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Sample records for attenuate verticillium longisporum

  1. Plant host range of Verticillium longisporum and microsclerotia density in Swedisch soils

    NARCIS (Netherlands)

    Johansson, A.; Goud, J.C.; Dixelius, C.

    2006-01-01

    Verticillium longisporum is a soil-borne fungal pathogen causing vascular wilt of Brassica crops. This study was conducted to enhance our knowledge on the host range of V. longisporum. Seven crop species (barley, oat, oilseed rape, pea, red clover, sugar beet and wheat) and five weed species (barren

  2. Identification and Differentiation of Verticillium Species and V. longisporum Lineages by Simplex and Multiplex PCR Assays

    Science.gov (United States)

    Inderbitzin, Patrik; Davis, R. Michael; Bostock, Richard M.; Subbarao, Krishna V.

    2013-01-01

    Accurate species identification is essential for effective plant disease management, but is challenging in fungi including Verticillium sensu stricto (Ascomycota, Sordariomycetes, Plectosphaerellaceae), a small genus of ten species that includes important plant pathogens. Here we present fifteen PCR assays for the identification of all recognized Verticillium species and the three lineages of the diploid hybrid V. longisporum. The assays were based on DNA sequence data from the ribosomal internal transcribed spacer region, and coding and non-coding regions of actin, elongation factor 1-alpha, glyceraldehyde-3-phosphate dehydrogenase and tryptophan synthase genes. The eleven single target (simplex) PCR assays resulted in amplicons of diagnostic size for V. alfalfae, V. albo-atrum, V. dahliae including V. longisporum lineage A1/D3, V. isaacii, V. klebahnii, V. nonalfalfae, V. nubilum, V. tricorpus, V. zaregamsianum, and Species A1 and Species D1, the two undescribed ancestors of V. longisporum. The four multiple target (multiplex) PCR assays simultaneously differentiated the species or lineages within the following four groups: Verticillium albo-atrum, V. alfalfae and V. nonalfalfae; Verticillium dahliae and V. longisporum lineages A1/D1, A1/D2 and A1/D3; Verticillium dahliae including V. longisporum lineage A1/D3, V. isaacii, V. klebahnii and V. tricorpus; Verticillium isaacii, V. klebahnii and V. tricorpus. Since V. dahliae is a parent of two of the three lineages of the diploid hybrid V. longisporum, no simplex PCR assay is able to differentiate V. dahliae from all V. longisporum lineages. PCR assays were tested with fungal DNA extracts from pure cultures, and were not evaluated for detection and quantification of Verticillium species from plant or soil samples. The DNA sequence alignments are provided and can be used for the design of additional primers. PMID:23823707

  3. Identification and Differentiation of Verticillium Species and V. longisporum Lineages by Simplex and Multiplex PCR Assays.

    Directory of Open Access Journals (Sweden)

    Patrik Inderbitzin

    Full Text Available Accurate species identification is essential for effective plant disease management, but is challenging in fungi including Verticillium sensu stricto (Ascomycota, Sordariomycetes, Plectosphaerellaceae, a small genus of ten species that includes important plant pathogens. Here we present fifteen PCR assays for the identification of all recognized Verticillium species and the three lineages of the diploid hybrid V. longisporum. The assays were based on DNA sequence data from the ribosomal internal transcribed spacer region, and coding and non-coding regions of actin, elongation factor 1-alpha, glyceraldehyde-3-phosphate dehydrogenase and tryptophan synthase genes. The eleven single target (simplex PCR assays resulted in amplicons of diagnostic size for V. alfalfae, V. albo-atrum, V. dahliae including V. longisporum lineage A1/D3, V. isaacii, V. klebahnii, V. nonalfalfae, V. nubilum, V. tricorpus, V. zaregamsianum, and Species A1 and Species D1, the two undescribed ancestors of V. longisporum. The four multiple target (multiplex PCR assays simultaneously differentiated the species or lineages within the following four groups: Verticillium albo-atrum, V. alfalfae and V. nonalfalfae; Verticillium dahliae and V. longisporum lineages A1/D1, A1/D2 and A1/D3; Verticillium dahliae including V. longisporum lineage A1/D3, V. isaacii, V. klebahnii and V. tricorpus; Verticillium isaacii, V. klebahnii and V. tricorpus. Since V. dahliae is a parent of two of the three lineages of the diploid hybrid V. longisporum, no simplex PCR assay is able to differentiate V. dahliae from all V. longisporum lineages. PCR assays were tested with fungal DNA extracts from pure cultures, and were not evaluated for detection and quantification of Verticillium species from plant or soil samples. The DNA sequence alignments are provided and can be used for the design of additional primers.

  4. The ascomycete Verticillium longisporum is a hybrid and a plant pathogen with an expanded host range.

    Directory of Open Access Journals (Sweden)

    Patrik Inderbitzin

    Full Text Available Hybridization plays a central role in plant evolution, but its overall importance in fungi is unknown. New plant pathogens are thought to arise by hybridization between formerly separated fungal species. Evolution of hybrid plant pathogens from non-pathogenic ancestors in the fungal-like protist Phytophthora has been demonstrated, but in fungi, the most important group of plant pathogens, there are few well-characterized examples of hybrids. We focused our attention on the hybrid and plant pathogen Verticillium longisporum, the causal agent of the Verticillium wilt disease in crucifer crops. In order to address questions related to the evolutionary origin of V. longisporum, we used phylogenetic analyses of seven nuclear loci and a dataset of 203 isolates of V. longisporum, V. dahliae and related species. We confirmed that V. longisporum was diploid, and originated three different times, involving four different lineages and three different parental species. All hybrids shared a common parent, species A1, that hybridized respectively with species D1, V. dahliae lineage D2 and V. dahliae lineage D3, to give rise to three different lineages of V. longisporum. Species A1 and species D1 constituted as yet unknown taxa. Verticillium longisporum likely originated recently, as each V. longisporum lineage was genetically homogenous, and comprised species A1 alleles that were identical across lineages.

  5. Aerial Warfare: A Volatile Dialogue between the Plant Pathogen Verticillium longisporum and Its Antagonist Paenibacillus polymyxa.

    Science.gov (United States)

    Rybakova, Daria; Rack-Wetzlinger, Ute; Cernava, Tomislav; Schaefer, Angelika; Schmuck, Maria; Berg, Gabriele

    2017-01-01

    Verticillium wilt caused by Verticillium spp. results in severe yield losses in a broad range of crops. Verticillium outbreaks are challenging to control, and exacerbated by increases in soil temperatures and drought associated with global warming. Employing natural antagonists as biocontrol agents offers a promising approach to addressing this challenge. Paenibacillus polymyxa Sb3-1 was proven to reduce the growth of Verticillium longisporum during in vitro experiments and was shown to promote the growth of oilseed rape seedlings infested with V. longisporum. Our novel approach combined in vitro and in planta methods with the study of the mode of interaction between Sb3-1 and V. longisporum EVL43 via their volatile organic compounds (VOCs). Volatile and soluble substances, produced by both microorganisms as a reaction to one another's VOCs, were detected by using both gas and liquid chromatography-mass spectrometry. P. polymyxa Sb3-1 continually produced antimicrobial and plant growth promoting VOCs, such as 2-nonanone and 3-hydroxy-2-butanone. Several other antimicrobial volatile substances, such as isoamyl acetate and durenol, were downregulated. The general metabolic activity of Sb3-1, including protein and DNA biotransformations, was upregulated upon contact with EVL43 VOCs. V. longisporum increased its production of antimicrobial substances, such as 1-butanol, and downregulated its metabolic activities upon exposure to Sb3-1 VOCs. Additionally, several stress response substances such as arabitol and protein breakdown products (e.g., L-Isoleucyl-L-glutamic acid), were increased in the co-incubated samples. The results obtained depict an ongoing dialog between these microorganisms resulting in growth inhibition, the slowing down of metabolism, and the cell death of V. longisporum due to contact with the P. polymyxa Sb3-1 VOCs. Moreover, the results indicate that VOCs make a substantial contribution to the interaction between pathogens and their natural

  6. Aerial Warfare: A Volatile Dialogue between the Plant Pathogen Verticillium longisporum and Its Antagonist Paenibacillus polymyxa

    Directory of Open Access Journals (Sweden)

    Daria Rybakova

    2017-07-01

    Full Text Available Verticillium wilt caused by Verticillium spp. results in severe yield losses in a broad range of crops. Verticillium outbreaks are challenging to control, and exacerbated by increases in soil temperatures and drought associated with global warming. Employing natural antagonists as biocontrol agents offers a promising approach to addressing this challenge. Paenibacillus polymyxa Sb3-1 was proven to reduce the growth of Verticillium longisporum during in vitro experiments and was shown to promote the growth of oilseed rape seedlings infested with V. longisporum. Our novel approach combined in vitro and in planta methods with the study of the mode of interaction between Sb3-1 and V. longisporum EVL43 via their volatile organic compounds (VOCs. Volatile and soluble substances, produced by both microorganisms as a reaction to one another's VOCs, were detected by using both gas and liquid chromatography-mass spectrometry. P. polymyxa Sb3-1 continually produced antimicrobial and plant growth promoting VOCs, such as 2-nonanone and 3-hydroxy-2-butanone. Several other antimicrobial volatile substances, such as isoamyl acetate and durenol, were downregulated. The general metabolic activity of Sb3-1, including protein and DNA biotransformations, was upregulated upon contact with EVL43 VOCs. V. longisporum increased its production of antimicrobial substances, such as 1-butanol, and downregulated its metabolic activities upon exposure to Sb3-1 VOCs. Additionally, several stress response substances such as arabitol and protein breakdown products (e.g., L-Isoleucyl-L-glutamic acid, were increased in the co-incubated samples. The results obtained depict an ongoing dialog between these microorganisms resulting in growth inhibition, the slowing down of metabolism, and the cell death of V. longisporum due to contact with the P. polymyxa Sb3-1 VOCs. Moreover, the results indicate that VOCs make a substantial contribution to the interaction between pathogens and

  7. Growth of Verticillium longisporum in Xylem Sap of Brassica napus is Independent from Cultivar Resistance but Promoted by Plant Aging.

    Science.gov (United States)

    Lopisso, Daniel Teshome; Knüfer, Jessica; Koopmann, Birger; von Tiedemann, Andreas

    2017-09-01

    As Verticillium stem striping of oilseed rape (OSR), a vascular disease caused by Verticillium longisporum, is extending into new geographic regions and no control with fungicides exists, the demand for understanding mechanisms of quantitative resistance increases. Because V. longisporum is strictly limited to the xylem and resistance is expressed in the systemic stage post root invasion, we investigated a potential antifungal role of soluble constituents and nutritional conditions in xylem sap as determinants of cultivar resistance of OSR to V. longisporum. Assessment of biometric and molecular genetic parameters applied to describe V. longisporum resistance (net area under disease progress curve, stunting, stem thickness, plant biomass, and V. longisporum DNA content) showed consistent susceptibility of cultivar 'Falcon' in contrast to two resistant genotypes, 'SEM' and 'Aviso'. Spectrophotometric analysis revealed a consistently stronger in vitro growth of V. longisporum in xylem sap extracted from OSR compared with the water control. Further comparisons of fungal growth in xylem sap of different cultivars revealed the absence of constitutive or V. longisporum induced antifungal activity in the xylem sap of resistant versus susceptible genotypes. The similar growth of V. longisporum in xylem sap, irrespective of cultivar, infection with V. longisporum and xylem sap filtration, was correlated with about equal amounts of total soluble proteins in xylem sap from these treatments. Interestingly, compared with younger plants, xylem sap from older plants induced significantly stronger fungal growth. Growth enhancement of V. longisporum in xylem sap of aging plants was reflected by increased contents of carbohydrates, which was consistent in mock or V. longisporum-infected plants and independent from cultivar resistance. The improved nutritional conditions in the xylem of more mature plants may explain the late appearance of disease symptoms, which are observed only in

  8. The Vascular Pathogen Verticillium longisporum Does Not Affect Water Relations and Plant Responses to Drought Stress of Its Host, Brassica napus.

    Science.gov (United States)

    Lopisso, Daniel Teshome; Knüfer, Jessica; Koopmann, Birger; von Tiedemann, Andreas

    2017-04-01

    Verticillium longisporum is a host-specific vascular pathogen of oilseed rape (Brassica napus L.) that causes economic crop losses by impairing plant growth and inducing premature senescence. This study investigates whether plant damage through Verticillium stem striping is due to impaired plant water relations, whether V. longisporum affects responses of a susceptible B. napus variety to drought stress, and whether drought stress, in turn, affects plant responses to V. longisporum. Two-factorial experiments on a susceptible cultivar of B. napus infected or noninfected with V. longisporum and exposed to three watering levels (30, 60, and 100% field capacity) revealed that drought stress and V. longisporum impaired plant growth by entirely different mechanisms. Although both stresses similarly affected plant growth parameters (plant height, hypocotyl diameter, and shoot and root dry matter), infection of B. napus with V. longisporum did not affect any drought-related physiological or molecular genetic plant parameters, including transpiration rate, stomatal conductance, photosynthesis rate, water use efficiency, relative leaf water content, leaf proline content, or the expression of drought-responsive genes. Thus, this study provides comprehensive physiological and molecular genetic evidence explaining the lack of wilt symptoms in B. napus infected with V. longisporum. Likewise, drought tolerance of B. napus was unaffected by V. longisporum, as was the level of disease by drought conditions, thus excluding a concerted action of both stresses in the field. Although it is evident that drought and vascular infection with V. longisporum impair plant growth by different mechanisms, it remains to be determined by which other factors V. longisporum causes crop loss.

  9. RabGAP22 is required for defense to the vascular pathogen Verticillium longisporum and contributes to stomata immunity.

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    Jonas Roos

    Full Text Available Verticillium longisporum is a soil-borne pathogen with a preference for plants within the family Brassicaceae. Following invasion of the roots, the fungus proliferates in the plant vascular system leading to stunted plant growth, chlorosis and premature senescence. RabGTPases have been demonstrated to play a crucial role in regulating multiple responses in plants. Here, we report on the identification and characterization of the Rab GTPase-activating protein RabGAP22 gene from Arabidopsis, as an activator of multiple components in the immune responses to V. longisporum. RabGAP22Pro :GUS transgenic lines showed GUS expression predominantly in root meristems, vascular tissues and stomata, whereas the RabGAP22 protein localized in the nucleus. Reduced RabGAP22 transcript levels in mutants of the brassinolide (BL signaling gene BRI1-associated receptor kinase 1, together with a reduction of fungal proliferation following BL pretreatment, suggested RabGAP22 to be involved in BL-mediated responses. Pull-down assays revealed serine:glyoxylate aminotransferase (AGT1 as an interacting partner during V. longisporum infection and bimolecular fluorescence complementation (BiFC showed the RabGAP22-AGT1 protein complex to be localized in the peroxisomes. Further, fungal-induced RabGAP22 expression was found to be associated with elevated endogenous levels of the plant hormones jasmonic acid (JA and abscisic acid (ABA. An inadequate ABA response in rabgap22-1 mutants, coupled with a stomata-localized expression of RabGAP22 and impairment of guard cell closure in response to V. longisporum and Pseudomonas syringae, suggest that RabGAP22 has multiple roles in innate immunity.

  10. Identification and characterization of microRNAs in oilseed rape (Brassica napus) responsive to infection with the pathogenic fungus Verticillium longisporum using Brassica AA (Brassica rapa) and CC (Brassica oleracea) as reference genomes.

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    Shen, Dan; Suhrkamp, Ina; Wang, Yu; Liu, Shenyi; Menkhaus, Jan; Verreet, Joseph-Alexander; Fan, Longjiang; Cai, Daguang

    2014-11-01

    Verticillium longisporum, a soil-borne pathogenic fungus, causes vascular disease in oilseed rape (Brassica napus). We proposed that plant microRNAs (miRNAs) are involved in the plant-V. longisporum interaction. To identify oilseed rape miRNAs, we deep-sequenced two small RNA libraries made from V. longisporum infected/noninfected roots and employed Brassica rapa and Brassica oleracea genomes as references for miRNA prediction and characterization. We identified 893 B. napus miRNAs representing 360 conserved and 533 novel miRNAs, and mapped 429 and 464 miRNAs to the AA and CC genomes, respectively. Microsynteny analysis with the conserved miRNAs and their flanking protein coding sequences revealed 137 AA-CC genome syntenic miRNA pairs and 61 AA and 42 CC genome-unique miRNAs. Sixty-two miRNAs were responsive to the V. longisporum infection. We present data for specific interactions and simultaneously reciprocal changes in the expression levels of the miRNAs and their targets in the infected roots. We demonstrate that miRNAs are involved in the plant-fungus interaction and that miRNA168-Argonaute 1 (AGO1) expression modulation might act as a key regulatory module in a compatible plant-V. longisporum interaction. Our results suggest that V. longisporum may have evolved a virulence mechanism by interference with plant miRNAs to reprogram plant gene expression and achieve infection. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  11. Identification and characterization of microRNAs in oilseed rape (Brassica napus) responsive to infection with the pathogenic fungus Verticillium longisporum using Brassica AA (Brassica rapa) and CC (Brassica oleracea) as reference genomes

    National Research Council Canada - National Science Library

    Shen, Dan; Suhrkamp, Ina; Wang, Yu; Liu, Shenyi; Menkhaus, Jan; Verreet, Joseph‐Alexander; Fan, Longjiang; Cai, Daguang

    2014-01-01

    .... To identify oilseed rape mi RNA s, we deep‐sequenced two small RNA libraries made from V. longisporum infected/noninfected roots and employed Brassica rapa and Brassica oleracea genomes as references for mi RNA prediction and characterization...

  12. Genetic and environmental control of the Verticillium syndrome in Arabidopsis thaliana.

    Science.gov (United States)

    Häffner, Eva; Karlovsky, Petr; Diederichsen, Elke

    2010-11-02

    Verticillium spp. are major pathogens of dicotyledonous plants such as cotton, tomato, olive or oilseed rape. Verticillium symptoms are often ambiguous and influenced by development and environment. The aim of the present study was to define disease and resistance traits of the complex Verticillium longisporum syndrome in Arabidopsis thaliana (L.) Heynh. A genetic approach was used to determine genetic, developmental and environmental factors controlling specific disease and resistance traits and to study their interrelations. A segregating F2/F3 population originating from ecotypes 'Burren' (Bur) and 'Landsberg erecta' (Ler) was established. Plants were root-dip inoculated and tested under greenhouse conditions. The Verticillium syndrome was dissected into components like systemic spread, stunting, development time and axillary branching. Systemic spread of V. longisporum via colonisation of the shoot was extensive in Ler; Bur showed a high degree of resistance against systemic spread. Fungal colonisation of the shoot apex was determined by (a) determining the percentage of plants from which the fungus could be re-isolated and (b) measuring fungal DNA content with quantitative real-time PCR (qPCR). Four quantitative trait loci (QTL) controlling systemic spread were identified for the percentage of plants showing fungal outgrowth, two of these QTL were confirmed with qPCR data. The degree of colonisation by V. longisporum was negatively correlated with development time. QTL controlling development time showed some overlap with QTL for resistance to systemic spread. Stunting depended on host genotype, development time and seasonal effects. Five QTL controlling this trait were identified which did not co-localize with QTL controlling systemic spread. V. longisporum induced increased axillary branching in Bur; two QTL controlling this reaction were found. Systemic spread of V. longisporum in the host as well as resistance to this major disease trait are described for

  13. Genetic and environmental control of the Verticillium syndrome in Arabidopsis thaliana

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    Diederichsen Elke

    2010-11-01

    Full Text Available Abstract Background Verticillium spp. are major pathogens of dicotyledonous plants such as cotton, tomato, olive or oilseed rape. Verticillium symptoms are often ambiguous and influenced by development and environment. The aim of the present study was to define disease and resistance traits of the complex Verticillium longisporum syndrome in Arabidopsis thaliana (L. Heynh. A genetic approach was used to determine genetic, developmental and environmental factors controlling specific disease and resistance traits and to study their interrelations. Results A segregating F2/F3 population originating from ecotypes 'Burren' (Bur and 'Landsberg erecta' (Ler was established. Plants were root-dip inoculated and tested under greenhouse conditions. The Verticillium syndrome was dissected into components like systemic spread, stunting, development time and axillary branching. Systemic spread of V. longisporum via colonisation of the shoot was extensive in Ler; Bur showed a high degree of resistance against systemic spread. Fungal colonisation of the shoot apex was determined by (a determining the percentage of plants from which the fungus could be re-isolated and (b measuring fungal DNA content with quantitative real-time PCR (qPCR. Four quantitative trait loci (QTL controlling systemic spread were identified for the percentage of plants showing fungal outgrowth, two of these QTL were confirmed with qPCR data. The degree of colonisation by V. longisporum was negatively correlated with development time. QTL controlling development time showed some overlap with QTL for resistance to systemic spread. Stunting depended on host genotype, development time and seasonal effects. Five QTL controlling this trait were identified which did not co-localize with QTL controlling systemic spread. V. longisporum induced increased axillary branching in Bur; two QTL controlling this reaction were found. Conclusions Systemic spread of V. longisporum in the host as well as

  14. Bacillus thuringiensis and Bacillus weihenstephanensis Inhibit the Growth of Phytopathogenic Verticillium Species.

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    Hollensteiner, Jacqueline; Wemheuer, Franziska; Harting, Rebekka; Kolarzyk, Anna M; Diaz Valerio, Stefani M; Poehlein, Anja; Brzuszkiewicz, Elzbieta B; Nesemann, Kai; Braus-Stromeyer, Susanna A; Braus, Gerhard H; Daniel, Rolf; Liesegang, Heiko

    2016-01-01

    Verticillium wilt causes severe yield losses in a broad range of economically important crops worldwide. As many soil fumigants have a severe environmental impact, new biocontrol strategies are needed. Members of the genus Bacillus are known as plant growth-promoting bacteria (PGPB) as well as biocontrol agents of pests and diseases. In this study, we isolated 267 Bacillus strains from root-associated soil of field-grown tomato plants. We evaluated the antifungal potential of 20 phenotypically diverse strains according to their antagonistic activity against the two phytopathogenic fungi Verticillium dahliae and Verticillium longisporum. In addition, the 20 strains were sequenced and phylogenetically characterized by multi-locus sequence typing (MLST) resulting in 7 different Bacillus thuringiensis and 13 Bacillus weihenstephanensis strains. All B. thuringiensis isolates inhibited in vitro the tomato pathogen V. dahliae JR2, but had only low efficacy against the tomato-foreign pathogen V. longisporum 43. All B. weihenstephanensis isolates exhibited no fungicidal activity whereas three B. weihenstephanensis isolates showed antagonistic effects on both phytopathogens. These strains had a rhizoid colony morphology, which has not been described for B. weihenstephanensis strains previously. Genome analysis of all isolates revealed putative genes encoding fungicidal substances and resulted in identification of 304 secondary metabolite gene clusters including 101 non-ribosomal polypeptide synthetases and 203 ribosomal-synthesized and post-translationally modified peptides. All genomes encoded genes for the synthesis of the antifungal siderophore bacillibactin. In the genome of one B. thuringiensis strain, a gene cluster for zwittermicin A was detected. Isolates which either exhibited an inhibitory or an interfering effect on the growth of the phytopathogens carried one or two genes encoding putative mycolitic chitinases, which might contribute to antifungal activities

  15. Phylogenetics and taxonomy of the fungal vascular wilt pathogen Verticillium, with the descriptions of five new species.

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    Patrik Inderbitzin

    Full Text Available Knowledge of pathogen biology and genetic diversity is a cornerstone of effective disease management, and accurate identification of the pathogen is a foundation of pathogen biology. Species names provide an ideal framework for storage and retrieval of relevant information, a system that is contingent on a clear understanding of species boundaries and consistent species identification. Verticillium, a genus of ascomycete fungi, contains important plant pathogens whose species boundaries have been ill defined. Using phylogenetic analyses, morphological investigations and comparisons to herbarium material and the literature, we established a taxonomic framework for Verticillium comprising ten species, five of which are new to science. We used a collection of 74 isolates representing much of the diversity of Verticillium, and phylogenetic analyses based on the ribosomal internal transcribed spacer region (ITS, partial sequences of the protein coding genes actin (ACT, elongation factor 1-alpha (EF, glyceraldehyde-3-phosphate dehydrogenase (GPD and tryptophan synthase (TS. Combined analyses of the ACT, EF, GPD and TS datasets recognized two major groups within Verticillium, Clade Flavexudans and Clade Flavnonexudans, reflecting the respective production and absence of yellow hyphal pigments. Clade Flavexudans comprised V. albo-atrum and V. tricorpus as well as the new species V. zaregamsianum, V. isaacii and V. klebahnii, of which the latter two were morphologically indistinguishable from V. tricorpus but may differ in pathogenicity. Clade Flavnonexudans comprised V. nubilum, V. dahliae and V. longisporum, as well as the two new species V. alfalfae and V. nonalfalfae, which resembled the distantly related V. albo-atrum in morphology. Apart from the diploid hybrid V. longisporum, each of the ten species corresponded to a single clade in the phylogenetic tree comprising just one ex-type strain, thereby establishing a direct link to a name tied to a

  16. Dynamics of verticillium species microsclerotia in field soils in response to fumigation, cropping patterns, and flooding.

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    Short, Dylan P G; Sandoya, German; Vallad, Gary E; Koike, Steven T; Xiao, Chang-Lin; Wu, Bo-Ming; Gurung, Suraj; Hayes, Ryan J; Subbarao, Krishna V

    2015-05-01

    Verticillium dahliae is a soilborne, economically significant fungal plant pathogen that persists in the soil for up to 14 years as melanized microsclerotia (ms). Similarly, V. longisporum is a very significant production constraint on members of the family Brassicaceae. Management of Verticillium wilt has relied on methods that reduce ms below crop-specific thresholds at which little or no disease develops. Methyl bromide, a broad-spectrum biocide, has been used as a preplant soil fumigant for over 50 years to reduce V. dahliae ms. However, reductions in the number of ms in the vertical and horizontal soil profiles and the rate at which soil recolonization occurs has not been studied. The dynamics of ms in soil before and after methyl bromide+chloropicrin fumigation were followed over 3 years in six 8-by-8-m sites in two fields. In separate fields, the dynamics of ms in the 60-cm-deep vertical soil profile pre- and postfumigation with methyl bromide+chloropicrin followed by various cropping patterns were studied over 4 years. Finally, ms densities were assessed in six 8-by-8-m sites in a separate field prior to and following a natural 6-week flood. Methyl bromide+chloripicrin significantly reduced but did not eliminate V. dahliae ms in either the vertical or horizontal soil profiles. In field studies, increases in ms were highly dependent upon the crop rotation pattern followed postfumigation. In the vertical soil profile, densities of ms were highest in the top 5 to 20 cm of soil but were consistently detected at 60-cm depths. Six weeks of natural flooding significantly reduced (on average, approximately 65% in the total viable counts of ms) but did not eliminate viable ms of V. longisporum.

  17. SNP association analysis of resistance to Verticillium wilt (Verticillium dahliae Kleb.) in spinach

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    Verticillium wilt, caused by Verticillium dahliae Kleb. is one of important fungus diseases in spinach (Spinacia oleracea L.) and the most economical method of control this disease is through the use of genetic resistance, especially for organic growers. The objective of this research is to evaluate...

  18. Association mapping of resistance to Verticillium wilt in Gossypium ...

    African Journals Online (AJOL)

    Verticillium wilt is a major disease affecting the growth of cotton. For screening the resistant genes, 320 Gossypium hirsutum germplasms were evaluated in Verticillium nursery, and association mapping was used to detect the markers associated with the Verticillium wilt resistance. 106 microsatellite marker primer pairs ...

  19. Verticillium survey results: Is it in red raspberry production fields?

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    Preliminary results of the survey for Verticillium dahliae, the cause of Verticillium wilt, in the Washington Red Raspberry industry were reported at the 2016 Washington Small Fruit Conference. Verticillium was found in many field soils, but was rarely isolated from plants and was just as likely to ...

  20. Biological control agent against verticillium wilt

    CSIR Research Space (South Africa)

    Gumede, WHN

    2006-04-01

    Full Text Available Verticillium wilt Presented at the 14th Biennial congress of the South African Society for Microbiology WHN Gumede CSIR Biosciences 11-04-06 Slide 2 © CSIR 2006 www.csir.co.za INTRODUCTION • Historical background • Application...

  1. Evaluation of Verticillium chlamydosporium and Arthrobotrys ...

    African Journals Online (AJOL)

    The ability of nematode trapping fungi and egg-parasitising fungi to colonize and persist in the rhizosphere of crop plants is thought to be an important factor influencing the success of biological control of root infecting nematodes. In this study, two strains of an egg parasitic fungus Verticillium chlamydosporium (Vc- 10 and ...

  2. Multilocus genotyping based species identification of entomopathogenic fungi of the genus Lecanicillium (=Verticillium lecanii s.l.).

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    Mitina, Galina; Kazartsev, Igor; Vasileva, Aleksandra; Yli-Mattila, Tapani

    2017-11-01

    Mitochondrial gene NADH dehydrogenase subunit 1 (nad1), β-tubulin gene, and elongation factor 1-alpha (tef) were used to characterize and to identify 42 Lecanicillum spp. isolates (former complex species Verticillium lecanii Zimm. Viegas) and to study the phylogenetic relationships in this group. Within the isolates under investigation, Lecanicillium muscarium was the most common species (about 70% of all isolates, collected on the different hosts, predominantly on the insects from the order Hemiptera). Based on nad1 sequencing four main molecular haplotypes were revealed. All four haplotypes have Holarctic origin. Most of them were isolated in the Central part of Russia. One haplotype showed a specific association with the certain geographical area, limited to southwest Georgia and the Krasnodar Territory. For most strains their affiliation to species L. muscarium, L. longisporum, L. psalliotae, L. pissodes were confirmed by the phylogenetic tree, based on the combined sequences of nad1, β-tub, and tef genes. Only five strains of haplotype C and strain F-2643 could not be identified to any present Lecanicillium species and their position remains ambiguous. Thus, the use of multilocus molecular approach based on these genes was useful to identify the Lecanicillium species. Inter-simple sequence repeat (ISSR) study evaluated a high diversity among the L. muscarium strains. The topology of the NJ-tree based on the ISSR-PCR markers has shown the genetic relationships with the support values 62-91% between L. muscarium isolates. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Biological control of Verticillium dahliae by Talaromyces flavus

    NARCIS (Netherlands)

    Nagtzaam, M.P.M.

    1998-01-01

    Verticillium dahliae causes vascular wilt in a wide range of host plants. Control of Verticillium wilt is by soil disinfestation and to a lesser extent by crop rotation or, for a few host plants, by growing resistant varieties. For environmental reasons, the development

  4. Host range of Verticillium isaacii and Verticillium klebahnii from artichoke, spinach, and lettuce

    Science.gov (United States)

    Verticillium is a genus that includes major vascular wilt pathogens. The recent multilocus phylogenetic analyses of the genus identified 5 new species including V. isaacii and V. klebahnii, both of which occur in agricultural soils in coastal California, and have been isolated from asymptomatic and ...

  5. Desirable Traits of a Good Biocontrol Agent against Verticillium Wilt.

    Science.gov (United States)

    Deketelaere, Silke; Tyvaert, Lien; França, Soraya C; Höfte, Monica

    2017-01-01

    The soil-borne fungus Verticillium causes serious vascular disease in a wide variety of annual crops and woody perennials. Verticillium wilt is notoriously difficult to control by conventional methods, so there is great potential for biocontrol to manage this disease. In this study we aimed to review the research about Verticillium biocontrol to get a better understanding of characteristics that are desirable in a biocontrol agent (BCA) against Verticillium wilt. We only considered studies in which the BCAs were tested on plants. Most biocontrol studies were focused on plants of the Solanaceae, Malvaceae , and Brassicaceae and within these families eggplant, cotton, and oilseed rape were the most studied crops. The list of bacterial BCAs with potential against Verticillium was dominated by endophytic Bacillus and Pseudomonas isolates, while non-pathogenic xylem-colonizing Verticillium and Fusarium isolates topped the fungal list. Predominant modes of action involved in biocontrol were inhibition of primary inoculum germination, plant growth promotion, competition and induced resistance. Many BCAs showed in vitro antibiosis and mycoparasitism but these traits were not correlated with activity in vivo and there is no evidence that they play a role in planta . Good BCAs were obtained from soils suppressive to Verticillium wilt, disease suppressive composts, and healthy plants in infested fields. Desirable characteristics in a BCA against Verticillium are the ability to (1) affect the survival or germination of microsclerotia, (2) colonize the xylem and/or cortex and compete with the pathogen for nutrients and/or space, (3) induce resistance responses in the plant and/or (4) promote plant growth. Potential BCAs should be screened in conditions that resemble the field situation to increase the chance of successful use in practice. Furthermore, issues such as large scale production, formulation, preservation conditions, shelf life, and application methods should be

  6. Desirable Traits of a Good Biocontrol Agent against Verticillium Wilt

    Directory of Open Access Journals (Sweden)

    Silke Deketelaere

    2017-07-01

    Full Text Available The soil-borne fungus Verticillium causes serious vascular disease in a wide variety of annual crops and woody perennials. Verticillium wilt is notoriously difficult to control by conventional methods, so there is great potential for biocontrol to manage this disease. In this study we aimed to review the research about Verticillium biocontrol to get a better understanding of characteristics that are desirable in a biocontrol agent (BCA against Verticillium wilt. We only considered studies in which the BCAs were tested on plants. Most biocontrol studies were focused on plants of the Solanaceae, Malvaceae, and Brassicaceae and within these families eggplant, cotton, and oilseed rape were the most studied crops. The list of bacterial BCAs with potential against Verticillium was dominated by endophytic Bacillus and Pseudomonas isolates, while non-pathogenic xylem-colonizing Verticillium and Fusarium isolates topped the fungal list. Predominant modes of action involved in biocontrol were inhibition of primary inoculum germination, plant growth promotion, competition and induced resistance. Many BCAs showed in vitro antibiosis and mycoparasitism but these traits were not correlated with activity in vivo and there is no evidence that they play a role in planta. Good BCAs were obtained from soils suppressive to Verticillium wilt, disease suppressive composts, and healthy plants in infested fields. Desirable characteristics in a BCA against Verticillium are the ability to (1 affect the survival or germination of microsclerotia, (2 colonize the xylem and/or cortex and compete with the pathogen for nutrients and/or space, (3 induce resistance responses in the plant and/or (4 promote plant growth. Potential BCAs should be screened in conditions that resemble the field situation to increase the chance of successful use in practice. Furthermore, issues such as large scale production, formulation, preservation conditions, shelf life, and application methods

  7. Sources of Verticillium dahliae affecting lettuce.

    Science.gov (United States)

    Atallah, Zahi K; Maruthachalam, Karunakaran; Subbarao, Krishna V

    2012-11-01

    ABSTRACT Since 1995, lettuce in coastal California, where more than half of the crop in North America is grown, has consistently suffered from severe outbreaks of Verticillium wilt. The disease is confined to this region, although the pathogen (Verticillium dahliae) and the host are present in other crop production regions in California. Migration of the pathogen with infested spinach seed was previously documented, but the geographic sources of the pathogen, as well as the impact of lettuce seed sparsely infested with V. dahliae produced outside coastal California on the pathogen population in coastal California remain unclear. Population analyses of V. dahliae were completed using 16 microsatellite markers on isolates from lettuce plants in coastal California, infested lettuce seed produced in the neighboring Santa Clara Valley of California, and spinach seed produced in four major spinach seed production regions: Chile, Denmark, the Netherlands, and the United States (Washington State). California produces 80% of spinach in the United States and all seed planted with the majority infested by V. dahliae comes from the above four sources. Three globally distributed genetic populations were identified, indicating sustained migration among these distinct geographic regions with multiple spinach crops produced each year and repeated every year in coastal California. The population structure of V. dahliae from coastal California lettuce plants was heavily influenced by migration from spinach seed imported from Denmark and Washington. Conversely, the sparsely infested lettuce seed had limited or no contribution to the Verticillium wilt epidemic in coastal California. The global trade in plant and seed material is likely contributing to sustained shifts in the population structure of V. dahliae, affecting the equilibrium of native populations, and likely affecting disease epidemiology.

  8. In vitro inhibition of pathogenic Verticillium dahliae , causal agent of ...

    African Journals Online (AJOL)

    In vitro inhibition of pathogenic Verticillium dahliae, causal agent of potato wilt disease in China by Trichoderma isolates. C Xiaojun, S Wongkaew, Y Jie, Y Xuehui, H Haiyong, W Shiping, T Qigqun, W Lishuang, D Athinuwat, N Buensanteai ...

  9. Molecular determinants of resistance to Verticillium dahliae in potato

    Science.gov (United States)

    A constant evolutionary arms race between host resistance genes and pathogen effectors determine adaptive fitness. Therefore, identification of both host resistance genes and pathogen effectors is important in devising effective strategies to control disease. In tomato, resistance to Verticillium da...

  10. Soil suppressiveness towards Meloidogyne Verticillium or Pythium in greenhouse horticulture

    NARCIS (Netherlands)

    Wurff, van der A.W.G.; Slooten, van M.A.; Hamelink, R.; Bohne, S.; Wensveen, van W.

    2011-01-01

    Soils originating from fourteen greenhouse horticultural companies were assessed for the level of suppressiveness of three major pathogens of vegetables and flowers, namely the root knot nematode Meloidogyne incognita, Pythium aphanidermatum and Verticillium dahlia. As controls, three

  11. A Review of Control Options and Externalities for Verticillium Wilts.

    Science.gov (United States)

    Carroll, Christine L; Carter, Colin A; Goodhue, Rachael E; Lawell, C-Y Cynthia Lin; Subbarao, Krishna V

    2018-02-01

    Plant pathogens migrate to new regions through human activities such as trade, where they may establish themselves and cause disease on agriculturally important crops. Verticillium wilt of lettuce, caused by Verticillium dahliae, is a soilborne fungus that was introduced to coastal California via infested spinach seeds. It has caused significant losses for lettuce growers. Once introduced, Verticillium wilt could be managed by fumigating with methyl bromide and chloropicrin, but this option is no longer available. Growers can also manage the disease by planting broccoli or not planting spinach. These control options require long-term investments for future gain. Verticillium wilt can also be prevented or controlled by testing and providing spinach seeds with little or no V. dahliae infestation. However, seed companies have been reluctant to test or clean spinach seeds, as spinach crops are not affected by Verticillium wilt. Thus, available control options are affected by externalities. Renters and other producers with short time horizons will not undertake long-term investments and seed companies do not take into account the effect of their decision not to test on lettuce producers. We review the literature on the economics of managing crop disease; discuss the economics of managing Verticillium wilt; and review the recent research on the externalities that arise with short-term growers, and between seed companies and growers due to Verticillium wilt. An externality arises whenever the actions of one individual or firm affects the payoffs to another individual or firm not involved in a specific transaction. These externalities have important implications for the management of Verticillium wilt and, more broadly, for the management of migratory pathogens and the diseases they cause in agriculture in general. This review is of interest to policy-makers, the producers, marketers, seed companies, and researchers.

  12. Biological control of Verticillium dahliae by Talaromyces flavus

    OpenAIRE

    Nagtzaam, M.P.M.

    1998-01-01

    Verticillium dahliae causes vascular wilt in a wide range of host plants. Control of Verticillium wilt is by soil disinfestation and to a lesser extent by crop rotation or, for a few host plants, by growing resistant varieties. For environmental reasons, the development of alternatives to chemical soil disinfestation is being sought. Biocontrol by microbial agents is one of the options. The potential of Talaromyces flavus as a biocontrol agen...

  13. Reliable detection of unevenly distributed Verticillium dahliae in diseased olive trees

    NARCIS (Netherlands)

    Keykha Saber, Mojtaba; Pham, K.T.K.; Thomma, B.P.H.J.; Hiemstra, J.A.

    2017-01-01

    Verticillium wilt caused by Verticillium dahliae is one of the most threatening diseases of olive worldwide. For pre-planting and post-planting control of verticillium wilt in olive trees, availability of a rapid, reliable and non-destructive method for detection of V. dahliae is essential. For such

  14. Molecular research and genetic engineering of resistance to Verticillium wilt in cotton: A review

    Science.gov (United States)

    Verticillium dahliae, a soil-borne pathogen, causes Verticillium wilt, one of the most serious diseases in cotton, deleteriously influencing the crop’s production and quality. Verticillium wilt has become a major obstacle in cotton production since Helicoverpa armigera, the cotton bollworm, became e...

  15. Comparative RNA-seq for the investigation of tolerance to Verticillium wilt in black raspberry

    Science.gov (United States)

    Verticillium dahliae Kleb., a cause of verticillium wilt, is a wide-spread, soil-borne fungal pathogen with a wide host range that includes many fruit and vegetable crops. Verticillium dahliae has been isolated from Rubus species showing symptoms of the disease. Very little is known about the intera...

  16. Verticillium wilt in nursery trees: damage thresholds, spatial and temporal aspects

    NARCIS (Netherlands)

    Goud, J.C.; Termorshuizen, A.J.; Bruggen, van A.H.C.

    2011-01-01

    Verticillium wilt can cause high losses in tree nurseries. To be able to predict disease and unravel disease dynamics over time and space, the relationship between verticillium wilt and soil inoculum densities of Verticillium dahliae and the nematode Pratylenchus fallax was studied in two 4-year

  17. Repetitive elements, architects of genomic variation in Verticillium

    Science.gov (United States)

    Vascular wilt pathogens in the genus Verticillium show considerable variation with respect to their host ranges, genomic organization, and the variety and number of transposable elements (TEs) that they carry. These families of TE sequences were first documented in the wide host range, plant pathog...

  18. Effect of solarization with fresh chicken manure on verticillium wilt ...

    African Journals Online (AJOL)

    The present study was carried out to evaluate the effect of reducing wilt disease through the medium of fresh chicken manure (FCM) mixed with soil before solarized and then artificial Verticillium dahliae (V.d) inoculation on yield of eggplant (Solanum melongena L.) under field conditions. According to the splitplot design, ...

  19. Biological control of Rhizoctonia solani on potato by Verticillium ...

    African Journals Online (AJOL)

    STORAGESEVER

    2009-06-03

    Jun 3, 2009 ... sclerotia of R. solani was reduced by V. biguttatum isolates. V. biguttatum also significantly reduced the disease severity of R. solani on potato sprouts in pot experiments. This is the first report of V. biguttatum from sclerotia of R. solani in Turkey. Key words: Bio-control, potato, Rhizoctonia solani, Verticillium ...

  20. Insertional mutagenesis in the vascular wilt pathogen Verticillium dahliae

    NARCIS (Netherlands)

    Santhanam, P.

    2014-01-01

    Vascular wilt diseases caused by soil-borne pathogens are among the most devastating plant diseases worldwide. The ascomycete fungus Verticillium dahliae causes vascular wilt diseases in hundreds of dicotyledonous plant species, including important crops such as eggplant, lettuce, olive, spinach

  1. Biological control of Rhizoctonia solani on potato by Verticillium ...

    African Journals Online (AJOL)

    Ten isolates of Verticillium biguttatum were obtained from sclerotia of Rhizoctonia solani on potato tubers in Erzurum, Turkey. The interaction between V. biguttatum and R. solani was studied in vitro and in vivo. V. biguttatum isolates affected R. solani by antibiosis and parasitism. All isolates of V. biguttatum inhibited the ...

  2. Selection for resistance to Verticillium wilt caused by race 2 isolates of Verticillium dahliae in accessions of lettuce (Lactuca sativa L.).

    Science.gov (United States)

    Verticillium wilt of lettuce caused by Verticillium dahliae can cause severe economic damage to lettuce producers. The pathogen exists as two races (races 1 and 2) in lettuce, and complete resistance to race 1 is known. Resistance to race 2 isolates has not been reported, and production of race 1 re...

  3. Iceberg lettuce breeding lines with resistance to Verticillium wilt caused by race 1 isolates of Verticillium dahliae.

    Science.gov (United States)

    The Agricultural Research Service, United States Department of Agriculture and the University of California, Davis, announce the release of two breeding lines of lettuce (Lactuca sativa L.). Lines RH08-0472 and RH08-0475 are F9 iceberg type lettuce breeding lines with resistance to Verticillium wil...

  4. Verticillium dahliae disease resistance and the regulatory pathway for maturity and tuberization in potato

    DEFF Research Database (Denmark)

    Tai, Helen H.; De Koyer, David; Sønderkær, Mads

    2017-01-01

    Verticillium dahliae Kleb. is a pathogenic fungus causing wilting, chlorosis and early dying in potato. Genetic mapping of resistance to V. dahliae was done using a diploid population of potato. The major quantitative trait locus (QTL) for Verticillium resistance was found on chromosome 5. The St...

  5. Breeding and genetics of lettuce for resistance against race 2 Verticillium wilt

    Science.gov (United States)

    Verticillium wilt, caused by Verticillium dahliae Kleb., is an economically important disease of lettuce in central coastal California. Most isolates of the pathogen detected in the Salinas Valley belong to race 1 for which complete resistance exists. However, adequate level of resistance is not ava...

  6. The economics of managing Verticillium wilt, an imported disease in California lettuce

    Directory of Open Access Journals (Sweden)

    Christine L. Carroll

    2017-09-01

    Full Text Available Verticillium dahliae is a soilborne fungus that is introduced to the soil via infested spinach seeds and that causes lettuce to be afflicted with Verticillium wilt. This disease has spread rapidly through the Salinas Valley, the prime lettuce production region of California. Verticillium wilt can be prevented or controlled by the grower by fumigating, planting broccoli, or not planting spinach. Because these control options require long-term investment for future gain, renters might not take the steps needed to control Verticillium wilt. Verticillium wilt can also be prevented or controlled by a spinach seed company through testing and cleaning the spinach seeds. However, seed companies are unwilling to test or clean spinach seeds, as they are not affected by this disease. We discuss our research on the externalities that arise with renters, and between seed companies and growers, due to Verticillium wilt. These externalities have important implications for the management of Verticillium wilt in particular, and for the management of diseases in agriculture in general.

  7. A model for multiseasonal spread of verticillium wilt of lettuce.

    Science.gov (United States)

    Wu, B M; Subbarao, K V

    2014-09-01

    Verticillium wilt, caused by Verticillium dahliae, is a destructive disease in lettuce, and the pathogen is seedborne. Even though maximum seed infestation rates of lettuce seed lots, it is necessary to establish acceptable contamination thresholds to prevent introduction and establishment of the pathogen in lettuce production fields. However, introduction of inoculum into lettuce fields for experimental purposes to determine its long term effects is undesirable. Therefore, we constructed a simulation model to study the spread of Verticillium wilt following pathogen introduction from seed. The model consists of four components: the first for simulating infection of host plants, the second for simulating reproduction of microsclerotia on diseased plants, the third for simulating the survival of microsclerotia, and the fourth for simulating the dispersal of microsclerotia. The simulation results demonstrated that the inoculum density-disease incidence curve parameters and the dispersal gradients affect disease spread in the field. Although a steep dispersal gradient facilitated the establishment of the disease in a new field with a low inoculum density, a long-tail gradient allowed microsclerotia to be dispersed over greater distances, promoting the disease spread in fields with high inoculum density. The simulation results also revealed the importance of avoiding successive lettuce crops in the same field, reducing survival rate of microsclerotia between crops, and the need for breeding resistance against V. dahliae in lettuce cultivars to lower the number of microsclerotia formed on each diseased plant. The simulation results, however, suggested that, even with a low seed infestation rate, the pathogen would eventually become established if susceptible lettuce cultivars were grown consecutively in the same field for many years. A threshold for seed infestation can be established only when two of the three drivers of the disease-(i) low microsclerotia production per

  8. Nachweis von Verticillium dahliae an Pfefferminze (Mentha x piperita L.

    Directory of Open Access Journals (Sweden)

    Gärber, Ute

    2014-09-01

    Full Text Available In Beständen von Pfefferminze wurden Krankheitssymptome beobachtet, die sich in Wuchshemmungen, Stängelverbräunungen, Blattchlorosen und Welke zeigten. Teilweise starben die Pflanzen bzw. einzelne Triebe ab. Als Ursache konnte Verticillium dahliae nachgewiesen werden. In einem Infektionsversuch im Gewächshaus wurden sieben Wochen alte Pfefferminzpflanzen der Sorte Multimentha durch Angießen mit einer Konidiensuspension (106 Konidien/ml Suspension inokuliert. Erste Krankheitssymptome erschienen acht Wochen nach Inokulation. Innerhalb kurzer Zeit nahm der Befall stark zu. Aus den kranken Pflanzenteilen wie Stängel und Blatt konnte der Erreger reisoliert werden.

  9. Bestrijding van Verticillium in de bodem : in de teelt van laanbomen (klei) en rozen (zand)

    NARCIS (Netherlands)

    Hiemstra, J.A.; Sluis, van der B.J.

    2014-01-01

    1 Samenvatting en conclusies De in dit rapport beschreven experimenten werden opgezet om een aantal nieuwe methoden (alternatieven voor chemische bodemontsmetting) te testen op hun werkzaamheid voor wat betreft bestrijding van Verticillium dahliae (Vd) en daarnaast ook nematoden (Pratylenchus

  10. Potential of Endophytic Fungi Isolated from Cotton Roots for Biological Control against Verticillium Wilt Disease

    OpenAIRE

    Yuan, Yuan; Feng, Hongjie; Wang, Lingfei; Li, Zhifang; Shi, Yongqiang; Zhao, LiHong; Feng, Zili; Zhu, Heqin

    2017-01-01

    Verticillium wilt is a soil-borne disease, and severely limits the development of cotton production. To investigate the role of endophytic fungi on Verticillium wilt, CEF-818 (Penicillium simplicissimum), CEF-714 (Leptosphaeria sp.), CEF-642 (Talaromyces flavus.) and CEF-193 (Acremonium sp.) isolated from cotton roots were used to assess their effects against cotton wilt disease caused by a defoliating V. dahliae strain Vd080. In the greenhouse, all treatments significantly reduced disease in...

  11. Companion cropping with potato onion enhances the disease resistance of tomato against Verticillium dahliae

    OpenAIRE

    Fu, Xuepeng; Wu, Xia; Zhou, Xingang; Liu, Shouwei; Shen, Yanhui; Wu, Fengzhi

    2015-01-01

    Intercropping could alleviate soil-borne diseases, however, few studies focused on the immunity of the host plant induced by the interspecific interactions. To test whether or not intercropping could enhance the disease resistance of host plant, we investigated the effect of companion cropping with potato onion on tomato Verticillium wilt caused by Verticillium dahliae (V. dahliae). To investigate the mechanisms, the root exudates were collected from tomato and potato onion which were grown t...

  12. ANTAGONISMO IN VITRO DE Trichoderma spp. A Verticillium dahliae KLEB

    Directory of Open Access Journals (Sweden)

    M.P. MARTINS-CORDER

    1998-01-01

    Full Text Available O presente trabalho visou testar e selecionar isolados selvagens de Trichoderma spp. quanto à capacidade antagônica ao fungo fitopatogênico Verticillium dahliae. Os ensaios in vitro consistiram de testes para avaliar a capacidade hiperparasítica e de antibiose através da produção de metabólitos voláteis e não voláteis. Pela técnica de culturas pareadas, 47 isolados de diversas espécies de Trichoderma foram avaliados e, pelos resultados obtidos, 20 foram selecionados. Através do teste de antibiose, selecionaram-se 7 isolados: T15P e Tal-1 (T. viride, TW6 e CNP311A (T. koningii, CNP17 e TCII (T. harzianum e Tal-10 (T. aureoviride os quais inibiram completamente o crescimento micelial de V. dahliae através da produção de metabólitos. Observações microscópicas demonstraram interações de hifas entre Trichoderma sp. e V. dahliae, tais como: enrolamento, crescimento paralelo de ambos, formação de ganchos.This work was carried out to test and to select wild strains of Trichoderma spp. with antagonistic ability against Verticillium dahliae. The in vitro assay consisted of the antibiosis technique by assessment of volatile and non-volatile metabilites and hyphal interaction. Forty seven Trichoderma strains were evaluated and twenty strains were selected by their antagonistic ability against V. dahliae. Through the antibiosis test, seven strains of different species T15P and Tal-1 (T. viride; TW6 and CNP311A (T. koningii; CNP17 and TCII (T. harzianum and Tal-10 (T. aureoviride inhibited the mycelial growth of V. dahliae due to the production of metabolites. Several kinds of hyphal interference were observed such as coiling and hook formation.

  13. Colonization of spinach by Verticillium dahliae and effects of pathogen localization on the efficacy of seed treatments

    Science.gov (United States)

    Verticillium wilt is caused by the soilborne fungus V. dahliae on spinach (Spinacia oleracea L.) but the disease is a serious problem only in seed production fields. Spinach crops are harvested well before symptom expression, and thus, Verticillium wilt is not a significant threat in fresh and proc...

  14. Transposable elements in phytopathogenic Verticillium spp.: insights into genome evolution and inter- and intra-specific diversification

    Science.gov (United States)

    Verticillium dahliae (Vd) and Verticillium albo-atrum (Va) are cosmopolitan soil fungi causing very disruptive vascular diseases on a wide range of crop plants. To date, no sexual stage has been identified in either microorganism suggesting that somatic mutation is a major force in generating geneti...

  15. Segregation of unknown signaling components in potato complicates marker-assisted selection for Ve-mediated Verticillium resistance

    Science.gov (United States)

    Verticillium wilt (VW), caused primarily by soil-borne fungi Verticillium dahliae Kleb and V. albo-atrum Reinke and Berthold is characterized by unilateral wilting of leaves, chlorosis, and premature senescence. VW is mainly controlled by fumigating fields with metam sodium, which has negative econo...

  16. Cotton GhBAK1 mediates Verticillium wilt resistance and cell death.

    Science.gov (United States)

    Gao, Xiquan; Li, Fangjun; Li, Maoying; Kianinejad, Ali S; Dever, Jane K; Wheeler, Terry A; Li, Zhaohu; He, Ping; Shan, Libo

    2013-07-01

    Virus-induced gene silencing (VIGS) offers a powerful approach for functional analysis of individual genes by knocking down their expression. We have adopted this approach to dissect gene functions in cotton resistant to Verticillium wilt, one of the most devastating diseases worldwide. We showed here that highly efficient VIGS was obtained in a cotton breeding line (CA4002) with partial resistance to Verticillium wilt, and GhMKK2 and GhVe1 are required for its resistance to Verticillium wilt. Arabidopsis AtBAK1/SERK3, a central regulator in plant disease resistance, belongs to a subfamily of somatic embryogenesis receptor kinases (SERKs) with five members, AtSERK1 to AtSERK5. Two BAK1 orthologs and one SERK1 ortholog were identified in the cotton genome. Importantly, GhBAK1 is required for CA4002 resistance to Verticillium wilt. Surprisingly, silencing of GhBAK1 is sufficient to trigger cell death accompanied with production of reactive oxygen species in cotton. This result is distinct from Arabidopsis in which AtBAK1 and AtSERK4 play redundant functions in cell death control. Apparently, cotton has only evolved SERK1 and BAK1 whereas AtSERK4/5 are newly evolved genes in Arabidopsis. Our studies indicate the functional importance of BAK1 in Verticillium wilt resistance and suggest the dynamic evolution of SERK family members in different plant species. © 2013 Institute of Botany, Chinese Academy of Sciences.

  17. Proteomic identification of differentially expressed proteins in Gossypium thurberi inoculated with cotton Verticillium dahliae.

    Science.gov (United States)

    Zhao, Fu'an; Fang, Weiping; Xie, Deyi; Zhao, Yuanming; Tang, Zhongjie; Li, Wu; Nie, Lihong; Lv, Shuping

    2012-04-01

    Thurber's cotton (Gossypium thurberi) is the wild relative of cultivated cotton. It is highly resistant to cotton Verticillium wilt, a disease that significantly affects cotton yield and quality. To reveal the mechanism of disease resistance in G. thurberi and to clone resistance-related genes, we used two-dimensional electrophoresis (2-DE) and tandem time-of-flight mass spectrometry (MALDI-TOF-MS) to identify differentially expressed proteins in Thurber's cotton after inoculation with Verticillium dahliae. A total of 57 different protein spots were upregulated, including 52 known proteins representing 11% of the total protein spots. These proteins are involved in resistance to stress and disease, transcriptional regulation, signal transduction, protein processing and degradation, photosynthesis, production capacity, basic metabolism, and other processes. In addition, five disease resistance proteins showed intense upregulation, indicating that resistance genes (R genes) may play a critical role in resistance to Verticillium wilt in Thurber's cotton. Our results suggest that disease and stress resistance are the combined effects of multiple co-expressed genes. This provides a basis for further, detailed investigation into the mechanisms underlying Verticillium wilt resistance of G. thurberi and for cloning essential genes into cotton cultivars to produce Verticillium wilt resistant plants. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  18. Temporal patterns of cotton Fusarium and Verticillium wilt in Jiangsu coastal areas of China.

    Science.gov (United States)

    Li, Xiaogang; Zhang, Ya'nan; Ding, Changfeng; Xu, Wenhua; Wang, Xingxiang

    2017-10-03

    Cotton diseases caused by soil-borne pathogenic fungi present a major constraint to cotton production not only in China but also worldwide. A long-term field inventory was made of the prevalence of Fusarium and Verticillium wilt of cotton in the Jiangsu coastal area of China from 2000 to 2014. Various factors (crop varieties, rotation and weather) were analyzed to explore the dynamics of these diseases in cotton. The results showed that the prevalence of Fusarium and Verticillium wilt increased before 2005 and that Verticillium wilt remained at a high incidence over most of the past 10 years, while Fusarium wilt began to gradually decrease after 2005. The dynamics of Fusarium and Verticillium wilt were closely associated with the introduced cotton varieties and the intensive cropping history. In addition, weather conditions occurring during some of the years appeared to coincide with a substantial variation in the wilt diseases. Our study highlighted epidemiological dynamics of Fusarium and Verticillium wilt in a long-term survey.

  19. Entomopathogenic Potential of Verticillium and Acremonium Species (Deuteromycotina: Hyphomycetes)

    DEFF Research Database (Denmark)

    Steenberg, Tove; Humber, Richard A

    1999-01-01

    Hyphomycetes with conidia formed in slimy heads from hyaline mycelium were isolated from a range of insect hosts. Isolation on artificial medium and microscopic examination revealed that these fungi in many cases mere not Verticillium lecanii despite a superficial resemblance to this common...... entomopathogen. The fungi were identified as Verticillium fusisporum, Veritcillium psalliotae, Verticillium lamellicola, and species of Acremonium. Isolates of these fungi were bioassayed against the sweet-potato whitefly (Bemisia tabaci) and against the housefly (Musca domestica) to examine...... their entomopathogenicity. A test was also conducted with a coleopteran (lesser mealworm, Alphitobius diaperinus) to further evaluate the host range for some of the fungi. V. lamellicola was not pathogenic to the two species of insects treated, while varying levels of pathogenicity were shown for the other species...

  20. Preventing an increase in Verticillium wilt incidence in spinach seed production

    DEFF Research Database (Denmark)

    Olesen, Merete Halkjær; Deleuran, Lise Christina; Gislum, René

    2014-01-01

    A semifield assay was conducted from 2009 to 2011 to distinguish between different preventive methods of reducing Verticillium spp. in spinach seed production. The seed treatments for controlling seed infection levels included Thiram, Signum, Trichoderma harzianum, Gliocladium roseum and Natural II......, and these were tested in naturally infested and uninfested soil. Even though seed treatment by Thiram and Signum in all cases reduced the incidence of Verticillium spp. on the harvested seed, the soil type had a large influence on the subsequent disease pressure as a significant effect of soil was seen in 2010...

  1. Identification of molecular markers associated with Verticillium wilt resistance in alfalfa (Medicago sativa L. using high-resolution melting.

    Directory of Open Access Journals (Sweden)

    Tiejun Zhang

    Full Text Available Verticillium wilt, caused by the soilborne fungus, Verticillium alfalfae, is one of the most serious diseases of alfalfa (Medicago sativa L. worldwide. To identify loci associated with resistance to Verticillium wilt, a bulk segregant analysis was conducted in susceptible or resistant pools constructed from 13 synthetic alfalfa populations, followed by association mapping in two F1 populations consisted of 352 individuals. Simple sequence repeat (SSR and single nucleotide polymorphism (SNP markers were used for genotyping. Phenotyping was done by manual inoculation of the pathogen to replicated cloned plants of each individual and disease severity was scored using a standard scale. Marker-trait association was analyzed by TASSEL. Seventeen SNP markers significantly associated with Verticillium wilt resistance were identified and they were located on chromosomes 1, 2, 4, 7 and 8. SNP markers identified on chromosomes 2, 4 and 7 co-locate with regions of Verticillium wilt resistance loci reported in M. truncatula. Additional markers identified on chromosomes 1 and 8 located the regions where no Verticillium resistance locus has been reported. This study highlights the value of SNP genotyping by high resolution melting to identify the disease resistance loci in tetraploid alfalfa. With further validation, the markers identified in this study could be used for improving resistance to Verticillium wilt in alfalfa breeding programs.

  2. Identification of molecular markers associated with Verticillium wilt resistance in alfalfa (Medicago sativa L.) using high-resolution melting.

    Science.gov (United States)

    Zhang, Tiejun; Yu, Long-Xi; McCord, Per; Miller, David; Bhamidimarri, Suresh; Johnson, David; Monteros, Maria J; Ho, Julie; Reisen, Peter; Samac, Deborah A

    2014-01-01

    Verticillium wilt, caused by the soilborne fungus, Verticillium alfalfae, is one of the most serious diseases of alfalfa (Medicago sativa L.) worldwide. To identify loci associated with resistance to Verticillium wilt, a bulk segregant analysis was conducted in susceptible or resistant pools constructed from 13 synthetic alfalfa populations, followed by association mapping in two F1 populations consisted of 352 individuals. Simple sequence repeat (SSR) and single nucleotide polymorphism (SNP) markers were used for genotyping. Phenotyping was done by manual inoculation of the pathogen to replicated cloned plants of each individual and disease severity was scored using a standard scale. Marker-trait association was analyzed by TASSEL. Seventeen SNP markers significantly associated with Verticillium wilt resistance were identified and they were located on chromosomes 1, 2, 4, 7 and 8. SNP markers identified on chromosomes 2, 4 and 7 co-locate with regions of Verticillium wilt resistance loci reported in M. truncatula. Additional markers identified on chromosomes 1 and 8 located the regions where no Verticillium resistance locus has been reported. This study highlights the value of SNP genotyping by high resolution melting to identify the disease resistance loci in tetraploid alfalfa. With further validation, the markers identified in this study could be used for improving resistance to Verticillium wilt in alfalfa breeding programs.

  3. AAC as a Potential Target Gene to Control Verticillium dahliae

    Directory of Open Access Journals (Sweden)

    Xiaofeng Su

    2017-01-01

    Full Text Available Verticillium dahliae invades the roots of host plants and causes vascular wilt, which seriously diminishes the yield of cotton and other important crops. The protein AAC (ADP, ATP carrier is responsible for transferring ATP from the mitochondria into the cytoplasm. When V. dahliae protoplasts were transformed with short interfering RNAs (siRNAs targeting the VdAAC gene, fungal growth and sporulation were significantly inhibited. To further confirm a role for VdAAC in fungal development, we generated knockout mutants (ΔVdACC. Compared with wild-type V. dahliae (Vd wt, ΔVdAAC was impaired in germination and virulence; these impairments were rescued in the complementary strains (ΔVdAAC-C. Moreover, when an RNAi construct of VdAAC under the control of the 35S promoter was used to transform Nicotiana benthamiana, the expression of VdAAC was downregulated in the transgenic seedlings, and they had elevated resistance against V. dahliae. The results of this study suggest that VdAAC contributes to fungal development, virulence and is a promising candidate gene to control V. dahliae. In addition, RNAi is a highly efficient way to silence fungal genes and provides a novel strategy to improve disease resistance in plants.

  4. Colonization of spinach (Spinacia oleracea L.) by GFP-tagged verticillium dahliae.

    Science.gov (United States)

    The soilborne fungus, Verticillium dahliae, causes wilt in a wide range of hosts, including spinach (Spinacia oleracea L.). The interaction between a green fluorescent protein (GFP)-tagged V. dahliae strain and spinach was studied by confocal laser scanning microscopy. The roots of spinach seedlings...

  5. Distribution and persistence of Verticillium dahliae in the xylem of Norway maple and European ash trees

    NARCIS (Netherlands)

    Keykha Saber, Mojtaba; Thomma, Bart P.H.J.; Hiemstra, Jelle A.

    2018-01-01

    Verticillium dahliae colonizes the xylem vessels of susceptible host plants. Hence it can be expected that the distribution of the fungus as well as disease progress will be influenced by the anatomy of the xylem of that host. Here, we studied the spatial and temporal distribution of V. dahliae in

  6. Analysis of a MULE-cyanide hydratase gene fusion in Verticillium dahliae

    Science.gov (United States)

    The genome of the phytopathogenic fungus Verticillium dahliae encodes numerous Class II “cut-and-paste” transposable elements, including those of a small group of MULE transposons. We have previously identified a fusion event between a MULE transposon sequence and sequence encoding a cyanide hydrata...

  7. Optimization of Verticillium lecanii spore production in solid-state fermentation on sugarcane bagasse

    NARCIS (Netherlands)

    Shi, Y.; Xu, X.; Zhu, Y.

    2009-01-01

    Verticillium lecanii is an entomopathogen with high potential in biological control of pests. We developed a solid-state fermentation with sugarcane bagasse as carrier absorbing liquid medium to propagate V. lecanii spores. Using statistical experimental design, we optimized the medium composition

  8. Quantification of microsclerotia of Verticillium dahliae in plant material by image analysis

    NARCIS (Netherlands)

    Mol, L.; Meijer, E.M.J.

    1995-01-01

    A procedure for the quantification of microsclerotia ofVerticillium dahliae with an image analysis system was compared with counting by eye. Colonised potato plant material was used from plants grown in pathogen-free soil in a greenhouse and from twelve crops (including four potato cultivars) grown

  9. The inheritance of resistance to Verticillium wilt caused by race 1 isolates of Verticillium dahliae in the lettuce cultivar La Brillante.

    Science.gov (United States)

    Hayes, Ryan J; McHale, Leah K; Vallad, Gary E; Truco, Maria Jose; Michelmore, Richard W; Klosterman, Steve J; Maruthachalam, Karunakaran; Subbarao, Krishna V

    2011-08-01

    Verticillium wilt of lettuce caused by Verticillium dahliae can cause severe economic damage to lettuce producers. Complete resistance to race 1 isolates is available in Lactuca sativa cultivar (cv.) La Brillante and understanding the genetic basis of this resistance will aid development of new resistant cultivars. F(1) and F(2) families from crosses between La Brillante and three iceberg cultivars as well as a recombinant inbred line population derived from L. sativa cv. Salinas 88 × La Brillante were evaluated for disease incidence and disease severity in replicated greenhouse and field experiments. One hundred and six molecular markers were used to generate a genetic map from Salinas 88 × La Brillante and for detection of quantitative trait loci. Segregation was consistent with a single dominant gene of major effect which we are naming Verticillium resistance 1 (Vr1). The gene described large portions of the phenotypic variance (R(2) = 0.49-0.68) and was mapped to linkage group 9 coincident with an expressed sequence tag marker (QGD8I16.yg.ab1) that has sequence similarity with the Ve gene that confers resistance to V. dahliae race 1 in tomato. The simple inheritance of resistance indicates that breeding procedures designed for single genes will be applicable for developing resistant cultivars. QGD8I16.yg.ab1 is a good candidate for functional analysis and development of markers suitable for marker-assisted selection.

  10. Inactivation of sclerotia of Rhizoctonia solani on potato tubers by Verticillium biguttatum, a soil-borne mycoparasite

    NARCIS (Netherlands)

    Jager, G.; Velvis, H.

    1988-01-01

    Experiments in the laboratory and on farms with potato tubers in storages are described in which sclerotia of Rhizoctonia solani were inactivated after inoculation of infected tubers with a suspension of conidia and hyphal fragments of Verticillium biguttatum

  11. SSH reveals a linkage between a senescence-associated protease and Verticillium wilt symptom development in lettuce (Lactuca sativa)

    Science.gov (United States)

    Suppression subtractive hybridization (SSH) was employed to identify lettuce (Lactuca sativa) genes that are differentially expressed in symptomatic leaves infected with Verticillium dahliae. Genes expressed only in symptomatic leaves included those with homology to pathogenesis-related (PR) protei...

  12. Overexpression of 3-deoxy-7-phosphoheptulonate synthase gene from Gossypium hirsutum enhances Arabidopsis resistance to Verticillium wilt.

