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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. 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.

  3. Salicylic acid and salicylic acid glucoside in xylem sap of Brassica napus infected with Verticillium longisporum

    OpenAIRE

    Ratzinger, Astrid; Riediger, Nadine; von Tiedemann, Andreas; Karlovsky, Petr

    2009-01-01

    Salicylic acid (SA) and its glucoside (SAG) were detected in xylem sap of Brassica napus by HPLC–MS. Concentrations of SA and SAG in xylem sap from the root and hypocotyl of the plant, and in extracts of shoots above the hypocotyl, increased after infection with the vascular pathogen Verticillium longisporum. Both concentrations were correlated with disease severity assessed as the reduction in shoot length. Furthermore, SAG levels in shoot extracts were correlated with the amount of V. longi...

  4. Functional analysis of the tomato Ve resistance locus against Verticillium wilt

    NARCIS (Netherlands)

    Fradin, E.F.

    2011-01-01

    Verticillium dahliae, V. albo-atrum and V. longisporum are soil-borne plant pathogens that are responsible for Verticillium wilt diseases in temperate and subtropical regions. Collectively they can infect over 200 hosts, including many economically important crops. Chapter 1 is a “pathogen pro

  5. Genetic dissection of Verticillium wilt resistance mediated by tomato Ve1

    NARCIS (Netherlands)

    Fradin, E.F.; Zhang, Z.; Juarez Ayala, J.C.; Castroverde, C.C.M.; Nazar, R.N.; Robb, J.; Liu, Chun-Ming; Thomma, B.P.H.J.

    2009-01-01

    Vascular wilt diseases caused by soil-borne pathogens are among the most devastating plant diseases worldwide. The Verticillium genus includes vascular wilt pathogens with a wide host range. Although V. longisporum infects various hosts belonging to the Cruciferaceae, V. dahliae and V. albo-atrum ca

  6. "Cryptic" group-I introns in the nuclear SSU-rRNA gene of Verticillium dahliae.

    Science.gov (United States)

    Papaioannou, Ioannis A; Dimopoulou, Chrysoula D; Typas, Milton A

    2014-08-01

    Group-I introns are widespread--though irregularly distributed--in eukaryotic organisms, and they have been extensively used for discrimination and phylogenetic analyses. Within the Verticillium genus, which comprises important phytopathogenic fungi, a group-I intron was previously identified in the SSU-rRNA (18S) gene of only V. longisporum. In this work, we aimed at elucidating the SSU-located intron distribution in V. dahliae and other Verticillium species, and the assessment of heterogeneity regarding intron content among rDNA repeats of fungal strains. Using conserved PCR primers for the amplification of the SSU gene, a structurally similar novel intron (sub-group IC1) was detected in only a few V. dahliae isolates. However, when intron-specific primers were used for the screening of a diverse collection of Verticillium isolates that originally failed to produce intron-containing SSU amplicons, most were found to contain one or both intron types, at variable rDNA repeat numbers. This marked heterogeneity was confirmed with qRT-PCR by testing rDNA copy numbers (varying from 39 to 70 copies per haploid genome) and intron copy ratios in selected isolates. Our results demonstrate that (a) IC1 group-I introns are not specific to V. longisporum within the Verticillium genus, (b) V. dahliae isolates of vegetative compatibility groups (VCGs) 4A and 6, which bear the novel intron at most of their rDNA repeats, are closely related, and (c) there is considerable intra-genomic heterogeneity for the presence or absence of introns among the ribosomal repeats. These findings underline that distributions of introns in the highly heterogeneous repetitive rDNA complex should always be verified with sensitive methods to avoid misleading conclusions for the phylogeny of fungi and other organisms.

  7. Pathogenicity in Verticillium on strawberry plants

    OpenAIRE

    Schubert, P.; J. Golldack; Schwärzel, H.; Lentzsch, P.

    2008-01-01

    In the most common strawberry cv. ’Elsanta’, Verticillium infection can lead to rapid wilt and even death of plants. It is known, that a dead plant can be located directly beside vital ones. In a survey of 8 fields in Brandenburg, Mecklenburg- Vorpommern, Sachsen-Anhalt and Sachsen, 432 genotypes of Verticillium dahliae Kleb. were isolated from wilted and even vital plants from 8 fields and classified by PCR-fingerprints. For strawberries, the genotypes can be classified as apa...

  8. PCR primers that allow intergeneric differentiation of ascomycetes and their application to Verticillium spp.

    OpenAIRE

    Li, K N; Rouse, D. I.; German, T L

    1994-01-01

    A pair of conserved PCR primers, designated NMS1 and NMS2, that amplify a region in the mitochondrial small rRNA gene region were designed for fungi belonging to the class Ascomycetes. These primers were tested with members of eight fungal genera (Aspergillus, Fusarium, Magnaporthe, Mycospharella, Neurospora, Saccharomyces, Sclerotinia, Verticillium) and 10 Verticillium species (Verticillium albo-atrum, Verticillium chlamydosporium, Verticillium cinnebarium, Verticillium dahliae, Verticillium...

  9. Suppression of Verticillium Wilt of Olive by Pseudomonas fluorescens

    OpenAIRE

    Sanei, S. J.; Razavi, S. E.

    2011-01-01

    Protection of pathogen-free olive planting material from infection by Verticillium dahliae during plant propagation and/or at planting would help in the management of Verticillium wilt of olive. Despite the importance for rhizosphere functioning, rhizobacterial Pseudomonas spp. have been mainly studied in a cultivation-based manner. In this study, 8 isolates of Pseudomonas fluorescens obtained from roots of olive plants were tested for suppression of Verticillium wilt in nursery-produced oliv...

  10. Host Range Specificity in Verticillium dahliae.

    Science.gov (United States)

    Bhat, R G; Subbarao, K V

    1999-12-01

    ABSTRACT Verticillium dahliae isolates from artichoke, bell pepper, cabbage, cauliflower, chili pepper, cotton, eggplant, lettuce, mint, potato, strawberry, tomato, and watermelon and V. albo-atrum from alfalfa were evaluated for their pathogenicity on all 14 hosts. One-month-old seedlings were inoculated with a spore suspension of about 10(7) conidia per ml using a root-dip technique and incubated in the greenhouse. Disease incidence and severity, plant height, and root and shoot dry weights were recorded 6 weeks after inoculation. Bell pepper, cabbage, cauliflower, cotton, eggplant, and mint isolates exhibited host specificity and differential pathogenicity on other hosts, whereas isolates from artichoke, lettuce, potato, strawberry, tomato, and watermelon did not. Bell pepper was resistant to all Verticillium isolates except isolates from bell pepper and eggplant. Thus, host specificity exists in some isolates of V. dahliae. The same isolates were characterized for vegetative compatibility groups (VCGs) through complementation of nitrate nonutilizing (nit) mutants. Cabbage and cauliflower isolates did not produce nit mutants. The isolate from cotton belonged to VCG 1; isolates from bell pepper, eggplant, potato, and tomato, to VCG 4; and the remaining isolates, to VCG 2. These isolates were also analyzed using the random amplified polymorphic DNA (RAPD) method. Forty random primers were screened, and eighteen of them amplified DNA from Verticillium. Based on RAPD banding patterns, cabbage and cauliflower isolates formed a unique group, distinct from other V. dahliae and V. albo-atrum groups. Minor genetic variations were observed among V. dahliae isolates from other hosts, regardless of whether they were host specific or not. There was no correlation among pathogenicity, VCGs, and RAPD banding patterns. Even though the isolates belonged to different VCGs, they shared similar RAPD profiles. These results suggest that management of Verticillium wilt in some crops

  11. Phylogenetic analyses of phytopathogenic isolates of Verticillium spp.

    OpenAIRE

    Qin, Q M; Vallad, G E; Wu, B M; Subbarao, K. V.

    2006-01-01

    To better understand the genetic relationships between Verticillium dahliae isolates from lettuce and other phytopathogenic Verticillium spp. isolates from various hosts and geographic locations, the complete intergenic spacer (IGS) region of the nuclear ribosomal RNA gene (rDNA) and the beta-tubulin gene were amplified and sequenced. The sequences of the complete IGS region and the P-tubulin gene were used alone and in combination to infer genetic relationships among different isolates of Ve...

  12. Strawberry breeding improves genetic resistance to Verticillium wilt

    OpenAIRE

    Shaw, Douglas V; Gordon, Thomas R.; Larson, Kirk D; Gubler, W. Douglas; Hansen, John; KirkPatrick, Sharon C

    2010-01-01

    Since 1994, more than 480 genotypes from the UC strawberry breeding program have been screened for resistance to Verticillium dahliae Kleb., an important soil pathogen of strawberry. Genotypes for parents of subsequent generations have been chosen using a multiple-trait strategy that incorporates their Verticillium resistance rating. This selection strategy has increased resistance scores for the parents by 60%, and increased the percentage of moderately resistant genotypes from 35.0% in the ...

  13. Breeding and genetics of lettuce against race 2 of Verticillium wilt

    Science.gov (United States)

    Verticillium wilt, caused by the soil-borne fungus Verticillium dahliae, is a destructive disease of lettuce in California. Verticillium resistance 1 (Vr1) confers resistance to race 1 isolates but is defeated by race 2 isolates, which are predicted to increase in prevalence. Three Plant Introductio...

  14. Interfamily Transfer of Tomato Ve1 Mediates Verticillium Resistance in Arabidopsis

    NARCIS (Netherlands)

    Fradin, E.F.; Abd-El-Haliem, A.; Masini, L.; Berg, van den G.C.M.; Joosten, M.H.A.J.; Thomma, B.P.H.J.

    2011-01-01

    Vascular wilts caused by soil-borne fungal species of the Verticillium genus are devastating plant diseases. The most common species, Verticillium dahliae and Verticillium albo-atrum, have broad host ranges and are notoriously difficult to control. Therefore, genetic resistance is the preferred meth

  15. 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 fie

  16. RAPD Patterns Characteristic for VCGs of Cotton Verticillium Wilt Pathogen, Verticillium dahliae

    Institute of Scientific and Technical Information of China (English)

    WANG Ke-rong; CHEN Rui-hui

    2002-01-01

    Nine primers were employed to detect molecular polymorphisms in 103 Verticillium dahliae isolates that represent diverse groups of Vegetative Compatibility (VC). Our results showed that these isolates confer two distinctive RAPD groups (RPGs). RPG1, consists of isolates belonging to vegetative compatibility group Ⅰ (VCG Ⅰ), while RPG2 encompasses VCGⅡ and VCGⅣ. The genetic diversity associated with VCGⅢ was greater than that associated with VCG1. Five RAPD fragments, with frequencies more than 0.96 in VCG Ⅰ but less than 0.1 in VCGⅢ, produced characteristic fragments for VCG Ⅰ (defoliating type), suggesting strong correlation between RPGs and VCGs.

  17. 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

  18. Entomopathogenic potential of Verticillium and Acremonium species (Deuteromycotina: Hyphomycetes).

    Science.gov (United States)

    Steenberg, T; Humber, R A

    1999-05-01

    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 were not Verticillium lecanii despite a superficial resemblance to this common entomopathogen. The fungi were identified as Verticillium fusisporum, Verticillium 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. In general, V. lecanii was the most pathogenic species. Immature whiteflies appeared to be more susceptible to fungal infection than adult houseflies, and the host range for several of the fungi also included lesser mealworm. PMID:10222186

  19. Identification of Novel Virulence-Associated Proteins Secreted to Xylem by Verticillium nonalfalfae During Colonization of Hop Plants.

    Science.gov (United States)

    Flajsman, Marko; Mandelc, Stanislav; Radisek, Sebastjan; Stajner, Natasa; Jakse, Jernej; Kosmelj, Katarina; Javornik, Branka

    2016-05-01

    Plant pathogens employ various secreted proteins to suppress host immunity for their successful host colonization. Identification and characterization of pathogen-secreted proteins can contribute to an understanding of the pathogenicity mechanism and help in disease control. We used proteomics to search for proteins secreted to xylem by the vascular pathogen Verticillium nonalfalfae during colonization of hop plants. Three highly abundant fungal proteins were identified: two enzymes, α-N-arabinofuranosidase (VnaAbf4.216) and peroxidase (VnaPRX1.1277), and one small secreted hypothetical protein (VnaSSP4.2). These are the first secreted proteins so far identified in xylem sap following infection with Verticillium spp. VnaPRX1.1277, classified as a heme-containing peroxidase from Class II, similar to other Verticillium spp. lignin-degrading peroxidases, and VnaSSP4.2, a 14-kDa cysteine-containing protein with unknown function and with a close homolog in related V. alfalfae strains, were further examined. The in planta expression of VnaPRX1.1277 and VnaSSP4.2 genes increased with the progression of colonization, implicating their role in fungal virulence. Indeed, V. nonalfalfae deletion mutants of both genes exhibited attenuated virulence on hop plants, which returned to the level of the wild-type pathogenicity in the knockout complementation lines, supporting VnaPRX1.1277 and VnaSSP4.2 as virulence factors required to promote V. nonalfalfae colonization of hop plants. PMID:26883488

  20. Efficacy of resistance selection to Verticillium wilt in strawberry (Fragaria x ananassa Duch.) tissue culture

    OpenAIRE

    Jadwiga I. Żebrowska

    2012-01-01

    The soil-borne pathogenic fungus Verticillium dahliae Kleb. causes economic losses in crops in temperate regions of the world and hence is the most studied species. Strawberry (Fragaria x ananassa Duch.) belongs to plant species susceptible to Verticillium dahliae, although the response to infection caused by this pathogen is varied and depends on the cultivar. Due to a lack of efficient methods in Verticillium wilt elimination, the selection of genetically resistant plant material is a prior...

  1. Genomics spurs rapid advances in our understanding of the biology of vascular wilt pathogens in the genus Verticillium

    NARCIS (Netherlands)

    Klimes, A.; Dobinson, K.F.; Thomma, B.; Klosterman, S.J.

    2015-01-01

    The availability of genomic sequences of several Verticillium species triggered an explosion of genome-scale investigations of mechanisms fundamental to the Verticillium life cycle and disease process. Comparative genomics studies have revealed evolutionary mechanisms, such as hybridization and inte

  2. Resistance to Verticillium dahliae (Kleb.) in the strawberry breeding lines.

    Science.gov (United States)

    Zebrowska, J; Hortyński, J; Cholewa, T; Honcz, K

    2006-01-01

    Verticillium species are soil-borne fungi with worldwide distribution, causing vascular disease that results in severe yield and quality losses in fruit and nut crops, legumes, vegetables, forest trees, and woody and herbaceous ornamentals. Most crop diseases are caused by the two species Verticillium dahliae Klebahn and V. albo-atrum Reinke and Berthier, which differ in morphology, host range, and growth characteristics. The control of Verticillium spp. is especially difficult because they can survive in the soil as resting structures for several years. Cultivation of resistant plant material is the most effective method of the disease elimination. Resistance to Verticillium dahliae Kleb. was examined in the four strawberry breeding lines i.e.'Kent S1', 'Kent o.p.', 'Plena S1', 'Plena o.p'. The strawberry isolate of cv. 'Elsanta' no.1093 of Verticillium dahliae from Pathogen Gene Bank (Poland-Poznań) was used throughout this study. Seedlings of strawberry breeding lines were used for in vitro inoculation at stage of 4 leaves. Their roots were dipped for approximately 1 min in conidial suspensions (inoculum concentration--60 spores at 100x magnification in the microscopic field). Observations of disease symptoms were performed at 15, 30, 45, 60 and 75 days post inoculation. Extent of leaf chlorosis was rated on a scale of 0-4 in which: 0 no symptom. 1 up to 25% chlorotic leaves. 2 up to 50% chlorotic leaves. 3 up to 75% chlorotic leaves. 4 up to 100% chlorotic leaves. Plant response to in vitro inoculation of V. dahliae was different and depended on the breeding line. The most susceptible breeding line was 'Plena S1' and the most resistant was the line 'Kent o.p'. The line 'Kent S1' was more susceptible than the last one, but much more resistant than the line 'Plena o.p'. Seedlings without disease symptoms were observed in all examined lines at 15 and 30 days post inoculation At 45 days post inoculation no plant without disease symptoms was observed. Disease

  3. Agronomic studies on the population dynamics of Verticillium dahliae.

    OpenAIRE

    Mol, L.

    1995-01-01

    Verticillium dahliae reduces crop yields by causing early senescence. The fungus survives in the soil as microsclerotia formed on senescing tissue of colonised plant parts. V.dahliae is endemic in many soils because of the high potential survival of its microsclerotia and its wide host range. The primary aim of the research was to investigate the feasability of reducing the inoculum density in the soil by stimulating the microsclerotia to germinate. A second aim was to quantify the formation ...

  4. Pathogenicity, vegetative compatibility, and genetic diversity in verticillium dahliae from sugar beet and historical strains

    Science.gov (United States)

    Verticillium wilt of sugar beet is a disease problem that has received very little attention in the literature, but has been reported to reduce sucrose production and purity. To improve our understanding of Verticillium wilt, a survey of sugar beet plants with wilt symptoms (leaves with yellow or n...

  5. Evaluation of verticillium wilt resistance in commercial cultivars and advanced breeding lines of cotton

    Science.gov (United States)

    Verticillium wilt (VW), caused by Verticillium dahliae Kleb, is one of the most destructive diseases in cotton (Gossypium spp.). The most efficient and cost-effective method of controlling the disease is the use of resistant cotton cultivars. Most commercial cultivars and elite breeding lines are de...

  6. Screening of wild and cultivated Capsicum germplasm reveals new sources of Verticillium wilt resistance

    Science.gov (United States)

    Verticillium wilt caused by Verticillium dahliae is an important soilborne disease of pepper (Capsicum species) worldwide. Most commercial pepper cultivars lack resistance to this pathogen. Our objective was to identify resistance to multiple V. dahliae isolates in wild and cultivated Capsicum acces...

  7. Using comparative genomics to develop a new model of understanding Verticillium wilt resistance in potato

    Science.gov (United States)

    Verticillium wilt (VW) is a persistent and costly disease affecting potato production. VW is caused by the soilborne fungi Verticillium dahliae and V. albo-atrum. Because of the difficulty in dealing with this disease, host resistance offers a low input, effective method of control. Most potato cult...

  8. Genetics of the partial resistance against race 2 of Verticillium dahliae in lettuce

    Science.gov (United States)

    Lettuce (Lactuca sativa L.) production on the Coastal California is threatened by Verticillium wilt, a soil borne fungal disease caused by Verticillium dahliae that diminishes yield and quality. Two races of V. dahliae were identified on lettuce, race 1 and race 2. Complete resistance to race 1 is c...

  9. Mutational analysis of the Ve1 immune receptor that mediates Verticillium resistance in tomato

    NARCIS (Netherlands)

    Zhang, Z.; Song, Y.; Liu, Chun-Ming; Thomma, B.P.H.J.

    2014-01-01

    Pathogenic Verticillium species are economically important plant pathogens that cause vascular wilt diseases in hundreds of plant species. The Ve1 gene of tomato confers resistance against race 1 strains of Verticillium dahliae and V. albo-atrum. Ve1 encodes an extracellular leucine-rich repeat (eLR

  10. 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.

  11. Assessment of Tolerance Level of some Cotton (Gossypium hirsutum L. Varieties against Verticillium wilt (Verticillium dahliae Kleb. Disease

    Directory of Open Access Journals (Sweden)

    Emine KARADEMIR

    2010-06-01

    Full Text Available The objective of this study was to assess the tolerance level of some cotton varieties against Verticillium wilt (Verticillium dahliae Kleb. disease. Verticillium wilt is one of the major constraint diseases of cotton production worldwide and also in Turkey. The study was carried out at the Southeastern Anatolia Agricultural Research Institute’s naturally infected experimental area during 2004-2006. In this study, 10 different commercial cotton varieties were used as plant material. The experimental design was a randomized complete-block with four replications. During the cotton growing season, foliar disease index (FDI, vascular disease index (VDI and vascular disease rate (VDR were observed in addition to seed cotton yield and some fiber quality characteristics. According to the results, it was determined that with regards to FDI, VDI and VDR, the most tolerant varieties were ‘GW-Teks’, ‘GW-Golda’ and ‘Carmen’, while the most sensitive varieties were ‘Maraş 92’, ‘Sayar 314’ and ‘Stoneville 453’. The other varieties had moderate tolerance levels. The highest seed cotton yield and lint yield were obtained from ‘DP-Deltaopal’ and ‘Stoneville 453’. These results showed that some sensitive varieties had high yield; the reason for this situation may be related with early or late occurrence of the disease. The result of this study indicated that ‘GW-Teks’, ‘GW-Golda’ and ‘Carmen’ varieties must be preferred for infected areas; on the other hand, ‘DP-Deltaopal’ and ‘Stoneville 453’ can be recommended and grown in uninfected areas. Additionally, ‘Carmen’, ‘GW-Teks’ and ‘GW-Golda’ varieties can be used as material for improving disease resistance in cotton breeding programs.

  12. Molecular Cloning and Characterization of Genes Involved in Cotton (Gossypium barbadense L.) Response to Verticillium dahliae

    Institute of Scientific and Technical Information of China (English)

    XU Li; ZHANG Xian-long; ZHU Long-fu; TU Li-li

    2008-01-01

    @@ Verticillium dahliae Kleb.is a necrotrophic plant pathogen which causes serious soil borne vascular disease in cotton.The molecular basis the defense response of cotton to this pathogen is poorly understood.

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

    DEFF Research Database (Denmark)

    Steenberg, Tove; Humber, Richard A

    1999-01-01

    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....... In general, V. lecanii was the most pathogenic species. Immature whiteflies appeared to be more susceptible to fungal infection than adult houseflies, and the host range for several of the fungi also included lesser mealworm....

  14. Mapping QTL associated with Verticillium dahliae resistance in the cultivated strawberry (Fragaria × ananassa)

    OpenAIRE

    L Antanaviciute; Šurbanovski, N; Harrison, N.; K J McLeary; Simpson, D. W.; Wilson, F.; Sargent, D.J.; Harrison, R. J.

    2015-01-01

    A biparental cross of octoploid strawberry segregating for resistance to Verticillium dahliae, the causative agent of Verticillium wilt, was screened under field conditions for three seasons. Average wilt scores were significantly associated with multiple QTL, which were mostly significant across all years. Markers significantly associated with the traits were used to screen material with known wilt resistance and susceptibility phenotypes. A clear and statistically significant relationship w...

  15. Impact of Plant Species and Site on Rhizosphere-Associated Fungi Antagonistic to Verticillium dahliae Kleb.

    OpenAIRE

    Berg, Gabriele; Zachow, Christin; Lottmann, Jana; Götz, Monika; Costa, Rodrigo; Smalla, Kornelia

    2005-01-01

    Fungi with antagonistic activity toward plant pathogens play an essential role in plant growth and health. To analyze the effects of the plant species and the site on the abundance and composition of fungi with antagonistic activity toward Verticillium dahliae, fungi were isolated from oilseed rape and strawberry rhizosphere and bulk soil from three different locations in Germany over two growing seasons. A total of 4,320 microfungi screened for in vitro antagonism toward Verticillium resulte...

  16. A study of interaction between Verticillium wilt Verticillium dahliae and root-knot nematode Meloidogyne javanica in olive cultivars.

    Science.gov (United States)

    Saeedizadeh, Ayatollah; Kheiri, Ahmad; Zad, Javad; Etebarian, Hasan Reza; Bandani, Ali Reza; Nasiri, Mohammad Bagher

    2009-01-01

    Second stage juvenile (J2) of root-knot nematode, Meloidogyne javanica, and microsclerotia of verticillium wilt, Verticillium dahliae, were used as the source of inoculum for nematode and fungus respectively. One-year-old seedlings of olive cultivars, Zard, Roghani, Koroneiki and Manzanilla, were transplanted to pots containing 2000g of sterilized sandy loam soil. Experiment was conducted in completely randomized design with 32 treatments and five replications. Treatments were as follows: control, nematode alone, fungus alone and fungus + nematode. Pots were inoculated with (0, 2000, 3000, 4000) J2 of nematode and/or (10 no/g soil) microsclerotia of fungus according to the treatments. Experiment was terminated after 10 months and fallowing parameters were determined i.e., fresh weight of root and stem, number of galls and egg masses per root system, and percentage of incidence of symptom on aerial parts, browning of vascular tissue, decrease of seedling height and stem/root tissue colonization by fungus. Results showed that presence of nematode caused reduction on colonization of the fungus in the root and stem and vice versa i.e. presence of fungus caused reduction on number of galls and egg masses produced by the nematode. Severe fungus wilt on aerial parts of Manzanilla cultivar was observed when both pathogens were inoculated and mild fungus wilt was observed in fungus alone treatments of Koroneiki cultivar. Galling and egg mass production in root system were reduced in cvs Manzanilla, Zard, Roghani and Koroneiki, respectively (p Manzanilla, respectively (p < or = 0/05). PMID:20222619

  17. Quantitative trait locus analysis of Verticillium wilt resistance in an introgressed recombinant inbred population of Upland cotton

    Science.gov (United States)

    Verticillium wilt (VW) of Upland cotton (Gossypium hirsutum L.) is caused by the soil-borne fungal pathogen Verticillium dahlia Kleb. The availability of VW-resistant cultivars is vital for control of this economically important disease, but there is a paucity of Upland cotton breeding lines and cul...

  18. Non-defoliating and defoliating strains from cotton correlate with races 1 and 2 of Verticillium dahliae

    Science.gov (United States)

    Verticillium wilt caused by Verticillium dahliae is an important disease of cotton worldwide. Isolates of V. dahliae can be characterized as race 1 or race 2 based on the responses of differential cultivars of tomato and lettuce or as defoliating or non-defoliating based on symptom expression in cot...

  19. Frequency of Verticillium species in commercial spinach fields and transmission of V. dahliae from spinach to subsequent lettuce crops

    Science.gov (United States)

    Verticillium wilt, caused by Verticillium dahlia,e is a devastating disease of lettuce in California. The disease on lettuce is currently restricted to a small geographic area in the central coastal California, even though cropping patterns in other coastal lettuce production regions in the state ar...

  20. 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...

  1. Fifteen years of verticillium wilt of lettuce in america’s salad bowl: a tale of immigration, subjugation and abatement.

    Science.gov (United States)

    Lettuce is a popular leafy vegetable that is globally cultivated. The US ranks second in production, with coastal California producing half of the US supply. In 1995, Verticillium wilt caused by the soil borne fungus Verticillium dahliae was identified as a disease of lettuce in coastal California, ...

  2. Genetic dissection of tetraploid cotton resistant to Verticillium wilt using interspecific chromosome segment introgression lines

    Institute of Scientific and Technical Information of China (English)

    Peng; Wang; Zhiyuan; Ning; Ling; Lin; Hong; Chen; Hongxian; Mei; Jun; Zhao; Bingliang; Liu; Xin; Zhang; Wangzhen; Guo; Tianzhen; Zhang

    2014-01-01

    Verticillium wilt(caused by the pathogen Verticillium dahliae) is of high concern for cotton producers and consumers. The major strategy for controlling this disease is the development of resistant cotton(Gossypium spp.) cultivars. We used interspecific chromosome segment introgression lines(CSILs) to identify quantitative trait loci(QTL) associated with resistance to Verticillium wilt in cotton grown in greenhouse and inoculated with three defoliating V. dahliae isolates. A total of 42 QTL, including 23 with resistance-increasing and 19 with resistancedecreasing, influenced host resistance against the three isolates. These QTL were identified and mapped on 18 chromosomes(chromosomes A1, A3, A4, A5, A7, A8, A9, A12, A13, D1, D2,D3, D4, D5, D7, D8, D11, and D12), with LOD values ranging from 3.00 to 9.29. Among the positive QTL with resistance-increasing effect, 21 conferred resistance to only one V. dahliae isolate, suggesting that resistance to V. dahliae conferred by most QTL is pathogen isolate-specific. The At subgenome of cotton had greater effect on resistance to Verticillium wilt than the Dt subgenome. We conclude that pyramiding different resistant QTL could be used to breed cotton cultivars with broad-spectrum resistance to Verticillium wilt.

  3. Cotton GhBAK1 Mediates Verticillium Wilt Resistance and Cell Death

    Institute of Scientific and Technical Information of China (English)

    Xiquan Gao; Fangjun Li; Maoying Li; Ali S.Kianinejad; Jane K.Dever; Terry A.Wheeler; Zhaohu LP

    2013-01-01

    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 hera that highly efficient VIGS was obtained in a cotton breeding line (CA4002) with partial resistance to Verticillium wilt,and GhMKK2 and Gh Ve 1 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.

  4. The effects of cotton root exudates on the growth and development of Verticillium dahliae

    Institute of Scientific and Technical Information of China (English)

    Yuxiang WU; Weiping FANG; Shuijin ZHU; Kuiying JIN; Daofan JI

    2008-01-01

    The effects of upland cotton root exudates on the growth and development of Verticillium dahliae were studied, through the compared analysis of the root exudates components between the resistant and suscept-ive cotton materials, using a pair of resistant and sus-ceptive isogenic lines to Verticillium wilt, Z5629 and Z421, as well as 4 other upland cotton cultivars with different resistant levels of Verticillium wilt. The results showed that the amino acids in the root exudates of the resistant cultivars were much less than that of the sus-ceptible ones. Compared with the susceptible ones, there were a lack of aspartic acid, threonine, glutamic acid, alanine, isoleucine, leucine, phenylalanine, lysine and proline in the root exudates from the resistant cul-tivars. On the contrary, arginine was lacking in the sus-ceptive cultivars. The saccharide types in the root exudates were no different between the two kinds of cultivars, but the contents of glucose, fructose and suc-rose in the root exudates of the susceptible varieties were much higher than those in the resistant ones. The experiment of Verticillium dahliae culture showed that the cotton root exudates from resistant cultivars can effectively restrain the spore germination and mycelium growth of Verticillium dahliae, and the argi-nine was the leading amino acid in this inhibitory action, besides the nutrition of the root exudates. However, the cotton root exudates from the susceptive cotton cultivars can improve the growth and develop-ment of Verticillium dahliae effectively; among the amino acid in the exudates, alanine was the most active one in this stimulating function.

  5. Studies on Cotton Breeding Resistant to Fusarium and Verticillium wilt Diseases

    Institute of Scientific and Technical Information of China (English)

    YE Peng-sheng; ZENG Hua-lan; WEI Shu-gu; ZHANG Yu; LI Qiong-ying

    2008-01-01

    @@ Both Fusarium and Verticillium wilts are important soil-borne diseases,which can not be effectively controlled by chemical fungicides.The two diseases,especially Verticillium wilt,have spread all over the cotton belt,and obstructed the progress of cotton production in China in recent years.It has been proven that breeding and growing resistant cultivars is one of the most economical and effective measures to control these diseases.The program of breeding cotton for resistance to wilt diseases has been continuously studied in Industrial Crops Research Institute,Sighuan Academy of Agricultural Sciences(ICRI-SAAS) for more than 50 years.

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

    Directory of Open Access Journals (Sweden)

    MARTINS-CORDER M.P.

    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.

  7. 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...

  8. 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 f

  9. 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...

  10. Verticillium dahliae Infects, Alters Plant Biomass, and Produces Inoculum on Rotation Crops.

    Science.gov (United States)

    Wheeler, D L; Johnson, D A

    2016-06-01

    Verticillium wilt, caused by Verticillium dahliae, reduces yields of potato and mint. Crop rotation is a potential management tactic for Verticillium wilt; however, the wide host range of V. dahliae may limit the effectiveness of this tactic. The hypothesis that rotation crops are infected by V. dahliae inoculum originating from potato and mint was tested by inoculation of mustards, grasses, and Austrian winter pea with eight isolates of V. dahliae. Inoculum density was estimated from plants and soil. Typical wilt symptoms were not observed in any rotation crop but plant biomass of some crops was reduced, not affected, or increased by infection of specific isolates. Each isolate was host-specific and infected a subset of the rotation crops tested but microsclerotia from at least one isolate were observed on each rotation crop. Some isolates were host-adapted and differentially altered plant biomass or produced differential amounts of inoculum on rotation crops like arugula and Austrian winter pea, which supported more inoculum of specific isolates than potato. Evidence of asymptomatic and symptomatic infection and differential inoculum formation of V. dahliae on rotation crops presented here will be useful in designing rotations for management of Verticillium wilt. PMID:26828231

  11. 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...

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

    Science.gov (United States)

    Many soil-inhabiting fungi are capable of surviving the dynamic soil microenvironment through the formation of resilient resting structures, such as thick-walled spores, melanized hyphae, and sclerotia. Verticillium dahliae is a soil-inhabiting, economically significant plant pathogenic fungus that ...

  13. Verticillium comparative genomics yields insights into niche adaptation by plant vascular wilt pathogens.

    Science.gov (United States)

    The vascular wilt fungi Verticillium dahliae and V. albo-atrum infect over 200 plant species, causing billions of dollars in annual losses. The characteristic vascular wilt symptoms are a result of colonization and proliferation of the pathogens in the xylem vessels. To gain insights into the mechan...

  14. Verticillium dahliae Infects, Alters Plant Biomass, and Produces Inoculum on Rotation Crops.

    Science.gov (United States)

    Wheeler, D L; Johnson, D A

    2016-06-01

    Verticillium wilt, caused by Verticillium dahliae, reduces yields of potato and mint. Crop rotation is a potential management tactic for Verticillium wilt; however, the wide host range of V. dahliae may limit the effectiveness of this tactic. The hypothesis that rotation crops are infected by V. dahliae inoculum originating from potato and mint was tested by inoculation of mustards, grasses, and Austrian winter pea with eight isolates of V. dahliae. Inoculum density was estimated from plants and soil. Typical wilt symptoms were not observed in any rotation crop but plant biomass of some crops was reduced, not affected, or increased by infection of specific isolates. Each isolate was host-specific and infected a subset of the rotation crops tested but microsclerotia from at least one isolate were observed on each rotation crop. Some isolates were host-adapted and differentially altered plant biomass or produced differential amounts of inoculum on rotation crops like arugula and Austrian winter pea, which supported more inoculum of specific isolates than potato. Evidence of asymptomatic and symptomatic infection and differential inoculum formation of V. dahliae on rotation crops presented here will be useful in designing rotations for management of Verticillium wilt.

  15. Efficacy of resistance selection to Verticillium wilt in strawberry (Fragaria x ananassa Duch. tissue culture

    Directory of Open Access Journals (Sweden)

    Jadwiga I. Żebrowska

    2012-12-01

    Full Text Available The soil-borne pathogenic fungus Verticillium dahliae Kleb. causes economic losses in crops in temperate regions of the world and hence is the most studied species. Strawberry (Fragaria x ananassa Duch. belongs to plant species susceptible to Verticillium dahliae, although the response to infection caused by this pathogen is varied and depends on the cultivar. Due to a lack of efficient methods in Verticillium wilt elimination, the selection of genetically resistant plant material is a priority direction in breeding programs. Efficacy of resistance selection to Verticillium dahliae Kleb. in strawberry tissue culture was examined on the basis of response to in vitro infection by this pathogenic fungus in two tissue cultured strawberry cultivars, i.e. 'Filon' and 'Teresa'. Culture was conducted for 16 months in an environmentally controlled growth room at 18-20°C, 60-70% relative humidity and light intensity of 100 µm E × m-2 × s-1 on a 16h light / 8h dark cycle. Subcultures were proliferated every 6 weeks on modified Murashige and Skoog medium. Four hundred microplants from each tissue cultured cultivar were inoculated under in vitro conditions at the 4-leaf stage with a homogenate of liquid mycelium of Verticillium dahliae serving as the selecting agent. Disease symptoms were observed at 15, 30, 45, 60, and 75th days post inoculation. The extent of leaf chlorosis was rated on a scale of 0-4. At day 75th post inoculation, the percentage of totally chlorotic plants in micropropagated cv. Teresa reached the value of 76.27%, whereas the proportion of such plants in inoculated tissue cultured cv. Filon reached the value of 89.40%. Also, the index of infection calculated for very severe disease symptoms in the subclone 'Teresa' reached the mean value lower when compared with that calculated for subclone 'Filon' (0.0962 and 0.1150, respectively. These results suggested that the micropropagated cv. Teresa exhibited higher genetic resistance to the

  16. Genotypic Resistance of F_1 Cotton Hybrids by Inoculation with Different Virulent Isolates of the Fungus Verticillium Dahliae Klebahn

    Institute of Scientific and Technical Information of China (English)

    AMANTURDIEV; Alisher; KIM; Robert

    2008-01-01

    The plant pathogen Verticillium dahliae causes severe cotton losses in Uzbekistan. To create cotton varieties that are resistant to the more virulent races of V.dahliae we wanted to determine genotypic

  17. Detection of Microsclerotia of Verticillium dahliae in Soil Samples and Prospects to Reduce the Inoculum Potential of the Fungus in the Soil

    OpenAIRE

    Robert Steffek; Andreas Spornberger; Josef Altenburger

    2006-01-01

    Verticillium dahliae causes a wilting disease in strawberries and is very destructive on the light, sandy soils prevailing in many Austrian strawberry regions. Our work aims at the testing and providing different strategies to control Verticillium in the field: 1) a soil test to check the presence of microsclerotia before planting; 2) testing new, Verticillium tolerant early season varieties as alternative to ‘Elsanta’ and 3) testing measures to reduce the microsclerotia content in the soil. ...

