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Sample records for adult-plant htap resistance

  1. Genome-wide identification of QTLs conferring high-temperature adult-plant (HTAP) resistance to stripe rust (Puccinia striiformis f. sp. tritici) in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High-temperature adult-plant (HTAP) resistance to stripe rust (caused by Puccinia striiformis f. sp. tritici) is a durable type of resistance in wheat. The objective of this study was to identify quantitative trait loci (QTL) conferring HTAP resistance to stripe rust in a population consisting of 16...

  2. Expression of high-temperature adult-plant (HTAP) resistance against stripe rust (Puccinia striiformis f. sp. tritici) in wheat landraces

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stripe rust (Puccinia striiformis f. sp. tritici, Pst) is an important disease of wheat in the United States and Pakistan. Genetic resistance in wheat is a cost-effective and convenient control measure. In the present study, resistance testing of 115 wheat landraces from Pakistan was carried out ini...

  3. Genetic characterization and QTL mapping of high-temperature, adult-plant resistance in ‘Bancroft’ barley against Puccinia striiformis f. sp. hordei

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bancroft barley has been identified to have durable high-temperature adult-plant resistance (HTAP) to stripe rust (Puccinia striiformis f. sp. hordei). To map quantitative trait loci (QTL) for the HTAP resistance, Bancroft was crossed with susceptible Harrington barley. The parents and F4 and F5 pro...

  4. High-temperature adult-plant resistance, the key for sustainable control of stripe rust

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High-temperature adult-plant (HTAP) resistance expresses when plants grow old and the weather becomes warm. This non-race specific and durable type of resistance has been used successfully in control of wheat stripe rust in the U.S. since early 1960s. This article describes practical procedures f...

  5. Mapping a large number of QTL for durable resistance to stripe rust in winter wheat Druchamp using SSR and SNP markers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Winter wheat Druchamp has both high-temperature adult-plant (HTAP) resistance and all-stage resistance to stripe rust caused by Puccinia striiformis f. sp. tritici (Pst). The HTAP resistance in Druchamp is durable as the variety has been resistant in adult-plant stage since it was introduced ...

  6. Characterization and molecular mapping of Yr52 for high-temperature adult-plant resistance to stripe rust in spring wheat germplasm PI 183527.

    PubMed

    Ren, R S; Wang, M N; Chen, X M; Zhang, Z J

    2012-09-01

    Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most destructive diseases of wheat worldwide. Resistance is the best approach to control the disease. High-temperature adult-plant (HTAP) stripe rust resistance has proven to be race non-specific and durable. However, genes conferring high-levels of HTAP resistance are limited in number and new genes are urgently needed for breeding programs to develop cultivars with durable high-level resistance to stripe rust. Spring wheat germplasm PI 183527 showed a high-level of HTAP resistance against stripe rust in our germplasm evaluations over several years. To elucidate the genetic basis of resistance, we crossed PI 183527 and susceptible wheat line Avocet S. Adult plants of parents, F(1), F(2) and F(2:3) progeny were tested with selected races under the controlled greenhouse conditions and in fields under natural infection. PI 183527 has a single dominant gene conferring HTAP resistance. Resistance gene analog polymorphism (RGAP) and simple sequence repeat (SSR) markers in combination with bulked segregant analysis (BSA) were used to identify markers linked to the resistance gene. A linkage map consisting of 4 RGAP and 7 SSR markers was constructed for the resistance gene using data from 175 F(2) plants and their derived F(2:3) lines. Amplification of nulli-tetrasomic, ditelosomic and deletion lines of Chinese Spring with three RGAP markers mapped the gene to the distal region (0.86-1.0) of chromosome 7BL. The molecular map spanned a genetic distance of 27.3 cM, and the resistance gene was narrowed to a 2.3-cM interval flanked by markers Xbarc182 and Xwgp5258. The polymorphism rates of the flanking markers in 74 wheat lines were 74 and 30 %, respectively; and the two markers in combination could distinguish the alleles at the resistance locus in 82 % of tested genotypes. To determine the genetic relationship between this resistance gene and Yr39, a gene also on 7BL conferring HTAP resistance in

  7. Identification and mapping QTL for high-temperature adult-plant resistance to stripe rust in winter wheat (Triticum aestivum L.) cultivar 'Stephens'.

    PubMed

    Santra, D K; Chen, X M; Santra, M; Campbell, K G; Kidwell, K K

    2008-09-01

    High-temperature adult-plant (HTAP) resistance from the winter wheat (Triticum aestivum) cultivar 'Stephens' has protected wheat crops from stripe rust caused by Puccinia striiformis f. sp. tritici for 30 years. The objectives of this study were to identify quantitative trait loci (QTL) for HTAP resistance in Stephens through genetic linkage analysis and identify DNA markers linked to the QTL for use in marker-assisted breeding. Mapping populations consisted of 101 recombinant inbred lines (RILs) through single-seed descent from 'Stephens' (resistant) x 'Michigan Amber' (susceptible). F(5), F(6) and F(7) RILs were evaluated for stripe rust resistance at Pullman, WA in 1996, 1997 and 1998, respectively, whereas F(8) RILs were evaluated at Mt Vernon, WA, USA in 2005. The 101 F(8) RILs were evaluated with 250 resistance gene analog polymorphism (RGAP), 245 simple sequence repeat (SSR) and 1 sequence tagged site (STS) markers for genetic linkage map construction. Two QTL, which explained 48-61% of the total phenotypic variation of the HTAP resistance in Stephens, were identified. QYrst.wgp-6BS.1 was within a 3.9-cM region flanked by Xbarc101 and Xbarc136. QYrst.wgp-6BS.2 was mapped in a 17.5-cM region flanked by Xgwm132 and Xgdm113. Both two QTL were physically mapped to the short arm of chromosome 6B, but in different bins. Validation and polymorphism tests of the flanking markers in 43 wheat genotypes indicated that the molecular markers associated with these QTL should be useful in marker-assisted breeding programs to efficiently incorporate HTAP resistance into new wheat cultivars. PMID:18584147

  8. Identifying QTL for high-temperature adult-plant resistance to stripe rust (Puccinia striiformis f. sp. tritici) in the spring wheat (Triticum aestivum L.) cultivar 'Louise'.

    PubMed

    Carter, Arron Hyrum; Chen, X M; Garland-Campbell, K; Kidwell, K K

    2009-10-01

    Over time, many single, all-stage resistance genes to stripe rust (Puccinia striiformis f. sp. tritici) in wheat (Triticum aestivum L.) are circumvented by race changes in the pathogen. In contrast, high-temperature, adult-plant resistance (HTAP), which only is expressed during the adult-plant stage and when air temperatures are warm, provides durable protection against stripe rust. Our objective was to identify major quantitative trait loci (QTL) for HTAP resistance to stripe rust in the spring wheat cultivar 'Louise'. The mapping population consisted of 188 recombinant inbred lines (RIL) from a Louise (resistant) by 'Penawawa' (susceptible) cross. F(5:6) lines were evaluated for stripe rust reaction under natural infection in replicated field trials at five locations in the US Pacific Northwest in 2007 and 2008. Infection type (IT) and disease severity were recorded for each RIL 2-4 times per location. In all environments, Penawawa, the susceptible parent, was rated with an IT ranging from 6 to 8 at all growth stages evaluated. In contrast, Louise, the resistant parent, was rated with an IT of 2 or 3 across growth stages. Distribution of IT values was bimodal, indicating a single major gene was affecting the trait. The parents and RIL population were evaluated with 295 polymorphic simple sequence repeat and one single nucleotide polymorphism markers. One major QTL, designated QYrlo.wpg-2BS, associated with HTAP resistance in Louise, was detected on chromosome 2BS (LOD scores ranging from 5.5 to 62.3 across locations and years) within a 16.9 cM region flanked by Xwmc474 and Xgwm148. SSR markers associated with QYrlo.wpg-2BS are currently being used in marker-based forward breeding strategies to transfer the target region into adapted germplasm to improve the durability of resistance in resulting cultivars. PMID:19644666

  9. Quantitative trait loci for non-race-specific, high-temperature adult-plant resistance to stripe rust in wheat cultivar Express.

    PubMed

    Lin, F; Chen, X M

    2009-02-01

    Wheat cultivar Express has durable, high-temperature adult-plant (HTAP) resistance to stripe rust (Puccinia striiformis f. sp. tritici). To elucidate the genetic basis of the resistance, Express was crossed with 'Avocet Susceptible' (AVS). A mapping population of 146 F(5) recombinant inbred lines (RILs) was developed using single-seed descent. The RILs were evaluated at two sites near Pullman in eastern Washington and one site near Mount Vernon in western Washington in 2005, and were evaluated near Pullman in 2006 under natural stripe rust infection of predominant races virulent on seedlings of Express. Infection type (IT) and disease severity (DS) were recorded three times for each line during each growing season. The DS data were used to calculate relative area under the disease progress curve (rAUDPC) values. Both IT and rAUDPC data showed continuous distributions, indicating that the Express HTAP resistance was controlled by quantitative trait loci (QTL). Resistance gene analog polymorphism (RGAP) and simple sequence repeat (SSR) techniques were used to map the HTAP resistance QTL. Three QTL were detected with significant additive effects, explaining 49.5-69.6% of the phenotypic variation for rAUDPC. Two of the QTL explained 30.8-42.7% of the phenotypic variation for IT. The three QTL were mapped to wheat chromosomes 6AS, 3BL and 1BL, and were designated as QYrex.wgp-6AS, QYrex.wgp-3BL and QYrex.wgp-1BL, respectively. QYrex.wgp-6AS and QYrex.wgp-3BL, which had higher effects than QYrex.wgp-1BL, were different from previously reported QTL/genes for adult-plant resistance. Markers Xgwm334-Xwgp56 and Xgwm299-Xwgp66 flanking the two major QTL were highly polymorphic in various wheat genotypes, suggesting that these markers are useful in marker-assisted selection. PMID:18815766

  10. Genetics and molecular mapping of genes for race-specific all-stage resistance and non-race-specific high-temperature adult-plant resistance to stripe rust in spring wheat cultivar Alpowa.

    PubMed

    Lin, F; Chen, X M

    2007-05-01

    Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most widespread and destructive wheat diseases worldwide. Growing resistant cultivars is the preferred control of the disease. The spring wheat cultivar 'Alpowa' has both race-specific, all-stage resistance and non-race-specific, high-temperature adult-plant (HTAP) resistances to stripe rust. To identify genes for the stripe rust resistances, Alpowa was crossed with 'Avocet Susceptible' (AVS). Seedlings of the parents, and F(1), F(2) and F(3) progeny were tested with races PST-1 and PST-21 of P. striiformis f. sp. tritici under controlled greenhouse conditions. Alpowa has a single partially dominant gene, designated as YrAlp, conferring all-stage resistance. Resistance gene analog polymorphism (RGAP) and simple sequence repeat (SSR) techniques were used to identify molecular markers linked to YrAlp. A linkage group of five RGAP markers and two SSR markers was constructed for YrAlp using 136 F(3) lines. Amplification of a set of nulli-tetrasomic Chinese Spring lines with RGAP markers Xwgp47 and Xwgp48 and the two SSR markers indicated that YrAlp is located on the short arm of chromosome 1B. To map quantitative trait loci (QTLs) for the non-race-specific HTAP resistance, the parents and 136 F(3) lines were tested at two sites near Pullman and one site near Mount Vernon, Washington, under naturally infected conditions. A major HTAP QTL was consistently detected across environments and was located on chromosome 7BL. Because of its chromosomal location and the non-race-specific nature of the HTAP resistance, this gene is different from previously described genes for adult-plant resistance, and is therefore designated Yr39. The gene contributed to 64.2% of the total variation of relative area under disease progress curve (AUDPC) data and 59.1% of the total variation of infection type data recorded at the heading-flowering stages. Two RGAP markers, Xwgp36 and Xwgp45 with the highest R (2) values

  11. Gene action for adult-plant resistance to powdery mildew in wheat.

    PubMed

    Das, M K; Griffey, C A

    1995-04-01

    Gene action for adult-plant resistance to powdery mildew was studied using generation mean analyses of parents and of F1, F2, and backcross populations derived from a diallel cross of one susceptible and three adult-plant resistant wheat cultivars. Joint scaling tests showed that an additive-dominance model was sufficient to explain the variability in the expression of adult-plant resistance in one cross, while digenic epistasis was involved in the other five crosses. Additive gene effects were predominant; however, dominance was significant in four crosses, additive x additive interaction was significant in three crosses, additive x dominance interaction was significant in three crosses, and dominance x dominance interaction was significant in one cross. Therefore, selection for adult-plant resistance would likely be most effective in advanced generations derived from crosses among the adult-plant resistant cultivars Redcoat, Houser, and Massey. PMID:18470166

  12. Lesion Mimic Associates with Adult Plant Resistance to Leaf Rust Infection in Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Lesion mimics (LM) that resemble plant disease symptoms in the absence of plant pathogens may confer enhanced plant disease resistance to a wide range of pathogens. Wheat line Ning7840 has adult plant resistance (APR) to leaf rust (Puccinia triticina) and shows LM symptoms at heading. A recessive ge...

  13. Genomic selection for quantitative adult plant stem rust resistance in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Quantitative adult plant resistance (APR) to stem rust (Puccinia graminis f. sp. tritici) is an important breeding target in wheat (Triticum aestivum L.) and a potential target for genomic selection (GS). To evaluate the relative importance of known APR loci in applying genomic selection, we charact...

  14. Identification of QTL for adult plant resistance to stripe rust in Chinese wheat landrace Caoxuan 5

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Yellow (or stripe) rust, caused by Puccinia striiformis f. sp. tritici (Pst), is an important wheat disease worldwide. The development of wheat cultivars with adult plant resistance (APR) has been given increasing emphasis in recent years because of the reputed durability of APR compared to all-stag...

  15. Toward understanding molecular mechanisms of durable and non-durable resistance to stripe rust in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stripe rust of wheat, caused by Puccinia striiformis f. sp. tritici, continues causing severe damage worldwide. Durable resistance is a key for sustainable control of the disease. High-temperature adult-plant (HTAP) resistance, which expresses when weather becomes warm and plants grow old, has bee...

  16. Adult Plant Phenotype of the Rp1-DJ Compound Rust Resistance Gene in Maize.

    PubMed

    Hu, G; Webb, C A; Hulbert, S H

    1997-03-01

    ABSTRACT The complex structure of the rp1 rust resistance locus of maize allows two or more resistance genes to be recombined together in coupling phase. The phenotypic effects of the Rp1-DJ compound gene, which carries both Rp1-D and Rp1-J, were analyzed. The Rp1-DJ compound gene was associated with a chlorotic spotting phenotype in some genetic backgrounds. At the seedling stage, lines carrying Rp1-DJ are fully susceptible to Puccinia sorghi biotype HI1, which is virulent on lines with the two genes singly. At later stages of growth, however, Rp1-DJ lines show partial resistance when compared with sibling lines not carrying the compound gene. The Rp1-DJ gene also confers partial resistance to P. polysora in adult plants. PMID:18945165

  17. Molecular Mapping of Adult-Plant Race-Specific Leaf Rust Resistance Gene Lr12 in Bread Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wheat (Triticum aestivum) gene Lr12 provides adult-plant race-specific resistance to leaf rust caused by Puccinia triticina. It is completely linked or identical to Lr31, which confers seedling resistance only when the complementary gene Lr27 is also present. F2 and F2-derived F3 families were devel...

  18. Identification and mapping of adult plant stripe rust resistance in soft red winter wheat VA00W-38

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Virginia Tech experimental wheat (Triticum aestivum L.) line VA00W-38 has adult plant resistance to race PST-100, which was the predominant race of stripe rust (Puccinia striiformis f. sp. tritici) in the United States from 2003 to 2006. Resistance was characterized in a cross between VA00W-38 a...

  19. Identification and mapping of adult plant stripe rust resistance in soft red winter wheat cultivar ‘USG 3555’

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about the extent or diversity of resistance in soft red winter wheat (Triticum aestivum L.) to stripe rust, caused by the fungal pathogen Puccinia striiformis f.sp. tritici. The soft red winter (SRW) wheat cultivar ‘USG 3555’ has effective adult-plant resistance to stripe rust, which...

  20. Identification and mapping of adult-plant stripe rust resistance in soft red winter wheat cultivar ‘USG 3555'

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about the extent or diversity of resistance in soft red winter wheat (Triticum aestivum L.) to stripe rust, caused by the fungal pathogen Puccinia striiformis f.sp. tritici. The soft red winter (SRW) wheat cultivar ‘USG 3555’ has effective adult-plant resistance to stripe rust, which...

  1. Confirmation of Three Quantitative Trait Loci Conferring Adult Plant Resistance to Powdery Mildew in Two Winter Wheat Populations

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Hypersensitive, race specific genes primarily have been deployed to control powdery mildew (caused by Blumeria graminis) in wheat (Triticum aestivum); however, recent efforts have shifted to breeding for more durable resistance. Previously, three QTL for adult plant resistance (APR) to powdery milde...

  2. Genome-Wide Association Mapping for Seedling and Adult Plant Resistance to Stripe Rust in Synthetic Hexaploid Wheat

    PubMed Central

    Makdis, Farid; Badebo, Ayele; Ogbonnaya, Francis C.

    2014-01-01

    Use of genetic diversity from related wild and domesticated species has made a significant contribution to improving wheat productivity. Synthetic hexaploid wheats (SHWs) exhibit natural genetic variation for resistance and/or tolerance to biotic and abiotic stresses. Stripe rust caused by (Puccinia striiformis f. sp. tritici; Pst), is an important disease of wheat worldwide. To characterise loci conferring resistance to stripe rust in SHWs, we conducted a genome-wide association study (GWAS) with a panel of 181 SHWs using the wheat 9K SNP iSelect array. The SHWs were evaluated for their response to the prevailing races of Pst at the seedling and adult plant stages, the latter in replicated field trials at two sites in Ethiopia in 2011. About 28% of the SHWs exhibited immunity at the seedling stage while 56% and 83% were resistant to Pst at the adult plant stage at Meraro and Arsi Robe, respectively. A total of 27 SNPs in nine genomic regions (1BS, 2AS, 2BL, 3BL, 3DL, 5A, 5BL, 6DS and 7A) were linked with resistance to Pst at the seedling stage, while 38 SNPs on 18 genomic regions were associated with resistance at the adult plant stage. Six genomic regions were commonly detected at both locations using a mixed linear model corrected for population structure, kinship relatedness and adjusted for false discovery rate (FDR). The loci on chromosome regions 1AS, 3DL, 6DS and 7AL appeared to be novel QTL; our results confirm that resynthesized wheat involving its progenitor species is a rich source of new stripe (yellow) rust resistance that may be useful in choosing SHWs and incorporating diverse yellow rust (YR) resistance loci into locally adapted wheat cultivars. PMID:25153126

  3. Molecular and phenotypic characterization of seedling and adult plant leaf rust resistance in a world wheat collection.

    PubMed

    Dakouri, Abdulsalam; McCallum, Brent D; Radovanovic, Natasa; Cloutier, Sylvie

    2013-01-01

    Genetic resistance is the most effective approach to managing wheat leaf rust. The aim of this study was to characterize seedling and adult plant leaf rust resistance of a world wheat collection. Using controlled inoculation with ten races of Puccinia triticina, 14 seedling resistance genes were determined or postulated to be present in the collection. Lr1, Lr3, Lr10 and Lr20 were the most prevalent genes around the world while Lr9, Lr14b, Lr3ka and/or Lr30 and Lr26 were rare. To confirm some gene postulations, the collection was screened with gene-specific molecular markers for Lr1, Lr10, Lr21 and Lr34. Although possessing the Lr1 and/or Lr10 gene-specific marker, 51 accessions showed unexpected high infection types to P. triticina race BBBD. The collection was tested in the field, where rust resistance ranged from nearly immune or highly resistant with severity of 1 % and resistant host response to highly susceptible with severity of 84 % and susceptible host response. The majority of the accessions possessing the adult plant resistance (APR) gene Lr34 had a maximum rust severity of 0-35 %, similar to or better than accession RL6058, a Thatcher-Lr34 near-isogenic line. Many accessions displayed an immune response or a high level of resistance under field conditions, likely as a result of synergy between APR genes or between APR and seedling resistance genes. However, accessions with three or more seedling resistance genes had an overall lower field severity than those with two or fewer. Immune or highly resistant accessions are potential sources for improvement of leaf rust resistance. In addition, some lines were postulated to have known but unidentified genes/alleles or novel genes, also constituting potentially important sources of novel resistance. PMID:24078786

  4. The dissection and SSR mapping of a high-temperature adult-plant stripe rust resistance gene in American spring wheat cultivar Alturas

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stripe rust is one of major diseases in wheat production worldwide. The best economic and efficient method is to utilize resistant varieties. Alturas has high-temperature adult-plant resistance. In order to determine stripe rust resistance characteristics, resistance gene combination and molecular m...

  5. Genome Wide Association Study of Seedling and Adult Plant Leaf Rust Resistance in Elite Spring Wheat Breeding Lines

    PubMed Central

    Gao, Liangliang; Turner, M. Kathryn; Chao, Shiaoman; Kolmer, James; Anderson, James A.

    2016-01-01

    Leaf rust is an important disease, threatening wheat production annually. Identification of resistance genes or QTLs for effective field resistance could greatly enhance our ability to breed durably resistant varieties. We applied a genome wide association study (GWAS) approach to identify resistance genes or QTLs in 338 spring wheat breeding lines from public and private sectors that were predominately developed in the Americas. A total of 46 QTLs were identified for field and seedling traits and approximately 20–30 confer field resistance in varying degrees. The 10 QTLs accounting for the most variation in field resistance explained 26–30% of the total variation (depending on traits: percent severity, coefficient of infection or response type). Similarly, the 10 QTLs accounting for most of the variation in seedling resistance to different races explained 24–34% of the variation, after correcting for population structure. Two potentially novel QTLs (QLr.umn-1AL, QLr.umn-4AS) were identified. Identification of novel genes or QTLs and validation of previously identified genes or QTLs for seedling and especially adult plant resistance will enhance understanding of leaf rust resistance and assist breeding for resistant wheat varieties. We also developed computer programs to automate field and seedling rust phenotype data conversions. This is the first GWAS study of leaf rust resistance in elite wheat breeding lines genotyped with high density 90K SNP arrays. PMID:26849364

  6. Transcriptome Analysis Provides Insights into the Mechanisms Underlying Wheat Plant Resistance to Stripe Rust at the Adult Plant Stage

    PubMed Central

    Hao, Yingbin; Wang, Ting; Wang, Kang; Wang, Xiaojie; Fu, Yanping; Huang, Lili; Kang, Zhensheng

    2016-01-01

    Stripe rust (or yellow rust), which is caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most devastating wheat diseases worldwide. The wheat cultivar Xingzi 9104 (XZ) is an elite wheat germplasm that possesses adult plant resistance (APR), which is non–race-specific and durable. Thus, to better understand the mechanism underlying APR, we performed transcriptome sequencing of wheat seedlings and adult plants without Pst infection, and a total of 157,689 unigenes were obtained as a reference. In total, 2,666, 783 and 2,587 differentially expressed genes (DEGs) were found to be up- or down-regulated after Pst infection at 24, 48 and 120 hours post-inoculation (hpi), respectively, based on a comparison of Pst- and mock-infected plants. Among these unigenes, the temporal pattern of the up-regulated unigenes exhibited transient expression patterns during Pst infection, as determined through a Gene Ontology (GO) enrichment analysis. In addition, a Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that many biological processes, including phenylpropanoid biosynthesis, reactive oxygen species, photosynthesis and thiamine metabolism, which mainly control the mechanisms of lignification, reactive oxygen species and sugar, respectively, are involved in APR. In particular, the continuous accumulation of reactive oxygen species may potentially contribute to the ability of the adult plant to inhibit fungal growth and development. To validate the bioinformatics results, 6 candidate genes were selected for further functional identification using the virus-induced gene silencing (VIGS) system, and 4 candidate genes likely contribute to plant resistance against Pst infection. Our study provides new information concerning the transcriptional changes that occur during the Pst-wheat interaction at the adult stage and will help further our understanding of the detailed mechanisms underlying APR to Pst. PMID:26991894

  7. Expression of a Thatcher wheat adult plant stem rust resistance QTL on chromosome arm 2BL is enhanced by Lr34

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An F6 recombinant inbred line (RIL) spring wheat population derived from RL6071, a stem rust susceptible line and RL6058, a backcross line of Thatcher wheat with Lr34 that is highly resistant to stem rust, was evaluated for adult plant stem rust resistance in North Dakota in 1999, and in Kenya in 20...

  8. Mapping of adult plant stripe rust resistance genes in diploid A genome wheat species and their transfer to bread wheat.

    PubMed

    Chhuneja, Parveen; Kaur, Satinder; Garg, Tosh; Ghai, Meenu; Kaur, Simarjit; Prashar, M; Bains, N S; Goel, R K; Keller, Beat; Dhaliwal, H S; Singh, Kuldeep

    2008-02-01

    Stripe rust, caused by Puccinia striiformis West. f.sp. tritici, is one of the most damaging diseases of wheat worldwide. Forty genes for stripe rust resistance have been catalogued so far, but the majority of them are not effective against emerging pathotypes. Triticum monococcum and T. boeoticum have excellent levels of resistance to rusts, but so far, no stripe rust resistance gene has been identified or transferred from these species. A set of 121 RILs generated from a cross involving T. monococcum (acc. pau14087) and T. boeoticum (acc. pau5088) was screened for 3 years against a mixture of pathotypes under field conditions. The parental accessions were susceptible to all the prevalent pathotypes at the seedling stage, but resistant at the adult plant stage. Genetic analysis of the RIL population revealed the presence of two genes for stripe rust resistance, with one gene each being contributed by each of the parental lines. A linkage map with 169 SSR and RFLP loci generated from a set of 93 RILs was used for mapping these resistance genes. Based on phenotypic data for 3 years and the pooled data, two QTLs, one each in T. monococcum acc. pau14087 and T. boeoticum acc. pau5088, were detected for resistance in the RIL population. The QTL in T. monococcum mapped on chromosome 2A in a 3.6 cM interval between Xwmc407 and Xwmc170, whereas the QTL from T. boeoticum mapped on 5A in 8.9 cM interval between Xbarc151 and Xcfd12 and these were designated as QYrtm.pau-2A and QYrtb.pau-5A, respectively. Based on field data for 3 years, their R2 values were 14 and 24%, respectively. T. monococcum acc. pau14087 and three resistant RILs were crossed to hexaploid wheat cvs WL711 and PBW343, using T. durum as a bridging species with the objective of transferring these genes into hexaploid wheat. The B genome of T. durum suppressed resistance in the F1 plants, but with subsequent backcrossing one resistance gene could be transferred from one of the RILs to the hexaploid wheat

  9. QTL mapping of adult-plant resistances to stripe rust and leaf rust in Chinese wheat cultivar Bainong 64.

    PubMed

    Ren, Yan; Li, Zaifeng; He, Zhonghu; Wu, Ling; Bai, Bin; Lan, Caixia; Wang, Cuifen; Zhou, Gang; Zhu, Huazhong; Xia, Xianchun

    2012-10-01

    Stripe rust and leaf rust, caused by Puccinia striiformis Westend. f. sp. tritici Erikss. and P. triticina, respectively, are devastating fungal diseases of common wheat (Triticum aestivum L.). Chinese wheat cultivar Bainong 64 has maintained acceptable adult-plant resistance (APR) to stripe rust, leaf rust and powdery mildew for more than 10 years. The aim of this study was to identify quantitative trait loci/locus (QTL) for resistance to the two rusts in a population of 179 doubled haploid (DH) lines derived from Bainong 64 × Jingshuang 16. The DH lines were planted in randomized complete blocks with three replicates at four locations. Stripe rust tests were conducted using a mixture of currently prevalent P. striiformis races, and leaf rust tests were performed with P. triticina race THTT. Leaf rust severities were scored two or three times, whereas maximum disease severities (MDS) were recorded for stripe rust. Using bulked segregant analysis (BSA) and simple sequence repeat (SSR) markers, five independent loci for APR to two rusts were detected. The QTL on chromosomes 1BL and 6BS contributed by Bainong 64 conferred resistance to both diseases. The loci identified on chromosomes 7AS and 4DL had minor effects on stripe rust response, whereas another locus, close to the centromere on chromosome 6BS, had a significant effect only on leaf rust response. The loci located on chromosomes 1BL and 4DL also had significant effects on powdery mildew response. These were located at the same positions as the Yr29/Lr46 and Yr46/Lr67 genes, respectively. The multiple disease resistance locus for APR on chromosome 6BS appears to be new. All three genes and their closely linked molecular markers could be used in breeding wheat cultivars with durable resistance to multiple diseases. PMID:22806327

  10. Adult plant resistance to Puccinia triticina in a geographically diverse collection of Aegilops tauschii

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite extensive genetics and breeding research, effective control of leaf rust caused by Puccinia triticina Eriks., an important foliar disease of wheat, has not been achieved. This is mainly due to the widespread use of race-specific seedling resistance genes, which are rapidly overcome by new vi...

  11. Genetic analysis of adult plant, quantitative resistance to stripe rust in wheat cultivar 'Stephens' in multi-environment trials.

    PubMed

    Dolores Vazquez, M; James Peterson, C; Riera-Lizarazu, Oscar; Chen, Xianming; Heesacker, Adam; Ammar, Karim; Crossa, Jose; Mundt, Christopher C

    2012-01-01

    The wheat (Triticum aestivum L.) cultivar 'Stephens' has been grown commercially in the USA Pacific Northwest for 30 years. The durable resistance of 'Stephens' to stripe rust (Puccinia striiformis f. sp. tritici) was believed to be due to a combination of seedling and adult plant resistance genes. Multilocation field trials, diversity array technology (DArT), and simple sequence repeat (SSR) markers were used to identify quantitative trait loci (QTL) for resistance. Recombinant inbred lines were assessed for stripe rust response in eight locations/years, five in 2008 and three in 2009. The data from Mt. Vernon, WA, differed from all other environments, and composite interval mapping (CIM) identified three QTL, QYrst.orr-1AL, QYrst.orr-4BS, and QYrpl.orr-6AL, which accounted for 12, 11, and 6% of the phenotypic variance, respectively. CIM across the remaining six environments identified four main QTL. Two QTL, QYrst.orr-2BS.2 and QYrst.orr-7AS, were detected in five of six environments and explained 11 and 15% of the phenotypic variance, respectively. Two other QTL, QYrst.orr-2AS and QYrpl.orr-4BL, were detected across four and three of six environments, and explained 19 and 9% of the phenotypic variance, respectively. The susceptible parent 'Platte' contributed QYrpl.orr-4BL and QYrpl.orr-6AL, with the remaining QTL originating from 'Stephens'. For each environment, additional minor QTL were detected, each accounting for 6-10% of the phenotypic variance. Different QTL with moderate effects were identified in both 'Stephens' and 'Platte'. Significant QTL × environment interactions were evident, suggesting that specificity to plant stage, pathogen genotype, and/or temperature was important. PMID:21912857

  12. Mapping a Large Number of QTL for Durable Resistance to Stripe Rust in Winter Wheat Druchamp Using SSR and SNP Markers

    PubMed Central

    Hou, Lu; Chen, Xianming; Wang, Meinan; See, Deven R.; Chao, Shiaoman; Bulli, Peter; Jing, Jinxue

    2015-01-01

    Winter wheat Druchamp has both high-temperature adult-plant (HTAP) resistance and all-stage resistance to stripe rust caused by Puccinia striiformis f. sp. tritici (Pst). The HTAP resistance in Druchamp is durable as the variety has been resistant in adult-plant stage since it was introduced from France to the United States in late 1940s. To map the quantitative trait loci (QTL) for stripe rust resistance, an F8 recombinant inbred line (RIL) population from cross Druchamp × Michigan Amber was phenotyped for stripe rust response in multiple years in fields under natural infection and with selected Pst races under controlled greenhouse conditions, and genotyped with simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers. Composite interval mapping (CIM) identified eight HTAP resistance QTL and three all-stage resistance QTL. Among the eight HTAP resistance QTL, QYrdr.wgp-1BL.2 (explaining 2.36-31.04% variation), QYrdr.wgp-2BL (2.81–15.65%), QYrdr.wgp-5AL (2.27–17.22%) and QYrdr.wgp-5BL.2 (2.42–15.13%) were significant in all tests; and QYrdr.wgp-1BL.1 (1.94–10.19%), QYrdr.wgp-1DS (2.04–27.24%), QYrdr.wgp-3AL (1.78–13.85%) and QYrdr.wgp-6BL.2 (1.69–33.71%) were significant in some of the tests. The three all-stage resistance QTL, QYrdr.wgp-5BL.1 (5.47–36.04%), QYrdr.wgp-5DL (9.27–11.94%) and QYrdr.wgp-6BL.1 (13.07-20.36%), were detected based on reactions in the seedlings tested with certain Pst races. Among the eleven QTL detected in Druchamp, at least three (QYrdr.wgp-5DL for race-specific all-stage resistance and QYrdr.wgp-3AL and QYrdr.wgp-6BL.2 for race non-specific HTAP resistance) are new. All these QTL, especially those for durable HTAP resistance, and their closely linked molecular markers could be useful for developing wheat cultivars with durable resistance to stripe rust. PMID:25970329

  13. Mapping a Large Number of QTL for Durable Resistance to Stripe Rust in Winter Wheat Druchamp Using SSR and SNP Markers.

    PubMed

    Hou, Lu; Chen, Xianming; Wang, Meinan; See, Deven R; Chao, Shiaoman; Bulli, Peter; Jing, Jinxue

    2015-01-01

    Winter wheat Druchamp has both high-temperature adult-plant (HTAP) resistance and all-stage resistance to stripe rust caused by Puccinia striiformis f. sp. tritici (Pst). The HTAP resistance in Druchamp is durable as the variety has been resistant in adult-plant stage since it was introduced from France to the United States in late 1940s. To map the quantitative trait loci (QTL) for stripe rust resistance, an F8 recombinant inbred line (RIL) population from cross Druchamp × Michigan Amber was phenotyped for stripe rust response in multiple years in fields under natural infection and with selected Pst races under controlled greenhouse conditions, and genotyped with simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers. Composite interval mapping (CIM) identified eight HTAP resistance QTL and three all-stage resistance QTL. Among the eight HTAP resistance QTL, QYrdr.wgp-1BL.2 (explaining 2.36-31.04% variation), QYrdr.wgp-2BL (2.81-15.65%), QYrdr.wgp-5AL (2.27-17.22%) and QYrdr.wgp-5BL.2 (2.42-15.13%) were significant in all tests; and QYrdr.wgp-1BL.1 (1.94-10.19%), QYrdr.wgp-1DS (2.04-27.24%), QYrdr.wgp-3AL (1.78-13.85%) and QYrdr.wgp-6BL.2 (1.69-33.71%) were significant in some of the tests. The three all-stage resistance QTL, QYrdr.wgp-5BL.1 (5.47-36.04%), QYrdr.wgp-5DL (9.27-11.94%) and QYrdr.wgp-6BL.1 (13.07-20.36%), were detected based on reactions in the seedlings tested with certain Pst races. Among the eleven QTL detected in Druchamp, at least three (QYrdr.wgp-5DL for race-specific all-stage resistance and QYrdr.wgp-3AL and QYrdr.wgp-6BL.2 for race non-specific HTAP resistance) are new. All these QTL, especially those for durable HTAP resistance, and their closely linked molecular markers could be useful for developing wheat cultivars with durable resistance to stripe rust. PMID:25970329

  14. Comparative Analysis of Transcripts Associated to All-Stage Resistance and Adult-Plant Resistance to Stripe Rust in Wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stripe rust, caused by Puccinia striiformis f. sp. tritici, is a destructive disease of wheat worldwide. Genetic resistance is the preferred method for controlling stripe rust, of which two major types are race-specific and race non-specific resistance. Race-specific resistance includes the qualitat...

  15. Comparative analysis of transcripts associated to all-stage resistance and adult-plant resistance to stripe rust in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stripe rust, caused by Puccinia striiformis f. sp. tritici, is a destructive disease of wheat worldwide. Genetic resistance is the preferred method for controlling stripe rust, of which two major types are race-specific and race non-specific resistance. Race-specific resistance includes the qualitat...

  16. Influence of stripe rust infection on the photosynthetic characteristics and antioxidant system of susceptible and resistant wheat cultivars at the adult plant stage

    PubMed Central

    Chen, Yang-Er; Cui, Jun-Mei; Su, Yan-Qiu; Yuan, Shu; Yuan, Ming; Zhang, Huai-Yu

    2015-01-01

    Wheat stripe rust (Puccinia striiformis f. sp. tritici, Pst), is one of the most serious diseases of wheat (Triticum aestivum L.) worldwide. To gain a better understanding of the protective mechanism against stripe rust at the adult plant stage, the differences in photosystem II and antioxidant enzymatic systems between susceptible and resistant wheat in response to stripe rust disease (P. striiformis) were investigated. We found that chlorophyll fluorescence and the activities of the antioxidant enzymes were higher in resistant wheat than in susceptible wheat after stripe rust infection. Compared with the susceptible wheat, the resistant wheat accumulated a higher level of D1 protein and a lower level of reactive oxygen species after infection. Furthermore, our results demonstrate that D1 and light-harvesting complex II (LHCII) phosphorylation are involved in the resistance to stripe rust in wheat. The CP29 protein was phosphorylated under stripe rust infection, like its phosphorylation in other monocots under environmental stresses. More extensive damages occur on the thylakoid membranes in the susceptible wheat compared with the resistant wheat. The findings provide evidence that thylakoid protein phosphorylation and antioxidant enzyme systems play important roles in plant responses and defense to biotic stress. PMID:26442087

  17. Genome wide association study of seedling and adult plant leaf rust resistance in elite spring wheat breeding lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Leaf rust is an important disease, threatening wheat production annually. Identification of resistance genes or QTLs for effective field resistance could greatly enhance our ability to breed durably resistant varieties. We applied a genome wide association study (GWAS) approach to identify resista...

  18. Genome-Wide Linkage Mapping of QTL for Adult-Plant Resistance to Stripe Rust in a Chinese Wheat Population Linmai 2 × Zhong 892

    PubMed Central

    Liu, Jindong; He, Zhonghu; Wu, Ling; Bai, Bin; Wen, Weie; Xie, Chaojie; Xia, Xianchun

    2015-01-01

    Stripe rust is one of the most devastating diseases of wheat (Triticum aestivum) worldwide. Adult-plant resistance (APR) is an efficient approach to provide long-term protection of wheat from the disease. The Chinese winter wheat cultivar Zhong 892 has a moderate level of APR to stripe rust in the field. To determine the inheritance of the APR resistance in this cultivar, 273 F6 recombinant inbred lines (RILs) were developed from a cross between Linmai 2 and Zhong 892. The RILs were evaluated for maximum disease severity (MDS) in two sites during the 2011–2012, 2012–2013 and 2013–2014 cropping seasons, providing data for five environments. Illumina 90k SNP (single nucleotide polymorphism) chips were used to genotype the RILs and their parents. Composite interval mapping (CIM) detected eight QTL, namely QYr.caas-2AL, QYr.caas-2BL.3, QYr.caas-3AS, QYr.caas-3BS, QYr.caas-5DL, QYr.caas-6AL, QYr.caas-7AL and QYr.caas-7DS.1, respectively. All except QYr.caas-2BL.3 resistance alleles were contributed by Zhong 892. QYr.caas-3AS and QYr.caas-3BS conferred stable resistance to stripe rust in all environments, explaining 6.2–17.4% and 5.0–11.5% of the phenotypic variances, respectively. The genome scan of SNP sequences tightly linked to QTL for APR against annotated proteins in wheat and related cereals genomes identified two candidate genes (autophagy-related gene and disease resistance gene RGA1), significantly associated with stripe rust resistance. These QTL and their closely linked SNP markers, in combination with kompetitive allele specific PCR (KASP) technology, are potentially useful for improving stripe rust resistances in wheat breeding. PMID:26714310

  19. Characterization of a major QTL for adult plant resistance to stripe rust in US soft red winter wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stripe rust, caused by Puccinia striiformis f. sp. tritici, is an important disease of soft red winter wheat in the eastern region of the USA. Pioneer 26R61 has provided effective resistance to stripe rust for 10 years. To elucidate the genetic basis of the resistance, a mapping population of 178 re...

  20. Identification of Yr59 conferring high-temperature adult-plant resistance to stripe rust in wheat germplasm PI 178759

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most widespread and destructive wheat diseases worldwide. Resistant cultivars are the preferred means of control. The spring wheat germplasm ‘PI 178759’ originating from Iraq showed effective resistance to stripe rust in fie...

  1. Adult Plant Evaluation of Soybean Accessions for Resistance to Phakopsora pachyrhizi in the Field and Greenhouse in Paraguay

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soybean rust [Phakopsora pachyrhizi H. Sydow & Sydow] causes significant yield losses in soybean [Glycine max L.] in areas where it is endemic. Five hundred thirty-four soybean accessions from maturity groups (MG) III through IX, previously selected as potential sources of resistance to soybean rust...

  2. Identification and mapping of adult plant stripe rust resistance in soft red winter wheat cultivar USG 3555

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Little is known about the extent or diversity of resistance in soft red winter wheat (Triticum aestivum L.) to stripe rust, caused by the fungal pathogen Puccinia striiformis Westend. f.sp. tritici Eriks., as until recently, breeding programs in the eastern U.S. have not focused on this disease. Pr...

  3. QTL mapping of slow-rusting, adult plant resistance to race Ug99 of stem rust fungus in PBW343/Muu RIL population.

    PubMed

    Singh, Sukhwinder; Singh, Ravi P; Bhavani, Sridhar; Huerta-Espino, Julio; Eugenio, Lopez-Vera Eric

    2013-05-01

    Races of stem rust fungus pose a major threat to wheat production worldwide. We mapped adult plant resistance (APR) to Ug99 in 141 lines of a PBW343/Muu recombinant inbred lines (RILs) population by phenotyping them for three seasons at Njoro, Kenya in field trials and genotyping them with Diversity Arrays Technology (DArT) markers. Moderately susceptible parent PBW343 and APR parent Muu displayed mean stem rust severities of 66.6 and 5 %, respectively. The mean disease severity of RILs ranged from 1 to 100 %, with an average of 23.3 %. Variance components for stem rust severity were highly significant (p < 0.001) for RILs and seasons and the heritability (h (2)) for the disease ranged between 0.78 and 0.89. Quantitative trait loci (QTL) analysis identified four consistent genomic regions on chromosomes 2BS, 3BS, 5BL, and 7AS; three contributed by Muu (QSr.cim-2BS, QSr.cim-3BS and QSr.cim-7AS) and one (QSr.cim-5BL) derived from PBW343. RILs with flanking markers for these QTLs had significantly lower severities than those lacking the markers, and combinations of QTLs had an additive effect, significantly enhancing APR. The QTL identified on chromosome 3BS mapped to the matching region as the known APR gene Sr2. Four additional QTLs on chromosomes 1D, 3A, 4B, and 6A reduced disease severity significantly at least once in three seasons. Our results show a complex nature of APR to stem rust where Sr2 and other minor slow rusting resistance genes can confer a higher level of resistance when present together. PMID:23440380

  4. An introgression on wheat chromosome 4DL in RL6077 (Thatcher*6/PI 250413) confers adult plant resistance to stripe rust and leaf rust (Lr67).

    PubMed

    Hiebert, Colin W; Thomas, Julian B; McCallum, Brent D; Humphreys, D Gavin; DePauw, Ronald M; Hayden, Matthew J; Mago, Rohit; Schnippenkoetter, Wendelin; Spielmeyer, Wolfgang

    2010-10-01

    Adult plant resistance (APR) to leaf rust and stripe rust derived from the wheat (Triticum aestivum L.) line PI250413 was previously identified in RL6077 (=Thatcher*6/PI250413). The leaf rust resistance gene in RL6077 is phenotypically similar to Lr34 which is located on chromosome 7D. It was previously hypothesized that the gene in RL6077 could be Lr34 translocated to another chromosome. Hybrids between RL6077 and Thatcher and between RL6077 and 7DS and 7DL ditelocentric stocks were examined for first meiotic metaphase pairing. RL6077 formed chain quadrivalents and trivalents relative to Thatcher and Chinese Spring; however both 7D telocentrics paired only as heteromorphic bivalents and never with the multivalents. Thus, chromosome 7D is not involved in any translocation carried by RL6077. A genome-wide scan of SSR markers detected an introgression from chromosome 4D of PI250413 transferred to RL6077 through five cycles of backcrossing to Thatcher. Haplotype analysis of lines from crosses of Thatcher × RL6077 and RL6058 (Thatcher*6/PI58548) × RL6077 showed highly significant associations between introgressed markers (including SSR marker cfd71) and leaf rust resistance. In a separate RL6077-derived population, APR to stripe rust was also tightly linked with cfd71 on chromosome 4DL. An allele survey of linked SSR markers cfd71 and cfd23 on a set of 247 wheat lines from diverse origins indicated that these markers can be used to select for the donor segment in most wheat backgrounds. Comparison of RL6077 with Thatcher in field trials showed no effect of the APR gene on important agronomic or quality traits. Since no other known Lr genes exist on chromosome 4DL, the APR gene in RL6077 has been assigned the name Lr67. PMID:20552325

  5. The adult plant rust resistance loci Lr34/Yr18 and Lr46/Yr29 are important determinants of partial resistance to powdery mildew in bread wheat line Saar.

    PubMed

    Lillemo, M; Asalf, B; Singh, R P; Huerta-Espino, J; Chen, X M; He, Z H; Bjørnstad, A

    2008-05-01

    Powdery mildew, caused by Blumeria graminis f. sp. tritici is a major disease of wheat (Triticum aestivum L.) that can be controlled by resistance breeding. The CIMMYT bread wheat line Saar is known for its good level of partial and race non-specific resistance, and the aim of this study was to map QTLs for resistance to powdery mildew in a population of 113 recombinant inbred lines from a cross between Saar and the susceptible line Avocet. The population was tested over 2 years in field trials at two locations in southeastern Norway and once in Beijing, China. SSR markers were screened for association with powdery mildew resistance in a bulked segregant analysis, and linkage maps were created based on selected SSR markers and supplemented with DArT genotyping. The most important QTLs for powdery mildew resistance derived from Saar were located on chromosomes 7DS and 1BL and corresponded to the adult plant rust resistance loci Lr34/Yr18 and Lr46/Yr29. A major QTL was also located on 4BL with resistance contributed by Avocet. Additional QTLs were detected at 3AS and 5AL in the Norwegian testing environments and at 5BS in Beijing. The population was also tested for leaf rust (caused by Puccinia triticina) and stripe rust (caused by P. striiformis f. sp. tritici) resistance and leaf tip necrosis in Mexico. QTLs for these traits were detected on 7DS and 1BL at the same positions as the QTLs for powdery mildew resistance, and confirmed the presence of Lr34/Yr18 and Lr46/Yr29 in Saar. The powdery mildew resistance gene at the Lr34/Yr18 locus has recently been named Pm38. The powdery mildew resistance gene at the Lr46/Yr29 locus is designated as Pm39. PMID:18347772

  6. Identification and mapping of adult plant stripe rust resistance in soft red winter wheat VA00W-38, Pioneer brand 26R46, and Coker 9553

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since 2000, many of the previously effective wheat (Triticum aestivum L.) seedling stripe rust (pathogen Puccinia striiformis Westend. f.sp. tritici Eriks) resistance genes have become ineffective to the new more aggressive races of the pathogen. Because seedling resistance genes work on a gene for...

  7. Characterization of two adult-plant stripe rust resistance genes on chromosomes 3BS and 4BL in soft red winter wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stripe rust, caused by Puccinia striiformis f. sp. tritici, is an important foliar disease of soft red winter wheat (SRWW) in the eastern U.S. However, very few resistance genes have been characterized in the SRWW germplasm pool. The SRWW line VA96W-270 is known to be resistant to stripe rust race P...

  8. Mapping QTL conferring adult plant resistance to Ug99 in the University of Minnesota biparental population RB07/MN06113-8

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The emergence and spread of the Ug99 race group of the stem rust pathogen in the past decade has exposed the vulnerability of wheat to this disease. Discovery of novel and effective sources of resistance is vital to reduce losses. The experimental breeding line MN06113-8 and cultivar RB07 developed ...

  9. Characterization and Genetic Analysis of a Novel Light-Dependent Lesion Mimic Mutant, lm3, Showing Adult-Plant Resistance to Powdery Mildew in Common Wheat

    PubMed Central

    Wang, Fang; Wu, Wenying; Wang, Dongzhi; Yang, Wenlong; Sun, Jiazhu; Liu, Dongcheng; Zhang, Aimin

    2016-01-01

    Lesion mimics (LMs) that exhibit spontaneous disease-like lesions in the absence of pathogen attack might confer enhanced plant disease resistance to a wide range of pathogens. The LM mutant, lm3 was derived from a single naturally mutated individual in the F1 population of a 3-1/Jing411 cross, backcrossed six times with 3–1 as the recurrent parent and subsequently self-pollinated twice. The leaves of young seedlings of the lm3 mutant exhibited small, discrete white lesions under natural field conditions. The lesions first appeared at the leaf tips and subsequently expanded throughout the entire leaf blade to the leaf sheath. The lesions were initiated through light intensity and day length. Histochemical staining revealed that lesion formation might reflect programmed cell death (PCD) and abnormal accumulation of reactive oxygen species (ROS). The chlorophyll content in the mutant was significantly lower than that in wildtype, and the ratio of chlorophyll a/b was increased significantly in the mutant compared with wildtype, indicating that lm3 showed impairment of the biosynthesis or degradation of chlorophyll, and that Chlorophyll b was prone to damage during lesion formation. The lm3 mutant exhibited enhanced resistance to wheat powdery mildew fungus (Blumeria graminis f. sp. tritici; Bgt) infection, which was consistent with the increased expression of seven pathogenesis-related (PR) and two wheat chemically induced (WCI) genes involved in the defense-related reaction. Genetic analysis showed that the mutation was controlled through a single partially dominant gene, which was closely linked to Xbarc203 on chromosome 3BL; this gene was delimited to a 40 Mb region between SSR3B450.37 and SSR3B492.6 using a large derived segregating population and the available Chinese Spring chromosome 3B genome sequence. Taken together, our results provide information regarding the identification of a novel wheat LM gene, which will facilitate the additional fine-mapping and

  10. Characterization and Genetic Analysis of a Novel Light-Dependent Lesion Mimic Mutant, lm3, Showing Adult-Plant Resistance to Powdery Mildew in Common Wheat.

    PubMed

    Wang, Fang; Wu, Wenying; Wang, Dongzhi; Yang, Wenlong; Sun, Jiazhu; Liu, Dongcheng; Zhang, Aimin

    2016-01-01

    Lesion mimics (LMs) that exhibit spontaneous disease-like lesions in the absence of pathogen attack might confer enhanced plant disease resistance to a wide range of pathogens. The LM mutant, lm3 was derived from a single naturally mutated individual in the F1 population of a 3-1/Jing411 cross, backcrossed six times with 3-1 as the recurrent parent and subsequently self-pollinated twice. The leaves of young seedlings of the lm3 mutant exhibited small, discrete white lesions under natural field conditions. The lesions first appeared at the leaf tips and subsequently expanded throughout the entire leaf blade to the leaf sheath. The lesions were initiated through light intensity and day length. Histochemical staining revealed that lesion formation might reflect programmed cell death (PCD) and abnormal accumulation of reactive oxygen species (ROS). The chlorophyll content in the mutant was significantly lower than that in wildtype, and the ratio of chlorophyll a/b was increased significantly in the mutant compared with wildtype, indicating that lm3 showed impairment of the biosynthesis or degradation of chlorophyll, and that Chlorophyll b was prone to damage during lesion formation. The lm3 mutant exhibited enhanced resistance to wheat powdery mildew fungus (Blumeria graminis f. sp. tritici; Bgt) infection, which was consistent with the increased expression of seven pathogenesis-related (PR) and two wheat chemically induced (WCI) genes involved in the defense-related reaction. Genetic analysis showed that the mutation was controlled through a single partially dominant gene, which was closely linked to Xbarc203 on chromosome 3BL; this gene was delimited to a 40 Mb region between SSR3B450.37 and SSR3B492.6 using a large derived segregating population and the available Chinese Spring chromosome 3B genome sequence. Taken together, our results provide information regarding the identification of a novel wheat LM gene, which will facilitate the additional fine-mapping and

  11. Shrub control by browsing: Targeting adult plants

    NASA Astrophysics Data System (ADS)

    da Silveira Pontes, Laíse; Magda, Danièle; Gleizes, Benoît; Agreil, Cyril

    2016-01-01

    Reconciling the well known benefits of shrubs for forage with environmental goals, whilst preventing their dominance, is a major challenge in rangeland management. Browsing may be an economical solution for shrubby rangelands as herbivore browsing has been shown to control juvenile shrub growth. Less convincing results have been obtained for adult plants, and long-term experiments are required to investigate the cumulative effects on adult plants. We therefore assessed the impact of different levels of browsing intensity on key demographic parameters for a major dominant shrub species (broom, Cytisus scoparius), focusing on adult plants. We assigned individual broom plants to one of three age classes: 3-5 years (young adults); 5-7 years (adults); and 7-9 years (mature adults). These plants were then left untouched or had 50% or 90% of their total edible stem biomass removed in simulated low-intensity and high-intensity browsing treatments, respectively. Morphological, survival and fecundity data were collected over a period of four years. Browsing affected the morphology of individual plants, promoting changes in subsequent regrowth, and decreasing seed production. The heavily browsed plants were 17% shorter, 32% narrower, and their twigs were 28% shorter. Light browsing seemed to control the growth of young adult plants more effectively than that of older plants. Reproductive output was considerably lower than for control plants after light browsing, and almost 100% lower after heavy browsing. High-intensity browsing had a major effect on survival causing high levels of plant mortality. We conclude that suitable browsing practices could be used to modify adult shrub demography in the management of shrub dominance and forage value.

  12. Aerosol source attributions and source-receptor relationships across the Northern Hemisphere ---- initial results from HTAP2 model experiments

    NASA Astrophysics Data System (ADS)

    Bian, H.; Chin, M.; Kucsera, T. L.; Torres, O.; Pan, X.

    2014-12-01

    Emissions and long-range transport of air pollution pose major concerns on air quality and climate change. To better assess the impact of intercontinental transport of air pollution on regional and global air quality, ecosystems, and near-term climate change, the UN Task Force on Hemispheric Transport of Air Pollution (HTAP) is organizing a phase II activity (HTAP2) that includes global and regional model experiments and data analysis, focusing on ozone and aerosols. This study presents the initial results of HTAP2 global aerosol modeling experiments. We will (a) evaluate the model results with surface and aircraft measurements, (b) examine the relative contributions of regional emission and extra-regional source on surface PM concentrations and column aerosol optical depth (AOD) over several NH pollution and dust source regions and the Arctic, and (c) quantify the source-receptor relationships in the pollution regions that reflect the sensitivity of regional aerosol amount to the regional and extra-regional emission reductions.

  13. MIX: a mosaic Asian anthropogenic emission inventory for the MICS-Asia and the HTAP projects

    NASA Astrophysics Data System (ADS)

    Li, M.; Zhang, Q.; Kurokawa, J.; Woo, J.-H.; He, K. B.; Lu, Z.; Ohara, T.; Song, Y.; Streets, D. G.; Carmichael, G. R.; Cheng, Y. F.; Hong, C. P.; Huo, H.; Jiang, X. J.; Kang, S. C.; Liu, F.; Su, H.; Zheng, B.

    2015-12-01

    An anthropogenic emission inventory for Asia is developed for the years 2008 and 2010 to support the Model Inter-Comparison Study for Asia (MICS-Asia) and the Task Force on Hemispheric Transport of Air Pollution (TF HTAP) projects by a mosaic of up-to-date regional emission inventories. Emissions are estimated for all major anthropogenic sources in 30 countries and regions in Asia. We conducted detailed comparisons of different regional emission inventories and incorporated the best-available ones for each region into the mosaic inventory at a uniform spatial and temporal resolution. We estimate the total Asian emissions of ten species in 2010 as follows: 51.3 Tg SO2, 52.1 Tg NOx, 336.6 Tg CO, 67.0 Tg NMVOC (non-methane volatile organic compounds), 28.8 Tg NH3, 31.7 Tg PM10, 22.7 Tg PM2.5, 3.5 Tg BC, 8.3 Tg OC and 17.3 Pg CO2. Emissions from China and India dominate the emissions of Asia for most of the species. We also estimated Asian emissions in 2006 using the same methodology of MIX. The relative change rates of Asian emissions for the period of 2006-2010 are estimated as follows: -8.0 % for SO2, +19 % for NOx, +4 % for CO, +15 % for NMVOC, +2 % for NH3, -3 % for PM10, -2 % for PM2.5, +6 % for BC, +2 % for OC and +20 % for CO2. Model-ready speciated NMVOC emissions for SAPRC-99 and CB05 mechanisms were developed following a profile-assignment approach. Monthly gridded emissions at a spatial resolution of 0.25° × 0.25° are developed and can be accessed from http://www.meicmodel.org/dataset-mix.

