rapid depolymerization

    Energy Technology Data Exchange (ETDEWEB)

    Scaife, R.M. (Fred Hutchinson Cancer Research Center, Seattle, WA (United States)); Wilson, L. (Univ. of California, Santa Barbara (United States)); Purich, D.L. (Univ. of Florida, Gainesville (United States))

    1992-01-14

    Bovine brain microtubule protein, containing both tubulin and microtubule-associated proteins, undergoes ADP-ribosylation in the presence of ({sup 14}C)NAD{sup +} and a turkey erythrocyte mono-ADP-ribosyltransferase in vitro. The modification reaction could be demonstrated in crude brain tissue extracts where selective ADP-ribosylation of both the {alpha} and {beta} chains of tubulin and of the high molecular weight microtubule-associated protein MAP-2 occurred. In experiments with purified microtubule protein, tubulin dimer, the high molecular weight microtubule-associated protein MAP-2, and another high molecular weight microtubule-associated protein which may be a MAP-1 species were heavily labeled. Tubulin and MAP-2 incorporated ({sup 14}C)ADP-ribose to an average extent of approximately 2.4 and 30 mol of ADP-ribose/mol of protein, respectively. Assembly of microtubule protein into microtubules in vitro was inhibited by ADP-ribosylation, and incubation of assembled steady-state microtubules with ADP-ribosyltransferase and NAD{sup +} resulted in rapid depolymerization of the microtubules. Thus, the eukaryotic enzyme can ADP-ribosylate tubulin and microtubule-associated proteins to much greater extents than previously observed with cholera and pertussis toxins, and the modification can significantly modulate microtubule assembly and disassembly.

  18. Hydrostatic pressure and strain effects in short period InN/GaN superlattices

    DEFF Research Database (Denmark)

    Gorczyca, I.; Suski, T.; Christensen, Niels Egede

    2012-01-01

    The electronic structures of short-period pseudomorphically grown superlattices (SLs) of the form mInN/nGaN are calculated and the band gap variation with the well and the barrier thicknesses is discussed including hydrostatic pressure effects. The calculated band gap shows a strong dependence...... strongly on the strain conditions and SL geometry, but weakly on the applied external hydrostatic pressure....

  19. EFFECT OF ESSENTIAL OIL ON BIOFILM PRODUCTION BY DIFFERENT LISTERIA MONOCYTOGENES STRAINS

    OpenAIRE

    G. Comi; D Boscolo; C. Giusto; H Pustetto; L. Iacumin; M Manzano

    2008-01-01

    The effects of different essential oil (hexanal, 2-(E)-hexenal, carvacrol, citron, red orange, thymol and limonene) on biofilm production of some Lmonocytogenes strains are evaluated. The formation of biofilm on certain surfaces or on the food, seems to be related with cross-contamination during processing or with the contamination of the final product, with potential risk for the consumer. Many studies were done on the antimicrobial activity of essential oils and their components, but not to...

  20. Essential role of poly(ADP-ribosyl)ation in cocaine action

    Science.gov (United States)

    Scobie, Kimberly N.; Damez-Werno, Diane; Sun, HaoSheng; Shao, NingYi; Gancarz, Amy; Panganiban, Clarisse H.; Dias, Caroline; Koo, JaWook; Caiafa, Paola; Kaufman, Lewis; Neve, Rachael L.; Dietz, David M.; Shen, Li; Nestler, Eric J.

    2014-01-01

    Many of the long-term effects of cocaine on the brain’s reward circuitry have been shown to be mediated by alterations in gene expression. Several chromatin modifications, including histone acetylation and methylation, have been implicated in this regulation, but the effect of other histone modifications remains poorly understood. Poly(ADP-ribose) polymerase-1 (PARP-1), a ubiquitous and abundant nuclear protein, catalyzes the synthesis of a negatively charged polymer called poly(ADP-ribose) or PAR on histones and other substrate proteins and forms transcriptional regulatory complexes with several other chromatin proteins. Here, we identify an essential role for PARP-1 in cocaine-induced molecular, neural, and behavioral plasticity. Repeated cocaine administration, including self-administration, increased global levels of PARP-1 and its mark PAR in mouse nucleus accumbens (NAc), a key brain reward region. Using PARP-1 inhibitors and viral-mediated gene transfer, we established that PARP-1 induction in NAc mediates enhanced behavioral responses to cocaine, including increased self-administration of the drug. Using chromatin immunoprecipitation sequencing, we demonstrated a global, genome-wide enrichment of PARP-1 in NAc of cocaine-exposed mice and identified several PARP-1 target genes that could contribute to the lasting effects of cocaine. Specifically, we identified sidekick-1—important for synaptic connections during development—as a critical PARP-1 target gene involved in cocaine’s behavioral effects as well as in its ability to induce dendritic spines on NAc neurons. These findings establish the involvement of PARP-1 and PARylation in the long-term actions of cocaine. PMID:24449909

  1. Essential role of poly(ADP-ribosyl)ation in cocaine action.

    Science.gov (United States)

    Scobie, Kimberly N; Damez-Werno, Diane; Sun, HaoSheng; Shao, NingYi; Gancarz, Amy; Panganiban, Clarisse H; Dias, Caroline; Koo, JaWook; Caiafa, Paola; Kaufman, Lewis; Neve, Rachael L; Dietz, David M; Shen, Li; Nestler, Eric J

    2014-02-04

    Many of the long-term effects of cocaine on the brain's reward circuitry have been shown to be mediated by alterations in gene expression. Several chromatin modifications, including histone acetylation and methylation, have been implicated in this regulation, but the effect of other histone modifications remains poorly understood. Poly(ADP-ribose) polymerase-1 (PARP-1), a ubiquitous and abundant nuclear protein, catalyzes the synthesis of a negatively charged polymer called poly(ADP-ribose) or PAR on histones and other substrate proteins and forms transcriptional regulatory complexes with several other chromatin proteins. Here, we identify an essential role for PARP-1 in cocaine-induced molecular, neural, and behavioral plasticity. Repeated cocaine administration, including self-administration, increased global levels of PARP-1 and its mark PAR in mouse nucleus accumbens (NAc), a key brain reward region. Using PARP-1 inhibitors and viral-mediated gene transfer, we established that PARP-1 induction in NAc mediates enhanced behavioral responses to cocaine, including increased self-administration of the drug. Using chromatin immunoprecipitation sequencing, we demonstrated a global, genome-wide enrichment of PARP-1 in NAc of cocaine-exposed mice and identified several PARP-1 target genes that could contribute to the lasting effects of cocaine. Specifically, we identified sidekick-1--important for synaptic connections during development--as a critical PARP-1 target gene involved in cocaine's behavioral effects as well as in its ability to induce dendritic spines on NAc neurons. These findings establish the involvement of PARP-1 and PARylation in the long-term actions of cocaine.

  2. The NarE protein of Neisseria gonorrhoeae catalyzes ADP-ribosylation of several ADP-ribose acceptors despite an N-terminal deletion

    Science.gov (United States)

    Álamos-Musre, A. Said; Álvarez, Francisca P.; Escobar, Alejandro; Tapia, Cecilia V.; Osorio, Eduardo; Otero, Carolina; Calderón, Iván L.; Fuentes, Juan A.; Gil, Fernando; Paredes-Sabja, Daniel; Christodoulides, Myron

    2016-01-01

    The ADP-ribosylating enzymes are encoded in many pathogenic bacteria in order to affect essential functions of the host. In this study, we show that Neisseria gonorrhoeae possess a locus that corresponds to the ADP-ribosyltransferase NarE, a previously characterized enzyme in N. meningitidis. The 291 bp coding sequence of gonococcal narE shares 100% identity with part of the coding sequence of the meningococcal narE gene due to a frameshift previously described, thus leading to a 49-amino-acid deletion at the N-terminus of gonococcal NarE protein. However, we found a promoter region and a GTG start codon, which allowed expression of the protein as demonstrated by RT-PCR and western blot analyses. Using a gonococcal NarE–6xHis fusion protein, we demonstrated that the gonococcal enzyme underwent auto-ADP-ribosylation but to a lower extent than meningococcal NarE. We also observed that gonoccocal NarE exhibited ADP-ribosyltransferase activity using agmatine and cell-free host proteins as ADP-ribose acceptors, but its activity was inhibited by human β-defensins. Taken together, our results showed that NarE of Neisseria gonorrhoeae is a functional enzyme that possesses key features of bacterial ADP-ribosylating enzymes. PMID:27465490

  3. Mechanical behavior of composite based polypropylene: Recycling and strain rate effects

    Science.gov (United States)

    Bahlouli, N.; Pessey, D.; Ahzi, S.; Rémond, Y.

    2006-08-01

    Recycling effects on the dynamic response of composite based polypropylene is studied in this paper. Materials used here are filled and unfilled impact modified polypropylene. Nodules of EPDM represent the elastomeric phase for the filled composite based polypropylene. Fillers are particles of talc. For the unfilled polypropylene, the elastomeric phase is nodules of EPR. Different tensile tests, until rupture, were performed from quasi static to high strain rates. Virgin specimens were recycled in order to study the degradation due to the effect of recycling under dynamic loading. Thus microstructural effects due to dynamic loading and recycling were observed by SEM.

  4. Effects of nano bamboo charcoal on PAHs-degrading strain Sphingomonas sp. GY2B.

    Science.gov (United States)

    She, Bojia; Tao, Xueqin; Huang, Ting; Lu, Guining; Zhou, Zhili; Guo, Chuling; Dang, Zhi

    2016-03-01

    Nano bamboo charcoal (NBC) has been commonly used in the production of textiles, plastics, paint, etc. However, little is known regarding their effects towards the microorganisms. The effects of NBC on phenanthrene degrading strain Sphingomonas sp. GY2B were investigated in the present study. Results showed that the addition of NBC could improve the phenanthrene removal by Sphingomonas sp. GY2B, with removal efficiencies increased by 10.29-18.56% in comparison to the control at 24h, and phenanthrene was almost completely removed at 48h. With the presence of low dose of NBC (20 and 50mgL(-1)), strain GY2B displayed a better growth at 6h, suggesting that NBC was beneficial to the growth of GY2B and thus resulting in the quick removal of phenanthrene from water. However, the growth of strain GY2B in high dose of NBC (200mgL(-1)) was inhibited at 6h, and the inhibition could be attenuated and eliminated after 12h. NBC-effected phenanthrene solubility experiment suggested that NBC makes a negligible contribution to the solubilization of phenanthrene in water. Results of electronic microscopy analysis (SEM and TEM) indicated NBC may interact with the cell membrane, causing the enhanced membrane permeability and then NBC adsorbed on the membrane would enter into the cells. The findings of this work would provide important information for the future usage and long-term environmental risk assessment of NBC. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Fructooligosaccharides metabolism and effect on bacteriocin production in Lactobacillus strains isolated from ensiled corn and molasses.

    Science.gov (United States)

    Muñoz, M; Mosquera, A; Alméciga-Díaz, C J; Melendez, A P; Sánchez, O F

    2012-06-01

    Fructo- (FOS) and galacto-oligosaccharides have been used to promote the growth of probiotics, mainly those from Lactobacillus genus. However, only few reports have evaluated the effect of prebiotics on bacteriocins activity and production. In this work, we characterized the effect of FOS supplementation on the growth, lactic and acetic acids production, and antimicrobial activity of crude extracts obtained from Lactobacillus strains isolated from ensiled corn and molasses. Seven out of 28 isolated Lactobacillus, belonging to Lactobacillus casei, Lactobacillus plantarum, and Lactobacillus brevis, showed antimicrobial activity against Listeria innocua. Among them, the strain L. plantarum LE5 showed antimicrobial activity against Listeria monocytogenes and Enteroccocus faecalis; while the L. plantarum LE27 strain showed antimicrobial effect against L. monocytogenes, E. faecalis, Escherichia coli and Salmonella enteritidis. This antimicrobial activity in most of the cases was obtained only after FOS supplementation. In summary, these results show the feasibility to increase the antimicrobial activity of Lactobacillus bacteriocins by supplementing the growth medium with FOS. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. The effect of mechanical strains in soft tissues of the shoulder during load carriage.

    Science.gov (United States)

    Hadid, Amir; Belzer, Noa; Shabshin, Nogah; Zeilig, Gabi; Gefen, Amit; Epstein, Yoram

    2015-11-26

    Soldiers and recreational backpackers are often required to carry heavy loads during military operations or hiking. Shoulder strain appears to be one of the limiting factors of load carriage due to skin and underlying soft tissue deformations, trapped nerves, or obstruction of blood vessels. The present study was aimed to determine relationships between backpack weights and the state of loads in the shoulder׳s inner tissues, with a special focus on the deformations in the brachial plexus. Open-MRI scans were used for developing and then verifying a three-dimensional, non-linear, large deformation, finite element model of the shoulder. Loads were applied at the strap-shoulder contact surfaces of the model by pulling the strap towards the shoulder until the desired load was reached. Increasing the strap tensile forces up to a load that represents 35kg backpack resulted in gradual increase in strains within the underlying soft tissues: the maximal tensile strain in the brachial plexus for a 25kg backpack was 12%, and while carrying 35kg, the maximal tensile strain increased to 16%. The lateral aspect of the brachial plexus was found to be more vulnerable to deformation-inflicted effects than the medial aspect. This is due to the anatomy of the clavicle that poorly shields the plexus from compressive loads applied during load carriage, while the neural tissue in the medial aspect of the shoulder is better protected by the clavicle. The newly developed model can serve as a tool to estimate soft tissue deformations in the brachial plexus for heavy backpack loads, up to 35kg. This method will allow further development of new strap structures and materials for alleviating the strains applied on the shoulder soft tissues. Copyright © 2015 Elsevier Ltd. All rights reserved.