  18. Comparison of Crop Rotation for Verticillium Wilt Management and Effect on Pythium Species in Conventional and Organic Strawberry Production

    OpenAIRE

    Krishna V Subbarao

    2009-01-01

    The effects of broccoli and lettuce rotations on population densities of Verticillium dahliae and Pythium spp. in soil and on strawberry (Fragaria × ananassa) growth, yield, and Verticillium wilt were evaluated in conventional and organic production systems in California for 2 years. Under both management systems, strawberry was planted after two successive crops of broccoli or lettuce. The control treatment in the conventional field was strawberry planted in soils fumigated with methyl bromi...

  19. Mapping QTL associated with Verticillium dahliae resistance in the cultivated strawberry (Fragaria × ananassa).

    Science.gov (United States)

    Antanaviciute, L; Šurbanovski, N; Harrison, N; McLeary, K J; Simpson, D W; Wilson, F; Sargent, D J; Harrison, R J

    2015-01-01

    A biparental cross of octoploid strawberry segregating for resistance to Verticillium dahliae, the causative agent of Verticillium wilt, was screened under field conditions for three seasons. Average wilt scores were significantly associated with multiple QTL, which were mostly significant across all years. Markers significantly associated with the traits were used to screen material with known wilt resistance and susceptibility phenotypes. A clear and statistically significant relationship was observed between resistant, tolerant and susceptible material and the total number of markers present in the different resistance classes. In field situations resistance QTL appear to behave in an additive manner. These markers are abundant in the cultivated strawberry germplasm indicating that, despite the large number of markers, clear genetic gain is possible through marker-assisted breeding.

  20. Mapping QTL associated with Verticillium dahliae resistance in the cultivated strawberry (Fragaria × ananassa).

    Science.gov (United States)

    Antanaviciute, L; Šurbanovski, N; Harrison, N; McLeary, K J; Simpson, D W; Wilson, F; Sargent, D J; Harrison, R J

    2015-01-01

    A biparental cross of octoploid strawberry segregating for resistance to Verticillium dahliae, the causative agent of Verticillium wilt, was screened under field conditions for three seasons. Average wilt scores were significantly associated with multiple QTL, which were mostly significant across all years. Markers significantly associated with the traits were used to screen material with known wilt resistance and susceptibility phenotypes. A clear and statistically significant relationship was observed between resistant, tolerant and susceptible material and the total number of markers present in the different resistance classes. In field situations resistance QTL appear to behave in an additive manner. These markers are abundant in the cultivated strawberry germplasm indicating that, despite the large number of markers, clear genetic gain is possible through marker-assisted breeding. PMID:26504565

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

    OpenAIRE

    Jan Piotrowski; Marian Milczak

    2013-01-01

    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. ...

  2. Plant-dependent genotypic and phenotypic diversity of antagonistic rhizobacteria isolated from different Verticillium host plants.

    Science.gov (United States)

    Berg, Gabriele; Roskot, Nicolle; Steidle, Anette; Eberl, Leo; Zock, Angela; Smalla, Kornelia

    2002-07-01

    To study the effect of plant species on the abundance and diversity of bacterial antagonists, the abundance, the phenotypic diversity, and the genotypic diversity of rhizobacteria isolated from potato, oilseed rape, and strawberry and from bulk soil which showed antagonistic activity towards the soilborne pathogen Verticillium dahliae Kleb. were analyzed. Rhizosphere and soil samples were taken five times over two growing seasons in 1998 and 1999 from a randomized field trial. Bacterial isolates were obtained after plating on R2A (Difco, Detroit, Mich.) or enrichment in microtiter plates containing high-molecular-weight substrates followed by plating on R2A. A total of 5,854 bacteria isolated from the rhizosphere of strawberry, potato, or oilseed rape or bulk soil from fallow were screened by dual testing for in vitro antagonism towards VERTICILLIUM: The proportion of isolates with antagonistic activity was highest for strawberry rhizosphere (9.5%), followed by oilseed rape (6.3%), potato (3.7%), and soil (3.3%). The 331 Verticillium antagonists were identified by their fatty acid methyl ester profiles. They were characterized by testing their in vitro antagonism against other pathogenic fungi; their glucanolytic, chitinolytic, and proteolytic activities; and their BOX-PCR fingerprints. The abundance and composition of Verticillium antagonists was plant species dependent. A rather high proportion of antagonists from the strawberry rhizosphere was identified as Pseudomonas putida B (69%), while antagonists belonging to the Enterobacteriaceae (Serratia spp., Pantoea agglomerans) were mainly isolated from the rhizosphere of oilseed rape. For P. putida A and B plant-specific genotypes were observed, suggesting that these bacteria were specifically enriched in each rhizosphere. PMID:12089011

  3. Plant-Dependent Genotypic and Phenotypic Diversity of Antagonistic Rhizobacteria Isolated from Different Verticillium Host Plants

    OpenAIRE

    Berg, Gabriele; Roskot, Nicolle; Steidle, Anette; Eberl, Leo; Zock, Angela; Smalla, Kornelia

    2002-01-01

    To study the effect of plant species on the abundance and diversity of bacterial antagonists, the abundance, the phenotypic diversity, and the genotypic diversity of rhizobacteria isolated from potato, oilseed rape, and strawberry and from bulk soil which showed antagonistic activity towards the soilborne pathogen Verticillium dahliae Kleb. were analyzed. Rhizosphere and soil samples were taken five times over two growing seasons in 1998 and 1999 from a randomized field trial. Bacterial isola...

  4. Impact of plant species and site on rhizosphere-associated fungi antagonistic to Verticillium dahliae kleb.

    Science.gov (United States)

    Berg, Gabriele; Zachow, Christin; Lottmann, Jana; Götz, Monika; Costa, Rodrigo; Smalla, Kornelia

    2005-08-01

    Fungi with antagonistic activity toward plant pathogens play an essential role in plant growth and health. To analyze the effects of the plant species and the site on the abundance and composition of fungi with antagonistic activity toward Verticillium dahliae, fungi were isolated from oilseed rape and strawberry rhizosphere and bulk soil from three different locations in Germany over two growing seasons. A total of 4,320 microfungi screened for in vitro antagonism toward Verticillium resulted in 911 active isolates. This high proportion of fungi antagonistic toward the pathogen V. dahliae was found for bulk and rhizosphere soil at all sites. A plant- and site-dependent specificity of the composition of antagonistic morphotypes and their genotypic diversity was found. The strawberry rhizosphere was characterized by preferential occurrence of Penicillium and Paecilomyces isolates and low numbers of morphotypes (n = 31) and species (n = 13), while Monographella isolates were most frequently obtained from the rhizosphere of oilseed rape, for which higher numbers of morphotypes (n = 41) and species (n = 17) were found. Trichoderma strains displayed high diversity in all soils, but a high degree of plant specificity was shown by BOX-PCR fingerprints. The diversity of rhizosphere-associated antagonists was lower than that of antagonists in bulk soil, suggesting that some fungi were specifically enriched in each rhizosphere. A broad spectrum of new Verticillium antagonists was identified, and the implications of the data for biocontrol applications are discussed. PMID:16085804

  5. 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. PMID:11142403

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

    NARCIS (Netherlands)

    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 PIC

  7. VdCYC8, encoding CYC8 glucose repression mediator protein, is required for microsclerotia formation and full virulence in Verticillium dahliae

    Science.gov (United States)

    Verticillium dahliae is the primary causal agent for Verticillium wilt disease on a diverse array of economically important crops, including cotton. In previous research, we screened a T-DNA insertional mutant library of the highly virulent isolate Vd080 derived from cotton. In this study, the targ...

  8. 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.

  9. 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

  10. Physiological mechanisms involved in resistance to cotton verticillium wilt induced by AM fungi

    Institute of Scientific and Technical Information of China (English)

    LIU Bing-jiang; LIU Run-jin

    2004-01-01

    @@ It was proved that arbuscular mycorrhizal (AM) fungi played an important role in increasing plant resistance to soilborne pathogens, especially when plants were pre-inoculated with AM fungi.Mechanisms involved in this phenomenon are not yet well understood. On the basis of the former experiment results in our lab, effects of AM fungi on cotton Verticillium wilt and the mechanisms of increasing disease resisitance by the tested fungi were studied in pot culture under greenhouse conditions. Two cotton cutivars Litai 8 and 86-1 which are susceptible to Verticillium dahliae were pre-inoculated with Glomus fasiculatum, and Gigaspora margarita, then inoculated with the strain of Verticillium dahliae, namely "An-Yang" (belong to intermediate virulent type) 30 days after the former inoculation. Results showed that AM fungi could improve the growth and development of cotton plants, increase plants dry mass, decrease incidence and disease index of Verticillium wilt of cotton plants, inhibit the infection and development of V. dahliae to different extent in the rhizosphere of cotton pre-inoculated with AM fungi, while the colonization and spore numbers of AM fungi were not reduced significantly by this pathogen. The defence enzymes, such as phenylalanine ammonia-lyase (PAL), chitinase, β-1, 3-glucanase, peroxidase, polyphenoloxidase (PPO) were induced, and their activities and peak increased by AM fungi in roots and leaves, and the increasing speed and peak of the enzyme activity were higher in treatment with AM fungus preinoculation than the inoculation with only V. dahliae, which suggested that defense response was activated by AM fungi, and then made the cotton to react strongly and rapidly to the infection of V. dahliae. In addition, AM fungi decreased the content of malondiadehyde (MDA) in cotton roots and leaves,protected membrane system and alleviated the damage caused by the pathogen. The AM fungus,Glomus fasiculatum showed the superior effects of biological

  11. 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.

  12. 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

    2016-01-01

    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. PMID:26856318

  13. The genome of the saprophytic fungus Verticillium tricorpus reveals a complex effector repertoire largely resembling its pathogenic relatives

    Science.gov (United States)

    Vascular wilts belong to the most destructive plant diseases, affecting hundreds of economically and ecologically important plant species. The fungal genus Verticillium presently comprises ten species, of which only few are causal agents of vascular wilt diseases. Of these, V. dahliae is the most no...

  14. 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

    2016-01-01

    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. PMID:26856318

  15. 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.

    1989-01-01

    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 gro

  16. Mapping and Quantitative Trait Loci Analysis of Verticillium Wilt Resistance Genes in Cotton

    Institute of Scientific and Technical Information of China (English)

    Hong-Mei Wang; Zhong-Xu Lin; Xian-Long Zhang; Wei Chen; Xiao-Ping Guo; Yi-Chun Nie; Yun-Hai Li

    2008-01-01

    Verticillium wilt is one of the most serious constraints to cotton production in almost all of the cotton-growing countries. In this study, "XinLuZao1" (XLZ1), a susceptible cultivar Gossypium hirsutum L. and "Hai7124" (H7124), a resistant line G. barbadense, and their F2:3 families were used to map and study the disease Index induced by verticillium wilt. A total of 430 SSR loci were mapped into 41 linkage groups; the map spanned 3 745.9 cM and the average distance between adjacent loci was 8.71 cM. Four and five quantitative trait loci (QTLs) were detected based on the disease index investigated on July 22 and August 24 in 2004, respectively. These nine QTLs explained 10.63-28.83% of the phenotypic variance, six of them were located on the D sub-genome. Two QTLs located In the same marker intervals may partly explain the significant correlation of the two traits. QTLs explaining large phenotypic variation were identified in this study, which may be quite useful in cotton anti-disease breeding.

  17. Studies on the Pathogenicity Differentiation of Verticillium dahliae on Cotton Varieties

    Institute of Scientific and Technical Information of China (English)

    ZHOU Zhao-hua; ZHANG Tian-zhen; PAN Jia-ju; CHEN Zhao-xia; JIANG Wei-min

    2001-01-01

    Verticillium dahliae may be classified into the two basic groups, defoliate and non-defoliate, in terms of the pathogenicity reaction of 19 isolates of Verticillium dahliae on 16 cotton varieties. According to the comprehensive resistant or susceptible expression of 8 defoliate isolates on 8 upland cotton varieties R02,R04, R05, R06, R08, R09, R11 and R14, the defoliate isolates were for the first time divided into three categories: strong pathogenic (XS4 as the representative), mediun with inclination to strong pathogenic (T9 as the representative) and medium pathogenic (VD8 as the representative). Through the resistance identification of varieties such as R05, R06, R08, R09, R11 and R14, the defoliate isolate VD8 originated from Nantong of Jiangsu Province may be efficiently distinguished from the defoliate isolate 19 originated from USA. In nondefoliate category, utilizing 4 upland varieties R15, R14, R13 and R10, it might be possible to identify the different pathogenic genes in 7 isolates XJ4, XJ1, AY, VD404, VD326, LY, BP2 and may be nominated as No. 1 to No. 7 biological races respectively. The upland variety R01 is capable of resisting to all the isolates used in the experiments. While upland variety R12, may be used to identify strongly pathogenic isolate, which displayed a specific function in identifying strong pathogenic isolate strains.

  18. 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.

  19. Detection of Microsclerotia of Verticillium dahliae in Soil Samples and Prospects to Reduce the Inoculum Potential of the Fungus in the Soil

    Directory of Open Access Journals (Sweden)

    Robert Steffek

    2006-01-01

    Full Text Available Verticillium dahliae causes a wilting disease in strawberries and is very destructive on the light, sandy soils prevailing in many Austrian strawberry regions. Our work aims at the testing and providing different strategies to control Verticillium in the field: 1 a soil test to check the presence of microsclerotia before planting; 2 testing new, Verticillium tolerant early season varieties as alternative to ‘Elsanta’ and 3 testing measures to reduce the microsclerotia content in the soil. The paper describes a field monitoring to study the factors that influence the relationship between inoculum concentration in the soil and the disease incidence in the field, and on-farm biofumigation trials aiming at testing the applicability of the method to reduce the microsclerotia of Verticillium dahliae in the soil.

  20. Detection of Microsclerotia of Verticillium dahliae in Soil Samples and Prospects to Reduce the Inoculum Potential of the Fungus in the Soil

    Directory of Open Access Journals (Sweden)

    Robert Steffek

    2006-12-01

    Full Text Available Verticillium dahliae causes a wilting disease in strawberries and is very destructive on the light, sandy soils prevailing in many Austrian strawberry regions. Our work aims at the testing and providing different strategies to control Verticillium in the field: 1 a soil test to check the presence of microsclerotia before planting; 2 testing new, Verticillium tolerant early season varieties as alternative to ‘Elsanta’ and 3 testing measures to reduce the microsclerotia content in the soil. The paper describes a field monitoring to study the factors that influence the relationship between inoculum concentration in the soil and the disease incidence in the field, and on-farm biofumigation trials aiming at testing the applicability of the method to reduce the microsclerotia of Verticillium dahliae in the soil.

  1. Host specificity, but not high-temperature tolerance, is associated with recent outbreaks of Verticillium dahliae in chrysanthemum in the Netherlands

    OpenAIRE

    Ispahani, S.K.; Goud, J.C.; Termorshuizen, A.J.; Morton, A.; Barbara, D J

    2008-01-01

    Two hypotheses which might explain a recent increase in the incidence of verticillium wilt of chrysanthemums in glasshouses in the Netherlands were investigated, viz whether selection for increased resistance to elevated temperatures has occurred due to frequent steaming of soils in the glasshouses, or whether the strains of Verticillium dahliae occurring in chrysanthemum glasshouses are particularly virulent towards this host. Following artificial inoculation, five isolates of V. dahliae fro...

  2. Observação in vitro da ação dos isolados fúngicos Duddingtonia flagrans, Monacrosporium thaumasium e Verticillium chlamydosporium sobre ovos de Ascaris lumbricoides (Lineu, 1758) In vitro observation of the action of isolates of the fungi Duddingtonia flagrans, Monacrosporium thaumasium and Verticillium chlamydosporium on the eggs of Ascaris lumbricoides (Linnaeus, 1758)

    OpenAIRE

    Fábio R. Braga; Jackson V. Araújo; Artur K. Campos; Rogério O. Carvalho; André R. Silva; Alexandre O. Tavela; Alessandro S. Maciel

    2007-01-01

    Observou-se a ação in vitro dos fungos nematófagos Duddingtonia flagrans, Monacrosporium thaumasium e Verticillium chlamydosporium sobre ovos de Ascaris lumbricoides. Após sete, dez e quatorze dias de interação, o fungo promissor a ser utilizado no controle biológico de Asaris lumbricoides foi o Verticillium chlamydosporium (26-30%). Os outros fungos não foram satisfatórios.The in vitro action of the nematophagous fungi Duddingtonia flagrans, Monacrosporium thaumasium and Verticillium chlamyd...

  3. 高效大丽轮枝菌(Verticillium dahliae)基因敲除体系的构建%High efficient gene knockout in Verticillium dahliae

    Institute of Scientific and Technical Information of China (English)

    田李; 陈捷胤; 汪佳妮; 王金龙; 戴小枫

    2011-01-01

    [目的]为了深入研究大丽轮枝菌(Verticillium dahliae)致病基因的功能,构建高效大丽轮枝菌基因敲除体系.[方法]融合PCR构建基因敲除载体;利用农杆菌介导法转化大丽轮枝菌;使用在T-DNA之间加入致死基因的双元载体,使T-DNA随机插入转化子在添加5-氟脱氧尿苷的培养基上不能存活,实现对随机插入转化子的"反向筛选".[结果]对大丽轮枝菌腺嘌呤合成酶基因和几丁质合成酶基因进行基因敲除验证,基因敲除转化子在总转化子中的比例分别达到87%和44%.[结论]成功构建大丽轮枝菌高效基因敲除体系,为大丽轮枝菌致病基因的功能验证提供了技术平台.

  4. THE INSECT PATHOGENIC FUNGUS Verticillium lecanii (Zimm. Viegas AND ITS USE FOR PESTS CONTROL: A REVIEW

    Directory of Open Access Journals (Sweden)

    Thiery B C ALAVO

    2015-08-01

    Full Text Available Chemical insecticides play an important role in the control of plant damage and plant diseases. However, extensive use of these products has led to the disruption of ecosystems because of several reasons such as death of non-target species, accumulation of pesticide residues in the environment and food, and buildup of pesticide resistance in the target species. Biological control is one of the alternatives to chemical pesticides and it can be described as the limitation of the abundance of living organisms and their products by other living organisms. Predators, parasitoids, fungi and other beneficial organisms can be used for the biocontrol of insect pests. The fungus Verticillium lecanii is one of the members of Deuteromycetes and it can be used for crop protection. This paper is a review of the international literature related to V. lecanii for the bio-control of insects of agricultural importance.

  5. Fungicide sensitivity of selected Verticillium fungicola isolates from Agaricus bisporus farms

    Directory of Open Access Journals (Sweden)

    Potočnik Ivana

    2008-01-01

    Full Text Available Five isolates of Verticillium fungicola, isolated from diseased fruiting bodies of Agaricus bisporus collected from mushroom farms in Serbia during 2002-2003, were studied. By observing their colony morphology under different growth conditions and their pathogenic characteristics, the isolates were identified as V. fungicola var. fungicola. The peat/lime casing was the primary source of infection. Testing of sensitivity to selected fungicides showed that all isolates were highly resistant to benomyl (EC50 values were higher than 200.00 mg/l, moderately sensitive to iprodione (EC50 values were between 11.93 and 22.80 mg/l, and highly sensitive to prochloraz-Mn (EC50 values were less than 3.00 mg/l.

  6. 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...

  7. Development of an assay for rapid detection and quantification of Verticillium dahliae in soil.

    Science.gov (United States)

    Bilodeau, Guillaume J; Koike, Steven T; Uribe, Pedro; Martin, Frank N

    2012-03-01

    ABSTRACT Verticillium dahliae is responsible for Verticillium wilt on a wide range of hosts, including strawberry, on which low soil inoculum densities can cause significant crop loss. Determination of inoculum density is currently done by soil plating but this can take 6 to 8 weeks to complete and delay the grower's ability to make planting decisions. To provide a faster means for estimating pathogen populations in the soil, a multiplexed TaqMan real-time polymerase chain reaction (PCR) assay based on the ribosomal DNA (rDNA) intergenic spacer (IGS) was developed for V. dahliae. The assay was specific for V. dahliae and included an internal control for evaluation of inhibition due to the presence of PCR inhibitors in DNA extracted from soil samples. An excellent correlation was observed in regression analysis (R(2) = 0.96) between real-time PCR results and inoculum densities determined by soil plating in a range of field soils with pathogen densities as low as 1 to 2 microsclerotia/g of soil. Variation in copy number of the rDNA was also evaluated among isolates by SYBR Green real-time PCR amplification of the V. dahliae-specific amplicon compared with amplification of several single-copy genes and was estimated to range from ≈24 to 73 copies per haploid genome, which translated into possible differences in results among isolates of ≈1.8 cycle thresholds. Analysis of the variation in results of V. dahliae quantification among extractions of the same soil sample indicated that assaying four replicate DNA extractions for each field sample would provide accurate results. A TaqMan assay also was developed to help identify colonies of V. tricorpus on soil plates.

  8. Evidences for involvement of endogenous cAMP in Arabidopsis defense responses to Verticillium toxins

    Institute of Scientific and Technical Information of China (English)

    Jing JIANG; Ling Wen FAN; Wei Hua WU

    2005-01-01

    Although there were reports suggesting the involvement of endogenous cAMP in plant defense signaling cascades,there is no direct evidence supporting this notion yet and the detailed mechanism is unclear. In the present study, we have used pathogenic fungi Verticillium dahliae and Arabidopsis plants as a model system of plant-microb interaction to demonstrate the function of endogenous cAMP in Arabidopsis defense responses. Both V. dahliae inoculation and Verticillium toxins injection induced typical "wilt" symptoms in Arabidopsis seedlings. When either 8-Br-AMP (a membrane permeable cAMP analogue) or salicylic acid (SA) was applied to Arabidopsis, the plants became resistant to V. dahliae toxins. However, addition of 8-Br-AMP did not increase the resistance of Arabidopsis transgenic plants deficient in SA to the toxins, suggesting that cAMP might act upstream of SA in plant defense signaling pathway.Indeed, 8-Br-cAMP and forskolin, an activator of adenylyl cyclase, significantly stimulated the endogenous SA level in plants, whereas DDA, an inhibitor of adenylyl cyclase dramatically reduced toxin-induced SA increase. Both the endogenous cAMP and SA increased significantly in Arabidopsis seedlings treated with toxins. Furthermore, transcription level of pathogenesis-related protein 1 gene (PR1) was strongly induced by both 8-Br-cAMP and the toxin treatment. Taken together, our data demonstrate that endogenous cAMP is involved in plant defense responses against Verticilliumsecreted toxins by regulating the production of the known signal SA in plant defense pathway.

  9. Development of an assay for rapid detection and quantification of Verticillium dahliae in soil.

    Science.gov (United States)

    Bilodeau, Guillaume J; Koike, Steven T; Uribe, Pedro; Martin, Frank N

    2012-03-01

    ABSTRACT Verticillium dahliae is responsible for Verticillium wilt on a wide range of hosts, including strawberry, on which low soil inoculum densities can cause significant crop loss. Determination of inoculum density is currently done by soil plating but this can take 6 to 8 weeks to complete and delay the grower's ability to make planting decisions. To provide a faster means for estimating pathogen populations in the soil, a multiplexed TaqMan real-time polymerase chain reaction (PCR) assay based on the ribosomal DNA (rDNA) intergenic spacer (IGS) was developed for V. dahliae. The assay was specific for V. dahliae and included an internal control for evaluation of inhibition due to the presence of PCR inhibitors in DNA extracted from soil samples. An excellent correlation was observed in regression analysis (R(2) = 0.96) between real-time PCR results and inoculum densities determined by soil plating in a range of field soils with pathogen densities as low as 1 to 2 microsclerotia/g of soil. Variation in copy number of the rDNA was also evaluated among isolates by SYBR Green real-time PCR amplification of the V. dahliae-specific amplicon compared with amplification of several single-copy genes and was estimated to range from ≈24 to 73 copies per haploid genome, which translated into possible differences in results among isolates of ≈1.8 cycle thresholds. Analysis of the variation in results of V. dahliae quantification among extractions of the same soil sample indicated that assaying four replicate DNA extractions for each field sample would provide accurate results. A TaqMan assay also was developed to help identify colonies of V. tricorpus on soil plates. PMID:22066673

  10. In Vitro and In Vivo Tests for Parasitism of Verticillium psalliotae Treschow on Hemileia Vastatrix BERK. and BR.

    Directory of Open Access Journals (Sweden)

    Mahfud, M. C.

    2006-01-01

    Full Text Available The fungus Verticillium psalliotae Treschow is known to grow on the rust sori masses of Hemileia vastatrix in coffee plantings in Malaysia. However, published reports on this parasite or other biocontrol organisms present naturally in the coffee ecosystems in Malaysia are lacking. In vitro and in vivo studies were conducted to elucidate evidence of parasitism of V. psalliotae on H. vastatrix. The host-mycoparasite interaction conducted in vitro resulted a significant reduction in germination of Hemileia uredespores and an increase in germination of Verticillium conidia. A significant reduction in leaf rust severity by the presence of V. psalliotae, particularly when V. psalliotae was applied 24 hours before the inoculation of H. vastatrix, demonstrated an evidence parasitism in vivo. The evidences were supported by SEM observation of penetration and damage to Hemileia uredospores by hyphae of V. psalliotae.

  11. Identification of miRNAs and Their Targets in Cotton Inoculated with Verticillium dahliae by High-Throughput Sequencing and Degradome Analysis

    Directory of Open Access Journals (Sweden)

    Yujuan Zhang

    2015-06-01

    Full Text Available MicroRNAs (miRNAs are a group of endogenous small non-coding RNAs that play important roles in plant growth, development, and stress response processes. Verticillium wilt is a vascular disease in plants mainly caused by Verticillium dahliae Kleb., the soil-borne fungal pathogen. However, the role of miRNAs in the regulation of Verticillium defense responses is mostly unknown. This study aimed to identify new miRNAs and their potential targets that are involved in the regulation of Verticillium defense responses. Four small RNA libraries and two degradome libraries from mock-infected and infected roots of cotton (both Gossypium hirsutum L. and Gossypium barbadense L. were constructed for deep sequencing. A total of 140 known miRNAs and 58 novel miRNAs were identified. Among the identified miRNAs, many were differentially expressed between libraries. Degradome analysis showed that a total of 83 and 24 genes were the targets of 31 known and 14 novel miRNA families, respectively. Gene Ontology analysis indicated that many of the identified miRNA targets may function in controlling root development and the regulation of Verticillium defense responses in cotton. Our findings provide an overview of potential miRNAs involved in the regulation of Verticillium defense responses in cotton and the interactions between miRNAs and their corresponding targets. The profiling of these miRNAs lays the foundation for further understanding of the function of small RNAs in regulating plant response to fungal infection and Verticillium wilt in particular.

  12. Identification of novel microRNAs in the Verticillium wilt-resistant upland cotton variety KV-1 by high-throughput sequencing.

    Science.gov (United States)

    He, Xiaohong; Sun, Quan; Jiang, Huaizhong; Zhu, Xiaoyan; Mo, Jianchuan; Long, Lu; Xiang, Liuxin; Xie, Yongfang; Shi, Yuzhen; Yuan, Youlu; Cai, Yingfan

    2014-01-01

    Plant microRNAs (miRNAs) play essential roles in the post-transcriptional regulation of gene expression during development, flowering, plant growth, metabolism, and stress responses. Verticillium wilt is one of the vascular disease in plants, which is caused by the Verticillium dahlia and leads to yellowing, wilting, lodging, damage to the vascular tissue, and death in cotton plants. Upland cotton varieties KV-1 have shown resistance to Verticillium wilt in multiple levels. However, the knowledge regarding the post-transcriptional regulation of the resistance is limited. Here two novel small RNA (sRNA) libraries were constructed from the seedlings of upland cotton variety KV-1, which is highly resistant to Verticillium wilts and inoculated with the V991 and D07038 Verticillium dahliae (V. dahliae) of different virulence strains. Thirty-seven novel miRNAs were identified after sequencing these two libraries by the Illumina Solexa system. According to sequence homology analysis, potential target genes of these miRNAs were predicted. With no more than three sequence mismatches between the novel miRNAs and the potential target mRNAs, we predicted 49 target mRNAs for 24 of the novel miRNAs. These target mRNAs corresponded to genes were found to be involved in plant-pathogen interactions, endocytosis, the mitogen-activated protein kinase (MAPK) signaling pathway, and the biosynthesis of isoquinoline alkaloid, terpenoid backbone, primary bile acid and secondary metabolites. Our results showed that some of these miRNAs and their relative gene are involved in resistance to Verticillium wilts. The identification and characterization of miRNAs from upland cotton could help further studies on the miRNA regulatory mechanisms of resistance to Verticillium wilt. PMID:25332864

  13. Expression of baculovirus anti-apoptotic genes p35 and op-iap in cotton (Gossypium hirsutum L. enhances tolerance to verticillium wilt.

    Directory of Open Access Journals (Sweden)

    Juan Tian

    Full Text Available 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 T(3 generation. The transgenic lines had significantly increased tolerance to verticillium wilt throughout the developmental stages. The disease index of T(1-T(3 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.

  14. The rhizosphere effect on bacteria antagonistic towards the pathogenic fungus Verticillium differs depending on plant species and site.

    Science.gov (United States)

    Berg, Gabriele; Opelt, Katja; Zachow, Christin; Lottmann, Jana; Götz, Monika; Costa, Rodrigo; Smalla, Kornelia

    2006-05-01

    Rhizobacteria with antagonistic activity towards plant pathogens play an essential role in root growth and plant health and are influenced by plant species in their abundance and composition. To determine the extent of the effect of the plant species and of the site on the abundance and composition of bacteria with antagonistic activity towards Verticillium dahliae, bacteria isolated from the rhizosphere of two Verticillium host plants, oilseed rape and strawberry, and from bulk soil were analysed at three different locations in Germany over two growing seasons. A total of 6732 bacterial isolates screened for in vitro antagonism towards Verticillium resulted in 560 active isolates, among which Pseudomonas (77%) and Serratia (6%) were the most dominant genera. The rhizosphere effect on the antagonistic bacterial community was shown by an enhanced proportion of antagonistic isolates, by enrichment of specific amplified ribosomal DNA restriction analysis types, species and genotypes, and by a reduced diversity in the rhizosphere in comparison to bulk soil. Such an effect was influenced by the plant species and by the site of its cultivation. Altogether, 16S rRNA gene sequencing of 66 isolates resulted in the identification of 22 different species. Antagonists of the genus Serratia were preferentially isolated from oilseed rape rhizosphere, with the exception of one site. For isolates of Pseudomonas and Serratia, plant-specific and site-specific genotypes were found. PMID:16629754

  15. Molecular Marker-assisted Selection for Verticillium Wilt Resistance in Upland Cotton (Gossypium hirsutum)%陆地棉抗黄萎病性状分子标记辅助选择

    Institute of Scientific and Technical Information of China (English)

    Shui-jin ZHU; Wei-ping FANG; Dao-fan JI

    2002-01-01

    @@ Verticillium wilt is a global important disease of cotton, which threatens the development of cotton production seriously. Recent years,because of the change in climate and cropping pattern, Verticillium wilt was broke out in cotton production areas in China, which became one of the most important factors restricting the continuant development of cotton production.

  16. Island cotton Gbve1 gene encoding a receptor-like protein confers resistance to both defoliating and non-defoliating isolates of Verticillium dahliae.

    Directory of Open Access Journals (Sweden)

    Baolong Zhang

    Full Text Available Verticillium wilt caused by soilborne fungus Verticillium dahliae could significantly reduce cotton yield. Here, we cloned a tomato Ve homologous gene, Gbve1, from an island cotton cultivar that is resistant to Verticillium wilt. We found that the Gbve1 gene was induced by V. dahliae and by phytohormones salicylic acid, jasmonic acid, and ethylene, but not by abscisic acid. The induction of Gbve1 in resistant cotton was quicker and stronger than in Verticillium-susceptible upland cotton following V. dahliae inoculation. Gbve1 promoter-driving GUS activity was found exclusively in the vascular bundles of roots and stems of transgenic Arabidopsis. Virus-induced silencing of endogenous genes in resistant cotton via targeting a fragment of the Gbve1 gene compromised cotton resistance to V. dahliae. Furthermore, we transformed the Gbve1 gene into Arabidopsis and upland cotton through Agrobacterium-mediated transformation. Overexpression of the Gbve1 gene endowed transgenic Arabidopsis and upland cotton with resistance to high aggressive defoliating and non-defoliating isolates of V. dahliae. And HR-mimic cell death was observed in the transgenic Arabidopsis. Our results demonstrate that the Gbve1 gene is responsible for resistance to V. dahliae in island cotton and can be used for breeding cotton varieties that are resistant to Verticillium wilt.

  17. 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

  18. QTL Analysis of Fiber Yield and Quality and Resistance to Verticillium Wilt Using Gossypium hirsutum and G.barbadense Advanced Backcross Populations

    Institute of Scientific and Technical Information of China (English)

    LI Ai-guo; WANG Tao; YUAN You-lu; LIU Guang-ping; ZHANG Bao-cai; LI Jun-wen; SHI Yu-zhen; LIU Ai-ying; YANG Ze-mao; LIU Zhi; YU Xiao-nan

    2008-01-01

    @@ To introgress elite QTL alleles of Gossypium barbadense L.for fiber yield and quality and resistance to Verticillium wilt into G.hirsutum L.,enlarge the genetic base of G.hirsutum,and provide new germplasm resources for the variety development,the cultivars Zhongmiansuo 36,G.hirsutum,and Hai 1,G.barbadense,were used as recurrent and donor parent,respectively,to produce BC1 F1,BC1S1,and BC2F1 populations.QTL analyses of fiber quality,yield-related,Key words: interspecific backcrosss; AB-QTL; fiber quality; yield; Verticillium wilt resistance

  19. Development of modified medium for the enhancement in antifungal activity of P. steckii (MF1 mangrove fungi against verticillium wilt pathogenic fungi of rose

    Directory of Open Access Journals (Sweden)

    Jyotasanmayee Sabat

    2009-08-01

    Full Text Available The antifungal activity of Penicillium steckii (MF1 against pathogenic fungi of rose causing verticillium wilt was evaluated under differential nutrient condition. A suitable and modified medium was obtained in which test fungus exhibited enhanced antifungal activity and produced larger inhibition zone against the verticillium fungus. The study carried out to modify the medium components at level of nitrogen, carbon source and their concentration on agar plates. Addition of amino acids, metals and plant growth hormones did not show positive effect but glycerol enhanced the antifungal activity very much.

  20. 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. PMID:25074353

  1. 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.

  2. Evaluation of Fungicides on Growth and Conidial Germination of Verticillium theobromae Isolated from Plantain

    Science.gov (United States)

    Igeleke, C. L.; Ayanru, D. K. G.