  14. Evaluation of Pakistan wheat germplasms for stripe rust resistance using molecular markers.

    PubMed

    Sobia, Tabassum; Muhammad, Ashraf; Chen, XianMing

    2010-09-01

    Wheat production in Pakistan is seriously constrained due to rust diseases and stripe rust (yellow) caused by Puccinia striiformis f. sp. tritici, which could limit yields. Thus development and cultivation of genetically diverse and resistant varieties is the most sustainable solution to overcome these diseases. The first objective of the present study was to evaluate 100 Pakistan wheat cultivars that have been grown over the past 60 years. These cultivars were inoculated at the seedling stage with two virulent stripe rust isolates from the United States and two from Pakistan. None of the wheat cultivars were resistant to all tested stripe rust isolates, and 16% of cultivars were susceptible to the four isolates at the seedling stage. The data indicated that none of the Pakistan wheat cultivars contained either Yr5 or Yr15 genes that were considered to be effective against most P. striiformis f. sp. tritici isolates from around the world. Several Pakistan wheat cultivars may have gene Yr10, which is effective against isolate PST-127 but ineffective against PST-116. It is also possible that these cultivars may have other previously unidentified genes or gene combinations. The second objective was to evaluate the 100 Pakistan wheat cultivars for stripe rust resistance during natural epidemics in Pakistan and Washington State, USA. It was found that a higher frequency of resistance was present under field conditions compared with greenhouse conditions. Thirty genotypes (30% of germplasms) were found to have a potentially high temperature adult plant (HTAP) resistance. The third objective was to determine the genetic diversity in Pakistan wheat germplasms using molecular markers. This study was based on DNA fingerprinting using resistance gene analog polymorphism (RGAP) marker analysis. The highest polymorphism detected with RGAP primer pairs was 40%, 50% and 57% with a mean polymorphism of 36%. A total of 22 RGAP markers were obtained in this study. RGAP, simple

  15. Source Attribution of Near-surface Ozone in the Western US: Improved Estimates by TF HTAP2 Multi-model Experiment and Multi-scale Chemical Data Assimilation

    NASA Astrophysics Data System (ADS)

    Huang, M.; Bowman, K. W.; Carmichael, G. R.; Lee, M.; Park, R.; Henze, D. K.; Chai, T.; Flemming, J.; Lin, M.; Weinheimer, A. J.; Wisthaler, A.; Jaffe, D. A.

    2014-12-01

    Near-surface ozone in the western US can be sensitive to transported background pollutants from the free troposphere over the eastern Pacific, as well as various local emissions sources. Accurately estimating ozone source contributions in this region has strong policy-relevant significance as the air quality standards tend to go down. Here we improve modeled contributions from local and non-local sources to western US ozone base on the HTAP2 (Task Force on Hemispheric Transport of Air Pollution) multi-model experiment, along with multi-scale chemical data assimilation. We simulate western US air quality using the STEM regional model on a 12 km horizontal resolution grid, during the NASA ARCTAS field campaign period in June 2008. STEM simulations use time-varying boundary conditions downscaled from global GEOS-Chem model simulations. Standard GEOS-Chem simulation overall underpredicted ozone at 1-5 km in the eastern Pacific, resulting in underestimated contributions from the transported background pollutants to surface ozone inland. These negative biases can be reduced by using the output from several global models that support the HTAP2 experiment, which all ran with the HTAP2 harmonized emission inventory and also calculated the contributions from east Asian anthropogenic emissions. We demonstrate that the biases in GEOS-Chem boundary conditions can be more efficiently reduced via assimilating satellite ozone profiles from the Tropospheric Emission Spectrometer (TES) instrument using the three dimensional variational (3D-Var) approach. Base upon these TES-constrained GEOS-Chem boundary conditions, we then update regional nitrogen dioxide and isoprene emissions in STEM through the four dimensional variational (4D-Var) assimilation of the Ozone Monitoring Instrument (OMI) nitrogen dioxide columns and the NASA DC-8 aircraft isoprene measurements. The 4D-Var assimilation spatially redistributed the emissions of nitrogen oxides and isoprene from various US sources, and

  16. HTAP_v2.2: a mosaic of regional and global emission grid maps for 2008 and 2010 to study hemispheric transport of air pollution

    NASA Astrophysics Data System (ADS)

    Janssens-Maenhout, G.; Crippa, M.; Guizzardi, D.; Dentener, F.; Muntean, M.; Pouliot, G.; Keating, T.; Zhang, Q.; Kurokawa, J.; Wankmüller, R.; Denier van der Gon, H.; Kuenen, J. J. P.; Klimont, Z.; Frost, G.; Darras, S.; Koffi, B.; Li, M.

    2015-10-01

    The mandate of the Task Force Hemispheric Transport of Air Pollution (TF HTAP) under the Convention on Long-Range Transboundary Air Pollution (CLRTAP) is to improve the scientific understanding of the intercontinental air pollution transport, to quantify impacts on human health, vegetation and climate, to identify emission mitigation options across the regions of the Northern Hemisphere, and to guide future policies on these aspects. The harmonization and improvement of regional emission inventories is imperative to obtain consolidated estimates on the formation of global-scale air pollution. An emissions data set has been constructed using regional emission grid maps (annual and monthly) for SO2, NOx, CO, NMVOC, NH3, PM10, PM2.5, BC and OC for the years 2008 and 2010, with the purpose of providing consistent information to global and regional scale modelling efforts. This compilation of different regional gridded inventories - including that of the Environmental Protection Agency (EPA) for USA, the EPA and Environment Canada (for Canada), the European Monitoring and Evaluation Programme (EMEP) and Netherlands Organisation for Applied Scientific Research (TNO) for Europe, and the Model Inter-comparison Study for Asia (MICS-Asia III) for China, India and other Asian countries - was gap-filled with the emission grid maps of the Emissions Database for Global Atmospheric Research (EDGARv4.3) for the rest of the world (mainly South America, Africa, Russia and Oceania). Emissions from seven main categories of human activities (power, industry, residential, agriculture, ground transport, aviation and shipping) were estimated and spatially distributed on a common grid of 0.1° × 0.1° longitude-latitude, to yield monthly, global, sector-specific grid maps for each substance and year. The HTAP_v2.2 air pollutant grid maps are considered to combine latest available regional information within a complete global data set. The disaggregation by sectors, high spatial and

  17. HTAP_v2: a mosaic of regional and global emission gridmaps for 2008 and 2010 to study hemispheric transport of air pollution

    NASA Astrophysics Data System (ADS)

    Janssens-Maenhout, G.; Crippa, M.; Guizzardi, D.; Dentener, F.; Muntean, M.; Pouliot, G.; Keating, T.; Zhang, Q.; Kurokawa, J.; Wankmüller, R.; Denier van der Gon, H.; Klimont, Z.; Frost, G.; Darras, S.; Koffi, B.

    2015-04-01

    The mandate of the Task Force Hemispheric Transport of Air Pollution (HTAP) under the Convention on Long-Range Transboundary Air Pollution (CLRTAP) is to improve the scientific understanding of the intercontinental air pollution transport, to quantify impacts on human health, vegetation and climate, to identify emission mitigation options across the regions of the Northern Hemisphere, and to guide future policies on these aspects. The harmonization and improvement of regional emission inventories is imperative to obtain consolidated estimates on the formation of global-scale air pollution. An emissions dataset has been constructed using regional emission gridmaps (annual and monthly) for SO2, NOx, CO, NMVOC, NH3, PM10, PM2.5, BC and OC for the years 2008 and 2010, with the purpose of providing consistent information to global and regional scale modelling efforts. This compilation of different regional gridded inventories, including the Environmental Protection Agency (EPA)'s for USA, EPA and Environment Canada's for Canada, the European Monitoring and Evaluation Programme (EMEP) and Netherlands Organisation for Applied Scientific Research (TNO)'s for Europe, and the Model Inter-comparison Study in Asia (MICS-Asia)'s for China, India and other Asian countries, was gap-filled with the emission gridmaps of the Emissions Database for Global Atmospheric Research (EDGARv4.3) for the rest of the world (mainly South-America, Africa, Russia and Oceania). Emissions from seven main categories of human activities (power, industry, residential, agriculture, ground transport, aviation and shipping) were estimated and spatially distributed on a common grid of 0.1° × 0.1° longitude-latitude, to yield monthly, global, sector-specific gridmaps for each substance and year. The HTAP_v2.2 air pollutant gridmaps are considered to combine latest available regional information within a complete global dataset. The disaggregation by sectors, high spatial and temporal resolution and

  18. A HTAP Multi-Model Assessment of the Influence of Regional Anthropogenic Emission Reductions on Aerosol Direct Radiative Forcing and the Role of Intercontinental Transport

    NASA Technical Reports Server (NTRS)

    Yu, Hongbin; Chin, Mian; West, J. Jason; Atherton, Cynthia S.; Bellouin, Nicolas; Bergmann, Dan; Bey, Isabelle; Bian, Huisheng; Diehl, Thomas; Forberth, Gerd; Hess, Peter; Schulz, Michael; Shindell, Drew; Takemura, Toshihiko; Tan, Qian

    2012-01-01

    In this study, we assess changes of aerosol optical depth (AOD) and direct radiative forcing (DRF) in response to the reduction of anthropogenic emissions in four major pollution regions in the northern hemisphere by using results from 10 global chemical transport models in the framework of the Hemispheric Transport of Air Pollution (HTAP). The multi-model results show that on average, a 20% reduction of anthropogenic emissions in North America, Europe, East Asia and South Asia lowers the global mean AOD and DRF by about 9%, 4%, and 10% for sulfate, organic matter, and black carbon aerosol, respectively. The impacts of the regional emission reductions on AOD and DRF extend well beyond the source regions because of intercontinental transport. On an annual basis, intercontinental transport accounts for 10-30% of the overall AOD and DRF in a receptor region, with domestic emissions accounting for the remainder, depending on regions and species. While South Asia is most influenced by import of sulfate aerosol from Europe, North America is most influenced by import of black carbon from East Asia. Results show a large spread among models, highlighting the need to improve aerosol processes in models and evaluate and constrain models with observations.

  19. Adult plant development in triticale (× triticosecale wittmack) is controlled by dynamic genetic patterns of regulation.

    PubMed

    Würschum, Tobias; Liu, Wenxin; Alheit, Katharina V; Tucker, Matthew R; Gowda, Manje; Weissmann, Elmar A; Hahn, Volker; Maurer, Hans Peter

    2014-09-01

    Many biologically and agronomically important traits are dynamic and show temporal variation. In this study, we used triticale (× Triticosecale Wittmack) as a model crop to assess the genetic dynamics underlying phenotypic plasticity of adult plant development. To this end, a large mapping population with 647 doubled haploid lines derived from four partially connected families from crosses among six parents was scored for developmental stage at three different time points. Using genome-wide association mapping, we identified main effect and epistatic quantitative trait loci (QTL) at all three time points. Interestingly, some of these QTL were identified at all time points, whereas others appear to only contribute to the genetic architecture at certain developmental stages. Our results illustrate the temporal contribution of QTL to the genetic control of adult plant development and more generally, the temporal genetic patterns of regulation that underlie dynamic traits. PMID:25237110

  20. Regeneration of plantlets from the callus of stem segments of adult plants of Ficus religiosa L.

    PubMed

    Jaiswal, V S; Narayan, P

    1985-10-01

    Stem segments of adult plants of Ficus religiosa L. cultured on MS medium containing 1.0 mg/l 2,4-D produced callus. Shoots were regenerated when the induced calli were transferred to medium supplemented with 0.05 to 2.0 mg/l BAP. Callus derived shoots produced roots and developed into plantlets when transferred to medium supplemented with 1.0 mg/l NAA. PMID:24253982

  1. Comparison of cell death and accumulation of reactive oxygen species in wheat lines with or without Yr36 responding to Puccinia striiformis f. sp. tritici under low and high temperatures at seedling and adult-plant stages.

    PubMed

    Li, Hui; Ren, Bin; Kang, Zhensheng; Huang, Lili

    2016-05-01

    Yr36 is an important gene conferring resistance to stripe rust of wheat caused by Puccinia striiformis f. sp. tritici (Pst). To determine if the Yr36 resistance is correlated to reactive oxygen species (ROS) burst and cell death, wheat near-isogenic lines with (UC1041 + Yr36) and without (UC1041) the gene were histologically characterized for response to Pst infection. Yr36 conferred stripe rust resistance at both seedling and adult-plant stages when the gene line was tested with Pst race CYR29 at a high-temperature (HT) cycle (12 °C at night and 33 °C during the day). At the HT cycle, the growth of secondary hyphae was obviously suppressed in both seedlings and adult plants of UC1041 + Yr36 compared with those of UC1041. The percentages of infection sites with necrotic host cells in UC1041 + Yr36 were significantly higher than UC1041 60 hours after inoculation (hai) at both seedling and adult-plant stages. Mesophyll cell death in the inoculated UC1041 + Yr36 leaves at the HT cycle was stronger than at a low-temperature (LT) cycle (12 °C at night and 18 °C during the day). At the HT cycle, the level of ROS burst started increasing in the inoculated leaves of UC1041 + Yr36 when Pst hyphae started differentiating and extending, and simultaneously, the number of penetration sites with hypersensitive cell death was also increasing. The results indicate that Yr36 product affects the ROS accumulation and cell death of the host in interaction of wheat with Pst. PMID:26070270

  2. Air quality simulation over South Asia using Hemispheric Transport of Air Pollution version-2 (HTAP-v2) emission inventory and Model for Ozone and Related chemical Tracers (MOZART-4)

    NASA Astrophysics Data System (ADS)

    Surendran, Divya E.; Ghude, Sachin D.; Beig, G.; Emmons, L. K.; Jena, Chinmay; Kumar, Rajesh; Pfister, G. G.; Chate, D. M.

    2015-12-01

    This study presents the distribution of tropospheric ozone and related species for South Asia using the Model for Ozone and Related chemical Tracers (MOZART-4) and Hemispheric Transport of Air Pollution version-2 (HTAP-v2) emission inventory. The model present-day simulated ozone (O3), carbon monoxide (CO) and nitrogen dioxide (NO2) are evaluated against surface-based, balloon-borne and satellite-based (MOPITT and OMI) observations. The model systematically overestimates surface O3 mixing ratios (range of mean bias about: 1-30 ppbv) at different ground-based measurement sites in India. Comparison between simulated and observed vertical profiles of ozone shows a positive bias from the surface up to 600 hPa and a negative bias above 600 hPa. The simulated seasonal variation in surface CO mixing ratio is consistent with the surface observations, but has a negative bias of about 50-200 ppb which can be attributed to a large part to the coarse model resolution. In contrast to the surface evaluation, the model shows a positive bias of about 15-20 × 1017 molecules/cm2 over South Asia when compared to satellite derived CO columns from the MOPITT instrument. The model also overestimates OMI retrieved tropospheric column NO2 abundance by about 100-250 × 1013 molecules/cm2. A response to 20% reduction in all anthropogenic emissions over South Asia shows a decrease in the anuual mean O3 mixing ratios by about 3-12 ppb, CO by about 10-80 ppb and NOX by about 3-6 ppb at the surface level. During summer monsoon, O3 mixing ratios at 200 hPa show a decrease of about 6-12 ppb over South Asia and about 1-4 ppb over the remote northern hemispheric western Pacific region.

  3. The Effects of Cadmium-Zinc Interactions on Biochemical Responses in Tobacco Seedlings and Adult Plants

    PubMed Central

    Tkalec, Mirta; Štefanić, Petra Peharec; Cvjetko, Petra; Šikić, Sandra; Pavlica, Mirjana; Balen, Biljana

    2014-01-01

    The objective of the present study was to investigate the effects of cadmium-zinc (Cd-Zn) interactions on their uptake, oxidative damage of cell macromolecules (lipids, proteins, DNA) and activities of antioxidative enzymes in tobacco seedlings as well as roots and leaves of adult plants. Seedlings and plants were exposed to Cd (10 µM and 15 µM) and Zn (25 µM and 50 µM) as well as their combinations (10 µM or 15 µM Cd with either 25 µM or 50 µM Zn). Measurement of metal accumulation exhibited that Zn had mostly positive effect on Cd uptake in roots and seedlings, while Cd had antagonistic effect on Zn uptake in leaves and roots. According to examined oxidative stress parameters, in seedlings and roots individual Cd treatments induced oxidative damage, which was less prominent in combined treatments, indicating that the presence of Zn alleviates oxidative stress. However, DNA damage found in seedlings, and lower glutathione reductase (GR) and superoxide dismutase (SOD) activity recorded in both seedlings and roots, after individual Zn treatments, indicate that Zn accumulation could impose toxic effects. In leaves, oxidative stress was found after exposure to Cd either alone or in combination with Zn, thus implying that in this tissue Zn did not have alleviating effects. In conclusion, results obtained in different tobacco tissues suggest tissue-dependent Cd-Zn interactions, which resulted in activation of different mechanisms involved in the protection against metal stress. PMID:24475312

  4. Resistance to Ug99 stem rust in six bread wheat cultivars maps to chromosome 6DS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over 80% of wheat area worldwide is currently grown to varieties that are susceptible to the Ug99 race group of the stem rust fungus. Wheat lines Niini, Tinkio, Coni, Pfunye, Blouk and Ripper were resistant to Ug99 at the seedling and adult plant stages. We mapped stem rust resistance in populations...

  5. Gene expression patterns of wheat rust resistance gene Lr34/Yr18 indicate novel mode of action

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Lr34/Yr18 resistance gene provides durable, adult-plant, slow-rusting resistance to leaf rust and yellow rust of wheat. Patterns of gene expression were examined by microarray analysis in inoculated and mock-inoculated flag leaves of two pairs of near isogenic lines for Lr34/Yr18 (Thatcher/Thatc...

  6. TaXA21-A1 on chromosome 5AL is associated with resistance to multiple pests in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A quantitative trait locus QYr.osu-5A on the long arm of chromosome 5A in bread wheat (Triticum aestivum L., 2n=6x=42; AABBDD) was previously reported to confer consistent resistance in adult plants to predominant stripe rust races, but the gene causing the quantitative trait locus (QTL) is not know...

  7. The past, present and future of breeding rust resistant wheat

    PubMed Central

    Ellis, Jeffrey G.; Lagudah, Evans S.; Spielmeyer, Wolfgang; Dodds, Peter N.

    2014-01-01

    Two classes of genes are used for breeding rust resistant wheat. The first class, called R (for resistance) genes, are pathogen race specific in their action, effective at all plant growth stages and probably mostly encode immune receptors of the nucleotide binding leucine rich repeat (NB-LRR) class. The second class is called adult plant resistance genes (APR) because resistance is usually functional only in adult plants, and, in contrast to most R genes, the levels of resistance conferred by single APR genes are only partial and allow considerable disease development. Some but not all APR genes provide resistance to all isolates of a rust pathogen species and a subclass of these provides resistance to several fungal pathogen species. Initial indications are that APR genes encode a more heterogeneous range of proteins than R proteins. Two APR genes, Lr34 and Yr36, have been cloned from wheat and their products are an ABC transporter and a protein kinase, respectively. Lr34 and Sr2 have provided long lasting and widely used (durable) partial resistance and are mainly used in conjunction with other R and APR genes to obtain adequate rust resistance. We caution that some APR genes indeed include race specific, weak R genes which may be of the NB-LRR class. A research priority to better inform rust resistance breeding is to characterize further APR genes in wheat and to understand how they function and how they interact when multiple APR and R genes are stacked in a single genotype by conventional and GM breeding. An important message is do not be complacent about the general durability of all APR genes. PMID:25505474

  8. Mapping Stripe Rust Resistance in a BrundageXCoda Winter Wheat Recombinant Inbred Line Population

    PubMed Central

    Case, Austin J.; Naruoka, Yukiko; Chen, Xianming; Garland-Campbell, Kimberly A.; Zemetra, Robert S.; Carter, Arron H.

    2014-01-01

    A recombinant inbred line (RIL) mapping population developed from a cross between winter wheat (Triticum aestivum L.) cultivars Coda and Brundage was evaluated for reaction to stripe rust (caused by Puccinia striiformis f. sp. tritici). Two hundred and sixty eight RIL from the population were evaluated in replicated field trials in a total of nine site-year locations in the U.S. Pacific Northwest. Seedling reaction to stripe rust races PST-100, PST-114 and PST-127 was also examined. A linkage map consisting of 2,391 polymorphic DNA markers was developed covering all chromosomes of wheat with the exception of 1D. Two QTL on chromosome 1B were associated with adult plant and seedling reaction and were the most significant QTL detected. Together these QTL reduced adult plant infection type from a score of seven to a score of two reduced disease severity by an average of 25% and provided protection against race PST-100, PST-114 and PST-127 in the seedling stage. The location of these QTL and the race specificity provided by them suggest that observed effects at this locus are due to a complementation of the previously known but defeated resistances of the cultivar Tres combining with that of Madsen (the two parent cultivars of Coda). Two additional QTL on chromosome 3B and one on 5B were associated with adult plant reaction only, and a single QTL on chromosome 5D was associated with seedling reaction to PST-114. Coda has been resistant to stripe rust since its release in 2000, indicating that combining multiple resistance genes for stripe rust provides durable resistance, especially when all-stage resistance genes are combined in a fashion to maximize the number of races they protect against. Identified molecular markers will allow for an efficient transfer of these genes into other cultivars, thereby continuing to provide excellent resistance to stripe rust. PMID:24642574

  9. Association Analysis of Stem Rust Resistance in U.S. Winter Wheat

    PubMed Central

    Zhang, Dadong; Bowden, Robert L.; Yu, Jianming; Carver, Brett F.; Bai, Guihua

    2014-01-01

    Stem rust has become a renewed threat to global wheat production after the emergence and spread of race TTKSK (also known as Ug99) and related races from Africa. To elucidate U.S. winter wheat resistance genes to stem rust, association mapping was conducted using a panel of 137 lines from cooperative U.S. winter wheat nurseries from 2008 and simple sequence repeat (SSR) and sequence tagged site (STS) markers across the wheat genome. Seedling infection types were evaluated in a greenhouse experiment using six U.S. stem rust races (QFCSC, QTHJC, RCRSC, RKQQC, TPMKC and TTTTF) and TTKSK, and adult plant responses to bulked U.S. races were evaluated in a field experiment. A linearization algorithm was used to convert the qualitative Stakman scale seedling infection types for quantitative analysis. Association mapping successfully detected six known stem rust seedling resistance genes in U.S. winter wheat lines with frequencies: Sr6 (12%), Sr24 (9%), Sr31 (15%), Sr36 (9%), Sr38 (19%), and Sr1RSAmigo (8%). Adult plant resistance gene Sr2 was present in 4% of lines. SrTmp was postulated to be present in several hard winter wheat lines, but the frequency could not be accurately determined. Sr38 was the most prevalent Sr gene in both hard and soft winter wheat and was the most effective Sr gene in the adult plant field test. Resistance to TTKSK was associated with nine markers on chromosome 2B that were in linkage disequilibrium and all of the resistance was attributed to the Triticum timopheevii chromosome segment carrying Sr36. Potential novel rust resistance alleles were associated with markers Xwmc326-203 on 3BL, Xgwm160-195 and Xwmc313-225 on 4AL near Sr7, Xgwm495-182 on 4BL, Xwmc622-147 and Xgwm624-146 on 4DL, and Xgwm334-123 on 6AS near Sr8. Xwmc326-203 was associated with adult plant resistance to bulked U.S. races and Xgwm495-182 was associated with seedling resistance to TTKSK. PMID:25072699

  10. Resistance-Resistant Antibiotics

    PubMed Central

    Oldfield, Eric; Feng, Xinxin

    2014-01-01

    New antibiotics are needed because as drug resistance is increasing, the introduction of new antibiotics is decreasing. Here, we discuss six possible approaches to develop ‘resistance-resistant’ antibiotics. First, multi-target inhibitors in which a single compound inhibits more than one target may be easier to develop than conventional combination therapies with two new drugs. Second, inhibiting multiple targets in the same metabolic pathway is expected to be an effective strategy due to synergy. Third, discovering multiple-target inhibitors should be possible by using sequential virtual screening. Fourth, re-purposing existing drugs can lead to combinations of multi-target therapeutics. Fifth, targets need not be proteins. Sixth, inhibiting virulence factor formation and boosting innate immunity may also lead to decreased susceptibility to resistance. Although it is not possible to eliminate resistance, the approaches reviewed here offer several possibilities for reducing the effects of mutations and in some cases suggest that sensitivity to existing antibiotics may be restored, in otherwise drug resistant organisms. PMID:25458541

  11. Drug Resistance

    MedlinePlus

    HIV Treatment Drug Resistance (Last updated 3/1/2016; last reviewed 3/1/2016) Key Points As HIV multiplies in the ... the risk of drug resistance. What is HIV drug resistance? Once a person becomes infected with HIV, ...

  12. Antibiotic Resistance

    MedlinePlus

    ... lives. But there is a growing problem of antibiotic resistance. It happens when bacteria change and become able ... resistant to several common antibiotics. To help prevent antibiotic resistance Don't use antibiotics for viruses like colds ...

  13. Stripe rust resistance genes in the UK winter wheat cultivar Claire.

    PubMed

    Powell, N M; Lewis, C M; Berry, S T; Maccormack, R; Boyd, L A

    2013-06-01

    Stripe rust resistance in the winter wheat cultivar Claire had remained effective in the UK and Europe since its release in 1999 and consequently has been used extensively in wheat breeding programs. However, in 2012, reports indicated that this valuable resistance may now have been compromised. To characterise stripe rust resistance in Claire and determine which genes may still confer effective resistance a cross was made between Claire and the stripe rust susceptible cultivar Lemhi. A genetic linkage map, constructed using SSR, AFLP, DArT and NBS-AFLP markers had a total map length of 1,730 cM. To improve the definition of two quantitative trait loci (QTL) identified on the long arm of chromosome 2D further markers were developed from wheat EST. Stripe rust resistance was evaluated on adult plants under field and glasshouse conditions by measuring the extent of fungal growth and sporulation, percentage infection (Pi) and the necrotic/chlorotic responses of the plant to infection, infection type (IT). Four QTL contributing to stripe rust adult plant resistance (APR) were identified in Claire, QYr.niab-2D.1, QYr.niab-2D.2, QYr.niab-2B and QYr.niab-7B. For Pi QYr.niab-2D.1 explained up to 25.4 % of the phenotypic variation, QYr.niab-2D.2 up to 28.7 %, QYr.niab-2B up to 21.7 % and QYr.niab-7B up to 13.0 %. For IT the percentages of phenotypic variation explained were 23.4, 31.8, 17.2 and 12.6 %, respectively. In addition to the four QTL conferring APR in Claire, a race-specific, seedling expressed resistance gene was identified on chromosome 3B. PMID:23536048

  14. The wheat durable, multipathogen resistance gene Lr34 confers partial blast resistance in rice.

    PubMed

    Krattinger, Simon G; Sucher, Justine; Selter, Liselotte L; Chauhan, Harsh; Zhou, Bo; Tang, Mingzhi; Upadhyaya, Narayana M; Mieulet, Delphine; Guiderdoni, Emmanuel; Weidenbach, Denise; Schaffrath, Ulrich; Lagudah, Evans S; Keller, Beat

    2016-05-01

    The wheat gene Lr34 confers durable and partial field resistance against the obligate biotrophic, pathogenic rust fungi and powdery mildew in adult wheat plants. The resistant Lr34 allele evolved after wheat domestication through two gain-of-function mutations in an ATP-binding cassette transporter gene. An Lr34-like fungal disease resistance with a similar broad-spectrum specificity and durability has not been described in other cereals. Here, we transformed the resistant Lr34 allele into the japonica rice cultivar Nipponbare. Transgenic rice plants expressing Lr34 showed increased resistance against multiple isolates of the hemibiotrophic pathogen Magnaporthe oryzae, the causal agent of rice blast disease. Host cell invasion during the biotrophic growth phase of rice blast was delayed in Lr34-expressing rice plants, resulting in smaller necrotic lesions on leaves. Lines with Lr34 also developed a typical, senescence-based leaf tip necrosis (LTN) phenotype. Development of LTN during early seedling growth had a negative impact on formation of axillary shoots and spikelets in some transgenic lines. One transgenic line developed LTN only at adult plant stage which was correlated with lower Lr34 expression levels at seedling stage. This line showed normal tiller formation and more importantly, disease resistance in this particular line was not compromised. Interestingly, Lr34 in rice is effective against a hemibiotrophic pathogen with a lifestyle and infection strategy that is different from obligate biotrophic rusts and mildew fungi. Lr34 might therefore be used as a source in rice breeding to improve broad-spectrum disease resistance against the most devastating fungal disease of rice. PMID:26471973

  15. Genetic analysis of leaf rust resistance genes and associated markers in the durable resistant wheat cultivar Sinvalocho MA.

    PubMed

    Ingala, L; López, M; Darino, M; Pergolesi, M F; Diéguez, M J; Sacco, F

    2012-05-01

    In the cross of the durable leaf rust resistant wheat Sinvalocho MA and the susceptible line Gama6, four specific genes were identified: the seedling resistance gene Lr3, the adult plant resistance (APR) genes LrSV1 and LrSV2 coming from Sinvalocho MA, and the seedling resistance gene LrG6 coming from Gama6. Lr3 was previously mapped on 6BL in the same cross. LrSV1 was mapped on chromosome 2DS where resistance genes Lr22a and Lr22b have been reported. Results from rust reaction have shown that LrSV1 from Sinvalocho is not the same allele as Lr22b and an allelism test with Lr22a showed that they could be alleles or closely linked genes. LrSV1 was mapped in an 8.5-cM interval delimited by markers gwm296 distal and gwm261 proximal. Adult gene LrSV2 was mapped on chromosome 3BS, cosegregating with gwm533 in a 7.2-cM interval encompassed by markers gwm389 and gwm493, where other disease resistance genes are located, such as seedling gene Lr27 for leaf rust, Sr2 for stem rust, QTL Qfhs.ndsu-3BS for resistance to Fusarium gramineum and wheat powdery mildew resistance. The gene LrG6 was mapped on chromosome 2BL, with the closest marker gwm382 at 0.6 cM. Lines carrying LrSV1, LrSV2 and LrG6 tested under field natural infection conditions, showed low disease infection type and severity, suggesting that this kind of resistance can be explained by additive effects of APR and seedling resistance genes. The identification of new sources of resistance from South American land races and old varieties, supported by modern DNA technology, contributes to sustainability of agriculture through plant breeding. PMID:22278178

  16. Gene expression patterns in near isogenic lines for wheat rust resistance gene lr34/yr18.

    PubMed

    Hulbert, S H; Bai, J; Fellers, J P; Pacheco, M G; Bowden, R L

    2007-09-01

    ABSTRACT The Lr34/Yr18 resistance gene provides durable, adult-plant, slow rusting resistance to leaf rust, yellow rust, and several other diseases of wheat. Flag leaves may exhibit spontaneous leaf tip necrosis and tips are more resistant than leaf bases. Despite the importance of this gene, the mechanism of resistance is unknown. Patterns of expression for 55,052 transcripts were examined by microarray analysis in mock-inoculated flag leaves of two pairs of wheat near isogenic lines for Lr34/Yr18 (Jupateco 73S/Jupateco 73R and Thatcher/Thatcher-Lr34). The Thatcher isolines were also examined for patterns of expression after inoculation with leaf rust. Mock-inoculated leaf tips of resistant plants showed up-regulation of 57 transcripts generally associated with ABA inducibility, osmotic stress, cold stress, and/or seed maturation. Several transcripts may be useful as expression markers for Lr34/Yr18. Five transcripts were also up-regulated in resistant leaf bases. The possible role of these transcripts in resistance is discussed. In mock-inoculated plants, pathogenesis-related (PR) proteins were not up-regulated in resistant flag leaves compared with that in susceptible flag leaves. In inoculated plants, the same set of PR proteins was up-regulated in both resistant and susceptible flag leaves. However, expression was often higher in resistant plants, suggesting a possible role for Lr34/Yr18 in priming of defense responses. PMID:18944173

  17. Guiding deployment of resistance in cereals using evolutionary principles

    PubMed Central

    Burdon, Jeremy J; Barrett, Luke G; Rebetzke, Greg; Thrall, Peter H

    2014-01-01

    Genetically controlled resistance provides plant breeders with an efficient means of controlling plant disease, but this approach has been constrained by practical difficulties associated with combining many resistance genes together and strong evolutionary responses from pathogen populations leading to subsequent resistance breakdown. However, continuing advances in molecular marker technologies are revolutionizing the ability to rapidly and reliably manipulate resistances of all types – major gene, adult plant and quantitative resistance loci singly or multiply into individual host lines. Here, we argue that these advances provide major opportunities to deliberately design deployment strategies in cereals that can take advantage of the evolutionary pressures faced by target pathogens. Different combinations of genes deployed either within single host individuals or between different individuals within or among crops, can be used to reduce the size of pathogen populations and generate patterns of disruptive selection. This will simultaneously limit immediate epidemic development and reduce the probability of subsequent evolutionary change in the pathogen for broader infectivity or increased aggressiveness. The same general principles are relevant to the control of noncereal diseases, but the most efficacious controls will vary reflecting the range of genetic options available and their fit with specific ecology and life-history combinations. PMID:25067946

  18. A mutagenesis-derived broad-spectrum disease resistance locus in wheat.

    PubMed

    Campbell, Jackie; Zhang, Hongtao; Giroux, Michael J; Feiz, Leila; Jin, Yue; Wang, Meinan; Chen, Xianming; Huang, Li

    2012-07-01

    Wheat leaf rust, stem rust, stripe rust, and powdery mildew caused by the fungal pathogens Puccinia triticina, P. graminis f. sp. tritici, P. striiformis f. sp. tritici, and Blumeria graminis f. sp. tritici, respectively, are destructive diseases of wheat worldwide. Breeding durable disease resistance cultivars rely largely on continually introgressing new resistance genes, especially the genes with different defense mechanisms, into adapted varieties. Here, we describe a new resistance gene obtained by mutagenesis. The mutant, MNR220 (mutagenesis-derived new resistance), enhances resistance to three rusts and powdery mildew, with the characteristics of delayed disease development at the seedling stage and completed resistance at the adult plant stage. Genetic analysis demonstrated that the resistance in MNR220 is conferred by a single semidominant gene mapped on the short arm of chromosome 2B. Gene expression profiling of several pathogenesis-related genes indicated that MNR220 has an elevated and rapid pathogen-induced response. In addition to its potential use in breeding for resistance to multiple diseases, high-resolution mapping and cloning of the disease resistance locus in MNR220 may lead to a better understanding of the regulation of defense responses in wheat. PMID:22446929

  19. Antibiotic Resistance

    MedlinePlus

    ... For Consumers Consumer Information by Audience For Women Antibiotic Resistance Share Tweet Linkedin Pin it More sharing options ... these products really help. To Learn More about Antibiotic Resistance Get Smart About Antibiotics (Video) Fact Sheets and ...

  20. Host Resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Concepts covered in this chapter (for an undergraduate text book) • Disease resistance is a crucial trait for any crop plant. • The degree of disease resistance varies within plant populations. Much of this variation has a genetic basis. • Plant disease resistance can be broadly categorized into s...

  1. RESISTIVITY METHODS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Resistivity methods were among the first geophysical techniques developed. The basic concept originated with Conrad Schlumberger, who conducted the initial resistivity field tests in Normandy, France during 1912. The resistivity method, employed in its earliest and most conventional form, uses an ex...

  2. Antibiotic Resistance

    MedlinePlus

    Antibiotics are medicines that fight bacterial infections. Used properly, they can save lives. But there is a growing problem of antibiotic resistance. It happens when bacteria change and become able to resist the effects of an antibiotic. Using antibiotics can lead to resistance. ...

  3. Antimicrobial (Drug) Resistance

    MedlinePlus

    ... Antimicrobial (Drug) Resistance Antibiotic-Resistant Mycobacterium tuberculosis (TB) Methicillin-Resistant Staphylococcus aureus (MRSA) Vancomycin-Resistant Enterococci (VRE) Multidrug-Resistant Neisseria ...

  4. Resistant Hypertension.

    PubMed

    Doroszko, Adrian; Janus, Agnieszka; Szahidewicz-Krupska, Ewa; Mazur, Grzegorz; Derkacz, Arkadiusz

    2016-01-01

    Resistant hypertension is a severe medical condition which is estimated to appear in 9-18% of hypertensive patients. Due to higher cardiovascular risk, this disorder requires special diagnosis and treatment. The heterogeneous etiology, risk factors and comorbidities of resistant hypertension stand in need of sophisticated evaluation to confirm the diagnosis and select the best therapeutic options, which should consider lifestyle modifications as well as pharmacological and interventional treatment. After having excluded pseudohypertension, inappropriate blood pressure measurement and control as well as the white coat effect, suspicion of resistant hypertension requires an analysis of drugs which the hypertensive patient is treated with. According to one definition - ineffective treatment with 3 or more antihypertensive drugs including diuretics makes it possible to diagnose resistant hypertension. A multidrug therapy including angiotensin - converting enzyme inhibitors, angiotensin II receptor blockers, beta blockers, diuretics, long-acting calcium channel blockers and mineralocorticoid receptor antagonists has been demonstrated to be effective in resistant hypertension treatment. Nevertheless, optional, innovative therapies, e.g. a renal denervation or baroreflex activation, may create a novel pathway of blood pressure lowering procedures. The right diagnosis of this disease needs to eliminate the secondary causes of resistant hypertension e.g. obstructive sleep apnea, atherosclerosis and renal or hormonal disorders. This paper briefly summarizes the identification of the causes of resistant hypertension and therapeutic strategies, which may contribute to the proper diagnosis and an improvement of the long term management of resistant hypertension. PMID:26935512

  5. Aphid resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Testing and selecting for Russian wheat aphid (RWA) and greenbug resistance in WIT breeding lines continued this year. Several excellent lines with high levels of resistance advanced through the cultivar development process. Single plant selections from six experimental lines were retested to conf...

  6. QTL identification and microphenotype characterisation of the developmentally regulated yellow rust resistance in the UK wheat cultivar Guardian.

    PubMed

    Melichar, J P E; Berry, S; Newell, C; MacCormack, R; Boyd, L A

    2008-08-01

    Yellow rust (causal agent: Puccinia striiformis f.sp. tritici) resistance in the UK wheat cultivar Guardian is developmentally regulated, resistance increasing as the plant matures. Yellow rust resistance was assessed under field conditions on plants after ear emergence to ensure maximum expression of resistance. Three quantitative trait loci (QTL) for yellow rust resistance were identified, being located on chromosomes 1B (QPst.jic-1B), 2D (QPst.jic-2D) and 4B (QPst.jic-4B). The largest resistance effect, QPst.jic-1B located to the same position on the long arm of chromosome 1B as the known durable source of yellow rust resistance, Yr29. Microscopic studies were carried out to determine what effect the resistance in Guardian had on the development of P. striiformis f.sp. tritici. While the adult plant resistance in Guardian did not prevent germinated urediniospores from establishing an effective infection site, the growth of hyphae within flag leaf tissue was significantly inhibited, slowing the development of microcolonies. 3,3-diaminabenzadine (DAB) and trypan blue staining indicated that this inhibition of hyphal growth was not associated with hydrogen peroxide accumulation or extensive plant cell death. PMID:18481042

  7. Resisting HRD's Resistance to Diversity

    ERIC Educational Resources Information Center

    Bierema, Laura L.

    2010-01-01

    Purpose: The purpose of this paper is to empirically illustrate how human resource development (HRD) resists and omits issues of diversity in academic programs, textbooks, and research; analyze the research on HRD and diversity over a ten-year period; discuss HRD's resistance to diversity; and offer some recommendations for a more authentic…

  8. Resistivity analysis

    SciTech Connect

    Bruce, Michael R.; Bruce, Victoria J.; Ring, Rosalinda M.; Cole, Edward Jr. I.; Hawkins, Charles F.; Tangyungong, Paiboon

    2006-06-13

    According to an example embodiment of the present invention a semiconductor die having a resistive electrical connection is analyzed. Heat is directed to the die as the die is undergoing a state-changing operation to cause a failure due to suspect circuitry. The die is monitored, and a circuit path that electrically changes in response to the heat is detected and used to detect that a particular portion therein of the circuit is resistive. In this manner, the detection and localization of a semiconductor die defect that includes a resistive portion of a circuit path is enhanced.

  9. Genetic analysis of leaf rust resistance in six durum wheat genotypes.

    PubMed

    Loladze, Alexander; Kthiri, Dhouha; Pozniak, Curtis; Ammar, Karim

    2014-12-01

    Leaf rust, caused by Puccinia triticina, is one of the main fungal diseases limiting durum wheat production. This study aimed to characterize previously undescribed genes for leaf rust resistance in durum wheat. Six different resistant durum genotypes were crossed to two susceptible International Maize and Wheat Improvement Center (CIMMYT) lines and the resulting F1, F2, and F3 progenies were evaluated for leaf rust reactions in the field and under greenhouse conditions. In addition, allelism tests were conducted. The results of the study indicated that most genotypes carried single effective dominant or recessive seedling resistance genes; the only exception to this was genotype Gaza, which carried one adult plant and one seedling resistance gene. In addition, it was concluded that the resistance genes identified in the current study were neither allelic to LrCamayo or Lr61, nor were they related to Lr3 or Lr14a, the genes that already are either ineffective or are considered to be vulnerable for breeding purposes. A complicated allelic or linkage relationship between the identified genes is discussed. The results of the study will be useful for breeding for durable resistance by creating polygenic complexes. PMID:24906010

  10. Antimicrobial Resistance

    MedlinePlus

    ... and health professionals can play their part; rewarding innovation and development of new treatment options and other ... and industry can help tackle resistance by: fostering innovation and research and development of new vaccines, diagnostics, ...

  11. Antimicrobial Resistance

    MedlinePlus

    ... antibiotic are known as methicillin-resistant S. aureus or MRSA. Antibiotics and other antimicrobial drugs first became widely ... factors for infection are known as community-associated MRSA (CA-MRSA). Recently, several cases overseas and in ...

  12. Lantibiotic resistance.

    PubMed

    Draper, Lorraine A; Cotter, Paul D; Hill, Colin; Ross, R Paul

    2015-06-01

    The dramatic rise in the incidence of antibiotic resistance demands that new therapeutic options will have to be developed. One potentially interesting class of antimicrobials are the modified bacteriocins termed lantibiotics, which are bacterially produced, posttranslationally modified, lanthionine/methyllanthionine-containing peptides. It is interesting that low levels of resistance have been reported for lantibiotics compared with commercial antibiotics. Given that there are very few examples of naturally occurring lantibiotic resistance, attempts have been made to deliberately induce resistance phenotypes in order to investigate this phenomenon. Mechanisms that hinder the action of lantibiotics are often innate systems that react to the presence of any cationic peptides/proteins or ones which result from cell well damage, rather than being lantibiotic specific. Such resistance mechanisms often arise due to altered gene regulation following detection of antimicrobials/cell wall damage by sensory proteins at the membrane. This facilitates alterations to the cell wall or changes in the composition of the membrane. Other general forms of resistance include the formation of spores or biofilms, which are a common mechanistic response to many classes of antimicrobials. In rare cases, bacteria have been shown to possess specific antilantibiotic mechanisms. These are often species specific and include the nisin lytic protein nisinase and the phenomenon of immune mimicry. PMID:25787977

  13. Lantibiotic Resistance

    PubMed Central

    Draper, Lorraine A.; Ross, R. Paul

    2015-01-01

    SUMMARY The dramatic rise in the incidence of antibiotic resistance demands that new therapeutic options will have to be developed. One potentially interesting class of antimicrobials are the modified bacteriocins termed lantibiotics, which are bacterially produced, posttranslationally modified, lanthionine/methyllanthionine-containing peptides. It is interesting that low levels of resistance have been reported for lantibiotics compared with commercial antibiotics. Given that there are very few examples of naturally occurring lantibiotic resistance, attempts have been made to deliberately induce resistance phenotypes in order to investigate this phenomenon. Mechanisms that hinder the action of lantibiotics are often innate systems that react to the presence of any cationic peptides/proteins or ones which result from cell well damage, rather than being lantibiotic specific. Such resistance mechanisms often arise due to altered gene regulation following detection of antimicrobials/cell wall damage by sensory proteins at the membrane. This facilitates alterations to the cell wall or changes in the composition of the membrane. Other general forms of resistance include the formation of spores or biofilms, which are a common mechanistic response to many classes of antimicrobials. In rare cases, bacteria have been shown to possess specific antilantibiotic mechanisms. These are often species specific and include the nisin lytic protein nisinase and the phenomenon of immune mimicry. PMID:25787977

  14. Screening and incorporation of rust resistance from Allium cepa into bunching onion (Allium fistulosum) via alien chromosome addition.

    PubMed

    Wako, Tadayuki; Yamashita, Ken-ichiro; Tsukazaki, Hikaru; Ohara, Takayoshi; Kojima, Akio; Yaguchi, Shigenori; Shimazaki, Satoshi; Midorikawa, Naoko; Sakai, Takako; Yamauchi, Naoki; Shigyo, Masayoshi

    2015-04-01

    Bunching onion (Allium fistulosum L.; 2n = 16), bulb onion (Allium cepa L. Common onion group), and shallot (Allium cepa L. Aggregatum group) cultivars were inoculated with rust fungus, Puccinia allii, isolated from bunching onion. Bulb onions and shallots are highly resistant to rust, suggesting they would serve as useful resources for breeding rust resistant bunching onions. To identify the A. cepa chromosome(s) related to rust resistance, a complete set of eight A. fistulosum - shallot monosomic alien addition lines (MAALs) were inoculated with P. allii. At the seedling stage, FF+1A showed a high level of resistance in controlled-environment experiments, suggesting that the genes related to rust resistance could be located on shallot chromosome 1A. While MAAL, multi-chromosome addition line, and hypoallotriploid adult plants did not exhibit strong resistance to rust. In contrast to the high resistance of shallot, the addition line FF+1A+5A showed reproducibly high levels of rust resistance. PMID:26218854

  15. Nested Association Mapping of Stem Rust Resistance in Wheat Using Genotyping by Sequencing

    PubMed Central

    Rouse, Matthew N.; Tsilo, Toi J.; Macharia, Godwin K.; Bhavani, Sridhar; Jin, Yue; Anderson, James A.

    2016-01-01

    We combined the recently developed genotyping by sequencing (GBS) method with joint mapping (also known as nested association mapping) to dissect and understand the genetic architecture controlling stem rust resistance in wheat (Triticum aestivum). Ten stem rust resistant wheat varieties were crossed to the susceptible line LMPG-6 to generate F6 recombinant inbred lines. The recombinant inbred line populations were phenotyped in Kenya, South Africa, and St. Paul, Minnesota, USA. By joint mapping of the 10 populations, we identified 59 minor and medium-effect QTL (explained phenotypic variance range of 1% – 20%) on 20 chromosomes that contributed towards adult plant resistance to North American Pgt races as well as the highly virulent Ug99 race group. Fifteen of the 59 QTL were detected in multiple environments. No epistatic relationship was detected among the QTL. While these numerous small- to medium-effect QTL are shared among the families, the founder parents were found to have different allelic effects for the QTL. Fourteen QTL identified by joint mapping were also detected in single-population mapping. As these QTL were mapped using SNP markers with known locations on the physical chromosomes, the genomic regions identified with QTL could be explored more in depth to discover candidate genes for stem rust resistance. The use of GBS-derived de novo SNPs in mapping resistance to stem rust shown in this study could be used as a model to conduct similar marker-trait association studies in other plant species. PMID:27186883

  16. Drug Resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Drug resistance refers to both intrinsic and acquired abilities of cells or organisms to become insensitive or refractory to chemotherapeutic intervention. The advent of antibiotics is considered one of the most important medicinal developments in human history, which has led to significantly reduce...

  17. [Resistant hypertension].

    PubMed

    Feldstein, Carlos A

    2008-04-01

    Resistant hypertension, defined as a persistent blood pressure over 140/90 mmHg despite the use of three antihypertensive drugs including a diuretic, is unusual. The diagnosis requires ruling out initially pseudoresistance and a lack of compliance with treatment. Ambulatory blood pressure recording allow the recognition of white coat hypertension. When there is a clinical or laboratory suspicion, secondary causes of hypertension should be discarded. Excessive salt intake, the presence of concomitant diseases such as diabetes mellitus, chronic renal disease, obesity, and psychiatric conditions such as panic attacks, anxiety and depression, should also be sought. The presence of target organ damage requires a more aggressive treatment of hypertension. Recent clinical studies indicate that the administration of aldosterone antagonists as a fourth therapeutic line provides significant additional blood pressure reduction, when added to previous antihypertensive regimens in subjects with resistant hypertension. The possible blood pressure lowering effects of prolonged electrical activation of carotid baroreceptors is under investigation. PMID:18769797

  18. Pre-resistance-welding resistance check

    DOEpatents

    Destefan, Dennis E.; Stompro, David A.

    1991-01-01

    A preweld resistance check for resistance welding machines uses an open circuited measurement to determine the welding machine resistance, a closed circuit measurement to determine the parallel resistance of a workpiece set and the machine, and a calculation to determine the resistance of the workpiece set. Any variation in workpiece set or machine resistance is an indication that the weld may be different from a control weld.

  19. Genetic Architecture of Resistance to Stripe Rust in a Global Winter Wheat Germplasm Collection.

    PubMed

    Bulli, Peter; Zhang, Junli; Chao, Shiaoman; Chen, Xianming; Pumphrey, Michael

    2016-01-01

    Virulence shifts in populations of Puccinia striiformis f. sp. tritici (Pst), the causal pathogen of wheat stripe rust, are a major challenge to resistance breeding. The majority of known resistance genes are already ineffective against current races of Pst, necessitating the identification and introgression of new sources of resistance. Germplasm core collections that reflect the range of genetic and phenotypic diversity of crop species are ideal platforms for examining the genetic architecture of complex traits such as resistance to stripe rust. We report the results of genetic characterization and genome-wide association analysis (GWAS) for resistance to stripe rust in a core subset of 1175 accessions in the National Small Grains Collection (NSGC) winter wheat germplasm collection, based on genotyping with the wheat 9K single nucleotide polymorphism (SNP) iSelect assay and phenotyping of seedling and adult plants under natural disease epidemics in four environments. High correlations among the field data translated into high heritability values within and across locations. Population structure was evident when accessions were grouped by stripe rust reaction. GWAS identified 127 resistance loci that were effective across at least two environments, including 20 with significant genome-wide adjusted P-values. Based on relative map positions of previously reported genes and QTL, five of the QTL with significant genome-wide adjusted P-values in this study represent potentially new loci. This study provides an overview of the diversity of Pst resistance in the NSGC winter wheat germplasm core collection, which can be exploited for diversification of stripe rust resistance in breeding programs. PMID:27226168

  20. Genetic Architecture of Resistance to Stripe Rust in a Global Winter Wheat Germplasm Collection

    PubMed Central

    Bulli, Peter; Zhang, Junli; Chao, Shiaoman; Chen, Xianming; Pumphrey, Michael

    2016-01-01

    Virulence shifts in populations of Puccinia striiformis f. sp. tritici (Pst), the causal pathogen of wheat stripe rust, are a major challenge to resistance breeding. The majority of known resistance genes are already ineffective against current races of Pst, necessitating the identification and introgression of new sources of resistance. Germplasm core collections that reflect the range of genetic and phenotypic diversity of crop species are ideal platforms for examining the genetic architecture of complex traits such as resistance to stripe rust. We report the results of genetic characterization and genome-wide association analysis (GWAS) for resistance to stripe rust in a core subset of 1175 accessions in the National Small Grains Collection (NSGC) winter wheat germplasm collection, based on genotyping with the wheat 9K single nucleotide polymorphism (SNP) iSelect assay and phenotyping of seedling and adult plants under natural disease epidemics in four environments. High correlations among the field data translated into high heritability values within and across locations. Population structure was evident when accessions were grouped by stripe rust reaction. GWAS identified 127 resistance loci that were effective across at least two environments, including 20 with significant genome-wide adjusted P-values. Based on relative map positions of previously reported genes and QTL, five of the QTL with significant genome-wide adjusted P-values in this study represent potentially new loci. This study provides an overview of the diversity of Pst resistance in the NSGC winter wheat germplasm core collection, which can be exploited for diversification of stripe rust resistance in breeding programs. PMID:27226168

  1. Mechanisms of drug resistance: quinolone resistance

    PubMed Central

    Hooper, David C.; Jacoby, George A.

    2015-01-01

    Quinolone antimicrobials are synthetic and widely used in clinical medicine. Resistance emerged with clinical use and became common in some bacterial pathogens. Mechanisms of resistance include two categories of mutation and acquisition of resistance-conferring genes. Resistance mutations in one or both of the two drug target enzymes, DNA gyrase and DNA topoisomerase IV, are commonly in a localized domain of the GyrA and ParE subunits of the respective enzymes and reduce drug binding to the enzyme-DNA complex. Other resistance mutations occur in regulatory genes that control the expression of native efflux pumps localized in the bacterial membrane(s). These pumps have broad substrate profiles that include quinolones as well as other antimicrobials, disinfectants, and dyes. Mutations of both types can accumulate with selection pressure and produce highly resistant strains. Resistance genes acquired on plasmids can confer low-level resistance that promotes the selection of mutational high-level resistance. Plasmid-encoded resistance is due to Qnr proteins that protect the target enzymes from quinolone action, one mutant aminoglycoside-modifying enzyme that also modifies certain quinolones, and mobile efflux pumps. Plasmids with these mechanisms often encode additional antimicrobial resistances and can transfer multidrug resistance that includes quinolones. Thus, the bacterial quinolone resistance armamentarium is large. PMID:26190223

  2. Mechanisms of drug resistance: quinolone resistance.

    PubMed

    Hooper, David C; Jacoby, George A

    2015-09-01

    Quinolone antimicrobials are synthetic and widely used in clinical medicine. Resistance emerged with clinical use and became common in some bacterial pathogens. Mechanisms of resistance include two categories of mutation and acquisition of resistance-conferring genes. Resistance mutations in one or both of the two drug target enzymes, DNA gyrase and DNA topoisomerase IV, are commonly in a localized domain of the GyrA and ParE subunits of the respective enzymes and reduce drug binding to the enzyme-DNA complex. Other resistance mutations occur in regulatory genes that control the expression of native efflux pumps localized in the bacterial membrane(s). These pumps have broad substrate profiles that include quinolones as well as other antimicrobials, disinfectants, and dyes. Mutations of both types can accumulate with selection pressure and produce highly resistant strains. Resistance genes acquired on plasmids can confer low-level resistance that promotes the selection of mutational high-level resistance. Plasmid-encoded resistance is due to Qnr proteins that protect the target enzymes from quinolone action, one mutant aminoglycoside-modifying enzyme that also modifies certain quinolones, and mobile efflux pumps. Plasmids with these mechanisms often encode additional antimicrobial resistances and can transfer multidrug resistance that includes quinolones. Thus, the bacterial quinolone resistance armamentarium is large. PMID:26190223

  3. Inheritance of prehaustorial resistance to Puccinia graminis f. sp. avenae in barley (Hordeum vulgare L.).

    PubMed

    Dracatos, Peter M; Ayliffe, Michael; Khatkar, Mehar S; Fetch, Tom; Singh, Davinder; Park, Robert F

    2014-11-01

    Rust pathogens within the genus Puccinia cause some of the most economically significant diseases of crops. Different formae speciales of P. graminis have co-evolved to mainly infect specific grass hosts; however, some genotypes of other closely related cereals can also be infected. This study investigated the inheritance of resistance to three diverse pathotypes of the oat stem rust pathogen (P. graminis f. sp. avenae) in the 'Yerong' ✕ 'Franklin' (Y/F) barley doubled haploid (DH) population, a host with which it is not normally associated. Both parents, 'Yerong' and 'Franklin', were immune to all P. graminis f. sp. avenae pathotypes; however. there was transgressive segregation within the Y/F population, in which infection types (IT) ranged from complete immunity to mesothetic susceptibility, suggesting the presence of heritable resistance. Both QTL and marker-trait association (MTA) analysis was performed on the Y/F population to map resistance loci in response to P. graminis f. sp. avenae. QTL on chromosome 1H ('Yerong' Rpga1 and Rpga2) were identified using all forms of analysis, while QTL detected on 5H ('Franklin' Rpga3 and Rpga4) and 7H (Rpga5) were only detected using MTA or composite interval mapping-single marker regression analysis respectively. Rpga1 to Rpga5 were effective in response to all P. graminis f. sp. avenae pathotypes used in this study, suggesting resistance is not pathotype specific. Rpga1 co-located to previously mapped QTL in the Y/F population for adult plant resistance to the barley leaf scald pathogen (Rhynchosporium secalis) on chromosome 1H. Histological evidence suggests that the resistance observed within parental and immune DH lines in the population was prehaustorial and caused by callose deposition within the walls of the mesophyll cells, preventing hyphal penetration. PMID:25025780

  4. HIV Genotypic Resistance Testing

    MedlinePlus

    ... be limited. Home Visit Global Sites Search Help? HIV Antiretroviral Drug Resistance Testing, Genotypic Share this page: Was this page helpful? Also known as: Anti-retroviral Drug Resistance Testing; ARV Resistance Testing Formal name: ...