    Science.gov (United States)

    Yang, Jun; Ji, Lianlian; Wang, Xingfen; Zhang, Yan; Wu, Lizhu; Yang, Yingna; Ma, Zhiying

    2015-08-01

    Expression of DHS1 in cotton is induced upon infection by Verticillium dahliae , and overexpression of GhDHS1 endows transgenic Arabidopsis plants excellent Verticillium resistance. Verticillium wilt is caused by a soil-borne fungus Verticillium dahliae. Resistance in most cotton cultivars is either scarce or unavailable, making Verticillium wilt a major obstacle in cotton production. Here, we identified a 3-deoxy-7-phosphoheptulonate synthase (DHS, EC 4.1.2.15) gene from Gossypium hirsutum, named GhDHS1. Its 1620 bp open reading frame encodes a putative 59.4 kDa protein. Phylogenetic analysis indicated that GhDHS1 is clustered in a clade with potato and tomato DHSs that can be induced by wounding and elicitors, respectively. Expression analysis demonstrated that GhDHS1 is constitutively expressed in cotton roots and stems, but transcripts are rare or non-existent in the leaves. Subcellular localization showed that GhDHS1 occurs in the plastids. When plants of three cultivars were inoculated with V. dahliae, DHS1 expression was more significantly up-regulated in the roots of resistant G. barbadense cv. Pima90-53 and G. hirsutum cv. Jimian20 than in the susceptible G. hirsutum cv. Han208. This suggested that DHS1 is involved in the cotton resistance to Verticillium wilt. Furthermore, GhDHS1 overexpressing transgenic lines of Arabidopsis were developed via Agrobacterium tumefaciens-mediated transformation. Compared with the untransformed WT (wild type), these transgenic plants showed excellent Verticillium wilt resistance with a significantly lower disease index. The overexpressing transgenic lines also had significantly longer primary roots and greatly increased xylem areas under V. dahliae infection. Overall, our results indicate that GhDHS1 performs a role in the cotton resistance to V. dahliae and would be potential to breeding cottons of Verticillium wilt resistance.

  13. Biological control of Rhizoctonia solani in potato by antagonists : field testing of the effect of inoculation of seed tubers with Verticillium biguttatum and other antagonists in 1981 and 1982

    NARCIS (Netherlands)

    Jager, G.; Velvis, H.

    1983-01-01

    Onderzoek naar de biologische bestrijding van Rhizoctonia solani in aardappelen op verschillende grondsoorten (klei, zavel en zand) door middel van inoculatie van de poters met de schimmel Verticillium biguttatum en andere antagonisten, inklusief Azotobacter chroococcum. Verticillium biguttatum gaf

  14. Frequency of Verticillium Species in Commercial Spinach Fields and Transmission of V. dahliae from Spinach to Subsequent Lettuce Crops.

    Science.gov (United States)

    Short, D P G; Gurung, S; Koike, S T; Klosterman, S J; Subbarao, K V

    2015-01-01

    Verticillium wilt caused by V. dahliae is a devastating disease of lettuce in California (CA). The disease is currently restricted to a small geographic area in central coastal CA, even though cropping patterns in other coastal lettuce production regions in the state are similar. Infested spinach seed has been implicated in the introduction of V. dahliae into lettuce fields but direct evidence linking this inoculum to wilt epidemics in lettuce is lacking. In this study, 100 commercial spinach fields in four coastal CA counties were surveyed to evaluate the frequency of Verticillium species recovered from spinach seedlings and the area under spinach production in each county was assessed. Regardless of the county, V. isaacii was the most frequently isolated species from spinach followed by V. dahliae and, less frequently, V. klebahnii. The frequency of recovery of Verticillium species was unrelated to the occurrence of Verticillium wilt on lettuce in the four counties but was related to the area under spinach production in individual counties. The transmission of V. dahliae from infested spinach seeds to lettuce was investigated in microplots. Verticillium wilt developed on lettuce following two or three plantings of Verticillium-infested spinach, in independent experiments. The pathogen recovered from the infected lettuce from microplots was confirmed as V. dahliae by polymerase chain reaction assays. In a greenhouse study, transmission of a green fluorescence protein-tagged mutant strain of V. dahliae from spinach to lettuce roots was demonstrated, after two cycles of incorporation of infected spinach residue into the soil. This study presents conclusive evidence that V. dahliae introduced via spinach seed can cause Verticillium wilt in lettuce.

  15. The lecanindoles, nonsteroidal progestins from the terrestrial fungus Verticillium lecanii 6144.

    Science.gov (United States)

    Roll, Deborah M; Barbieri, Laurel R; Bigelis, Ramunas; McDonald, Leonard A; Arias, Daniel A; Chang, Li-Ping; Singh, Maya P; Luckman, Scott W; Berrodin, Thomas J; Yudt, Matthew R

    2009-11-01

    Four new indolosesquiterpenes, lecanindoles A-D (1-4), were isolated from fermentations of the terrestrial fungus Verticillium lecanii 6144. The structures of compounds 1-4 were elucidated from analysis of spectroscopic data. Compound 2 was reduced to give 4 and its isomer 5. Compound 4 was found to be a potent and selective progesterone receptor agonist with an EC50 of 1.1 +/- 0.4 nM in a cell-based luciferase reporter assay.

  16. Soil temperature determines the reaction of olive cultivars to Verticillium dahliae pathotypes.

    Science.gov (United States)

    Calderón, Rocío; Lucena, Carlos; Trapero-Casas, José L; Zarco-Tejada, Pablo J; Navas-Cortés, Juan A

    2014-01-01

    Development of Verticillium wilt in olive, caused by the soil-borne fungus Verticillium dahliae, can be influenced by biotic and environmental factors. In this study we modeled i) the combined effects of biotic factors (i.e., pathotype virulence and cultivar susceptibility) and abiotic factors (i.e., soil temperature) on disease development and ii) the relationship between disease severity and several remote sensing parameters and plant stress indicators. Plants of Arbequina and Picual olive cultivars inoculated with isolates of defoliating and non-defoliating V. dahliae pathotypes were grown in soil tanks with a range of soil temperatures from 16 to 32°C. Disease progression was correlated with plant stress parameters (i.e., leaf temperature, steady-state chlorophyll fluorescence, photochemical reflectance index, chlorophyll content, and ethylene production) and plant growth-related parameters (i.e., canopy length and dry weight). Disease development in plants infected with the defoliating pathotype was faster and more severe in Picual. Models estimated that infection with the defoliating pathotype was promoted by soil temperatures in a range of 16 to 24°C in cv. Picual and of 20 to 24°C in cv. Arbequina. In the non-defoliating pathotype, soil temperatures ranging from 16 to 20°C were estimated to be most favorable for infection. The relationship between stress-related parameters and disease severity determined by multinomial logistic regression and classification trees was able to detect the effects of V. dahliae infection and colonization on water flow that eventually cause water stress. Chlorophyll content, steady-state chlorophyll fluorescence, and leaf temperature were the best indicators for Verticillium wilt detection at early stages of disease development, while ethylene production and photochemical reflectance index were indicators for disease detection at advanced stages. These results provide a better understanding of the differential geographic

  17. Biocontrol potential of Trichoderma harzianum in controlling wilt disease of pistachio caused by Verticillium dahliae

    Directory of Open Access Journals (Sweden)

    Fotoohiyan Zeinab

    2017-06-01

    Full Text Available Verticillium wilt caused by Verticillium dahliae, is one of the most devastating diseases in pistachio orchards in the world including Iran. In search for an effective non-chemical strategy for the management of this disease, we evaluated the biocontrol potential of Trichoderma harzianum isolates obtained from the rhizosphere of healthy pistachio trees in different locations of the Kerman province of Iran against V. dahliae under laboratory and greenhouse conditions. Dual culture tests in the laboratory were conducted in a completely randomized design using 72 T. harzianum isolates. Twenty isolates showed the highest in vitro antagonistic activity. The results indicated that all 20 isolates were capable of inhibiting the mycelial growth of V. dahliae significantly. Among them, isolates Tr8 and Tr19 were the most effective by 88.89% and 85.12% inhibition, respectively. Extracted cell free metabolites of all effective isolates also inhibited the growth of V. dahliae in the culture medium significantly. According to the results, isolates Tr4 and Tr6 inhibited fungal pathogen growth by 94.94% and 88.15% respectively, through production of non-volatile metabolites. In the evaluation of volatile metabolites, isolates Tr5 and Tr4 were the most effective by 26.27% and 24.49% growth inhibition, respectively. Based on the results of the in vitro experiments, the five most effective isolates were selected for evaluation under greenhouse conditions for their biocontrol potential in controlling Verticillium wilt of pistachio. Results of the greenhouse, (in vivo experiments were positive and indicated that the occurrence of wilt disease in plants treated with the antagonists alone or in combination with pathogenic fungus was lower than in plants inoculated with pathogen alone. The overall results of this study suggest that Trichoderma fungal antagonist may be an effective biocontrol agent for the control of Verticillium wilt of pistachio.

  18. Successful strategy for the selection of new strawberry-associated rhizobacteria antagonistic to Verticillium wilt.

    Science.gov (United States)

    Berg, G; Kurze, S; Buchner, A; Wellington, E M; Smalla, K

    2000-12-01

    In order to isolate and characterize new strawberry-associated bacteria antagonistic to the soil-borne pathogenic fungus Verticillium dahliae Kleb., rhizobacterial populations from two different strawberry species, Greenish Strawberry (Fragaria viridis) and Garden Strawberry (F. x ananassa) obtained after plating onto King's B and glycerol-arginine agar, were screened for in vitro antagonism toward V. dahliae. The proportion of isolates with antifungal activity determined in in vitro assay against V. dahliae was higher for the Garden Strawberry than for the Greenish Strawberry. From 300 isolates, 20 isolates with strong antifungal activity were selected characterized by physiological profiling and molecular fingerprinting methods. Diversity among the isolates was characterized with molecular fingerprints using amplified ribosomal DNA restriction analysis (ARDRA) and the more discriminating BOX-PCR fingerprint method. The physiological profiles were well correlated with molecular fingerprinting pattern analysis. Significant reduction of Verticillium wilt by bacterial dipping bath treatment was shown in the greenhouse and in fields naturally infested by V. dahliae. The relative increase of yield ranged from 117% (Streptomyces albidoflavus S1) to 344% (Pseudomonas fluorescens P10) in greenhouse trials, and 113% (Streptomyces albidoflavus S1) to 247% (Pseudomonas fluorescens P6) in field trials. Evaluation resulted in the selection of three effective biocontrol agents (Pseudomonas fluorescens P6, P10, and Streptomyces diastatochromogenes S9) antagonistic to the Verticillium wilt pathogen.

  19. Verticillium transcription activator of adhesion Vta2 suppresses microsclerotia formation and is required for systemic infection of plant roots.

    Science.gov (United States)

    Tran, Van-Tuan; Braus-Stromeyer, Susanna A; Kusch, Harald; Reusche, Michael; Kaever, Alexander; Kühn, Anika; Valerius, Oliver; Landesfeind, Manuel; Aßhauer, Kathrin; Tech, Maike; Hoff, Katharina; Pena-Centeno, Tonatiuh; Stanke, Mario; Lipka, Volker; Braus, Gerhard H

    2014-04-01

    Six transcription regulatory genes of the Verticillium plant pathogen, which reprogrammed nonadherent budding yeasts for adhesion, were isolated by a genetic screen to identify control elements for early plant infection. Verticillium transcription activator of adhesion Vta2 is highly conserved in filamentous fungi but not present in yeasts. The Magnaporthe grisea ortholog conidiation regulator Con7 controls the formation of appressoria which are absent in Verticillium species. Vta2 was analyzed by using genetics, cell biology, transcriptomics, secretome proteomics and plant pathogenicity assays. Nuclear Vta2 activates the expression of the adhesin-encoding yeast flocculin genes FLO1 and FLO11. Vta2 is required for fungal growth of Verticillium where it is a positive regulator of conidiation. Vta2 is mandatory for accurate timing and suppression of microsclerotia as resting structures. Vta2 controls expression of 270 transcripts, including 10 putative genes for adhesins and 57 for secreted proteins. Vta2 controls the level of 125 secreted proteins, including putative adhesins or effector molecules and a secreted catalase-peroxidase. Vta2 is a major regulator of fungal pathogenesis, and controls host-plant root infection and H2 O2 detoxification. Verticillium impaired in Vta2 is unable to colonize plants and induce disease symptoms. Vta2 represents an interesting target for controlling the growth and development of these vascular pathogens. © 2014 The Authors. New Phytologist © 2014 New Phytologist Trust.

  20. Efficacy of Seaweed Concentrate from Ecklonia maxima (Osbeck and Conventional Fungicides in the Control of Verticillium Wilt of Pepper

    Directory of Open Access Journals (Sweden)

    Emil Rekanović

    2010-01-01

    Full Text Available In order to control the causal agent of Verticillium wilt of pepper (Verticillium dahliae,the efficacy of two conventional fungicides, thiophanate-methyl and carbendazim,and seaweed concentrate (SWC from Ecklonia maxima was evaluated in greenhouse conditions. Pepper plants were inoculated with selected V. dahliae isolate in the stage of more than nine fully developed leaves on primary stem. The tested fungicides and SWC were applied three days before inoculation of pepper plants. Carbendazim was the most efficient fungicide among tested substances (69.64%. SWC proved to be more effective when applied at 1.0% concentarion (41.96%. The use of thiophanate-methyl provided good Verticillium wilt control in pepper (60.71%. SWC was less efficient than thiophanate-methyl and carbendazim, but still significantly better compared to the disease control plot.

  1. The Ectopic Overexpression of the Cotton Ve1 and Ve2-Homolog Sequences Leads to Resistance Response to Verticillium Wilt in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Jieyin Chen

    2017-05-01

    Full Text Available Verticillium wilt, caused by the Verticillium dahliae phytopathogen, is a devastating disease affecting many economically important crops. A receptor-like protein (RLP gene, Ve1, has been reported to confer resistance to V. dahliae in tomato plants, but few genes have been found to be involved in cotton Verticillium wilt resistance. Here, we cloned two RLP gene homologs, Gossypium barbadense resistance gene to Verticillium dahliae 1 (GbaVd1 and GbaVd2, from the Verticillium wilt-resistant cultivar G. barbadense cv. Hai7124. GbaVd1 and GbaVd2 display sequence divergence, but both encode typical RLPs. Virus-induced gene silencing of GbaVd1 or GbaVd2 compromised the resistance of cotton to V. dahliae, and both genes conferred Verticillium wilt resistance after interfamily transfer into Arabidopsis. Microarray analysis revealed that GbaVd1 and GbaVd2 participate in Verticillium wilt resistance in Arabidopsis through activation of defense responses, including the endocytosis process, signaling factors, transcription factors and reinforcement of the cell wall, as demonstrated by lignification in Arabidopsis transgenic plants. In addition, microarray analysis showed that GbaVd1 and GbaVd2 differentially mediate resistance signaling and activation of defense responses after overexpression in Arabidopsis. Thus, GbaVd1 and GbaVd2 encode RLPs and act as disease resistance genes that mediate the defense response against V. dahliae in cotton.

  2. Arbuscular mycorrhizal fungi (AMF) as bio protector agents against wilt induced by Verticillium spp. in pepper

    Energy Technology Data Exchange (ETDEWEB)

    Goicoechea, N.; Garmendia, I.; Sanchez-Diaz, M.; Aguirreolea, J.

    2010-07-01

    Verticillium dahliae Kleb. is a vascular pathogen that alters water status and growth of pepper plants and causes drastic reductions in yield. Its control is difficult because it can survive in field soil for several years. The application of arbuscular mycorrhizal fungi (AMF) as bio protector agents against V. dahliae is an alternative to the use of chemicals which, in addition, is more respectful with the environment. The establishment of the mutualistic association of plant roots and AMF involves a continuous cellular and molecular dialogue between both symbionts that includes the pre activation of plant defense responses that may enhance the resistance or tolerance of mycorrhizal plants to soil-borne pathogens. Some AMF can improve the resistance of Capsicum annuum L. against V. dahliae. This is especially relevant for pepper cultivars (i.e. cv. Piquillo) that exhibit high susceptibility to this pathogen. Compared with non-mycorrhizal plants, mycorrhizal pepper can exhibit more balanced antioxidant metabolism in leaves along the first month after pathogen inoculation, which may contribute to delay both the development of disease symptoms and the decrease of photosynthesis in Verticillium-inoculated plants with the subsequent benefit for yield. In stems, mycorrhizal pepper show earlier and higher deposition of lignin in xylem vessels than non mycorrhizal plants, even in absence of the pathogen. Moreover, AMF can induce new isoforms of acidic chitinases and superoxide dismutase in roots. Mycorrhizal-specific induction of these enzymatic activities together with enhanced peroxidase and phenylalanine ammonia-lyase in roots may also be involved in the bio protection of Verticillium-induced wilt in pepper by AMF. (Author) 81 refs.

  3. Biocontrol of verticillium wilt and colonization of cotton plants by an endophytic bacterial isolate.

    Science.gov (United States)

    Li, C-H; Shi, L; Han, Q; Hu, H-L; Zhao, M-W; Tang, C-M; Li, S-P

    2012-09-01

    To explore biocontrol potential of 39 DAEB isolates (doubly antagonistic towards both Verticillium dahliae Kleb and Fusarium oxysporum) against verticillium wilt of cotton and to elucidate colonization and category characteristics of an endophytic bacterium with significant biocontrol activity. Thirty-nine antagonistic endophytic bacteria strains were tested for their ability to control verticillium wilt in cotton plants caused by a defoliating pathotype of V. dahliae 107 in cotton under controlled conditions. The biocontrol trial revealed that an endophytic bacterium, designated HA02, showed a significant biocontrol activity to V. dahliae 107. After cotton seedlings were inoculated with a gfp gene-tagged HA02 (HA02-gfp), HA02-gfp populations were higher in the root than in the stem; in addition, the HA02-gfp was distributed in the maturation zone of cotton root. Furthermore, HA02-gfp also colonized seedlings of maize, rape and soybean after the bacteria inoculation. Phylogenetic trees based on 16S rDNA sequences combined with morphological, physiological and identification showed that the bacterium belongs to the Enterobacter genus. Our results showed that only 1 of 39 DAEB isolates demonstrated more efficient biocontrol potential towards V. dahliae 107 in greenhouse and field trials. HA02-gfp mainly colonized cotton in roots. In addition, we quantitatively observed HA02 colonization in other hosts. HA02 belongs to the Enterobacter genus. This is the first study on biocontrol to defoliating pathotype of V. dahliae Kleb by endophytic bacteria. The HA02 showed effective biocontrol to V. dahliae 107 in greenhouse and field trials. Furthermore, we assessed the quantitative and qualitative colonization of HA02 in cotton seedlings. Our study provides basic information to further explore managing strategies to control this critical disease. © 2012 The Authors Journal of Applied Microbiology © 2012 The Society for Applied Microbiology.

  4. Companion cropping with potato onion enhances the disease resistance of tomato against Verticillium dahliae

    Directory of Open Access Journals (Sweden)

    Xuepeng eFu

    2015-09-01

    Full Text Available Intercropping could alleviate soil-borne diseases, however, few studies focused on the immunity of the host plant induced by the interspecific interactions. To test whether or not intercropping could enhance the disease resistance of host plant, we investigated the effect of companion cropping with potato onion on tomato Verticillium wilt caused by Verticillium dahliae (V. dahliae. To investigate the mechanisms, the root exudates were collected from tomato and potato onion which were grown together or separately, and were used to examine the antifungal activities against V. dahliae in vitro, respectively. Furthermore, RNA-seq was used to examine the expression pattern of genes related to disease resistance in tomato companied with potato onion compared to that in tomato grown alone, under the condition of infection with V. dahliae. The results showed that companion cropping with potato onion could alleviate the incidence and severity of tomato Verticillium wilt. The further studies revealed that the root exudates from tomato companied with potato onion significantly inhibited the mycelia growth and spore germination of V. dahliae. However, there were no significant effects on these two measurements for the root exudates from potato onion grown alone or from potato onion grown with tomato. RNA-seq data analysis showed the disease defense genes associated with pathogenesis-related proteins, biosynthesis of lignin, hormone metabolism and signal transduction were expressed much higher in the tomato companied with potato onion than those in the tomato grown alone, which indicated that these defense genes play important roles in tomato against V. dahliae infection, and meant that the disease resistance of tomato against V. dahliae was enhanced in the companion copping with potato onion. We proposed that companion cropping with potato onion could enhance the disease resistance of tomato against V. dahliae by regulating the expression of genes related

  5. Companion cropping with potato onion enhances the disease resistance of tomato against Verticillium dahliae.

    Science.gov (United States)

    Fu, Xuepeng; Wu, Xia; Zhou, Xingang; Liu, Shouwei; Shen, Yanhui; Wu, Fengzhi

    2015-01-01

    Intercropping could alleviate soil-borne diseases, however, few studies focused on the immunity of the host plant induced by the interspecific interactions. To test whether or not intercropping could enhance the disease resistance of host plant, we investigated the effect of companion cropping with potato onion on tomato Verticillium wilt caused by Verticillium dahliae (V. dahliae). To investigate the mechanisms, the root exudates were collected from tomato and potato onion which were grown together or separately, and were used to examine the antifungal activities against V. dahliae in vitro, respectively. Furthermore, RNA-seq was used to examine the expression pattern of genes related to disease resistance in tomato companied with potato onion compared to that in tomato grown alone, under the condition of infection with V. dahliae. The results showed that companion cropping with potato onion could alleviate the incidence and severity of tomato Verticillium wilt. The further studies revealed that the root exudates from tomato companied with potato onion significantly inhibited the mycelia growth and spore germination of V. dahliae. However, there were no significant effects on these two measurements for the root exudates from potato onion grown alone or from potato onion grown with tomato. RNA-seq data analysis showed the disease defense genes associated with pathogenesis-related proteins, biosynthesis of lignin, hormone metabolism and signal transduction were expressed much higher in the tomato companied with potato onion than those in the tomato grown alone, which indicated that these defense genes play important roles in tomato against V. dahliae infection, and meant that the disease resistance of tomato against V. dahliae was enhanced in the companion copping with potato onion. We proposed that companion cropping with potato onion could enhance the disease resistance of tomato against V. dahliae by regulating the expression of genes related to disease

  6. Potential of Endophytic Fungi Isolated from Cotton Roots for Biological Control against Verticillium Wilt Disease.

    Science.gov (United States)

    Yuan, Yuan; Feng, Hongjie; Wang, Lingfei; Li, Zhifang; Shi, Yongqiang; Zhao, LiHong; Feng, Zili; Zhu, Heqin

    2017-01-01

    Verticillium wilt is a soil-borne disease, and severely limits the development of cotton production. To investigate the role of endophytic fungi on Verticillium wilt, CEF-818 (Penicillium simplicissimum), CEF-714 (Leptosphaeria sp.), CEF-642 (Talaromyces flavus.) and CEF-193 (Acremonium sp.) isolated from cotton roots were used to assess their effects against cotton wilt disease caused by a defoliating V. dahliae strain Vd080. In the greenhouse, all treatments significantly reduced disease incidence and disease index, with the control efficacy ranging from 26% (CEF-642) to 67% (CEF-818) at 25 days (d) after inoculation. In the disease nursery, compared to controls (with disease incidence of 33.8% and disease index of 31), CEF-818, CEF-193, CEF-714 and CEF-642 provided a protection effect of 69.5%, 69.2%, 54.6% and 45.7%, respectively. Especially, CEF-818 and CEF-714 still provided well protection against Verticillium wilt with 46.9% and 56.6% or 14.3% and 33.7% at the first peak of the disease in heavily infected field, respectively (in early July). These results indicated that these endophytes not only delayed but also reduced wilt symptoms on cotton. In the harvest, the available cotton bolls of plant treated with CEF-818 and CEF-714 increased to 13.1, and 12.2, respectively. And the seed cotton yield significantly increased after seed bacterization with CEF-818 (3442.04 kg/ha) compared to untreated control (3207.51 kg/ha) by 7.3%. Furtherly, CEF-818 and CET-714 treatment increased transcript levels for PAL, PPO, POD, which leads to the increase of cotton defense reactions. Our results indicate that seed treatment of cotton plants with CEF-818 and CET-714 can help in the biocontrol of V. dahliae and improve seed cotton yield in cotton fields. This study provided a better understanding of cotton-endophyte interactions which will aid in developing effective biocontrol agents for Verticillium wilt of cotton in futhre.

  7. Potential of Endophytic Fungi Isolated from Cotton Roots for Biological Control against Verticillium Wilt Disease.

    Directory of Open Access Journals (Sweden)

    Yuan Yuan

    Full Text Available Verticillium wilt is a soil-borne disease, and severely limits the development of cotton production. To investigate the role of endophytic fungi on Verticillium wilt, CEF-818 (Penicillium simplicissimum, CEF-714 (Leptosphaeria sp., CEF-642 (Talaromyces flavus. and CEF-193 (Acremonium sp. isolated from cotton roots were used to assess their effects against cotton wilt disease caused by a defoliating V. dahliae strain Vd080. In the greenhouse, all treatments significantly reduced disease incidence and disease index, with the control efficacy ranging from 26% (CEF-642 to 67% (CEF-818 at 25 days (d after inoculation. In the disease nursery, compared to controls (with disease incidence of 33.8% and disease index of 31, CEF-818, CEF-193, CEF-714 and CEF-642 provided a protection effect of 69.5%, 69.2%, 54.6% and 45.7%, respectively. Especially, CEF-818 and CEF-714 still provided well protection against Verticillium wilt with 46.9% and 56.6% or 14.3% and 33.7% at the first peak of the disease in heavily infected field, respectively (in early July. These results indicated that these endophytes not only delayed but also reduced wilt symptoms on cotton. In the harvest, the available cotton bolls of plant treated with CEF-818 and CEF-714 increased to 13.1, and 12.2, respectively. And the seed cotton yield significantly increased after seed bacterization with CEF-818 (3442.04 kg/ha compared to untreated control (3207.51 kg/ha by 7.3%. Furtherly, CEF-818 and CET-714 treatment increased transcript levels for PAL, PPO, POD, which leads to the increase of cotton defense reactions. Our results indicate that seed treatment of cotton plants with CEF-818 and CET-714 can help in the biocontrol of V. dahliae and improve seed cotton yield in cotton fields. This study provided a better understanding of cotton-endophyte interactions which will aid in developing effective biocontrol agents for Verticillium wilt of cotton in futhre.

  8. Paecilomyces lilacinus and Verticillium chlamydosporium Fungi as Biological Control of Fasciolosis

    Directory of Open Access Journals (Sweden)

    Riza Zainuddin Ahmad

    2013-09-01

    Full Text Available Fasciolosis is a worm disease caused of Fasciola gigantica and an important problem in husbandry especially for cattle. Controlling of this worm disease can be conducted by prevention and treatment. The use of antihelminthic is commonly causes a resistance problem. Natural control by mold such as Paecilomyces lilacinus and Verticillium chlamydosporium can be applied to reduce egg of F. gigantica. Although it was recently found, in vitro study gave satisfied result. This gives a new hope in controlling the disease although the extend application still needs to be studied. This paper discussed about the use of P. lilacinus and V. chlamydosporium for reducing F. gigantica population.

  9. Soil temperature determines the reaction of olive cultivars to Verticillium dahliae pathotypes.

    Directory of Open Access Journals (Sweden)

    Rocío Calderón

    Full Text Available Development of Verticillium wilt in olive, caused by the soil-borne fungus Verticillium dahliae, can be influenced by biotic and environmental factors. In this study we modeled i the combined effects of biotic factors (i.e., pathotype virulence and cultivar susceptibility and abiotic factors (i.e., soil temperature on disease development and ii the relationship between disease severity and several remote sensing parameters and plant stress indicators.Plants of Arbequina and Picual olive cultivars inoculated with isolates of defoliating and non-defoliating V. dahliae pathotypes were grown in soil tanks with a range of soil temperatures from 16 to 32°C. Disease progression was correlated with plant stress parameters (i.e., leaf temperature, steady-state chlorophyll fluorescence, photochemical reflectance index, chlorophyll content, and ethylene production and plant growth-related parameters (i.e., canopy length and dry weight.Disease development in plants infected with the defoliating pathotype was faster and more severe in Picual. Models estimated that infection with the defoliating pathotype was promoted by soil temperatures in a range of 16 to 24°C in cv. Picual and of 20 to 24°C in cv. Arbequina. In the non-defoliating pathotype, soil temperatures ranging from 16 to 20°C were estimated to be most favorable for infection. The relationship between stress-related parameters and disease severity determined by multinomial logistic regression and classification trees was able to detect the effects of V. dahliae infection and colonization on water flow that eventually cause water stress.Chlorophyll content, steady-state chlorophyll fluorescence, and leaf temperature were the best indicators for Verticillium wilt detection at early stages of disease development, while ethylene production and photochemical reflectance index were indicators for disease detection at advanced stages. These results provide a better understanding of the differential

  10. Data integration and knowledge management to facilitate research on plant-pathogen interactions: case study Solanum tuberosum – Verticillium

    Science.gov (United States)

    Verticillium wilt is an important disease causing considerable economic losses in potato production globally. Soil and environmental conditions affect symptom expression and the effect of the disease on yield. A ten year field trial has been conducted in order to better understand the dynamics of wi...

  11. Microscopic observations on the interaction of the mycoparasite Verticillium biguttatum with Rhizoctonia solani and other soil-borne fungi

    NARCIS (Netherlands)

    Boogert, P.H.J.F. van den; Reinartz, H.; Sjollema, K.A.; Veenhuis, M.

    The mycoparasitic interactions of Verticillium biguttatum with Rhizoctonia solani and with a variety of other soil-borne fungi were investigated in dual cultures. V. biguttatum interacted with various soil fungi by appressed growth along the host hyphae and infrequent penetrations. Intracellular

  12. Transcriptomic analysis of the Olea europaea L. roots during the Verticillium dahliae early infection process

    DEFF Research Database (Denmark)

    Jiménez-Ruiz, Jaime; Pérez, Maria De la O Leyva; Schilirò, Elisabetta

    2017-01-01

    Olive cultivation is affected by a wide range of biotic constraints. Verticillium wilt of olive is one of the most devastating diseases affecting this woody crop, inflicting major economic losses in many areas, particularly within the Mediterranean Basin. Little is known about gene-expression cha...

  13. Media for efficient generating nitrate- - nonutilizing (NIT) mutants of Verticillium dahliae, Colletotrichum gloeosporioides, Colletotrichum lindemuthianum and Fusarium oxysporum.

    NARCIS (Netherlands)

    Rataj-Guranowska, M.; Pieczul, K.; Nowak, E.; Hiemstra, J.A.; Drapikowska, M.

    2001-01-01

    The effect of several media amended wit potassium chlorate (1.5% and 6%) on generation of nit mutants, especially nit M mutants from Verticillium dahliae, Colletotrichum gloeosporioides, Colletotrichum lindemuthianum and Fusarium oxysporum were studied. For all species minimal medium with 6%

  14. Improvement of the efficacy of Verticillium lecanii used in biocontrol of Sphaerotheca fuliginea by addition of oil formulations

    NARCIS (Netherlands)

    Verhaar, M.A.; Hijwegen, T.; Zadoks, J.C.

    1999-01-01

    Biocontrol of cucumber powdery mildew, Sphaerotheca fuliginea, by Verticillium lecanii is seriously hampered at low humidities. The effect is especially marked at low humidity (60% RH) during the three hours following the application of V. lecanii spores suspended in water. Formulations of V.

  15. Management of Verticillium wilt of potato with disease-suppressive green manures and as affected by previous cropping history

    Science.gov (United States)

    The ability of potential disease-suppressive rotation crops to reduce potato disease problems and increase crop productivity in a field severely infested with Verticillium wilt was evaluated over three field seasons in Maine. Disease-suppressive rotation treatments consisted of 1) a high glucosinola...

  16. Constitutive expression of a novel antimicrobial protein, Hcm1, confers resistance to both Verticillium and Fusarium wilts in cotton.

    Science.gov (United States)

    Zhang, Zhiyuan; Zhao, Jun; Ding, Lingyun; Zou, Lifang; Li, Yurong; Chen, Gongyou; Zhang, Tianzhen

    2016-02-09

    Fusarium and Verticillium wilts, two of the most important diseases in cotton, pose serious threats to cotton production. Here we introduced a novel antimicrobial protein Hcm1, which comprised harpin protein from Xanthomonas oryzae pv. oryzicola (Xoc), and the chimeric protein, cecropin A-melittin, into cotton. The transgenic cotton lines with stable Hcm1 expression showed a higher resistance to Verticillium and Fusarium wilts both in greenhouse and field trials compared to controls. Hcm1 enabled the transgenic cotton to produced a microscopic hypersensitive response (micro-HR), reactive oxygen species (ROS) burst, and caused the activation of pathogenesis-related (PR) genes in response to biotic stress, indicating that the transgenic cotton was in a primed state and ready to protect the host from pathogenic infection. Simultaneously, Hcm1 protein inhibited the growth of Verticillium dahliae (V. dahliae) and Fusarium oxysporum (F. oxysporum) in vitro. The spread of fungal biomass was also inhibited in vivo since the V. dahliae biomass was decreased dramatically in transgenic cotton plants after inoculation with V. dahliae. Together, these results demonstrate that Hcm1 could activate innate immunity and inhibit the growth of V. dahliae and F. oxysporum to protect cotton against Verticillium and Fusarium wilts.

  17. Enhanced production of microsclerotia in recalcitrant Verticillium dahliae isolates and its use for inoculation of olive plants.

    Science.gov (United States)

    Varo, A; Raya-Ortega, M C; Trapero, A

    2016-08-01

    The optimization of a simple protocol for the mass production of viable microsclerotia (MS) of Verticillium spp., even for recalcitrant isolates, to the inoculation of olive cuttings. Four Verticillium spp. isolates were characterized by growth rate and morphology. Then, the production ability and the viability of MS over time were assessed in seven solid culture media and five aqueous media. The best culture medium, according to the quantity and the quality (size) of the MS produced, was the alkaline-modified sodium polipectate (AMSP) aqueous medium. The MS viability was higher in peat moss substrates. Finally, the MS obtained in this work were infective causing 100% incidence of Verticillium wilt (VW) disease in inoculated olive plants. This study demonstrates that the modified sodium polipectate medium amended with 0·1% agar is the most suitable for the production of MS of Verticillium dahliae isolates that have lost the ability to produce MS in standard culture media. Mass production of MS for artificial infestation of soil is critical to the study of epidemiological and control aspects of the VW. To overcome the failure in the production of MS in recalcitrant isolates, a culture media was optimized and a successful plant inoculation experiment was carried out with artificial MS. © 2016 The Society for Applied Microbiology.

  18. [Inhibitory effects of natural plant extracts on Verticillium albo-atrum].

    Science.gov (United States)

    Zhang, Shuhong; Zhou, Baoli; Zhang, Lei; Fu, Yawen

    2006-06-01

    This paper studied the inhibitory effects of 54 kinds of ethanol-extracted plant solutions on Verticillium albo-atrum. The results showed that 15 kinds of these extracts could inhibit the growth of verticillium albo-atrum mycelium, with an inhibitory rate more than 50%, among which, the inhibitory rate of Asarum sieboldii, Coptis chinensis, Magnolia officinalis, Acacia catechu, Sophora flavescens, Glycyrrhiza uralensis, Cnidium monnieri, Platycodon grandiflorum and Allium. cepa. extracts was higher than 65%, and that of Cnidium monnieri extract reached 86.84%. A total of 16 kinds of plant extracts decreased the spore germination of V. albo-atrum, with the inhibitory rate higher than 70%, and there were 7 kinds of plant extracts whose inhibitory rate reached 95%. Almost no spore bourgeon was found after treated with Asarum sieboldii, Coptis chinensis, and Magnolia officinalis extracts. The extract of Acacia catechu did not inhibit the growth of mycelium, but restrained the spore germination by 100%. Cnidium monnieri extract could strongly inhibit the growth of mycelium, but had a less effect on spore germination rate (only by 11.3%). The active substances found in natural plant extracts which had the inhibitory effects on pathogen brought us a new and promising method to deal with V. albo-atrum and other vegetable diseases.

  19. Analysis of upland cotton (Gossypium hirsutum) response to Verticillium dahliae inoculation by transcriptome sequencing.

    Science.gov (United States)

    Shao, B X; Zhao, Y L; Chen, W; Wang, H M; Guo, Z J; Gong, H Y; Sang, X H; Cui, Y L; Wang, C H

    2015-10-27

    Verticillium wilt is one of the main diseases in cotton (Gossypium hirsutum), severely reduces yield and fiber quality, and is difficult to be con-trolled effectively. At present, the molecular mechanism that confers resistance to this disease is unclear. Transcriptome sequencing is an important method to detect resistance genes, explore metabolic pathways, and study resistance mechanisms. In this study, the transcriptome of a disease-resistant inbred cot-ton line inoculated with Verticillium dahliae was sequenced. A total of 126,402 unigenes were obtained using de novo assembly and data analysis, 99,712 (78.88%) of which were annotated into the Nr, Nt, Swiss-Prot, KEGG, COG, and GO databases. The expression patterns of 16 candidate disease-resis-tance genes showed that some genes were upregulated soon after V. dahliae inoculation and others were upregulated later, which may indicate instanta-neous basal defense and lagged specific defense, respectively. We conducted a preliminary analysis of the transcriptome database, which will contribute to further research regarding the cloning of disease-resistance genes.

  20. Comparative Proteomic Analysis of Gossypium thurberi in Response to Verticillium dahliae Inoculation

    Directory of Open Access Journals (Sweden)

    Weiping Fang

    2015-10-01

    Full Text Available Verticillium wilt is threatening cotton productivity globally. This disease is caused by soil-borne Verticillium dahliae which directly infects cotton roots, and exclusively colonizes and occludes xylem vessels, finally resulting in necrosis, defoliation, and most severely, plant death. For the first time, iTRAQ (isobaric tags for relative and absolute quantification was applied to screen the differentially expressed proteins of Gossypium thurberi inoculated with V. dahliae. A total of 6533 proteins were identified from the roots of G. thurberi after inoculation with V. dahliae, and 396 showed up- and 279 down-regulated in comparison to a mock-inoculated roots. Of these identified proteins, the main functional groups were those involved in cell wall organization and reinforcement, disease-resistant chemicals of secondary metabolism, phytohormone signaling, pathogenesis-related proteins, and disease-resistant proteins. Physiological and biochemical analysis showed that peroxidase activity, which promotes the biosynthesis and accumulation of lignin, was induced early in the hypocotyl after inoculation with V. dahliae. Similarly, salicylic acid also accumulated significantly in hypocotyl of the seedlings after inoculation. These findings provide an important knowledge of the molecular events and regulatory networks occurring during G. thurberi-V. dahliae interaction, which may provide a foundation for breeding disease-resistance in cotton.

  1. Heterologous Expression of the Cotton NBS-LRR Gene GbaNA1 Enhances Verticillium Wilt Resistance in Arabidopsis

    Directory of Open Access Journals (Sweden)

    Nan-Yang Li

    2018-02-01

    Full Text Available Verticillium wilt caused by Verticillium dahliae results in severe losses in cotton, and is economically the most destructive disease of this crop. Improving genetic resistance is the cleanest and least expensive option to manage Verticillium wilt. Previously, we identified the island cotton NBS-LRR-encoding gene GbaNA1 that confers resistance to the highly virulent V. dahliae isolate Vd991. In this study, we expressed cotton GbaNA1 in the heterologous system of Arabidopsis thaliana and investigated the defense response mediated by GbaNA1 following inoculations with V. dahliae. Heterologous expression of GbaNA1 conferred Verticillium wilt resistance in A. thaliana. Moreover, overexpression of GbaNA1 enabled recovery of the resistance phenotype of A. thaliana mutants that had lost the function of GbaNA1 ortholog gene. Investigations of the defense response in A. thaliana showed that the reactive oxygen species (ROS production and the expression of genes associated with the ethylene signaling pathway were enhanced significantly following overexpression of GbaNA1. Intriguingly, overexpression of the GbaNA1 ortholog from Gossypium hirsutum (GhNA1 in A. thaliana did not induce the defense response of ROS production due to the premature termination of GhNA1, which lacks the encoded NB-ARC and LRR motifs. GbaNA1 therefore confers Verticillium wilt resistance in A. thaliana by the activation of ROS production and ethylene signaling. These results demonstrate the functional conservation of the NBS-LRR-encoding GbaNA1 in a heterologous system, and the mechanism of this resistance, both of which may prove valuable in incorporating GbaNA1-mediated resistance into other plant species.

  2. Genome-wide analysis of the gene families of resistance gene analogues in cotton and their response to Verticillium wilt.

    Science.gov (United States)

    Chen, Jie-Yin; Huang, Jin-Qun; Li, Nan-Yang; Ma, Xue-Feng; Wang, Jin-Long; Liu, Chuan; Liu, Yong-Feng; Liang, Yong; Bao, Yu-Ming; Dai, Xiao-Feng

    2015-06-19

    Gossypium raimondii is a Verticillium wilt-resistant cotton species whose genome encodes numerous disease resistance genes that play important roles in the defence against pathogens. However, the characteristics of resistance gene analogues (RGAs) and Verticillium dahliae response loci (VdRLs) have not been investigated on a global scale. In this study, the characteristics of RGA genes were systematically analysed using bioinformatics-driven methods. Moreover, the potential VdRLs involved in the defence response to Verticillium wilt were identified by RNA-seq and correlations with known resistance QTLs. The G. raimondii genome encodes 1004 RGA genes, and most of these genes cluster in homology groups based on high levels of similarity. Interestingly, nearly half of the RGA genes occurred in 26 RGA-gene-rich clusters (Rgrcs). The homology analysis showed that sequence exchanges and tandem duplications frequently occurred within Rgrcs, and segmental duplications took place among the different Rgrcs. An RNA-seq analysis showed that the RGA genes play roles in cotton defence responses, forming 26 VdRLs inside in the Rgrcs after being inoculated with V. dahliae. A correlation analysis found that 12 VdRLs were adjacent to the known Verticillium wilt resistance QTLs, and that 5 were rich in NB-ARC domain-containing disease resistance genes. The cotton genome contains numerous RGA genes, and nearly half of them are located in clusters, which evolved by sequence exchanges, tandem duplications and segmental duplications. In the Rgrcs, 26 loci were induced by the V. dahliae inoculation, and 12 are in the vicinity of known Verticillium wilt resistance QTLs.

  3. Lignin metabolism has a central role in the resistance of cotton to the wilt fungus Verticillium dahliae as revealed by RNA-Seq-dependent transcriptional analysis and histochemistry

    National Research Council Canada - National Science Library

    Li Xu; Longfu Zhu; Lili Tu; Linlin Liu; Daojun Yuan; Li Jin; Lu Long; Xianlong Zhang

    2011-01-01

    The incompatible pathosystem between resistant cotton (Gossypium barbadense cv. 7124) and Verticillium dahliae strain V991 was used to study the cotton transcriptome changes after pathogen inoculation by RNA-Seq...

  4. Effect of Verticillium dahliae soil inoculum levels on spinach seed infection

    DEFF Research Database (Denmark)

    Sapkota, Rumakanta; Olesen, Merete Halkjær; Deleuran, Lise Christina

    2016-01-01

    Verticillium dahliae is a soilborne pathogen and a threat to spinach seed production. The aim of this study was to understand the relation between V. dahliae soil inoculum and infection in harvested seed. Quantitative polymerase chain reaction was used for quantification of the pathogen. Semifield...... experiments in which spinach was grown in soils with different inoculum levels enabled us to determine a threshold level for V. dahliae DNA of 0.003 ng/g of soil for seed infection to occur. Soils from production fields were sampled in 2013 and 2014 during and before planting, as well as the harvested seed....... Seed from plants grown in infested soils were infected with V. dahliae in samples from both the semifield and open-field experiments. Lower levels of pathogen were found in seed from spinach grown in soils with a scattered distribution of V. dahliae (one or two positive of three soil subsamples) than...

  5. Verticillium Ave1 effector induces tomato defense gene expression independent of Ve1 protein.

    Science.gov (United States)

    Castroverde, Christian Danve M; Nazar, Ross N; Robb, Jane

    2016-11-01

    Verticillium resistance is thought to be mediated by Ve1 protein, which presumably follows a "gene-for-gene" relationship with the V. dahliae Ave1 effector. Because in planta analyses of Ave1 have relied so far on transient expression of the gene in tobacco, this study investigated gene function using stably expressing 35S:Ave1 transgenic tomato. Transgenic Ave1 expression was shown to induce various defense genes including those coding for PR-1 (P6), PR-2 (βbeta-1,3-glucanase) and peroxidases (anionic peroxidase 2, Cevi16 peroxidase). Since a Ve1(-) tomato cultivar served as germplasm, these results indicate that Ave1 induces these defense genes independently of Ve1.

  6. Comparative transcriptional analysis of hop responses to infection with Verticillium nonalfalfae.

    Science.gov (United States)

    Progar, Vasja; Jakše, Jernej; Štajner, Nataša; Radišek, Sebastjan; Javornik, Branka; Berne, Sabina

    2017-10-01

    Dynamic transcriptome profiling revealed excessive, yet ineffective, immune response to V. nonalfalfae infection in susceptible hop, global gene downregulation in shoots of resistant hop and only a few infection-associated genes in roots. Hop (Humulus lupulus L.) production is hampered by Verticillium wilt, a disease predominantly caused by the soil-borne fungus Verticillium nonalfalfae. Only a few hop cultivars exhibit resistance towards it and mechanisms of this resistance have not been discovered. In this study, we compared global transcriptional responses in roots and shoots of resistant and susceptible hop plants infected by a lethal strain of V. nonalfalfae. Time-series differential gene expression profiles between infected and mock inoculated plants were determined and subjected to network-based analysis of functional enrichment. In the resistant hop cultivar, a remarkably low number of genes were differentially expressed in roots in response to V. nonalfalfae infection, while the majority of differentially expressed genes were down-regulated in shoots. The most significantly affected genes were related to cutin biosynthesis, cell wall biogenesis, lateral root development and terpenoid biosynthesis. On the other hand, susceptible hop exhibited a strong defence response in shoots and roots, including increased expression of genes associated with plant responses, such as innate immunity, wounding, jasmonic acid pathway and chitinase activity. Strong induction of defence-associated genes in susceptible hop and a low number of infection-responsive genes in the roots of resistant hop are consistent with previous findings, confirming the pattern of excessive response of the susceptible cultivar, which ultimately fails to protect the plant from V. nonalfalfae. This research offers a multifaceted overview of transcriptional responses of susceptible and resistant hop cultivars to V. nonalfalfae infection and represents a valuable resource in the study of this plant

  7. Genetic Diversity of Verticillium dahliae Isolates from Olive Trees in Algeria

    Directory of Open Access Journals (Sweden)

    M. Bellahcene

    2005-12-01

    Full Text Available Verticillium wilt of olive trees (Olea europaea L., a wilt caused by the soil-borne fungus Verticillium dahliae (Kleb, is one of the most serious diseases in Algerian olive groves. To assess the pathogenic and genetic diversity of olive-infecting V. dahliae populations in Algeria, orchards from the two main olive-producing regions (north-western Algeria and Kabylia were sampled and 27 V. dahliae isolates were recovered. For purposes of comparison, V. dahliae strains from France and Syria were added to the analysis. By means of PCR primers that specifically discriminate between defoliating (D and non-defoliating (ND V. dahliae pathotypes it was shown that all V. dahliae isolates belonged to the ND pathotype. The amount of genetic variation between the 43 isolates was assessed by random amplification of polymorphic DNA (RAPD. A total of 16 RAPD haplotypes were found on the basis of the presence or absence of 25 polymorphic DNA fragments. Genotypic diversity between the 27 Algerian isolates was low, with two RAPD haplotypes accounting for 70% of all isolates. Genotypic diversity was however greater between isolates from Kabylia than between isolates from north-western Algeria. Cluster analysis showed that most of the Algerian V. dahliae isolates grouped together with the French and Syrian isolates. On the basis of their ability to form heterokaryons with each other, a subset of 25 olive-pathogenic isolates was grouped into a single vegetative compatibility group (VCG. These results suggest that the olive-infecting V. dahliae populations in Algeria show limited diversity and that caution should be taken to prevent introduction of the D pathotype.

  8. Whole genome wide expression profiles on germination of Verticillium dahliae microsclerotia.

    Directory of Open Access Journals (Sweden)

    Dongfang Hu

    Full Text Available Verticillium dahliae is a fungal pathogen causing Verticillium wilt on a range of economically important crops. Microsclerotia are its main survival and dormancy structures and serve as the primary inoculum on many hosts. Studies were conducted to determine the effect of temperature (5 to 50°C, pH (2 to 12 and nutrient regimes on microsclerotia germination. The optimal condition for microsclerotium germination was 20°C with pH 8.0 whereas nutrient regimes had no significant effect on its germination. The whole genome wide expression profiles during microsclerotium germination were characterized using the Illumina sequencing technology. Approximately 7.4 million of 21-nt cDNA tags were sequenced in the cDNA libraries derived from germinated and non-germinated microsclerotia. About 3.9% and 2.3% of the unique tags were up-regulated and down-regulated at least five-fold, respectively, in the germinated microsclerotia compared with the non-germinated microsclerotia. A total of 1654 genes showing differential expression were identified. Genes that are likely to have played important roles in microsclerotium germination include those encoding G-protein coupled receptor, lipase/esterase, cyclopentanone 1,2-monooxygenase, H(+/hexose cotransporter 1, fungal Zn(2-Cys(6 binuclear cluster domain, thymus-specific serine protease, glucan 1,3-beta-glucosidase, and alcohol dehydrogenase. These genes were mainly up-regulated or down-regulated only in germinated microsclerotia, compared with non-germinated microsclerotia. The differential expression of genes was confirmed by qRT-PCR analysis of 20 randomly selected genes from the 40 most differentially expressed genes.

  9. Expression of Baculovirus Anti-Apoptotic Genes p35 and op-iap in Cotton (Gossypium hirsutum L.) Enhances Tolerance to Verticillium Wilt

    Science.gov (United States)

    Liang, Benguo; Li, Shanwei; Wu, Zhixia; Wang, Qianhua; Leng, Chunxu; Dong, Jiangli; Wang, Tao

    2010-01-01

    Background Programmed cell death plays an important role in mediating plant adaptive responses to the environment such as the invasion of pathogens. Verticillium wilt, caused by the necrotrophic pathogen Verticillium dahliae, is a serious vascular disease responsible for great economic losses to cotton, but the molecular mechanisms of verticillium disease and effective, safe methods of resistance to verticillium wilt remain unexplored. Methodology/Principal Findings In this study, we introduced baculovirus apoptosis inhibitor genes p35 and op-iap into the genome of cotton via Agrobacterium-mediated transformation and analyzed the response of transgenic plants to verticillium wilt. Results showed that p35 and op-iap constructs were stably integrated into the cotton genome, expressed in the transgenic lines, and inherited through the T3 generation. The transgenic lines had significantly increased tolerance to verticillium wilt throughout the developmental stages. The disease index of T1–T3 generation was lower than 19, significantly (P<0.05) better than the negative control line z99668. After treatment with 250 mg/L VD-toxins for 36 hours, DNA from negative control leaves was fragmented, whereas fragmentation in the transgenic leaf DNA did not occur. The percentage of cell death in transgenic lines increased by 7.11% after 60 mg/L VD-toxin treatment, which was less than that of the negative control lines's 21.27%. This indicates that p35 and op-iap gene expression partially protects cells from VD-toxin induced programmed cell death (PCD). Conclusion/Significance Verticillium dahliae can trigger plant cells to die through induction of a PCD mechanism involved in pathogenesis. This paper provides a potential strategy for engineering broad-spectrum necrotrophic disease resistance in plants. PMID:21151969

  10. MADS-Box Transcription Factor VdMcm1 Regulates Conidiation, Microsclerotia Formation, Pathogenicity, and Secondary Metabolism of Verticillium dahliae

    OpenAIRE

    Xiong, Dianguang; Wang, Yonglin; Tian, Longyan; Tian, Chengming

    2016-01-01

    Verticillium dahliae, a notorious phytopathogenic fungus, causes vascular wilt diseases in many plant species resulting in devastating yield losses worldwide. Due to its ability to colonize plant xylem and form microsclerotia, V. dahliae is highly persistent and difficult to control. In this study, we show that the MADS-box transcription factor VdMcm1 is a key regulator of conidiation, microsclerotia formation, virulence, and secondary metabolism of V. dahliae. In addition, our findings sugge...

  11. Field resistance to Fusarium oxysporum and Verticillium dahliae in transgenic cotton expressing the plant defensin NaD1

    OpenAIRE

    Gaspar, Yolanda M.; McKenna, James A.; McGinness, Bruce S.; Hinch, Jillian; Poon, Simon; Connelly, Angela A.; Anderson, Marilyn A.; Heath, Robyn L.

    2014-01-01

    The plant defensin NaD1, from Nicotiana alata, has potent antifungal activity against a range of filamentous fungi including the two important cotton pathogens, Fusarium oxysporum f. sp. vasinfectum (Fov) and Verticillium dahliae. Transgenic cotton plants expressing NaD1 were produced and plants from three events were selected for further characterization. Homozygous plants were assessed in greenhouse bioassays for resistance to Fov. One line (D1) was selected for field trial testing over thr...

  12. Characterization of a novel single-stranded RNA mycovirus related to invertebrate viruses from the plant pathogen Verticillium dahliae.

    Science.gov (United States)

    Cañizares, M Carmen; López-Escudero, Francisco J; Pérez-Artés, Encarnación; García-Pedrajas, María D

    2017-11-16

    Fungal viruses, also known as mycoviruses, are widespread in all major groups of fungi. Mycoviruses from plant pathogens can reduce the virulence of their host fungus and have therefore potential as biological control agents. This has spurred the identification of novel mycoviruses in plant pathogens, research which is greatly contributing to our understanding of these organisms. In this work, we report the characterization of a novel monopartite mycovirus from Verticillium dahliae, the main causal agent of Verticillium wilt. This novel mycovirus, which we termed Verticillium dahliae RNA virus 1 (VdRV1), was identified in three different isolates of V. dahliae collected in olive growing areas of the Guadalquivir valley, southern Spain. We determined that the VdRV1 genome is a positive (+) single-stranded (ss) RNA, 2631 nucleotides in length, containing two open reading frames. VdRV1 showed few similarities with known mycoviruses, only with a group of unassigned (+) ssRNA mycoviruses which are related to plant viruses classified within the family Tombusviridae. However, phylogenetic analysis revealed that VdRV1 and the unassigned (+) ssRNA mycoviruses have a closer relationship with recently reported invertebrate viruses. This result indicates that as more viral sequences become available, the relationships of mycoviruses with viruses from other hosts should be reexamined. Additionally, the work supports the hypothesis of a heterogeneous origin for mycoviruses.

  13. Cotton gene expression profiles in resistant Gossypium hirsutum cv. Zhongzhimian KV1 responding to Verticillium dahliae strain V991 infection.

    Science.gov (United States)

    Zhang, Wen-Wei; Jian, Gui-Liang; Jiang, Teng-Fei; Wang, Sheng-Zheng; Qi, Fang-Jun; Xu, Shi-Chang

    2012-10-01

    Verticillium wilt of cotton (Gossypium hirsutum) is a widespread and destructive disease that is caused by the soil-borne fungus pathogen Verticillium dahliae (V. dahliae). To study the molecular mechanism in wilt tolerance, suppression subtractive hybridization (SSH) and dot blot techniques were used to identify the specifically expressed genes in a superior wilt-resistant cotton cultivar (G. hirsutum cv. Zhongzhimian KV1) after inoculation with pathogen. cDNAs from the root tissues of Zhongzhimian KV1 inoculated with V. dahliae strain V991 or water mock were used to construct the libraries that contain 4800 clones. Based on the results from dot blot analysis, 147 clones were clearly induced by V. dahliae and selected from the SSH libraries for sequencing. A total of 92 up-regulated and 7 down-regulated non-redundant expressed sequences tags (ESTs) were identified as disease responsive genes and classified into 9 functional groups. Two important clues regarding wilt-resistant G. hirsutum were obtained from this study. One was Bet v 1 family; the other was UbI gene family that may play an important role in the defense reaction against Verticillium wilt. The result from real-time quantitative reverse transcription polymerase chain reaction showed that these genes were activated quickly and transiently after inoculation with V. dahliae.

  14. Genetic structure, linkage disequilibrium and association mapping of Verticillium wilt resistance in elite cotton (Gossypium hirsutum L.) germplasm population.

    Science.gov (United States)

    Zhao, Yunlei; Wang, Hongmei; Chen, Wei; Li, Yunhai

    2014-01-01

    Understanding the population structure and linkage disequilibrium in an association panel can effectively avoid spurious associations and improve the accuracy in association mapping. In this study, one hundred and fifty eight elite cotton (Gossypium hirsutum L.) germplasm from all over the world, which were genotyped with 212 whole genome-wide marker loci and phenotyped with an disease nursery and greenhouse screening method, were assayed for population structure, linkage disequilibrium, and association mapping of Verticillium wilt resistance. A total of 480 alleles ranging from 2 to 4 per locus were identified from all collections. Model-based analysis identified two groups (G1 and G2) and seven subgroups (G1a-c, G2a-d), and differentiation analysis showed that subgroup having a single origin or pedigree was apt to differentiate with those having a mixed origin. Only 8.12% linked marker pairs showed significant LD (Presistance were identified through association mapping, which widely were distributed among 15 chromosomes. Among which 10 marker loci were found to be consistent with previously identified QTLs and 32 were new unreported marker loci, and QTL clusters for Verticillium wilt resistanc on Chr.16 were also proved in our study, which was consistent with the strong linkage in this chromosome. Our results would contribute to association mapping and supply the marker candidates for marker-assisted selection of Verticillium wilt resistance in cotton.

  15. The Verticillium dahliae SnodProt1-Like Protein VdCP1 Contributes to Virulence and Triggers the Plant Immune System

    Directory of Open Access Journals (Sweden)

    Yi Zhang

    2017-10-01

    Full Text Available During pathogenic infection, hundreds of proteins that play vital roles in the Verticillium dahliae-host interaction are secreted. In this study, an integrated proteomic analysis of secreted V. dahliae proteins was performed, and a conserved secretory protein, designated VdCP1, was identified as a member of the SnodProt1 phytotoxin family. An expression analysis of the vdcp1 gene revealed that the transcript is present in every condition studied and displays elevated expression throughout the infection process. To investigate the natural role of VdCP1 in V. dahliae, two vdcp1 knockout mutants and their complementation strains were generated. Bioassays of these mutants revealed no obvious phenotypic differences from the wild-type (WT in terms of mycelial growth, conidial production or mycelial/spore morphology. However, compared with the WT, the vdcp1 knockout mutants displayed attenuated pathogenicity in cotton plants. Furthermore, treating plants with purified recombinant VdCP1 protein expressed in Pichia pastoris induced the accumulation of reactive oxygen species (ROS, expression of several defense-related genes, leakage of ion electrolytes, enhancement of defense-related enzyme activity and production of salicylic acid. Moreover, VdCP1 conferred resistance to Botrytis cinerea and Pseudomonas syringae pv. tabaci in tobacco and to V. dahliae in cotton. Further research revealed that VdCP1 possesses chitin-binding properties and that the growth of vdcp1 knockout mutants was more affected by treatments with chitinase, indicating that VdCP1 could protect V. dahliae cell wall from enzymatic degradation, which suggests an effector role of VdCP1 in infecting hosts.

  16. Transposable elements in phytopathogenic Verticillium spp.: insights into genome evolution and inter- and intra-specific diversification

    Directory of Open Access Journals (Sweden)

    Amyotte Stefan G

    2012-07-01

    Full Text Available Abstract Background Verticillium dahliae (Vd and Verticillium albo-atrum (Va are cosmopolitan soil fungi causing very disruptive vascular diseases on a wide range of crop plants. To date, no sexual stage has been identified in either microorganism suggesting that somatic mutation is a major force in generating genetic diversity. Whole genome comparative analysis of the recently sequenced strains VdLs.17 and VaMs.102 revealed that non-random insertions of transposable elements (TEs have contributed to the generation of four lineage-specific (LS regions in VdLs.17. Results We present here a detailed analysis of Class I retrotransposons and Class II “cut-and-paste” DNA elements detected in the sequenced Verticillium genomes. We report also of their distribution in other Vd and Va isolates from various geographic origins. In VdLs.17, we identified and characterized 56 complete retrotransposons of the Gypsy-, Copia- and LINE-like types, as well as 34 full-length elements of the “cut-and-paste” superfamilies Tc1/mariner, Activator and Mutator. While Copia and Tc1/mariner were present in multiple identical copies, Activator and Mutator sequences were highly divergent. Most elements comprised complete ORFs, had matching ESTs and showed active transcription in response to stress treatment. Noticeably, we found evidences of repeat-induced point mutation (RIP only in some of the Gypsy retroelements. While Copia-, Gypsy- and Tc1/mariner-like transposons were prominent, a large variation in presence of the other types of mobile elements was detected in the other Verticillium spp. strains surveyed. In particular, neither complete nor defective “cut-and-paste” TEs were found in VaMs.102. Conclusions Copia-, Gypsy- and Tc1/mariner-like transposons are the most wide-spread TEs in the phytopathogens V. dahliae and V. albo-atrum. In VdLs.17, we identified several retroelements and “cut-and-paste” transposons still potentially active. Some of these

  17. Biochemical indices of hop resistance to Verticillium albo-atrum and Fusarium sambucinum

    Directory of Open Access Journals (Sweden)

    Jan Piotrowski

    2013-12-01

    Full Text Available The contents of total phenolic compounds, chlorogenic acid and peroxidase activity as well as monophenols to polyphenols ratio were studies in the suckers of the hops as indices of resistance to Verticillium albo-atrum and Fusarium sambucinum. The suckers of hop taken in the early spring from the healthy and infected plots were used in the experiments. As a research material were included cv. 'Northern Brewer' - a wilt tolerant variety, two wild susceptible varieties - cv. 'Lubelski' and cv. 'Brewers Gold', four breeding clones and one male plant. It was found that, 'Northern Brewer' contains more total phenolic compounds, rnonophenols and chlorogenic acid, and in particular considerably higher peroxidase activity as compared to cv. 'Lubelski'. Taking into consideration the contents of these compounds, in the majority of cases, the new breeding clones were similar to the mother variety 'Northern Brewer'. It seems resonable to assume, that the new clones should be more wilt tolerant than varieties and populations cultivated in our country.

  18. Properties of a hydrophobin isolated from the mycoparasitic fungus Verticillium fungicola.

    Science.gov (United States)

    Calonje, Myriam; Bernardo, Dolores; Novaes-Ledieu, Monique; García Mendoza, Concepción

    2002-11-01

    Verticillium fungicola, isolated from Agaricus bisporus (commercial mushroom), produced significant extracellular hydrophobin when grown for 7 days in a static liquid culture of synthetic minimal medium. The hydrophobin was purified by precipitation with ammonium sulphate (80% saturation), Sephadex G-100 gel filtration, and hydroxyapatite column chromatography. The purified protein yielded a single band in polyacrylamide gel electrophoresis under native conditions, with an apparent molecular mass of 70 +/- 4 kDa, and also another single band in SDS-PAGE, with a molecular mass of 7 +/- 3 kDa. Molecular mass determined with matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) resulted in 7563.9 m/z. The same protein was extracted from the V. fungicola mycelium. Analysis of the amino acid composition revealed the presence of about 50% hydrophobic residues, detecting at least six cysteines, evaluated as cystines, and no free sulfhydryl groups. The protein did not show any glycosylation. On the basis of similarities in hydropathy patterns and solubility characteristics, V. fungicola hydrophobin can be included as a new member of Class II hydrophobins.

  19. Effect of the fungicide Prochloraz-Mn on the cell wall structure of Verticillium fungicola.

    Science.gov (United States)

    Bernardo, D; Novaes-Ledieu, M; Perez Cabo, A; Gea Alegría, F J; García Mendoza, C

    2002-09-01

    The chemical structure of the cell wall of two isolates of Verticillium fungicolacollected from diseased fruit bodies of the commercial mushroom Agaricus bisporus treated with the fungicide Prochloraz-Mn was analyzed. The isolates were obtained during different periods of time and grown in the absence and presence of the LD(50) values of the fungicide for V. fungicola. In addition, another V. fungicola isolate collected previous to the routine utilization of Prochloraz-Mn but grown under the same conditions was also analyzed. The overall chemical composition of the cell wall from the three isolates showed detectable differences in their basic components, with a significant decrease in the protein content in fungicide-treated cells. This inhibitory effect was partially compensated by an increase in neutral and/or aminated carbohydrates and was accompanied by appreciable modifications of polysaccharide structure, as deduced after methylation analysis and gas-liquid chromatography-mass spectrometry (GLC-MS). Moreover, differences in hyphal morphology caused by the fungicide were observed by transmission electron microscopy (TEM).

  20. Biological Control of Sclerotium rolfsii and Verticillium dahliae by Talaromyces flavus Is Mediated by Different Mechanisms.

    Science.gov (United States)

    Madi, L; Katan, T; Katan, J; Henis, Y

    1997-10-01

    ABSTRACT Ten wild-type strains and two benomyl-resistant mutants of Talaromyces flavus were examined for their ability to secrete the cell wall-degrading enzymes chitinase, beta-1,3-glucanase, and cellulase, to parasitize sclerotia of Sclerotium rolfsii, to reduce bean stem rot caused by S. rolfsii, and to secrete antifungal substance(s) active against Verticillium dahliae. The benomyl-resistant mutant Ben(R)TF1-R6 overproduced extracellular enzymes and exhibited enhanced antagonistic activity against S. rolfsii and V. dahliae compared to the wild-type strains and other mu tants. Correlation analyses between the extracellular enzymatic activities of different isolates of T. flavus and their ability to antagonize S. rolfsii indicated that mycoparasitism by T. flavus and biological control of S rolfsii were related to the chitinase activity of T. flavus. On the other hand, production of antifungal compounds and glucose-oxidase activity may play a role in antagonism of V. dahliae by retardation of germination and hyphal growth and melanization of newly formed microsclerotia.

  1. Isolation and characterization of putative endophytic bacteria antagonistic to Phoma tracheiphila and Verticillium albo-atrum.

    Science.gov (United States)

    Kalai-Grami, Leila; Saidi, Sabrine; Bachkouel, Sarra; Ben Slimene, Imen; Mnari-Hattab, Monia; Hajlaoui, Mohamed Rebah; Limam, Ferid

    2014-09-01

    A collection of 200 bacterial isolates recovered from citrus plants (Citrus limon, Citrus sinensis, and Citrus reticulata), Medicago truncatula and Laurus nobilis, was established. In vitro screening indicated that 28 isolates exhibited an inhibitory activity against the vascular pathogens Phoma tracheiphila and Verticillium albo-atrum. Isolates were screened according to their hydrolytic activities, plant growth-promoting bacteria (PGPB) abilities, as well as for the presence of nonribosomal peptide synthetase (NRPS) genes responsible of the lipopeptide biosynthesis. The results were positive for 16 isolates which exhibited at least two PGPB activities and a single NRPS gene. Genetic diversity of the selected isolates was studied using random amplified polymorphic DNA (RAPD) and repetitive element PCR (REP) tools that showed clustering of strains into three major groups (I, II, and III) (i, ii, and iii), respectively. Clustering was further confirmed by the 16S rDNA sequencing that assigned nine isolates to Bacillus velezensis, four isolates to Bacillus methyltrophicus, one isolate to Bacillus amyloliquefaciens, and two isolates to Bacillus mojavensis. Organ-bacterial genotype interaction as well as positive correlation with NRPS genes are discussed.

  2. Vayg1 is required for microsclerotium formation and melanin production in Verticillium dahliae.

    Science.gov (United States)

    Fan, Rong; Klosterman, Steven J; Wang, Conghao; Subbarao, Krishna V; Xu, Xiangming; Shang, Wenjing; Hu, Xiaoping

    2017-01-01

    The fungus Verticillium dahliae causes vascular wilt disease on many plant species, including economically important crop and ornamental plants worldwide. It produces darkly pigmented resting structures known as microsclerotia, which are able to survive for up to 14years in soil, and represent one of the defining characteristics of this species. The pigment produced in V. dahliae is dihydroxynaphthalene (DHN)-melanin, a form of melanin common among fungi and named so for the intermediary of this melanin biosynthetic pathway. In this study, we characterized the function of the V. dahliae Vayg1 gene, whose homologs were involved in melanin biosynthesis in Exophiala dermatitidis (Wayg1) and Aspergillus fumigatus (Aayg1), by deletion and complementation of the gene and co-incubating deletion mutant with wild-type strain. Results showed that melanin production and microsclerotial formation in deletion mutants are inhibited. The Vayg1 deletion mutant also exhibited reduced pathogenicity. These results showed that Vayg1 is necessary for melanin and microsclerotium production, and we may thus hypothesize that the Vayg1 product may catalyze two different precursors, one of which is essential for DHN melanin production and the other one is involved in a signal network for microsclerotial formation in V. dahliae. Copyright © 2016 Elsevier Inc. All rights reserved.

  3. Verticillium wilt of olive branches in Iran and its control managements with soil solarization method.

    Science.gov (United States)

    Saremi, H; Amarlou, A; Okhovvat, S M

    2006-01-01

    Wilting of mostly one branch in nurseries and newly established orchards of olive was studied in eastern north of Iran including Zanjan, Golestan and Khorassan provinces during 2002-2004. Different infected plants were visited and samples showing symptoms including wilting or death of branches collected from various areas and transferred to laboratory. Samples were cultured in common media (PDA) and different fungi were identified. The most frequently isolated pathogen was Verticillium dahliae which caused wilting of mostly one branch of olive seedling or trees in studied areas. Results showed that the disease caused main losses where olive cuttings were cultured in infected soils, previously cropped to susceptible plants. In fact, the population density of V. dahliae was high in the garden soil, previously produced susceptible crop cultivar to the fungus especially cotton or potatoes. Soil disinfestations by soil solarization method was carried in Taroam as the warmer climate in studied areas to control the pathogen. Application of this method reduced population density of the pathogen from 1700 CFU g/soil to 1000 after 4 weeks. This method was simple, effective, non negative side and economic which can be used in nearly warm areas.

  4. [Construction and analysis of SSH library of Gossypium barbadense upon infection with Verticillium dahliae].