    An evaluation of three fungicides, namely, benomyl [methyl l-(butyl-carbamoyl)-2-benzimidazole carbamate], calixin (tridomorph) and dithane M-45 (mancozeb), was carried out for their inhibitory effects on Verticillium theobromae, the causal organism of cigar-end rot disease of plantain (Musa paradisiaca). The LD50 of calixin, benomyl and dithane M-45 in inhibiting mycelial growth, were 0.14, 0.98 and 535.17 µg mL-1, respectively. Calixin was also the most effective in conidial germination inhibition with an LD50 of 21.78 µg mL-1, as compared with dithane M-45 86.39 µg mL-1 and benomyl 275.50 µg mL-1. Germ tubes of the test organism were distorted by the fungicides at varying concentrations. Calixin had greater distortion effect at a lower concentration of 10 µg mL-1, dithane M-45 (100 µg mL-1) and benomyl (1000 µg mL-1). The relevance of these results in relation to the control and management of cigar-end rot disease of plantain is discussed.

  3. Identification and characterization of a pathogenicity-related gene VdCYP1 from Verticillium dahliae.

    Science.gov (United States)

    Zhang, Dan-Dan; Wang, Xin-Yan; Chen, Jie-Yin; Kong, Zhi-Qiang; Gui, Yue-Jing; Li, Nan-Yang; Bao, Yu-Ming; Dai, Xiao-Feng

    2016-01-01

    Verticillium dahliae is a phytopathogenic fungus that causes vascular wilt disease in a wide variety of crop plants, thereby causing extensive economic loss. In present study, one V. dahliae T-DNA mutant M01C06 showed the pathogenicity loss on cotton, and the expression of a flanking gene encoding cytochrome P450 monooxygenase (P450, VdCYP1) was strongly repressed. P450s of fungi could affect the fungal pathogenicity by involving in the synthesis of secondary metabolites. However, there was no report about the pathogenic function of P450s in V. dahliae. VdCYP1 gene deletion and complementation experiments confirmed that VdCYP1 was the pathogenicity-related gene in V. dahliae. A comparison of culture supernatants of the VdCYP1 deletion mutants and wild-type strains indicates that at least 14 kinds of secondary metabolites syntheses were affected due to VdCYP1 gene deletion. One of these compounds, sulfacetamide, had the ability to induce the necrosis and wilting symptoms in cotton. Above results indicate that VdCYP1 could participate in pathogenesis by involving the secondary metabolism in V. dahliae, such as the compound sulfacetamide. In conclusion, VdCYP1 acts as an important pathogenicity-related factor to involve in secondary metabolism that likely contributes to the pathogenic process in V. dahliae. PMID:27329129

  4. Verticillium dahliae alters Pseudomonas spp. populations and HCN gene expression in the rhizosphere of strawberry.

    Science.gov (United States)

    DeCoste, Nadine J; Gadkar, Vijay J; Filion, Martin

    2010-11-01

    The production of hydrogen cyanide (HCN) by beneficial root-associated bacteria is an important mechanism for the biological control of plant pathogens. However, little is known about the biotic factors affecting HCN gene expression in the rhizosphere of plants. In this study, real-time reverse transcription PCR (qRT-PCR) assays were developed to investigate the effect of the plant pathogen Verticillium dahliae on hcnC (encoding for HCN biosynthesis) gene expression in Pseudomonas sp. LBUM300. Strawberry plants were inoculated with Pseudomonas sp. LBUM300 and (or) V. dahliae and grown in pots filled with nonsterilized field soil. RNA was extracted from rhizosphere soil sampled at 0, 15, 30, and 45 days following inoculation with V. dahliae and used for qRT-PCR analyses. Populations of V. dahliae and Pseudomonas sp. LBUM300 were also monitored using a culture-independent qPCR approach. hcnC expression was detected at all sampling dates. The presence of V. dahliae had a significant stimulation effect on hcnC gene expression and also increased the population of Pseudomonas sp. LBUM300. However, the V. dahliae population was not altered by the presence of Pseudomonas sp. LBUM300. To our knowledge, this study is the first to evaluate the effect of a plant pathogen on HCN gene expression in the rhizosphere soil. PMID:21076481

  5. Identification and characterization of a pathogenicity-related gene VdCYP1 from Verticillium dahliae

    Science.gov (United States)

    Zhang, Dan-Dan; Wang, Xin-Yan; Chen, Jie-Yin; Kong, Zhi-Qiang; Gui, Yue-Jing; Li, Nan-Yang; Bao, Yu-Ming; Dai, Xiao-Feng

    2016-01-01

    Verticillium dahliae is a phytopathogenic fungus that causes vascular wilt disease in a wide variety of crop plants, thereby causing extensive economic loss. In present study, one V. dahliae T-DNA mutant M01C06 showed the pathogenicity loss on cotton, and the expression of a flanking gene encoding cytochrome P450 monooxygenase (P450, VdCYP1) was strongly repressed. P450s of fungi could affect the fungal pathogenicity by involving in the synthesis of secondary metabolites. However, there was no report about the pathogenic function of P450s in V. dahliae. VdCYP1 gene deletion and complementation experiments confirmed that VdCYP1 was the pathogenicity-related gene in V. dahliae. A comparison of culture supernatants of the VdCYP1 deletion mutants and wild-type strains indicates that at least 14 kinds of secondary metabolites syntheses were affected due to VdCYP1 gene deletion. One of these compounds, sulfacetamide, had the ability to induce the necrosis and wilting symptoms in cotton. Above results indicate that VdCYP1 could participate in pathogenesis by involving the secondary metabolism in V. dahliae, such as the compound sulfacetamide. In conclusion, VdCYP1 acts as an important pathogenicity-related factor to involve in secondary metabolism that likely contributes to the pathogenic process in V. dahliae. PMID:27329129

  6. Investigating Agrobacterium-mediated transformation of Verticillium albo-atrum on plant surfaces.

    Directory of Open Access Journals (Sweden)

    Claire J Knight

    Full Text Available BACKGROUND: Agrobacterium tumefaciens has long been known to transform plant tissue in nature as part of its infection process. This natural mechanism has been utilised over the last few decades in laboratories world wide to genetically manipulate many species of plants. More recently this technology has been successfully applied to non-plant organisms in the laboratory, including fungi, where the plant wound hormone acetosyringone, an inducer of transformation, is supplied exogenously. In the natural environment it is possible that Agrobacterium and fungi may encounter each other at plant wound sites, where acetosyringone would be present, raising the possibility of natural gene transfer from bacterium to fungus. METHODOLOGY/PRINCIPAL FINDINGS: We investigate this hypothesis through the development of experiments designed to replicate such a situation at a plant wound site. A. tumefaciens harbouring the plasmid pCAMDsRed was co-cultivated with the common plant pathogenic fungus Verticillium albo-atrum on a range of wounded plant tissues. Fungal transformants were obtained from co-cultivation on a range of plant tissue types, demonstrating that plant tissue provides sufficient vir gene inducers to allow A. tumefaciens to transform fungi in planta. CONCLUSIONS/SIGNIFICANCE: This work raises interesting questions about whether A. tumefaciens may be able to transform organisms other than plants in nature, or indeed should be considered during GM risk assessments, with further investigations required to determine whether this phenomenon has already occurred in nature.

  7. Allelopathic effects of the root exudates of grafted eggplants on the verticillium wilt, Verticillium dahliae%嫁接茄子根系分泌物对黄萎病菌的化感作用

    Institute of Scientific and Technical Information of China (English)

    廉华; 王茹华

    2009-01-01

    研究了不同砧木、不同浓度嫁接茄子根系分泌物对茄子黄萎病菌(Verticillium dahliae)孢子萌发和菌丝生长的影响.结果表明,与自根茄相比,所有参试的嫁接茄根系分泌物都不同程度抑制了黄萎病菌孢子萌发和菌丝生长;并且随着根系分泌物浓度的增加,抑制作用增强.

  8. Identification of causal agent for sunflower Verticillium wilt%向日葵黄萎病病原鉴定

    Institute of Scientific and Technical Information of China (English)

    裴旭; 杨柳青; 徐鑫; 景岚

    2012-01-01

    从黑龙江、内蒙古东部和西部、河北、陕西、宁夏、新疆向日葵黄萎病发生严重的地块采集有典型症状的200多个病株进行病原物分离,通过常规组织分离法分离到120个菌株.在PDA培养基上,其菌落表现黑色、白色及灰白色.显微镜下观察其营养菌丝透明、有分隔,呈轮状分枝;分生孢子卵圆或椭圆形、单细胞;大多产生黑色微菌核.提取DNA并进行ITS序列分析(ITS1/ITS4),证实该120个向日葵黄萎病菌株均为轮枝孢属大丽轮枝菌(Verticillium dahliae Kleb.).%More than 200 diseased plants having shown typical Verticillium wilt symptoms were collected from Heilongjiang, Inner Mongolia Autonomous Region, Hebei, Shanxi, Shaanxi, Ningxia Hui Autonomous Region and the Xinjiang Uygur Autonomous Region. 120 strains obtained by tissue isolation technics were identified. On PDA, the colonies showed black, white or gray white. The vegetative mycelium was hyaline and septate. Conidia were o-void or ellipsoid and single - celled. They were borne on phialides, which were produced in a whorl around each conidiophore. Most of these isolates produced black microsclerotia. Genomic DNA was extracted and used as a template for amplification of the internal transcribed spacer (ITS) region of rDNA with primer pair ITS1/ITS4. All of the 120 strains were identified as Verticillium dahliae Kleb.

  9. Molecular mapping of Verticillium wilt resistance QTL clustered on chromosomes D7 and D9 in upland cotton

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Verticillium wilt is a destructive disease with international consequences for cotton production. Breeding broad-spectrum resistant cultivars is considered to be one of the most effective means for reducing crop losses. A resistant cotton cultivar,60182,was crossed with a susceptible cultivar,Jun-mian 1,to identify markers for Verticillium resistance genes and validate the mode of its inheritance. Genetic segregation analysis for Verticillium wilt resistance was evaluated based upon infected leaf percentage in the seedling stage using major gene-polygene mixed inheritance models and joint analysis of P1,P2,F1,B1,B2 and F2 populations obtained from the cultivar cross. We found that resistance of upland cotton cultivar 60182 to isolates BP2,VD8 and T9,and their isoconcentration mixture was controlled by two major genes with additive-dominance-epistatic effects,and the inheritance of the major gene was dominant. Furthermore,a genetic linkage map was constructed using F2 segregating population and resistance phenotypic data were obtained using F2:3 families inoculated with different isolates and detected in different developmental stages. The genetic linkage map with 139 loci was comprised of 31 linkage groups covering 1165 cM,with an average distance of 8.38 cM between two markers,or 25.89% of the cotton genome length. From 60182,we found 4 QTL on chromosome D7 and 4 QTL on D9 for BP2,5 QTL on D7 and 9 QTL on D9 for VD8,4 QTL on D7 and 5 QTL on D9 for T9 and 3 QTL on D7 and 7 QTL on D7 for mixed pathogens. The QTL mapping results revealed that QTL clusters with high contribution rates were screened simultaneously on chromosomes D9 and D7 by multiple interval mapping (CIM),whether from resistance phenotypic data from different developmental stages or for different isolates. The result is consistent with the genetic model of two major genes in 60182 and suggests broad-spectrum resistance to both defoliating isolates of V. dahliae and nondefoliating isolates. The markers

  10. Advances in the Study of Cotton Resistance Verticillium Wilt%棉花抗黄萎病研究进展

    Institute of Scientific and Technical Information of China (English)

    石海燕; 张玉星

    2010-01-01

    棉花黄萎病是一种由黄萎病菌(Verticillium dahliae)引起的在全世界蔓延的真菌病害.介绍了棉花黄萎病的致病机理、棉花对黄萎病的抗性机理及棉花抗黄萎病转基因育种的研究进展,可为抗棉花黄萎病的研究工作提供一定的思路.

  11. Growth, yield and physiology of Verticillium-inoculated pepper plants treated with ATAD and composted sewage sludge

    OpenAIRE

    Pascual, I. (I.); Azcona, I.; Morales, F.; Aguirreolea, J.; Sanchez-Diaz, M. (Manuel)

    2009-01-01

    A greenhouse experiment was conducted to investigate the impact of sanitized sewage sludges, ATAD (aerobic thermophilic autothermic digestion) and composted, on Verticillium-induced wilt in pepper plants (Capsicum annuum L. cv. Piquillo). Two doses of ATAD (15 and 30% v/v) and three of composted sludge (15, 30 and 45% v/v) were applied to a peat-based potting mix. Unamended substrate was included as control. Half of the plants were inoculated with V. dahliae, whereas the other half remained n...

  12. Results from a three year testing project of new strawberry cultivars in Verticillium infested soils and under organic farming conditions

    OpenAIRE

    Spornberger, A.; Weissinger, H.; Steffek, R.; Scheiblauer, J.; Jezik, K.; Altenburger, J.; Stich, K.

    2008-01-01

    As part of a research project 13 cultivars were planted in 2005 at 11 sites on 9 farms in 5 different Austrian regions. The aim was to find new cultivars tolerant to soil-borne pathogens and leaf/fruit diseases, with high yield, winter hardness and good fruit quality, to serve as alternative to the highly susceptible cultivar ‘Elsanta’, regarding soil-borne diseases. Plant vigour and infestation with Verticillium dahliae and leaf diseases were evaluated in 2005 und 2006 at 7 si...

  13. Photonic Crystal Fiber Attenuator

    Institute of Scientific and Technical Information of China (English)

    Joo Beom Eom; Hokyung Kim; Jinchae Kim; Un-Chul Paek; Byeong Ha Lee

    2003-01-01

    We propose a novel fiber attenuator based on photonic crystal fibers. The difference in the modal field diameters of a conventional single mode fiber and a photonic crystal fiber was used. A variable optical attenuator was also achieved by applying macro-bending on the PCF part of the proposed attenuator

  14. The mitogen-activated protein kinase gene, VdHog1, regulates osmotic stress response, microsclerotia formation and virulence in Verticillium dahliae

    Science.gov (United States)

    The fungus Verticillium dahliae has gained worldwide notoriety as a destructive plant pathogen, causing vascular wilt diseases on diverse plant species. The fungus produces melanized resting bodies, known as microsclerotia that can survive for 15 years in the soil, and are thus critically important ...

  15. Identification of quantitative trait loci for resistance to Verticillium wilt and yield parameters in hop (Humulus lupulus L.).

    Science.gov (United States)

    Jakse, Jernej; Cerenak, Andreja; Radisek, Sebastjan; Satovic, Zlatko; Luthar, Zlata; Javornik, Branka

    2013-06-01

    Verticillium wilt (VW) can cause substantial yield loss in hop particularly with the outbreaks of the lethal strain of Verticillium albo-atrum. To elucidate genetic control of VW resistance in hop, an F1 mapping population derived from a cross of cultivar Wye Target, with the predicted genetic basis of resistance, and susceptible male breeding line BL2/1 was developed to assess wilting symptoms and to perform QTL mapping. The genetic linkage map, constructed with 203 markers of various types using a pseudo-testcross strategy, formed ten major linkage groups (LG) of the maternal and paternal maps, covering 552.98 and 441.1 cM, respectively. A significant QTL for VW resistance was detected at LOD 7 on a single chromosomal region on LG03 of both parental maps, accounting for 24.2-26.0 % of the phenotypic variance. QTL analysis for alpha-acid content and yield parameters was also performed on this map. QTLs for these traits were also detected and confirmed our previously detected QTLs in a different pedigree and environment. The work provides the basis for exploration of QTL flanking markers for possible use in marker-assisted selection. PMID:23423654

  16. Verticase:a Fibrinolytic Enzyme Produced by Verticillium sp.Tj33,an Endophyte of Trachelospermum jasminoides

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Plant endophytes are among the most important resources of biologically active metabolites.Twenty-three endophyte strains residing in Trachelospermum jasminoides were cultivated In with the cultures assayed for the fibrinolytic substance production.As a result,the culture of Verticillium sp.Tj33 was shown to be the most active.A fibrinolytic enzyme designated as verticase was subsequently purified from the supernatant of Verticillium sp.culture broth by a combination of DEAE-52,Sephadex G-75 and hydrophobic column chromatographies.Verticase,with its molecular mass of 31 kDa and pl of 8.5,was demonstrated to be homogeneous by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and isoelectric focusing electrophoresis.Verticase is an enzyme that hydrolyzes fibrin directly without activation of plaminogen.It was stable in a broad pH range from 4 through to 11 with the optimal reaction pH value and temperature shown to be around 9-10 and 50-60℃,respectively.The fibrinolytic activity of verticase was severely inhibited by phenylmethylsulfony fluoride,Indicating that verticase was a serine protease.

  17. 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.

  18. Variable laser attenuator

    Science.gov (United States)

    Foltyn, Stephen R.

    1988-01-01

    The disclosure relates to low loss, high power variable attenuators comprng one or more transmissive and/or reflective multilayer dielectric filters. The attenuator is particularly suitable to use with unpolarized lasers such as excimer lasers. Beam attenuation is a function of beam polarization and the angle of incidence between the beam and the filter and is controlled by adjusting the angle of incidence the beam makes to the filter or filters. Filters are selected in accordance with beam wavelength.

  19. 桃树黄萎病在我国首次发生报道%The first report of peach trees verticillium wilt caused by Verticillium dahliae in China

    Institute of Scientific and Technical Information of China (English)

    何苏琴; 荆卓琼; 白滨; 文朝慧; 陈建军

    2015-01-01

    在甘肃省农业科学院林果所2010年建植的桃园内,自2011年以来,每年6-8月都陆续出现枯兀的桃树;严重年份桃树病株率达20%.经病原菌分离培养、形态观察和致病性测定,确认桃树枯死是由大丽轮枝菌(Verticillium dahliae)侵染所致.这是桃树黄萎病在我国的首次发生报道.

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

    Directory of Open Access Journals (Sweden)

    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.

  1. [Relationship of Sa, No and H2O2 signals in the reponses of Arabidopsis to toxin of Verticillium dahliae].

    Science.gov (United States)

    Li, Shuang Shi; Li, Ying Zhang

    2004-08-01

    The accumulation of hydrogen peroxide (H2O2) in Arabidopsis was induced by toxin of Verticillium dahliae (VD-toxin), exogenous salicylic acid (SA) and nitric oxide donor (SNP). The effect of SNP was the most intense. H2O2 level was not increased in Arabidopsis treated with nitric oxide synthase inhibitor (NNA). It was identified with the results of DAB staining of H2O2 accumulates in the leaves of Arabidopsis. H2O2 was cytochemically detected in the cells of epidermal hair and the cell wall of vascular parenchyma cell. The results suggest that H2O2 acts as a second messenger to involve the defenses in Arabidopsis induced by SA and NO signal transduction. The relationship of NO and H2O2 signals was likely closer.

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

    Science.gov (United States)

    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 suggest that VdMcm1 is involved in cell wall integrity. Finally, comparative RNA-Seq analysis reveals 823 significantly downregulated genes in the VdMcm1 deletion mutant, with diverse biological functions in transcriptional regulation, plant infection, cell adhesion, secondary metabolism, transmembrane transport activity, and cell secretion. When taken together, these data suggest that VdMcm1 performs pleiotropic functions in V. dahliae. PMID:27536281

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

    Science.gov (United States)

    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 suggest that VdMcm1 is involved in cell wall integrity. Finally, comparative RNA-Seq analysis reveals 823 significantly downregulated genes in the VdMcm1 deletion mutant, with diverse biological functions in transcriptional regulation, plant infection, cell adhesion, secondary metabolism, transmembrane transport activity, and cell secretion. When taken together, these data suggest that VdMcm1 performs pleiotropic functions in V. dahliae. PMID:27536281

  4. A synthetic antimicrobial peptide BTD-S expressed in Arabidopsis thaliana confers enhanced resistance to Verticillium dahliae.

    Science.gov (United States)

    Li, Feng; Shen, Hao; Wang, Ming; Fan, Kai; Bibi, Noreen; Ni, Mi; Yuan, Shuna; Wang, Xuede

    2016-08-01

    BTD-S is a synthetic non-cyclic θ-defensin derivative which was previously designed in our laboratory based on baboon θ-defensins (BTDs). It shows robust antimicrobial activity against economically important phytopathogen, Verticillium dahliae. Here, we deduced the coding nucleotide sequence of BTD-S and introduced the gene into wild-type (ecotype Columbia-0) Arabidopsis thaliana plants. Results demonstrated that BTD-S-transgenic lines displayed in bioassays inhibitory effects on the growth of V. dahliae in vivo and in vitro. Based on symptom severity, enhanced resistance was found in a survey of BTD-S-transgenic lines. Besides, crude protein extracts from root tissues of BTD-S-transformed plants significantly restricted the growth of fungal hyphae and the germination of conidia. Also, fungal biomass over time determined by real-time PCR demonstrated the overgrowth of V. dahliae in wild-type plants 2-3 weeks after inoculation, while almost no fungal DNA was detected in aerial tissues of their transgenic progenitors. The result suggested that fungus failed to invade and progress acropetally up to establish a systemic infection in BTD-S-transgenic plants. Moreover, the assessment of basal defense responses was performed in the leaves of WT and BTD-S-transgenic plants. The mitigated oxidative stress and low antioxidase level in BTD-S-transgenic plants revealed that BTD-S acts via permeabilizing target microbial membranes, which is in a category different from hypersensitive response-dependent defense. Taken together, our results demonstrate that BTD-S is a promising gene to be explored for transgenic engineering for plant protection against Verticillium wilt.

  5. 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.

  6. 棉花黄萎病菌致病的分子机理%The Molecular Mechanism of Pathogenicity for Verticillium dahliae Kleb

    Institute of Scientific and Technical Information of China (English)

    汪敏; 焦睿; 邢小萍; 房卫平; 李洪连

    2011-01-01

    In this review, we elucidated the role of cell-wall-degrading enzymes, proteases, phytotoxins produced by Verticillium dahliae Kleb in pathogenicity and the mechanism of microsclerotial development. Recent advances in fungi functional genomics technologies such as genomics methods, RNA interference (RNAi) and Agrobacterium trmefaciens-mediated transformation (ATMT)applied for researching on the pathogenisis molecular mechanism of V. dahliae were also reviewed.%阐述了大丽轮枝菌(Verticillium dahliae Kleb)产生的细胞壁降解酶、蛋白酶和毒素在致病中的作用及微菌核形成机制,全面分析了基因组学途径、RNA干涉和农杆菌介导的转化等真菌功能基因组学技术在大丽轮枝菌致病分子机理研究上的进展.

  7. Conclusion on the peer review of the pesticide risk assessment of the active substance Verticillium albo-atrum (strain WCS850

    Directory of Open Access Journals (Sweden)

    European Food Safety Authority

    2013-01-01

    Full Text Available The conclusions of the European Food Safety Authority (EFSA following the peer review of the initial risk assessments carried out by the competent authority of the rapporteur Member State, The Netherlands, for the pesticide active substance Verticillium albo-atrum (strain WCS850 are reported. The context of the peer review was that required by Commission Regulation (EC No 2229/2004, as amended by Commission Regulation (EC No 1095/2007. The conclusions were reached on the basis of the evaluation of the representative use of Verticillium albo-atrum as an elicitor of the elm tree’s self-defence mechanism against Dutch elm disease. The reliable endpoints concluded as being appropriate for use in regulatory risk assessment, derived from the available studies and literature in the dossier peer reviewed, are presented.

  8. Dysfunctionality of the xylem in Olea europaea L. Plants associated with the infection process by Verticillium dahliae Kleb. Role of phenolic compounds in plant defense mechanism.

    Science.gov (United States)

    Báidez, Ana G; Gómez, Pedro; Del Río, José A; Ortuño, Ana

    2007-05-01

    Xylem ultrastructural modification and the possible participation of phenolic compounds in the natural defense or resistance mechanisms of olive plants infected with Verticillium dahliae Kleb. were studied. Microscopic study showed that the mycelium propagated and passed from one element to another through the pit. The formation of tyloses and aggregates contributed to obstruction of the xylem lumen. In vivo changes in the levels of these phenolic compounds in infected olive plants and their antifungal activity against Verticillium dahliae Kleb., as revealed by in vitro study, strongly suggest that they are involved in natural defense or resistance mechanisms in this plant material, the most active being quercetin and luteolin aglycons, followed by rutin, oleuropein, luteolin-7-glucoside, tyrosol, p-coumaric acid, and catechin. . PMID:17394331

  9. Influence of Soil Type, Cultivar and Verticillium dahliae on the Structure of the Root and Rhizosphere Soil Fungal Microbiome of Strawberry

    OpenAIRE

    Srivathsa Nallanchakravarthula; Shahid Mahmood; Sadhna Alström; 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 communi...

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

    OpenAIRE

    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 (i.e. short melanised hyphae attached to the microsclerotia) and dark mycelium (i.e. melanised mycelium throughout the colony). On modified soil extract agar (MSEA), a pectate based agar, V. dahliae ...

  11. 几种药剂防治棉花黄萎病试验初报%Preliminary Experiment of Several Pesticides against Verticillium Dahliae Kleb

    Institute of Scientific and Technical Information of China (English)

    何宝威; 曹维山

    2010-01-01

    采用5种杀菌剂对棉花黄萎病(Verticillium dahliae Kleb)进行防治试验.试验结果表明,天达2116对棉花黄萎病防治效果最好,防效达到85.66%,在棉花黄萎病的防治中将具有重要的价值.

  12. Transcriptional Activation and Production of Tryptophan-Derived Secondary Metabolites in Arabidopsis Roots Contributes to the Defense against the Fungal Vascular Pathogen Verticillium Iongisporum

    Institute of Scientific and Technical Information of China (English)

    Tim Iven; Wolfgang Dr(o)ge-Laser; Stefanie K(o)nig; Seema Singh; Susanna A.Braus-Stromeyer; Matthias Bischoff; Lutz F.Tietze; Gerhard H.Braus; Volker Lipka; Ivo Feussner

    2012-01-01

    The soil-borne fungal pathogen Verticillium Iongisporum causes vascular disease on Brassicaceae host plants such as oilseed rape.The fungus colonizes the root xylem and moves upwards to the foliage where disease symptoms become visible.Using Arabidopsis as a model for early gene induction,we performed root transcriptome analyses in response to hyphal growth immediately after spore germination and during penetration of the root cortex,respectively.Infected roots showed a rapid reprogramming of gene expression such as activation of transcription factors,stress-,and defense-related genes.Here,we focused on the highly coordinated gene induction resulting in the production of tryptophan-derived secondary metabolites.Previous studies in leaves showed that enzymes encoded by CYP81F2 and PEN2 (PENETRATION2) execute the formation of antifungal indole glucosinolate (IGS) metabolites.In Verticillium-infected roots.we found transcriptional activation of CYP81F2 and the PEN2 homolog PEL1 (PEN2-LIKE1),but no increase in antifungal IGS breakdown products.In contrast,indole-3-carboxylic acid (I3CA) and the phytoalexin camalexin accumulated in infected roots but only camalexin inhibited Verticillium growth in vitro.Whereas genetic disruption of the individual metabolic pathways leading to either camalexin or CYP81F2-dependent IGS metabolites did not alter Verticillium-induced disease symptoms,a cyp79b2 cyp79b3 mutant impaired in both branches resulted in significantly enhanced susceptibility.Hence,our data provide an insight into root-specific early defenses and suggest tryptophan-derived metabolites as active antifungal compounds against a vascular pathogen.

  13. 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

  14. 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

  15. Planetary Ices Attenuation Properties

    Science.gov (United States)

    McCarthy, Christine; Castillo-Rogez, Julie C.

    In this chapter, we review the topic of energy dissipation in the context of icy satellites experiencing tidal forcing. We describe the physics of mechanical dissipation, also known as attenuation, in polycrystalline ice and discuss the history of laboratory methods used to measure and understand it. Because many factors - such as microstructure, composition and defect state - can influence rheological behavior, we review what is known about the mechanisms responsible for attenuation in ice and what can be inferred from the properties of rocks, metals and ceramics. Since attenuation measured in the laboratory must be carefully scaled to geologic time and to planetary conditions in order to provide realistic extrapolation, we discuss various mechanical models that have been used, with varying degrees of success, to describe attenuation as a function of forcing frequency and temperature. We review the literature in which these models have been used to describe dissipation in the moons of Jupiter and Saturn. Finally, we address gaps in our present knowledge of planetary ice attenuation and provide suggestions for future inquiry.

  16. 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.

  17. Frequency Dependent Attenuation Revisited

    CERN Document Server

    Richard, Kowar; Xavier, Bonnefond

    2009-01-01

    The work is inspired by thermo-and photoacoustic imaging, where recent efforts are devoted to take into account attenuation and varying wave speed parameters. In this paper we study causal equations describing propagation of attenuated pressure waves. We review standard models like frequency power laws and and the thermo-viscous equation. The lack of causality of standard models in the parameter range relevant for photoacoustic imaging requires to derive novel equations. The main ingredients for deriving causal equations are the Kramers-Kronig relation and the mathematical concept of linear system theory. The theoretical results of this work are underpined by numerical experiments.

  18. 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

  19. Preliminary Study on Screening and Antagonistic Mechanism of Indicator Microbe for Wilting Toxin from Verticillium dahliae%大丽轮枝菌致萎毒力指示菌的筛选及拮抗作用初探

    Institute of Scientific and Technical Information of China (English)

    王世英; 姜军坡; 李术娜; 朱宝成; 薛庆林

    2010-01-01

    为了筛选可指示Verticillium dahliae致萎毒素毒力大小的指示菌.并对致萎毒素抑制指示菌生长的机理进行初步探讨,采用指示菌平板打孔法,对黑曲霉(Aspergillus niger)BF-3758、枯草芽孢杆菌(Bacillus subtilis)、金黄色葡萄球(Staphylococcus aurcus)、啤酒酵母(Saccharomyces cerevisiae)等12种具有微生物种属代表性的菌株进行筛选:采用拮抗试验、致萎试验结合显微观察的方法,初步探索了Verticillium dahliae致萎毒素对指示菌生长的抑制作用.结果表明,Verticillium dahliae粗毒素对Aspergillus niger BF-3758的生长具有较强的抑制作用,且该抑制作用和粗毒素对离体叶片的致萎作用具有一致性,并存在一定的量效关系,Aspergillus niger BF-3758菌株可以作为Verticillium dahliae致萎毒素的毒力指示菌;Verticillium dahliae粗毒素可抑制Aspergillus niger BF-3758的孢子萌发和菌丝生长,对成熟菌丝也有破坏作用.上述研究可为评价Verticillium dahliae的致病力提供一种操作简便、耗时短、费用低的生物学方法.

  20. Trichoderma Harzianum’un pamuklarda çökerten ( Rhizoctonia Solani Kühn.) ve verticillium solgunluğu hastalığı (Verticillium Dahliae Kleb.)’na etkisinin in-vivo koşullarda saptanması

    OpenAIRE

    Yıldız, Ayhan; Benlioğlu, Seher

    2009-01-01

    Çalışma, Trichoderma harzianum Kuen 1585’u içeren mikrobiyal gübrenin, pamukta Verticillium Solgunluğu Hastalığı etmeni Verticillium dahliae ile pamukta çökerten etmeni Rhizoctonia solani’ye ve pamuk fidesinin gelişimine etkisini in-vivo koşullarda tespit etmek amacıyla ele alınmıştır. Denemede virülensi yüksek iki V. dahliae izolatı (5/3 ve 20/2) kullanılmış ve izolatlar gövdeye enjeksiyon yöntemi ile 4- 6 gerçek yapraklı dönemdeki Acala SJ-2 çeşidine ait pamuk bitkilerine uygula...

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

    Directory of Open Access Journals (Sweden)

    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.

  2. Isolation and functional analysis of the pathogenicity-related gene VdPR3 from Verticillium dahliae on cotton.

    Science.gov (United States)

    Zhang, Ya-Lin; Li, Zhi-Fang; Feng, Zi-Li; Feng, Hong-Jie; Zhao, Li-Hong; Shi, Yong-Qiang; Hu, Xiao-Ping; Zhu, He-Qin

    2015-11-01

    The fungal plant pathogen Verticillium dahliae is the causal agent of vascular wilt, a disease that can seriously diminish cotton fiber yield. The pathogenicity mechanism and the identity of the genes that interact with cotton during the infection process still remain unclear. In this study, we investigated the low-pathogenic, non-microsclerotium-producing mutant vdpr3 obtained in a previous study from the screening of a T-DNA insertional library of the highly virulent isolate Vd080; the pathogenicity-related gene (VdPR3) in wild-type strain Vd080 was cloned. Knockout mutants (ΔVdPR3) showed lower mycelium growth and obvious reduction in sporulation ability without microsclerotium formation. An evaluation of carbon utilization in mutants and wild-type isolate Vd080 demonstrated that mutants-lacking VdPR3 exhibited decreased cellulase and amylase activities, which was restored in the complementary mutants (ΔVdPR3-C) to levels similar to those of Vd080. ΔVdPR3 postponed infectious events in cotton and showed a significant reduction in pathogenicity. Reintroduction of a functional VdPR3 copy into ΔVdPR3-C restored the ability to infect cotton plants. These results suggest that VdPR3 is a multifunctional gene involved in growth development, extracellular enzyme activity, and virulence of V. dahliae on cotton. PMID:25652159

  3. Discovery and identification of candidate genes from the chitinase gene family for Verticillium dahliae resistance in cotton

    Science.gov (United States)

    Xu, Jun; Xu, Xiaoyang; Tian, Liangliang; Wang, Guilin; Zhang, Xueying; Wang, Xinyu; Guo, Wangzhen

    2016-01-01

    Verticillium dahliae, a destructive and soil-borne fungal pathogen, causes massive losses in cotton yields. However, the resistance mechanism to V. dahilae in cotton is still poorly understood. Accumulating evidence indicates that chitinases are crucial hydrolytic enzymes, which attack fungal pathogens by catalyzing the fungal cell wall degradation. As a large gene family, to date, the chitinase genes (Chis) have not been systematically analyzed and effectively utilized in cotton. Here, we identified 47, 49, 92, and 116 Chis from four sequenced cotton species, diploid Gossypium raimondii (D5), G. arboreum (A2), tetraploid G. hirsutum acc. TM-1 (AD1), and G. barbadense acc. 3–79 (AD2), respectively. The orthologous genes were not one-to-one correspondence in the diploid and tetraploid cotton species, implying changes in the number of Chis in different cotton species during the evolution of Gossypium. Phylogenetic classification indicated that these Chis could be classified into six groups, with distinguishable structural characteristics. The expression patterns of Chis indicated their various expressions in different organs and tissues, and in the V. dahliae response. Silencing of Chi23, Chi32, or Chi47 in cotton significantly impaired the resistance to V. dahliae, suggesting these genes might act as positive regulators in disease resistance to V. dahliae. PMID:27354165

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

    Institute of Scientific and Technical Information of China (English)

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

    2016-01-01

    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.

  5. Functional analysis of autophagy genes via Agrobacterium-mediated transformation in the vascular Wilt fungus Verticillium dahliae.

    Science.gov (United States)

    Zhou, Lei; Zhao, Jun; Guo, Wangzhen; Zhang, Tianzhen

    2013-08-20

    Autophagy is a widely conserved intracellular process for degradation and recycling of proteins, organelles and cytoplasm in eukaryotic organisms and is now emerging as an important process in foliar infection by many plant pathogenic fungi. However, the role of autophagy in soil-borne fungal physiology and infection biology is poorly understood. Here, we report the establishment of an Agrobacterium tumefaciens-mediated transformation (ATMT) system and its application to investigate two autophagy genes, VdATG8 and VdATG12, by means of targeted gene replacement and complementation. Transformation of a cotton-infecting Verticillium dahliae strain Vd8 with a novel binary vector pCOM led to the production of 384 geneticin-resistant transformants per 1 × 10(6) conidia. V. dahliae mutants lacking either VdATG8 or VdATG12 exhibited reduced conidiation and impaired aerial hyphae production. Disease development on Arabidopsis plants was slightly delayed when inoculated with VdATG8 or VdATG12 gene deletion mutants, compared with the wild-type and gene complemented strains. Surprisingly, in vitro inoculation with unimpaired roots revealed that the abilities of root invasion were not affected in gene deletion mutants. These results indicate that autophagy is necessary for aerial hyphae development and plant colonization but not for root infection in V. dahliae.