  5. The expression and genetics of resistance to stripe (yellow) rust in three European and four New Zealand wheat cultivars.

    PubMed

    Pathan, Amin K; Park, Robert F; Wellings, Colin R; Bariana, Harbans S

    2007-01-01

    Adult plant resistance (APR) to stripe rust in three European (Pegaso, Victo and Aztec) and four New Zealand cultivars (Weka, Kopara, Kokart and Takahe) was characterised using hybrid analysis and tests of allelism. In agreement with earlier work, the APR in most of these cultivars appeared to be controlled by two or more genes with additive effects. It was suggested that heavy selection pressure should be avoided in early generations in breeding programs utilising APR, because lines in which APR genes are heterozygous may display lower levels of resistance due to the incompletely dominant and interactive nature of many APRs. Such lines are capable of generating more resistant progenies following selfing. It was also demonstrated that it is possible to misclassify F2 plants as susceptible if APR genes are in a heterozygous condition, especially in the case of gene(s) conferring intermediate levels of resistance. The presence of a common APR gene in Kopara and Takahe, and perhaps Weka, was suggested because all shared a common parent in their pedigree and no susceptible plants were observed in F2 populations derived from intercrossing them. The difficulties inherent in conducting genetic studies on APRs and the need for large population sizes for such studies were emphasised. PMID:17666772

  6. Genome-wide association study for crown rust (Puccinia coronata f. sp. avenae) and powdery mildew (Blumeria graminis f. sp. avenae) resistance in an oat (Avena sativa) collection of commercial varieties and landraces.

    PubMed

    Montilla-Bascón, Gracia; Rispail, Nicolas; Sánchez-Martín, Javier; Rubiales, Diego; Mur, Luis A J; Langdon, Tim; Howarth, Catherine J; Prats, Elena

    2015-01-01

    Diseases caused by crown rust (Puccinia coronata f. sp. avenae) and powdery mildew (Blumeria graminis f. sp. avenae) are among the most important constraints for the oat crop. Breeding for resistance is one of the most effective, economical, and environmentally friendly means to control these diseases. The purpose of this work was to identify elite alleles for rust and powdery mildew resistance in oat by association mapping to aid selection of resistant plants. To this aim, 177 oat accessions including white and red oat cultivars and landraces were evaluated for disease resistance and further genotyped with 31 simple sequence repeat and 15,000 Diversity Arrays Technology (DArT) markers to reveal association with disease resistance traits. After data curation, 1712 polymorphic markers were considered for association analysis. Principal component analysis and a Bayesian clustering approach were applied to infer population structure. Five different general and mixed linear models accounting for population structure and/or kinship corrections and two different statistical tests were carried out to reduce false positive. Five markers, two of them highly significant in all models tested were associated with rust resistance. No strong association between any marker and powdery mildew resistance at the seedling stage was identified. However, one DArT sequence, oPt-5014, was strongly associated with powdery mildew resistance in adult plants. Overall, the markers showing the strongest association in this study provide ideal candidates for further studies and future inclusion in strategies of marker-assisted selection. PMID:25798140

  7. A change in temperature modulates defence to yellow (stripe) rust in wheat line UC1041 independently of resistance gene Yr36

    PubMed Central

    2014-01-01

    Background Rust diseases are of major importance in wheat production worldwide. With the constant evolution of new rust strains and their adaptation to higher temperatures, consistent and durable disease resistance is a key challenge. Environmental conditions affect resistance gene performance, but the basis for this is poorly understood. Results Here we show that a change in day temperature affects wheat resistance to Puccinia striiformis f. sp tritici (Pst), the causal agent of yellow (or stripe) rust. Using adult plants of near-isogenic lines UC1041 +/- Yr36, there was no significant difference between Pst percentage uredia coverage in plants grown at day temperatures of 18°C or 25°C in adult UC1041 + Yr36 plants. However, when plants were transferred to the lower day temperature at the time of Pst inoculation, infection increased up to two fold. Interestingly, this response was independent of Yr36, which has previously been reported as a temperature-responsive resistance gene as Pst development in adult UC1041 -Yr36 plants was similarly affected by the plants experiencing a temperature reduction. In addition, UC1041 -Yr36 plants grown at the lower temperature then transferred to the higher temperature were effectively resistant and a temperature change in either direction was shown to affect Pst development up to 8 days prior to inoculation. Results for seedlings were similar, but more variable compared to adult plants. Enhanced resistance to Pst was observed in seedlings of UC1041 and the cultivar Shamrock when transferred to the higher temperature. Resistance was not affected in seedlings of cultivar Solstice by a temperature change in either direction. Conclusions Yr36 is effective at 18°C, refining the lower range of temperature at which resistance against Pst is conferred compared to previous studies. Results reveal previously uncharacterised defence temperature sensitivity in the UC1041 background which is caused by a change in temperature and

  8. Facts about Antibiotic Resistance

    MedlinePlus

    ... Trends and Cost Español: Datos breves Facts about Antibiotic Resistance Antibiotic resistance has been called one of the world’s most ... antibiotic use is a key strategy to control antibiotic resistance. Antibiotic resistance in children is of particular concern ...

  9. Anthelmintic resistance: markers for resistance, or susceptibility?

    PubMed Central

    BEECH, R. N.; SKUCE, P.; BARTLEY, D. J.; MARTIN, R. J.; PRICHARD, R. K.; GILLEARD, J. S.

    2010-01-01

    SUMMARY The Consortium for Anthelmintic Resistance and Susceptibility (CARS) brings together researchers worldwide, with a focus of advancing knowledge of resistance and providing information on detection methods and treatment strategies. Advances in this field suggest mechanisms and features of resistance that are shared among different classes of anthelmintic. Benzimidazole resistance is characterized by specific amino acid substitutions in beta-tubulin. If present, these substitutions increase in frequency upon drug treatment and lead to treatment failure. In the laboratory, sequence substitutions in ion-channels can contribute to macrocyclic lactone resistance, but there is little evidence that they are significant in the field. Changes in gene expression are associated with resistance to several different classes of anthelmintic. Increased P-glycoprotein expression may prevent drug access to its site of action. Decreased expression of ion-channel subunits and the loss of specific receptors may remove the drug target. Tools for the identification and genetic analysis of parasitic nematodes and a new online database will help to coordinate research efforts in this area. Resistance may result from a loss of sensitivity as well as the appearance of resistance. A focus on the presence of anthelmintic susceptibility may be as important as the detection of resistance. PMID:20825689

  10. Resistance Factor-Mediated Spectinomycin Resistance

    PubMed Central

    Smith, David H.; Janjigian, J. A.; Prescott, Naomi; Anderson, Porter W.

    1970-01-01

    Of 100 natural isolates of drug-resistant enteric bacteria, 51 were resistant to spectinomycin (Spc) and 46 contained transferable R factors mediating Spc resistance. All SpcR R factors mediated streptomycin and bluensomycin resistance and were fi+ type. Extracts of R-SpcR strains adenylated Spc, dihydrospectinomycin, actinamine, streptomycin, and bluensomycin in vitro in the presence of adenosine triphosphate and Mg++. Results of genetic and biochemical studies support the hypothesis that these reactions are mediated by a single enzyme. PMID:16557684

  11. Multidrug Resistance in Bacteria

    PubMed Central

    Nikaido, Hiroshi

    2010-01-01

    Large amounts of antibiotics used for human therapy, as well as for farm animals and even for fish in aquaculture, resulted in the selection of pathogenic bacteria resistant to multiple drugs. Multidrug resistance in bacteria may be generated by one of two mechanisms. First, these bacteria may accumulate multiple genes, each coding for resistance to a single drug, within a single cell. This accumulation occurs typically on resistance (R) plasmids. Second, multidrug resistance may also occur by the increased expression of genes that code for multidrug efflux pumps, extruding a wide range of drugs. This review discusses our current knowledge on the molecular mechanisms involved in both types of resistance. PMID:19231985

  12. A Genome-Wide Association Study of Resistance to Stripe Rust (Puccinia striiformis f. sp. tritici) in a Worldwide Collection of Hexaploid Spring Wheat (Triticum aestivum L.)

    PubMed Central

    Maccaferri, Marco; Zhang, Junli; Bulli, Peter; Abate, Zewdie; Chao, Shiaoman; Cantu, Dario; Bossolini, Eligio; Chen, Xianming; Pumphrey, Michael; Dubcovsky, Jorge

    2015-01-01

    New races of Puccinia striiformis f. sp. tritici (Pst), the causal pathogen of wheat stripe rust, show high virulence to previously deployed resistance genes and are responsible for large yield losses worldwide. To identify new sources of resistance we performed a genome-wide association study (GWAS) using a worldwide collection of 1000 spring wheat accessions. Adult plants were evaluated under field conditions in six environments in the western United States, and seedlings were tested with four Pst races. A single-nucleotide polymorphism (SNP) Infinium 9K-assay provided 4585 SNPs suitable for GWAS. High correlations among environments and high heritabilities were observed for stripe rust infection type and severity. Greater levels of Pst resistance were observed in a subpopulation from Southern Asia than in other groups. GWAS identified 97 loci that were significant for at least three environments, including 10 with an experiment-wise adjusted Bonferroni probability < 0.10. These 10 quantitative trait loci (QTL) explained 15% of the phenotypic variation in infection type, a percentage that increased to 45% when all QTL were considered. Three of these 10 QTL were mapped far from previously identified Pst resistance genes and QTL, and likely represent new resistance loci. The other seven QTL mapped close to known resistance genes and allelism tests will be required to test their relationships. In summary, this study provides an integrated view of stripe rust resistance resources in spring wheat and identifies new resistance loci that will be useful to diversify the current set of resistance genes deployed to control this devastating disease. PMID:25609748

  13. A genome-wide association study of resistance to stripe rust (Puccinia striiformis f. sp. tritici) in a worldwide collection of hexaploid spring wheat (Triticum aestivum L.).

    PubMed

    Maccaferri, Marco; Zhang, Junli; Bulli, Peter; Abate, Zewdie; Chao, Shiaoman; Cantu, Dario; Bossolini, Eligio; Chen, Xianming; Pumphrey, Michael; Dubcovsky, Jorge

    2015-03-01

    New races of Puccinia striiformis f. sp. tritici (Pst), the causal pathogen of wheat stripe rust, show high virulence to previously deployed resistance genes and are responsible for large yield losses worldwide. To identify new sources of resistance we performed a genome-wide association study (GWAS) using a worldwide collection of 1000 spring wheat accessions. Adult plants were evaluated under field conditions in six environments in the western United States, and seedlings were tested with four Pst races. A single-nucleotide polymorphism (SNP) Infinium 9K-assay provided 4585 SNPs suitable for GWAS. High correlations among environments and high heritabilities were observed for stripe rust infection type and severity. Greater levels of Pst resistance were observed in a subpopulation from Southern Asia than in other groups. GWAS identified 97 loci that were significant for at least three environments, including 10 with an experiment-wise adjusted Bonferroni probability < 0.10. These 10 quantitative trait loci (QTL) explained 15% of the phenotypic variation in infection type, a percentage that increased to 45% when all QTL were considered. Three of these 10 QTL were mapped far from previously identified Pst resistance genes and QTL, and likely represent new resistance loci. The other seven QTL mapped close to known resistance genes and allelism tests will be required to test their relationships. In summary, this study provides an integrated view of stripe rust resistance resources in spring wheat and identifies new resistance loci that will be useful to diversify the current set of resistance genes deployed to control this devastating disease. PMID:25609748

  14. Stem Rust Resistance in a Geographically Diverse Collection of Spring Wheat Lines Collected from Across Africa.

    PubMed

    Prins, Renée; Dreisigacker, Susanne; Pretorius, Zakkie; van Schalkwyk, Hester; Wessels, Elsabet; Smit, Corneli; Bender, Cornel; Singh, Davinder; Boyd, Lesley A

    2016-01-01

    Following the emergence of the Ug99 lineage of Puccinia graminis f. sp. tritici (Pgt) a collective international effort has been undertaken to identify new sources of wheat stem rust resistance effective against these races. Analyses were undertaken in a collection of wheat genotypes gathered from across Africa to identify stem rust resistance effective against the Pgt races found in Eastern and Southern Africa. The African wheat collection consisted of historic genotypes collected in Kenya, South Africa, Ethiopia, Sudan, Zambia, Morocco, and Tunisia, and current South African breeding lines. Both Bayesian cluster and principal coordinate analyses placed the wheat lines from Sudan in a distinct group, but indicated a degree of genetic relatedness among the other wheat lines despite originating from countries across Africa. Seedling screens with Pgt race PTKST, pedigree information and marker haplotype analysis confirmed the presence of Sr2, Sr36, Sr24, Sr31, and Lr34/Yr18/Sr57 in a number of the lines. A genome-wide association study (GWAS) undertaken with Diversiry Arrays Technology (DArT) and stem rust (Sr) gene associated markers and Stem Area Infected (SAI) and Reaction Type (RT) field phenotypes, collected from trials carried out across two seasons in Kenya in 2009 and in South Africa in 2011, identified 29 marker-trait associations (MTA). Three MTA were in common between SAI and RT, with the biggest effect MTA being found on chromosome 6AS. Two wheat lines, W1406 and W6979 that exhibited high levels of adult plant stem rust resistance were selected to generate bi-parental mapping populations. Only the MTA on chromosomes 6AS and 3BS, and the locus Lr34/Yr18/Sr57 were confirmed following QTL mapping. Additional stem rust resistance QTL, not detected by the GWAS, were found on chromosomes 2BS, 2DL, 3DL, and 4D. PMID:27462322

  15. Stem Rust Resistance in a Geographically Diverse Collection of Spring Wheat Lines Collected from Across Africa

    PubMed Central

    Prins, Renée; Dreisigacker, Susanne; Pretorius, Zakkie; van Schalkwyk, Hester; Wessels, Elsabet; Smit, Corneli; Bender, Cornel; Singh, Davinder; Boyd, Lesley A.

    2016-01-01

    Following the emergence of the Ug99 lineage of Puccinia graminis f. sp. tritici (Pgt) a collective international effort has been undertaken to identify new sources of wheat stem rust resistance effective against these races. Analyses were undertaken in a collection of wheat genotypes gathered from across Africa to identify stem rust resistance effective against the Pgt races found in Eastern and Southern Africa. The African wheat collection consisted of historic genotypes collected in Kenya, South Africa, Ethiopia, Sudan, Zambia, Morocco, and Tunisia, and current South African breeding lines. Both Bayesian cluster and principal coordinate analyses placed the wheat lines from Sudan in a distinct group, but indicated a degree of genetic relatedness among the other wheat lines despite originating from countries across Africa. Seedling screens with Pgt race PTKST, pedigree information and marker haplotype analysis confirmed the presence of Sr2, Sr36, Sr24, Sr31, and Lr34/Yr18/Sr57 in a number of the lines. A genome-wide association study (GWAS) undertaken with Diversiry Arrays Technology (DArT) and stem rust (Sr) gene associated markers and Stem Area Infected (SAI) and Reaction Type (RT) field phenotypes, collected from trials carried out across two seasons in Kenya in 2009 and in South Africa in 2011, identified 29 marker-trait associations (MTA). Three MTA were in common between SAI and RT, with the biggest effect MTA being found on chromosome 6AS. Two wheat lines, W1406 and W6979 that exhibited high levels of adult plant stem rust resistance were selected to generate bi-parental mapping populations. Only the MTA on chromosomes 6AS and 3BS, and the locus Lr34/Yr18/Sr57 were confirmed following QTL mapping. Additional stem rust resistance QTL, not detected by the GWAS, were found on chromosomes 2BS, 2DL, 3DL, and 4D. PMID:27462322

  16. Flame-resistant textiles

    NASA Technical Reports Server (NTRS)

    Fogg, L. C.; Stringham, R. S.; Toy, M. S.

    1980-01-01

    Flame resistance treatment for acid resistant polyamide fibers involving photoaddition of fluorocarbons to surface has been scaled up to treat 10 yards of commercial width (41 in.) fabric. Process may be applicable to other low cost polyamides, polyesters, and textiles.

  17. Antibiotics and Resistance: Glossary

    MedlinePlus

    ... induced by natural or human activity on the ecology and living organisms. Ecology The study of the relationships and interactions between ... antibiotics The Cost of Resistance Science of Resistance Ecology Antibiotics in Agriculture Antibacterial Agents Glossary References Web ...

  18. Power to Resist

    ERIC Educational Resources Information Center

    Crossland, Janice

    1975-01-01

    Transferrable drug resistance has been observed in bacteria for over ten years. Concern now is that livestock that have been fed with grain supplemented with antibiotics for growth stimulation will infect humans with potentially dangerous resistant bacteria. (MA)

  19. Oxidation-resistant cermet

    NASA Technical Reports Server (NTRS)

    Phillips, W. M.

    1977-01-01

    Chromium metal alloys and chromium oxide ceramic are combined to produce cermets with oxidation-resistant properties. Application of cermets includes use in hot corrosive environments requiring strong resistive materials.

  20. Animation of Antimicrobial Resistance

    MedlinePlus

    ... major obstacles to understanding the issue of antimicrobial resistance is that the subject material appears abstract and is complex. This video was designed to make the concept of antimicrobial resistance more real and understandable to veterinarians, livestock producers, ...

  1. Identification and mapping of leaf, stem and stripe rust resistance quantitative trait loci and their interactions in durum wheat.

    PubMed

    Singh, A; Pandey, M P; Singh, A K; Knox, R E; Ammar, K; Clarke, J M; Clarke, F R; Singh, R P; Pozniak, C J; Depauw, R M; McCallum, B D; Cuthbert, R D; Randhawa, H S; Fetch, T G

    2013-02-01

    Leaf rust (Puccinia triticina Eriks.), stripe rust (Puccinia striiformis f. tritici Eriks.) and stem rust (Puccinia graminis f. sp. tritici) cause major production losses in durum wheat (Triticum turgidum L. var. durum). The objective of this research was to identify and map leaf, stripe and stem rust resistance loci from the French cultivar Sachem and Canadian cultivar Strongfield. A doubled haploid population from Sachem/Strongfield and parents were phenotyped for seedling reaction to leaf rust races BBG/BN and BBG/BP and adult plant response was determined in three field rust nurseries near El Batan, Obregon and Toluca, Mexico. Stripe rust response was recorded in 2009 and 2011 nurseries near Toluca and near Njoro, Kenya in 2010. Response to stem rust was recorded in field nurseries near Njoro, Kenya, in 2010 and 2011. Sachem was resistant to leaf, stripe and stem rust. A major leaf rust quantitative trait locus (QTL) was identified on chromosome 7B at Xgwm146 in Sachem. In the same region on 7B, a stripe rust QTL was identified in Strongfield. Leaf and stripe rust QTL around DArT marker wPt3451 were identified on chromosome 1B. On chromosome 2B, a significant leaf rust QTL was detected conferred by Strongfield, and at the same QTL, a Yr gene derived from Sachem conferred resistance. Significant stem rust resistance QTL were detected on chromosome 4B. Consistent interactions among loci for resistance to each rust type across nurseries were detected, especially for leaf rust QTL on 7B. Sachem and Strongfield offer useful sources of rust resistance genes for durum rust breeding. PMID:23396999

  2. Resisting Mind Control.

    ERIC Educational Resources Information Center

    Anderson, Susan M.; Zimbardo, Philip G.

    1980-01-01

    Provides conceptual analyses of mind control techniques along with practical advice on how to resist these techniques. The authors stress that effective mind control stems more from everyday social relations than from exotic technological gimmicks. Suggestions are given for resisting persuasion, resisting systems, and challenging the system.…

  3. Grafting for disease resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The primary purpose of grafting vegetables worldwide has been to provide resistance to soil-borne diseases. The potential loss of methyl bromide as a soil fumigant combined with pathogen resistance to commonly used pesticides will make resistance to soil-borne pathogens even more important in the fu...

  4. Radiation coloration resistant glass

    DOEpatents

    Tomozawa, Minoru; Watson, E. Bruce; Acocella, John

    1986-01-01

    A radiation coloration resistant glass is disclosed which is used in a radiation environment sufficient to cause coloration in most forms of glass. The coloration resistant glass includes higher proportions by weight of water and has been found to be extremely resistant to color change when exposed to such radiation levels. The coloration resistant glass is free of cerium oxide and has more than about 0.5% by weight water content. Even when exposed to gamma radiation of more than 10.sup.7 rad, the coloration resistant glass does not lose transparency.

  5. Radiation coloration resistant glass

    DOEpatents

    Tomozawa, M.; Watson, E.B.; Acocella, J.

    1986-11-04

    A radiation coloration resistant glass is disclosed which is used in a radiation environment sufficient to cause coloration in most forms of glass. The coloration resistant glass includes higher proportions by weight of water and has been found to be extremely resistant to color change when exposed to such radiation levels. The coloration resistant glass is free of cerium oxide and has more than about 0.5% by weight water content. Even when exposed to gamma radiation of more than 10[sup 7] rad, the coloration resistant glass does not lose transparency. 3 figs.

  6. A trade off between mlo resistance to powdery mildew and increased susceptibility of barley to a newly important disease, Ramularia leaf spot

    PubMed Central

    McGrann, Graham R. D.; Brown, James K. M.

    2014-01-01

    Ramularia leaf spot (RLS), caused by the fungus Ramularia collo-cygni, is a serious, recently emerged disease of barley in Europe and other temperate regions. This study investigated the trade off between strong resistance to powdery mildew conferred by mlo mutant alleles and increased susceptibility to RLS. In field trials and seedling tests, the presence of mlo alleles increased severity of RLS. Genetic analysis of a doubled-haploid population identified one quantitative trait locus for susceptibility to RLS, colocalizing with the mlo-11 allele for mildew resistance. The effect of mlo-11 on RLS severity was environmentally sensitive. Analysis of near-isogenic lines of different mlo mutations in various genetic backgrounds confirmed that mlo alleles increased RLS severity in seedlings and adult plants. For mlo resistance to mildew to be fully effective, the genes ROR1 and ROR2 are required. RLS symptoms were significantly reduced on mlo-5 ror double mutants but fungal DNA levels remained as high as in mlo-5 single mutants, implying that ror alleles modify the transition of the fungus from endophytism to necrotrophy. These results indicate that the widespread use of mlo resistance to control mildew may have inadvertently stimulated the emergence of RLS as a major disease of barley. PMID:24399175

  7. [Rodenticide resistance and consequences].

    PubMed

    Esther, A; Endepols, S; Freise, J; Klemann, N; Runge, M; Pelz, H-J

    2014-05-01

    Resistance to anticoagulant rodenticides, such as warfarin was first described in 1958. Polymorphisms in the vitamin K epoxide reductase complex subunit 1 (VKORC1) gene and respective substitutions of amino acids in the VKOR enzyme are the major cause for rodenticide resistance. Resistant Norway rats in Germany are characterized by the Tyr139Cys genotype, which is spread throughout the northwest of the country. Resistant house mice with the VKOR variants Tyr139Cys, Leu128Ser and Arg12Trp/Ala26Ser/Ala48Thr/Arg61Leu (spretus type) are distributed over a number of locations in Germany. Resistance can reduce management attempts with consequences for stored product protection, hygiene and animal health. Anticoagulants of the first generation (warfarin, chlorophacinone, coumatetralyl) as well as bromadiolone and difenacoum are not an option for the control of resistant Norway rats. The same applies for house mice whereby the tolerance to compounds can be different between local incidences. Due to the higher toxicity and tendency to persist, the most potent anticoagulant rodenticides brodifacoum, flocoumafen and difethialone should be applied but only where resistance is known. In other cases less toxic anticoagulants should be preferred for rodent management in order to mitigate environmental risks. Resistance effects of further VKOR polymorphisms and their combinations, the spread of resistant rats and conditions supporting and reducing resistance should be investigated in order to improve resistance management strategies. PMID:24781908

  8. Genetics of metabolic resistance.

    PubMed

    Richter, Otto; Langemann, Dirk; Beffa, Roland

    2016-09-01

    Herbicide resistance has become a major issue for many weeds. Metabolic resistance refers to the biochemical processes within organisms that degrade herbicides to less toxic compounds, resulting in a shift of the dose response curve. This type of resistance involves polygenic inheritance. A model is presented linking the biochemical pathway of amino acid synthesis and the detoxifying pathway of an inhibitor of the key enzyme ALS. From this model, resistance factors for each biotype are derived, which are then applied to a polygenic population genetic model for an annual weed plant. Polygenic inheritance is described by a new approach based on tensor products of heredity matrices. Important results from the model are that low dose regimes favour fast emergence of resistant biotypes and that the emergence of resistant biotypes occurs as abrupt outbreaks. The model is used to evaluate strategies for the management of metabolic resistance. PMID:27424952

  9. Inheritance and Molecular Mapping of an All-Stage Stripe Rust Resistance Gene Derived from the Chinese Common Wheat Landrace "Yilongtuomai".

    PubMed

    Wu, Xue-Lian; Wang, Jian-Wei; Cheng, Yu-Kun; Ye, Xue-Ling; Li, Wei; Pu, Zhi-En; Jiang, Qian-Tao; Wei, Yu-Ming; Deng, Mei; Zheng, You-Liang; Chen, Guo-Yue

    2016-09-01

    Yellow or stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is a devastating foliar disease that affects common wheat (Triticum aestivum L.) around the world. In China, common wheat landraces are potential sources of disease and abiotic stress resistance genes for wheat improvement. Yilongtuomai (YL), a wheat landrace from Yilong County, Sichuan Province, shows high levels of resistance against most Chinese Pst races. In this study, the resistance of YL to stripe rust disease was examined in detail. Parent strains, YL and Taichung 29, a variety susceptible to Pst race CYR32, and their F1, F2, and F2:3 offspring, were inoculated with CYR32 during the seedling stage in the field or adult-plant stage in the greenhouse. Results indicated that resistance to CYR32 in YL is conferred by a single dominant gene, designated YrYL The segregating F2 population (352 plants), was analyzed in terms of its resistance locus using simple sequence repeats (SSRs), resistance gene analog polymorphisms (RGAPs), and sequence-related amplified polymorphism (SRAP). A linkage group of 6 SSRs, 2 RGAPs, and 1 SRAP was constructed for the YrYL gene. Using the identified SSRs associated with physical mapping of RGAP using Chinese Spring nullisomic-tetrasomic stocks, the YrYL gene was localized to the short arm of chromosome 7D. The gene was flanked by 1 SSR marker, Xbarc92, and 1 RGAP marker, CLRRfor/Ptokin4, at genetic distances of 5.35 and 9.86 cM, respectively. The YrYL gene was compared to other stripe rust resistance genes reported on chromosome 7D by evaluating its reaction patterns to CYR32 and its pedigree relationship. Our results suggest that the YrYL gene is a new stripe rust resistance gene. PMID:27208148

  10. EPA RESISTANCE MONITORING RESEARCH (NCR)

    EPA Science Inventory

    The 2006 resistance management research program was organized around three components: development of resistance monitoring program for Bt corn using remote sensing, standardization of resistance assays, and testing of resistance management models. Each area of research has shown...

  11. Yr45, a new wheat gene for stripe rust resistance on the long arm of chromosome 3D.

    PubMed

    Li, Q; Chen, X M; Wang, M N; Jing, J X

    2011-01-01

    Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most destructive diseases of wheat worldwide. Growing resistant cultivars is the most effective approach to control the disease, but only a few genes confer effective all-stage resistance against the current populations of the pathogen worldwide. It is urgent to identify new genes for diversifying sources of resistance genes and for pyramiding genes for different types of resistance in order to achieve high levels of durable resistance for sustainable control of stripe rust. The common spring wheat genotype 'PI 181434', originally from Afghanistan, was resistant in all greenhouse and field tests in our previous studies. To identify the resistance gene(s) PI 181434 was crossed with susceptible genotype 'Avocet Susceptible'. Adult plants of 103 F(2) progeny were tested in the field under the natural infection of P. striiformis f. sp. tritici. Seedlings of the parents, F(2) and F(3) were tested with races PST-100 and PST-127 of the pathogen under controlled greenhouse conditions. The genetic study showed that PI 181434 has a single dominant gene conferring all-stage resistance. Resistance gene analog polymorphism (RGAP) and simple sequence repeat (SSR) techniques were used to identify molecular markers linked to the gene. A linkage map of 8 RGAP and 2 SSR markers was constructed for the gene using data from the 103 F(2) plants and their derived F(3) lines tested in the greenhouse. Amplification of the complete set of nulli-tetrasomic lines and selected ditelosomic lines of Chinese Spring with an RGAP marker and the two SSR markers mapped the gene on the long arm of chromosome 3D. Because it is the first gene for stripe rust resistance mapped on chromosome 3DL and different from all previously named Yr genes, the gene in PI 181434 was designated Yr45. Polymorphism rates of the two closest flanking markers, Xwgp115 and Xwgp118, in 45 wheat genotypes were 73.3 and 82.2%, respectively. Single

  12. Genetic resistance to flaviviruses.

    PubMed

    Brinton, Margo A; Perelygin, Andrey A

    2003-01-01

    Resistance to flavivirus-induced disease in mice was first discovered in the 1920s and was subsequently shown to be controlled by the resistant allele of a single dominant autosomal gene. While the majority of current laboratory mouse stains have a homozygous-susceptible phenotype, the resistant allele has been found to segregate in wild mouse populations in many different parts of the world. Resistance is flavivirus specific and extends to both mosquito- and tick-borne flaviviruses. Resistant animals are infected productively by flaviviruses but produce lower virus titers, especially in their brains, as compared to susceptible mice. Decreased virus production is observed in resistant animals even during a lethal infection and the times of disease onset and death are also delayed as compared to susceptible mice. An intact immune response is required to clear flaviviruses from resistant mice. The resistant phenotype is expressed constitutively and does not require interferon induction. The Flv gene was discovered using a positional cloning approach and identified as Oas1b. Susceptible mice produce a truncated Oas1b protein. A C820T transition in the fourth exon of the gene introduced a premature stop codon and was found in all susceptible mouse strains tested. Possible mechanisms by which the product of the resistant allele could confer the resistant phenotype are discussed. PMID:14689691

  13. Drug Resistance in Leishmaniasis

    PubMed Central

    Chakravarty, Jaya; Sundar, Shyam

    2010-01-01

    The treatment options of leishmaniasis are limited and far from satisfactory. For more than 60 years, treatment of leishmaniasis has centered around pentavalent antimonials (Sbv). Widespread misuse has led to the emergence of Sbv resistance in the hyperendemic areas of North Bihar. Other antileishmanials could also face the same fate, especially in the anthroponotic cycle. The HIV/ visceral leishmaniasis (VL) coinfected patients are another potential source for the emergence of drug resistance. At present no molecular markers of resistance are available and the only reliable method for monitoring resistance of isolates is the technically demanding in vitro amastigote-macrophage model. As the armametrium of drugs for leishmaniasis is limited, it is important that effective monitoring of drug use and response should be done to prevent the spread of resistance. Regimens of simultaneous or sequential combinations should be seriously considered to limit the emergence of resistance. PMID:20606973

  14. Inflammation and Insulin Resistance

    PubMed Central

    de Luca, Carl; Olefsky, Jerrold M.

    2008-01-01

    Obesity-induced chronic inflammation is a key component in the pathogenesis of insulin resistance and the Metabolic syndrome. In this review, we focus on the interconnection between obesity, inflammation and insulin resistance. Pro-inflammatory cytokines can cause insulin resistance in adipose tissue, skeletal muscle and liver by inhibiting insulin signal transduction. The sources of cytokines in insulin resistant states are the insulin target tissue themselves, primarily fat and liver, but to a larger extent the activated tissue resident macrophages. While the initiating factors of this inflammatory response remain to be fully determined, chronic inflammation in these tissues could cause localized insulin resistance via autocrine/paracrine cytokine signaling and systemic insulin resistance via endocrine cytokine signaling all of which contribute to the abnormal metabolic state. PMID:18053812

  15. Vancomycin-Resistant Enterococci

    PubMed Central

    Cetinkaya, Yesim; Falk, Pamela; Mayhall, C. Glen

    2000-01-01

    After they were first identified in the mid-1980s, vancomycin-resistant enterococci (VRE) spread rapidly and became a major problem in many institutions both in Europe and the United States. Since VRE have intrinsic resistance to most of the commonly used antibiotics and the ability to acquire resistance to most of the current available antibiotics, either by mutation or by receipt of foreign genetic material, they have a selective advantage over other microorganisms in the intestinal flora and pose a major therapeutic challenge. The possibility of transfer of vancomycin resistance genes to other gram-positive organisms raises significant concerns about the emergence of vancomycin-resistant Staphylococcus aureus. We review VRE, including their history, mechanisms of resistance, epidemiology, control measures, and treatment. PMID:11023964

  16. Modulation of phosphorylation of tocopherol and phosphatidylinositol by hTAP1/SEC14L2-mediated lipid exchange

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The vitamin E derivative, alpha-tocopheryl phosphate (aTP), is detectable in cultured cells, plasma and tissues in small amounts, suggesting the existence of enzyme(s) with a-tocopherol (aT) kinase activity. Here, we characterize the production of aTP from aT and [g-32P]-ATP in primary human coronar...

  17. Bacterial resistance to uncouplers.

    PubMed

    Lewis, K; Naroditskaya, V; Ferrante, A; Fokina, I

    1994-12-01

    Uncoupler resistance presents a potential challenge to the conventional chemiosmotic coupling mechanism. In E. coli, an adaptive response to uncouplers was found in cell growing under conditions requiring oxidative phosphorylation. It is suggested that uncoupler-resistant mutants described in the earlier literature might represent a constitutive state of expression of this "low energy shock" adaptive response. In the environment, bacteria are confronted by nonclassical uncoupling factors such as organic solvents, heat, and extremes of pH. It is suggested that the low energy shock response will aid the cell in coping with the effects of natural uncoupling factors. The genetic analysis of uncoupler resistance has only recently began, and is yielding interesting and largely unexpected results. In Bacillus subtilis, a mutation in fatty acid desaturase causes an increased content of saturated fatty acids in the membrane and increased uncoupler resistance. The protonophoric efficiency of uncouplers remains unchanged in the mutants, inviting nonorthodox interpretations of the mechanism of resistance. In E. coli, two loci conferring resistance to CCCP and TSA were cloned and were found to encode multidrug resistance pumps. Resistance to one of the uncouplers, TTFB, remained unchanged in strains mutated for the MDRs, suggesting a resistance mechanism different from uncoupler extrusion. PMID:7721726

  18. Airflow resistance in soybean

    NASA Astrophysics Data System (ADS)

    Kenghe, R. N.; Nimkar, P. M.; Shirkole, S. S.; Shinde, K. J.

    2012-04-01

    Resistance of material to airflow is an important factor to consider in the design of a dryer or an aeration system. The airflow resistance of soybean was determined with the modified airflow resistance apparatus. It was found that pressure drop increased with increase in airflow rate, bulk density, bed depth and decreased with moisture content. Modified Shedd equation, Hukill and Ives equation and modified Ergun equation were examined for pressure drop prediction. Airflow resistance was accurately described by modified Shedd equation followed by Hukill and Ives equation and modified Ergun equation. The developed statistical model comprised of airflow rate, moisture content and bulk density could fit pressure drop data reasonably well.

  19. Multidrug Resistant Acinetobacter

    PubMed Central

    Manchanda, Vikas; Sanchaita, Sinha; Singh, NP

    2010-01-01

    Emergence and spread of Acinetobacter species, resistant to most of the available antimicrobial agents, is an area of great concern. It is now being frequently associated with healthcare associated infections. Literature was searched at PUBMED, Google Scholar, and Cochrane Library, using the terms ‘Acinetobacter Resistance, multidrug resistant (MDR), Antimicrobial Therapy, Outbreak, Colistin, Tigecycline, AmpC enzymes, and carbapenemases in various combinations. The terms such as MDR, Extensively Drug Resistant (XDR), and Pan Drug Resistant (PDR) have been used in published literature with varied definitions, leading to confusion in the correlation of data from various studies. In this review various mechanisms of resistance in the Acinetobacter species have been discussed. The review also probes upon the current therapeutic options, including combination therapies available to treat infections due to resistant Acinetobacter species in adults as well as children. There is an urgent need to enforce infection control measures and antimicrobial stewardship programs to prevent the further spread of these resistant Acinetobacter species and to delay the emergence of increased resistance in the bacteria. PMID:20927292

  20. TSH resistance revisited.

    PubMed

    Narumi, Satoshi; Hasegawa, Tomonobu

    2015-01-01

    Genetic defects of hormone receptors are the most common form of end-organ hormone resistance. One example of such defects is TSH resistance, which is caused by biallelic inactivating mutations in the TSH receptor gene (TSHR). TSH, a master regulator of thyroid functions, affects virtually all cellular processes involving thyroid hormone production, including thyroidal iodine uptake, thyroglobulin iodination, reuptake of iodinated thyroglobulin and thyroid cell growth. Resistance to TSH results in defective thyroid hormone production from the neonatal period, namely congenital hypothyroidism. Classically, clinical phenotypes of TSH resistance due to inactivating TSHR mutations were thought to vary depending on the residual mutant receptor activity. Nonfunctional mutations in the two alleles produce severe thyroid hypoplasia with overt hypothyroidism (uncompensated TSH resistance), while hypomorphic mutations in at least one allele produce normal-sized thyroid gland with preserved hormone-producing capacity (compensated TSH resistance). More recently, a new subgroup of TSH resistance (nonclassic TSH resistance) that is characterized by paradoxically high thyroidal iodine uptake has been reported. In this article, the pathophysiology and clinical features of TSH resistance due to inactivating TSHR mutations are reviewed, with particular attention to the nonclassic form. PMID:25797365

  1. Mechanisms of Drug Resistance: Daptomycin Resistance

    PubMed Central

    Tran, Truc T.; Munita, Jose M.; Arias, Cesar A.

    2016-01-01

    Daptomycin (DAP) is a cyclic lipopeptide with in vitro activity against a variety of Gram-positive pathogens, including multidrug-resistant organisms. Since its introduction in clinical practice in 2003, DAP has become an important key front-line antibiotic for severe or deep-seated infections caused by Gram-positive organisms. Unfortunately, DAP-resistance (R) has been extensively documented in clinically important organisms such as Staphylococcus aureus, Enterococcus spp, and Streptococcus spp. Studies on the mechanisms of DAP-R in Bacillus subtilis and other Gram-positive bacteria indicate that the genetic pathways of DAP resistance are diverse and complex. However, a common phenomenon emerging from these mechanistic studies is that DAP-R is associated with important adaptive changes in cell wall and cell membrane homeostasis with critical changes in cell physiology. Findings related to these adaptive changes have offered novel insights into the genetics and molecular mechanisms of bacterial cell envelope stress response and the manner in which Gram-positive bacteria cope with the antimicrobial peptide attack and protect vital structures of the cell envelope such as the cell membrane. In this review, we will examine the most recent findings related to the molecular mechanisms of resistance to DAP in relevant Gram-positive pathogens and discuss the clinical implications for therapy against these important bacteria. PMID:26495887

  2. Resistance gene capture.

    PubMed

    Rowe-Magnus, D A; Mazel, D

    1999-10-01

    Integrons are the primary mechanism for antibiotic-resistance gene capture and dissemination among Gram-negative bacteria. The recent finding of super-integron structures in the genomes of several bacterial species has expanded their role in genome evolution and suggests that they are the source of mobile multi-resistant integrons. PMID:10508722

  3. Mold-Resistant Construction.

    ERIC Educational Resources Information Center

    Huckabee, Christopher

    2003-01-01

    Asserts that one of the surest ways to prevent indoor air quality and mold issues is to use preventive construction materials, discussing typical resistance to dealing with mold problems (usually budget-related) and describing mold-resistant construction, which uses concrete masonry, brick, and stone and is intended to withstand inevitable…

  4. Mechanisms of Antibiotic Resistance.

    PubMed

    Munita, Jose M; Arias, Cesar A

    2016-04-01

    Emergence of resistance among the most important bacterial pathogens is recognized as a major public health threat affecting humans worldwide. Multidrug-resistant organisms have not only emerged in the hospital environment but are now often identified in community settings, suggesting that reservoirs of antibiotic-resistant bacteria are present outside the hospital. The bacterial response to the antibiotic "attack" is the prime example of bacterial adaptation and the pinnacle of evolution. "Survival of the fittest" is a consequence of an immense genetic plasticity of bacterial pathogens that trigger specific responses that result in mutational adaptations, acquisition of genetic material, or alteration of gene expression producing resistance to virtually all antibiotics currently available in clinical practice. Therefore, understanding the biochemical and genetic basis of resistance is of paramount importance to design strategies to curtail the emergence and spread of resistance and to devise innovative therapeutic approaches against multidrug-resistant organisms. In this chapter, we will describe in detail the major mechanisms of antibiotic resistance encountered in clinical practice, providing specific examples in relevant bacterial pathogens. PMID:27227291

  5. Resistance, Reactance, and Consultation.

    ERIC Educational Resources Information Center

    Hughes, Jan N.; Falk, Robert S.

    1981-01-01

    Presents a review of techniques for dealing with consultee resistance. Suggests the social psychological theory of reactance is a useful conceptual framework for considering resistance in consultation. Discusses examples of its application, variables that predict the likely effectiveness of a reactance utilization intervention, and ethical issues.…

  6. Targeting Antibiotic Resistance.

    PubMed

    Chellat, Mathieu F; Raguž, Luka; Riedl, Rainer

    2016-06-01

    Finding strategies against the development of antibiotic resistance is a major global challenge for the life sciences community and for public health. The past decades have seen a dramatic worldwide increase in human-pathogenic bacteria that are resistant to one or multiple antibiotics. More and more infections caused by resistant microorganisms fail to respond to conventional treatment, and in some cases, even last-resort antibiotics have lost their power. In addition, industry pipelines for the development of novel antibiotics have run dry over the past decades. A recent world health day by the World Health Organization titled "Combat drug resistance: no action today means no cure tomorrow" triggered an increase in research activity, and several promising strategies have been developed to restore treatment options against infections by resistant bacterial pathogens. PMID:27000559

  7. Paraquat resistance in conyza.

    PubMed

    Fuerst, E P; Nakatani, H Y; Dodge, A D; Penner, D; Arntzen, C J

    1985-04-01

    A biotype of Conyza bonariensis (L.) Cronq. (identical to Conyza linefolia in other publications) originating in Egypt is resistant to the herbicide 1,1'-dimethyl-4,4'-bipyridinium ion (paraquat). Penetration of the cuticle by [(14)C]paraquat was greater in the resistant biotype than the susceptible (wild) biotype; therefore, resistance was not due to differences in uptake. The resistant and susceptible biotypes were indistinguishable by measuring in vitro photosystem I partial reactions using paraquat, 6,7-dihydrodipyrido [1,2-alpha:2',1'-c] pyrazinediium ion (diquat), or 7,8-dihydro-6H-dipyrido [1,2-alpha:2',1'-c] [1,4] diazepinediium ion (triquat) as electron acceptors. Therefore, alteration at the electron acceptor level of photosystem I is not the basis for resistance. Chlorophyll fluorescence measured in vivo was quenched in the susceptible biotype by leaf treatment with the bipyridinium herbicides. Resistance to quenching of in vivo chlorophyll fluorescence was observed in the resistant biotype, indicating that the herbicide was excluded from the chloroplasts. Movement of [(14)C] paraquat was restricted in the resistant biotype when excised leaves were supplied [(14)C]paraquat through the petiole. We propose that the mechanism of resistance to paraquat is exclusion of paraquat from its site of action in the chloroplast by a rapid sequestration mechanism. No differential binding of paraquat to cell walls isolated from susceptible and resistant biotypes could be detected. The exact site and mechanism of paraquat binding to sequester the herbicide remains to be determined. PMID:16664176

  8. Resistance loci affecting distinct stages of fungal pathogenesis: use of introgression lines for QTL mapping and characterization in the maize - Setosphaeria turcica pathosystem

    PubMed Central

    2010-01-01

    Background Studies on host-pathogen interactions in a range of pathosystems have revealed an array of mechanisms by which plants reduce the efficiency of pathogenesis. While R-gene mediated resistance confers highly effective defense responses against pathogen invasion, quantitative resistance is associated with intermediate levels of resistance that reduces disease progress. To test the hypothesis that specific loci affect distinct stages of fungal pathogenesis, a set of maize introgression lines was used for mapping and characterization of quantitative trait loci (QTL) conditioning resistance to Setosphaeria turcica, the causal agent of northern leaf blight (NLB). To better understand the nature of quantitative resistance, the identified QTL were further tested for three secondary hypotheses: (1) that disease QTL differ by host developmental stage; (2) that their performance changes across environments; and (3) that they condition broad-spectrum resistance. Results Among a set of 82 introgression lines, seven lines were confirmed as more resistant or susceptible than B73. Two NLB QTL were validated in BC4F2 segregating populations and advanced introgression lines. These loci, designated qNLB1.02 and qNLB1.06, were investigated in detail by comparing the introgression lines with B73 for a series of macroscopic and microscopic disease components targeting different stages of NLB development. Repeated greenhouse and field trials revealed that qNLB1.06Tx303 (the Tx303 allele at bin 1.06) reduces the efficiency of fungal penetration, while qNLB1.02B73 (the B73 allele at bin 1.02) enhances the accumulation of callose and phenolics surrounding infection sites, reduces hyphal growth into the vascular bundle and impairs the subsequent necrotrophic colonization in the leaves. The QTL were equally effective in both juvenile and adult plants; qNLB1.06Tx303 showed greater effectiveness in the field than in the greenhouse. In addition to NLB resistance, qNLB1.02B73 was

  9. AC resistance measuring instrument

    DOEpatents

    Hof, P.J.

    1983-10-04

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument. 8 figs.

  10. AC Resistance measuring instrument

    DOEpatents

    Hof, Peter J.

    1983-01-01

    An auto-ranging AC resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an AC excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance. After the auto-ranging and auto-compensation functions are complete, the microprocessor calculates the resistance of the load from the selected range resistance, the excitation signal, and the load voltage signal, and displays of the measured resistance on a digital display of the instrument.

  11. Linezolid Resistance in Staphylococci

    PubMed Central

    Stefani, Stefania; Bongiorno, Dafne; Mongelli, Gino; Campanile, Floriana

    2010-01-01

    Linezolid, the first oxazolidinone to be used clinically, is effective in the treatment of infections caused by various Gram-positive pathogens, including multidrug resistant enterococci and methicillin-resistant Staphylococus aureus. It has been used successfully for the treatment of patients with endocarditis and bacteraemia, osteomyelitis, joint infections and tuberculosis and it is often used for treatment of complicated infections when other therapies have failed. Linezolid resistance in Gram-positive cocci has been encountered clinically as well as in vitro, but it is still a rare phenomenon. The resistance to this antibiotic has been, until now, entirely associated with distinct nucleotide substitutions in domain V of the 23S rRNA genes. The number of mutated rRNA genes depends on the dose and duration of linezolid exposure and has been shown to influence the level of linezolid resistance. Mutations in associated ribosomal proteins also affect linezolid activity. A new phenicol and clindamycin resistance phenotype has recently been found to be caused by an RNA methyltransferase designated Cfr. This gene confers resistance to lincosamides, oxazolidinones, streptogramin A, phenicols and pleuromutilins, decrease the susceptibility of S. aureus to tylosin, to josamycin and spiramycin and thus differs from erm rRNA methylase genes. Research into new oxazolidinones with improved characteristics is ongoing. Data reported in patent applications demonstrated that some oxazolidinone derivatives, also with improved characteristics with respect to linezolid, are presently under study: at least three of them are in an advanced phase of development.

  12. Antibiotic Resistance Questions and Answers

    MedlinePlus

    ... on the Farm Get Smart About Antibiotics Week Antibiotic Resistance Questions and Answers Language: English Español (Spanish) Recommend ... Many ear infections Top of Page Questions about Antibiotic Resistance Examples of How Antibiotic Resistance Spreads Click for ...

  13. Resistive Exercise Device

    NASA Technical Reports Server (NTRS)

    Smith, Damon C. (Inventor)

    2005-01-01

    An exercise device 10 is particularly well suited for use in low gravity environments, and includes a frame 12 with plurality of resistance elements 30,82 supported in parallel on the frame. A load transfer member 20 is moveable relative to the frame for transferring the applied force to the free end of each captured resistance element. Load selection template 14 is removably secured both to the load transfer member, and a plurality of capture mechanisms engage the free end of corresponding resistance elements. The force applying mechanism 53 may be a handle, harness or other user interface for applying a force to move the load transfer member.

  14. Molecular cytogenetic identification of a novel 1AL.1RS translocation line with powdery mildew resistance.

    PubMed

    Lu, M; Wang, L; Zhang, J; Sun, S; Li, Y; Du, W; Wu, J; Zhao, J; Yang, Q; Chen, X

    2014-01-01

    A wheat germplasm line 13-2-2 with resistance to powdery mildew was isolated; this line was derived from common wheat cv. W770B and rye, Secale cereale L. (2n = 2x = 14, RR). The line was characterized based on cytological, genomic in situ hybridization (GISH), sequence-characterized amplified region (SCAR), and simple sequence repeat (SSR) analyses. The mitotic and meiotic investigations showed that the chromosome number and configuration of 13-2-2 were 2n = 42 = 21 II. GISH using rye genomic DNA as a probe detected a pair of R genome chromosome arms with strong hybridization signals in 13-2-2. Three 1RS chromosome-specific SCAR markers amplified 1RS specific bands in line 13-2-2. We screened 320 SSR primer pairs on the long or short arms from seven wheat homoeologous groups in the translocation line and parents. However, only three 1AS primers could not be amplified in line 13-2-2, whereas the others were amplified. Thus, these markers suggested that the line 13-2-2 was 1AL.1RS translocation line. Line 13-2-2 was immune to powdery mildew after inoculation with Blumeria graminis f. sp. tritici isolates E05 and E07 during the adult plant stages. In contrast, the maternal parent W770B, Kavkaz with Pm8, and Amigo with Pm17 were heavily infected with spores and had reaction response scores of susceptible. Thus, the new wheat-rye 1AL.1RS translocation line with resistance to powdery mildew could be a new and valuable donor source for wheat improvement. The molecular markers developed in this study might also be useful tools for marker-assisted selection. PMID:25526189

  15. All about Insulin Resistance

    MedlinePlus

    ... news is that cutting calories, being active, and losing weight can reverse insulin resistance and lower your ... you’ll lose weight. Studies have shown that losing even 7% of your weight, may help. For ...

  16. Resistance to Therapy.

    PubMed

    Rivera, Gabriel; Wakelee, Heather A

    2016-01-01

    Identification of driver mutations in adenocarcinoma of the lung has revolutionized the treatment of this disease. It is now standard of care to look for activating mutations in epidermal growth factor receptor (EGFR), and translocations in anaplastic lymphoma kinase (ALK) or ROS1 in all newly diagnosed adenocarcinoma of the lung, and in many patients with squamous cell carcinoma as well. Recognition of multiple other lung cancer driver mutations has also expanded treatment options. Targeted treatments of these mutations lead to rapid and prolonged responses, but resistance inevitably develops. Until recently, traditional chemotherapy was the only alternative at that time, but better understanding of resistance mechanisms has lead to additional therapeutic options. These mechanisms of resistance and treatments are the focus of this chapter. Understanding of mechanisms of chemotherapy resistance is touched upon, along with a brief discussion of immune checkpoint inhibitors. PMID:27535395

  17. Insulin Resistance and Prediabetes

    MedlinePlus

    ... sleep apnea; and cigarette smoking. [ Top ] Does sleep matter? Yes. Studies show that untreated sleep problems, especially ... a severe form of insulin resistance may have dark patches of skin, usually on the back of ...

  18. Temperature Coefficient of Resistance.

    ERIC Educational Resources Information Center

    Fox, John N.

    1990-01-01

    Described are the apparatus and procedures needed for a demonstration of the measurement of the electrical resistance of metals as a function of temperature using a microcomputer interface. Discussed are materials, apparatus construction, and experimental results. (CW)

  19. Skid Resistance Research

    NASA Technical Reports Server (NTRS)

    1977-01-01

    Skidding causes many traffic accidents. Streets and highways with skid-resisting surfaces reduce the incidence of such accidents. In fact, resurfacing roads to improve skid resistance is now required by federal law. Skid resistance is measured by road testing with specially equipped skid trailers. A project underway at NASA-Langley may considerably reduce the cost of skid trailers, thus making them more widely available to highway departments. For testing the skid resistance of aircraft runways, Langley engineers developed a relatively inexpensive test vehicle and a "pulsed braking" technique that is now being applied experimentally to road testing. The vehicle is a standard automobile modified to incorporate instrumentation, special test tires and valves, and a trailing fifth wheel for monitoring distance and velocity. The instrumentation includes a low-cost meter, a set of accelerometers that sense motion changes, and a chart recorder.

  20. Pathways to Tamoxifen Resistance

    PubMed Central

    Riggins, Rebecca B.; Schrecengost, Randy S.; Guerrero, Michael S.; Bouton, Amy H.