    Science.gov (United States)

    Zhu, Long-Fu; Tu, Li-Li; Zhang, Xian-Long; Nie, Yi-Chun; Guo, Xiao-Ping; Xia, Qi-Zhong

    2005-05-01

    Roots were collected from the seedlings inoculated with pathogen Verticillium dahliae after 2, 4, 8, 12, 24, 48, 72 and 96 hours for total RNA extraction. The cDNAs from the inoculated seedlings were used as the tester and those from the control seedlings as the driver. SSH method was employed to find the differently expressed cDNAs responding to the pathogen. T/A clone library was constructed containing 534 clones. The cDNA inserts were amplified from the bacterial clones directly with M13 primers by PCR. The size of the products ranged 0.2 - 1.2 kb with an average size of 0.5 kb. The SSH products were dotted on nylon filters, and the positive clones were screened by virtual Northern blotting with probes of the two kinds of initiative cDNAs. Totally 78 clones which were up-regulated and putatively involved in the defense response of G. barbadense were identified and sequenced. Sequence similarity searches were performed with the Blastn and Blastx. Most of them showed high or partial homology to genes or ESTs induced by different stresses in Arabidopsis thaliana and other species,such as the pathogenesis-related 10 family of G. hirsumtum and disease resistance-responsive family protein in Arabidopsis thaliana. The results would be helpful to understand the molecular mechanisms of disease response in cotton.

  5. The beneficial fungus Piriformospora indica protects Arabidopsis from Verticillium dahliae infection by downregulation plant defense responses.

    Science.gov (United States)

    Sun, Chao; Shao, Yongqi; Vahabi, Khabat; Lu, Jing; Bhattacharya, Samik; Dong, Sheqin; Yeh, Kai-Wun; Sherameti, Irena; Lou, Binggan; Baldwin, Ian T; Oelmüller, Ralf

    2014-10-09

    Verticillium dahliae (Vd) is a soil-borne vascular pathogen which causes severe wilt symptoms in a wide range of plants. The microsclerotia produced by the pathogen survive in soil for more than 15 years. Here we demonstrate that an exudate preparation induces cytoplasmic calcium elevation in Arabidopsis roots, and the disease development requires the ethylene-activated transcription factor EIN3. Furthermore, the beneficial endophytic fungus Piriformospora indica (Pi) significantly reduced Vd-mediated disease development in Arabidopsis. Pi inhibited the growth of Vd in a dual culture on PDA agar plates and pretreatment of Arabidopsis roots with Pi protected plants from Vd infection. The Pi-pretreated plants grew better after Vd infection and the production of Vd microsclerotia was dramatically reduced, all without activating stress hormones and defense genes in the host. We conclude that Pi is an efficient biocontrol agent that protects Arabidopsis from Vd infection. Our data demonstrate that Vd growth is restricted in the presence of Pi and the additional signals from Pi must participate in the regulation of the immune response against Vd.

  6. Salicylic acid-related cotton (Gossypium arboreum) ribosomal protein GaRPL18 contributes to resistance to Verticillium dahliae.

    Science.gov (United States)

    Gong, Qian; Yang, Zhaoen; Wang, Xiaoqian; Butt, Hamama Islam; Chen, Eryong; He, Shoupu; Zhang, Chaojun; Zhang, Xueyan; Li, Fuguang

    2017-03-03

    Verticillium dahliae is a phytopathogenic fungal pathogen that causes vascular wilt diseases responsible for considerable decreases in cotton yields. The complex mechanism underlying cotton resistance to Verticillium wilt remains uncharacterized. Identifying an endogenous resistance gene may be useful for controlling this disease. We cloned the ribosomal protein L18 (GaRPL18) gene, which mediates resistance to Verticillium wilt, from a wilt-resistant cotton species (Gossypium arboreum). We then characterized the function of this gene in cotton and Arabidopsis thaliana plants. GaRPL18 encodes a 60S ribosomal protein subunit important for intracellular protein biosynthesis. However, previous studies revealed that some ribosomal proteins are also inhibitory toward oncogenesis and congenital diseases in humans and play a role in plant disease defense. Here, we observed that V. dahliae infections induce GaRPL18 expression. Furthermore, we determined that the GaRPL18 expression pattern is consistent with the disease resistance level of different cotton varieties. GaRPL18 expression is upregulated by salicylic acid (SA) treatments, suggesting the involvement of GaRPL18 in the SA signal transduction pathway. Virus-induced gene silencing technology was used to determine whether the GaRPL18 expression level influences cotton disease resistance. Wilt-resistant cotton species in which GaRPL18 was silenced became more susceptible to V. dahliae than the control plants because of a significant decrease in the abundance of immune-related molecules. We also transformed A. thaliana ecotype Columbia (Col-0) plants with GaRPL18 according to the floral dip method. The plants overexpressing GaRPL18 were more resistant to V. dahliae infections than the wild-type Col-0 plants. The enhanced resistance of transgenic A. thaliana plants to V. dahliae is likely mediated by the SA pathway. Our findings provide new insights into the role of GaRPL18, indicating that it plays a crucial role in

  7. Onderstammen voor de biologische teelt van vruchtgroenten : inventarisatie van resistente onderstammen van komkommer en paprika voor Meiloidogyne spp. en Verticillium dahliae

    NARCIS (Netherlands)

    Labrie, C.W.

    2008-01-01

    A literature study has been carried out about resistance and tolerance of cucumber and sweet pepper rootstocks to Meloidogyne spp. and Verticillium dahliae. This study offers an overview of research in practice and international scientific literature. For cucumber no rootstocks are known that are

  8. Inheritance and variability of tolerance to Verticillium dahliae Kleb amoung geographically remote F1-F2 hybrids of Gossypium hirsutum L.

    Science.gov (United States)

    One of the most important problems for cotton breeding in Uzbekistan is development of Verticillium dahliae tolerant varieties. One approach is to utilize ecologically remote intraspecific and interspecific hybridization with local commercial cultivars. To this end, we have conducted genetically b...

  9. Morphology of Verticillium dahliae and V. tricorpus on semi-selective media used for the detection of V. dahliae in soil

    NARCIS (Netherlands)

    Goud, J.C.; Termorshuizen, A.J.; Gams, W.

    2003-01-01

    The morphology of two soil-borne Verticillium species, V. dahliae and V. tricorpus, was studied on two semi-selective agar media, in the absence and presence of soil. Morphology of the fungi differed considerably between the media, with respect to presence and shape of microsclerotia, dark hyphae

  10. Long-term effects of eight soil health treatments to control plant-parasitic nematodes and Verticillium dahliae in agro-ecosystems

    NARCIS (Netherlands)

    Korthals, G.W.; Thoden, T.C.; Berg, van den W.; Visser, J.H.M.

    2014-01-01

    There is an urgent need to test and develop sustainable methods for management of soil pathogens, such as the root-lesion nematode Pratylenchus penetrans and the soil fungus Verticillium dahliae. Ultimately this should be investigated with a multidisciplinary approach, with long-term measurements of

  11. Identification of pathogenicity-related genes in the vascular wilt fungus verticillium dahliae by agrobacterium tumefaciens-mediated t-DNA insertional mutagenesis.

    Science.gov (United States)

    Verticillium dahliae is the causal agent of vascular wilt in many economically important crops worldwide. Identification of genes that underpin pathogenicity or virulence may suggest targets for alternative control methods for this fungus. In this study, Agrobacterium tumefaciens-mediated transform...

  12. Characterization of a Novel Cotton Subtilase Gene GbSBT1 in Response to Extracellular Stimulations and Its Role in Verticillium Resistance.

    Science.gov (United States)

    Duan, Xingpeng; Zhang, Zhidong; Wang, Jin; Zuo, Kaijing

    2016-01-01

    Verticillium wilt is a disastrous vascular disease in plants caused by Verticillium dahliae. Verticillium pathogens secrete various disease-causing effectors in cotton. This study identified a subtilase gene GbSBT1 from Gossypium babardense and investigated the roles against V. dahliae infection. GbSBT1 gene expression is responsive to V. dahliae defense signals, jasmonic acid, and ethylene treatments. Moreover, the GbSBT1 protein is mainly localized in the cell membrane and moves into the cytoplasm following jasmonic acid and ethylene treatments. Silencing GbSBT1 gene expression through virus-induced GbSBT1 gene silencing reduced the tolerance of Pima-90 (resistant genotype), but not facilitated the infection process of V. dahliae in Coker-312 (sensitive genotype). Moreover, the ectopically expressed GbSBT1 gene enhanced the resistance of Arabidopsis to Fusarium oxysporum and V. dahliae infection and activated the expression levels of defense-related genes. Furthermore, pull-down, yeast two-hybrid assay, and BiFC analysis revealed that GbSBT1 interacts with a prohibitin (PHB)-like protein expressed in V. dahliae pathogens during infection. In summary, GbSBT1 recognizes the effector PHB protein secreted from V. dahliae and is involved in Verticillium-induced resistance in cotton.

  13. Late summer disease symptoms in western Washington red raspberry fields associated with co-occurrence of Phytophthora rubi, Verticillium dahliae, and Pratylenchus penetrans

    Science.gov (United States)

    60% of the $109 million processed by the U.S. red raspberry industry is in northern Washington. In 2012, late summer disease symptoms were observed in many raspberry fields. These symptoms were initially attributed to Verticillium dahliae, but other soilborne pathogens (Phytophthora rubi, Pratylench...

  14. Genotyping-by-sequencing based genome-wide association studies on Verticillium wilt resistance in heterozygous autotetraploid alfalfa (Medicago sativa L.)

    Science.gov (United States)

    Verticillium wilt (VW) is a fungal disease which causes severe yield loss in alfalfa. The most effective method to control the disease is through the development and use of resistant varieties. Identification of gene loci linked to VW resistance will facilitate breeding for the disease-resistant al...

  15. Transcriptome profiling of Gossypium barbadense inoculated with Verticillium dahliae provides a resource for cotton improvement.

    Science.gov (United States)

    Zhang, Yan; Wang, Xing Fen; Ding, Ze Guo; Ma, Qing; Zhang, Gui Rong; Zhang, Shu Ling; Li, Zhi Kun; Wu, Li Qiang; Zhang, Gui Yin; Ma, Zhi Ying

    2013-09-22

    Verticillium wilt, caused by the fungal pathogen Verticillium dahliae, is the most severe disease in cotton (Gossypium spp.), causing great lint losses worldwide. Disease management could be achieved in the field if genetically improved, resistant plants were used. However, the interaction between V. dahliae and cotton is a complicated process, and its molecular mechanism remains obscure. To understand better the defense response to this pathogen as a means for obtaining more tolerant cultivars, we monitored the transcriptome profiles of roots from resistant plants of G. barbadense cv. Pima90-53 that were challenged with V. dahliae. In all, 46,192 high-quality expressed sequence tags (ESTs) were generated from a full-length cDNA library of G. barbadense. They were clustered and assembled into 23126 unigenes that comprised 2661 contigs and 20465 singletons. Those unigenes were assigned Gene Ontology terms and mapped to 289 KEGG pathways. A total of 3027 unigenes were found to be homologous to known defense-related genes in other plants. They were assigned to the functional classification of plant-pathogen interactions, including disease defenses and signal transduction. The branch of "SA→NPR1→TGA→PR-1→Disease resistance" was first discovered in the interaction of cotton-V. dahliae, indicating that this wilt process includes both biotrophic and necrotrophic stages. In all, 4936 genes coding for putative transcription factors (TF) were identified in our library. The most abundant TF family was the NAC group (527), followed by G2-like (440), MYB (372), BHLH (331), bZIP (271) ERF, C3H, and WRKY. We also analyzed the expression of genes involved in pathogen-associated molecular pattern (PAMP) recognition, the activation of effector-triggered immunity, TFs, and hormone biosynthesis, as well as genes that are pathogenesis-related, or have roles in signaling/regulatory functions and cell wall modification. Their differential expression patterns were compared among

  16. Spatial Pattern of Verticillium dahliae Microsclerotia and Cotton Plants with Wilt Symptoms in Commercial Plantations.

    Directory of Open Access Journals (Sweden)

    Feng Wei

    Full Text Available Spatial patterns of pathogen inoculum in field soils and the resulting patterns of disease may reflect the underlying mechanisms of pathogen dispersal. This knowledge can be used to design more efficient sampling schemes for assessing diseases. Spatial patterns of Verticillium dahliae microsclerotia were characterized in commercial cotton fields through quadrat and point sampling in 1994 and 2013, respectively. Furthermore, cotton plants with wilt symptoms, caused by V. dahliae, were assessed in six commercial cotton fields in 2013. Soil samples were assayed for the density of microsclerotia (expressed as CFU g-1 of soil using a wet-sieving plating method and a real-time quantitative PCR method for the 1994 and 2013 study, respectively. The estimated inoculum threshold for causing wilt development on individual plants varied with the three fields: ca. 1.6 CFU g-1 of soil for one field, and 7.2 CFU g-1 of soil for the other two. Both quadrat and point sampling spatial analyses showed that aggregation of V. dahliae inoculum in soils was usually not detected beyond 1.0 m. Similarly, the spatial patterns of wilted cotton plants indicated that spatial aggregation of diseased plants were only observed below the scale of 1.0 m in six commercial cotton plantations. Therefore, spatial aggregation of both V. dahliae inoculum and cotton plants with wilt symptoms is not likely to be detected above the scale of 1.0 m for most commercial cotton plantations. When designing schemes for assessing wilt inoculum and wilt development, this scale needs to be taken into consideration.

  17. A fungal protein elicitor PevD1 induces Verticillium wilt resistance in cotton.

    Science.gov (United States)

    Bu, Bingwu; Qiu, Dewen; Zeng, Hongmei; Guo, Lihua; Yuan, Jingjing; Yang, Xiufen

    2014-03-01

    We found that the elicitor PevD1 triggered innate immunity in cotton, which plays an important role in future cotton wilt disease control. Elicitors can induce defense responses in plants and improve pathogen resistance. PevD1 is a secreted protein from Verticillium dahliae and activates the hypersensitive response and systemic acquired resistance to tobacco mosaic virus in tobacco plants. To investigate the PevD1-induced disease resistance mechanisms in cotton (Gossypium hirsutum), we report that Escherichia coli expressing PevD1 enhanced cotton resistance and the defense response to the fungal pathogen V. dahliae. The results showed that recombinant PevD1 improved cotton resistance when infiltrated at a concentration as low as 4 μg ml(-1), and the highest disease reduction was 38.16 % on the 15th day post V. dahliae inoculation. This protein was able to systemically induce hydrogen peroxide production, nitric oxide generation, lignin deposition, vessel reinforcement and defense enzymes, including phenylalanine ammonia-lyase, peroxidase, and polyphenol oxidase. PevD1 also enhanced the expression of three pathogenesis-related genes, namely, β-1,3-glucanase, chitinase, and cadinene synthase, and three key genes, PAL, C4H1, and 4CL, from the cotton defense phenylpropanoid metabolism pathway. Our results demonstrated that PevD1 acted as an effector in cotton and V. dahliae interactions and triggered innate immunity in cotton, resulting in the upregulation of defense-related genes, metabolic substance deposition and cell wall modifications. PevD1 is a candidate plant defense activator for cotton wilt disease control.

  18. Transcriptomic Analysis of Olea europaea L. Roots during the Verticillium dahliae Early Infection Process

    Directory of Open Access Journals (Sweden)

    Jaime Jiménez-Ruiz

    2017-03-01

    Full Text Available Olive cultivation is affected by a wide range of biotic constraints. Verticillium wilt of olive is one of the most devastating diseases affecting this woody crop, inflicting major economic losses in many areas, particularly within the Mediterranean Basin. Little is known about gene-expression changes during plant infection by of woody plants such as olive. A complete RNA-seq transcriptomic analysis of olive tree roots was made. Trinity assembler proved to be the best option to assemble the olive and transcriptomes. The olive transcriptome (Oleup consisted of 68,259 unigenes (254,252 isoforms/transcripts, and the transcriptome (Vedah consisted of 37,425 unigenes (52,119 isoforms/transcripts. Most unigenes of the Oleup transcriptome corresponded to cellular processes (12,339, metabolic processes (10,974, single-organism processes (7263, and responses to stimuli (5114. As for the Vedah transcriptome, most unigenes correspond to metabolic processes (25,372, cellular processes (23,718, localization (6385, and biological regulation (4801. Differential gene-expression analysis of both transcriptomes was made at 2 and 7 d post-infection. The induced genes of both organisms during the plant-pathogen interaction were clustered in six subclusters, depending on the expression patterns during the infection. Subclusters A to C correspond to plant genes, and subcluster D to F correspond to genes. A relevant finding was that the differentially expressed gene (DEGs included in subclusters B and C were highly enriched in proteolysis as well as protein-folding and biosynthesis genes. In addition, a reactive oxygen species (ROS defense was induced first in the pathogen and later in the plant roots.

  19. Field resistance to Fusarium oxysporum and Verticillium dahliae in transgenic cotton expressing the plant defensin NaD1.

    Science.gov (United States)

    Gaspar, Yolanda M; McKenna, James A; McGinness, Bruce S; Hinch, Jillian; Poon, Simon; Connelly, Angela A; Anderson, Marilyn A; Heath, Robyn L

    2014-04-01

    The plant defensin NaD1, from Nicotiana alata, has potent antifungal activity against a range of filamentous fungi including the two important cotton pathogens, Fusarium oxysporum f. sp. vasinfectum (Fov) and Verticillium dahliae. Transgenic cotton plants expressing NaD1 were produced and plants from three events were selected for further characterization. Homozygous plants were assessed in greenhouse bioassays for resistance to Fov. One line (D1) was selected for field trial testing over three growing seasons in soils naturally infested with Fov and over two seasons in soils naturally infested with V. dahliae. In the field trials with Fov-infested soil, line D1 had 2-3-times the survival rate, a higher tolerance to Fov (higher disease rank), and a 2-4-fold increase in lint yield compared to the non-transgenic Coker control. When transgenic line D1 was planted in V. dahliae-infested soil, plants had a higher tolerance to Verticillium wilt and up to a 2-fold increase in lint yield compared to the non-transgenic Coker control. Line D1 did not exhibit any detrimental agronomic features compared to the parent Coker control when plants were grown in non-diseased soil. This study demonstrated that the expression of NaD1 in transgenic cotton plants can provide substantial resistance to two economically important fungal pathogens.

  20. Early Detection and Quantification of Verticillium Wilt in Olive Using Hyperspectral and Thermal Imagery over Large Areas

    Directory of Open Access Journals (Sweden)

    Rocío Calderón

    2015-05-01

    Full Text Available Automatic methods for an early detection of plant diseases (i.e., visible symptoms at early stages of disease development using remote sensing are critical for precision crop protection. Verticillium wilt (VW of olive caused by Verticillium dahliae can be controlled only if detected at early stages of development. Linear discriminant analysis (LDA and support vector machine (SVM classification methods were applied to classify V. dahliae severity using remote sensing at large scale. High-resolution thermal and hyperspectral imagery were acquired with a manned platform which flew a 3000-ha commercial olive area. LDA reached an overall accuracy of 59.0% and a κ of 0.487 while SVM obtained a higher overall accuracy, 79.2% with a similar κ, 0.495. However, LDA better classified trees at initial and low severity levels, reaching accuracies of 71.4 and 75.0%, respectively, in comparison with the 14.3% and 40.6% obtained by SVM. Normalized canopy temperature, chlorophyll fluorescence, structural, xanthophyll, chlorophyll, carotenoid and disease indices were found to be the best indicators for early and advanced stage infection by VW. These results demonstrate that the methods developed in other studies at orchard scale are valid for flights in large areas comprising several olive orchards differing in soil and crop management characteristics.

  1. Arabidopsis thaliana as a tool to identify traits involved in Verticillium dahliae biocontrol by the olive root endophyte Pseudomonas fluorescens PICF7

    Directory of Open Access Journals (Sweden)

    M. Mercedes eMaldonado-González

    2015-04-01

    Full Text Available The effective management of Verticillium wilts, diseases affecting many crops and caused by some species of the soil-borne fungus Verticillium, is problematic. The use of microbial antagonists to control these pathologies fits modern sustainable agriculture criteria. Pseudomonas fluorescens PICF7 is an endophytic bacterium isolated from olive roots with demonstrated ability to control Verticillium wilt of olive caused by the highly-virulent, defoliating (D pathotype of Verticillium dahliae Kleb. However, the study of the PICF7-V.dahliae-olive tripartite interaction poses difficulties because of the inherent characteristics of woody, long-living plants. To overcome these problems we explored the use of the model plant Arabidopsis thaliana. Results obtained in this study showed that: (i olive D and non-defoliating (ND V. dahliae pathotypes produce differential disease severity in A. thaliana plants; (ii strain PICF7 is able to colonize and persist in the A. thaliana rhizosphere but is not endophytic in Arabidopsis; and (iii strain PICF7 controls Verticillium wilt (VW in Arabidopsis. Additionally, as previously observed in olive, neither swimming motility nor siderophore production by PICF7 are required for VW control in A. thaliana, whilst cysteine auxotrophy decreased the effectiveness of PICF7. Moreover, when applied to the roots PICF7 controlled Botrytis cinerea infection in the leaves of Arabidopsis, suggesting that this strain is able to induce systemic resistance. Arabidopsis thaliana is therefore a suitable alternative to olive bioassays to unravel biocontrol traits involved in biological control of V. dahliae by P. fluorescens PICF7.

  2. Bidirectional promoter trapping T-DNA for insertional mutagenesis in Verticillium dahliae.

    Science.gov (United States)

    Deng, Sheng; Wang, Cai-yue; Zhang, Xin; Lin, Ling

    2014-07-01

    Transfer DNA (T-DNA)-based random insertional mutagenesis is a universal forward genetic approach for gene identification and cloning in many phytopathogenic fungi. In a large number of randomly selected transformants, screening for mutants with a specific phenotype is laborious, especially for pathogenicity-defective mutants. To accelerate mutant screening and gene identification, a bidirectional promoter-trapping Ti binary vector, 1300-bisGFP-hyg, was constructed and deployed in this study. More than 6000 Verticillium dahliae transformants were obtained by the mediation of Agrobacterium tumefaciens carrying the vector. One thousand randomly selected transformants were cultured on Czapek-Dox and on Czapek-Dox plus cotton root extract media plates. The cultured transformants with green fluorescent protein (GFP) expression or changes in phenotype were selected and used in virulence or promoter-trapping assays. Based on the virulence assay of 60 transformants, the pathogenicity of 17 of these mutants was compromised. Ten pathogenicity-defective mutants were found with GFP expression, and 6 with expression in Czapek-Dox plus cotton root extract media specifically. Using TAIL-PCR (thermal asymmetric interlaced polymerase chain reaction), the T-DNA insertion sites were identified in 8 GFP-expressing transformants, including 5 pathogenicity-defective mutants and 3 unaffected transformants. Promoters of 6 genes were successfully trapped using the T-DNA method in this study. The nonpathogenic transformant 24C9 was the subject of additional investigation. It displayed strong GFP expression on water agar medium supplemented with cotton root extracts and on cotton seedling stems. The results obtained by Southern blot and quantitative real-time PCR confirmed that the transcription level of VdUGPU (encoding UTP-glucose-1-phosphate uridylyltransferase) was significantly reduced owing to T-DNA insertion in the gene promoter region. These results indicate that the bidirectional

  3. Response of Verticillium fungicola var. fungicola, Mycogone perniciosa_and Cladobotrym sp. Mushroom Pathogens to Some Essential Oils

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    Brankica Tanović

    2006-01-01

    Full Text Available Antifungal activity of 18 essential oils was evaluated against Verticillium fungicola var. fungicola, Mycogone perniciosa and Cladobotryum sp., the causal agents of button mushroom diseases. Essential oils including: turpentine, basil, lemon, mint, fenchel, rose geranium, anise, cinnamon, scots pine, clove, thyme, juniper, lavender, orange, eucalyptus, rosemary, bergamot orange and tea tree, were screened for their effectiveness against the pathogens in vitro. In order to investigate fungicidal activity, isolates were exposed to the volatile phase of the oils for seven days. Of the 18 essential oils analyzed, cinnamon, clove, thyme, and tea tree showed the highest antifungal activity against all investigated mycopathogens,with Minimum Fungicidal Concentration (MFC being 0.02 μl/ml of air. Turpentine essential oil expressed the lowest antifungal effect to all isolates tested.

  4. Broad taxonomic characterization of Verticillium wilt resistance genes reveals an ancient origin of the tomato Ve1 immune receptor.

    Science.gov (United States)

    Song, Yin; Zhang, Zhao; Seidl, Michael F; Majer, Aljaz; Jakse, Jernej; Javornik, Branka; Thomma, Bart P H J

    2017-02-01

    Plant-pathogenic microbes secrete effector molecules to establish themselves on their hosts, whereas plants use immune receptors to try and intercept such effectors in order to prevent pathogen colonization. The tomato cell surface-localized receptor Ve1 confers race-specific resistance against race 1 strains of the soil-borne vascular wilt fungus Verticillium dahliae which secrete the Ave1 effector. Here, we describe the cloning and characterization of Ve1 homologues from tobacco (Nicotiana glutinosa), potato (Solanum tuberosum), wild eggplant (Solanum torvum) and hop (Humulus lupulus), and demonstrate that particular Ve1 homologues govern resistance against V. dahliae race 1 strains through the recognition of the Ave1 effector. Phylogenetic analysis shows that Ve1 homologues are widely distributed in land plants. Thus, our study suggests an ancient origin of the Ve1 immune receptor in the plant kingdom. © 2016 BSPP AND JOHN WILEY & SONS LTD.

  5. Colonization of resistant and susceptible lettuce cultivars by a green fluorescent protein-tagged isolate of Verticillium dahliae.

    Science.gov (United States)

    Vallad, G E; Subbarao, K V

    2008-08-01

    Interactions between lettuce and a green fluorescent protein (GFP)-expressing, race 1 isolate of Verticillium dahliae, were studied to determine infection and colonization of lettuce cultivars resistant and susceptible to Verticillium wilt. The roots of lettuce seedlings were inoculated with a conidial suspension of the GFP-expressing isolate. Colonization was studied with the aid of laser scanning confocal and epi-fluorescence microscopes. Few differences in the initial infection and colonization of lateral roots were observed between resistant and susceptible cultivars. Hyphal colonies formed on root tips and within the root elongation zones by 5 days, leading to the colonization of cortical tissues and penetration of vascular elements regardless of the lettuce cultivar by 2 weeks. By 8 to 10 weeks after inoculation, vascular discoloration developed within the taproot and crown regions of susceptible cultivars well in advance of V. dahliae colonization. Actual foliar wilt coincided with the colonization of the taproot and crown areas and the eruption of mycelia into surrounding cortical tissues. Advance colonization of stems, pedicels, and inflorescence, including developing capitula and mature achenes was observed. Seedborne infection was limited to the maternal tissues of the achene, including the pappus, pericarp, integument, and endosperm; but the embryo was never compromised. Resistant lettuce cultivars remained free of disease symptoms. Furthermore, V. dahliae colonization never progressed beyond infected lateral roots of resistant cultivars. Results indicated that resistance in lettuce may lie with the plant's ability to shed infected lateral roots or to inhibit the systemic progress of the fungus through vascular tissues into the taproot.

  6. Genome-wide association study discovered candidate genes of Verticillium wilt resistance in upland cotton (Gossypium hirsutum L.).

    Science.gov (United States)

    Li, Tinggang; Ma, Xuefeng; Li, Nanyang; Zhou, Lei; Liu, Zheng; Han, Huanyong; Gui, Yuejing; Bao, Yuming; Chen, Jieyin; Dai, Xiaofeng

    2017-12-01

    Verticillium wilt (VW), caused by infection by Verticillium dahliae, is considered one of the most yield-limiting diseases in cotton. To examine the genetic architecture of cotton VW resistance, we performed a genome-wide association study (GWAS) using a panel of 299 accessions and 85 630 single nucleotide polymorphisms (SNPs) detected using the specific-locus amplified fragment sequencing (SLAF-seq) approach. Trait-SNP association analysis detected a total of 17 significant SNPs at P resistance on A10 were continuous and common in three environments (RDIG2015, RDIF2015 and RDIF2016). Haplotype block structure analysis predicted 22 candidate genes for VW resistance based on A10_99672586 with a minimum P-value (-log10 P = 6.21). One of these genes (CG02) was near the significant SNP A10_99672586 (0.26 Mb), located in a 372-kb haplotype block, and its Arabidopsis AT3G25510 homologues contain TIR-NBS-LRR domains that may be involved in disease resistance response. Real-time quantitative PCR and virus-induced gene silencing (VIGS) analysis showed that CG02 was specific to up-regulation in the resistant (R) genotype Zhongzhimian2 (ZZM2) and that silenced plants were more susceptible to V. dahliae. These results indicate that CG02 is likely the candidate gene for resistance against V. dahliae in cotton. The identified locus or gene may serve as a promising target for genetic engineering and selection for improving resistance to VW in cotton. © 2017 The Authors. Plant Biotechnology Journal published by Society for Experimental Biology and The Association of Applied Biologists and John Wiley & Sons Ltd.

  7. The significance of ecology in the development of Verticillium chlamydosporium as a biological control agent against root-knot nematodes (Meloidogyne spp.)

    OpenAIRE

    Leij, de, F.A.A.M.

    1992-01-01

    A thorough understanding of the interactions which occur between nematode parasites and nematode pests and the influence of biotic and abiotic factors on these interactions, is essential in the development of biological control agents for nematodes. The aim of this study was to develop a particular isolate of the nematophagous fungus Verticillium chlamydosporium as a biological control agent for root-knot nematodes. The work has gained insight into some of the ke...

  8. Pressure surge attenuator

    Science.gov (United States)

    Christie, Alan M.; Snyder, Kurt I.

    1985-01-01

    A pressure surge attenuation system for pipes having a fluted region opposite crushable metal foam. As adapted for nuclear reactor vessels and heads, crushable metal foam is disposed to attenuate pressure surges.

  9. Arabidopsis thaliana as a tool to identify traits involved in Verticillium dahliae biocontrol by the olive root endophyte Pseudomonas fluorescens PICF7

    Science.gov (United States)

    Maldonado-González, M. Mercedes; Bakker, Peter A. H. M.; Prieto, Pilar; Mercado-Blanco, Jesús

    2015-01-01

    The effective management of Verticillium wilts (VW), diseases affecting many crops and caused by some species of the soil-borne fungus Verticillium, is problematic. The use of microbial antagonists to control these pathologies fits modern sustainable agriculture criteria. Pseudomonas fluorescens PICF7 is an endophytic bacterium isolated from olive roots with demonstrated ability to control VW of olive caused by the highly virulent, defoliating (D) pathotype of Verticillium dahliae Kleb. However, the study of the PICF7-V. dahliae-olive tripartite interaction poses difficulties because of the inherent characteristics of woody, long-living plants. To overcome these problems we explored the use of the model plant Arabidopsis thaliana. Results obtained in this study showed that: (i) olive D and non-defoliating V. dahliae pathotypes produce differential disease severity in A. thaliana plants; (ii) strain PICF7 is able to colonize and persist in the A. thaliana rhizosphere but is not endophytic in Arabidopsis; and (iii) strain PICF7 controls VW in Arabidopsis. Additionally, as previously observed in olive, neither swimming motility nor siderophore production by PICF7 are required for VW control in A. thaliana, whilst cysteine auxotrophy decreased the effectiveness of PICF7. Moreover, when applied to the roots PICF7 controlled Botrytis cinerea infection in the leaves of Arabidopsis, suggesting that this strain is able to induce systemic resistance. A. thaliana is therefore a suitable alternative to olive bioassays to unravel biocontrol traits involved in biological control of V. dahliae by P. fluorescens PICF7. PMID:25904904

  10. Characterization, Expression, and Functional Analysis of a Novel NAC Gene Associated with Resistance to Verticillium Wilt and Abiotic Stress in Cotton.

    Science.gov (United States)

    Wang, Weina; Yuan, Youlu; Yang, Can; Geng, Shuaipeng; Sun, Quan; Long, Lu; Cai, Chaowei; Chu, Zongyan; Liu, Xin; Wang, Guanghao; Du, Xiongming; Miao, Chen; Zhang, Xiao; Cai, Yingfan

    2016-12-07

    Elucidating the mechanism of resistance to biotic and abiotic stress is of great importance in cotton. In this study, a gene containing the NAC domain, designated GbNAC1, was identified from Gossypium barbadense L. Homologous sequence alignment indicated that GbNAC1 belongs to the TERN subgroup. GbNAC1 protein localized to the cell nucleus. GbNAC1 was expressed in roots, stems, and leaves, and was especially highly expressed in vascular bundles. Functional analysis showed that cotton resistance to Verticillium wilt was reduced when the GbNAC1 gene was silenced using the virus-induced gene silencing (VIGS) method. GbNAC1-overexpressing Arabidopsis showed enhanced resistance to Verticillium dahliae compared to wild-type. Thus, GbNAC1 is involved in the positive regulation of resistance to Verticillium wilt. In addition, analysis of GbNAC1-overexpressing Arabidopsis under different stress treatments indicated that it is involved in plant growth, development, and response to various abiotic stresses (ABA, mannitol, and NaCl). This suggests that GbNAC1 plays an important role in resistance to biotic and abiotic stresses in cotton. This study provides a foundation for further study of the function of NAC genes in cotton and other plants. Copyright © 2016 Wang et al.

  11. Isolation and characterization of a chitinase gene from entomopathogenic fungus Verticillium lecanii Isolamento e caracterização de um gene de quitinase do fungo entomopatogênico Verticillium lecanii

    Directory of Open Access Journals (Sweden)

    Yanping Zhu

    2008-06-01

    Full Text Available Entomopathogenic fungus Verticillium lecanii is a promising whitefly and aphid control agent. Chitinases secreted by this insect pathogen have considerable importance in the biological control of some insect pests. An endochitinase gene Vlchit1 from the fungus was cloned and overexpressed in Escherichia coli. The Vlchit1 gene not only contains an open reading frame (ORF which encodes a protein of 423 amino acids (aa, but also is interrupted by three short introns. A homology modelling of Vlchit1 protein showed that the chitinase Vlchit1 has a (α/β8 TIM barrel structure. Overexpression test and Enzymatic activity assay indicated that the Vlchit1 is a functional enzyme that can hydrolyze the chitin substrate, so the Vlchit1 gene can service as a useful gene source for genetic manipulation leading to strain improvement of entomopathogenic fungi or constructing new transgenic plants with resistance to various fungal and insects pests.O fungo entomopatogênico Verticillium lecanii é um agente promissor no controle da mosca-branca e do pulgão. As quitinases secretadas por esse patógeno de insetos têm uma grande importância no controle biológico de doenças causadas por insetos. Um gene de endoquitinase Vlchit1 desse fungo foi clonado e expresso em Escherichia coli. O gene Vlchit contém não apenas um ORF que codifica uma proteína de 423 aminoácidos, mas também é interrompido por três pequenos introns. A modelagem de homologia da proteína Vlchit1indicou que a quitinase Vlchit1 tem uma estrutura (α/β 8 TIM barrel. Testes de expressão e de atividade enzimática indicaram que Vlchit1 é uma enzima funcional que hidroliza quitina, portanto o gene Vlchit pode ser um gene útil para manipulação genética para melhoramento de cepas de fungos entomopatogênicos ou para a construção de novas plantas transgênicas com resistência a várias doenças causadas por fungos e insetos.

  12. Detection of Verticillium wilt of olive trees and downy mildew of opium poppy using hyperspectral and thermal UAV imagery

    Science.gov (United States)

    Calderón Madrid, Rocío; Navas Cortés, Juan Antonio; Montes Borrego, Miguel; Landa del Castillo, Blanca Beatriz; Lucena León, Carlos; Jesús Zarco Tejada, Pablo

    2014-05-01

    The present study explored the use of high-resolution thermal, multispectral and hyperspectral imagery as indicators of the infections caused by Verticillium wilt (VW) in olive trees and downy mildew (DM) in opium poppy fields. VW, caused by the soil-borne fungus Verticillium dahliae, and DM, caused by the biotrophic obligate oomycete Peronospora arborescens, are the most economically limiting diseases of olive trees and opium poppy, respectively, worldwide. V. dahliae infects the plant by the roots and colonizes its vascular system, blocking water flow and eventually inducing water stress. P. arborescens colonizes the mesophyll, appearing the first symptoms as small chlorotic leaf lesions, which can evolve to curled and thickened tissues and systemic infections that become deformed and necrotic as the disease develops. The work conducted to detect VW and DM infection consisted on the acquisition of time series of airborne thermal, multispectral and hyperspectral imagery using 2-m and 5-m wingspan electric Unmanned Aerial Vehicles (UAVs) in spring and summer of three consecutive years (2009 to 2011) for VW detection and on three dates in spring of 2009 for DM detection. Two 7-ha commercial olive orchards naturally infected with V. dahliae and two opium poppy field plots artificially infected by P. arborescens were flown. Concurrently to the airborne campaigns, olive orchards and opium poppy fields were assessed "in situ" to assess actual VW severity and DM incidence. Furthermore, field measurements were conducted at leaf and crown level. The field results related to VW detection showed a significant increase in crown temperature (Tc) minus air temperature (Ta) and a decrease in leaf stomatal conductance (G) as VW severity increased. This reduction in G was associated with a significant increase in the Photochemical Reflectance Index (PRI570) and a decrease in chlorophyll fluorescence. DM asymptomatic leaves showed significantly higher NDVI and lower green/red index

  13. The effect of pH on the production of chitinolytic enzymes of Verticillium fungicola in submerged cultures.

    Science.gov (United States)

    Ramirez-Coutiño, Laura; Espinosa-Marquez, Jesús; Peter, Martin G; Shirai, Keiko

    2010-12-01

    Chitinase and N-acetylhexosaminidase activities in submerged cultures of Verticillium fungicola increased up to 5-fold and 2.5-fold, respectively when the pH of the culture medium was raised from 5 to 8. SDS-PAGE and zymograms of the freeze-dried crude enzyme obtained from the cultures indicated four chitin degrading proteins of M(w) 24, 40, 55 and 63 kDa, whereas isoelectric focusing displayed the separation of three chitin degrading enzymes with isoelectric points of 4.7, 6.8 and 10, as well as two N-acetylhexosaminidases having isoelectric points of 3.2 and 13. Freeze-dried crude enzyme was characterized for its ability to produce chito-oligosaccharides from chitosans. Matrix-assisted laser desorption ionization time of flight mass spectrometry analyses revealed that monomers as well as hetero-oligomers with degree of polymerization 4 were initially the main products, whereas oligomers with degree of polymerization 2-11 were detected after extended reaction times. 2010 Elsevier Ltd. All rights reserved.

  14. Manipulating inoculum densities of Verticillium dahliae and Pratylenchus penetrans with green manure amendments and solarization influence potato yield.

    Science.gov (United States)

    Macguidwin, A E; Knuteson, D L; Connell, T; Bland, W L; Bartelt, K D

    2012-05-01

    We used cover crops with demonstrated efficacy against Verticillium dahliae and Pratylenchus penetrans in combination with the biocidal practice of solarization to determine the importance of targeting both organisms for managing potato early dying, an issue relevant to the search for alternatives to soil fumigation. Two experiments were conducted in commercial fields using a split-plot design with cover crop treatments of rapeseed, marigold, forage pearl millet, sorghum-sudangrass, and corn as the main plot factor and solarization as the subplot factor. Cover crops were grown and solarization applied in year one, followed by potato in year two. The main effect of solarization was significant for reduced inoculum levels of both organisms in year two and increased tuber yields. The main effect of cover crop was also significant with lower population densities of P. penetrans following the marigold and millet treatments and of V. dahliae following rape and sorghum-sudangrass. The cover crop treatments influenced yield in only one of the experiments in the absence of solarization. The combinatorial effect of cover crops and solarization resulted in a wide range of pathogen population densities. Mean soil inoculum levels were negatively related to yield for V. dahliae in experiment 1, and for P. penetrans and the P. penetrans × V. dahliae interaction in both experiments.

  15. Suppression of the homeobox gene HDTF1 enhances resistance to Verticillium dahliae and Botrytis cinerea in cotton.

    Science.gov (United States)

    Gao, Wei; Long, Lu; Xu, Li; Lindsey, Keith; Zhang, Xianlong; Zhu, Longfu

    2016-05-01

    Development of pathogen-resistant crops, such as fungus-resistant cotton, has significantly reduced chemical application and improved crop yield and quality. However, the mechanism of resistance to cotton pathogens such as Verticillium dahliae is still poorly understood. In this study, we characterized a cotton gene (HDTF1) that was isolated following transcriptome profiling during the resistance response of cotton to V. dahliae. HDTF1 putatively encodes a homeodomain transcription factor, and its expression was found to be down-regulated in cotton upon inoculation with V. dahliae and Botrytis cinerea. To characterise the involvement of HDTF1 in the response to these pathogens, we used virus-induced gene silencing (VIGS) to generate HDTF1-silenced cotton. VIGS reduction in HDTF1 expression significantly enhanced cotton plant resistance to both pathogens. HDTF1 silencing resulted in activation of jasmonic acid (JA)-mediated signaling and JA accumulation. However, the silenced plants were not altered in the accumulation of salicylic acid (SA) or the expression of marker genes associated with SA signaling. These results suggest that HDTF1 is a negative regulator of the JA pathway, and resistance to V. dahliae and B. cinerea can be engineered by activation of JA signaling. © 2015 Institute of Botany, Chinese Academy of Sciences.

  16. Perturbations in the Primary Metabolism of Tomato and Arabidopsis thaliana Plants Infected with the Soil-Borne Fungus Verticillium dahliae.

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    Anja Buhtz

    Full Text Available The hemibiotrophic soil-borne fungus Verticillium dahliae is a major pathogen of a number of economically important crop species. Here, the metabolic response of both tomato and Arabidopsis thaliana to V. dahliae infection was analysed by first using non-targeted GC-MS profiling. The leaf content of both major cell wall components glucuronic acid and xylose was reduced in the presence of the pathogen in tomato but enhanced in A. thaliana. The leaf content of the two tricarboxylic acid cycle intermediates fumaric acid and succinic acid was increased in the leaf of both species, reflecting a likely higher demand for reducing equivalents required for defence responses. A prominent group of affected compounds was amino acids and based on the targeted analysis in the root, it was shown that the level of 12 and four free amino acids was enhanced by the infection in, respectively, tomato and A. thaliana, with leucine and histidine being represented in both host species. The leaf content of six free amino acids was reduced in the leaf tissue of diseased A. thaliana plants, while that of two free amino acids was raised in the tomato plants. This study emphasizes the role of primary plant metabolites in adaptive responses when the fungus has colonized the plant.

  17. VdPKS1 is required for melanin formation and virulence in a cotton wilt pathogen Verticillium dahliae.

    Science.gov (United States)

    Zhang, Ting; Zhang, Bosen; Hua, Chenlei; Meng, Pei; Wang, Sheng; Chen, Zhirong; Du, Yejuan; Gao, Feng; Huang, Jiafeng

    2017-08-01

    Verticillium dahliae is a soil-borne phytopathogenic fungus that causes vascular wilt disease in a broad range of hosts. This pathogen survives for many years in soil in the form of melanized microsclerotia. To investigate the melanin synthesis in V. dahliae, we identified a polyketide synthase gene in V. dahliae, namely VdPKS1. PKS1 is known to involve in the dihydroxynaphthalene melanin synthesis pathway in many fungi. We found that VdPKS1 was required for melanin formation but not for microsclerotial production in V. dahliae. The VdPKS1 gene-disruption mutant (vdpks1) formed melanin-deficient albino microsclerotia, which did not affect the fungal colonization in host tissues but significantly reduced the disease severity. Gene transcription analysis in the wild-type and the vdpks1 strains suggested that VdPKS1 gene-disruption influenced the expression of a series of genes involved in ethylene biosynthesis, microsclerotial formation and pathogenesis. Our results suggest that the VdPKS1-mediated melanin synthesis is important for virulence and developmental traits of V. dahliae.

  18. PENGARUH INFESTASI VERTICILLIUM LECANII TERHADAP KEPARAHAN PENYAKIT KARAT DAUN KOPI PADA TANAMAN DAN KETERJADIAN KOLONINYA PADA DAUN

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    Cipta Ginting .

    2011-11-01

    Full Text Available Effect of infestation of Verticillium lecanii on the severity of coffee leaf rust on plants and the incidence of its colony on coffee leaves.  V. lecanii often antagonizes H. vastatrix on lesions caused by the pathogen on coffee leaves in the field.  The objectives of this study were to evaluate the efficacy of V. lecanii to control disease severity on coffee plants in a green house and to compare the incidence of V. lecanii colonies on coffee leaves naturally infested by V. lecanii in the field and that in the leaves with additional infestation in the laboratory.  For efficacy test and additional infestation in the laboratory, conidia were harvested from YMPD medium.  Suspension with 107 conidia ml-1 was sprayed into coffee foliage until both surfaces of the leaves were saturated with the suspension.  After the leaves were air dried, they were sprayed with urediospores (104 ml-1.  The results show that disease severity in plants treated with V. lecanii and control plants was not significantly different (P < 0.05, except that obtained at the fourth week when disease severity on the treated plants was significantly lower that that in control plants.  The number of V. lecanii colonies on coffee leaves naturally infested with the biocontrol agent was not increased by additional infestation with V. lecanii conidia in the laboratory.

  19. Genotyping-by-sequencing-based genome-wide association studies on Verticillium wilt resistance in autotetraploid alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Yu, Long-Xi; Zheng, Ping; Zhang, Tiejun; Rodringuez, Jonas; Main, Dorrie

    2017-02-01

    Verticillium wilt (VW) is a fungal disease that causes severe yield losses in alfalfa. The most effective method to control the disease is through the development and use of resistant varieties. The identification of marker loci linked to VW resistance can facilitate breeding for disease-resistant alfalfa. In the present investigation, we applied an integrated framework of genome-wide association with genotyping-by-sequencing (GBS) to identify VW resistance loci in a panel of elite alfalfa breeding lines. Phenotyping was performed by manual inoculation of the pathogen to healthy seedlings, and scoring for disease resistance was carried out according to the standard test of the North America Alfalfa Improvement Conference (NAAIC). Marker-trait association by linkage disequilibrium identified 10 single nucleotide polymorphism (SNP) markers significantly associated with VW resistance. Alignment of the SNP marker sequences to the M. truncatula genome revealed multiple quantitative trait loci (QTLs). Three, two, one and five markers were located on chromosomes 5, 6, 7 and 8, respectively. Resistance loci found on chromosomes 7 and 8 in the present study co-localized with the QTLs reported previously. A pairwise alignment (blastn) using the flanking sequences of the resistance loci against the M. truncatula genome identified potential candidate genes with putative disease resistance function. With further investigation, these markers may be implemented into breeding programmes using marker-assisted selection, ultimately leading to improved VW resistance in alfalfa. PUBLISHED 2016. THIS ARTICLE IS A U.S. GOVERNMENT WORK AND IS IN THE PUBLIC DOMAIN IN THE USA.

  20. Cepa de Trichoderma útil para el tratamiento y/o prevención de infecciones provocadas por hongos pertenecientes al género Verticillium

    OpenAIRE

    Barroso-Albarracín, Juan Bautista; Chaki, Mounira; Mercado-Blanco, Jesús; Valverde-Corredor, Antonio; López García, Antonio Alejandro

    2011-01-01

    La invención se refiere al uso de la cepa de hongos Trichoderma harzianum CECT 2413 para la prevención y/o tratamiento de infecciones de plantas y/o suelos provocadas por hongos fitopatógenos pertenecientes al género Verticíllium, preferiblemente por los patotipos defoliante o no defoliante de Verticillium dahliae, agente causante de la Verticilosis del olivo. Además, la invención propone el uso de esta cepa de hongos en combinación con otros hongos del género Trichoderma.

  1. In vitro effect of essential oils from aromatic and medicinal plants on mushroom pathogens: Verticillium fungicola var. fungicola, Mycogone perniciosa, and Cladobotryum sp.

    Directory of Open Access Journals (Sweden)

    Tanović Brankica

    2009-01-01

    Full Text Available Lavender, anise, chamomile, fennel, geranium, oregano, parsley, and sage essential oils were tested for their effectiveness against mushroom pathogens: Verticillium fungicola var. fungicola, Mycogone perniciosa, and Cladobotryum sp. Isolates were exposed to the volatile phase of the oils and then ventilated in order to determine if the effect of the oil was lethal to the pathogen. Oregano and geranium oils were the most toxic, having a fungicidal effect at 0.02-0.08 μl/ml of air, depending on the pathogen. Oregano oil was characterized by high content of carvacrol and thymol, while citranelol and geraniol were the main components of geranium oil.

  2. Grafted eggplant yield, quality and growth in infested soil with Verticillium dahliae and Meloidogyne incognita Produção, qualidade e crescimento de beringela enxertada, em solo infestado com Verticillium dahliae e Meloidogyne incognita

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    Sebahattin Çürük

    2009-12-01

    Full Text Available The objective of this work was to evaluate the effect of grafting (onto Solanum torvum Sw. on plant growth, yield and fruit quality of the Pala and Faselis eggplant (Solanum melongena L. cultivars, grown in a soil infested with Verticillium dahliae Kleb. and Meloidogyne incognita, or in noninfested soil. Soil infestation decreased yield, plant height, final above-ground biomass, and also reduced fruit mean weight and shoot dry weight depending on cultivar or grafting. Grafting decreased fruit oxalic acid and the soluble solid contents, and increased mean fruit weight, depending on cultivar and soil infestation. Grafting also reduced the negative effects of the pathogens on disease index, plant height and shoot dry weight. Cultivar Pala was more vigorous than Faselis, and S. torvum was a vigorous rootstock. The combination of a vigorous rootstock with a weak cultivar (Faselis is more profitable than that of a vigorous rootstock and a vigorous cultivar (Pala. Using S. torvum as a rootstock for cultivar Faselis, grown in soil infested with the pathogens, is most likely to be useful in conventional and low-input sustainable horticulture, since grafting increases protection against the pathogens, and reduces the losses in quality and yield.O objetivo deste trabalho foi avaliar o efeito sobre a altura de planta, a produção e a qualidade de frutos do enxerto das cultivares de beringela (Solanum melongena L. Pala e Faselis em Solanum torvum Sw., quando cultivadas em solo infestado com Verticillium dahliae e Meloidogyne incognita ou em solo não infestado. A infestação do solo reduziu a produção, altura da planta, biomassa da parte aérea, massa média dos frutos, massa de matéria seca da parte aérea, conforme a cultivar utilizada e a enxertia. A enxertia reduziu os conteúdos de ácido oxálico e de sólidos solúveis e aumentou a massa média de frutos, conforme a cultivar ou a presença do patógeno no solo. A enxertia também reduziu o efeito

  3. Landing gear noise attenuation

    Science.gov (United States)

    Moe, Jeffrey W. (Inventor); Whitmire, Julia (Inventor); Kwan, Hwa-Wan (Inventor); Abeysinghe, Amal (Inventor)

    2011-01-01

    A landing gear noise attenuator mitigates noise generated by airframe deployable landing gear. The noise attenuator can have a first position when the landing gear is in its deployed or down position, and a second position when the landing gear is in its up or stowed position. The noise attenuator may be an inflatable fairing that does not compromise limited space constraints associated with landing gear retraction and stowage. A truck fairing mounted under a truck beam can have a compliant edge to allow for non-destructive impingement of a deflected fire during certain conditions.

  4. Threshold microsclerotial inoculum for cotton verticillium wilt determined through wet-sieving and real-time quantitative PCR.

    Science.gov (United States)

    Wei, Feng; Fan, Rong; Dong, Haitao; Shang, Wenjing; Xu, Xiangming; Zhu, Heqin; Yang, Jiarong; Hu, Xiaoping

    2015-02-01

    Quantification of Verticillium dahliae microsclerotia is an important component of wilt management on a range of crops. Estimation of microsclerotia by dry or wet sieving and plating of soil samples on semiselective medium is a commonly used technique but this method is resource-intensive. We developed a new molecular quantification method based on Synergy Brands (SYBR) Green real-time quantitative polymerase chain reaction of wet-sieving samples (wet-sieving qPCR). This method can detect V. dahliae microsclerotia as low as 0.5 CFU g(-1) of soil. There was a high correlation (r=0.98) between the estimates of conventional plating analysis and the new wet-sieving qPCR method for 40 soil samples. To estimate the inoculum threshold for cotton wilt, >400 soil samples were taken from the rhizosphere of individual plants with or without visual wilt symptoms in experimental and commercial cotton fields at the boll-forming stage. Wilt inoculum was estimated using the wet-sieving qPCR method and related to wilt development. The estimated inoculum threshold varied with cultivar, ranging from 4.0 and 7.0 CFU g(-1) of soil for susceptible and resistant cultivars, respectively. In addition, there was an overall relationship of wilt incidence with inoculum density across 31 commercial fields where a single composite soil sample was taken at each field, with an estimated inoculum threshold of 11 CFU g(-1) of soil. These results suggest that wilt risk can be predicted from the estimated soil inoculum density using the new wet-sieving qPCR method. We recommend the use of 4.0 and 7.0 CFU g(-1) as an inoculum threshold on susceptible and resistant cultivars, respectively, in practical risk prediction schemes.

  5. [Population dynamics and antagonism toward Fusarium oxysporium f. sp. Vasinfectum. and Verticillium dahliae Kleb of endophytic bacteria from cotton].

    Science.gov (United States)

    Li, Chunhong; Deng, Yuanyu; Zhao, Mingwen; Tang, Canming; Li, Shunpeng; Lv, Haiwei

    2009-09-01

    To explore population dynamics of endophytic bacteria and obtain antagonistic endophytic bacteria toward Verticillium dahliae Kleb (Vd), Fusarium oxysporium f. sp. Vasinfectum (Fov) from cotton. Root, stem and leaf samples were surface-disinfested, and subsequently used to isolate endophytic bacteria by diluting plate counting method. We assayed antagonism of the isolated endophytic bacteria toward three pathogens: Vd (V107, which is a highly virulent defoliating isolate and V396, which is a mildly virulent non-defoliating isolate), Fov (F108) using a dual culture method, and analyzed the 16S rDNA sequence of doubly antagonistic endophytic bacteria (DAEB) isolates toward both Vd and Fov. The population size of endophytic bacteria in root was significantly larger than that in leaf and stem. The populations at seedling stage were generally lower than those at the flowering/maturing stage in root, the populations in stem and leaf were fluctuant at different development stages, but variation law was not observed obviously. Furthermore, although no significant differences of the population densities in root were found among 6 cotton cultivars, the population densities in stem and leaf showed cultivar differences. The proportion of endophytic bacteria antagonizing Vd (V107, V396) and Fov (F108) in root was higher than that in stem/leaf, moreover, the amount of endophytic bacteria antagonizing toward V107 was less than that toward V396/F108. Based on 16S rDNA sequence analysis, all 44 DAEB isolates consisted of two phyla, i.e., Bacteroidetes (1 out of 44) and Proteobacteria (43 out of 44), and fell into 8 genera. The genus enterobacter (18 out of 44) and Pantoea (15 out of 44) were predominant. Notably, ten DAEB isolates demonstrated cotton. Endophytic bacteria in cotton could serve as a pool for discovering biocontrol agent toward cotton pathogens.

  6. Maintenance of sex-related genes and the co-occurrence of both mating types in Verticillium dahliae.

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    Dylan P G Short

    Full Text Available Verticillium dahliae is a cosmopolitan, soilborne fungus that causes a significant wilt disease on a wide variety of plant hosts including economically important crops, ornamentals, and timber species. Clonal expansion through asexual reproduction plays a vital role in recurring plant epidemics caused by this pathogen. The recent discovery of recombination between clonal lineages and preliminary investigations of the meiotic gene inventory of V. dahliae suggest that cryptic sex appears to be rare in this species. Here we expanded on previous findings on the sexual nature of V. dahliae. Only 1% of isolates in a global collection of 1120 phytopathogenic V. dahliae isolates contained the MAT1-1 idiomorph, whereas 99% contained MAT1-2. Nine unique multilocus microsatellite types comprised isolates of both mating types, eight of which were collected from the same substrate at the same time. Orthologs of 88 previously characterized sex-related genes from fungal model systems in the Ascoymycota were identified in the genome of V. dahliae, out of 93 genes investigated. Results of RT-PCR experiments using both mating types revealed that 10 arbitrarily chosen sex-related genes, including MAT1-1-1 and MAT1-2-1, were constitutively expressed in V. dahliae cultures grown under laboratory conditions. Ratios of non-synonymous (amino-acid altering to synonymous (silent substitutions in V. dahliae MAT1-1-1 and MAT1-2-1 sequences were indistinguishable from the ratios observed in the MAT genes of sexual fungi in the Pezizomycotina. Patterns consistent with strong purifying selection were also observed in 18 other arbitrarily chosen V. dahliae sex-related genes, relative to the patterns in orthologs from fungi with known sexual stages. This study builds upon recent findings from other laboratories and mounts further evidence for an ancestral or cryptic sexual stage in V. dahliae.

  7. Secretory proteins are delivered to the septin-organized penetration interface during root infection by Verticillium dahliae

    Science.gov (United States)

    Zhou, Ting-Ting; Zhao, Yun-Long

    2017-01-01

    Successful infection of the host requires secretion of effector proteins to evade or suppress plant immunity. Secretion of effectors in root-infecting fungal pathogens, however, remains unexplored. We previously reported that Verticillium dahliae, a root-infecting phytopathogenic fungus, develops a penetration peg from a hyphopodium to infect cotton roots. In this study, we report that a septin ring, requiring VdSep5, partitions the hyphopodium and the invasive hypha and form the specialized fungus-host interface. The mutant strain, VdΔnoxb, in which NADPH oxidase B (VdNoxB) is deleted, impaired formation of the septin ring at the hyphal neck, indicating that NADPH oxidases regulate septin ring organization. Using GFP tagging and live cell imaging, we observed that several signal peptide containing secreted proteins showed ring signal accumulation/secretion at the penetration interface surrounding the hyphal neck. Targeted mutation for VdSep5 reduced the delivery rate of secretory proteins to the penetration interface. Blocking the secretory pathway by disrupting the vesicular trafficking factors, VdSec22 and VdSyn8, or the exocyst subunit, VdExo70, also arrested delivery of the secreted proteins inside the hyphopodium. Reduced virulence was observed when cotton roots were infected with VdΔsep5, VdΔsec22, VdΔsyn8 and VdΔexo70 mutants compared to infection with the isogenic wild-type V592. Taken together, our data demonstrate that the hyphal neck is an important site for protein secretion during plant root infection, and that the multiple secretory routes are involved in the secretion. PMID:28282450

  8. Crescimento e esporulação de isolados de Verticillium lecanii sob diferentes condições nutricionais

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    Barbosa Claudio Camargo

    2002-01-01

    Full Text Available O objetivo deste trabalho foi determinar as melhores condições de crescimento e esporulação de dois isolados de Verticillium lecanii (Zimm. Viégas, cultivados em vários meios de cultura, fontes de C, fontes orgânicas e inorgânicas de N e relações C:N. Após 20 dias de cultivo, BDA e Meio Completo mostraram ser os melhores meios de cultura, e a lactose e o amido foram as fontes de C que mais favoreceram o crescimento dos isolados JAB 02 e JAB 45, respectivamente; baixa esporulação foi apresentada por JAB 02, enquanto JAB 45 obteve boa esporulação em glicose e maltose. JAB 02 desenvolveu melhor quando a fonte orgânica de N era casitona; JAB 45 obteve bom desenvolvimento em presença de casitona e peptona, mas houve pouca esporulação em presença de triptona e caseína hidrolisada. As fontes inorgânicas de N que favoreceram o melhor desenvolvimento dos isolados foram (NH42HPO4 e NaNO3, porém, JAB 02 apresentou baixa esporulação. Entre as relações C:N analisadas, JAB 02 obteve melhor crescimento na relação 60:1 e JAB 45 nas relações 5:1, 10:1 e 20:1; baixa esporulação foi obtida por JAB 02 nas relações testadas, mas não se verificou efeito da relação C:N do meio sobre a esporulação dos isolados.

  9. Characterization of a new partitivirus strain in Verticillium dahliae provides further evidence of the spread of the highly virulent defoliating pathotype through new introductions

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    Mari Carmen CAÑIZARES

    2015-12-01

    Full Text Available The soilborne pathogen Verticillium dahliae, causal agent of Verticillium wilt, has a worldwide distribution and many hosts of agronomic value. The worldwide spread of a highly virulent defoliating (D pathotype has greatly increased the threat posed by V. dahliae in olive trees. For effective disease management, it is important to know if the D pathotype is spreading long distances from contaminated material, or if D pathotype isolates may have originated locally from native V. dahliae populations several times. We identified a double-stranded RNA mycovirus in an olive D pathotype isolate from Turkey. Sequencing and phylogenetic analysis clustered the virus with members of the family Partitiviridae. The virus was most similar to a partitivirus previously identified in a V. dahliae isolate from cotton in China (VdPV1, with sequence identities of 94% and 91% at the nucleotide level for RNA1 and RNA2, respectively. The virus therefore corresponded to a strain of the established species, and we designated it VdPV1-ol (VdPV1 from olive. The identification of the same viral species in these two fungal isolates from geographically distant origins provides evidence of their relationships, supporting the hypothesis of long-distance movement of V. dahliae isolates.

  10. Identification of MiRNA from eggplant (Solanum melongena L. by small RNA deep sequencing and their response to Verticillium dahliae infection.

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    Liu Yang

    Full Text Available MiRNAs are a class of non-coding small RNAs that play important roles in the regulation of gene expression. Although plant miRNAs have been extensively studied in model systems, less is known in other plants with limited genome sequence data, including eggplant (Solanum melongena L.. To identify miRNAs in eggplant and their response to Verticillium dahliae infection, a fungal pathogen for which clear understanding of infection mechanisms and effective cure methods are currently lacking, we deep-sequenced two small RNA (sRNA libraries prepared from mock-infected and infected seedlings of eggplants. Specifically, 30,830,792 reads produced 7,716,328 unique miRNAs representing 99 known miRNA families that have been identified in other plant species. Two novel putative miRNAs were predicted with eggplant ESTs. The potential targets of the identified known and novel miRNAs were also predicted based on sequence homology search. It was observed that the length distribution of obtained sRNAs and the expression of 6 miRNA families were obviously different between the two libraries. These results provide a framework for further analysis of miRNAs and their role in regulating plant response to fungal infection and Verticillium wilt in particular.

  11. Molecular mapping and validation of a major QTL conferring resistance to a defoliating isolate of verticillium wilt in cotton (Gossypium hirsutum L.).

    Science.gov (United States)

    Zhang, Xingju; Yuan, Yanchao; Wei, Ze; Guo, Xian; Guo, Yuping; Zhang, Suqing; Zhao, Junsheng; Zhang, Guihua; Song, Xianliang; Sun, Xuezhen

    2014-01-01

    Verticillium wilt (VW) caused by Verticillium dahliae Kleb is one of the most destructive diseases of cotton. Development and use of a VW resistant variety is the most practical and effective way to manage this disease. Identification of highly resistant genes/QTL and the underlining genetic architecture is a prerequisite for developing a VW resistant variety. A major QTL qVW-c6-1 conferring resistance to the defoliating isolate V991 was identified on chromosome 6 in LHB22×JM11 F2∶3 population inoculated and grown in a greenhouse. This QTL was further validated in the LHB22×NNG F2∶3 population that was evaluated in an artificial disease nursery of V991 for two years and in its subsequent F4 population grown in a field severely infested by V991. The allele conferring resistance within the QTL qVW-c6-1 region originated from parent LHB22 and could explain 23.1-27.1% of phenotypic variation. Another resistance QTL qVW-c21-1 originated from the susceptible parent JM11 was mapped on chromosome 21, explaining 14.44% of phenotypic variation. The resistance QTL reported herein provides a useful tool for breeding a cotton variety with enhanced resistance to VW.

  12. An endophytic Streptomyces sp. strain DHV3-2 from diseased root as a potential biocontrol agent against Verticillium dahliae and growth elicitor in tomato (Solanum lycopersicum).

    Science.gov (United States)

    Cao, Peng; Liu, Chongxi; Sun, Pengyu; Fu, Xuepeng; Wang, Shaoxian; Wu, Fengzhi; Wang, Xiangjing

    2016-12-01

    Plant endophytes play important roles in biocontrol of plant diseases. Actinomycetes are used for biocontrol of fungal diseases caused by Verticillium dahliae. Many studies have focused on the endophytic actinomycetes isolated from the roots of healthy plants, but few on those from the roots of diseased plants. In the present research, actinomycetes were isolated from the roots of diseased and healthy tomato plants, respectively. The results showed that, in total, 86 endophytic actinomycetes were isolated for screening of their antimicrobial activities, 8 of which showed antagonism to V. dahliae in vitro. Among the 8 antagonistic strains, 5 (out of 36) were from the roots of diseased plants, with inhibition diameter zones ranging from 11.2 to 18.2 mm, whereas 3 (out of 50) were from the roots of healthy plants, with inhibition diameter zones ranging from 11.5 to 15.5 mm. Endophytic strain DHV3-2 was isolated from the root of a diseased plant and demonstrated a potent effect against V. dahliae and other pathogenic fungi by showing the largest inhibition diameter zones among all the eight antagonistic strains. Thus, strain DHV3-2 was chosen to investigate its biological control efficacies in vivo. Further study showed that the disease incidence and disease severity indices of tomato Verticillium wilt decreased significantly (P biocontrol agent against V. dahliae and growth elicitor in tomato.

  13. Ectopic expression of a Ve homolog VvVe gene from Vitis vinifera enhances defense response to Verticillium dahliae infection in tobacco.

    Science.gov (United States)

    Tang, Juan; Lin, Jing; Yang, Yuwen; Chen, Tianzi; Ling, Xitie; Zhang, Baolong; Chang, Youhong

    2016-01-15

    Verticillium wilt is a soil borne disease that can cause devastating losses to the production of many economically important crops. A Ve1 homologous gene responding to Verticillium dahliae infection was identified in Vitis vinifera cv. "HeiFeng" by semi-quantitative reverse transcription polymerase chain reaction and was designated as VvVe. The overexpression of VvVe in transgenic Nicotiana benthamiana plants significantly enhanced the resistance to isolate V991 of V. dahliae when compared with the wild type plants. The expressions of defense-related genes including the salicylic acid regulated gene pathogen-related 1 (PR1) but not PR2, the ethylene- and jasmonic acid-regulated genes ethylene response factor 1 (ERF1) and lipoxygenase (LOX) were significantly increased due to over expression of VvVe. And greater accumulation of active oxygen, callose and phenylalanine-ammonia lyase were observed in the leaves of transgenic VvVe tobacco plants than the wild type when under infection by V. dahliae. Moreover, the hypersensitive response mimicking cell death was exclusively occurred in the transgenic VvVe tobacco plants but not in the wild type. Taken together, the VvVe gene is a Ve1 like gene which involves in the signal cascade of salicylic acid, jasmonate, and ethylene defense pathways and enhances defense response to V. dahliae infection in the transgenic tobacco. Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Colonization process of olive tissues by Verticillium dahliae and its in planta interaction with the biocontrol root endophyte Pseudomonas fluorescens PICF7

    Science.gov (United States)

    Prieto, Pilar; Navarro‐Raya, Carmen; Valverde‐Corredor, Antonio; Amyotte, Stefan G.; Dobinson, Katherine F.; Mercado‐Blanco, Jesús

    2009-01-01

    Summary The colonization process of Olea europaea by the defoliating pathotype of Verticillium dahliae, and the in planta interaction with the endophytic, biocontrol strain Pseudomonas fluorescens PICF7 were determined. Differential fluorescent protein tagging was used for the simultaneous visualization of P. fluorescens PICF7 and V. dahliae in olive tissues. Olive plants were bacterized with PICF7 and then transferred to V. dahliae‐infested soil. Monitoring olive colonization events by V. dahliae and its interaction with PICF7 was conducted using a non‐gnotobiotic system, confocal laser scanner microscopy and tissue vibratoming sections. A yellow fluorescently tagged V. dahliae derivative (VDAT‐36I) was obtained by Agrobacterium tumefaciens‐mediated transformation. Isolate VDAT‐36I quickly colonized olive root surface, successfully invaded root cortex and vascular tissues via macro‐ and micro‐breakages, and progressed to the aerial parts of the plant through xylem vessel cells. Strain PICF7 used root hairs as preferred penetration site, and once established on/in root tissues, hindered pathogen colonization. For the first time using this approach, the entire colonization process of a woody plant by V. dahliae is reported. Early and localized root surface and root endophytic colonization by P. fluorescens PICF7 is needed to impair full progress of verticillium wilt epidemics in olive. PMID:21255281

  15. Radiofrequency attenuator and method

    Science.gov (United States)

    Warner, Benjamin P [Los Alamos, NM; McCleskey, T Mark [Los Alamos, NM; Burrell, Anthony K [Los Alamos, NM; Agrawal, Anoop [Tucson, AZ; Hall, Simon B [Palmerston North, NZ

    2009-01-20

    Radiofrequency attenuator and method. The attenuator includes a pair of transparent windows. A chamber between the windows is filled with molten salt. Preferred molten salts include quarternary ammonium cations and fluorine-containing anions such as tetrafluoroborate (BF.sub.4.sup.-), hexafluorophosphate (PF.sub.6.sup.-), hexafluoroarsenate (AsF.sub.6.sup.-), trifluoromethylsulfonate (CF.sub.3SO.sub.3.sup.-), bis(trifluoromethylsulfonyl)imide ((CF.sub.3SO.sub.2).sub.2N.sup.-), bis(perfluoroethylsulfonyl)imide ((CF.sub.3CF.sub.2SO.sub.2).sub.2N.sup.-) and tris(trifluoromethylsulfonyl)methide ((CF.sub.3SO.sub.2).sub.3C.sup.-). Radicals or radical cations may be added to or electrochemically generated in the molten salt to enhance the RF attenuation.