  6. Discovery and identification of candidate genes from the chitinase gene family for Verticillium dahliae resistance in cotton.

    Science.gov (United States)

    Xu, Jun; Xu, Xiaoyang; Tian, Liangliang; Wang, Guilin; Zhang, Xueying; Wang, Xinyu; Guo, Wangzhen

    2016-06-29

    Verticillium dahliae, a destructive and soil-borne fungal pathogen, causes massive losses in cotton yields. However, the resistance mechanism to V. dahilae in cotton is still poorly understood. Accumulating evidence indicates that chitinases are crucial hydrolytic enzymes, which attack fungal pathogens by catalyzing the fungal cell wall degradation. As a large gene family, to date, the chitinase genes (Chis) have not been systematically analyzed and effectively utilized in cotton. Here, we identified 47, 49, 92, and 116 Chis from four sequenced cotton species, diploid Gossypium raimondii (D5), G. arboreum (A2), tetraploid G. hirsutum acc. TM-1 (AD1), and G. barbadense acc. 3-79 (AD2), respectively. The orthologous genes were not one-to-one correspondence in the diploid and tetraploid cotton species, implying changes in the number of Chis in different cotton species during the evolution of Gossypium. Phylogenetic classification indicated that these Chis could be classified into six groups, with distinguishable structural characteristics. The expression patterns of Chis indicated their various expressions in different organs and tissues, and in the V. dahliae response. Silencing of Chi23, Chi32, or Chi47 in cotton significantly impaired the resistance to V. dahliae, suggesting these genes might act as positive regulators in disease resistance to V. dahliae.

  7. 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.

  8. Control algorithms for dynamic attenuators

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Scott S., E-mail: sshsieh@stanford.edu [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Pelc, Norbert J. [Department of Radiology, Stanford University, Stanford California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States)

    2014-06-15

    Purpose: The authors describe algorithms to control dynamic attenuators in CT and compare their performance using simulated scans. Dynamic attenuators are prepatient beam shaping filters that modulate the distribution of x-ray fluence incident on the patient on a view-by-view basis. These attenuators can reduce dose while improving key image quality metrics such as peak or mean variance. In each view, the attenuator presents several degrees of freedom which may be individually adjusted. The total number of degrees of freedom across all views is very large, making many optimization techniques impractical. The authors develop a theory for optimally controlling these attenuators. Special attention is paid to a theoretically perfect attenuator which controls the fluence for each ray individually, but the authors also investigate and compare three other, practical attenuator designs which have been previously proposed: the piecewise-linear attenuator, the translating attenuator, and the double wedge attenuator. Methods: The authors pose and solve the optimization problems of minimizing the mean and peak variance subject to a fixed dose limit. For a perfect attenuator and mean variance minimization, this problem can be solved in simple, closed form. For other attenuator designs, the problem can be decomposed into separate problems for each view to greatly reduce the computational complexity. Peak variance minimization can be approximately solved using iterated, weighted mean variance (WMV) minimization. Also, the authors develop heuristics for the perfect and piecewise-linear attenuators which do not requirea priori knowledge of the patient anatomy. The authors compare these control algorithms on different types of dynamic attenuators using simulated raw data from forward projected DICOM files of a thorax and an abdomen. Results: The translating and double wedge attenuators reduce dose by an average of 30% relative to current techniques (bowtie filter with tube current

  9. Screening and Identification of Cotton Verticillium Wilt Antagonistic Bacteria Strain 7-30%棉花黄萎病拮抗细菌7-30菌株的筛选与鉴定

    Institute of Scientific and Technical Information of China (English)

    雷白时; 姜军坡; 王伟; 张冬冬; 王全; 朱宝成

    2008-01-01

    [Objective]The aim of this study was to screen the antagonistic spore-forming bacteria of Verticillium dahliae and identify its physiological and biochemical characteristics. [Method]Taking the cotton verticillium wilt pathogen Verticillium dahliae V-190 as the test microorganism, the antagonistic spore-forming bacteria were screened. Through the preliminary screening and secondary screening, an antagonistic bacteria strain 7-30 with stronger antibacterial activity was obtained, and its morphological characteristics, physiological and biochemical characteristics were also identified. [Result]84 antagonistic bacteria strains were isolated from soil in various places by the preliminary screening. Especially, 18 strains with better antagonistic ability were screened again, so an antagonistic bacteria strain 7-30 with the diameter of inhibition zone 18.9 mm and stronger antibacterial activity was obtained. According to its morphological characteristics, physiological and biochemical characteristics, the antagonistic bacteria strain 7-30 was identified as Bacillus subtilis primarily. [Conclusion]The strain 7-30 was obtained as the antagonistic spore-forming bacteria of Verticillium dahliae.

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

    Directory of Open Access Journals (Sweden)

    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.

  11. 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

  12. The Thioredoxin GbNRX1 Plays a Crucial Role in Homeostasis of Apoplastic Reactive Oxygen Species in Response to Verticillium dahliae Infection in Cotton1[OPEN

    Science.gov (United States)

    Zhang, Jie; Sun, Shu-Tao; Feng, De-Qin; Yang, Chun-Lin; Sun, Yong-Duo; Zhong, Nai-Qin

    2016-01-01

    Examining the proteins that plants secrete into the apoplast in response to pathogen attack provides crucial information for understanding the molecular mechanisms underlying plant innate immunity. In this study, we analyzed the changes in the root apoplast secretome of the Verticillium wilt-resistant island cotton cv Hai 7124 (Gossypium barbadense) upon infection with Verticillium dahliae. Two-dimensional differential gel electrophoresis and matrix-assisted laser desorption/ionization tandem time-of-flight mass spectrometry analysis identified 68 significantly altered spots, corresponding to 49 different proteins. Gene ontology annotation indicated that most of these proteins function in reactive oxygen species (ROS) metabolism and defense response. Of the ROS-related proteins identified, we further characterized a thioredoxin, GbNRX1, which increased in abundance in response to V. dahliae challenge, finding that GbNRX1 functions in apoplastic ROS scavenging after the ROS burst that occurs upon recognition of V. dahliae. Silencing of GbNRX1 resulted in defective dissipation of apoplastic ROS, which led to higher ROS accumulation in protoplasts. As a result, the GbNRX1-silenced plants showed reduced wilt resistance, indicating that the initial defense response in the root apoplast requires the antioxidant activity of GbNRX1. Together, our results demonstrate that apoplastic ROS generation and scavenging occur in tandem in response to pathogen attack; also, the rapid balancing of redox to maintain homeostasis after the ROS burst, which involves GbNRX1, is critical for the apoplastic immune response. PMID:26869704

  13. The Mitogen-Activated Protein Kinase Kinase VdPbs2 of Verticillium dahliae Regulates Microsclerotia Formation, Stress Response, and Plant Infection

    Science.gov (United States)

    Tian, Longyan; Wang, Yonglin; Yu, Jun; Xiong, Dianguang; Zhao, Hengjun; Tian, Chengming

    2016-01-01

    Verticillium dahliae, a ubiquitous phytopathogenic fungus, forms resting structures, known as microsclerotia that play crucial roles in Verticillium wilt diseases. VdHog1, a mitogen-activated protein kinase (MAPK), controls microsclerotia formation, virulence, and stress response in V. dahliae. In this study, we present detailed evidence that the conserved upstream component of VdHog1, VdPbs2, is a key regulator of microsclerotia formation, oxidative stress and fungicide response and plant virulence in V. dahliae. We identified VdPbs2, homologous to the yeast MAPK kinase Pbs2. Similar to the VdHog1 deletion mutant, VdPbs2 deletion strains exhibited delayed melanin synthesis and reduced formation of microsclerotia. When exposed to stresses, VdPbs2 mutants were more sensitive than the wild type to osmotic agents and peroxide, but more resistant to inhibitors of cell wall synthesis and some fungicides. Finally, VdPbs2 deletion mutants exhibited reduced virulence on smoke tree and tobacco seedlings. When taken together, we implicate that VdPbs2 and VdHog1 function in a cascade that regulates microsclerotia formation and virulence, but not all VdHog1 dependent functions are VdPbs2 regulated. This study thus provides novel insights into the signal transduction mechanisms that regulate microsclerotia formation and pathogenesis in this fungus. PMID:27729908

  14. Seismic attenuation in fractured media

    International Nuclear Information System (INIS)

    The prime objective of this paper is to quantitatively estimate seismic attenuation caused by fractures with different physical parameters. In seismic wave simulation, the fractured media are treated as the anisotropic media and fractures are represented by frequency-dependent elastic constants. Based on numerical experiments with three different parameters, namely viscosity, porosity and the Lamé parameters, this paper has the following observations. First, seismic attenuation is not affected by the viscosity within fractures, although it increases with the increase of porosity and decreases with the increase of the Lamé parameters within fractures. Among the latter two parameters, seismic attenuation is more sensitive to the Lamé parameters than to the porosity. Second, for the attenuation anisotropy, low frequencies have more anisotropic effect than high frequencies. For example, a 50 Hz wavefield has the strongest anisotropy effect if compared to 100 and 150 Hz wavefields. The attenuation anisotropy for low frequency (say 50 Hz) is more sensitive to the viscosity than the porosity and the Lamé parameters have the weakest effect among these three parameters. These observations suggest that low-frequency seismic attenuation, and especially the attenuation anisotropy in low frequency, would have great potential for fluid discrimination within fractured media. (paper)

  15. NO and H2O2 induced by Verticillium dahliae toxins and its influence on the expression of GST gene in cotton suspension cells

    Institute of Scientific and Technical Information of China (English)

    JIA ZhiQi; YUAN HaiYong; Li YingZhang

    2007-01-01

    Nitric oxide (NO) and hydrogen peroxide (H2O2) have been shown to be important signaling molecules that participate in the regulation of several physiological processes.In particular,they have significant role in plant resistance to pathogens by contributing to induction defense genes.Here,whether NO and H2O2 participate in the resistance responses against Verticillium dahliae toxins (VD-toxins) and their effects on the expression of GSTgene are studied.The results reveal that NO and H2O2 are produced as part of a complex network of signals that respond to VD-toxins and may converge to function both synergistically and independently by inducing resistant responses.GSTgene is potentially involved in the resistance mechanism in the cotton suspension cells.NO induces the expression of GSTgene independently of H2O2,H2O2 may be a more potent signal in the resistance responses against VD-toxins.

  16. Complete genome sequence of Pseudomonas fluorescens strain PICF7, an indigenous root endophyte from olive (Olea europaea L.) and effective biocontrol agent against Verticillium dahliae.

    Science.gov (United States)

    Martínez-García, Pedro Manuel; Ruano-Rosa, David; Schilirò, Elisabetta; Prieto, Pilar; Ramos, Cayo; Rodríguez-Palenzuela, Pablo; Mercado-Blanco, Jesús

    2015-01-01

    Pseudomonas fluorescens strain PICF7 is a native endophyte of olive roots. Previous studies have shown this motile, Gram-negative, non-sporulating bacterium is an effective biocontrol agent against the soil-borne fungus Verticillium dahliae, the causal agent of one of the most devastating diseases for olive (Olea europaea L.) cultivation. Here, we announce and describe the complete genome sequence of Pseudomonas fluorescens strain PICF7 consisting of a circular chromosome of 6,136,735 bp that encodes 5,567 protein-coding genes and 88 RNA-only encoding genes. Genome analysis revealed genes predicting factors such as secretion systems, siderophores, detoxifying compounds or volatile components. Further analysis of the genome sequence of PICF7 will help in gaining insights into biocontrol and endophytism.

  17. Effect of Verticillium lecanii on biological characteristics and life table of Serangium japonicum (Coleoptera: Coccinellidae), a predator of whiteflies under laboratory conditions

    Institute of Scientific and Technical Information of China (English)

    Lazreg Fatiha; Zhen Huang; Shun-Xiang Ren; Shaukat Ali

    2008-01-01

    Effects of entomopathogenic fungus Verticillium lecanii on biological characteristics and life table of Serangiumjaponicum, a predator of whiteflies against five different conidial concentrations (1×104, 1×105, 1×106, 1×107, and 1×108 conidia/mL) were studied under laboratory conditions. The developmental periods for all immature stages (from eggs, 1st, 2nd, 3rd, 4th instar nymph and pupae up to emergence) among the treatments were significantly different when compared to that of control, and the longest development period was observed as treated with 1×108spore/mL. However, no significant difference on the percent survival of all immature stages was observed among the treatments and control. Also, there were no significantly different effects of V. lecanii on mean generation time, intrinsic rate, the finite rate of increase and longevity of S. japonicum among the treatments and control.

  18. MPG1基因驱动GFP基因在大丽轮枝菌中表达%The MPG1 Gene Act as Promoter to Drive GFP Gene to Express in Verticillium dahlia

    Institute of Scientific and Technical Information of China (English)

    张斯; 柳燕; 徐婷婷; 吕乐; 竺锡武; 陈集双

    2015-01-01

    To study whether the MPG1 gene were used as the promoter to drive GFP gene to express in Verticillium dahlia, via Agrobacterium tumefaciens-mediated transformation the pHMG vector with MPG1-eGFP gene were transformed into spores of the Verticillium dahlia T-9. There were 80 transformants each 106 spores. The green fluorescence was found from the spores and hypha of the transformants by the Fluorescence Microscope. By the genomic DNA-PCR and western blot, the results also suggested that the GFP gene were expressed in Verticillium dahlia. All the results showed that the MPG1 gene could act as a promoter to drive GFP gene to expression in Verticillium dahlia.%为了探讨以MPG1基因作为启动子能否驱动GFP基因在大丽轮枝菌中表达,采用根癌农杆菌介导的真菌遗传转化方法,将含有MPG1-eGFP表达盒的pHMG载体转化入棉花大丽轮枝菌T-9中。经抗生素筛选后转化子约80个/106孢子,荧光显微镜观察转化子菌株孢子和菌丝在荧光显微镜下均发出绿色荧光,基因组DNA-PCR检测、GFP蛋白western blot检测表明,GFP蛋白在大丽轮枝菌转化子中成功表达。结果表明,MPG1基因作为启动子成功驱动GFP基因在大丽轮枝菌中转录表达。

  19. Isolation, Identification and Activity of an Antagonistic Spore Bacterium against Cotton Verticillium Wilt%一株棉花黄萎病拮抗芽孢细菌的分离鉴定及活性检测

    Institute of Scientific and Technical Information of China (English)

    张冬冬; 李术娜; 郭晓军; 朱宝成

    2012-01-01

    采用改良的琼脂平板扩散法,通过初筛和复筛,得到一株对棉花黄萎病病原菌大丽轮枝菌(Verticillium dahliae)具有较强的抑菌活性的拮抗细菌Z-5菌株.通过对该菌株的形态特征观察、生理生化鉴定和16S rDNA 的序列分析,确定拮抗细菌Z-5菌株为Bacillus malacitensis.盆栽实验表明Z-5菌株对大丽轮枝菌的防治效果达到76.05%,对棉花黄萎病具有明显的防治作用.%A bacterial strain called Z-5 that had strong inhibition capability against Verticillium dahliae V-190 was obtained via preliminary and secondary screening with the improved agar plate diffusion method. Characterized by morphological and cultural features observation, physiological and biochemical experiments, and 16S rDNA sequence analysis, the Z-5 strain was initially identified as Bacillus malacitensis. Control of cotton Verticillium wilt by this antagonistic bacterium was assessed via potted plants. Results showed that the control efficacy of the antagonistic Z-5 strain on cotton Verticillium wilt was 76.05%. Preliminary results demonstrated that the antagonistic Z-5 bacterial strain could significantly inhibit the growth of V. dahliae.

  20. A Strain of Verticillium Lecanii was Screened and its Control Effect of Hibiscus Aphid%一株蜡蚧轮枝菌的筛选及其防治木槿蚜虫的效果

    Institute of Scientific and Technical Information of China (English)

    王金昌; 靳亮

    2015-01-01

    We screened a strain of Verticillium lecanii from the hibiscus aphid body and have done the toxicity test and field control experiments of controlling Hibiscus aphid. The results show that the screened strain of this Verticillium lecanii has strong virulence for killing Hibiscus aphid. Field spra-ying controlled Hibiscus aphid,afer 7 d Hibiscus aphid population decreased by 79. 9%,reached the effect of field controlling of Hibiscus aphid. So the strain of Verticillium lecanii has a good prospect of development and application.%实验从木槿蚜虫体内筛选到一株蜡蚧轮枝菌真菌,对其进行了防治木槿蚜虫的室内毒力测试和田间防治的实验,结果表明筛选到的这株蜡蚧轮枝菌真菌对木槿蚜虫有较强的毒力. 田间防治施药7d后木槿蚜虫虫口基数减少了79. 9%,具有很好的开发应用前景.

  1. Estimation of Water Vapour Attenuation And Rain Attenuation

    Directory of Open Access Journals (Sweden)

    K.Kalyana Srinivas

    2015-04-01

    Full Text Available Attenuation due to and water vapour and rain can severely degrade the radio wave propagation at centimeter or millimeter wavelengths. It restricts the path length of radio communication systems and limits the use of higher frequencies for line-of-sight microwave links and satellite communications. The attenuation will pose a greater problem to communication as the frequency of occurrence of heavy rain increases.In a tropical region, like Malaysia, where excessive rainfall is a common phenomenon throughout the year, the knowledge of the rain attenuation at the frequency of operation is extremely required for the design of a reliable terrestrial and earth space communication link at a particular location.

  2. The attenuation and the attenuators: strategies and tactics

    Directory of Open Access Journals (Sweden)

    Antonio Briz

    2013-12-01

    Full Text Available This work is inscribed in a research project (ES.POR.ATENUAÇÃO that seeks to analyze and explain the attenuator activity in different regional varieties of Spanish and Portuguese, in order to perform, subsequently, different contrastive intralinguistic and interlinguistic studies. In this article, we explain some of the theoretical and methodological principles on which are based the qualitative and quantitative analysis. And especially, we will refer to the concept of attenuation (Briz 1995, 2002, 2003, 2005, 2007a, 2012.

  3. Multi-transmitting formula for attenuating waves

    Institute of Scientific and Technical Information of China (English)

    陈少林; 廖振鹏

    2003-01-01

    The MTF is extended to case of attenuating incident wave by introducing an attenuation coefficient. The reflection coefficients of this modified MTF and MTF areevaluated and compared when an attenuating wave impinges on the boundary, and the results demonstrate that MTF can be used to absorb slightly attenuating wavesand the modified MTF is more capable of absorbing heavily attenuating waves than MTF. The accuracy of modified MTF is also tested by numerical examples of fluid saturated porous media.

  4. Photoacoustic Imaging Taking into Account Attenuation

    CERN Document Server

    Kowar, Richard

    2010-01-01

    First, we review existing attenuation models and discuss their causality properties, which we believe to be essential for algorithms for inversion with attenuated data. Then, we survey causality properties of common attenuation models. We also derive integro-differential equations which the attenuated waves are satisfying. In addition we discuss the ill--conditionness of the inverse problem for calculating the unattenuated wave from the attenuated one.

  5. Sound attenuation in magnetorheological fluids

    Science.gov (United States)

    Rodríguez-López, J.; Elvira, L.; Resa, P.; Montero de Espinosa, F.

    2013-02-01

    In this work, the attenuation of ultrasonic elastic waves propagating through magnetorheological (MR) fluids is analysed as a function of the particle volume fraction and the magnetic field intensity. Non-commercial MR fluids made with iron ferromagnetic particles and two different solvents (an olive oil based solution and an Araldite-epoxy) were used. Particle volume fractions of up to 0.25 were analysed. It is shown that the attenuation of sound depends strongly on the solvent used and the volume fraction. The influence of a magnetic field up to 212 mT was studied and it was found that the sound attenuation increases with the magnetic intensity until saturation is reached. A hysteretic effect is evident once the magnetic field is removed.

  6. 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 biased...... at different points in the current-voltage characteristic. Both numerical calculations based on the Tien-Gordon theory and 70-GHz microwave experiments have confirmed the wide dynamic range (more than 15-dB attenuation for one stage) and the low insertion loss in the ''open'' state. The performance of a fully...... integrated submillimeter receiver circuit which comprises a flux-flow oscillator (FFO) as local oscillator, a superconducting variable attenuator, and a microwave SIS detector with tuned-out capacitance is also reported....

  7. X-Ray Attenuation Cell

    Energy Technology Data Exchange (ETDEWEB)

    Ryutov, D.; Toor, A.

    2000-03-03

    To minimize the pulse-to-pulse variation, the LCLS FEL must operate at saturation, i.e. 10 orders of magnitude brighter spectral brilliance than 3rd-generation light sources. At this intensity, ultra-high vacuums and windowless transport are required. Many of the experiments, however, will need to be conducted at a much lower intensity thereby requiring a reliable means to reduce the x-ray intensity by many orders of magnitude without increasing the pulse-to-pulse variation. In this report we consider a possible solution for controlled attenuation of the LCLS x-ray radiation. We suggest using for this purpose a windowless gas-filled cell with the differential pumping. Although this scheme is easily realizable in principle, it has to be demonstrated that the attenuator can be made short enough to be practical and that the gas loads delivered to the vacuum line of sight (LOS) are acceptable. We are not going to present a final, optimized design. Instead, we will provide a preliminary analysis showing that the whole concept is robust and is worth further study. The spatial structure of the LCLS x-ray pulse at the location of the attenuator is shown in Fig. 1. The central high-intensity component, due to the FEL, has a FWHM of {approx}100 {micro}m. A second component, due to the undulator's broad band spontaneous radiation is seen as a much lower intensity ''halo'' with a FWHM of 1 mm. We discuss two versions of the attenuation cell. The first is directed towards a controlled attenuation of the FEL up to the 4 orders of magnitude in the intensity, with the spontaneous radiation halo being eliminated by collimators. In the second version, the spontaneous radiation is not sacrificed but the FEL component (as well as the first harmonic of the spontaneous radiation) gets attenuated by a more modest factor up to 100. We will make all the estimates assuming that the gas used in the attenuator is Xenon and that the energy of the FEL is 8.25 keV. At

  8. 大丽轮枝菌(Verticillium dahliae VdLs.17)分泌组预测及分析%Prediction and Analysis of Verticillium dahliae VdLs.17 Secretome

    Institute of Scientific and Technical Information of China (English)

    田李; 陈捷胤; 陈相永; 汪佳妮; 戴小枫

    2011-01-01

    [Objective] The aim of this study was to predict and analyze secretome of Verticillium dahliae, an important soil-born fungal pathogen that causes vascular wilt diseases. [Method] The softwares SignalP, TargetP, TMHMM, Big-pi and PROSITE were used to predict the sectetome of V. Dahliae. Protein databases were used for secretome annotation to find putative pectinase, cellulose and pathogen-host interaction proteins. The proteins with common fungal effector character were investigated by a set of computer algorithms. By using BLASTP, the secretome of V. Dahliae and V. Albo-atrum was compared to find V. Dahliae specifically secreted proteins. [Result] A total of 922 possible secreted proteins were identified in V. Dahliae scretome. The most frequent amino acid in signal peptides is alanine, and the least is glutamic acid and aspartic acid. The amino acid in the position -3 and -1 are very conserved. The secretome is equipped with 158 carbohydrate-active enzymes which include 10 pectic hydrolases and 14 pectic lyases, 190 putative pathogen-host interaction proteins, 97 RxLx[EDQ] motif containing proteins and 52 small cysteine-rich secreted proteins, and 58 V. Dahliae specifically secreted proteins compared with V. Albo-atrum. [Conclusion] Thisstudy has provided secretome prediction algorithms for V. Dahliae. Length of signal peptides vary greatly. Composition of signal peptides are mainly aliphatic amino acid and sequences of signal peptides near C-terminal are conservative. V. Dahliae secretome are rich in potential pectinase, pathogen-host interaction protein, RxLx[EDQ] motif containing protein and small cysteine-rich protein which may play roles in V. Dahliae pathogenetic mechanism.%[目的]预测并分析大丽轮枝菌基因组范围内的分泌蛋白,为大丽轮枝菌分泌蛋白致病机理的研究奠定基础.[方法]利用已公布的大丽轮枝菌全基因组序列,组合使用生物信息学软件SignalP、TargetP、TMHMM、Big-pi和PROSITE,预测大丽

  9. Screening of microsclerotia defective mutants and analysis of the flanking sequence of Verticillium dahliae%大丽轮枝菌(Verticillium dahliae)微菌核缺陷突变体的筛选及其侧端序列分析

    Institute of Scientific and Technical Information of China (English)

    汪敏; 赵静; 李洪连; 谷素静; 马宗斌; 焦睿

    2015-01-01

    为了获得大丽轮枝菌(Verticillium dahliae)微菌核缺陷突变体,利用农杆菌介导转化大丽轮枝菌,共获得270个T-DNA随机插入突变体,从中筛选出了4个气生菌丝发达、不产微菌核的突变体,利用高效TAIL-PCR技术,获得了其侧端序列,结合生物信息学方法,获得4个突变体T-DNA在大丽轮枝菌基因组插入位点的基因信息.

  10. 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

  11. Formation conditions for microsclerotia of Verticillium dahliae%大丽轮枝孢微菌核的形成条件

    Institute of Scientific and Technical Information of China (English)

    白应文; 胡东芳; 胡小平; 赵俊兴; 朱荷琴; 杨家荣

    2011-01-01

    以棉花黄萎病菌Verticillium dahliae XJ2008菌株为试材,研究了培养基类型、pH值、温度等因素对棉花黄萎病菌微菌核形成的影响,确立了微菌核形成的最佳培养条件,并对采自新疆、江苏、河南、陕西、山东等地的15个棉花黄萎病菌菌株进行了测试.结果表明,适合于棉花黄萎病菌微菌核大量产生的培养基为基础改良培养基(BMM)、pH值为9.5-11.5、温度为20℃.在该条件下,15个大丽轮枝孢菌株在接种后第12天即可产生大量的微菌核,不同菌株产生微菌核的数量及大小间存在着显著差异,但均与病菌的致病性无相关性.%The effects of medium types, Ph value and temperature on microsclerotium formation were investigated by using Verticillium dahliae strain XJ2008 as experiment material. The optimum condition was established and used to test the microsclerotium formation of 15 V. Dahliae strains collected from Xinjiang, Jiangsu, Henan, Shaanxi and Shandong. Results showed that the medium for microsclerotium formation in large scale was basal agar medium modified (BMM), with Ph ranging from 9.5 to 11.5 and temperature of 20℃. Under this condition, 15 strains could produce abundant microsclerotia after inoculation for 12 days. The quantity and size of microsclerotia among the 15 strains have significant difference, and they bear no relationship with the pathogenicity of the strains.

  12. 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...

  13. Stormwater Attenuation by Green Roofs

    Science.gov (United States)

    Sims, A.; O'Carroll, D. M.; Robinson, C. E.; Smart, C. C.

    2014-12-01

    Innovative municipal stormwater management technologies are urgently required in urban centers. Inadequate stormwater management can lead to excessive flooding, channel erosion, decreased stream baseflows, and degraded water quality. A major source of urban stormwater is unused roof space. Green roofs can be used as a stormwater management tool to reduce roof generated stormwater and generally improve the quality of runoff. With recent legislation in some North American cities, including Toronto, requiring the installation of green roofs on large buildings, research on the effectiveness of green roofs for stormwater management is important. This study aims to assess the hydrologic response of an extensive sedum green roof in London, Ontario, with emphasis on the response to large precipitation events that stress municipal stormwater infrastructure. A green roof rapidly reaches field capacity during large storm events and can show significantly different behavior before and after field capacity. At field capacity a green roof has no capillary storage left for retention of stormwater, but may still be an effective tool to attenuate peak runoff rates by transport through the green roof substrate. The attenuation of green roofs after field capacity is linked to gravity storage, where gravity storage is the water that is temporarily stored and can drain freely over time after field capacity has been established. Stormwater attenuation of a modular experimental green roof is determined from water balance calculations at 1-minute intervals. Data is used to evaluate green roof attenuation and the impact of field capacity on peak flow rates and gravity storage. In addition, a numerical model is used to simulate event based stormwater attenuation. This model is based off of the Richards equation and supporting theory of multiphase flow through porous media.

  14. Isolation and identification of the antagonistic strain DM-54 of Bacillus amyloliquefacien against Verticillium dahliae, and optimization of antifungal protein producing conditions

    Institute of Scientific and Technical Information of China (English)

    Ying ZHU; Shuna LI; Hongshui YUAN; Xiaojun GUO; Baocheng ZHU

    2009-01-01

    The strains capable of resistance against Verticillium dahliae Kleb were isolated and screened from the soils of cotton fields from several different provinces in China. A strain, coded DM-54, with a rather high antagonistic activity was obtained. Its morphological characteristics, physiological and biochemical properties and a 16 S rDNA sequence of this strain were further studied. The DM-54 strain was finally identified as a kind of Bacillus amyloliquefacien. Through a single factor experiment and an orthogonal experiment, the optimal shaking flask fermentation condition of strain DM-54 was found to be: media composed of 5% dextrin, 3% soy peptone, 0.02% MgSO4 0.01% CaCl2, initial pH 7.0 and 10% inoculum volume, media volume 30/250 (mL/mL), fermentation temperature at 32℃, rotating speed activity was distinguished to be elevated, at about 39.9%. Our research offers an effective means for the massive production of antagonistic proteins.

  15. Assessment of genetic diversity among Chinese upland cottons with Fusarium and/or Verticillium wilts resistance by AFLP and SSR markers

    Institute of Scientific and Technical Information of China (English)

    WANG Xingfen; MA Jun; YANG Shuo; ZHANG Guiyin; MA Zhiying

    2007-01-01

    Genetic diversity among 95 Chinese upland cottons with Fusarium and/or Verticillium wilts resistance was estimated using Amplified Fragment Length Polymorphism (AFLP) and Simple Sequence Repeat (SSR) markers.Twenty EcoRI-MseI AFLP and 19 SSR primers with polymorphism were selected to perform the fingerprinting.The results showed that 20 AFLP primer pairs produced a total of 1 480 major bands among 95 genotypes,and 214 were polymorphic bands.The number of total bands per primer pair ranged from 47 to 109,with an average of 74.0.The polymorphism information content (PIC) values for the 20 primer pairs varied from 0.01 (E-ACT/M-CAT) to 0.24 (E-ACA/MCTA),and the average value was 0.09.Nineteen SSR primers generated 89 DNA bands,of which 61 were polymorphic.The total number of alleles per locus varied from 3 to 8,with an average of 4.7.The average PIC value for the SSR amplification products was 0.69.Genetic similarity estimates for the entire data set ranged from 0.978 to 0.998 based on AFLP and SSR bands.It was proved that the close genetic relationship and narrow genetic diversity existed in the tested cultivars.The clustering patterns could not be correlated to the geographic origin,the pedigree and common parentage of the cultivars.

  16. A study of the changes in quantitative activity of some enzymes in olive cultivars during the interaction between Verticillium wilt and root-knot nematode.

    Science.gov (United States)

    Saeedizadeh, Ayatollah; Kheiri, Ahmad; Zad, Javad; Etebarian, Hasan Reza; Bandani, Ali Reza; Sharifi, Rouhollah

    2009-01-01

    Second stage juvenile (J2) of root-knot nematode, Meloidogyne javanica, and microsclerotia of verticilliosis, Verticillium dahliae, were used as the source of inoculum for nematode and fungus respectively. One-year-old seedlings of olive cultivar, Zard, Roghani, Koroneiki and Manzanilla, were transplanted to pots containing 2000g of sterilized sandy loam soil. Experiment was conducted in completely randomized design with 32 Treatments and five replications. Treatments were as follows: control, nematode alone, fungus alone and fungus+nematode. Pots were inoculated with (0, 2000, 3000, 4000) J2 of nematode and/or (10 no/g soil) microsclerotia of fungus according to the treatments. Quantitative activity of soluble proxidase, cell wall bounded proxidase, beta-1,3-glucanase and B-1,4-glucanase were determined by the pirocatechol, hydrogen proxide, guaiacol and laminarin-dinitrosalicylilate methods, respectively, on 1,10, 20 and 30 days after inoculation. Results showed that these enzymes in leaves and roots of seedlings inoculated with pathogens increased (p Manzanilla, respectively (p < or = 0/05). PMID:20222618

  17. 大丽轮枝菌的含钼协同因子基因位点%ON MOLYBDENUM COFACTOR GENE LOCI OF VERTICILLIUM DAHLIAE

    Institute of Scientific and Technical Information of China (English)

    罗才宏; 王克荣

    2000-01-01

    @@ 含钼协同因子在一些真菌中是硝酸还原酶和黄嘌呤脱氢酶Ⅰ和Ⅱ的辅助因子;在用KClO3为诱变剂以获得nit突变体的试验中,nitB型突变体就是由于该辅酶的基因位点发生突变所致(Marsluf,1981).利用nitB突变体测定含钼协同因子的基因位点,在不同的真菌中得到的结果不同.Cove(1979)测出的Aspergillus nidulans Wint含钼协同因子有五个基因位点,Newton(1988)测定Septoria nodorum Berk.的结果是四个.作者在做营养体亲和性分析时,观察到大丽轮枝菌(Verticillium dahliae Kleb.)的nitB突变体可以互补.但迄今为止,有关此菌的含钼协同因子的基因位点还未见报道.本试验的目的,在于通过nitB之间的互补性测定,推断出该菌的含钼协同因子基因位点的数目.

  18. Evaluation of ITS region for DNA barcoding of Verticillium spp.%ITS片段作为轮枝菌DNA条形码的评价研究

    Institute of Scientific and Technical Information of China (English)

    段维军; 张慧丽; 郭立新; 顾建锋; 陈先锋; 张祥林; 夏侯阳

    2013-01-01

    以轮枝菌属中的重要植物病原性轮枝菌及其近似种共13种35个菌株为材料,探讨ITS片段作为轮枝菌DNA条形码的可行性.结果表明,ITS成功区分了研究涉及的10个种,其PCR扩增和测序成功率为97.1%,序列鉴定成功率为94.5%,但对个别亲缘关系较近种的物种鉴别能力较弱.%In this study,the ITS fragment was tested with 35 strains of 13 species of the Verticillium spp.to investigate its feasibility as a DNA barcode.The results revealed that ITS showed appropriate intra-and inter-specific variations,and could distinguish the investigated 10 species of the genus.It was easy for PCR amplification and sequencing.The correct identification rate is 94.5% for the sequences tested.However,the inter-specific differences of ITS in some closely-related isolates were more than the intra-specific differences.

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

    Directory of Open Access Journals (Sweden)

    Srivathsa Nallanchakravarthula

    Full Text Available 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.

  20. 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. PMID:25347069

  1. Cultivation-independent analysis of Pseudomonas species in soil and in the rhizosphere of field-grown Verticillium dahliae host plants.

    Science.gov (United States)

    Costa, Rodrigo; Salles, Joana Falcão; Berg, Gabriele; Smalla, Kornelia

    2006-12-01

    Despite their importance for rhizosphere functioning, rhizobacterial Pseudomonas spp. have been mainly studied in a cultivation-based manner. In this study a cultivation-independent method was used to determine to what extent the factors plant species, sampling site and year-to-year variation influence Pseudomonas community structure in bulk soil and in the rhizosphere of two Verticillium dahliae host plants, oilseed rape and strawberry. Community DNA was extracted from bulk and rhizosphere soil samples of flowering plants collected at three different sites in Germany in two consecutive years. Pseudomonas community structure and diversity were assessed using a polymerase chain reaction denaturing gradient gel electrophoresis (PCR-DGGE) system to fingerprint Pseudomonas-specific 16S rRNA gene fragments amplified from community DNA. Dominant and differentiating DGGE bands were excised from the gels, cloned and sequenced. The factors sampling site, plant species and year-to-year variation were shown to significantly influence the community structure of Pseudomonas in rhizosphere soils. The composition of Pseudomonas 16S rRNA gene fragments in the rhizosphere differed from that in the adjacent bulk soil and the rhizosphere effect tended to be plant-specific. The clone sequences of most dominant bands analysed belonged to the Pseudomonas fluorescens lineage and showed closest similarity to culturable Pseudomonas known for displaying antifungal properties. This report provides a better understanding of how different factors drive Pseudomonas community structure and diversity in bulk and rhizosphere soils. PMID:17107555

  2. 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).