    2007-01-01

    Therapies that target the synthesis of estrogen or the function of estrogen receptor(s) have been developed to treat breast cancer. While these approaches have proven to be beneficial to a large number of patients, both de novo and acquired resistance to these drugs is a significant problem. Recent advances in our understanding of the molecular mechanisms that contribute to resistance have provided a means to begin to predict patient responses to these drugs and develop rational approaches for combining therapeutic agents to circumvent or desensitize the resistant phenotype. Here, we review common mechanisms of antiestrogen resistance and discuss the implications for prediction of response and design of effective combinatorial treatments. PMID:17475399

  1. Genetics and molecular mapping of genes for high-temperature resistance to stripe rust in wheat cultivar Xiaoyan 54.

    PubMed

    Zhou, X L; Wang, W L; Wang, L L; Hou, D Y; Jing, J X; Wang, Y; Xu, Z Q; Yao, Q; Yin, J L; Ma, D F

    2011-08-01

    Stripe rust, caused by Puccinia striiformis f. sp. tritici, is one of the most widespread and destructive wheat diseases worldwide. Growing resistant cultivars is the preferred means of control of the disease. The winter wheat cultivar Xiaoyan 54 has high-temperature resistance to stripe rust. To identify genes for stripe rust resistance, Xiaoyan 54 was crossed with Mingxian 169, a winter wheat genotype susceptible to all Chinese races of the pathogen. Seedlings and adult plants of the parents and F(1), F(2), F(3) and F(4) progeny were tested with Chinese race CYR32 under controlled greenhouse conditions and in the field. Xiaoyan 54 has two recessive resistance genes, designated as Yrxy1 and Yrxy2, conferring high-temperature resistance. Simple sequence repeat (SSR) primers were used to identify molecular markers flanking Yrxy2 using 181 plants from one segregating F(3) line. A total of nine markers, two of which flanked the locus at genetic distances of 4.0 and 6.4 cM on the long arm of chromosome 2A were identified. Resistance gene analog polymorphism (RGAP) and SSR techniques were used to identify molecular markers linked to Yrxy1. A linkage group of nine RGAP and two SSR markers was constructed for Yrxy1 using 177 plants of another segregating F(3) line. Two RGAP markers were closely linked to the locus with genetic distances of 2.3 and 3.5 cM. Amplification of a set of nulli-tetrasomic Chinese Spring lines with RGAP markers M8 and M9 and the two SSR markers located Yrxy1 on the short arm of chromosome 7A. The SSR markers Xbarc49 and Xwmc422 were 15.8 and 26.1 cM, respectively, from the gene. The closely linked molecular markers should be useful for incorporating the resistance genes into commercial cultivars and combining them with other genes for stripe rust resistance. PMID:21516354

  2. Resistant hypertension - an update.

    PubMed

    Pasha, K; Towhiduzzaman, M; Manwar, A; Jahan, M U

    2015-04-01

    Patients with hypertension are increasing in Bangladesh. Among these patients a growing number of patients are having resistant hypertension faced by both primary care physicians and specialists. There is no data regarding prevalence of resistant hypertension in Bangladesh, but clinical trials abroad suggests that it is not rare, involving perhaps 20% to 30% of study participants. Cardiovascular risk is undoubtedly increased in such patients and the condition is often complicated by multiple other cardiovascular risk factors such as obesity, sleep apnea, diabetes, and chronic kidney disease. Resistant hypertension is almost always multifactorial in etiology. Successful treatment requires identification and reversal of lifestyle factors contributing to treatment resistance; diagnosis and appropriate treatment of secondary causes of hypertension; and use of effective multi drug regimens. Studies of resistant hypertension are limited by the high cardiovascular risk of patients within this subgroup, which generally precludes safe withdrawal of medications; presence of multiple disease processes and their associated medical therapies, which confound interpretation of study results. Therefore we should concentrate on expanding our knowledge of the causes of resistant hypertension which will allow for more effective prevention and/or treatment which is essential to improve long-term clinical management of this condition. PMID:26007281

  3. Sand resistance of sunscreens.

    PubMed

    Caswell, Michael; Wood, Caryl; Martinez, Alexa

    2012-01-01

    Like water resistance in sunscreens, sand resistance in sunscreens is the ability of the sunscreen to retain its effectiveness while undergoing sand treatment. The influence of the type of sand on the sand resistance of sunscreens has not been described. The sand resistance of a control standard sunscreen, P2, and data on three grades of Quickrete commercial grade sand, #1961, #1962, and #1152, are described. These sands represent a fine sand, a medium sand, and an all-purpose sand. Using the methodology described in the 2007 proposed amendment of the Final Monograph (1) with one exception, we obtained an SPF of 16.5 (1.6) for the control standard, compared to the expected SPF of 16.3 (3.4). After a five-minute treatment of sand #1961, #1962, or #1151, the SPF of the control standard was 18.3 (1.6), 18.4 (2.0), and 17.5 (2.2), respectively. Thus, all three sands exhibited a similar sand-resistance response. Thus, there was no significant difference in the average SPF with and without sand. The medium grade sand, Quickrete commercial grade #1962, was preferred for sand-resistance testing because the fine sand was difficult to remove from the subject's backs and the coarse sand was unpleasant to the subjects. PMID:23193889

  4. Lr68: a new gene conferring slow rusting resistance to leaf rust in wheat.

    PubMed

    Herrera-Foessel, Sybil A; Singh, Ravi P; Huerta-Espino, Julio; Rosewarne, Garry M; Periyannan, Sambasivam K; Viccars, Libby; Calvo-Salazar, Violeta; Lan, Caixia; Lagudah, Evans S

    2012-05-01

    The common wheat cultivar Parula possesses a high level of slow rusting, adult plant resistance (APR) to all three rust diseases of wheat. Previous mapping studies using an Avocet-YrA/Parula recombinant inbred line (RIL) population showed that APR to leaf rust (Puccinia triticina) in Parula is governed by at least three independent slow rusting resistance genes: Lr34 on 7DS, Lr46 on 1BL, and a previously unknown gene on 7BL. The use of field rust reaction and flanking markers identified two F(6) RILs, Arula1 and Arula2, from the above population that lacked Lr34 and Lr46 but carried the leaf rust resistance gene in 7BL, hereby designated Lr68. Arula1 and Arula2 were crossed with Apav, a highly susceptible line from the cross Avocet-YrA/Pavon 76, and 396 F(4)-derived F(5) RILs were developed for mapping Lr68. The RILs were phenotyped for leaf rust resistance for over 2 years in Ciudad Obregon, Mexico, with a mixture of P. triticina races MBJ/SP and MCJ/SP. Close genetic linkages with several DNA markers on 7BL were established using 367 RILs; Psy1-1 and gwm146 flanked Lr68 and were estimated at 0.5 and 0.6 cM, respectively. The relationship between Lr68 and the race-specific seedling resistance gene Lr14b, located in the same region and present in Parula, Arula1 and Arula2, was investigated by evaluating the RILs with Lr14b-avirulent P. triticina race TCT/QB in the greenhouse. Although Lr14b and Lr68 homozygous recombinants in repulsion were not identified in RILs, γ-irradiation-induced deletion stocks that lacked Lr68 but possessed Lr14b showed that Lr68 and Lr14b are different loci. Flanking DNA markers that are tightly linked to Lr68 in a wide array of genotypes can be utilized for selection of APR to leaf rust. PMID:22297565

  5. CORRELATION OF AIRWAY RESISTANCE WITH FORCED RANDOM NOISE RESISTANCE PARAMETERS

    EPA Science Inventory

    The correlation between airway resistance (RAW) measured in a plethysmograph and three respiratory resistance parameters measured by forced random noise was evaluated. Forced random noise resistance parameters were the average resistance between 5 and 9 Hz (R5-9), the average res...

  6. Resistant starches and health.

    PubMed

    Kendall, Cyril W C; Emam, Azadeh; Augustin, Livia S A; Jenkins, David J A

    2004-01-01

    It was initially hypothesized that resistant starches, i.e., starch that enters the colon, would have protective effects on chronic colonic diseases, including reduction of colon cancer risk and in the treatment of ulcerative colitis. Recent studies have confirmed the ability of resistant starch to increase fecal bulk, increase the molar ratio of butyrate in relation to other short-chain fatty acids, and dilute fecal bile acids. However the ability of resistant starch to reduce luminal concentrations of compounds that are damaging to the colonic mucosa, including fecal ammonia, phenols, and N-nitroso compounds, still requires clear demonstration. As such, the effectiveness of resistant starch in preventing or treating colonic diseases remains to be assessed. Nevertheless, there is a fraction of what has been termed resistant (RS1) starch, which enters the colon and acts as slowly digested or lente carbohydrate in the small intestine. Foods in this class are low glycemic index and have been shown to reduce the risk of chronic disease. They have been associated with systemic physiological effects such as reduced postprandial insulin levels and higher HDL cholesterol levels. Consumption of low glycemic index foods has been shown to be related to reductions in risk of coronary heart disease and Type 2 diabetes. Type 2 diabetes has in turn been related to a higher risk of colon cancer. If carbohydrates have a protective role in colon cancer prevention this may lie partly in the systemic effects of low glycemic index foods. The colonic advantages of different carbohydrates, varying in their glycemic index and resistant starch content, therefore, remain to be determined. However, as recent positive research findings continue to mount, there is reason for optimism over the possible health advantages of those resistant starches, which are slowly digested in the small intestine. PMID:15287678

  7. Fourteen years in resistance.

    PubMed

    Livermore, David M

    2012-04-01

    Resistance trends have changed greatly over the 14 years (1997-2011) whilst I was Director of the UK Antibiotic Resistance Monitoring and Reference Laboratory (ARMRL). Meticillin-resistant Staphylococcus aureus (MRSA) first rose, then fell with improved infection control, although with the decline of one major clone beginning before these improvements. Resistant pneumococci too have declined following conjugate vaccine deployment. If the situation against Gram-positive pathogens has improved, that against Gram-negatives has worsened, with the spread of (i) quinolone- and cephalosporin-resistant Enterobacteriaceae, (ii) Acinetobacter with OXA carbapenemases, (iii) Enterobacteriaceae with biochemically diverse carbapenemases and (iv) gonococci resistant to fluoroquinolones and, latterly, cefixime. Laboratory, clinical and commercial aspects have also changed. Susceptibility testing is more standardised, with pharmacodynamic breakpoints. Treatments regimens are more driven by guidelines. The industry has fewer big profitable companies and more small companies without sales income. There is good and bad here. The quality of routine susceptibility testing has improved, but its speed has not. Pharmacodynamics adds science, but over-optimism has led to poor dose selection in several trials. Guidelines discourage poor therapy but concentrate selection onto a diminishing range of antibiotics, threatening their utility. Small companies are more nimble, but less resilient. Last, more than anything, the world has changed, with the rise of India and China, which account for 33% of the world's population and increasingly provide sophisticated health care, but also have huge resistance problems. These shifts present huge challenges for the future of chemotherapy and for the edifice of modern medicine that depends upon it. PMID:22386741

  8. Antibiotic resistance in wild birds

    PubMed Central

    Bonnedahl, Jonas

    2014-01-01

    Wild birds have been postulated as sentinels, reservoirs, and potential spreaders of antibiotic resistance. Antibiotic-resistant bacteria have been isolated from a multitude of wild bird species. Several studies strongly indicate transmission of resistant bacteria from human rest products to wild birds. There is evidence suggesting that wild birds can spread resistant bacteria through migration and that resistant bacteria can be transmitted from birds to humans and vice versa. Through further studies of the spatial and temporal distribution of resistant bacteria in wild birds, we can better assess their role and thereby help to mitigate the increasing global problem of antibiotic resistance. PMID:24697355

  9. Spore Resistance Properties.

    PubMed

    Setlow, Peter

    2014-10-01

    Spores of various Bacillus and Clostridium species are among the most resistant life forms known. Since the spores of some species are causative agents of much food spoilage, food poisoning, and human disease, and the spores of Bacillus anthracis are a major bioweapon, there is much interest in the mechanisms of spore resistance and how these spores can be killed. This article will discuss the factors involved in spore resistance to agents such as wet and dry heat, desiccation, UV and γ-radiation, enzymes that hydrolyze bacterial cell walls, and a variety of toxic chemicals, including genotoxic agents, oxidizing agents, aldehydes, acid, and alkali. These resistance factors include the outer layers of the spore, such as the thick proteinaceous coat that detoxifies reactive chemicals; the relatively impermeable inner spore membrane that restricts access of toxic chemicals to the spore core containing the spore's DNA and most enzymes; the low water content and high level of dipicolinic acid in the spore core that protect core macromolecules from the effects of heat and desiccation; the saturation of spore DNA with a novel group of proteins that protect the DNA against heat, genotoxic chemicals, and radiation; and the repair of radiation damage to DNA when spores germinate and return to life. Despite their extreme resistance, spores can be killed, including by damage to DNA, crucial spore proteins, the spore's inner membrane, and one or more components of the spore germination apparatus. PMID:26104355

  10. MSMA resistance studies.

    PubMed

    Camper, N D; Keese, R J; Coker, P S

    2004-05-01

    Monosodium methanearsonate (MSMA)-resistant and -susceptible common cocklebur (Xanthium strumarium L.) and cotton (Gossypium hirsutum L.) were treated with MSMA. Plant parameters analyzed were: glutathione synthetase activity, selected amino acid (arginine, glutamic acid, alanine, citrulline, glutamine, and glutathione) content and arsenic content (MSMA, total arsenic, and arsonate). No reduction of arsenic from the parent pentavalent form present in MSMA to the trivalent form was detected. Arginine, glutamic acid, and glutamine content increased in tissue three days after MSMA treatment. Glutathione content decreased during the first three days after treatment; however, five days after treatment the resistant biotype of cocklebur and cotton had elevated glutathione levels (8-20 times greater, respectively). Glutathione Synthetase activity was higher in cotton than in either of the cocklebur biotypes; MSMA did not affect its activity in cotton or either cocklebur biotype. Resistant biotypes have a slightly higher activity than the susceptible biotype. Tolerance of cotton to MSMA may be related to glutathione synthetase activity and possibly to the presence of phytochelatins. Also, increased glutathione levels in the resistant biotype may implicate phytochelatin involvement in the resistance mechanism. PMID:15473645

  11. Quantitative and qualitative stem rust resistance factors in barley are associated with transcriptional suppression of defense regulons.

    PubMed

    Moscou, Matthew J; Lauter, Nick; Steffenson, Brian; Wise, Roger P

    2011-07-01

    Stem rust (Puccinia graminis f. sp. tritici; Pgt) is a devastating fungal disease of wheat and barley. Pgt race TTKSK (isolate Ug99) is a serious threat to these Triticeae grain crops because resistance is rare. In barley, the complex Rpg-TTKSK locus on chromosome 5H is presently the only known source of qualitative resistance to this aggressive Pgt race. Segregation for resistance observed on seedlings of the Q21861 × SM89010 (QSM) doubled-haploid (DH) population was found to be predominantly qualitative, with little of the remaining variance explained by loci other than Rpg-TTKSK. In contrast, analysis of adult QSM DH plants infected by field inoculum of Pgt race TTKSK in Njoro, Kenya, revealed several additional quantitative trait loci that contribute to resistance. To molecularly characterize these loci, Barley1 GeneChips were used to measure the expression of 22,792 genes in the QSM population after inoculation with Pgt race TTKSK or mock-inoculation. Comparison of expression Quantitative Trait Loci (eQTL) between treatments revealed an inoculation-dependent expression polymorphism implicating Actin depolymerizing factor3 (within the Rpg-TTKSK locus) as a candidate susceptibility gene. In parallel, we identified a chromosome 2H trans-eQTL hotspot that co-segregates with an enhancer of Rpg-TTKSK-mediated, adult plant resistance discovered through the Njoro field trials. Our genome-wide eQTL studies demonstrate that transcript accumulation of 25% of barley genes is altered following challenge by Pgt race TTKSK, but that few of these genes are regulated by the qualitative Rpg-TTKSK on chromosome 5H. It is instead the chromosome 2H trans-eQTL hotspot that orchestrates the largest inoculation-specific responses, where enhanced resistance is associated with transcriptional suppression of hundreds of genes scattered throughout the genome. Hence, the present study associates the early suppression of genes expressed in this host-pathogen interaction with enhancement

  12. Insecticide Resistance in Fleas.

    PubMed

    Rust, Michael K

    2016-01-01

    Fleas are the major ectoparasite of cats, dogs, and rodents worldwide and potential vectors of animal diseases. In the past two decades the majority of new control treatments have been either topically applied or orally administered to the host. Most reports concerning the development of insecticide resistance deal with the cat flea, Ctenocephalides felis felis. Historically, insecticide resistance has developed to many of the insecticides used to control fleas in the environment including carbamates, organophosphates, and pyrethroids. Product failures have been reported with some of the new topical treatments, but actual resistance has not yet been demonstrated. Failures have often been attributed to operational factors such as failure to adequately treat the pet and follow label directions. With the addition of so many new chemistries additional monitoring of flea populations is needed. PMID:26999217

  13. Insecticide Resistance in Fleas

    PubMed Central

    Rust, Michael K.

    2016-01-01

    Fleas are the major ectoparasite of cats, dogs, and rodents worldwide and potential vectors of animal diseases. In the past two decades the majority of new control treatments have been either topically applied or orally administered to the host. Most reports concerning the development of insecticide resistance deal with the cat flea, Ctenocephalides felis felis. Historically, insecticide resistance has developed to many of the insecticides used to control fleas in the environment including carbamates, organophosphates, and pyrethroids. Product failures have been reported with some of the new topical treatments, but actual resistance has not yet been demonstrated. Failures have often been attributed to operational factors such as failure to adequately treat the pet and follow label directions. With the addition of so many new chemistries additional monitoring of flea populations is needed. PMID:26999217

  14. Solvent resistant copolyimide

    NASA Technical Reports Server (NTRS)

    Chang, Alice C. (Inventor); St. Clair, Terry L. (Inventor)

    1995-01-01

    A solvent resistant copolyimide was prepared by reacting 4,4'-oxydiphthalic anhydride with a diaimine blend comprising, based on the total amount of the diamine blend, about 75 to 90 mole percent of 3,4'-oxydianiline and about 10 to 25 mole percent p-phenylene diamine. The solvent resistant copolyimide had a higher glass transition temperature when cured at 350.degree. , 371.degree. and 400.degree. C. than LaRC.TM.-IA. The composite prepared from the copolyimide had similar mechanical properties to LaRC.TM.-IA. Films prepared from the copolyimide were resistant to immediate breakage when exposed to solvents such as dimethylacetamide and chloroform. The adhesive properties of the copolyimide were maintained even after testing at 23.degree., 150.degree., 177.degree. and 204.degree. C.

  15. Fast resistive bolometry

    SciTech Connect

    Spielman, R.B.; Deeney, C.; Fehl, D.L.; Hanson, D.L.; Keltner, N.R.; McGurn, J.S.; McKenney, J.L.

    1998-06-01

    Resistive bolometry is an accurate, robust, spectrally broadband technique for measuring absolute x-ray fluence and flux. Bolometry is an independent technique for x-ray measurements that is based on a different set of physical properties than other diagnostics such as x-ray diodes, photoconducting detectors, and P-I-N diodes. Bolometers use the temperature-driven change in element resistivity to determine the total deposited energy. The calibration of such a device is based on fundamental material properties and its physical dimensions. The authors describe the use of nickel and gold bolometers to measure x rays generated by high power Z pinches on Sandia`s Saturn and Z accelerators. The Sandia bolometer design described herein has a pulse response of {approximately}1 ns. They describe in detail the fabrication, fielding, and data analysis issues leading to highly accurate x-ray measurements. The fundamental accuracy of resistive bolometry will be discussed.

  16. Depression and Insulin Resistance

    PubMed Central

    Pearson, Sue; Schmidt, Mike; Patton, George; Dwyer, Terry; Blizzard, Leigh; Otahal, Petr; Venn, Alison

    2010-01-01

    OBJECTIVE To examine the association between depressive disorder and insulin resistance in a sample of young adults using the Composite International Diagnostic Interview to ascertain depression status. RESEARCH DESIGN AND METHODS Cross-sectional data were collected from 1,732 participants aged between 26 and 36 years. Insulin resistance was derived from blood chemistry measures of fasting insulin and glucose using the homeostasis model assessment method. Those identified with mild, moderate, or severe depression were classified as having depressive disorder. RESULTS The 12-month prevalence of depressive disorder was 5.4% among men and 11.7% among women. In unadjusted models mean insulin resistance was 17.2% (95% CI 0.7–36.0%, P = 0.04) higher in men and 11.4% (1.5–22.0%, P = 0.02) higher in women with depressive disorder. After adjustment for behavioral and dietary factors, the increased level of insulin resistance associated with depressive disorder was 13.2% (−3.1 to 32.3%, P = 0.12) in men and 6.1% (−4.1 to 17.4%, P = 0.25) in women. Waist circumference was identified as a mediator in the relationship between depression and insulin resistance, reducing the β coefficient in the fully adjusted models in men by 38% and in women by 42%. CONCLUSIONS A positive association was found between depressive disorder and insulin resistance in this population-based sample of young adult men and women. The association seemed to be mediated partially by waist circumference. PMID:20185745

  17. Vapor resistant arteries

    NASA Technical Reports Server (NTRS)

    Shaubach, Robert M. (Inventor); Dussinger, Peter M. (Inventor); Buchko, Matthew T. (Inventor)

    1989-01-01

    A vapor block resistant liquid artery structure for heat pipes. A solid tube artery with openings is encased in the sintered material of a heat pipe wick. The openings are limited to that side of the artery which is most remote from the heat source. The liquid in the artery can thus exit the artery through the openings and wet the sintered sheath, but vapor generated at the heat source is unlikely to move around the solid wall of the artery and reverse its direction in order to penetrate the artery through the openings. An alternate embodiment uses finer pore size wick material to resist vapor entry.

  18. Flame Resistant Foam

    NASA Technical Reports Server (NTRS)

    1984-01-01

    Solimide manufactured by Imi-Tech Corporation, is a lightweight fire resistant material produced under a manufacturing process that allows it to be uniformly foamed. Can be produced in a variety of densities and structural configurations and remains resilient under exposure to temperatures ranging from minus 300 to plus 500 degrees Fahrenheit. Is resistant to open flame and generates virtually no smoke or toxic by-products. Used in aircraft for its superior damping characteristics, lighter weight and fire barrier properties, it's also applicable to ships and surface transportation systems such as transit cars, trains, buses and automobiles.

  19. Tackling antibiotic resistance

    PubMed Central

    Bush, Karen; Courvalin, Patrice; Dantas, Gautam; Davies, Julian; Eisenstein, Barry; Huovinen, Pentti; Jacoby, George A.; Kishony, Roy; Kreiswirth, Barry N.; Kutter, Elizabeth; Lerner, Stephen A.; Levy, Stuart; Lewis, Kim; Lomovskaya, Olga; Miller, Jeffrey H.; Mobashery, Shahriar; Piddock, Laura J. V.; Projan, Steven; Thomas, Christopher M.; Tomasz, Alexander; Tulkens, Paul M.; Walsh, Timothy R.; Watson, James D.; Witkowski, Jan; Witte, Wolfgang; Wright, Gerry; Yeh, Pamela; Zgurskaya, Helen I.

    2014-01-01

    The development and spread of antibiotic resistance in bacteria is a universal threat to both humans and animals that is generally not preventable, but can nevertheless be controlled and must be tackled in the most effective ways possible. To explore how the problem of antibiotic resistance might best be addressed, a group of thirty scientists from academia and industry gathered at the Banbury Conference Centre in Cold Spring Harbor, New York, May 16-18, 2011. From these discussions emerged a priority list of steps that need to be taken to resolve this global crisis. PMID:22048738

  20. A Piggyback resistive Micromegas

    NASA Astrophysics Data System (ADS)

    Attié, D.; Chaus, A.; Colas, P.; Ferrer Ribas, E.; Galán, J.; Giomataris, I.; Gongadze, A.; Iguaz, F. J.; De Oliveira, R.; Papaevangelou, T.; Peyaud, A.

    2013-05-01

    A novel read-out architecture has been developed for the Micromegas detector. The anode element is made of a resistive layer on a ceramic substrate. The detector part is entirely separated from the read-out element. Without significant loss, signals are transmitted by capacitive coupling to the read-out pads. The detector provides high gas gain, good energy resolution and the resistive layer assures spark protection to the electronics. This assembly could be combined with modern pixel array electronic ASICs. This readout organization is free on how the pixels are designed, arranged and connected. We present first results taken with a Medipix2 read-out chip.

  1. Resisting religious coercive control.

    PubMed

    Sharp, Shane

    2014-12-01

    Religious coercive control refers to the use of religious beliefs and doctrine as means to coercively control intimate partners. Scholars have shown that some abusive partners use the Christian doctrine of submission as a means of religious coercive control. I explore how victims who experience the doctrine of submission qua religious coercive control actively resist it. I argue that victims' successful resistance of the doctrine is contingent on their religious capital-that is, the knowledge and mastery that people have of a particular religious culture-and interpretive confidence-that is, people's subjective confidence in their interpretations of religious culture-related to the doctrine. PMID:25398370

  2. Shatter-Resistant, Flame-Resistant Window

    NASA Technical Reports Server (NTRS)

    Richardson, William R.; Walker, Ernie D.

    1989-01-01

    Combustion-chamber window combines properties of polycarbonate and sapphire. Inner layer of sapphire, withstands flame in chamber. Outer layer of polycarbonate tough but susceptible to weakening by flame and protected from flame by sapphire layer. Resists flames, shattering, and high pressure. Windows withstand 60 lb/in. to second power (414 kPa) in hydrostatic pressure vessel. Also survives leak test under internal pressure of 2 atm (0.2 MPa) of helium and external pressure of 10 to negative fifth power torr (1.3 mPa). Has transmission density of 0.08 to 0.11 in visible light. In contrast, unbonded layers have transmission density of 0.13 to 0.16.

  3. [Resistance risk, cross-resistance and biochemical resistance mechanism of Laodelphax striatellus to buprofezin].

    PubMed

    Mao, Xu-lian; Liu, Jin; Li, Xu-ke; Chi, Jia-jia; Liu, Yong-jie

    2016-01-01

    In order to investigate the resistance development law and biochemical resistance mechanism of Laodelphax striatellus to buprofezin, spraying rice seedlings was used to continuously screen resistant strains of L. striatellus and dipping rice seedlings was applied to determine the toxicity and cross-resistance of L. striatellus to insecticides. After 32-generation screening with buprofezin, L. striatellus developed 168.49 folds resistance and its reality heritability (h2) was 0.11. If the killing rate was 80%-90%, L. striatellus was expected to develop 10-fold resistance to buprofezin only after 5 to 6 generations breeding. Because the actual reality heritability of field populations was usually lower than that of the resistant strains, the production of field populations increasing with 10-fold resistance would need much longer time. The results of cross-resistance showed that resistant strain had high level cross-resistance with thiamethoxam and imidacloprid, low level cross-resistance with acetamiprid, and no cross-resistance with pymetrozine and chlorpyrifos. The activity of detoxification enzymes of different strains and the syergism of synergist were measured. The results showed that cytochrome P450 monooxygenase played a major role in the resistance of L. striatellus to buprofezin, the esterase played a minor role and the GSH-S-transferase had no effect. Therefore, L. striatellus would have high risk to develop resistance to buprofezin when used in the field and might be delayed by using pymetrozine and chlorpyrifos. PMID:27228617

  4. Intestinal colonization resistance

    PubMed Central

    Lawley, Trevor D; Walker, Alan W

    2013-01-01

    Dense, complex microbial communities, collectively termed the microbiota, occupy a diverse array of niches along the length of the mammalian intestinal tract. During health and in the absence of antibiotic exposure the microbiota can effectively inhibit colonization and overgrowth by invading microbes such as pathogens. This phenomenon is called ‘colonization resistance’ and is associated with a stable and diverse microbiota in tandem with a controlled lack of inflammation, and involves specific interactions between the mucosal immune system and the microbiota. Here we overview the microbial ecology of the healthy mammalian intestinal tract and highlight the microbe–microbe and microbe–host interactions that promote colonization resistance. Emerging themes highlight immunological (T helper type 17/regulatory T-cell balance), microbiota (diverse and abundant) and metabolic (short-chain fatty acid) signatures of intestinal health and colonization resistance. Intestinal pathogens use specific virulence factors or exploit antibiotic use to subvert colonization resistance for their own benefit by triggering inflammation to disrupt the harmony of the intestinal ecosystem. A holistic view that incorporates immunological and microbiological facets of the intestinal ecosystem should facilitate the development of immunomodulatory and microbe-modulatory therapies that promote intestinal homeostasis and colonization resistance. PMID:23240815

  5. Genetics of disease resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic resistance is alluring from both the industrial and academic viewpoints. With respect to poultry companies, losses due to diseases induced by infectious pathogens continue to be a significant issue and can be the key factor in determining economic viability. This is because pathogens lead ...

  6. Antimicrobial (Drug) Resistance Prevention

    MedlinePlus

    ... Action Plan for Combating Antibiotic-Resistant Bacteria (PDF) ​​​​​​ Javascript Error Your browser JavaScript is turned off causing certain features of the ... incorrectly. Please visit your browser settings and turn JavaScript on. Read more information on enabling JavaScript. Skip ...

  7. Teaching, Learning, and Resistance

    ERIC Educational Resources Information Center

    Van de Kleut, Geraldine; White, Connie

    2010-01-01

    This article is a discussion of the importance of using student resistance to inform and change teacher practice. The authors relate two narratives of practice, one of which takes place in a constructivist second-grade classroom in Ontario, and a second that takes place in a preservice classroom in California. In the first, a student uses the…

  8. Overcoming Resistance to Change

    ERIC Educational Resources Information Center

    Hull, Ted H.; Balka, Don S.; Miles, Ruth Harbin

    2010-01-01

    Resistance to change is a major obstacle in developing and implementing effective instructional programs, yet it is rarely considered, discussed, or addressed. The school leaders who are responsible for improvement frequently feel that their efforts are being blocked or thwarted. For the most part, they are correct, but they may not realize that…

  9. Antibiotic-Resistant Bacteria.

    ERIC Educational Resources Information Center

    Longenecker, Nevin E.; Oppenheimer, Dan

    1982-01-01

    A study conducted by high school advanced bacteriology students appears to confirm the hypothesis that the incremental administration of antibiotics on several species of bacteria (Escherichia coli, Staphylococcus epidermis, Bacillus sublitus, Bacillus megaterium) will allow for the development of antibiotic-resistant strains. (PEB)

  10. Wear resistant valve

    NASA Technical Reports Server (NTRS)

    Perkins, Gerald S. (Inventor)

    1980-01-01

    A valve which is resistant to wear caused by particles trapped between the valve seat and the valve member or poppet when the valve closes, including an outlet for directing washing fluid at the valve seat and/or sealing face of the poppet and means for supplying pressured fluid to the outlet at the time when the valve is closing.

  11. Penetration resistant barrier

    DOEpatents

    Hoover, William R.; Mead, Keith E.; Street, Henry K.

    1977-01-01

    The disclosure relates to a barrier for resisting penetration by such as hand tools and oxy-acetylene cutting torches. The barrier comprises a layer of firebrick, which is preferably epoxy impregnated sandwiched between inner and outer layers of steel. Between the firebrick and steel are layers of resilient rubber-like filler.

  12. POTATO DISEASE RESISTANCE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The potential to use systemic acquired resistance for disease control in potato is discussed. The mechanism of how SAR works in plants is described. Potato was found to have high salicylic acid levels in all tissues examined. The defense gene PR-1 was constitutively expressed in potato, in contrast ...

  13. Herbicide Resistant Weed Management

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Metribuzin and rimsulfuron are the only two herbicides registered for postemergence broadleaf weed control in potatoes, and represent the two classes of herbicides, triazines and ALS inhibitors, with the most reported cases of resistant weeds world wide. Other postemergence grass herbicides belongin...

  14. Resistance Management Research Status

    EPA Science Inventory

    Long-term sustainability of genetically modified corn expressing Bt relies on the validity of assumptions underlying IRM models used by the EPA and the ability of EPA to monitor, detect and react to insect resistance when it develops. The EPA is developing a multi-tiered approac...

  15. Piggyback resistive Micromegas

    NASA Astrophysics Data System (ADS)

    Attié, D.; Chaus, A.; Durand, D.; Desforge, D.; Ferrer-Ribas, E.; Galán, J.; Giomataris, Y.; Gongadze, A.; Iguaz, F. J.; Jeanneau, F.; de Oliveira, R.; Papaevangelou, T.; Peyaud, A.; Teixeira, A.

    2013-11-01

    Piggyback Micromegas is a novel readout architecture where the anode element is made of a resistive layer on a ceramic substrate. The resistive layer is deposited on the thin ceramic substrate by an industrial process which provides a large dynamic range of resistivity (106 to 1010 MΩ/square). The particularity of this new structure is that the active part is entirely dissociated from the read-out element. This gives a large flexibility on the design of the anode structure and the readout scheme. Without significant loss, signals are transmitted by capacitive coupling to the read-out pads. The detector provides high gas gain, good energy resolution and the resistive layer assures spark protection for the electronics. This assembly could be combined with modern pixel array electronic ASICs. First tests with different Piggyback detectors and configurations will be presented. This structure is adequate for cost effective fabrication and low out gazing detector. It was designed to perform in sealed mode and its long term stability has been extensively studied. In addition perspectives on the future developments will be evoked.

  16. Treatment of resistant epilepsy.

    PubMed

    Pickrell, William Owen; Smith, Phil E M

    2014-12-01

    Treatment resistance affects around 20% of people with epilepsy and carries a significant comorbidity. It is important to ensure that the diagnosis of epilepsy is secure and the underlying cause of the epilepsy is investigated thoroughly. Management involves early referral for epilepsy surgery when suitable, optimisation of pharmacological treatment, and consideration of comorbidities such as depression. PMID:25468911

  17. Fluoroquinolone resistance in Campylobacter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fluoroquinolone-resistant Campylobacter jejuni and C. coli are common in animals because of the use of fluoroquinolones as therapeutic agents in animal husbandry, particularly in chickens and other poultry. Campylobacter is a commensal in poultry, and therefore, poultry and poultry products are the...

  18. Wrinkle resistant cellulosic textiles

    SciTech Connect

    Kitchens, J.D.; Patton, R.T.; Nadar, R.S.

    1991-08-27

    This patent describes a process for treating a cellulosic textile material so as to impart wrinkle resistance and smooth drying properties. It comprises treating the cellulosic textile material with an aqueous solution comprising trans-1,2,3,4-cyclobutane tetracarboxylic acid, and a curing catalyst, and heating the treated material so as to produce esterification and crosslinking of the material with the acid.

  19. Electrical Resistivity Imaging

    EPA Science Inventory

    Electrical resistivity imaging (ERI) is a geophysical method originally developed within the mining industry where it has been used for decades to explore for and characterize subsurface mineral deposits. It is one of the oldest geophysical methods with the first documented usag...

  20. Antimicrobial (Drug) Resistance: Vancomycin-Resistant Enterococci (VRE) Frequently Asked Questions

    MedlinePlus

    ... Understanding Antimicrobial (Drug) Resistance Examples of Antimicrobial Resistance Methicillin-Resistant Staphylococcus aureus (MRSA) Vancomycin-Resistant Enterococci (VRE) Overview Transmission Diagnosis ...

  1. Confirmation of resistance to herbicides and evaluation of resistance levels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As cases of resistance to herbicides escalate worldwide, there is increasing demand from growers to test for weed resistance and how to manage it. Scientists have developed resistance testing protocols for numerous herbicides and weed species. Growers need immediate answers and scientists are faced ...

  2. Cross resistances in spinosad-resistant Culex quinquefasciatus (Diptera: Culicidae).

    PubMed

    Su, Tianyun; Cheng, Min-Lee

    2014-03-01

    A Culex quinquefasciatus Say colony was selected for 45 generations at LC70-90 levels using Natular XRG, a granular formulation of 2.5% spinosad for induction of spinosad resistance. Resistance to spinosad was noticed in early generations (F1-F9). Resistance levels increased gradually from generations F11-F35, and elevated significantly from generation F37 through F47, when resistance ratios reached 2,845-2,907-fold at LC50 and 11,948-22,928-fold at LC90 The spinosad-resistant Cx. quinquefasciatus colony was found not to be cross-resistant to Bacillus thuringiensis israelensis (Bti), a combination of Bti and Bacillus sphaericus, methoprene, pyriproxyfen, diflubenzuron, novaluron, temephos, or imidacloprid. However, it showed various levels of cross-resistance to B. sphaericus, spinetoram, abamectin, and fipronil. Conversely, a laboratory colony of Cx. quinquefasciatus that is highly resistant to B. sphaericus did not show cross-resistance to spinosad and spinetoram. Field-collected and laboratory-selected Cx. quinquefasciatus that showed low to moderate resistance to methoprene did not show cross-resistance to spinosad and spinetoram. Mechanisms of cross-resistance among several biorational pesticides were discussed according to their modes of actions. PMID:24724293

  3. Are Sewage Treatment Plants Promoting Antibiotic Resistance?

    EPA Science Inventory

    1. Introduction 1.1. How bacteria exhibit resistance 1.1.1. Resistance to -lactams 1.1.2. Resistance to sulphonamides and trimethoprim 1.1.3. Resistance to macrolides 1.1.4. Resistance to fluoroquinolones 1.1.5. Resistance to tetracyclines 1.1.6. Resistance to nitroimidaz...

  4. MDRO - Multidrug-Resistant Organisms

    MedlinePlus

    ... MRSA in the workplace, see: Methicillin-resistan t Staphylococcus aure us (MRSA) . Provides links with general information, ... of these organisms include: MRSA - Methicillin/oxacillin-resistant Staphylococcus aureus VRE - Vancomycin-resistant enterococci ESBLs - Extended-spectrum ...

  5. Galileo's Trajectory with Mild Resistance

    ERIC Educational Resources Information Center

    Groetsch, C. W.

    2012-01-01

    An aspect of Galileo's classical trajectory that persists in a simple resistance model is noted. The resistive model provides a case study for the classroom analysis of limiting behaviour of an implicitly defined function. (Contains 1 note.)

  6. USDA Data on Antimicrobial Resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antimicrobial susceptibility testing remains an important tool as investigators devise ways to arrest the development of antimicrobial resistance, particularly in food borne bacteria. In 1996, the Food and Drug Administration (FDA) initiated the National Antimicrobial Resistance Monitoring System -...

  7. Corrosion-resistant metal surfaces

    DOEpatents

    Sugama, Toshifumi

    2009-03-24

    The present invention relates to metal surfaces having thereon an ultrathin (e.g., less than ten nanometer thickness) corrosion-resistant film, thereby rendering the metal surfaces corrosion-resistant. The corrosion-resistant film includes an at least partially crosslinked amido-functionalized silanol component in combination with rare-earth metal oxide nanoparticles. The invention also relates to methods for producing such corrosion-resistant films.

  8. Insulin Resistance of Puberty.

    PubMed

    Kelsey, Megan M; Zeitler, Philip S

    2016-07-01

    Puberty is a time of considerable metabolic and hormonal change. Notably, puberty is associated with a marked decrease in insulin sensitivity, on par with that seen during pregnancy. In otherwise healthy youth, there is a nadir in insulin sensitivity in mid-puberty, and then it recovers at puberty completion. However, there is evidence that insulin resistance (IR) does not resolve in youth who are obese going into puberty and may result in increased cardiometabolic risk. Little is known about the underlying pathophysiology of IR in puberty, and how it might contribute to increased disease risk (e.g., type 2 diabetes). In this review, we have outlined what is known about the IR in puberty in terms of pattern, potential underlying mechanisms and other mediating factors. We also outline other potentially related metabolic changes that occur during puberty, and effects of underlying insulin resistant states (e.g., obesity) on pubertal changes in insulin sensitivity. PMID:27179965

  9. [Prevention, why resist it?].

    PubMed

    Laurin, J C

    1989-01-01

    Prevention, why resist it? Based on a 1988 speech the author gave to infection control professionals in Montréal, this article draws a parallel between individuals' resistance to change and their reaction to infection control programs. Gladly, many of the same well-honed techniques that help change along can be applied to infection control efforts, he says. Analyzing the implementation of an infection control program for AIDS in a health center, the author emphasizes do's and don'ts and explores appropriate and inappropriate approaches to leadership, conflict prevention and problem solving. To sell your program, he says, you must also sell yourself; you must be convincing and credible. PMID:2912544

  10. Stress corrosion resistant fasteners

    NASA Technical Reports Server (NTRS)

    Roach, T. A.

    1985-01-01

    A family of high performance aerospace fasteners made from corrosion resistant alloys for use in applications where corrosion and stress-corrosion cracking are of major concern are discussed. The materials discussed are mainly A-286, Inconel 718, MP35N and MP159. Most of the fasteners utilize cold worked and aged materials to achieve the desired properties. The fasteners are unique in that they provide a combination of high strength and immunity to stress corrosion cracking not previously attainable. A discussion of fastener stress corrosion failures is presented including a review of the history and a description of the mechanism. Case histories are presented to illustrate the problems which can arise when material selection is made without proper regard for the environmental conditions. Mechanical properties and chemical compositions are included for the fasteners discussed. Several aspects of the application of high performance corrosion resistant fasteners are discussed including galvanic compatibility and torque-tension relationships.

  11. Electrical resistivity probes

    DOEpatents

    Lee, Ki Ha; Becker, Alex; Faybishenko, Boris A.; Solbau, Ray D.

    2003-10-21

    A miniaturized electrical resistivity (ER) probe based on a known current-voltage (I-V) electrode structure, the Wenner array, is designed for local (point) measurement. A pair of voltage measuring electrodes are positioned between a pair of current carrying electrodes. The electrodes are typically about 1 cm long, separated by 1 cm, so the probe is only about 1 inch long. The electrodes are mounted to a rigid tube with electrical wires in the tube and a sand bag may be placed around the electrodes to protect the electrodes. The probes can be positioned in a borehole or on the surface. The electrodes make contact with the surrounding medium. In a dual mode system, individual probes of a plurality of spaced probes can be used to measure local resistance, i.e. point measurements, but the system can select different probes to make interval measurements between probes and between boreholes.

  12. String resistance detector

    NASA Technical Reports Server (NTRS)

    Hall, A. Daniel (Inventor); Davies, Francis J. (Inventor)

    2007-01-01

    Method and system are disclosed for determining individual string resistance in a network of strings when the current through a parallel connected string is unknown and when the voltage across a series connected string is unknown. The method/system of the invention involves connecting one or more frequency-varying impedance components with known electrical characteristics to each string and applying a frequency-varying input signal to the network of strings. The frequency-varying impedance components may be one or more capacitors, inductors, or both, and are selected so that each string is uniquely identifiable in the output signal resulting from the frequency-varying input signal. Numerical methods, such as non-linear regression, may then be used to resolve the resistance associated with each string.

  13. Corrosive resistant heat exchanger

    DOEpatents

    Richlen, Scott L.

    1989-01-01

    A corrosive and errosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is conveyed through ducts or perforations in the heat exchanger wall. Heat from the heat stream is transferred by radiation to the heat exchanger wall. Heat is removed from the outer heat exchanger wall by a heat recovery medium.

  14. Antimicrobial Resistance in Agriculture

    PubMed Central

    Thanner, Sophie; Drissner, David

    2016-01-01

    ABSTRACT In this article, the current knowledge and knowledge gaps in the emergence and spread of antimicrobial resistance (AMR) in livestock and plants and importance in terms of animal and human health are discussed. Some recommendations are provided for generation of the data required in order to develop risk assessments for AMR within agriculture and for risks through the food chain to animals and humans. PMID:27094336

  15. Emerging and Resistant Infections

    PubMed Central

    Kalil, Andre C.; Fowler, Vance G.; Ghedin, Elodie; Kolls, Jay K.; Nguyen, M. Hong

    2014-01-01

    The lungs are a major target for infection and a key battleground in the fight against the development of antimicrobial drug–resistant pathogens. Ventilator-associated pneumonia (VAP) is associated with mortality rates of 24–50%. The optimal duration of antibiotic therapy against VAP is unknown, but prolonged courses are associated with the emergence of bacterial resistance. De-escalation strategies in which treatment is discontinued based on signs of clinical resolution, fixed durations of therapy (generally 7–8 d), or serum procalcitonin responses have been shown to decrease antibiotic consumption. Outcomes are comparable to longer treatment courses, with the possible exception of VAP due to nonfermenting, gram-negative bacilli such as Pseudomonas aeruginosa. Staphylococcus aureus is a leading cause of VAP and other infections. Outcomes after S. aureus infection are shaped by the interplay between environmental, bacterial, and host genetic factors. It is increasingly clear that mechanisms of pathogenesis vary in different types of S. aureus infections. Genome-scale studies of S. aureus strains, host responses, and host genetics are redefining our understanding of the pathogenic mechanisms underlying VAP. Genome-sequencing technologies are also revolutionizing our understanding of the molecular epidemiology, evolution, and transmission of influenza. Deep sequencing using next-generation technology platforms is defining the remarkable genetic diversity of influenza strains within infected hosts. Investigators have demonstrated that antiviral drug-resistant influenza may be present prior to the initiation of treatment. Moreover, drug-resistant minor variant influenza strains can be transmitted from person to person in the absence of selection pressure. Studies of lung infections and the causative pathogens will remain at the cutting edge of clinical and basic medical research. PMID:25148425

  16. Abrasion resistant heat pipe

    DOEpatents

    Ernst, Donald M.

    1984-10-23

    A specially constructed heat pipe for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.

  17. Abrasion resistant heat pipe

    DOEpatents

    Ernst, D.M.

    1984-10-23

    A specially constructed heat pipe is described for use in fluidized bed combustors. Two distinct coatings are spray coated onto a heat pipe casing constructed of low thermal expansion metal, each coating serving a different purpose. The first coating forms aluminum oxide to prevent hydrogen permeation into the heat pipe casing, and the second coating contains stabilized zirconium oxide to provide abrasion resistance while not substantially affecting the heat transfer characteristics of the system.

  18. Achieving a Low Ground Resistance using Critical Resistance Area Concept

    NASA Astrophysics Data System (ADS)

    Eduful, George; Cole, Joseph Ekow; Okyere, Philip Yaw

    2010-06-01

    Based on response curves derived from field measurements, optimum number of vertical ground electrodes for grounding electrical installation is determined. On sites where the optimum number of the electrodes cannot reach a target ground resistance, a `critical resistance area concept' with conductive backfills is used. In this study, efficiencies of local conductive backfills for reducing ground resistance are investigated. Results show that application of tyre ashes as a conductive backfills lowers ground resistance to over 80%. It is also shown that the most favourable benefit in the ground resistance improvement is to limit the backfill to four ground electrodes.

  19. Heat resistant protective hand covering

    NASA Technical Reports Server (NTRS)

    Tschirch, R. P.; Sidman, K. R.; Arons, I. J. (Inventor)

    1984-01-01

    A heat-resistant aromatic polyamide fiber is described. The outer surface of the shell is coated with a fire-resistant elastomer and liner. Generally conforming and secured to the shell and disposed inwardly of the shell, the liner is made of a felt fabric of temperature-resistant aromatic polymide fiber.

  20. Investigating the Antibiotic Resistance Problem.

    ERIC Educational Resources Information Center

    Lawson, Michael; Lawson, Amy L.

    1998-01-01

    Seeks to give teachers useful information on the extent of the problem of antibiotic-resistant bacteria, mechanisms bacteria use to resist antibiotics, the causes of the emergence of antibiotic-resistant organisms, and practices that can prevent or reverse this trend. Contains 19 references. (DDR)

  1. Studying Resistance: Some Cautionary Notes

    ERIC Educational Resources Information Center

    Dimitriadis, Greg

    2011-01-01

    The question of "resistance" has oriented the field of critical ethnography for several generations now. Indeed, the reproduction-resistance binary has animated much of the most important, critical work in educational studies over the last 30 years. Yet, this reproduction-resistance binary has perhaps calcified in recent years. Such work often…

  2. Biotechnology: herbicide-resistant crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Transgenic, herbicide-resistant (HR) crops are planted on about 80% of the land covered by transgenic crops. More than 90% of HR crios are glyphosate-resistant (GR) crops, the others being resistant to glufosinate. The wide-scale adoption of HR crops, largely for economic reasons, has been the mos...

  3. Testing Tools for Glyphosate Resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There are multiple tools available for testing for glyphosate resistance. Whole plant screens, whether in the field or greenhouse, should be used as an initial method to determine if a biotype is glyphosate resistant. Screening for resistance using seedling assays such as in Petri plates, sand cul...

  4. Resistant hypertension and chronotherapy.

    PubMed

    Prkacin, Ingrid; Balenovic, Diana; Djermanovic-Dobrota, Vesna; Lukac, Iva; Drazic, Petra; Pranjic, Iva-Klara

    2015-04-01

    Resistant hypertension is defined as blood pressure that remains above 140/90 mmHg in spite of the continuous use of three antihypertensive agents in optimal dose, including diuretic, and lifestyle changes. According to data from United States of America and Europe, the prevalence ranges from 10 up to 30% in patients with hypertension. Numerous biological and lifestyle factors can contribute to the development of resistant hypertension: medications, volume overload, obesity, diabetes mellitus, older age, renal parenchymal and renovascular disease, primary aldosteronism, obstructive sleep apnea, pheochormocytoma, Cushing's syndrome, thyroid diseases, aortic coarctation. For diagnosing patient's history is important, assessing compliance, regular blood pressure measurement, physical examination, biochemical evaluation and noninvasive imaging. The evaluation including 24h ambulatory monitoring of blood pressure (ABPM) in the identification of "non-dipper" hypertension. Non-dipper has particular importance and the prevalence of abnormally high sleep blood pressure is very often in chronic kidney patients. Therapeutic restoration of normal physiologic blood pressure reduction during night-time sleep (circadial variation) is the most significant independent predictor of decreased risk and the basis for the chronotherapy. The resistant hypertension treatment is achieved with nonpharmacological and pharmacological approach, treating secondary hypertension causes and invasive procedures. PMID:26005390

  5. Resistant Hypertension and Chronotherapy

    PubMed Central

    Prkacin, Ingrid; Balenovic, Diana; Djermanovic-Dobrota, Vesna; Lukac, Iva; Drazic, Petra; Pranjic, Iva-Klara

    2015-01-01

    Resistant hypertension is defined as blood pressure that remains above 140/90 mmHg in spite of the continuous use of three antihypertensive agents in optimal dose, including diuretic, and lifestyle changes. According to data from United States of America and Europe, the prevalence ranges from 10 up to 30% in patients with hypertension. Numerous biological and lifestyle factors can contribute to the development of resistant hypertension: medications, volume overload, obesity, diabetes mellitus, older age, renal parenchymal and renovascular disease, primary aldosteronism, obstructive sleep apnea, pheochormocytoma, Cushing’s syndrome, thyroid diseases, aortic coarctation. For diagnosing patient’s history is important, assessing compliance, regular blood pressure measurement, physical examination, biochemical evaluation and noninvasive imaging. The evaluation including 24h ambulatory monitoring of blood pressure (ABPM) in the identification of “non-dipper” hypertension. Non-dipper has particular importance and the prevalence of abnormally high sleep blood pressure is very often in chronic kidney patients. Therapeutic restoration of normal physiologic blood pressure reduction during night-time sleep (circadial variation) is the most significant independent predictor of decreased risk and the basis for the chronotherapy. The resistant hypertension treatment is achieved with nonpharmacological and pharmacological approach, treating secondary hypertension causes and invasive procedures. PMID:26005390

  6. Thyroid hormone resistance.

    PubMed

    Olateju, Tolulope O; Vanderpump, Mark P J

    2006-11-01

    Resistance to thyroid hormone (RTH) is a rare autosomal dominant inherited syndrome of reduced end-organ responsiveness to thyroid hormone. Patients with RTH have elevated serum free thyroxine (FT4) and free triiodothyronine (FT3) concentrations and normal or slightly elevated serum thyroid stimulating hormone (TSH) level. Despite a variable clinical presentation, the common characteristic clinical features are goitre but an absence of the usual symptoms and metabolic consequences of thyroid hormone excess. Patients with RTH can be classified on clinical grounds alone into either generalized resistance (GRTH), pituitary resistance (PRTH) or combined. Mutations in the thyroid hormone receptor (TR) beta gene are responsible for RTH and 122 different mutations have now been identified belonging to 300 families. With the exception of one family found to have complete deletion of the TRbeta gene, all others have been demonstrated to have minor alterations at the DNA level. The differential diagnosis includes a TSH-secreting pituitary adenoma and the presence of endogenous antibodies directed against thyroxine (T4) and triiodothyronine (T3). Failure to differentiate RTH from primary thyrotoxicosis has resulted in the inappropriate treatment of nearly one-third of patients. Although occasionally desirable, no specific treatment is available for RTH; however, the diagnosis allows appropriate genetic counselling. PMID:17132274

  7. Surveillance of antibiotic resistance

    PubMed Central

    Johnson, Alan P.

    2015-01-01

    Surveillance involves the collection and analysis of data for the detection and monitoring of threats to public health. Surveillance should also inform as to the epidemiology of the threat and its burden in the population. A further key component of surveillance is the timely feedback of data to stakeholders with a view to generating action aimed at reducing or preventing the public health threat being monitored. Surveillance of antibiotic resistance involves the collection of antibiotic susceptibility test results undertaken by microbiology laboratories on bacteria isolated from clinical samples sent for investigation. Correlation of these data with demographic and clinical data for the patient populations from whom the pathogens were isolated gives insight into the underlying epidemiology and facilitates the formulation of rational interventions aimed at reducing the burden of resistance. This article describes a range of surveillance activities that have been undertaken in the UK over a number of years, together with current interventions being implemented. These activities are not only of national importance but form part of the international response to the global threat posed by antibiotic resistance. PMID:25918439

  8. Drug resistance in leishmaniasis.

    PubMed

    Croft, Simon L; Sundar, Shyam; Fairlamb, Alan H

    2006-01-01

    Leishmaniasis is a complex disease, with visceral and cutaneous manifestations, and is caused by over 15 different species of the protozoan parasite genus Leishmania. There are significant differences in the sensitivity of these species both to the standard drugs, for example, pentavalent antimonials and miltefosine, and those on clinical trial, for example, paromomycin. Over 60% of patients with visceral leishmaniasis in Bihar State, India, do not respond to treatment with pentavalent antimonials. This is now considered to be due to acquired resistance. Although this class of drugs has been used for over 60 years for leishmaniasis treatment, it is only in the past 2 years that the mechanisms of action and resistance have been identified, related to drug metabolism, thiol metabolism, and drug efflux. With the introduction of new therapies, including miltefosine in 2002 and paromomycin in 2005-2006, it is essential that there be a strategy to prevent the emergence of resistance to new drugs; combination therapy, monitoring of therapy, and improved diagnostics could play an essential role in this strategy. PMID:16418526

  9. Targeting molecular resistance in castration-resistant prostate cancer.

    PubMed

    Chandrasekar, Thenappan; Yang, Joy C; Gao, Allen C; Evans, Christopher P

    2015-01-01

    Multiple mechanisms of resistance contribute to the inevitable progression of hormone-sensitive prostate cancer to castration-resistant prostate cancer (CRPC). Currently approved therapies for CRPC include systemic chemotherapy (docetaxel and cabazitaxel) and agents targeting the resistance pathways leading to CRPC, including enzalutamide and abiraterone. While there is significant survival benefit, primary and secondary resistance to these therapies develops rapidly. Up to one-third of patients have primary resistance to enzalutamide and abiraterone; the remaining patients eventually progress on treatment. Understanding the mechanisms of resistance resulting in progression as well as identifying new targetable pathways remains the focus of current prostate cancer research. We review current knowledge of mechanisms of resistance to the currently approved treatments, development of adjunctive therapies, and identification of new pathways being targeted for therapeutic purposes. PMID:26329698

  10. Degenerate resistive switching and ultrahigh density storage in resistive memory

    SciTech Connect

    Lohn, Andrew J. Mickel, Patrick R. James, Conrad D.; Marinella, Matthew J.

    2014-09-08

    We show that in tantalum oxide resistive memories, activation power provides a multi-level variable for information storage that can be set and read separately from the resistance. These two state variables (resistance and activation power) can be precisely controlled in two steps: (1) the possible activation power states are selected by partially reducing resistance, then (2) a subsequent partial increase in resistance specifies the resistance state and the final activation power state. We show that these states can be precisely written and read electrically, making this approach potentially amenable for ultra-high density memories. We provide a theoretical explanation for information storage and retrieval from activation power and experimentally demonstrate information storage in a third dimension related to the change in activation power with resistance.

  11. Allocation of the S-genome chromosomes of Aegilops variabilis Eig. carrying powdery mildew resistance in triticale (× Triticosecale Wittmack).

    PubMed

    Kwiatek, M; Belter, J; Majka, M; Wiśniewska, H

    2016-03-01

    It has been hypothesized that the powdery mildew adult plant resistance (APR) controlled by the Pm13 gene in Aegilops longissima Schweinf. & Muschl. (S(l)S(l)) has been evolutionary transferred to Aegilops variabilis Eig. (UUSS). The molecular marker analysis and the visual evaluation of powdery mildew symptoms in Ae. variabilis and the Ae. variabilis × Secale cereale amphiploid forms (2n = 6x = 42, UUSSRR) showed the presence of product that corresponded to Pm13 marker and the lower infection level compared to susceptible model, respectively. This study also describes the transfer of Ae. variabilis Eig. (2n = 4x = 28, U(v)U(v)S(v)S(v)) chromosomes, carrying powdery mildew resistance, into triticale (× Triticosecale Wittm., 2n = 6x = 42, AABBRR) using Ae. variabilis × S. cereale amphiploid forms. The individual chromosomes of Ae. variabilis, triticale 'Lamberto' and hybrids were characterized by genomic and fluorescence in situ hybridization (GISH/FISH). The chromosome configurations of obtained hybrid forms were studied at first metaphase of meiosis of pollen mother cells (PMCs) using GISH. The statistical analysis showed that the way of S-genome chromosome pairing and transmission to subsequent hybrid generations was diploid-like and had no influence on chromosome pairing of triticale chromosomes. The cytogenetic study of hybrid forms were supported by the marker-assisted selection using Pm13 marker and visual evaluation of natural infection by Blumeria graminis, that allowed to select the addition or substitution lines of hybrids carrying chromosome 3S(v) which were tolerant to the powdery mildew infection. PMID:25868512

  12. Herbicide-resistant crops and weed resistance to herbicides.

    PubMed

    Owen, Micheal D K; Zelaya, Ian A

    2005-03-01

    The adoption of genetically modified (GM) crops has increased dramatically during the last 3 years, and currently over 52 million hectares of GM crops are planted world-wide. Approximately 41 million hectares of GM crops planted are herbicide-resistant crops, which includes an estimated 33.3 million hectares of herbicide-resistant soybean. Herbicide-resistant maize, canola, cotton and soybean accounted for 77% of the GM crop hectares in 2001. However, sugarbeet, wheat, and as many as 14 other crops have transgenic herbicide-resistant cultivars that may be commercially available in the near future. There are many risks associated with the production of GM and herbicide-resistant crops, including problems with grain contamination, segregation and introgression of herbicide-resistant traits, marketplace acceptance and an increased reliance on herbicides for weed control. The latter issue is represented in the occurrence of weed population shifts, the evolution of herbicide-resistant weed populations and herbicide-resistant crops becoming volunteer weeds. Another issue is the ecological impact that simple weed management programs based on herbicide-resistant crops have on weed communities. Asiatic dayflower (Commelina cumminus L) common lambsquarters (Chenopodium album L) and wild buckwheat (Polygonum convolvulus L) are reported to be increasing in prominence in some agroecosystems due to the simple and significant selection pressure brought to bear by herbicide-resistant crops and the concomitant use of the herbicide. Finally, evolution of herbicide-resistant weed populations attributable to the herbicide-resistant crop/herbicide program has been observed. Examples of herbicide-resistant weeds include populations of horseweed (Conyza canadensis (L) Cronq) resistant to N-(phosphonomethyl)glycine (glyphosate). An important question is whether or not these problems represent significant economic issues for future agriculture. PMID:15668920

  13. Molecular Detection of Antimicrobial Resistance

    PubMed Central

    Fluit, Ad C.; Visser, Maarten R.; Schmitz, Franz-Josef

    2001-01-01

    The determination of antimicrobial susceptibility of a clinical isolate, especially with increasing resistance, is often crucial for the optimal antimicrobial therapy of infected patients. Nucleic acid-based assays for the detection of resistance may offer advantages over phenotypic assays. Examples are the detection of the methicillin resistance-encoding mecA gene in staphylococci, rifampin resistance in Mycobacterium tuberculosis, and the spread of resistance determinants across the globe. However, molecular assays for the detection of resistance have a number of limitations. New resistance mechanisms may be missed, and in some cases the number of different genes makes generating an assay too costly to compete with phenotypic assays. In addition, proper quality control for molecular assays poses a problem for many laboratories, and this results in questionable results at best. The development of new molecular techniques, e.g., PCR using molecular beacons and DNA chips, expands the possibilities for monitoring resistance. Although molecular techniques for the detection of antimicrobial resistance clearly are winning a place in routine diagnostics, phenotypic assays are still the method of choice for most resistance determinations. In this review, we describe the applications of molecular techniques for the detection of antimicrobial resistance and the current state of the art. PMID:11585788

  14. The insecticide-resistance problem

    PubMed Central

    Brown, A. W. A.