  16. Study on interaction between root-knot nematode Meloidogyne javanica and wilt fungus Verticillium dahliae on olive seedlings in greenhouse.

    Science.gov (United States)

    Saeedizadeh, A; Kheiri, A; Okhovat, M; Hoseininejad, A

    2003-01-01

    Verticillium dahliae has been reported as a limiting factor in cotton, olive, potato and tomato fields from several countries in the world. Root-knot nematodes Meloidogyne javanica causes considerable damage to olive groves in olive growing areas. Since the presence of these two pathogens in olive trees and seedlings were confirmed in Golestan Province, this study was proposed to find the mode of their action and interaction with olive seedlings in greenhouse. The non-defoliant strain of the fungus (SS-4) was isolated from olive groves showing symptom in Golestan Province. M. javanica was also recovered from the infested olive seedlings. After species identification, it was reared on tomato seedlings var. Rutgers. The larvae were used as a source of inoculum. Conidia and microsclerotia of V. dahliae were used as a source of inoculum for pathogenesis in this study. Stem cuttings of olive cultivar Zard were transplanted in different sets of pots containing 720 ml. of sterilized loamy soil and sandy soil. Experiment was conducted in Completely Randomized Design with 6 treatments and 8 replicates including control, nematode alone, fungus alone, nematode and fungus simultaneously, nematode and fungus concomitantly, fungus two weeks prior to nematode, nematode and fungus concomitantly, nematode two weeks prior to fungus. Pots were inoculated with 1500 larvae of nematodes and 7200 microsclerotia of V. dahliae. Experiment was terminated after 9 months and following parameters were determined i.e. fresh weight of roots, number of galls and females, per root system and discoloration of leaf and root tissues. Presence of nematode prior to fungus caused reduction in colonization of fungus in the roots and the stems and vis presence of fungus prior to nematode caused reduction in number of galls produced by nematode. Sever symptom on aerial parts of plant was observed when both pathogens were inoculated simultaneously. However fresh weight of roots was reduced in all treatments

  17. Natural attenuation of herbicides

    DEFF Research Database (Denmark)

    Tuxen, Nina; Højberg, Anker Lajer; Broholm, Mette Martina

    2002-01-01

    A field injection experiment in a sandy, aerobic aquifer showed that two phenoxy acids MCPP (mecoprop) and dichlorprop were degraded within I in downgradient of the injection wells after an apparent lag period. The plume development and microbial measurements indicated that microbial growth....... The observations may be important for application of natural attenuation as a remedy in field scale systems....

  18. Proteomic and Virus-induced Gene Silencing (VIGS) Analyses Reveal That Gossypol, Brassinosteroids, and Jasmonic acid Contribute to the Resistance of Cotton to Verticillium dahliae *

    Science.gov (United States)

    Gao, Wei; Long, Lu; Zhu, Long-Fu; Xu, Li; Gao, Wen-Hui; Sun, Long-Qing; Liu, Lin-Lin; Zhang, Xian-Long

    2013-01-01

    Verticillium wilt causes massive annual losses of cotton yield, but the mechanism of cotton resistance to Verticillium dahliae is complex and poorly understood. In this study, a comparative proteomic analysis was performed in resistant cotton (Gossypium barbadense cv7124) on infection with V. dahliae. A total of 188 differentially expressed proteins were identified by mass spectrometry (MALDI-TOF/TOF) analysis and could be classified into 17 biological processes based on Gene Ontology annotation. Most of these proteins were implicated in stimulus response, cellular processes and metabolic processes. Based on the proteomic analysis, several genes involved in secondary metabolism, reactive oxygen burst and phytohormone signaling pathways were identified for further physiological and molecular analysis. The roles of the corresponding genes were further characterized by employing virus-induced gene silencing (VIGS). Based on the results, we suggest that the production of gossypol is sufficient to affect the cotton resistance to V. dahliae. Silencing of GbCAD1, a key enzyme involving in gossypol biosynthesis, compromised cotton resistance to V. dahliae. Reactive oxygen species and salicylic acid signaling may be also implicated as regulators in cotton responsive to V. dahliae according to the analysis of GbSSI2, an important regulator in the crosstalk between salicylic acid and jasmonic acid signal pathways. Moreover, brassinosteroids and jasmonic acid signaling may play essential roles in the cotton disease resistance to V. dahliae. The brassinosteroids signaling was activated in cotton on inoculation with V. dahliae and the disease resistance of cotton was enhanced after exogenous application of brassinolide. Meanwhile, jasmonic acid signaling was also activated in cotton after inoculation with V. dahliae and brassinolide application. These data provide highlights in the molecular basis of cotton resistance to V. dahliae. PMID:24019146

  19. Proteomic and virus-induced gene silencing (VIGS) Analyses reveal that gossypol, brassinosteroids, and jasmonic acid contribute to the resistance of cotton to Verticillium dahliae.

    Science.gov (United States)

    Gao, Wei; Long, Lu; Zhu, Long-Fu; Xu, Li; Gao, Wen-Hui; Sun, Long-Qing; Liu, Lin-Lin; Zhang, Xian-Long

    2013-12-01

    Verticillium wilt causes massive annual losses of cotton yield, but the mechanism of cotton resistance to Verticillium dahliae is complex and poorly understood. In this study, a comparative proteomic analysis was performed in resistant cotton (Gossypium barbadense cv7124) on infection with V. dahliae. A total of 188 differentially expressed proteins were identified by mass spectrometry (MALDI-TOF/TOF) analysis and could be classified into 17 biological processes based on Gene Ontology annotation. Most of these proteins were implicated in stimulus response, cellular processes and metabolic processes. Based on the proteomic analysis, several genes involved in secondary metabolism, reactive oxygen burst and phytohormone signaling pathways were identified for further physiological and molecular analysis. The roles of the corresponding genes were further characterized by employing virus-induced gene silencing (VIGS). Based on the results, we suggest that the production of gossypol is sufficient to affect the cotton resistance to V. dahliae. Silencing of GbCAD1, a key enzyme involving in gossypol biosynthesis, compromised cotton resistance to V. dahliae. Reactive oxygen species and salicylic acid signaling may be also implicated as regulators in cotton responsive to V. dahliae according to the analysis of GbSSI2, an important regulator in the crosstalk between salicylic acid and jasmonic acid signal pathways. Moreover, brassinosteroids and jasmonic acid signaling may play essential roles in the cotton disease resistance to V. dahliae. The brassinosteroids signaling was activated in cotton on inoculation with V. dahliae and the disease resistance of cotton was enhanced after exogenous application of brassinolide. Meanwhile, jasmonic acid signaling was also activated in cotton after inoculation with V. dahliae and brassinolide application. These data provide highlights in the molecular basis of cotton resistance to V. dahliae.

  20. Fluid dynamic bowtie attenuators

    Science.gov (United States)

    Szczykutowicz, Timothy P.; Hermus, James

    2015-03-01

    Fluence field modulated CT allows for improvements in image quality and dose reduction. To date, only 1-D modulators have been proposed, the extension to 2-D modulation is difficult with solid-metal attenuation-based modulators. This work proposes to use liquids and gas to attenuate the x-ray beam which can be arrayed allowing for 2-D fluence modulation. The thickness of liquid and the pressure for a given path length of gas were determined that provided the same attenuation as 30 cm of soft tissue at 80, 100, 120, and 140 kV. Gaseous Xenon and liquid Iodine, Zinc Chloride, and Cerium Chloride were studied. Additionally, we performed some proof-of-concept experiments in which (1) a single cell of liquid was connected to a reservoir which allowed the liquid thickness to be modulated and (2) a 96 cell array was constructed in which the liquid thickness in each cell was adjusted manually. Liquid thickness varied as a function of kV and chemical composition, with Zinc Chloride allowing for the smallest thickness; 1.8, 2.25, 3, and 3.6 cm compensated for 30 cm of soft tissue at 80, 100, 120, and 140 kV respectively. The 96 cell Iodine attenuator allowed for a reduction in both dynamic range to the detector and scatter to primary ratio. Successful modulation of a single cell was performed at 0, 90, and 130 degrees using a simple piston/actuator. The thickness of liquids and the Xenon gas pressure seem logistically implementable within the constraints of CBCT and diagnostic CT systems.

  1. The Ve-mediated resistance response of the tomato to Verticillium dahliae involves H2O2, peroxidase and lignins and drives PAL gene expression

    Directory of Open Access Journals (Sweden)

    Merino Fuencisla

    2010-10-01

    Full Text Available Abstract Background Verticillium dahliae is a fungal pathogen that infects a wide range of hosts. The only known genes for resistance to Verticillium in the Solanaceae are found in the tomato (Solanum lycopersicum Ve locus, formed by two linked genes, Ve1 and Ve2. To characterize the resistance response mediated by the tomato Ve gene, we inoculated two nearly isogenic tomato lines, LA3030 (ve/ve and LA3038 (Ve/Ve, with V. dahliae. Results We found induction of H2O2 production in roots of inoculated plants, followed by an increase in peroxidase activity only in roots of inoculated resistant plants. Phenylalanine-ammonia lyase (PAL activity was also increased in resistant roots 2 hours after inoculation, while induction of PAL activity in susceptible roots was not seen until 48 hours after inoculation. Phenylpropanoid metabolism was also affected, with increases in ferulic acid, p-coumaric acid, vanillin and p-hydroxybenzaldehyde contents in resistant roots after inoculation. Six tomato PAL cDNA sequences (PAL1 - PAL6 were found in the SolGenes tomato EST database. RT-PCR analysis showed that these genes were expressed in all organs of the plant, albeit at different levels. Real-time RT-PCR indicated distinct patterns of expression of the different PAL genes in V. dahliae-inoculated roots. Phylogenetic analysis of 48 partial PAL cDNAs corresponding to 19 plant species grouped angiosperm PAL sequences into four clusters, suggesting functional differences among the six tomato genes, with PAL2 and PAL6 presumably involved in lignification, and the remaining PAL genes implicated in other biological processes. An increase in the synthesis of lignins was found 16 and 28 days after inoculation in both lines; this increase was greater and faster to develop in the resistant line. In both resistant and susceptible inoculated plants, an increase in the ratio of guaiacyl/syringyl units was detected 16 days after inoculation, resulting from the lowered amount

  2. Influence of soil type, cultivar and Verticillium dahliae on the structure of the root and rhizosphere soil fungal microbiome of strawberry.

    Science.gov (United States)

    Nallanchakravarthula, Srivathsa; Mahmood, Shahid; Alström, Sadhna; Finlay, Roger D

    2014-01-01

    Sustainable management of crop productivity and health necessitates improved understanding of the ways in which rhizosphere microbial populations interact with each other, with plant roots and their abiotic environment. In this study we examined the effects of different soils and cultivars, and the presence of a soil-borne fungal pathogen, Verticillium dahliae, on the fungal microbiome of the rhizosphere soil and roots of strawberry plants, using high-throughput pyrosequencing. Fungal communities of the roots of two cultivars, Honeoye and Florence, were statistically distinct from those in the rhizosphere soil of the same plants, with little overlap. Roots of plants growing in two contrasting field soils had high relative abundance of Leptodontidium sp. C2 BESC 319 g whereas rhizosphere soil was characterised by high relative abundance of Trichosporon dulcitum or Cryptococcus terreus, depending upon the soil type. Differences between different cultivars were not as clear. Inoculation with the pathogen V. dahliae had a significant influence on community structure, generally decreasing the number of rhizosphere soil- and root-inhabiting fungi. Leptodontidium sp. C2 BESC 319 g was the dominant fungus responding positively to inoculation with V. dahliae. The results suggest that 1) plant roots select microorganisms from the wider rhizosphere pool, 2) that both rhizosphere soil and root inhabiting fungal communities are influenced by V. dahliae and 3) that soil type has a stronger influence on both of these communities than cultivar.

  3. Real-Time PCR Detection and QUantification of Soilborne Fungal Pathogens : the Case of Rosellinia necatrix, Phytophthora nicotianae, P. citrophthora and Verticillium dahliae

    Directory of Open Access Journals (Sweden)

    L. Schena

    2004-08-01

    Full Text Available Conventional and Scorpion primers were designed from the ITS regions to identify Rosellinia necatrix, Phytophthora nicotianae, and P. citrophthora and from the IGS regions to identify Verticillium dahliae and V. alboatrum. Specificity of primers and probes was assessed using genomic DNA from a large number of fungi from several hosts and by means of BLAST analyses, to exclude the presence of similar sequences in other micro-organisms among available DNA databases (GenBank. Simple and rapid procedures for DNA extraction from naturally infected matrices (soils, roots, bark, and/or woody tissues were utilised to yield DNA of a purity and quality suitable for PCR assays. Combining these protocols with a double amplification (nested Scorpion-PCR, the real-time detection of these pathogens was possible from naturally infested soils and from infected citrus roots (P. nicotianae and P. citrophthora, from the roots and bark of stone fruits and olive (R. necatrix and from olive branches (V. dahliae. For target pathogens, the limit of detection was 1 pg µl-1 in Scorpion-PCR and 1 fg µl-1 in nested Scorpion-PCR. High and significant correlations between pathogen propagule concentrations and real-time PCR cycle thresholds (Ct were obtained. Moreover, specific tests with R. necatrix seem to indicate that its DNA is quite rapidly degraded in the soil, excluding the risk of false positives due to the presence of dead cells.

  4. Biological control of wilt disease complex on tomato crop caused by Meloidogyne javanica and Fusarium oxysporum f.sp. lycopersici by Verticillium leptobactrum.

    Science.gov (United States)

    Hajji-Hedfi, Lobna; Regaieg, Hajer; Larayedh, Asma; Chihani, Noura; Horrigue-Raouani, Najet

    2017-09-23

    The efficacy of Verticillium leptobactrum isolate (HR1) was evaluated in the control of root-knot nematode and Fusarium wilt fungus under laboratory and greenhouse conditions. Five concentrations of V. leptobactrum (HR1) isolate were tested for their nematicidal and fungicidal activities against Meloidogyne javanica and Fusarium oxysporum f.sp. lycopersici in vitro. Laboratory trials showed that mycelium growth inhibition of Fusarium wilt fungus was correlated to the increase of the concentration of culture filtrate. All dilutions showed efficiency in reducing the growth of Fusarium oxysporum f.sp. lycopersici. The greatest nematicidal activity was observed at 50, 75, and 100% filtrate dilutions. The egg hatching percentage reached 42%, and the juvenile's corrected mortality registered 90% for the above treatments. In greenhouse experiment, the biocontrol agent fungus enhanced significantly tomato growth components (height and weight of plant and root). The multiplication rate of root-knot nematode and the Fusarium wilt disease incidence declined significantly with soil application of V. leptobactrum as with chemical treatments. The isolate HR1 was efficient to control wilt disease complex caused by M. javanica and Fusarium oxysporum f.sp. lycopersici.

  5. Two Lysin-Motif Receptor Kinases, Gh-LYK1 and Gh-LYK2, Contribute to Resistance against Verticillium wilt in Upland Cotton

    Directory of Open Access Journals (Sweden)

    Zhouhang Gu

    2017-12-01

    Full Text Available Lysin-motif (LysM receptor kinases (LYKs play essential roles in recognition of chitin and activation of defense responses against pathogenic fungi in the model plants Arabidopsis and rice. The function of LYKs in non-model plants, however, remains elusive. In the present work, we found that the transcription of two LYK-encoding genes from cotton, Gh-LYK1 and Gh-LYK2, was induced after Verticillium dahliae infection. Virus-induced gene silencing (VIGS of Gh-LYK1 and Gh-LYK2 in cotton plants compromises resistance to V. dahliae. As putative pattern recognition receptors (PRRs, both Gh-LYK1 and Gh-LYK2 are membrane-localized, and all three LysM domains of Gh-LYK1 and Gh-LYK2 are required for their chitin-binding ability. However, since Gh-LYK2, but not Gh-LYK1, is a pseudo-kinase and, on the other hand, the ectodomain (ED of Gh-LYK2 can induce reactive oxygen species (ROS burst in planta, Gh-LYK2 and Gh-LYK1 may contribute differently to cotton defense. Taken together, our results establish that both Gh-LYK1 and Gh-LYK12 are required for defense against V. dahliae in cotton, possibly through different mechanisms.

  6. Comparative genomics reveals cotton-specific virulence factors in flexible genomic regions in Verticillium dahliae and evidence of horizontal gene transfer from Fusarium.

    Science.gov (United States)

    Chen, Jie-Yin; Liu, Chun; Gui, Yue-Jing; Si, Kai-Wei; Zhang, Dan-Dan; Wang, Jie; Short, Dylan P G; Huang, Jin-Qun; Li, Nan-Yang; Liang, Yong; Zhang, Wen-Qi; Yang, Lin; Ma, Xue-Feng; Li, Ting-Gang; Zhou, Lei; Wang, Bao-Li; Bao, Yu-Ming; Subbarao, Krishna V; Zhang, Geng-Yun; Dai, Xiao-Feng

    2018-01-01

    Verticillium dahliae isolates are most virulent on the host from which they were originally isolated. Mechanisms underlying these dominant host adaptations are currently unknown. We sequenced the genome of V. dahliae Vd991, which is highly virulent on its original host, cotton, and performed comparisons with the reference genomes of JR2 (from tomato) and VdLs.17 (from lettuce). Pathogenicity-related factor prediction, orthology and multigene family classification, transcriptome analyses, phylogenetic analyses, and pathogenicity experiments were performed. The Vd991 genome harbored several exclusive, lineage-specific (LS) genes within LS regions (LSRs). Deletion mutants of the seven genes within one LSR (G-LSR2) in Vd991 were less virulent only on cotton. Integration of G-LSR2 genes individually into JR2 and VdLs.17 resulted in significantly enhanced virulence on cotton but did not affect virulence on tomato or lettuce. Transcription levels of the seven LS genes in Vd991 were higher during the early stages of cotton infection, as compared with other hosts. Phylogenetic analyses suggested that G-LSR2 was acquired from Fusarium oxysporum f. sp. vasinfectum through horizontal gene transfer. Our results provide evidence that horizontal gene transfer from Fusarium to Vd991 contributed significantly to its adaptation to cotton and may represent a significant mechanism in the evolution of an asexual plant pathogen. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  7. Ectopic expression of a novel Ser/Thr protein kinase from cotton (Gossypium barbadense), enhances resistance to Verticillium dahliae infection and oxidative stress in Arabidopsis.

    Science.gov (United States)

    Zhang, Yan; Wang, Xingfen; Li, Yiyi; Wu, Lizhu; Zhou, Hongmei; Zhang, Guiyin; Ma, Zhiying

    2013-11-01

    Overexpression of a cotton defense-related gene GbSTK in Arabidopsis resulted in enhancing pathogen infection and oxidative stress by activating multiple defense-signaling pathways. Serine/threonine protein kinase (STK) plays an important role in the plant stress-signaling transduction pathway via phosphorylation. Most studies about STK genes have been conducted with model species. However, their molecular and biochemical characterizations have not been thoroughly investigated in cotton. Here, we focused on one such member, GbSTK. RT-PCR indicated that it is induced not only by Verticillium dahliae Kleb., but also by signaling molecules. Subcellular localization showed that GbSTK is present in the cell membrane, cytoplasm, and nucleus. Overexpression of GbSTK in Arabidopsis resulted into the enhanced resistance to V. dahliae. Moreover, Overexpression of GbSTK elevated the expression of PR4, PR5, and EREBP, conferring on transgenic plants enhanced reactive oxygen species scavenging capacity and oxidative stress tolerance. Our results suggest that GbSTK is active in multiple defense-signaling pathways, including those involved in responses to pathogen infection and oxidative stress.

  8. The pmk1-like mitogen-activated protein kinase from Lecanicillium (Verticillium) fungicola is not required for virulence on Agaricus bisporus.

    Science.gov (United States)

    Collopy, Patrick D; Amey, Richard C; Sergeant, Martin J; Challen, Michael P; Mills, Peter R; Foster, Gary D; Bailey, Andy M

    2010-05-01

    In plant-pathogenic fungi, the pmk1 mitogen-activated protein kinase (MAPK) signalling pathway plays an essential role in regulating the development of penetration structures and the sensing of host-derived cues, but its role in other pathosystems such as fungal-fungal interactions is less clear. We report the use of a gene disruption strategy to investigate the pmk1-like MAPK, Lf pmk1 in the development of Lecanicillium fungicola (formerly Verticillium fungicola) infection on the cultivated mushroom Agaricus bisporus. Lf pmk1 was isolated using a degenerate PCR-based approach and was shown to be present in a single copy by Southern blot analysis. Quantitative RT-PCR showed the transcript to be fivefold upregulated in cap lesions compared with pure culture. Agrobacterium-mediated targeted disruption was used to delete a central portion of the Lf pmk1 gene. The resulting mutants showed normal symptom development as assessed by A. bisporus mushroom cap assays, sporulation patterns were normal and there were no apparent changes in overall growth rates. Our results indicate that, unlike the situation in fungal-plant pathogens, the pmk1-like MAPK pathway is not required for virulence in the fungal-fungal interaction between the L. fungicola pathogen and A. bisporus host. This observation may be of wider significance in other fungal-fungal and/or fungal-invertebrate interactions.

  9. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Joel Walls; M.T. Taner; Gary Mavko; Jack Dvorkin

    2002-04-01

    Wave-induced variations of pore pressure in a partially-saturated reservoir result in oscillatory liquid flow. The viscous losses during this flow are responsible for wave attenuation. The same viscous effects determine the changes in the dynamic bulk modulus of the system versus frequency. These changes are necessarily linked to attenuation via the causality condition. We analytically quantify the frequency dependence of the bulk modulus of a partially saturated rock by assuming that saturation is patchy and then link these changes to the inverse quality factor. As a result, the P-wave attenuation is quantitatively linked to saturation and thus can serve as a saturation indicator.

  10. Integrated Microfluidic Variable Optical Attenuator

    Science.gov (United States)

    2005-11-28

    indices , the optical output power is gradually attenuated. We obtain a maximum attenuation of 28 dB when the fluid refractive index changes from 1.557 to...Electron. 23, pp. 1348-1354 (2005). 14. J. M. Ruano, V. Benoit, J. S. Aitchison , and J. M. Cooper, “Flame hydrolysis deposition of glass on silicon for...different refractive indices flowing in a microfluidic channel as the cladding for a segment of straight optical waveguide. Recently, the integration of

  11. The Impact of Genotyping-by-Sequencing Pipelines on SNP Discovery and Identification of Markers Associated with Verticillium Wilt Resistance in Autotetraploid Alfalfa (Medicago sativa L.).

    Science.gov (United States)

    Yu, Long-Xi; Zheng, Ping; Bhamidimarri, Suresh; Liu, Xiang-Ping; Main, Dorie

    2017-01-01

    Verticillium wilt (VW) of alfalfa is a soilborne disease causing severe yield loss in alfalfa. To identify molecular markers associated with VW resistance, we used an integrated framework of genome-wide association study (GWAS) with high-throughput genotyping by sequencing (GBS) to identify loci associated with VW resistance in an F1 full-sib alfalfa population. Phenotyping was performed using manual inoculation of the pathogen to cloned plants of each individual and disease severity was scored using a standard scale. Genotyping was done by GBS, followed by genotype calling using three bioinformatics pipelines including the TASSEL-GBS pipeline (TASSEL), the Universal Network Enabled Analysis Kit (UNEAK), and the haplotype-based FreeBayes pipeline (FreeBayes). The resulting numbers of SNPs, marker density, minor allele frequency (MAF) and heterozygosity were compared among the pipelines. The TASSEL pipeline generated more markers with the highest density and MAF, whereas the highest heterozygosity was obtained by the UNEAK pipeline. The FreeBayes pipeline generated tetraploid genotypes, with the least number of markers. SNP markers generated from each pipeline were used independently for marker-trait association. Markers significantly associated with VW resistance identified by each pipeline were compared. Similar marker loci were found on chromosomes 5, 6, and 7, whereas different loci on chromosome 1, 2, 3, and 4 were identified by different pipelines. Most significant markers were located on chromosome 6 and they were identified by all three pipelines. Of those identified, several loci were linked to known genes whose functions are involved in the plants' resistance to pathogens. Further investigation on these loci and their linked genes would provide insight into understanding molecular mechanisms of VW resistance in alfalfa. Functional markers closely linked to the resistance loci would be useful for MAS to improve alfalfa cultivars with enhanced resistance to

  12. A cupin domain-containing protein with a quercetinase activity (VdQase) regulates Verticillium dahliae's pathogenicity and contributes to counteracting host defenses.

    Science.gov (United States)

    El Hadrami, Abdelbasset; Islam, Md Rashidul; Adam, Lorne R; Daayf, Fouad

    2015-01-01

    We previously identified rutin as part of potato root responses to its pathogen Verticillium dahliae. Rutin was directly toxic to the pathogen at doses greater than 160 μM, a threshold below which many V. dahliae pathogenicity-related genes were up-regulated. We identified and characterized a cupin domain-containing protein (VdQase) with a dioxygenase activity and a potential role in V. dahliae-potato interactions. The pathogenicity of VdQase knock-out mutants generated through Agrobacterium tumefasciens-mediated transformation was significantly reduced on susceptible potato cultivar Kennebec compared to wild type isolates. Fluorescence microscopy revealed a higher accumulation of flavonols in the stems of infected potatoes and a higher concentration of rutin in the leaves in response to the VdQase mutants as compared to wild type isolates. This, along with the HPLC characterization of high residual and non-utilized quercetin in presence of the knockout mutants, indicates the involvement of VdQase in the catabolism of quercetin and possibly other flavonols in planta. Quantification of Salicylic and Jasmonic Acids (SA, JA) in response to the mutants vs. wild type isolates revealed involvement of VdQase in the interference with signaling, suggesting a role in pathogenicity. It is hypothesized that the by-product of dioxygenation 2-protocatechuoylphloroglucinolcarboxylic acid, after dissociating into phloroglucinol and protocatechuoyl moieties, becomes a starting point for benzoic acid and SA, thereby interfering with the JA pathway and affecting the interaction outcome. These events may be key factors for V. dahliae in countering potato defenses and becoming notorious in the rhizosphere.

  13. Transcription factor VdCmr1 is required for pigment production, protection from UV irradiation, and regulates expression of melanin biosynthetic genes in Verticillium dahliae.

    Science.gov (United States)

    Wang, Yonglin; Hu, Xiaoping; Fang, Yulin; Anchieta, Amy; Goldman, Polly H; Hernandez, Gustavo; Klosterman, Steven J

    2018-02-27

    Verticillium dahliae is a soilborne fungus that causes vascular wilt diseases on numerous plant species worldwide. The production of darkly melanized microsclerotia is crucial in the disease cycle of V. dahliae, as these structures allow for long-term survival in soil. Previously, transcriptomic and genomic analysis identified a cluster of genes in V. dahliae that encodes some dihydroxynaphthalene (DHN) melanin biosynthetic pathway homologues found in related fungi. In this study, we explored the roles of cluster-specific transcription factor VdCmr1, as well as two other genes within the cluster encoding a polyketide synthase (VdPKS1) and a laccase (VdLac1), enzymes at initial and endpoint steps in DHN melanin production. The results revealed that VdCmr1 and VdPKS1 are required for melanin production, but neither is required for microsclerotia production. None of the three genes were required for pathogenesis on tobacco and lettuce. Exposure of ΔVdCmr1 and wild-type strains to UV irradiation, or to high temperature (40 °C), revealed an approx. 50 % reduction of survival in the ΔVdCmr1 strain, relative to the wild-type strain, in response to either condition. Expression profiles revealed that expression of some melanin biosynthetic genes are in part dependent on VdCmr1. Combined data indicate VdCmr1 is a key regulator of melanin biosynthesis, and that via regulation of melanogenesis, VdCmr1 affects survival of V. dahliae in response to abiotic threats. We conclude with a model showing regulation of VdCmr1 by a high osmolarity glycerol response (Hog)-type MAP kinase pathway.

  14. A cupin domain-containing protein with a quercetinase activity (VdQase regulates Verticillium dahliae’s pathogenicity and contributes to counteracting host defenses

    Directory of Open Access Journals (Sweden)

    Abdel eElHadrami

    2015-06-01

    Full Text Available We previously identified rutin as part of potato root responses to its pathogen Verticillium dahliae. Rutin was directly toxic to the pathogen at doses greater than 160 μM, a threshold below which many V. dahliae pathogenicity-related genes were up-regulated. We identified and characterized a cupin domain-containing protein (VdQase with a dioxygenase activity and a potential role in V. dahliae-potato interactions. The pathogenicity of VdQase knock-out mutants generated through Agrobacterium tumefasciens-mediated transformation was significantly reduced on susceptible potato cultivar Kennebec compared to wild type isolates. Fluorescence microscopy revealed a higher accumulation of flavonols in the stems of infected potatoes and a higher concentration of rutin in the leaves in response to the VdQase mutants as compared to wild type isolates. This, along with the HPLC characterization of high residual and non-utilized quercetin in presence of the knockout mutants, indicates the involvement of VdQase in the catabolism of quercetin and possibly other flavonols in planta. Quantification of Salicylic and Jasmonic Acids (SA, JA in response to the mutants versus wild type isolates revealed involvement of VdQase in the interference with signaling, suggesting a role in pathogenicity. It is hypothesized that the by-product of dioxygenation 2-protocatechuoylphloroglucinolcarboxylic acid, after dissociating into phloroglucinol and protocatechuoyl moieties, becomes a starting point for benzoic acid and SA, thereby interfering with the JA pathway and affecting the interaction outcome. These events may be key factors for V. dahliae in countering potato defenses and becoming notorious in the rhizosphere.

  15. A New Synthetic Amphiploid (AADDAA between Gossypium hirsutum and G. arboreum Lays the Foundation for Transferring Resistances to Verticillium and Drought.

    Directory of Open Access Journals (Sweden)

    Yu Chen

    Full Text Available Gossypium arboreum, a cultivated cotton species (2n = 26, AA native to Asia, possesses invaluable characteristics unavailable in the tetraploid cultivated cotton gene pool, such as resistance to pests and diseases and tolerance to abiotic stresses. However, it is quite difficult to transfer favorable traits into Upland cotton through conventional methods due to the cross-incompatibility of G. hirsutum (2n = 52, AADD and G. arboreum. Here, we improved an embryo rescue technique to overcome the cross-incompatibility between these two parents for transferring favorable genes from G. arboreum into G. hirsutum. Our results indicate that MSB2K supplemented with 0.5 mg l(-1 kinetin and 250 mg(-1 casein hydrolysate is an efficient initial medium for rescuing early (3 d after pollination hybrid embryos. Eight putative hybrids were successfully obtained, which were further verified and characterized by cytology, molecular markers and morphological analysis. The putative hybrids were subsequently treated with different concentrations of colchicine solution to double their chromosomes. The results demonstrate that four putative hybrid plants were successfully chromosome-doubled by treatment with 0.1% colchicine for 24 h and become amphiploid, which were confirmed by cytological observation, self-fertilization and backcrossing. Preliminary assessments of resistance at seedling stage indicate that the synthetic amphiploid showed highly resistant to Verticillium and drought. The synthetic amphiploid between G. hirsutum × G. arboreum would lay the foundation for developing G. arboreum-introgressed lines with the uniform genetic background of G. hirsutum acc TM-1, which would greatly enhance and simplify the mining, isolation, characterization, cloning and use of G. arboreum-specific desirable genes in future cotton breeding programs.

  16. The bacterial lipopeptide iturins induce Verticillium dahliae cell death by affecting fungal signalling pathways and mediate plant defence responses involved in pathogen-associated molecular pattern-triggered immunity.

    Science.gov (United States)

    Han, Qin; Wu, Fengli; Wang, Xiaonan; Qi, Hong; Shi, Liang; Ren, Ang; Liu, Qinghai; Zhao, Mingwen; Tang, Canming

    2015-04-01

    Verticillium wilt in cotton caused by Verticillium dahliae is one of the most serious plant diseases worldwide. Because no known fungicides or cotton cultivars provide sufficient protection against this pathogen, V. dahliae causes major crop yield losses. Here, an isolated cotton endophytic bacterium, designated Bacillus amyloliquefaciens 41B-1, exhibited greater than 50% biocontrol efficacy against V. dahliae in cotton plants under greenhouse conditions. Through high-performance liquid chromatography and mass analysis of the filtrate, we found that the antifungal compounds present in the strain 41B-1 culture filtrate were a series of isoforms of iturins. The purified iturins suppressed V. dahliae microsclerotial germination in the absence or presence of cotton. Treatment with the iturins induced reactive oxygen species bursts, Hog1 mitogen-activated protein kinase (MAPK) activation and defects in cell wall integrity. The oxidative stress response and high-osmolarity glycerol pathway contribute to iturins resistance in V. dahliae. In contrast, the Slt2 MAPK pathway may be involved in iturins sensitivity in this fungus. In addition to antagonism, iturins could induce plant defence responses as activators and mediate pathogen-associated molecular pattern-triggered immunity. These findings suggest that iturins may affect fungal signalling pathways and mediate plant defence responses against V. dahliae. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  17. Attenuation in Superconducting Circular Waveguides

    Directory of Open Access Journals (Sweden)

    K. H. Yeap

    2016-09-01

    Full Text Available We present an analysis on wave propagation in superconducting circular waveguides. In order to account for the presence of quasiparticles in the intragap states of a superconductor, we employ the characteristic equation derived from the extended Mattis-Bardeen theory to compute the values of the complex conductivity. To calculate the attenuation in a circular waveguide, the tangential fields at the boundary of the wall are first matched with the electrical properties (which includes the complex conductivity of the wall material. The matching of fields with the electrical properties results in a set of transcendental equations which is able to accurately describe the propagation constant of the fields. Our results show that although the attenuation in the superconducting waveguide above cutoff (but below the gap frequency is finite, it is considerably lower than that in a normal waveguide. Above the gap frequency, however, the attenuation in the superconducting waveguide increases sharply. The attenuation eventually surpasses that in a normal waveguide. As frequency increases above the gap frequency, Cooper pairs break into quasiparticles. Hence, we attribute the sharp rise in attenuation to the increase in random collision of the quasiparticles with the lattice structure.

  18. Attenuation in silica-based optical fibers

    DEFF Research Database (Denmark)

    Wandel, Marie Emilie

    2006-01-01

    In this thesis on attenuation in silica based optical fibers results within three main topics are reported. Spectral attenuation measurements on transmission fibers are performed in the wide wavelength range 290 nm – 1700 nm. The measured spectral attenuation is analyzed with special emphasis...... on absorption peaks in order to investigate the cause of an unusual high attenuation in a series of transmission fibers. Strong indications point to Ni2+ in octahedral coordination as being the cause of the high attenuation. The attenuation of fibers having a high core refractive index is analyzed and the cause...... of the high attenuation measured in such fibers is described as being due to scattering of light on fluctuations of the core diameter. A novel semi-empirical model for predicting the attenuation of high index fibers is presented. The model is shown to be able to predict the attenuation of high index fibers...

  19. Seismic attenuation imaging with causality

    NARCIS (Netherlands)

    Hak, B.; Mulder, W.A.

    2010-01-01

    Seismic data enable imaging of the Earth, not only of velocity and density but also of attenuation contrasts. Unfortunately, the Born approximation of the constant-density visco-acoustic wave equation, which can serve as a forward modelling operator related to seismic migration, exhibits an

  20. Josephson tunnel junction microwave attenuator

    DEFF Research Database (Denmark)

    Koshelets, V. P.; Shitov, S. V.; Shchukin, A. V.

    1993-01-01

    A new element for superconducting electronic circuitry-a variable attenuator-has been proposed, designed, and successfully tested. The principle of operation is based on the change in the microwave impedance of a superconductor-insulator-superconductor (SIS) Josephson tunnel junction when dc bias...

  1. Compact plasmonic variable optical attenuator

    DEFF Research Database (Denmark)

    Leosson, Kristjan; Rosenzveig, Tiberiu; Hermannsson, Pétur Gordon

    2008-01-01

    We demonstrate plasmonic nanowire-based thermo-optic variable optical attenuators operating in the 1525-1625 nm wavelength range. The devices have a footprint as low as 1 mm, extinction ratio exceeding 40 dB, driving voltage below 3 V, and full modulation bandwidth of 1 kHz. The polarization...

  2. Flagella overexpression attenuates Salmonella pathogenesis.

    Directory of Open Access Journals (Sweden)

    Xinghong Yang

    Full Text Available Flagella are cell surface appendages involved in a number of bacterial behaviors, such as motility, biofilm formation, and chemotaxis. Despite these important functions, flagella can pose a liability to a bacterium when serving as potent immunogens resulting in the stimulation of the innate and adaptive immune systems. Previous work showing appendage overexpression, referred to as attenuating gene expression (AGE, was found to enfeeble wild-type Salmonella. Thus, this approach was adapted to discern whether flagella overexpression could induce similar attenuation. To test its feasibility, flagellar filament subunit FliC and flagellar regulon master regulator FlhDC were overexpressed in Salmonella enterica serovar Typhimurium wild-type strain H71. The results show that the expression of either FliC or FlhDC alone, and co-expression of the two, significantly attenuates Salmonella. The flagellated bacilli were unable to replicate within macrophages and thus were not lethal to mice. In-depth investigation suggests that flagellum-mediated AGE was due to the disruptive effects of flagella on the bacterial membrane, resulting in heightened susceptibilities to hydrogen peroxide and bile. Furthermore, flagellum-attenuated Salmonella elicited elevated immune responses to Salmonella presumably via FliC's adjuvant effect and conferred robust protection against wild-type Salmonella challenge.

  3. Flagella Overexpression Attenuates Salmonella Pathogenesis

    Science.gov (United States)

    Yang, Xinghong; Thornburg, Theresa; Suo, Zhiyong; Jun, SangMu; Robison, Amanda; Li, Jinquan; Lim, Timothy; Cao, Ling; Hoyt, Teri; Avci, Recep; Pascual, David W.

    2012-01-01

    Flagella are cell surface appendages involved in a number of bacterial behaviors, such as motility, biofilm formation, and chemotaxis. Despite these important functions, flagella can pose a liability to a bacterium when serving as potent immunogens resulting in the stimulation of the innate and adaptive immune systems. Previous work showing appendage overexpression, referred to as attenuating gene expression (AGE), was found to enfeeble wild-type Salmonella. Thus, this approach was adapted to discern whether flagella overexpression could induce similar attenuation. To test its feasibility, flagellar filament subunit FliC and flagellar regulon master regulator FlhDC were overexpressed in Salmonella enterica serovar Typhimurium wild-type strain H71. The results show that the expression of either FliC or FlhDC alone, and co-expression of the two, significantly attenuates Salmonella. The flagellated bacilli were unable to replicate within macrophages and thus were not lethal to mice. In-depth investigation suggests that flagellum-mediated AGE was due to the disruptive effects of flagella on the bacterial membrane, resulting in heightened susceptibilities to hydrogen peroxide and bile. Furthermore, flagellum-attenuated Salmonella elicited elevated immune responses to Salmonella presumably via FliC’s adjuvant effect and conferred robust protection against wild-type Salmonella challenge. PMID:23056473

  4. An ethylene response-related factor, GbERF1-like, from Gossypium barbadense improves resistance to Verticillium dahliae via activating lignin synthesis.

    Science.gov (United States)

    Guo, Weifeng; Jin, Li; Miao, Yuhuan; He, Xin; Hu, Qin; Guo, Kai; Zhu, Longfu; Zhang, Xianlong

    2016-06-01

    An ethylene response-related factor, GbERF1-like, from Gossypium barbadense cv. '7124' involved in the defence response to Verticillium dahliae was characterized. GbERF1-like transcripts present ubiquitously in various tissues, with higher accumulation in flower organs. GbERF1-like was also responsive to defence-related phytohormones and V. dahliae infection. The downregulation of GbERF1-like increased the susceptibility of cotton plants to V. dahliae infection, while overexpression of this gene improved disease resistance in both cotton and Arabidopsis, coupled with activation of the pathogenesis-related proteins. Further analysis revealed that genes involved in lignin synthesis, such as PAL, C4H, C3H, HCT, CCoAOMT, CCR and F5H, showed higher expression levels in the overexpressing cotton and Arabidopsis lines and lower expression levels in the RNAi cotton lines. The expression levels of these genes increased obviously when the GbERF1-like-overexpressing plants were inoculated with V. dahliae. Meanwhile, significant differences in the content of whole lignin could be found in the stems of transgenic and wild-type plants after inoculation with V. dahliae, as revealed by metabolic and histochemical analysis. More lignin could be detected in GbERF1-like-overexpressing cotton and Arabidopsis but less in GbERF1-like-silencing cotton compared with wild-type plants. The ratio of S and G monomers in GbERF1-like-overexpressing cotton and Arabidopsis increased significantly after infection by V. dahliae. Moreover, our results showed that the promoters of GhHCT1 and AtPAL3 could be transactivated by GbERF1-like in vivo based on yeast one-hybrid assays and dual-luciferase reporter assays. Knockdown of GhHCT1 in GbERF1-like over-expressing cotton decreases resistance to V. dahliae. Collectively, our results suggest that GbERF1-like acts as a positive regulator in lignin synthesis and contributes substantially to resistance to V. dahliae in plants.

  5. Lung attenuation measurements in healthy young adults.

    NARCIS (Netherlands)

    Smit, H.J.M.; Golding, R.P.; Schramel, F.M.N.H.; Devillé, W.L.; Manoliu, R.A.; Postmus, P.E.

    2003-01-01

    Background: High-resolution computed tomography (HRCT) attenuation measurements may be more sensitive in finding early emphysematous changes in relatively young subjects than lung function measurements. Objectives: To define lung attenuation parameters in smokers and never-smokers. Methods: A

  6. Inner Core Anisotropy in Attenuation

    Science.gov (United States)

    Yu, W.; Wen, L.

    2004-12-01

    It is now well established that the compressional velocity in the Earth's inner core varies in both direction and geographic location. The compressional waves travel faster along the polar directions than along the equatorial directions. Such polar-equatorial difference is interpreted as a result of inner core anisotropy in velocity (with a magnitude of about 3%) and such anisotropy appears to be stronger in the ``western hemisphere" (180oW -40oE) than in the ``eastern hemisphere" (40oE-180oE). Along the equatorial paths, the compressional velocity also exhibits a hemispheric pattern with the eastern hemisphere being about 1% higher than the western hemisphere. Possible explanations for the causes of the velocity in anisotropy and the hemispheric difference in velocity along the equatorial paths include different geometric inclusions of melt or different alignments of iron crystals which are known to be anisotropic in velocities. Here, we report an observation of ubiquitous correlation between small (large) amplitude and fast (slow) travel time of the PKIKP waves sampling the top 300 km of the inner core. We study this correlation by jointly analyzing the differential travel times and amplitude ratios of the PKiKP-PKIKP and the PKPbc-PKIKP phases recorded by the Global Seismographic Network (1990-2001), various regional seismic networks (BANJO, BLSP, FREESIA, GEOFON, GEOSCOPE, Kazakhstan, Kyrgyz, MEDNET, and OHP), and several PASSCAL Networks deployed in Alaska and Antarctica (XE: 1999-2001, XF: 1995-1996, and YI: 1998-1999). Our dataset consists of 310 PKiKP-PKIKP and 240 PKPbc-PKIKP phases, selected from a total of more than 16,000 observations. PKIKP waves exhibit relatively smaller amplitudes for those sampling the eastern hemisphere along the equatorial paths and even smaller amplitudes for those sampling the polar paths in the western hemisphere. One simple explanation for the velocity-attenuation relation is that the inner core is anisotropic in attenuation

  7. ENHANCEMENTS TO NATURAL ATTENUATION: SELECTED CASE STUDIES

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K; W. H. Albright, W; E. S. Becvar, E; C. H. Benson, C; T. O. Early, T; E. Hood, E; P. M. Jardine, P; M. Lorah, M; E. Majche, E; D. Major, D; W. J. Waugh, W; G. Wein, G; O. R. West, O

    2007-05-15

    In 2003 the US Department of Energy (DOE) embarked on a project to explore an innovative approach to remediation of subsurface contaminant plumes that focused on introducing mechanisms for augmenting natural attenuation to achieve site closure. Termed enhanced attenuation (EA), this approach has drawn its inspiration from the concept of monitored natural attenuation (MNA).

  8. A fully integrated optofluidic attenuator

    Science.gov (United States)

    Müller, Philipp; Kloss, Anton; Liebetraut, Peter; Mönch, Wolfgang; Zappe, Hans

    2011-12-01

    A fast and reliable, fully integrated optofluidic optical attenuator is demonstrated. The concept employs only liquid and thus has no mechanically moving parts. Transparent and opaque aqueous liquid droplets are displaced using an on-chip electrowetting actuator and, due to the flexibility in the choice of liquids, various transmission spectra can be defined. The microfluidic attenuator system is fabricated using wafer-level bonding and dry film resists resulting in an ultra-compact (11×23×1.6 mm3) device requiring no external components for operation. The measured dynamic range of optical transmission is up to 47 dB, while the response times are below 100 ms for a 2 mm input beam. Using a novel double-actuator configuration, actuation speeds of the liquids of up to 39 mm s-1 were measured.

  9. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Joel Walls; M.T. Taner; Gary Mavko; Jack Dvorkin

    2002-01-01

    In Section 1 of this first report we will describe the work we are doing to collect and analyze rock physics data for the purpose of modeling seismic attenuation from other measurable quantities such as porosity, water saturation, clay content and net stress. This work and other empirical methods to be presented later, will form the basis for ''Q pseudo-well modeling'' that is a key part of this project. In Section 2 of this report, we will show the fundamentals of a new method to extract Q, dispersion, and attenuation from field seismic data. The method is called Gabor-Morlet time-frequency decomposition. This technique has a number of advantages including greater stability and better time resolution than spectral ratio methods.

  10. SOUND ATTENUATION IN FERROELECTRIC SOLIDS

    OpenAIRE

    Naithani, U.; Semwal, B.

    1981-01-01

    An expression for the sound-attenuation constant in doped displacive ferroelectrics, in the presence of an external electric field, is obtained by using the double-time thermal- Green's -functions technique. The mass and force constant changes between the impurity and the host lattice atoms are taken into account in the Silverman Hamiltonian augmented with higher -order anharmonic and electric-moment terms. The defect-dependent, electric- field-dependent, and anharmonic contributions to the a...

  11. Flagella Overexpression Attenuates Salmonella Pathogenesis

    OpenAIRE

    Xinghong Yang; Theresa Thornburg; Zhiyong Suo; SangMu Jun; Amanda Robison; Jinquan Li; Timothy Lim; Ling Cao; Teri Hoyt; Recep Avci; Pascual, David W.

    2012-01-01

    Flagella are cell surface appendages involved in a number of bacterial behaviors, such as motility, biofilm formation, and chemotaxis. Despite these important functions, flagella can pose a liability to a bacterium when serving as potent immunogens resulting in the stimulation of the innate and adaptive immune systems. Previous work showing appendage overexpression, referred to as attenuating gene expression (AGE), was found to enfeeble wild-type Salmonella. Thus, this approach was adapted to...

  12. Leaf mineral composition of grafted eggplant grown in soil infested with Verticillium and root-knot nematodes Composição mineral de folhas de berinjela enxertada e cultivada em solos infestados com Verticillium e nematóide-das-galhas

    Directory of Open Access Journals (Sweden)

    Sebahattin Çürük

    2010-08-01

    Full Text Available The objective of this work was to determine differences in leaf mineral composition between ungrafted and grafted onto (Solanum torvum eggplant (Solanum melongena, cultivars 'Faselis' and 'Pala', grown in a soil infested with Verticillium dahliae and Meloidogyne incognita, or in a noninfested soil. Grafting increased leaf P and Mn concentrations, and decreased N concentrations, in both soils. Grafting also enhanced leaf Ca concentration of 'Pala', but it did not affect that of 'Faselis' depending on the cropping year. Leaf Mg concentration of grafted plants in infested soil was lower than that of ungrafted ones in noninfested soil. Results showed that, under the same fertilization program, the grafted 'Faselis' plants used the nutrients more efficiently than the 'Pala' ones. Use of S. torvum as a rootstock for 'Faselis' resulted in an effective protection against multiple pathogen infestation. Fertilization may be necessary when grafted 'Faselis' plants are grown in a soil infested with the pathogens, since grafting and infestation generally decrease leaf N, Mg, Ca and Fe concentrations, either by reducing the nutrient concentrations directly or by increasing leaf Mn concentration.O objetivo deste trabalho foi determinar as diferenças de composição mineral das folhas entre as cultivares de berinjela (Solanum melongena, 'Faselis' e 'Pala', enxertadas em Solanum torvum ou não enxertadas, e plantadas em solos infestados ou não com Verticillium dahliae e Meloidogyne incognita. A enxertia aumentou as concentrações de P e Mn nas folhas e diminuiu as de nitrogênio, em ambos os solos. A enxertia também aumentou a concentração de Ca foliar em 'Pala', mas não em 'Faselis', conforme o ano agrícola. A concentração de Mg foliar, em plantas enxertadas em solo infestado, foi menor que a de plantas não enxertadas em solo não infestado. Com um mesmo programa de adubação, as plantas enxertadas de 'Faselis' utilizaram os nutrientes de maneira

  13. Physical characteristics and attenuation of foam earplugs

    Energy Technology Data Exchange (ETDEWEB)

    Smith, C.R.; Broughton, R.M.; Wilmoth, J.N.; Borton, T.E.; Mozo, B.T.

    1982-01-01

    The purpose of this investigation was twofold: (1) to determine the physical characteristics of five types of foam earplugs; and (2) to relate their physical characteristics to attenuation of noise. The results indicate that: (1) all commercial polymer foam earplugs have similar physical properties, (2) frequency is the single most important variable in determining attenuation of commercial foam earplugs, (3) all earplugs evaluated provided essentially the same attenuation at frequencies >500 Hz. One non-commercial earplug provided significantly more attenuation at 125 Hz than the other earplugs. This non-commercial experimental plug has significantly different physical and chemical properties. No other consistent effects of physical properties on attenuation were found.

  14. Island cotton Enhanced Disease Susceptibility 1 gene encoding a lipase-like protein plays a crucial role in response to Verticillium dahliae by regulating the SA level and H2O2 accumulation

    Directory of Open Access Journals (Sweden)

    Yan Zhang

    2016-12-01

    Full Text Available Cotton is one of the most economically important crops, but most cultivated varieties lack adequate innate immunity or resistance to Verticillium wilt. This results in serious losses to both yield and fiber quality. To identify the genetic resources for innate immunity and understand the pathways for pathogen defenses in this crop, here we focus on orthologs of the central Arabidopsis thaliana defense regulator Enhanced Disease Susceptibility 1 (EDS1. The full-length cDNA of GbEDS1 was obtained by screening the full-length cDNA library of Gossypium barbadense combining with RACE strategy. Its open reading frame is 1848 bp long, encoding 615 amino acid residues. Sequence analysis showed that GbEDS1 contains a conserved N-terminal lipase domain and an EDS1-specific KNEDT motif. Expression profiling indicated that the gene is induced by Verticillium dahliae as well as salicylic acid (SA treatment. Subcellular localization assays revealed that GbEDS1 is located in the cell cytoplasm and nucleus. Overexpression of GbEDS1 in Arabidopsis dramatically up-regulated SA and H2O2 production, resulting in enhanced disease resistance to V. dahliae. Silencing of GbEDS1 in G. barbadense significantly decreased SA and H2O2 acumulation, leading to the cotton more susceptibility. Moreover, combining the gene expression results from transgenic Arabidopsis and silenced-GbEDS1 cotton, it indicated that GbEDS1 could activate GbNDR1 and GbBAK1 expression. These findings not only broaden our knowledge about the biological role of GbEDS1, but also provide new insights into the defense mechanisms of GbEDS1 against V. dahliae in cotton.

  15. Method for Estimating Total Attenuation from a Spatial Map of Attenuation Slope for Quantitative Ultrasound Imaging

    OpenAIRE

    Pawlicki, Alexander D.; O'Brien, William D.

    2013-01-01

    Estimating total ultrasound attenuation from backscatter data is essential in the field of quantitative ultrasound (QUS) because of the need to compensate for attenuation when estimating the backscatter coefficient and QUS parameters. This work uses a reference phantom method of attenuation estimation to create a spatial map of attenuation slope (AS) from backscatter radio-frequency (RF) data of three phantoms and a rat mammary adenocarcinoma tumor (MAT). The attenuation maps show changes in ...

  16. Method for estimating total attenuation from a spatial map of attenuation slope for quantitative ultrasound imaging.

    Science.gov (United States)

    Pawlicki, Alexander D; O'Brien, William D

    2013-04-01

    Estimating total ultrasound attenuation from backscatter data is essential in the field of quantitative ultrasound (QUS) because of the need to compensate for attenuation when estimating the backscatter coefficient and QUS parameters. This work uses a reference phantom method of attenuation estimation to create a spatial map of attenuation slope (AS) from backscatter radio-frequency (RF) data of three phantoms and a rat mammary adenocarcinoma tumor (MAT). The attenuation maps show changes in attenuation between different regions of the phantoms and the MAT tumor. Analyses of the attenuation maps of the phantoms suggest that the AS estimates are in good quantitative agreement with the known values for the phantoms. Furthermore, estimates of total attenuation from the attenuation maps are likewise in good quantitative agreement with known values.

  17. Rg propagation: Scatter versus Attenuation

    Science.gov (United States)

    Cleveland, M.; Phillips, W. S.; MacCarthy, J.

    2016-12-01

    At near local distances, the Rg seismic phase is often the largest seismic arrival for shallow sources. While Rg is classically defined for the period range of 8-12 s, we use the term generically to refer to short-period observations of Rayleigh waves from shallow sources [e.g. Langston, 1987; Bonner and Russell, 2013]. There is significant interest in using Rg as a basis for seismic discrimination and magnitude (e.g. Bonner and Russell, 2013). However, the propagation of this phase is poorly understood. At Nevada National Security Site, while Rg is well observed near the source, it quickly disappears at greater distances. This observation raises the fundamental question of how much of the Rg energy is simply attenuating versus scattering into other seismic phases. Understanding this is critical to interpreting not only the observed Rg seismic energy, but also the possible enrichment of other seismic phases resulting from Rg scattering. In this study, we use waveform data from the Bighorn Arch Seismic Experiment (BASE) and Source Physics Experiment (SPE) to investigate Rg propagation, looking to identify how much energy from the phase attenuates with distance and how much scatters into other seismic phases.

  18. Chlorine signal attenuation in concrete.

    Science.gov (United States)

    Naqvi, A A; Maslehuddin, M; ur-Rehman, Khateeb; Al-Amoudi, O S B

    2015-11-01

    The intensity of prompt gamma-ray was measured at various depths from chlorine-contaminated silica fume (SF) concrete slab concrete specimens using portable neutron generator-based prompt gamma-ray setup. The intensity of 6.11MeV chloride gamma-rays was measured from the chloride contaminated slab at distance of 15.25, 20.25, 25.25, 30.25 and 35.25cm from neutron target in a SF cement concrete slab specimens. Due to attenuation of thermal neutron flux and emitted gamma-ray intensity in SF cement concrete at various depths, the measured intensity of chlorine gamma-rays decreases non-linearly with increasing depth in concrete. A good agreement was noted between the experimental results and the results of Monte Carlo simulation. This study has provided useful experimental data for evaluating the chloride contamination in the SF concrete utilizing gamma-ray attenuation method. Copyright © 2015 Elsevier Ltd. All rights reserved.

  19. SEISMIC ATTENUATION FOR RESERVOIR CHARACTERIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Joel Walls; M.T. Taner; Naum Derzhi; Gary Mavko; Jack Dvorkin

    2003-12-01

    We have developed and tested technology for a new type of direct hydrocarbon detection. The method uses inelastic rock properties to greatly enhance the sensitivity of surface seismic methods to the presence of oil and gas saturation. These methods include use of energy absorption, dispersion, and attenuation (Q) along with traditional seismic attributes like velocity, impedance, and AVO. Our approach is to combine three elements: (1) a synthesis of the latest rock physics understanding of how rock inelasticity is related to rock type, pore fluid types, and pore microstructure, (2) synthetic seismic modeling that will help identify the relative contributions of scattering and intrinsic inelasticity to apparent Q attributes, and (3) robust algorithms that extract relative wave attenuation attributes from seismic data. This project provides: (1) Additional petrophysical insight from acquired data; (2) Increased understanding of rock and fluid properties; (3) New techniques to measure reservoir properties that are not currently available; and (4) Provide tools to more accurately describe the reservoir and predict oil location and volumes. These methodologies will improve the industry's ability to predict and quantify oil and gas saturation distribution, and to apply this information through geologic models to enhance reservoir simulation. We have applied for two separate patents relating to work that was completed as part of this project.

  20. Breast imaging using waveform attenuation tomography

    Science.gov (United States)

    Li, Cuiping; Sandhu, Gursharan Y.; Boone, Michael; Duric, Neb

    2017-03-01

    Ex vivo studies using our ultrasound waveform attenuation algorithm have shown promising results for detection and characterization of lesions of different types. Our preliminary in vivo study shows that the waveform attenuation image has much higher resolution and can better delineate breast lesions boundaries than the corresponding ray-based attenuation image. In this study, we preprocessed our time domain waveforms acquired with a ring array and explored the directional transducer beam pattern to better match calculated wave fields with respect to the acquired wave fields. We have applied waveform attenuation to in vivo data and compared the resulting waveform attenuation images with the ray-based counterparts to assess the resolution and accuracy of the waveform attenuation reconstruction.

  1. Wave attenuation charcteristics of tethered float system

    Digital Repository Service at National Institute of Oceanography (India)

    Vethamony, P.

    parameters. The effect of drag on wave attenuation is studied for varying drag coefficient values. Theoretical results are compared with experimental values and it is found that theory overestimates wave attenuation which may probably be due to various... 15 and 16, respectively. These figures show that theory overestimates the wave attenuation and this may probably be due to various linearisations involved in the theoretical formulation. Experimental results are also not very accurate because...

  2. Lung attenuation measurements in healthy young adults.

    OpenAIRE

    Smit, H.J.M.; Golding, R.P.; Schramel, F.M.N.H.; Devillé, W.L.; Manoliu, R.A.; Postmus, P. E.

    2003-01-01

    Background: High-resolution computed tomography (HRCT) attenuation measurements may be more sensitive in finding early emphysematous changes in relatively young subjects than lung function measurements. Objectives: To define lung attenuation parameters in smokers and never-smokers. Methods: A prospective comparative study in a university hospital setting was designed with 20 healthy smoking and 20 nonsmoking volunteers. Attenuation measurements on spirometrically controlled HRCT at three leve...

  3. Noiseless attenuation using an optical parametric amplifier

    Science.gov (United States)

    Brewster, R. A.; Nodurft, I. C.; Pittman, T. B.; Franson, J. D.

    2017-10-01

    The process of heralded noiseless amplification, and the inverse process of heralded noiseless attenuation, have potential applications in the context of quantum communications. Although several different physical implementations of heralded noiseless amplifiers have now been demonstrated, the research on heralded noiseless attenuators has been largely confined to a beam-splitter based approach. Here we show that an optical parametric amplifier (OPA), combined with appropriate heralding, can also serve as a heralded noiseless attenuator. The counterintuitive use of an optical amplifier as an attenuator is only possible due to the probabilistic nature of the device.

  4. Multiple attenuation using eigenvalue decomposition | Aigbedion ...

    African Journals Online (AJOL)

    Multiple reflections constitute one of the most troublesome forms of coherent noise in seismic exploration, especially in marine surveys. There are many approaches to attenuating or suppressing multiples, but none can remove all multiple reflections under all conditions. We have eveloped two new methods to attenuate ...

  5. ATTENUATION AND FLANKING TRANSMISSION IN LIGHTWEIGHT STRUCTURES

    DEFF Research Database (Denmark)

    Brunskog, Jonas; Lhomond, Alice; Ohlrich, Mogens

    2007-01-01

    In this paper the attenuation and flanking transmissions of impact noise in lightweight building structures is studied using a modal approach. The structural field is mainly analysed, putting the main attention to the parts being important in the modelling. The amount of attenuation produced...

  6. Precision Model for Microwave Rotary Vane Attenuator

    DEFF Research Database (Denmark)

    Guldbrandsen, Tom

    1979-01-01

    A model for a rotary vane attenuator is developed to describe the attenuator reflection and transmission coefficients in detail. All the parameters of the model can be measured in situ, i.e., without diassembling any part. The tranmission errors caused by internal reflections are calculated from...

  7. Attenuation coefficients for water quality trading.

    Science.gov (United States)

    Keller, Arturo A; Chen, Xiaoli; Fox, Jessica; Fulda, Matt; Dorsey, Rebecca; Seapy, Briana; Glenday, Julia; Bray, Erin

    2014-06-17

    Water quality trading has been proposed as a cost-effective approach for reducing nutrient loads through credit generation from agricultural or point source reductions sold to buyers facing costly options. We present a systematic approach to determine attenuation coefficients and their uncertainty. Using a process-based model, we determine attenuation with safety margins at many watersheds for total nitrogen (TN) and total phosphorus (TP) loads as they transport from point of load reduction to the credit buyer. TN and TP in-stream attenuation generally increases with decreasing mean river flow; smaller rivers in the modeled region of the Ohio River Basin had TN attenuation factors per km, including safety margins, of 0.19-1.6%, medium rivers of 0.14-1.2%, large rivers of 0.13-1.1%, and very large rivers of 0.04-0.42%. Attenuation in ditches transporting nutrients from farms to receiving rivers is 0.4%/km for TN, while for TP attenuation in ditches can be up to 2%/km. A 95 percentile safety margin of 30-40% for TN and 6-10% for TP, applied to the attenuation per km factors, was determined from the in-stream sensitivity of load reductions to watershed model parameters. For perspective, over 50 km a 1% per km factor would result in 50% attenuation = 2:1 trading ratio.

  8. Ultrasound fields in an attenuating medium

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Gandhi,, D; O'Brien,, W.D., Jr.

    1993-01-01

    of the rectangles and sums all contributions to arrive at the spatial impulse response for the aperture and field point. This approach makes it possible to model all transducer apertures, and the program can readily calculate the emitted, pulse-echo and continuous wave field. Attenuation is included by splitting...... it into a frequency dependent part and frequency independent part. The latter results in an attenuation factor that is multiplied onto the responses from the individual elements, and the frequency dependent part is handled by attenuating the basic one-dimensional pulse. The influence on ultrasound fields from......Ultrasound fields propagating in tissue will undergo changes in shape not only due to diffraction, but also due to the frequency dependent attenuation. Linear fields can be fairly well predicted for a non-attenuating medium like water by using the Tupholme-Stepanishen method for calculating...

  9. Transport and attenuation of radiations

    CERN Document Server

    Nimal, J C

    2003-01-01

    This article treats of the calculation methods used for the dimensioning of the protections against radiations. The method consists in determining for a given point the flux of particles coming from a source at a given time. A strong attenuation (of about some few mu Sv.h sup - sup 1) is in general expected between the source and the areas accessible to the personnel or the public. The calculation has to take into account a huge number of radiation-matter interactions and to solve the integral-differential transport equation which links the particles flux to the source. Several methods exist from the simplified physical model with numerical developments to the more or less precise resolution of the transport equation. These methods allows also the calculation of the uncertainties of equivalent dose rates, heat sources, structure damages using the data covariances (efficient cross-sections, modeling, etc..): 1 - transport equation; 2 - Monte-Carlo method; 3 - semi-numerical methods S sub N; 4 - methods based o...

  10. Attenuation caused by infrequently updated covariates in survival analysis

    DEFF Research Database (Denmark)

    Andersen, Per Kragh; Liestøl, Knut

    2003-01-01

    Attenuation; Cox regression model; Measurement errors; Survival analysis; Time-dependent covariates......Attenuation; Cox regression model; Measurement errors; Survival analysis; Time-dependent covariates...

  11. Ação antagônica e de metabólitos bioativos de Trichoderma spp. contra os patógenos Sclerotium rolfsii e Verticillium dahliae

    Directory of Open Access Journals (Sweden)

    Carolina Oliveira Isaias

    2014-03-01

    Full Text Available O efeito antagônico exercido por fungos do gênero Trichoderma foi avaliado contra os fitopatógenos Sclerotium rolfsii e Verticillium dahliae, isolados de áster ornamental e morangueiro, respectivamente. Utilizaram-se 20 isolados do antagonista, pertencentes às espécies T. asperellum, T. hamatum, T. harzianum, T. koningiopsis, T. spirale e Trichoderma sp. O antagonismo foi verificado por meio de testes de culturas pareadas e produção de metabólitos bioativos pelo método de sobreposição de placas. A maioria dos isolados exibiu efeito inibitório sobre o crescimento micelial de S. rolfsii e V. dahliae quando comparado com as testemunhas. Excetuando-se os testes de produção de metabólitos não-voláteis, verificou-se maior ação inibitória contra V. dahliae. Mesmo os metabólitos não-voláteis termoestáveis apresentaram efeito inibitório contra ambos os patógenos testados, mostrando que os metabólitos secundários do antagonista exercem efeito significativo sobre essas espécies patogênicas.

  12. Seismic attenuation system for a nuclear reactor

    Energy Technology Data Exchange (ETDEWEB)

    Liszkai, Tamas; Cadell, Seth

    2018-01-30

    A system for attenuating seismic forces includes a reactor pressure vessel containing nuclear fuel and a containment vessel that houses the reactor pressure vessel. Both the reactor pressure vessel and the containment vessel include a bottom head. Additionally, the system includes a base support to contact a support surface on which the containment vessel is positioned in a substantially vertical orientation. An attenuation device is located between the bottom head of the reactor pressure vessel and the bottom head of the containment vessel. Seismic forces that travel from the base support to the reactor pressure vessel via the containment vessel are attenuated by the attenuation device in a direction that is substantially lateral to the vertical orientation of the containment vessel.

  13. Electron Effective-Attenuation-Length Database

    Science.gov (United States)

    SRD 82 NIST Electron Effective-Attenuation-Length Database (PC database, no charge)   This database provides values of electron effective attenuation lengths (EALs) in solid elements and compounds at selected electron energies between 50 eV and 2,000 eV. The database was designed mainly to provide EALs (to account for effects of elastic-eletron scattering) for applications in surface analysis by Auger-electron spectroscopy (AES) and X-ray photoelectron spectroscopy (XPS).

  14. Post-Retrieval Extinction Attenuates Cocaine Memories

    OpenAIRE

    Sartor, Gregory C.; Aston-Jones, Gary

    2013-01-01

    Recent studies have shown that post-retrieval extinction training attenuates fear and reward-related memories in both humans and rodents. This noninvasive, behavioral approach has the potential to be used in clinical settings to treat maladaptive memories that underlie several psychiatric disorders, including drug addiction. However, few studies to date have used a post-retrieval extinction approach to attenuate addiction-related memories. In the current study, we attempted to disrupt cocaine...

  15. Attenuation of Shock Waves using Perforated Plates

    Science.gov (United States)

    Pavan Kumar, CH V. L. C. S.; Hitesh Reddy, C.; Rahul Sai, L.; Dharani Kumar, K. S. S.; Nagaraja, S. R.

    2017-08-01

    The shock/blast waves generated due to explosions cause wide spread damage to the objects in its path. Different techniques have been used to attenuate shock wave over pressure, to reduce the catastrophic effects. Perforated plates can be used effectively to attenuate the shock wave pressure. In this paper shock wave interaction with perforated plates is simulated using COMSOL multiphysics software. The pressure drop varied from 43.75% to 26% for porosity varying from 10% to 40.

  16. Attenuation coefficients for water quality trading

    OpenAIRE

    Keller, AA; Chen, X.; Fox, J; Fulda, M; Dorsey, R.; Seapy, B; Glenday, J; E Bray

    2014-01-01

    Water quality trading has been proposed as a cost-effective approach for reducing nutrient loads through credit generation from agricultural or point source reductions sold to buyers facing costly options. We present a systematic approach to determine attenuation coefficients and their uncertainty. Using a process-based model, we determine attenuation with safety margins at many watersheds for total nitrogen (TN) and total phosphorus (TP) loads as they transport from point of load reduction t...

  17. Attenuation limits in longitudinal phononic crystals

    Science.gov (United States)

    Luschi, L.; Iannaccone, G.; Pieri, F.

    2017-12-01

    The acoustic attenuation inside the bandgaps is, together with the bandgap width, a fundamental design parameter for phononic-crystal-based systems. We discuss approximate expressions for the maximum attenuation inside the bandgaps of one-dimensional longitudinal phononic crystals and its dependence on the acoustic contrast and the fractional bandwidth. We provide different approximations at small and large fractional bandwidths, computed from the trace of the transmission matrix of the crystal elementary cell. We show that, for relatively small gaps, the attenuation is roughly proportional to the fractional bandwidth, in analogy with the flexural case. For larger gaps, a large attenuation can be obtained only for high (and possibly impractical) acoustic contrasts. Approximate expressions are validated through comparison with FEM results. We also derive asymptotic upper limits for the bandgap borders and show that high contrasts do not necessarily lead to wide bandgaps, a fact connected to geometrical phase inversion for the acoustic wave in the crystal. We finally compare the attenuation of flexural and longitudinal waves at a fixed fractional bandwidth and derive regions of optimum attenuation for the two propagation modes.