  3. Pattern Analysis of the Interaction between Verticillium dahliae Strains and Cotton Varieties%棉花黄萎病菌与品种互作的格局分析

    Institute of Scientific and Technical Information of China (English)

    吴元奇; 房卫平; 胡秉民

    2009-01-01

    In order to study the interaction pattern of strains and cotton varieties, the disease indices of twenty-three different resistant or susceptible varieties inoculating 18 isolates of Verticillium dahliae were analyzed by biplot method based on cluster analysis. The results showed that 23 cotton cultivars were grouped into six clusters, and 18 Verticillium dahliae strains were clustered into five groups. With the highest resistance to all strain groups, variety cluster G1 which was consisted of two lines (5031 and 50312) could be used as good resistant resource in breeding of Verticillium wilt resistance. There is a high host-pathogen interaction between strain group S4 and variety group G5. As dominant strains and with the highest pathogenicity, S4 consisting of 4 Verticillium dahliae strains among which VD25 came from Chengan of Hebei Province and the rest, named as XS4, XS6, and XS7 all from Changshu of Jiangsu Province, should be very important in identifying and breeding for Verticillium wilt resistance. Strain groups S2 and S3, which highly interacted with 3 variety groups (accounting for 56% of the tested material), might be the potential dominant strains. With average resistance to all strains, variety group G2 was the excellent host for Verticillium dahliae.%以23个棉花品种(系)接种18个黄萎病菌株的抗感表现(病情指数)为分析对象,在聚类分析的基础上用双标图方法研究了寄主-病原的互作格局.结果表明:23个棉花品种分为6个抗病性不同的品种组,18个菌株聚为5个致病力不同的菌株群.5031和50312组成的品种组G1对所有菌株群具有最高抗性,可作为抗黄育种的高抗质源.来自河北成安的VD25与来自江苏常熟的XS4、XS6和XS7组成的菌株群S4与G5品种组存在互作,其致病力最强,是棉花黄萎病的优势菌株群,在抗黄育种和抗黄鉴定中应予以高度重视.S2和S3菌株群与56%的参试品种构成的3个品种组间存在互作,是潜在的

  4. 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.

  5. 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.

  6. 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. 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 prospe

  2. Simple parameterization of nuclear attenuation data

    CERN Document Server

    Akopov, N; Akopov, Z

    2007-01-01

    Based on the nuclear attenuation data obtained by the HERMES experiment on nitrogen and krypton nuclei, it is shown that the nuclear attenuation $R_M^{h}$ can be parametrised in a form of a linear polynomial $P_1=a_{11}$ + $\\tau a_{12}$, where $\\tau$ is the formation time, which depends on the energy of the virtual photon $\

  3. 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 ...

  4. 棉秆生物炭对大丽轮枝菌生长及毒素作用的影响%Influences of cotton biochar on growth and toxin effect of Verticillium dahliae

    Institute of Scientific and Technical Information of China (English)

    马云艳; 顾美英; 徐万里; 王东胜; 孙跃跃; 薛泉宏

    2015-01-01

    The verticillium wilt of cotton is difficult to control because microsclerotia formed by Verticillium dahlia kleb .can resist the adverse environment and allow a long-term survival in the soil .The application of cotton biochar can overcome the disadvantages of straw returning and prevent the entrance of Verticillium dahlia kled .into the soil .The ob-jective of this study is to explore the influence mechanism of cotton biochar on Verticillium dahlia kleb .by examinig the effects of cotton biochar on the mycelial growth ,microsclerotium germination and toxin secretion of Verticillium dahlia kleb .Shake cultivation and plate culture were used to test the resulting influences of cotton biochar on the mycelial growth of V . dahlia and the germination of microsclerotium .The dish dipping method was used to observe the germina-tion of cotton seed and melon seed to investigate the effects of biochar on reducing toxicity of Verticillium dahlia .Results showed that cotton biochar had no significant effects on the mycelial growth of V . dahlia under liquid culturing condi-tion ,while it had promotional effects under solid culture condition .In addition ,cotton biochar inhibited the germination rate of the microsclerotium .As treatment time went on ,the inhibition effect became disappeared .Moreover ,the addition of cotton biochar seriously reduced the toxicity of V . dahlia under liquid culture conditions .At the mid-stage of liquid culturation ,cotton seed germination rates were 53 .3% and 33 .3% after 12 days in the treatments of 2 .0 g·L-1 biochar and CK ,respectively ( P<0 .05) .At the prophase ,middle and late stages ,the seedling length with the treatment of 0 .5 g·L-1 biochar were 3 .9 ,1 .1 and 2 .2 times more than that with the CK treatment ,respectively .Compared to CK , biochar enhanced the melon seed germination , radicle length , plumule length and seedling length . In conclusion , biochar could slightly inhibit the mycelial growth and microsclerotium

  5. The Influence of the Verticillium dahliae Kleb Infection on the Anti-Enzyme Inside the Body of the Cotton with Different Root Injured Degree

    Institute of Scientific and Technical Information of China (English)

    FAN Wei-wei; WANG Li-an; MA Chun-hong; DONG Wen-qi; LI Yun-chao; LIU Zi-hui; JIA Yin-Suo; GENG Jun-yi; ZHANG Xiang-yun

    2007-01-01

    This study was to explore the influence of the Verticillium dahliae Kleb inflection on the anti-enzyme inside the body of the cotton with a different root injured degree. When the cotton seedling was long, with four leaves, it was flushed with water carefully, and then the following were obtained: (1) complete root seedling; (2) cut root seedling - by cutting off the lower part, 3-5 cm of the root, with a disinfected knife; (3) injured root seedling - by cutting off most of the side roots, but keeping the main root. Three kinds of cotton seedlings with different roots were immersed separately in different concentrations of the germ liquid (V. dahliae) of 20 mL each. Through 0-48 h, the wilt degree of the seedling was recorded, and the related anti-enzyme of the variety was measured. After being immersed in the germ liquid, there was a significant difference in the wilt degree of the three kinds of injured root. When the germ liquid was in the ratio of 1:10, the complete root seedling was the lightest with no wilt; the injured root seedling was the second with a 2-degree wilt; but the cut root seedling was the most serious with a 3-degree wilt. At the same time, the changes in the peroxidase and malondialdehvde activities were determined.Peroxidase (POD) activities in the cut root seedling were 38.2 U mg-1 min-1, in the injured root seedling were 42.96 U mg-1 min-1, and in the complete root seedling were the highest at 49.2 U mg-1 min-1. The malondialdenvde (MDA)content in cut root seedling was 39.483 mmol g-1, injured root seedling was 27.12 mmol g-1, and the complete root seedling was only 3.845 mmol g-1. The activity of the related anti-enzymes, such as POD was high or low, the quantity of the MDA was more or less, which they met the order of the harm of the seedlings. The change of SOD activities in cut root seedling was the most obvious as well. After injuring and inflecting the young roots, the exterior pathological reaction of the seedling and the dynamic

  6. Verticillium dahliae race 2-specific PCR reveals a high frequency of race 2 strains in commercial spinach seed lots and delineates race structure.

    Science.gov (United States)

    Short, Dylan P G; Gurung, Suraj; Maruthachalam, Karunakaran; Atallah, Zahi K; Subbarao, Krishna V

    2014-07-01

    Two pathogenic races of Verticillium dahliae have been described on lettuce and tomato. Host resistance to race 1 is governed by plant immune receptors that recognize the race 1-specific fungal effector Ave1. Only partial resistance to race 2 exists in lettuce. Although polymerase chain reaction (PCR) assays are available to identify race 1, no complementary test exists to positively identify race 2, except for lengthy pathogenicity assays on host differentials. Using the genome sequences of two isolates of V. dahliae, one each from races 1 and 2, we identified potential markers and PCR primers to distinguish the two races. Several primer pairs based on polymorphisms between the races were designed and tested on reference isolates of known race. One primer pair, VdR2F-VdR2R, consistently yielded a 256-bp amplicon in all race 2 isolates exclusively. We screened DNA from 677 V. dahliae isolates, including 340 from spinach seedlots, with the above primer pair and a previously published race 1-specific primer pair. DNA from isolates that did not amplify with race 1-specific PCRs amplified with the race 2-specific primers. To validate this, two differential lines of lettuce were inoculated with 53 arbitrarily selected isolates from spinach seed and their pathogenicity and virulence were assessed in a greenhouse. The reactions of the differential cultivars strongly supported the PCR data. V. dahliae race structure was investigated in crops in coastal California and elsewhere using primers specific to the two races. All artichoke isolates from California were race 1, whereas nearly all tomato isolates were race 2. Isolates from lettuce, pepper, and strawberry from California as well as isolates from spinach seed from two of four countries comprised both races, whereas only race 2 was observed in cotton, mint, olive, and potato. This highlights the importance of identifying resistance against race 2 in different hosts. The technique developed in this study will benefit

  7. Screening and identification of intagonistic bacterium strain 8-52 against Verticillium dahliae%大丽轮枝菌拮抗细菌8-52菌株的筛选与鉴定

    Institute of Scientific and Technical Information of China (English)

    吴国江; 王占利; 李术娜; 王全; 李红亚; 朱宝成

    2009-01-01

    为筛选对棉花黄萎病病原菌大丽轮枝菌(Verticillium dahliae)具有拮抗作用的芽孢细菌,采用改良的琼脂平板扩散法,通过初筛从各地的土样中分离到83株拮抗细菌菌株,对其中的69株进行了复筛,得到一株具有较强的抑菌活性的拮抗细菌8-52菌株.对该菌株进行了形态特征的观察、生理生化试验和16S rDNA的序列分析.将该菌株的形态特征和生理生化特性鉴定的结果与相应种、属模式菌的性状相对照,认为菌株8-52与芽孢杆菌(Bacillus)的相应性状很相近.根据16S rDNA序列相似性分析,此菌株与Bacillus velezensis标准菌株AB245422的16S rDNA序列相似度达99.78%,因此鉴定拮抗菌株8-52为Bacillus velezensis.%In order to obtain antagonistic bacteria against Verticillium dahliae, 83 antagonistic strains were isolated and screened with the improved agar plate diffusion method from the soil of different districts. 69 strains of them were tested their antagonistic activity against Verticillium dahliae Kleb via secondary screening. As a result, a strain called 8-52 which had strong inhibition capability against Verticillum dahliae strain V-190 was obtained. Then the strain 8-52 was characterized by morphological and culture features observation, physiological and biochemical experiments, and 16S rDNA sequence analysis. As the morphology characteristics and physiological and biochemical characteristics of the stain are similar to Bacillus and the similarity of the 16S rDNA sequences between strain 8-52 and the type strain was up to 99.21%, the strain 8-52 was initially identified as Bacillus malacitensis.

  8. Live attenuated intranasal influenza vaccine.

    Science.gov (United States)

    Esposito, Susanna; Montinaro, Valentina; Groppali, Elena; Tenconi, Rossana; Semino, Margherita; Principi, Nicola

    2012-01-01

    Annual vaccination is the most effective means of preventing and controlling influenza epidemics, and the traditional trivalent inactivated vaccine (TIV) is by far the most widely used. Unfortunately, it has a number of limitations, the most important of which is its poor immunogenicity in younger children and the elderly, the populations at greatest risk of severe influenza. Live attenuated influenza vaccine (LAIV) has characteristics that can overcome some of these limitations. It does not have to be injected because it is administered intranasally. It is very effective in children and adolescents, among whom it prevents significantly more cases of influenza than the traditional TIV. However, its efficacy in adults has not been adequately documented, which is why it has not been licensed for use by adults by the European health authorities. LAIV is safe and well tolerated by children aged > 2 y and adults, but some concerns arisen regarding its safety in younger children and subjects with previous asthma or with recurrent wheezing. Further studies are needed to solve these problems and to evaluate the possible role of LAIV in the annual vaccination of the general population.

  9. Beta attenuation transmission system (BATS)

    Energy Technology Data Exchange (ETDEWEB)

    Hagan, R.C.; Fullbright, H.J.

    1977-01-01

    The beta attenuation transmission system (BATS) is an automated radiation gauge designed for quantitative measurement of component thickness in explosive detonators. The BATS was designed and built by Group M-1, the Nondestructive Testing Group, of the Los Alamos Scientific Laboratory to measure the areal thickness, in mg/cm/sup 2/, of a cylinder of high explosive (HE) enclosed within a plastic holder. The problem is to determine the density of the HE. A /sup 90/Sr source is collimated by a 0.25 x 1.59-mm slit, and the transmitted beta-particle flux is detected by a plastic scintillator, coupled to a photomultiplier tube. The detonator is transported through the radiation beam by a leadscrew, ballnut, stepping-motor combination. Continuous analog position data are available, derived from the output from a linear-actuated potentiometer attached to the scanner. A linear electrometer amplifies the detected signal, which is then integrated for a preselected time, to obtain the desired statistical accuracy. A microprocessor (..mu..P) is used to control the scanner position and to make the data readings at the assigned positions. The data are stored, and, at the completion of the scan, are processed into the desired format. The final answer is displayed to the operator or output to a peripheral device for permanent record. The characteristics of the radiation source, the collimator, the signal detection and conditioning, and the final results are described in detail. The scanner and the microprocessor control system are briefly outlined.

  10. Attenuation of diacylglycerol second messengers

    Energy Technology Data Exchange (ETDEWEB)

    Bishop, W.R.; Ganong, B.R.; Bell, R.M.

    1986-05-01

    Diacylglycerol(DAG) derived from phosphatidylinositol activates protein kinase C in agonist-stimulated cells. At least two pathways may contribute to the attenuation of the DAG signal: (1) phosphorylation to phosphatidic acid(PA) by DAG kinase(DGK), and (2) deacylation by DAG and monoacylglycerol lipases. A number of DAG analogs were tested as substrates and inhibitors of partially purified pig brain DGK. Two analogs were potent inhibitors in vitro, 1-monooleoylglycerol(MOG,K/sub I/ = 91 ..mu..M) and diotanoylethyleneglycol (diC/sub 8/EG, K/sub I/ = 58 ..mu..M). These compounds were tested in human platelets. DiC/sub 8/EG inhibited (70 - 100%) (/sup 32/P/sub i/) incorporation into PA in thrombin-stimulated platelets. Under these conditions the DAG signal was somewhat long-lived but was still metabolized, presumably by the lipase pathway. MOG treatment elevated DAG levels up to 4-fold in unstimulated platelets. The DAG formed was in a pool where it did not activate protein kinase C. Thrombin-stimulation of MOG-treated platelets resulted in DAG levels 10-fold higher than control platelets. This appears to be due to the inability of these platelets to metabolize agonist-linked DAG via the lipase pathway. The development of specific inhibitors of DAG kinase and DAG lipase, in conjunction with mass quantification of DAG levels as used here, will provide further insights into the regulation of DAG second messengers.

  11. Graphene-based Electronically Tuneable Microstrip Attenuator

    Directory of Open Access Journals (Sweden)

    L. Pierantoni

    2014-06-01

    Full Text Available This paper presents the design of a graphene- based electronically tuneable microstrip attenuator operating at a frequency of 5 GHz. The use of graphene as a variable resistor is discussed and the modelling of its electromagnetic properties at microwave frequencies is fully addressed. The design of the graphene-based attenuator is described. The structure integrates a patch of graphene, whose characteristics can range from being a fairly good conductor to a highly lossy material, depending on the applied voltage. By applying the proper voltage through two high-impedance bias lines, the surface resistivity of graphene can be modified, thereby changing the insertion loss of the microstrip attenuator.

  12. 棉花黄萎病菌对土壤线虫群落结构的影响%Effects of Cotton Verticillium Wilt Pathogen on Soil Nematode Community Structure

    Institute of Scientific and Technical Information of China (English)

    李晓兰; 相吉山; 刘瑜; 高志建

    2015-01-01

    In order to investigate the effect of cotton Verticillium wilt pathogens on soil ecosystem, this paper compared and studied the total numbers, amount of trophic groups and ecological indices of soil nematodes in cotton Verticillium wilt pathogens containing soil with that of control soil in Xinjiang Autonomous Region in 2013. The result indicated that a total of 42 nematode genus were identified in both pathogen infected and control areas, 36 of which were detected in the fungivores infected area, 35 were detected in the control area. The abundance of total nematodes, bacterivores and fungi ores in 0~40 cm depth soil layer were significantly lower ( P0.05)。从相对丰富度来看,黄萎病区植物寄生线虫和捕食杂食线虫的相对丰富度显著高于对照(P<0.01),食细菌线虫的相对丰富度显著低于对照( P<0.01)。从生态指数来看,黄萎病区土壤线虫的香农-威纳多样性指数( H′)、均匀度指数( J′)、营养多样性指数(TD)均显著高于对照区(P<0.05);优势度指数(λ)、通道指数(NCR)均显著低于对照区(P<0.05)。总体而言,棉花黄萎病菌会明显改变土壤线虫的群落结构,对其多样性产生显著影响。

  13. Attenuation layer for magnetostatic wave (MSW) absorbers

    Science.gov (United States)

    Glass, H. L.; Adkins, L. R.; Stearns, F. S.

    1984-09-01

    A new technique has been developed for the suppression of MSW end reflections which give rise to passband ripple. The basic idea is to provide a thin film of highly attenuating epitaxial material at the ends of a MSW delay line while preserving high quality YIG in the active region of the device. The GGG wafer preparation is a three step process which involves: (1) the growth of the attenuation layer, (2) the removal of this layer from the central region of the wafer and (3) the growth of high quality YIG on the remaining structure. Delay lines using the attenuation layer for end terminations have been evaluated experimentally and compared to devices utilizing other termination methods. The results indicate that the attenuation layer method produces ripple suppression characteristics which are the equal of those obtained with other termination techniques. The advantage of this new method lies in its suitability for large quantity fabrication requirements.

  14. Radiation-attenuated vaccine for lungworm disease

    International Nuclear Information System (INIS)

    The work done at the Indian Veternary Research Institute, Izatnagar, on the development of a vaccine for lungworm diseases is reported. Research work done includes: (1) studies on the epidemiology and the incidence of the lungworm infections, (ii) studies on the radiation-attenuated lungworm Dictyocaulus filaria vaccine, (iii) studies on other parasites using ionizing radiation, (iv) incidence of lungworm infection in sheep in Jammu and Kashmir State, (v) suitable dose of gamma radiation for attenuation, (vi) laboratory studies with radiation-attenuated D. filaria vaccine, (vii) serology of D. filaria infection, (viii) field trials with the radiation-attenuated vaccine, (ix) immune response of previously exposed lambs to vaccination, (x) comparative susceptibility of sheep and goats to infection with D. filaria, (xi) quantitative studies of D. filaria in lambs and (xii) production and supply of lungworm vaccine. (A.K.)

  15. 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).

  16. 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 by the...... periodically reinforcing beams used in lightweight building structures is analysed. The consequence of these factors in modelling flanking transmission is also discussed....

  17. First interception of Verticillium albo-atrum in Fangchenggang of Guangxi%广西防城港首次截获苜蓿黄萎病菌

    Institute of Scientific and Technical Information of China (English)

    黄胜光; 卢兆山; 邱世明; 奚国华; 陆道; 钟恒禄

    2012-01-01

    从一批进境的美国苜蓿草样品中保湿分离得到了3株与苜蓿黄萎病菌(Verticillium albo-atrum)相似的目标菌VA1、VA2、VA3.该目标菌在PDA上生长迅速,菌丝生长0.8~1.0 mm/d,2~3 d即可生成肉眼可见的菌落斑点;菌落为白色圆形,边缘规则呈圆形,菌丝较致密,气生菌丝较少,菌落中心乳白色奶冻状;培养4~5 d即后产生气生典型轮枝状分生孢子梗,7~8 d后菌落中央表面因产生休眠菌丝开始变成黑褐色至黑色,20 d后菌落的表面和背面大部分均变黑色,仍不产生微菌核和厚垣孢子.该目标菌的纯培养用V.albo-atrum特异引物Vaa1/Vaa2进行检测,PCR 扩增后得到预期330 bp的产物片段,产物序列与V.albo-atrum相应序列的相似性为100%.从而鉴定确认该目标菌为苜蓿黄萎病菌V.albo-atrum.%Three strains of the fungus, namely VA1, VA2 and VA3, were isolated from a batch of alfalfa samples, which were imported from USA and incubated under moist conditions, demonstrating the characters similar to V. Albo-atrum. The strains grew rapidly on the PDA, with the colony growing at 0.8 - 1. Omm/d. After 2-3 days, the spot colony could be seen on the PDA. In addition, the colony had a regular and rounded margin with white compact mycelium and fewer aerial mycelia. The target fungus produced typical round aerial branched co-nidiophores after 4-5 days, and then became dark brown to black along with production of resting hyphae at the centre of the colony after 7-8 days, and the color of the surface and most of the back of the colony changed to black 20 days later, but still could not produce micro-sclerotia and chlamydospores. The pure cultures of the target germ were detected by the specific primers Vaal/Vaa2. As expected, a 330 bp fragment was obtained by PCR amplification. The similarity between the product and corresponding sequence in V. Albo-atrum was 100%. Therefore, it was confirmed that the target germ was V. Albo-atrum.

  18. Maximum likelihood estimation of the attenuated ultrasound pulse

    DEFF Research Database (Denmark)

    Rasmussen, Klaus Bolding

    1994-01-01

    The attenuated ultrasound pulse is divided into two parts: a stationary basic pulse and a nonstationary attenuation pulse. A standard ARMA model is used for the basic pulse, and a nonstandard ARMA model is derived for the attenuation pulse. The maximum likelihood estimator of the attenuated ultra...

  19. Comparison of non-attenuation corrected and attenuation corrected myocardial perfusion SPE

    Directory of Open Access Journals (Sweden)

    Hasan Raza

    2016-09-01

    Conclusion: This study demonstrates that CT based attenuation corrected Tc-99mm sestamibi SPECT myocardial perfusion imaging significantly improved the specificity of the RCA territory compared with non-attenuation corrected Tc-99mm sestamibi SPECT myocardial perfusion imaging in both genders irrespective of BMI.

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

    OpenAIRE

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

    2007-01-01

    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 ...

  1. Attenuation of ear muffs in Canadian mines

    Energy Technology Data Exchange (ETDEWEB)

    Savich, M.U.

    1979-12-01

    The main characteristics of eleven commercially available ear muffs were investigated in the laboratory and analyzed by a psychophysical and a physical method. Nine ear muffs were tested in mines. The three best muffs had bands passing behind the head. The ear muff with a support strap, which improves comfort and maintains a good fit during wear, showed the best attenuation. Causes of poor attenuation are listed. None of the ear muffs tested had all the characteristics desirable in an ideal unit. Because of unsatisfactory attenuation in working conditions, it should be a mandatory requirement that workers wear both ear muffs and ear plugs if the noise level is higher than 105 dBA.

  2. Research on Nanosecond Pulse Corona Discharge Attenuation

    International Nuclear Information System (INIS)

    A line-to-plate reactor was set-up in the experimental study on the application of nanosecond pulsed corona discharge plasma technology in environmental pollution control. Investigation on the attenuation and distortion of the amplitude of the pulse wave front and the discharge image as well as the waveform along the corona wire was conducted. The results show that the wave front decreases sharply during the corona discharge along the corona wire. The higher the amplitude of the applied pulse is, the more the amplitude of the wave front decreased. The wave attenuation responds in a lower corona discharge inversely. To get a higher efficiency of the line-to-plate reactor a sharp attenuation of the corona has to be considered in practical design

  3. Finite Element Analysis of Honeycomb Impact Attenuator

    Science.gov (United States)

    Yang, Seung-Yong; Choi, Seung-Kyu; Kim, Nohyu

    To participate in Student Formula Society of Automotive Engineers (SAE) competitions, it is necessary to build an impact attenuator that would give an average deceleration not to exceed 20g when it runs into a rigid wall. Students can use numerical simulations or experimental test data to show that their car satisfies this safety requirement. A student group to study formula cars at the Korea University of Technology and Education has designed a vehicle to take part in a SAE competition, and a honeycomb structure was adopted as the impact attenuator. In this paper, finite element calculations were carried out to investigate the dynamic behavior of the honeycomb attenuator. Deceleration and deformation behaviors were studied. Effect of the yield strength was checked by comparing the numerical results. ABAQUS/Explicit finite element code was used.

  4. Live attenuated vaccines for invasive Salmonella infections.

    Science.gov (United States)

    Tennant, Sharon M; Levine, Myron M

    2015-06-19

    Salmonella enterica serovar Typhi produces significant morbidity and mortality worldwide despite the fact that there are licensed Salmonella 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: Salmonella Typhi, Salmonella Paratyphi A, Salmonella Paratyphi B (currently uncommon but may become dominant again), Salmonella Typhimurium, Salmonella Enteritidis and Salmonella 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.

  5. Research on Nanosecond Pulse Corona Discharge Attenuation

    Institute of Scientific and Technical Information of China (English)

    HE Zheng-hao; XU Huai-li; BAI Jing; YU Fu-sheng; HU Feng; LI Jin

    2007-01-01

    A line-to-plate reactor was set-up in the experimental study on the application of nanosecond pulsed corona discharge plasma technology in environmental pollution control.Investigation on the attenuation and distortion of the amplitude of the pulse wave front and the discharge image as well as the waveform along the corona wire was conducted.The results show that the wave front decreases sharply during the corona discharge along the corona wire.The higher the amplitude of the applied pulse is,the more the amplitude of the wave front decreased.The wave attenuation responds in a lower corona discharge inversely.To get a higher efficiency of the line-to-plate reactor a sharp attenuation of the corona has to be considered in practical design.

  6. Graphene-Based Waveguide Terahertz Wave Attenuator

    Science.gov (United States)

    Jian-rong, Hu; Jiu-sheng, Li; Guo-hua, Qiu

    2016-07-01

    We design an electrically controllable terahertz wave attenuator by using graphene. We show that terahertz wave can be confined and propagate on S-shaped graphene waveguide with little radiation losses, and the confined terahertz wave is further manipulated and controlled via external applied voltage bias. The simulated results show that, when chemical potential changes from 0.03 into 0.05 eV, the extinction ratio of the terahertz wave attenuator can be tuned from 1.28 to 39.42 dB. Besides the simplicity, this novel terahertz wave attenuator has advantages of small size (24 × 30 μm2), a low insertion loss, and good controllability. It has a potential application for forthcoming planar terahertz wave integrated circuit fields.

  7. Is there seismic attenuation in the mantle?

    Science.gov (United States)

    Ricard, Y.; Durand, S.; Montagner, J.-P.; Chambat, F.

    2014-02-01

    The small scale heterogeneity of the mantle is mostly due to the mixing of petrological heterogeneities by a smooth but chaotic convection and should consist in a laminated structure (marble cake) with a power spectrum S(k) varying as 1/k, where k is the wavenumber of the anomalies. This distribution of heterogeneities during convective stirring with negligible diffusion, called Batchelor regime is documented by fluid dynamic experiments and corresponds to what can be inferred from geochemistry and seismic tomography. This laminated structure imposes density, seismic velocity and potentially, anisotropic heterogeneities with similar 1/k spectra. A seismic wave of wavenumber k0 crossing such a medium is partly reflected by the heterogeneities and we show that the scattered energy is proportional to k0S(2k0). The reduction of energy for the propagating wave appears therefore equivalent to a quality factor 1/Q∝k0S(2k0). With the specific 1/k spectrum of the mantle, the resulting apparent attenuation should therefore be frequency independent. We show that the total contribution of 6-9% RMS density, velocity and anisotropy would explain the observed S and P attenuation of the mantle. Although these values are large, they are not unreasonable and we discuss how they depend on the range of frequencies over which the attenuation is explained. If such a level of heterogeneity were present, most of the attenuation of the Earth would be due to small scale scattering by laminations, not by intrinsic dissipation. Intrinsic dissipation must certainly exist but might correspond to a larger, yet unobserved Q. This provocative result would explain the very weak frequency dependence of the attenuation, and the fact that bulk attenuation seems negligible, two observations that have been difficult to explain for 50 years.

  8. Verticillium wilt of Fraxinus excelsior.

    NARCIS (Netherlands)

    Hiemstra, J.A.

    1995-01-01

    Research on ash wilt disease, a common disease of Fraxinus excelsior L. in young forest and landscape plantings in several parts of the Netherlands, is described. By means of a survey for pathogenic fungi in affected trees, inoculation and reisolation experiments it is demonstrated that the disease

  9. Ultrasound transmission attenuation tomography using energy-scaled amplitude ratios

    Science.gov (United States)

    Chen, Ting; Shin, Junseob; Huang, Lianjie

    2016-04-01

    Ultrasound attenuation of breast tumors is related to their types and pathological states, and can be used to detect and characterize breast cancer. Particularly, ultrasound scattering attenuation can infer the margin properties of breast tumors. Ultrasound attenuation tomography quantitatively reconstructs the attenuation properties of the breast. Our synthetic-aperture breast ultrasound tomography system with two parallel transducer arrays records both ultrasound reflection and transmission signals. We develop an ultrasound attenuation tomography method using ultrasound energy-scaled amplitude decays of ultrasound transmission signals and conduct ultrasound attenuation tomography using a known sound-speed model. We apply our ultrasound transmission attenuation tomography method to a breast phantom dataset, and compare the ultrasound attenuation tomography results with conventional beamforming ultrasound images obtained using reflection signals. We show that ultrasound transmission attenuation tomography complements beamforming images in identifying breast lesions.

  10. 拮抗菌S37、S44对棉花黄萎病病田土壤酶活性的影响%Effects of Antagonism Bacteria on Soil Enzyme Activities in Cotton Verticillium dahliae Field

    Institute of Scientific and Technical Information of China (English)

    王飞; 赵思峰; 李俊华; 褚贵新; 郭永盛

    2011-01-01

    The influences of different antagonism bacteria on the soil enzyme activities and cotton biomass were evaluated with a pot experiment under greenhouse conditions. Four treatments were carried out. They were health soil (CK) ,CK added with Verticillium dahliae Kleb(V), V added with antagonism bacteria S37 (VS37) and V added with antagonism bacteria S44 (VS44).The results showed that cotton biomass measured as plant fresh and dry weight was significantly inhibited with Verticillium dahliae Kleb,but significantly promoted with antagonism bacteria,so that cotton could grow normally with the treatments of VS37and VS44. The three treatments of V,VS37, VS44 could improve soil enzyme activities of catalase,alkaline phosphatase,sucrase, protease and urease. The soil polyphenol oxidase were significantly inhibited with Verticillium dahliae Kleb, but significantly promoted with antagonism bacteria. The changes of soil enzyme activities were studied from cotton seeding to bolling.The activities were higher in seeding than in bolling with antagonism bacteria. The activities of alkaline phosphatase and protease increased in seeding but decreased in bolling.%采用室内模拟试验的方法研究了在健康土壤(CK)中单独加入黄萎病菌(V)、混合加入黄萎病菌与拮抗细菌S37(VS37)或S44(VS44)后对棉花生物量和土壤酶活性的影响.研究结果表明:证实了棉花黄萎病菌显著抑制了棉花的生长发育,而拮抗菌处理能够削弱这种抑制作用,使加入棉花黄萎病菌处理的棉花与正常生长的棉花间无显著差异.V、VS37和VS44三个处理对土壤中过氧化氢酶、碱性磷酸酶、蔗糖酶、蛋白酶活性有明显的促进作用.棉花黄萎病菌显著抑制了土壤多酚氧化酶活性,但拮抗菌有显著的促进作用.本试验研究了苗期至花铃期土壤酶活性的动态变化,发现拮抗菌处理前期对土壤酶活性的促进作用高于后期.磷酸酶活性和蛋白酶活性随着生长发育

  11. 黄栌枯萎病菌拮抗细菌的分离与鉴定%Isolation and identification of an antagonistic bacterium against smoke tree wilt fungus Verticillium dahliae

    Institute of Scientific and Technical Information of China (English)

    孙妍; 于地美; 黄华毅; 王永林; 田呈明

    2015-01-01

    为了获得能有效拮抗黄栌枯萎病的大丽轮枝菌( Verticillium dahliae)和尖孢镰刀菌( Fusarium oxysporum)的生防菌株,采用系列稀释分离法和平板对峙法从盐碱地土壤中筛选拮抗细菌,基于形态特征、生理生化特性和16S rDNA序列分析鉴定菌株,并测定其无菌滤液和挥发性气体的抑菌活性。筛选结果表明,菌株C-2-3-2是一株能有效抑制黄栌枯萎病菌和尖孢镰刀菌的生防菌株,经鉴定其为枯草芽孢杆菌( Bacillus subtilis)。该菌株的无菌滤液对黄栌枯萎病菌和尖孢镰刀菌均具有明显的体外抑菌作用,且能有效抑制黄栌枯萎病菌微菌核的形成。同时,其挥发性气体也能有效抑制黄栌枯萎病菌的生长。另外,研究还发现该菌株能产生铁载体和合成氨,并产生几丁质酶、纤维素酶、蛋白酶和β-1,3-葡聚糖酶。研究结果表明菌株C-2-3-2在黄栌枯萎病生物防治中具有较好的应用潜力和较高的研究价值。%In order to isolate and characterize an antagonistic bacterial strain against Verticillium dahliae and Fusarium oxysporum, serial dilution and plate⁃confrontation methods were used for preliminary screening and selecting antagonistic bacteria from saline⁃alkali soil. Strain identification was based on morphological and physiological characteristics, and phylogenetic analysis of 16S rDNA sequence. The antagonistic effects of sterile culture filtrates and volatiles of antagonis⁃tic bacteria were determined. An antagonistic bacteria, named as C-2-3-2, was isolated and identified as Bacillus sub⁃tilis. The results indicated that sterile culture filtrate of the strain exhibited obvious in vitro inhibition against V. dahliae and F. oxysporum, and suppressed the production of microsclerotia of V. dahliae. The volatiles also effectively inhibited the mycelial growth of V. dahliae. In addition, the results indicated that C-2

  12. PathogenIdentify and Biological Characteristics of Verticillium wilt of Sunflower%向日葵黄萎病病原鉴定及其生物学特性研究

    Institute of Scientific and Technical Information of China (English)

    马立功; 张匀华; 孟庆林; 石凤梅; 刘佳; 李易初; 纪武鹏

    2011-01-01

    为更好地研究向日葵黄萎病发病规律及其有效防治方法,对向日葵黄萎病菌的形态和生物学特性进行了研究。结果表明:该病菌在梅干培养基上分生孢子透明无色,孢子梗基部为黑褐色,后期有黑色念珠状菌丝产生,未发现微菌核和厚垣孢子,证实为黄萎轮枝菌(Verticillium albo-atrumReinke et Berthold)。其菌丝生长的最佳条件为PSC,25℃,pH5~6,最适碳氮源为蔗糖和甘氨酸。产孢的最佳条件为PSC,25~30℃,pH8,最适碳氮源为D-木糖和L-组氨酸。孢子萌发的最适温度为25℃,最适pH5.9,偏酸偏碱均可促进萌发,6 h以后孢子即可萌发,12 h萌发率可达80%以上。%In order to better study the law of Verticillium wilt of sunflower and its effective control method,the morphology and biological characteristics of Verticillium albo-atrum of sunflower were studied through cultivation on culture medium PLYA.The results showed that hyaline conidia with conidiophores of dark-brown bases were produced on the medium,and black dormant mycelium appeared later with prolonged time of culturing.Microsclerotia and chlamydospores were not found.It seemed that the mycelium could grow better on PSC medium and the optimum growth conditions of the pathogen were 25℃,pH 5~6,and the optimal carbon and nitrogen sources were sucrose and glycine,respectively.For spore germination of pathogen,the optimum conditions were PSC medium,25℃and pH 8,the suitable carbon and nitrogen sources were D-xylose and L-histidine.The optimal conditions for spore germination were 25℃and pH 5.9,and it could be promoted when the culture medium was partial alkaline acidic or partial base.The spores begin to germinate after 6 hours where it cultured at 25℃ Incubator,and the germination rate would reach above 80% after 12 hours.