    1958-01-01

    The author reviews the growth of the insecticide-resistance problem throughout the world during the period between July 1956 and November 1957, and the developments in research on the subject during the same period. Three new resistant species have been discovered—Anopheles subpictus, Chrysomyia putoria and Rhipicephalus sanguineus—and eight new types of resistance in already resistant species have been observed. Moreover, the geographical area covered by certain resistant insect populations has considerably increased. The research accomplishments during the period under review include: systems of detecting resistance in the field by standard test methods; confirmation of two distinct types of resistance to chlorinated-hydrocarbon insecticides in mosquitos and bed-bugs as well as in houseflies; evidence that DDT-resistance in the housefly, Anopheles sundaicus and Aëdes aegypti is due mainly to a single genetic factor associated with the ability to dehydrochlorinate DDT, and that dieldrin-resistance of Anopheles gambiae also derives from a single factor present even in untouched populations; a fuller understanding of the physiological mechanism of BHC-resistance in the housefly; and demonstration that selection pressure from organo-phosphorus compounds induces resistance to themselves and to chlorinated-hydrocarbon insecticides. PMID:13536795

  15. Resistance-induced antibiotic substitution.

    PubMed

    Howard, David H

    2004-06-01

    In many cases, physicians prescribe antibiotics without knowing whether an individual patient is infected with a susceptible or resistant pathogen. As the proportion of resistant organisms in a community increases, physicians substitute away from older-inexpensive drugs to newer, more expensive agents as first line therapy. This paper explores the implications of resistance-induced antibiotic substitution for epidemiological models to predict future resistance levels, efforts to measure the health care costs associated with resistance, and policies to improve physicians' antibiotic prescribing decisions. The extent of resistance-induced substitution in outpatient settings is documented using a data set consisting of observations on initial physician office visits for otitis media in the US controlling for new product introductions and price increases, per prescription antibiotic spending increased by 22% between 1980 and 1996, corresponding to a steep increase in resistance levels over the same period. PMID:15185388

  16. Outwitting the series resistance in scanning spreading resistance microscopy.

    PubMed

    Schulze, A; Cao, R; Eyben, P; Hantschel, T; Vandervorst, W

    2016-02-01

    The performance of nanoelectronics devices critically depends on the distribution of active dopants inside these structures. For this reason, dopant profiling has been defined as one of the major metrology challenges by the international technology roadmap of semiconductors. Scanning spreading resistance microscopy (SSRM) has evolved as one of the most viable approaches over the last decade due to its excellent spatial resolution, sensitivity and quantification accuracy. However, in case of advanced device architectures like fins and nanowires a proper measurement of the spreading resistance is often hampered by the increasing impact of parasitic series resistances (e.g. bulk series resistance) arising from the confined nature of the aforementioned structures. In order to overcome this limitation we report in this paper the development and implementation of a novel SSRM mode (fast Fourier transform-SSRM: FFT-SSRM) which essentially decouples the spreading resistance from parasitic series resistance components. We show that this can be achieved by a force modulation (leading to a modulated spreading resistance signal) in combination with a lock-in deconvolution concept. In this paper we first introduce the principle of operation of the technique. We discuss in detail the underlying physical mechanisms as well as the technical implementation on a state-of-the-art atomic force microscope (AFM). We demonstrate the performance of FFT-SSRM and its ability to remove substantial series resistance components in practice. Eventually, the possibility of decoupling the spreading resistance from the intrinsic probe resistance will be demonstrated and discussed. PMID:26624516

  17. Corrosion-resistant uranium

    DOEpatents

    Hovis, Jr., Victor M.; Pullen, William C.; Kollie, Thomas G.; Bell, Richard T.

    1983-01-01

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  18. Corrosion-resistant uranium

    SciTech Connect

    Bell, R.T.; Hovis, V.M.; Kollie, T.G.; Pullen, W.C.

    1983-05-31

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  19. Corrosion-resistant uranium

    DOEpatents

    Hovis, V.M. Jr.; Pullen, W.C.; Kollie, T.G.; Bell, R.T.

    1981-10-21

    The present invention is directed to the protecting of uranium and uranium alloy articles from corrosion by providing the surfaces of the articles with a layer of an ion-plated metal selected from aluminum and zinc to a thickness of at least 60 microinches and then converting at least the outer surface of the ion-plated layer of aluminum or zinc to aluminum chromate or zinc chromate. This conversion of the aluminum or zinc to the chromate form considerably enhances the corrosion resistance of the ion plating so as to effectively protect the coated article from corrosion.

  20. Treatment-Resistant Schizophrenia.

    PubMed

    Elkis, Helio; Buckley, Peter F

    2016-06-01

    Although treatment-resistant schizophrenia (TRS) was described 50 years ago and has a gold standard treatment with clozapine based on well-defined criteria, there is still a matter of great interest and controversy. In terms of the underlying mechanisms of the development of TRS, progress has been made for the elucidation of the neurochemical mechanisms. Structural neuroimaging studies have shown that patients with TRS have significant reduction of the prefrontal cortex volume when compared with non- TRS. This article updates and enhances our previous review with new evidence mainly derived from new studies, clinical trials, systematic reviews, and meta-analyses. PMID:27216902

  1. Abrasion resistant composition

    DOEpatents

    Fischer, Keith D; Barnes, Christopher A; Henderson, Stephen L

    2014-05-13

    A surface covering composition of abrasion resistant character adapted for disposition in overlying bonded relation to a metal substrate. The surface covering composition includes metal carbide particles within a metal matrix at a packing factor of not less than about 0.6. Not less than about 40 percent by weight of the metal carbide particles are characterized by an effective diameter in the range of +14-32 mesh prior to introduction to the metal matrix. Not less than about 3 percent by weight of the metal carbide particles are characterized by an effective diameter of +60 mesh prior to introduction to the metal matrix.

  2. Ceftobiprole- and ceftaroline-resistant methicillin-resistant Staphylococcus aureus.

    PubMed

    Chan, Liana C; Basuino, Li; Diep, Binh; Hamilton, Stephanie; Chatterjee, Som S; Chambers, Henry F

    2015-05-01

    The role of mecA mutations in conferring resistance to ceftobiprole and ceftaroline, cephalosporins with anti-methicillin-resistant Staphylococcus aureus (MRSA) activity, was determined with MRSA strains COL and SF8300. The SF8300 ceftaroline-passaged mutant carried a single mecA mutation, E447K (E-to-K change at position 447), and expressed low-level resistance. This mutation in COL conferred high-level resistance to ceftobiprole but only low-level resistance to ceftaroline. The COL ceftaroline-passaged mutant, which expressed high-level resistance to ceftobiprole and ceftaroline, had mutations in pbp2, pbp4, and gdpP but not mecA. PMID:25753637

  3. Measuring The Contact Resistances Of Photovoltaic Cells

    NASA Technical Reports Server (NTRS)

    Burger, D. R.

    1985-01-01

    Simple method devised to measure contact resistances of photovoltaic solar cells. Method uses readily available equipment and applicable at any time during life of cell. Enables evaluation of cell contact resistance, contact-end resistance, contact resistivity, sheet resistivity, and sheet resistivity under contact.

  4. Upper airway resistance syndrome.

    PubMed

    Hasan, N; Fletcher, E C

    1998-07-01

    Many clinicians are familiar with the clinical symptoms and signs of obstructive sleep apnea (OSA). In its most blatant form, OSA is complete airway obstruction with repetitive, prolonged pauses in breathing, arterial oxyhemoglobin desaturation; followed by arousal with resumption of breathing. Daytime symptoms of this disorder include excessive daytime somnolence, intellectual dysfunction, and cardiovascular effects such as systemic hypertension, angina, myocardial infarction, and stroke. It has been recently recognized that increased pharyngeal resistance with incomplete obstruction can lead to a constellation of symptoms identical to OSA called "upper airway resistance syndrome" (UARS). The typical findings of UARS on sleep study are: (1) repetitive arousals from EEG sleep coinciding with a (2) waxing and waning of the respiratory airflow pattern and (3) increased respiratory effort as measured by esophageal pressure monitoring. There may be few, if any, obvious apneas or hypopneas with desaturation, but snoring may be a very prominent finding. Treatment with nasal positive airway pressure (NCPAP) eliminates the symptoms and confirms the diagnosis. Herein we describe two typical cases of UARS. PMID:9676067

  5. Oxidation Resistant Graphite Studies

    SciTech Connect

    W. Windes; R. Smith

    2014-07-01

    The Very High Temperature Reactor (VHTR) Graphite Research and Development Program is investigating doped nuclear graphite grades exhibiting oxidation resistance. During a oxygen ingress accident the oxidation rates of the high temperature graphite core region would be extremely high resulting in significant structural damage to the core. Reducing the oxidation rate of the graphite core material would reduce the structural effects and keep the core integrity intact during any air-ingress accident. Oxidation testing of graphite doped with oxidation resistant material is being conducted to determine the extent of oxidation rate reduction. Nuclear grade graphite doped with varying levels of Boron-Carbide (B4C) was oxidized in air at nominal 740°C at 10/90% (air/He) and 100% air. The oxidation rates of the boronated and unboronated graphite grade were compared. With increasing boron-carbide content (up to 6 vol%) the oxidation rate was observed to have a 20 fold reduction from unboronated graphite. Visual inspection and uniformity of oxidation across the surface of the specimens were conducted. Future work to determine the remaining mechanical strength as well as graphite grades with SiC doped material are discussed.

  6. Resistive hydrogen sensing element

    DOEpatents

    Lauf, Robert J.

    2000-01-01

    Systems and methods are described for providing a hydrogen sensing element with a more robust exposed metallization by application of a discontinuous or porous overlay to hold the metallization firmly on the substrate. An apparatus includes: a substantially inert, electrically-insulating substrate; a first Pd containing metallization deposited upon the substrate and completely covered by a substantially hydrogen-impermeable layer so as to form a reference resistor on the substrate; a second Pd containing metallization deposited upon the substrate and at least a partially accessible to a gas to be tested, so as to form a hydrogen-sensing resistor; a protective structure disposed upon at least a portion of the second Pd containing metallization and at least a portion of the substrate to improve the attachment of the second Pd containing metallization to the substrate while allowing the gas to contact said the second Pd containing metallization; and a resistance bridge circuit coupled to both the first and second Pd containing metallizations. The circuit determines the difference in electrical resistance between the first and second Pd containing metallizations. The hydrogen concentration in the gas may be determined. The systems and methods provide advantages because adhesion is improved without adversely effecting measurement speed or sensitivity.

  7. Fast Resistive Bolometry

    NASA Astrophysics Data System (ADS)

    Graham, Jeffrey

    2005-10-01

    A bolometer with microsecond scale response time is under construction for the Caltech spheromak experiment to measure radiation from a ˜20 μs duration plasma discharge emitting ˜10^2---10^3 kW/m^2. A gold film several micrometers thick absorbs the radiation, heats up, and the consequent change in resistance can be measured. The film itself is vacuum deposited upon a glass slide. Several geometries for the film are under consideration to optimize the amount of radiation absorbed, the response time and the signal-to-noise ratio. We measure the change in voltage across the film for a known current driven through it; a square pulse (3---30A, ˜20 μs) is used to avoid Joule heating. Results from prototypes tested with a UV flashlamp will be presented. After optimizing the bolometer design, the final vacuum-compatible diagnostic would consist of a plasma-facing bolometer and a reference in a camera obscura. This device could provide a design for fast resistive bolometry.

  8. Resistance electroslag (RES) surfacing

    SciTech Connect

    Forsberg, S.G.

    1985-08-01

    RES-surfacing is an abbreviation of resistance electroslag surfacing. The ElectroSlag Welding (ESW) process is wellknown for the welding of heavy-walled materials. During the past few years, a RES-surfacing system has been developed, in which a strip electrode is used in an ESW process. This is a development of the submerged arc welding (SAW) surfacing process using strip electrodes, which has been used in industry for many years. The basic difference between the SAW- and RES-surfacing processes is in the way of obtaining penetration in the base metal, and in fusion of the strip electrode and flux. In the SAW process, the required heat is derived from an electric arc; in the RES-process, it is obtained by resistance heating (i.e., the Joule effect) as a result of current flowing through a shallow molten pool of electrically conductive slag. To satisfy the basic differences in the processes, specific combinations of strip electrodes and fluxes have been developed. The welding equipment used for RES-surfacing is basically the same as for SAW-surfacing, except for minor modifications of the welding head due to heat radiation from the visible molten slag pool, and the use of additional equipment for magnetic control of the molten pool. result of the magnetic control of the molten pool.

  9. Atrazine Resistance in Chenopodium album

    PubMed Central

    Bettini, Priscilla; McNally, Sheila; Sevignac, Mireille; Darmency, Henri; Gasquez, Jacques; Dron, Michel

    1987-01-01

    In Chenopodium album two different levels of atrazine resistance have been found according to following criteria: lethal dose and leaf fluorescence curve. The intermediate (I) phenotype is represented by a low level of resistance and a typical I fluorescence curve. It arose at high frequency, within one generation, after self-pollination of particular plants displaying a susceptible (S) phenotype. The resistance phenotype (Ri) has a high level of resistance and presents a typical resistant fluorescence curve. It appeared after self-pollination of chemically treated I plants. The I, Ri, and also R (resistant plants found in atrazine treated fields) phenotypes contain a serine to glycine mutation at amino acid position 264 in the chloroplast psbA gene product. The steady state level of the psbA gene transcript is not modified between S, I, Ri, and R phenotypes. Images Fig. 4 PMID:16665624

  10. The Prehistory of Antibiotic Resistance.

    PubMed

    Perry, Julie; Waglechner, Nicholas; Wright, Gerard

    2016-01-01

    Antibiotic resistance is a global problem that is reaching crisis levels. The global collection of resistance genes in clinical and environmental samples is the antibiotic "resistome," and is subject to the selective pressure of human activity. The origin of many modern resistance genes in pathogens is likely environmental bacteria, including antibiotic producing organisms that have existed for millennia. Recent work has uncovered resistance in ancient permafrost, isolated caves, and in human specimens preserved for hundreds of years. Together with bioinformatic analyses on modern-day sequences, these studies predict an ancient origin of resistance that long precedes the use of antibiotics in the clinic. Understanding the history of antibiotic resistance is important in predicting its future evolution. PMID:27252395

  11. Fluconazole resistance in Candida glabrata.

    PubMed Central

    Hitchcock, C A; Pye, G W; Troke, P F; Johnson, E M; Warnock, D W

    1993-01-01

    We report a case of infection with Candida glabrata in which the organism became resistant to fluconazole and in which pre- and posttreatment isolates were available for comparison. The organism was cross-resistant to ketoconazole and itraconazole, in common with other azole-resistant yeasts. Fluconazole was a potent inhibitor of cytochrome P-450-dependent 14 alpha-sterol demethylase (P-450DM) in lysates of cells from both susceptible and resistant cultures (50% inhibitory concentration, 0.2 microM), indicating that resistance was unrelated to changes in P-450DM. Instead, it appeared to arise from a permeability barrier to fluconazole, since resistant cells were unable to take up radiolabelled drug. PMID:8239613

  12. Clopidogrel resistance: The way forward

    PubMed Central

    Ray, Shuvanan

    2014-01-01

    Clopidogrel, a second generation thienopyridine has been the mainstay of ACS (Acute Coronary Syndrome) treatment for more than a decade. Clopidogrel Resistance has been associated with increased mortality in ACS patients with an increase in number of Stent Thrombosis. This review article tries to find out the causes of Clopidogrel Resistance, the main factors involving it, Laboratory evaluation of Clopidogrel Resistance. The overall incidence of Clopidogrel Resistance across the Globe & India has also been considered. The article also discusses the clinical significance of Clopidogrel Resistance & its relationship with adverse cardiovascular events. This review ends with the probable solutions to Clopidogrel Resistance & the new generation of antiplatelets which can be used for the same. PMID:25443607

  13. Metoclopramide and renal vascular resistance.

    PubMed

    Manara, A R; Bolsin, S; Monk, C R; Hartnell, G; Harris, R A

    1991-01-01

    We have studied the effect of i.v. metoclopramide on renal vascular resistance in nine healthy volunteers. Peak systolic and end-diastolic frequencies were measured using duplex Doppler ultrasound of a renal interlobar artery, before and after the administration of i.v. metoclopramide 10 mg, and the resistance index derived. There was no significant change in mean arterial pressure or resistance index following metoclopramide. PMID:1997046

  14. Mechanisms of resistance to cabazitaxel.

    PubMed

    Duran, George E; Wang, Yan C; Francisco, E Brian; Rose, John C; Martinez, Francisco J; Coller, John; Brassard, Diana; Vrignaud, Patricia; Sikic, Branimir I

    2015-01-01

    We studied mechanisms of resistance to the novel taxane cabazitaxel in established cellular models of taxane resistance. We also developed cabazitaxel-resistant variants from MCF-7 breast cancer cells by stepwise selection in drug alone (MCF-7/CTAX) or drug plus the transport inhibitor PSC-833 (MCF-7/CTAX-P). Among multidrug-resistant (MDR) variants, cabazitaxel was relatively less cross-resistant than paclitaxel and docetaxel (15- vs. 200-fold in MES-SA/Dx5 and 9- vs. 60-fold in MCF-7/TxT50, respectively). MCF-7/TxTP50 cells that were negative for MDR but had 9-fold resistance to paclitaxel were also 9-fold resistant to cabazitaxel. Selection with cabazitaxel alone (MCF-7/CTAX) yielded 33-fold resistance to cabazitaxel, 52-fold resistance to paclitaxel, activation of ABCB1, and 3-fold residual resistance to cabazitaxel with MDR inhibition. The MCF-7/CTAX-P variant did not express ABCB1, nor did it efflux rhodamine-123, BODIPY-labeled paclitaxel, and [(3)H]-docetaxel. These cells are hypersensitive to depolymerizing agents (vinca alkaloids and colchicine), have reduced baseline levels of stabilized microtubules, and impaired tubulin polymerization in response to taxanes (cabazitaxel or docetaxel) relative to MCF-7 parental cells. Class III β-tubulin (TUBB3) RNA and protein were elevated in both MCF-7/CTAX and MCF-7/CTAX-P. Decreased BRCA1 and altered epithelial-mesenchymal transition (EMT) markers are also associated with cabazitaxel resistance in these MCF-7 variants, and may serve as predictive biomarkers for its activity in the clinical setting. In summary, cabazitaxel resistance mechanisms include MDR (although at a lower level than paclitaxel and docetaxel), and alterations in microtubule dynamicity, as manifested by higher expression of TUBB3, decreased BRCA1, and by the induction of EMT. PMID:25416788

  15. Persistence, resistance, resonance

    NASA Astrophysics Data System (ADS)

    Tsadka, Maayan

    Sound cannot travel in a vacuum, physically or socially. The ways in which sound operates are a result of acoustic properties, and the ways by which it is considered to be music are a result of social constructions. Therefore, music is always political, regardless of its content: the way it is performed and composed; the choice of instrumentation, notation, tuning; the medium of its distribution; its inherent hierarchy and power dynamics, and more. My compositional praxis makes me less interested in defining a relationship between music and politics than I am in erasing---or at least blurring---the borders between them. In this paper I discuss the aesthetics of resonance and echo in their metaphorical, physical, social, and musical manifestations. Also discussed is a political aesthetic of resonance, manifested through protest chants. I transcribe and analyze common protest chants from around the world, categorizing and unifying them as universal crowd-mobilizing rhythms. These ideas are explored musically in three pieces. Sumud: Rhetoric of Resistance in Three Movements, for two pianos and two percussion players, is a musical interpretation of the political/social concept of sumud, an Arabic word that literally means "steadfastness" and represents Palestinian non-violent resistance. The piece is based on common protest rhythms and uses the acoustic properties inherent to the instruments. The second piece, Three Piano Studies, extends some of the musical ideas and techniques used in Sumud, and explores the acoustic properties and resonance of the piano. The final set of pieces is part of my Critical Mess Music Project. These are site-specific musical works that attempt to blur the boundaries between audience, performers and composer, in part by including people without traditional musical training in the process of music making. These pieces use the natural structure and resonance of an environment, in this case, locations on the UCSC campus, and offer an active

  16. Powdery Mildew Disease Resistance

    SciTech Connect

    Somerville, Shauna C.

    2010-08-31

    The overall goal of this project was to characterize the PMR5 protein, a member of the DUF231/TBR family, and to determine its role in plant cell wall biogenesis. Since the pmr5 mutants are also resistant to the fungal powdery mildew pathogen, we wished to determine what specific cell wall changes are associated with disease resistance and why. The graduate student working on this project made mutations in the putative active site of PMR5, assuming it is a member of the SGNH/GDSL esterase superfamily (Anantharaman and Aravind, 2010, Biology Direct 5, 1). These mutants were inactive in planta suggesting that PMR5 is a functional enzyme and not a binding protein or chaperone. In addition, she determined that cell wall preparations from the pmr5 mutant exhibited a modest reduction (13%) in total acetyl groups. To pursue characterization further, the graduate student expressed the PMR5 protein in a heterologous E. coli system. She could purify PMR5 using a two step protocol based on tags added to the N and C terminus of the protein. She was able to show the PMR5 protein bound to pectins, including homogalacturonan, but not to other cell wall components (e.g., xyloglucans, arabinans). Based on these observations, a postdoctoral fellow is currently developing an enzyme assay for PMR5 based on the idea that it may be acetylating the homogalacturonic acid pectin fraction. Our initial experiments to localize PMR5 subcellularly suggested that it occurred in the endoplasmic reticulum. However, since the various pectins are believed to be synthesized in the Golgi apparatus, we felt it necessary to repeat our results using a native promoter expression system. Within the past year, we have demonstrated conclusively that PMR5 is localized to the endoplasmic reticulum, a location that sets it apart from most cell wall biogenesis and modification enzymes. The graduate student contributed to the characterization of two suppressor mutants, which were selected as restoring powdery

  17. Resistance training and sarcopenia.

    PubMed

    Giallauria, Francesco; Cittadini, Antonio; Smart, Neil Andrew; Vigorito, Carlo

    2016-01-01

    Aging is inexorably accompanied by a progressive decline of muscle mass, quality and strength. The resulting condition has been termed sarcopenia. Age-related sarcopenia can be accelerated by a variety of factors including changes in the hormonal milieu, inactivity, poor nutrition, chronic illness, and loss of integrity and function in the peripheral and central nervous systems. The downstream mechanisms by which these risk factors cause sarcopenia are not completely understood. Exercise training (particularly resistance training) has long been identified as the most promising method for increasing muscle mass and strength among older people. New interventions aimed at preventing muscle atrophy, promoting muscle growth and ultimately, maintaining muscle functions during aging are discussed. Understanding how age affects muscle-related gene expression, protein recycling and resynthesis, post-translational modification and turnover will be crucial to identify new treatment options. PMID:27374049

  18. Scratch-Resistant Lenses

    NASA Technical Reports Server (NTRS)

    1996-01-01

    Lewis Research Center developed a process for achieving diamond- hard coatings for aerospace systems. The technique involves coating the material with a film of diamond-like carbon (DLC) using direct ion deposition. An ion generator creates a stream of ions from a hydrocarbon gas source; the carbon ions impinge directly on the target substrate and 'grow' into a thin DLC film. In 1988, Air Products and Chemicals, Inc. received a license to the NASA patent. Diamonex, an Air Products spinoff company, further developed the NASA process to create the DiamondHard technology used on the Bausch & Lomb Ray- Ban Survivors sunglasses. The sunglasses are scratch-resistant and shed water more easily, thus reducing spotting.

  19. Full range resistive thermometers

    NASA Astrophysics Data System (ADS)

    Olivieri, E.; Rotter, M.; De Combarieu, M.; Forget, P.; Marrache-Kikuchi, C.; Pari, P.

    2015-12-01

    Resistive thermometers are widely used in low temperature physics, thanks to portability, simplicity of operation and reduced size. The possibility to precisely follow the temperature from room temperature down to the mK region is of major interest for numerous applications, although no single thermometer can nowadays cover this entire temperature range. In this article we report on a method to realize a full range thermometer, capable to measure, by itself, temperatures in the whole above-cited temperature range, with constant sensitivity and sufficient precision for the typical cryogenic applications. We present here the first results for three different full range thermometer prototypes. A detailed description of the set-up used for measurements and characterization is also reported.

  20. Herbicide-resistant crops, resistant weeds, and herbicide drift

    Technology Transfer Automated Retrieval System (TEKTRAN)

    New herbicide-resistance traits in corn and soybean may bring new management challenges for fruit and vegetable growers in the Mid-Atlantic region. Herbicide-resistant crops are an important weed management technology in row crop agriculture that allow growers to apply an herbicide to control weed...

  1. Is Resistance Useless? Multidrug Resistance and Collateral Sensitivity

    PubMed Central

    Hall, Matthew D.; Handley, Misty D.; Gottesman, Michael M.

    2009-01-01

    When cancer cells develop resistance to chemotherapeutics, it is frequently conferred by the ATP-dependent efflux pump P-glycoprotein (MDR1, P-gp, ABCB1). P-gp can efflux a wide range of cancer drugs; thus its expression confers cross-resistance, termed multidrug resistance (MDR), to a wide range of drugs. Strategies to overcome this resistance have been actively sought for over 30 years, yet no clinical solutions exist. A less understood aspect of MDR is the hypersensitivity of resistant cancer cells to other drugs, a phenomenon generally known as collateral sensitivity (CS). This review highlights the extent of this effect for the first time, discusses hypotheses such as ROS generation to account for the underlying generality of this phenomenon, and proposes the exploitation of CS as a strategy to improve response to chemotherapy. PMID:19762091

  2. Inducing Resistance to Misleading Information.

    ERIC Educational Resources Information Center

    Greene, Edith; And Others

    1982-01-01

    Presents study designed to explore whether warning people about the possibility of future misinformation would increase their resistance to that misinformation. Results show exposure to a warning just prior to presentation of misinformation resulted in slightly greater resistance to its suggestive effects, but warnings after misinformation had…

  3. Sorghum germplasm resistance to anthracnose

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Anthracnose is one of the most damaging diseases for sorghum production. The disease can be successfully managed through the use of resistant cultivars, but the development of resistant cultivars is hindered by extensive variation in virulence within the pathogen population. Additional sources of ...

  4. Flame resistant elastic elastomeric fiber

    NASA Technical Reports Server (NTRS)

    Howarth, J. T.; Sheth, S.; Massucco, A. A.; Sidman, K. R.

    1974-01-01

    Compositions exhibit elastomeric properties and possess various degrees of flame resistance. First material polyurethane, incorporates halogen containing polyol and is flame resistant in air; second contains spandex elastomer with flame retardant additives; and third material is prepared from fluorelastomer composition of copolymer of vinylidene fluoride and hexafluoropropylene.

  5. Dealing with Resistance to Change

    ERIC Educational Resources Information Center

    Williamson, Ronald; Blackburn, Barbara R.

    2010-01-01

    One of the biggest roadblocks to addressing instructional rigor in schools is the resistance to change that is displayed by teachers, students, parents, and other building and district leaders. Every person deals differently with change. Some are more accepting, others more resistant. No change is successful if the people being asked to change…

  6. USEPA Resistance Management Model development

    EPA Science Inventory

    The US EPA requires registrants of plant incorporated protectant (PIP) crops to provide information relating to the time frame for pest resistance development related to the control traits of the crop. Simulation models are used to evaluate the future conditions for resistance de...

  7. Methods of airway resistance assessment.

    PubMed

    Urbankowski, Tomasz; Przybyłowski, Tadeusz

    2016-01-01

    Airway resistance is the ratio of driving pressure to the rate of the airflow in the airways. The most frequent methods used to measure airway resistance are whole-body plethysmography, the interrupter technique and the forced oscillation technique. All these methods allow to measure resistance during respiration at the level close to tidal volume, they do not require forced breathing manoeuvres or deep breathing during measurement. The most popular method for measuring airway resistance is whole-body plethysmography. The results of plethysmography include among others the following parameters: airway resistance (Raw), airway conductance (Gaw), specific airway resistance (sRaw) and specific airway conductance (sGaw). The interrupter technique is based on the assumption that at the moment of airway occlusion, air pressure in the mouth is equal to the alveolar pressure . In the forced oscillation technique (FOT), airway resistance is calculated basing on the changes in pressure and flow caused by air vibration. The methods for measurement of airway resistance that are described in the present paper seem to be a useful alternative to the most common lung function test - spirometry. The target group in which these methods may be widely used are particularly the patients who are unable to perform spirometry. PMID:27238174

  8. Antibiotic resistance: a physicist's view.

    PubMed

    Allen, Rosalind; Waclaw, Bartłomiej

    2016-01-01

    The problem of antibiotic resistance poses challenges across many disciplines. One such challenge is to understand the fundamental science of how antibiotics work, and how resistance to them can emerge. This is an area where physicists can make important contributions. Here, we highlight cases where this is already happening, and suggest directions for further physics involvement in antimicrobial research. PMID:27510596

  9. Corrosion resistant PEM fuel cell

    DOEpatents

    Fronk, Matthew Howard; Borup, Rodney Lynn; Hulett, Jay S.; Brady, Brian K.; Cunningham, Kevin M.

    2002-01-01

    A PEM fuel cell having electrical contact elements comprising a corrosion-susceptible substrate metal coated with an electrically conductive, corrosion-resistant polymer containing a plurality of electrically conductive, corrosion-resistant filler particles. The substrate may have an oxidizable metal first layer (e.g., stainless steel) underlying the polymer coating.

  10. Corrosion resistant PEM fuel cell

    DOEpatents

    Fronk, Matthew Howard; Borup, Rodney Lynn; Hulett, Jay S.; Brady, Brian K. NY); Cunningham, Kevin M.

    2011-06-07

    A PEM fuel cell having electrical contact elements comprising a corrosion-susceptible substrate metal coated with an electrically conductive, corrosion-resistant polymer containing a plurality of electrically conductive, corrosion-resistant filler particles. The substrate may have an oxidizable metal first layer (e.g., stainless steel) underlying the polymer coating.

  11. Pattern prediction in EUV resists

    NASA Astrophysics Data System (ADS)

    Biafore, John J.; Smith, Mark D.; Wallow, Tom; Nalleau, Patrick; Blankenship, David; Deng, Yunfei

    2009-12-01

    Accurate and flexible simulation methods may be used to further a researcher's understanding of how complex resist effects influence the patterning of critical structures. In this work, we attempt to gain insight into the behavior of a state-of-the-art EUV resist through the use of stochastic resist modeling. The statistics of photon and molecule counting are discussed. The acid generation mechanism at EUV is discussed. At lambda = 13.5 nm, the acid generation mechanism may be similar to that found in electron beam resists: acid generators are hypothesized to be activated by secondary electrons yielded by ionization of the resist matrix by high-energy EUV photons, suggesting that acid generators may be activated some distance from the absorption site. A discrete, probabilistic ionization and electron scattering model for PAG conversion at EUV is discussed. The simulated effect of resist absorbance at EUV upon doseto- size and line-width roughness is shown. The model's parameterized fit to experimental data from a resist irradiated EUV are shown. Predictions of statistical resist responses such as CD distribution and line-width roughness are compared with experimental data.

  12. ANTIMICROBIAL RESISTANCE TRENDS IN SALMONELLA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Since the early 1990’s there has been increasing awareness and concern regarding the development of antimicrobial resistance among bacteria of public health significance. Reports targeting zoonotic bacteria, and in particular Salmonella species, suggest that resistance is trending upwar...

  13. Biofilm-specific antibiotic resistance.

    PubMed

    Mah, Thien-Fah

    2012-09-01

    Bacterial biofilms are the basis of many persistent diseases. The persistence of these infections is primarily attributed to the increased antibiotic resistance exhibited by the cells within the biofilms. This resistance is multifactorial; there are multiple mechanisms of resistance that act together in order to provide an increased overall level of resistance to the biofilm. These mechanisms are based on the function of wild-type genes and are not the result of mutations. This article reviews the known mechanisms of resistance, including the ability of the biofilm matrix to prevent antibiotics from reaching the cells and the function of individual genes that are preferentially expressed in biofilms. Evidence suggests that these mechanisms have been developed as a general stress response of biofilms that enables the cells in the biofilm to respond to all of the changes in the environment that they may encounter. PMID:22953707

  14. Heat resistant protective hand covering

    NASA Technical Reports Server (NTRS)

    Sidman, K. R.; Arons, I. J. (Inventor)

    1984-01-01

    The heat resistant, protective glove is made up of first and second shell sections which define a palm side and a backside, respectively. The first shell section is made of a twill wave fabric of a temperature-resistant aromatic polyamide fiber. The second shell section is made of a knitted fabric of a temperature-resistant aromatic polyamide fiber. The first and second shell sections are secured to one another, e.g., by sewing, to provide the desired glove configuration and an opening for insertion of the wearer's hand. The protective glove also includes a first liner section which is secured to and overlies the inner surface of the first shell section and is made of a felt fabric of a temperature-resistant aromatic polyamide fiber and has a flame resistant, elastomenic coating on the surface facing and overlying the inner surface of the first shell section.

  15. Variable resistance training promotes greater fatigue resistance but not hypertrophy versus constant resistance training.

    PubMed

    Walker, Simon; Hulmi, Juha J; Wernbom, Mathias; Nyman, Kai; Kraemer, William J; Ahtiainen, Juha P; Häkkinen, Keijo

    2013-09-01

    Loading using variable resistance devices, where the external resistance changes in line with the force:angle relationship, has been shown to cause greater acute neuromuscular fatigue and larger serum hormone responses. This may indicate a greater potential for adaptation during long-term training. Twelve (constant resistance group) and 11 (variable resistance group) men completed 20 weeks of resistance training with 10 men as non-training controls. Training-induced adaptations were assessed by bilateral leg press one repetition maximum, a repetition to failure test using 75 % 1RM, lower limb lean mass and vastus lateralis cross-sectional area. Only the variable resistance training group improved the total number of repetitions (41 ± 46 %) and volume load (52 ± 37 %) during the repetition to failure test (P < 0.05). Similar improvements in maximum strength and hypertrophy of the lower limbs were observed in both training groups. Also, constant and variable resistance 5 × 10RM leg press loadings were performed before and after training in a crossover design. Acute loading-induced responses were assessed by concentric and isometric force, serum hormone concentrations and phosphorylation of intramuscular signalling proteins (0-30 min post-loading). Greater acute decreases in force (P < 0.05-0.01), and greater increases in serum testosterone and cortisol concentration (P < 0.05) and ERK 1/2 phosphorylation (P < 0.05) were observed following variable resistance loadings before and after training. Greater training-induced improvements in fatigue resistance occurred in the variable resistance training group, which may be due to greater acute fatigue and physiological responses during variable versus constant resistance loadings. PMID:23636698

  16. Paraquat Resistance in Conyza1

    PubMed Central

    Fuerst, E. Patrick; Nakatani, Herbert Y.; Dodge, Alan D.; Penner, Donald; Arntzen, Charles J.

    1985-01-01

    A biotype of Conyza bonariensis (L.) Cronq. (identical to Conyza linefolia in other publications) originating in Egypt is resistant to the herbicide 1,1′-dimethyl-4,4′-bipyridinium ion (paraquat). Penetration of the cuticle by [14C]paraquat was greater in the resistant biotype than the susceptible (wild) biotype; therefore, resistance was not due to differences in uptake. The resistant and susceptible biotypes were indistinguishable by measuring in vitro photosystem I partial reactions using paraquat, 6,7-dihydrodipyrido [1,2-α:2′,1′-c] pyrazinediium ion (diquat), or 7,8-dihydro-6H-dipyrido [1,2-α:2′,1′-c] [1,4] diazepinediium ion (triquat) as electron acceptors. Therefore, alteration at the electron acceptor level of photosystem I is not the basis for resistance. Chlorophyll fluorescence measured in vivo was quenched in the susceptible biotype by leaf treatment with the bipyridinium herbicides. Resistance to quenching of in vivo chlorophyll fluorescence was observed in the resistant biotype, indicating that the herbicide was excluded from the chloroplasts. Movement of [14C] paraquat was restricted in the resistant biotype when excised leaves were supplied [14C]paraquat through the petiole. We propose that the mechanism of resistance to paraquat is exclusion of paraquat from its site of action in the chloroplast by a rapid sequestration mechanism. No differential binding of paraquat to cell walls isolated from susceptible and resistant biotypes could be detected. The exact site and mechanism of paraquat binding to sequester the herbicide remains to be determined. Images Fig. 6 PMID:16664176

  17. Electrically Variable Resistive Memory Devices

    NASA Technical Reports Server (NTRS)

    Liu, Shangqing; Wu, Nai-Juan; Ignatiev, Alex; Charlson, E. J.

    2010-01-01

    Nonvolatile electronic memory devices that store data in the form of electrical- resistance values, and memory circuits based on such devices, have been invented. These devices and circuits exploit an electrically-variable-resistance phenomenon that occurs in thin films of certain oxides that exhibit the colossal magnetoresistive (CMR) effect. It is worth emphasizing that, as stated in the immediately preceding article, these devices function at room temperature and do not depend on externally applied magnetic fields. A device of this type is basically a thin film resistor: it consists of a thin film of a CMR material located between, and in contact with, two electrical conductors. The application of a short-duration, low-voltage current pulse via the terminals changes the electrical resistance of the film. The amount of the change in resistance depends on the size of the pulse. The direction of change (increase or decrease of resistance) depends on the polarity of the pulse. Hence, a datum can be written (or a prior datum overwritten) in the memory device by applying a pulse of size and polarity tailored to set the resistance at a value that represents a specific numerical value. To read the datum, one applies a smaller pulse - one that is large enough to enable accurate measurement of resistance, but small enough so as not to change the resistance. In writing, the resistance can be set to any value within the dynamic range of the CMR film. Typically, the value would be one of several discrete resistance values that represent logic levels or digits. Because the number of levels can exceed 2, a memory device of this type is not limited to binary data. Like other memory devices, devices of this type can be incorporated into a memory integrated circuit by laying them out on a substrate in rows and columns, along with row and column conductors for electrically addressing them individually or collectively.

  18. Understanding Resistance and At-Risk Students.

    ERIC Educational Resources Information Center

    Field, James C.; Olafson, Lori J.

    1999-01-01

    Describes an ongoing study of students becoming resistant in middle school. The study aims to identify conditions that give rise to student resistance, uncover how resistance develops, describe kinds and forms of resistance, and find out what resistance means from the viewpoints of students, teachers, and parents. (SLD)

  19. Best management practices for herbicide resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In spite of the recent focus on herbicide resistant weeds, herbicide resistant weeds are not new to agriculture; the first herbicide resistant weed was documented in 1957, with the first widespread resistance occurring in common groundsel with atrazine in the early 1970’s. Glyphosate resistant weed...

  20. Resistive instabilities in tokamaks

    SciTech Connect

    Rutherford, P.H.

    1985-10-01

    Low-m tearing modes constitute the dominant instability problem in present-day tokamaks. In this lecture, the stability criteria for representative current profiles with q(0)-values slightly less than unit are reviewed; ''sawtooth'' reconnection to q(0)-values just at, or slightly exceeding, unity is generally destabilizing to the m = 2, n = 1 and m = 3, n = 2 modes, and severely limits the range of stable profile shapes. Feedback stabilization of m greater than or equal to 2 modes by rf heating or current drive, applied locally at the magnetic islands, appears feasible; feedback by island current drive is much more efficient, in terms of the radio-frequency power required, then feedback by island heating. Feedback stabilization of the m = 1 mode - although yielding particularly beneficial effects for resistive-tearing and high-beta stability by allowing q(0)-values substantially below unity - is more problematical, unless the m = 1 ideal-MHD mode can be made positively stable by strong triangular shaping of the central flux surfaces. Feedback techniques require a detectable, rotating MHD-like signal; the slowing of mode rotation - or the excitation of non-rotating modes - by an imperfectly conducting wall is also discussed.

  1. Creep Resistant Zinc Alloy

    SciTech Connect

    Frank E. Goodwin

    2002-12-31

    This report covers the development of Hot Chamber Die Castable Zinc Alloys with High Creep Strengths. This project commenced in 2000, with the primary objective of developing a hot chamber zinc die-casting alloy, capable of satisfactory service at 140 C. The core objectives of the development program were to: (1) fill in missing alloy data areas and develop a more complete empirical model of the influence of alloy composition on creep strength and other selected properties, and (2) based on the results from this model, examine promising alloy composition areas, for further development and for meeting the property combination targets, with the view to designing an optimized alloy composition. The target properties identified by ILZRO for an improved creep resistant zinc die-casting alloy were identified as follows: (1) temperature capability of 1470 C; (2) creep stress of 31 MPa (4500 psi); (3) exposure time of 1000 hours; and (4) maximum creep elongation under these conditions of 1%. The project was broadly divided into three tasks: (1) Task 1--General and Modeling, covering Experimental design of a first batch of alloys, alloy preparation and characterization. (2) Task 2--Refinement and Optimization, covering Experimental design of a second batch of alloys. (3) Task 3--Creep Testing and Technology transfer, covering the finalization of testing and the transfer of technology to the Zinc industry should have at least one improved alloy result from this work.

  2. Multilevel Resistance Programming in Conductive Bridge Resistive Memory

    NASA Astrophysics Data System (ADS)

    Mahalanabis, Debayan

    This work focuses on the existence of multiple resistance states in a type of emerging non-volatile resistive memory device known commonly as Programmable Metallization Cell (PMC) or Conductive Bridge Random Access Memory (CBRAM), which can be important for applications such as multi-bit memory as well as non-volatile logic and neuromorphic computing. First, experimental data from small signal, quasi-static and pulsed mode electrical characterization of such devices are presented which clearly demonstrate the inherent multi-level resistance programmability property in CBRAM devices. A physics based analytical CBRAM compact model is then presented which simulates the ion-transport dynamics and filamentary growth mechanism that causes resistance change in such devices. Simulation results from the model are fitted to experimental dynamic resistance switching characteristics. The model designed using Verilog-a language is computation-efficient and can be integrated with industry standard circuit simulation tools for design and analysis of hybrid circuits involving both CMOS and CBRAM devices. Three main circuit applications for CBRAM devices are explored in this work. Firstly, the susceptibility of CBRAM memory arrays to single event induced upsets is analyzed via compact model simulation and experimental heavy ion testing data that show possibility of both high resistance to low resistance and low resistance to high resistance transitions due to ion strikes. Next, a non-volatile sense amplifier based flip-flop architecture is proposed which can help make leakage power consumption negligible by allowing complete shutdown of power supply while retaining its output data in CBRAM devices. Reliability and energy consumption of the flip-flop circuit for different CBRAM low resistance levels and supply voltage values are analyzed and compared to CMOS designs. Possible extension of this architecture for threshold logic function computation using the CBRAM devices as re

  3. Drug resistance in castration resistant prostate cancer: resistance mechanisms and emerging treatment strategies

    PubMed Central

    Armstrong, Cameron M; Gao, Allen C

    2015-01-01

    Several mechanisms facilitate the progression of hormone-sensitive prostate cancer to castration-resistant prostate cancer (CRPC). At present, the approved chemotherapies for CRPC include systemic drugs (docetaxel and cabazitaxel) and agents that target androgen signaling, including enzalutamide and abiraterone. While up to 30% of patients have primary resistance to these treatments, each of these drugs confers a significant survival benefit for many. Over time, however, all patients inevitably develop resistance to treatment and their disease will continue to progress. Several key mechanisms have been identified that give rise to drug resistance. Expression of constitutively active variants of the androgen receptor, such as AR-V7, intracrine androgens and overexpression of androgen synthesis enzymes like AKR1C3, and increased drug efflux through ABCB1 are just some of the many discovered mechanisms of drug resistance. Treatment strategies are being developed to target these pathways and reintroduce drug sensitivity. Niclosamide has been discovered to reduce AR-V7 activity and synergized to enzalutamide. Indomethacin has been explored to inhibit AKR1C3 activity and showed to be able to reverse resistance to enzalutamide. ABCB1 transport activity can be mitigated by the phytochemical apigenin and by antiandrogens such as bicalutamide, with each improving cellular response to chemotherapeutics. By better understanding the mechanisms by which drug resistance develops improved treatment strategies will be made possible. Herein, we review the existing knowledge of CRPC therapies and resistance mechanisms as well as methods that have been identified which may improve drug sensitivity. PMID:26309896

  4. Herbicide-Resistant: Toward an understanding of resistance development and the impact of herbicide resistant crops

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For the past half century, herbicides have been the principal means of economic weed management in commercial crops in the US. Although weed resistance to herbicides was anticipated, weeds with resistance to herbicides did not appear until over 20 years after the initiation of herbicide use. Weed co...

  5. Resistance thermometer has linear resistance-temperature coefficient at low temperatures

    NASA Technical Reports Server (NTRS)

    Kuzyk, W.

    1966-01-01

    Resistance thermometer incorporating a germanium resistance element with a platinum resistance element in a wheatstone bridge circuit has a linear temperature-resistance coefficient over a range from approximately minus 140 deg C to approximately minus 253 deg C.

  6. Antibiotic resistance in probiotic bacteria

    PubMed Central

    Gueimonde, Miguel; Sánchez, Borja; G. de los Reyes-Gavilán, Clara; Margolles, Abelardo

    2013-01-01

    Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. The main probiotic bacteria are strains belonging to the genera Lactobacillus and Bifidobacterium, although other representatives, such as Bacillus or Escherichia coli strains, have also been used. Lactobacillus and Bifidobacterium are two common inhabitants of the human intestinal microbiota. Also, some species are used in food fermentation processes as starters, or as adjunct cultures in the food industry. With some exceptions, antibiotic resistance in these beneficial microbes does not constitute a safety concern in itself, when mutations or intrinsic resistance mechanisms are responsible for the resistance phenotype. In fact, some probiotic strains with intrinsic antibiotic resistance could be useful for restoring the gut microbiota after antibiotic treatment. However, specific antibiotic resistance determinants carried on mobile genetic elements, such as tetracycline resistance genes, are often detected in the typical probiotic genera, and constitute a reservoir of resistance for potential food or gut pathogens, thus representing a serious safety issue. PMID:23882264

  7. Antibiotic resistance in Burkholderia species.

    PubMed

    Rhodes, Katherine A; Schweizer, Herbert P

    2016-09-01

    The genus Burkholderia comprises metabolically diverse and adaptable Gram-negative bacteria, which thrive in often adversarial environments. A few members of the genus are prominent opportunistic pathogens. These include Burkholderia mallei and Burkholderia pseudomallei of the B. pseudomallei complex, which cause glanders and melioidosis, respectively. Burkholderia cenocepacia, Burkholderia multivorans, and Burkholderia vietnamiensis belong to the Burkholderia cepacia complex and affect mostly cystic fibrosis patients. Infections caused by these bacteria are difficult to treat because of significant antibiotic resistance. The first line of defense against antimicrobials in Burkholderia species is the outer membrane penetration barrier. Most Burkholderia contain a modified lipopolysaccharide that causes intrinsic polymyxin resistance. Contributing to reduced drug penetration are restrictive porin proteins. Efflux pumps of the resistance nodulation cell division family are major players in Burkholderia multidrug resistance. Third and fourth generation β-lactam antibiotics are seminal for treatment of Burkholderia infections, but therapeutic efficacy is compromised by expression of several β-lactamases and ceftazidime target mutations. Altered DNA gyrase and dihydrofolate reductase targets cause fluoroquinolone and trimethoprim resistance, respectively. Although antibiotic resistance hampers therapy of Burkholderia infections, the characterization of resistance mechanisms lags behind other non-enteric Gram-negative pathogens, especially ESKAPE bacteria such as Acinetobacter baumannii, Klebsiella pneumoniae and Pseudomonas aeruginosa. PMID:27620956

  8. Macrolide resistance in Streptococcus species

    PubMed Central

    Ilakkiya, A.; Parveen, Shabana; Kumar, C. Naveen; Swathi, S.

    2015-01-01

    Background: The Streptococci are Gram-positive spherical bacteria (cocci) that characteristically form pairs and chains during growth. Some macrolide-resistant bacteria lack the proper receptor on the ribosome (through methylation of the rRNA). This may be under plasmid or chromosomal control. Aim and Objectives: The aim was to study the prevalence of macrolide resistance among the isolate and evaluate the degree of resistance by minimum inhibitory concentration (MIC) method. And also to detect the phenotypic pattern of macrolide resistance. Materials and Methods: All age group attending general medicine OPD and pediatric OPD with symptoms of respiratory and pyogenic infections are included in the study. Various samples are collected with detailed case history and processed for macrolide resistance among beta hemolytic Streptococci MIC method and D-test. Results: According to our studies resistance pattern in Group A Streptococci by D-test, cMLS was 27.85%, iMLS was 13.92%, M-type was 55.69%, in GCS, cMLS was 17.6%, M-type was 82.35% In GGS, cMLS was 31.58%, iMLS was 10.53% and M-type was 57.89%. Conclusions: Therefore by this study, we would like to highlight the necessity to do antibiotic sensitivity testing for all isolates, and limit the usage of antibiotics, whenever necessary and select the appropriate antibiotics for resistant strains. PMID:26015727

  9. Current perspectives on glycopeptide resistance.

    PubMed Central

    Woodford, N; Johnson, A P; Morrison, D; Speller, D C

    1995-01-01

    In the last 5 years, clinical isolates of gram-positive bacteria with intrinsic or acquired resistance to glycopeptide antibiotics have been encountered increasingly. In many of these isolates, resistance arises from an alteration of the antibiotic target site, with the terminal D-alanyl-D-alanine moiety of peptidoglycan precursors being replaced by groups that do not bind glycopeptides. Although the criteria for defining resistance have been revised frequently, the reliable detection of low-level glycopeptide resistance remains problematic and is influenced by the method chosen. Glycopeptide-resistant enterococci have emerged as a particular problem in hospitals, where in addition to sporadic cases, clusters of infections with evidence of interpatient spread have occurred. Studies using molecular typing methods have implicated colonization of patients, staff carriage, and environmental contamination in the dissemination of these bacteria. Choice of antimicrobial therapy for infections caused by glycopeptide-resistant bacteria may be complicated by resistance to other antibiotics. Severe therapeutic difficulties are being encountered among patients infected with enterococci, with some infections being untreatable with currently available antibiotics. PMID:8665471

  10. Antimicrobial resistance: a global response.

    PubMed Central

    Smith, Richard D.; Coast, Joanna

    2002-01-01

    Resistance to antimicrobial therapies reduces the effectiveness of these drugs, leading to increased morbidity, mortality, and health care expenditure. Because globalization increases the vulnerability of any country to diseases occurring in other countries, resistance presents a major threat to global public health, and no country acting on its own can adequately protect the health of its population against it. International collective action is therefore essential. Nevertheless, responsibility for health remains predominantly national. Consequently, there is a potentially significant disparity between the problems and solutions related to antimicrobial resistance and the institutions and mechanisms that are available to deal with them. This paper considers the capacity of national and international institutions and mechanisms to generate a collective response to antimicrobial resistance. Strategies for containing resistance are outlined, with particular reference to globally coordinated activities of countries. The adequacy of national and international responses to resistance is assessed, and the actions that international bodies could take to solve difficulties associated with present responses are highlighted. Approaches are suggested for securing international collective action for the containment of antimicrobial resistance. PMID:11953791

  11. Drug resistance in Giardia duodenalis.

    PubMed

    Ansell, Brendan R E; McConville, Malcolm J; Ma'ayeh, Showgy Y; Dagley, Michael J; Gasser, Robin B; Svärd, Staffan G; Jex, Aaron R

    2015-11-01

    Giardia duodenalis is a microaerophilic parasite of the human gastrointestinal tract and a major contributor to diarrheal and post-infectious chronic gastrointestinal disease world-wide. Treatment of G. duodenalis infection currently relies on a small number of drug classes. Nitroheterocyclics, in particular metronidazole, have represented the front line treatment for the last 40 years. Nitroheterocyclic-resistant G. duodenalis have been isolated from patients and created in vitro, prompting considerable research into the biomolecular mechanisms of resistance. These compounds are redox-active and are believed to damage proteins and DNA after being activated by oxidoreductase enzymes in metabolically active cells. In this review, we explore the molecular phenotypes of nitroheterocyclic-resistant G. duodenalis described to date in the context of the protist's unusual glycolytic and antioxidant systems. We propose that resistance mechanisms are likely to extend well beyond currently described resistance-associated enzymes (i.e., pyruvate ferredoxin oxidoreductases and nitroreductases), to include NAD(P)H- and flavin-generating pathways, and possibly redox-sensitive epigenetic regulation. Mechanisms that allow G. duodenalis to tolerate oxidative stress may lead to resistance against both oxygen and nitroheterocyclics, with implications for clinical control. The present review highlights the potential for systems biology tools and advanced bioinformatics to further investigate the multifaceted mechanisms of nitroheterocyclic resistance in this important pathogen. PMID:25922317

  12. Glyphosate resistance: state of knowledge

    PubMed Central

    Sammons, Robert Douglas; Gaines, Todd A

    2014-01-01

    Studies of mechanisms of resistance to glyphosate have increased current understanding of herbicide resistance mechanisms. Thus far, single-codon non-synonymous mutations of EPSPS (5-enolypyruvylshikimate-3-phosphate synthase) have been rare and, relative to other herbicide mode of action target-site mutations, unconventionally weak in magnitude for resistance to glyphosate. However, it is possible that weeds will emerge with non-synonymous mutations of two codons of EPSPS to produce an enzyme endowing greater resistance to glyphosate. Today, target-gene duplication is a common glyphosate resistance mechanism and could become a fundamental process for developing any resistance trait. Based on competition and substrate selectivity studies in several species, rapid vacuole sequestration of glyphosate occurs via a transporter mechanism. Conversely, as the chloroplast requires transporters for uptake of important metabolites, transporters associated with the two plastid membranes may separately, or together, successfully block glyphosate delivery. A model based on finite glyphosate dose and limiting time required for chloroplast loading sets the stage for understanding how uniquely different mechanisms can contribute to overall glyphosate resistance. PMID:25180399

  13. Corrosion resistant pipe with extremely high impact resistance

    SciTech Connect

    Drake, S.

    1999-11-01

    The next generation of fiberglass pipe, which combines outstanding corrosion resistance to an extremely wide range of industrial chemicals with impact resistance more than 100 times better than existing fiberglass pipe, is introduced. This pipe is initially rated for operating pressures of 150 psi (10 Bar) at up to 225 F (107 C), and has corrosion resistance that generally is as good or better than traditional vinyl ester or epoxy resins. Its resistance to halogens such as chlorine and bromine is especially outstanding. These properties are achieved with the use of a new type of DUCTILE thermosetting resin. Included is a discussion of the resin system and data comparing the properties of this new piping system with traditional epoxy and vinyl ester piping.