  18. Mechanisms of geometrical seismic attenuation

    Directory of Open Access Journals (Sweden)

    Igor B. Morozov

    2011-07-01

    Full Text Available In several recent reports, we have explained the frequency dependence of the apparent seismic quality-factor (Q observed in many studies according to the effects of geometrical attenuation, which was defined as the zero-frequency limit of the temporal attenuation coefficient. In particular, geometrical attenuation was found to be positive for most waves traveling within the lithosphere. Here, we present three theoretical models that illustrate the origin of this geometrical attenuation, and we investigate the causes of its preferential positive values. In addition, we discuss the physical basis and limitations of both the conventional and new attenuation models. For waves in media with slowly varying properties, geometrical attenuation is caused by variations in the wavefront curvature, which can be both positive (for defocusing and negative (for focusing. In media with velocity/density contrasts, incoherent reflectivity leads to geometrical-attenuation coefficients which are proportional to the mean squared reflectivity and are always positive. For «coherent» reflectivity, the geometrical attenuation is approximately zero, and the attenuation process can be described according to the concept of «scattering Q». However, the true meaning of this parameter is in describing the mean reflectivity within the medium, and not that of the traditional resonator quality factor known in mechanics. The general conclusion from these models is that non-zero and often positive levels of geometrical attenuation are common in realistic, heterogeneous media, both observationally and theoretically. When transformed into the conventional Q-factor form, this positive geometrical attenuation leads to Q values that quickly increase with frequency. These predictions show that the positive frequency-dependent Q observed in many datasets might represent artifacts of the transformations of the attenuation coefficients into Q.

  1. Live attenuated vaccines for invasive Salmonella infections

    Science.gov (United States)

    Tennant, Sharon M.; Levine, Myron M.

    2015-01-01

    Salmonella enterica serovar Typhi produces significant morbidity and mortality worldwide despite the fact that there are licensed S. Typhi vaccines available. This is primarily due to the fact that these vaccines are not used in the countries that most need them. There is growing recognition that an effective invasive Salmonella vaccine formulation must also prevent infection due to other Salmonella serovars. We anticipate that a multivalent vaccine that targets the following serovars will be needed to control invasive Salmonella infections worldwide: S. Typhi, S. Paratyphi A, S. Paratyphi B (currently uncommon but may become dominant again), S. Typhimurium, S. Enteritidis and S. Choleraesuis (as well as other Group C Salmonella). Live attenuated vaccines are an attractive vaccine formulation for use in developing as well as developed countries. Here, we describe the methods of attenuation that have been used to date to create live attenuated Salmonella vaccines and provide an update on the progress that has been made on these vaccines. PMID:25902362

  2. Two-dimensional dynamic fluid bowtie attenuators

    OpenAIRE

    Hermus, James R.; Szczykutowicz, Timothy P.

    2016-01-01

    Fluence field modulated (FFM) CT allows for improvements in image quality and dose reduction. To date, only one-dimensional modulators have been proposed, as the extension to two-dimensional (2-D) modulation is difficult with solid-metal attenuation-based fluence field modulated designs. This work proposes to use liquid and gas to attenuate the x-ray beam, as unlike solids, these materials can be arranged allowing for 2-D fluence modulation. The thickness of liquid and the pressure for a give...

  3. Fosfito de potássio na indução de resistência a Verticillium dahliae Kleb., em mudas de cacaueiro (Theobroma cacao L. Effect of potassium phosphite on the induction of resistance in cocoa seedlings (Theobroma cacao L. against Verticillium dahliae Kleb

    Directory of Open Access Journals (Sweden)

    Pedro Martins Ribeiro Júnior

    2006-08-01

    Full Text Available Há vários relatos da utilização de fosfitos no controle de doenças de plantas, por meio de ação direta, antifúngica e indireta por indução de resistência. Essa atuação como indutor é questionada, não sendo encontradas, em muitos desses trabalhos, evidências de respostas de defesa ativadas pelos sais de fosfito. Com o presente trabalho, objetivou-se estudar o efeito de doses (0,62; 1,25; 2,5 e 5 mL.L-1 de água de fosfito de potássio na indução de resistência em mudas de cacaueiro a V. dahliae, além de investigar os possíveis mecanismos envolvidos na resposta de defesa. Foram realizados experimentos no Laboratório de Fisiologia do Parasitismo e casa-de-vegetação do Departamento de Fitopatologia UFLA. A aplicação foliar do fosfito foi realizada 7 dias antes das inoculações e as avaliações de severidade foram realizadas aos 20, 30, 40, 50 e 60 dias após a inoculação. Foi realizado também um experimento para verificar o efeito tóxico direto e outro para avaliar a atividade das enzimas peroxidases e polifenoloxidases e a concentração de lignina. O tratamento com o fosfito de potássio (1,25 mL.L-1 de água proporcionou 10% de redução na área abaixo da curva de progresso da severidade da murcha-de-Verticillium (AACPD, 60 dias após aplicação foliar, não diferindo de nenhuma das doses, nem da testemunha. Todas as doses utilizadas apresentaram efeito fungitóxico, inibindo a germinação de V. dahliae. A aplicação do fosfito de potássio (1,25 mL.L-1 de água não induziu aumento na atividade das enzimas peroxidases e polifenoloxidases em relação à testemunha. Plantas tratadas com esse produto apresentaram um pequeno incremento na concentração de lignina, não apresentando diferença significativa da testemunha absoluta.There are several reports concerning with the use of phosphites for controlling of plant diseases, through direct action, antifungal, and indirect, by resistance induction. The

  4. Ativação de defesa em cacaueiro contra a murcha-de-verticílio por extratos naturais e acibenzolar-S-metil Activation of defence responses on cocoa against Verticillium wilt by natural extracts and acibenzolar-S-methyl

    Directory of Open Access Journals (Sweden)

    Ricardo Borges Pereira

    2008-02-01

    Full Text Available O objetivo deste trabalho foi avaliar o potencial de extratos fúngicos e vegetais na redução da murcha-de-verticílio do cacaueiro, as atividades da peroxidase e polifenoloxidase e o conteúdo de lignina. Mudas de cacaueiro foram pulverizadas com filtrado de micélio de Rhizopus sp. (FMR, quitosana de Rhizopus sp. (QMR e Trichoderma sp. (QMT, extratos de casca in natura e seca de maracujá, extrato metanólico de casca seca de frutos de maracujá (MMS e acibenzolar-S-metil (ASM - 0.2 mg mL-1 e sete dias depois, submetidas à inoculação de Verticillium dahliae. O ASM reduziu a murcha-de-verticílio em 38,0%, seguido dos extratos FMR, QMT, MMS e QMR, que apresentaram reduções em 22,8, 20,1, 19,2 e 15,7%, respectivamente, em relação à testemunha. Plantas pulverizadas com ASM ou FMR seguidas de inoculação apresentaram aumento da atividade de peroxidase aos oito dias após a pulverização, comparadas às respectivas testemunhas, com pico aos 18 dias após a pulverização. ASM e FMR aumentaram a atividade de polifenoloxidase aos quatro dias após a pulverização. Maiores concentrações de lignina foram obtidas em plantas tratadas com FMR e FMR seguido de inoculação. FMR é um potencial indutor de resistência para manejo de murcha-de-verticílio em cacaueiro.The objective of this work was to assess the potential of fungal and plant extracts on the reduction of Verticillium wilt of cocoa, the activities of the enzymes peroxidase and polyphenoloxidase, as well as the lignin content. Seedlings of cocoa were sprayed with the mycelial filtrate of Rhizopus sp. (FMR, chitosan from Rhizopus sp. (QMR and Trichoderma sp. (QMT, extracts of fresh and dry passion fruit peel, methanolic extract from dry passion fruit peel (MMS and acibenzolar-S-methyl (ASM - 0.2 mg mL-1 and, inoculed with Verticillium dahliae, seven days later. ASM reduced the cocoa Verticillium wilt in 38.0%. The extract FMR, QMT, MMS and QMR presented as well reductions of 22

  5. Touch Attenuates Infants' Physiological Reactivity to Stress

    Science.gov (United States)

    Feldman, Ruth; Singer, Magi; Zagoory, Orna

    2010-01-01

    Animal studies demonstrate that maternal touch and contact regulate infant stress, and handling during periods of maternal deprivation attenuates the stress response. To measure the effects of touch on infant stress reactivity during simulated maternal deprivation, 53 dyads were tested in two paradigms: still-face (SF) and still-face with maternal…

  6. Coffee Consumption Attenuates Insulin Resistance and Glucose ...

    African Journals Online (AJOL)

    olayemitoyin

    J. Physiol. Sci. 28(December 2013) 179–185 www.njps.com.ng. Coffee Consumption Attenuates Insulin Resistance and Glucose. Intolerance in Rats fed on High-Sucrose Diet. Morakinyo AO*, Adekunbi DA, Dada KA and Adegoke OA. Department of Physiology, College of Medicine of the University of Lagos, Lagos. Nigeria.

  7. Electrically tunable hot-silicon terahertz attenuator

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Minjie [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Vajtai, Robert; Ajayan, Pulickel M. [Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Kono, Junichiro, E-mail: kono@rice.edu [Department of Electrical and Computer Engineering, Rice University, Houston, Texas 77005 (United States); Department of Materials Science and NanoEngineering, Rice University, Houston, Texas 77005 (United States); Department of Physics and Astronomy, Rice University, Houston, Texas 77005 (United States)

    2014-10-06

    We have developed a continuously tunable, broadband terahertz attenuator with a transmission tuning range greater than 10{sup 3}. Attenuation tuning is achieved electrically, by simply changing the DC voltage applied to a heating wire attached to a bulk silicon wafer, which controls its temperature between room temperature and ∼550 K, with the corresponding free-carrier density adjusted between ∼10{sup 11 }cm{sup −3} and ∼10{sup 17 }cm{sup −3}. This “hot-silicon”-based terahertz attenuator works most effectively at 450–550 K (corresponding to a DC voltage variation of only ∼7 V) and completely shields terahertz radiation above 550 K in a frequency range of 0.1–2.5 THz. Both intrinsic and doped silicon wafers were tested and demonstrated to work well as a continuously tunable attenuator. All behaviors can be understood quantitatively via the free-carrier Drude model taking into account thermally activated intrinsic carriers.

  8. Coffee Consumption Attenuates Insulin Resistance and Glucose ...

    African Journals Online (AJOL)

    Coffee Consumption Attenuates Insulin Resistance and Glucose Intolerance in Rats fed on High-Sucrose Diet. ... Summary: Several epidemiological evidences indicate that consumption of coffee is associated with a lower risk of type 2 diabetes mellitus (T2DM) however; there is dearth of experimental data to support these ...

  9. Ultrasonic attenuation in rare-earth monoarsenides

    Indian Academy of Sciences (India)

    The toughness/fracture (G/BT) ratio is greater than 0.60, which implies that XAs compounds are brittle at room temperature. Further, the Debye temperature is computed using Debye average velocity as the input parameter. It helps in the characterization of lattice vibrations of a solid. In this work, ultrasonic attenuation due to ...

  10. GPR measurements of attenuation in concrete

    Science.gov (United States)

    Eisenmann, David; Margetan, Frank J.; Pavel, Brittney

    2015-03-01

    Ground-penetrating radar (GPR) signals from concrete structures are affected by several phenomenon, including: (1) transmission and reflection coefficients at interfaces; (2) the radiation patterns of the antenna(s) being used; and (3) the material properties of concrete and any embedded objects. In this paper we investigate different schemes for determining the electromagnetic (EM) attenuation of concrete from measured signals obtained using commercially-available GPR equipment. We adapt procedures commonly used in ultrasonic inspections where one compares the relative strengths of two or more signals having different travel paths through the material of interest. After correcting for beam spread (i.e., diffraction), interface phenomena, and equipment amplification settings, any remaining signal differences are assumed to be due to attenuation thus allowing the attenuation coefficient (say, in dB of loss per inch of travel) to be estimated. We begin with a brief overview of our approach, and then discuss how diffraction corrections were determined for our two 1.6 GHz GPR antennas. We then present results of attenuation measurements for two types of concrete using both pulse/echo and pitch/catch measurement setups.

  11. Anethum Graveolens Linn (Umbelliferae) Extract Attenuates Stress ...

    African Journals Online (AJOL)

    Anethum Graveolens Linn (Umbelliferae) Extract Attenuates Stress-induced Urinary Biochemical Changes and Improves Cognition in Scopolamineinduced Amnesic Rats. ... Conclusion: The aqueous extract of A. graveolens exhibited significant anti-stress, antioxidant and memory enhancing activities. The study provides a ...

  12. GPR measurements of attenuation in concrete

    Energy Technology Data Exchange (ETDEWEB)

    Eisenmann, David, E-mail: djeisen@cnde.iastate.edu; Margetan, Frank J., E-mail: djeisen@cnde.iastate.edu; Pavel, Brittney, E-mail: djeisen@cnde.iastate.edu [Center for Nondestructive Evaluation, Iowa State University, 1915 Scholl Road, Ames, IA 50011-3042 (United States)

    2015-03-31

    Ground-penetrating radar (GPR) signals from concrete structures are affected by several phenomenon, including: (1) transmission and reflection coefficients at interfaces; (2) the radiation patterns of the antenna(s) being used; and (3) the material properties of concrete and any embedded objects. In this paper we investigate different schemes for determining the electromagnetic (EM) attenuation of concrete from measured signals obtained using commercially-available GPR equipment. We adapt procedures commonly used in ultrasonic inspections where one compares the relative strengths of two or more signals having different travel paths through the material of interest. After correcting for beam spread (i.e., diffraction), interface phenomena, and equipment amplification settings, any remaining signal differences are assumed to be due to attenuation thus allowing the attenuation coefficient (say, in dB of loss per inch of travel) to be estimated. We begin with a brief overview of our approach, and then discuss how diffraction corrections were determined for our two 1.6 GHz GPR antennas. We then present results of attenuation measurements for two types of concrete using both pulse/echo and pitch/catch measurement setups.

  13. Microwave attenuation with composite of copper microwires

    Energy Technology Data Exchange (ETDEWEB)

    Gorriti, A.G.; Marin, P. [Instituto de Magnetismo Aplicado, (UCM-ADIF-CSIC) and Departamento de Fisica de Materiales (UCM). P.O. Box 155, Las Rozas, Madrid 28230 (Spain); Cortina, D. [Micromag S.L., Las Rozas, Madrid 28230 (Spain); Hernando, A., E-mail: antonio.hernando@adif.e [Instituto de Magnetismo Aplicado, (UCM-ADIF-CSIC) and Departamento de Fisica de Materiales (UCM). P.O. Box 155, Las Rozas, Madrid 28230 (Spain); Micromag S.L., Las Rozas, Madrid 28230 (Spain)

    2010-05-15

    It is shown that copper microwires composite media attenuates microwave reflection of metallic surfaces. We show how the distance to the metallic surface, as well as the length and volume fraction of microwires, determine the frequency of maximum absorption and the return loss level. Furthermore, we were able to fit the experimental results with a theoretical model based on Maxwell-Garnett mixing formula.

  14. Attenuation correction for small animal PET tomographs

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Patrick L [David Geffen School of Medicine at UCLA, Crump Institute for Molecular Imaging, University of California, 700 Westwood Plaza, Los Angeles, CA 90095 (United States); Rannou, Fernando R [Departamento de Ingenieria Informatica, Universidad de Santiago de Chile (USACH), Av. Ecuador 3659, Santiago (Chile); Chatziioannou, Arion F [David Geffen School of Medicine at UCLA, Crump Institute for Molecular Imaging, University of California, 700 Westwood Plaza, Los Angeles, CA 90095 (United States)

    2005-04-21

    Attenuation correction is one of the important corrections required for quantitative positron emission tomography (PET). This work will compare the quantitative accuracy of attenuation correction using a simple global scale factor with traditional transmission-based methods acquired either with a small animal PET or a small animal x-ray computed tomography (CT) scanner. Two phantoms (one mouse-sized and one rat-sized) and two animal subjects (one mouse and one rat) were scanned in CTI Concorde Microsystem's microPET (registered) Focus{sup TM} for emission and transmission data and in ImTek's MicroCAT{sup TM} II for transmission data. PET emission image values were calibrated against a scintillation well counter. Results indicate that the scale factor method of attenuation correction places the average measured activity concentration about the expected value, without correcting for the cupping artefact from attenuation. Noise analysis in the phantom studies with the PET-based method shows that noise in the transmission data increases the noise in the corrected emission data. The CT-based method was accurate and delivered low-noise images suitable for both PET data correction and PET tracer localization.

  15. Vertical diffuse attenuation coefficient (Kd) based optical ...

    Indian Academy of Sciences (India)

    The optical classification of the different water types provides vital input for studies related to primary productivity, water clarity and determination of euphotic depth. Image data of the IRS- P3 MOS-B, for Path 90 of 27th February, 1998 was used for deriving vertical diffuse attenuation Coeffcient () and an optical ...

  16. Switching Control for Adaptive Disturbance Attenuation

    NARCIS (Netherlands)

    Battistelli, Giorgio; Mari, Daniele; Selvi, Daniela; Tesi, Alberto; Tesi, Pietro

    The problem of adaptive disturbance attenuation is addressed in this paper using a switching control approach. A finite family of stabilizing controllers is pre-designed, with the assumption that, for any possible operating condition, at least one controller is able to achieve a prescribed level of

  17. Vertical diffuse attenuation coefficient (Kd) based optical ...

    Indian Academy of Sciences (India)

    R. Narasimhan (Krishtel eMaging) 1461 1996 Oct 15 13:05:22

    The optical classification of the different water types provides vital input for studies related to primary productivity, water clarity and determination of euphotic depth. Image data of the IRS-. P3 MOS-B, for Path 90 of 27th February, 1998 was used for deriving vertical diffuse attenuation coefficient (Kd) and an optical ...

  18. Evaluation of satellite derived spectral diffuse attenuation coefficients

    Digital Repository Service at National Institute of Oceanography (India)

    Suresh, T.; Talaulikar, M.; Desa, E.; Mascarenhas, A.A.M.Q.; Matondkar, S.G.P.

    Spectral diffuse attenuation K sub(d)(lambda) is an important apparent optical property that provide information about the attenuation of the spectral downwelling solar irradiance with depth in water. The spectral K sub(d)(lambda) at lambda = 412...

  19. Attenuation of seismic waves in Central Egypt

    Directory of Open Access Journals (Sweden)

    Mamdouh Abbas Morsy

    2013-06-01

    Full Text Available Attenuation of seismic waves in central Egypt had never been studied before. The results of the research on the seismic attenuation are based upon the information collected by the seismological network from 1998 to 2011. 855 earthquakes were selected from the Egyptian seismological catalog, with their epicenter distances between 15 and 150 km, their magnitudes ranging from 2 and 4.1 and focal depths reaching up to 30 km. The first systematic study of attenuation derived from the P-, S- and coda wave in the frequency range 1–24 Hz is presented. In the interpretation of the results both single and multiple scattering in a half space are considered. The single scattering model proposed by Sato (1977 was used. Two methods, the coda (Qc and the Multiple Lapse Time Window (MLTW method are used. The aim of this study is to validate these interpretations in the region and to try to identify the effects of attenuation due to intrinsic (Qi and scattering attenuation (Qsc. The mean Qc value calculated was Qc = (39 ± 1f1.0±0.009. The average Qc at 1.5 Hz is (53 ± 6 and Qc = (900 ± 195 at 24 Hz with Qo ranging between 23 and 107, where η ranging between 0.9 and 1.3. The quality factor (Q was estimated from spectra of P- and S-waves by applying a spectral ratio technique. The results show variations in Qp and QS as a function of frequency, according to the power law Q = 56η1.1. The seismic albedo is 0.7 at all stations and it mean that the earthquake activity is due to tectonic origin. The attenuation and frequency dependency for different paths and the correlation of the results with the geotectonic of the region are presented. The Qc values were calculated and correlated with the geology and tectonics of the area. The relatively low Qo and the high frequency dependency agree with the values of a region characterized by a low tectonic activity and vise versa.

  20. On the excess attenuation of sound in the atmosphere

    Science.gov (United States)

    Deloach, R.

    1975-01-01

    The attenuation suffered by an acoustic plane wave propagating from an elevated source to the ground, in excess of absorption losses, was studied. Reported discrepancies between attenuation measurements made in the field and theories which only account for absorption losses are discussed. It was concluded that the scattering of sound by turbulence results in a nonnegligible contribution to the total attenuation.

  1. Measurement of atomic number and mass attenuation coefficient in ...

    Indian Academy of Sciences (India)

    The linear attenuation coefficient (), mass attenuation coefficient (/ρ), total atomic cross-section (tot), total electronic cross-section (ele) and the effective atomic number (eff) were calculated for pure magnesium ferrite (MgFe2O4). The values of -ray mass attenuation coefficient were obtained using a NaI energy ...

  2. Comparison of Attenuation of petroleum hydrocarbons in surface ...

    African Journals Online (AJOL)

    Comparison of Attenuation of petroleum hydrocarbons in surface and subsurface soils amended with biostimulants. ... Results suggest that natural attenuation can be a viable remediation strategy in soils with neutral to alkaline pH and that low pH of amendment material used could reduce TPH attenuation. Keywords: ...

  3. Backus and Wyllie Averages for Seismic Attenuation

    Science.gov (United States)

    Qadrouh, Ayman N.; Carcione, José M.; Ba, Jing; Gei, Davide; Salim, Ahmed M.

    2017-09-01

    Backus and Wyllie equations are used to obtain average seismic velocities at zero and infinite frequencies, respectively. Here, these equations are generalized to obtain averages of the seismic quality factor (inversely proportional to attenuation). The results indicate that the Wyllie velocity is higher than the corresponding Backus quantity, as expected, since the ray velocity is a high-frequency limit. On the other hand, the Wyllie quality factor is higher than the Backus one, following the velocity trend, i.e., the higher the velocity (the stiffer the medium), the higher the attenuation. Since the quality factor can be related to properties such as porosity, permeability, and fluid viscosity, these averages can be useful for evaluating reservoir properties.

  4. Analysis of Signal Attenuation in UHF Band

    Directory of Open Access Journals (Sweden)

    Libor Michalek

    2015-01-01

    Full Text Available This paper deals with signal attenuation in ultra-high-frequency bands caused by rain. We focus mainly on the effect of the rain on the radio waves propagation in the frequency band 2.1 GHz. Two exact approaches for investigating this dependency are used. In the first approach, we use the fitting probability density function for determination Rician distribution K-factor. In the second approach, we want to find more concrete rain-rate dependency with using linear regression. The results achieved in our long-term investigation clearly indicate that the strong impact of rain itself is a minor. So-called secondary rain impacts such as scattering of reflections from wet surfaces cause the main attenuation contribution.

  5. Tricolor attenuation model for shadow detection.

    Science.gov (United States)

    Tian, Jiandong; Sun, Jing; Tang, Yandong

    2009-10-01

    Shadows, the common phenomena in most outdoor scenes, bring many problems in image processing and computer vision. In this paper, we present a novel method focusing on extracting shadows from a single outdoor image. The proposed tricolor attenuation model (TAM) that describe the attenuation relationship between shadow and its nonshadow background is derived based on image formation theory. The parameters of the TAM are fixed by using the spectral power distribution (SPD) of daylight and skylight, which are estimated according to Planck's blackbody irradiance law. Based on the TAM, a multistep shadow detection algorithm is proposed to extract shadows. Compared with previous methods, the algorithm can be applied to process single images gotten in real complex scenes without prior knowledge. The experimental results validate the performance of the model.

  6. The Attenuation of Swell Waves by Rain

    Science.gov (United States)

    Cavaleri, Luigi; Bertotti, Luciana

    2017-10-01

    Within the progressive improvement in wave modeling we focus on the attenuation of swell waves by rain. Till now ignored, the process is shown to be relevant, especially for the correct estimate of swell. Following the practical impossibility of devoted field experiments, we exploit the global model results over a period of more than four years to extract the tiny signal associated to the attenuation by rain. A direct comparison of the ratio model by altimeter significant wave heights versus the encountered rain amount hints to a marked related dependence. A proper quantification of the related physical effect requires a multiple step procedure that we describe in detail. We check the reliability of the results, and we provide the related source function ready for implementation in operational wave models.

  7. Implicit temporal expectation attenuates auditory attentional blink.

    Directory of Open Access Journals (Sweden)

    Dawei Shen

    Full Text Available Attentional blink (AB describes a phenomenon whereby correct identification of a first target impairs the processing of a second target (i.e., probe nearby in time. Evidence suggests that explicit attention orienting in the time domain can attenuate the AB. Here, we used scalp-recorded, event-related potentials to examine whether auditory AB is also sensitive to implicit temporal attention orienting. Expectations were set up implicitly by varying the probability (i.e., 80% or 20% that the probe would occur at the +2 or +8 position following target presentation. Participants showed a significant AB, which was reduced with the increased probe probability at the +2 position. The probe probability effect was paralleled by an increase in P3b amplitude elicited by the probe. The results suggest that implicit temporal attention orienting can facilitate short-term consolidation of the probe and attenuate auditory AB.

  8. Mars Pathfinder Airbag Impact Attenuation System

    Science.gov (United States)

    Waye, Donald; Cole, J. Kenneth; Rivellini, Tommaso P.

    1995-01-01

    The Mars Pathfinder spacecraft, scheduled for launch in December 1996, is designed to validate a low cost Entry, Descent, and Landing system and to perform scientific surface operations. The Jet Propulsion Laboratory and Sandia National Laboratories teamed to design, fabricate, test and validate a prototype 0.38 scale model of an airbag impact attenuation system. A computer code was developed to predict the performance of the airbag system. A test program in Sandia's High Altitude Chamber was performed to validate the code and demonstrate the feasibility of the airbag concept and design. In addition, freefall tests were performed at representative velocities to demonstrate the structural integrity of the airbag system design. The feasibility program demonstrated that the airbag impact attenuation design will protect the lander upon impact with the Martian surface.

  9. LCLS XTOD Attenuator System System Concept Report

    Energy Technology Data Exchange (ETDEWEB)

    Kishiyama, K; Roeben, M; Trent, J; Ryutov, D; Shen, S

    2006-04-12

    The attenuator system for the Linac Coherent Light Source (LCLS) X-ray Transport, Optics and Diagnostics (XTOD) system has been configured and analyzed by the Lawrence Livermore National Laboratory's New Technologies Engineering Division (NTED) as requested by the SLAC/LCLS program. The system layout, performance analyses and selection of the vacuum components are presented in this System Conceptual Review (SCR) report. Also included are the plans for prototype, procurement, mechanical integration, and the cost estimates.

  10. Two-dimensional dynamic fluid bowtie attenuators.

    Science.gov (United States)

    Hermus, James R; Szczykutowicz, Timothy P

    2016-01-01

    Fluence field modulated (FFM) CT allows for improvements in image quality and dose reduction. To date, only one-dimensional modulators have been proposed, as the extension to two-dimensional (2-D) modulation is difficult with solid-metal attenuation-based fluence field modulated designs. This work proposes to use liquid and gas to attenuate the x-ray beam, as unlike solids, these materials can be arranged allowing for 2-D fluence modulation. The thickness of liquid and the pressure for a given path length of gas were determined that provided the same attenuation as 30 cm of soft tissue at 80, 100, 120, and 140 kV. Liquid iodine, zinc chloride, cerium chloride, erbium oxide, iron oxide, and gadolinium chloride were studied. Gaseous xenon, uranium hexafluoride, tungsten hexafluoride, and nickel tetracarbonyl were also studied. Additionally, we performed a proof-of-concept experiment using a 96 cell array in which the liquid thickness in each cell was adjusted manually. Liquid thickness varied as a function of kV and chemical composition, with erbium oxide allowing for the smallest thickness. For the gases, tungsten hexaflouride required the smallest pressure to compensate for 30 cm of soft tissue. The 96 cell iodine attenuator allowed for a reduction in both dynamic range to the detector and scatter-to-primary ratio. For both liquids and gases, when k-edges were located within the diagnostic energy range used for imaging, the mean beam energy exhibited the smallest change with compensation amount. The thickness of liquids and the gas pressure seem logistically implementable within the space constraints of C-arm-based cone beam CT (CBCT) and diagnostic CT systems. The gas pressures also seem logistically implementable within the space and tube loading constraints of CBCT and diagnostic CT systems.

  11. Study of Sound Attenuation in Sediments.

    Science.gov (United States)

    1984-12-01

    experimental difficulties. In the ocean, the sediment is inaccesible , the propagation path is inhomoveneonis, and information on lavering usually has to... STANDARDS 1963 A RFPRODUCED AT GOVERNMENT EXPENSE Ln ~STUDY OF SOUND ATTENUATION IN SEDIMENTS Stephen R. Addison and Henry F. Bass PARGUM Report 84-03*A 4*I...measured porosity decreased to 0.39. The standard deviation in all these porosity measurements was 0.01. A porosity of 0.40 is used in all subsequent

  12. What Is an Attenuated Psychotic Symptom?

    DEFF Research Database (Denmark)

    Fusar-Poli, Paolo; Raballo, Andrea; Parnas, Josef

    2016-01-01

    Attenuated psychotic symptoms (APS) are the key criteria to identify the individuals at enhanced risk of developing psychotic disorders. Competing clinicians-rated or self-rated psychometric instruments can also be used to detect APS, which makes it difficult to interpret their actual clinical...... significance. This article summarizes the empirical differences between the clinicians-rated and self-rated interviews and explores the impact of the context (referral pathways, settings, and assessment procedures) on the clinical significance of the APS....

  13. Attenuation compensation for optical coherence tomography imaging

    Science.gov (United States)

    Chang, Shoude; Flueraru, Costel; Mao, Youxin; Sherif, Sherif

    2009-12-01

    Optical coherence tomography (OCT) is a noninvasive technique that provides micrometer-scale imaging of tissue. As most biological tissues are considered turbid, it causes attenuation of the OCT signal and limits the depth penetration. Although a few algorithms had been developed to compensate the attenuation, almost all of them need to extract the scattering parameters before doing the compensation procedure. Because the real biological samples are anisotropic and multilayer-like structure, it is not time-efficient to model and solve these scattering parameters. This paper introduces a new method to compensate the OCT signal attenuation in depth. By analyzing the input signal, a compensation function is adaptively derived for each A-scan line, which can be used effectively to compensate the energy loss in the large sections and enhance the details in the deep, dark-like areas. Three bio-samples, a piece of onion, a Poecilia Wingei fish and a piece of rabbit abdominal aorta, were used to test our method. OCT images obtained by a swept-source OCT system were processed by the proposed method. Results show the visualization of structures in OCT images has been evidently improved, especially in deep region.

  14. Broadband Vibration Attenuation Using Hybrid Periodic Rods

    Directory of Open Access Journals (Sweden)

    S. Asiri

    2008-12-01

    Full Text Available This paper presents both theoretically and experimentally a new kind of a broadband vibration isolator. It is a table-like system formed by four parallel hybrid periodic rods connected between two plates. The rods consist of an assembly of periodic cells, each cell being composed of a short rod and piezoelectric inserts. By actively controlling the piezoelectric elements, it is shown that the periodic rods can efficiently attenuate the propagation of vibration from the upper plate to the lower one within critical frequency bands and consequently minimize the effects of transmission of undesirable vibration and sound radiation. In such a system, longitudinal waves can propagate from the vibration source in the upper plate to the lower one along the rods only within specific frequency bands called the "Pass Bands" and wave propagation is efficiently attenuated within other frequency bands called the "Stop Bands". The spectral width of these bands can be tuned according to the nature of the external excitation. The theory governing the operation of this class of vibration isolator is presented and their tunable filtering characteristics are demonstrated experimentally as functions of their design parameters. This concept can be employed in many applications to control the wave propagation and the force transmission of longitudinal vibrations both in the spectral and spatial domains in an attempt to stop/attenuate the propagation of undesirable disturbances.

  15. Novel Intriguing Strategies Attenuating to Sarcopenia

    Directory of Open Access Journals (Sweden)

    Kunihiro Sakuma

    2012-01-01

    Full Text Available Sarcopenia, the age-related loss of skeletal muscle mass, is characterized by a deterioration of muscle quantity and quality leading to a gradual slowing of movement, a decline in strength and power, increased risk of fall-related injury, and, often, frailty. Since sarcopenia is largely attributed to various molecular mediators affecting fiber size, mitochondrial homeostasis, and apoptosis, the mechanisms responsible for these deleterious changes present numerous therapeutic targets for drug discovery. Resistance training combined with amino acid-containing supplements is often utilized to prevent age-related muscle wasting and weakness. In this review, we summarize more recent therapeutic strategies (myostatin or proteasome inhibition, supplementation with eicosapentaenoic acid (EPA or ursolic acid, etc. for counteracting sarcopenia. Myostatin inhibitor is the most advanced research with a Phase I/II trial in muscular dystrophy but does not try the possibility for attenuating sarcopenia. EPA and ursolic acid seem to be effective as therapeutic agents, because they attenuate the degenerative symptoms of muscular dystrophy and cachexic muscle. The activation of peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α in skeletal muscle by exercise and/or unknown supplementation would be an intriguing approach to attenuating sarcopenia. In contrast, muscle loss with age may not be influenced positively by treatment with a proteasome inhibitor or antioxidant.

  16. Seismic Attenuation Inversion with t* Using tstarTomog.

    Energy Technology Data Exchange (ETDEWEB)

    Preston, Leiph

    2014-09-01

    Seismic attenuation is defined as the loss of the seismic wave amplitude as the wave propagates excluding losses strictly due to geometric spreading. Information gleaned from seismic waves can be utilized to solve for the attenuation properties of the earth. One method of solving for earth attenuation properties is called t*. This report will start by introducing the basic theory behind t* and delve into inverse theory as it pertains to how the algorithm called tstarTomog inverts for attenuation properties using t* observations. This report also describes how to use the tstarTomog package to go from observed data to a 3-D model of attenuation structure in the earth.

  17. Intensity attenuation in the Pannonian Basin

    Science.gov (United States)

    Győri, Erzsébet; Gráczer, Zoltán; Szanyi, Gyöngyvér

    2015-04-01

    Ground motion prediction equations play a key role in seismic hazard assessment. Earthquake hazard has to be expressed in macroseismic intensities in case of seismic risk estimations where a direct relation to the damage associated with ground shaking is needed. It can be also necessary for shake map generation where the map is used for prompt notification to the public, disaster management officers and insurance companies. Although only few instrumental strong motion data are recorded in the Pannonian Basin, there are numerous historical reports of past earthquakes since the 1763 Komárom earthquake. Knowing the intensity attenuation and comparing them with relations of other areas - where instrumental strong motion data also exist - can help us to choose from the existing instrumental ground motion prediction equations. The aim of this work is to determine an intensity attenuation formula for the inner part of the Pannonian Basin, which can be further used to find an adaptable ground motion prediction equation for the area. The crust below the Pannonian Basin is thin and warm and it is overlain by thick sediments. Thus the attenuation of seismic waves here is different from the attenuation in the Alp-Carpathian mountain belt. Therefore we have collected intensity data only from the inner part of the Pannonian Basin and defined the boundaries of the studied area by the crust thickness of 30 km (Windhoffer et al., 2005). 90 earthquakes from 1763 until 2014 have sufficient number of macroseismic data. Magnitude of the events varies from 3.0 to 6.6. We have used individual intensity points to eliminate the subjectivity of drawing isoseismals, the number of available intensity data is more than 3000. Careful quality control has been made on the dataset. The different types of magnitudes of the used earthquake catalogue have been converted to local and momentum magnitudes using relations determined for the Pannonian Basin. We applied the attenuation formula by Sorensen

  18. Determination of the attenuation map in emission tomography

    CERN Document Server

    Zaidi, H

    2002-01-01

    Reliable attenuation correction methods for quantitative emission computed tomography (ECT) require accurate delineation of the body contour and often necessitate knowledge of internal anatomical structure. Two broad classes of methods have been used to calculate the attenuation map referred to as "transmissionless" and transmission-based attenuation correction techniques. While calculated attenuation correction belonging to the first class of methods is appropriate for brain studies, more adequate methods must be performed in clinical applications where the attenuation coefficient distribution is not known a priori, and for areas of inhomogeneous attenuation such as the chest. Measured attenuation correction overcomes this problem and utilizes different approaches to determine this map including transmission scanning, segmented magnetic resonance images or appropriately scaled X-ray CT scans acquired either independently on separate or simultaneously on multimodality imaging systems. Combination of data acqu...

  19. Estimation of stimulus attenuation in cochlear implants

    CSIR Research Space (South Africa)

    Smit, Jacoba E

    2009-03-01

    Full Text Available B/mm) in scalar fluids, while the Organ of Corti current length constants are 1.00 – 1.15 mm (7.55 – 8.69 dB/mm). Kral et al. (1998) and Hartmann and Klinke (1990) have reported attenuation slopes of around 3 dB/mm (length constant of about 3 mm) for monopolar... in cochlear stimulation. Ann N Y Acad Sci, 1983; 405: 137-45. 30 Blight AR. Computer simulation of action potentials and afterpotentials in mammalian myelinated axons: The case for a lower resistance myelin sheath. Neuroscience, 1985; 15: 13- 31...

  20. Vinpocetine attenuates lipid accumulation and atherosclerosis formation

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Yujun [Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642 (United States); Li, Jian-Dong [Center for Inflammation, Immunity and Infection, and Department of Biology, Georgia State University, Atlanta, GA 30303 (United States); Yan, Chen, E-mail: Chen_Yan@urmc.rochester.edu [Aab Cardiovascular Research Institute, Department of Medicine, University of Rochester, 601 Elmwood Ave, Rochester, NY 14642 (United States)

    2013-05-10

    Highlights: •Vinpocetine attenuates hyperlipidemia-induced atherosclerosis in a mouse model. •Vinpocetine antagonizes ox-LDL uptake and accumulation in macrophages. •Vinpocetine blocks the induction of ox-LDL receptor LOX-1 in vitro and in vivo. -- Abstract: Atherosclerosis, the major cause of myocardial infarction and stroke, is a chronic arterial disease characterized by lipid deposition and inflammation in the vessel wall. Cholesterol, in low-density lipoprotein (LDL), plays a critical role in the pathogenesis of atherosclerosis. Vinpocetine, a derivative of the alkaloid vincamine, has long been used as a cerebral blood flow enhancer for treating cognitive impairment. Recent study indicated that vinpocetine is a potent anti-inflammatory agent. However, its role in the pathogenesis of atherosclerosis remains unexplored. In the present study, we show that vinpocetine significantly reduced atherosclerotic lesion formation in ApoE knockout mice fed with a high-fat diet. In cultured murine macrophage RAW264.7 cells, vinpocetine markedly attenuated oxidized LDL (ox-LDL) uptake and foam cell formation. Moreover, vinpocetine greatly blocked the induction of ox-LDL receptor 1 (LOX-1) in cultured macrophages as well as in the LOX-1 level in atherosclerotic lesions. Taken together, our data reveal a novel role of vinpocetine in reduction of pathogenesis of atherosclerosis, at least partially through suppressing LOX-1 signaling pathway. Given the excellent safety profile of vinpocetine, this study suggests vinpocetine may be a therapeutic candidate for treating atherosclerosis.

  1. Method of attenuation of electromagnetic radiation

    Energy Technology Data Exchange (ETDEWEB)

    Reh, G.P.; Mawdsley, G.E.; Yaffe, M.J.

    1990-05-30

    A method for the protection of matter, including humans, by attenuation of electromagnetic radiation comprises providing the matter with a protective layer of an inorganic composition formed from at least two elements, or compounds thereof, selected from different specified groups. The elements provide complementary attenuation of the radiation, and may be selected to optimize protection against specific energy spectra. The inorganic composition may be in a carrier e.g. a polymer. The method may be used in a variety of ways e.g. in protection of humans from x-rays, gamma rays or other radiation, or in packaging applications, protection of equipment sensitive to radiation or the like. The inorganic composition comprises elements or compounds of Ac, Bi, Au, Pb, Hg, Pu, Po, Pa, Tl, Th and/or U together with elements or compounds of Sb, Ba, Cd, Ce, Cs, La, Pb, In, I, Ag, Te, Sn, W, Au, Ir, Hg, Os, Pt, Re, Ta and/or Tl. (author).

  2. Exercise Training During Bed Rest Attenuates Deconditioning

    Science.gov (United States)

    Greenleaf, J. E.; Hargens, Alan R. (Technical Monitor)

    1995-01-01

    A 30-day 6 deg. head-down bed rest study was conducted to evaluate high-intensity, short-duration, alternating isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent isokinetic exercise (IKE) training regiments designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (acclimation) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volume, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (a) attenuated the decrease in peak VO2 by 50%, (b) attenuated loss of red cell volume by 40%, but had no effect on loss of plasma volume, (c) induced positive body water balance, (d) had no adverse effect on quality of sleep or concentration, and (e) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regiments, and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

  3. Frequency ranges and attenuation of macroseismic effects

    Science.gov (United States)

    Tosi, Patrizia; De Rubeis, Valerio; Sbarra, Paola

    2017-09-01

    Macroseismic intensity is assessed on the basis of the effects caused by an earthquake. These effects reflect the expression of both the intensity and frequency of the ground motion, thus complicating prediction equation modelling. Here we analysed data of several macroseismic transitory effects caused by recent Italian earthquakes in order to study their attenuation as a function of magnitude and hypocentral distance and to obtain a specific prediction equation, of simple functional form, that could be applied to each of the effects under analysis. We found that the different attenuation behaviours could be clearly defined by the values of the specially formulated magnitude-distance scaling ratio (S), thus allowing to group the effects on the basis of the S value. The oscillation of hanging objects and liquids, together with the feeling of dizziness, were separated from most other variables, such as the effects of the earthquake on small objects, china and windows, which were caused by a vibration of higher frequency. Besides, the greater value of S, associated with the perception of the seismic sound, explained the peculiarity of this phenomenon. As a result, we recognized the frequency range associated with each effect through comparisons with the ground motion prediction equations and, in particular, with the 5 per cent damped horizontal response spectra. Here we show the importance of appropriately selecting the diagnostic elements to be used for intensity assessment in order to improve the correlation with ground motion.

  4. Glasses, Stress, Attenuation and Thermal Conductivity

    Science.gov (United States)

    Wu, Jiansheng; Yu, Clare

    2011-03-01

    A wide variety of amorphous materials exhibit similar behavior in their thermal properties. Examples include universal features in the specific heat,thermal conductivity, and ultrasonic attenuation. Recent experiments from the Parpia group at Cornell find that high stress silicon nitride thin film resonators exhibit a remarkably high Q factor, exceeding that of amorphous Si O2 by 2 to 3 orders of magnitude over a broad range of temperatures, and even exceeding that of single crystal silicon at room temperature. We present a model of why the stress reduces the attenuation. The basic assumption is that high stress increases the potential barriers of the excitations of defects that produce the loss, thus reducing the effective density of lossy fluctuators. We predict that high stress could lead to high thermal conductivity and low dielectric loss, making high stress SiN an excellent candidate as a substrate for integrated circuits. This work was supported by the Office of the Director of National Intelligence (ODNI), Intelligence Advanced Research Projects Activity (IARPA), through the Army Research Office.

  5. Omentin functions to attenuate cardiac hypertrophic response.

    Science.gov (United States)

    Matsuo, Kazuhiro; Shibata, Rei; Ohashi, Koji; Kambara, Takahiro; Uemura, Yusuke; Hiramatsu-Ito, Mizuho; Enomoto, Takashi; Yuasa, Daisuke; Joki, Yusuke; Ito, Masanori; Hayakawa, Satoko; Ogawa, Hayato; Kihara, Shinji; Murohara, Toyoaki; Ouchi, Noriyuki

    2015-02-01

    Cardiac hypertrophy occurs in many obesity-related conditions. Omentin is an adipose-derived plasma protein that is downregulated under obese conditions. Here, we investigated whether omentin modulates cardiac hypertrophic responses in vivo and in vitro. Systemic administration of an adenoviral vector expressing human omentin (Ad-OMT) to wild-type (WT) mice led to the attenuation of cardiac hypertrophy, fibrosis and ERK phosphorylation induced by transverse aortic constriction (TAC) or angiotensin II infusion. In cultured cardiomyocytes, stimulation with phenylephrine (PE) led to an increase in myocyte size, which was prevented by pretreatment with human omentin protein. Pretreatment of cardiomyocytes with omentin protein also reduced ERK phosphorylation in response to PE stimulation. Ad-OMT enhanced phosphorylation of AMP-activated protein kinase (AMPK) in the heart of WT mice after TAC operation. Blockade of AMPK activation by transduction with dominant-negative mutant forms of AMPK reversed the inhibitory effect of omentin on myocyte hypertrophy and ERK phosphorylation following PE stimulation. Moreover, fat-specific transgenic mice expressing human omentin showed reduced cardiac hypertrophy and ERK phosphorylation following TAC surgery compared to littermate controls. These data suggest that omentin functions to attenuate the pathological process of myocardial hypertrophy via the activation of AMPK in the heart, suggesting that omentin may represent a target molecule for the treatment of cardiac hypertrophy. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Effects of training on hearing protector attenuation

    Directory of Open Access Journals (Sweden)

    William J Murphy

    2011-01-01

    Full Text Available The effect of training instruction, whether presented as the manufacturer′s printed instructions, a short video training session specific to the product, or as a one-on-one training session was evaluated using four hearing protection devices with eight groups of subjects. Naïve subjects were recruited and tested using three different forms of training: written, video, and individual training. The group averages for A-weighted attenuation were not statistically significant when compared between the video or the written instruction conditions, regardless of presentation order. The experimenter-trained A-weighted attenuations were significantly greater than the written and video instruction for most of the protectors and groups. For each earplug, the noise reduction statistic for A-weighting (NRS A and the associated confidence intervals were calculated for the 80 th and 20 th percentiles of protection. Across subject groups for each protector, the differences between NRS A ratings were found to be not statistically significant. Several comparisons evaluating the order of testing, the type of testing, and statistical tests of the performance across the groups are presented.

  7. Engineering a Light-Attenuating Artificial Iris.

    Science.gov (United States)

    Shareef, Farah J; Sun, Shan; Kotecha, Mrignayani; Kassem, Iris; Azar, Dimitri; Cho, Michael

    2016-04-01

    Discomfort from light exposure leads to photophobia, glare, and poor vision in patients with congenital or trauma-induced iris damage. Commercial artificial iris lenses are static in nature to provide aesthetics without restoring the natural iris's dynamic response to light. A new photo-responsive artificial iris was therefore developed using a photochromic material with self-adaptive light transmission properties and encased in a transparent biocompatible polymer matrix. The implantable artificial iris was designed and engineered using Photopia, a class of photo-responsive materials (termed naphthopyrans) embedded in polyethylene. Photopia was reshaped into annular disks that were spin-coated with polydimethylsiloxane (PDMS) to form our artificial iris lens of controlled thickness. Activated by UV and blue light in approximately 5 seconds with complete reversal in less than 1 minute, the artificial iris demonstrates graded attenuation of up to 40% of visible and 60% of UV light. There optical characteristics are suitable to reversibly regulate the incident light intensity. In vitro cell culture experiments showed up to 60% cell death within 10 days of exposure to Photopia, but no significant cell death observed when cultured with the artificial iris with protective encapsulation. Nuclear magnetic resonance spectroscopy confirmed these results as there was no apparent leakage of potentially toxic photochromic material from the ophthalmic device. Our artificial iris lens mimics the functionality of the natural iris by attenuating light intensity entering the eye with its rapid reversible change in opacity and thus potentially providing an improved treatment option for patients with iris damage.

  8. Studies on attenuation of rotavirus. A comparison in piglets between virulent virus and its attenuated derivative.

    Science.gov (United States)

    Tzipori, S; Unicomb, L; Bishop, R; Montenaro, J; Vaelioja, L M

    1989-01-01

    The development of rotavirus vaccines against acute gastroenteritis for human infants has been accorded a very high priority. Several vaccine candidates all of which are live cultivated strains of animal origin have been tested in humans. However the nature of attenuation of these viruses for humans is unknown. In this study we have attenuated a pig rotavirus by 15 sequential passages in cell culture after which the virus no longer causes diarrhoea in piglets. The pathogenesis of infection of the attenuated rotavirus strain (AT/76 P15) in gnotobiotic piglets was compared with that of the virulent parent strain (AT/76). The pattern of virus replication in the small intestine was judged by histology, disaccharidase assay, immunoperoxidase labelling of gut sections using group A specific rotavirus antibody, and rotavirus antigen assay of gut contents. The parent strain caused variable but extensive infection that resulted in the complete destruction of mature small intestinal enterocytes and villous contraction within 3 days. Membrane bound digestive enzymes were lost, and profound watery diarrhoea and dehydration resulted in causing piglets to become moribund. In contrast attenuated virus appeared to propagate at a much slower pace. Fewer infected epithelial cells were detected at any one time. Destruction of enterocytes was never extensive enough to cause marked mucosal changes in histology. Membrane bound digestive enzymes remained near normal levels and there was little or no diarrhoea. Virus replication ceased after 6 days. It is concluded that attenuation of the porcine rotavirus strain studied was associated with its decreased ability to propagate in enterocytes after adaption to culture.

  9. An acoustic eikonal equation for attenuating VTI media

    KAUST Repository

    Hao, Qi

    2016-09-06

    We present an acoustic eikonal equation governing the complex-valued travel time of P-waves in attenuating, transversely isotropic media with a vertical symmetry axis (VTI). This equation is based on the assumption that the Pwave complex-valued travel time is independent of the Swave velocity parameter v in Thomsen\\'s notation and the attenuation coefficient A in the Thomsen-type notation for attenuating VTI media. We combine perturbation theory and Shanks transform to develop practical approximations to the attenuating acoustic eikonal equation, capable of admitting analytical description of the attenuation in homogeneous media. For a horizontal, attenuating VTI layer, we also derive non-hyperbolic approximations for the real and imaginary parts of the complex-valued reflection travel time.

  10. Surface Wave Attenuation in the Tibetan Plateau from Ambient Noise

    Science.gov (United States)

    2015-08-31

    AFRL-RV-PS- TR-2015-0150 AFRL-RV-PS- TR-2015-0150 SURFACE WAVE ATTENUATION IN THE TIBETAN PLATEAU FROM AMBIENT NOISE University of Illinois at...DATES COVERED (From - To) 01 May 2012 to 31 Aug 2015 4. TITLE AND SUBTITLE Surface Wave Attenuation in the Tibetan Plateau from Ambient Noise 5a...extract amplitude information from the empirical Green functions (EGF) derived from ambient noise correlations and to map the attenuation of the

  11. Usage of attenuation coefficients of some tissue-equivalent materials

    OpenAIRE

    TANIR, Ayşe Güneş; KETENCİ, Fatma Serap; BÖLÜKDEMİR, Mustafa Hicabi

    2015-01-01

    The total attenuation coefficients of 11 biological targets against photon energies were plotted within the energy range 1-10 MeV. From these plots a possible equation describing the relationship between photon energy and the total attenuation coefficient was derived. The suggested equation is mu/ rho = 0.0696/ surd E. To test the validity of the equation and to compare the results of the total attenuation coefficients of 3 tissue-equivalent materials (bolus, rice grains, and boiled rice) th...

  12. An Approximate Method for the Acoustic Attenuating VTI Eikonal Equation

    KAUST Repository

    Hao, Q.

    2017-05-26

    We present an approximate method to solve the acoustic eikonal equation for attenuating transversely isotropic media with a vertical symmetry axis (VTI). A perturbation method is used to derive the perturbation formula for complex-valued traveltimes. The application of Shanks transform further enhances the accuracy of approximation. We derive both analytical and numerical solutions to the acoustic eikonal equation. The analytic solution is valid for homogeneous VTI media with moderate anellipticity and strong attenuation and attenuation-anisotropy. The numerical solution is applicable for inhomogeneous attenuating VTI media.

  13. Imaging Rayleigh Wave Attenuation Beneath North America with USArray

    Science.gov (United States)

    Dalton, C. A.; Bao, X.; Jin, G.; Gaherty, J. B.

    2015-12-01

    The EarthScope USArray provides an opportunity to obtain detailed images of the continental upper mantle at an unprecedented scale. The majority of mantle models derived from USArray data to date contain spatial variations in seismic-wave speed; however, in many cases these data sets do not by themselves allow a non-unique interpretation. Joint interpretation of seismic attenuation and velocity models can improve upon the interpretations based only on velocity. Surface-wave amplitudes are sensitive to factors in addition to attenuation, including source excitation, focusing by elastic structure, and local site amplification. Because of the difficulty of isolating attenuation from these other factors, little is known about the attenuation structure of the North American upper mantle. In this study, Rayleigh wave travel time and amplitude in the period range 25-100 s are measured using an interstation cross-correlation technique. We consider three different approaches for separating the effects of local site amplification and attenuation on the amplitude measurements. The attenuation values determined with these three approaches contain the same first-order features, which gives us confidence that these features are robust: high attenuation in the western U.S. and low attenuation in the central and eastern U.S., with slightly higher attenuation along the eastern seaboard. However, we also identify several areas where we suspect the imaged attenuation values reflect unmodelled focusing effects rather than anelastic attenuation. We therefore identify attenuation values that are likely contaminated by unmodelled focusing effects using the Laplacian of the phase-velocity map, eliminate those values, and generate 2-D attenuation maps through a regional average of the remaining values. We also investigate the range of intrinsic shear-attenuation values that are suggested by the Rayleigh wave attenuation maps at periods between 40 and 80 s. This preliminary model is the

  14. Attenuation characteristic of UWB signals propagation in free space

    Science.gov (United States)

    Li, Meng; Huang, Zhonghua

    2016-10-01

    Researching attenuation characteristic of UWB signals propagation in free-space is necessary for ultra-wideband (UWB) radio fuze optimized design. Research attenuation characteristic of UWB signals propagation in free space can be achieved by learning attenuation characteristic of radio waves propagation in free-space and UWB signal power spectral density. 50ps, 100ps and 200ps of pulse width UWB fuze transmission narrow pulse signal propagation in free-space are simulated and analyzed. The attenuation of UWB signals at 3m, 6m and 9m are contrasted. The simulation, analysis and contrast is theoretical basis of UWB radio fuze optimized design.

  15. Enhanced Attenuation Technologies: Passive Soil Vapor Extraction

    Energy Technology Data Exchange (ETDEWEB)

    Vangelas, K.; Looney, B.; Kamath, R.; Adamson, D.; Newell, C.

    2010-03-15

    Passive soil vapor extraction (PSVE) is an enhanced attenuation (EA) approach that removes volatile contaminants from soil. The extraction is driven by natural pressure gradients between the subsurface and atmosphere (Barometric Pumping), or by renewable sources of energy such as wind or solar power (Assisted PSVE). The technology is applicable for remediating sites with low levels of contamination and for transitioning sites from active source technologies such as active soil vapor extraction (ASVE) to natural attenuation. PSVE systems are simple to design and operate and are more cost effective than active systems in many scenarios. Thus, PSVE is often appropriate as an interim-remedial or polishing strategy. Over the past decade, PSVE has been demonstrated in the U.S. and in Europe. These demonstrations provide practical information to assist in selecting, designing and implementing the technology. These demonstrations indicate that the technology can be effective in achieving remedial objectives in a timely fashion. The keys to success include: (1) Application at sites where the residual source quantities, and associated fluxes to groundwater, are relatively low; (2) Selection of the appropriate passive energy source - barometric pumping in cases with a deep vadose zone and barrier (e.g., clay) layers that separate the subsurface from the atmosphere and renewable energy assisted PSVE in other settings and where higher flow rates are required. (3) Provision of sufficient access to the contaminated vadose zones through the spacing and number of extraction wells. This PSVE technology report provides a summary of the relevant technical background, real-world case study performance, key design and cost considerations, and a scenario-based cost evaluation. The key design and cost considerations are organized into a flowchart that dovetails with the Enhanced Attenuation: Chlorinated Organics Guidance of the Interstate Technology and Regulatory Council (ITRC). The PSVE

  16. CT Attenuation Analysis of Carotid Intraplaque Hemorrhage.

    Science.gov (United States)

    Saba, L; Francone, M; Bassareo, P P; Lai, L; Sanfilippo, R; Montisci, R; Suri, J S; De Cecco, C N; Faa, G

    2017-11-30

    Intraplaque hemorrhage is considered a leading parameter of carotid plaque vulnerability. Our purpose was to assess the CT characteristics of intraplaque hemorrhage with histopathologic correlation to identify features that allow for confirming or ruling out the intraplaque hemorrhage. This retrospective study included 91 patients (67 men; median age, 65 ± 7 years; age range, 41-83 years) who underwent CT angiography and carotid endarterectomy from March 2010 to May 2013. Histopathologic analysis was performed for the tissue characterization and identification of intraplaque hemorrhage. Two observers assessed the plaque's attenuation values by using an ROI (≥ 1 and ≤2 mm2). Receiver operating characteristic curve, Mann-Whitney, and Wilcoxon analyses were performed. A total of 169 slices were assessed (59 intraplaque hemorrhage, 63 lipid-rich necrotic core, and 47 fibrous); the average values of the intraplaque hemorrhage, lipid-rich necrotic core, and fibrous tissue were 17.475 Hounsfield units (HU) and 18.407 HU, 39.476 HU and 48.048 HU, and 91.66 HU and 93.128 HU, respectively, before and after the administration of contrast medium. The Mann-Whitney test showed a statistically significant difference of HU values both in basal and after the administration of contrast material phase. Receiver operating characteristic analysis showed a statistical association between intraplaque hemorrhage and low HU values, and a threshold of 25 HU demonstrated the presence of intraplaque hemorrhage with a sensitivity and specificity of 93.22% and 92.73%, respectively. The Wilcoxon test showed that the attenuation of the plaque before and after administration of contrast material is different (intraplaque hemorrhage, lipid-rich necrotic core, and fibrous tissue had P values of .006, .0001, and .018, respectively). The results of this preliminary study suggest that CT can be used to identify the presence of intraplaque hemorrhage according to the attenuation. A threshold of 25

  17. Gas sensor with attenuated drift characteristic

    Science.gov (United States)

    Chen, Ing-Shin [Danbury, CT; Chen, Philip S. H. [Bethel, CT; Neuner, Jeffrey W [Bethel, CT; Welch, James [Fairfield, CT; Hendrix, Bryan [Danbury, CT; Dimeo, Jr., Frank [Danbury, CT

    2008-05-13

    A sensor with an attenuated drift characteristic, including a layer structure in which a sensing layer has a layer of diffusional barrier material on at least one of its faces. The sensor may for example be constituted as a hydrogen gas sensor including a palladium/yttrium layer structure formed on a micro-hotplate base, with a chromium barrier layer between the yttrium layer and the micro-hotplate, and with a tantalum barrier layer between the yttrium layer and an overlying palladium protective layer. The gas sensor is useful for detection of a target gas in environments susceptible to generation or incursion of such gas, and achieves substantial (e.g., >90%) reduction of signal drift from the gas sensor in extended operation, relative to a corresponding gas sensor lacking the diffusional barrier structure of the invention

  18. Controlled Attenuation Parameter And Alcoholic Hepatic Steatosis

    DEFF Research Database (Denmark)

    Thiele, Maja; Rausch, Vanessa; Fluhr, Gabriele

    2018-01-01

    ≥S2 = 0.78; 0.72-0.83) and severe steatosis with good accuracy (AUC S3 = 0.82; 0.75-0.88). CAP was superior to bright liver echo pattern by regular ultrasound. CAP above 290 dB/m ruled in any steatosis with 88% specificity and 92% positive predictive value, while CAP below 220 dB/m ruled out....... LAY SUMMARY: Controlled attenuation parameter (CAP) is a new ultrasound based technique for measuring fat content in the liver, but has never been tested for fatty liver due to alcohol. We here examine 562 patients in a multicenter setting. We show that CAP highly correlates with liver fat...... detoxification on CAP. METHODS: Cross-sectional, biopsy-controlled, diagnostic study in four European liver centers. Consecutive alcohol-overusing patients underwent concomitant CAP, regular ultrasound and liver biopsy. In addition, we measured CAP before and after admission for detoxification in a separate...

  19. Release and attenuation of fluorocarbons in landfills

    DEFF Research Database (Denmark)

    Kjeldsen, Peter; Scheutz, Charlotte

    2003-01-01

    Several halocarbons with very high global warming and ozone depleting potentials have been used as blowing agent for insulation foam in refrigerators and freezers. Many appliances are shredded after the end of their useful life. Release experiments carried out in the laboratory on insulation foam...... blown with CFC-11, HCFC-141b, HFC- 134a, and HFC-245fa revealed that most of the blowing agent is not released to the atmosphere during a six-week period following the shredding process. The fraction which is released in the six-week period is highly dependent on how fine the foam is shredded....... The residual blowing agent remaining after the six-week period may be very slowly released if the integrity of the foam particles with respect to diffusional properties is kept after disposal of the foam waste in landfills. Laboratory experiments simulating attenuation processes in the landfilled waste...

  20. Mode propagation and attenuation in lined ducts

    CERN Document Server

    BI, Wenping

    2014-01-01

    Optimal impedance for each mode is an important concept in an infinitely long duct lined with uniform absorption material. However it is not valid for finite length linings. This is because that the modes in lined ducts are not power-orthogonal; the total sound power is not equal to the sum of the sound power of each mode; cross-power terms may play important roles. In this paper, we study sound propagation and attenuation in an infinite rigid duct lined with a finite length of lining impedance. The lining impedance may be axial segments and circumferentially non-uniform. We propose two new physical quantities Kp and S to describe the self-overlap of the left eigenfunction and right eigenfunction of one mode and the normalized overlap between modes, respectively. The two new physical quantities describe totally the mode behaviors in lined ducts.

  1. Glutathione attenuates uranyl toxicity in Lactococcus lactis

    Energy Technology Data Exchange (ETDEWEB)

    Fahmy, Karim; Oertel, Jana [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biophysics; Obeid, M. [Technische Univ. Dresden (Germany); Solioz, M. [Bern Univ. (Switzerland)

    2017-06-01

    We investigated the role of intracellular glutathione (GSH), which in a large number of taxa plays a role in the protection against the toxicity of heavy metals. Anaerobically grown Lactococcus lactis containing an inducible GSH synthesis pathway was used as a model organism allowing the study of GSH-dependent uranyl detoxification without interference from additional reactive oxygen species. Microcalorimetric measurements of the metabolic heat showed that intracellular GSH attenuates the toxicity of uranium at a concentration in the range of 10-150 μM. Isothermal titration calorimetry revealed the endothermic binding of U(VI) to the carboxyl group(s) of GSH. The data indicate that the primary detoxifying mechanism is the intracellular sequestration of carboxyl-coordinated U(VI) into an insoluble complex with GSH.

  2. LIVE ATTENUATED VACCINES FOR THE IMMUNOPROPHYLAXIS

    Directory of Open Access Journals (Sweden)

    O. A. Shamsutdinova

    2017-01-01

    Full Text Available The review focuses on the history of the production of live antiviral vaccines and their use for the prevention of infectious diseases. It was noted that before the beginning of the 20th century, only three live vaccines were developed and put into practice — against smallpox, rabies, plague. The discovery of D. Enders, T.H. Weller and F.Ch. Robins of the ability of the polio virus, and then of a number of other viruses, to reproduce in vitro in cell cultures of various types, greatly expanded the studies on the production of attenuated strains of viruses for live vaccines. The historical stages of obtaining and introducing live vaccines for the prevention of smallpox, poliomyelitis, measles, rubella, and mumps are highlighted. Arguments in favor of the use of associated vaccine preparations for the prevention of viral infections are presented. Various variants of the strategy and tactics of using live vaccines, which are used for specific prevention of viral infections in different countries, are described. The review provides information on technological methods for obtaining antiviral vaccines. The publications testifying to the development of specific reactions in immunized vaccine strains of measles, mumps, poliomyelitis and rubella viruses, such as aseptic meningitis (vaccine strains of mumps virus, acute arthritis (vaccine rubella virus strains, temperature reactions, rash (vaccine strains of the virus Measles, vaccine-associated paralytic poliomyelitis (VAPP vaccine vaccine poliovirus. It is particularly noted that the long experience of vaccine prevention both in Russia and abroad convincingly shows that the risk of developing post-vaccination complications is incommensurably lower than the risk of causing harm to health from the corresponding infections. It is concluded that despite introduction of new third and fourth generation vaccines into practice, live attenuated vaccines do not lose their significance and are used in vaccine

  3. Targeting Phospholipase D4 Attenuates Kidney Fibrosis.

    Science.gov (United States)

    Trivedi, Priyanka; Kumar, Ramya K; Iyer, Ashwin; Boswell, Sarah; Gerarduzzi, Casimiro; Dadhania, Vivekkumar P; Herbert, Zach; Joshi, Nikita; Luyendyk, James P; Humphreys, Benjamin D; Vaidya, Vishal S

    2017-12-01

    Phospholipase D4 (PLD4), a single-pass transmembrane glycoprotein, is among the most highly upregulated genes in murine kidneys subjected to chronic progressive fibrosis, but the function of PLD4 in this process is unknown. Here, we found PLD4 to be overexpressed in the proximal and distal tubular epithelial cells of murine and human kidneys after fibrosis. Genetic silencing of PLD4, either globally or conditionally in proximal tubular epithelial cells, protected mice from the development of fibrosis. Mechanistically, global knockout of PLD4 modulated innate and adaptive immune responses and attenuated the upregulation of the TGF-β signaling pathway and α1-antitrypsin protein (a serine protease inhibitor) expression and downregulation of neutrophil elastase (NE) expression induced by obstructive injury. In vitro, treatment with NE attenuated TGF-β-induced accumulation of fibrotic markers. Furthermore, therapeutic targeting of PLD4 using specific siRNA protected mice from folic acid-induced kidney fibrosis and inhibited the increase in TGF-β signaling, decrease in NE expression, and upregulation of mitogen-activated protein kinase signaling. Immunoprecipitation/mass spectrometry and coimmunoprecipitation experiments confirmed that PLD4 binds three proteins that interact with neurotrophic receptor tyrosine kinase 1, a receptor also known as TrkA that upregulates mitogen-activated protein kinase. PLD4 inhibition also prevented the folic acid-induced upregulation of this receptor in mouse kidneys. These results suggest inhibition of PLD4 as a novel therapeutic strategy to activate protease-mediated degradation of extracellular matrix and reverse fibrosis. Copyright © 2017 by the American Society of Nephrology.

  4. Engineering a Light-Attenuating Artificial Iris

    Science.gov (United States)

    Shareef, Farah J.; Sun, Shan; Kotecha, Mrignayani; Kassem, Iris; Azar, Dimitri; Cho, Michael

    2016-01-01

    Purpose Discomfort from light exposure leads to photophobia, glare, and poor vision in patients with congenital or trauma-induced iris damage. Commercial artificial iris lenses are static in nature to provide aesthetics without restoring the natural iris's dynamic response to light. A new photo-responsive artificial iris was therefore developed using a photochromic material with self-adaptive light transmission properties and encased in a transparent biocompatible polymer matrix. Methods The implantable artificial iris was designed and engineered using Photopia, a class of photo-responsive materials (termed naphthopyrans) embedded in polyethylene. Photopia was reshaped into annular disks that were spin-coated with polydimethylsiloxane (PDMS) to form our artificial iris lens of controlled thickness. Results Activated by UV and blue light in approximately 5 seconds with complete reversal in less than 1 minute, the artificial iris demonstrates graded attenuation of up to 40% of visible and 60% of UV light. There optical characteristics are suitable to reversibly regulate the incident light intensity. In vitro cell culture experiments showed up to 60% cell death within 10 days of exposure to Photopia, but no significant cell death observed when cultured with the artificial iris with protective encapsulation. Nuclear magnetic resonance spectroscopy confirmed these results as there was no apparent leakage of potentially toxic photochromic material from the ophthalmic device. Conclusions Our artificial iris lens mimics the functionality of the natural iris by attenuating light intensity entering the eye with its rapid reversible change in opacity and thus potentially providing an improved treatment option for patients with iris damage. PMID:27116547

  5. A study of ultrasonic velocity and attenuation on polycrystalline Ni ...

    Indian Academy of Sciences (India)

    Unknown

    (longitudinal and transverse) and attenuation has been qualitatively explained with the help of the temperature variation of the magneto-crystalline anisotropy constant. Keywords. Ferrites; magnetic properties; ultrasonic velocity; attenuation; domain walls. 1. Introduction. There is an abundant literature on the propagation of.

  6. Simulation on the shock attenuation behavior of coupled RHA and ...

    African Journals Online (AJOL)

    Based from the results, coupled RHA and sandwich composite structure configuration exhibit highest attenuation capability of 61.3% respectively. The study can be used as reference tool for the application related to automotive, naval and aeronautical structures, oil and gas industry. Keywords: shock attenuation; composite; ...

  7. Periportal low-attenuation: a CT sign of lymphatic obstruction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Hoon; Kim, Chong Soo; Yang, Doo Hyun; Lee, Sang Yong; Lee, Young Whan; Chung, Gyung Ho; Han, Young Min; Sohn, Myung Hee; Choi, Ki Chul [Chonbuk National University College of Medicine, Jeonju (Korea, Republic of)

    1995-07-15

    Periportal low attenuation, defined as a low attenuation rim around the portal vein and its branches which is seen on contrast material-enhanced CT scans, has been described in a variety of conditions. We tried to document that lymphatic obstruction is one of the major cause of periportal low attenuation. We retrospectively analyzed 57 cases of periportal low attenuation of abdominal CT scans and also reviewed the surgical records in 32 cases. Lymph node enlargement in the hepatoduodenal ligament which is a main lymphatic channel from the liver were analyzed the calculated the ratio of the transeverse diameter between the inferior vena cava and the aorta at the level of right adrenal gland. After complete surgical interruption of the lymphatic drainage from the liver in a dog, follow up CT scans were obtained and correlated with pathologic findings. Fifty patients (88%) had underlying disease which could cause impairment of lymphatic drainage. Periportal low attenuation was identified in several clinical conditions, including surgical lymph node dissection, lymphadenopathy in the hepatoduodenal ligament, blunt trauma. In animal model, CT scan showed prominent periportal low attenuation at 5 days after surgery. Histologic examination revealed numerous dilated lymphatic vessels and a marked lymphedema in the connective tissues surrounding the portal vein and its major branches. One of the major cause of periportal low attenuation was impaired lymphatic drainage and periportal low attenuation corresponding to the numerous dilated lymphatic vessels and a marked lymphedema in the connective tissues surrounding the portal vein and its major branches.