  7. Crystallographic and biochemical analysis of the mouse poly(ADP-ribose glycohydrolase.

    Directory of Open Access Journals (Sweden)

    Zhizhi Wang

    Full Text Available Protein poly(ADP-ribosylation (PARylation regulates a number of important cellular processes. Poly(ADP-ribose glycohydrolase (PARG is the primary enzyme responsible for hydrolyzing the poly(ADP-ribose (PAR polymer in vivo. Here we report crystal structures of the mouse PARG (mPARG catalytic domain, its complexes with ADP-ribose (ADPr and a PARG inhibitor ADP-HPD, as well as four PARG catalytic residues mutants. With these structures and biochemical analysis of 20 mPARG mutants, we provide a structural basis for understanding how the PAR polymer is recognized and hydrolyzed by mPARG. The structures and activity complementation experiment also suggest how the N-terminal flexible peptide preceding the PARG catalytic domain may regulate the enzymatic activity of PARG. This study contributes to our understanding of PARG catalytic and regulatory mechanisms as well as the rational design of PARG inhibitors.

  8. Effect of Pre-Strain on the Dielectric and Dynamic Mechanical Properties of HSIII Silicone

    National Research Council Canada - National Science Library

    Szabo, J. P; Underhill, R. S; Rawji, M; Keough, I. A

    2006-01-01

    ...% uni-axial pre strain. The mechanical loss factor was unaffected by pre strain. The real and imaginary parts of the complex dielectric permittivity were also unaffected by the application of a biaxial pre strain...

  9. Evaluation of the probiotic properties of new Lactobacillus and Bifidobacterium strains and their in vitro effect.

    Science.gov (United States)

    Presti, I; D'Orazio, G; Labra, M; La Ferla, B; Mezzasalma, V; Bizzaro, G; Giardina, S; Michelotti, A; Tursi, F; Vassallo, M; Di Gennaro, P

    2015-07-01

    Probiotic ingestion is recommended as a preventive approach to maintain the balance of the intestinal microbiota and to enhance the human well-being. During the whole life of each individual, the gut microbiota composition could be altered by lifestyle, diet, antibiotic therapies and other stress conditions, which may lead to acute and chronic disorders. Hence, probiotics can be administered for the prevention or treatment of some disorders, including lactose malabsorption, acute diarrhoea, irritable bowel syndrome, necrotizing enterocolitis and mild forms of inflammatory bowel disease. The probiotic-mediated effect is an important issue that needs to be addressed in relation to strain-specific probiotic properties. In this work, the probiotic properties of new Lactobacillus and Bifidobacterium strains were screened, and their effects in vitro were evaluated. They were screened for probiotic properties by determining their tolerance to low pH and to bile salts, antibiotic sensitivity, antimicrobial activity and vitamin B8, B9 and B12 production, and by considering their ability to increase the antioxidant potential and to modulate the inflammatory status of systemic-miming cell lines in vitro. Three out of the examined strains presenting the most performant probiotic properties, as Lactobacillus plantarum PBS067, Lactobacillus rhamnosus PBS070 and Bifidobacterium animalis subsp. lactis PBSO75, were evaluated for their effects also on human intestinal HT-29 cell line. The obtained results support the possibility to move to another level of study, that is, the oral administration of these probiotical strains to patients with acute and chronic gut disorders, by in vivo experiments.

  10. Simvastatin impairs ADP-stimulated respiration and increases mitochondrial oxidative stress in primary human skeletal myotubes.

    Science.gov (United States)

    Kwak, Hyo-Bum; Thalacker-Mercer, Anna; Anderson, Ethan J; Lin, Chien-Te; Kane, Daniel A; Lee, Nam-Sihk; Cortright, Ronald N; Bamman, Marcas M; Neufer, P Darrell

    2012-01-01

    Statins, the widely prescribed cholesterol-lowering drugs for the treatment of cardiovascular disease, cause adverse skeletal muscle side effects ranging from fatigue to fatal rhabdomyolysis. The purpose of this study was to determine the effects of simvastatin on mitochondrial respiration, oxidative stress, and cell death in differentiated primary human skeletal muscle cells (i.e., myotubes). Simvastatin induced a dose-dependent decrease in viability of proliferating and differentiating primary human muscle precursor cells, and a similar dose-dependent effect was noted in differentiated myoblasts and myotubes. Additionally, there were decreases in myotube number and size following 48 h of simvastatin treatment (5 μM). In permeabilized myotubes, maximal ADP-stimulated oxygen consumption, supported by palmitoylcarnitine+malate (PCM, complex I and II substrates) and glutamate+malate (GM, complex I substrates), was 32-37% lower (Prespiration at complex I. Mitochondrial superoxide and hydrogen peroxide generation were significantly greater in the simvastatin-treated human skeletal myotube cultures compared to control. In addition, simvastatin markedly increased protein levels of Bax (proapoptotic, +53%) and Bcl-2 (antiapoptotic, +100%, P<0.05), mitochondrial PTP opening (+44%, P<0.05), and TUNEL-positive nuclei in human skeletal myotubes, demonstrating up-regulation of mitochondrial-mediated myonuclear apoptotic mechanisms. These data demonstrate that simvastatin induces myotube atrophy and cell loss associated with impaired ADP-stimulated maximal mitochondrial respiratory capacity, mitochondrial oxidative stress, and apoptosis in primary human skeletal myotubes, suggesting that mitochondrial dysfunction may underlie human statin-induced myopathy. Copyright © 2011 Elsevier Inc. All rights reserved.

  11. Acetylcholine promotes Ca2+ and NO-oscillations in adipocytes implicating Ca2+→NO→cGMP→cADP-ribose→Ca2+ positive feedback loop--modulatory effects of norepinephrine and atrial natriuretic peptide.

    Directory of Open Access Journals (Sweden)

    Egor A Turovsky

    Full Text Available This study investigated possible mechanisms of autoregulation of Ca(2+ signalling pathways in adipocytes responsible for Ca(2+ and NO oscillations and switching phenomena promoted by acetylcholine (ACh, norepinephrine (NE and atrial natriuretic peptide (ANP.Fluorescent microscopy was used to detect changes in Ca(2+ and NO in cultures of rodent white adipocytes. Agonists and inhibitors were applied to characterize the involvement of various enzymes and Ca(2+-channels in Ca(2+ signalling pathways.ACh activating M3-muscarinic receptors and Gβγ protein dependent phosphatidylinositol 3 kinase induces Ca(2+ and NO oscillations in adipocytes. At low concentrations of ACh which are insufficient to induce oscillations, NE or α1, α2-adrenergic agonists act by amplifying the effect of ACh to promote Ca(2+ oscillations or switching phenomena. SNAP, 8-Br-cAMP, NAD and ANP may also produce similar set of dynamic regimes. These regimes arise from activation of the ryanodine receptor (RyR with the implication of a long positive feedback loop (PFL: Ca(2+→NO→cGMP→cADPR→Ca(2+, which determines periodic or steady operation of a short PFL based on Ca(2+-induced Ca(2+ release via RyR by generating cADPR, a coagonist of Ca(2+ at the RyR. Interplay between these two loops may be responsible for the observed effects. Several other PFLs, based on activation of endothelial nitric oxide synthase or of protein kinase B by Ca(2+-dependent kinases, may reinforce functioning of main PFL and enhance reliability. All observed regimes are independent of operation of the phospholipase C/Ca(2+-signalling axis, which may be switched off due to negative feedback arising from phosphorylation of the inositol-3-phosphate receptor by protein kinase G.This study presents a kinetic model of Ca(2+-signalling system operating in adipocytes and integrating signals from various agonists, which describes it as multivariable multi feedback network with a family of nested positive

  12. Effects of breeder age, strain, and eggshell temperature on nutrient metabolism of broiler embryos.

    Science.gov (United States)

    Nangsuay, A; Meijerhof, R; van den Anker, I; Heetkamp, M J W; Kemp, B; van den Brand, H

    2017-06-01

    Breeder age and broiler strain influence the availability of nutrients and oxygen through yolk size and eggshell conductance, and the effects of these egg characteristics on nutrient metabolism might be influenced by eggshell temperature (EST). This study aims to determine effects of breeder age, strain, and EST on nutrient metabolism of embryos. A study was designed as a 2 × 2 × 2 factorial arrangement using four batches of in total 4,464 hatching eggs of 2 flock ages at 29 to 30 wk (young) and 54 to 55 wk (old) of Ross 308 and Cobb 500. EST of 37.8 (normal) or 38.9°C (high) was applied from incubation day 7 (E7) until hatching. Wet yolk weight was determined mainly by breeder age (P = 0.043). Energy content in yolk (P = 0.004) and albumen + yolk (P = 0.005) were higher in old flock eggs than in young flock eggs, but did not differ between broiler strains. Eggshell conductance was higher in Ross 308 eggs than in Cobb 500 eggs (P availability of oxygen could have contributed to these differences. © 2016 Poultry Science Association Inc.

  13. High pressure homogenization versus heat treatment: effect on survival, growth, and metabolism of dairy Leuconostoc strains.

    Science.gov (United States)

    Guglielmotti, D M; Patrignani, F; Lanciotti, R; Guerzoni, M E; Reinheimer, J A; Quiberoni, A

    2012-09-01

    The effect of high pressure homogenization (HPH) with respect to a traditional heat treatment on the inactivation, growth at 8°C after treatments, and volatile profile of adventitious Leuconostoc strains isolated from Cremoso Argentino spoiled cheeses and ingredients used for their manufacture was evaluated. Most Leuconostoc strains revealed elevated resistance to HPH (eight passes, 100 MPa), especially when resuspended in skim milk. Heat treatment was more efficient than HPH in inactivating Leuconostoc cells at the three initial levels tested. The levels of alcohols and sulfur compounds increased during incubation at 8°C in HPH-treated samples, while the highest amounts of aldehydes and ketones characterized were in heated samples. Leuconostoc cells resuspended in skim milk and subjected to one single-pass HPH treatment using an industrial-scale machine showed remarkable reductions in viable cell counts only when 300 and 400 MPa were applied. However, the cell counts of treated samples rose rapidly after only 5 days of storage at 8°C. The Leuconostoc strains tested in this work were highly resistant to the inactivation treatments applied. Neither HPH nor heat treatment assured their total destruction, even though they were more sensitive to the thermal treatment. To enhance the inhibitory effect on Leuconostoc cells, HPH should be combined with a mild heat treatment, which in addition to efficient microbial inactivation, could allow maximal retention of the physicochemical properties of the product.

  14. Effects of strain rate and confining pressure on the deformation and failure of shale

    Energy Technology Data Exchange (ETDEWEB)

    Cook, J.M. (Schlumberger Cambridge Research (GB)); Sheppard, M.C. (Anadrill/Schlumberger (US)); Houwen, O.H. (Sedco Forex (FR))

    1991-06-01

    Previous work on shale mechanical properties has focused on the slow deformation rates appropriate to wellbore deformation. Deformation of shale under a drill bit occurs at a very high rate, and the failure properties of the rock under these conditions are crucial in determining bit performance and in extracting lithology and pore-pressure information from drilling parameters. Triaxial tests were performed on two nonswelling shales under a wide range of strain rates and confining and pore pressures. At low strain rates, when fluid is relatively free to move within the shale, shale deformation and failure are governed by effective stress or pressure (i.e., total confining pressure minus pore pressure), as is the case for ordinary rock. If the pore pressure in the shale is high, increasing the strain rate beyond about 0.1%/sec causes large increases in the strength and ductility of the shale. Total pressure begins to influence the strength. At high stain rates, the influence of effective pressure decreases, except when it is very low (i.e., when pore pressure is very high); ductility then rises rapidly. This behavior is opposite that expected in ordinary rocks. This paper briefly discusses the reasons for these phenomena and their impact on wellbore and drilling problems.

  15. Effect of LED Blue Light on Penicillium digitatum and Penicillium italicum Strains.

    Science.gov (United States)

    Lafuente, María T; Alférez, Fernando

    2015-11-01

    Studies on the antimicrobial properties of light have considerably increased due in part to the development of resistance to actual control methods. This study investigates the potential of light-emitting diodes (LED) blue light for controlling Penicillium digitatum and Penicillium italicum. These fungi are the most devastating postharvest pathogens of citrus fruit and cause important losses due to contaminations and the development of resistant strains against fungicides. The effect of different periods and quantum fluxes, delaying light application on the growth and morphology of P. digitatum strains resistant and sensitive to fungicides, and P. italicum cultured at 20°C was examined. Results showed that blue light controls the growth of all strains and that its efficacy increases with the quantum flux. Spore germination was always avoided by exposing the cultures to high quantum flux (700 μmol m(-2) s(-1) ) for 18 h. Continuous light had an important impact on the fungus morphology and a fungicidal effect when applied at a lower quantum flux (120 μmol m(-2) s(-1) ) to a growing fungus. Sensitivity to light increased with mycelium age. Results show that blue light may be a tool for P. digitatum and P. italicum infection prevention during handling of citrus fruits. © 2015 The American Society of Photobiology.