  13. Comparison of Secretome Extraction Methods in Verticillium dahliae%大丽轮枝菌分泌蛋白提取方法比较

    Institute of Scientific and Technical Information of China (English)

    肖红利; 桂月晶; 祁伟彦; 陈捷胤; 李蕾; 徐明; 戴小枫

    2014-01-01

    Objective]The objective of this study is to identify the high efficient method for secreted protein extraction in Verticillium dahliae, provide a technique basis for further functional characterization of V. dahliae secretome, and to construct a platform for functional verification of virulence factors and the mechanism research of V. dahliae.[Method]Secreted proteins of the high virulent V. dahliae strain VdG1 were extracted by three methods, including ultra-filtration (UF), TCA precipitation and ion-exchange (IEX), followed by LC-MS/MS analysis for protein identification. The bioinformatics softwares WoLFPSORT, SignalP, TMHMM and PHOBIUS were used to predict classical secreted proteins. The classical secreted proteins were annotated by using CAZy (carbohydrate-active enZYmes) and PHI (pathogen-host interaction) databases. In addition, motif searchs was conducted via BLASTp, such as RxLx, LysM and Cys Pattern. The extracted proteins were used to detect the biological activity and pathogenicity on susceptible cotton. [Result]By the three methods of TCA precipitation, IEX and UF, the extracted efficiency of V. dahliae secretome was 1.18, 0.96 and 0.56 mg∙L-1, respectively. The SDS-PAGE result showed that TCA and IEX extracted samples had more efficiency and purity than that of UF. The numbers of classical secreted proteins were 124, 112 and 75, respectively, of which 98, 85 and 57 were possible pathogenic factors. In addition, ion-exchange had a high extraction efficiency for small molecular weight proteins and the extracted protein could induce wilt and necrosis symptom to cotton.[Conclusion]To extract secreted proteins of V. dahliae by three methods, the lowest efficiency and purity, the minimum amount of classical secreted proteins, the fewest number of potential pathogenic factors were the UF extracted samples, and such method was quite time-consuming for large volume processing. TCA and IEX methods were fit to extract secreted proteins of V. dahliae, but TCA

  14. Switching Control for Adaptive Disturbance Attenuation

    NARCIS (Netherlands)

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

    2014-01-01

    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

  15. 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.

  16. Attenuation of PRRSV by chimera construction

    Science.gov (United States)

    Two genetically distinct infectious recombinant virus clones (pMLV, constructed from Ingelvac® PRRS MLV and pMN184, constructed from virulent strain MN184) were developed to study attenuation of contemporary PRRSV. Two reciprocal chimeric clones (pMLVORF1/MN184 and pMN184ORF1/MLV) were then constru...

  17. ULTRASONIC ATTENUATION IN MIXED STATE OF NIOBIUM

    OpenAIRE

    Dominec, J.; MÍŠek, K.

    1987-01-01

    We have investigated the attenuation of ultrasonic waves in the mixed state of niobium, where a remarkable dip appears near the lower critical field . The measurement has been performed on one sample for various orientations of the wave vector and of the principal crystallographic axes of the sample with respect to external magnetic field.

  18. Hadron attenuation at HERMES and JLab

    OpenAIRE

    Falter, T.; Cassing, W.; Gallmeister, K.; Mosel, U.

    2005-01-01

    We investigate the attenuation of hadrons in deep inelastic lepton-nucleus scattering in the kinematical regime of the HERMES and Jefferson Lab experiments. The calculation is carried out in the framework of a BUU transport model. Our results indicate a strong influence of (pre)hadronic final state interactions on the observed multiplicity ratios.

  19. 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.

  20. Influence of Verticillium dahliae Mycelium on Extracellular Proteases and Antifungal Activity of Streptomyces%大丽轮枝菌菌体对链霉菌胞外蛋白酶活性及抑菌效果的影响

    Institute of Scientific and Technical Information of China (English)

    薛磊; 薛泉宏; 赵娟; 申光辉; 唐明; 卢建军

    2012-01-01

    We investigated the antifungal mechanism of antagonistic Streptomyces on Verticillium dahliae Kleb, using pathogenic mycelium as the sole carbon source. The inducing effects of V. Dahliae on extracellular proteases and antifungal active substance synthesis were examined in four tested Streptomyces isolates in liquid cultures. V. Dahliae induced Streptomyces synthesis of extracellular protease and active antifungal substances, whereas an associated culture filtrate induced disintegration of V. Dahliae mycelium. Optimal fermentation conditions for extracellular proteases synthesized by isolate Z13 involved addition of 10 g·L-1 of fungal mycelium at 28 ℃ for 7 d. The highest extracellular protease activity of this isolate was 4.24 U. With the addition of 20 g·L-1 of fungal mycelium, V. Dahliae was 95.7% inhibited by a 5-fold dilution of a culture filtrate of isolate B49.%为研究拮抗链霉菌对棉花黄萎病原大丽轮枝菌(Verticillium dahliae Kleb.)的抑菌机理,以大丽轮枝菌菌体为唯一碳氮能源,采用液体培养法及生长速率法研究供试病原菌菌体对4株拮抗链霉菌胞外蛋白酶合成的诱导作用及抑菌活性物质产生的影响.结果表明:大丽轮枝菌菌体可以诱导供试链霉菌合成蛋白酶;诱导粗酶液对病原真菌菌丝有溶解作用;当菌体添加量为10 g·L-1,28℃培养7d时菌株Z13蛋白酶活性高达4.24 U;以大丽轮枝菌菌体为碳氮能源时供试链霉菌能产生活性较强的抑菌物质;当菌体添加量为20 g· L-1,发酵液稀释5倍时菌株B49所产抑菌活性物质的最大抑菌率达95.7%.

  1. Breath-hold CT attenuation correction for quantitative cardiac SPECT

    OpenAIRE

    Koshino, Kazuhiro; Fukushima, Kazuhito; Fukumoto, Masaji; Sasaki, Kazunari; Moriguchi, Tetsuaki; Hori, Yuki; Zeniya, Tsutomu; Nishimura, Yoshihiro; Kiso, Keisuke; Iida, Hidehiro

    2012-01-01

    Background Attenuation correction of a single photon emission computed tomography (SPECT) image is possible using computed tomography (CT)-based attenuation maps with hybrid SPECT/CT. CT attenuation maps acquired during breath holding can be misaligned with SPECT, generating artifacts in the reconstructed images. The purpose of this study was to investigate the effects of respiratory phase during breath-hold CT acquisition on attenuation correction of cardiac SPECT imaging. Methods A series o...

  2. Frequency Dependence of Attenuation Constant of Dielectric Materials

    Directory of Open Access Journals (Sweden)

    A. S. Zadgaonkar

    1975-01-01

    Full Text Available Different dielectric materials have been studied for frequency dependence of attenuation constant. The sensitive cathode ray oscillograph method has been used to evaluate to the dielectric constant and loss factor, and from these attenuation constants have been calculated. The temperature remaining constant, a regular increase has been observed in attenuation constant, at higher frequencies of electro-magnetic propagating wave.

  3. Simple Scheme for Variable High Power Laser Beam Attenuation

    OpenAIRE

    Bialkowski, Stephen E.

    1987-01-01

    A venetian style infrared attenuator placed prior to a pinhole spatial filter results in variable high‐power laser attenuation. This attenuation scheme has a wide dynamic range, results in high‐quality Gaussian beams, does not introduce beam walk‐off error, and is independent of polarization.

  4. Attenuation of microwaves by poly-disperse small spheroid particles

    Science.gov (United States)

    Zhang, Peichang; Wang, Zhenhui

    1998-08-01

    Expressions for calculating the attenuation cross sections of poly-disperse, small spheroids, whose rotatory axes are in specific status, have been derived from a universal formula for calculating the attenuation cross section of a particle of arbitrary shape. Attenuation cross sections of liquid, ice, and spongy spheroidal droplets in different size and eccentricity at different wave lengths have been computed and analyzed.

  5. Physio-Biochemical Analysis of Solanum torvum Defense Against Verticillium dahliae Infection%黄萎病菌胁迫下野生茄子托鲁巴姆防卫反应的生理生化分析

    Institute of Scientific and Technical Information of China (English)

    王忠; 杨清

    2011-01-01

    The physiological mechanisms in response to Verticillium wilt were analyzed by comparing the physiological indicators of Solanum torvum and Suqi eggplant infected with Verticillium, dahliae Kleb.The results showed that: (1) S.torvum exhibits the strong capability of egodefense and self-rehabilitation, compared with the cultivar Suqi.(2) The active oxygen scavenging system (such as: SOD, POD, CAT enzymes activity) in S.torvum was higher than in Suqi during the treatment.MDA content in S.torvum decreased after treatment, but increased in the Suqi.The results suggested that infection might activate active oxygen scavenging system it vivo,then producing certain defensive substances (such as lignin and chlorogenic acid et al.) quickly, while reducing the accumulation of MDA in the body.(3) The response time of the physiological indicators in S.torvum in response to V.dahliae was different: Activity of POD, PAL and content of soluble protein in S.torvum change rapidly within 12h, and then, change in the activity of SOD, PPO, CAT and MDA content.Eventually, S.torvum resist Verticillium.Wilt infection effectively by combinations of each enzyme.%以野生茄子托鲁巴姆(Solanum torvum Swartz)和苏崎茄(Solanum melongena L.)为主要材料,通过比较两种茄子在大丽轮枝菌(Verticillium dahliae Kleb)侵染过程中体内的生理生化指标变化,分析托鲁巴姆对黄萎病的抗性响应机制.结果表明:(1)与苏崎茄植株相比,托鲁巴姆植株表现出很强的自我防御和自我修复能力.(2)托鲁巴姆体内存在的活性氧清除系统(如SOD、POD、CAT等酶的活性)高于苏崎茄;在侵染后,托鲁巴姆体内各种酶的活性快速增加,其幅度高于苏崎茄;MDA的变化则恰恰相反.这个结果提示,黄萎病菌胁迫可能激活了托鲁巴姆体内活性氧清除系统,从而加快了某些防御物质(如木质素和抗菌物质绿原酸等)的形成,同时减缓或降低MDA等有害物质在植株体内的积累.(3)

  6. 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.

  7. Inhibition of the Cupric Complexes of Amino Acid on Microsclerotia Formation of Verticillium dahliae%几种氨基酸铜对大丽轮枝菌微菌核形成的抑制作用

    Institute of Scientific and Technical Information of China (English)

    张进霞; 袁洪水; 王士英; 韩继刚; 朱宝成

    2006-01-01

    大丽轮枝菌(Verticillium dahliae Kleb.)是引起棉花黄萎病的病原菌,它能以其休眠体一微菌核的形式在土壤中长期存活,并保持对寄主的侵染力。Bell等认为真菌的微菌核黑色素具有抵抗自然界紫外光辐射和土壤微生物侵袭的功能,不少学者认为大丽轮枝菌的微菌核黑色素与菌株致病力有关,黑色素受抑制的菌株致病力降低。外界环境,如温度、杀菌剂等影响大丽轮枝菌微菌核和微菌核色素的形成。

  8. 棉花黄萎病菌致萎毒素的分离纯化方法%Analysis on physicochemical properties of toxins produced by three verticillium dahliae strains and it's purifying method

    Institute of Scientific and Technical Information of China (English)

    陈旭升; 王祝鸣

    2002-01-01

    利用快速蛋白质液相色谱技术(Fast Protein Liquid Chromatography,FPLC),对棉花3个黄萎病菌(Verticillium dahliae)菌系外泌毒素的某些理化性质进行了分析.结果显示:黄萎病菌毒素有两个致萎峰,大分子峰Ⅰ毒蛋白致萎力较弱,致萎症状属黄斑型;而小分子峰Ⅱ毒蛋白其致萎力极强,致萎症状属青枯型.透析试验表明,可透8 000~10 000 Da的透析袋会使小分子峰Ⅱ丢失.热稳定试验表明:峰Ⅰ、峰Ⅱ毒蛋白皆可耐100℃高温水浴热煮而不发生沉淀,并保持致萎活性.根据以上研究结果,本文提出了黄萎病毒素分离纯化新方法.

  9. A primary study on effec of VAM fungi to strawberry and Verticillium wilt%VAM真菌对草莓促生、防草莓黄萎病效应初探

    Institute of Scientific and Technical Information of China (English)

    马宝红; 甄文超; 曹克强; 武玉环

    2004-01-01

    在室内条件下研究了Glomus mosseae和Glomus versiforme与草莓共生后对由大丽轮枝菌(Verticillium dahliae Kelb)引起的草莓黄萎病的抗病效果.结果表明:两种VAM真菌对草莓黄萎病均有明显的防效.与对照相比接种G.mosseae和G.versiforme的处理病情指数分别降低39.4和34.7,防效分别为66.22%和58.32%.此外,两种VAM真菌对草莓生长有明显的促进作用,接种G.mosseae和G.versiforme处理的单株株高、茎粗、根长和地上部鲜重等各项指标均明显高于对照.

  10. Highly immunogenic variant of attenuated vaccinia virus.

    Science.gov (United States)

    Yakubitskyi, S N; Kolosova, I V; Maksyutov, R A; Shchelkunov, S N

    2016-01-01

    The LIVPΔ6 strain of vaccinia virus (VACV) was created by genetic engineering on the basis of previously obtained attenuated 1421ABJCN strain by target deletion of the A35R gene encoding an inhibitor of antigen presentation by the major histocompatibility complex class II. 1421ABJCN is the LIVP strain of VACV with five inactivated virulence genes encoding hemagglutinin (A56R), γ-interferon-binding protein (B8R), thymidine kinase (J2R), complement-binding protein (C3L), and Bcl2-like inhibitor of apoptosis (N1L). The highly immunogenic LIVPΔ6 strain could be an efficient fourth-generation attenuated vaccine against smallpox and other orthopoxvirus infections. PMID:27025484

  11. Carcinoma cervix with fat attenuating skull metastases

    Institute of Scientific and Technical Information of China (English)

    Anuradha Kapali; Atmakuri Sateesh Kumar; Mukunda Malathi; S D Shamsundar

    2016-01-01

    Skeletal metastasis in carcinoma cervix occurs in about 0.8-23% of cases. These lesions are usually radiographically lytic. Very few cases of metastases to the skull have been identiifed, about 5 cases to the best of our knowledge. We present a case of adenosquamous cell carcinoma of cervix with fat attenuating skull metastases in a 38-year-old lady that is not reported till date. The lesion was lytic, expansile and with negative attenuation of -15 to -30 Hounsifeld units corresponding to fat.Metastases must be included in the differentials of scalp lesions. A history of recent onset of swelling and associated lytic areas in calvarium on contrast enhanced computed tomography with multiplicity can give a clue to metastatic nature of disease.

  12. Particle size characterization by ultrasonic attenuation spectra

    Institute of Scientific and Technical Information of China (English)

    Mingxu Su; Minghua Xue; Xiaoshu Cai; Zhitao Shang; Feng Xu

    2008-01-01

    This paper contributes to extracting information from signals of broadband ultrasonic attenuation spectrum for effective utilization in particle size characterization. The single particle scattering model and the coupled-phase model are formulated simultaneously, the relationship between particle size distribution and ultrasonic spectrum is established, and a convergence criterion for calculation is quantified. Demonsa'ation inversion by the optimum regularization factor method is carded out to yield typical numerical results for discussion. With the experimental set-up developed by the Institute of Particle and Two-Phase Flow Measurement (IPTFM) at the University of Shanghai for Science and Technology, sand sediment particle size is measured by attenuation spectrum and analyzed using the above inversion algorithm and theoretical models. To validate the proposed ultrasonic spectrum particle sizing method, results are compared with those obtained by microscopy.

  13. Attenuation of gamma radiation in concrete shields

    International Nuclear Information System (INIS)

    The attenuation characteristics of γ radiation in concrete layers considering their mechanical resistence and densities were determined. A 137Cs source was used in a 'good geometry' arrangement to eliminate the effects of the buildup factor. The ordinary and the heavy concrete were irradiated and for the latter it was used as additives iron ore and Fe2O3 pellets in various grain sizes. The detection system consisted of a 2' x 2' NaI (Tl) crystal coupled to a photomultiplier tube and the associated electronic equipment. FORTRAN programs were used for determining the absorption coefficients and the attenuation factors. These programs calculate photopeak areas eliminating all contributions due to Compton effect and background. (Author)

  14. 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. PMID:26835499

  15. Narrow terahertz attenuation signatures in Bacillus thuringiensis.

    Science.gov (United States)

    Zhang, Weidong; Brown, Elliott R; Viveros, Leamon; Burris, Kellie P; Stewart, C Neal

    2014-10-01

    Terahertz absorption signatures from culture-cultivated Bacillus thuringiensis were measured with a THz photomixing spectrometer operating from 400 to 1200 GHz. We observe two distinct signatures centered at ∼955 and 1015 GHz, and attribute them to the optically coupled particle vibrational resonance (surface phonon-polariton) of Bacillus spores. This demonstrates the potential of the THz attenuation signatures as "fingerprints" for label-free biomolecular detection. PMID:23821459

  16. The attenuation coefficients in CT: Didactic review

    International Nuclear Information System (INIS)

    The review article refers details about the derivation of the Attenuation coefficient of the CT-Number, the electron density and physical density, the effective atomic number, dual KV scanning, the performance of different scanners, furtheron the CT-numbers of intracranial structures, the attempts of characterization of tissue by CT, measurements of effective atomic number and electron density, distribution and probability of occurance of CT-numbers, and distribution of CT-numbers in space. (AJ)

  17. Bubbles attenuate elastic waves at seismic frequencies

    Science.gov (United States)

    Tisato, Nicola; Quintal, Beatriz; Chapman, Samuel; Podladchikov, Yury; Burg, Jean-Pierre

    2016-04-01

    The vertical migration of multiphase fluids in the crust can cause hazardous events such as eruptions, explosions, pollution and earthquakes. Although seismic tomography could potentially provide a detailed image of such fluid-saturated regions, the interpretation of the tomographic signals is often controversial and fails in providing a conclusive map of the subsurface saturation. Seismic tomography should be improved considering seismic wave attenuation (1/Q) and the dispersive elastic moduli which allow accounting for the energy lost by the propagating elastic wave. In particular, in saturated media a significant portion of the energy carried by the propagating wave is dissipated by the wave-induced-fluid-flow and the wave-induced-gas-exsolution-dissolution (WIGED) mechanisms. The WIGED mechanism describes how a propagating wave modifies the thermodynamic equillibrium between different fluid phases causing the exsolution and the dissolution of the gas in the liquid, which in turn causes a significant frequency dependent 1/Q and moduli dispersion. The WIGED theory was initially postulated for bubbly magmas but only recently was extended to bubbly water and experimentally demonstrated. Here we report these theory and laboratory experiments. Specifically, we present i) attenuation measurements performed by means of the Broad Band Attenuation Vessel on porous media saturated with water and different gases, and ii) numerical experiments validating the laboratory observations. Finally, we will extend the theory to fluids and to pressure-temperature conditions which are typical of phreatomagmatic and hydrocarbon domains and we will compare the propagation of seismic waves in bubble-free and bubble-bearing subsurface domains. With the present contribution we extend the knowledge about attenuation in rocks which are saturated with multiphase fluid demonstrating that the WIGED mechanism could be extremely important to image subsurface gas plumes.

  18. Phonic Attenuation due to Screen-Barriers

    OpenAIRE

    Vasile Bacria; Nicolae Herişanu

    2011-01-01

    The technique of noise decreasing admits two basic approaches: an active approach and a passive one. In the frame of passive method one can count the employment of screen-barriers. In this paper we present some considerations on sound attenuation due to screen-barriers emphasizing the elements which influence it. The elucidation of these elements is made by measurements. The obtained results can be applied in every other practical situation concerning the protection against ...

  19. Narrow terahertz attenuation signatures in Bacillus thuringiensis.

    Science.gov (United States)

    Zhang, Weidong; Brown, Elliott R; Viveros, Leamon; Burris, Kellie P; Stewart, C Neal

    2014-10-01

    Terahertz absorption signatures from culture-cultivated Bacillus thuringiensis were measured with a THz photomixing spectrometer operating from 400 to 1200 GHz. We observe two distinct signatures centered at ∼955 and 1015 GHz, and attribute them to the optically coupled particle vibrational resonance (surface phonon-polariton) of Bacillus spores. This demonstrates the potential of the THz attenuation signatures as "fingerprints" for label-free biomolecular detection.

  20. 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.

  1. Attenuated Measles Virus as a Vaccine Vector

    OpenAIRE

    Zuniga, Armando; Wang, Zili; Liniger, Matthias; Hangartner, Lars; Caballero, Michael; Pavlovic, Jovan; Wild, Peter; Viret, Jean Francois; Glueck, Reinhard; Billeter, Martin A.; Naim, Hussein Y.

    2007-01-01

    Live attenuated measles virus (MV) vaccines have an impressive record of safety, efficacy and ability to induce life-long immunity against measles infection. Using reverse genetics technology, such negative-strand RNA viruses can now be rescued from cloned DNA. This technology allows the insertion of exogenous genes encoding foreign antigens into the MV genome in such a way that they can be expressed by the MV vaccine strain, without affecting virus structure, propagation and cell targeting. ...

  2. Lg Attenuation of the Western United States

    Science.gov (United States)

    Gallegos, A. C.; Ranasinghe, N. R.; Ni, J.; Sandvol, E. A.

    2014-12-01

    Lg waveforms recorded by EarthScope's Transportable Array (TA) are used to estimate Lg Q in the Western United States (WUS). Attenuation is calculated based on Lg spectral amplitudes filtered at a narrow band from 0.5 to 1.5 Hz with a central frequency of 1 Hz. The two-station and reverse two-station techniques were used to calculate Qo values. 398 events occurring from 2005 to 2009 and ranging from magnitude 3 to magnitude 6 were used in this study. The geometric spreading term can be determined by using a three-dimensional linear fit of the amplitude ratios versus epicentral distances to two stations. The slope of this line provides the geometric spreading term we use to calculate Lg Qo values of WUS. The results show high Q regions (low attenuation) corresponding to the Colorado Plateau (CP), the Rocky Mountains (RM), the Columbia Plateau (COP), and the Sierra Nevada Mountains (SNM). Regions of low Q (high attenuation) are seen along the Snake River Plain (SRP), the Rio Grande Rift (RGR), the Cascade Mountains (CM), and in east and west of the Basin and Range (BR) where tectonic activity is more active than the central part of the BR. A positive correlation between high heat flow, recent tectonic activity and Q was observed. Areas with low heat flow, thin sediment cover, and no recent tectonic activity were observed to have consistently high Q. These new models use two-station and reversed two-station methods and provide a comparison with previous studies and better constrain regions with high attenuation. This increase in detail can improve high frequency ground motion predictions of future large earthquakes for more accurate hazard assessment and improve overall understanding of the structure and assemblage of the WUS.

  3. The Violent Content in Attenuated Psychotic Symptoms.

    Science.gov (United States)

    Marshall, Catherine; Deighton, Stephanie; Cadenhead, Kristin S; Cannon, Tyrone D; Cornblatt, Barbara A; McGlashan, Thomas H; Perkins, Diana O; Seidman, Larry J; Tsuang, Ming T; Walker, Elaine F; Woods, Scott W; Bearden, Carrie E; Mathalon, Daniel; Addington, Jean

    2016-08-30

    The relationship between psychosis and violence has typically focused on factors likely to predict who will commit violent acts. One unexplored area is violence in the content of subthreshold positive symptoms. The current aim was to conduct an exploratory analysis of violent content in the attenuated psychotic symptoms (APS) of those at clinical high risk of psychosis (CHR) who met criteria for attenuated psychotic symptom syndrome (APSS). The APS of 442 CHR individuals, determined by the Structured Interview for Prodromal Syndromes, were described in comprehensive vignettes. The content of these symptoms were coded using the Content of Attenuated Positive Symptoms Codebook. Other measures included clinical symptoms, functioning, beliefs and trauma. Individuals with violent content had significantly higher APS, greater negative beliefs about the self and others, and increased bullying. The same findings and higher ratings on anxiety symptoms were present when participants with self-directed violence were compared to participants with no violent content. Individuals reporting violent content differ in their clinical presentation compared to those who do not experience violent content. Adverse life events, like bullying, may impact the presence of violent content in APS symptoms. Future studies should explore violent content in relation to actual behavior. PMID:27259137

  4. Natural Biological Attenuation of Benzene in Groundwater

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Benzene has been found in subsurface unsaturated soil and groundwater beneath a petro-chemical plant. Although the groundwater contained several mg/L of benzene in the area immediately beneath the source, benzene was not detected in monitoring wells approximately 800m down stream. All kinds of physical processes such as adsorption and advection/dispersion are considered to account for the observed attenuation. The results indicated that the attenuation was primarily due to natural biological processes occurring within the aquifer. The evidence for the natural bioremediation of benzene from the groundwater included: (1) analysis of groundwater chemistry, (2) laboratory studies demonstrating benzene biodegradation in aquifer samples, and (3) computer simulations examining benzene transport. Laboratory experiments indicated that for conditions similar to those in the plume, the aerobic degradation of benzene by the naturally occurring microorganisms in the polluted groundwater samples was quite rapid with a half-life time of from 5 to 15 days. In situ analyses indicated the level of dissolved oxygen in the groundwater was over 2mg/L. Thus, oxygen should not limit the biodegradation. In fact, the benzene was also shown to degrade under anaerobic conditions. The results from the modeling simulations indicate that biodegradation is the dominant process influencing attenuation of the benzene.

  5. Waves in fragmented geomaterials with impact attenuation

    Science.gov (United States)

    Dyskin, Arcady; Pasternak, Elena

    2016-04-01

    Attenuation of waves in geomaterials, such as seismic waves is usually attributed to energy dissipation due to the presence of viscous fluid and/or viscous cement between the constituents. In fragmented geomaterials such as blocky rock mass there is another possible source of energy dissipation - impacting between the fragments. This can be characterised by the coefficient of restitution, which is the ratio between the rotational velocities after and before the impact. In particular, this manifests itself in the process of mutual rotations of the fragments/blocks, whereby in the process of oscillation different ends of the contacting faces of the fragments are impacting. During the rotational oscillations the energy dissipation is concentrated in the neutral position that is the one in which the relative rotation between two fragments is zero. We show that in a simple system of two fragments this dissipation is equivalent, in a long run, to the presence of viscous damper between the fragments (the Voigt model of visco-elasticity). Generalisation of this concept to the material consisting of many fragments leads to a Voigt model of wave propagation where the attenuation coefficient is proportional to the logarithm of restitution coefficient. The waves in such a medium show slight dispersion caused by damping and strong dependence of the attenuation on the wave frequency.

  6. 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.

  7. Soil mass attenuation coefficient: Analysis and evaluation

    International Nuclear Information System (INIS)

    Highlights: • Experimental mass attenuation coefficient is affected by sample size. • Sample thickness larger than 9 cm presents the best results for 137Cs. • Sample thickness smaller than 5 cm presents the best results for 241Am. - Abstract: The mass attenuation coefficient (μ) is an important parameter to characterize the penetration and interaction of gamma-rays in the soil. Accurate determinations of μ are important to obtain representative values of soil physical properties by gamma-ray attenuation technique. In this study, the effect of collimator size (2–4 mm diameters) and absorber thickness (2–15 cm) on the experimental μ values of water and soils with different textures were investigated for 59.54 keV (241Am) and 661.1 keV (137Cs) gamma-ray sources. Theoretical results were calculated using the program XCOM. Experimental results were compared with theoretical ones showing a good correlation between methods. It was observed that for the 137Cs the best agreements between theoretical and experimental μ were obtained for sample thickness ⩾10 cm while for the 241Am were those obtained for thickness <5 cm for small collimators

  8. 棉花黄萎病真菌Verticillium dahliae木聚糖酶基因的克隆、表达和酶学性质分析%Molecular cloning and heterologous expression of a new xylanase gene from Verticillium dahliae

    Institute of Scientific and Technical Information of China (English)

    张桂敏; 饶犇; 叶戋; 马立新; 张先恩

    2008-01-01

    [目的]从棉花黄萎病真菌Verticillium dahliae中克隆木聚糖酶基因,并在毕赤酵母中进行异源表达,研究酶学性质.[方法]通过多序列比对设计简并引物,扩增出真菌V. dahliae木聚糖酶基因片段,再采用基因组步行PCR技术获得全长木聚糖酶基因序列.经BLAST比对并结合GT-AG原则分析,该基因含有一个大小为63 bp的内含子,利用DpnI介导的缺失方法对含内含子的全长木聚糖酶基因进行剪接,获得该基因的全长cDNA.将克隆到的cDNA在毕赤酵母GS115进行了表达,重组酶经纯化后进行酶学性质分析.[结果]BLAST比对显示,该cDNA推测的氨基酸序列和已知木聚糖酶的最高一致性为72%.测得该酶最适反应温度为45℃,最适反应pH值为6,在pH5-9维持50%以上的活性,对山毛榉材木聚糖具有最好的水解效果.Mg2+和Ca2+对酶有激活作用,分别提高了33.7%和16.6%,EDTA,β-巯基乙醇和NaN3对酶的活性基本没有影响,Tween-80和DMSO使酶活性提高了28.4%和12.8%.[结论]本文从引起棉花黄萎病的真菌V. dahliae中克隆到的木聚糖酶基因是在GenBank上登录的第一个来自棉花黄萎病真菌的木聚糖酶基因序列.本文所用的克隆方法可以高效的从植物病原真菌和白腐真菌克隆只含一个内含子的11家族的新木聚糖酶基因,避免了摸索原始菌株酶表达诱导条件,检测酶的活性等繁琐的操作.酶学性质分析显示该酶在低聚木糖的制备,面包改良上有潜在的应用价值.

  9. 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.

  10. 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...

  11. Effects of Herba Asari Extracts on Eggplant Verticillium dahliae, Its Growth and Resistance Physiological Indexes%细辛提取物对茄子黄萎病及茄子生长与抗性生理指标的影响

    Institute of Scientific and Technical Information of China (English)

    周宝利; 姜春云; 陈志霞; 李腾飞; 宋岩

    2012-01-01

    以茄子黄萎病为研究对象,采用不同浓度的细辛(Herba asari)提取物灌根处理茄子幼苗,研究其对茄子黄萎病的抗性、植株生长状况及保护酶活性的影响.结果表明:与清水对照相比,施用不同浓度的细辛提取物均降低了茄子黄萎病的发病率及病情指数,作用强度随着细辛提取物浓度的增加先增强后略有下降,预防处理明显比治疗处理效果好,4g·L-1细辛提取物预防处理的防治效果可达86.26%;不同浓度的细辛提取物对茄子幼苗的株高、茎粗、鲜质量、相对电导率、叶绿素含量、根系活力、苯丙氨酸解氨酶(PAL)活性、过氧化物酶(POD)活性和超氧化物歧化酶(SOD)活性均表现为促进作用,最佳处理浓度为4 g·L-1.%The effects of different Herba asari extracts concentrations on eggplant disease resistance to Verticillium dahliae, seedling growth and activities of defense enzymes were investigated by inoculating Verticillium dahliae. The results showed that the disease incidence and disease index of eggplant Verticillium dahliae were both decreased after applying Herba asari extracts of different concentrations compared with the contrast. With the increase of concentration, eggplant Verticillium dahliae resistance increased firstly and then slightly decreased, and yet the preventive treatment effect was better than cure treatment. The best controlling effect ( 86.26% ) was found when the concentration reached 4 g · L-1 . Eggplant stem height, stem diameter, fresh weight, relativee electricity conductivity, chlorophyll content, root system vigor and activities of defense enzymes ( PAL, POD and SOD ) were all promoted by different concentrations of Herba asari extracts. The concentration of 4 g · L-1 could gain the best effect.

  12. 茄子白绢病、猝倒病、根腐病、黄萎病和枯萎病的识别与防治%ldentification and Control Methods of Eggplant Southern Blight, Damp-ing-off, Root Rot, Verticil-lium Wilt and Fusarium Wilt

    Institute of Scientific and Technical Information of China (English)

    高焕; 郑丹丹

    2012-01-01

    介绍了茄子白绢病、猝倒病、根腐病、黄萎病和枯萎病的危害症状、发病特点,并从农业措施、化学防治等方面总结了各病害的综合防治方法。%The symptom and disease characteristics of eggplant southern blight, damping-off, root rot, verticillium wilt and fusarium wilt were introduced. Then the integrated control methods were put forward, which contained measures of agricultural control, chemical control and so on.

  13. 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.

  14. 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.

  15. Vinpocetine attenuates lipid accumulation and atherosclerosis formation

    International Nuclear Information System (INIS)

    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

  16. Towards a Global Upper Mantle Attenuation Model

    Science.gov (United States)

    Karaoglu, Haydar; Romanowicz, Barbara

    2015-04-01

    Global anelastic tomography is crucial for addressing the nature of heterogeneity in the Earth's interior. The intrinsic attenuation manifests itself through dispersion and amplitude decay. These are contaminated by elastic effects such as (de)focusing and scattering. Therefore, mapping anelasticity accurately requires separation of elastic effects from the anelastic ones. To achieve this, a possible approach is to try and first predict elastic effects through the computation of seismic waveforms in a high resolution 3D elastic model, which can now be achieved accurately using numerical wavefield computations. Building upon the recent construction of such a whole mantle elastic and radially anisotropic shear velocity model (SEMUCB_WM1, French and Romanowicz, 2014), which will be used as starting model, our goal is to develop a higher resolution 3D attenuation model of the upper mantle based on full waveform inversion. As in the development of SEMUCB_WM1, forward modeling will be performed using the spectral element method, while the inverse problem will be treated approximately, using normal mode asymptotics. Both fundamental and overtone time domain long period waveforms (T>60s) will be used from a dataset of over 200 events observed at several hundred stations globally. Here we present preliminary results of synthetic tests, exploring different iterative inversion strategies.

  17. Live attenuated influenza vaccine--a review.

    Science.gov (United States)

    Gasparini, R; Amicizia, D; Lai, P L; Panatto, D

    2011-09-01

    Owing to the variability of influenza viruses, vaccine composition needs to be up-dated annually. As many variables can influence their efficacy, vaccines are still considered "sub-optimal". Many studies have been carried out in recent years to improve vaccines. In particular, researchers and vaccine-producing corporations have focused on developing a live vaccine. Among the candidate vaccines, the strain developed by Maassab has recently been licensed in the USA and Europe, after extensive investigation. This vaccine is safe and well tolerated, and has shown very good genetic stability. Although vaccine recipients are able to spread the virus, transmission to close contacts is practically non-existent. Studies on cold-adapted attenuated influenza vaccines have demonstrated that such vaccines are effective, and sometimes more effective than inactivated influenza vaccines. Cold-adapted attenuated influenza vaccines therefore appear to be an important weapon against influenza. However, a more widespread use of these vaccines is to be recommended, especially in children, as the more acceptable way of administration can favour parental compliance.