  14. Antimicrobial (Drug) Resistance: Methicillin-Resistant Staphylococcus aureus (MRSA)

    MedlinePlus

    ... NIAID invests in basic research to understand the biology of microbes, their behavior, and how drug resistance ... Nucleotide Polymorphism Phylogenetics & Ontology Proteomics & Protein Analysis Systems Biology Data Portals Software Applications BCBB Mobyle Interface Designer ( ...

  15. Postiive tone resists based on network deploymerization of molecular resists

    NASA Astrophysics Data System (ADS)

    Lawson, Richard A.; Cheng, Jing; Cheshmehkani, Ameneh; Tolbert, Laren M.; Henderson, Clifford L.

    2013-03-01

    Conventional chemically amplified resists have several issues that can potentially limit their capability for sub-40 nm imaging. One of the major issues at this size scale is that the mechanical strength of positive tone CARs limits the amount of stress they can withstand during development, rinse, and drying, thus leading to problems with pattern collapse due to the high capillary forces generated during drying. This problem is exasperated by the fact that linear polymers show dramatically reduced modulus at sub-50 nm features sizes. To improve on this problem, we have made a positive tone resist based on network depolymerization of molecular resists. The resist thermally cross-links after being spin cast into thin film form through reactions between vinyl ether groups and carboxylic acid groups. By cross-linking the resist to form a dense three dimensional polymer network, the mechanical strength of the resist is greatly improved compared to linear polymers. The network is depolymerized using an acid catalyzed reaction to create development contrast that allows for patterning of the resist via development in either aqueous base or organic solvent. One drawback of the current resist design is that the free carboxylic acids on the resist molecule appear to react in solution at room temperature with both the vinyl ether groups on adjacent molecules and with any added base quencher. These reactions cause reduced effectiveness of the base quencher and produce a noticeable resist shelf life problem. Despite these limitations, the material was used to compare the effect of development in aqueous base versus organic solvent. The resist formulated in this work showed a DUV sensitivity of 7 mJ/cm2 and a contrast of 5.2 for development in either solvent or aqueous base. Under 100 keV e-beam imaging, the material showed 40 nm resolution for both development types. In standard 0.26 N TMAH, the dose-to-size was 84 μC/cm2 with 3σ LER of 14.2 nm. Using methyl isobutyl ketone

  16. Resistance Measurements on Play-Doh.

    ERIC Educational Resources Information Center

    Jones, Brian

    1993-01-01

    Presents a laboratory exercise to reinforce the concepts of conductivity and resistance. Students measure resistance over rolled out Play-Doh of differing lengths and widths using the four-point resistance measurement method. (MDH)

  17. Radiation resistance of acinetobacter spp.

    NASA Astrophysics Data System (ADS)

    Whitby, James L.

    1995-02-01

    The radiation resistance of 78 different strains of Acinetobacter sp. 42 from clinical isolates and 36 from other sources were compared with 15 clinical isolates and 12 other strains from Denmark. None of the Canadian strains was as resistant as resistant-enhanced Danish strains. Four strains had D 10 values of 3.1-3.6 kGy. Irradiated and unirradiated cells from all strains grew well, when cultured in Trypticase-Soy Broth at 30°C. Most cultures grew after overnight incubation. It was concluded that there would be no difficulty in detecting these strains, using ISO methodology for establishing the radiation sterilization dose for devices.

  18. Jam-resistant speech encoding

    NASA Astrophysics Data System (ADS)

    Poole, M. A.; Rifkin, R.

    1983-06-01

    This report describes techniques that provide increased jam resistance for digitized speech. Methods for increasing the jam resistance of pulse code modulated data are analyzed and evaluated in listener tests. Special emphasis is placed on new voice encoding approaches that take advantage of a spread spectrum system with a variable (or multiple)-data-rate/variable (or multiple)-AJ capability. Methods for matching a source to a channel in a jamming environment are investigated. Several techniques that provide about a 4 dB increase in jam resistance have been identified.

  19. Fire Resistant, Moisture Barrier Membrane

    NASA Technical Reports Server (NTRS)

    St.Clair, Terry L. (Inventor)

    2000-01-01

    A waterproof and breathable, fire-resistant laminate is provided for use in tents, garments, shoes, and covers, especially in industrial, military and emergency situations. The laminate permits water vapor evaporation while simultaneously preventing liquid water penetration. Further, the laminate is fire-resistant and significantly reduces the danger of toxic compound production when exposed to flame or other high heat source. The laminate may be applied to a variety of substrates and is comprised of a silicone rubber and plurality of fire-resistant, inherently thermally-stable polyimide particles.

  20. Fire Resistant, Moisture Barrier Membrane

    NASA Technical Reports Server (NTRS)

    St.Clair, Terry L. (Inventor)

    1998-01-01

    A waterproof and breathable, fire-resistant laminate is provided for use in tents, garments, shoes, and covers, especially in industrial, military and emergency situations. The laminate permits water vapor evaporation while simultaneously preventing liquid water penetration. Further, the laminate is fire-resistant and significantly reduces the danger of toxic compound production when exposed to flame or other high heat source. The laminate may be applied to a variety of substrates and is comprised of a silicone rubber and plurality of fire-resistant, inherently thermally-stable polyimide particles.

  1. [Resistance to the antimalarial drugs].

    PubMed

    Venanzi, E; López-Vélez, R

    2016-09-01

    Malaria is one of the most widespread infectious diseases around the world with 214 million cases and 438,000 deaths in 2015. In the early twentieth century it was described for the first time the resistance to quinine and, since then, drug resistance to antimalarial drugs has spread up to represent a global challenge in the fight and control of malaria. Understanding the mechanisms, geography and monitoring tools that we can act against resistance to antimalarial drugs is critical to prevent its expansion. PMID:27608319

  2. Interconnect resistance of photovoltaic submodules

    NASA Technical Reports Server (NTRS)

    Volltrauer, H.; Eser, E.; Delahoy, A. E.

    1985-01-01

    Small area amorphous silicon solar cells generally have higher efficiencies than large interconnected submodules. Among the reasons for the differences in performance are the lack of large area uniformity, the effect of nonzero tin oxide sheet resistance, and possibly pinholes in the various layers. Another and usually small effect that can contribute to reduced performance of interconnected cells is the resistance of the interconnection i.e., the series resistance introduced by the metal to tin oxide contact through silicon. Proper processing problems to avoid poor contacts are discussed.

  3. Resistant and Refractory Hypertension: Antihypertensive Treatment Resistance vs Treatment Failure.

    PubMed

    Siddiqui, Mohammed; Dudenbostel, Tanja; Calhoun, David A

    2016-05-01

    Resistant or difficult to treat hypertension is defined as high blood pressure that remains uncontrolled with 3 or more different antihypertensive medications, including a diuretic. Recent definitions also include controlled blood pressure with use of 4 or more medications as also being resistant to treatment. Recently, refractory hypertension, an extreme phenotype of antihypertensive treatment failure has been defined as hypertension uncontrolled with use of 5 or more antihypertensive agents, including a long-acting thiazide diuretic and a mineralocorticoid receptor antagonist. Patients with resistant vs refractory hypertension share similar characteristics and comorbidities, including obesity, African American race, female sex, diabetes, coronary heart disease, chronic kidney disease, and obstructive sleep apnea. Patients with refractory vs resistant hypertension tend to be younger and are more likely to have been diagnosed with congestive heart failure. Refractory hypertension might also differ from resistant hypertension in terms of underlying cause. Preliminary evidence suggests that refractory hypertension is more likely to be neurogenic in etiology (ie, heightened sympathetic tone), vs a volume-dependent hypertension that is more characteristic of resistant hypertension in general. PMID:26514749

  4. The multigap resistive plate chamber

    SciTech Connect

    Zeballos, E. Cerron; Crotty, I.; Hatzifotiadou, D.; Valverde, J. Lamas; Neupane, S.; Williams, M. C. S.; Zichichi, A.

    2015-02-03

    The paper describes the multigap resistive plate chamber (RPC). This is a variant of the wide gap RPC. However it has much improved time resolution, while keeping all the other advantages of the wide gap RPC design.

  5. Antimalarial drug resistance: An overview.

    PubMed

    Antony, Hiasindh Ashmi; Parija, Subhash Chandra

    2016-01-01

    Malaria is a major public health burden throughout the world. Resistance to the antimalarial drugs has increased the mortality and morbidity rate that is achieved so far through the malaria control program. Monitoring the drug resistance to the available antimalarial drugs helps to implement effective drug policy, through the in vivo efficacy studies, in vitro drug susceptibility tests and detection of molecular markers. It is important to understand the mechanism of the antimalarial drugs, as it is one of the key factors in the emergence and spread of drug resistance. This review summarizes the commonly used antimalarial drugs, their mechanism of action and the genetic markers validated so far for the detection of drug-resistant parasites. PMID:26998432

  6. Addressing viral resistance through vaccines

    PubMed Central

    Laughlin, Catherine; Schleif, Amanda; Heilman, Carole A

    2015-01-01

    Antimicrobial resistance is a serious healthcare concern affecting millions of people around the world. Antiviral resistance has been viewed as a lesser threat than antibiotic resistance, but it is important to consider approaches to address this growing issue. While vaccination is a logical strategy, and has been shown to be successful many times over, next generation viral vaccines with a specific goal of curbing antiviral resistance will need to clear several hurdles including vaccine design, evaluation and implementation. This article suggests that a new model of vaccination may need to be considered: rather than focusing on public health, this model would primarily target sectors of the population who are at high risk for complications from certain infections. PMID:26604979

  7. MURINE CYTOMEGALOVIRUS HOST RESISTANCE MODELS

    EPA Science Inventory

    Mouse cytomegalovirus (MCMV) is a well developed and extremely useful and relevant host resistance model for immunotoxicity testing. at cytomegalovirus (RCMV) is currently under development and may have similar applications. ytomegaloviruses are species specific; RCMV is a distin...

  8. Drug resistance in eukaryotic microorganisms.

    PubMed

    Fairlamb, Alan H; Gow, Neil A R; Matthews, Keith R; Waters, Andrew P

    2016-01-01

    Eukaryotic microbial pathogens are major contributors to illness and death globally. Although much of their impact can be controlled by drug therapy as with prokaryotic microorganisms, the emergence of drug resistance has threatened these treatment efforts. Here, we discuss the challenges posed by eukaryotic microbial pathogens and how these are similar to, or differ from, the challenges of prokaryotic antibiotic resistance. The therapies used for several major eukaryotic microorganisms are then detailed, and the mechanisms that they have evolved to overcome these therapies are described. The rapid emergence of resistance and the restricted pipeline of new drug therapies pose considerable risks to global health and are particularly acute in the developing world. Nonetheless, we detail how the integration of new technology, biological understanding, epidemiology and evolutionary analysis can help sustain existing therapies, anticipate the emergence of resistance or optimize the deployment of new therapies. PMID:27572976

  9. Strategies to Minimize Antibiotic Resistance

    PubMed Central

    Lee, Chang-Ro; Cho, Ill Hwan; Jeong, Byeong Chul; Lee, Sang Hee

    2013-01-01

    Antibiotic resistance can be reduced by using antibiotics prudently based on guidelines of antimicrobial stewardship programs (ASPs) and various data such as pharmacokinetic (PK) and pharmacodynamic (PD) properties of antibiotics, diagnostic testing, antimicrobial susceptibility testing (AST), clinical response, and effects on the microbiota, as well as by new antibiotic developments. The controlled use of antibiotics in food animals is another cornerstone among efforts to reduce antibiotic resistance. All major resistance-control strategies recommend education for patients, children (e.g., through schools and day care), the public, and relevant healthcare professionals (e.g., primary-care physicians, pharmacists, and medical students) regarding unique features of bacterial infections and antibiotics, prudent antibiotic prescribing as a positive construct, and personal hygiene (e.g., handwashing). The problem of antibiotic resistance can be minimized only by concerted efforts of all members of society for ensuring the continued efficiency of antibiotics. PMID:24036486

  10. Genetics Home Reference: warfarin resistance

    MedlinePlus

    ... it thins the blood, preventing blood clots from forming . Warfarin is often prescribed to prevent blood clots ... link) COUMARIN RESISTANCE Sources for This Page Azzam H, Elwakeel H, Awad I, El-Farahaty R, El- ...

  11. Resistance training and mitochondrial metabolism

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Objective: To determine if resistance exercise training improves skeletal muscle substrate oxidative capacity in older adults. Background: A decline in skeletal muscle oxidative capacity occurs with aging. Aerobic exercise increases skeletal muscle’s ability to oxidize multiple substrates. Th...

  12. Production of virus resistant plants

    DOEpatents

    Dougherty, W.G.; Lindbo, J.A.

    1996-12-10

    A method of suppressing virus gene expression in plants using untranslatable plus sense RNA is disclosed. The method is useful for the production of plants that are resistant to virus infection. 9 figs.

  13. How drug resistance takes shape

    PubMed Central

    Jeselsohn, Rinath

    2016-01-01

    Mutations in a hormone receptor can lead to therapeutic resistance by making it less able to bind and respond to hormone blocking drugs and by making it active, even when the hormome is not present. PMID:27010172

  14. Antibiotic resistance in pediatric urology

    PubMed Central

    Copp, Hillary L.

    2014-01-01

    Antibiotics are a mainstay in the treatment of bacterial infections, though their use is a primary risk factor for the development of antibiotic resistance. Antibiotic resistance is a growing problem in pediatric urology as demonstrated by increased uropathogen resistance. Lack of urine testing, nonselective use of prophylaxis, and poor empiric prescribing practices exacerbate this problem. This article reviews antibiotic utilization in pediatric urology with emphasis on modifiable practice patterns to potentially help mitigate the growing rates of antibiotic resistance. This includes urine testing to only treat when indicated and tailor broad-spectrum therapy as able; selective application of antibiotic prophylaxis to patients with high-grade vesicoureteral reflux and hydronephrosis with counseling regarding the importance of compliance; and using local antiobiograms, particularly pediatric-specific antiobiograms, with inpatient versus outpatient data. PMID:24688601

  15. Bacterial cheating limits antibiotic resistance

    NASA Astrophysics Data System (ADS)

    Xiao Chao, Hui; Yurtsev, Eugene; Datta, Manoshi; Artemova, Tanya; Gore, Jeff

    2012-02-01

    The widespread use of antibiotics has led to the evolution of resistance in bacteria. Bacteria can gain resistance to the antibiotic ampicillin by acquiring a plasmid carrying the gene beta-lactamase, which inactivates the antibiotic. This inactivation may represent a cooperative behavior, as the entire bacterial population benefits from removing the antibiotic. The cooperative nature of this growth suggests that a cheater strain---which does not contribute to breaking down the antibiotic---may be able to take advantage of cells cooperatively inactivating the antibiotic. Here we find experimentally that a ``sensitive'' bacterial strain lacking the plasmid conferring resistance can invade a population of resistant bacteria, even in antibiotic concentrations that should kill the sensitive strain. We observe stable coexistence between the two strains and find that a simple model successfully explains the behavior as a function of antibiotic concentration and cell density. We anticipate that our results will provide insight into the evolutionary origin of phenotypic diversity and cooperative behaviors.

  16. [Staphylococcus aureus and antibiotic resistance].

    PubMed

    Sancak, Banu

    2011-07-01

    After the report of first case of methicillin-resistant Staphylococcus aureus (MRSA) in 1961, MRSA become a major problem worldwide. Over the last decade MRSA strains have emerged as serious pathogens in nosocomial and community settings. Glycopeptides (vancomycin and teicoplanin) are still the current mainstay of therapy for infections caused by MRSA. In the last decade dramatic changes have occurred in the epidemiology of MRSA infections. The isolates with reduced susceptibility and in vitro resistance to vancomycin have emerged. Recently, therapeutic alternatives such as quinupristin/dalfopristin, linezolid, tigecycline and daptomycin have been introduced into clinical practice for treating MRSA infections. Nevertheless, these drugs are only approved for certain indication and resistance has already been reported. In this review, the new information on novel drugs for treating MRSA infections and the resistance mechanisms of these drugs were discussed. PMID:21935792

  17. (Mechanisms of tolerance and resistance)

    SciTech Connect

    Waters, L.C.

    1990-08-28

    The traveler participated in the Seventh International Congress of Pesticide Chemistry by presenting a poster entitled Studies on the Expression of Insecticide Resistance-Associated Cytochrome P450 in Drosophila Using Cloned DNA'' and as an invited speaker in the Workshop Session on Insecticide Resistance. The Congress covered a wide range of topics, including studies of new syntheic compounds and natural products with crop protecting properties, modes of action of pesticides, mechanisms of pesticide resistance, environmental fate of pesticides and estimates of risk to pesticide exposure. Several presentations on the potential role of cytochrome P450 in resistance to insecticides and herbicides were relevant to our work at ORNL's Biology Division on molecular mechanisms of P450 expression.

  18. Making Thermoplastics Flame-Resistant

    NASA Technical Reports Server (NTRS)

    Mueller, W. A.; Ingham, J. D.; Reilly, W. W.

    1984-01-01

    Inorganic hydrate-salt filler coated with elastomer containing acidic groups imparts flame and smoke retardancy to thermoplastics while preventing degradation of impact resistance that results from high filler loadings in thermoplastic.

  19. ac-resistance-measuring instrument

    SciTech Connect

    Hof, P.J.

    1981-04-22

    An auto-ranging ac resistance measuring instrument for remote measurement of the resistance of an electrical device or circuit connected to the instrument includes a signal generator which generates an ac excitation signal for application to a load, including the device and the transmission line, a monitoring circuit which provides a digitally encoded signal representing the voltage across the load, and a microprocessor which operates under program control to provide an auto-ranging function by which range resistance is connected in circuit with the load to limit the load voltage to an acceptable range for the instrument, and an auto-compensating function by which compensating capacitance is connected in shunt with the range resistance to compensate for the effects of line capacitance.

  20. "Feeling" Series and Parallel Resistances.

    ERIC Educational Resources Information Center

    Morse, Robert A.

    1993-01-01

    Equipped with drinking straws and stirring straws, a teacher can help students understand how resistances in electric circuits combine in series and in parallel. Follow-up suggestions are provided. (ZWH)

  1. Antimalarial drug resistance: An overview

    PubMed Central

    Antony, Hiasindh Ashmi; Parija, Subhash Chandra

    2016-01-01

    Malaria is a major public health burden throughout the world. Resistance to the antimalarial drugs has increased the mortality and morbidity rate that is achieved so far through the malaria control program. Monitoring the drug resistance to the available antimalarial drugs helps to implement effective drug policy, through the in vivo efficacy studies, in vitro drug susceptibility tests and detection of molecular markers. It is important to understand the mechanism of the antimalarial drugs, as it is one of the key factors in the emergence and spread of drug resistance. This review summarizes the commonly used antimalarial drugs, their mechanism of action and the genetic markers validated so far for the detection of drug-resistant parasites. PMID:26998432

  2. [Resistant hypertension : What is it?].

    PubMed

    Luft, F C

    2015-03-01

    When blood pressure is poorly controlled despite treatment with a diuretic and two antihypertensive drugs at adequate doses, the hypertension is termed resistant. The prevalence of resistant hypertension is increasing. Once pseudo-resistance due to poor compliance, secondary forms of hypertension, and massive salt consumption have been excluded, some authorities maintain that blood pressure can be invariably lowered using minoxidil or mineralocorticoid receptor blockade. I also adhered to this belief until we encountered a patient who despite treatment with seven antihypertensive agents, electrical carotid sinus stimulation, and catheter-based renal denervation continued to exhibit extraordinarily high blood pressure values. I am now convinced that resistant hypertension does indeed exist. The prevalence of such patients can be substantially reduced by means of a thorough history and physical examination, determining drug serum concentrations, and excluding secondary causes. PMID:25668441

  3. Erosion-resistant composite material

    DOEpatents

    Finch, C.B.; Tennery, V.J.; Curlee, R.M.

    A highly erosion-resistant composite material is formed of chemical vapor-deposited titanium diboride on a sintered titanium diboride-nickel substrate. This material may be suitable for use in cutting tools, coal liquefaction systems, etc.

  4. Calibration of platinum resistance thermometers.

    NASA Technical Reports Server (NTRS)

    Sinclair, D. H.; Terbeek, H. G.; Malone, J. H.

    1972-01-01

    Results of five years experience in calibrating about 1000 commercial platinum resistance thermometers (PRT) are reported. These PRT were relatively small and rugged, with ice-point resistances from 200 to 5000 ohms. Calibrations normalized in terms of resistance-difference ratios (Cragoe Z function) were found to be remarkably uniform for five of six different types of PRT tested, and to agree very closely with normalized calibrations of the primary reference standard type PRT. The Z function normalization cancels residual resistances which are not temperature dependent and simplifies interpolation between calibration points when the quality of a given type of PRT has been established in terms of uniform values of the Z function. Measurements at five or six well spaced base-point temperatures with Z interpolation will suffice to calibrate a PRT accurately from 4 to 900 K.

  5. Flame resistant elastic elastomeric fibers

    NASA Technical Reports Server (NTRS)

    Howarth, J. T.; Massucco, A. A.

    1972-01-01

    Development of materials to improve flame resistance of elastic elastomeric fibers is discussed. Two approaches, synthesis of polyether based urethanes and modification of synthesized urethanes with flame ratardant additives, are described. Specific applications of both techniques are presented.

  6. Making Graphene Resist Aggregation

    NASA Astrophysics Data System (ADS)

    Luo, Jiayan

    lose surface area. So their capacitive performance tends to decrease with increased loading level. But the crumpled balls can resist aggregation and retain high capacitance at high loading level. The crumpled graphene balls can be also used as expandable shells for wrapping lithium ion battery anode materials such as Si nanoparticles, which can accommodate their expansion/contraction without facture, and thus greatly improve the coulombic efficiency of the anode.

  7. [Nosocomial bacteria: profiles of resistance].

    PubMed

    Sow, A I

    2005-01-01

    Nosocomial infections may be parasitic, mycosal or viral, but bacterial infections are more frequent. They are transmitted by hands or by oral route. This paper describes the main bacteria responsive of nosocomial infections, dominated by Staphylococcus, enterobacteria and Pseudomonas aeruginosa. The author relates natural and savage profiles of these bacterias, characterized by multiresistance due to large use of antibiotics. Knowledge of natural resistance and verification of aquired resistance permit to well lead probabilist antibiotherapy. PMID:16190117

  8. Corrosion resistant neutron absorbing coatings

    SciTech Connect

    Choi, Jor-Shan; Farmer, Joseph C.; Lee, Chuck K.; Walker, Jeffrey; Russell, Paige; Kirkwood, Jon; Yang, Nancy; Champagne, Victor

    2012-05-29

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  9. Corrosion resistant neutron absorbing coatings

    SciTech Connect

    Choi, Jor-Shan; Farmer, Joseph C; Lee, Chuck K; Walker, Jeffrey; Russell, Paige; Kirkwood, Jon; Yang, Nancy; Champagne, Victor

    2013-11-12

    A method of forming a corrosion resistant neutron absorbing coating comprising the steps of spray or deposition or sputtering or welding processing to form a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material. Also a corrosion resistant neutron absorbing coating comprising a composite material made of a spray or deposition or sputtering or welding material, and a neutron absorbing material.

  10. Castable hot corrosion resistant alloy

    NASA Technical Reports Server (NTRS)

    Barrett, Charles A. (Inventor); Holt, William H. (Inventor)

    1988-01-01

    Some 10 wt percent nickel is added to an Fe-base alloy which has a ferrite microstructure to improve the high temperature castability and crack resistance while about 0.2 wt percent zirconium is added for improved high temperatur cyclic oxidation and corrosion resistance. The basic material is a high temperature FeCrAl heater alloy, and the addition provides a material suitable for burner rig nozzles.

  11. Nonconjugative Plasmids Encoding Sulfanilamide Resistance

    PubMed Central

    Mitsuhashi, Susumu; Inoue, Kunio; Inoue, Matsuhisa

    1977-01-01

    Nonconjugative plasmids encoding sulfanilamide (Sa) resistance were demonstrated at a high frequency in Shigella and Escherichia coli strains resistant to sulfanilamide. These Sa plasmids were all compatible with the standard plasmids used in compatibility testing. The sizes of seven Sa plasmids were measured by electron microscopy and ranged from 1.79 to 2.08 μm, corresponding to 3.5 to 3.9 megadaltons. Images PMID:334067

  12. Dealing with Resistance to Reform

    NASA Astrophysics Data System (ADS)

    Reif, Marc

    2008-09-01

    About the author: Any teacher, new or experienced, will at times face criticism, resistance, and even hostility from students, parents, and colleagues. An inexperienced teacher who runs a reformed classroom based on classroom discourse and "interactive engagement," both of which may run counter to school culture, risks resistance or even outright revolt. In this essay, which grew out of discussions on the Modeling Instruction Program Listserv, Marc Reif shares some strategies that can be used to forestall or deal with classroom opposition.

  13. Automated quantum Hall resistance standard

    SciTech Connect

    Schumacher, B.

    1994-12-31

    For precision quantized Hall resistance measurements quantum Hall effect samples have to be checked according to the CCE-guidelines. To perform these checks an automated measuring system is described, which is able to examine and characterize various samples. With these measurements a calibration of a precision 10 k{Omega} resistance standard is obtained with an uncertainty of better than 5 x 10{sup -8} (1 {sigma}) using a long-scale digital multimeter.

  14. Early diagnosis of resistant pathogens

    PubMed Central

    2013-01-01

    Infections with organisms that are resistant to various anti-microbial agents pose a serious challenge to effective management of infections. Resistance to antimicrobial agents, which may be intrinsic or acquired, has been noted in a wide variety of microorganisms causing human infections. These include resistance to antiviral agents in HIV, HBV, CMV and influenza virus, anti-parasitic agents in Plasmodium falciparum, anti-fungal agents in certain Candida species and MDR (multidrug-resistant) tuberculosis. It is however, the problem of multidrug-resistant bacterial infections (caused by MRSA, VRE, ESBL/AmpC/metallo-β lactamase producers and colistin-resistant Gram-negative bacilli) that has become a cause of major concern in clinical settings. Infections with these organisms can increase morbidity, mortality, increase the cost of therapy and increase the duration of hospitalization. The objective of this article is to review the question how early diagnosis of these infections, affects the overall management of infected or colonized patients, with regard to antimicrobial therapy. PMID:23302786

  15. [Vancomycin-resistant Staphylococcus aureus].

    PubMed

    Rodríguez, Carlos Andrés; Vesga, Omar

    2005-12-01

    The evolution and molecular mechanisms of vancomycin resistance in Staphylococcus aureus were reviewed. Case reports and research studies on biochemestry, electron microscopy and molecular biology of Staphylococcus aureus were selected from Medline database and summarized in the following review. After almost 40 years of successful treatment of S. aureus with vancomycin, several cases of clinical failures have been reported (since 1997). S. aureus strains have appeared with intermediate susceptibility (MIC 8-16 microg/ml), as well as strains with heterogeneous resistance (global MIC < or =4 microg/ml), but with subpopulations of intermediate susceptibility. In these cases, resistance is mediated by cell wall thickening with reduced cross linking. This traps the antibiotic before it reaches its major target, the murein monomers in the cell membrane. In 2002, a total vancomycin resistant strain (MIC > or =32 microg/ml) was reported with vanA genes from Enterococcus spp. These genes induce the change of D-Ala-D-Ala terminus for D-Ala-D-lactate in the cell wall precursors, leading to loss of affinity for glycopeptides. Vancomycin resistance in S. aureus has appeared; it is mediated by cell wall modifications that trap the antibiotic before it reaches its action site. In strains with total resistance, Enterococcus spp. genes have been acquired that lead to modification of the glycopeptide target. PMID:16433184

  16. Antimicrobial Resistance in Haemophilus influenzae

    PubMed Central

    Tristram, Stephen; Jacobs, Michael R.; Appelbaum, Peter C.

    2007-01-01

    Haemophilus influenzae is a major community-acquired pathogen causing significant morbidity and mortality worldwide. Meningitis and bacteremia due to type b strains occur in areas where the protein-conjugated type b vaccine is not in use, whereas nontypeable strains are major causes of otitis media, sinusitis, acute exacerbations of chronic bronchitis, and pneumonia. Antibiotic resistance in this organism is more diverse and widespread than is commonly appreciated. Intrinsic efflux resistance mechanisms limit the activity of the macrolides, azalides, and ketolides. β-Lactamase production is highly prevalent worldwide and is associated with resistance to ampicillin and amoxicillin. Strains with alterations in penicillin binding proteins, particularly PBP3 (β-lactamase negative ampicillin resistant and β-lactamase positive amoxicillin-clavulanate resistant), are increasing in prevalence, particularly in Japan, with increasing resistance to ampicillin, amoxicillin, amoxicillin-clavulanate, and many cephalosporins, limiting the efficacy of expanded-spectrum cephalosporins against meningitis and of many oral cephalosporins against other diseases. Most strains remain susceptible to the carbapenems, which are not affected by penicillin binding protein changes, and the quinolones. The activity of many oral agents is limited by pharmacokinetics achieved with administration by this route, and the susceptibility of isolates based on pharmacokinetic and pharmacodynamic parameters is reviewed. PMID:17428889

  17. Antimicrobial Resistance Mechanisms among Campylobacter

    PubMed Central

    2013-01-01

    Campylobacter jejuni and Campylobacter coli are recognized as the most common causative agents of bacterial gastroenteritis in the world. Humans most often become infected by ingesting contaminated food, especially undercooked chicken, but also other sources of bacteria have been described. Campylobacteriosis is normally a self-limiting disease. Antimicrobial treatment is needed only in patients with more severe disease and in those who are immunologically compromised. The most common antimicrobial agents used in the treatment of Campylobacter infections are macrolides, such as erythromycin, and fluoroquinolones, such as ciprofloxacin. Tetracyclines have been suggested as an alternative choice in the treatment of clinical campylobacteriosis but in practice are not often used. However, during the past few decades an increasing number of resistant Campylobacter isolates have developed resistance to fluoroquinolones and other antimicrobials such as macrolides, aminoglycosides, and beta-lactams. Trends in antimicrobial resistance have shown a clear correlation between use of antibiotics in the veterinary medicine and animal production and resistant isolates of Campylobacter in humans. In this review, the patterns of emerging resistance to the antimicrobial agents useful in treatment of the disease are presented and the mechanisms of resistance to these drugs in Campylobacter are discussed. PMID:23865047

  18. Multidrug Resistant and Extensively Drug Resistant Bacteria: A Study

    PubMed Central

    Basak, Silpi; Singh, Priyanka; Rajurkar, Monali

    2016-01-01

    Background and Objective. Antimicrobial resistance is now a major challenge to clinicians for treating patients. Hence, this short term study was undertaken to detect the incidence of multidrug-resistant (MDR), extensively drug-resistant (XDR), and pandrug-resistant (PDR) bacterial isolates in a tertiary care hospital. Material and Methods. The clinical samples were cultured and bacterial strains were identified in the department of microbiology. The antibiotic susceptibility profile of different bacterial isolates was studied to detect MDR, XDR, and PDR bacteria. Results. The antibiotic susceptibility profile of 1060 bacterial strains was studied. 393 (37.1%) bacterial strains were MDR, 146 (13.8%) strains were XDR, and no PDR was isolated. All (100%) Gram negative bacterial strains were sensitive to colistin whereas all (100%) Gram positive bacterial strains were sensitive to vancomycin. Conclusion. Close monitoring of MDR, XDR, or even PDR must be done by all clinical microbiology laboratories to implement effective measures to reduce the menace of antimicrobial resistance. PMID:26942013

  19. Insulin resistance and insulin sensitizers.

    PubMed

    Stumvoll, M; Häring, H

    2001-01-01

    Insulin resistance is a key factor in the pathogenesis of type 2 diabetes mellitus and a co-factor in the development of dyslipidaemia, hypertension and atherosclerosis. The causes of insulin resistance include factors such as obesity and physical inactivity, and there may also be genetic factors. The mechanism of obesity-related insulin resistance involves the release of factors from adipocytes which exert a negative effect on glucose metabolism: free fatty acids, tumour necrosis factor-alpha and the recently discovered hormone, resistin. The two resulting abnormalities observed consistently in glucose-intolerant states are impaired suppression of endogenous glucose production, and impaired stimulation of glucose uptake. Among the genetic factors, a polymorphism (Pro12Ala) in the peroxisome proliferator-activated receptor (PPAR) gamma is associated with a reduced risk of type 2 diabetes mellitus and increased insulin sensitivity, primarily that of lipolysis. On the other hand, the association with insulin resistance of a common polymorphism (Gly972Arg) in the insulin receptor substrate 1, long believed to be a plausible candidate gene, is weak at best. This polymorphism may instead be associated with reduced insulin secretion, which, in view of the recent recognition of the insulin signalling system in beta-cells, results in the development of a novel pathogenic concept. Finally, fine-mapping and positional cloning of the susceptibility locus on chromosome 2 resulted in the identification of a polymorphism (UCSNP-43 G/A) in the calpain-10 gene. In non-diabetic Pima Indians, this polymorphism was associated with insulin resistance of glucose disposal. The pharmacological treatment of insulin resistance has recently acquired a novel class of agents: the thiazolidinediones. They act through regulation of PPARgamma-dependent genes and probably interfere favourably with factors released from adipocytes which mediate obesity-associated insulin resistance. PMID:11684868

  20. Impact resistance of bar glasses.

    PubMed

    Shepherd, J P; Huggett, R H; Kidner, G

    1993-12-01

    Bar glasses are often used as weapons in interpersonal violence. Violence often erupts spontaneously and assailants use objects close to hand as weapons. After an initial national Accident and Emergency Department study to identify glass designs most often implicated in interpersonal violence, the impact resistance of 1-pint beer glasses was tested in a materials laboratory with a Zwick 5102 pendulum impact tester. Both straight-sided (nonik) glasses (annealed and tempered) and handled tankards (annealed) were tested to destruction. The impact resistance of new glasses was compared with that of glasses subjected to wear. The mean impact resistance of new annealed noniks did not differ significantly although new glasses were significantly more resistant than worn glasses (p < 0.01). It was not possible to break any of the tempered glasses with the pendulum used (maximum impact energy, 4 J). When noniks had been scratched at the rim to mimic wear, tempered glasses also had the highest impact resistance (p < 0.01) whereas the mean resistance of the annealed noniks was not significantly different. When tempered glasses failed during testing, they all disintegrated into relatively harmless cubes of glass, particularly the thicker bases of glasses. In contrast, annealed designs fractured leaving sharp shards although the thicker bases remained intact. The mean impact resistance of new annealed noniks was 0.5 J, of worn annealed noniks 0.08 J, of tempered new noniks > 4 J, of worn tempered noniks 0.18 J, and of tankards, 1.7 J.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8263994

  1. A New Mid-UV Resist With Oxygen Plasma Resistance

    NASA Astrophysics Data System (ADS)

    Liu, J. M.; Tzeng, Chao Huei

    1989-08-01

    A new silyl ether of resorcinol novolak resin (SERN) and a new photoactive compound (S-55NQ) have been developed for a bilayer resist system. The SERN resin is an addition-condensation type terpolymer from resorcinol, hexamethylenetetramine, and phenyl silyl ether (PSE), which is a reaction product of resorcinol and chlorosilane, under acid catalyzed condition. The S-55NQ sensitizer is a sulfonate ester of spiroglycol and naphthoquinone diazide. This alkaline soluble Si-containing resist, useful in the mid-UV region, shows high dry etching resistance to O2 plasma and O2 RIE. An etching rate ratio of 4.5 or higher based on HPR-204 as the bottom layer is obtained.

  2. Effect of nonsymmetrical flow resistance upon orifice impedance resistance

    NASA Technical Reports Server (NTRS)

    Posey, J. W.; Compton, K. J.

    1974-01-01

    A nonreactive orifice in an infinite baffle is analyzed. The pressure difference delta across the orifice varies sinusoidally with amplitude 1.0 and average value -P. The orifice resistance, delta p is discontinuous at zero velocity and exhibits the constant values R sub + and R sub - for u 0 and u 0, respectively. The resultant velocity has power in all harmonics of the excitation frequency. A quasi-linear resistance is defined and found to be relatively insensitive to the presence or absence of a resonant backing cavity; however, it does vary from 1.33 R sub + to 0.67 R sub + for a resistance ratio R sub +/R sub - between 0.5 and 2.0.

  3. Oxidation resistant alloys, method for producing oxidation resistant alloys

    DOEpatents

    Dunning, John S.; Alman, David E.

    2002-11-05

    A method for producing oxidation-resistant austenitic alloys for use at temperatures below 800 C. comprising of: providing an alloy comprising, by weight %: 14-18% chromium, 15-18% nickel, 1-3% manganese, 1-2% molybdenum, 2-4% silicon, 0% aluminum and the balance being iron; heating the alloy to 800 C. for between 175-250 hours prior to use in order to form a continuous silicon oxide film and another oxide film. The method provides a means of producing stainless steels with superior oxidation resistance at temperatures above 700 C. at a low cost

  4. Oxidation resistant alloys, method for producing oxidation resistant alloys

    DOEpatents

    Dunning, John S.; Alman, David E.

    2002-11-05

    A method for producing oxidation-resistant austenitic alloys for use at temperatures below 800.degree. C. comprising of: providing an alloy comprising, by weight %: 14-18% chromium, 15-18% nickel, 1-3% manganese, 1-2% molybdenum, 2-4% silicon, 0% aluminum and the balance being iron; heating the alloy to 800.degree. C. for between 175-250 hours prior to use in order to form a continuous silicon oxide film and another oxide film. The method provides a means of producing stainless steels with superior oxidation resistance at temperatures above 700.degree. C. at a low cost

  5. Antiviral Drug Resistance: Mechanisms and Clinical Implications

    PubMed Central

    Chou, Sunwen

    2010-01-01

    Summary Antiviral drug resistance is an increasing concern in immunocompromised patient populations, where ongoing viral replication and prolonged drug exposure lead to the selection of resistant strains. Rapid diagnosis of resistance can be made by associating characteristic viral mutations with resistance to various drugs as determined by phenotypic assays. Management of drug resistance includes optimization of host factors and drug delivery, selection of alternative therapies based on knowledge of mechanisms of resistance, and the development of new antivirals. This article discusses drug resistance in herpesviruses and hepatitis B. PMID:20466277

  6. Selective Insulin Resistance in Adipocytes*

    PubMed Central

    Tan, Shi-Xiong; Fisher-Wellman, Kelsey H.; Fazakerley, Daniel J.; Ng, Yvonne; Pant, Himani; Li, Jia; Meoli, Christopher C.; Coster, Adelle C. F.; Stöckli, Jacqueline; James, David E.

    2015-01-01

    Aside from glucose metabolism, insulin regulates a variety of pathways in peripheral tissues. Under insulin-resistant conditions, it is well known that insulin-stimulated glucose uptake is impaired, and many studies attribute this to a defect in Akt signaling. Here we make use of several insulin resistance models, including insulin-resistant 3T3-L1 adipocytes and fat explants prepared from high fat-fed C57BL/6J and ob/ob mice, to comprehensively distinguish defective from unaffected aspects of insulin signaling and its downstream consequences in adipocytes. Defective regulation of glucose uptake was observed in all models of insulin resistance, whereas other major actions of insulin such as protein synthesis and anti-lipolysis were normal. This defect corresponded to a reduction in the maximum response to insulin. The pattern of change observed for phosphorylation in the Akt pathway was inconsistent with a simple defect at the level of Akt. The only Akt substrate that showed consistently reduced phosphorylation was the RabGAP AS160 that regulates GLUT4 translocation. We conclude that insulin resistance in adipose tissue is highly selective for glucose metabolism and likely involves a defect in one of the components regulating GLUT4 translocation to the cell surface in response to insulin. PMID:25720492

  7. Adipocyte lipolysis and insulin resistance.

    PubMed

    Morigny, Pauline; Houssier, Marianne; Mouisel, Etienne; Langin, Dominique

    2016-06-01

    Obesity-induced insulin resistance is a major risk factor for the development of type 2 diabetes. Basal fat cell lipolysis (i.e., fat cell triacylglycerol breakdown into fatty acids and glycerol in the absence of stimulatory factors) is elevated during obesity and is closely associated with insulin resistance. Inhibition of adipocyte lipolysis may therefore be a promising therapeutic strategy for treating insulin resistance and preventing obesity-associated type 2 diabetes. In this review, we explore the relationship between adipose lipolysis and insulin sensitivity. After providing an overview of the components of fat cell lipolytic machinery, we describe the hypotheses that may support the causality between lipolysis and insulin resistance. Excessive circulating fatty acids may ectopically accumulate in insulin-sensitive tissues and impair insulin action. Increased basal lipolysis may also modify the secretory profile of adipose tissue, influencing whole body insulin sensitivity. Finally, excessive fatty acid release may also worsen adipose tissue inflammation, a well-known parameter contributing to insulin resistance. Partial genetic or pharmacologic inhibition of fat cell lipases in mice as well as short term clinical trials using antilipolytic drugs in humans support the benefit of fat cell lipolysis inhibition on systemic insulin sensitivity and glucose metabolism, which occurs without an increase of fat mass. Modulation of fatty acid fluxes and, putatively, of fat cell secretory pattern may explain the amelioration of insulin sensitivity whereas changes in adipose tissue immune response do not seem involved. PMID:26542285

  8. Resistivity monitoring at Cerro Prieto

    SciTech Connect

    Wilt, M.J.; Goldstein, N.E.

    1980-02-01

    In 1978 Lawrence Berkeley Laboratory, in cooperation with Comision Federal de Electricidad, began a program of dipole-dipole resistivity monitoring at the Cerro Prieto geothermal field. Dipole-dipole measurements were first made in 1978, then repeated in 1979: (a) to determine whether the field boundaries could be defined by surface resistivity measurements; and (b) to determine if changes in reservoir conditions due to production may be monitored by surface measurements. In 1979 data accuracy was improved to where estimated measurement errors were less than 3%. In addition, data coverage on a line over the field was expanded by 40% for greater depth of investigation and more information on the newer, eastern part of the field. Resistivity modeling of the expanded 1979 profile indicates that the resistive body associated with the zone of production (Wilt et al., 1978) dips steeply eastward, and may underlie the eastern part of the field. The model also shows a thin steeply dipping conductor adjacent to the resistive body that may be associated with faulting and fluid movement. Model perturbation studies have shown that small changes associated with cold-water influx, fault zone migrations, and formation of a steam zone would all be detectable with precision dipole-dipole measurements. Telluric profile measurements taken along line E-E' were found to yield a significant amount of reconnaissance information but are unsuitable for monitoring purposes.

  9. Orexin: Pathways to obesity resistance?

    PubMed Central

    Butterick, Tammy A.; Billington, Charles J.; Kotz, Catherine M.; Nixon, Joshua P.

    2016-01-01

    Obesity has increased in prevalence worldwide, attributed in part to the influences of an obesity-promoting environment and genetic factors. While obesity and overweight increasingly seem to be the norm, there remain individuals who resist obesity. We present here an overview of data supporting the idea that hypothalamic neuropeptide orexin A (OXA; hypocretin 1) may be a key component of brain mechanisms underlying obesity resistance. Prior work with models of obesity and obesity resistance in rodents has shown that increased orexin and/or orexin sensitivity is correlated with elevated spontaneous physical activity (SPA), and that orexin-induced SPA contributes to obesity resistance via increased non-exercise activity thermogenesis (NEAT). However, central hypothalamic orexin signaling mechanisms that regulate SPA remain undefined. Our ongoing studies and work of others support the hypothesis that one such mechanism may be upregulation of a hypoxia-inducible factor 1 alpha (HIF-1α)-dependent pathway, suggesting that orexin may promote obesity resistance both by increasing SPA and by influencing the metabolic state of orexin-responsive hypothalamic neurons. We discuss potential mechanisms based on both animal and in vitro pharmacological studies, in the context of elucidating potential molecular targets for obesity prevention and therapy. PMID:24005942

  10. Oxidative Stress and Insulin Resistance

    PubMed Central

    Park, Kyong; Gross, Myron; Lee, Duk-Hee; Holvoet, Paul; Himes, John H.; Shikany, James M.; Jacobs, David R.

    2009-01-01

    OBJECTIVE Although cumulative evidence suggests that increased oxidative stress may lead to insulin resistance in vivo or in vitro, community-based studies are scarce. This study examined the longitudinal relationships of oxidative stress biomarkers with the development of insulin resistance and whether these relationships were independent of obesity in nondiabetic young adults. RESEARCH DESIGN AND METHODS Biomarkers of oxidative stress (F2-isoprostanes [F2Isop] and oxidized LDL [oxLDL]), insulin resistance (the homeostasis model assessment of insulin resistance [HOMA-IR]), and various fatness measures (BMI, waist circumference, and estimated percent fat) were obtained in a population-based observational study (Coronary Artery Risk Development in Young Adults) and its ancillary study (Young Adult Longitudinal Trends in Antioxidants) during 2000–2006. RESULTS There were substantial increases in estimated mean HOMA-IR over time. OxLDL and F2Isop showed little association with each other. Mean evolving HOMA-IR increased with increasing levels of oxidative stress markers (P < 0.001 for oxLDL and P = 0.06 for F2Isop), measured in 2000–2001. After additional adjustment for adiposity, a positive association between oxLDL and HOMA-IR was strongly evident, whereas the association between F2Isop and HOMA-IR was not. CONCLUSIONS We observed positive associations between each of two oxidative stress markers and insulin resistance. The association with oxidized LDL was independent of obesity, but that with F2Isop was not. PMID:19389821

  11. Insulin Resistance in Alzheimer's Disease

    PubMed Central

    Dineley, Kelly T; Jahrling, Jordan B; Denner, Larry

    2014-01-01

    Insulin is a key hormone regulating metabolism. Insulin binding to cell surface insulin receptors engages many signaling intermediates operating in parallel and in series to control glucose, energy, and lipids while also regulating mitogenesis and development. Perturbations in the function of any of these intermediates, which occur in a variety of diseases, cause reduced sensitivity to insulin and insulin resistance with consequent metabolic dysfunction. Chronic inflammation ensues which exacerbates compromised metabolic homeostasis. Since insulin has a key role in learning and memory as well as directly regulating ERK, a kinase required for the type of learning and memory compromised in early Alzheimer's disease (AD), insulin resistance has been identified as a major risk factor for the onset of AD. Animal models of AD or insulin resistance or both demonstrate that AD pathology and impaired insulin signaling form a reciprocal relationship. Of note are human and animal model studies geared toward improving insulin resistance that have led to the identification of the nuclear receptor and transcription factor, peroxisome proliferator-activated receptor gamma (PPARγ) as an intervention tool for early AD. Strategic targeting of alternate nodes within the insulin signaling network has revealed disease-stage therapeutic windows in animal models that coalesce with previous and ongoing clinical trial approaches. Thus, exploiting the connection between insulin resistance and AD provides powerful opportunities to delineate therapeutic interventions that slow or block the pathogenesis of AD. PMID:25237037

  12. Tamoxifen Resistance: Emerging Molecular Targets

    PubMed Central

    Rondón-Lagos, Milena; Villegas, Victoria E.; Rangel, Nelson; Sánchez, Magda Carolina; Zaphiropoulos, Peter G.

    2016-01-01

    17β-Estradiol (E2) plays a pivotal role in the development and progression of breast cancer. As a result, blockade of the E2 signal through either tamoxifen (TAM) or aromatase inhibitors is an important therapeutic strategy to treat or prevent estrogen receptor (ER) positive breast cancer. However, resistance to TAM is the major obstacle in endocrine therapy. This resistance occurs either de novo or is acquired after an initial beneficial response. The underlying mechanisms for TAM resistance are probably multifactorial and remain largely unknown. Considering that breast cancer is a very heterogeneous disease and patients respond differently to treatment, the molecular analysis of TAM’s biological activity could provide the necessary framework to understand the complex effects of this drug in target cells. Moreover, this could explain, at least in part, the development of resistance and indicate an optimal therapeutic option. This review highlights the implications of TAM in breast cancer as well as the role of receptors/signal pathways recently suggested to be involved in the development of TAM resistance. G protein—coupled estrogen receptor, Androgen Receptor and Hedgehog signaling pathways are emerging as novel therapeutic targets and prognostic indicators for breast cancer, based on their ability to mediate estrogenic signaling in ERα-positive or -negative breast cancer. PMID:27548161

  13. Tamoxifen Resistance: Emerging Molecular Targets.

    PubMed

    Rondón-Lagos, Milena; Villegas, Victoria E; Rangel, Nelson; Sánchez, Magda Carolina; Zaphiropoulos, Peter G

    2016-01-01

    17β-Estradiol (E2) plays a pivotal role in the development and progression of breast cancer. As a result, blockade of the E2 signal through either tamoxifen (TAM) or aromatase inhibitors is an important therapeutic strategy to treat or prevent estrogen receptor (ER) positive breast cancer. However, resistance to TAM is the major obstacle in endocrine therapy. This resistance occurs either de novo or is acquired after an initial beneficial response. The underlying mechanisms for TAM resistance are probably multifactorial and remain largely unknown. Considering that breast cancer is a very heterogeneous disease and patients respond differently to treatment, the molecular analysis of TAM's biological activity could provide the necessary framework to understand the complex effects of this drug in target cells. Moreover, this could explain, at least in part, the development of resistance and indicate an optimal therapeutic option. This review highlights the implications of TAM in breast cancer as well as the role of receptors/signal pathways recently suggested to be involved in the development of TAM resistance. G protein-coupled estrogen receptor, Androgen Receptor and Hedgehog signaling pathways are emerging as novel therapeutic targets and prognostic indicators for breast cancer, based on their ability to mediate estrogenic signaling in ERα-positive or -negative breast cancer. PMID:27548161

  14. Intrinsic and acquired resistance mechanisms in enterococcus

    PubMed Central

    Hollenbeck, Brian L.; Rice, Louis B.

    2012-01-01

    Enterococci have the potential for resistance to virtually all clinically useful antibiotics. Their emergence as important nosocomial pathogens has coincided with increased expression of antimicrobial resistance by members of the genus. The mechanisms underlying antibiotic resistance in enterococci may be intrinsic to the species or acquired through mutation of intrinsic genes or horizontal exchange of genetic material encoding resistance determinants. This paper reviews the antibiotic resistance mechanisms in Enterococcus faecium and Enterococcus faecalis and discusses treatment options. PMID:23076243

  15. Head Resistance Due to Radiators

    NASA Technical Reports Server (NTRS)

    Kleinschmidt, R V; Parsons, S R

    1920-01-01

    Part 1 deals with the head resistance of a number of common types of radiator cores at different speeds in free air, as measured in the wind tunnel at the bureau of standards. This work was undertaken to determine the characteristics of various types of radiator cores, and in particular to develop the best type of radiator for airplanes. Some 25 specimens of core were tested, including practically all the general types now in use, except the flat plate type. Part 2 gives the results of wind tunnel tests of resistance on a model fuselage with a nose radiator. Part 3 presents the results of preliminary tests of head resistance of a radiator enclosed in a streamlined casing. Special attention is given to the value of wing radiator and of the radiator located in the open, especially when it is provided with a properly designed streamlined casing.

  16. Multiple Disease Resistance in Plants.

    PubMed

    Wiesner-Hanks, Tyr; Nelson, Rebecca

    2016-08-01

    Many plants, both in nature and in agriculture, are resistant to multiple diseases. Although much of the plant innate immunity system provides highly specific resistance, there is emerging evidence to support the hypothesis that some components of plant defense are relatively nonspecific, providing multiple disease resistance (MDR). Understanding MDR is of fundamental and practical interest to plant biologists, pathologists, and breeders. This review takes stock of the available evidence related to the MDR hypothesis. Questions about MDR are considered primarily through the lens of forward genetics, starting at the organismal level and proceeding to the locus level and, finally, to the gene level. At the organismal level, MDR may be controlled by clusters of R genes that evolve under diversifying selection, by dispersed, pathogen-specific genes, and/or by individual genes providing MDR. Based on the few MDR loci that are well-understood, MDR is conditioned by diverse mechanisms at the locus and gene levels. PMID:27296142

  17. Resistivity logging of fractured basalt

    SciTech Connect

    Stefansson, V.; Axelsson, G.; Sigurdsson, O.

    1982-01-01

    A lumped double porosity model was studied in order to estimate the effect of fractures on resistivity - porosity relations. It is found that the relationship between resistivity and porosity for fractured rock is in general not simple and depends both on the amounts of matrix porosity as well as the fracture orientation. However, when fractures dominate over matrix porosity the exponent is close to 1.0. Resistivity-porosity relations have been determined for large amounts of basaltic formations in Iceland. An exponent close to 1.0 is found in all cases investigated. This is interpreted as fractures constitute a considerable part of the porosity of the basalts. In the IRDP-hole in Eastern Iceland it is found that the ratio of fracture porosity to total porosity decreases with depth.

  18. Electrical resistivity of composite superconductors

    NASA Technical Reports Server (NTRS)

    Davis, J. H.; Lee, J. A.

    1983-01-01

    In addition to its superconducting properties, a superconductor is usually characterized by poor thermal conductivity and relatively high electrical resistivity in the normal state. To remedy this situation a study of superconducting properties of Cu-rich CU-Nb wires prepared by directionally solidified and cold-rolled technique was conducted. Some of the specimens were prepared by melting, directional solidification and diffusing in Tin. A total of 12 wire specimens was tested. Each specimen was analyzed by plotting experimental data into the following curves: the graph of the residual resistivity as a function of the specimen current at 4.3 K; and the graph of the electrical resistivity as a function of the temperature at a constant current.

  19. Quantum resistance metrology using graphene.

    PubMed

    Janssen, T J B M; Tzalenchuk, A; Lara-Avila, S; Kubatkin, S; Fal'ko, V I

    2013-10-01

    In this paper, we review the recent extraordinary progress in the development of a new quantum standard for resistance based on graphene. We discuss the unique properties of this material system relating to resistance metrology and discuss results of the recent highest-ever precision direct comparison of the Hall resistance between graphene and traditional GaAs. We mainly focus our review on graphene expitaxially grown on SiC, a system which so far resulted in the best results. We also briefly discuss progress in the two other graphene material systems, exfoliated graphene and chemical vapour deposition graphene, and make a critical comparison with SiC graphene. Finally, we discuss other possible applications of graphene in metrology. PMID:24088373

  20. Quantum resistance metrology using graphene

    NASA Astrophysics Data System (ADS)

    Janssen, T. J. B. M.; Tzalenchuk, A.; Lara-Avila, S.; Kubatkin, S.; Fal'ko, V. I.

    2013-10-01

    In this paper, we review the recent extraordinary progress in the development of a new quantum standard for resistance based on graphene. We discuss the unique properties of this material system relating to resistance metrology and discuss results of the recent highest-ever precision direct comparison of the Hall resistance between graphene and traditional GaAs. We mainly focus our review on graphene expitaxially grown on SiC, a system which so far resulted in the best results. We also briefly discuss progress in the two other graphene material systems, exfoliated graphene and chemical vapour deposition graphene, and make a critical comparison with SiC graphene. Finally, we discuss other possible applications of graphene in metrology.

  1. Static penetration resistance of soils

    NASA Technical Reports Server (NTRS)

    Durgunoglu, H. T.; Mitchell, J. K.

    1973-01-01

    Model test results were used to define the failure mechanism associated with the static penetration resistance of cohesionless and low-cohesion soils. Knowledge of this mechanism has permitted the development of a new analytical method for calculating the ultimate penetration resistance which explicitly accounts for penetrometer base apex angle and roughness, soil friction angle, and the ratio of penetration depth to base width. Curves relating the bearing capacity factors to the soil friction angle are presented for failure in general shear. Strength parameters and penetrometer interaction properties of a fine sand were determined and used as the basis for prediction of the penetration resistance encountered by wedge, cone, and flat-ended penetrometers of different surface roughness using the proposed analytical method. Because of the close agreement between predicted values and values measured in laboratory tests, it appears possible to deduce in-situ soil strength parameters and their variation with depth from the results of static penetration tests.

  2. Weed resistance challenges and management under herbicide resistant cropping systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Over the last six decades, herbicides have been the mainstay of weed management in cropping systems around the world, especially in the Western Hemisphere. A direct consequence of intensive use of herbicides is the development of resistance in weed populations. The extreme popularity of transgenic g...