  16. Ra and the average effective strain of surface asperities deformed in metal-working processes

    DEFF Research Database (Denmark)

    Bay, Niels; Wanheim, Tarras; Petersen, A. S

    1975-01-01

    Based upon a slip-line analysis of the plastic deformation of surface asperities, a theory is developed determining the Ra-value (c.l.a.) and the average effective strain in the surface layer when deforming asperities in metal-working processes. The ratio between Ra and Ra0, the Ra-value after...... and before deformation, is a function of the nominal normal pressure and the initial slope γ0 of the surface asperities. The last parameter does not influence Ra significantly. The average effective strain View the MathML sourcege in the deformed surface layer is a function of the nominal normal pressure...... and γ0. View the MathML sourcege is highly dependent on γ0, View the MathML sourcege increasing with increasing γ0. It is shown that the Ra-value and the strain are hardly affected by the normal pressure until interacting deformation of the asperities begins, that is until the limit of Amonton's law...

  17. Effect of Antimicrobials on Salmonella Spp. Strains Isolated from Poultry Processing Plants

    Directory of Open Access Journals (Sweden)

    L Mion

    Full Text Available ABSTRACT The routine use of antimicrobials in animal production for the treatment of infections, disease prevention, or as growth promoters is a predisposing factor for the development and dissemination of antimicrobial resistance. In food industries, sanitizers are used for the control of microbial colonization, and their efficacy depends on contact time and on the dilution of the products used. The present study assessed the effect of 12 antimicrobials and four commercial sanitizers on 18 Salmonella spp. strains isolated from poultry processing plants. None of the evaluated antimicrobials was 100% effective against the tested Salmonella spp. strains; however, 94% of the isolates were susceptible to ciprofloxacin, 77% to amoxicillin + clavulanic acid and to ampicillin, and 72% to enrofloxacin, whereas 100% of the isolates were resistant to penicillin G, 16% to tetracycline, and 11% to sulfonamide. The tested Salmonella spp. strains were 100% inhibited by peracetic acid after five minutes of contact, 0.5% by quaternary ammonium after 15 minutes, and 85.7% by chlorhexidine after 15 minutes. The results indicate the importance of testing of efficacy of antimicrobials used in animal production and in public health to monitor their action and the development of resistance.

  18. Effect of tablets containing probiotic candidate strains on gingival inflammation and composition of the salivary microbiome

    DEFF Research Database (Denmark)

    Keller, M K; Brandsborg, E; Holmstrøm, K

    2018-01-01

    The aim of the study was to investigate clinical and microbial effects of probiotic candidate strains in patients with moderate gingivitis. The null hypothesis was that the clinical measurements with treatment would not differ from placebo. 47 adult patients were enrolled in a randomised placebo...... were analysed with Next Generation Sequencing (NGS) and qPCR. In contrast to the placebo group, there was a significant reduction in BOP and amount of GCF (Pprobiotic test group when compared with baseline. The general PI was less affected although there was a tendency...... of decreased plaque levels in the probiotic group (P=0.05-0.09). The cytokines were unaffected by the intervention as well as the salivary microbiome. The Shannon index showed no significant differences between the groups or alterations over time. The occurrence of both probiotic strains increased in saliva...

  19. Quality Factor Effect on the Wireless Range of Microstrip Patch Antenna Strain Sensors

    Directory of Open Access Journals (Sweden)

    Ali Daliri

    2014-01-01

    Full Text Available Recently introduced passive wireless strain sensors based on microstrip patch antennas have shown great potential for reliable health and usage monitoring in aerospace and civil industries. However, the wireless interrogation range of these sensors is limited to few centimeters, which restricts their practical application. This paper presents an investigation on the effect of circular microstrip patch antenna (CMPA design on the quality factor and the maximum practical wireless reading range of the sensor. The results reveal that by using appropriate substrate materials the interrogation distance of the CMPA sensor can be increased four-fold, from the previously reported 5 to 20 cm, thus improving considerably the viability of this type of wireless sensors for strain measurement and damage detection.

  20. Effects of Sex, Strain, and Energy Intake on Hallmarks of Aging in Mice

    DEFF Research Database (Denmark)

    Mitchell, Sarah J.; Madrigal-Matute, Julio; Scheibye-Knudsen, Morten

    2016-01-01

    Calorie restriction (CR) is the most robust non-genetic intervention to delay aging. However, there are a number of emerging experimental variables that alter CR responses. We investigated the role of sex, strain, and level of CR on health and survival in mice. CR did not always correlate...... with lifespan extension, although it consistently improved health across strains and sexes. Transcriptional and metabolomics changes driven by CR in liver indicated anaplerotic filling of the Krebs cycle together with fatty acid fueling of mitochondria. CR prevented ageassociated decline in the liver...... proteostasis network while increasing mitochondrial number, preserving mitochondrial ultrastructure and function with age. Abrogation of mitochondrial function negated life-prolonging effects of CR in yeast and worms. Our data illustrate the complexity of CR in the context of aging, with a clear separation...

  1. Strain effects in spinel ferrite thin films from first principles calculations

    Energy Technology Data Exchange (ETDEWEB)

    Fritsch, D; Ederer, Claude, E-mail: fritschd@tcd.ie [School of Physics, Trinity College Dublin, Dublin 2 (Ireland)

    2011-04-01

    The inverse spinel ferrimagnets CoFe{sub 2}O{sub 4} (CFO) and NiFe{sub 2}O{sub 4} (NFO) are of interest for applications in spin-filter devices or as building blocks of artificial multiferroic heterostructures. Here we present density functional theory calculations of the structural and magnetic properties of CFO and NFO, with special emphasis on strain-induced changes in the magneto-crystalline anisotropy energy. We find that tensile (compressive) strain favours perpendicular (in-plane) anisotropy, in agreement with experimental observations. Our calculated magnetostriction constants {lambda}{sub 100} agree well with available experimental data. Furthermore, the influence of different cation arrangements used to represent the inverse spinel structure and the effect of different exchange-correlation functionals are analysed and discussed.

  2. Effects of applied strain on nanoscale self-interstitial cluster formation in BCC iron

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Ning; Setyawan, Wahyu; Kurtz, Richard J.; Wang, Zhiguang

    2017-09-01

    The effect of applied strains on the configurational evolution of self-interstitial clusters in BCC iron (Fe) is explored with atomistic simulations. A novel cluster configuration is discovered at low temperatures (<600 K), which consists of <110> dumbbells and <111> crowdions in a specific configuration, resulting in an immobile defect. The stability and diffusion of this cluster at higher temperatures is explored. In addition, an anisotropy distribution factor of a particular [hkl] interstitial loop within the family of loops is calculated as a function of strain. The results show that loop anisotropy is governed by the angle between the stress direction and the orientation of the <111> crowdions in the loop, and directly linked to the stress induced preferred nucleation of self-interstitial atoms.

  3. Effects of applied strain on nanoscale self-interstitial cluster formation in BCC iron

    Science.gov (United States)

    Gao, Ning; Setyawan, Wahyu; Kurtz, Richard J.; Wang, Zhiguang

    2017-09-01

    The effect of applied strains on the configurational evolution of self-interstitial clusters in BCC iron (Fe) is explored with atomistic simulations. A novel cluster configuration is discovered at low temperatures (dumbbells and 〈 111 〉 crowdions in a specific configuration, resulting in an immobile defect. The stability and diffusion of this cluster at higher temperatures is explored. In addition, an anisotropy distribution factor of a particular [ hkl ] interstitial loop within the family of 〈 hkl 〉 loops is calculated as a function of strain. The results show that loop anisotropy is governed by the angle between the stress direction and the orientation of the 〈 111 〉 crowdions in the loop, and directly linked to the stress induced preferred nucleation of self-interstitial atoms.

  4. Cholera toxin can catalyze ADP-ribosylation of cytoskeletal proteins

    Energy Technology Data Exchange (ETDEWEB)

    Kaslow, H.R.; Groppi, V.E.; Abood, M.E.; Bourne, H.R.

    1981-11-01

    Cholera toxin catalyzes transfer of radiolabel from (/sup 32/P)NAD/sup +/ to several peptides in particulate preparations of human foreskin fibroblasts. Resolution of these peptides by two-dimensional gel electrophoresis allowed identification of two peptides of M/sub r/ = 42,000 and 52,000 as peptide subunits of a regulatory component of adenylate cyclase. The radiolabeling of another group of peptides (M/sub r/ = 50,000 to 65,000) suggested that cholera toxin could catalyze ADP-ribosylation of cytoskeletal proteins. This suggestion was confirmed by showing that incubation with cholera toxin and (/sup 32/P)NAD/sup +/ caused radiolabeling of purified microtubule and intermediate filament proteins.

  5. Hepatoprotective effects of kombucha tea: identification of functional strains and quantification of functional components.

    Science.gov (United States)

    Wang, Yong; Ji, Baoping; Wu, Wei; Wang, Ruojun; Yang, Zhiwei; Zhang, Di; Tian, Wenli

    2014-01-30

    Kombucha tea (KT), a traditional health beverage containing potential hepatoprotective agents, is fermented from sugared tea by a symbiotic culture of yeast and bacteria for 8 days. However, the functional strains that produce components for the hepatoprotective property of KT remain unclear. Multiple strains are involved in traditional KT production. Therefore, KT has not been standardized or produced commercially. This study aimed to identify the functional strains and quantify the functional components with hepatoprotective effects in kombucha tea. Gluconacetobacter sp. A4 was one of the microorganisms in KT in which the D-saccharic acid-1,4-lactone (DSL) produced by G. sp. A4 was significantly higher than that produced by original tea fungus at 8 days of fermentation. Traditional KT (TKT, tea broth fermented by mixed tea fungus), modified KT (MKT, fermented by single G. sp. A4), and DSL significantly inhibited the acetaminophen-induced increase of alanine aminotransferase, alkaline phosphatase, triglyceride and malondialdehyde, as well as facilitating the reduction of total antioxidant capacity in mice. Furthermore, MKT and TKT are both similar to DSL in terms of protection against acetaminophen-induced liver injury in mice. These results suggested a positive relationship between DSL content and the hepatoprotective effect of TKT, MKT and DSL groups. G. sp. A4 was concluded to be a potential functional strain and DSL might be the key functional component for the hepatoprotective property in KT. The stronger capability of G. sp. A4 in producing DSL makes it a better choice for the commercial production of KT. © 2013 Society of Chemical Industry.

  6. Estrogen's effects on activity, anxiety, and fear in two mouse strains.

    Science.gov (United States)

    Morgan, M A; Pfaff, D W

    2002-04-15

    Estrogen has effects on activity levels and emotional reactivity in both humans and rats. In a recent study conducted in ovariectomized (OVX) C57BL/6 (C57) mice we found that treatment with estradiol benzoate (EB) increased anxiety, fear learning, and running wheel activity relative to vehicle control (Veh). The present study was conducted to examine the stability of these findings across mouse strains (C57 and Swiss-Webster; SW), to get a better sense of the magnitude of the anxiety response by reducing baseline anxiety levels, and to discover if EB affects activity levels in a safe environment other than the home-cage running wheel. Mice of both strains treated with EB (s.c. implant, 25 microg in sesame oil, which enters the body over 5 weeks) were more anxious than Veh animals in the open field, elevated plus, and dark-light transition tests. SW animals were less anxious than C57 in the elevated plus. EB-treated animals of both strains were more active in the running wheel than Veh animals, and more active in the test of spontaneous activity in the home cage. EB-treatment also increased fear learning in a step-down avoidance task. EB appears to have a consistent but moderate effect in elevating anxiety and in increasing fear learning in two strains of mice. It is also involved in increasing activity in two different types of locomotion in the safer home cage. We conclude that these results of increased anxiety/fear and increased activity are suggestive of a general increase in arousal, with both sets of responses increasing the likelihood of reproductive behaviors occurring only when the environment predicts success.

  7. Effects of Saponins against Clinical E. coli Strains and Eukaryotic Cell Line

    Directory of Open Access Journals (Sweden)

    Michał Arabski

    2012-01-01

    Full Text Available Saponins are detergent-like substances showing antibacterial as well as anticancer potential. In this study, the effects of saponins from Quillaja saponaria were analyzed against prokaryotic and eukaryotic cells. Multidrug-resistant clinical E. coli strains were isolated from human urine. As eukaryotic cells, the CHO-K1 cell lines were applied. Antibacterial effect of ampicillin, streptomycin, and ciprofloxacin in the presence of saponins was measured by cultivation methods. Properties of saponins against CHO-K1 cells were measured by the MTT test, hemolysis assay and flow cytometry. Saponin from Quillaja saponaria has a cytotoxic effect at concentrations higher than 25 μg/mL and in the range of 12–50 μg/mL significantly increases the level of early apoptotic cells. Saponin at dose of 12 μg/mL enhances the six E. coli strains growth. We postulate that saponins increase the influx of nutrients from the medium into E. coli cells. Saponins do not have synergetic effects on antibacterial action of tested antibiotics. In contrary, in the presence of saponins and antibiotics, more CFU/mL E. coli cells were observed. This effect was similar to saponins action alone towards E. coli cells. In conclusion, saponins was cytotoxic against CHO-K1 cells, whereas against E. coli cells this effect was not observed.