  8. Determination of gamma ray attenuation coefficients of Al–4% Cu ...

    Indian Academy of Sciences (India)

    Gamma ray attenuation coefficients of metal matrix composites have been investigated. For this purpose, the linear attenuation coefficients of composites containing boron carbide (B4C) at different rates have been measured using a gamma spectrometer that contains a NaI(Tl) detector and MCA at 662, 1173 and 1332 keV, ...

  9. Determination of gamma ray attenuation coefficients of Al–4% Cu ...

    Indian Academy of Sciences (India)

    Administrator

    Abstract. Gamma ray attenuation coefficients of metal matrix composites have been investigated. For this purpose, the linear attenuation coefficients of composites containing boron carbide (B4C) at different rates have been measured using a gamma spectrometer that contains a NaI(Tl) detector and MCA at 662, 1173 and.

  10. Spatial and seasonal variation in wave attenuation over Zostera noltii

    Science.gov (United States)

    Paul, M.; Amos, C. L.

    2011-08-01

    Wave attenuation is a recognized function of sea grass ecosystems which is believed to depend on plant characteristics. This paper presents field data on wave attenuance collected over a 13 month period in a Zostera noltii meadow. The meadow showed a strong seasonality with high shoot densities in summer (approximately 4,600 shoots/m2) and low densities in winter (approximately 600 shoots/m2). Wave heights and flow velocities were measured along a transect at regular intervals during which the site was exposed to wind waves and boat wakes that differ in wave period and steepness. This difference was used to investigate whether wave attenuation by sea grass changes with hydrodynamic conditions. A seasonal change in wave attenuation was observed from the data. Results suggest that a minimum shoot density is necessary to initiate wave attenuation by sea grass. Additionally, a dependence of wave attenuation on hydrodynamics was found. Results suggest that the threshold shoot density varies with wave period and a change in energy dissipation toward the shore was observed once this threshold was exceeded. An attempt was made to quantify the bed roughness of the meadow; the applicability of this roughness value in swaying vegetation is discussed. Finally, the drag coefficient for the meadow was computed: A relationship between wave attenuance and vegetation Reynolds number was found which allows comparing the wave attenuating effect of Zostera noltii to other plant species.

  11. Light attenuation characteristics of glacially-fed lakes

    Science.gov (United States)

    Rose, Kevin C.; Hamilton, David P.; Williamson, Craig E.; McBride, Chris G.; Fischer, Janet M.; Olson, Mark H.; Saros, Jasmine E.; Allan, Mathew G.; Cabrol, Nathalie

    2014-07-01

    Transparency is a fundamental characteristic of aquatic ecosystems and is highly responsive to changes in climate and land use. The transparency of glacially-fed lakes may be a particularly sensitive sentinel characteristic of these changes. However, little is known about the relative contributions of glacial flour versus other factors affecting light attenuation in these lakes. We sampled 18 glacially-fed lakes in Chile, New Zealand, and the U.S. and Canadian Rocky Mountains to characterize how dissolved absorption, algal biomass (approximated by chlorophyll a), water, and glacial flour contributed to attenuation of ultraviolet radiation (UVR) and photosynthetically active radiation (PAR, 400-700 nm). Variation in attenuation across lakes was related to turbidity, which we used as a proxy for the concentration of glacial flour. Turbidity-specific diffuse attenuation coefficients increased with decreasing wavelength and distance from glaciers. Regional differences in turbidity-specific diffuse attenuation coefficients were observed in short UVR wavelengths (305 and 320 nm) but not at longer UVR wavelengths (380 nm) or PAR. Dissolved absorption coefficients, which are closely correlated with diffuse attenuation coefficients in most non-glacially-fed lakes, represented only about one quarter of diffuse attenuation coefficients in study lakes here, whereas glacial flour contributed about two thirds across UVR and PAR. Understanding the optical characteristics of substances that regulate light attenuation in glacially-fed lakes will help elucidate the signals that these systems provide of broader environmental changes and forecast the effects of climate change on these aquatic ecosystems.

  12. Wave attenuation in mangroves; a quantitative approach to field observations

    NARCIS (Netherlands)

    Horstman, Erik; Dohmen-Janssen, Catarine M.; Narra, P.M.F.; van den Berg, N.J.F.; Siemerink, M.; Hulscher, Suzanne J.M.H.

    2014-01-01

    Coastal mangroves, dwelling at the interface between land and sea, provide an important contribution to reducing risk from coastal hazards by attenuating incident waves and by trapping and stabilizing sediments. This paper focusses on relations between vegetation densities, wave attenuation rates,

  13. Ultrasonic velocity and attenuation anisotropy of shales, Whitby, United Kingdom

    NARCIS (Netherlands)

    Zhubayev, Alimzhan; Houben, M.E.|info:eu-repo/dai/nl/370588843; Smeulders, David; Barnhoorn, A.|info:eu-repo/dai/nl/304843636

    We have conducted ultrasonic experiments, between 0.3 and 1 MHz, to measure velocity and attenuation (Q−1) anisotropy of P- and S-waves in dry Whitby Mudstone samples as a function of stress. We found the degree of anisotropy to be as large as 70% for velocity and attenuation. The sensitivity of

  14. Ultrasonic velocity and attenuation anisotropy of shales, Whitby, United Kingdom

    NARCIS (Netherlands)

    Zhubayev, A.; Houben, M.E.; Smeulders, D.M.J.; Barnhoorn, A.

    2015-01-01

    We have conducted ultrasonic experiments, between 0.3 and 1 MHz, to measure velocity and attenuation (Q?1) anisotropy of P- and S-waves in dry Whitby Mudstone samples as a function of stress. We found the degree of anisotropy to be as large as 70% for velocity and attenuation. The sensitivity of

  15. Ultrasound attenuation dependence on air compression or expansion processes

    NARCIS (Netherlands)

    Jakevicius, L.; Demcenko, A.; Mardosaite, R.

    2010-01-01

    In this work variation of ultrasonic attenuation coefficient is analyzed in terms of air compression or expansion processes. In closed spaces changing air volume, the ultrasound attenuation coefficient depends on thermodynamic processes which occur during the air volume change. Two limiting cases

  16. Attenuation of Cardiovascular response by ß-blocker esmolol during ...

    African Journals Online (AJOL)

    Cardiovascular responses to laryngoscopy and intubation have long been recognized and various efforts have been made to attenuate this response. The aim of this study was to evaluate the efficacy and safety of ß-blocker esmolol in attenuating cardiovascular response to laryngoscopy and tracheal intubation in the ...

  17. Attenuated radon transform: theory and application in medicine and biology

    Energy Technology Data Exchange (ETDEWEB)

    Gullberg, G.T.

    1979-06-01

    A detailed analysis is given of the properties of the attenuated Radon transform and of how increases in photon attenuation influence the numerical accuracy and computation efficiency of iterative and convolution algorithms used to determine its inversion. The practical applications for this work involve quantitative assessment of the distribution of injected radiopharmaceuticals and radionuclides in man and animals for basic physiological and biochemical studies as well as clinical studies in nuclear medicine. A mathematical structure is developed using function theory and the theory of linear operators on Hilbert spaces which lends itself to better understanding the spectral properties of the attenuated Radon transform. The continuous attenuated Radon transform reduces to a matrix operator for discrete angular and lateral sampling, and the reconstruction problem reduces to a system of linear equations. For the situation of variable attenuation coefficient frequently found in nuclear medicine applications of imaging the heart and chest, the procedure developed in this thesis involves iterative techniques of performing the generalized inverse. For constant attenuation coefficient less than 0.15 cm/sup -1/, convolution methods can reliably reconstruct a 30 cm object with 0.5 cm resolution. However, for high attenuation coefficients or for the situation where there is variable attenuation such as reconstruction of distribution of isotopes in the heart, iterative techniques developed in this thesis give the best results. (ERB)

  18. Doxycycline Attenuated Pulmonary Fibrosis Induced by Bleomycin in Mice

    OpenAIRE

    Fujita, Masaki; Ye, Qing; Ouchi, Hiroshi; Harada, Eiji; Inoshima, Ichiro; Kuwano, Kazuyoshi; Nakanishi, Yoichi

    2006-01-01

    The administration of doxycycline prior to bleomycin in mice attenuated pulmonary fibrosis. Bronchoalveolar neutrophil influx and gelatinase activity, but not caseinolytic activity, were attenuated by doxycycline. Established fibrosis was not affected by doxycycline. Thus, doxycycline might be useful for slowing down pulmonary fibrosis by biological activity other than antibacterial activity.

  19. Slant-Path Rain Attenuation Statistics over Nigeria | Adefolalu ...

    African Journals Online (AJOL)

    The study shows that attenuation is higher for western, southern, or lower altitude stations. Also attenuation of horizontally polarized waves exceed that of vertical polarization by increasing margins at higher frequencies, which makes vertical polarization more preferable at higher microwave frequencies. Thus, the emerging ...

  20. Attenuation correction for the NIH ATLAS small animal PET scanner

    CERN Document Server

    Yao, Rutao; Liow, JeihSan; Seidel, Jurgen

    2003-01-01

    We evaluated two methods of attenuation correction for the NIH ATLAS small animal PET scanner: 1) a CT-based method that derives 511 keV attenuation coefficients (mu) by extrapolation from spatially registered CT images; and 2) an analytic method based on the body outline of emission images and an empirical mu. A specially fabricated attenuation calibration phantom with cylindrical inserts that mimic different body tissues was used to derive the relationship to convert CT values to (I for PET. The methods were applied to three test data sets: 1) a uniform cylinder phantom, 2) the attenuation calibration phantom, and 3) a mouse injected with left bracket **1**8F right bracket FDG. The CT-based attenuation correction factors were larger in non-uniform regions of the imaging subject, e.g. mouse head, than the analytic method. The two methods had similar correction factors for regions with uniform density and detectable emission source distributions.

  1. EFFECTS OF RAIN ATTENUATION ON SATELLITE COMMUNICATION LINK

    Directory of Open Access Journals (Sweden)

    G. N. Ezeh

    2014-06-01

    Full Text Available Rain attenuation is a major challenge to microwave satellite communication especially at frequencies above 10 GHz, causing unavailability of signals most of the time. Rain attenuation predictions have become one of the vital considerations while setting up a satellite communication link. In this study, rain attenuation models, cumulative distribution curves and other analytical tools for successful prediction of rain attenuation are presented. A three year Rain rate data was obtained from the Nigeria Meteorological Agency (NIMET database in addition to experimental data. Of the three prediction models used in the study, Ajayi model gave the range of values closest to the experimental data. A correctional factor was determined as 1.0988 and used to modify the Ajayi model. This modification to Ajayi’s model enabled its rain attenuation values conform more closely to the experimental result.

  2. Scratch Drive Actuator Driven Self-assembled Variable Optical Attenuator

    Science.gov (United States)

    Lee, Chengkuo; Lai, Yen-Jyh; Wu, Chia-Yu; Lin, Yu-Shen; Tasi, Ming Hung; Huang, Ruey-Shing; Lin, Min-Shyong

    2004-06-01

    This paper describes the new concept and design for a self-assembled variable optical attenuator (VOA) derived by using surface micromachining technology. A residual stress-induced flexure curved beam with corrugated trench anchors can lift up the reflective mirror shutter. This self-assembled reflective shutter can be driven by a set of scratch drive actuator (SDA), then slides into the spacing between input and output fiber ends. The attenuation range of proposed microelectromechanical systems (MEMS) VOA is determined by the vertical position of self-assembled pop-up polysilicon reflective shutter in which it is controlled by the value of applied dc voltage. This new VOA demonstrates continuous attenuation capability and wide attenuation range based on using an electrostatic actuator that is a new residual stress-induced flexure curved beam with corrugated-trench anchors. This device exhibits attenuation range of 70 dB and insertion loss less than 1 dB.

  3. Backscatter and attenuation characterization of ventricular myocardium

    Science.gov (United States)

    Gibson, Allyson Ann

    2009-12-01

    This Dissertation presents quantitative ultrasonic measurements of the myocardium in fetal hearts and adult human hearts with the goal of studying the physics of sound waves incident upon anisotropic and inhomogeneous materials. Ultrasound has been used as a clinical tool to assess heart structure and function for several decades. The clinical usefulness of this noninvasive approach has grown with our understanding of the physical mechanisms underlying the interaction of ultrasonic waves with the myocardium. In this Dissertation, integrated backscatter and attenuation analyses were performed on midgestational fetal hearts to assess potential differences in the left and right ventricular myocardium. The hearts were interrogated using a 50 MHz transducer that enabled finer spatial resolution than could be achieved at more typical clinical frequencies. Ultrasonic data analyses demonstrated different patterns and relative levels of backscatter and attenuation from the myocardium of the left ventricle and the right ventricle. Ultrasonic data of adult human hearts were acquired with a clinical imaging system and quantified by their magnitude and time delay of cyclic variation of myocardial backscatter. The results were analyzing using Bayes Classification and ROC analysis to quantify potential advantages of using a combination of two features of cyclic variation of myocardial backscatter over using only one or the other feature to distinguish between groups of subjects. When the subjects were classified based on hemoglobin A1c, the homeostasis model assessment of insulin resistance, and the ratio of triglyceride to high-density lipoprotein-cholesterol, differences in the magnitude and normalized time delay of cyclic variation of myocardial backscatter were observed. The cyclic variation results also suggested a trend toward a larger area under the ROC curve when information from magnitude and time delay of cyclic variation is combined using Bayes classification than when

  4. Sulforaphane attenuates EGFR signaling in NSCLC cells.

    Science.gov (United States)

    Chen, Chi-Yuan; Yu, Zhu-Yun; Chuang, Yen-Shu; Huang, Rui-Mei; Wang, Tzu-Chien V

    2015-06-03

    EGFR, a receptor tyrosine kinase (RTK), is frequently overexpressed and mutated in non-small cell lung cancer (NSCLC). Tyrosine kinase inhibitors (TKIs) have been widely used in the treatment of many cancers, including NSCLC. However, intrinsic and acquired resistance to TKI remains a common obstacle. One strategy that may help overcome EGFR-TKI resistance is to target EGFR for degradation. As EGFR is a client protein of heat-shock protein 90 (HSP90) and sulforaphane is known to functionally regulate HSP90, we hypothesized that sulforaphane could attenuate EGFR-related signaling and potentially be used to treat NSCLC. Our study revealed that sulforaphane displayed antitumor activity against NSCLC cells both in vitro and in vivo. The sensitivity of NSCLC cells to sulforaphane appeared to positively correlate with the inhibition of EGFR-related signaling, which was attributed to the increased proteasomal degradation of EGFR. Combined treatment of NSCLC cells with sulforaphane plus another HSP90 inhibitor (17-AAG) enhanced the inhibition of EGFR-related signaling both in vitro and in vivo. We have shown that sulforaphane is a novel inhibitory modulator of EGFR expression and is effective in inhibiting the tumor growth of EGFR-TKI-resistant NSCLC cells. Our findings suggest that sulforaphane should be further explored for its potential clinical applications against NSCLC.

  5. Impact energy attenuation performance of football headgear

    Science.gov (United States)

    McIntosh, A.; McCrory, P.

    2000-01-01

    Objectives—Commercially available football head protectors were tested to determine their impact energy attenuation performance and ability to reduce the likelihood of concussion. Methods—Prospective study using standardised impact test methods with both rigid (magnesium) and Hybrid III headforms. Results—Eight commercially available head protectors from six manufacturers were tested. The magnitude of the headform accelerations increased as the drop height was increased, ranging from a minimum of 64 g from a height of 0.2 m to a maximum of 1132 g from a height of 0.6 m. The head injury criterion and maximum headform acceleration values followed a similar trend. A steep increase was noted in the magnitude of maximum headform acceleration and head injury criterion when the drop height was increased from 0.4 to 0.5 m. This indicates that the foam material was completely compressed at an impact energy above about 20 J and therefore offers little protection against impacts of greater severity. Repeated tests using a drop height of 0.3 m showed that some helmets exhibit a "memory" effect, whereby impact performance is reduced by up to 50% with repeated impacts. Conclusions—Laboratory tests indicate that current commercially available football headgear performance will not reduce the likelihood of concussion. The absence of internationally recognised standards for soft headgear designed to ameliorate concussion is a major deficiency in sports injury prevention. Key Words: football; headgear; helmet; head; concussion PMID:11049142

  6. Mid-European seismic attenuation anomaly

    Science.gov (United States)

    Málek, Jiří; Brokešová, Johana; Vackář, Jiří

    2017-08-01

    Macroseismic studies of various historical earthquakes with epicenters in the Eastern Alps region have shown a significant elongation of isoseismals in the North-West direction. Such an anomalous attenuation of seismic waves in Central Europe is investigated on the basis of instrumental records of two moderate-size earthquakes in the Vienna Basin, which occurred in September and October 2013. It has been found that for both earthquakes the peak amplitudes of both velocity and acceleration are considerably higher to the North-West of the epicenters compared to the other directions. The peak ground velocity amplitudes at comparable epicentral distances but different azimuths may vary by as much as one order of magnitude. The inspection of individual seismograms suggests that the phenomenon is associated mainly with the propagation of S waves. Significant differences in frequency content of the seismic waves radiated to different azimuths are also demonstrated. The maximum predominant frequency was not observed at stations closest to the epicenters but about 250 km away, in the Bohemian Massif. The possible causes of these observations are briefly discussed on the basis of an elementary data analysis but further research and in-depth analysis is required to elucidate the causes of these phenomena.

  7. Silibinin attenuates allergic airway inflammation in mice

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yun Ho [Department of Anatomy, Medical School, Institute for Medical Sciences, Chonbuk National University, Jeonju, Jeonbuk 561-756 (Korea, Republic of); Jin, Guang Yu [Department of Radiology, Yanbian University Hospital, YanJi 133002 (China); Guo, Hui Shu [Centralab, The First Affiliated Hospital of Dalian Medical University, Dalian 116011 (China); Piao, Hong Mei [Department of Respiratory Medicine, Yanbian University Hospital, YanJi 133000 (China); Li, Liang chang; Li, Guang Zhao [Department of Anatomy and Histology and Embryology, Yanbian University School of Basic Medical Sciences, 977 Gongyuan Road, YanJi 133002, Jilin (China); Lin, Zhen Hua [Department of Pathology, Yanbian University School of Basic Medical Sciences, YanJi 133000 (China); Yan, Guang Hai, E-mail: ghyan@ybu.edu.cn [Department of Anatomy and Histology and Embryology, Yanbian University School of Basic Medical Sciences, 977 Gongyuan Road, YanJi 133002, Jilin (China)

    2012-10-26

    Highlights: Black-Right-Pointing-Pointer Silibinin diminishes ovalbumin-induced inflammatory reactions in the mouse lung. Black-Right-Pointing-Pointer Silibinin reduces the levels of various cytokines into the lung of allergic mice. Black-Right-Pointing-Pointer Silibinin prevents the development of airway hyperresponsiveness in allergic mice. Black-Right-Pointing-Pointer Silibinin suppresses NF-{kappa}B transcriptional activity. -- Abstract: Allergic asthma is a chronic inflammatory disease regulated by coordination of T-helper2 (Th2) type cytokines and inflammatory signal molecules. Silibinin is one of the main flavonoids produced by milk thistle, which is reported to inhibit the inflammatory response by suppressing the nuclear factor-kappa B (NF-{kappa}B) pathway. Because NF-{kappa}B activation plays a pivotal role in the pathogenesis of allergic inflammation, we have investigated the effect of silibinin on a mouse ovalbumin (OVA)-induced asthma model. Airway hyperresponsiveness, cytokines levels, and eosinophilic infiltration were analyzed in bronchoalveolar lavage fluid and lung tissue. Pretreatment of silibinin significantly inhibited airway inflammatory cell recruitment and peribronchiolar inflammation and reduced the production of various cytokines in bronchoalveolar fluid. In addition, silibinin prevented the development of airway hyperresponsiveness and attenuated the OVA challenge-induced NF-{kappa}B activation. These findings indicate that silibinin protects against OVA-induced airway inflammation, at least in part via downregulation of NF-{kappa}B activity. Our data support the utility of silibinin as a potential medicine for the treatment of asthma.

  8. Obesity attenuates gender differences in cardiovascular mortality.

    Science.gov (United States)

    Song, Xin; Tabák, Adam G; Zethelius, Björn; Yudkin, John S; Söderberg, Stefan; Laatikainen, Tiina; Stehouwer, Coen D A; Dankner, Rachel; Jousilahti, Pekka; Onat, Altan; Nilsson, Peter M; Satman, Ilhan; Vaccaro, Olga; Tuomilehto, Jaakko; Qiao, Qing

    2014-10-19

    To estimate cardiovascular disease (CVD) mortality in relation to obesity and gender. Data from 11 prospective cohorts from four European countries including 23 629 men and 21 965 women, aged 24 to 99 years, with a median follow-up of 7.9 years were analyzed. Hazards ratios (HR) for CVD mortality in relation to baseline body mass index (BMI), waist circumference (WC), waist-to-hip ratio (WHR) and waist-to-height ratio (WHtR) were estimated using Cox proportional hazards models with age as the timescale. Men had higher CVD mortality than women in all four BMI categories (obesity defined by WC, WHR or WHtR. The gender difference was slightly smaller in obese than in non-obese individuals; but the interaction was statistically significant only between gender and WC (p = 0.02), and WHtR (p = 0.01). None of the interaction terms was significant among non-diabetic individuals. Men had higher CVD mortality than women across categories of anthropometric measures of obesity. The gender difference was attenuated in obese individuals, which warrants further investigation.

  9. Statins attenuate polymethylmethacrylate-mediated monocyte activation.

    LENUS (Irish Health Repository)

    Laing, Alan J

    2012-02-03

    BACKGROUND: Periprosthetic osteolysis precipitates aseptic loosening of components, increases the risk of periprosthetic fracture and, through massive bone loss, complicates revision surgery and ultimately is the primary cause for failure of joint arthroplasty. The anti-inflammatory properties of HMG-CoA reductase inhibitors belonging to the statin family are well recognized. We investigated a possible role for status in initiating the first stage of the osteolytic cycle, namely monocytic activation. METHODS: We used an in vitro model of the human monocyte\\/macrophage inflammatory response to poly-methylmethacrylate (PMMA) particles after pretreat-ing cells with cerivastatin, a potent member of the statin family. Cell activation based upon production of TNF-alpha and MCP-1 cytokines was analyzed and the intracellular Raf-MEK-ERK signal transduction pathway was evaluated using western blot analysis, to identify its role in cell activation and in any cerivastatin effects observed. RESULTS: We found that pretreatment with cerivastatin significantly abrogates the production of inflammatory cytokines TNF-alpha and MCP-1 by human monocytes in response to polymethylmethacrylate particle activation. This inflammatory activation and attenuation appear to be mediated through the intracellular Raf-MEK-ERK pathway. INTERPRETATION: We propose that by intervening at the upstream activation stage, subsequent osteoclast activation and osteolysis can be suppressed. We believe that the anti-inflammatory properties of statins may potentially play a prophylactic role in the setting of aseptic loosening, and in so doing increase implant longevity.

  10. Minocycline Attenuates Iron-Induced Brain Injury.

    Science.gov (United States)

    Zhao, Fan; Xi, Guohua; Liu, Wenqaun; Keep, Richard F; Hua, Ya

    2016-01-01

    Iron plays an important role in brain injury after intracerebral hemorrhage (ICH). Our previous study found minocycline reduces iron overload after ICH. The present study examined the effects of minocycline on the subacute brain injury induced by iron. Rats had an intracaudate injection of 50 μl of saline, iron, or iron + minocycline. All the animals were euthanized at day 3. Rat brains were used for immunohistochemistry (n = 5-6 per each group) and Western blotting assay (n = 4). Brain swelling, blood-brain barrier (BBB) disruption, and iron-handling proteins were measured. We found that intracerebral injection of iron resulted in brain swelling, BBB disruption, and brain iron-handling protein upregulation (p minocycline with iron significantly reduced iron-induced brain swelling (n = 5, p Minocycline significantly decreased albumin protein levels in the ipsilateral basal ganglia (p minocycline co-injected animals. In conclusion, the present study suggests that minocycline attenuates brain swelling and BBB disruption via an iron-chelation mechanism.

  11. A contrast source method for nonlinear acoustic wave fields in media with spatially inhomogeneous attenuation

    NARCIS (Netherlands)

    Demi, L.; Van Dongen, K.W.A.; Verweij, M.D.

    2011-01-01

    Experimental data reveals that attenuation is an important phenomenon in medical ultrasound. Attenuation is particularly important for medical applications based on nonlinear acoustics, since higher harmonics experience higher attenuation than the fundamental. Here, a method is presented to

  12. Radio wave propagation through vegetation: Factors influencing signal attenuation

    Science.gov (United States)

    Savage, Nick; Ndzi, David; Seville, Andrew; Vilar, Enric; Austin, John

    2003-10-01

    The paper describes an extensive wideband channel sounding measurement campaign to investigate signal propagation through vegetation. The measurements have been conducted at three frequencies (1.3, 2 and 11.6 GHz) at sites with different measurement geometries and tree species. The data have been used to evaluate current narrowband empirical vegetation attenuation models and study the prevailing propagation mechanisms. Evaluation of the modified exponential decay (MED), maximum attenuation (MA) and nonzero gradient (NZG) models show that on a site by site basis, the NZG model gives the best prediction of excess attenuation due to vegetation. The MA model has been found to be the worst of the three models. The studies have shown that the measurement site used to obtain the NZG model parameter values given in () [2001] is influenced by metal lampposts and passing traffic, and thus was based on corrupted data. The results show that the leaf state, measurement geometry and vegetation density are more important factors influencing signal attenuation than tree species or leaf shape. Generally, the 11.6 GHz signal was attenuated much more than the 1.3 and 2 GHz signals by vegetation in-leaf, but the differences in attenuation were not significant in the out-of-leaf state. A successful excess attenuation model due to vegetation must consider the measurement geometry and vegetation descriptive parameters as well as any contributions from ground reflection and/or diffraction over the top or round edges of the trees.

  13. Believing and perceiving: authorship belief modulates sensory attenuation.

    Directory of Open Access Journals (Sweden)

    Andrea Desantis

    Full Text Available Sensory attenuation refers to the observation that self-generated stimuli are attenuated, both in terms of their phenomenology and their cortical response compared to the same stimuli when generated externally. Accordingly, it has been assumed that sensory attenuation might help individuals to determine whether a sensory event was caused by themselves or not. In the present study, we investigated whether this dependency is reciprocal, namely whether sensory attenuation is modulated by prior beliefs of authorship. Participants had to judge the loudness of auditory effects that they believed were either self-generated or triggered by another person. However, in reality, the sounds were always triggered by the participants' actions. Participants perceived the tones' loudness attenuated when they believed that the sounds were self-generated compared to when they believed that they were generated by another person. Sensory attenuation is considered to contribute to the emergence of people's belief of authorship. Our results suggest that sensory attenuation is also a consequence of prior belief about the causal link between an action and a sensory change in the environment.

  14. Broadband Lg Attenuation Modeling in the Middle East

    Energy Technology Data Exchange (ETDEWEB)

    Pasyanos, M E; Matzel, E M; Walter, W R; Rodgers, A J

    2008-08-21

    We present a broadband tomographic model of Lg attenuation in the Middle East derived from source- and site-corrected amplitudes. Absolute amplitude measurements are made on hand-selected and carefully windowed seismograms for tens of stations and thousands of crustal earthquakes resulting in excellent coverage of the region. A conjugate gradient method is used to tomographically invert the amplitude dataset of over 8000 paths over a 45{sup o} x 40{sup o} region of the Middle East. We solve for Q variation, as well as site and source terms, for a wide range of frequencies ranging from 0.5-10 Hz. We have modified the standard attenuation tomography technique to more explicitly define the earthquake source expression in terms of the seismic moment. This facilitates the use of the model to predict the expected amplitudes of new events, an important consideration for earthquake hazard or explosion monitoring applications. The attenuation results have a strong correlation to tectonics. Shields have low attenuation, while tectonic regions have high attenuation, with the highest attenuation at 1 Hz is found in eastern Turkey. The results also compare favorably to other studies in the region made using Lg propagation efficiency, Lg/Pg amplitude ratios and two-station methods. We tomographically invert the amplitude measurements for each frequency independently. In doing so, it appears the frequency-dependence of attenuation is not compatible with the power law representation of Q(f), an assumption that is often made.

  15. An acoustic eikonal equation for attenuating orthorhombic media

    KAUST Repository

    Hao, Qi

    2017-04-06

    Attenuating orthorhombic models are often used to describe the azimuthal variation of the seismic wave velocity and amplitude in finely layered hydrocarbon reservoirs with vertical fractures. In addition to the P-wave related medium parameters, shear wave parameters are also present in the complex eikonal equation needed to describe the P-wave complex-valued traveltime in an attenuating orthorhombic medium, which increases the complexity of using the P-wave traveltime to invert for the medium parameters in practice. Here, we use the acoustic assumption to derive an acoustic eikonal equation that approximately governs the complex-valued traveltime of P-waves in an attenuating orthorhombic medium. For a homogeneous attenuating orthorhombic media, we solve the eikonal equation using a combination of the perturbation method and Shanks transform. For a horizontal attenuating orthorhombic layer, both the real and imaginary part of the complex-valued reflection traveltime have nonhyperbolic behaviors in terms of the source-receiver offset. Similar to the roles of normal moveout (NMO) velocity and anellipticity, the attenuation NMO velocity and the attenuation anellipticity characterize the variation of the imaginary part of the complex-valued reflection traveltime around zero source-receiver offset.

  16. Comparison of Nitrate Attenuation Characterization Methods for Groundwater Remediation

    Science.gov (United States)

    Carroll, K. C.; Jordan, F. L.; Glenn, E. P.; Waugh, J.; Brusseau, M. L.

    2008-12-01

    Nitrate released from a former uranium mine tailings stockpile has contaminated groundwater near Monument Valley, Arizona. The results of previous studies suggest that nitrate attenuation is occurring at the site, but the feasibility of using natural attenuation as a remediation strategy remains uncertain. This investigation characterized the occurrence and rate of natural attenuation at the site using several methods. Spatial and temporal nitrate concentration data collected from a transect of monitoring wells located along the plume centerline were analyzed to evaluate overall rates of natural attenuation. The occurrence and rate of denitrification was evaluated through microcosm experiments, nitrogen isotopic fractionation analysis, and solute transport modeling. First-order rate coefficients calculated for each method were comparable. The composite natural attenuation rate coefficient was larger than the denitrification rate coefficient, which suggests that a combination of biological decay and dispersion/diffusion processes control nitrate attenuation at the site. Model simulations were conducted to estimate the time required for nitrate concentrations in the plume to decrease to 10 mg/L under existing conditions, which was approximately 150 years. Additional simulations were conducted to assess the potential reduction in cleanup time that would result from implementing enhanced denitrification via either methanol or ethanol injection. The results indicated that cleanup would be attained in approximately one-third the time estimated for natural attenuation.

  17. Wave attenuation over porous seabeds: A numerical study

    Science.gov (United States)

    Torres-Freyermuth, Alec; Brocchini, Maurizio; Corvaro, Sara; Pintado-Patiño, Jose Carlos

    2017-09-01

    We investigate wave attenuation over porous seabeds by means of a phase- and depth- resolving numerical model that solves the Volume-Averaged Reynolds-Averaged Navier-Stokes (VARANS) equations. The numerical model is calibrated with laboratory data from Corvaro et al. (2010). The numerical model predicts the wave attenuation and the velocity field near the porous bed for different regular wave conditions. Subsequently, a parametric analysis on the physical characteristics of the porous media is made to investigate their relative role on wave attenuation. The results of the analysis indicate nonlinear dependencies of wave attenuation on both, total porosity and mean grain diameter. The widely used parabolic model in terms of the dispersiveness parameter predicts both types of dependencies, effectively. Hence, new parametric formulations are derived for the determination of the coefficients involved in the parabolic model for each type of dependence. On the other hand, the role of the spectral shape on the wave spectrum bulk dissipation is investigated. Numerical results for irregular waves show a clear dependence of the dissipation rate with the Ursell (Ur) parameter. The dissipation rate becomes sensitive to frequency spreading for Ur attenuation with respect to an f - 4 formulation. Finally, bispectral analysis of irregular wave propagation allow us to investigate the mechanism of wave attenuation. The numerical results suggest that energy is directly dissipated at the peak frequency, whereas nonlinear energy transfer plays an important role in energy attenuation at higher harmonics.

  18. EMC characteristics of composite structure - Electric/electromagnetic shielding attenuation

    Science.gov (United States)

    Wegertseder, P.; Breitsameter, R.

    1989-09-01

    The paper reports electric/electromagnetic shielding-attenuation experiments performed on different test boxes built with the same materials and processes as those to be used for the construction of a helicopter. The measurements are performed in the frequency range of 14 to 18 GHz, and the effects of different composite materials, jointing and bonding of structure parts of the boxes, application and bonding of the mesh, the construction of access panels, and conductive seals on these panels are assessed. It is demonstrated that moderate electric/electromagnetic shielding-attenuation values can be achieved by composite structures made from carbon, and materials and procedures required for high shielding attenuation are discussed.

  19. Cine CT for Attenuation Correction in Cardiac PET/CT

    Science.gov (United States)

    Alessio, Adam M.; Kohlmyer, Steve; Branch, Kelley; Chen, Grace; Caldwell, James; Kinahan, Paul

    2008-01-01

    In dual-modality PET/CT systems, the CT scan provides the attenuation map for PET attenuation correction. The current clinical practice of obtaining a single helical CT scan provides only a snapshot of the respiratory cycle, whereas PET occurs over multiple respiratory cycles. Misalignment of the attenuation map and emission image because of respiratory motion causes errors in the attenuation correction factors and artifacts in the attenuation-corrected PET image. To rectify this problem, we evaluated the use of cine CT, which acquires multiple low-dose CT images during a respiratory cycle. We evaluated the average and the intensity-maximum image of cine CT for cardiac PET attenuation correction. Methods Cine CT data and cardiac PET data were acquired from a cardiac phantom and from multiple patient studies. The conventional helical CT, cine CT, and PET data of an axially translating phantom were evaluated with and without respiratory motion. For the patient studies, we acquired 2 cine CT studies for each PET acquisition in a rest–stress 13N-ammonia protocol. Three readers visually evaluated the alignment of 74 attenuation image sets versus the corresponding emission image and determined whether the alignment provided acceptable or unacceptable attenuation-corrected PET images. Results In the phantom study, the attenuation correction from helical CT caused a major artifactual defect in the lateral wall on the PET image. The attenuation correction from the average and from the intensity-maximum cine CT images reduced the defect by 20% and 60%, respectively. In the patient studies, 77% of the cases using the average of the cine CT images had acceptable alignment and 88% of the cases using the intensity maximum of the cine CT images had acceptable alignment. Conclusion Cine CT offers an alternative to helical CT for compensating for respiratory motion in the attenuation correction of cardiac PET studies. Phantom studies suggest that the average and the intensity

  20. One hertz seismic attenuation for low frequency gravitational waves interferometers

    Energy Technology Data Exchange (ETDEWEB)

    Mantovani, Maddalena [Universita di Siena Via Roma 56-53100 Siena (Italy)]. E-mail: mantovan@ego-gw.it; DeSalvo, Riccardo [California Institute of Technology 18-34, Pasadena, CA 91125 (United States)

    2005-12-01

    This article describes a mechanical vertical attenuation system capable to provide large attenuation factors above 1Hz. This system is derived from, and improves, the passive Geometric Anti-Spring seismic attenuation filters minimizing their vertical resonant frequency by means of a tunable electromagnetic spring mounted in parallel with the main spring. The tunable spring is also used to compensate thermal drift in the new arrangement. We found an unexplained deviation from the 1/f{sup 2} transfer function at resonant frequencies below {approx}100mHz.

  1. Photon attenuation properties of some thorium, uranium and plutonium compounds

    Energy Technology Data Exchange (ETDEWEB)

    Singh, V. P.; Badiger, N. M. [Karnatak University, Department of Physics, Dharwad-580003, Karnataka (India); Vega C, H. R., E-mail: kudphyvps@rediffmail.com [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico)

    2015-10-15

    Mass attenuation coefficients, effective atomic numbers, effective electron densities for nuclear materials; thorium, uranium and plutonium compounds have been studied. The photon attenuation properties for the compounds have been investigated for partial photon interaction processes by photoelectric effect, Compton scattering and pair production. The values of these parameters have been found to change with photon energy and interaction process. The variations of mass attenuation coefficients, effective atomic number and electron density with energy are shown graphically. Moreover, results have shown that these compounds are better shielding and suggesting smaller dimensions. The study would be useful for applications of these materials for gamma ray shielding requirement. (Author)

  2. Ultrasound attenuation estimation using backscattered echoes from multiple sources

    OpenAIRE

    Bigelow, Timothy A.

    2008-01-01

    The objective of this study was to devise an algorithm that can accurately estimate the attenuation along the propagation path (i.e., the total attenuation) from backscattered echoes. It was shown that the downshift in the center frequency of the backscattered ultrasound echoes compared to echoes obtained in a water bath was calculated to have the form Δf=mfo+b after normalizing with respect to the source bandwidth where m depends on the correlation length, b depends on the total attenuation,...

  3. MRI-guided attenuation correction in whole-body PET/MR: assessment of the effect of bone attenuation.

    Science.gov (United States)

    Akbarzadeh, A; Ay, M R; Ahmadian, A; Alam, N Riahi; Zaidi, H

    2013-02-01

    Hybrid PET/MRI presents many advantages in comparison with its counterpart PET/CT in terms of improved soft-tissue contrast, decrease in radiation exposure, and truly simultaneous and multi-parametric imaging capabilities. However, the lack of well-established methodology for MR-based attenuation correction is hampering further development and wider acceptance of this technology. We assess the impact of ignoring bone attenuation and using different tissue classes for generation of the attenuation map on the accuracy of attenuation correction of PET data. This work was performed using simulation studies based on the XCAT phantom and clinical input data. For the latter, PET and CT images of patients were used as input for the analytic simulation model using realistic activity distributions where CT-based attenuation correction was utilized as reference for comparison. For both phantom and clinical studies, the reference attenuation map was classified into various numbers of tissue classes to produce three (air, soft tissue and lung), four (air, lungs, soft tissue and cortical bones) and five (air, lungs, soft tissue, cortical bones and spongeous bones) class attenuation maps. The phantom studies demonstrated that ignoring bone increases the relative error by up to 6.8% in the body and up to 31.0% for bony regions. Likewise, the simulated clinical studies showed that the mean relative error reached 15% for lesions located in the body and 30.7% for lesions located in bones, when neglecting bones. These results demonstrate an underestimation of about 30% of tracer uptake when neglecting bone, which in turn imposes substantial loss of quantitative accuracy for PET images produced by hybrid PET/MRI systems. Considering bones in the attenuation map will considerably improve the accuracy of MR-guided attenuation correction in hybrid PET/MR to enable quantitative PET imaging on hybrid PET/MR technologies.

  4. Effects of experimental warming on fungal disease progress in oilseed rape.

    Science.gov (United States)

    Siebold, Magdalena; von Tiedemann, Andreas

    2013-06-01

    Global warming will influence the growth and development of both crops and pathogens. The aims of this study were to investigate potential effects of future warming on oilseed rape growth and the epidemiology of the three economically important pathogens Verticillium longisporum, Sclerotinia sclerotiorum, and Leptosphaeria maculans (anamorph: Phoma lingam). We utilized climate chambers and a soil warming facility, where treatments represented regional warming scenarios for Lower Saxony, Germany, by 2050 and 2100, and compared results of both approaches on a thermal time scale by calculating degree-days (dd) from day of sowing, December 1st and March 1st until sampling, the latter correlating best with disease progress. Regression analysis showed that plant growth and growth stages in spring responded almost linearly to increasing thermal time until 1000-1500 dd. Colonization of plant tissue by V. longisporum showed an exponential increase when exceeding 1300-1500 dd and reaching plant growth stage BBCH 74/75 (pod development). V. longisporum colonization of plants may be advanced, potentially leading to higher inoculum densities after harvest and increased economic importance of this pathogen under future warming. Sclerotia germination of S. sclerotiorum reached its maximum at 600-900 dd. Advance of these critical degree-days may lead to earlier apothecia production, potentially advancing the infection window, whereas the future importance of S. sclerotiorum may remain constant. Severity of phoma crown canker increased linearly with increasing thermal time, but showed also large variation in response to the warming scenarios, suggesting that factors such as canopy microclimate in fall or leaf shedding over winter may play a bigger role for L. maculans infection and disease severity than higher soil temperatures. Thermal time was a suitable tool to combine and integrate data on biological responses to soil and air temperature increases from climate chamber and field

  5. Psychoneuroendocrine interventions aimed at attenuating immunosenescence: a review

    NARCIS (Netherlands)

    Bauer, M.E.; Muller, G.C.; Correa, B.L.; Vianna, P.; Turner, J.E.; Bosch, J.A.

    2013-01-01

    There is evidence suggesting that immunosenescence can be accelerated by external factors such as chronic stress. Here we review potential psychoneuroendocrine determinants of premature aging of the immune system and discuss available interventions aimed at attenuating immunosenescence. Chronic

  6. ATR kinase regulates its attenuation via PPM1D phosphatase ...

    Indian Academy of Sciences (India)

    Debadrita Bhattacharya

    2018-02-07

    phosphatase regulatory circuitry employed by cells for timely attenuation of protein-phosphorylation signals during transient replication stress, a process that rapidly proliferating cells are constantly subjected to. 2. Material and methods.

  7. Biochanin-A attenuates neuropathic pain in diabetic rats

    Directory of Open Access Journals (Sweden)

    Venkateswarlu Chundi

    2016-10-01

    Conclusion: Biochanin-A demonstrated better efficacy in reversing mechanical allodynia than mechanical hyperalgesia. Biochanin-A could be a good drug candidate for further studies to establish the mechanism of attenuation of neuropathic pain.

  8. Earth/Mars Landing Impact Attenuation Using Foam Project

    Data.gov (United States)

    National Aeronautics and Space Administration — On a previous ICA, a test correlated excel based software tool was developed using the innovative Stress?Energy method to better model impact attenuation using...

  9. Analysis of Surface Wave Attenuation in Mangrove Forests

    Directory of Open Access Journals (Sweden)

    Safwan Hadi

    2003-11-01

    Full Text Available This paper presents an analytical study on surface wave attenuation in mangrove forest using analytical model developed by Massel et.al. (1999. The energy dissipation in the frequency domain is determined by treating the mangrove forest as a random media with certain characteristics using the geometry of mangrove trunks and their locations. Initial nonlinear governing equations are linearized using the concept of minimalization in the stochastic sense and interactions between mangrove trunks and roots have been introduced through the modification of the drag coefficients. To see the effectiveness of the mangrove forest in attenuating wave energy the analytical model was applied to two types of mangrove forest i.e. Rhizophora and Ceriops forests. The resulting rate of wave energy attenuation depends strongly on the density of the mangrove forest, and on diameter of mangrove roots and trunks. More effective wave energy attenuation is shown by Rhizophora.

  10. Natural Attenuation of the Persistent Chemical Warfare Agent ...

    Science.gov (United States)

    Report This project studied the influence of temperature on the natural attenuation of VX from five types of porous/permeable materials: unsealed concrete, plywood, rubber escalator handrail, high density polyethylene (HDPE) plastic, and acoustic ceiling tile.

  11. NAMMA CARBON MONOXIDE BY ATTENUATED LASER TRANSMISSION (COBALT) V1

    Data.gov (United States)

    National Aeronautics and Space Administration — The NAMMA Carbon mOnoxide By Attenuated Laser Transmission (COBALT) dataset includes measurements of the carbon monoxide mixing ratio and derived carbon monoxide...

  12. Evolutionary history and attenuation of myxoma virus on two continents

    National Research Council Canada - National Science Library

    Kerr, Peter J; Ghedin, Elodie; DePasse, Jay V; Fitch, Adam; Cattadori, Isabella M; Hudson, Peter J; Tscharke, David C; Read, Andrew F; Holmes, Edward C

    2012-01-01

    The attenuation of myxoma virus (MYXV) following its introduction as a biological control into the European rabbit populations of Australia and Europe is the canonical study of the evolution of virulence...

  13. Simultaneous reconstruction of activity and attenuation for PET/MR.

    Science.gov (United States)

    Salomon, André; Goedicke, Andreas; Schweizer, Bernd; Aach, Til; Schulz, Volkmar

    2011-03-01

    Medical investigations targeting a quantitative analysis of the position emission tomography (PET) images require the incorporation of additional knowledge about the photon attenuation distribution in the patient. Today, energy range adapted attenuation maps derived from computer tomography (CT) scans are used to effectively compensate for image quality degrading effects, such as attenuation and scatter. Replacing CT by magnetic resonance (MR) is considered as the next evolutionary step in the field of hybrid imaging systems. However, unlike CT, MR does not measure the photon attenuation and thus does not provide an easy access to this valuable information. Hence, many research groups currently investigate different technologies for MR-based attenuation correction (MR-AC). Typically, these approaches are based on techniques such as special acquisition sequences (alone or in combination with subsequent image processing), anatomical atlas registration, or pattern recognition techniques using a data base of MR and corresponding CT images. We propose a generic iterative reconstruction approach to simultaneously estimate the local tracer concentration and the attenuation distribution using the segmented MR image as anatomical reference. Instead of applying predefined attenuation values to specific anatomical regions or tissue types, the gamma attenuation at 511 keV is determined from the PET emission data. In particular, our approach uses a maximum-likelihood estimation for the activity and a gradient-ascent based algorithm for the attenuation distribution. The adverse effects of scattered and accidental gamma coincidences on the quantitative accuracy of PET, as well as artifacts caused by the inherent crosstalk between activity and attenuation estimation are efficiently reduced using enhanced decay event localization provided by time-of-flight PET, accurate correction for accidental coincidences, and a reduced number of unknown attenuation coefficients. First results

  14. Murine immunization by cesium-137 irradiation attenuated Schistosoma mansoni cercariae

    Energy Technology Data Exchange (ETDEWEB)

    Stek, M. Jr.; Minard, P.; Cruess, D.F.

    1984-06-01

    Cesium-137, becoming a more readily available ionizing gamma radiation source for laboratory use, was shown to effectively attenuate Schistosoma mansoni cercariae for vaccine production. In parallel comparison studies with the murine model, cesium-137 attenuated cercariae consistently afforded better protection than did the cobalt-60 prepared vaccine. Dose-response data indicated that the optimal total irradiation with cesium-137 was between 45 and 50 Krad.

  15. Characterizing X-ray Attenuation of Containerized Cargo

    Energy Technology Data Exchange (ETDEWEB)

    Birrer, N. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Divin, C. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Glenn, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martz, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Wang, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-08-02

    X-ray inspection systems can be used to detect radiological and nuclear threats in imported cargo. In order to better understand performance of these systems, the attenuation characteristics of imported cargo need to be determined. This project focused on developing image processing algorithms for segmenting cargo and using x-ray attenuation to quantify equivalent steel thickness to determine cargo density. These algorithms were applied to over 450 cargo radiographs. The results are summarized in this report.

  16. Low energy gamma ray attenuation in multiphase water

    Science.gov (United States)

    Singh, Jag J.; Sprinkle, Danny R.; Eftekhari, Abe

    1990-01-01

    A gauging system is proposed to enable monitoring of slush density, solid-liquid interface, and slush level as well as its flow rate. It is based on the principle that the electromagnetic radiation mass attenuation coefficient of a multiphase chemical compound is constant for all relative phase concentrations. Results showing the essential constancy of mass attenuation coefficients for single-phase water vapor, liquid water, ice, and multiphase mixtures of water/ice are described.

  17. Adaptive attenuation of aliased ground roll using the shearlet transform

    Science.gov (United States)

    Hosseini, Seyed Abolfazl; Javaherian, Abdolrahim; Hassani, Hossien; Torabi, Siyavash; Sadri, Maryam

    2015-01-01

    Attenuation of ground roll is an essential step in seismic data processing. Spatial aliasing of the ground roll may cause the overlap of the ground roll with reflections in the f-k domain. The shearlet transform is a directional and multidimensional transform that separates the events with different dips and generates subimages in different scales and directions. In this study, the shearlet transform was used adaptively to attenuate aliased and non-aliased ground roll. After defining a filtering zone, an input shot record is divided into segments. Each segment overlaps adjacent segments. To apply the shearlet transform on each segment, the subimages containing aliased and non-aliased ground roll, the locations of these events on each subimage are selected adaptively. Based on these locations, mute is applied on the selected subimages. The filtered segments are merged together, using the Hanning function, after applying the inverse shearlet transform. This adaptive process of ground roll attenuation was tested on synthetic data, and field shot records from west of Iran. Analysis of the results using the f-k spectra revealed that the non-aliased and most of the aliased ground roll were attenuated using the proposed adaptive attenuation procedure. Also, we applied this method on shot records of a 2D land survey, and the data sets before and after ground roll attenuation were stacked and compared. The stacked section after ground roll attenuation contained less linear ground roll noise and more continuous reflections in comparison with the stacked section before the ground roll attenuation. The proposed method has some drawbacks such as more run time in comparison with traditional methods such as f-k filtering and reduced performance when the dip and frequency content of aliased ground roll are the same as those of the reflections.

  18. Complement titration by rectilinear attenuance and attempts at its automatization

    Science.gov (United States)

    Satoh, P. S.; Yoshida, T. O.; Fukusima, Y.; Ono, N.; Yoshida, K.; Ito, Y.

    1969-01-01

    Immune haemolysis was determined by rectilinear attenuance at 625 mμ (l = 1.3 mm, 1.25 mm), and the data obtained treated by von Krogh's empirical equation. The C′H50/ml values obtained by the attenuance method had high correlation with those obtained by the conventional photometric method (541 mμ). Automatic complement titration was attempted, as a part of the basic studies on quantitative complement fixation tests. PMID:5386637

  19. Impact of Scattering Model on Disdrometer Derived Attenuation Scaling

    Science.gov (United States)

    Zemba, Michael; Luini, Lorenzo; Nessel, James; Riva, Carlo (Compiler)

    2016-01-01

    NASA Glenn Research Center (GRC), the Air Force Research Laboratory (AFRL), and the Politecnico di Milano (POLIMI) are currently entering the third year of a joint propagation study in Milan, Italy utilizing the 20 and 40 GHz beacons of the Alphasat TDP5 Aldo Paraboni scientific payload. The Ka- and Q-band beacon receivers were installed at the POLIMI campus in June of 2014 and provide direct measurements of signal attenuation at each frequency. Collocated weather instrumentation provides concurrent measurement of atmospheric conditions at the receiver; included among these weather instruments is a Thies Clima Laser Precipitation Monitor (optical disdrometer) which records droplet size distributions (DSD) and droplet velocity distributions (DVD) during precipitation events. This information can be used to derive the specific attenuation at frequencies of interest and thereby scale measured attenuation data from one frequency to another. Given the ability to both predict the 40 GHz attenuation from the disdrometer and the 20 GHz timeseries as well as to directly measure the 40 GHz attenuation with the beacon receiver, the Milan terminal is uniquely able to assess these scaling techniques and refine the methods used to infer attenuation from disdrometer data.In order to derive specific attenuation from the DSD, the forward scattering coefficient must be computed. In previous work, this has been done using the Mie scattering model, however, this assumes a spherical droplet shape. The primary goal of this analysis is to assess the impact of the scattering model and droplet shape on disdrometer derived attenuation predictions by comparing the use of the Mie scattering model to the use of the T-matrix method, which does not assume a spherical droplet. In particular, this paper will investigate the impact of these two scattering approaches on the error of the resulting predictions as well as on the relationship between prediction error and rain rate.

  20. Measuring Attenuation of Optical Fibers with a Photodiode Array (Preprint)

    Science.gov (United States)

    2017-10-23

    display, or disclose the work. 14. ABSTRACT (Maximum 200 words) An innovative approach is proposed and demonstrated for measuring the attenuation of...40292, USA *Corresponding author: frank.hopkins.2@us.af.mil An innovative approach is proposed and demonstrated for measuring the attenuation of light...the open windows on the wafer. The dry film resist remained on the mask through ion implantation but was removed using acetone afterwards. The

  1. Experimental research on the ultrasonic attenuation mechanism of coal

    Science.gov (United States)

    Liu, Guanhua; Liu, Zhentang; Feng, Junjun; Song, Zuokun; Liu, Zhenjing

    2017-06-01

    We studied the ultrasound velocity and attenuation coefficient in coal on the basis of acoustic emission analysis in the time and frequency domains. We also analyzed the mechanism of ultrasound attenuation in coal from a microscopic point of view. Previous research has indicated that the ultrasound velocity and the attenuation coefficient in coal correlate positively and negatively, respectively, with the coal density. In the present study, we found that the acoustic emission characteristics in the time and frequency domain are influenced by the quality of the coal and the fundamental frequency of the ultrasound. For example, the decay time was longer and the amplitude of the received signal was greater in anthracite than in fat coal. Moreover, with increasing fundamental frequency, the decay time decreased and the energy distribution in the transmitted wave became more concentrated around the fundamental frequency. In terms of energy dissipation, coal matrix deformation resulted in a pulling force and caused shear distortion owing to friction, the ultrasonic attenuation in coal is positively affected by the stress induced by ultrasonic waves, which means that a larger strain amplitude would lead to more energy dissipated in coal and an increase of the attenuation coefficient. This was the main cause of ultrasonic attenuation.

  2. Effect of attenuation correction on image quality in emission tomography

    Science.gov (United States)

    Denisova, N. V.; Ondar, M. M.

    2017-10-01

    In this paper, mathematical modeling and computer simulations of myocardial perfusion SPECT imaging are performed. The main factors affecting the quality of reconstructed images in SPECT are anatomical structures, the diastolic volume of a myocardium and attenuation of gamma rays. The purpose of the present work is to study the effect of attenuation correction on image quality in emission tomography. The basic 2D model describing a Tc-99m distribution in a transaxial slice of the thoracic part of a patient body was designed. This model was used to construct four phantoms simulated various anatomical shapes: 2 male and 2 female patients with normal, obese and subtle physique were included in the study. Data acquisition model which includes the effect of non-uniform attenuation, collimator-detector response and Poisson statistics was developed. The projection data were calculated for 60 views in accordance with the standard myocardial perfusion SPECT imaging protocol. Reconstructions of images were performed using the OSEM algorithm which is widely used in modern SPECT systems. Two types of patient's examination procedures were simulated: SPECT without attenuation correction and SPECT/CT with attenuation correction. The obtained results indicate a significant effect of the attenuation correction on the SPECT images quality.

  3. Attenuation Coefficient Estimation of the Healthy Human Thyroid In Vivo

    Science.gov (United States)

    Rouyer, J.; Cueva, T.; Portal, A.; Yamamoto, T.; Lavarello, R.

    Previous studies have demonstrated that attenuation coefficients can be useful towards characterizing thyroid tissues. In this work, ultrasonic attenuation coefficients were estimated from healthy human thyroids in vivo using a clinical scanner. The selected subjects were five young, healthy volunteers (age: 26 ± 6 years old, gender: three females, two males) with no reported history of thyroid diseases, no palpable thyroid nodules, no smoking habits, and body mass index less than 30 kg/m2. Echographic examinations were conducted by a trained sonographer using a SonixTouch system (Ultrasonix Medical Corporation, Richmond, BC) equipped with an L14-5 linear transducer array (nominal center frequency of 10 MHz, transducer footprint of 3.8 cm). Radiofrequency data corresponding to the collected echographic images in both transverse and longitudinal views were digitized at a sampling rate of 40 MHz and processed with Matlab codes (MathWorks, Natick, MA) to estimate attenuation coefficients using the spectral log difference method. The estimation was performed using an analysis bandwidth spanning from 4.0 to 9.0 MHz. The average value of the estimated ultrasonic attenuation coefficients was equal to 1.34 ± 0.15 dB/(cm.MHz). The standard deviation of the estimated average attenuation coefficient across different volunteers suggests a non-negligible inter-subject variability in the ultrasonic attenuation coefficient of the human thyroid.

  4. Significant Attenuation of Lightly Damped Resonances Using Particle Dampers

    Science.gov (United States)

    Smith, Andrew; LaVerde, Bruce; Hunt, Ron; Knight, Joseph Brent

    2015-01-01

    When equipment designs must perform in a broad band vibration environment it can be difficult to avoid resonances that affect life and performance. This is especially true when an organization seeks to employ an asset from a heritage design in a new, more demanding vibration environment. Particle dampers may be used to provide significant attenuation of lightly damped resonances to assist with such a deployment of assets by including only a very minor set of modifications. This solution may be easier to implement than more traditional attenuation schemes. Furthermore, the cost in additional weight to the equipment can be very small. Complexity may also be kept to a minimum, because the particle dampers do not require tuning. Attenuating the vibratory response with particle dampers may therefore be simpler (in a set it and forget it kind of way) than tuned mass dampers. The paper will illustrate the use of an "equivalent resonance test jig" that can assist designers in verifying the potential resonance attenuation that may be available to them during the early trade stages of the design. An approach is suggested for transforming observed attenuation in the jig to estimated performance in the actual service design. KEY WORDS: Particle Damper, Performance in Vibration Environment, Damping, Resonance, Attenuation, Mitigation of Vibration Response, Response Estimate, Response Verification.

  5. Mapping Pn amplitude spreading and attenuation in Asia

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Xiaoning [Los Alamos National Laboratory; Phillips, William S [Los Alamos National Laboratory; Stead, Richard J [Los Alamos National Laboratory

    2010-12-06

    Pn travels most of its path in the mantle lid. Mapping the lateral variation of Pn amplitude attenuation sheds light on material properties and dynamics of the uppermost region of the mantle. Pn amplitude variation depends on the wavefront geometric spreading as well as material attenuation. We investigated Pn geometric spreading, which is much more complex than a traditionally assumed power-law spreading model, using both synthetic and observed amplitude data collected in Asia. We derived a new Pn spreading model based on the formulation that was proposed previously to account for the spherical shape of the Earth (Yang et. al., BSSA, 2007). New parameters derived for the spreading model provide much better correction for Pn amplitudes in terms of residual behavior. Because we used observed Pn amplitudes to construct the model, the model incorporates not only the effect of the Earth's spherical shape, but also the effect of potential upper-mantle velocity gradients in the region. Using the new spreading model, we corrected Pn amplitudes measured at 1, 2, 4 and 6 Hz and conducted attenuation tomography. The resulting Pn attenuation model correlates well with the regional geology. We see high attenuation in regions such as northern Tibetan Plateau and the western Pacific subduction zone, and low attenuation for stable blocks such as Sichuan and Tarim basins.

  6. Changes in ultrasonic attenuation indicative of early myocardial ischemic injury.

    Science.gov (United States)

    Mimbs, J W; O'Donnell, M; Miller, J G; Sobel, B E

    1979-02-01

    This study was designed to determine whether quantitative alterations in ultrasonic attenuation are associated with myocardial changes occurring after acute ischemic injury. Five hundred seventeen regions of myocardium from 41 dogs were studied in vitro at five intervals after coronary occlusion: 15 min, 1 h, 6 h, 24 h, 3 days, and 6 wk. Quantitative indices of ultrasonic attenuation were determined from the measured frequency dependence of the ultrasonic attenuation coefficient characterizing each myocardial region over the range 2-10 MHz. Independent definition of regions of ischemic injury was provided by either creatine kinase depletion or colloidal carbon dye distribution. Results of this study indicate that ischemic myocardial regions investigated 15 min to 24 h after coronary occlusion demonstrated ultrasonic attenuation significantly decreased from nonischemic regions (P less than 0.05). In contrast, ultrasonic attenuation was significantly increased in zones of ischemia or infarction investigated at 3 days and 6 wk after coronary occlusion (P less than 0.05 and P less than 0.01, respectively). These results indicate that altered attenuation of transmitted ultrasound by myocardium in vitro is an early manifestation of ischemia.

  7. Inversion of acoustic waveforms for velocity and attenuation

    Science.gov (United States)

    Sun, Xinhua

    In this dissertation, I present some new schemes and techniques for processing of acoustic waveform data. New objective functions are developed for waveform inversion. I use synthetic acoustic borehole waveform data to demonstrate their novel features. These schemes require neither prior deconvolution nor knowledge of the source- receiver wavelet. The most powerful of them is the fourwise processor, which is applicable to data sets from multiple shots and receivers even when each shot has a different unknown signature and each receiver has a different unknown impulse response. I apply this scheme to inversion for shear wave velocity from the ODP sonic data measured by an LSS tool, containing two uncalibrated transmitters and receivers. A 3-D search of waveform inversion gives stable results of formation S-wave velocity inverted from the monopole sonic data in a slow formation. In addition, I develop new techniques to extract P- and S-wave attenuation from sonic logging data. The success of the techniques lies in the separation of attenuation-related wave attributes from other effects unrelated to attenuation. The wave attributes related to borehole diameter, formation density, and velocity changes are removed by use of synthetic sonograms. The novelty of the techniques is first to use a single receiver data set to extract a relative attenuation profile, then to correct it to absolute attenuation using multiple receiver data sets. The techniques are applicable to both monopole and dipole waveform log data for either P- or S-wave attenuation.

  8. Sensory attenuation for jointly-produced action effects

    Directory of Open Access Journals (Sweden)

    Janeen Dawn Loehr

    2013-04-01

    Full Text Available Successful joint action often requires people to distinguish between their own and others’ contributions to a shared goal. One mechanism that is thought to underlie a self-other distinction is sensory attenuation, whereby the sensory consequences of one’s own actions are reduced compared to other sensory events. Previous research has shown that the auditory N1 event-related potential (ERP response is reduced for self-generated compared to externally-generated tones. The current study examined whether attenuation also occurs for jointly-generated tones, which require two people to coordinate their actions to produce a single tone. ERP responses were measured when participants generated tones alone (tone onset immediately followed the participant’s button press or with a partner (tone onset immediately followed the participant’s or the partner’s button press, whichever occurred second. N1 attenuation was smaller for jointly-generated tones compared to self-generated tones. For jointly-generated tones, greater delays between the participant’s and the partner’s button presses were associated with reduced attenuation; moreover, only trials in which there was no delay between the participant’s press and tone onset showed attenuation, whereas trials in which there were delays did not show attenuation. These findings indicate that people differentiate between their own and another person’s contributions to a joint action at the sensorimotor level, even when they must act together to produce a single, shared effect.

  9. Modeling Dust Attenuation Laws in Galaxies with Cosmological Zoom Simulations

    Science.gov (United States)

    Narayanan, Desika

    2017-08-01

    The attenuation of star light in galaxies by dust imposes a major uncertainty in the derivation of galaxy physical properties. As we show in this proposal, for example, incorrect assumptions about attenuation laws in SED fitting can result in errors of 0.3 dex in the derived M* and SFR from galaxies. While HST observations have revealed variations in inferred dust attenuation laws, we currently lack a comprehensive theory for how and why attenuation curves vary within and between galaxies. Complicating the issue are both the necessity for 3D radiative transfer modeling (to capture absorption and scattering), as well as a model for the geometry of luminous sources and dust in galaxies. To address this, we propose to conduct a large series of high-resolution cosmological zoom galaxy formation simulations in which we super-resolve giant clouds in the interstellar medium. These simulations will be coupled with a novel 3D dust radiative transfer package in order to derive theoretical dust attenuation curves. Our main scientific goals are twofold: (1) to derive the first ever connection between global properties of galaxies and their dust attenuation laws; and (2) to build better SED fitting techniques in order to improve the accuracy of physical properties inferred from galaxy SED fitting. All of our simulation results, population synthesis codes, and SED fitting codes will be made publicly available.

  10. Novel point mutations attenuate autotaxin activity

    Directory of Open Access Journals (Sweden)

    Stracke Mary L

    2009-02-01

    Full Text Available Abstract Background The secreted enzyme autotaxin (ATX stimulates tumor cell migration, tumorigenesis, angiogenesis, and metastasis. ATX hydrolyzes nucleotides, but its hydrolysis of lysophospholipids to produce lysophosphatidic acid (LPA accounts for its biological activities. ATX has been identified only as a constitutively active enzyme, and regulation of its activity is largely unexplored. In spite of its presence in plasma along with abundant putative substrate LPC, the product LPA is found in plasma at unexpectedly low concentrations. It is plausible that the LPA-producing activity of ATX is regulated by its expression and by access to substrate(s. For this reason studying the interaction of enzyme with substrate is paramount to understanding the regulation of LPA production. Results In this study we determine ATX hydrolytic activities toward several artificial and natural substrates. Two novel point mutations near the enzyme active site (H226Q and H434Q confer attenuated activity toward all substrates tested. The Vmax for LPC compounds depends upon chain length and saturation; but this order does not differ among wild type and mutants. However the mutant forms show disproportionately low activity toward two artificial substrates, pNpTMP and FS-3. The mutant forms did not significantly stimulate migration responses at concentrations that produced a maximum response for WT-ATX, but this defect could be rescued by inclusion of exogenous LPC. Conclusion H226Q-ATX and H434Q-ATX are the first point mutations of ATX/NPP2 demonstrated to differentially impair substrate hydrolysis, with hydrolysis of artificial substrates being disproportionately lower than that of LPC. This implies that H226 and H434 are important for substrate interaction. Assays that rely on hydrolyses of artificial substrates (FS-3 and pNpTMP, or that rely on hydrolysis of cell-derived substrate, might fail to detect certain mutated forms of ATX that are nonetheless capable of

  11. Efficacy of Rugby Headgear in Attenuating Repetitive Linear Impact Forces

    Science.gov (United States)

    Knouse, Carissa L.; Gould, Trenton E.; Caswell, Shane V.

    2003-01-01

    Objective: To determine the effectiveness of rugby headgear and the effect of impact site and headgear type on attenuating repetitive linear impact forces. Design and Setting: We obtained 10 headgear of 2 different types (n = 20) from 2 popular manufacturers: type I was Honeycomb headgear and type II was Vanguard headgear. Both headgear types were approved by the International Rugby Board. Headgear were tested according to National Operating Committee on Standards for Athletic Equipment protocols with one modification. The headgear were dropped from a height of 30 cm according to the International Rugby Board standards. Headgear were tested at a National Athletic Equipment Reconditioners Association facility. Measurements: We recorded peak acceleration of gravity (g) and Gadd Severity Index readings for each impact. The design of the study was 4 one-way, within-subjects, repeated-measures analyses of variance with alpha = .05. Descriptive statistics were calculated for all categoric variables. Results: Peak g and Gadd Severity Index increased with repetitive impacts, resulting in a headgear's decreased ability to attenuate linear impact forces. Attenuation differed significantly between headgear type I and type II at both impact sites and between the parietal-lateral and occipital impact sites for both headgear types. Conclusions: The headgear initially attenuated impact forces from a drop height of 30 cm. However, over 10 drops, both headgear decreased in their ability to attenuate repetitive linear impact forces. Decreased attenuation in the occipital region as well as significant differences in attenuation abilities between headgear types support the need for further investigation to examine the efficacy of rugby headgear. PMID:14737216

  12. Attenuation of trace organic compounds (TOrCs) inbioelectrochemical systems

    KAUST Repository

    Werner, Craig M.