  3. Dominant resistance against plant viruses

    PubMed Central

    de Ronde, Dryas; Butterbach, Patrick; Kormelink, Richard

    2014-01-01

    To establish a successful infection plant viruses have to overcome a defense system composed of several layers. This review will overview the various strategies plants employ to combat viral infections with main emphasis on the current status of single dominant resistance (R) genes identified against plant viruses and the corresponding avirulence (Avr) genes identified so far. The most common models to explain the mode of action of dominant R genes will be presented. Finally, in brief the hypersensitive response (HR) and extreme resistance (ER), and the functional and structural similarity of R genes to sensors of innate immunity in mammalian cell systems will be described. PMID:25018765

  4. Lipid signals and insulin resistance.

    PubMed

    Zhang, Chongben; Klett, Eric L; Coleman, Rosalind A

    2013-12-01

    The metabolic syndrome, a cluster of metabolic derangements that include obesity, glucose intolerance, dyslipidemia and hypertension, is a major risk factor for cardiovascular disease. Insulin resistance has been proposed to be the common feature that links obesity to the metabolic syndrome, but the mechanism remains obscure. Although the excess content of triacylglycerol in muscle and liver is highly associated with insulin resistance in these tissues, triacylglycerol itself is not causal but merely a marker. Thus, attention has turned to the accumulation of cellular lipids known to have signaling roles. This review will discuss recent progress in understanding how glycerolipids and related lipid intermediates may impair insulin signaling. PMID:24533033

  5. Computing motion using resistive networks

    NASA Technical Reports Server (NTRS)

    Koch, Christof; Luo, Jin; Mead, Carver; Hutchinson, James

    1988-01-01

    Recent developments in the theory of early vision are described which lead from the formulation of the motion problem as an ill-posed one to its solution by minimizing certain 'cost' functions. These cost or energy functions can be mapped onto simple analog and digital resistive networks. It is shown how the optical flow can be computed by injecting currents into resistive networks and recording the resulting stationary voltage distribution at each node. These networks can be implemented in cMOS VLSI circuits and represent plausible candidates for biological vision systems.

  6. Corrosion-resistant coating development

    SciTech Connect

    Stinton, D.P.; Kupp, D.M.; Martin, R.L.

    1997-12-01

    SiC-based heat exchangers have been identified as the prime candidate material for use as heat exchangers in advanced combined cycle power plants. Unfortunately, hot corrosion of the SiC-based materials created by alkali metal salts present in the combustion gases dictates the need for corrosion-resistant coatings. The well-documented corrosion resistance of CS-50 combined with its low (and tailorable) coefficient of thermal expansion and low modulus makes CS-50 an ideal candidate for this application. Coatings produced by gelcasting and traditional particulate processing have been evaluated.

  7. Antimicrobial Resistance in the Environment.

    PubMed

    Williams, Maggie R; Stedtfeld, Robert D; Guo, Xueping; Hashsham, Syed A

    2016-10-01

    This review summarizes important publications from 2015 pertaining to the occurrence of antimicrobial resistance (AMR) in the environment. Emphasis is placed on sources of antibiotic resistance in the aquatic environment including wastewater treatment plants, hospitals, and agriculture, treatment and mitigation techniques, and surveillance and analysis methodologies for characterizing abundance data. As such, this review is organized into the following sections: i) occurrence of AMR in the environment, including surface waters, aquaculture, and wastewater ii) treatment technologies, and iii) technologies for rapid surveillance of AMR, iv) transmission between matrices, v) databases and analysis methods, and vi) gaps in AMR understanding. PMID:27620115

  8. Fatigue-resistant photochromic plastics

    SciTech Connect

    Chu, Nori Y.C.

    1988-01-01

    The optical switching properties of a photochromic spirooxazine compound in retrofit polyester film and in poly(vinyl butyral) have been measured. The light fatigue resistance of these two optical switching elements were tested by an accelerated method. The length of photochromic activity of the optical switching elements can be improved by various organonickel and hindered amine light stabilizers. The effectiveness and optimal concentration for each light stabilizer in these host materials has been determined. These two types of light stabilizers act synergistically in improving the light fatigue resistance of the optical switching elements significantly. 14 refs., 2 figs., 3 tabs.

  9. Reflections on researching rape resistance.

    PubMed

    Ullman, Sarah E

    2014-03-01

    This article provides a retrospective account of my experience embarking on research about women's resistance to rape, including reflections on personal and professional experiences related to studying this topic. I discuss factors inspiring my interest, including pioneering feminist rape researchers, my experience as a woman living with the reality and fear of rape, and influential mentors who facilitated my career development as a scholar in graduate school and beyond. I weave this narrative together with my thoughts about how the study of resistance relates to other important issues in the field of sexual assault including alcohol, recovery, and prevention. PMID:24626768

  10. Mechanisms of resistance in castration-resistant prostate cancer (CRPC).

    PubMed

    Chandrasekar, Thenappan; Yang, Joy C; Gao, Allen C; Evans, Christopher P

    2015-06-01

    Despite advances in prostate cancer diagnosis and management, morbidity from prostate cancer remains high. Approximately 20% of men present with advanced or metastatic disease, while 29,000 men continue to die of prostate cancer each year. Androgen deprivation therapy (ADT) has been the standard of care for initial management of advanced or metastatic prostate cancer since Huggins and Hodges first introduced the concept of androgen-dependence in 1972, but progression to castration-resistant prostate cancer (CRPC) occurs within 2-3 years of initiation of ADT. CRPC, previously defined as hormone-refractory prostate cancer, is now understood to still be androgen dependent. Multiple mechanisms of resistance help contribute to the progression to castration resistant disease, and the androgen receptor (AR) remains an important driver in this progression. These mechanisms include AR amplification and hypersensitivity, AR mutations leading to promiscuity, mutations in coactivators/corepressors, androgen-independent AR activation, and intratumoral and alternative androgen production. More recently, identification of AR variants (ARVs) has been established as another mechanism of progression to CRPC. Docetaxel chemotherapy has historically been the first-line treatment for CRPC, but in recent years, newer agents have been introduced that target some of these mechanisms of resistance, thereby providing additional survival benefit. These include AR signaling inhibitors such as enzalutamide (Xtandi, ENZA, MDV-3100) and CYP17A1 inhibitors such as abiraterone acetate (Zytiga). Ultimately, these agents will also fail to suppress CRPC. While some of the mechanisms by which these agents fail are unique, many share similarities to the mechanisms contributing to CRPC progression. Understanding these mechanisms of resistance to ADT and currently approved CRPC treatments will help guide future research into targeted therapies. PMID:26814148

  11. Mechanisms of resistance in castration-resistant prostate cancer (CRPC)

    PubMed Central

    Chandrasekar, Thenappan; Yang, Joy C.; Gao, Allen C.

    2015-01-01

    Despite advances in prostate cancer diagnosis and management, morbidity from prostate cancer remains high. Approximately 20% of men present with advanced or metastatic disease, while 29,000 men continue to die of prostate cancer each year. Androgen deprivation therapy (ADT) has been the standard of care for initial management of advanced or metastatic prostate cancer since Huggins and Hodges first introduced the concept of androgen-dependence in 1972, but progression to castration-resistant prostate cancer (CRPC) occurs within 2-3 years of initiation of ADT. CRPC, previously defined as hormone-refractory prostate cancer, is now understood to still be androgen dependent. Multiple mechanisms of resistance help contribute to the progression to castration resistant disease, and the androgen receptor (AR) remains an important driver in this progression. These mechanisms include AR amplification and hypersensitivity, AR mutations leading to promiscuity, mutations in coactivators/corepressors, androgen-independent AR activation, and intratumoral and alternative androgen production. More recently, identification of AR variants (ARVs) has been established as another mechanism of progression to CRPC. Docetaxel chemotherapy has historically been the first-line treatment for CRPC, but in recent years, newer agents have been introduced that target some of these mechanisms of resistance, thereby providing additional survival benefit. These include AR signaling inhibitors such as enzalutamide (Xtandi, ENZA, MDV-3100) and CYP17A1 inhibitors such as abiraterone acetate (Zytiga). Ultimately, these agents will also fail to suppress CRPC. While some of the mechanisms by which these agents fail are unique, many share similarities to the mechanisms contributing to CRPC progression. Understanding these mechanisms of resistance to ADT and currently approved CRPC treatments will help guide future research into targeted therapies. PMID:26814148

  12. Potential of Tetracycline Resistance Proteins To Evolve Tigecycline Resistance

    PubMed Central

    Linkevicius, Marius; Sandegren, Linus

    2015-01-01

    Tigecycline is a glycylcycline antibiotic active against multidrug-resistant bacterial pathogens. The objectives of our study were to examine the potential of the Tet(A), Tet(K), Tet(M), and Tet(X) tetracycline resistance proteins to acquire mutations causing tigecycline resistance and to determine how this affects resistance to earlier classes of tetracyclines. Mutations in all four tet genes caused a significant increase in the tigecycline MIC in Escherichia coli, and strains expressing mutant Tet(A) and Tet(X) variants reached clinically relevant MICs (2 mg/liter and 3 mg/liter, respectively). Mutations predominantly accumulated in transmembrane domains of the efflux pumps, most likely increasing the accommodation of tigecycline as a substrate. All selected Tet(M) mutants contained at least one mutation in the functionally most important loop III of domain IV. Deletion of leucine 505 of this loop led to the highest increase of the tigecycline MIC (0.5 mg/liter) among Tet(M) mutants. It also caused collateral sensitivity to earlier classes of tetracyclines. A majority of the Tet(X) mutants showed increased activity against all three classes of tetracylines. All tested Tet proteins have the potential to acquire mutations leading to increased MICs of tigecycline. As tet genes are widely found in pathogenic bacteria and spread easily by horizontal gene transfer, resistance development by alteration of existing Tet proteins might compromise the future medical use of tigecycline. We predict that Tet(X) might become the most problematic future Tet determinant, since its weak intrinsic tigecycline activity can be mutationally improved to reach clinically relevant levels without collateral loss in activity to other tetracyclines. PMID:26596936

  13. Antibiotic and biocide resistance in methicillin-resistant Staphylococcus aureus and vancomycin-resistant enterococcus.

    PubMed

    Suller, M T; Russell, A D

    1999-12-01

    Concern has been growing regarding the potential of antibiotic and disinfectant co-resistance in clinically important bacteria. In this study, the susceptibilities of methicillin-resistant Staphylococcus aureus (MRSA) and methicillin-sensitive Staphylococcus aureus (MSSA) to chlorhexidine (CHX), the quaternary ammonium compounds cetylpyridinium chloride (CPC) and benzalkonium chloride (BC), triclosan, dibromopropamidine isethionate (DBPI) and triclocarban were compared. MRSA exhibited low-level resistance to CHX and the QACs, with MICs of 1.5 to 3-fold (CHX), and 2 to 4-fold (QACs) higher than MSSA. However, the MIC values for MRSA ranged between 0.025 (the MIC of MSSA) and 1 microg/mL with triclosan, and between <5 (the MIC of MSSA) and 75 microg/mL with DPBI. Nevertheless, these strains remain relatively sensitive to most of these antimicrobial agents. The bactericidal efficacy of CHX, CPC and DBPI (with the exception of one strain) correlated with their MIC value. This was not observed using triclosan; MRSA and MSSA strains were equally susceptible to its killing effect, regardless of MIC. The permeabilizing agent, ethylenediamine tetraacetic acid (EDTA) was unable to potentiate the antibacterial activities of the biocides against any of the strains tested. Attempts to select for staphylococcal strains with increased resistance to triclosan, CPC or CHX, using disc diffusion, step-wise broth, or repeated exposure/recovery technique, were only partially successful, and resistance was found to be unstable. The susceptibilities of vancomycin-resistant enterococcus (VRE) and vancomycin-sensitive enterococcus (VSE) to the biocides were also compared and found to be similar both in terms of MIC testing and time-kill studies. PMID:10658804

  14. Extensively drug-resistant tuberculosis.

    PubMed

    Jassal, Mandeep; Bishai, William R

    2009-01-01

    Extensively drug-resistant (XDR) tuberculosis is defined as disease caused by Mycobacterium tuberculosis with resistance to at least isoniazid and rifampicin, any fluoroquinolone, and at least one of three injectable second-line drugs (amikacin, capreomycin, or kanamycin). The definition has applicable clinical value and has allowed for more uniform surveillance in varied international settings. Recent surveillance data have indicated that the prevalence of tuberculosis drug resistance has risen to the highest rate ever recorded. The gold standard for drug-susceptibility testing has been the agar proportion method; however, this technique requires several weeks for results to be determined. More sensitive and specific diagnostic tests are still unavailable in resource-limited settings. Clinical manifestations, although variable in different settings and among different strains, have in general shown that XDR tuberculosis is associated with greater morbidity and mortality than non-XDR tuberculosis. The treatment of XDR tuberculosis should include agents to which the organism is susceptible, and should continue for a minimum of 18-24 months. However, treatment continues to be limited in tuberculosis-endemic countries largely because of weaknesses in national tuberculosis health-care models. The ultimate strategy to control drug-resistant tuberculosis is one that implements a comprehensive approach incorporating innovation from the political, social, economic, and scientific realms. PMID:18990610

  15. Spatial mapping of antibiotic resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A serious concern for modern animal production is the fear that feed antimicrobials, such as monensin, increase the potential for high levels of antibiotic resistant (AR) gene prevalence in the manure, which may subsequently be shared with soil communities and eventually be taken up by human pathoge...

  16. Compact, Controlled Resistance Exercise Device

    NASA Technical Reports Server (NTRS)

    Paulus, David C.; DeWitt, John K.; Reich, Alton J.; Shaw, James E.; Deaconu, Stelu S.

    2011-01-01

    Spaceflight leads to muscle and bone atrophy. Isoinertial (free-weight) exercises provide a sufficient stimulus to elicit increases in both muscle strength and bone mineral density in Earth-based studies. While exercise equipment is in use on the International Space Station for crewmember health maintenance, current devices are too large to place in a transport vehicle or small spacecraft. Therefore, a portable computer controlled resistance exercise device is being developed that is able to simulate the inertial loading experienced when lifting a mass on Earth. This portable device weighs less than 50 lb and can simulate the resistance of lifting and lowering up to 600 lb of free-weights. The objective is to allow crewmembers to perform resistance exercise with loads capable of maintaining muscle and bone health. The device is reconfigurable and allows for the performance of typical Earth-based free-weight exercises. Forces exerted, volume of work, range of motion, time-under-tension, and speed/ acceleration of movement are recorded and can be remotely monitored to track progress and modify individual protocols based on exercise session data. A performance evaluation will be completed and data will be presented that include ground-reaction force comparisons between the device and free-weight dead-lifts over a spectrum of resistance levels. Movement biomechanics will also be presented.

  17. Macrophages in resistance to candidiasis.

    PubMed Central

    Vázquez-Torres, A; Balish, E

    1997-01-01

    Candida albicans, an increasingly common opportunistic pathogenic fungus, frequently causes disease in immunodeficient but not immunocompetent hosts. Clarifying the role of the phagocytic cells that participate in resistance to candidiasis not only is basic to understanding how the host copes with this dimorphic pathogen but also will expedite the development of innovative prophylactic and therapeutic approaches for treating the multiple clinical presentations that candidiasis encompasses. In this review, we present evidence that a diverse population of mononuclear phagocytes, in different states of activation and differentiation and from a variety of host species, can phagocytize C. albicans blastoconidia via an array of opsonic and nonopsonic mechanisms and can kill C. albicans blastoconidia and hyphae by means of oxygen-dependent and -independent mechanisms. Reactive nitrogen intermediates should now be added to the well-established candidacidal reactive oxygen intermediates of macrophages. Furthermore, what were thought to be two independent pathways, i.e., nitric oxide and superoxide anion, have now been shown to combine to form a potent macrophage candidacidal molecule, peroxynitrite. In contrast to monocytes and neutrophils, which are important in resistance to early stages of C. albicans infections, more differentiated macrophages activated by cytokines such as gamma interferon participate in the acquired resistance of hosts with C. albicans-specific, cell-mediated immunity. Evidence presented in this review demonstrates that mononuclear phagocytes, in some instances in the absence of other professional phagocytes such as neutrophils, play an import role in resistance to systemic and mucosal candidiasis. PMID:9184009

  18. Germplasm enhancement for RWA resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our contribution to this annual report is a summary of research accomplishments for 2008 in germplasm enhancement for RWA resistance in barley at the USDA-ARS Wheat, Peanuts and other Field Crops Research Unit, Stillwater, OK. RWA is a serious pest of barley in the intermountain regions of the west...

  19. Popular Media, Education, and Resistance

    ERIC Educational Resources Information Center

    Stack, Michelle; Kelly, Deirdre M.

    2006-01-01

    Although the mainstream media and education systems are key institutions that perpetuate various social inequalities, spaces exist--both within and beyond these institutions--where adults and youth resist dominant, damaging representations and improvise new images. In this article, we address why educational researchers and educators should attend…

  20. Fire resistant nuclear fuel cask

    DOEpatents

    Heckman, Richard C.; Moss, Marvin

    1979-01-01

    The disclosure is directed to a fire resistant nuclear fuel cask employing reversibly thermally expansible bands between adjacent cooling fins such that normal outward flow of heat is not interfered with, but abnormal inward flow of heat is impeded or blocked.

  1. GERMPLASM ENHANCEMENT FOR RWA RESISTANCE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our contribution to this annual newsletter is a summary of research accomplishments in the past year in germplasm enhancement for RWA resistance in barley at the USDA-ARS Plant Science and Water Conservation Research Laboratory, Stillwater, OK. RWA is a serious pest of barley in the intermountain r...

  2. Insecticide resistance and dominance levels.

    PubMed

    Bourguet, D; Genissel, A; Raymond, M

    2000-12-01

    Dominance has been assessed in different ways in insecticide resistance studies, based on three phenotypic traits: the insecticide concentration required to give a particular mortality (DLC), mortality at a particular insecticide dose (DML), and fitness in treated areas (DWT). We propose a general formula for estimating dominance on a scale of 0 to 1 (0 = complete recessivity and 1 = complete dominance). DLC, DML, and DWT are not directly related and their values depend on genetic background and environmental conditions. We also show that pest management strategies can have the consequence to increase DWT via the selection of dominance modifiers. Studies on resistance to Bacillus thuringiensis toxins provide the ultimate example of the complexity of the definition of the concept of dominance. Almost all studies have focused on calculation of DLC, which provides little information about the efficiency of pest management programs. For instance, one assumption of the high dose/refuge strategy is that Bacillus thuringiensis resistance must be effectively recessive (i.e., DML must be close to zero). However, DWT, rather than DML, is relevant to the resistance management strategy. Therefore, we strongly suggest that the time has come to focus on fitness dominance levels in the presence and absence of insecticide. PMID:11142285

  3. Resistive flex sensors: a survey

    NASA Astrophysics Data System (ADS)

    Saggio, Giovanni; Riillo, Francesco; Sbernini, Laura; Quitadamo, Lucia Rita

    2016-01-01

    Resistive flex sensors can be used to measure bending or flexing with relatively little effort and a relatively low budget. Their lightness, compactness, robustness, measurement effectiveness and low power consumption make these sensors useful for manifold applications in diverse fields. Here, we provide a comprehensive survey of resistive flex sensors, taking into account their working principles, manufacturing aspects, electrical characteristics and equivalent models, useful front-end conditioning circuitry, and physic-bio-chemical aspects. Particular effort is devoted to reporting on and analyzing several applications of resistive flex sensors, related to the measurement of body position and motion, and to the implementation of artificial devices. In relation to the human body, we consider the utilization of resistive flex sensors for the measurement of physical activity and for the development of interaction/interface devices driven by human gestures. Concerning artificial devices, we deal with applications related to the automotive field, robots, orthosis and prosthesis, musical instruments and measuring tools. The presented literature is collected from different sources, including bibliographic databases, company press releases, patents, master’s theses and PhD theses.

  4. Resistive band for turbomachine blade

    SciTech Connect

    Roberts, Herbert Chidsey; Taxacher, Glenn Curtis

    2015-08-25

    A turbomachine system includes a rotor that defines a longitudinal axis of the turbomachine system. A first blade is coupled to the rotor, and the first blade has first and second laminated plies. A first band is coupled to the first blade and is configured to resist separation of the first and second laminated plies.

  5. Treating Diuretic Resistance: An Overview.

    PubMed

    Bowman, Brandi N; Nawarskas, James J; Anderson, Joe R

    2016-01-01

    Loop diuretics are central to the management of fluid overload in acute decompensated heart failure. However, a variance in the response to loop diuretics can alter a patient's clinical course and has an adverse effect on clinical outcomes. Thus, a diminished response to loop diuretics is an important clinical issue. Factors thought to contribute to diuretic resistance include erratic oral absorption in congested states and postdiuretic sodium retention. Further contributing to diuretic resistance in patients with advanced heart failure are decreases in renal perfusion and alterations in sodium handling that occur in an attempt to maintain circulatory homeostasis. Several pharmacologic interventions have been used to improve diuretic response. Intravenous diuretic administration, increasing diuretic doses, or changing diuretic agents can potentially overcome pharmacokinetic obstacles which contribute to drug resistance. Combination diuretic therapy may be useful to overcome increased sodium retention, dopamine may improve renal perfusion, and hypertonic saline may transiently increase intravascular volume and improve sodium delivery to the tubules of the nephron. Despite the prevalence of diuretic resistance, there remains a paucity of clinical trial evidence to help guide therapy in these patients. PMID:27465540

  6. Germplasm enhancement for RWA resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our contribution to this annual report is a summary of research accomplishments for 2010 in germplasm enhancement for RWA resistance in barley at the USDA-ARS, Wheat, Peanuts and other Field Crops Research Unit, Stillwater, OK. RWA is a serious pest of barley in the intermountain regions of the wes...

  7. Germplasm enhancement for RWA resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our contribution to this annual newsletter is a summary of research accomplishments in the past year in germplasm enhancement for RWA resistance in barley at the USDA-ARS Wheat, Peanut and Other Field Crops Research Unit, Stillwater, OK. RWA is a serious pest of barley in the intermountain regions ...

  8. Bioassays for Monitoring Insecticide Resistance

    PubMed Central

    Miller, Audra L.E.; Tindall, Kelly; Leonard, B. Rogers

    2010-01-01

    Pest resistance to pesticides is an increasing problem because pesticides are an integral part of high-yielding production agriculture. When few products are labeled for an individual pest within a particular crop system, chemical control options are limited. Therefore, the same product(s) are used repeatedly and continual selection pressure is placed on the target pest. There are both financial and environmental costs associated with the development of resistant populations. The cost of pesticide resistance has been estimated at approximately $ 1.5 billion annually in the United States. This paper will describe protocols, currently used to monitor arthropod (specifically insects) populations for the development of resistance. The adult vial test is used to measure the toxicity to contact insecticides and a modification of this test is used for plant-systemic insecticides. In these bioassays, insects are exposed to technical grade insecticide and responses (mortality) recorded at a specific post-exposure interval. The mortality data are subjected to Log Dose probit analysis to generate estimates of a lethal concentration that provides mortality to 50% (LC50) of the target populations and a series of confidence limits (CL's) as estimates of data variability. When these data are collected for a range of insecticide-susceptible populations, the LC50 can be used as baseline data for future monitoring purposes. After populations have been exposed to products, the results can be compared to a previously determined LC50 using the same methodology. PMID:21248689

  9. CORROSION RESISTANT JACKETED METAL BODY

    DOEpatents

    Brugmann, E.W.

    1958-08-26

    Reactor faul elements of the elongated cylindrical type which are jacketed in a corrosion resistant material are described. Each feel element is comprised of a plurality of jacketed cylinders of fissionable material in end to end abutting relationship, the jackets being welded together at their adjoining ends to retain the individual segments together and seat the interior of the jackets.

  10. Developing disease resistant stone fruits

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Stone fruit (Prunus spp.) (peach, nectarine, plum, apricot, cherry) and almonds are susceptible to a number of pathogens. These pathogens can cause extensive losses in the field, during transport and storage, and in the market. Breeding for disease resistance requires an extensive knowledge of the...

  11. Nutritional Modulation of Insulin Resistance

    PubMed Central

    Weickert, Martin O.

    2012-01-01

    Insulin resistance has been proposed as the strongest single predictor for the development of Type 2 Diabetes (T2DM). Chronic oversupply of energy from food, together with inadequate physical activity, have been recognized as the most relevant factors leading to overweight, abdominal adiposity, insulin resistance, and finally T2DM. Conversely, energy reduced diets almost invariably to facilitate weight loss and reduce abdominal fat mass and insulin resistance. However, sustained weight loss is generally difficult to achieve, and distinct metabolic characteristics in patients with T2DM further compromise success. Therefore, investigating the effects of modulating the macronutrient composition of isoenergetic diets is an interesting concept that may lead to additional important insights. Metabolic effects of various different dietary concepts and strategies have been claimed, but results from randomized controlled studies and particularly from longer-term-controlled interventions in humans are often lacking. However, some of these concepts are supported by recent research, at least in animal models and short-term studies in humans. This paper provides an update of the current literature regarding the role of nutrition in the modulation of insulin resistance, which includes the discussion of weight-loss-independent metabolic effects of commonly used dietary concepts. PMID:24278690

  12. Transgenic Crops for Herbicide Resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since their introduction in 1995, crops made resistant to the broad-spectrum herbicides glyphosate and glufosinate with transgenes are widely available and used in much of the world. As of 2008, over 80% of the transgenic crops grown world-wide have this transgenic trait. This technology has had m...

  13. Resists for next generation lithography

    SciTech Connect

    Brainard, Robert L.; Barclay, George G.; Anderson, Erik H.; Ocola, Leonidas E.

    2001-10-03

    Four Next Generation Lithographic options (EUV, x-ray, EPL, IPL) are compared against four current optical technologies (i-line, DUV, 193 nm, 157 nm) for resolution capabilities based on wavelength. As the wavelength of the incident radiation decreases, the nature of the interaction with the resist changes. At high energies, optical density is less sensitive to molecular structure then at 157 nm.

  14. Corrosion resistant metallic bipolar plate

    DOEpatents

    Brady, Michael P.; Schneibel, Joachim H.; Pint, Bruce A.; Maziasz, Philip J.

    2007-05-01

    A corrosion resistant, electrically conductive component such as a bipolar plate for a PEM fuel cell includes 20 55% Cr, balance base metal such as Ni, Fe, or Co, the component having thereon a substantially external, continuous layer of chromium nitride.

  15. Drug targeting of leptin resistance.

    PubMed

    Santoro, Anna; Mattace Raso, Giuseppina; Meli, Rosaria

    2015-11-01

    Leptin regulates glucose, lipid and energy homeostasis as well as feeding behavior, serving as a bridge between peripheral metabolically active tissues and the central nervous system (CNS). Indeed, this adipocyte-derived hormone, whose circulating levels mirror fat mass, not only exerts its anti-obesity effects mainly modulating the activity of specific hypothalamic neurons expressing the long form of the leptin receptor (Ob-Rb), but it also shows pleiotropic functions due to the activation of Ob-Rb in peripheral tissues. Nevertheless, several mechanisms have been suggested to mediate leptin resistance, including obesity-associated hyperleptinemia, impairment of leptin access to CNS and the reduction in Ob-Rb signal transduction effectiveness, among others. During the onset and progression of obesity, the dampening of leptin sensitivity often occurs, preventing the efficacy of leptin replacement therapy from overcoming obesity and/or its comorbidities. This review focuses on obesity-associated leptin resistance and the mechanisms underpinning this condition, to highlight the relevance of leptin sensitivity restoration as a useful therapeutic strategy to treat common obesity and its complications. Interestingly, although promising strategies to counteract leptin resistance have been proposed, these pharmacological approaches have shown limited efficacy or even relevant adverse effects in preclinical and clinical studies. Therefore, the numerous findings from this review clearly indicate a lack of a single and efficacious treatment for leptin resistance, highlighting the necessity to find new therapeutic tools to improve leptin sensitivity, especially in patients with most severe disease profiles. PMID:26071010

  16. Germplasm enhancement for RWA resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our contribution to this annual newsletter is a summary of research accomplishments in the past year in germplasm enhancement for RWA resistance in barley at the USDA-ARS, Wheat, Peanut and Other Field Crops Research Unit, Stillwater, OK. RWA is a serious pest of barley in the intermountain regions...

  17. Germplasm enhancement for RWA resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our contribution to this annual newsletter is a summary of research accomplishments in the past year in germplasm enhancement for RWA resistance in barley at the USDA-ARS Wheat, Peanut and Other Field Crops Research Unit, Stillwater, OK. Russian wheat aphid (RWA) is a serious pest of barley in the ...

  18. [PREDICTORS OF RESISTANT ARTERIAL HYPERTENSION].

    PubMed

    Lazutkina, A Y; Gorbunov, V V

    2016-01-01

    The paper reports results of 6 year prospective observation of 7959 members of locomotive crews engaged at the Transbaikal Railways. The study aimed to estimate the probability and time of development of resistant arterial hypertension under effect of predictors of this disease. The data obtained are of value for diagnostic, prophylactic, and therapeutic practice. PMID:27522725

  19. Oxidation resistance of silicon ceramics

    NASA Technical Reports Server (NTRS)

    Yasutoshi, H.; Hirota, K.

    1984-01-01

    Oxidation resistance, and examples of oxidation of SiC, Si3N4 and sialon are reviewed. A description is given of the oxidation mechanism, including the oxidation product, oxidation reaction and the bubble size. The oxidation reactions are represented graphically. An assessment is made of the oxidation process, and an oxidation example of silicon ceramics is given.

  20. PROGRAMS FOR MONITORING ANTIMICROBIAL RESISTANCE

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Use of antimicrobials has increased in both human and veterinary medicine and the emergence of resistance to antimicrobials has become a global problem. This is due, in part, to the widespread availability of antimicrobials and the efficacy they impart in control of certain infectious diseases. An...

  1. The Internal Resistance of Supercapacitors

    ERIC Educational Resources Information Center

    Costa, G. G. G.; Pietronero, R. C.; Catunda, T.

    2012-01-01

    In this paper we study the transient behaviour of RC circuits with supercapacitors, varying R between 1 and 100 [omega]. We demonstrate that supercapacitors behave as ideal capacitors in series with an internal resistance (r [similar to] 8 [omega] for C = 0.2 F, 5.5 V). This result is important to optimize the demonstration of RC circuits using a…

  2. Engineering Antimicrobials Refractory to Resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Multi-drug resistant superbugs are a persistent problem in modern health care, demonstrating the need for a new class of antimicrobials that can address this concern. Triple-acting peptidoglycan hydrolase fusions are a novel class of antimicrobials which have qualities well suited to avoiding resis...

  3. Resistivity Problems in Electrostatic Precipitation

    ERIC Educational Resources Information Center

    White, Harry J.

    1974-01-01

    The process of electrostatic precipitation has ever-increasing application in more efficient collection of fine particles from industrial air emissions. This article details a large number of new developments in the field. The emphasis is on high resistivity particles which are a common cause of poor precipitator performance. (LS)

  4. Germplasm enhancement for RWA resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Our contribution to this annual report is a summary of research accomplishments for 2007 in germplasm enhancement for RWA resistance in barley at the USDA-ARS Wheat, Peanuts and other Field Crops Research Unit, Stillwater, OK. RWA is a serious pest of barley in the intermountain regions of the west...

  5. Scrapie resistance in ARQ sheep

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Susceptibility of sheep to classical scrapie is strongly influenced by genetic variation in the ovine prion gene (PRNP), especially at amino acid residues 136, 154 and 171. Sheep with the A136R154R171 haplotype are considered resistant, while those homozygous for A136R154Q171 are susceptible. How...

  6. Automation of Resistance Bridge Calibrator

    NASA Astrophysics Data System (ADS)

    Podgornik, Tadej; Bojkovski, Jovan; Batagelj, Valentin; Drnovšek, Janko

    2008-02-01

    The article addresses the automation of the resistance bridge calibrator (RBC). The automation of the RBC is performed in order to facilitate the operation of the RBC, improve the reliability, and enable several additional possibilities compared to the tedious manual operation, thereby making the RBC a more practical device for routine use. The RBC is used to calibrate AC and DC resistance bridges, which are mainly used in a primary thermometry laboratory. It consists of a resistor network made up from four main resistors from which 35 different resistance values can be realized using toggle switches. Literature shows that the resistors’ non-zero temperature coefficient can influence the measurements, causing difficulties when calibrating resistance bridges with low uncertainty. Placing the RBC in a thermally stable environment can reduce this, but it does not solve the problem of the time-consuming manual selection of the resistance values. To solve this, an automated means to manipulate the switches, while the device is placed within a thermally stable environment, was created. Computer operation completely substitutes for any manual operation during which an operator would normally have to be present. The computer also acquires measurements from the bridge. In this way, repeated and reproducible calibration measurements inside a temperature-stable environment can be carried out with no active involvement of personnel. The automation process itself was divided into several stages. They included the construction of a servo-manipulator to move the switches, the design of a dedicated electronic controller that also provides a serial interface (RS-232) to the computer, and the development of custom computer software to configure the servo-manipulator and control the calibration process. Measurements show that automation does not affect the long-term stability and mechanical repeatability of the RBC. The repeatability and reproducibility of bridge calibration ratios

  7. Anthelmintic resistance in equine nematodes

    PubMed Central

    Matthews, Jacqueline B.

    2014-01-01

    Anthelmintics have been applied indiscriminately to control horse nematodes for over 40 years. Three broad-spectrum anthelmintic classes are currently registered for nematode control in horses: benzimidazoles (fenbendazole, oxibendazole), tetrahydropyrimidines (pyrantel) and macrocyclic lactones (ivermectin, moxidectin). Generally, control strategies have focused on nematode egg suppression regimens that involve the frequent application of anthelmintics to all horses at intervals based on strongyle egg reappearance periods after treatment. The widespread use of such programmes has substantially reduced clinical disease, especially that associated with large strongyle species; however, high treatment frequency has led to considerable selection pressure for anthelmintic resistance, particularly in cyathostomin species. Field studies published over the last decade indicate that benzimidazole resistance is widespread globally in cyathostomins and there are also many reports of resistance to pyrantel in these worms. Cyathostomin resistance to macrocyclic lactone compounds is emerging, principally measured as a reduction in strongyle egg reappearance time observed after treatment. Ivermectin resistance is a further concern in the small intestinal nematode, Parascaris equorum, an important pathogen of foals. These issues indicate that horse nematodes must now be controlled using methods less dependent on anthelmintic use and more reliant on management practices designed to reduce the force of infection in the environment. Such strategies include improved grazing management integrated with targeted anthelmintic administration involving faecal egg count (FEC)-directed treatments. The latter require that the supporting diagnostic tests available are robust and practically applicable. Recent research has focused on maximising the value of FEC analysis in horses and on optimizing protocols for anthelmintic efficacy testing. Other studies have sought to develop diagnostics

  8. Anthelmintic resistance in equine nematodes.

    PubMed

    Matthews, Jacqueline B

    2014-12-01

    Anthelmintics have been applied indiscriminately to control horse nematodes for over 40 years. Three broad-spectrum anthelmintic classes are currently registered for nematode control in horses: benzimidazoles (fenbendazole, oxibendazole), tetrahydropyrimidines (pyrantel) and macrocyclic lactones (ivermectin, moxidectin). Generally, control strategies have focused on nematode egg suppression regimens that involve the frequent application of anthelmintics to all horses at intervals based on strongyle egg reappearance periods after treatment. The widespread use of such programmes has substantially reduced clinical disease, especially that associated with large strongyle species; however, high treatment frequency has led to considerable selection pressure for anthelmintic resistance, particularly in cyathostomin species. Field studies published over the last decade indicate that benzimidazole resistance is widespread globally in cyathostomins and there are also many reports of resistance to pyrantel in these worms. Cyathostomin resistance to macrocyclic lactone compounds is emerging, principally measured as a reduction in strongyle egg reappearance time observed after treatment. Ivermectin resistance is a further concern in the small intestinal nematode, Parascaris equorum, an important pathogen of foals. These issues indicate that horse nematodes must now be controlled using methods less dependent on anthelmintic use and more reliant on management practices designed to reduce the force of infection in the environment. Such strategies include improved grazing management integrated with targeted anthelmintic administration involving faecal egg count (FEC)-directed treatments. The latter require that the supporting diagnostic tests available are robust and practically applicable. Recent research has focused on maximising the value of FEC analysis in horses and on optimizing protocols for anthelmintic efficacy testing. Other studies have sought to develop diagnostics

  9. Multiple antibiotic resistance in Rhizobium japonicum.

    PubMed

    Cole, M A; Elkan, G H

    1979-05-01

    A total of 48 strains of the soil bacterium Rhizobium japonicum were screened for their response to several widely used antibiotics. Over 60% of the strains were resistant to chloramphenicol, polymyxin B, and erythromycin, and 47% or more of the strains were resistant to neomycin and penicillin G, when tested by disk assay procedures. The most common grouping of resistances in strains was simultaneous resistance to tetracycline, penicillin G, neomycin, chloramphenicol, and streptomycin (25% of all strains tested). The occurrence of multiple drug resistance in a soil bacterium that is not a vertebrate pathogen suggests that chemotherapeutic use of antibiotics is not required for the development of multiple drug resistance. PMID:485137

  10. Improvement of Dry Etching Resistance of Cyclized Polybutadiene Negative Resist by Vacuum Baking

    NASA Astrophysics Data System (ADS)

    Shimizu, Toshio; Cornu, Vanessa

    1992-12-01

    The dry etching resistance of cyclized polybutadiene negative resist, baked both in air and in vacuum, was investigated. After postbaking in air at above 160°C, the resist etching rate sharply rises. It was clarified by differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FT-IR, RAS method) and X-ray photoelectron spectroscopy (XPS) that the resist oxidation decreases dry etching resistance. On the other hand, the highest resistance was obtained by baking the resist in vacuum at 200°C. The postbaking technique was confirmed as a method for increasing-dry etching resistance.

  11. Acetolactate Synthase-Inhibiting Herbicide-Resistant Rice Flatsedge (Cyperus iria): Cross Resistance and Molecular Mechanism of Resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Overuse of acetolactate synthase (ALS) –inhibiting herbicides in rice has led to evolution of halosulfuron-resistant rice flatsedge (Cyperus iria L.) in Arkansas (AR) and Mississippi (MS), USA. Resistant accessions were cross-resistant to labeled field rates of ALS-inhibiting herbicides from four d...

  12. Insecticide resistance in house flies from the United States: Resistance levels and frequency of pyrethroid resistance alleles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although insecticide resistance is a widespread problem for most insect pests, frequently the assessment of resistance occurs over a limited geographic range. Herein we report the first widespread survey of insecticide resistance ever undertaken for the house fly, Musca domestica, a major pest of a...

  13. TWO MAJOR RESISTANCE GENES CONFER RESISTANCE TO RACE SHIFT ISOLATES OVERCOMING BLAST RESISTANCE GENC PI-TA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    One of the major challenges for blast disease management is that major resistance genes are often defeated by new virulent isolates. The goal of this project is to identify and characterize blast resistance genes to facilitate the development of blast resistant US cultivars by marker-assisted selec...

  14. YAP and the drug resistance highway

    PubMed Central

    Keren-Paz, Alona; Emmanuel, Rafi

    2016-01-01

    Deciphering mechanisms of drug resistance is crucial to winning the battle against cancer. A new study points to an unexpected function of YAP in drug resistance and illuminates its potential role as a therapeutic target. PMID:25711863

  15. YAP and the drug resistance highway.

    PubMed

    Keren-Paz, Alona; Emmanuel, Rafi; Samuels, Yardena

    2015-03-01

    Deciphering mechanisms of drug resistance is crucial to winning the battle against cancer. A new study points to an unexpected function of YAP in drug resistance and illuminates its potential role as a therapeutic target. PMID:25711863

  16. RESIDENTIAL RADON RESISTANT CONSTRUCTION FEATURE SELECTION SYSTEM

    EPA Science Inventory

    The report describes a proposed residential radon resistant construction feature selection system. The features consist of engineered barriers to reduce radon entry and accumulation indoors. The proposed Florida standards require radon resistant features in proportion to regional...

  17. Arc track resistant polymers for space applications

    NASA Technical Reports Server (NTRS)

    Haghighat, Ross

    1995-01-01

    The properties and test methods of aorimide polymers, kapton, and fep teflon are given in table format. Graphic depiction of an atomic oxygen resistance comparison, arc track resistance set-up and arc incident vs. propagation are given.

  18. Reaction Mechanism of Extreme Ultraviolet Resists

    NASA Astrophysics Data System (ADS)

    Toriumi, Minoru; Kaneyama, Koji; Itani, Toshiro

    2008-06-01

    Molecular resist of polyphenol was evaluated as an extreme-ultraviolet resist compared with a polymer resist of poly(tert-butoxycarbonylhydroxystyrene). X-ray reflectometry was used to determine the resist-film density and measurement accuracy was improved. The molecular resist shows higher sensitivity of 3 mJ/cm2 than the polymer resist of 4 mJ/cm2. The deprotection mechanism was approximated by simple reaction equations and Fourier-transform infrared spectra was interpreted to give the products of a quantum yield and a deprotection rate constant as 9.7×10-8 and 8.1×10-8 cm3 molecule-1 s-1 for molecular and polymer resists. The higher sensitivity of the molecular resist is due to the larger efficiency of the reaction mechanism.

  19. Methods for resistive switching of memristors

    DOEpatents

    Mickel, Patrick R.; James, Conrad D.; Lohn, Andrew; Marinella, Matthew; Hsia, Alexander H.

    2016-05-10

    The present invention is directed generally to resistive random-access memory (RRAM or ReRAM) devices and systems, as well as methods of employing a thermal resistive model to understand and determine switching of such devices. In particular example, the method includes generating a power-resistance measurement for the memristor device and applying an isothermal model to the power-resistance measurement in order to determine one or more parameters of the device (e.g., filament state).

  20. Agents of Last Resort: Polymyxin Resistance.

    PubMed

    Kaye, Keith S; Pogue, Jason M; Tran, Thien B; Nation, Roger L; Li, Jian

    2016-06-01

    Polymyxin resistance is a major public health threat, as the polymyxins represent "last-line" therapeutics for Gram-negative pathogens resistant to essentially all other antibiotics. Improved understanding of mechanisms of, and risk factors for, polymyxin resistance, as well as infection prevention and stewardship strategies, together with optimization of dosing of polymyxins including in combination regimens, can help to limit the emergence and dissemination of polymyxin resistance. PMID:27208765

  1. Residual Resistivity of Dilute Alloys

    NASA Astrophysics Data System (ADS)

    Vora, Aditya M.

    The residual resistivity for 156 dilute alloys of 19 hosts of different groups of the periodic table has been studied on the basis of the single parametric model potential formalism. Ashcroft's empty core model (EMC) potential is explored for the first time with five different local field correction functions, viz, Hartree (H), Taylor (T), Ichimaru-Utsumi (IU), Farid et al. (F), and Sarkar et al. (S) to investigate the effect of the exchange and correlation on the aforesaid properties. The comparison of the presently computed outcomes with the available theoretical and experimental data is highly encouraging. The investigation of residual resistivity is found to be quite sensitive to the selection of local field correction function, showing a significant variation with the change in the function.

  2. Transient scattering by resistive cylinders

    NASA Astrophysics Data System (ADS)

    Damaskos, N. J.; Brown, R. T.; Jameson, J. R.; Uslenghi, P. L. E.

    1985-01-01

    The two-dimensional scattering of an electromagnetic pulse normally incident on a collection of infinitely long cylinders of arbitrary shape is considered. For E-polarization an electric field integral equation is derived that is applicable to solid cylinders and/or thin sheets, resistive and/or perfectly conducting. The contribution of the self-cell at later times is carefully analyzed. The expression obtained represents a generalization of previously known results. For an incident Gaussian pulse, numerical results are presented for surface currents and far-fields, for perfectly conducting and resistive circular cylinders and strips. A fast Fourier transform (FFT) algorithm is implemented to obtain the backscattering radar cross section, which is in good agreement with results obtained from either exact continuous wave (CW) solutions or the method of moments.

  3. Modeling treatment-resistant depression.

    PubMed

    Samuels, Benjamin Adam; Leonardo, Eduardo David; Gadient, Reto; Williams, Amanda; Zhou, Jin; David, Denis J; Gardier, Alain Michel; Wong, Erik H F; Hen, René

    2011-09-01

    Depression is a polygenic and highly complex psychiatric disorder that is currently a major burden on society. Depression is highly heterogeneous in presentation and frequently exhibits high comorbidity with other psychiatric and somatic disorders. Commonly used treatments, such as selective serotonin reuptake inhibitors (SSRIs), are not ideal since only a subset of patients achieve remission. In addition, the reason why some individuals respond to SSRIs while others don't are unknown. Here we begin to ask what the basis of treatment resistance is, and propose new strategies to model this phenomenon in animals. We focus specifically on animal models that offer the appropriate framework to study treatment resistance with face, construct and predictive validity. PMID:21356220

  4. Analysis of panel dent resistance

    NASA Technical Reports Server (NTRS)

    Ni, C. M.

    1976-01-01

    An analytical technique for elastic-plastic deformation of panels was developed, which is employed to analyze the denting mechanisms of panels resulting from point projectile impacts and impulsive loadings. The correlations of analytical results with the experimental measurements are considered quite satisfactory. The effect of elastic springback on the dent resistance analysis is found to be very significant for the panel (122 cm x 60.9 cm x 0.076 cm) subjected to a point projectile impact at 16.45 m/sec. While the amount of springback decreases as the loading speed increases, the effect due to the strain rate hardening of material, such as low carbon steel, becomes more dominant and is demonstrated in the analysis of dent resistance of a rectangular steel plate impulsively loaded.

  5. Pharmacotherapy for multidrug resistant tuberculosis

    PubMed Central

    Chhabra, Naveen; Aseri, M. L.; Dixit, Ramakant; Gaur, S.

    2012-01-01

    The current global concern in the treatment of tuberculosis (TB) is the emergence of resistance to the two most potent drugs namely, isoniazid and rifampicin. Emergence of multidrug resistance tuberculosis (MDR-TB) is now a health problem faced by most of the developing countries as well as developed countries across the globe. MDR-TB is a man-made disease that is caused by improper treatment, inadequate drug supplies, and poor patient supervision. HIV infection and AIDS have been implicated as important cause for this. The review of a published literature suggests that the most powerful predictor of treatment of MDR-TB is a history of treatment of TB. Although the treatment is efficacious, there are also a number of adverse effects caused by drugs used in the treatment of MDR-TB. PMID:22629081

  6. [Biofilms, tolerance and antimicrobial resistance].

    PubMed

    Bahar, Gül

    2002-01-01

    Virtually every surface examined in natural, industrial and pathogenic ecosystems are colonized by biofilms consisting of adherent populations of microorganisms surrounded with a glycocalyx matrix. The development of biofilms has important economic and medical consequences. The development and use of a broad range of medical devices made us recognize a variety of infections caused by microorganisms that were regarded previously as harmless. Infections caused by biofilms are difficult to eradicate with antimicrobial treatment, and in-vitro susceptibility tests show significant resistance of biofilm cells to be killed. Advances in our understanding of biofilm formation can assist in the development of novel strategies for the prevention and treatment of infections caused by biofilms. In this review article, structures, general properties and antimicrobial resistance mechanisms of biofilms were discussed under the light of recent literature. PMID:12838670

  7. Cycloheximide resistance of Physarum polycephalum

    SciTech Connect

    Evans, T.E.; Evans, H.H.

    1980-08-01

    In the presence of cycloheximide, wild-type plasmodia of Physarum polycephalum exhibit an immediate decrease in deoxyribonucleic acid synthesis, a reduction in the incorporation of (/sup 3/H)thymidine into thymidine triphosphate, and an increase in the level of thymidine triphosphate, as well as a decrease in protein synthesis. In this study, we have utilized a cycloheximide-resistant (Cyc/sup r/) amoebic strain selected from a population of cells mutagenized with nitrosoguanidine.

  8. Systems biology of diuretic resistance

    PubMed Central

    Knepper, Mark A.

    2015-01-01

    Diuretics are commonly used to treat hypertension and extracellular fluid volume expansion. However, the development of compensatory responses in the kidney limits the benefit of this class of drugs. In this issue of the JCI, Grimm and colleagues use a systems biology approach in mice lacking the kinase SPAK and unravel a complex mechanism that explains thiazide diuretic resistance. The overall process involves interactions among six different cell types in the kidney. PMID:25893597

  9. Coercion-Resistant Electronic Elections

    NASA Astrophysics Data System (ADS)

    Juels, Ari; Catalano, Dario; Jakobsson, Markus

    We introduce a model for electronic election schemes that involves a more powerful adversary than previous work. In particular, we allow the adversary to demand of coerced voters that they vote in a particular manner, abstain from voting, or even disclose their secret keys. We define a scheme to be coercion-resistant if it is infeasible for the adversary to determine whether a coerced voter complies with the demands.

  10. Understanding Resistance to Combination Chemotherapy

    PubMed Central

    Pritchard, Justin R.; Lauffenburger, Douglas A.; Hemann, Michael T.

    2014-01-01

    Summary The current clinical application of combination chemotherapy is guided by a historically successful set of practices that were developed by basic and clinical researchers 50-60 years ago. Thus, in order to understand how emerging approaches to drug development might aid the creation of new therapeutic combinations, it is critical to understand the defining principles underlying classic combination therapy and the original experimental rationales behind them. One such principle is that the use of combination therapies with independent mechanisms of action can minimize the evolution of drug resistance. Another is that in order to kill sufficient cancer cells to cure a patient, multiple drugs must be delivered at their maximum tolerated dose – a condition that allows for enhanced cancer cell killing with manageable toxicity. In light of these models, we aim to explore recent genomic evidence underlying the mechanisms of resistance to the combination regimens constructed on these principles. Interestingly, we find that emerging genomic evidence contradicts some of the rationales of early practitioners in developing commonly used drug regimens. However, we also find that the addition of recent targeted therapies has yet to change the current principles underlying the construction of anti-cancer combinatorial regimens, nor have they made substantial inroads into the treatment of most cancers. We suggest that emerging systems/network biology approaches have an immense opportunity to impact the rational development of successful drug regimens. Specifically, by examining drug combinations in multivariate ways, next generation combination therapies can be constructed with a clear understanding of how mechanisms of resistance to multi-drug regimens differ from single agent resistance. PMID:23164555

  11. Calibration of Germanium Resistance Thermometers

    NASA Technical Reports Server (NTRS)

    Ladner, D.; Urban, E.; Mason, F. C.

    1987-01-01

    Largely completed thermometer-calibration cryostat and probe allows six germanium resistance thermometers to be calibrated at one time at superfluid-helium temperatures. In experiments involving several such thermometers, use of this calibration apparatus results in substantial cost savings. Cryostat maintains temperature less than 2.17 K through controlled evaporation and removal of liquid helium from Dewar. Probe holds thermometers to be calibrated and applies small amount of heat as needed to maintain precise temperature below 2.17 K.

  12. EUV Resists: Illuminating the challenges

    SciTech Connect

    Naulleau, Patrick; Anderson, Christopher; George, Simi

    2011-06-01

    As extreme ultraviolet (EUV) lithography enters the commercialization phase with potential introduction at the 3x nm half-pitch node in 2013, the attention of advanced EUV resist research has turned to addressing patterning at 16-nm half pitch and below. Whereas line-edge roughness is the primary concern at 2x half pitch and larger, research at the 16-nm half pitch level is uncovering broader.

  13. Immunoglobulin Resistance in Kawasaki Disease

    PubMed Central

    Hartas, Georgios A.; Hashmi, Syed Shahrukh; Pham-Peyton, Chi; Tsounias, Emmanouil; Bricker, John T.

    2015-01-01

    Background: The aim of this study was to identify risk factors for immunoglobulin resistance, including clinical symptoms such as arthritis and the pH of intravenous immunoglobulin. Methods: The data of children with Kawasaki disease who had received immunoglobulin were evaluated. Data regarding the brand of immunoglobulin administered were abstracted from the pharmacy records. Results: Eighty consecutive children with Kawasaki disease were evaluated (Mdnage=28 months, 66% male). The prevalence of immunoglobulin resistance was 30%. Arthritis was a presenting symptom in the acute phase of Kawasaki disease in 8% (6/80, all male) and was seen in significant association with immunoglobulin resistance in comparison to those without arthritis (16.7% vs. 0.2%, p=0.008). Next, the immunoglobulin brand types were divided into two groups: the relatively high pH group (n=16), including Carimune (pH 6.6±0.2), and the low pH group (n=63), including Gamunex (pH 4–4.5) or Privigen (pH 4.6–5). Overall, no significant difference in immunoglobulin responsiveness was found between the low pH and the high pH groups (73% vs. 56%, p=0.193), although the low pH group showed a trend toward a larger decrease in erythrocyte sedimentation rate (p=0.048), lower steroid use (p=0.054), and lower coronary involvement (p=0.08) than those in the high pH group. Conclusions: Children presenting with arthritis in the acute phase of Kawasaki disease may be at risk for immunoglobulin resistance. PMID:25852966

  14. Genetic resistance to disease in cattle

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic resistance to disease in cattle is a popular topic of scientific discussion and research. Justifications for genetic selection for disease resistance include the need for additional approaches to counter antibiotic and therapeutic resistance by pathogens, consumer demand for zero drug residu...

  15. The determinants of the antibiotic resistance process

    PubMed Central

    Franco, Beatriz Espinosa; Altagracia Martínez, Marina; Sánchez Rodríguez, Martha A; Wertheimer, Albert I

    2009-01-01

    Background: The use of antibiotic drugs triggers a complex interaction involving many biological, sociological, and psychological determinants. Resistance to antibiotics is a serious worldwide problem which is increasing and has implications for morbidity, mortality, and health care both in hospitals and in the community. Objectives: To analyze current research on the determinants of antibiotic resistance and comprehensively review the main factors in the process of resistance in order to aid our understanding and assessment of this problem. Methods: We conducted a MedLine search using the key words “determinants”, “antibiotic”, and “antibiotic resistance” to identify publications between 1995 and 2007 on the determinants of antibiotic resistance. Publications that did not address the determinants of antibiotic resistance were excluded. Results: The process and determinants of antibiotic resistance are described, beginning with the development of antibiotics, resistance and the mechanisms of resistance, sociocultural determinants of resistance, the consequences of antibiotic resistance, and alternative measures proposed to combat antibiotic resistance. Conclusions: Analysis of the published literature identified the main determinants of antibiotic resistance as irrational use of antibiotics in humans and animal species, insufficient patient education when antibiotics are prescribed, lack of guidelines for treatment and control of infections, lack of scientific information for physicians on the rational use of antibiotics, and lack of official government policy on the rational use of antibiotics in public and private hospitals. PMID:21694883

  16. Identification of Rotylenchulus reniformis resistant Glycine lines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Identification of resistance to reniform nematode (Rotylenchulus reniformis) is the first step in developing resistant soybean (Glycine max) cultivars that will benefit growers in the Mid South. This study was conducted to identify soybean (G. max and G. soja) lines with resistance to this pathogen....

  17. 30 CFR 14.20 - Flame resistance.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... test determined by MSHA to be equivalent under 30 CFR §§ 6.20 and 14.4(e). ... MINING PRODUCTS REQUIREMENTS FOR THE APPROVAL OF FLAME-RESISTANT CONVEYOR BELTS Technical Requirements § 14.20 Flame resistance. Conveyor belts for use in underground coal mines must be flame-resistant...

  18. 30 CFR 14.20 - Flame resistance.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... test determined by MSHA to be equivalent under 30 CFR §§ 6.20 and 14.4(e). ... MINING PRODUCTS REQUIREMENTS FOR THE APPROVAL OF FLAME-RESISTANT CONVEYOR BELTS Technical Requirements § 14.20 Flame resistance. Conveyor belts for use in underground coal mines must be flame-resistant...

  19. A Simple Technique for High Resistance Measurement

    ERIC Educational Resources Information Center

    Aguilar, Horacio Munguia; Landin, Ramon Ochoa

    2012-01-01

    A simple electronic system for the measurement of high values of resistance is shown. This system allows the measurement of resistance in the range of a few megohm up to 10[superscript 9] [omega]. We have used this system for the evaluation of CdS thin film resistance, but other practical uses in the basic physics laboratory are presented.…

  20. Antimicrobial resistance of enterococci from animals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There is increasing concern over antimicrobial resistance in bacteria of animal and human origin including the possibility of transfer of resistance genes between animal to human bacteria, particularly, those that may be pathogenic. The reported increases in resistance are thought to result from ant...

  1. Meeting Client Resistance and Reactance with Reverence.

    ERIC Educational Resources Information Center

    Cowan, Eric W.; Presbury, Jack H.

    2000-01-01

    Explores the meaning and function of client resistance in counseling from various theoretical orientations. A relational model of resistance is offered that redefines traditional formulations and has implications for clinical treatment. A vignette illustrates that the counselor's contribution to the emergence of client resistance is a relevant…

  2. MULTIPLE DRUG RESISTANCE: TRENDS AND IMPLICATIONS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antimicrobial resistance (AR) has emerged as a global problem. Although AR occurs shortly after the introduction and use of an antimicrobial, resistance levels vary over time. Historically, antimicrobials were regarded as wonder drugs and for years, when resistance to a single antimicrobial occurr...