  8. Effects of saponins against clinical E. coli strains and eukaryotic cell line.

    Science.gov (United States)

    Arabski, Michał; Węgierek-Ciuk, Aneta; Czerwonka, Grzegorz; Lankoff, Anna; Kaca, Wiesław

    2012-01-01

    Saponins are detergent-like substances showing antibacterial as well as anticancer potential. In this study, the effects of saponins from Quillaja saponaria were analyzed against prokaryotic and eukaryotic cells. Multidrug-resistant clinical E. coli strains were isolated from human urine. As eukaryotic cells, the CHO-K1 cell lines were applied. Antibacterial effect of ampicillin, streptomycin, and ciprofloxacin in the presence of saponins was measured by cultivation methods. Properties of saponins against CHO-K1 cells were measured by the MTT test, hemolysis assay and flow cytometry. Saponin from Quillaja saponaria has a cytotoxic effect at concentrations higher than 25 μg/mL and in the range of 12-50 μg/mL significantly increases the level of early apoptotic cells. Saponin at dose of 12 μg/mL enhances the six E. coli strains growth. We postulate that saponins increase the influx of nutrients from the medium into E. coli cells. Saponins do not have synergetic effects on antibacterial action of tested antibiotics. In contrary, in the presence of saponins and antibiotics, more CFU/mL E. coli cells were observed. This effect was similar to saponins action alone towards E. coli cells. In conclusion, saponins was cytotoxic against CHO-K1 cells, whereas against E. coli cells this effect was not observed.

  9. The effect of steam oxidation on the strain of fuel sheathing at high temperature

    International Nuclear Information System (INIS)

    Hunt, C.E.L.; Foote, D.E.; Grant, D.

    1976-08-01

    The current work extends previous data to include the effects of a steam atmosphere on the strain behaviour of fuel sheathing. At a heating rate of 25 deg C s -1 steam had little effect on the results at hoop stresses of 12 MPa because the time available for oxidation was too short. At 6 MPa hoop stress there was a marked difference between steam and vacuum results. The evidence suggests that, provided no cracks develop, the growing oxide and/or the oxygen stabilized α-phase zirconium layers rapidly take up the load as their combined thickness increases from 6 to about 30 μm. (author)

  10. Regulation of pyruvate oxidation in blowfly flight muscle mitochondria: requirement for ADP.

    Science.gov (United States)

    Bulos, B A; Thomas, B J; Shukla, S P; Sacktor, B

    1984-11-01

    Blowfly (Phormia regina) flight muscle mitochondria oxidized pyruvate ( + proline) in the presence of either ADP (coupled respiration) or carbonylcyanide-p-trifluoromethoxyphenylhydrazone (FCCP-uncoupled respiration). There was an absolute requirement for ADP (Km = 8.0 microM) when pyruvate oxidation was stimulated by FCCP in the presence of oligomycin. This requirement for ADP was limited to the oxidation of pyruvate; uncoupled alpha-glycerolphosphate oxidation proceeded maximally even in the absence of added ADP. Atractylate inhibited uncoupled pyruvate oxidation whether added before (greater than 99%) or after (95%) initiation of respiration with FCCP. In the presence of FCCP, oligomycin, and limiting concentrations of ADP (less than 110 microM), there was a shutoff in the uptake of oxygen. This inhibition of respiration was completely reversed by the addition of more ADP. Plots of net oxygen uptake as a function of the limiting ADP concentration were linear; the observed ADP/O ratio was 0.22 +/- 0.025. An ADP/O ratio of 0.2 was predicted if phosphorylation occurred only at the succinyl-CoA synthetase step of the tricarboxylate cycle. Experiments performed in the presence of limiting concentrations of ADP, and designed to monitor changes in the mitochondrial content of ADP and ATP, demonstrated that the shutoff in oxygen uptake was not due to the presence of a high intramitochondrial concentration of ATP. Indeed, ATP, added to the medium prior to the addition of FCCP, inhibited uncoupled pyruvate oxidation; the apparent KI was 0.8 mM. These results are consistent with the hypothesis that it is the intramitochondrial ATP/ADP ratio that is one of the controlling factors in determining the rate of flux through the tricarboxylate cycle. Changes in the mitochondrial content of citrate, isocitrate, alpha-ketoglutarate, and malate during uncoupled pyruvate oxidation in the presence of a limiting concentration of ADP were consistent with the hypothesis that the

  11. Parametric studies of metabolic cooperativity in Escherichia coli colonies: Strain and geometric confinement effects.

    Directory of Open Access Journals (Sweden)

    Joseph R Peterson

    relative fraction of acetate utilizing cells within the colonies varied by a factor of two. Additionally, growth with six different geometries designed to mimic those that might be found in a laboratory, a microfluidic device, and inside a living organism were considered. Geometries were found to have complex, often nonlinear effects on colony growth and cross-feeding with "hard" features resulting in larger effect than "soft" features. These results demonstrate that strain-specific features and spatial constraints imposed by the growth substrate can have significant effects even for microbial populations as simple as isogenic E. coli colonies.

  12. 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.

  13. Effect of plastic strain on shape memory characteristics in sputter-deposited Ti-Ni thin films

    International Nuclear Information System (INIS)

    Nomura, K.

    1995-01-01

    The plastic strain which is introduced during cooling and heating under a constant stress has an influence upon the transformation and deformation characteristics of sputter-deposited Ti-Ni shape memory alloy thin films. With increasing the accumulated plastic strain, Ms rises and recovery strain increases. The changes in such characteristics are due to the internal stress field that is formed by plastic deformation. However, the change in Ms in Ti-50.5at%Ni is larger than that in Ti-48.9at%Ni, although the plastic strain in the former is lower than that in the latter. In order to understand this point, the effective internal stresses were estimated in both alloys; the internal stress in the former is more effectively created by the introduction of plastic strain than in the latter. (orig.)

  14. Evaluation of the effects of strain rate on material properties of the high strength concrete used in nuclear facilities

    International Nuclear Information System (INIS)

    Kawaguchi, Shohei; Shirai, Koji; Takayanagi, Hideaki

    2011-01-01

    Concrete physical properties (compressive strength, tensile strength, initial elastic modulus and maximum strain) affected by strain rate weren't fully utilize for material model in dynamic response analysis for seismic and impact load because of few reports and various difficulties of impact tests. Split Hopkinson Pressure Bar (SHPB) methods are the most popular high-speed material testing and were also applied for composite material. We applied SHPB for concrete specimen and reported the strain rate effect to the concrete physical property. We used hydraulic testing device for 10 -5 /s to 10 0 /s strain rate and SHPB methods for over 10 1 /s. Four cases of concrete tests (high (50MPa at 28days)/low (35MPa at 28days) compressive strength (based on the test of exiting nuclear power facilities) and dry/wet condition) were done. And we formulated strain rate effect about compressive strength and initial elastic modulus from comparing with previous studies. (author)

  15. Strain and deformations engineered germanene bilayer double gate-field effect transistor by first principles

    Science.gov (United States)

    Meher Abhinav, E.; Chandrasekaran, Gopalakrishnan; Kasmir Raja, S. V.

    2017-10-01

    Germanene, silicene, stanene, phosphorene and graphene are some of single atomic materials with novel properties. In this paper, we explored bilayer germanene-based Double Gate-Field Effect Transistor (DG-FET) with various strains and deformations using Density Functional Theory (DFT) and Green's approach by first-principle calculations. The DG-FET of 1.6 nm width, 6 nm channel length (Lch) and HfO2 as gate dielectric has been modeled. For intrinsic deformation of germanene bilayer, we have enforced minute mechanical deformation of wrap and twist (5°) and ripple (0.5 Å) on germanene bilayer channel material. By using NEGF formalism, I-V Characteristics of various strains and deformation tailored DG-FET was calculated. Our results show that rough edge and single vacancy (5-9) in bilayer germanene diminishes the current around 47% and 58% respectively as compared with pristine bilayer germanene. In case of strain tailored bilayer DG-FET, multiple NDR regions were observed which can be utilized in building stable multiple logic states in digital circuits and high frequency oscillators using negative resistive techniques.

  16. [Effects of co-substrates on biodegradation of pyrene by ten bacterial strains].

    Science.gov (United States)

    Su, Dan; Li, Pei-Jun; Wang, Xin

    2007-03-01

    A total of 10 bacterial strains represented as from SB01 to SB10 were isolated from a petrolium-contaminated sludge, and their potential of degrading pyrene (PYR) was investigated on the substrates pyrene (MS1) , pyrene plus glucose (MS2), and pyrene plus phenanthrene (MS3). The results showed that on MS1, the degradation rate of PYR by SB01 was the highest, with 30.4% of PYR degraded after 5 days. On MS2, the degradation rate of PYR by SB09 was the highest, being 37.7% after 5 days, while on MS3, 50.2% of PYR was removed by SB01. The degradation of PYR by SB01 and SB03 was inhibited by glucose, which was more obvious for SB01, but no significant difference was observed among SB02, SB07, SB08 and SB10. The biodegradation rate of PYR by all the ten bacterial strains was enhanced on MS3, and that by SB10 was increased by 29.8%. For SB04 and SB09, the biodegradation rate of PYR had no significant difference between MS1 and MS2, but for other strains, the stimulation effect of phenanthrene on PYR degradation was higher than that of glucose.

  17. Effect of viscoelastic postseismic relaxation on estimates of interseismic crustal strain accumulation at Yucca Mountain, Nevada

    Science.gov (United States)

    Hammond, William C.; Kreemer, Corné; Blewitt, Geoffrey; Plag, Hans-Peter

    2010-03-01

    We estimate the long-term crustal strain rate at Yucca Mountain (YM), Nevada from GPS velocities taking into account viscoelastic relaxation following recent earthquakes to remove bias associated with transient deformation. The YM data reveal postseismic relaxation in time series non-linearity and geographic variation of the transient signal. From the data we estimate best-fitting lower crust and upper mantle viscosities of 1019.5 Pa s and 1018.5 Pa s, respectively. Once the relaxation model predictions are subtracted from the data, the long-term shear strain accumulation rate is between 16.3 and 25.1 nanostrains/year (ns/yr) to 99% confidence, a range much larger than the formal uncertainties from GPS measurement. We conclude that 1) a Maxwell viscoelastic model cannot explain all the deformation observed at YM, 2) uncertainty in viscosities dominates uncertainty in YM strain rates, and 3) the effects of large, recent earthquakes must be accounted for in seismic hazard studies using GPS.

  18. In vitro effects of various xenobiotics on Fusarium spp. strains isolated from cereals.

    Science.gov (United States)

    Wolny-Koładka, Katarzyna A

    2014-01-01

    This study aimed to determine the susceptibility of Fusarium spp. strains isolated from cereals to selected heavy metals, fungicides and silver nanoparticles. The experiments were conducted using 50 Fusarium strains belonging to five species: F. graminearum, F. culmorum, F. oxysporum, F. sporotrichioides and F. avenaceum. The strains were found to be highly resistant to Pb(2+) and Zn(2+). Medium resistance to Cu(2+) and Mn(2+) and low resistance to Cd(2+) and Fe(3+) was also observed. Among the tested fungicides, formulations containing azoxystrobin, prochloraz and tebuconazole proved to be the most effective in inhibiting the growth of fungi, as they affected fungal growth in each of the applied doses. Susceptibility of Fusarium spp. to nanosilver, demonstrated in this study, shows the legitimacy of using nanostructures as fungicidal agents. The results confirm high diversity of the analyzed fungal species in terms of susceptibility to the tested substances, and encourage to continue research on the resistance of Fusarium spp. to various fungicidal agents.

  19. Effect of Different Carbon Sources on Biosurfactants' Production by Three Strains of Lactobacillus spp.

    Science.gov (United States)

    Mouafo, Tene Hippolyte; Mbawala, Augustin; Ndjouenkeu, Robert

    2018-01-01

    The potential of three indigenous bacterial strains ( Lactobacillus delbrueckii N2, Lactobacillus cellobiosus TM1, and Lactobacillus plantarum G88) for the production of biosurfactants using sugar cane molasses or glycerol as substrates was investigated through emulsifying, surface tension, and antimicrobial activities. The different biosurfactants produced with molasses as substrate exhibited high surface tension reduction from 72 mN/m to values ranged from 47.50 ± 1.78 to 41.90 ± 0.79 mN/m and high emulsification index ranging from 49.89 ± 5.28 to 81.00 ± 1.14%. Whatever the Lactobacillus strain or the substrate used, the biosurfactants produced showed antimicrobial activities against Candida albicans LV1, some pathogenic and/or spoilage Gram-positive and Gram-negative bacteria. The yields of biosurfactants with molasses (2.43 ± 0.09 to 3.03 ± 0.09 g/L) or glycerol (2.32 ± 0.19 to 2.82 ± 0.05 g/L) were significantly ( p biosurfactants reveals that they are mainly glycoproteins and glycolipids with molasses and glycerol as substrate, respectively. Therefore, sugar cane molasses or glycerol can effectively be used by Lactobacillus strains as low-cost substrates to increase their biosurfactants production.

  20. Effect of Processing Route on Strain Controlled Low Cycle Fatigue Behavior of Polycrystalline NiAl

    Science.gov (United States)

    Rao, K. Bhanu Sankara; Lerch, B. A.; Noebe, R. D.