  18. 河北省棉花黄萎病菌致病性与ISSR遗传分化%Pathogenicity and ISSR Genetic Differentiation of Verticillium dahliae Isolates from Cotton Growing Areas of Hebei Province

    Institute of Scientific and Technical Information of China (English)

    王国宁; 赵贵元; 岳晓伟; 李志坤; 张艳; 张桂寅; 吴立强; 王省芬; 马峙英

    2012-01-01

    Fifty-two Verticillium dahliae isolates were recovered from 17 main cotton growing counties of Hebei Province. Cul-turing characteristics, pathogenicity and genetic variation based on ISSR marker were studied. According to culturing characteristics on PDA medium, the tested isolates could be classified into sclerotia type, filamentous type and intermediate type. Scleroti-a type isolates which accounted for 51.9% were the most, followed by filamentous type (38.5%) and intermediate type (9.6%). In the growth chamber where the light, temperature and humidity were controlled automatically, the pathogenicity of 52 isolates was evaluated on seven cotton varieties with different disease resistance to Verticillium wilt. The results indicated that the isolates could be divided into three pathogenic types, i.e. strong (type Ⅰ ), mild (type Ⅱ) and weak (type Ⅲ), which accounted for 51.9%, 21.2% and 26.9% of the total, respectively. The nondefoliated isolate that had stronger pathogenicity than defoliated isolates was found. Generally, sclerotia- and intermediate- type isolates had strong or moderate pathogenicity, while filamentous type isolates had a widely pathogenic diversification. Cluster analysis based on disease index showed that 52 isolates had obvious pathogenicity differentiation that was not obviously related to their geographic origin. A total of 136 ISSR markers were amplified, and 80 markers that accounted for 58.8% of the total belonged to polymorphic markers. ISSR analysis indicated that the genetic variation of 52 isolates was small and related to geographic region.%从河北省17个主要植棉县采集棉花黄萎病株,分离获得52个黄萎病菌单孢菌系,对其培养特性、致病性和ISSR(Inter-simple sequence repeat)遗传分化进行了研究.菌系培养性状研究表明,在采集的52个菌系中,菌核型菌系最多,其次是菌丝型,最少的是中间型,3种类型菌系分别占总菌系的51.9%,38.5%和9.6%.利用7

  19. 棉花黄萎病拮抗细菌HMB-1005鉴定及定殖%Studies on identification and colonization of antagonistic bacteria HMB-1005 to cotton Verticillium dahliae

    Institute of Scientific and Technical Information of China (English)

    郭慧娟; 李术娜; 李红亚; 王全; 王树香; 王伟; 朱宝成

    2011-01-01

    In this study, determination of antagonistic activity was done to the strain HMB-1005 from the cotton fields with the Verticillium dahliae strains as the instructions, characteristics of strain HMB-1005 equates well with Bacillus amyloliquefaciens at the level of species in morphological, 19 physiological biochemical items and 16S rDNA sequence. This test required sterile soil and non-sterile soil in two soil samples, this test need two soil samples of three different treatment that was: The antagonistic bacterium bacillus soaking liquid, all mixed soil and part of soil for plants mixed. The purpose of this paper was to study antagonistic bacteria HMB-1005 in the soil and in the colonization of cotton roots and rhizosphere colonization of the situation. The results showed that antagonistic bacteria HMB-1005 in non-sterilized soil and sterilized soil colonization could reproduce, and the quantity achieved 106cfu/g. Through revovery bacteria of cotton roots, confirmed the antagonistic bacteria in the HMB-1005 designated cotton root colonization, number of 103cfu/g. This experiment indicated the antibacterial number in antiseptic was higher than the non-antiseptic earth, and the difference during three processing modes was not obviously. Considered the various factor, minded that the first method would be better.%以大丽轮枝菌(Verticillium dahliae)为指示菌,对从棉田土壤中已经分离筛选到的细菌HMB-1005进行形态、19项生理生化特征及16S rDNA试验,结果表明,HMB-1005为解淀粉芽孢杆菌(Bacillus amyloliquefaciens);通过灭菌土和非灭菌土进行盆栽试验,拮抗菌HMB-1005芽孢液浸种、土壤全部混菌和部分混菌3种处理,经过5个月的盆栽试验表明,拮抗细菌HMB-1005能够在灭菌土和非灭菌土中定殖,且定殖数量达106cfu/g 土左右,并仍能保持较高的抑菌活性.通过对棉苗根内细菌的分离,证实拮抗细菌HMB-1005能在棉花根内定殖,数量达到103cfu/g.实验结果显

  20. 拮抗性链霉菌对大丽轮枝菌微菌核形成与萌发的影响%Inhibition of antagonistic Streptomyces spp. on microsclerotia formation and germination of Verticillium dahliae

    Institute of Scientific and Technical Information of China (English)

    薛磊; 王建涛; 刘相春; 薛泉宏; 申光辉; 赵娟

    2012-01-01

    The antifungal mechanism of antagonistic Streptomyces spp. against Verticillium dahliae Kleb. was studied. The inhibitory effect of six Streptomyces strains culture filtrate on mycelium growth, micro- sclerotia formation and germination of V. dahliae were tested by means of the methods of mycelium growth rate and microsclerotia germination. The results showed that mycelium growth of V. dahlia was inhibited by culture filtrates of Streptomyces. Culture filtrate of Streptomyces B49 strong inhibited myeelium growth of V. dahlia; the inhibition rate of 5-fold-dilution culture filtrate against mycelium growth of V. dahliae was 69.7% at 14 d. Microsclerotia formation of V. dahlia was inhibited by culture filtrate of Streptomy- ces. 5-fold-dilution culture filtrates of Streptomyces isolates B49, D184 and Act12 displayed completely inhibitory effects on microsclerotia formation of V. dahlia with 100% of inhibitory rate. Mutant strain of V. dahliae which obtained from these three Streptomyces culture filtrate treatments did not produce micro- sclerotia; they were not reversed to wild type on PDA medium after five times subculture. Microsclerotia germination of V. dahliae was also inhibited by culture filtrate of Streptomyces, the germination rate of iso- late D184 5-fold-dilution culture filtrate was 38.3% at 168 h.%为探索拮抗性链霉菌对棉花黄萎病病原大丽轮枝菌Verticillium dahliae Kleb.的抑菌机制,采用菌丝生长速率法、微菌核萌发法研究了6株拮抗链霉菌无菌发酵滤液对大丽轮枝菌生长、微菌核形成与萌发的影响。链霉菌无菌发酵滤液对大丽轮枝菌菌落生长、菌核形成和微菌核萌发有明显抑制作用。其中菌株B49的抑菌效果最好,5倍稀释发酵液培养14天时对菌落生长的抑菌率达69.7%;菌株B49、D184和Act12的5倍稀释发酵液对微菌核形成的抑制率达100%;将经B49、D184和Act12发酵液处理后丧失形成微菌核能力的大丽轮枝菌菌株转接

  1. Applying Echoes Mean Frequency Shift for Attenuation Imaging in Tissue

    Science.gov (United States)

    Litniewski, J.; Klimonda, Z.; Nowicki, A.

    The purpose of this study was to develop the attenuation parametric imaging technique and to apply it for in vivo characterization of tissue. Local attenuation coefficient was determined by evaluating the frequency downshift that encounters the amplitude spectrum of the interrogating ultrasonic pulse during propagation in the absorbing tissue. Operation and accuracy of the processing methods were verified by assessing the size-independent region of interest (ROI) for attenuation determination and calculating the attenuation coefficient distribution for experimentally recorded tissue-phantom scattered waveforms. The Siemens Antares scanner equipped with Ultrasound Research Interface unit allowing for direct radiofrequency (RF) signals recording was used for B-scan imaging of the tissue- mimicking phantom in vitro and liver in vivo. RF data were processed to determine attenuation coefficient along the B-scan lines. Also, the preliminary studies of backscattered signals from skin recorded using a skin scanner were performed to calculate parametric-attenuation images.

  2. A wideband IM3 cancellation technique for CMOS attenuators

    NARCIS (Netherlands)

    Cheng, W.; Oude Alink, M.S.; Annema, A.J.; Wienk, G.J.M.; Nauta, B.

    2012-01-01

    A highly linear P attenuator system using a wideband IM3 cancellation technique is presented that provides 4 discrete attenuation levels with 6dB spacing for DC-5GHz. For the whole band, S11<-14dB, attenuation flatness<1.6dB, +10dBm input P1dB and +26dBm IIP3 are achieved. For the TV band (0.1Gz-1.2

  3. Screening and Identification of Antagonistic Bacterium Strain 7-4 against Verticillium dahliae%大丽轮枝菌拮抗细菌多粘芽孢杆菌7-4菌株的筛选与鉴定

    Institute of Scientific and Technical Information of China (English)

    王笑颖; 孟成生; 雷白时

    2011-01-01

    为筛选对棉花黄萎病病原茵大丽轮枝菌(Verticillium dahliae)具有拮抗作用的芽孢细菌,采用改良的琼脂平板扩散法,通过初筛从各地的土样中分离到84株拮抗细菌菌株,再对其进行复筛,得到1株具有较强抑菌活性的拮抗细菌7-4菌株,并对该菌株进行了形态特征观察和生理生化鉴定,初步判断其为多粘芽孢杆菌(Bacillus polvmyxa).%In order to obtain antagonistic bacteria against Verticillium dahliae, 84 antagonistic strains were isolated from the soil in different areas and screened by improved agar plate diffusion method. The antagonistic activity against V. dahliae of strains were tested via secondary screening. As a result, a strain called 7-4 which had strong inhibition capability against V.dahliae was obtained. According to morphological and culture characters, physiological and biochemical experiments,the strain 7-4 was preliminarily identified as Bacillus polymyxa.

  4. 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

  5. Attenuation characteristics of ground motions in northern China

    Institute of Scientific and Technical Information of China (English)

    黄玉龙; 赵兴权; 罗奇峰

    2002-01-01

    Four recently developed attenuation models are calibrated by using a very limited amount of strong motion data recorded in China. The research shows that the attenuation characteristics of the earthquake shaking in northern China are similar to those in the western US. The supporting evidence includes Q factors, preliminary results of kappa values, stress drop,shear wave velocity profile in the shallow earth crust, areas enclosed by the isoseismals of Modified Mercalli Intensity V. From these comparisons of different attenuation models, it is recommended that the Crouse and McGuire spectral attenuation model could possibly be used for northern China.

  6. Importance of Attenuation Correction (AC for Small Animal PET Imaging

    Directory of Open Access Journals (Sweden)

    Henrik H. El Ali

    2012-10-01

    Full Text Available The purpose of this study was to investigate whether a correction for annihilation photon attenuation in small objects such as mice is necessary. The attenuation recovery for specific organs and subcutaneous tumors was investigated. A comparison between different attenuation correction methods was performed. Methods: Ten NMRI nude mice with subcutaneous implantation of human breast cancer cells (MCF-7 were scanned consecutively in small animal PET and CT scanners (MicroPETTM Focus 120 and ImTek’s MicroCATTM II. CT-based AC, PET-based AC and uniform AC methods were compared. Results: The activity concentration in the same organ with and without AC revealed an overall attenuation recovery of 9–21% for MAP reconstructed images, i.e., SUV without AC could underestimate the true activity at this level. For subcutaneous tumors, the attenuation was 13 ± 4% (9–17%, for kidneys 20 ± 1% (19–21%, and for bladder 18 ± 3% (15–21%. The FBP reconstructed images showed almost the same attenuation levels as the MAP reconstructed images for all organs. Conclusions: The annihilation photons are suffering attenuation even in small subjects. Both PET-based and CT-based are adequate as AC methods. The amplitude of the AC recovery could be overestimated using the uniform map. Therefore, application of a global attenuation factor on PET data might not be accurate for attenuation correction.

  7. [Usefulness of attenuation correction with transmission source in myocardial SPECT].

    Science.gov (United States)

    Murakawa, Keizo; Katafuchi, Tetsuro; Nishimura, Yoshihiro; Enomoto, Naoyuki; Sago, Masayoshi; Oka, Hisashi

    2006-01-20

    Attenuation correction in SPECT has been used for uniformly absorptive objects like the head. On the other hand, it has seldom been applied to nonuniform absorptive objects like the heart and surrounding lungs because of the difficulty and inaccuracy of data processing. However, since attenuation correction using a transmission source recently became practical, we were able to apply this method to a nonuniform absorptive object. Therefore, we evaluated the usefulness of this attenuation correction system with a transmission source in myocardial SPECT. The dose linearity, defect/normal ratio using a myocardial phantom, and myocardial count distribution in clinical cases was examined with and without the attenuation correction system. We found that all data processed with attenuation correction were better than those without attenuation correction. For example, in myocardial count distribution, while there was a difference between men and women without attenuation correction, which was considered to be caused by differences in body shape, after processing with attenuation correction, myocardial count distribution was almost the same in all cases. In conclusion, these results suggested that attenuation correction with a transmission source was useful in myocardial SPECT.

  8. 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

  9. 水茄泛素结合酶E2基因StUBCc的克隆及黄萎病菌诱导表达分析%Cloning and Expression Analysis Induced by Verticillium Wilt Fungus of Ubiquitin-conjugating Enzyme Gene StUBCc from Solanum torvum

    Institute of Scientific and Technical Information of China (English)

    刘炎霖; 陈钰辉; 刘富中; 张映; 连勇

    2015-01-01

    以茄子近缘野生种水茄(Solanum torvum Swartz)幼苗根部为试材,并以黄萎病菌(大丽轮枝菌,Verticillium dahliae Kleb)处理的水茄的抑制差减文库中差异表达的EST片段F290为基础,利用RACE技术,获得一个756 bp的cDNA全长序列.经生物信息学分析发现该序列为泛素结合酶E2-2(UBC2)载体蛋白同源基因,命名为StUBC,GenBank登录号为KP330492.StUBCc基因编码区共459bp,编码152个氨基酸,该蛋白分子量为63.0925kD,等电点为5.13.采用MEGA5软件对StUBCc和其他同源蛋白的氨基酸序列比对,结果表明其与葡萄的同源蛋白一致性最高,达99%,有很高的功能区段保守性.采用荧光定量PCR对黄萎病菌侵染不同时间的水茄幼苗根部StUBCc基因的表达量进行测定,发现在侵染6h后,表达量最高,为对照(无菌水处理)的6.79倍.%An EST F290 was from suppression subtractive hybridization library made from pathogen treated roots of the seedling roots of verticillium wilt (Verticillium dahliae Kleb) resistant Solanum torvum Swartz.A full length cDNA (756 bp) was obtained using rapid amplification ofcDNA ends (RACE) technology,which encoded the ubiquitin-conjugating enzyme E2-2 (UBC2) family gene and was designated as StUBCc.GenBank number is KP330492.The putative protein contains of 152 amino acids with a molecular weight of 63.0925 kD and a theoretical pI of 5.13.Multiple sequence alignment of the amino acid sequence between StUBCc and other homologs from several plants were analyzed by MEGA 5 and shows that the StUBCc has higher identity with UBC genes from Vitis vinifera.The identities is 99% with a deduced amino acid sequence of highly conserved functional domain.The expressions of the isolated StUBCc in the roots of S.torvum seedlings treated by verticillium wilt fungus as well as sterile water at different time points was studied by using quantitative RT-PCR.The results indicated that the expression of the newly isolated StUBCc gene was

  10. Definition of Genetically Distinct Attenuation Mechanisms in Naturally Virulence-Attenuated Listeria monocytogenes by Comparative Cell Culture and Molecular Characterization

    OpenAIRE

    Roberts, Angela; Chan, Yvonne; Wiedmann, Martin

    2005-01-01

    Listeria monocytogenes is a foodborne pathogen able to cause serious disease in humans and animals. Not all isolates are equally pathogenic, however, and several isolates have been characterized as naturally virulence attenuated. We sought to identify the genetic basis of natural virulence attenuation using cell culture assays and molecular techniques. By comparing the phenotypes of naturally virulence-attenuated isolates to those of defined virulence gene mutants in plaque, cytotoxicity, and...

  11. Turbulence attenuation by large neutrally buoyant particles

    CERN Document Server

    Cisse, Mamadou; Gibert, Mathieu; Bodenschatz, Eberhard; Bec, Jeremie

    2015-01-01

    Turbulence modulation by inertial-range-size, neutrally-buoyant particles is investigated experimentally in a von K\\'arm\\'an flow. Increasing the particle volume fraction $\\Phi_\\mathrm{v}$, maintaining constant impellers Reynolds number attenuates the fluid turbulence. The inertial-range energy transfer rate decreases as $\\propto\\Phi_\\mathrm{v}^{2/3}$, suggesting that only particles located on a surface affect the flow. Small-scale turbulent properties, such as structure functions or acceleration distribution, are unchanged. Finally, measurements hint at the existence of a transition between two different regimes occurring when the average distance between large particles is of the order of the thickness of their boundary layers.

  12. Attenuation of neutrons through ducts and labyrinths

    CERN Document Server

    Mauro, Egidio

    2009-01-01

    Monte Carlo simulations have been performed for the attenuation of neutron radiation produced at proton accelerators through ducts and labyrinths of various design, and the results are compared with the predictions made by analytical expressions available in the literature. The results show that the so-called universal transmission curves are an appropriate and simple tool applicable in many situations, when the radiation source is not in direct view of the duct mouth. This is not the case for point sources located in front of the duct. The simulations showed that it is not possible to apply the same models because the transmission factor is strongly dependent on the cross-sectional area of the duct. A universal expression has been derived to estimate the neutron transmission through a straight duct of length d and cross-sectional area A in direct view of the source, which only depends on A and on a small set of numerical coefficients.

  13. Attenuation of Shocks through Porous Media

    Science.gov (United States)

    Lind, Charles A.; Cybyk, Bohdan Z.; Boris, Jay P.

    1998-11-01

    Structures designed to mitigate the effects of blast and shock waves are important for both accidental and controlled explosions. The net effect of these mitigating structures is to reduce the strength of the transmitted shock thereby reducing the dynamic pressure loading on nearby objects. In the present study, the attenuation of planar blast and shock waves by passage through structured media is numerically studied with the FAST3D model. The FAST3D model is a state-of-the-art, portable, three-dimensional computational fluid dynamics model based on Flux-Corrected Transport and uses the Virtual Cell Embedding algorithm for simulating complex geometries. The effects of media placement, spacing, orientation, and area blockage are parametrically studied to enhance the understanding of the complex processes involved and to determine ways to minimize the adverse effects of these blast waves.

  14. Core disgust is attenuated by ingroup relations.

    Science.gov (United States)

    Reicher, Stephen D; Templeton, Anne; Neville, Fergus; Ferrari, Lucienne; Drury, John

    2016-03-01

    We present the first experimental evidence to our knowledge that ingroup relations attenuate core disgust and that this helps explain the ability of groups to coact. In study 1, 45 student participants smelled a sweaty t-shirt bearing the logo of another university, with either their student identity (ingroup condition), their specific university identity (outgroup condition), or their personal identity (interpersonal condition) made salient. Self-reported disgust was lower in the ingroup condition than in the other conditions, and disgust mediated the relationship between condition and willingness to interact with target. In study 2, 90 student participants smelled a sweaty target t-shirt bearing either the logo of their own university, another university, or no logo, with either their student identity or their specific university identity made salient. Walking time to wash hands and pumps of soap indicated that disgust was lower where the relationship between participant and target was ingroup rather than outgroup or ambivalent (no logo). PMID:26903640

  15. 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

  16. Attenuation of ultrasonic waves in rolled metals

    Science.gov (United States)

    Yang, Liyong; Turner, Joseph A.

    2004-12-01

    Scattering of ultrasonic waves in polycrystals with texture is studied in this article. The attenuations of the three wave modes are determined as a function of dimensionless frequency and propagation direction, respectively, for given orientation distribution coefficients (ODCs). The calculation is done in the case of a statistically orthorhombic sample made up of cubic crystallites. The wave propagation and scattering model is formulated by the Dyson equation using an anisotropic Green's function approach. Within the limits of the first-order smoothing approximation, the Dyson equation is solved in the spatial Fourier transform domain. The results presented are shown to be directional dependent, frequency dependent, and especially dependent on the texture coefficients (ODCs) for the quasilongitudinal and two quasishear waves. The theoretical results presented may be used to improve the understanding of the microstructure during recrystallization processes. .

  17. Attenuation of species abundance distributions by sampling.

    Science.gov (United States)

    Shimadzu, Hideyasu; Darnell, Ross

    2015-04-01

    Quantifying biodiversity aspects such as species presence/ absence, richness and abundance is an important challenge to answer scientific and resource management questions. In practice, biodiversity can only be assessed from biological material taken by surveys, a difficult task given limited time and resources. A type of random sampling, or often called sub-sampling, is a commonly used technique to reduce the amount of time and effort for investigating large quantities of biological samples. However, it is not immediately clear how (sub-)sampling affects the estimate of biodiversity aspects from a quantitative perspective. This paper specifies the effect of (sub-)sampling as attenuation of the species abundance distribution (SAD), and articulates how the sampling bias is induced to the SAD by random sampling. The framework presented also reveals some confusion in previous theoretical studies. PMID:26064626

  18. A miniaturized reconfigurable broadband attenuator based on RF MEMS switches

    Science.gov (United States)

    Guo, Xin; Gong, Zhuhao; Zhong, Qi; Liang, Xiaotong; Liu, Zewen

    2016-07-01

    Reconfigurable attenuators are widely used in microwave measurement instruments. Development of miniaturized attenuation devices with high precision and broadband performance is required for state-of-the-art applications. In this paper, a compact 3-bit microwave attenuator based on radio frequency micro-electro-mechanical system (RF MEMS) switches and polysilicon attenuation modules is presented. The device comprises 12 ohmic contact MEMS switches, π-type polysilicon resistive attenuation modules and microwave compensate structures. Special attention was paid to the design of the resistive network, compensate structures and system simulation. The device was fabricated using micromachining processes compatible with traditional integrated circuit fabrication processes. The reconfigurable attenuator integrated with RF MEMS switches and resistive attenuation modules was successfully fabricated with dimensions of 2.45  ×  4.34  ×  0.5 mm3, which is 1/1000th of the size of a conventional step attenuator. The measured RF performance revealed that the attenuator provides 10-70 dB attenuation at 10 dB intervals from 0.1-20 GHz with an accuracy better than  ±1.88 dB at 60 dB and an error of less than 2.22 dB at 10 dB. The return loss of each state of the 3-bit attenuator was better than 11.95 dB (VSWR  <  1.71) over the entire operating band.

  19. 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.

  20. Attenuation law of explosive stress wave in damaged rock mass

    Institute of Scientific and Technical Information of China (English)

    CHEN Shi-hai; CUI Xin-zhuang

    2001-01-01

    The attenuation regularity of explosion stress waves in damaged rocks is discussed according to physical and geometric attenuation of waves in this pa per. The relation between numerical decrement and damaged parameter is given and the results have an important significance to design and control blasting effec t accurately in a concrete rock.

  1. Attenuation law of explosive stress wave in damaged rock mass

    Institute of Scientific and Technical Information of China (English)

    陈士海; 崔新壮

    2001-01-01

    The attenuation regularity of explosion stress waves in damaged rocks is discussed according to physical and geometric attenuation of waves in this paper. The relation between numerical decrement and damaged parameter is given and the results have an important significance to design and control blasting effect accurately in a concrete rock.

  2. 16 CFR 1203.17 - Impact attenuation test.

    Science.gov (United States)

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Impact attenuation test. 1203.17 Section... SAFETY STANDARD FOR BICYCLE HELMETS The Standard § 1203.17 Impact attenuation test. (a) Impact test... the acceleration of the test headform during impact. Acceleration is measured with a...

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

    NARCIS (Netherlands)

    Horstman, E.M.; Dohmen-Janssen, C.M.; Narra, P.M.F.; Berg, van den N.J.F.; Siemerink, M.; Hulscher, S.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, s

  4. 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.

  5. Flux attenuation at NREL's High-Flux Solar Furnace

    Science.gov (United States)

    Bingham, Carl E.; Scholl, Kent L.; Lewandowski, Allan A.

    1994-10-01

    The High-Flux Solar Furnace (HFSF) at the National Renewable Energy Laboratory (NREL) has a faceted primary concentrator and a long focal-length-to-diameter ratio (due to its off-axis design). Each primary facet can be aimed individually to produce different flux distributions at the target plane. Two different types of attenuators are used depending on the flux distribution. A sliding-plate attenuator is used primarily when the facets are aimed at the same target point. The alternate attenuator resembles a venetian blind. Both attenuators are located between the concentrator and the focal point. The venetian-blind attenuator is primarily used to control the levels of sunlight failing on a target when the primary concentrators are not focused to a single point. This paper will demonstrate the problem of using the sliding-plate attenuator with a faceted concentrator when the facets are not aimed at the same target point. We will show that although the alternate attenuator necessarily blocks a certain amount of incoming sunlight, even when fully open, it provides a more even attenuation of the flux for alternate aiming strategies.

  6. X-Ray Form Factor, Attenuation and Scattering Tables

    Science.gov (United States)

    SRD 66 X-Ray Form Factor, Attenuation and Scattering Tables (Web, free access)   This database collects tables and graphs of the form factors, the photoabsorption cross section, and the total attenuation coefficient for any element (Z <= 92).

  7. The attenuation anisotropy of mudstones and shales in subsurface formations

    Institute of Scientific and Technical Information of China (English)

    SHI Ge; DENG Jixin

    2005-01-01

    We have measured the relationships in the laboratorial condition between the attenuation in three samples of mudstones and shales as well as two samples of layered sandstones and the alteration in direction, confining pressure and pore fluid. The relative contributions of different attenuation mechanisms are also discussed. Studies show that the attenuation in dry and saturated samples is strongly related to pressure and direction. The attenuation coefficient of P-wave propagating parallel to bedding (PH) is less than that of P-wave propagating vertical to bedding (PV), while the attenuation coefficient of S-wave both propagating and vibrating parallel to bedding (SH) and that of S-wave propagating vertical to bedding while vibrating parallel to bedding (SV1) are less than that of S-wave propagating parallel to bedding while vibrating vertical to bedding (SV). Under oil saturated conditions, the Biot flow attenuation acts as the dominant mechanism for waves propagating parallel to bedding, while the frame anelastic attenuation and squirt flow attenuation seem to play important roles in condition of propagation vertical to bedding.

  8. Importance of Attenuation Correction (AC) for Small Animal PET Imaging

    DEFF Research Database (Denmark)

    El Ali, Henrik H.; Bodholdt, Rasmus Poul; Jørgensen, Jesper Tranekjær;

    2012-01-01

    concentration in the same organ with and without AC revealed an overall attenuation recovery of 9–21% for MAP reconstructed images, i.e., SUV without AC could underestimate the true activity at this level. For subcutaneous tumors, the attenuation was 13 ± 4% (9–17%), for kidneys 20 ± 1% (19...

  9. A Precision Variable, Double Prism Attenuator for CO(2) Lasers.

    Science.gov (United States)

    Oseki, T; Saito, S

    1971-01-01

    A precision, double prism attenuator for CO(2) lasers, calibrated by its gap capacitance, was constructed to evaluate its possible use as a standard for attenuation measurements. It was found that the accuracy was about 0.1 dB with a dynamic range of about 40 dB.

  10. Broad beam and narrow beam attenuation in Lipowitz's metal.

    Science.gov (United States)

    el-Khatib, E E; Podgorsak, E B; Pla, C

    1987-01-01

    Attenuation properties of Lipowitz's metal have been studied for narrow and broad beams of cobalt-60 gamma rays and 4-10 MV x-rays. The measured transmitted fraction for geometries used in radiotherapy depends on the field size and depth of measurement. Therefore a calculation of dose for partially attenuated beams based on narrow beam attenuation coefficients can cause large errors in dosimetry. Our simple calculation of transmitted fractions based on primary attenuation and scattered radiation agrees quite well with the measured data for therapeutic geometries. Also given is a table for linear, mass attenuation, and mass energy absorption coefficients of Lipowitz's metal in the photon energy range from 10 keV to 10 MeV. PMID:3104738

  11. 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.

  12. Determination of mass attenuation coefficient in wood and leaves of typical trees by gamma-ray attenuation technique

    International Nuclear Information System (INIS)

    Using an 241 Am source the mass attenuation coefficient of different woods and leaves of typical species of the Atlantic Forest were measured. The results for natural wood, dry wood and dry leaves indicate that the variation is very small among different species. However, woods present a higher attenuation than leaves, both depending on their water content. (author). 10 refs., 3 figs., 1 tab

  13. 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

  14. Photochemical Attenuation of Pesticides in Prairie Potholes

    Science.gov (United States)

    Zeng, T.; Arnold, W. A.

    2013-12-01

    Prairie potholes are small, shallow, glacially-derived wetlands scattered across a vast region extending from Midwestern United States into south central Canada known as the Prairie Pothole Region (PPR). They constitute one of the largest inland wetland systems on Earth and play a prominent role in sustaining the regional biodiversity and productivity. Throughout the PPR, historic and contemporary conversion of native prairie for agriculture resulted in a pronounced loss of potholes. Remaining potholes have become interspersed within a matrix of agricultural landscape and trap nonpoint source pollutants such as pesticides from adjacent farmland, which has raised concerns regarding negative impacts on the water quality of downstream water bodies. The fate and persistence of pesticides in potholes, however, remains largely unexplored. Prairie potholes are typically characterized by shallow depth (i.e., large photic zone) and high levels of dissolved organic matter (DOM), making them ideal for photochemical reactions. In this context, we collected pothole water samples from North Dakota to investigate the rates and mechanisms of sunlight-induced attenuation of pesticides. The photodegradation kinetics and pathways of sixteen pesticides in the pothole water were monitored under both simulated and natural sunlight. For most pesticides, photolysis accelerated in the pothole water relative to the buffer control, which pointed to the importance of photosensitized processes (i.e., indirect photolysis). Upon solar irradiation, a mixture of photochemically produced reactive intermediates (PPRIs), such as carbonate radical, hydroxyl radical, singlet oxygen, and triplet-excited state DOM, formed in the pothole water. The major pathways through which pesticides degraded were inferred from the relative contribution attributable to specific PPRIs via quencher experiments. Different classes of pesticides exhibited contrasting photochemical behavior, but singlet oxygen and triplet

  15. Silibinin attenuates allergic airway inflammation in mice

    International Nuclear Information System (INIS)

    Highlights: ► Silibinin diminishes ovalbumin-induced inflammatory reactions in the mouse lung. ► Silibinin reduces the levels of various cytokines into the lung of allergic mice. ► Silibinin prevents the development of airway hyperresponsiveness in allergic mice. ► Silibinin suppresses NF-κB 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-κB) pathway. Because NF-κB 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-κB activation. These findings indicate that silibinin protects against OVA-induced airway inflammation, at least in part via downregulation of NF-κB activity. Our data support the utility of silibinin as a potential medicine for the treatment of asthma.

  16. Ultrasonic attenuation in rare-earth monoarsenides

    Indian Academy of Sciences (India)

    BHALLA VYOMA; SINGH DEVRAJ; JAIN S K; KUMAR RAJ

    2016-06-01

    The present paper deals with the theoretical calculation of mechanical and thermophysical properties of rare-earth monoarsenides, XAs (X: Np, Pu, Th and U) using elastic constants as the input parameters. These second- and third-order elastic constants (SOECs and TOECs) are determinedin the temperature range 100–500K using Coulomb and Born–Mayer potential upto second nearest neighbours. In order to provide the link between mechanical and dynamical behaviour of crystals, parameters such as Young’s modulus, bulk modulus, Poisson’s ratio etc. are also calculated.In addition, the Cauchy relationship is obeyed by the chosen monoarsenides and are fairly anisotropic, which results in the measurement of longitudinal and shear wave velocities along $\\langle100 \\rangle$, $\\langle110\\rangle$ and $\\langle 111\\rangle$ directions. 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 phonon–phonon interaction$\\alpha/f^2_{\\rm p−p}$ and thermoelastic loss $\\alpha/f ^{2}$th are computed for XAs from 100 to 500K using Mason’s theory. It further helps in evaluating the microstructural properties of the chosen materials. The obtained results indicate that XAs is mechanically stable and are compared with data availablein the literature.

  17. A prototype piecewise-linear dynamic attenuator

    Science.gov (United States)

    Hsieh, Scott S.; Peng, Mark V.; May, Christopher A.; Shunhavanich, Picha; Fleischmann, Dominik; Pelc, Norbert J.

    2016-07-01

    The piecewise-linear dynamic attenuator has been proposed as a mechanism in CT scanning for personalizing the x-ray illumination on a patient- and application-specific basis. Previous simulations have shown benefits in image quality, scatter, and dose objectives. We report on the first prototype implementation. This prototype is reduced in scale and speed and is integrated into a tabletop CT system with a smaller field of view (25 cm) and longer scan time (42 s) compared to a clinical system. Stainless steel wedges were machined and affixed to linear actuators, which were in turn held secure by a frame built using rapid prototyping technologies. The actuators were computer-controlled, with characteristic noise of about 100 microns. Simulations suggest that in a clinical setting, the impact of actuator noise could lead to artifacts of only 1 HU. Ring artifacts were minimized by careful design of the wedges. A water beam hardening correction was applied and the scan was collimated to reduce scatter. We scanned a 16 cm water cylinder phantom as well as an anthropomorphic pediatric phantom. The artifacts present in reconstructed images are comparable to artifacts normally seen with this tabletop system. Compared to a flat-field reference scan, increased detectability at reduced dose is shown and streaking is reduced. Artifacts are modest in our images and further refinement is possible. Issues of mechanical speed and stability in the challenging clinical CT environment will be addressed in a future design.

  18. 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.

  19. Atorvastatin attenuates oxidative stress in Alzheimer's disease

    Institute of Scientific and Technical Information of China (English)

    Cai Zhiyou; Yan Yong; Wang Yonglong

    2008-01-01

    Objective: To investigate serum level of SOD, MDA, ox-LDL, AchE and Ach in AD, to study atorvastatin influence on serum level of SOD, MDA, ox-LDL, AchE and Acb in AD and its neuroprotection mechanisms. Methods Subjects were divided into: normal blood lipid level group with Alzheimer's disease (A), higher blood lipid level group with Alzheimer's disease (AH), normal blood lipid level Alzheimer's disease group with atorvastatin treeatment (AT),higher blood lipid level Alzheimer's disease group with atorvastatin treeatment(AHT). Ox-LDL was measured by enzyme linked immunosorbent assay; SOD, MDA, ox-LDL, AchE, Ach and blood lipid level in AD was measured by biochemistry. Results: The serum level of MDA, AchE in AH group after atorvastatin treatment is lower ;The serum level of SOD, Ach in AH group is more increased than that of in A group; The serum level of ox-LDL in AH, A groups is lower than that of in A group; The dementia degree is lower after atorvastatin treatment. Conclusion: Atorvastatin can decrease serum level of MDA, AchE and ox-LDL, and increase that of SOD, Acb, and attenuate dementia symptom in AD, especially, with hyperlipemia. The hypothesis of atorvastatin neuroprotection is concluded that atorvastatin may restrain free radical reaction and retard oxidation in AD.

  20. 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 < 0.05). The co-injection of minocycline with iron significantly reduced iron-induced brain swelling (n = 5, p < 0.01). Albumin, a marker of BBB disruption, was measured by Western blot analysis. Minocycline significantly decreased albumin protein levels in the ipsilateral basal ganglia (p < 0.01). Iron-handling protein levels in the brain, including ceruloplasmin and transferrin, were reduced in the minocycline co-injected animals. In conclusion, the present study suggests that minocycline attenuates brain swelling and BBB disruption via an iron-chelation mechanism. PMID:26463975

  1. 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.

  2. 土壤中落叶型棉花黄萎病菌的分子检测方法%Detection of defoliating pathotype of Verticillium dahliae in soil by nested-PCR

    Institute of Scientific and Technical Information of China (English)

    张昕; 简桂良; 林玲; 邓晟; 周益军

    2011-01-01

    为了建立快速、准确检测土壤中落叶型棉花黄萎病菌的方法,本试验将提取自落叶型棉花黄萎病菌菌株V991的DNA稀释成不同浓度,同时提取在灭菌土中接入不同数量的V991孢子后制成的人工病土中的DNA,并采用五点取样法提取自然土样中的DNA,选用落叶型黄萎病菌的特异性巢式PCR引物,对上述DNA样品进行检测.结果显示:采用巢式PCR法可检测到落叶型棉花黄萎病菌菌株V991的DNA浓度为1×10-4mg/L,同时每克人工病土中含有10个V991孢子也可被检测到,该方法灵敏性比常规PCR法提高2~5个数量级.用该方法对所取自然土样讲行检测,均可检测到落叶型棉花黄萎病菌的存在.%To develop of a specific and fast method for early detection of the defoliating pathotype of Verticillium dahliae(D V. Dahliae) in soil, DNA extracted from D V. Dahliae strain V991 and artificial infested soil which contained the V991conidium was detected with nested primers specific for D V. Dahliae. The results showed that DNA concentration was 1×104 mg/L from D V. Dahliae strain V991 and 10 conidium of D V. Dahliae strain V991 existed in per gram of artificial infested soil. The sensitivity of nested-PCR for dection of D V. Dahliae in soil was much better than the traditioanal PCR.