    2015-04-01

    Microbial fuel cells (MFCs) and microbial electrolysis cells (MECs) are two types of microbial bioelectrochemical systems (BESs) that use microorganisms to convert chemical energy in wastewaters into useful energy products such as (bio)electricity (MFC) or hydrogen gas (MEC). These two systems were evaluated for their capacity to attenuate trace organic compounds (TOrCs), commonly found in municipal wastewater, under closed circuit (current generation) and open circuit (no current generation) conditions, using acetate as the carbon source. A biocide was used to evaluate attenuation in terms of biotransformation versus sorption. The difference in attenuation observed before and after addition of the biocide represented biotransformation, while attenuation after addition of a biocide primarily indicated sorption. Attenuation of TOrCs was similar in MFCs and MECs for eight different TOrCs, except for caffeine and trimethoprim where slightly higher attenuation was observed in MECs. Electric current generation did not enhance attenuation of the TOrCs except for caffeine, which showed slightly higher attenuation under closed circuit conditions in both MFCs and MECs. Substantial sorption of the TOrCs occurred to the biofilm-covered electrodes, but no consistent trend could be identified regarding the physico-chemical properties of the TOrCs tested and the extent of sorption. The octanol-water distribution coefficient at pH 7.4 (log DpH 7.4) appeared to be a reasonable predictor for sorption of some of the compounds (carbamazepine, atrazine, tris(2-chloroethyl) phosphate and diphenhydramine) but not for others (N,N-Diethyl-meta-toluamide). Atenolol also showed high levels of sorption despite being the most hydrophilic in the suite of compounds studied (log DpH 7.4=-1.99). Though BESs do not show any inherent advantages over conventional wastewater treatment, with respect to TOrC removal, overall removals in BESs are similar to that reported for conventional wastewater

  13. Mechanisms of temperature sensitivity of attenuated Urabe mumps virus.

    Science.gov (United States)

    Schinkel, Stephanie C Burke; Rubin, Steven; Wright, Kathryn E

    2017-01-02

    Temperature sensitivity is a phenotype often associated with attenuation of viruses. Previously, we purified several mumps variants from an incompletely attenuated Urabe strain live attenuated vaccine. Here we characterize one isolate that is sensitive to growth at high temperature. This virus was attenuated in a small animal model of mumps virulence, and we identified unique coding substitutions in the hemagglutinin-neuraminidase (HN), the viral polymerase (L) gene, and a non-coding substitution close to the anti-genome promoter sequences. At the non-permissive temperature, transcription of viral mRNAs and production of the replication intermediate were reduced compared to events at the permissive temperature and to a non-ts virulent Urabe virus. As well, synthesis of viral proteins was also reduced at the higher temperature. While the actual sequence substitutions in the ts virus were unique, the pattern of substitutions in HN, L and genome end sequences is similar to another attenuated Urabe virus previously described by us. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Radar attenuation and temperature within the Greenland Ice Sheet

    Science.gov (United States)

    MacGregor, Joseph A; Li, Jilu; Paden, John D; Catania, Ginny A; Clow, Gary D.; Fahnestock, Mark A; Gogineni, Prasad S.; Grimm, Robert E.; Morlighem, Mathieu; Nandi, Soumyaroop; Seroussi, Helene; Stillman, David E

    2015-01-01

    The flow of ice is temperature-dependent, but direct measurements of englacial temperature are sparse. The dielectric attenuation of radio waves through ice is also temperature-dependent, and radar sounding of ice sheets is sensitive to this attenuation. Here we estimate depth-averaged radar-attenuation rates within the Greenland Ice Sheet from airborne radar-sounding data and its associated radiostratigraphy. Using existing empirical relationships between temperature, chemistry, and radar attenuation, we then infer the depth-averaged englacial temperature. The dated radiostratigraphy permits a correction for the confounding effect of spatially varying ice chemistry. Where radar transects intersect boreholes, radar-inferred temperature is consistently higher than that measured directly. We attribute this discrepancy to the poorly recognized frequency dependence of the radar-attenuation rate and correct for this effect empirically, resulting in a robust relationship between radar-inferred and borehole-measured depth-averaged temperature. Radar-inferred englacial temperature is often lower than modern surface temperature and that of a steady state ice-sheet model, particularly in southern Greenland. This pattern suggests that past changes in surface boundary conditions (temperature and accumulation rate) affect the ice sheet's present temperature structure over a much larger area than previously recognized. This radar-inferred temperature structure provides a new constraint for thermomechanical models of the Greenland Ice Sheet.

  15. DEVELOPEMENT OF A LIGHT ATTENUATOR BASED ON GLASSY REFLECTIONS

    Directory of Open Access Journals (Sweden)

    K. Ferria

    2015-07-01

    Full Text Available The light intensity control of a luminous source is a very important operation in many optical applications. Several types of light attenuator exploiting different optical phenomena like diffraction, absorption, and reflection exist and they differ principally in the maximum attenuation rate, the control range, the sensitivity and the spectral band. In the presented work, we have developed and designed a light attenuator based on the progressive decrease of the transmitted light intensity, when it undergoes multiple vitreous reflections across eight plates glasses arranged in a roof shape. Several tests were carried out using a laser light as a source. We have shown that the attenuation rate can be controlled by the choice of the incidence angle on the glasses slides, in addition we have confirmed, for the case of perpendicular polarization of the laser light, that the attenuation obeys to a linear function. The obtained results are very close to those predicted theoretically.

  16. Wild type measles virus attenuation independent of type I IFN

    Directory of Open Access Journals (Sweden)

    Horvat Branka

    2008-02-01

    Full Text Available Abstract Background Measles virus attenuation has been historically performed by adaptation to cell culture. The current dogma is that attenuated virus strains induce more type I IFN and are more resistant to IFN-induced protection than wild type (wt. Results The adaptation of a measles virus isolate (G954-PBL by 13 passages in Vero cells induced a strong attenuation of this strain in vivo. The adapted virus (G954-V13 differs from its parental strain by only 5 amino acids (4 in P/V/C and 1 in the M gene. While a vaccine strain, Edmonston Zagreb, could replicate equally well in various primate cells, both G954 strains exhibited restriction to the specific cell type used initially for their propagation. Surprisingly, we observed that both G954 strains induced type I IFN, the wt strain inducing even more than the attenuated ones, particularly in human plasmacytoid Dendritic Cells. Type I IFN-induced protection from the infection of both G954 strains depended on the cell type analyzed, being less efficient in the cells used to grow the viral strain. Conclusion Thus, mutations in M and P/V/C proteins can critically affect MV pathogenicity, cellular tropism and lead to virus attenuation without interfering with the α/β IFN system.

  17. Pentoxifylline Attenuates Cardiac Remodeling Induced by Tobacco Smoke Exposure

    Energy Technology Data Exchange (ETDEWEB)

    Minicucci, Marcos; Oliveira, Fernando; Santos, Priscila; Polegato, Bertha; Roscani, Meliza; Fernandes, Ana Angelica; Lustosa, Beatriz; Paiva, Sergio; Zornoff, Leonardo; Azevedo, Paula, E-mail: paulasa@fmb.unesp.br [Faculdade de Medicina de Botucatu, Universidade Estadual Paulista, São Paulo, SP (Brazil)

    2016-05-15

    Tobacco smoke exposure is an important risk factor for cardiac remodeling. Under this condition, inflammation, oxidative stress, energy metabolism abnormalities, apoptosis, and hypertrophy are present. Pentoxifylline has anti‑inflammatory, anti-apoptotic, anti-thrombotic and anti-proliferative properties. The present study tested the hypothesis that pentoxifylline would attenuate cardiac remodeling induced by smoking. Wistar rats were distributed in four groups: Control (C), Pentoxifylline (PX), Tobacco Smoke (TS), and PX-TS. After two months, echocardiography, invasive blood pressure measurement, biochemical, and histological studies were performed. The groups were compared by two-way ANOVA with a significance level of 5%. TS increased left atrium diameter and area, which was attenuated by PX. In the isolated heart study, TS lowered the positive derivate (+dp/dt), and this was attenuated by PX. The antioxidants enzyme superoxide dismutase and glutathione peroxidase were decreased in the TS group; PX recovered these activities. TS increased lactate dehydrogenase (LDH) and decreased 3-hydroxyacyl Coenzyme A dehydrogenases (OH-DHA) and citrate synthase (CS). PX attenuated LDH, 3-OH-DHA and CS alterations in TS-PX group. TS increased IL-10, ICAM-1, and caspase-3. PX did not influence these variables. TS induced cardiac remodeling, associated with increased inflammation, oxidative stress, apoptosis, and changed energy metabolism. PX attenuated cardiac remodeling by reducing oxidative stress and improving cardiac bioenergetics, but did not act upon cardiac cytokines and apoptosis.

  18. Is non-attenuation-corrected PET inferior to body attenuation-corrected PET or PET/CT in lung cancer?

    Energy Technology Data Exchange (ETDEWEB)

    Maintas, Dimitris [CMN, Hopital Pneumocardiologique de Lyon, 69394 Lyon Cedex (France)]. E-mail: maintas@otenet.gr; Houzard, Claire [CMN, Hopital Pneumocardiologique de Lyon, 69394 Lyon Cedex (France); Ksyar, Rachid [CMN, Hopital Pneumocardiologique de Lyon, 69394 Lyon Cedex (France); Mognetti, Thomas [Anticancer Center Leon Berard, Nuclear Medicine Department, Lyon (France); Maintas, Catherine [Institute of Isotopic Studies, Distomou 5-7, Maroussi (Greece); Scheiber, Christian [CMN, Hopital Pneumocardiologique de Lyon, 69394 Lyon Cedex (France); Itti, Roland [CMN, Hopital Pneumocardiologique de Lyon, 69394 Lyon Cedex (France)

    2006-12-20

    It is considered that one of the great strengths of PET imaging is the ability to correct for body attenuation. This enables better lesion uptake quantification and quality of PET images. The aim of this work is to compare the sensitivity of non-attenuation-corrected (NAC) PET images, the gamma photons (GPAC) and CT attenuation-corrected (CTAC) images in detecting and staging of lung cancer. We have studied 66 patients undergoing PET/CT examinations for detecting and staging NSC lung cancer. The patients were injected with 18-FDG; 5 MBq/kg under fasting conditions and examination was started 60 min later. Transmission data were acquired by a spiral CT X-ray tube and by gamma photons emitting Cs-137l source and were used for the patient body attenuation correction without correction for respiratory motion. In 55 of 66 patients we performed both attenuation correction procedures and in 11 patients only CT attenuation correction. In seven patients with solitary nodules PET was negative and in 59 patients with lung cancer PET/CT was positive for pulmonary or other localization. In the group of 55 patients we found 165 areas of focal increased 18-FDG uptake in NAC, 165 in CTAC and 164 in GPAC PET images.In the patients with only CTAC we found 58 areas of increased 18-FDG uptake on NAC and 58 areas lesions on CTAC. In the patients with positive PET we found 223 areas of focal increased uptake in NAC and 223 areas in CTAC images. The sensitivity of NAC was equal to the sensitivity of CTAC and GPAC images. The visualization of peripheral lesions was better in NAC images and the lesions were better localized in attenuation-corrected images. In three lesions of the thorax the localization was better in GPAC and fused images than in CTAC images.

  19. Development of a human live attenuated West Nile infectious DNA vaccine: Suitability of attenuating mutations found in SA14-14-2 for WN vaccine design

    Energy Technology Data Exchange (ETDEWEB)

    Yamshchikov, Vladimir, E-mail: yaximik@gmail.com; Manuvakhova, Marina; Rodriguez, Efrain

    2016-01-15

    Direct attenuation of West Nile (WN) virus strain NY99 for the purpose of vaccine development is not feasible due to its high virulence and pathogenicity. Instead, we created highly attenuated chimeric virus W1806 with the serological identity of NY99. To further attenuate W1806, we investigated effects of mutations found in Japanese encephalitis virus vaccine SA14-14-2. WN viruses carrying all attenuating mutations lost infectivity in mammalian, but not in mosquito cells. No single reversion restored infectivity in mammalian cells, although increased infectivity in mosquito cells was observed. To identify a subset of mutations suitable for further attenuation of W1806, we analyzed effects of E{sub 138}K and K{sub 279}M changes on virulence, growth properties, and immunogenicity of derivatized W956, from which chimeric W1806 inherited its biological properties and attenuation profile. Despite strong dominant attenuating effect, introduction of only two mutations was not sufficient for attenuating W1806 to the safety level acceptable for human use. - Highlights: • Further attenuation of a WN vaccine precursor is outlined. • Effect of SA14-14-2 attenuating mutations is tested. • Mechanism of attenuation is proposed and illustrated. • The need for additional attenuating mutations is justified.

  20. Organic amorphous fluoropolymer membrane for variable optical attenuator applications

    Science.gov (United States)

    Yeh, Yu-Wei; Chiu, Chen-Wei E.; Su, Guo-Dung J.

    2006-07-01

    The paper describes the design, fabrication and testing of a MEMS (micro-electro-mechanical systems) variable optical attenuator (VOA) made from an organic fluoropolymer thin film. The optical attenuation is achieved by changing the radius of curvature of the organic thin film by actuating a pneumatic force. The size of the organic polymer membrane is 4 mm × 4 mm and the measured centre displacement of the organic membrane is as large as 57 µm without any plastic deformation. The mechanical deformation of the fluoropolymer membrane can be simulated by finite element method (FEM) and the optical coupling efficiency is calculated based on the coherent optical transfer function (OTF) of the deformed membrane. The experimental results show that the attenuation range can achieve 25 dB at the wavelength of 1550 nm, which agrees well with the theoretical calculation. The measured wavelength dependence loss is less than 0.5 dB.

  1. Working memory load attenuates emotional enhancement in recognition memory

    Directory of Open Access Journals (Sweden)

    Ewa Aurelia Miendlarzewska

    2013-03-01

    Full Text Available Emotionally arousing stimuli are perceived and remembered better than neutral stimuli. Under threat, this negativity bias is further increased. We investigated whether working memory load can attenuate incidental memory for emotional images. Two groups of participants performed the N-back task with two working memory load levels. In one group, we induced anxiety using a threat-of-shock paradigm to increase attentional processing of negative information. During task performance we incidentally and briefly flashed emotional distracter images which prolonged response times in both load conditions. A subsequent unannounced immediate recognition memory test revealed that when load at exposure had been low, recognition was better for negative items in both participant groups. This enhancement, however, was attenuated under high load, leaving performance on neutral items unchanged regardless of the threat-of-shock manipulation. We conclude that both in threat and in normal states working memory load at exposure can attenuate immediate emotional memory enhancement.

  2. Random noise attenuation using an improved anisotropic total variation regularization

    Science.gov (United States)

    Gemechu, Diriba; Yuan, Huan; Ma, Jianwei

    2017-09-01

    In seismic data processing, attenuation of random noise from the observed data is the basic step which improves the signal-to-noise ratio (SNR) of seismic data. In this paper, we proposed an anisotropic total bounded variation regularization approach to attenuate noise. An improved constraint convex optimization model is formulated for this approach and then the split Bregman algorithm is used to solve the optimization model. Generalized cross validation (GCV) technique is used to estimate the regularization parameter. Synthetic and real seismic data are considered to show the out performance of the proposed method in terms of event-preserving denoising, in comparison with FX deconvolution, shearlet hard thresholding, and anisotropic total variation methods. The numerical results indicate that the proposed method effectively attenuates random noise by preserving the structure and important features of seismic data.

  3. Statistical modeling of optical attenuation measurements in continental fog conditions

    Science.gov (United States)

    Khan, Muhammad Saeed; Amin, Muhammad; Awan, Muhammad Saleem; Minhas, Abid Ali; Saleem, Jawad; Khan, Rahimdad

    2017-03-01

    Free-space optics is an innovative technology that uses atmosphere as a propagation medium to provide higher data rates. These links are heavily affected by atmospheric channel mainly because of fog and clouds that act to scatter and even block the modulated beam of light from reaching the receiver end, hence imposing severe attenuation. A comprehensive statistical study of the fog effects and deep physical understanding of the fog phenomena are very important for suggesting improvements (reliability and efficiency) in such communication systems. In this regard, 6-months real-time measured fog attenuation data are considered and statistically investigated. A detailed statistical analysis related to each fog event for that period is presented; the best probability density functions are selected on the basis of Akaike information criterion, while the estimates of unknown parameters are computed by maximum likelihood estimation technique. The results show that most fog attenuation events follow normal mixture distribution and some follow the Weibull distribution.

  4. Fiber movements and sound attenuation in glass wool

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1999-01-01

    Propagation of a plane harmonic sound wave in fiber materials such as glass wool is studied theoretically and experimentally. Wave equations are set up that take into account the movement of the fiber skeleton. The attenuation of the sound wave in slabs of glass wool was calculated and measured....... The main new result is that the experimental attenuation at low-frequency propagating wave is lower when the fibers move. For wave with frequency 100 Hz in glass wool of density 20 kg/m3, the attenuation of a layer of thickness 0.20 m is 4 dB if the fibers move, and 12 dB if they do not move...

  5. Iterative methods for photoacoustic tomography in attenuating acoustic media

    Science.gov (United States)

    Haltmeier, Markus; Kowar, Richard; Nguyen, Linh V.

    2017-11-01

    The development of efficient and accurate reconstruction methods is an important aspect of tomographic imaging. In this article, we address this issue for photoacoustic tomography. To this aim, we use models for acoustic wave propagation accounting for frequency dependent attenuation according to a wide class of attenuation laws that may include memory. We formulate the inverse problem of photoacoustic tomography in attenuating medium as an ill-posed operator equation in a Hilbert space framework that is tackled by iterative regularization methods. Our approach comes with a clear convergence analysis. For that purpose we derive explicit expressions for the adjoint problem that can efficiently be implemented. In contrast to time reversal, the employed adjoint wave equation is again damping and, thus has a stable solution. This stability property can be clearly seen in our numerical results. Moreover, the presented numerical results clearly demonstrate the efficiency and accuracy of the derived iterative reconstruction algorithms in various situations including the limited view case.

  6. Consideration of natural attenuation. In remedation contaminated sites

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2011-04-15

    Upon the proposal submitted by ist Standing committee 5 (Contaminated Sites Committee - ALA) the Federal / State Working Group on Soil protection employed an ad hoc subcommittee dealing with considering natural attenuation in remediating contaminated sites and preparing an inter-State position paper. In the present position paper the way how to consider natural attenuation in practical remediation of contaminated sites is described. The systematic approach outlined allows an understandable decision-finding. A way is shown how the competent soil protection authorities may exercise discretion and in the framework of checking the appropriateness of measures may decide on the implementation of MNA based on a MNA concept (MNA = monitored natural attenuation). It is, however, also explained that when carrying out MNA a decision always made in an individual case is concerned which should be made in a close agreement between the obligated party and the authority.

  7. Spinon phonon interaction and ultrasonic attenuation in quantum spin liquids.

    Science.gov (United States)

    Zhou, Yi; Lee, Patrick A

    2011-02-04

    Several experimental candidates for quantum spin liquids have been discovered in the past few years which appear to support gapless fermionic S=1/2 excitations called spinons. The spinons may form a Fermi sea coupled to a U(1) gauge field, and may undergo a pairing instability. We show that despite being charge neutral, the spinons couple to phonons in exactly the same way that electrons do in the long wavelength limit. Therefore, we can use sound attenuation to measure the spinon mass and lifetime. Furthermore, transverse ultrasonic attenuation is a direct probe of the onset of pairing because the Meissner effect of the gauge field causes a "rapid fall" of the attenuation at T(c) in addition to the reduction due to the opening of the energy gap. This phenomenon, well known in clean superconductors, may reveal the existence of the U(1) gauge field.

  8. MTBE, TBA, and TAME attenuation in diverse hyporheic zones

    Science.gov (United States)

    Landmeyer, J.E.; Bradley, P.M.; Trego, D.A.; Hale, K.G.; Haas, J.E.

    2010-01-01

    Groundwater contamination by fuel-related compounds such as the fuel oxygenates methyl tert-butyl ether (MTBE), tert-butyl alcohol (TBA), and tert-amyl methyl ether (TAME) presents a significant issue to managers and consumers of groundwater and surface water that receives groundwater discharge. Four sites were investigated on Long Island, New York, characterized by groundwater contaminated with gasoline and fuel oxygenates that ultimately discharge to fresh, brackish, or saline surface water. For each site, contaminated groundwater discharge zones were delineated using pore water geochemistry data from 15 feet (4.5 m) beneath the bottom of the surface water body in the hyporheic zone and seepage-meter tests were conducted to measure discharge rates. These data when combined indicate that MTBE, TBA, and TAME concentrations in groundwater discharge in a 5-foot (1.5-m) thick section of the hyporheic zone were attenuated between 34% and 95%, in contrast to immeasurable attenuation in the shallow aquifer during contaminant transport between 0.1 and 1.5 miles (0.1 to 2.4 km). The attenuation observed in the hyporheic zone occurred primarily by physical processes such as mixing of groundwater and surface water. Biodegradation also occurred as confirmed in laboratory microcosms by the mineralization of U- 14C-MTBE and U- 14C-TBA to 14CO2 and the novel biodegradation of U- 14C-TAME to 14CO2 under oxic and anoxic conditions. The implication of fuel oxygenate attenuation observed in diverse hyporheic zones suggests an assessment of the hyporheic zone attenuation potential (HZAP) merits inclusion as part of site assessment strategies associated with monitored or engineered attenuation. ?? 2009 National Ground Water Association.

  9. Seismic velocity, attenuation and rheology of the upper mantle

    Science.gov (United States)

    Anderson, D. L.; Minster, J. B.

    1980-01-01

    Seismic and rheological properties of the upper mantle in the vicinity of the low-velocity zone are expressed in terms of relaxation by dislocation glide. Dislocation bowing in the glide plane explains seismic velocities and attenuation. Climbing at higher stresses for longer periods of time give the observed viscosity, and explain the low velocity and high temperature attenuation found at seismic frequencies. Due to differing parameters, separate terms for thermal, seismic and rheological lithospheres are proposed. All three lithospheres, however, are related and are functions of temperature, and must be specified by parameters such as period, stress, and stress duration.

  10. Note: Attenuation motion of acoustically levitated spherical rotor

    Science.gov (United States)

    Lü, P.; Hong, Z. Y.; Yin, J. F.; Yan, N.; Zhai, W.; Wang, H. P.

    2016-11-01

    Here we observe the attenuation motion of spherical rotors levitated by near-field acoustic radiation force and analyze the factors that affect the duration time of free rotation. It is found that the rotating speed of freely rotating rotor decreases exponentially with respect to time. The time constant of exponential attenuation motion depends mainly on the levitation height, the mass of rotor, and the depth of concave ultrasound emitter. Large levitation height, large mass of rotor, and small depth of concave emitter are beneficial to increase the time constant and hence extend the duration time of free rotation.

  11. Homogeneous Magnetic Field Source For Attenuated Total Reflection

    Directory of Open Access Journals (Sweden)

    Lesňák Michal

    2014-07-01

    Full Text Available The paper is focused on the study of two-dimensional magnetic field distribution used for an analysis of samples containing magnetically active films by means of the Attenuated Total Reflection (ATR method. The design of a proposed electromagnet and the magnetic field model computation are presented together with the results obtained from magnetic field distribution measurement. The ATR method can provide information about a thin film thickness, refractive index, and attenuation in addition to the perfunctory coupling of an optical wave into and off a waveguide [1, 2]. The prism coupling conditions are determined for magnetic structures with induced anisotropy.

  12. Regularized Image Reconstruction for Ultrasound Attenuation Transmission Tomography

    Directory of Open Access Journals (Sweden)

    I. Peterlik

    2008-06-01

    Full Text Available The paper is focused on ultrasonic transmission tomography as a potential medical imaging modality, namely for breast cancer diagnosis. Ultrasound attenuation coefficient is one of the tissue parameters which are related to the pathological tissue state. A technique to reconstruct images of attenuation distribution is presented. Furthermore, an alternative to the commonly used filtered backprojection or algebraic reconstruction techniques is proposed. It is based on regularization of the image reconstruction problem which imposes smoothness in the resulting images while preserving edges. The approach is analyzed on synthetic data sets. The results show that it stabilizes the image restoration by compensating for main sources of estimation errors in this imaging modality.

  13. Emission-based estimation of lung attenuation coefficients for attenuation correction in time-of-flight PET/MR

    Science.gov (United States)

    Mehranian, Abolfazl; Zaidi, Habib

    2015-06-01

    In standard segmentation-based MRI-guided attenuation correction (MRAC) of PET data on hybrid PET/MRI systems, the inter/intra-patient variability of linear attenuation coefficients (LACs) is ignored owing to the assignment of a constant LAC to each tissue class. This can lead to PET quantification errors, especially in the lung regions. In this work, we aim to derive continuous and patient-specific lung LACs from time-of-flight (TOF) PET emission data using the maximum likelihood reconstruction of activity and attenuation (MLAA) algorithm. The MLAA algorithm was constrained for estimation of lung LACs only in the standard 4-class MR attenuation map using Gaussian lung tissue preference and Markov random field smoothness priors. MRAC maps were derived from segmentation of CT images of 19 TOF-PET/CT clinical studies into background air, lung, soft tissue and fat tissue classes, followed by assignment of predefined LACs of 0, 0.0224, 0.0864 and 0.0975 cm-1, respectively. The lung LACs of the resulting attenuation maps were then estimated from emission data using the proposed MLAA algorithm. PET quantification accuracy of MRAC and MLAA methods was evaluated against the reference CT-based AC method in the lungs, lesions located in/near the lungs and neighbouring tissues. The results show that the proposed MLAA algorithm is capable of retrieving lung density gradients and compensate fairly for respiratory-phase mismatch between PET and corresponding attenuation maps. It was found that the mean of the estimated lung LACs generally follow the trend of the reference CT-based attenuation correction (CTAC) method. Quantitative analysis revealed that the MRAC method resulted in average relative errors of  -5.2   ±   7.1% and  -6.1   ±   6.7% in the lungs and lesions, respectively. These were reduced by the MLAA algorithm to  -0.8   ±   6.3% and  -3.3   ±   4.7%, respectively. In conclusion, we demonstrated

  14. Whole-body PET/MRI: The effect of bone attenuation during MR-based attenuation correction in oncology imaging

    DEFF Research Database (Denmark)

    Aznar, M.C.; Sersar, Rachida; Saabye, J.

    2014-01-01

    Purpose: In combined PET/MRI standard PET attenuation correction (AC) is based on tissue segmentation following dedicated MR sequencing and, typically, bone tissue is not represented. We evaluate PET quantification in whole-body (WB)-PET/MRI following MR-AC without considering bone attenuation...... and then investigate different strategies to account for bone tissue in clinical PET/MR imaging. To this purpose, bone tissue representation was extracted from separate CT images, and different bone representations were simulated from hypothetically derived MR-based bone classifications. Methods: Twenty oncology...

  15. Seismic hazard scenario and attenuation model of the Garhwal ...

    Indian Academy of Sciences (India)

    137 13–29. Fukushima Y and Tanaka T 1990 A new attenuation relation for peak horizontal ground acceleration of strong ground motion in Japan; Bull. Seismol. Soc. Am. 80 757–783. Gumbel E J 1958 Statistics of Extremes (New York: Columbia University Press). Hanks T C and Kanamori H 1979 A moment magnitude.

  16. Synthetic Chemicals with Potential for Natural Attenuation (Postprint)

    Science.gov (United States)

    2012-07-01

    purposes of natural attenuation. In contrast, aerobic bacteria able to grow on nitrobenzene, nitrotoluenes , dinitrotoluenes, dinitrobenzene, nitrobenzoates...of the isomeric nitro compounds can be prob- lematic for microbial degradation. For example, the industrial synthesis of polyurethane produces large...September, 1996 (Spain, 1996). • Vinyl chloride • 1 ,2-Dibromoethane • Polychlorinated biphenyls • Nitrobenzene • Nitrotoluenes • Dinitrotoluenes

  17. 49 CFR 227.117 - Hearing protector attenuation.

    Science.gov (United States)

    2010-10-01

    ... exposure to an 8-hour TWA of 90 decibels or lower, as required by § 227.115. (c) For employees who have...-weighted average of 85 decibels or lower. (d) The adequacy of hearing protector attenuation shall be re...

  18. Oral vaccination with attenuated Salmonella choleraesuis C500 ...

    African Journals Online (AJOL)

    user

    Oral vaccination with attenuated Salmonella choleraesuis C500 expressing recombinant UreB and. CagA antigens protects mice against Helicobacter pylori. J. G. Chen1, A. X. .... incubated for 1 h at 37°C. Serum IgG were detected by peroxidase- .... Molecular characterization of the 128-kDa immunodominant antigen.

  19. Adaptive disturbance attenuation via logic-based switching

    NARCIS (Netherlands)

    Battistelli, Giorgio; Mari, Daniele; Selvi, Daniela; Tesi, Alberto; Tesi, Pietro

    2014-01-01

    The problem of attenuating unknown and possibly time-varying disturbances acting on a linear time-invariant dynamical system is addressed by means of an adaptive switching control approach. Given a family of pre-designed stabilizing controllers, a supervisory unit infers in real-time the potential

  20. Measurement of acoustic attenuation in South Pole ice

    NARCIS (Netherlands)

    Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Adams, J.; Aguilar, J.A.; Ahlers, M.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S.W.; Bay, R.; Alba, J.L.B.; Beattie, K.; Beatty, J.J.; Bechet, S.; Becker, J.K.; Becker, K.H.; Benabderrahmane, M.L.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D.Z.; Bissok, M.; Blaufuss, E.; Boersma, D.J.; Bohm, C.; Boser, S.; Botner, O.; Bradley, L.; Braun, J.; Buitink, S.; Carson, M.; Chirkin, D.; Christy, B.; Clem, J.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D.F.; D'Agostino, M.V.; Danninger, M.; Clercq, C. De; Demirors, L.; Depaepe, O.; Descamps, F.; Desiati, P.; Vries-Uiterweerd, G. de; DeYoung, T.; Diaz-Velez, J.C.; Dreyer, J.; Dumm, J.P.; Duvoort, M.R.; Ehrlich, R.; Eisch, J.; Ellsworth, R.W.; Engdegard, O.; Euler, S.; Evenson, P.A.; Fadiran, O.; Fazely, A.R.; Feusels, T.; Filimonov, K.; Finley, C.; Foerster, M.M.; Fox, B.D.; Franckowiak, A.; Franke, R.; Gaisser, T.K.; Gallagher, J.; Ganugapati, R.; Geisler, M.; Gerhardt, L.; Gladstone, L.; Glusenkamp, T.; Goldschmidt, A.; Goodman, J.A.; Grant, D.; Griesel, T.; Gross, A.; Grullon, S.; Gunasingha, R.M.; Gurtner, M.; Gustafsson, L.; Ha, C.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Helbing, K.; Herquet, P.; Hickford, S.; Hill, G.C.; Hoffman, K.D.; Homeier, A.; Hoshina, K.; Hubert, D.; Huelsnitz, W.; Lafebre, S.J.

    2011-01-01

    Using the South Pole Acoustic Test Setup (SPATS) and a retrievable transmitter deployed in holes drilled for the IceCube experiment, we have measured the attenuation of acoustic signals by South Pole ice at depths between 190 m and 500 m. Three data sets, using different acoustic sources, have been

  1. Urgent challenges in implementing live attenuated influenza vaccine.

    Science.gov (United States)

    Singanayagam, Anika; Zambon, Maria; Lalvani, Ajit; Barclay, Wendy

    2017-08-02

    Conflicting reports have emerged about the effectiveness of the live attenuated influenza vaccine. The live attenuated influenza vaccine appears to protect particularly poorly against currently circulating H1N1 viruses that are derived from the 2009 pandemic H1N1 viruses. During the 2015-16 influenza season, when pandemic H1N1 was the predominant virus, studies from the USA reported a complete lack of effectiveness of the live vaccine in children. This finding led to a crucial decision in the USA to recommend that the live vaccine not be used in 2016-17 and to switch to the inactivated influenza vaccine. Other countries, including the UK, Canada, and Finland, however, have continued to recommend the use of the live vaccine. This policy divergence and uncertainty has far reaching implications for the entire global community, given the importance of the production capabilities of the live attenuated influenza vaccine for pandemic preparedness. In this Personal View, we discuss possible explanations for the observed reduced effectiveness of the live attenuated influenza vaccine and highlight the underpinning scientific questions. Further research to understand the reasons for these observations is essential to enable informed public health policy and commercial decisions about vaccine production and development in coming years. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. On the effectiveness of mangroves in attenuating cyclone induced waves

    NARCIS (Netherlands)

    Narayan, S.; Suzuki, T.; Stive, M.J.F.; Verhagen, H.J.; Ursem, W.N.J.; Ranasinghe, R.

    2010-01-01

    A study of the effectiveness of mangroves in attenuating cyclone- induced waves was done using the SWAN 40.81 numerical model. Hydraulic parameters during extreme events and local mangrove vegetation parameters were estimated for the Kanika Sands mangrove island near the upcoming Dhamra Port in

  3. Developement of a Light Attenuator Based on Glassy Reflections ...

    African Journals Online (AJOL)

    In the presented work, we have developed and designed a light attenuator based on the progressive decrease of the transmitted light intensity, when it undergoes multiple vitreous reflections across eight plates glasses arranged in a roof shape. Several tests were carried out using a laser light as a source. We have shown ...

  4. DEVELOPEMENT OF A LIGHT ATTENUATOR BASED ON GLASSY ...

    African Journals Online (AJOL)

    30 juin 2012 ... it undergoes multiple vitreous reflections across eight plates glasses arranged in a roof shape. Several tests were carried out using a laser light as a source. We have shown that the attenuation rate can be controlled by the choice of the incidence angle on the glasses slides, in addition we have confirmed, ...

  5. Vaccinations with live-attenuated Leishmania major promastigotes ...

    African Journals Online (AJOL)

    Background: Currently there is no vaccine available in use against any form of leishmaniases worldwide. Objective: To assess potential of a live-attenuated Leishmania major promastigates, for protection against a challenge infection with L. major in BALB/c mice. Design. A laboratory based study. Setting: Study was carried ...

  6. Comparative attenuation spectra of liquid skin-like phantoms

    CSIR Research Space (South Africa)

    Singh, A

    2010-09-01

    Full Text Available This study aims to extract and compare attenuation coefficients of different liquid skin-like phantoms representing Skin Types 1 to V1 with two methods, Spectrophotometric and Integrating Sphere methods. The correlation between the results of the 2...

  7. Study of gaseous attenuation at tropical locations | Adedugbu ...

    African Journals Online (AJOL)

    Oxygen and Water Vapour are the principal absorbers of transmitted radio signals in the troposphere. This paper evaluates the specific gaseous attenuation due to Oxygen and Water Vapour at four tropical sites in the frequency range of 10-350 GHz using Liebe model. The isolated resonant absorption line of Oxygen was ...

  8. Immunogenicity and safety of a live attenuated varicella vaccine in ...

    African Journals Online (AJOL)

    To investigate the safety of live attenuated varicella vaccine (aka strain) and the optimal virus titre/ dose required for immunogenicity in healthy South African children. ... Six subjects who were initially seropositive maintained or increased their titres post-vaccination; 3 of the 6 showed a booster response (a ;:;, 4-fold increase ...

  9. Attenuation of the haemodynamic response to placement of the ...

    African Journals Online (AJOL)

    Introduction: Application of the Mayfield clamp causes a significant haemodynamic response. Different methods have been used to attenuate this response. We compared two of these methods, namely alfentanil bolus (Group A) and nerve block of the scalp (Group B). METHOD: Twenty-two patients entered the study.

  10. Attenuation of salt-induced changes in photosynthesis by ...

    African Journals Online (AJOL)

    In parallel, NO application in salt-stressed plants attenuated the decrease in the photosynthetic parameters such as leaf chlorophyll, net photosynthetic rate (PN), stomatal conductance (gs), transpiration rate (E), the ratio of variable to maximum fluorescence (Fv/Fm), electron transport rate (ETR), the efficiency of excitation ...

  11. Measurement of mass attenuation coefficients in some Cr, Co and ...

    Indian Academy of Sciences (India)

    Home; Journals; Pramana – Journal of Physics; Volume 69; Issue 2. Measurement of mass attenuation coefficients in some Cr, Co and Fe compounds around the ... Author Affiliations. U Turgut1 O Şimşek1 E Büyükkasap1. Department of Physics Education, Education Faculty, Atatürk University, 25240, Erzurum, Turkey ...

  12. New technologies in using recombinant attenuated Salmonella vaccine vectors.

    Science.gov (United States)

    Curtiss, Roy; Xin, Wei; Li, Yuhua; Kong, Wei; Wanda, Soo-Young; Gunn, Bronwyn; Wang, Shifeng

    2010-01-01

    Recombinant attenuated Salmonella vaccines (RASVs) have been constructed to deliver antigens from other pathogens to induce immunity to those pathogens in vaccinated hosts. The attenuation means should ensure that the vaccine survives following vaccination to colonize lymphoid tissues without causing disease symptoms. This necessitates that attenuation and synthesis of recombinant gene encoded protective antigens do not diminish the ability of orally administered vaccines to survive stresses encountered in the gastrointestinal tract. We have eliminated these problems by using RASVs with regulated delayed expression of attenuation and regulated delayed synthesis of recombinant antigens. These changes result in RASVs that colonize effector lymphoid tissues efficiently to serve as "factories" to synthesize protective antigens that induce higher protective immune responses than achieved when using previously constructed RASVs. We have devised a biological containment system with regulated delayed lysis to preclude RASV persistence in vivo and survival if excreted. Attributes were added to reduce the mild diarrhea sometimes experienced with oral live RASVs and to ensure complete safety in newborns. These collective technologies have been used to develop a novel, low-cost, RASV-synthesizing, multiple-protective Streptococcus pneumoniae antigens that will be safe for newborns/infants and will induce protective immunity to diverse S. pneumoniae serotypes after oral immunization.

  13. Context discovery using attenuated Bloom codes: model description and validation

    NARCIS (Netherlands)

    Liu, F.; Heijenk, Geert

    A novel approach to performing context discovery in ad-hoc networks based on the use of attenuated Bloom filters is proposed in this report. In order to investigate the performance of this approach, a model has been developed. This document describes the model and its validation. The model has been

  14. Unusual Attenuation Recovery Process After Fiber Optic Cable Irradiation

    Science.gov (United States)

    Konečná, Z.; Plaček, V.; Havránek, P.

    2017-11-01

    At present, the number of optical cables in nuclear power plants has been increasing. Fiber optic cables are commonly used at nuclear power plants in instrumentation and control systems but they are usually used in environments without radiation. Nevertheless, currently, the number of applications in NPP containment with radiation is increasing. One of the most prevalent effects of radiation exposure is an increase of signal attenuation (signal loss). This is the result of fiber darkening due to radiation exposure and it is the main limitation factor in application of fiber optics in radiation environment. However, after the irradiation, the fiber optics go through a “recovery process” during which the optical properties improve again; i.e. attenuation decreases. However, we have found cable, where the expected healing process after few days changed its trend and the attenuation increased again to a value well above the attenuation just after the irradiation. This paper describes experiments that were carried out to explain this unusual recovery behaviour.

  15. ASSESSING AEROBIC NATURAL ATTENUATION OF TRICHLOROETHENE AT FOUR DOE SITES

    Energy Technology Data Exchange (ETDEWEB)

    Koelsch, Michael C.

    2005-03-03

    A 3-year Department of Energy Environmental Science Management Program (EMSP) project is currently investigating natural attenuation of trichloroethene (TCE) in aerobic groundwater. Determining whether TCE degradation occurs at meaningful rates under aerobic conditions via biological cometabolism has important implications for the assessment of natural attenuation. This presentation summarizes the results of a screening process to identify TCE plumes at DOE facilities that are suitable for assessing the rate of TCE attenuation under aerobic conditions. In order to estimate aerobic degradation rates, plumes had to meet the following criteria: TCE must be present in aerobic groundwater, a conservative co-contaminant must be present and have approximately the same source as TCE, and the groundwater velocity must be known. A total of 127 TCE plumes were considered across 24 DOE sites. The four sites retained for the assessment were: 1) Brookhaven National Laboratory, OU III; 2) Paducah Gaseous Diffusion Plant, Northwest Plume; 3) Rocky Flats Environmental Technology Site, Industrialized Area – Southwest Plume and 903 Pad South Plume; and 4) Savannah River Site, A/M Area Plume. The analysis indicates that TCE is being preferentially attenuated at environmentally significant rates under aerobic conditions with degradation half-lives ranging from 0.85 to 12 years in 8 of the 9 plumes evaluated.

  16. Wogonin Induces Eosinophil Apoptosis and Attenuates Allergic Airway Inflammation

    Science.gov (United States)

    Dorward, David A.; Sharma, Sidharth; Rennie, Jillian; Felton, Jennifer M.; Alessandri, Ana L.; Duffin, Rodger; Schwarze, Jurgen; Haslett, Christopher; Rossi, Adriano G.

    2015-01-01

    Rationale: Eosinophils are key effector cells in allergic diseases, including allergic rhinitis, eczema, and asthma. Their tissue presence is regulated by both recruitment and increased longevity at inflamed sites. Objectives: To investigate the ability of the flavone wogonin to induce eosinophil apoptosis in vitro and attenuate eosinophil-dominant allergic inflammation in vivo in mice. Methods: Human and mouse eosinophil apoptosis in response to wogonin was investigated by cellular morphology, flow cytometry, mitochondrial membrane permeability, and pharmacological caspase inhibition. Allergic lung inflammation was modeled in mice sensitized and challenged with ovalbumin. Bronchoalveolar lavage (BAL) and lung tissue were examined for inflammation, mucus production, and inflammatory mediator production. Airway hyperresponsiveness to aerosolized methacholine was measured. Measurements and Main Results: Wogonin induced time- and concentration-dependent human and mouse eosinophil apoptosis in vitro. Wogonin-induced eosinophil apoptosis occurred with activation of caspase-3 and was inhibited by pharmacological caspase inhibition. Wogonin administration attenuated allergic airway inflammation in vivo with reductions in BAL and interstitial eosinophil numbers, increased eosinophil apoptosis, reduced airway mucus production, and attenuated airway hyperresponsiveness. This wogonin-induced reduction in allergic airway inflammation was prevented by concurrent caspase inhibition in vivo. Conclusions: Wogonin induces eosinophil apoptosis and attenuates allergic airway inflammation, suggesting that it has therapeutic potential for the treatment of allergic inflammation in humans. PMID:25629436

  17. Comparison of test methods for hearing protector attenuation measurements

    DEFF Research Database (Denmark)

    Poulsen, Torben

    1998-01-01

    the same procedure is used in Europe, USA, Australia and New Zealand, but the methods differ in the way the sound field is established and in the way the test subjects are instructed before the tests. Presently the international standard ISO 4869-1 for hearing protector attenuation is under revision...

  18. Some physical and psychological aspects of noise attenuation by vegetation

    Science.gov (United States)

    Donald E. Aylor

    1977-01-01

    The physical mechanisms governing sound attenuation by foliage, stems, and ground are reviewed. Reflection of sound energy is found to be the primary mechanism. In addition, new experimental results are discussed that help to quantify the psychological effect of a plant barrier on perceived noise level. Listeners judged the loudness of noise transmitted through hemlock...

  19. Ixeris dentata (Thunb) Nakai attenuates cognitive impairment in ...

    African Journals Online (AJOL)

    Ixeris dentata (Thunb) Nakai attenuates cognitive impairment in MPTP-treated mouse model of Parkinson's disease. ... Therefore, IDE could potentially be developed as a therapeutic approach for the treatment of neurodegenerative diseases. Keywords: Ixeris dentata, Neurodegenerative disease, MPTP, Parkinson's ...

  20. Lg Attenuation Characteristic of Gujarat Region (Western India)

    Science.gov (United States)

    Jaiswal, Namrata; Singh, Chandrani

    2016-04-01

    We estimate the Lg attenuation characteristics of the Gujarat Region in Western India by using a reliable two-station method. This region comes under the V, IV and III seismicity zone. So, in India this is the seismic active region other than Himalayas, which shows high seismicity. Lg is typically the most prominent short-period seismic phase on high frequency seismogram observed over the continental paths from regional to teleseimic distance. We use data from 15 earthquakes with magnitude > 5 mb and focal depth Gujarat region. Low Q0 (Gujarat. The northern region of Saurashtra (Gujarat) shows a high Q0 (> 300) value. These observations are consistent with the results of the body wave attenuation structure reported for the region. The variations in the attenuation characteristics may be caused due to both the intrinsic and scattering contributions caused by thermal effects, sedimentary layer thickness as well as heterogeneities present below the study region. Our results are found to be comparable with the previous studies of the attenuation characteristics of the Gujarat region.

  1. Bicarbonate attenuates arterial desaturation during maximal exercise in humans

    DEFF Research Database (Denmark)

    Nielsen, Henning B; Bredmose, Per P; Strømstad, Morten

    2002-01-01

    in the difference between the end-tidal O2 pressure and arterial PO2 was similar in the two trials. Also, pulmonary O2 uptake and changes in muscle oxygenation as determined by near-infrared spectrophotometry during exercise were similar. The enlarged blood-buffering capacity after infusion of Bic attenuated...

  2. Outdoor FSO Communications Under Fog: Attenuation Modeling and Performance Evaluation

    KAUST Repository

    Esmail, Maged Abdullah

    2016-07-18

    Fog is considered to be a primary challenge for free space optics (FSO) systems. It may cause attenuation that is up to hundreds of decibels per kilometer. Hence, accurate modeling of fog attenuation will help telecommunication operators to engineer and appropriately manage their networks. In this paper, we examine fog measurement data coming from several locations in Europe and the United States and derive a unified channel attenuation model. Compared with existing attenuation models, our proposed model achieves a minimum of 9 dB, which is lower than the average root-mean-square error (RMSE). Moreover, we have investigated the statistical behavior of the channel and developed a probabilistic model under stochastic fog conditions. Furthermore, we studied the performance of the FSO system addressing various performance metrics, including signal-to-noise ratio (SNR), bit-error rate (BER), and channel capacity. Our results show that in communication environments with frequent fog, FSO is typically a short-range data transmission technology. Therefore, FSO will have its preferred market segment in future wireless fifth-generation/sixth-generation (5G/6G) networks having cell sizes that are lower than a 1-km diameter. Moreover, the results of our modeling and analysis can be applied in determining the switching/thresholding conditions in highly reliable hybrid FSO/radio-frequency (RF) networks.

  3. Asiatic acid attenuates malignancy of human metastatic ovarian ...

    African Journals Online (AJOL)

    Conclusion: Asiatic acid attenuates the malignancy of human metastatic ovarian cancer cells via epithelial-to-mesenchymal ... Keywords: Asiatic acid, Ovarian cancer, Metastasis, Epithelial-to-mesenchymal transition, Vometin. Tropical Journal of ... Ovarian cancer is a deadly disease accounting for 3 % of cancer while 5 ...

  4. Phase velocity and attenuation of plane waves in dissipative elastic ...

    African Journals Online (AJOL)

    An iteration method to find the roots of a complex transcendental equation is under scanner. This method identified as functional iteration method is being used mainly in wave propagation problems to calculate the phase velocity and the attenuation of plane harmonic waves in dissipative elastic plates. Few mathematical ...

  5. Immunogenicity and safety of a live attenuated varicella vaccine in ...

    African Journals Online (AJOL)

    Objectives. To investigate the safety of live attenuated varicella vaccine (aka strain) and the optimal virus titre/ dose required for immunogenicity in healthy South African children. Design. Double-blind randomised clinical study using two different lots of varicella vaccine, each at two different titres. Subjects were randomly ...

  6. Amplification and Attenuation across USArray using Ambient Noise Wavefront Tracking

    KAUST Repository

    Bowden, Daniel C.

    2017-11-15

    As seismic travel-time tomography continues to be refined using data from the vast USArray dataset, it is advantageous to also exploit the amplitude information carried by seismic waves. We use ambient noise cross correlation to make observations of surface-wave amplification and attenuation at shorter periods (8 – 32 seconds) than can be observed with only traditional teleseismic earthquake sources. We show that the wavefront tracking approach of [Lin et al., 2012a] can be successfully applied to ambient noise correlations, yielding results quite similar to those from earthquake observations at periods of overlap. This consistency indicates that the wavefront tracking approach is viable for use with ambient noise correlations, despite concerns of the inhomogeneous and unknown distribution of noise sources. The resulting amplification and attenuation maps correlate well with known tectonic and crustal structure; at the shortest periods, our amplification and attenuation maps correlate well with surface geology and known sedimentary basins, while our longest period amplitudes are controlled by crustal thickness and begin to probe upper mantle materials. These amplification and attenuation observations are sensitive to crustal materials in different ways than travel-time observations and may be used to better constrain temperature or density variations. We also value them as an independent means of describing the lateral variability of observed Rayleigh-wave amplitudes without the need for 3D tomographic inversions.

  7. Attenuation studies of booster-rocket propellants and their simulants

    Energy Technology Data Exchange (ETDEWEB)

    Weirick, L.J.

    1990-08-01

    A series of impact experiments on a composite propellant, an energetic propellant, and their simulants was recently completed using a light-gas gun. Previous experiments were done to obtain Hugoniot data, to investigate the pressure threshold at which a reaction occurs, and to measure spall damage at various impact velocities. The present studies measured the attenuation of shock waves in these materials, completing the shock characterization needed for material modeling. An initial impulse of 2.0 GPa magnitude and {approximately}0.6 {mu}s duration was imposed upon samples of various thicknesses. VISAR was used to measure the free-surface velocity at the back of the samples; these data were used to generate a curve of shock-wave attenuation versus sample thickness for each material. Results showed that all four materials attenuated the shock wave very similarly. Material thicknesses of 3.0, 7.62, 12.7, and 19.0 mm attenuated the shock wave {approximately}16%, 33%, 50%, and 66% respectively. 14 refs., 12 figs., 4 tabs.

  8. On the level-dependent attenuation of a perforated device.

    Science.gov (United States)

    Chen, Lan; Sang, Jinqiu; Li, Xiaodong

    2009-05-01

    To investigate the physical principle governing the level-dependent attenuation of a perforated earplug, a mathematical model is first established with the transfer-matrix method to calculate the noise reduction through a simplified device, one perforated panel with back cavity, mounted in an impedance tube. The model prediction is compared with the measured noise reduction through two series of large-scale devices and one device with the dimensions of the ear canal under continuous noise and sinusoidal excitations. The model helps to improve significantly the level-dependent attenuation of the large-scale device. It also illustrates that the attenuation is not solely determined by the resistance of the orifice, which has been a well accepted design concept, but resulted from an incorporated effect of the acoustic filter comprised of the acoustic impedance of the orifice and other elements in the earplug-ear-canal system. This mechanism can interpret a resonance at low incident levels on improper design and reveal approaches to eliminate it. Finally, the model's potential contributions to the design of a perforated earplug are discussed, along with the threshold of level-dependent attenuation supported with experimental evidence.

  9. Ixeris dentata (Thunb) Nakai Ethylacetate Extract Attenuates Sterol ...

    African Journals Online (AJOL)

    Ixeris dentata (Thunb) Nakai Ethylacetate Extract Attenuates Sterol Regulatory Element-Binding Proteins-1c via AMP-Activated Protein Kinase Activation. ... Methods: IDE extract was prepared by maceration in ethyl acetate. Its fractionation was carried out by column chromatography. HepG-2 cells were pretreated with ...

  10. Variable optical attenuator fabricated by direct UV writing

    DEFF Research Database (Denmark)

    Svalgaard, Mikael; Færch, Kjartan Ullitz; Andersen, L.U.

    2003-01-01

    It is demonstrated that direct ultraviolet writing of waveguides is a method suitable for mass production of compact variable optical attenuators with low insertion loss, low polarization-dependent loss, and high dynamic range. The fabrication setup is shown to be robust, providing good device...

  11. Measurement of mass attenuation coefficients in some Cr, Co and ...

    Indian Academy of Sciences (India)

    or the nonvalidity of the mixture rule. Mass attenuation and energy absorption coefficients are widely used in the study of interaction of γ-rays with matter. Many measurements have been reported [1–4]. In recent years, there has been renewed interest in the measurement of photon interaction cross-sections at low energies,.

  12. Optical Attenuation in MoNA and LISA Detector Elements

    Science.gov (United States)

    Rice, Logan; Wong, Jonathan; MoNA Collaboration

    2011-10-01

    The MoNA collaboration is a research group of students and faculty from 13 primarily undergraduate institutions, with detectors at the NSCL: MoNA (Modular Neutron Array) and the newly-built LISA (Large multi-Institutional Scintillating Array). These arrays each have 144 plastic scintillating bars. When a neutron collides with a hydrogen nucleus within the plastic, photomultiplier tubes at either end of the bar detect the scintillation photons. Their arrival times are used to determine the position of the event, but as the light travels through the detector it loses intensity exponentially. How dramatic this loss is can be described by a parameter called the attenuation length, with larger attenuation lengths corresponding to lower loss. Recently the MoNA collaboration conducted its LISA commissioning experiment investigating two-neutron decay states of 25O. As a part of LISA's commissioning, we measured the attenuation lengths of the individual detector bars that make up the LISA array and compared these lengths with those of the older MoNA array. We found that the LISA bars had a larger attenuation length on average with impacts on detector efficiency and effective threshold. The authors wish to acknowledge the contributions of the members of the MoNA Collaboration.

  13. Attenuation of polychlorinated biphenyl sorption to charcoal by humic acids

    NARCIS (Netherlands)

    Koelmans, A.A.; Meulman, B.; Meijer, T.; Jonker, M.T.O.

    2009-01-01

    Strong sorption to black carbon may limit the environmental risks of organic pollutants, but interactions with cosorbing humic acid (HA) may interfere. We studied the attenuative effect of HA additions on the sorption of polychlorinated biphenyls (PCBs) to a charcoal. "Intrinsic" sorption to

  14. Attenuation of polychlorinated biphenyl sorption to charcoal by humic acids.

    NARCIS (Netherlands)

    Koelmans, A.A.; Meulman, B.; Meijer, T.; Jonker, M.T.O.|info:eu-repo/dai/nl/175518793

    2009-01-01

    Strong sorption to black carbon may limit the environmental risks of organic pollutants, but interactions with cosorbing humic acid (HA) may interfere. We studied the attenuative effect of HA additions on the sorption of polychlorinated biphenyls (PCBs) to a charcoal. "Intrinsic" sorption to

  15. Attenuation correction in 4D-PET using a single-phase attenuation map and rigidity-adaptive deformable registration.

    Science.gov (United States)

    Kalantari, Faraz; Wang, Jing

    2017-02-01

    Four-dimensional positron emission tomography (4D-PET) imaging is a potential solution to the respiratory motion effect in the thoracic region. Computed tomography (CT)-based attenuation correction (AC) is an essential step toward quantitative imaging for PET. However, due to the temporal difference between 4D-PET and a single attenuation map from CT, typically available in routine clinical scanning, motion artifacts are observed in the attenuation-corrected PET images, leading to errors in tumor shape and uptake. We introduced a practical method to align single-phase CT with all other 4D-PET phases for AC. A penalized non-rigid Demons registration between individual 4D-PET frames without AC provides the motion vectors to be used for warping single-phase attenuation map. The non-rigid Demons registration was used to derive deformation vector fields (DVFs) between PET matched with the CT phase and other 4D-PET images. While attenuated PET images provide useful data for organ borders such as those of the lung and the liver, tumors cannot be distinguished from the background due to loss of contrast. To preserve the tumor shape in different phases, an ROI-covering tumor was excluded from nonrigid transformation. Instead the mean DVF of the central region of the tumor was assigned to all voxels in the ROI. This process mimics a rigid transformation of the tumor along with a nonrigid transformation of other organs. A 4D-XCAT phantom with spherical lung tumors, with diameters ranging from 10 to 40 mm, was used to evaluate the algorithm. The performance of the proposed hybrid method for attenuation map estimation was compared to (a) the Demons nonrigid registration only and (b) a single attenuation map based on quantitative parameters in individual PET frames. Motion-related artifacts were significantly reduced in the attenuation-corrected 4D-PET images. When a single attenuation map was used for all individual PET frames, the normalized root-mean-square error (NRMSE

  16. Acetaminophen attenuates lipid peroxidation in children undergoing cardiopulmonary bypass.

    Science.gov (United States)

    Simpson, Scott A; Zaccagni, Hayden; Bichell, David P; Christian, Karla G; Mettler, Bret A; Donahue, Brian S; Roberts, L Jackson; Pretorius, Mias

    2014-07-01

    Hemolysis, occurring during cardiopulmonary bypass, is associated with lipid peroxidation and postoperative acute kidney injury. Acetaminophen inhibits lipid peroxidation catalyzed by hemeproteins and in an animal model attenuated rhabdomyolysis-induced acute kidney injury. This pilot study tests the hypothesis that acetaminophen attenuates lipid peroxidation in children undergoing cardiopulmonary bypass. Single-center prospective randomized double-blinded study. University-affiliated pediatric hospital. Thirty children undergoing elective surgical correction of a congenital heart defect. Patients were randomized to acetaminophen (OFIRMEV [acetaminophen] injection; Cadence Pharmaceuticals, San Diego, CA) or placebo every 6 hours for four doses starting before the onset of cardiopulmonary bypass. Markers of hemolysis, lipid peroxidation (isofurans and F2-isoprostanes), and acute kidney injury were measured throughout the perioperative period. Cardiopulmonary bypass was associated with a significant increase in free hemoglobin (from a prebypass level of 9.8 ± 6.2 mg/dL to a peak of 201.5 ± 42.6 mg/dL postbypass). Plasma and urine isofuran and F2-isoprostane concentrations increased significantly during surgery. The magnitude of increase in plasma isofurans was greater than the magnitude in increase in plasma F2-isoprostanes. Acetaminophen attenuated the increase in plasma isofurans compared with placebo (p = 0.02 for effect of study drug). There was no significant effect of acetaminophen on plasma F2-isoprostanes or urinary makers of lipid peroxidation. Acetaminophen did not affect postoperative creatinine, urinary neutrophil gelatinase-associated lipocalin, or prevalence of acute kidney injury. Cardiopulmonary bypass in children is associated with hemolysis and lipid peroxidation. Acetaminophen attenuated the increase in plasma isofuran concentrations. Future studies are needed to establish whether other therapies that attenuate or prevent the effects of free

  17. IgG Glycan Hydrolysis Attenuates ANCA-Mediated Glomerulonephritis

    Science.gov (United States)

    van Timmeren, Mirjan M.; van der Veen, Betty S.; Stegeman, Coen A.; Petersen, Arjen H.; Hellmark, Thomas; Collin, Mattias

    2010-01-01

    Anti-neutrophil cytoplasmic autoantibodies (ANCA) directed against myeloperoxidase (MPO) and proteinase 3 (Pr3) are considered pathogenic in ANCA-associated necrotizing and crescentic glomerulonephritis (NCGN) and vasculitis. Modulation of ANCA IgG glycosylation may potentially reduce its pathogenicity by abolishing Fc receptor–mediated activation of leukocytes and complement. Here, we investigated whether IgG hydrolysis by the bacterial enzyme endoglycosidase S (EndoS) attenuates ANCA-mediated NCGN. In vitro, treatment of ANCA IgG with EndoS significantly attenuated ANCA-mediated neutrophil activation without affecting antigen-binding capacity. In a mouse model of anti-MPO IgG/LPS-induced NCGN, we induced disease with either unmodified or EndoS-treated (deglycosylated) anti-MPO IgG. In separate experiments, we administered EndoS systemically after disease induction with unmodified anti-MPO IgG. Pretreatment of anti-MPO IgG with EndoS reduced hematuria, leukocyturia, and albuminuria and attenuated both neutrophil influx and formation of glomerular crescents. After inducing disease with unmodified anti-MPO IgG, systemic treatment with EndoS reduced albuminuria and glomerular crescent formation when initiated after 3 but not 24 hours. In conclusion, IgG glycan hydrolysis by EndoS attenuates ANCA-induced neutrophil activation in vitro and prevents induction of anti-MPO IgG/LPS-mediated NCGN in vivo. Systemic treatment with EndoS early after disease induction attenuates the development of disease. Thus, modulation of IgG glycosylation is a promising strategy to interfere with ANCA-mediated inflammatory processes. PMID:20448018

  18. Preliminary seismic coda wave attenuation study of Pacaya volcano, Guatemala

    Science.gov (United States)

    Guettinger, Maximilian

    Pacaya volcano is a basaltic complex in the Central American Volcanic Arc in Guatemala. Pacaya has been in an open vent condition since 1961. During January 2015 we deployed 19 short period seismometer stations on Pacaya at distances less than 1.5 kilometers from the summit. The resulting data consisted of tremor and thousands of discrete events associated with ongoing outgassing. Where possible, individual events were identified and located. They were found to be high in the edifice near the vent. We used the decaying codas of these events to model the attenuation structure of the Pacaya edifice, following the energy density decay method of Aki and Chouet [1975]. We attempted to model the attenuation coda quality factor, Q c, at 482 events that were well recorded by the temporary network. After investigating a range of frequencies, we found a range of 2-10 Hz to be the best frequency range in terms of the frequency ranges analyzed. We found that there was not a significant dependence of Qc on P or S wave amplitude, so did not attempt to include a source term correction. Median Qc, selected using thresholds, ranged from as low as 146 at station PS12 to 194 at station PS06. In general, attenuation was lower at the western-most stations. We also interpreted that higher attenuation to the north and on the north summit may result from fracturing or magmatic sources and that the lower attenuation to the west may be related to the slide and subsidence that occurred.

  19. A heterogeneous nonlinear attenuating full-wave model of ultrasound.

    Science.gov (United States)

    Pinton, Gianmarco F; Dahl, Jeremy; Rosenzweig, Stephen; Trahey, Gregg E

    2009-03-01

    A full-wave equation that describes nonlinear propagation in a heterogeneous attenuating medium is solved numerically with finite differences in the time domain (FDTD). Three-dimensional solutions of the equation are verified with water tank measurements of a commercial diagnostic ultrasound transducer and are shown to be in excellent agreement in terms of the fundamental and harmonic acoustic fields and the power spectrum at the focus. The linear and nonlinear components of the algorithm are also verified independently. In the linear nonattenuating regime solutions match results from Field II, a well established software package used in transducer modeling, to within 0.3 dB. Nonlinear plane wave propagation is shown to closely match results from the Galerkin method up to 4 times the fundamental frequency. In addition to thermoviscous attenuation we present a numerical solution of the relaxation attenuation laws that allows modeling of arbitrary frequency dependent attenuation, such as that observed in tissue. A perfectly matched layer (PML) is implemented at the boundaries with a numerical implementation that allows the PML to be used with high-order discretizations. A -78 dB reduction in the reflected amplitude is demonstrated. The numerical algorithm is used to simulate a diagnostic ultrasound pulse propagating through a histologically measured representation of human abdominal wall with spatial variation in the speed of sound, attenuation, nonlinearity, and density. An ultrasound image is created in silico using the same physical and algorithmic process used in an ultrasound scanner: a series of pulses are transmitted through heterogeneous scattering tissue and the received echoes are used in a delay-and-sum beam-forming algorithm to generate a images. The resulting harmonic image exhibits characteristic improvement in lesion boundary definition and contrast when compared with the fundamental image. We demonstrate a mechanism of harmonic image quality

  20. Signal attenuation as a rat model of obsessive compulsive disorder.

    Science.gov (United States)

    Goltseker, Koral; Yankelevitch-Yahav, Roni; Albelda, Noa S; Joel, Daphna

    2015-01-09

    In the signal attenuation rat model of obsessive-compulsive disorder (OCD), lever-pressing for food is followed by the presentation of a compound stimulus which serves as a feedback cue. This feedback is later attenuated by repeated presentations of the stimulus without food (without the rat emitting the lever-press response). In the next stage, lever-pressing is assessed under extinction conditions (i.e., no food is delivered). At this stage rats display two types of lever-presses, those that are followed by an attempt to collect a reward, and those that are not. The latter are the measure of compulsive-like behavior in the model. A control procedure in which rats do not experience the attenuation of the feedback cue serves to distinguish between the effects of signal attenuation and of extinction. The signal attenuation model is a highly validated model of OCD and differentiates between compulsive-like behaviors and behaviors that are repetitive but not compulsive. In addition the measures collected during the procedure eliminate alternative explanations for differences between the groups being tested, and are quantitative, unbiased and unaffected by inter-experimenter variability. The major disadvantages of this model are the costly equipment, the fact that it requires some technical know-how and the fact that it is time-consuming compared to other models of OCD (11 days). The model may be used for detecting the anti- or pro-compulsive effects of pharmacological and non-pharmacological manipulations and for studying the neural substrate of compulsive behavior.

  1. Apparent Attenuation at High Frequencies in Southern California

    Science.gov (United States)

    Lin, Y. P.; Jordan, T. H.

    2016-12-01

    Accurately simulating strong motions for seismic hazard analysis requires accurate 3D models of crustal structure. At low frequencies (job of accounting 3D elastic scattering on wavefield amplitudes. At higher frequencies, however, anelastic attenuation becomes more important, and the elastic scattering depends on unresolved small-scale heterogeneities, giving rise to a complex apparent attenuation structure that depends on both position and frequency. We place constraints on this structure in the band 1-10 Hz through the analysis of earthquake waveforms recorded by the Southern California Seismic Network (SCSN). We localize signals in frequency and time using wavelet transforms, and we account for source structure and geometrical spreading by referencing the spectral amplitudes to values computed from synthetic seismograms. Inversions of large datasets recover an attenuation structure that, when averaged laterally and over frequency, is generally consistent with the tomographic study of Hauksson & Shearer (2006). In particular, we find that the apparent quality factor for P waves (QP) is less than the apparent quality factor for S waves (QS), in contradiction with the classical relation QP 2QS that has been used for most wavefield modeling at low frequencies. The data are consistent with QP anomalies being strongest in the low-Q, near-surface waveguide, suggesting that strong scattering from small-scale heterogeneities may play a role in explaining this discrepancy. The data also require that the apparent attenuation be strongly frequency dependent across the 1-10 Hz band. We use 3D tomographic inversions conditioned on the 3D velocity models to test the hypothesis that the lateral variations in apparent attenuation structure are strongly correlated with velocity variations.

  2. MRI-guided attenuation correction in whole-body PET/MR : assessment of the effect of bone attenuation

    NARCIS (Netherlands)

    Akbarzadeh, A.; Ay, M. R.; Ahmadian, A.; Alam, N. Riahi; Zaidi, H.

    Hybrid PET/MRI presents many advantages in comparison with its counterpart PET/CT in terms of improved soft-tissue contrast, decrease in radiation exposure, and truly simultaneous and multi-parametric imaging capabilities. However, the lack of well-established methodology for MR-based attenuation

  3. Modeled Radar Attenuation Rate Profile at the Vostok 5G Ice Core Site, Antarctica, Version 1

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set provides a modeled radar attenuation rate profile, showing the predicted contributions from pure ice and impurities to radar attenuation at the Vostok...

  4. Optimization of coronary optical coherence tomography imaging using the attenuation-compensated technique: a validation study.

    NARCIS (Netherlands)

    Teo, Jing Chun; Foin, Nicolas; Otsuka, Fumiyuki; Bulluck, Heerajnarain; Fam, Jiang Ming; Wong, Philip; Low, Fatt Hoe; Leo, Hwa Liang; Mari, Jean-Martial; Joner, Michael; Girard, Michael J A; Virmani, Renu; Bezerra, HG.; Costa, MA.; Guagliumi, G.; Rollins, AM.; Simon, D.; Gutiérrez-Chico, JL.; Alegría-Barrero, E.; Teijeiro-Mestre, R.; Chan, PH.; Tsujioka, H.; de Silva, R.; Otsuka, F.; Joner, M.; Prati, F.; Virmani, R.; Narula, J.; Members, WC.; Levine, GN.; Bates, ER.; Blankenship, JC.; Bailey, SR.; Bittl, JA.; Prati, F.; Guagliumi, G.; Mintz, G.S.; Costa, Marco; Regar, E.; Akasaka, T.; Roleder, T.; Jąkała, J.; Kałuża, GL.; Partyka, Ł.; Proniewska, K.; Pociask, E.; Girard, MJA.; Strouthidis, NG.; Ethier, CR.; Mari, JM.; Mari, JM.; Strouthidis, NG.; Park, SC.; Girard, MJA.; van der Lee, R.; Foin, N.; Otsuka, F.; Wong, P.K.; Mari, J-M.; Joner, M.; Nakano, M.; Vorpahl, M.; Otsuka, F.; Taniwaki, M.; Yazdani, SK.; Finn, AV.; Nakano, M.; Yahagi, K.; Yamamoto, H.; Taniwaki, M.; Otsuka, F.; Ladich, ER.; Girard, MJ.; Ang, M.; Chung, CW.; Farook, M.; Strouthidis, N.; Mehta, JS.; Foin, N.; Mari, JM.; Nijjer, S.; Sen, S.; Petraco, R.; Ghione, M.; Liu, X.; Kang, JU.; Virmani, R.; Kolodgie, F.D.; Burke, AP.; Farb, A.; Schwartz, S.M.; Yahagi, K.; Kolodgie, F.D.; Otsuka, F.; Finn, AV.; Davis, HR.; Joner, M.; Kume, T.; Akasaka, T.; Kawamoto, T.; Watanabe, N.; Toyota, E.; Neishi, Y.; Rieber, J.; Meissner, O.; Babaryka, G.; Reim, S.; Oswald, M.E.; Koenig, A.S.; Tearney, G. J.; Regar, E.; Akasaka, T.; Adriaenssens, T.; Barlis, P.; Bezerra, HG.; Yabushita, H.; Bouma, BE.; Houser, S. L.; Aretz, HT.; Jang, I-K.; Schlendorf, KH.; Guo, J.; Sun, L.; Chen, Y.D.; Tian, F.; Liu, HB.; Chen, L.; Kawasaki, M.; Bouma, BE.; Bressner, J. E.; Houser, S. L.; Nadkarni, S. K.; MacNeill, BD.; Jansen, CHP.; Onthank, DC.; Cuello, F.; Botnar, RM.; Wiethoff, AJ.; Warley, A.; von Birgelen, C.; Hartmann, A. M.; Kubo, T.; Akasaka, T.; Shite, J.; Suzuki, T.; Uemura, S.; Yu, B.; Habara, M.; Nasu, K.; Terashima, M.; Kaneda, H.; Yokota, D.; Ko, E.; Virmani, R.; Burke, AP.; Kolodgie, F.D.; Farb, A.; Takarada, S.; Imanishi, T.; Kubo, T.; Tanimoto, T.; Kitabata, H.; Nakamura, N.; Hattori, K.; Ozaki, Y.; Ismail, TF.; Okumura, M.; Naruse, H.; Kan, S.; Nishio, R.; Shinke, T.; Otake, H.; Nakagawa, M.; Nagoshi, R.; Inoue, T.; Sinclair, H.D.; Bourantas, C.; Bagnall, A.; Mintz, G.S.; Kunadian, V.; Tearney, G. J.; Yabushita, H.; Houser, S. L.; Aretz, HT.; Jang, I-K.; Schlendorf, KH.; van Soest, G.; Goderie, T.; Regar, E.; Koljenović, S.; Leenders, GL. van; Gonzalo, N.; Xu, C.; Schmitt, JM.; Carlier, SG.; Virmani, R.; van der Meer, FJ; Faber, D.J.; Sassoon, DMB.; Aalders, M.C.; Pasterkamp, G.; Leeuwen, TG. van; Schmitt, JM.; Knuttel, A.; Yadlowsky, M.; Eckhaus, MA.; Karamata, B.; Laubscher, M.; Leutenegger, M.; Bourquin, S.; Lasser, T.; Lambelet, P.; Vermeer, K.A.; Mo, J.; Weda, J.J.A.; Lemij, H.G.; Boer, JF. de

    2016-01-01

    PURPOSE To optimize conventional coronary optical coherence tomography (OCT) images using the attenuation-compensated technique to improve identification of plaques and the external elastic lamina (EEL) contour. METHOD The attenuation-compensated technique was optimized via manipulating contrast

  5. Guided wave attenuation in coated pipes buried in sand

    Science.gov (United States)

    Leinov, Eli; Cawley, Peter; Lowe, Michael J. S.