    1995-01-01

    The present investigation examines the effects of manufacturing process on the total axial strain controlled low cycle fatigue behavior of polycrystalline NiAl at 1000 K, a temperature above the monotonic Brittle-to-Ductile Transition Temperature (BDTT). The nickel aluminide samples were produced by three different processing routes: hot isostatic pressing of pre- alloyed powders, extrusion of prealloyed powders, and extrusion of vacuum induction melted ingots. The LCF behavior of the cast plus extruded material was also determined at room temperature (below the BD77) for comparison to the high temperature data. The cyclic stress response, cyclic stress-strain behavior, and strain-life relationships were influenced by the alloy preparation technique and the testing temperature. Detailed characterization of the LCF tested samples was conducted by optical and electron microscopy to determine the variations in fracture and deformation modes and to determine any microstructural changes that occurred during LCF testing. The dependence of LCF properties on processing route was rationalized on the basis of starting microstructure, brittle-to-ductile transition temperature, deformation induced changes in the basic microstructure, deformation substructure, and synergistic interaction between the damage modes.

  1. Physiological Effects of GLT1 Modulation in Saccharomyces cerevisiae Strains Growing on Different Nitrogen Sources.

    Science.gov (United States)

    Brambilla, Marco; Adamo, Giusy Manuela; Frascotti, Gianni; Porro, Danilo; Branduardi, Paola

    2016-02-01

    Saccharomyces cerevisiae is one of the most employed cell factories for the production of bioproducts. Although monomeric hexose sugars constitute the preferential carbon source, this yeast can grow on a wide variety of nitrogen sources that are catabolized through central nitrogen metabolism (CNM). To evaluate the effects of internal perturbations on nitrogen utilization, we characterized strains deleted or overexpressed in GLT1, encoding for one of the key enzymes of the CNM node, the glutamate synthase. These strains, together with the parental strain as control, have been cultivated in minimal medium formulated with ammonium sulfate, glutamate, or glutamine as nitrogen source. Growth kinetics, together with the determination of protein content, viability, and reactive oxygen species (ROS) accumulation at the single cell level, revealed that GLT1 modulations do not significantly influence the cellular physiology, whereas the nitrogen source does. As important exceptions, GLT1 deletion negatively affected the scavenging activity of glutamate against ROS accumulation, when cells were treated with H2O2, whereas Glt1p overproduction led to lower viability in glutamine medium. Overall, this confirms the robustness of the CNM node against internal perturbations, but, at the same time, highlights its plasticity in respect to the environment. Considering that side-stream protein-rich waste materials are emerging as substrates to be used in an integrated biorefinery, these results underline the importance of preliminarily evaluating the best nitrogen source not only for media formulation, but also for the overall economics of the process.

  2. Effect of gamma irradiation on the nutritional quality of Agaricus bisporus strains cultivated in different composts

    Energy Technology Data Exchange (ETDEWEB)

    Andrade, Meire Cristina Nogueira, E-mail: mcnandrade@hotmail.com [Universidade do Sagrado Coracao (USC), Bauru, SP (Brazil). Centro de Ciencias Exatas e Sociais Aplicadas; Jesus, Joao P.F.; Vieira, Fabricio R.; Viana, Sthefany R.F.; Minhoni, Marli T.A. [Universidade Estadual Paulista Julio de Mesquita Filho (FCA/UNESP), Botucatu, SP (Brazil). Fac. de Ciencias Agronomicas. Dept. de Producao Vegetal/Defesa Fitossanitaria, Modulo de Cogumelos; Spoto, Marta H.F. [Escola Superior de Agricultura Luiz de Queiroz (ESALQ/USP), Piracicaba, SP (Brazil). Departamento de Agroindustria, Alimentos e Nutricao

    2014-05-15

    The effect of irradiation doses (0, 125, 250 and 500 Gy) on the nutritional quality of A. bisporus mushrooms (strains ABI-07/06, ABI-05/03 and PB-1) cultivated in composts based on oat straw (Avena sativa) and brachiaria (Brachiaria sp.) was evaluated. The experimental design was 4 x 3 x 2 factorial scheme (irradiation doses x strains x composts), with 24 treatments, consisting of two repetitions each, totaling 48 experimental units (samples of mushrooms). The samples were irradiated in Cobalt-60 irradiator, model Gammacell 220 kGy, with dose rate of 0.740 kGy h{sup -1}, according to the treatments proposed. Subsequently, the control (unirradiated) and the other treatments were maintained at 4±1°C and 90% RH in a climatic chamber for carrying out the chemical analysis of the mushrooms on the 1st and 14th day of storage. It was found that all A. bisporus strains evaluated were food with excellent nutritional value, because they presented high protein and fiber contents and low ethereal extract content; the chemical characterization of the mushrooms was influenced by the compost type in which they were cultivated; gamma irradiation influenced the chemical composition of mushrooms. (author)

  3. Effects that different types of sports have on the hearts of children and adolescents and the value of two-dimensional strain-strain-rate echocardiography.

    Science.gov (United States)

    Binnetoğlu, Fatih Köksal; Babaoğlu, Kadir; Altun, Gürkan; Kayabey, Özlem

    2014-01-01

    Whether the hypertrophy found in the hearts of athletes is physiologic or a risk factor for the progression of pathologic hypertrophy remains controversial. The diastolic and systolic functions of athletes with left ventricular (LV) hypertrophy usually are normal when measured by conventional methods. More precise assessment of global and regional myocardial function may be possible using a newly developed two-dimensional (2D) strain echocardiographic method. This study evaluated the effects that different types of sports have on the hearts of children and adolescents and compared the results of 2D strain and strain-rate echocardiographic techniques with conventional methods. Athletes from clubs for five different sports (basketball, swimming, football, wrestling, and tennis) who had practiced regularly at least 3 h per week during at least the previous 2 years were included in the study. The control group consisted of sedentary children and adolescents with no known cardiac or systemic diseases (n = 25). The athletes were grouped according to the type of exercise: dynamic (football, tennis), static (wrestling), or static and dynamic (basketball, swimming). Shortening fraction and ejection fraction values were within normal limits for the athletes in all the sports disciplines. Across all 140 athletes, LV geometry was normal in 58 athletes (41.4 %), whereas 22 athletes (15.7 %) had concentric remodeling, 20 (14.3 %) had concentric hypertrophy, and 40 (28.6 %) had eccentric hypertrophy. Global LV longitudinal strain values obtained from the average of apical four-, two-, and three-chamber global strain values were significantly lower for the basketball players than for all the other groups (p < 0.001).

  4. Use of Mycobacterium smegmatis deficient in ADP-ribosyltransferase as surrogate for Mycobacterium tuberculosis in drug testing and mutation analysis.

    Science.gov (United States)

    Agrawal, Priyanka; Miryala, Sandeep; Varshney, Umesh

    2015-01-01

    Rifampicin (Rif) is a first line drug used for tuberculosis treatment. However, the emergence of drug resistant strains has necessitated synthesis and testing of newer analogs of Rif. Mycobacterium smegmatis is often used as a surrogate for M. tuberculosis. However, the presence of an ADP ribosyltransferase (Arr) in M. smegmatis inactivates Rif, rendering it impractical for screening of Rif analogs or other compounds when used in conjunction with them (Rif/Rif analogs). Rifampicin is also used in studying the role of various DNA repair enzymes by analyzing mutations in RpoB (a subunit of RNA polymerase) causing Rif resistance. These analyses use high concentrations of Rif when M. smegmatis is used as model. Here, we have generated M. smegmatis strains by deleting arr (Δarr). The M. smegmatis Δarr strains show minimum inhibitory concentration (MIC) for Rif which is similar to that for M. tuberculosis. The MICs for isoniazid, pyrazinamide, ethambutol, ciprofloxacin and streptomycin were essentially unaltered for M. smegmatis Δarr. The growth profiles and mutation spectrum of Δarr and, Δarr combined with ΔudgB (udgB encodes a DNA repair enzyme that excises uracil) strains were similar to their counterparts wild-type for arr. However, the mutation spectrum of ΔfpgΔarr strain differed somewhat from that of the Δfpg strain (fpg encodes a DNA repair enzyme that excises 8-oxo-G). Our studies suggest M. smegmatis Δarr strain as an ideal model system in drug testing and mutation spectrum determination in DNA repair studies.

  5. Use of Mycobacterium smegmatis deficient in ADP-ribosyltransferase as surrogate for Mycobacterium tuberculosis in drug testing and mutation analysis.

    Directory of Open Access Journals (Sweden)

    Priyanka Agrawal

    Full Text Available Rifampicin (Rif is a first line drug used for tuberculosis treatment. However, the emergence of drug resistant strains has necessitated synthesis and testing of newer analogs of Rif. Mycobacterium smegmatis is often used as a surrogate for M. tuberculosis. However, the presence of an ADP ribosyltransferase (Arr in M. smegmatis inactivates Rif, rendering it impractical for screening of Rif analogs or other compounds when used in conjunction with them (Rif/Rif analogs. Rifampicin is also used in studying the role of various DNA repair enzymes by analyzing mutations in RpoB (a subunit of RNA polymerase causing Rif resistance. These analyses use high concentrations of Rif when M. smegmatis is used as model. Here, we have generated M. smegmatis strains by deleting arr (Δarr. The M. smegmatis Δarr strains show minimum inhibitory concentration (MIC for Rif which is similar to that for M. tuberculosis. The MICs for isoniazid, pyrazinamide, ethambutol, ciprofloxacin and streptomycin were essentially unaltered for M. smegmatis Δarr. The growth profiles and mutation spectrum of Δarr and, Δarr combined with ΔudgB (udgB encodes a DNA repair enzyme that excises uracil strains were similar to their counterparts wild-type for arr. However, the mutation spectrum of ΔfpgΔarr strain differed somewhat from that of the Δfpg strain (fpg encodes a DNA repair enzyme that excises 8-oxo-G. Our studies suggest M. smegmatis Δarr strain as an ideal model system in drug testing and mutation spectrum determination in DNA repair studies.

  6. Tension–compression asymmetry in an extruded Mg alloy AM30: Temperature and strain rate effects

    Energy Technology Data Exchange (ETDEWEB)

    Zachariah, Z. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Tatiparti, Sankara Sarma V.; Mishra, S.K.; Ramakrishnan, N. [General Motors Technical Center, ITPL, Whitefield, Bangalore 560066 (India); Ramamurty, U., E-mail: ramu@materials.iisc.ernet.in [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India)

    2013-06-10

    The effect of strain rate, ε, and temperature, T, on the tension–compression asymmetry (TCA) in a dilute and wrought Mg alloy, AM30, over a temperature range that covers both twin accommodated deformation (below 250 °C in compression) as well as dislocation-mediated plasticity (above 250 °C) has been investigated. For this purpose, uniaxial tension and compression tests were conducted at T ranging from 25 to 400 °C with ε varying between 10{sup −2} and 10 s{sup −1}. In most of the cases, the stress–strain responses in tension and compression are distinctly different; with compression responses ‘concaving upward,’ due to {101-bar 2} tensile twinning at lower plastic strains followed by slip and strain hardening at higher levels of deformation, for T below 250 °C. This results in significant levels of TCA at T<250 °C, reducing substantially at high temperatures. At T=150 and 250 °C, high ε leads to high TCA, in particular at T=250 °C and ε=10 s{sup −1}, suggesting that twin-mediated plastic deformation takes precedence at high rates of loading even at sufficiently high T. TCA becomes negligible at T=350 °C; however at T=400 °C, as ε increases TCA gets higher. Microscopy of the deformed samples, carried out by using electron back-scattered diffraction (EBSD), suggests that at T>250 °C dynamic recrystallization begins between accompanied by reduction in the twinned fraction that contributes to the decrease of the TCA.

  7. The Effect of Body Weight on Heat Strain Indices in Hot and Dry Climatic Conditions

    Directory of Open Access Journals (Sweden)

    Habibi

    2016-03-01

    Full Text Available Background Being overweight is a characteristic that may influence a person’s heat exchange. Objectives The purpose of this study was to assess the effect of body weight on heat strain indices in hot and dry climatic conditions. Materials and Methods This study was completed with a sample of 30 participants with normal weights, as well as 25 participants who were overweight. The participants were physically inactive for a period of 120 minutes in a climatic chamber with hot and dry conditions (22 - 32°C and with 40% relative humidity (RH.The physiological strain index (PSI and heat strain score index (HSSI questionnaires were used. Simultaneous measurements were completed during heat exposure for periods of five minutes. The resting periods acted as the initial measurements for 15 minutes. Results In both groups, oral temperature, heart rate, and thermal perceptual responses increased during heat exposure. The means and standard deviations of heart rate and oral temperature were gathered when participants were in hot and dry climatic conditions and were not physically active. The heart rates and oral temperatures were 79.21 ± 5.93 bpm and 36.70 ± 0.45°C, respectively, for those with normal weights. For overweight individuals, the measurements for heart rate and oral temperature reached 82.21 ± 8.9 bpm and 37.84 ± 0.37°C, respectively. Conclusions The results showed that, compared to participants with normal weights, physiological and thermal perceptual responses were higher in overweight participants. Therefore, overweight individuals should avoid hot/dry weather conditions to decrease the amount of heat strain.