  3. Resistance and Subversion in Everyday Life.

    ERIC Educational Resources Information Center

    Turiel, Elliot

    2003-01-01

    Argues that resistance and subversion are part of life and integral to development in most cultures. Notes that many theories of social and moral development do not account for resistance or view it as anti-social. Demonstrates that social conflict and resistance based on moral aims occur in childhood, adolescence, and adulthood. (CAJ)

  4. Antibiotic resistance in soil and water environments.

    PubMed

    Esiobu, Nwadiuto; Armenta, Lisa; Ike, Joseph

    2002-06-01

    Seven locations were screened for antibiotic-resistant bacteria using a modified agar dilution technique. Isolates resistant to high levels of antibiotics were screened for r plasmids. Low-level resistance (25 micro g x ml(-1)) was widespread for ampicillin, penicillin, tetracycline, vancomycin and streptomycin but not for kanamycin. Resistant populations dropped sharply at high antibiotic levels, suggesting that intrinsic non-emergent mechanisms were responsible for the multiple drug resistance exhibited at low doses. Dairy farm manure contained significantly (P < 0.01) more (%) resistant bacteria than the other sites. Bacteria isolated from a dairy water canal, a lake by a hospital and a residential garden (fertilized by farm manure) displayed resistance frequencies of 77, 75 and 70%, respectively. Incidence of tetracycline resistance was most prevalent at 47-89% of total bacteria. Out of 200 representative isolates analyzed, Pseudomonas, Enterococcus-like bacteria, Enterobacter and Burkholderia species constituted the dominant reservoirs of resistance at high drug levels (50-170 micro g x ml(-1)). Plasmids were detected in only 29% (58) of these bacteria with tetracycline resistance accounting for 65% of the plasmid pool. Overall, resistance trends correlated to the abundance and type of bacterial species present in the habitat. Environmental reservoirs of resistance include opportunistic pathogens and constitute some public health concern. PMID:12396530

  5. New approaches to rust resistance in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ug99 is new race of Puccinia graminis that is virulent on most of the widely deployed stem rust resistance genes from wheat, posing a serious threat to global wheat production. Sr35, a resistance gene from Triticum monococcum, confers resistance to Ug99 and all related Ug99-derived stem rust races i...

  6. Mechanisms of Resistance to Grapevine Powdery Mildew

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although all high quality Vitis vinifera cultivars are highly susceptible to powdery mildew, current efforts show promise for the identification or modulation of resistance within the species and for continued introgression of resistance from resistant accessions of wild Vitis spp. Examination of t...

  7. Resistance Gene Analogs in Cherries (Prunus spp.)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Genetic studies have shown that NBS-LRR Resistance Gene Analogs (RGAs) tend to occur in clusters and often map to major resistances gene or QTL. The identification and use of specific RGAs as molecular markers among plant material displaying differential resistance phenotypes has the potential to di...

  8. Pseudomonas Aeruginosa: Resistance to the Max

    PubMed Central

    Poole, Keith

    2011-01-01

    Pseudomonas aeruginosa is intrinsically resistant to a variety of antimicrobials and can develop resistance during anti-pseudomonal chemotherapy both of which compromise treatment of infections caused by this organism. Resistance to multiple classes of antimicrobials (multidrug resistance) in particular is increasingly common in P. aeruginosa, with a number of reports of pan-resistant isolates treatable with a single agent, colistin. Acquired resistance in this organism is multifactorial and attributable to chromosomal mutations and the acquisition of resistance genes via horizontal gene transfer. Mutational changes impacting resistance include upregulation of multidrug efflux systems to promote antimicrobial expulsion, derepression of ampC, AmpC alterations that expand the enzyme's substrate specificity (i.e., extended-spectrum AmpC), alterations to outer membrane permeability to limit antimicrobial entry and alterations to antimicrobial targets. Acquired mechanisms contributing to resistance in P. aeruginosa include β-lactamases, notably the extended-spectrum β-lactamases and the carbapenemases that hydrolyze most β-lactams, aminoglycoside-modifying enzymes, and 16S rRNA methylases that provide high-level pan-aminoglycoside resistance. The organism's propensity to grow in vivo as antimicrobial-tolerant biofilms and the occurrence of hypermutator strains that yield antimicrobial resistant mutants at higher frequency also compromise anti-pseudomonal chemotherapy. With limited therapeutic options and increasing resistance will the untreatable P. aeruginosa infection soon be upon us? PMID:21747788

  9. Streptococcus pneumoniae Isolates Resistant to Telithromycin

    PubMed Central

    Rantala, M.; Haanperä-Heikkinen, M.; Lindgren, M.; Seppälä, H.; Huovinen, P.; Jalava, J.

    2006-01-01

    The telithromycin susceptibility of 210 erythromycin-resistant pneumococci was tested with the agar diffusion method. Twenty-six erm(B)-positive isolates showed heterogeneous resistance to telithromycin, which was manifested by the presence of colonies inside the inhibition zone. When these cells were cultured and tested, they showed stable, homogeneous, and high-level resistance to telithromycin. PMID:16641460

  10. Role of multidrug resistance in photodynamic therapy

    NASA Astrophysics Data System (ADS)

    Diddens, Heyke C.

    1992-06-01

    Multidrug resistance in cancer chemotherapy is a well established phenomenon. One of the most common phenotypical changes in acquired or intrinsic multidrug resistance in human tumor cells is the overexpression of the mdrl gene product P-glycoprotein, which acts as an active efflux pump. Increased levels of P-glycoprotein are associated with resistance to a variety of anticancer drugs commonly used in tumor chemotherapy like anthracyclins, vinca- alcaloids, epipodophyllotoxins or actinomycin D. We investigated the efficacy or photodynamic therapy in the treatment of tumor cells expressing the multidrug resistance phenotype. Our data show that multidrug resistant cells are highly cross resistant to the phototoxic stain rhodamine 123 but exhibit only low degrees of cross resistance (2 - 3 -folds) to the photosensitizers Photosan-3, Clorin-2, methylene blue and meso-tetra (4- sulfonatophenyl) porphine (TPPS4). Resistance is associated with a decrease in intracellular accumulation of the photosensitizer. Verapamil, a membrane active compound known to enhance drug sensitivity in multidrug resistant cells by inhibition of P-glycoprotein, also increases phototoxicity in multidrug resistant cells. Our results imply that tumors expressing the multidrug resistance phenotype might fail to respond to photochemotherapy with rhodamine 123. On the other hand, multidrug resistance may not play an important role in photodynamic therapy with Photosan-3, Chlorin-2, methylene blue or TPPS4.

  11. A fractal-like resistive network

    NASA Astrophysics Data System (ADS)

    Saggese, A.; De Luca, R.

    2014-11-01

    The equivalent resistance of a fractal-like network is calculated by means of approaches similar to those employed in defining the equivalent resistance of an infinite ladder. Starting from an elementary triangular circuit, a fractal-like network, named after Saggese, is developed. The equivalent resistance of finite approximations of this network is measured, and the didactical implications of the model are highlighted.

  12. Breeding for sugarcane borer resistance in Louisiana

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Growing resistant varieties is a key component of the Integrated Pest Management Program for managing the sugarcane borer in Louisiana; however, the release of resistant varieties to growers is sporadic. The challenge facing the Louisiana industry is how to increase resistance in its varieties witho...

  13. Mitochondrial efficiency and insulin resistance.

    PubMed

    Crescenzo, Raffaella; Bianco, Francesca; Mazzoli, Arianna; Giacco, Antonia; Liverini, Giovanna; Iossa, Susanna

    2014-01-01

    Insulin resistance, "a relative impairment in the ability of insulin to exert its effects on glucose, protein and lipid metabolism in target tissues," has many detrimental effects on metabolism and is strongly correlated to deposition of lipids in non-adipose tissues. Mitochondria are the main cellular sites devoted to ATP production and fatty acid oxidation. Therefore, a role for mitochondrial dysfunction in the onset of skeletal muscle insulin resistance has been proposed and many studies have dealt with possible alteration in mitochondrial function in obesity and diabetes, both in humans and animal models. Data reporting evidence of mitochondrial dysfunction in type two diabetes mellitus are numerous, even though the issue that this reduced mitochondrial function is causal in the development of the disease is not yet solved, also because a variety of parameters have been used in the studies carried out on this subject. By assessing the alterations in mitochondrial efficiency as well as the impact of this parameter on metabolic homeostasis of skeletal muscle cells, we have obtained results that allow us to suggest that an increase in mitochondrial efficiency precedes and therefore can contribute to the development of high-fat-induced insulin resistance in skeletal muscle. PMID:25601841

  14. Direct measurement of turbulent resistivity

    NASA Astrophysics Data System (ADS)

    Nornberg, M. D.

    2013-10-01

    We have directly measured the vector turbulent emf in a two-vortex flow of liquid sodium in the Madison Dynamo Experiment. Using a novel probe design, we simultaneously measure magnetic and flow fluctuations to determine their correlated effect on mean-field induction. Through our electromagnetic model for the flow-induced mean magnetic field, constrained by measurements throughout the flow, we construct the vector mean current density at the probe location. With this information we are able to construct the mean-field model for the α and β-effect terms of the turbulent emf and compare them with the direct measurement of the time averaged correlated fluctuations. The measured turbulent emf is anti-parallel with the mean current and is almost entirely described by an enhanced resistivity. The residual turbulent resistivity presents a difficulty for establishing the onset of the kinematic dynamo in a laboratory turbulent flow in that the effective magnetic Reynolds number is reduced making it more difficult to exceed the critical Rm . We have demonstrated that this enhanced resistivity can be mitigated by eliminating the largest-scale eddies. By tailoring the large-scale flow, we have achieved flows operating near threshold for dynamo self-excitation.

  15. Turbulent resistivity, diffusion and heating

    NASA Technical Reports Server (NTRS)

    Fried, B. D.; Kennel, C. F.; Mackenzie, K.; Coroniti, F. V.; Kindel, J. M.; Stenzel, R.; Taylor, R. J.; White, R.; Wong, A. Y.; Bernstein, W.

    1971-01-01

    Experimental and theoretical studies are reported on ion acoustic and ion cyclotron turbulence and their roles in anomalous resistivity, viscosity, diffusion and heating and in the structure of collisionless electrostatic shocks. Resistance due to ion acoustic turbulence has been observed in experiments with a streaming cesium plasma in which electron current, potential rise due to turbulent resistivity, spectrum of unstable ion acoustic waves, and associated electron heating were all measured directly. Kinetic theory calculations for an expanding, unstable plasma, give results in agreement with the experiment. In a strong magnetic field, with T sub e/T sub i approximately 1 and current densities typical for present Tokomaks, the plasma is stable to ion acoustic but unstable to current driven electrostatic ion cyclotron waves. Relevant characteristics of these waves are calculated and it is shown that for ion, beta greater than m sub e/m sub i, the electromagnetic ion cyclotron wave has a lower instability threshold than the electrostatic one. However, when ion acoustic turbulence is present experiments with double plasma devices show rapid anomalous heating of an ion beam streaming through a plasma.

  16. Plasmid-mediated quinolone resistance

    PubMed Central

    Jacoby, George A.; Strahilevitz, Jacob; Hooper, David C.

    2014-01-01

    Summary Three mechanisms for plasmid-mediated quinolone resistance (PMQR) have been discovered since 1998. Plasmid genes qnrA, qnrB, qnrC, qnrD, qnrS, and qnrVC code for proteins of the pentapeptide repeat family that protects DNA gyrase and topoisomerase IV from quinolone inhibition. The qnr genes appear to have been acquired from chromosomal genes in aquatic bacteria, are usually associated with mobilizing or transposable elements on plasmids, and are often incorporated into sul1-type integrons. The second plasmid-mediated mechanism involves acetylation of quinolones with an appropriate amino nitrogen target by a variant of the common aminoglycoside acetyltransferase AAC(6′)-Ib. The third mechanism is enhanced efflux produced by plasmid genes for pumps QepAB and OqxAB. PMQR has been found in clinical and environmental isolates around the world and appears to be spreading. The plasmid-mediated mechanisms provide only low-level resistance that by itself does not exceed the clinical breakpoint for susceptibility but nonetheless facilitates selection of higher-level resistance and makes infection by pathogens containing PMQR harder to treat. PMID:25584197

  17. Unpowered wireless analog resistance sensor

    NASA Astrophysics Data System (ADS)

    Andringa, Matthew M.; Neikirk, Dean P.; Wood, Sharon L.

    2004-07-01

    Our society depends heavily on a network of buildings, bridges and roadways. In order to properly maintain this civil infrastructure and avoid damage and costly repairs due to structural failure, it is necessary to monitor the health of these structures. Sensors must frequently be placed in inaccessible locations under harsh conditions and should ideally last the lifetime of the structure the sensors are monitoring. This paper presents the development of a low cost, passive, un-powered wireless analog resistance sensor. The sensor was originally designed for monitoring corrosion in concrete, but there are many other potential applications including remote temperature monitoring, embedded accelerometers, and embedded strain gauges. The passive wireless nature makes the sensor ideally suited for embedding in inaccessible locations under harsh conditions. The sensor consists of a resonant inductor-capacitor circuit containing a resistive transducer. The sensor is interrogated by measuring the impedance through a remote, magnetically coupled reader loop. The width of the resonance is directly related to the resistance of the transducer. The sensor has been simulated under a variety of conditions using a circuit model and compared to actual test sensors built and evaluated in the laboratory.

  18. Barrier/Cu contact resistivity

    SciTech Connect

    Reid, J.S.; Nicolet, M.A.; Angyal, M.S.; Lilienfeld, D.; Shacham-Diamand, Y.; Smith, P.M.

    1995-10-17

    The specific contact resistivity of Cu with ({alpha} + {beta})-Ta, TiN, {alpha}-W, and amorphous-Ta{sub 36}Si{sub 14}N{sub 50} barrier films is measured using a novel four-point-probe approach. Geometrically, the test structures consist of colinear sets of W-plugs to act as current and voltage probes that contact the bottom of a planar Cu/barrier/Cu stack. Underlying Al interconnects link the plugs to the current source and voltmeter. The center-to-center distance of the probes ranges from 3 to 200 {micro}m. Using a relation developed by Vu et al., a contact resistivity of roughly 7 {times} 10{sup {minus}9} {Omega} cm{sup 2} is obtained for all tested barrier/Cu combinations. By reflective-mode small-angle X-ray scattering, the similarity in contact resistivity among the barrier films may be related to interfacial impurities absorbed from the deposition process.

  19. Resistant multiple sparse canonical correlation.

    PubMed

    Coleman, Jacob; Replogle, Joseph; Chandler, Gabriel; Hardin, Johanna

    2016-04-01

    Canonical correlation analysis (CCA) is a multivariate technique that takes two datasets and forms the most highly correlated possible pairs of linear combinations between them. Each subsequent pair of linear combinations is orthogonal to the preceding pair, meaning that new information is gleaned from each pair. By looking at the magnitude of coefficient values, we can find out which variables can be grouped together, thus better understanding multiple interactions that are otherwise difficult to compute or grasp intuitively. CCA appears to have quite powerful applications to high-throughput data, as we can use it to discover, for example, relationships between gene expression and gene copy number variation. One of the biggest problems of CCA is that the number of variables (often upwards of 10,000) makes biological interpretation of linear combinations nearly impossible. To limit variable output, we have employed a method known as sparse canonical correlation analysis (SCCA), while adding estimation which is resistant to extreme observations or other types of deviant data. In this paper, we have demonstrated the success of resistant estimation in variable selection using SCCA. Additionally, we have used SCCA to find multiple canonical pairs for extended knowledge about the datasets at hand. Again, using resistant estimators provided more accurate estimates than standard estimators in the multiple canonical correlation setting. R code is available and documented at https://github.com/hardin47/rmscca. PMID:26963062

  20. [Proteins in cancer multidrug resistance].

    PubMed

    Popęda, Marta; Płuciennik, Elżbieta; Bednarek, Andrzej K

    2014-01-01

    Multidrug Resistance (MDR) is defined as insensitivity to administered medicines that are structurally unrelated and have different molecular targets. Cancers possess numerous mechanisms of drug resistance, involving various aspects of cell biology. A pivotal role in this phenomenon is played by proteins--enzymatic or structural parts of the cell. Membrane transporters, including the main members of ABC protein family--P-gp, MRP1 and BCRP, as well as LRP, which builds structure of vaults, determine the multidrug-resistant phenotype by decreasing drug concentration within the cell or modifying its distribution to intracellular compartments. The π isoform of protein enzyme--glutathione S-transferase (GSTP-1), is responsible for excessive intensity of detoxification of cytostatics. A common example of altered drug target site that does not respond to chemotherapy is topoisomerase II α (TopoIIa). Alterations of programmed cell death result from expression of metallothionein (MT)--inhibitor of the process, and cytokeratin 18 (CK18), which, if in high concentration, also prevents apoptosis of cells. Several methods of decreasing activity of these proteins have been developed, aiming to overcome MDR in cancer cells. However, for a variety of reasons, their clinical suitability is still very low, leading to continuous increase in death rate among patients. This paper presents current state of knowledge on the most important examples of proteins responsible for MDR of cancer cells and molecular mechanisms of their action. PMID:24864112

  1. RESISTIVE SOLUTIONS FOR PULSAR MAGNETOSPHERES

    SciTech Connect

    Li, Jason; Spitkovsky, Anatoly; Tchekhovskoy, Alexander

    2012-02-10

    The current state of the art in the modeling of pulsar magnetospheres invokes either the vacuum or force-free limits for the magnetospheric plasma. Neither of these limits can simultaneously account for both the plasma currents and the accelerating electric fields that are needed to explain the morphology and spectra of high-energy emission from pulsars. To better understand the structure of such magnetospheres, we combine accelerating fields and force-free solutions by considering models of magnetospheres filled with resistive plasma. We formulate Ohm's law in the minimal velocity fluid frame and construct a family of resistive solutions that smoothly bridges the gap between the vacuum and the force-free magnetosphere solutions. The spin-down luminosity, open field line potential drop, and the fraction of open field lines all transition between the vacuum and force-free values as the plasma conductivity varies from zero to infinity. For fixed inclination angle, we find that the spin-down luminosity depends linearly on the open field line potential drop. We consider the implications of our resistive solutions for the spin-down of intermittent pulsars and sub-pulse drift phenomena in radio pulsars.

  2. Resistance of a water spark.

    SciTech Connect

    Warne, Larry Kevin; Jorgenson, Roy Eberhardt; Lehr, Jane Marie

    2005-11-01

    The later time phase of electrical breakdown in water is investigated for the purpose of improving understanding of the discharge characteristics. One dimensional simulations in addition to a zero dimensional lumped model are used to study the spark discharge. The goal is to provide better electrical models for water switches used in the pulse compression section of pulsed power systems. It is found that temperatures in the discharge channel under representative drive conditions, and assuming small initial radii from earlier phases of development, reach levels that are as much as an order of magnitude larger than those used to model discharges in atmospheric gases. This increased temperature coupled with a more rapidly rising conductivity with temperature than in air result in a decreased resistance characteristic compared to preceding models. A simple modification is proposed for the existing model to enable the approximate calculation of channel temperature and incorporate the resulting conductivity increase into the electrical circuit for the discharge channel. Comparisons are made between the theoretical predictions and recent experiments at Sandia. Although present and past experiments indicated that preceding late time channel models overestimated channel resistance, the calculations in this report seem to underestimate the resistance relative to recent experiments. Some possible reasons for this discrepancy are discussed.

  3. [Antibiotic resistance--bacteria fight back].

    PubMed

    Tambić Andrasević, Arjana

    2004-01-01

    Antibiotic resistance has become one of the leading problems in modern medicine. Resistance to antibiotics emerges in bacteria due to genetic mutations and consecutive selection of resistant mutants through selective pressure of antibiotics present in large amounts in soil, plants, animals and humans. Exchange of genetic material coding for resistance is possible even between unrelated organisms and further promotes the spread of resistance. Constantly evolving resistance mechanisms force experts to redefine breakpoint concentrations and interpretation of in vitro antibiotic sensitivity testing. Developing new antimicrobial agents does not seem to be enough to keep up pace with ever changing bacteria. Using antibiotics prudently and developing new approaches to the treatment of infections is vital for the future. The European Antimicrobial Resistance Surveillance System (EARSS) data clearly show that Scandinavian countries and The Netherlands have the lowest rates of resistance, while Southern and Eastern European countries have the highest prevalence of resistance. This is linked to the European Surveillance of Antimicrobial Consumption (ESAC) data that show very low consumption of antibiotics in Scandinavian countries and The Netherlands. Compliance with strict infection control policies related to multidrug resistant organisms is also high in these countries. Although it is important to be aware of the resistance problems worldwide, rational use of antibiotics should be based on the knowledge of local resistance patterns in common pathogens. Since 1996 there is a continuous surveillance of resistance in Croatia through the Croatian Committee for Antibiotic Resistance Surveillance. There is a particular concern about the rising penicillin and macrolide resistance in pneumococci. In Croatia, data for 2002 suggest that resistance to penicillin in pneumococci was 30% (low level) and 2% (high level). Among invasive isolates, 19% had reduced susceptibility to

  4. Youth, Social Networking, and Resistance: A Case Study on a Multidimensional Approach to Resistance

    ERIC Educational Resources Information Center

    Scozzaro, David

    2011-01-01

    This exploratory case study focused on youth and resistance that was aided by the use of technology. The combination of resistance and technology expanded a multidimensional framework and leads to new insight into transformative resistance. This study examined the framework of transformative resistance based on Solorzano and Delgado Bernal's…

  5. Novel resistance functions uncovered using functional metagenomic investigations of resistance reservoirs

    PubMed Central

    Pehrsson, Erica C.; Forsberg, Kevin J.; Gibson, Molly K.; Ahmadi, Sara; Dantas, Gautam

    2013-01-01

    Rates of infection with antibiotic-resistant bacteria have increased precipitously over the past several decades, with far-reaching healthcare and societal costs. Recent evidence has established a link between antibiotic resistance genes in human pathogens and those found in non-pathogenic, commensal, and environmental organisms, prompting deeper investigation of natural and human-associated reservoirs of antibiotic resistance. Functional metagenomic selections, in which shotgun-cloned DNA fragments are selected for their ability to confer survival to an indicator host, have been increasingly applied to the characterization of many antibiotic resistance reservoirs. These experiments have demonstrated that antibiotic resistance genes are highly diverse and widely distributed, many times bearing little to no similarity to known sequences. Through unbiased selections for survival to antibiotic exposure, functional metagenomics can improve annotations by reducing the discovery of false-positive resistance and by allowing for the identification of previously unrecognizable resistance genes. In this review, we summarize the novel resistance functions uncovered using functional metagenomic investigations of natural and human-impacted resistance reservoirs. Examples of novel antibiotic resistance genes include those highly divergent from known sequences, those for which sequence is entirely unable to predict resistance function, bifunctional resistance genes, and those with unconventional, atypical resistance mechanisms. Overcoming antibiotic resistance in the clinic will require a better understanding of existing resistance reservoirs and the dissemination networks that govern horizontal gene exchange, informing best practices to limit the spread of resistance-conferring genes to human pathogens. PMID:23760651

  6. Prevalence of pyrazinamide resistance across the spectrum of drug resistant phenotypes of Mycobacterium tuberculosis.

    PubMed

    Whitfield, Michael G; Streicher, Elizabeth M; Dolby, Tania; Simpson, John A; Sampson, Samantha L; Van Helden, Paul D; Van Rie, Annelies; Warren, Robin M

    2016-07-01

    Pyrazinamide resistance is largely unknown in the spectrum of drug resistant phenotypes. We summarize data on PZA resistance in clinical isolates from South Africa. PZA DST should be performed when considering its inclusion in treatment of patients with rifampicin-resistant TB or MDR-TB. PMID:27450014

  7. Phenotypic- and Genotypic-Resistance Detection for Adaptive Resistance Management in Tetranychus urticae Koch

    PubMed Central

    Kwon, Deok Ho; Kang, Taek-Jun; Kim, Young Ho; Lee, Si Hyeock

    2015-01-01

    Rapid resistance detection is necessary for the adaptive management of acaricide-resistant populations of Tetranychus urticae. Detection of phenotypic and genotypic resistance was conducted by employing residual contact vial bioassay (RCV) and quantitative sequencing (QS) methods, respectively. RCV was useful for detecting the acaricide resistance levels of T. urticae, particularly for on-site resistance detection; however, it was only applicable for rapid-acting acaricides (12 out of 19 tested acaricides). QS was effective for determining the frequencies of resistance alleles on a population basis, which corresponded to 12 nonsynonymous point mutations associated with target-site resistance to five types of acaricides [organophosphates (monocrotophos, pirimiphos-methyl, dimethoate and chlorpyrifos), pyrethroids (fenpropathrin and bifenthrin), abamectin, bifenazate and etoxazole]. Most field-collected mites exhibited high levels of multiple resistance, as determined by RCV and QS data, suggesting the seriousness of their current acaricide resistance status in rose cultivation areas in Korea. The correlation analyses revealed moderate to high levels of positive relationships between the resistance allele frequencies and the actual resistance levels in only five of the acaricides evaluated, which limits the general application of allele frequency as a direct indicator for estimating actual resistance levels. Nevertheless, the resistance allele frequency data alone allowed for the evaluation of the genetic resistance potential and background of test mite populations. The combined use of RCV and QS provides basic information on resistance levels, which is essential for choosing appropriate acaricides for the management of resistant T. urticae. PMID:26545209

  8. [Multidrug resistance (MDR) in oncology].

    PubMed

    Souvirón Rodríguez, A; Ruiz Gómez, M J; Morales Moreno, J A; Martínez Morillo, M

    1997-03-01

    Multidrug resistance or mdr is a frequent phenomenon for which tumor cells can develop, in only one step, cross-resistance to a different anticancer drugs such as antibiotics, vinca alkaloids and podophylotoxins. This is due to an extrusion of drugs out of the cells, since it is interrelated with the decrease of the intracellular concentration of the drug, compared to sensitive cells. This phenomeno of multidrug resistance (mdr) is considered one of the principal causes of failure in quimiotherapic treatment of cancer, and is associated in many cases to an hyperexpression of mdr-I gene, that codifies for a high molecular weight glycoprotein (p-170) (170-180 Kdaltons), also called p-glycoprotein (pgp). Locadet it in the cellular membrane extracts, like a pump, the quimiotherapic drugs with consumption of ATP. In humans, there are two principal genes that codify for pgp: mdr-I and mdr2/3; being the most important the mdr-I gene. The structure of p-glycoprotein consists in two symmetrical halves anchored in the cellular membrane that includes three extracellular dominances each one, and on intracellular portion with the ATP binding site. Also, has got an for extracellular carbohydrates chain. It is specially important to find drugs that reverse the multidrug resistance. Chemicals such as verapamil, nifedine, quinidine and calmodulin inhibitors are joined to pgp inhibiting it. A Cyclosporine and its non-immunosuppressors derivateds such as SDZ 280-125 and SDZ PSC 833 reverse mdr. At present it is being advancing in clinical trials, but the results are not satisfactory. Most useful chemicals are verapamil, better R-verapamil and A-cyclosporine or its non-immunosuppressors derivates. Futures possibilities are grateful. From diagnostic point of view the mains are: 1. Detection of mdr-I gene. 2. Recognition of the presence of mRNA for pgp. 3. Detection of pgp by flow cytometry or western blot. 4. Immunohistochemistry with monoclonal antibodies to pgp. 5. Rhodamine 123 to

  9. The Emergence of Resistance to Fungicides

    PubMed Central

    Hobbelen, Peter H. F.; Paveley, Neil D.; van den Bosch, Frank

    2014-01-01

    Many studies exist about the selection phase of fungicide resistance evolution, where a resistant strain is present in a pathogen population and is differentially selected for by the application of fungicides. The emergence phase of the evolution of fungicide resistance - where the resistant strain is not present in the population and has to arise through mutation and subsequently invade the population - has not been studied to date. Here, we derive a model which describes the emergence of resistance in pathogen populations of crops. There are several important examples where a single mutation, affecting binding of a fungicide with the target protein, shifts the sensitivity phenotype of the resistant strain to such an extent that it cannot be controlled effectively (‘qualitative’ or ‘single-step’ resistance). The model was parameterized for this scenario for Mycosphaerella graminicola on winter wheat and used to evaluate the effect of fungicide dose rate on the time to emergence of resistance for a range of mutation probabilities, fitness costs of resistance and sensitivity levels of the resistant strain. We also evaluated the usefulness of mixing two fungicides of differing modes of action for delaying the emergence of resistance. The results suggest that it is unlikely that a resistant strain will already have emerged when a fungicide with a new mode of action is introduced. Hence, ‘anti-emergence’ strategies should be identified and implemented. For all simulated scenarios, the median emergence time of a resistant strain was affected little by changing the dose rate applied, within the range of doses typically used on commercial crops. Mixing a single-site acting fungicide with a multi-site acting fungicide delayed the emergence of resistance to the single-site component. Combining the findings with previous work on the selection phase will enable us to develop more efficient anti-resistance strategies. PMID:24658678

  10. The effects of solution resistance on electrochemical noise resistance measurements: A theoretical analysis

    SciTech Connect

    Cottis, R.A.; Turgoose, S.; Mendoza-Flores, J.

    1996-12-31

    The theoretical basis of electrochemical noise resistance measurements in the presence of significant solution resistance is examined with a simple linear circuit model. A shot noise model of the noise generation process is assumed to develop the dependence of electrochemical potential and current noise on corrosion rate, although the conclusions in respect to electrochemical noise resistance do not depend on this. It is concluded that the electrochemical noise resistance method measures essentially the same resistance as is measured by a conventional linear polarization resistance measurement, although it is found to be capable of making measurements in higher resistance systems.

  11. Analysis and modeling of resistive switching mechanisms oriented to resistive random-access memory

    NASA Astrophysics Data System (ADS)

    Huang, Da; Wu, Jun-Jie; Tang, Yu-Hua

    2013-03-01

    With the progress of the semiconductor industry, the resistive random-access memory (RAM) has drawn increasing attention. The discovery of the memristor has brought much attention to this study. Research has focused on the resistive switching characteristics of different materials and the analysis of resistive switching mechanisms. We discuss the resistive switching mechanisms of different materials in this paper and analyze the differences of those mechanisms from the view point of circuitry to establish their respective circuit models. Finally, simulations are presented. We give the prospect of using different materials in resistive RAM on account of their resistive switching mechanisms, which are applied to explain their resistive switchings.

  12. Feasibility study of resist slimming for SIT

    NASA Astrophysics Data System (ADS)

    Saulnier, Nicole; Koay, Chiew-seng; Colburn, Matthew; Hetzer, David; Cicoria, Michael; Ludwicki, Jonathan

    2013-03-01

    Wet chemical slimming of resist can enable a resist mandrel for sidewall-image transfer (SIT) by decreasing the mandrel width and smoothing the mandrel sidewalls. This would reduce the cost of the SIT process. Several key metrics are used to compare the traditional etched mandrel and the slimmed resist mandrel, including: process window, critical dimension uniformity, and defectivity. New resists are shown to have larger process windows after slimming than an etched mandrel process while maintaining comparable critical dimension uniformity. The major challenge to the resist mandrel is the profile post-slim.

  13. Distributed series resistance effects in solar cells

    NASA Astrophysics Data System (ADS)

    Nielsen, L. D.

    1982-05-01

    A mathematical treatment is presented of the effects of one-dimensional distributed series resistance in solar cells. A general perturbation theory is developed, including consistently the induced spatial variation of diode current density and leading to a first-order equivalent lumped resistance of one third the total sheet resistance. For the case of diode characteristics of exponential type and distributed resistance of arbitrary size, unified numerical results are presented for both illuminated and dark characteristics. At high forward dark currents, the distributed series resistance is shown to cause an effective doubling of the 'diode quality factor'.

  14. Resistive Switching Memory Devices Based on Proteins.

    PubMed

    Wang, Hong; Meng, Fanben; Zhu, Bowen; Leow, Wan Ru; Liu, Yaqing; Chen, Xiaodong

    2015-12-01

    Resistive switching memory constitutes a prospective candidate for next-generation data storage devices. Meanwhile, naturally occurring biomaterials are promising building blocks for a new generation of environmentally friendly, biocompatible, and biodegradable electronic devices. Recent progress in using proteins to construct resistive switching memory devices is highlighted. The protein materials selection, device engineering, and mechanism of such protein-based resistive switching memory are discussed in detail. Finally, the critical challenges associated with protein-based resistive switching memory devices are presented, as well as insights into the future development of resistive switching memory based on natural biomaterials. PMID:25753764

  15. Antimicrobial resistance in internal medicine wards.

    PubMed

    Menichetti, Francesco; Tagliaferri, Enrico

    2012-10-01

    Antimicrobial resistance is a global medical problem, affecting most bacterial pathogens. The major challenges are currently posed by methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant enterococci (VRE), Enterobacteriaceae producing extended-spectrum-beta-lactamases (ESBL) and carbapenemases, and multi-resistant strains of Pseudomonas aeruginosa and Acinetobacter baumannii. Therapeutic options are very limited and, in some cases, virtually unavailable. This article provides an overview of the recent epidemiological trends exhibited by the most important multi-resistant pathogens, and of the treatment options that are currently available for these infections. PMID:23073868

  16. Drug Resistance Mechanisms in Mycobacterium tuberculosis

    PubMed Central

    Palomino, Juan Carlos; Martin, Anandi

    2014-01-01

    Tuberculosis (TB) is a serious public health problem worldwide. Its situation is worsened by the presence of multidrug resistant (MDR) strains of Mycobacterium tuberculosis, the causative agent of the disease. In recent years, even more serious forms of drug resistance have been reported. A better knowledge of the mechanisms of drug resistance of M. tuberculosis and the relevant molecular mechanisms involved will improve the available techniques for rapid drug resistance detection and will help to explore new targets for drug activity and development. This review article discusses the mechanisms of action of anti-tuberculosis drugs and the molecular basis of drug resistance in M. tuberculosis. PMID:27025748

  17. Problems in diabetes mellitus management. Insulin resistance.

    PubMed

    Wolfsheimer, K J

    1990-12-01

    Insulin resistance is a cause for morning hyperglycemia seen in diabetic patients. Other reasons for morning hyperglycemia should be eliminated by performing an insulin response test. Once insulin resistance has been established as the cause of hyperglycemia, a step-by-step process should be used to establish the cause of the insulin resistance. Common causes of insulin resistance include hyperadrenocorticism, acromegaly, hyperthyroidism, and obesity. Hepatic disease, renal insufficiency, and sepsis are other causes of insulin resistance in practice. Less common causes include insulin antibodies, pregnancy, neoplasia, hyperandrogenism, and pheochromocytoma. If the underlying cause cannot be found or resolved, then increased doses of insulin are required to manage the hyperglycemia. PMID:2134077

  18. Milbemectin resistance in Tetranychus urticae (Acari: Tetranychidae): selection, stability and cross-resistance to abamectin.

    PubMed

    Nicastro, Roberto Lomba; Sato, Mário Eidi; Da Silva, Marcos Zatti

    2010-03-01

    Studies on artificial laboratory selections with milbemectin, stability of milbemectin resistance and possible cross-resistance with abamectin were carried out with Tetranychus urticae Koch to provide basic information for a milbemectin resistance management program. Selections for resistance and susceptibility to milbemectin were performed in a population of T. urticae, collected from a commercial chrysanthemum field in the State of São Paulo, Brazil. After six selections for resistance and five selections for susceptibility, susceptible (S) and resistant (R) strains of T. urticae to milbemectin were obtained. The resistance ratio (R/S) at the LC(50) reached 409-fold value. The stability of milbemectin resistance was also studied under laboratory conditions, using a population with initial frequency of 75% of resistant mites. The frequencies of milbemectin resistance were evaluated monthly for a period of 7 months. In order to observe possible correlation between milbemectin and abamectin resistance, the frequencies of abamectin resistance were also evaluated for that population, during the same period. The frequency of milbemectin resistance decreased from 75 to 14.5%, while the percentage of abamectin resistant mites decreased from 57 to 9.1%, in 7 months. The frequencies of milbemectin and abamectin resistance were also evaluated in 25 field populations of T. urticae, collected from several crops in the State of São Paulo. The frequencies of milbemectin resistance varied from 4.1 to 89.5%, and of abamectin, from 7.0 to 90.5%. A positive and significant correlation was observed between the frequencies of milbemectin and abamectin resistance, indicating positive cross-resistance between these acaricides. The results indicate that abamectin should be avoided for managing milbemectin resistance in T. urticae. This is the first report on milbemectin resistance in T. urticae in Brazil. PMID:19760100

  19. Resistance to Autolysis in Vancomycin-Selected Staphylococcus aureus Isolates Precedes Vancomycin-Intermediate Resistance

    PubMed Central

    Boyle-Vavra, Susan; Challapalli, Mamatha; Daum, Robert S.

    2003-01-01

    Four clinical U.S. glycopeptide intermediate resistant Staphylococcus aureus (GISA) isolates were resistant to Triton X-100-induced autolysis. Similar resistance was demonstrated in an isolate obtained after a single passage of a susceptible clinical isolate in low-level vancomycin. Strains with the vancomycin-induced Triton X-100 resistance phenotype produced active murein hydrolases but were resistant to lysis by murein hydrolases. PMID:12760894

  20. Molecular bases of plant resistance to arthropods.

    PubMed

    Smith, C Michael; Clement, Stephen L

    2012-01-01

    Arthropod-resistant crops provide significant ecological and economic benefits to global agriculture. Incompatible interactions involving resistant plants and avirulent pest arthropods are mediated by constitutively produced and arthropod-induced plant proteins and defense allelochemicals synthesized by resistance gene products. Cloning and molecular mapping have identified the Mi-1.2 and Vat arthropod resistance genes as CC-NBS-LRR (coiled coil-nucleotide binding site-leucine rich repeat) subfamily NBS-LRR resistance proteins, as well as several resistance gene analogs. Genetic linkage mapping has identified more than 100 plant resistance gene loci and linked molecular markers used in cultivar development. Rice and sorghum arthropod-resistant cultivars and, to a lesser extent, raspberry and wheat cultivars are components of integrated pest management (IPM) programs in Asia, Australia, Europe, and North America. Nevertheless, arthropod resistance in most food and fiber crops has not been integrated due primarily to the application of synthetic insecticides. Plant and arthropod genomics provide many opportunities to more efficiently develop arthropod-resistant plants, but integration of resistant cultivars into IPM programs will succeed only through interdisciplinary collaboration. PMID:21910639

  1. Antibiotic resistance: are we all doomed?

    PubMed

    Collignon, P

    2015-11-01

    Antibiotic resistance is a growing and worrying problem associated with increased deaths and suffering for people. Overall, there are only two factors that drive antimicrobial resistance, and both can be controlled. These factors are the volumes of antimicrobials used and the spread of resistant micro-organisms and/or the genes encoding for resistance. The One Health concept is important if we want to understand better and control antimicrobial resistance. There are many things we can do to better control antimicrobial resistance. We need to prevent infections. We need to have better surveillance with good data on usage patterns and resistance patterns available across all sectors, both human and agriculture, locally and internationally. We need to act on these results when we see either inappropriate usage or resistance levels rising in bacteria that are of concern for people. We need to ensure that food and water sources do not spread multi-resistant micro-organisms or resistance genes. We need better approaches to restrict successfully what and how antibiotics are used in people. We need to restrict the use of 'critically important' antibiotics in food animals and the entry of these drugs into the environment. We need to ensure that 'One Health' concept is not just a buzz word but implemented. We need to look at all sectors and control not only antibiotic use but also the spread and development of antibiotic resistant bacteria - both locally and internationally. PMID:26563691

  2. Generation of Ramoplanin-Resistant Staphylococcus aureus

    PubMed Central

    Schmidt, John W.; Greenough, Adrienne; Burns, Michelle; Luteran, Andrea E.; McCafferty, Dewey G.

    2013-01-01

    Ramoplanin is a lipoglycodepsipeptide antimicrobial active against clinically important Gram-positive bacteria including methicillin resistant Staphylococcus aureus. To proactively examine ramoplanin resistance, we subjected S. aureus NCTC 8325-4 to serial passage in the presence of increasing concentrations of ramoplanin, generating the markedly resistant strain RRSA16. Susceptibility testing of RRSA16 revealed the unanticipated acquisition of cross-resistance to vancomycin and nisin. RRSA16 displayed phenotypes, including a thickened cell wall and reduced susceptibility to Triton X-100 induced autolysis, which are associated with vancomycin intermediate resistant S. aureus strains. Passage of RRSA16 for 18 days in drug-free medium yielded strain R16-18d with restored antibiotic susceptibility. The RRSA16 isolate may be used to identify the genetic and biochemical basis for ramoplanin-resistance and further our understanding of the evolution of antibiotic cross-resistance mechanisms in S. aureus. PMID:20659164

  3. Artemisinin resistance, some facts and opinions.

    PubMed

    Pantaleo, Antonella; Pau, Maria Carmina; Chien, Huynh Dinh; Turrini, Francesco

    2015-06-01

    Resistance to artemisinin derivatives (ARTs) in malaria disease is currently defined as a delayed parasite clearance following artemisinin combined therapy (ACT). Although ACT is still widely effective, the first evidence of artemisinin resistance was described in 2009 in Southeast Asia. Since then, resistance to ARTs / ACT has been monitored showing an increasing trend. The demonstrated resistance to all drugs that are currently associated to ART, the ambiguous finding that ART resistance is observed only in presence of resistance to the partner drug, the lack of a mechanistic rationale to choose the partner drugs and the lack of markers with known specificity and sensitivity to monitor ART resistance, represent the most worrisome issues. PMID:26142668

  4. Resistance to Antibiotics Mediated by Target Alterations

    NASA Astrophysics Data System (ADS)

    Spratt, Brian G.

    1994-04-01

    The development of resistance to antibiotics by reductions in the affinities of their enzymatic targets occurs most rapidly for antibiotics that inactivate a single target and that are not analogs of substrate. In these cases of resistance (for example, resistance to rifampicin), numerous single amino acid substitutions may provide large decreases in the affinity of the target for the antibiotic, leading to clinically significant levels of resistance. Resistance due to target alterations should occur much more slowly for those antibiotics (penicillin, for example) that inactivate multiple targets irreversibly by acting as close analogs of substrate. Resistance to penicillin because of target changes has emerged, by unexpected mechanisms, only in a limited number of species. However, inactivating enzymes commonly provide resistance to antibiotics that, like penicillin, are derived from natural products, although such enzymes have not been found for synthetic antibiotics. Thus, the ideal antibiotic would be produced by rational design, rather than by the modification of a natural product.

  5. Multistate resistive switching in silver nanoparticle films

    NASA Astrophysics Data System (ADS)

    Sandouk, Eric J.; Gimzewski, James K.; Stieg, Adam Z.

    2015-08-01

    Resistive switching devices have garnered significant consideration for their potential use in nanoelectronics and non-volatile memory applications. Here we investigate the nonlinear current-voltage behavior and resistive switching properties of composite nanoparticle films comprising a large collective of metal-insulator-metal junctions. Silver nanoparticles prepared via the polyol process and coated with an insulating polymer layer of tetraethylene glycol were deposited onto silicon oxide substrates. Activation required a forming step achieved through application of a bias voltage. Once activated, the nanoparticle films exhibited controllable resistive switching between multiple discrete low resistance states that depended on operational parameters including the applied bias voltage, temperature and sweep frequency. The films’ resistance switching behavior is shown here to be the result of nanofilament formation due to formative electromigration effects. Because of their tunable and distinct resistance states, scalability and ease of fabrication, nanoparticle films have a potential place in memory technology as resistive random access memory cells.

  6. Generation of ramoplanin-resistant Staphylococcus aureus.

    PubMed

    Schmidt, John W; Greenough, Adrienne; Burns, Michelle; Luteran, Andrea E; McCafferty, Dewey G

    2010-09-01

    Ramoplanin is a lipoglycodepsipeptide antimicrobial active against clinically important Gram-positive bacteria including methicillin-resistant Staphylococcus aureus. To proactively examine ramoplanin resistance, we subjected S. aureus NCTC 8325-4 to serial passage in the presence of increasing concentrations of ramoplanin, generating the markedly resistant strain RRSA16. Susceptibility testing of RRSA16 revealed the unanticipated acquisition of cross-resistance to vancomycin and nisin. RRSA16 displayed phenotypes, including a thickened cell wall and reduced susceptibility to Triton X-100-induced autolysis, which are associated with vancomycin intermediate-resistant S. aureus strains. Passage of RRSA16 for 18 days in a drug-free medium yielded strain R16-18d with restored antibiotic susceptibility. The RRSA16 isolate may be used to identify the genetic and biochemical basis for ramoplanin resistance and to further our understanding of the evolution of antibiotic cross-resistance mechanisms in S. aureus. PMID:20659164

  7. Determining the resistance of carbapenem-resistant Klebsiella pneumoniae to common disinfectants and elucidating the underlying resistance mechanisms

    PubMed Central

    Guo, Wei; Shan, Kai; Xu, Bin; Li, Jianguo

    2015-01-01

    Introduction: Carbapenem-resistant Klebsiella pneumoniae (CRKP) infection is a serious problem in hospitals worldwide, posing a particular risk to immunocompromised patients. Elimination strategies may prevent these drug-resistant bacteria from spreading within hospital environments. Here, the susceptibility of patient-derived CRKP strains to common chemical disinfectants and possible correlations between the presence of drug-resistance genes and increased resistance to disinfectants were investigated. Methods: The minimum inhibitory (MIC) and the minimum bactericidal concentrations (MBC) of common chemical disinfectants against each CRKP strain were determined using agar dilution; K. pneumoniae ATCC700603 served as a standard. The presence of the drug-resistance genes qacΔE, qacA, acrA and qacE was determined using PCR. Results: A total of 27 clinically isolated CRKP strains collected in our hospital from 2011 to 2013 exhibited sensitivity to the following common chemical disinfectants in decreasing order of sensitivity: 75% ethyl alcohol > 2% glutaraldehyde > “84” disinfectant > 0.2% benzalkonium bromide > 2% iodine tincture > 1% iodophor > 0.1% chlorhexidine acetate. Of the 27 strains, 59, 41, 19 and 15% contained qacΔE, qacA, acrA and qacE resistance genes; 15% carried acrA, qacΔE and qacA, and 26% carried both qacA and qacΔE. Comparative analysis indicated that drug-resistance genes were correlated with higher MIC values. Conclusion: These pan-resistant pathogenic CRKP strains contained various drug-resistance genes and exhibited relatively high resistance to ethyl alcohol, chlorhexidine acetate and iodophor. Monitoring the drug-resistance rates of CRKP strains displaying disinfectant resistance may facilitate appropriate and effective sterilisation and thus preventing the spread of these pan-resistant strains PMID:26184804

  8. Thermal Shock-resistant Cement

    SciTech Connect

    Sugama T.; Pyatina, T.; Gill, S.

    2012-02-01

    We studied the effectiveness of sodium silicate-activated Class F fly ash in improving the thermal shock resistance and in extending the onset of hydration of Secar #80 refractory cement. When the dry mix cement, consisting of Secar #80, Class F fly ash, and sodium silicate, came in contact with water, NaOH derived from the dissolution of sodium silicate preferentially reacted with Class F fly ash, rather than the #80, to dissociate silicate anions from Class F fly ash. Then, these dissociated silicate ions delayed significantly the hydration of #80 possessing a rapid setting behavior. We undertook a multiple heating -water cooling quenching-cycle test to evaluate the cement’s resistance to thermal shock. In one cycle, we heated the 200 and #61616;C-autoclaved cement at 500 and #61616;C for 24 hours, and then the heated cement was rapidly immersed in water at 25 and #61616;C. This cycle was repeated five times. The phase composition of the autoclaved #80/Class F fly ash blend cements comprised four crystalline hydration products, boehmite, katoite, hydrogrossular, and hydroxysodalite, responsible for strengthening cement. After a test of 5-cycle heat-water quenching, we observed three crystalline phase-transformations in this autoclaved cement: boehmite and #61614; and #61543;-Al2O3, katoite and #61614; calcite, and hydroxysodalite and #61614; carbonated sodalite. Among those, the hydroxysodalite and #61614; carbonated sodalite transformation not only played a pivotal role in densifying the cementitious structure and in sustaining the original compressive strength developed after autoclaving, but also offered an improved resistance of the #80 cement to thermal shock. In contrast, autoclaved Class G well cement with and without Class F fly ash and quartz flour failed this cycle test, generating multiple cracks in the cement. The major reason for such impairment was the hydration of lime derived from the dehydroxylation of portlandite formed in the autoclaved

  9. Influence resistance on human health

    NASA Astrophysics Data System (ADS)

    Abdul Harits, M.; Bahtiar, Yusuf; Achdan, M. Syahdani; Sunarno, .

    2010-05-01

    Health is an important part of human life. Every person in this world want healthy body, in other words free of any disease. When seeing the pattern of human life today is high activity, always eat instant foods and lack of exercise makes a very bad human health from year to year. Therefore, there is need for the health revolution that can keep human health in order to remain in the condition is always healthy. Eat healthy foods four plus five perfect diligent exercise is the real solution to maintain health. In addition also advisable to always check each month to the doctor so that our health can be controlled. Most people underestimate it, especially the routine checks once a month to the doctor, therefore I created a simple research that aims to get people to mengonytrol health at any time without having to check into the doctor. By utilizing the resistance in the human body's health so we can be controlled. By using a simple tool to measure human resistance by using the concept of the bridge. Bridge circuit used to convert impedance variations into voltage variations. One advantage of this circuit is the voltage produced can vary around 0. This means strengthening can be used to raise the voltage level so as sensitivity to variations in impedance also increases. Another application is the impedance measurement accuracy. The bridge is the simplest and most widely used is the Wheatstone bridge circuit. This circuit is used for signal conditioning applications where a sensor can change the resistance value when the process variable is changed.

  10. Attrition resistant fluidizable reforming catalyst

    DOEpatents

    Parent, Yves O.; Magrini, Kim; Landin, Steven M.; Ritland, Marcus A.

    2011-03-29

    A method of preparing a steam reforming catalyst characterized by improved resistance to attrition loss when used for cracking, reforming, water gas shift and gasification reactions on feedstock in a fluidized bed reactor, comprising: fabricating the ceramic support particle, coating a ceramic support by adding an aqueous solution of a precursor salt of a metal selected from the group consisting of Ni, Pt, Pd, Ru, Rh, Cr, Co, Mn, Mg, K, La and Fe and mixtures thereof to the ceramic support and calcining the coated ceramic in air to convert the metal salts to metal oxides.

  11. Enhanced radiation resistant fiber optics

    DOEpatents

    Lyons, P.B.; Looney, L.D.

    1993-11-30

    A process for producing an optical fiber having enhanced radiation resistance is provided, the process including maintaining an optical fiber within a hydrogen-containing atmosphere for sufficient time to yield a hydrogen-permeated optical fiber having an elevated internal hydrogen concentration, and irradiating the hydrogen-permeated optical fiber at a time while the optical fiber has an elevated internal hydrogen concentration with a source of ionizing radiation. The radiation source is typically a cobalt-60 source and the fiber is pre-irradiated with a dose level up to about 1000 kilorads of radiation. 4 figures.

  12. A corrosive resistant heat exchanger

    DOEpatents

    Richlen, S.L.

    1987-08-10

    A corrosive and erosive resistant heat exchanger which recovers heat from a contaminated heat stream. The heat exchanger utilizes a boundary layer of innocuous gas, which is continuously replenished, to protect the heat exchanger surface from the hot contaminated gas. The innocuous gas is pumped through ducts or perforations in the heat exchanger wall. Heat from the heat stream is transferred by radiation to the heat exchanger wall. Heat is removed from the outer heat exchanger wall by a heat recovery medium. 3 figs., 3 tabs.

  13. Abrasion resistant track shoe grouser

    DOEpatents

    Fischer, Keith D; Diekevers, Mark S; Afdahl, Curt D; Steiner, Kevin L; Barnes, Christopher A

    2013-04-23

    A track shoe for a track-type vehicle. The track shoe includes a base plate and a grouser projecting away from the base plate. A capping surface structure of substantially horseshoe shaped cross-section is disposed across a distal portion of the grouser. The capping surface structure covers portions of a distal edge surface and adjacent lateral surfaces. The capping surface structure is formed from an material characterized by enhanced wear resistance relative to portions of the grouser underlying the capping surface structure.

  14. Resistance minimum and heavy fermions.

    PubMed

    Jun, Kondo

    2006-12-01

    The phenomenon of the resistance minimum in dilute magnetic alloys is explained in terms of the s-d interaction which takes account of scattering of the conduction electron off the magnetic impurities in metals. Some of the intermetallic compounds which involve rare earth elements or uranium show a very large electronic specific heat and remain non-magnetic even though they show a Curie-like susceptibility at higher temperatures. These phenomena are also explained based on the s-d interaction model. PMID:25792794

  15. An improved resistive wall monitor

    SciTech Connect

    Fellenz, Brian; Crisp, Jim

    1998-12-10

    Resistive wall monitors were designed and built for the Fermilab Main Injector project. These devices measure longitudinal beam current from 3 KHz to 4 GHz with a 1 ohm gap impedance. The new design provides a larger aperture and a calibration port to improve the accuracy of single-bunch intensity measurements. Microwave absorber material is used to reduce interference from spurious electromagnetic waves traveling inside the beam pipe. Several types of ferrite materials were evaluated for the absorber. Inexpensive ferrite rods were selected and assembled in an array forming the desired geometry without machining.

  16. Tevatron Resistive Wall Current Monitor

    SciTech Connect

    Crisp, J.; Fellenz, B.; /Fermilab

    2011-01-01

    Resistive Wall Current Monitors (RWCM) were designed and built for the Fermilab Tevatron (Tev) project. These devices measure longitudinal beam current from 3 KHz to 6 GHz with 1.34 ohm gap impedance. There are two RWCM's installed a few feet apart in the Tevatron, upstream RWCM is used for general purpose use, downstream RWCM is dedicated for longitudinal parameters of coalesced beam bunches and bunch intensities. The design provides a calibration or test port for injecting test signals. Microwave absorber material is used to reduce interference from spurious electromagnetic waves traveling inside the beam pipe. This paper will do an overview how the RWCM was designed and its test results.

  17. An improved resistive wall monitor

    SciTech Connect

    Fellenz, B.; Crisp, J.

    1998-12-01

    Resistive wall monitors were designed and built for the Fermilab Main Injector project. These devices measure longitudinal beam current from 3 KHz to 4 GHz with a 1 ohm gap impedance. The new design provides a larger aperture and a calibration port to improve the accuracy of single-bunch intensity measurements. Microwave absorber material is used to reduce interference from spurious electromagnetic waves traveling inside the beam pipe. Several types of ferrite materials were evaluated for the absorber. Inexpensive ferrite rods were selected and assembled in an array forming the desired geometry without machining. {copyright} {ital 1998 American Institute of Physics.}

  18. Corrosion resistant thermal barrier coating

    SciTech Connect

    Levine, S.R.; Miller, R.A.; Hodge, P.E.

    1981-03-01

    A thermal barrier coating system for protecting metal surfaces at high temperature in normally corrosive environments is described. The thermal barrier coating system includes a metal alloy bond coating, the alloy containing nickel, cobalt, iron, or a combination of these metals. The system further includes a corrosion resistant thermal barrier oxide coating containing at least one alkaline earth silicate. The preferred oxides are calcium silicate, barium silicate, magnesium silicate, or combinations of these silicates. Official Gazette of the U.S. Patent and Trademark Office

  19. Resistance minimum and heavy fermions

    PubMed Central

    Jun, Kondo

    2006-01-01

    The phenomenon of the resistance minimum in dilute magnetic alloys is explained in terms of the s-d interaction which takes account of scattering of the conduction electron off the magnetic impurities in metals. Some of the intermetallic compounds which involve rare earth elements or uranium show a very large electronic specific heat and remain non-magnetic even though they show a Curie-like susceptibility at higher temperatures. These phenomena are also explained based on the s-d interaction model. PMID:25792794

  20. CORROSION RESISTANT JACKETED METAL BODY

    DOEpatents

    Brugmann, E.W.

    1958-08-26

    Jacketed metal bodies of the type used as fuel elements for nuclear reactors, which contain an internal elongated body of fissionable material jacketed in a corrosion resistant metal are described. The ends of the internal bodies are provided with screw threads having a tapered outer end. The jacket material overlaps the ends and extends into the tapered section of the screw threaded opening. Screw caps with a mating tapered section are screwed into the ends of the body to compress the jacket material in the tapered sections to provtde an effective seal against corrosive gases and liquids.