    2016-02-01

    Long-range guided wave testing (GWT) is routinely used for the monitoring and detection of corrosion defects in above ground pipelines in various industries. The GWT test range in buried, coated pipelines is greatly reduced compared to aboveground pipelines due to energy leakage into the embedding soil. In this study, we aim to increase test ranges for buried pipelines. The effect of pipe coatings on the T(0,1) and L(0,2) guided wave attenuation is investigated using a full-scale experimental apparatus and model predictions. Tests are performed on a fusion-bonded epoxy (FBE)-coated 8" pipe, buried in loose and compacted sand over a frequency range of 10-35 kHz. The application of a low impedance coating is shown to effectively decouple the influence of the sand on the ultrasound leakage from the buried pipe. We demonstrate ultrasonic isolation of a buried pipe by coating the pipe with a Polyethylene (PE)-foam layer that has a smaller impedance than both pipe and sand and the ability to withstand the overburden load from the sand. The measured attenuation in the buried PE-foam-FBE-coated pipe is substantially reduced, in the range of 0.3-1.2 dBm-1 for loose and compacted sand conditions, compared to buried FBE-coated pipe without the PE-foam, where the measured attenuation is in the range of 1.7-4.7 dBm-1. The acoustic properties of the PE-foam are measured independently using ultrasonic interferometry technique and used in model predictions of guided wave propagation in a buried coated pipe. Good agreement is found between the attenuation measurements and model predictions. The attenuation exhibits periodic peaks in the frequency domain corresponding to the through-thickness resonance frequencies of the coating layer. The large reduction in guided wave attenuation for PE-coated pipes would lead to greatly increased GWT test ranges, so such coatings would be attractive for new pipeline installations.

  6. Generation of pseudo-CT from a single MRI for PET/MR attenuation correction purposes

    Energy Technology Data Exchange (ETDEWEB)

    Monnier, Florian; Fayad, Hadi; Bert, Julian; Lapuyade-Lahorgue, Jerome; Hatt, Mathieu [INSERM UMR 1101, LaTIM, Brest (France); Veit-Haibach, Patrick; Delso, Gaspar [Nuclear Medicine Department, University Hospital Zurich (Switzerland); Visvikis, Dimitris [INSERM UMR 1101, LaTIM, Brest (France)

    2014-07-29

    Current MR attenuation correction (AC) approaches suffer from the lack of precision in the detection of bone and the assigned attenuation coefficients. In general, no unique transformation of MR image intensities into attenuation coefficients exists. The purpose of this work is to derive attenuation coefficient maps from a single MR sequence through the generation of a pseudo-CT map using a derived MRI intensity - CT Hounsfield Units (HU) relationship.

  7. Regional Attenuation Correction of Weather Radar Using a Distributed Microwave-Links Network

    OpenAIRE

    Yang Xue; Xi-chuan Liu; Tai-chang Gao; Chang-ye Yang; Kun Song

    2017-01-01

    The complex temporal-spatial variation of raindrop size distribution will affect the precision of precipitation quantitative estimates (QPE) produced from radar data, making it difficult to correct echo attenuation. Given the fact that microwave links can obtain the total path attenuation accurately, we introduce the concept of regional attenuation correction using a multiple-microwave-links network based on the tomographic reconstruction of attenuation coefficients. Derived from the radar-ba...

  8. A Neural network model for the separation of atmospheric effects on attenuation: Application to frequency scaling.

    OpenAIRE

    Barthès, Laurent; Mallet, Cécile; Brisseau, O.

    2006-01-01

    Attenuation due to the propagation of radio waves through the Earth's atmosphere plays a major role in satellite link attenuation at frequencies beyond 20 GHz. This paper presents the development of an artificial neural network (ANN) to separate out the respective roles played by the three types of contributor, namely, gases (oxygen and water vapor), clouds, and rain, to the overall attenuation of radio waves. Whereas the inputs to the ANN are the total attenuation measured at either one, two...

  9. Attenuation of monkeypox virus by deletion of genomic regions

    Science.gov (United States)

    Lopera, Juan G.; Falendysz, Elizabeth A.; Rocke, Tonie E.; Osorio, Jorge E.

    2015-01-01

    Monkeypox virus (MPXV) is an emerging pathogen from Africa that causes disease similar to smallpox. Two clades with different geographic distributions and virulence have been described. Here, we utilized bioinformatic tools to identify genomic regions in MPXV containing multiple virulence genes and explored their roles in pathogenicity; two selected regions were then deleted singularly or in combination. In vitro and in vivostudies indicated that these regions play a significant role in MPXV replication, tissue spread, and mortality in mice. Interestingly, while deletion of either region led to decreased virulence in mice, one region had no effect on in vitro replication. Deletion of both regions simultaneously also reduced cell culture replication and significantly increased the attenuation in vivo over either single deletion. Attenuated MPXV with genomic deletions present a safe and efficacious tool in the study of MPX pathogenesis and in the identification of genetic factors associated with virulence.

  10. A novel live-attenuated vaccine candidate for mayaro Fever.

    Directory of Open Access Journals (Sweden)

    William J Weise

    2014-08-01

    Full Text Available Mayaro virus (MAYV is an emerging, mosquito-borne alphavirus that causes a dengue-like illness in many regions of South America, and which has the potential to urbanize. Because no specific treatment or vaccine is available for MAYV infection, we capitalized on an IRES-based approach to develop a live-attenuated MAYV vaccine candidate. Testing in infant, immunocompetent as well as interferon receptor-deficient mice demonstrated a high degree of attenuation, strong induction of neutralizing antibodies, and efficacy against lethal challenge. This vaccine strain was also unable to infect mosquito cells, a major safety feature for a live vaccine derived from a mosquito-borne virus. Further preclinical development of this vaccine candidate is warranted to protect against this important emerging disease.

  11. Anatomy of the TAMA SAS seismic attenuation system

    CERN Document Server

    Marka, S; Ando, M; Bertolini, A; Cella, G; DeSalvo, R; Fukushima, M; Iida, Y; Jacquier, F; Kawamura, S; Nishi, Y; Numata, K; Sannibale, V; Somiya, K; Takahashi, R; Tariq, H; Tsubono, K; Ugas, J; Viboud, N; Wang Chen Yang; Yamamoto, H; Yoda, T

    2002-01-01

    The TAMA SAS seismic attenuation system was developed to provide the extremely high level of seismic isolation required by the next generation of interferometric gravitational wave detectors to achieve the desired sensitivity at low frequencies. Our aim was to provide good performance at frequencies above approx 10 Hz, while utilizing only passive subsystems in the sensitive frequency band of the TAMA interferometric gravitational wave detectors. The only active feedback is relegated below 6 Hz and it is used to damp the rigid body resonances of the attenuation chain. Simulations, based on subsystem performance characterizations, indicate that the system can achieve rms mirror residual motion measured in a few tens of nanometres. We will give a brief overview of the subsystems and point out some of the characterization results, supporting our claims of achieved performance. SAS is a passive, UHV compatible and low cost system. It is likely that extremely sensitive experiments in other fields will also profit ...

  12. Nutrient attenuation in rivers and streams, Puget Sound Basin, Washington

    Science.gov (United States)

    Sheibley, Rich W.; Konrad, Christopher P.; Black, Robert W.

    2015-01-01

    Nutrients such as nitrogen and phosphorus are important for aquatic ecosystem health. Excessive amounts of nutrients, however, can make aquatic ecosystems harmful for biota because enhanced growth and decay cycles of aquatic algae can reduce dissolved oxygen in the water. In Puget Sound marine waters, low dissolved oxygen concentrations are observed in a number of marine nearshore areas, and nutrients have been identified as a major stressor to the local ecosystem. Delivery of nutrients from major rivers in the Puget Sound Basin to the marine environment can be large. Therefore, it is important to identify factors related to how nutrients are retained (attenuated) within streams and rivers in the Puget Sound Basin. Physical, chemical, and biological factors related to nutrient attenuation were identified through a review of related scientific literature.

  13. Development of live attenuated influenza vaccines against pandemic influenza strains.

    Science.gov (United States)

    Coelingh, Kathleen L; Luke, Catherine J; Jin, Hong; Talaat, Kawsar R

    2014-07-01

    Avian and animal influenza viruses can sporadically transmit to humans, causing outbreaks of varying severity. In some cases, further human-to-human virus transmission does not occur, and the outbreak in humans is limited. In other cases, sustained human-to-human transmission occurs, resulting in worldwide influenza pandemics. Preparation for future pandemics is an important global public health goal. A key objective of preparedness is to gain an understanding of how to design, test, and manufacture effective vaccines that could be stockpiled for use in a pandemic. This review summarizes results of an ongoing collaboration to produce, characterize, and clinically test a library of live attenuated influenza vaccine strains (based on Ann Arbor attenuated Type A strain) containing protective antigens from influenza viruses considered to be of high pandemic potential.

  14. Anatomy of the TAMA SAS seismic attenuation system

    Energy Technology Data Exchange (ETDEWEB)

    Marka, Szabolcs [California Institute of Technology, MS 18-34, Pasadena, CA 91125 (United States); Takamori, Akiteru [Dept. of Physics, Univ. of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 1130033 (Japan); Ando, Masaki [Dept. of Physics, Univ. of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 1130033 (Japan); Bertolini, Alessandro [Universita di Pisa, Pisa (Italy); Cella, Giancarlo [Universita di Pisa, Pisa (Italy); DeSalvo, Riccardo [California Institute of Technology, MS 18-34, Pasadena, CA 91125 (United States); Fukushima, Mitsuhiro [National Astronomy Observatory of Japan, Mitaka, Tokyo 1818588 (Japan); Iida, Yukiyoshi [Dept. of Physics, Univ. of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 1130033 (Japan); Jacquier, Florian [INSA de Lyon, Lyon (France); Kawamura, Seiji [National Astronomy Observatory of Japan, Mitaka, Tokyo 1818588 (Japan); Nishi, Yuhiko [Dept. of Physics, Univ. of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 1130033 (Japan); Numata, Kenji [Dept. of Physics, Univ. of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 1130033 (Japan); Sannibale, Virginio [California Institute of Technology, MS 18-34, Pasadena, CA 91125 (United States); Somiya, Kentaro [Dept. of Advanced Materials Science, Univ. of Tokyo, Bunkyo-ku, Tokyo 1130033 (Japan); Takahashi, Ryutaro [National Astronomy Observatory of Japan, Mitaka, Tokyo 1818588 (Japan); Tariq, Hareem [California Institute of Technology, MS 18-34, Pasadena, CA 91125 (United States); Tsubono, Kimio [Dept. of Physics, Univ. of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 1130033 (Japan); Ugas, Jose [California Institute of Technology, MS 18-34, Pasadena, CA 91125 (United States); Viboud, Nicolas [INSA de Lyon, Lyon (France); Wang Chenyang [California Institute of Technology, MS 18-34, Pasadena, CA 91125 (United States); Yamamoto, Hiroaki [California Institute of Technology, MS 18-34, Pasadena, CA 91125 (United States); Yoda, Tatsuo [Dept. of Physics, Univ. of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 1130033 (Japan)

    2002-04-07

    The TAMA SAS seismic attenuation system was developed to provide the extremely high level of seismic isolation required by the next generation of interferometric gravitational wave detectors to achieve the desired sensitivity at low frequencies. Our aim was to provide good performance at frequencies above {approx}10 Hz, while utilizing only passive subsystems in the sensitive frequency band of the TAMA interferometric gravitational wave detectors. The only active feedback is relegated below 6 Hz and it is used to damp the rigid body resonances of the attenuation chain. Simulations, based on subsystem performance characterizations, indicate that the system can achieve rms mirror residual motion measured in a few tens of nanometres. We will give a brief overview of the subsystems and point out some of the characterization results, supporting our claims of achieved performance. SAS is a passive, UHV compatible and low cost system. It is likely that extremely sensitive experiments in other fields will also profit from our study.

  15. Astaxanthin interacts with selenite and attenuates selenite-induced cataractogenesis.

    Science.gov (United States)

    Liao, Jiahn-Haur; Chen, Chien-Sheng; Maher, Timothy J; Liu, Chiung-Yueh; Lin, Mei-Hsiang; Wu, Tzu-Hua; Wu, Shih-Hsiung

    2009-03-16

    Selenite, the most commonly encountered toxic form of selenium, in overdose, is used to induce cataracts in rats. This study demonstrated that selenite, but not selenate, would interact with the carotenoid astaxanthin (ASTX), as determined using isothermal titration calorimetry and NMR. The maximum absorption of ASTX decreased with increasing selenite concentration, indicating that the conjugated system of ASTX was changed by selenite. Such interactions between ASTX and selenite were also supported by the attenuation of selenite-induced turbidity by ASTX (0-12.5 microM) in vitro. In vivo experiments also showed that ASTX attenuated selenite-induced cataractogenesis in rats. In summary, this is the first report of a direct interaction of ASTX with selenite. This interaction is supported by an in vitro assay and may be partially responsible for the ASTX observed in vivo protection against selenite-induced cataractogenesis.

  16. Assessing aerobic natural attenuation of trichloroethene at four DOE sites

    Energy Technology Data Exchange (ETDEWEB)

    Koelsch, Michael C. [North Wind, Inc., Idaho Falls, ID (United States); Starr, Robert C. [North Wind, Inc., Idaho Falls, ID (United States); Sorenson, Jr., Kent S. [CDM, Inc., Denver, CO (United States)

    2005-03-01

    A 3-year Department of Energy Environmental Science Management Program (EMSP) project is currently investigating natural attenuation of trichloroethane (TCE) in aerobic groundwater. This presentation summarizes the results of a screening process to identify TCE plumes at DOE facilities that are suitable for assessing the rate of TCE cometabolism under aerobic conditions. In order to estimate aerobic degradation rates, plumes had to meet the following criteria: TCE must be present in aerobic groundwater, a conservative co-contaminant must be present and have approximately the same source as TCE, and the groundwater velocity must be known. A total of 127 TCE plumes were considered across 24 DOE sites. The four sites retained for the assessment were: (1) Brookhaven National Laboratory, OU III; (2) Paducah Gaseous Diffusion Plant, Northwest Plume; (3) Rocky Flats Environmental Technology Site, Industrialized Area--Southwest Plume and 903 Pad South Plume; and (4) Savannah River Site, A/M Area Plume. For each of these sites, a co-contaminant derived from the same source area as TCE was used as a nonbiodegrading tracer. The tracer determined the extent to which concentration decreases in the plume can be accounted for solely by abiotic processes such as dispersion and dilution. Any concentration decreases not accounted for by these processes must be explained by some other natural attenuation mechanism. Thus, ''half-lives'' presented herein are in addition to attenuation that occurs due to hydrologic mechanisms. This ''tracer-corrected method'' has previously been used at the DOE's Idaho National Engineering and Environmental Laboratory in conjunction with other techniques to document the occurrence of intrinsic aerobic cometabolism. Application of this method to other DOE sites is the first step to determining whether this might be a significant natural attenuation mechanism on a broader scale. Application of the tracer

  17. The UV attenuation in JWST target VV 191

    Science.gov (United States)

    Holwerda, Benne

    2017-08-01

    We aim to map the UV-near-IR attenuation curve along many sightlines within nearby disk galaxies to resolve a large fundamental uncertainty in galaxy evolution studies: the variance in the attenuation curve within an indivual galaxy disk on linear scales beautifully backlights the outer disk of a foreground face-on spiral galaxy.Dither strategy:We opt for a 2-point dither in the case of the F336W observations (1 orbit) and a 3pt dither strategy for the F225W observations. The 9 orbits for the F225W observations are broken into three groupings of 3 orbits in the 3 dither pattern. This is to ensure correction of cosmics and detector artifacts. Our secondary aim is an HST/JWST image with good public outreach potential and our aim is to maximize image quality for this reason as well.

  18. Chondroitin sulfate attenuates formalin-induced persistent tactile allodynia

    Directory of Open Access Journals (Sweden)

    Wataru Nemoto

    2016-08-01

    Full Text Available We examined the effect of chondroitin sulfate (CS, a compound used in the treatment of osteoarthritis and joint pain, on the formalin-induced tactile allodynia in mice. A repeated oral administration of CS (300 mg/kg, b.i.d. significantly ameliorated the formalin-induced tactile allodynia from day 10 after formalin injection. On day 14, the phosphorylation of spinal p38 MAPK and subsequent increase in c-Fos-immunoreactive dorsal lumbar neurons were attenuated by the repeated administration of CS. These findings suggest that CS attenuates formalin-induced tactile allodynia through the inhibition of p38 MAPK phosphorylation and subsequent up-regulation of c-Fos expression in the dorsal lumbar spinal cord.

  19. Material identification based upon energy-dependent attenuation of neutrons

    Science.gov (United States)

    Marleau, Peter

    2015-10-06

    Various technologies pertaining to identifying a material in a sample and imaging the sample are described herein. The material is identified by computing energy-dependent attenuation of neutrons that is caused by presence of the sample in travel paths of the neutrons. A mono-energetic neutron generator emits the neutron, which is downscattered in energy by a first detector unit. The neutron exits the first detector unit and is detected by a second detector unit subsequent to passing through the sample. Energy-dependent attenuation of neutrons passing through the sample is computed based upon a computed energy of the neutron, wherein such energy can be computed based upon 1) known positions of the neutron generator, the first detector unit, and the second detector unit; or 2) computed time of flight of neutrons between the first detector unit and the second detector unit.

  20. Modelling of Attenuation and Crosstalk of Cascaded Transmission Lines

    Directory of Open Access Journals (Sweden)

    Pavel Lafata

    2011-01-01

    Full Text Available This paper deals with the measurements and modelling of attenuation and near-end (NEXT and far-end (FEXT crosstalk for cascaded metallic transmission lines. The transmission parameters of homogenous metallic line can be easily described by telegraph equations or cascade matrix; there are also several models for NEXT and FEXT frequency dependence. But these models and equations could not be applied in the situation of two or more different cascaded transmission lines, because these cascaded lines do not meet the essential condition of overall homogenous transmission line. However in such case, it is still possible to estimate the overall transmission characteristics of the whole combination thanks to the characteristics of each separate element. This paper brings the description of complex measurements performed for the combination of three different metallic cables and based on these measurements, several conclusions about the possibilities of modelling the attenuation and NEXT and FEXT crosstalk for cascaded transmission lines are presented.

  1. Estimating risk for earth-satellite attenuation prediction

    Science.gov (United States)

    Crane, Robert K.

    1993-01-01

    Annual cumulative distributions of attenuation measurements and of rain-rate measurements were obtained from several locations in Europe and the United States. They were analyzed to estimate the year-to-year variability to be associated with a prediction of the expected cumulative distribution. Two models were constructed to estimate variability, an ad hoc model that summarized a number of observations when compared to model predictions and a probabilistic model that applied the ideas of order statistics to the prediction problem when the number of independent attenuation or rain-rate events in a sample year could be estimated. Based on these models, the statistical uncertainty in a model prediction may be estimated. The estimation procedure also provides an answer to the question of the number of years of observation needed to provide an estimate of the empirical distribution with a specified statistical uncertainty.

  2. The Attenuation of Torsional Strain Wave in a PMMA Rod

    OpenAIRE

    田辺, 裕治; 前川, 一郎; 半田, 晋一; 原, 利昭; Tanabe, Yuji; Maekawa, Ichiro; Handa, Shinichi; Hara, Toshiaki

    1990-01-01

    In order to clarify the strain attenuation during shear wave propagation, impact torsion experiments are carried out using a PMMA rod specimen. The strain pulses measured by strain gages are complicated due to the superposition of many reflected and transmitted waves from the supported end of the specimen. To obtain data from such pulses for determining a viscoelastic model, a method which modifies the pulse form is developed taking into account wave propagation behavior in the experimental s...

  3. Working memory load attenuates emotional enhancement in recognition memory

    OpenAIRE

    Miendlarzewska, Ewa A.; van Elswijk, Gijs; Cannistraci, Carlo V.; van Ee, Raymond

    2013-01-01

    Emotionally arousing stimuli are perceived and remembered better than neutral stimuli. Under threat, this negativity bias is further increased. We investigated whether working memory (WM) load can attenuate incidental memory for emotional images. Two groups of participants performed the N-back task with two WM load levels. In one group, we induced anxiety using a threat of shock paradigm to increase attentional processing of negative information. During task performance we incidentally and br...

  4. Working memory load attenuates emotional enhancement in recognition memory

    OpenAIRE

    Ewa Aurelia Miendlarzewska; Gijs eVan Elswijk; Carlo Vittorio Cannistraci; Raymond evan Ee

    2013-01-01

    Emotionally arousing stimuli are perceived and remembered better than neutral stimuli. Under threat, this negativity bias is further increased. We investigated whether working memory load can attenuate incidental memory for emotional images. Two groups of participants performed the N-back task with two working memory load levels. In one group, we induced anxiety using a threat-of-shock paradigm to increase attentional processing of negative information. During task performance we incidentally...

  5. Serotonin and vasoactive intestinal peptide antagonists attenuate rotavirus diarrhoea

    OpenAIRE

    Kordasti, S; Sjövall, H; Lundgren, O; Svensson, L

    2004-01-01

    Background and aims: The mechanisms underlying intestinal secretion in rotavirus diarrhoea remain to be established. We previously reported that rotavirus evokes intestinal fluid and electrolyte secretion by activation of the enteric nervous system. We now report that antagonists for the 5-hydroxytryptamine 3 receptor (5-HT3) and vasoactive intestinal peptide (VIP) receptor, but not antagonists for 5-hydroxytryptamine 4 receptor or the muscarinic receptor, attenuate rotavirus induced diarrhoea.

  6. Stochastic solution to a time-fractional attenuated wave equation.

    Science.gov (United States)

    Meerschaert, Mark M; Straka, Peter; Zhou, Yuzhen; McGough, Robert J

    2012-10-01

    The power law wave equation uses two different fractional derivative terms to model wave propagation with power law attenuation. This equation averages complex nonlinear dynamics into a convenient, tractable form with an explicit analytical solution. This paper develops a random walk model to explain the appearance and meaning of the fractional derivative terms in that equation, and discusses an application to medical ultrasound. In the process, a new strictly causal solution to this fractional wave equation is developed.

  7. Attenuation studies near K-absorption edges using Compton ...

    Indian Academy of Sciences (India)

    Abstract. We have carried out photon attenuation measurements at several energies in the range from 49.38 keV to 57.96 keV around the K-absorption edges of the rare earth elements Sm, Eu, Gd, Tb, Dy and Er using 59.54 keV gamma rays from 241Am source after Compton scattering from an aluminium target. Pellets of ...

  8. Acetazolamide Attenuates Lithium-Induced Nephrogenic Diabetes Insipidus.

    Science.gov (United States)

    de Groot, Theun; Sinke, Anne P; Kortenoeven, Marleen L A; Alsady, Mohammad; Baumgarten, Ruben; Devuyst, Olivier; Loffing, Johannes; Wetzels, Jack F; Deen, Peter M T

    2016-07-01

    To reduce lithium-induced nephrogenic diabetes insipidus (lithium-NDI), patients with bipolar disorder are treated with thiazide and amiloride, which are thought to induce antidiuresis by a compensatory increase in prourine uptake in proximal tubules. However, thiazides induced antidiuresis and alkalinized the urine in lithium-NDI mice lacking the sodium-chloride cotransporter, suggesting that inhibition of carbonic anhydrases (CAs) confers the beneficial thiazide effect. Therefore, we tested the effect of the CA-specific blocker acetazolamide in lithium-NDI. In collecting duct (mpkCCD) cells, acetazolamide reduced the cellular lithium content and attenuated lithium-induced downregulation of aquaporin-2 through a mechanism different from that of amiloride. Treatment of lithium-NDI mice with acetazolamide or thiazide/amiloride induced similar antidiuresis and increased urine osmolality and aquaporin-2 abundance. Thiazide/amiloride-treated mice showed hyponatremia, hyperkalemia, hypercalcemia, metabolic acidosis, and increased serum lithium concentrations, adverse effects previously observed in patients but not in acetazolamide-treated mice in this study. Furthermore, acetazolamide treatment reduced inulin clearance and cortical expression of sodium/hydrogen exchanger 3 and attenuated the increased expression of urinary PGE2 observed in lithium-NDI mice. These results show that the antidiuresis with acetazolamide was partially caused by a tubular-glomerular feedback response and reduced GFR. The tubular-glomerular feedback response and/or direct effect on collecting duct principal or intercalated cells may underlie the reduced urinary PGE2 levels with acetazolamide, thereby contributing to the attenuation of lithium-NDI. In conclusion, CA activity contributes to lithium-NDI development, and acetazolamide attenuates lithium-NDI development in mice similar to thiazide/amiloride but with fewer adverse effects. Copyright © 2016 by the American Society of Nephrology.

  9. Molinate biodegradation in soils: natural attenuation versus bioaugmentation.

    Science.gov (United States)

    Lopes, Ana R; Danko, Anthony S; Manaia, Célia M; Nunes, Olga C

    2013-03-01

    The aims of the present study were to assess the potential of natural attenuation or bioaugmentation to reduce soil molinate contamination in paddy field soils and the impact of these bioremediation strategies on the composition of soil indigenous microbiota. A molinate mineralizing culture (mixed culture DC) was used as inoculum in the bioaugmentation assays. Significantly higher removal of molinate was observed in bioaugmentation than in natural attenuation microcosms (63 and 39 %, respectively) after 42 days of incubation at 22 °C. In the bioaugmentation assays, the impact of Gulosibacter molinativorax ON4(T) on molinate depletion was observed since the gene encoding the enzyme responsible for the initial molinate breakdown (harboured by that actinobacterium) was only detected in inoculated microcosms. Nevertheless, the exogenous mixed culture DC did not overgrow as the heterotrophic counts of the bioaugmentation microcosms were not significantly different from those of natural attenuation and controls. Moreover, the actinobacterial clone libraries generated from the bioaugmentation microcosms did not include any 16S rRNA gene sequences with significant similarity to that of G. molinativorax ON4(T). The multivariate analysis of the 16S rRNA DGGE patterns of the soil microcosm suggested that the activity of mixed culture DC did not affect the soil bacterial community structure since the DGGE patterns of the bioaugmentation microcosms clustered with those of natural attenuation and controls. Although both bioremediation approaches removed molinate without indigenous microbiota perturbation, the results suggested that bioaugmentation with mixed culture DC was more effective to treat soils contaminated with molinate.

  10. Advanced reconstruction of attenuation maps using SPECT emission data only

    Science.gov (United States)

    Salomon, André; Goedicke, Andreas; Aach, Til

    2009-02-01

    Today, attenuation corrected SPECT, typically performed using CT or Gadolinium line source based transmission scans, is more and more becoming standard in many medical applications. Moreover, the information about the material density distribution provided by these scans is key for other artifact compensation approaches in advanced SPECT reconstruction. Major drawbacks of these approaches are the additional patient radiation and hardware/maintenance costs as well as the additional workflow effort, e.g. if the CT scans are not performed on a hybrid scanner. It has been investigated in the past, whether it is possible to recover this structural information solely from the SPECT scan data. However, the investigated methods often result in noticeable image artifacts due to cross-dependences between attenuation and activity distribution estimation. With the simultaneous reconstruction method presented in this paper, we aim to effectively prevent these typical cross-talk artifacts using a-priori known atlas information of a human body. At first, an initial 3D shape model is coarsely registered to the SPECT data using anatomical landmarks and each organ structure within the model is identified with its typical attenuation coefficient. During the iterative reconstruction based on a modified ML-EM scheme, the algorithm simultaneously adapts both, the local activity estimation and the 3D shape model in order to improve the overall consistency between measured and estimated sinogram data. By explicitly avoiding topology modifications resulting in a non-anatomical state, we ensure that the estimated attenuation map remains realistic. Several tests with simulated as well as real patient SPECT data were performed to test the proposed algorithm, which demonstrated reliable convergence behaviour in both cases. Comparing the achieved results with available reference data, an overall good agreement for both cold as well as hot activity regions could be observed (mean deviation: -5.98%).

  11. Attenuation of high-energy x rays by iron shielding

    Energy Technology Data Exchange (ETDEWEB)

    Bespalov, V.I.; Chakhlov, V.L.; Shtein, M.M.

    1988-04-01

    Monte Carlo calculations are presented on electron-accelerator x-ray spectra for actual target thicknesses and electron energies of 4-50 MeV. Effective attenuation coefficients have been obtained as well as build-up factors for collimated beams andiron shielding of thickness form 1 to 80 cm. The radiation contrast has been determined as a function of thickness for this energy range.

  12. Attenuation of sepsis-induced rat liver injury by epigallocatechin ...

    African Journals Online (AJOL)

    http://dx.doi.org/10.4314/tjpr.v16i12.11. Original Research Article. Attenuation of sepsis-induced rat liver injury by epigallocatechin gallate via suppression of oxidative stress-related inflammation. Jian-xin Yang1, Yu-lin Li1*, Ning-chuan Shi2. 1Department of Emergency, The Second Affiliated Hospital, College of Medicine, ...

  13. Seismic Attenuation System (sas) in the KAMIOKA Mine

    Science.gov (United States)

    Takahashi, Ryutaro; Desalvo, Riccardo; Yamamoto, Kazuhiro; Uchiyama, Takashi; Sekiguchi, Takanori; Ishizaki, Hideharu; Takamori, Akiteru; Majorana, Ettore; van den Brand, Jo; Hennes, Eric; Bertolini, Alessandro

    2015-01-01

    The second/third generation interferometric gravitational wave detectors need not only strong attenuation at the observation band but also reduction of root mean square motion of the mirrors. Many kinds of mechanisms for isolation at low frequencies have been suggested for gravitational wave detectors. An inverted pendulum and geometric anti-spring filters are used in the isolator for KAGRA located in the Kamioka mine. We employed two layer tunnels to put the isolators onto the ground rock directly.

  14. Radiation attenuation and opacity in smoke and water sprays

    Science.gov (United States)

    Parent, Gilles; Boulet, Pascal; Morlon, Romain; Blanchard, Elizabeth

    2017-08-01

    Radiation attenuation through sprays, smoke and mixings of both media was studied in the infrared and in the visible range, by conducting real scale experiments in a corridor. The effect of water injection by a water mist nozzle and a sprinkler device was investigated. Radiation attenuation in the infrared range and opacity in the visible range were measured, by using a FTIR spectrometer and a dedicated opacimetry device especially designed for the present application. Experiments were done using either a blackbody source for attenuation characterization, or a heptane pool fire aimed at producing smoke for opacity measurements. For tests with smoke, the difficulties raised by the harsh environment involving a hot mixing of gas plus soot and vapor carrying water droplets were circumvented with an original device involving an optical fiber network. Mean infrared transmission was found equal to 12% for the water mist (with a 25 L/min water flowrate) and 37% for the sprinkler (with a 91 L/min water flowrate). Fitting the infrared transmission spectra with results obtained using a Monte Carlo simulation provided an estimation of the water volumetric fraction in the spray. It was shown that the better attenuation capability of the water mist is due to two factors: (1) a higher extinction coefficient of the water mist for a given water volumetric fraction due to the small size of the injected droplets and (2) a higher water volumetric fraction. Opacity measurements in the visible range yielded a measured extinction coefficient in good agreement with an estimation obtained with the Mie theory and the identified water volumetric fraction. Moreover, the water sprays (sprinkler or water mist) was seen to lead to a quick de-stratification of the smoke layer. When the spraying operation was stopped, the visibility re-increased in two main steps: a first step of fast increase and a second step of slow increase needing a few tens of seconds to get again a fully stratified smoke

  15. The Seismic Attenuation Structure of the East Pacific Rise

    Science.gov (United States)

    1992-02-27

    Clawson, S. R., R. B. Smith, and H. M. Benz, P wave attenuation of the Yellowstone caldera from three-dimensional inversion of spectral decay using...measurements obtained at high temperatures are presented by Jackson et al. [19921 for a dunite sample from the same formation as that used by Berckhemer et al...manifested by small offsets of the axial summit caldera and changes in orientation of the rise axis [e.g., Macdonald et al., 1992]. To the extent that

  16. A disorder-based strategy for tunable, broadband wave attenuation

    Science.gov (United States)

    Zhang, Weiting; Celli, Paolo; Cardella, Davide; Gonella, Stefano

    2017-04-01

    One of the most daunting limitations of phononic crystals and acoustic/elastic metamaterials is their passivity: a given configuration is bound to display its phononic properties only around its design point, i.e., working at some pre-determined operating conditions. In the past decade, this shortcoming has inspired the design of phononic media with tunable wave characteristics; noteworthy results have been obtained through a family of methodologies involving shunted piezoelectric elements. Shunting a piezoelectric element means connecting it to a passive electric circuit; tunability stems from the ability to modify the effective mechanical properties of the piezoelectric medium by modifying the circuit characteristics. One of the most popular shunting circuits is the resistor-inductor, which allows the patch-and-shunt system to behave as an electromechanical resonator. A common motif among the works employing shunted piezos for phononic control is periodicity: the patches are typically periodically placed in the domain and the circuits are identically tuned. The objective of this work is to demonstrate that the wave attenuation performance of structures with shunted piezoelectric patches can be improved by leveraging notions of organized disorder. Based on the idea of rainbow trapping broadband wave attenuation obtained by tuning an array of resonators at distinct neighboring frequencies we design and test an electromechanical waveguide structure capable of attenuating waves over broad frequency ranges. In order to emphasize the fact that periodicity is not a binding requirement when working with RL shunts (which induce locally resonant bandgaps), we report on the performance of random arrangements of patches. In an attempt to demonstrate the tunability attribute of our strategy, we take advantage of the reconfigurability of the circuits to show how a single waveguide can attenuate both waves and vibrations over different frequency ranges.

  17. Mesenchymal Dental Pulp Cells Attenuate Dentin Resorption in Homeostasis

    Science.gov (United States)

    Zheng, Y.; Chen, M.; He, L.; Marão, H.F.; Sun, D.M.; Zhou, J.; Kim, S.G.; Song, S.; Wang, S.L.

    2015-01-01

    Dentin in permanent teeth rarely undergoes resorption in development, homeostasis, or aging, in contrast to bone that undergoes periodic resorption/remodeling. The authors hypothesized that cells in the mesenchymal compartment of dental pulp attenuate osteoclastogenesis. Mononucleated and adherent cells from donor-matched rat dental pulp (dental pulp cells [DPCs]) and alveolar bone (alveolar bone cells [ABCs]) were isolated and separately cocultured with primary rat splenocytes. Primary splenocytes readily aggregated and formed osteoclast-like cells in chemically defined osteoclastogenesis medium with 20 ng/mL of macrophage colony-stimulating factor (M-CSF) and 50 ng/mL of receptor activator of nuclear factor κB ligand (RANKL). Strikingly, DPCs attenuated osteoclastogenesis when cocultured with primary splenocytes, whereas ABCs slightly but significantly promoted osteoclastogenesis. DPCs yielded ~20-fold lower RANKL expression but >2-fold higher osteoprotegerin (OPG) expression than donor-matched ABCs, yielding a RANKL/OPG ratio of 41:1 (ABCs:DPCs). Vitamin D3 significantly promoted RANKL expression in ABCs and OPG in DPCs. In vivo, rat maxillary incisors were atraumatically extracted (without any tooth fractures), followed by retrograde pulpectomy to remove DPCs and immediate replantation into the extraction sockets to allow repopulation of the surgically treated root canal with periodontal and alveolar bone–derived cells. After 8 wk, multiple dentin/root resorption lacunae were present in root dentin with robust RANKL and OPG expression. There were areas of dentin resoprtion alternating with areas of osteodentin formation in root dentin surface in the observed 8 wk. These findings suggest that DPCs of the mesenchymal compartment have an innate ability to attenuate osteoclastogenesis and that this innate ability may be responsible for the absence of dentin resorption in homeostasis. Mesenchymal attenuation of dentin resorption may have implications in internal

  18. Mesenchymal dental pulp cells attenuate dentin resorption in homeostasis.

    Science.gov (United States)

    Zheng, Y; Chen, M; He, L; Marão, H F; Sun, D M; Zhou, J; Kim, S G; Song, S; Wang, S L; Mao, J J

    2015-06-01

    Dentin in permanent teeth rarely undergoes resorption in development, homeostasis, or aging, in contrast to bone that undergoes periodic resorption/remodeling. The authors hypothesized that cells in the mesenchymal compartment of dental pulp attenuate osteoclastogenesis. Mononucleated and adherent cells from donor-matched rat dental pulp (dental pulp cells [DPCs]) and alveolar bone (alveolar bone cells [ABCs]) were isolated and separately cocultured with primary rat splenocytes. Primary splenocytes readily aggregated and formed osteoclast-like cells in chemically defined osteoclastogenesis medium with 20 ng/mL of macrophage colony-stimulating factor (M-CSF) and 50 ng/mL of receptor activator of nuclear factor κB ligand (RANKL). Strikingly, DPCs attenuated osteoclastogenesis when cocultured with primary splenocytes, whereas ABCs slightly but significantly promoted osteoclastogenesis. DPCs yielded ~20-fold lower RANKL expression but >2-fold higher osteoprotegerin (OPG) expression than donor-matched ABCs, yielding a RANKL/OPG ratio of 41:1 (ABCs:DPCs). Vitamin D3 significantly promoted RANKL expression in ABCs and OPG in DPCs. In vivo, rat maxillary incisors were atraumatically extracted (without any tooth fractures), followed by retrograde pulpectomy to remove DPCs and immediate replantation into the extraction sockets to allow repopulation of the surgically treated root canal with periodontal and alveolar bone-derived cells. After 8 wk, multiple dentin/root resorption lacunae were present in root dentin with robust RANKL and OPG expression. There were areas of dentin resoprtion alternating with areas of osteodentin formation in root dentin surface in the observed 8 wk. These findings suggest that DPCs of the mesenchymal compartment have an innate ability to attenuate osteoclastogenesis and that this innate ability may be responsible for the absence of dentin resorption in homeostasis. Mesenchymal attenuation of dentin resorption may have implications in internal

  19. Attenuation Analysis and Acoustic Pressure Levels for Combined Absorptive Mufflers

    Directory of Open Access Journals (Sweden)

    Ovidiu Vasile

    2011-09-01

    Full Text Available The paper describes the pressure-wave propagation in a muffler for an internal combustion engine in case of two combined mufflers geometry. The approach is generally applicable to analyzing the damping of propagation of harmonic pressure waves. The paper purpose is to show finite elements analysis of both inductive and resistive damping in pressure acoustics. The main output is the attenuation and acoustic pressure levels for the frequency range 50 Hz–3000 Hz.

  20. Cavity Attenuated Phase Shift (CAPS) Monitor Instrument Handbook

    Energy Technology Data Exchange (ETDEWEB)

    Sedlacek, Arthur J. [Brookhaven National Lab. (BNL), Upton, NY (United States)

    2016-04-01

    The CAPS PMex monitor is a cavity attenuated phase shift extinction instrument. It operates as an optical extinction spectrometer, using a visible-light-emitting diode (LED) as the light source, a sample cell incorporating two high-reflectivity mirrors centered at the wavelength of the LED, and a vacuum photodiode detector. Its efficacy is based on the fact that aerosols are broadband scatterers and absorbers of light.

  1. Resveratrol Attenuates Copper-Induced Senescence by Improving Cellular Proteostasis

    Directory of Open Access Journals (Sweden)

    Liliana Matos

    2017-01-01

    Full Text Available Copper sulfate-induced premature senescence (CuSO4-SIPS consistently mimetized molecular mechanisms of replicative senescence, particularly at the endoplasmic reticulum proteostasis level. In fact, disruption of protein homeostasis has been associated to age-related cell/tissue dysfunction and human disorders susceptibility. Resveratrol is a polyphenolic compound with proved antiaging properties under particular conditions. In this setting, we aimed to evaluate resveratrol ability to attenuate cellular senescence induction and to unravel related molecular mechanisms. Using CuSO4-SIPS WI-38 fibroblasts, resveratrol is shown to attenuate typical senescence alterations on cell morphology, senescence-associated beta-galactosidase activity, and cell proliferation. The mechanisms implicated in this antisenescence effect seem to be independent of senescence-associated genes and proteins regulation but are reliant on cellular proteostasis improvement. In fact, resveratrol supplementation restores copper-induced increased protein content, attenuates BiP level, and reduces carbonylated and polyubiquitinated proteins by autophagy induction. Our data provide compelling evidence for the beneficial effects of resveratrol by mitigating CuSO4-SIPS stressful consequences by the modulation of protein quality control systems. These findings highlight the importance of a balanced cellular proteostasis and add further knowledge on molecular mechanisms mediating resveratrol antisenescence effects. Moreover, they contribute to identifying specific molecular targets whose modulation will prevent age-associated cell dysfunction and improve human healthspan.

  2. High Attenuation Rate for Shallow, Small Earthquakes in Japan

    Science.gov (United States)

    Si, Hongjun; Koketsu, Kazuki; Miyake, Hiroe

    2017-09-01

    We compared the attenuation characteristics of peak ground accelerations (PGAs) and velocities (PGVs) of strong motion from shallow, small earthquakes that occurred in Japan with those predicted by the equations of Si and Midorikawa (J Struct Constr Eng 523:63-70, 1999). The observed PGAs and PGVs at stations far from the seismic source decayed more rapidly than the predicted ones. The same tendencies have been reported for deep, moderate, and large earthquakes, but not for shallow, moderate, and large earthquakes. This indicates that the peak values of ground motion from shallow, small earthquakes attenuate more steeply than those from shallow, moderate or large earthquakes. To investigate the reason for this difference, we numerically simulated strong ground motion for point sources of M w 4 and 6 earthquakes using a 2D finite difference method. The analyses of the synthetic waveforms suggested that the above differences are caused by surface waves, which are predominant at stations far from the seismic source for shallow, moderate earthquakes but not for shallow, small earthquakes. Thus, although loss due to reflection at the boundaries of the discontinuous Earth structure occurs in all shallow earthquakes, the apparent attenuation rate for a moderate or large earthquake is essentially the same as that of body waves propagating in a homogeneous medium due to the dominance of surface waves.

  3. Surfactants attenuate gas embolism-induced thrombin production.

    Science.gov (United States)

    Eckmann, David M; Diamond, Scott L

    2004-01-01

    There are no pharmacologic strategies to prevent embolism bubble-induced blood clot formation. The authors conducted experiments to measure thrombin production in sheared whole blood in the presence and absence of bubbles and three surface-active compounds. Blood samples were obtained from six volunteers seven times. The thrombin-specific substrate Boc-VPR-MCA was added to citrated blood diluted with HEPES-buffered saline. Experimental groups were as follows: sparging (air microbubble embolization) with surfactant present; sparging alone; surfactant alone; and neither surfactant nor sparging. The surfactants were Dow Corning Antifoam 1510US, Perftoran, and Pluronic F-127. Blood was sheared by a cone-plate viscometer at 100 and 500 s-1 for 5, 10, and 20 min at 37 degrees C, pipetted into excess stop buffer, and evaluated fluorimetrically. Mean values of fluorescence intensity +/- SDs for each group were compared using ANOVA. Differences were considered significant at P Surfactant addition without sparging did not change thrombin production (P > 0.05). Surfactants attenuated thrombin production in sparged samples 31.8-70.9% (P Surfactants added before sparging attenuate thrombin production. Surfactants may have a clinical application to attenuate gas embolism-induced clotting.

  4. Adaptation with disturbance attenuation in nonlinear control systems

    Energy Technology Data Exchange (ETDEWEB)

    Basar, T. [Univ. of Illinois, Urbana, IL (United States)

    1997-12-31

    We present an optimization-based adaptive controller design for nonlinear systems exhibiting parametric as well as functional uncertainty. The approach involves the formulation of an appropriate cost functional that places positive weight on deviations from the achievement of desired objectives (such as tracking of a reference trajectory while the system exhibits good transient performance) and negative weight on the energy of the uncertainty. This cost functional also translates into a disturbance attenuation inequality which quantifies the effect of the presence of uncertainty on the desired objective, which in turn yields an interpretation for the optimizing control as one that optimally attenuates the disturbance, viewed as the collection of unknown parameters and unknown signals entering the system dynamics. In addition to this disturbance attenuation property, the controllers obtained also feature adaptation in the sense that they help with identification of the unknown parameters, even though this has not been set as the primary goal of the design. In spite of this adaptation/identification role, the controllers obtained are not of certainty-equivalent type, which means that the identification and the control phases of the design are not decoupled.

  5. Frequency-dependent attenuation of Love waves and its estimation

    Energy Technology Data Exchange (ETDEWEB)

    Xiao-Ping Li [Karlsruhe Univ. (T.H.) (Germany)

    1995-12-31

    Absorption analysis of Love channel waves plays an important role in in-seam seismic exploration, because the usefulness of this method in a particular locality depends on the rate at which Love-type channel waves are attenuated during the passage through the coal seam. In the absence of any evidence of reflections, it is always important to know at what range such features would have been detected in case of their presence. Obviously this is determined by the number of factor, for example, the distance and especially the absorption. By introducing the complex propagation functions into the known dispersion relation of Love waves for a simple symmetric homogeneous three-layered linear elastic model, the frequency-dependent attenuation relation can be explicitly given assuming that the quality factor of the coal (Q{sub {beta}1}) and the country rock (Q{sub {beta}2}) is constant, The attenuation coefficient of the Love waves becomes a non-linear function of the frequency because of the velocity dispersion. In this case the spectral ratio method can not be applied since it can only estimate the frequency-independent component Q. Therefore, a modification of the spectral ratio method is presented to inverse the frequency-dependent Q of Love-waves. (author). 7 refs., 3 figs

  6. Ultrasound attenuation as a quantitative measure of fracture healing

    Science.gov (United States)

    Gheduzzi, Sabina; Humphrey, Victor F.; Dodd, Simon P.; Cunningham, James L.; Miles, Anthony W.

    2004-10-01

    The monitoring of fracture healing still relies upon the judgment of callus formation and on the manual assessment of the stiffness of the fracture. A diagnostic tool capable of quantitatively measuring healing progression of a fracture would allow the fine-tuning of the treatment regime. Ultrasound attenuation measurements were adopted as a possible method of assessing the healing process in human long bones. The method involves exciting ultrasonic waves at 200 kHz in the bone and measuring the reradiation along the bone and across the fracture zone. Seven cadaveric femora were tested in vitro in intact form and after creating a transverse fracture by sawing through the cortex. The effects of five different fracture types were investigated. A partial fracture, corresponding to a 50% cut through the cortex, a closed fracture, and fractures of widths varying between 1, 2, and 4 mm were investigated. The introduction of a fracture was found to produce a dramatic effect on the amplitude of the signal. Ultrasound attenuation was found to be sensitive to the presence of a fracture, even when the fracture was well reduced. It would therefore appear feasible to adopt attenuation across a fracture as a quantitative measurement of fracture healing.

  7. Creating a collimated ultrasound beam in highly attenuating fluids.

    Science.gov (United States)

    Raeymaekers, Bart; Pantea, Cristian; Sinha, Dipen N

    2012-04-01

    We have devised a method, based on a parametric array concept, to create a low-frequency (300-500 kHz) collimated ultrasound beam in fluids highly attenuating to sound. This collimated beam serves as the basis for designing an ultrasound visualization system that can be used in the oil exploration industry for down-hole imaging in drilling fluids. We present the results of two different approaches to generating a collimated beam in three types of highly attenuating drilling mud. In the first approach, the drilling mud itself was used as a nonlinear mixing medium to create a parametric array. However, the short absorption length in mud limits the mixing length and, consequently, the resulting beam is weak and broad. In the second improved approach, the beam generation process was confined to a separate "frequency mixing tube" that contained an acoustically non-linear, low attenuation medium (e.g., water) that allowed establishing a usable parametric array in the mixing tube. A low-frequency collimated beam was thus created prior to its propagation into the drilling fluid. Using the latter technique, the penetration depth of the low frequency ultrasound beam in the drilling fluid was significantly extended. We also present measurements of acoustic nonlinearity in various types of drilling mud. Copyright © 2011 Elsevier B.V. All rights reserved.

  8. Cannabinoids attenuate cancer pain and proliferation in a mouse model.

    Science.gov (United States)

    Saghafi, Negin; Lam, David K; Schmidt, Brian L

    2011-01-25

    We investigated the effects of cannabinoid receptor agonists on (1) oral cancer cell viability in vitro and (2) oral cancer pain and tumor growth in a mouse cancer model. We utilized immunohistochemistry and Western blot to show that human oral cancer cells express CBr1 and CBr2. When treated with WIN55,212-2 (non-selective), ACEA (CBr1-selective) or AM1241 (CBr2-selective) agonists in vitro, oral cancer cell proliferation was significantly attenuated in a dose-dependent manner. In vivo, systemic administration (0.013M) of WIN55,212-2, ACEA, or AM1241 significantly attenuated cancer-induced mechanical allodynia. Tumor growth was also significantly attenuated with systemic AM1241 administration. Our findings suggest a direct role for cannabinoid mechanisms in oral cancer pain and proliferation. The systemic administration of cannabinoid receptor agonists may have important therapeutic implications wherein cannabinoid receptor agonists may reduce morbidity and mortality of oral cancer. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  9. Terahertz attenuators based on dielectric stacks with alternating refractive indices

    Science.gov (United States)

    Dutta, Moumita; Peralta, Xomalin G.; Bhalla, Amar S.; Guo, Ruyan

    2017-10-01

    This article demonstrates the design of dielectric terahertz (THz) attenuators comprising of periodically placed x-cut and z-cut ion-sliced lithium niobate dielectric layers. Changes introduced in the propagating wave due to alternating refractive indices of a ferroelectric material have been exploited for the design of an effective attenuator. The electrical and optical properties gathered from experimental investigations have been used to study the influence of different crystalline orientations on the design. The conduit comprising the periodically placed dielectric slabs has been configured as a tristate switch by modulating the amplitude of the traversing THz wave by altering its angle of incidence. Full-wave finite-element simulations have been conducted over a series of parametric configurations to come up with the optimized design. A modulation depth as high as 94.76% is achieved. The proposed low-cost, easily configurable THz dielectric attenuators operating around 0.625 THz can be potentially used as an external modulator for THz quantum cascade lasers.

  10. Stress-Associated Intrinsic and Scattering Attenuation from Laboratory Ultrasonic Measurements on Shales

    Science.gov (United States)

    Hu, Junhua; Fu, Li-Yun; Wei, Wei; Zhang, Yan

    2017-10-01

    Seismic attenuation is sensitive to stress-induced subtle changes in the physical state of rocks. In this study, the stress- and frequency-associated attenuation is quantified through ultrasonic measurements on three differently oriented cylindrical shale samples under various axial stresses. As an improvement to the single-scattering model, the elastic Monte Carlo method is employed to investigate multiple-scattering attenuations by incorporating the boundary reflections and wave conversions. Our results show that, as the axial stress increases, the intrinsic attenuation decreases in all directions, while the scattering attenuation decreases slightly in the direction perpendicular to the bedding but increases largely and nonlinearly in other directions. These discrepancies result from different attenuation mechanisms. Both the intrinsic and scattering attenuation are found to be largest in the direction 45° to the bedding, but least in the perpendicular direction. The S-wave attenuation is larger and more sensitive to stress changes than P-wave attenuation due to its shorter wavelength. As expected from sandstone examples, the scattering attenuation in shales is significantly larger and more sensitive to stress changes than the intrinsic attenuation. The frequency dependence of scattering attenuation suggests that the peak frequency with the maximum scattering attenuation is independent of axial stresses, but varies in different directions of an individual rock with different heterogeneity and anisotropy scales. The peak frequency of S-coda is smaller and its peak scattering attenuation is larger than P-coda. In conclusion, the stress and frequency dependence of ultrasonic attenuations in shales differ largely in various directions, indicating significant anisotropy and heterogeneity.

  11. Optimal precision in ultrasound attenuation estimation and application to the detection of Duchenne muscular dystrophy carriers.

    Science.gov (United States)

    Berger, G; Laugier, P; Fink, M; Perrin, J

    1987-01-01

    This paper deals with the measurement of the attenuation of ultrasound in muscle and its application to the detection of Duchenne Muscular Dystrophy (DMD) carriers. The precision obtained when measuring the attenuation is an important parameter to be considered. A statistical approach is taken on simulated data and compared to in vivo results. The results allow discussion for the minimum tissue volume needed for the estimation. Variations in muscle attenuation between normals were obtained from studies on 27 volunteers. These attenuation values were compared to those obtained from 19 carriers of DMD. Attenuation appears to be a potential clinical indicator of DMD carriers.

  12. Monitored Natural Attenuation and Enhanced Attenuation for Chlorinated Solvent Plumes - It’s All About Balance

    Energy Technology Data Exchange (ETDEWEB)

    VANGELAS, KAREN

    2005-05-19

    Nature's inherent ability to cleanse itself is at the heart of Monitored Natural Attenuation (MNA). The complexity comes when one attempts to measure and calculate this inherent ability, called the Natural Attenuation Capacity (NAC), and determine if it is sufficient to cleanse the system to agreed upon criteria. An approach that is simple in concept for determining whether the NAC is sufficient for MNA to work is the concept of a mass balance. Mass balance is a robust framework upon which all decisions can be made. The inflows to and outflows from the system are balanced against the NAC of the subsurface system. For MNA to be acceptable, the NAC is balanced against the contaminant loading to the subsurface system with the resulting outflow from the system being in a range that is acceptable to the regulating and decision-making parties. When the system is such that the resulting outflow is not within an acceptable range, the idea of taking actions that are sustainable and that will bring the system within the acceptable range of outflows is evaluated. These sustainable enhancements are being developed under the Enhanced Attenuation (EA) concept.

  13. Characterization of Small Focal Renal Lesions: Diagnostic Accuracy with Single-Phase Contrast-enhanced Dual-Energy CT with Material Attenuation Analysis Compared with Conventional Attenuation Measurements.

    Science.gov (United States)

    Marin, Daniele; Davis, Drew; Roy Choudhury, Kingshuk; Patel, Bhavik; Gupta, Rajan T; Mileto, Achille; Nelson, Rendon C

    2017-09-01

    Purpose To determine whether single-phase contrast material-enhanced dual-energy material attenuation analysis improves the characterization of small (1-4 cm) renal lesions compared with conventional attenuation measurements by using histopathologic analysis and follow-up imaging as the clinical reference standards. Materials and Methods In this retrospective, HIPAA-compliant, institutional review board-approved study, 136 consecutive patients (95 men and 41 women; mean age, 54 years) with 144 renal lesions (111 benign, 33 malignant) measuring 1-4 cm underwent single-energy unenhanced and contrast-enhanced dual-energy computed tomography (CT) of the abdomen. For each renal lesion, attenuation measurements were obtained; attenuation change of greater than or equal to 15 HU was considered evidence of enhancement. Dual-energy attenuation measurements were also obtained by using iodine-water, water-iodine, calcium-water, and water-calcium material basis pairs. Mean lesion attenuation values and material densities were compared between benign and malignant renal lesions by using the two-sample t test. Diagnostic accuracy of attenuation measurements and dual-energy material densities was assessed and validated by using 10-fold cross-validation to limit the effect of optimistic bias. Results By using cross-validated optimal thresholds at 100% sensitivity, iodine-water material attenuation images significantly improved specificity for differentiating between benign and malignant renal lesions compared with conventional enhancement measurements (93% [103 of 111]; 95% confidence interval: 86%, 97%; vs 81% [90 of 111]; 95% confidence interval: 73%, 88%) (P = .02). Sensitivity with iodine-water and calcium-water material attenuation images was also higher than that with conventional enhancement measurements, although the difference was not statistically significant. Conclusion Contrast-enhanced dual-energy CT with material attenuation analysis improves specificity for

  14. Modeling Natural Attenuation of an Industrial Facility in Houston

    Science.gov (United States)

    Sun, D.

    2016-12-01

    Groundwater monitoring is currently ongoing at a commercial/industrial facility located in Deer Park, Texas (the site). The subject site is an approximate 10 acre commercial/industrial facility that began operation in the late-1970s. Operations have historically consisted of vehicle maintenance services, administrative, and equipment storage. Assessment and groundwater monitoring activities have been conducted at the site to evaluate the magnitude and extent of groundwater affected with chlorinated volatile organic compounds (VOCs). Groundwater data has been collected at this site since the mid-2000s on a quarterly basis. Presently, VOC constituents tetrachloroethene (PCE), trichloroethene (TCE), cis-1,2-dichloroethene (DCE), 1,1-dichloroethene (1,1-DCE), and vinyl chloride (VC) are the only chemicals of concern (COCs) detected at concentrations exceeding the TCEQ Actions Levels established by the state of Texas. The goal is that one day the site will receive a certificate of completion from the state, which states that all non-responsible parties are released from all liability to the state for cleanup. The remediation technology that is currently being used at this site is Monitoring Natural Attenuation (MNA). A significant question is whether MNA is efficiently removing COCs in groundwater and how long will this process take to achieve the remediation goals. The objective of this study is to provide an estimate of concentrations of COCs in groundwater at the site using the Biochlor model. The Biochlor model will help answer the question as to whether or not natural attenuation is occurring at the site efficiently. Results show that Monitored Natural Attenuation may not be the optimal remediation technology to use at this site. Other remedial technologies are needed to clean up chemical in the site. Groundwater monitoring is currently ongoing at a commercial/industrial facility located in Deer Park, Texas (the site). The subject site is an approximate 10 acre

  15. Losartan Attenuates Scar Formation in Filtering Bleb After Trabeculectomy.

    Science.gov (United States)

    Shi, Huimin; Wang, Huiying; Fu, Shuhao; Xu, Kang; Zhang, Xiaoyan; Xiao, Yiqin; Ye, Wen

    2017-03-01

    To examine the effects of losartan on scar formation after trabeculectomy and on fibrotic changes of human Tenon's fibroblasts (HTFs). Trabeculectomy was performed on New Zealand rabbits. They were randomized to receive one of the following treatments: 0.9% normal saline, mitomycin-C, or one of the three doses of losartan. Bleb morphology, IOP, and histopathology examination were performed. Primary cultured HTFs were treated with losartan or vehicle, with or without angiotensin II (Ang II). Cell proliferation was assessed by Cell Counting Kit-8 assay, and cell migration was detected by scratch wound and transwell assay. Transdifferentiation was evaluated through the expression of α-smooth muscle actin (α-SMA) by immunofluorescence, real-time PCR, and Western blot. The expression of fibronectin (FN) was evaluated by real-time PCR and Western blot. An amount of 5 mg/mL of losartan subconjunctival injection significantly decreased IOP postoperatively and attenuated wound healing of the filtering bleb in the rabbit model. Immunostaining results showed less myofibroblast and collagen deposition around the bleb area in the losartan-treated eyes. Losartan (10-5 M) in vitro significantly attenuated Ang II's stimulatory effects on proliferation and migration of HTFs. Expressions of α-SMA and FN in these cells were also decreased by losartan pretreatment. Losartan attenuates scar formation of filtering bleb after trabeculectomy likely via decreasing proliferation, migration, transdifferentiation, and extracellular matrix deposition of Tenon's fibroblasts. These results indicate that losartan may be an effective therapeutic agent in preventing bleb scar formation and in improving surgical outcome after trabeculectomy.

  16. Natural Attenuation-Untersuchungen 〝ehemalige Abfalldeponie Osterhofen``

    Science.gov (United States)

    Rügner, Hermann; Holder, Thomas; Maier, Uli; Bayer-Raich, Marti; Grathwohl, Peter; Teutsch, Georg

    Kurzfassung Im Abstrom der 〝ehemaligen Abfalldeponie Osterhofen`` wurden Konzentrationen an Ammonium festgestellt, die deutlich über dem in Baden-Württemberg geltenden Prüfwert liegen. Im Rahmen detaillierter Natural Attenuation (NA) Untersuchungen wurde überprüft, inwieweit die Nutzung mikrobiologischer Abbau- und Rückhalteprozesse des Ammoniums eine geeignete Entscheidungsoption für den Standort darstellt. Das Ergebnis der hierbei im Wesentlichen durchgeführten Frachtbestimmungen (mittels Immissionspumpversuchen) sowie einer konzeptionellen numerischen Modellierung des Ammoniumabbaues am Standort war, dass ein mikrobiologischer Abbau des Ammoniums zu Nitrat stattfindet (70-85 % Abbau innerhalb einer Distanz von ca. 450 m), dass allerdings aufgrund der diffusiv-/dispersiv bedingten langsamen Zufuhr von Sauerstoff in die Abstromfahne ein insgesamt ca. 550-680 m langer, stationärer Reaktionsraum existiert. Eine Gefahr für das Grundwasser im weiteren Abstrom der Deponie konnte ausgeschlossen werden. Eine gezielte Überwachung der NA-Prozesse kann am Standort an die Stelle einer aktiven Sanierungsmaßnahme treten. In groundwater downgradient of the former municipal landfill site ``Osterhofen'' concentrations of Ammonium much above the legal limit were detected. Based on detailed site investigations it was evaluated whether natural attenuation (NA) may be used as a contaminated land management option at the site. Investigations were mainly based on the determination of contaminant mass flow rates (by integral pumping tests) and numerical conceptual modelling of the ammonium degradation. As result it was found that biodegradation of ammonium is very effective (70-85 % degradation within a distance of approx. 450 m). Because oxygen supply into the plume is limited by transverse mixing a steady state plume of approx. 550-680 m in length exists. Since beyond this reactive zone no further risk for groundwater arises, monitored natural attenuation (MNA) is an

  17. Hybrid approach for attenuation correction in PET/MR scanners

    Energy Technology Data Exchange (ETDEWEB)

    Santos Ribeiro, A., E-mail: afribeiro@fc.ul.pt [Institute of Biophysics and Biomedical Engineering, Faculty of Sciences, University of Lisbon, Lisbon (Portugal); Rota Kops, E.; Herzog, H. [Institute of Neuroscience and Medicine, Forschungszentrum Juelich, Juelich (Germany); Almeida, P. [Institute of Biophysics and Biomedical Engineering, Faculty of Sciences, University of Lisbon, Lisbon (Portugal)

    2014-01-11

    Aim: Attenuation correction (AC) of PET images is still one of the major limitations of hybrid PET/MR scanners. Different methods have been proposed to obtain the AC map from morphological MR images. Although, segmentation methods normally fail to differentiate air and bone regions, while template or atlas methods usually cannot accurately represent regions anatomically different from the template image. In this study a feed forward neural network (FFNN) algorithm is presented which directly outputs the attenuation coefficients by non-linear regression of the images acquired with an ultrashort echo time (UTE) sequence guided by the template-based AC map (TAC-map). Materials and methods: MR as well as CT data were acquired in four subjects. The UTE images and the TAC-map were the inputs of the presented FFNN algorithm for training as well as classification. The resulting attenuation maps were compared with CT-based, PNN-based and TAC maps. All the AC maps were used to reconstruct the PET emission data which were then compared for the different methods. Results: For each subject dice coefficients D were calculated between each method and the respective CT-based AC maps. The resulting Ds show higher values for all FFNN-based tissues comparatively to both TAC-based and PNN-based methods, particularly for bone tissue (D=0.77, D=0.51 and D=0.71, respectively). The AC-corrected PET images with the FFNN-based map show an overall lower relative difference (RD=3.90%) than those AC-corrected with the PNN-based (RD=4.44%) or template-based (RD=4.43%) methods. Conclusion: Our results show that an enhancement of current methods can be performed by combining both information of new MR image sequence techniques and general information provided from template techniques. Nevertheless, the number of tested subjects is statistically low and current analysis for a larger dataset is being carried out.

  18. Intensive Exercise Training During Bed Rest Attenuates Deconditioning

    Science.gov (United States)

    Greenleaf, John E.

    1997-01-01

    Intensive exercise training during bed rest attenuates deconditioning. Med. Sci. Sports Exerc., Vol. 29, No. 2, pp. 207-215, 1997. A 30-d 6 deg head-down bed rest project was conducted to evaluate variable high-intensity, short-duration, isotonic cycle ergometer exercise (ITE) training and high-intensity intermittent resistive isokinetic exercise (IKE) training regimens designed to maintain peak VO2 and muscle mass, strength, and endurance at ambulatory control levels throughout prolonged bed rest. Other elements of the deconditioning (adaptive) syndrome, such as proprioception, psychological performance, hypovolemia, water balance, body composition, and orthostatic tolerance, were also measured. Major findings are summarized in this paper. Compared with response during bed rest of the no exercise (NOE) control group: the ITE training regimen (a) maintained work capacity (peak VO2), (b) maintained plasma and red cell volumes, (c) induced positive body water balance, (d) decreased quality of sleep and mental concentration, and (e) had no effect on the decrease in orthostatic tolerance; the IKE training regimen (f) attenuated the decrease in peak VO2 by 50%, (g) attenuated loss of red cell volume by 40% but had no effect on loss of plasma volume, (b) induced positive body water balance, (i) had no adverse effect on quality of sleep or concentration, and 0) had no effect on the decrease in orthostatic tolerance. These findings suggest that various elements of the deconditioning syndrome can be manipulated by duration and intensity of ITE or IKE training regimens and that several different training protocols will be required to maintain or restore physiological and psychological performance of individuals confined to prolonged bed rest.

  19. Attenuation of aortic aneurysms with stem cells from different genders.

    Science.gov (United States)

    Davis, John P; Salmon, Morgan; Pope, Nicolas H; Lu, Guanyi; Su, Gang; Sharma, Ashish K; Ailawadi, Gorav; Upchurch, Gilbert R

    2015-11-01

    No medical therapies are yet available to slow abdominal aortic aneurysm (AAA) growth. This study sought to investigate the effect of different genders of bone marrow-derived mesenchymal stem cells (MSC) on AAA growth in a murine AAA model. Given the decreased rate of AAA in women, it is hypothesized that female MSC would attenuate AAA growth more so than male MSC. Aortas of 8-10-wk-old male C57Bl/6 mice were perfused with purified porcine pancreatic elastase to induce AAA formation. Bone marrow-derived MSC from male and female mice were dosed via tail vein injection (3 million cells per dose, 500 μL of volume per injection) on postaortic perfusion days 1, 3, and 5. Aortas were harvested after 14 d. Mean aortic dilation in the elastase group was 121 ± 5.2% (mean ± standard error of the mean), while male MSC inhibited AAA growth (87.8 ± 6.9%, P = 0.008) compared with that of elastase. Female MSC showed the most marked attenuation of AAA growth (75.2 ± 8.3% P = 0.0004). Proinflammatory cytokines tumor necrosis factor α, interleukin 1β, and monocyte chemotactic protein-1 (MCP-1) were only decreased in tissues treated with female MSC (P = 0.017, P = 0.001, and P < 0.0001, respectively, when compared with elastase). These data exhibit that female MSC more strongly attenuate AAA growth in the murine model. Furthermore, female MSC and male MSC inhibit proinflammatory cytokines at varying levels. The effects of MSC on aortic tissue offer a promising insight into biologic therapies for future medical treatment of AAAs in humans. Copyright © 2015 Elsevier Inc. All rights reserved.

  20. Attenuation in the dubbing and subtitling of The Green Mile

    Directory of Open Access Journals (Sweden)

    Lidia Rodríguez

    2015-12-01

    Full Text Available This paper is part of the doctoral thesis entitled “Critique of translation for film dubbing and subtitling from the perspective of discourse analysis. A study applied to "The Green Mile”, written by Ph.D. student Gabriela Saturnina Alanís Uresti, directed by Ph.D. Lidia Rodríguez. It is a qualitative and descriptive study where we contrasted The Green Mile - a 1999 Hollywood film, original in American English - with its translated versions: dubbed and subtitled into Spanish of Mexico. We start from the presupposition that in film translation, some references such as the ones related to sexual behaviors and offensive language are attenuated in order to be strategically polite. Specifically, we analyzed two mechanisms of attenuation: lexical selection whereby a euphemism is used, and discursive modalization. These mechanisms constitute strategies of linguistic, pragmatic and semiotic nature as they appear in original (OV, dubbed (DV and subtitled (SV versions; both in acoustic and visual channels. Therefore, we examine these occurrences on verbal, para-verbal, and non-verbal codes. The theoretical basis includes studies of attenuation, politeness, euphemisms, and linguistic taboos. This paper is based on methodological proposals by Gutiérrez (2008, Nájar (2009, Brown y Levinson (1987, Goffman (1967, Leech (1983, Fraser (1980 Haverkate (1994, Bravo (2001, Albelda (2010, (2005, Albelda y Briz (2010, Briz (2002a; 2002b, Allan y Burridge (2006, Chamizo (2008, Foucault (1987, Seiciuc (2010, Dubois (1969, Dubois et al (1973, and Rodríguez (2004.