  8. Tunability of the Quantum Spin Hall Effect in Bi(110) Films: Effects of Electric Field and Strain Engineering.

    Science.gov (United States)

    Li, Sheng-Shi; Ji, Wei-Xiao; Li, Ping; Hu, Shu-Jun; Cai, Li; Zhang, Chang-Wen; Yan, Shi-Shen

    2017-06-28

    The quantum spin Hall (QSH) effect is promising for achieving dissipationless transport devices due to their robust gapless edge states inside insulating bulk gap. However, the currently discussed QSH insulators usually suffer from ultrahigh vacuum or low temperature due to the small bulk gap, which limits their practical applications. Searching for large-gap QSH insulators is highly desirable. Here, the tunable QSH state of a Bi(110) films with a black phosphorus (BP) structure, which is robust against structural deformation and electric field, is explored by first-principles calculations. It is found that the two-monolayer BP-Bi(110) film obtains a tunable large bulk gap by strain engineering and its QSH effect shows a favorable robustness within a wide range of combinations of in-plane and out-of-plane strains, although a single in-plane compression or out-of-plane extension may restrict the topological phase due to the self-doping effect. More interestingly, in view of biaxial strain, two competing physics on band topology induced by bonding-antibonding and p x,y -p z band inversions are obtained. Meanwhile, the QSH effect can be persevered under an electric field of up to 0.9 V/Å. Moreover, with appropriate in-plane strain engineering, a nontrivial topological phase in a four-monolayer BP-Bi(110) film is identified. Our findings suggest that these two-dimensional BP-Bi(110) films are ideal platforms of the QSH effect for low-power dissipation devices.

  9. [Effect of lung strain on pulmonary edema in dogs with acute respiratory distress syndrome].

    Science.gov (United States)

    Liu, Qi; Zheng, Hui; Li, Wen; Zeng, Qingsi; Cheng, Zhe; Chen, Rongchang

    2015-09-22

    To explore the effect of lung strain on pulmonary edema in dogs with acute respiratory distress syndrome (ARDS) preliminarily. Twenty dogs were recruited to induct ARDS models by venous injection of oleic acid and grouped into Group S1.0, S1.5, S2.0, S2.5 randomly, the lung strain was previously designated as 1.0, 1.5, 2.0 or 2.5 for each group. The ventilation was used to support the dogs for 24 hours with tidal volume calculated from lung strain, functional residual capacity and the volume recruitment by positive end expiratory pressure. Extra vascular lung water index (EVLWI) and pulmonary vascular permeability index (PVPI) were tested by thermodilution technique and wet to dry ratio of lung tissue was evaluated by weighing method. The tidal volume of Group S1.0, S1.5, S2.0, S2.5 was (7.5 ± 1.7), (13.9 ± 5.8), (17.9 ± 4.7) and (20.3 ± 7.9) ml/kg, respectively. After ventilation for 4 h, EVLWI in Group S2.0 and Group S2.5 were higher than them in Group S1.0 and Group S1.5 ((38.9 ± 6.5), (40.1 ± 7.7) vs (26.6 ± 5.2), (28.8 ± 5.4) ml/kg; F = 5.627, P = 0.009). At the end of study, PVPI of Group S2.5 increased significantly versus Group S1.0, S1.5 and S2.0 (16.7 ± 5.4 vs 7.0 ± 2.3, 9.2 ± 2.2, 11.5 ± 6.0; F = 4.329, P = 0.022). Wet to dry ratios of lung tissue in Group S2.0 and Group S2.5 were significantly higher than Group S1.0 and Group S1.5 (10.4 ± 1.2, 10.8 ± 1.5 vs 8.3 ± 1.2, 8.0 ± 2.2; F = 5.627, P = 0.009) after ventilation. Lung strain above 2.0 aggravates pulmonary edema dramatically and the effect might be slight if lung strain was smaller than 1.5.

  10. Modeling the intermixing effects in highly strained asymmetric InGaAs/GaAs quantum well

    Directory of Open Access Journals (Sweden)

    M. Souaf

    2015-09-01

    Full Text Available In this work, we have theoretically investigated the intermixing effect in highly strained In0.3Ga0.7As/GaAs QW taking into consideration the composition profile change resulting from in-situ indium surface segregation. To study the impact of the segregation effects on the postgrowth intermixing, one dimensional steady state Schrodinger equation and Fick's second law of diffusion have been numerically solved by using the finite difference methods. The impact of the In/Ga interdiffusion on the QW emission energy is considered for different In segregation coefficient. Our results show that the intermixed QW emission energy is strongly dependent on the segregation effects. The interdiffusion enhanced energy shift is found to be considerably reduced for higher segregation coefficients. This work adds considerable insight into the understanding and modeling of the effects of interdiffusion in semiconductor nanostructures.

  11. Fine-tuning of Smad protein function by poly(ADP-ribose polymerases and poly(ADP-ribose glycohydrolase during transforming growth factor β signaling.

    Directory of Open Access Journals (Sweden)

    Markus Dahl

    Full Text Available Initiation, amplitude, duration and termination of transforming growth factor β (TGFβ signaling via Smad proteins is regulated by post-translational modifications, including phosphorylation, ubiquitination and acetylation. We previously reported that ADP-ribosylation of Smads by poly(ADP-ribose polymerase 1 (PARP-1 negatively influences Smad-mediated transcription. PARP-1 is known to functionally interact with PARP-2 in the nucleus and the enzyme poly(ADP-ribose glycohydrolase (PARG can remove poly(ADP-ribose chains from target proteins. Here we aimed at analyzing possible cooperation between PARP-1, PARP-2 and PARG in regulation of TGFβ signaling.A robust cell model of TGFβ signaling, i.e. human HaCaT keratinocytes, was used. Endogenous Smad3 ADP-ribosylation and protein complexes between Smads and PARPs were studied using proximity ligation assays and co-immunoprecipitation assays, which were complemented by in vitro ADP-ribosylation assays using recombinant proteins. Real-time RT-PCR analysis of mRNA levels and promoter-reporter assays provided quantitative analysis of gene expression in response to TGFβ stimulation and after genetic perturbations of PARP-1/-2 and PARG based on RNA interference.TGFβ signaling rapidly induces nuclear ADP-ribosylation of Smad3 that coincides with a relative enhancement of nuclear complexes of Smads with PARP-1 and PARP-2. Inversely, PARG interacts with Smads and can de-ADP-ribosylate Smad3 in vitro. PARP-1 and PARP-2 also form complexes with each other, and Smads interact and activate auto-ADP-ribosylation of both PARP-1 and PARP-2. PARP-2, similar to PARP-1, negatively regulates specific TGFβ target genes (fibronectin, Smad7 and Smad transcriptional responses, and PARG positively regulates these genes. Accordingly, inhibition of TGFβ-mediated transcription caused by silencing endogenous PARG expression could be relieved after simultaneous depletion of PARP-1.Nuclear Smad function is negatively

  12. Fatigue History and in-situ Loading Studies of the overload Effect Using High Resolution X-ray Strain Profiling

    International Nuclear Information System (INIS)

    Croft, M.; Jisrawi, N.; Zhong, Z.; Holtz, R.; Sadananda, K.; Skaritka, J.; Tsakalakos, T.

    2007-01-01

    High-energy synchrotron X-ray diffraction experiments are used to perform local crack plane strain profiling of 4140 steel compact tension specimens fatigued at constant amplitude, subjected to a single overload cycle, then fatigued some more at constant amplitude. X-ray strain profiling results on a series of samples employing in-situ load cycling are correlated with the crack growth rate (da/dN) providing insight into the da/dN retardation known as the 'overload effect'. Immediately after the overload, the strain under maximum load is greatly reduced but the range of strain, between zero and maximum load, remains unchanged compared to the pre-overload values. At the point of maximum retardation, it is the strain range that is greatly reduced while the maximum-load strain has begun to recover to the pre-overload value. For a sample that has recovered to approximately half of the original da/dN value following the overload, the strain at maximum load is fully recovered while the strain range, though partially recovered, is still substantially reduced. The dominance of the strain range in the overload effect is clearly indicated. Subject to some assumptions, strong quantitative support for a crack growth rate driving force of the suggested form [(K max ) -p (ΔK) p ] γ is found. A dramatic nonlinear load dependence in the spatial distribution of the strain at maximum retardation is also demonstrated: at low load the response is dominantly at the overload position; whereas at high loads it is dominantly at the crack tip position. This transfer of load response away from the crack tip to the overload position appears fundamental to the overload effect for high R-ratio fatigue as studied here

  13. A theoretical investigation of the influence of the surface effect on the ferroelectric property of strained barium titanate film

    Science.gov (United States)

    Fang, Chao; Liu, Wei Hua

    2017-07-01

    The influence of the surface effect on the ferroelectric property of strained barium titanate film has been investigated. In this study, based on time-dependent Ginsburg-Landau-Devonshire thermodynamic theory, the surface effects have been simulated by introducing a surface constant, which leads to the strained BaTiO3 film consisting of inner tetragonal core and gradient lattice strain layer. Further, surface effects produce a depolarization field which has a dominant effect on the ferroelectric properties of the films. The spontaneous polarization, dielectric properties and ferroelectric hysteresis loop of BaTiO3 film are calculated under different boundary conditions. Theoretical and experimental results for strained BaTiO3 film are compared and discussed.

  14. Caloric restriction in lean and obese strains of laboratory rat: effects on body composition, metabolism, growth and overall health

    Data.gov (United States)

    U.S. Environmental Protection Agency — Data related to obese and lean strains of rat commonly used in the laboratory that are calorically restricted and its effects on physiologic parameters (Body...

  15. EFFECT OF ESSENTIAL OIL ON BIOFILM PRODUCTION BY DIFFERENT LISTERIA MONOCYTOGENES STRAINS

    Directory of Open Access Journals (Sweden)

    G. Comi

    2008-12-01

    Full Text Available The effects of different essential oil (hexanal, 2-(E-hexenal, carvacrol, citron, red orange, thymol and limonene on biofilm production of some Lmonocytogenes strains are evaluated. The formation of biofilm on certain surfaces or on the food, seems to be related with cross-contamination during processing or with the contamination of the final product, with potential risk for the consumer. Many studies were done on the antimicrobial activity of essential oils and their components, but not too much is known about their capacity to influence and reduce the microbial production of biofilm. Our data showed that essential oils can inhibit or limit the biofilm production.

  16. Effect of stress on variability of systemic hemodynamics in rats of various genetic strains.

    Science.gov (United States)

    Belkina, L M; Tarasova, O S; Kirillina, T N; Borovik, A S; Popkova, E V

    2003-09-01

    Power spectral density of heart rate fluctuations in the range of 0.02-5.00 Hz in August rats was lower than in Wistar rats. Changes in mean blood pressure and heart rate during stress (15-min immobilization) were similar in animals of both strains. As differentiated from Wistar rats, power spectral density of fluctuations in August rats considerably decreased after stress. August rats were characterized by low spectral power at rest and high resistance to the arrhythmogenic effect of 10-min acute myocardial ischemia.

  17. Effect of elastic interphase strains on extinction in aging nimonic type alloys

    International Nuclear Information System (INIS)

    Gitgarts, M.I.; Ivashin, V.V.

    1977-01-01

    The effect of νsup(')-phase separation processes on the variation of (3) CuKsub(α) diffraction line integral intensity in KhN67VMTYu alloy ageing has been investigated, the alloy being characterized by various degrees of volumetric inconsistency between the separation phase and matrix. The ageing of KhN67VMTYu alloy, in which the separation of the νsup(')-phase does not cause interphase strains, is not accompanied by abatement of extinction: the diffraction line intensity is practically the same for both aged and tempered specimens

  18. Poly(ADP-ribose) Glycohydrolase and Poly(ADP-ribose)-interacting Protein Hrp38 Regulate Pattern Formation during Drosophila Eye Development

    Science.gov (United States)

    Ji, Yingbiao; Jarnik, Michael; Tulin, Alexei V.

    2013-01-01

    Drosophila Hrp38, a homolog of human hnRNP A1, has been shown to regulate splicing, but its function can be modified by poly(ADP-ribosyl)ation. Notwithstanding such findings, our understanding of the roles of poly(ADP-ribosyl)ated Hrp38 on development is limited. Here, we have demonstrated that Hrp38 is essential for fly eye development based on a rough-eye phenotype with disorganized ommatidia observed in adult escapers of the hrp38 mutant. We also observed that Poly(ADP-ribose) Glycohydrolase (Parg) loss-of-function, which caused increased Hrp38 poly(ADP-ribosyl)ation, also resulted in the rough-eye phenotype with disrupted ommatidial lattice and reduced number of photoreceptor cells. In addition, ectopic expression of DE-cadherin, which is required for retinal morphogenesis, fully rescued the rough-eye phenotype of the hrp38 mutant. Similarly, Parg mutant eye clones had decreased expression level of DE-cadherin with orientation defects, which is reminiscent of DE-cadherin mutant eye phenotype. Therefore, our results suggest that Hrp38 poly(ADP-ribosyl)ation controls eye pattern formation via regulation of DE-cadherin expression, a finding which has implications for understanding the pathogenic mechanisms of Hrp38-related Fragile X syndrome and PARP1-related retinal degeneration diseases. PMID:23711619

  19. NMR resonance assignments of NarE, a putative ADP-ribosylating toxin from Neisseria meningitidis

    OpenAIRE

    Carlier, Ludovic; Koehler, Christian; Veggi, Daniele; Pizza, Mariagrazia; Soriani, Marco; Boelens, Rolf; Bonvin, Alexandre M. J. J.

    2010-01-01

    NarE is a 16 kDa protein identified from Neisseria meningitidis, one of the bacterial pathogens responsible for meningitis. NarE belongs to the ADP-ribosyltransferase family and catalyses the transfer of ADP-ribose moieties to arginine residues in target protein acceptors. Many pathogenic bacteria utilize ADP-ribosylating toxins to modify and alter essential functions of eukaryotic cells. NarE was proposed to bind iron through a Fe–S center which is supposed to be implied in catalysis. We hav...

  20. In vitro effects of selected contact lens care solutions on Acanthamoeba castellanii strains in Poland.

    Science.gov (United States)

    Padzik, Marcin; Chomicz, Lidia; Szaflik, Jacek P; Chruścikowska, Agnieszka; Perkowski, Konrad; Szaflik, Jerzy

    2014-11-01

    Free-living, cosmopolitan amoebae of the Acanthamoeba genus may be the causative agents of Acanthamoeba keratitis (AK) - a progressive, vision-threatening infection of the human cornea described particularly among contact lens wearers. Use of contact lens care solutions, effective against these organisms, is important in preventing AK infections. 3 different strains of Acanthamoeba castellanii of the T4 genotype (Neff strain and two others, isolated from patients with AK) were exposed to 4 selected multipurpose contact lens care solutions available in Poland: Ciba Vision AoSept Plus, Bausch & Lomb ReNu MultiPlus, Alcon Opti-Free, Ciba Vision Solo Care Aqua. No amoebicidal effect was observed. The strongest amoebostatic effect was visible after 24h of exposition to Opti-Free and ReNu solution and associated with percentage increase of rounded, motionless forms. This is significantly longer than minimum disinfection time recommended by manufacturers of all tested multipurpose solutions. Surprisingly, no clear induction of the encystation process was observed. Copyright © 2014 Elsevier Inc. All rights reserved.

  1. Modulation of persistent magnetoresistance by piezo-strain effect in manganite-based heterostructures

    Science.gov (United States)

    Li, W.; Yan, H.; Chai, X. J.; Wang, S. H.; Dong, X. L.; Ren, L. X.; Chen, C. L.; Jin, K. X.

    2017-05-01

    Persistent magnetoresistance effects in the phase-separated Pr0.65(Ca0.25Sr0.75)0.35MnO3/SrTiO3 and Pr0.65(Ca0.25Sr0.75)0.35MnO3/0.7PbMg1/3Nb2/3O3-0.3PbTiO3 heterostructures under a low magnetic field are investigated. It is observed that the persistent magnetoresistance effects decrease with increasing temperatures and the values for the heterostructures on 0.7Pb(Mg1/3Nb2/3)O3-0.3PbTiO3 and SrTiO3 substrates are about 86.6% and 33.2% at 40 K, respectively. More interestingly, the applied electric field on the 0.7PbMg1/3Nb2/3O3-0.3PbTiO3 substrate can suppress the persistent magnetoresistance effect, indicating that different energy landscapes can be dramatically modulated by the piezo-strain. These results are discussed in terms of the strain-induced competition in the ferromagnetic state and the charge-ordering phase by the energy scenario, which provide a promising approach for designing devices of electric-magnetic memories in all-oxide heterostructures.

  2. PWR clad ballooning: The effect of circumferential clad temperature variations on the burst strain/burst temperature relationship

    International Nuclear Information System (INIS)

    Barlow, P.

    1983-01-01

    By experiment, it has been shown by other workers that there is a reduction in the creep ductility of Zircaloy 4 in the α+β phase transition region. Results from single rod burst tests also show a reduction in burst strain in the α+β phase region. In this report it is shown theoretically that for single rod burst tests in the presence of circumferential temperature gradients, the temperature dependence of the mean burst strain is not determined by temperature variations in creep ductility, but is governed by the temperature sensitivity of the creep strain rate, which is shown to be a maximum in the α+β phase transition region. To demonstrate this effect, the mean clad strain at burst was calculated for creep straining at different temperature levels in the α, α+β and β phase regions. Cross-pin temperature gradients were applied which produced strain variations around the clad which were greatest in the α+β phase region. The mean strain at burst was determined using a maximum local burst strain (i.e. a creep ductility) which is independent of temperature. By assuming cross-pin temperature gradients which are typical of those observed during burst tests, then the calculated mean burst strain/burst temperature relationship gave good agreement with experiment. The calculations also show that when circumferential temperature differences are present, the calculated mean strain at burst is not sensitive to variations in the magnitude of the assumed creep ductility. This reduces the importance of the assumed burst criterion in the calculations. Hence a temperature independent creep ductility (e.g. 100% local strain) is adequate as a burst criterion for calculations under PWR LOCA conditions. (author)

  3. Metabolic consequences of DNA damage: The role of poly (ADP-ribose) polymerase as mediator of the suicide response

    International Nuclear Information System (INIS)

    Berger, N.A.; Berger, S.J.

    1986-01-01

    Recent studies show that DNA damage can produce rapid alterations in steady state levels of deoxynucleoside triphosphate pools, for example, MNNG or uv-irradiation cause rapid increases in dATP and dTTP pools without significant changes in dGTP or dCTP pools. In vitro, studies with purified eukaryotic DNA polymerases show that the frequency of nucleotide misincorporation was affected by alterations in relative concentrations of the deoxynucleoside triphosphates. Thus the alterations in dNTP pool sizes that occur consequent to DNA damage may contribute to an increased mutagenic frequency. Poly(ADP-ribose) polymerase mediated suicide mechanism may participate in the toxicity of adenosine deaminase deficiency and severe combined immune deficiency disease in humans. Individuals with this disease suffer severe lymphopenia due to the toxic effects of deoxyadenosine. The lymphocytotoxic effect of adenosine deaminase deficiency can be simulated in lymphocyte cell lines from normal individuals by incubating them with the adenosine deaminase inhibitor, deoxycoformycin. Incubation of such leukocytes with deoxycoformycin and deoxyadenosine results in the gradual accumulation of DNA strand breaks and the depletion of NAD + leading to cell death over a period of several days. This depletion of NAD and loss of cell viability were effectively blocked by nicotinamide or 3-amino benzamide. Thus, persistent activation of poly(ADP-ribose) polymerase by unrepaired or recurrent DNA strand breaks may activate the suicide mechanism of cell death. This study provides a basis for the interesting suggestion that treatment with nicotinamide could block the persistent activity of poly(ADP-ribose) polymerase and may help preserve lymphocyte function in patients with adenosine deaminase deficiency. 16 refs., 3 figs., 2 tabs

  4. Effect of a Sinorhizobium meliloti strain with a modified putA gene on the rhizosphere microbial community of alfalfa.

    Science.gov (United States)

    van Dillewijn, Pieter; Villadas, Pablo J; Toro, Nicolás

    2002-09-01

    The success of a rhizobial inoculant in the soil depends to a large extent on its capacity to compete against indigenous strains. M403, a Sinorhizobium meliloti strain with enhanced competitiveness for nodule occupancy, was recently constructed by introducing a plasmid containing an extra copy of a modified putA (proline dehydrogenase) gene. This strain and M401, a control strain carrying the same plasmid without the modified gene, were used as soil inoculants for alfalfa in a contained field release experiment at León, Spain. In this study, we determined the effects of these two strains on the indigenous microbial community. 16S rRNA genes were obtained from the rhizosphere of alfalfa inoculated with strain M403 or strain M401 or from noninoculated plants by amplification of DNA from soil with bacterial group-specific primers. These genes were analyzed and compared by restriction fragment length polymorphism and temperature gradient gel electrophoresis. The results allowed us to differentiate between alterations in the microbial community apparently caused by inoculation and by the rhizosphere effect and seasonal fluctuations induced by the alfalfa plants and by the environment. Only moderate inoculation-dependent effects could be detected, while the alfalfa plants appeared to have a much stronger influence on the microbial community.

  5. MD simulations to evaluate effects of applied tensile strain on irradiation-induced defect production at various PKA energies

    International Nuclear Information System (INIS)

    Miyashiro, S.; Fujita, S.; Okita, T.; Okuda, H.

    2012-01-01

    Highlights: ► Strain effects on defect formation were evaluated at various PKA energies by MD. ► Radiation-induced defects were increased numerically by external strain. ► Enhanced formation of larger clusters causes the numerical increase of defects. ► Strain influence on the number of defects was greatest at about 20 keV PKA. ► Cluster size, which is mostly affected by strain, was greater with higher PKA energy. - Abstract: Molecular Dynamics (MD) simulations were conducted to investigate the influence of applied tensile strain on defect production during cascade damages at various Primary Knock-on Atom (PKA) energies of 1–30 keV. When 1% strain was applied, the number of surviving defects increased at PKA energies higher than 5 keV, although they did not increase at 1 keV. The rate of increase by strain application was higher with higher PKA energy, and attained the maximum at 20 keV PKA energy with a subsequent gradual decrease at 30 keV PKA energy The cluster size, mostly affected by strain, was larger with higher PKA energy, although clusters with fewer than seven interstitials did not increase in number at any PKA energy.

  6. Strain rate effect on the mechanical behavior of the anterior cruciate ligament-bone complex

    OpenAIRE

    Pioletti, Dominique P.; Rakotomanana, L. R.; Leyvraz, P. F.

    1999-01-01

    Traction tests were performed on the bovine anterior cruciate ligament-bone complex at seven strain rates (0.1, 1, 5, 10, 20, 30, 40%/s). Corresponding stress-strain curves showed that, for a given strain level, the stress increased with the augmentation of the strain rate. This phenomenon was important since the stress increased by a factor of three between the tests performed at the lowest and highest strain rates. The influence of the strain rate was quantified with a new variable called t...

  7. Effect of indigenous Pseudomonas chlororaphis strains on morphological and main chemical growth parameters of basil (Ocimum basilicum L.

    Directory of Open Access Journals (Sweden)

    Stanojković-Sebić Aleksandra

    2017-01-01

    Full Text Available This study examined the effect of two indigenous plant growth promoting rhizobacterial strains of P. chlororaphis (Q16 and B25 on morphological (plant height; root length; number of leaves, buds and lateral branches and main chemical (contents of N, P, K, Ca, Mg growth parameters of two basil cultivars (Italiano classico and SRX 1920. The experiment was conducted in pots under glasshouse conditions from March to July 2014. Phosphorus was determined by spectrophotometer, potassium by flame emission photometry, nitrogen by using elemental CNS analyzer Vario EL III, while calcium and magnesium were determined by AAS. The obtained results showed that the treatment of basil cultivars with both P. chlororaphis strains had positive effect on all studied growth basil parameters in relation to the control, whereby the strain B25 was more effective than Q16. Concluding, tested P. chlororaphis strains have high potential in promoting the morphological and main chemical growth parameters of basil.

  8. Effect of Lactobacillus plantarum Strain K21 on High-Fat Diet-Fed Obese Mice

    Directory of Open Access Journals (Sweden)

    Chien-Chen Wu

    2015-01-01

    Full Text Available Recent studies have demonstrated beneficial effects of specific probiotics on alleviating obesity-related disorders. Here we aimed to identify probiotics with potential antiobesity activity among 88 lactic acid bacterial strains via in vitro screening assays, and a Lactobacillus plantarum strain K21 was found to harbor abilities required for hydrolyzing bile salt, reducing cholesterol, and inhibiting the accumulation of lipid in 3T3-L1 preadipocytes. Furthermore, effects of K21 on diet-induced obese (DIO mice were examined. Male C57Bl/6J mice received a normal diet, high-fat diet (HFD, or HFD with K21 administration (109 CFU in 0.2 mL PBS/day for eight weeks. Supplementation of K21, but not placebo, appeared to alleviate body weight gain and epididymal fat mass accumulation, reduce plasma leptin levels, decrease cholesterol and triglyceride levels, and mitigate liver damage in DIO mice. Moreover, the hepatic expression of peroxisome proliferator-activated receptor-γ (PPAR-γ related to adipogenesis was significantly downregulated in DIO mice by K21 intervention. We also found that K21 supplementation strengthens intestinal permeability and modulates the amount of Lactobacillus spp., Bifidobacterium spp., and Clostridium perfringens in the cecal contents of DIO mice. In conclusion, our results suggest that dietary intake of K21 protects against the onset of HFD-induced obesity through multiple mechanisms of action.

  9. The Saccharomyces boulardii CNCM I-745 strain shows protective effects against the B. anthracis LT toxin.

    Science.gov (United States)

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

    2015-10-30

    The probiotic yeast Saccharomyces boulardii (S. boulardii) has been prescribed for the prophylaxis and treatment of several infectious diarrheal diseases. Gastrointestinal anthrax causes fatal systemic disease. In the present study, we investigated the protective effects conferred by Saccharomyces boulardii CNCM I-745 strain on polarized T84 columnar epithelial cells intoxicated by the lethal toxin (LT) of Bacillus anthracis. Exposure of polarized T84 cells to LT affected cell monolayer integrity, modified the morphology of tight junctions and induced the formation of actin stress fibers. Overnight treatment of cells with S. boulardii before incubation with LT maintained the integrity of the monolayers, prevented morphological modification of tight junctions, restricted the effects of LT on actin remodeling and delayed LT-induced MEK-2 cleavage. Mechanistically, we demonstrated that in the presence of S. boulardii, the medium is depleted of both LF and PA sub-units of LT and the appearance of a cleaved form of PA. Our study highlights the potential of the S. boulardii CNCM I-745 strain as a prophylactic agent against the gastrointestinal form of anthrax.

  10. The Saccharomyces boulardii CNCM I-745 Strain Shows Protective Effects against the B. anthracis LT Toxin

    Directory of Open Access Journals (Sweden)

    Rodolphe Pontier-Bres

    2015-10-01

    Full Text Available The probiotic yeast Saccharomyces boulardii (S. boulardii has been prescribed for the prophylaxis and treatment of several infectious diarrheal diseases. Gastrointestinal anthrax causes fatal systemic disease. In the present study, we investigated the protective effects conferred by Saccharomyces boulardii CNCM I-745 strain on polarized T84 columnar epithelial cells intoxicated by the lethal toxin (LT of Bacillus anthracis. Exposure of polarized T84 cells to LT affected cell monolayer integrity, modified the morphology of tight junctions and induced the formation of actin stress fibers. Overnight treatment of cells with S. boulardii before incubation with LT maintained the integrity of the monolayers, prevented morphological modification of tight junctions, restricted the effects of LT on actin remodeling and delayed LT-induced MEK-2 cleavage. Mechanistically, we demonstrated that in the presence of S. boulardii, the medium is depleted of both LF and PA sub-units of LT and the appearance of a cleaved form of PA. Our study highlights the potential of the S. boulardii CNCM I-745 strain as a prophylactic agent against the gastrointestinal form of anthrax.

  11. Study of Antimicrobial Effects of Clarithromycin Loaded PLGA Nanoparticles against Clinical Strains of Helicobacter pylori.

    Science.gov (United States)

    Lotfipour, F; Valizadeh, H; Milani, M; Bahrami, N; Ghotaslou, R

    2016-01-01

    Clarithromycin (CLR) formulation was prepared as PLGA nanoparticles in order to enhance the therapeutic effects using the distinctive features of a nanoparticulate delivery system. CLR loaded PLGA nanoparticles were prepared by Quasi Emulsion Solvent Diffusion (QESD) method using Poly lactic-co-Glycolic Acid (PLGA) as a biodegradable polymer. Antibacterial activity of the prepared formulations was evaluated against clinical strains of Helicobacter pylori, isolated from gastric biopsies of patients with gastritis, duodenal ulcer, peptic ulcer, and gastroesophageal reflux disease undergoing endoscopy, by using agar dilution method.Spherical nanoparticles with relatively narrow size distribution (between 200 and 800 nm) in the size range of 305 ± 138, 344 ± 148 and 362 ± 110 nm were achieved for F22, F23 and F23 respectively. CLR encapsulation percentages were measured to be 57.4 ± 4.3 to 80.2 ± 4.0%. CLR loaded PLGA nanoparticles showed equal or enhanced eradication effect against H. pylori strains according to the declined MIC values in comparison with the untreated CLR.In conclusion, the prepared CLR nanoformulation showed appropriate physicochemical properties and improved activity against H. pylori that could be a suitable candidate for oral preparations. © Georg Thieme Verlag KG Stuttgart · New York.

  12. Size and strain rate effects in tensile strength of penta-twinned Ag nanowires

    Science.gov (United States)

    Zhang, Xuan; Li, Xiaoyan; Gao, Huajian

    2017-08-01

    Penta-twinned Ag nanowires (pt-AgNWs) have recently attracted much attention due to their interesting mechanical and physical properties. Here we perform large-scale atomistic simulations to investigate the influence of sample size and strain rate on the tensile strength of pt-AgNWs. The simulation results show an apparent size effect in that the nanowire strength (defined as the critical stress for dislocation nucleation) increases with decreasing wire diameter. To account for such size effect, a theoretical model involving the interaction between an emerging dislocation and the twin boundary has been developed for the surface nucleation of dislocations. It is shown that the model predictions are in quantitative agreement with the results from atomistic simulations and previous experimental studies in the literatures. The simulations also reveal that nanowire strength is strain-rate dependent, which predicts an activation volume for dislocation nucleation in the range of 1-10b3, where b is the magnitude of the Burgers vector for a full dislocation.

  13. The Effect of Intermittent Vest Cooling on Thermoregulation and Cardiovascular Strain in Baseball Catchers.

    Science.gov (United States)

    Bishop, Stacy H; Szymanski, David J; Ryan, Greg A; Herron, Robert L; Bishop, Phil A

    2017-08-01

    Bishop, SH, Szymanski, DJ, Ryan, GA, Herron, RL, and Bishop, PA. The effect of intermittent vest cooling on thermoregulation and cardiovascular strain in baseball catchers. J Strength Cond Res 31(8): 2060-2065, 2017-Baseball catchers are exposed to multiple physiological challenges while playing outside during the spring and summer months, many of which deal with recovery and thermoregulation. The purpose of this study was to investigate the effect of intermittent cooling on core temperature, cardiovascular strain, exertion, and recovery during a simulated catching performance in the heat. Six trained college-aged baseball catchers performed in a controlled, hot (35° C), and humid (25% relative humidity) environment in a counter-balanced, cross-over design. Ice vest cooling (VC) was used as a cooling modality and was compared with a control of no cooling (NC). Rectal temperature (Tre), heart rate (HR), rating of perceived exertion (RPE), and perceived recovery scale (PRS) were recorded before and after each simulated inning. All activities took place in a heat chamber, and each inning consisted of catchers receiving 12 pitches in their position followed by 6 minutes of recovery. Nine total innings were performed, and 27 total innings were performed with each of the 2 treatments. A significantly smaller mean Tre change was seen in VC when compared with NC (0.58 ± 0.2° C, 0.98 ± 0.2° C, p ≤ 0.01, respectively). Rating of perceived exertion was significantly lower and PRS was significantly improved for VC compared with NC (both p ≤ 0.05). Mean recovery HR during VC was significantly lower than NC in the fifth (VC = 84 ± 8 b·min, NC = 90 ± 9 b·min, p = 0.04), seventh (VC = 84 ± 3 b·min, NC = 92 ± 7 b·min, p = 0.02), and ninth (VC = 85 ± 7 b·min, NC = 93 ± 5 b·min, p = 0.01) innings. Heart rate during catching was significantly lower at the end of the VC trials when compared with NC (108 ± 16 b·min vs. 120 ± 19 b·min, p = 0.02, respectively

  14. Strain effects in the common-cation II-VI heterostructures: case of ZnS/ZnSe superlattices

    CERN Document Server

    Tit, N

    2003-01-01

    The electronic band-structures of the strained-layer ZnS/ZnSe (001) superlattices (SLs) have been investigated using the sp sup 3 s* tight-binding method, which includes the strain and spin-orbit effects. The SL band-structures are studied versus the biaxial strain, layer thickness, and band offsets. The results suggest that the common-cation II-VI heterojunction exhibit a vanishingly small conduction-band offset (CBO). It is shown that the SL valence-band top state is always a heavy-hole localized within ZnSe slabs; whereas the conduction-band edge state (electron) is sensitive to the biaxial strain (or VBO). To assess the strain effects, we considered three differently strained SLs corresponding to the three substrates: (i) ZnSe; (ii) ZnS sub 0 sub . sub 5 Se sub 0 sub . sub 5; and (iii) ZnS. The results show that all the studied SLs are of type-I except those strained to ZnS (case iii), that may exhibit type-I to type-II transition. One striking result obtained here is the existence of a critical VBO (V su...

  15. Effects of copper supplement on growth and viability of strains used as starters and adjunct cultures for Emmental cheese manufacture.

    Science.gov (United States)

    Rodríguez, L Mato; Alatossava, T

    2008-10-01

    To determine the effects of supplemented copper (Cu2+) on growth and viability of strains used as starters and adjunct cultures for Emmental cheese manufacture. Thirteen strains belonging to Lactobacillus delbrueckii, Lactobacillus helveticus, Lactobacillus rhamnosus, Streptococcus thermophilus or Propionibacterium freudenreichii species were exposed to various copper concentrations in the proper growth medium at relevant growth temperatures, and the effects of supplemented copper on bacterial growth and cell viability were determined by optical density and pH measurements, also by platings. Among the species considered, L. delbrueckii was the most copper resistant and S. thermophilus the most sensitive to copper. Anaerobic conditions increased this sensitivity significantly. There was also a considerable amount of variation in copper resistance at strain level. Copper resistance is both a species- and strain-dependent property and may reflect variability in copper-binding capacities by cell wall components among species and strains. In addition, the chemical state of copper may be involved. This study revealed that copper resistance is a highly variable property among starter and adjunct strains, and this variability should be considered when strains are selected for Emmental cheese manufacture.

  16. Effect of applied strain on phase separation of Fe-28 at.% Cr alloy: 3D phase-field simulation

    Science.gov (United States)

    Zhu, Lihui; Li, Yongsheng; Liu, Chengwei; Chen, Shi; Shi, Shujing; Jin, Shengshun

    2018-04-01

    A quantitative simulation of the separation of the α‧ phase in Fe-28 at.% Cr alloy under the effects of applied strain is performed by utilizing a three-dimensional phase-field model. The elongation of the Cr-enriched α‧ phase becomes obvious with the influence of applied uniaxial strain for the phase separation transforms from spinodal decomposition of 700 K to nucleation and growth of 773 K. The applied strain shows a significant influence on the early stage phase separation, and the influence is enlarged with the elevated temperature. The steady-state coarsening with the mechanism of spinodal decomposition is substantially affected by the applied strain for low-temperature aging, while the influence is reduced as the temperature increases and as the phase separation mechanism changes to nucleation and growth. The peak value of particle size distribution decreases, and the PSD for 773 K becomes more widely influenced by the applied strain. The simulation results of separation of the Cr-enriched α‧ phase with the applied strain provide a further understanding of the strain effect on the phase separation of Fe-Cr alloys from the metastable region to spinodal regions.

  17. Effect of activation on the porous structure and the strain and strength properties of beech wood biocarbon

    Science.gov (United States)

    Shpeizman, V. V.; Orlova, T. S.; Spitsyn, A. A.; Ponomarev, D. A.; Bogdanovich, N. I.; Martinez-Fernández, J.

    2017-01-01

    The effect of activation on the size, specific volume, and surface area of pores in a monolithic biomorphic material obtained by carbonization of beech wood is studied. It is shown that under optimal activation mode with a steam heated to 970°C, the total pore volume and surface, determined by adsorption curves, increased by 20 and 18 times, respectively. With the use of high-precision interferometric procedure, strain curves are obtained under uniaxial compression with a stepwise loading, and the strain rate is measured with a step of moving of 325 nm for activated and nonactivated samples. Despite an increase in porosity, the strength and maximum deformation of the samples do not decrease. The behavior of the strain rate jumps is analyzed in the micro- and nanometer range. It is shown that the maximum size of the micrometer jumps (4 μm) correlates well with the average size of the possible strain area in the samples (the average distance between the pores of small size), and the minimum dimensions of the strain jumps are close to the size of mesopores. Assessment of the strain change and its rate upon activation indicates that the effect of activation on the strain and strength characteristics is defined by nanometer defects, the most likely of which are microand mesopores.

  18. Preliminary crystallographic analysis of ADP-glucose pyrophosphorylase from Agrobacterium tumefaciens

    Energy Technology Data Exchange (ETDEWEB)

    Cupp-Vickery, Jill R., E-mail: jvickery@uci.edu; Igarashi, Robert Y.; Meyer, Christopher R.

    2005-03-01

    Crystallization and X-ray diffraction methods for native A. tumefaciens ADP-glucose pyrophosphorylase and its selenomethionyl derivative are described. Two crystal forms are identified, both of which diffract to 2 Å.

  19. Preliminary crystallographic analysis of ADP-glucose pyrophosphorylase from Agrobacterium tumefaciens

    International Nuclear Information System (INIS)

    Cupp-Vickery, Jill R.; Igarashi, Robert Y.; Meyer, Christopher R.

    2005-01-01

    Crystallization and X-ray diffraction methods for native A. tumefaciens ADP-glucose pyrophosphorylase and its selenomethionyl derivative are described. Two crystal forms are identified, both of which diffract to 2 Å

  20. Unscheduled synthesis of DNA and poly(ADP-ribose) in human fibroblasts following DNA damage

    International Nuclear Information System (INIS)

    McCurry, L.S.; Jacobson, M.K.

    1981-01-01

    Unscheduled DNA synthesis has been measured in human fibroblasts under conditions of reduced rates of conversion of NAD to poly)ADP-ribose). Cells heterozygous for the xeroderma pigmentosum genotype showed normal rates of uv induced unscheduled DNA synthesis under conditions in which the rate of poly(ADP-ribose) synthesis was one-half the rate of normal cells. The addition of theophylline, a potent inhibitor of poly(ADP-ribose) polymerase, to the culture medium of normal cells blocked over 90% of the conversion of NAD to poly(ADP-ribose) following treatment with uv or N-methyl-N'-nitro-N-nitro-soguanidine but did not affect the rate of unscheduled DNA synthesis