  3. 三重PCR检测草莓灰霉病菌、炭疽病菌和黄萎病菌%Triplex PCR Detection of Botrytis cinerea, Colletotrichum gloeosporioides and Verticillium dahliae in Infected Strawberry Plant Tissues

    Institute of Scientific and Technical Information of China (English)

    王楠; 王剑; 尹丹韩; 高观朋; 王伟

    2010-01-01

    [目的]探索和优化检测条件,建立同时检测草莓灰霉病菌Botrytis cinarea,炭疽病菌Colletotrichum gloeosporioides和黄萎病菌Verticillium dahliae的三重PCR检测体系,为3种病害的早期快速诊断和鉴定提供技术和方法.[方法]选择可以组合的3种病原菌特异引物,研究多重PCR的影响因素,优化PCR退火温度,采用正交试验方法,以3个引物组、Taq DNA聚合酶、dNTP和Mg2+六因素三水平优化多重PCR体系.[结果]建立并验证适合上述草莓主要病原菌的三重PCR最佳检测体系,可分别扩增出729、539和450 bp的特异条带,最适退火温度为50℃,25μL的反应体系中含有0.32 μmol·L-1 C729+/-,0.032 μmol·L-1 DB19/DB22、0.32 μmol·L-1 CgInt/ITS4,1.5 U Taq聚合酶、0.15 mmol·L-1 dNTP、1.6 mmol·L-1 MgCI2.[结论]利用上述引物组合和反应体系进行三重PCR检测,能够快速从田间发病植株和土壤中将草莓灰霉病菌、草莓炭疽病菌和草莓黄萎病菌检测出来,灵敏度可以达到10 Pg菌丝DNA.

  4. 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.

  5. Rain Attenuation Prediction for Terrestrial Microwave Link in Bangladesh

    Directory of Open Access Journals (Sweden)

    HOSSAIN Sakir

    2014-05-01

    Full Text Available Rain attenuation is a major shortcoming of microwave transmission. As a subtropical country, Bangladesh is one of the highest rainy areas of the world. Thus, designing a terrestrial microwave link is a serious challenge to the engineers. In this paper, the annual rain rate and monthly variation of rate are predicted for different percentage of time of the year from the measured rainfall data. Using ITU rain model for terrestrial microwave communication, the rain attenuation is predicted for five major cities of Bangladesh, namely Dhaka, Chittagong, Rajshahi, Sylhet, and Khulna. It is found that rain attenuation is the most severe in Sylhet and least in Rajshahi. The attenuation is estimated for different frequency and polarization. A horizontally polarized signal encounters 15% more rain attenuation than that of vertically polarized signal. It is also found that attenuation in Rajshahi is about 20% lesser than that in Sylhet. Thus, the horizontally polarized transmission in Rajshahi experiences about 5% less attenuation than the vertically polarized transmission in Sylhet.

  6. Molecular basis of live-attenuated influenza virus.

    Directory of Open Access Journals (Sweden)

    Wen He

    Full Text Available Human influenza is a seasonal disease associated with significant morbidity and mortality. The most effective means for controlling infection and thereby reducing morbidity and mortality is vaccination with a three inactivated influenza virus strains mixture, or by intranasal administration of a group of three different live attenuated influenza vaccine strains. Comparing to the inactivated vaccine, the attenuated live viruses allow better elicitation of a long-lasting and broader immune (humoral and cellular response that represents a naturally occurring transient infection. The cold-adapted (ca influenza A/AA/6/60 (H2N2 (AA ca virus is the backbone for the live attenuated trivalent seasonal influenza vaccine licensed in the United States. Similarly, the influenza A components of live-attenuated vaccines used in Russia have been prepared as reassortants of the cold-adapted (ca H2N2 viruses, A/Leningrad/134/17/57-ca (Len/17 and A/Leningrad/134/47/57-ca (Len/47 along with virulent epidemic strains. However, the mechanism of temperature-sensitive attenuation is largely elusive. To understand how modification at genetic level of influenza virus would result in attenuation of human influenza virus A/PR/8/34 (H1N1,A/PR8, we investigated the involvement of key mutations in the PB1 and/or PB2 genes in attenuation of influenza virus in vitro and in vivo. We have demonstrated that a few of residues in PB1 and PB2 are critical for the phenotypes of live attenuated, temperature sensitive influenza viruses by minigenome assay and real-time PCR. The information of these mutation loci could be used for elucidation of mechanism of temperature-sensitive attenuation and as a new strategy for influenza vaccine development.

  7. Seismic attenuation: Laboratory measurements in fluid saturated rocks

    Science.gov (United States)

    Subramaniyan, Shankar; Madonna, Claudio; Tisato, Nicola; Saenger, Erik; Quintal, Beatriz

    2014-05-01

    Seismic wave attenuation could be used as an indicator of reservoir fluids due to its dependence on rock and fluid properties. Over the past 30 years, many laboratory methodologies to study attenuation in rocks have been employed, such as ultrasonic (MHz), resonant bar (kHz) and forced oscillation methods in the low frequency range (0.01-100Hz) (Tisato & Madonna 2012; Madonna & Tisato 2013). Forced oscillation methods have gained prominence over time as the frequency range of measurements correspond to that of field seismic data acquired for oil/gas exploration. These experiments measure attenuation as the phase shift between the applied stress (sinusoidal) and measured strain. Since the magnitudes of measured phase shifts are quite low (Q-1 ~0.01-0.1) and the amplitudes of strain applied to the rock samples are of the order ~10-6 (i.e., similar orders of magnitude to seismic waves), it is challenging. A comparison of such forced oscillation setups will be presented to provide an overview of the various possibilities of design and implementation for future setups. In general, there is a lack of laboratory data and most of the published data are for sandstones. Currently, attenuation measurements are being carried out on carbonate and sandstone samples. We employ the Seismic Wave Attenuation Module (SWAM, Madonna & Tisato 2013) to measure seismic attenuation in these samples for different saturation degrees (90% and 100% water) and under three different confining pressures (5, 10 and 15MPa). Preliminary results from these investigations will be discussed. REFERENCES Madonna, C. & Tisato, N. 2013: A new seismic wave attenuation module to experimentally measure low-frequency attenuation in extensional mode. Geophysical Prospecting, doi: 10.1111/1365-2478.12015. Tisato, N. & Madonna, C. 2012: Attenuation at low seismic frequencies in partially saturated rocks: Measurements and description of a new apparatus. Journal of Applied Geophysics, 86, 44-53.

  8. 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)

  9. FSO and radio link attenuation: meteorological models verified by experiment

    Science.gov (United States)

    Brazda, Vladimir; Fiser, Ondrej; Svoboda, Jaroslav

    2011-09-01

    Institute of Atmospheric Physics of Czech Academy measures atmospheric attenuation on 60 m experimental FSO link on 830 and 1550 nm for more than three years. Visibility sensors and two 3D sonic anemometers on both transmitting and receiving site, rain gauge and many sensors enabling the refractivity index computation are spaced along the optical link. Meteorological visibility, wind turbulent energy, sonic temperature, structure index and rain rate are correlated with measured attenuation. FSO link attenuation dependence on the above mentioned parameters is analyzed. The paper shows also basic statistical behavior of the long-term FSO signal level and also the simulation of hybrid link techniques.

  10. PID Gain Tuning for Disturbance Attenuation FRIT Method

    Science.gov (United States)

    Masuda, Shiro

    This review paper shows a PID gains tuning method from one-shot experimental data generated by test signal added at input signal in an off-line manner, so that the output signal could follow the prescribed reference model output. We call the method a “disturbance attenuation FRIT method” because the test signal added at input signal is a benchmark signal evaluating disturbance attenuation property. The experimental result for helicopter attitude control model is demonstrated to show the effectiveness of the disturbance attenuation FRIT method.

  11. Esmolol vs. nitroglycerin: attenuating hemodynamic response to laryngoscopy and intubation

    Directory of Open Access Journals (Sweden)

    Cassie Held

    2016-01-01

    Full Text Available Hemodynamic response to laryngoscopy and intubation is a common occurrence with the potential for harmful effects. Many drugs have been utilized throughout the years to attenuate this response with mixed results. This review compares the efficacy of two drugs, esmolol and nitroglycerin, in attenuating hemodynamic response to laryngoscopy and intubation. A systematic review was performed compiling all previous studies detailing the efficacy of esmolol in comparison to nitroglycerin for this purpose. Esmolol was found to consistently attenuate hemodynamic responses of blood pressure and heart rate with greater efficacy than nitroglycerin, and is thus recommended over nitroglycerin for use in this role.

  12. MNAtoolbox: A Monitored Natural Attenuation Site Screening Program

    Energy Technology Data Exchange (ETDEWEB)

    Borns, David J.; Brady, Patrick V.; Brady, Warren D.; Krupka, Kenneth M.; Spalding, Brian P.; Waters, Robert D.; Zhang, Pengchu

    1999-07-12

    Screening of sites for the potential application and reliance upon monitored natural attenuation (MNA) can be done using MNAtoolbox, a web-based tool for estimating extent of biodegradation, chemical transformation, and dilution. MNAtoolbox uses site-specific input data, where available (default parameters are taken from the literature), to roughly quantify the nature and extent of attenuation at a particular site. Use of MNAtoolbox provides 3 important elements of site evaluation: (1) Identifies likely attenuation pathways, (2) Clearly identifies sites where MNA is inappropriate, and (3) Evaluates data requirements for subsequent reliance on MNA as a sole or partial corrective action.

  13. Improving EMI Attenuation in Frequency Modulated Power Converters

    OpenAIRE

    Stepins, D.

    2009-01-01

    The effect of frequency modulation on a power switching converter electromagnetic interference (EMI) attenuation is examined in this paper. A method known as “modified sawtooth” is applied for EMI attenuation in a boost converter and it is optimized in such a way to reduce EMI more effectively. The method is also verified experimentally by the use of a low power boost converter controlled via an arbitrary waveform generator. EMI attenuation up to 15 dB is achieved after using modified sawtoot...

  14. Ultrasonic attenuation measurements determine onset, degree, and completion of recrystallization

    Science.gov (United States)

    Generazio, E. R.

    1988-01-01

    Ultrasonic attenuation was measured for cold worked Nickel 200 samples annealed at increasing temperatures. Localized dislocation density variations, crystalline order and volume percent of recrystallized phase were determined over the anneal temperature range using transmission electron microscopy, X-ray diffraction, and metallurgy. The exponent of the frequency dependence of the attenuation was found to be a key variable relating ultrasonic attenuation to the thermal kinetics of the recrystallization process. Identification of this key variable allows for the ultrasonic determination of onset, degree, and completion of recrystallization.

  15. Dispersion effects on infrared spectra in attenuated total reflection

    Science.gov (United States)

    Belali, Rabah; Vigoureux, Jean-Marie; Morvan, Joseph

    1995-12-01

    A potential problem with the attenuated total reflection that is used to measure infrared spectra is described. The problem is the possibility that the anomalous dispersion associated with an infrared absorption band may cause the experimental configuration to move from the attenuated total reflection regime to the specular reflection regime, with consequent distortion of the apparent absorption bands and consequent error in the interpretation of the bands if the problem is not recognized. Key infrared spectra, attenuated total reflection, specular reflection, polyethylene terephtalate. Copyright (c) 1995 Optical Society of America

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

    International Nuclear Information System (INIS)

    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)

  17. Pyrvinium attenuates Hedgehog signaling downstream of smoothened.

    Science.gov (United States)

    Li, Bin; Fei, Dennis Liang; Flaveny, Colin A; Dahmane, Nadia; Baubet, Valérie; Wang, Zhiqiang; Bai, Feng; Pei, Xin-Hai; Rodriguez-Blanco, Jezabel; Hang, Brian; Orton, Darren; Han, Lu; Wang, Baolin; Capobianco, Anthony J; Lee, Ethan; Robbins, David J

    2014-09-01

    The Hedgehog (HH) signaling pathway represents an important class of emerging developmental signaling pathways that play critical roles in the genesis of a large number of human cancers. The pharmaceutical industry is currently focused on developing small molecules targeting Smoothened (Smo), a key signaling effector of the HH pathway that regulates the levels and activity of the Gli family of transcription factors. Although one of these compounds, vismodegib, is now FDA-approved for patients with advanced basal cell carcinoma, acquired mutations in Smo can result in rapid relapse. Furthermore, many cancers also exhibit a Smo-independent activation of Gli proteins, an observation that may underlie the limited efficacy of Smo inhibitors in clinical trials against other types of cancer. Thus, there remains a critical need for HH inhibitors with different mechanisms of action, particularly those that act downstream of Smo. Recently, we identified the FDA-approved anti-pinworm compound pyrvinium as a novel, potent (IC50, 10 nmol/L) casein kinase-1α (CK1α) agonist. We show here that pyrvinium is a potent inhibitor of HH signaling, which acts by reducing the stability of the Gli family of transcription factors. Consistent with CK1α agonists acting on these most distal components of the HH signaling pathway, pyrvinium is able to inhibit the activity of a clinically relevant, vismodegib -resistant Smo mutant, as well as the Gli activity resulting from loss of the negative regulator suppressor of fused. We go on to demonstrate the utility of this small molecule in vivo, against the HH-dependent cancer medulloblastoma, attenuating its growth and reducing the expression of HH biomarkers. PMID:24994715

  18. Acetate supplementation attenuates lipopolysaccharide-induced neuroinflammation.

    Science.gov (United States)

    Reisenauer, Chris J; Bhatt, Dhaval P; Mitteness, Dane J; Slanczka, Evan R; Gienger, Heidi M; Watt, John A; Rosenberger, Thad A

    2011-04-01

    Glyceryl triacetate (GTA), a compound effective at increasing circulating and tissue levels of acetate was used to treat rats subjected to a continual 28 day intra-ventricular infusion of bacterial lipopolysaccharide (LPS). This model produces a neuroinflammatory injury characterized by global neuroglial activation and a decrease in choline acetyltransferase immunoreactivity in the basal forebrain. During the LPS infusion, rats were given a daily treatment of either water or GTA at a dose of 6 g/kg by oral gavage. In parallel experiments, free-CoA and acetyl-CoA levels were measured in microwave fixed brains and flash frozen heart, liver, kidney and muscle following a single oral dose of GTA. We found that a single oral dose of GTA significantly increased plasma acetate levels by 15 min and remained elevated for up to 4 h. At 30 min the acetyl-CoA levels in microwave-fixed brain and flash frozen heart and liver were increased at least 2.2-fold. The concentrations of brain acetyl-CoA was significantly increased between 30 and 45 min following treatment and remained elevated for up to 4 h. The concentration of free-CoA in brain was significantly decreased compared to controls at 240 min. Immunohistochemical and morphological analysis demonstrated that a daily treatment with GTA significantly reduced the percentage of reactive glial fibrillary acidic protein-positive astrocytes and activated CD11b-positive microglia by 40-50% in rats subjected to LPS-induced neuroinflammation. Further, in rats subjected to neuroinflammation, GTA significantly increased the number of choline acetyltransferase (ChAT)-positive cells by 40% in the basal forebrain compared to untreated controls. These data suggest that acetate supplementation increases intermediary short chain acetyl-CoA metabolism and that treatment is potentially anti-inflammatory and neuroprotective with regards to attenuating neuroglial activation and increasing ChAT immunoreactivity in this model. PMID:21272004

  19. Effect of Protein Elicitor from Alterneria tenuissima on Cotton Resistance to Verticillium dahliae and Activitie S of Relative Enzyme%极细链格孢蛋白激发子诱导棉花抗病性及相关酶的变化

    Institute of Scientific and Technical Information of China (English)

    张志刚; 邱德文; 杨秀芬; 曾洪梅; 袁京京; 官春云

    2007-01-01

    本研究室从多种病原真菌中分离出的激活蛋白激发子对多种植物具有诱导抗病性、增强抗逆能力、促进植物生长的功能。由大丽轮枝菌(Verticillium dahliae)引起的棉花黄萎病一直是困扰棉花生产的重大病害,常规化学农药难以达到理想的防治效果。本文研究极细链格孢(Alterneria tenuissima)蛋白激发子对苗期棉花黄萎病的诱导抗性作用及抗病相关酶的影响。

  20. WAVE ATTENUATION OVER MUD BED: A PSEUDO-PLASTIC MODEL

    Institute of Scientific and Technical Information of China (English)

    Zhang Qing-he; Onyx W.H. Wai; Joseph H. W. Lee

    2003-01-01

    A two-layer model, with the upper layer being the perfect fluid and the lower layer being the pseudo-plastic fluid describing water wave attenuation over mud bed, was established. A simplified method based on the principle of equivalent work was applied to solve the boundary value problems. The computational results of the model show that the two-layer perfect fluid model and the perfect-viscous fluid model are all special cases of the present model. The complex nonlinear properties of wave attenuation over mud bed, can be explained by the present model, e.g., the wave dissipation rate decreases with the wave height in certain cases, while the small wave propagates over mud bed with less energy dissipation and large wave attenuates rapidly in other cases. Other factors influencing the wave attenuation were also discussed.

  1. Magnitude corrections for attenuation in the upper mantle

    International Nuclear Information System (INIS)

    Since 1969, a consistent discrepancy in seismic magnitudes of nuclear detonations at NTS compared with magnitudes of detonations elsewhere in the world has been observed. This discrepancy can be explained in terms of a relatively high seismic attenuation for compressional waves in the upper mantle beneath the NTS and in certain other locations. A correction has been developed for this attenuation based on a relationship between the velocity of compressional waves at the top of the earth's mantle (just beneath the Mohorovicic discontinuity) and the seismic attenuation further down in the upper mantle. Our new definition of body-wave magnitude includes corrections for attenuation in the upper mantle at both ends of the teleseismic body-wave path. These corrections bring the NTS oservations into line with measurements of foreign events, and enable one to make more reliable estimates of yields of underground nuclear explosions, wherever the explosion occurs

  2. 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...

  3. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    Science.gov (United States)

    Jalali, Majid; Mohammadi, Ali

    2008-05-01

    The compounds Na 2B 4O 7, H 3BO 3, CdCl 2 and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the γ rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H 3BO 3 with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds.

  4. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    International Nuclear Information System (INIS)

    The compounds Na2B4O7, H3BO3, CdCl2 and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the γ rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H3BO3 with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds

  5. Dose reduction using a dynamic, piecewise-linear attenuator

    Energy Technology Data Exchange (ETDEWEB)

    Hsieh, Scott S., E-mail: sshsieh@stanford.edu [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Electrical Engineering, Stanford University, Stanford, California 94305 (United States); Fleischmann, Dominik [Department of Radiology, Stanford University, Stanford, California 94305 (United States); Pelc, Norbert J. [Department of Radiology, Stanford University, Stanford, California 94305 and Department of Bioengineering, Stanford University, Stanford, California 94305 (United States)

    2014-02-15

    Purpose: The authors recently proposed a dynamic, prepatient x-ray attenuator capable of producing a piecewise-linear attenuation profile customized to each patient and viewing angle. This attenuator was intended to reduce scatter-to-primary ratio (SPR), dynamic range, and dose by redistributing flux. In this work the authors tested the ability of the attenuator to reduce dose and SPR in simulations. Methods: The authors selected four clinical applications, including routine full field-of-view scans of the thorax and abdomen, and targeted reconstruction tasks for an abdominal aortic aneurysm and the pancreas. Raw data were estimated by forward projection of the image volume datasets. The dynamic attenuator was controlled to reduce dose while maintaining peak variance by solving a convex optimization problem, assuminga priori knowledge of the patient anatomy. In targeted reconstruction tasks, the noise in specific regions was given increased weighting. A system with a standard attenuator (or “bowtie filter”) was used as a reference, and used either convex optimized tube current modulation (TCM) or a standard TCM heuristic. The noise of the scan was determined analytically while the dose was estimated using Monte Carlo simulations. Scatter was also estimated using Monte Carlo simulations. The sensitivity of the dynamic attenuator to patient centering was also examined by shifting the abdomen in 2 cm intervals. Results: Compared to a reference system with optimized TCM, use of the dynamic attenuator reduced dose by about 30% in routine scans and 50% in targeted scans. Compared to the TCM heuristics which are typically used withouta priori knowledge, the dose reduction is about 50% for routine scans. The dynamic attenuator gives the ability to redistribute noise and variance and produces more uniform noise profiles than systems with a conventional bowtie filter. The SPR was also modestly reduced by 10% in the thorax and 24% in the abdomen. Imaging with the dynamic

  6. 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.

  7. Attenuation of 3CM Microwaves Due to Artificial Rain

    Directory of Open Access Journals (Sweden)

    J. K. Singh

    1966-04-01

    Full Text Available Observations to study the variation of attenuation of 3cm waves due to falling of water or artificial rain are confined to the high rates of precipitation and short distance between the transmitter and receiver, due to low power of the microwave generator. A comparison of these observations and those recorded by others shows that the attenuation increases nonlinearly with the intensity of artificial rainfall which is generally assumed to be linear for the observations at lower rates of precipitation.

  8. An analysis of seismic attenuation in random porous media

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The attenuation of seismic wave in rocks has been one of the interesting research topics, but till now no poroelasticity models can thoroughly explain the strong attenuation of wave in rocks. In this paper, a random porous medium model is designed to study the law of wave propagation in complex rocks based on the theory of Biot poroelasticity and the general theory of stochastic process. This model sets the density of grain, porosity, permeability and modulus of frame as random parameters in space, and only one fluid infiltrates in rocks for the sake of better simulation effect in line with real rocks in earth strata. Numerical simulations are implemented. Two different inverse quality factors of fast P-wave are obtained by different methods to assess attenuation through records of virtual detectors in wave field (One is amplitude decay method in time domain and the other is spectral ratio method in frequency domain). Comparing the attenuation results of random porous medium with those of homogeneous porous medium, we conclude that the attenuation of seismic wave of homogeneous porous medium is far weaker than that of random porous medium. In random porous media, the higher heterogeneous level is, the stronger the attenuation becomes, and when heterogeneity σ = 0.15 in simulation, the attenuation result is consistent with that by actual observation. Since the central frequency (50 Hz) of source in numerical simulation is in earthquake band, the numerical results prove that heterogeneous porous structure is one of the important factors causing strong attenuation in real stratum at intermediate and low frequency.

  9. Rationalizing the development of live attenuated virus vaccines

    OpenAIRE

    Lauring, Adam S.; Jones, Jeremy O.; Andino, Raul

    2010-01-01

    Since the first demonstration of the protective effects of vaccinia inoculation, vaccination has been one of the medicine’s greatest successes. The design of vaccines against viral disease has evolved considerably over the last 50 years. Classically attenuated viruses, those created by passaging a virus in cultured cells, have proven to be an effective means for preventing many viral diseases, including smallpox, polio, measles, mumps, and yellow fever. However, empiric attenuation is not a r...

  10. Kramers-Kronig relationship between ultrasonic attenuation and phase velocity

    Science.gov (United States)

    Odonnell, M.; Jaynes, E. T.; Miller, J. G.

    1981-01-01

    Kramers-Kronig relations linking the attenuation and dispersion are presented for a linear acoustic system. These expressions are used as a starting point to derive approximate, nearly local expressions relating the ultrasonic attenuation at a specific frequency to the local frequency derivative of the phase velocity (i.e., dispersion). The validity of these approximate relationships is demonstrated in several acoustic systems exhibiting substantially different physical properties.

  11. Proteomic analysis of pathogenic and attenuated alcelaphine herpesvirus 1

    OpenAIRE

    Dry, Inga; Haig, David M; Inglis, Neil F.; Imrie, Lisa; Stewart, James P; Russell, George C.

    2008-01-01

    The gammaherpesvirus alcelaphine herpesvirus 1 (AlHV-1) causes malignant catarrhal fever in susceptible ungulates but infects its natural host, wildebeest, without obvious clinical signs. In tissue culture, AlHV-1 is initially predominantly cell associated and virulent but on extended culture becomes cell-free and attenuated. We wanted to determine what changes in protein composition had taken place during the transition from virulent to attenuated virus in culture. Purified virus preparation...

  12. Esmolol vs. nitroglycerin: attenuating hemodynamic response to laryngoscopy and intubation

    OpenAIRE

    Cassie Held

    2016-01-01

    Hemodynamic response to laryngoscopy and intubation is a common occurrence with the potential for harmful effects. Many drugs have been utilized throughout the years to attenuate this response with mixed results. This review compares the efficacy of two drugs, esmolol and nitroglycerin, in attenuating hemodynamic response to laryngoscopy and intubation. A systematic review was performed compiling all previous studies detailing the efficacy of esmolol in comparison to nitroglycerin for this pu...

  13. 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.

  14. Nuclear equipment to determine soil and water mass attenuation coefficients

    International Nuclear Information System (INIS)

    The feasibility of substituting the monochannel gamma spectrometer, traditionally used in the gamma ray attenuation technique, for a less sophisticated and less expensive system of integral counting is studied. The proposed system can be operated by a non-specialized person. Three detection systems were used in the determination of the mass attenuation coefficients for different types of soil and for water. (M.A.C.)

  15. Ultrasound attenuation dependence on air compression or expansion processes

    OpenAIRE

    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 are possible: 1) if the change of air volume is very slow or intensive heat exchange occurs between the system and surrounding environments, so the system stays in a thermodynamic equilibrium; theref...

  16. Radar Signal Attenuation due to Finite Radome Thickness

    OpenAIRE

    Képeši, Viktor; Labun, Ján

    2015-01-01

    Radar antennas deployed in real use usually include a protective dome, which shields them from potentially harmful weather conditions. The protective dome is typically constructed from a plastic material, which can affect the radar signal. The presented paper deals with signal attenuation caused by radar’s dome. It provides results of a computer simulation concerning this attenuation based on different thickness of the material used for radome construction. The presented results give insight ...

  17. Medical image of the week: expiratory imaging accentuates mosaic attenuation

    OpenAIRE

    Arteaga VA; Knox KS

    2013-01-01

    A 66 year old female presented with cough, fever and marked shortness of breath. Infectious work up was found to be negative. An inspiratory high resolution thoracic CT (HRCT) image (A) shows faint groundglass and mosaic lung attenuation with subtle centrilobular ill-defined nodules. However, an image obtained on expiration (B) shows more obvious mosaic attenuation which suggesting air-trapping. Due to progressive dyspnea, a lung biopsy was performed and revealed a bronchiolocentric cellu...

  18. DNA-launched live-attenuated vaccines for biodefense applications.

    Science.gov (United States)

    Pushko, Peter; Lukashevich, Igor S; Weaver, Scott C; Tretyakova, Irina

    2016-09-01

    A novel vaccine platform uses DNA immunization to launch live-attenuated virus vaccines in vivo. This technology has been applied for vaccine development against positive-strand RNA viruses with global public health impact including alphaviruses and flaviviruses. The DNA-launched vaccine represents the recombinant plasmid that encodes the full-length genomic RNA of live-attenuated virus downstream from a eukaryotic promoter. When administered in vivo, the genomic RNA of live-attenuated virus is transcribed. The RNA initiates limited replication of a genetically defined, live-attenuated vaccine virus in the tissues of the vaccine recipient, thereby inducing a protective immune response. This platform combines the strengths of reverse genetics, DNA immunization and the advantages of live-attenuated vaccines, resulting in a reduced chance of genetic reversions, increased safety, and improved immunization. With this vaccine technology, the field of DNA vaccines is expanded from those that express subunit antigens to include a novel type of DNA vaccines that launch live-attenuated viruses. PMID:27055100

  19. 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.

  20. 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

  1. Patient position alters attenuation effects in multipinhole cardiac SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Timmins, Rachel; Ruddy, Terrence D.; Wells, R. Glenn, E-mail: gwells@ottawaheart.ca [Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario K1Y 4W7 (Canada)

    2015-03-15

    Purpose: Dedicated cardiac cameras offer improved sensitivity over conventional SPECT cameras. Sensitivity gains are obtained by large numbers of detectors and novel collimator arrangements such as an array of multiple pinholes that focus on the heart. Pinholes lead to variable amounts of attenuation as a source is moved within the camera field of view. This study evaluated the effects of this variable attenuation on myocardial SPECT images. Methods: Computer simulations were performed for a set of nine point sources distributed in the left ventricular wall (LV). Sources were placed at the location of the heart in both an anthropomorphic and a water-cylinder computer phantom. Sources were translated in x, y, and z by up to 5 cm from the center. Projections were simulated with and without attenuation and the changes in attenuation were compared. A LV with an inferior wall defect was also simulated in both phantoms over the same range of positions. Real camera data were acquired on a Discovery NM530c camera (GE Healthcare, Haifa, Israel) for five min in list-mode using an anthropomorphic phantom (DataSpectrum, Durham, NC) with 100 MBq of Tc-99m in the LV. Images were taken over the same range of positions as the simulations and were compared based on the summed perfusion score (SPS), defect width, and apparent defect uptake for each position. Results: Point sources in the water phantom showed absolute changes in attenuation of ≤8% over the range of positions and relative changes of ≤5% compared to the apex. In the anthropomorphic computer simulations, absolute change increased to 20%. The changes in relative attenuation caused a change in SPS of <1.5 for the water phantom but up to 4.2 in the anthropomorphic phantom. Changes were larger for axial than for transverse translations. These results were supported by SPS changes of up to six seen in the physical anthropomorphic phantom for axial translations. Defect width was also seen to significantly increase. The

  2. Characteristics of coda wave attenuation in Yunnan area

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The characteristic of seismic coda wave attenuation in Yunnan area in 7 frequency-bands range from 1 Hz to 20 Hz was estimated by using the local earthquake's waveform data recorded from 22 Yunnan digital seismic stations.Coda attenuation Q-c1 of each station was firstly calculated by single scattering method. Then, mean free path Le and seismic albedo Bo of each station were calculated, and scattering attenuation Q-1s and intrinsic attenuation Q-1i were separated from total attenuation Q-1t by multiple lapse time window analysis based on the multiple scattering model in uniform random isotropic scattering medium. The attenuating characteristics in Yunnan show that most value of Le are in 10~30 km, with maximal within 2~6 Hz;Bo are about 0.5 at 1~2 Hz, but less than 0.5at other frequency-bands, which means Q-1i is comparable with Q-1s at 1~2 Hz, and after 1~2 Hz, Q-1i is greater than Q-1s and dominates the attenuation process. Q-1c is close to Q-1i at other frequency bands except 1~2 Hz.Results show that Q-1 especially Qs-1 varies spatially, Q-1 in eastern Yunnan zone is a bit higher than in northwestern Yunnan zone;northwestern Yunnan zone higher than southwestern Yunnan zone. Comparing with other results in global, Qs-1 in Yunnan is lower than the global average value among these results, Q-1i is higher than the global average value, and Q-1t lies the middle among these results.

  3. 环腺苷酸对向日葵大丽轮枝菌生物学特性及致病力的影响%Effect of cAMP on biological characteristics and pathogenicity of sunflower Verticillium dahliae

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    To unravel the effects of cAMP on biological characteristics and pathogenicity of sunflower pathogen Verticillium dahlia,growth rate,conidia production,germination rate of conidia spores,microsclerotia production, crude toxin and pathogenicity of V. dahliae were measured after V. dahlia cultured in medium with 10 mmol/L cAMP. Results showed that pathogen conidia was increased by 55. 45% in the medium,but conidia germination rate,microsclerotia yield,crude toxin production and disease index were reduced by 69%,46. 8%,35. 27% and 7. 28% respectively. In conclusion,exogenously cAMP promoted V. dahliae conidia yield,inhibited conidia germi-nation rate,and reduced microsclerotia yield,crude toxin production and pathogenicity. Among them,cAMP inhi-bition effect on microsclerotia formation was greater.%为探究环腺苷酸( cAMP,cyclic AMP)对向日葵大丽轮枝菌生物学特性及致病力的影响,在实验室条件下研究了外源添加cAMP(10mmol/L)后,向日葵大丽轮枝菌的菌落形态、生长速率、产孢量、分生孢子萌发率、微菌核数量、粗毒素分泌量以及致病力的变化。结果表明,外源cAMP使向日葵大丽轮枝菌分生孢子的产孢量提高了55.45%;而在含有cAMP的水琼胶培养基上培养24h后,大丽轮枝菌的分生孢子萌发率降低了69%;在含有cAMP的PDA上培养25d后,大丽轮枝菌微菌核形成的数量相比对照降低了46.8%;在含有cAMP的液体培养基中振荡培养15d后,大丽轮枝菌粗毒素的含量仅为0.156mg/mL,比对照培养液中毒素降低了35.27%。向日葵接种10mmol/L cAMP处理的大丽轮枝菌后,其病情指数为34.38,相比对照组降低了7.28%。因此,外源添加10mmol/L cAMP除了能够提高向日葵大丽轮枝菌的产孢量外,对其生长速率、分生孢子萌发率、微菌核形成的数量、粗毒素分泌量以及致病力均有不同程度的抑制作用,尤其是对微菌核

  4. 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

  5. Optimized ultrasonic attenuation measures for non-homogeneous materials.

    Science.gov (United States)

    Genovés, V; Gosálbez, J; Carrión, A; Miralles, R; Payá, J

    2016-02-01

    In this paper the study of frequency-dependent ultrasonic attenuation in strongly heterogeneous materials is addressed. To determine the attenuation accurately over a wide frequency range, it is necessary to have suitable excitation techniques. Three kinds of transmitted signals have been analysed, grouped according to their bandwidth: narrowband and broadband signals. The mathematical formulation has revealed the relation between the distribution of energy in their spectra and their immunity to noise. Sinusoidal and burst signals have higher signal-to-noise ratios (SNRs) but need many measurements to cover their frequency range. However, linear swept-frequency signals (chirp) improve the effective bandwidth covering a wide frequency range with a single measurement and equivalent accuracy, at the expense of a lower SNR. In the case of highly attenuating materials, it is proposed to use different configurations of chirp signals, enabling injecting more energy, and therefore, improving the sensitivity of the technique without a high time cost. Thus, if the attenuation of the material and the sensitivity of the measuring equipment allows the use of broadband signals, the combination of this kind of signal and suitable signal processing results in an optimal estimate of frequency-dependent attenuation with a minimum measurement time. PMID:26432190

  6. Seismic motion attenuation relations in Sichuan and adjacent areas

    Institute of Scientific and Technical Information of China (English)

    LEI Jian-cheng; GAO Meng-tan; YU Yan-xiang

    2007-01-01

    The Sichuan and adjacent areas is divided into southwest China region (SWCR) and Sichuan Basin region (SCBR) according to tectonic backgrounds and seismic damage distribution features. 96 modern destructive earthquakes in SWCR and 40 in SCBR are gathered respectively. All their magnitude parameters are checked. Based on the statistic relations between epicentral intensity and magnitude as well as relation between sensible radius and magnitude, the near and far field seismic intensity attenuation features are represented and controlled. And then the seismic intensity attenuation relations along major axis, minor axis and mean axis are established separately. The systematic deviations of surface wave magnitude between China seismograph network and U.S. seismograph network are considered in this paper. By making use of the new attenuation relations of bedrock horizontal ground acceleration response spectrum in west U.S., the attenuation relations of bedrock horizontal ground acceleration response spectrum in SWCR and SCBR are digital transformed based on the attenuation model considering acceleration saturation of distance and magnitude in near field.

  7. Simultaneous inversion for velocity and attenuation by waveform tomography

    Science.gov (United States)

    Gao, Fengxia; Wang, Yanghua

    2016-08-01

    Seismic waveform tomography can invert for the velocity and attenuation (Q- 1) variations simultaneously. For this simultaneous inversion, we propose two strategies for waveform tomography. First, we analyze the contributions of the real part and the imaginary part of the gradients, associated with the velocity and attenuation parameters respectively, and determine that the combination of the real part of the gradient subvector for the velocity parameter and the imaginary part of the gradient subvector for the attenuation parameter would produce an optimal inversion result. Second, we attempt to balance the sensitivities of the objective function to the velocity and the attenuation parameters. Considering the magnitude differences between these two-type parameters in the simultaneous inversion, we apply preliminarily a normalization to both the velocity model and the attenuation model. However, for balancing their sensitivities, we further adjust the corresponding model updates using a tuning factor. We determine this tuning parameter adaptively, based on the sensitivities of these two parameters, at each iteration. Numerical tests demonstrate the feasibility and reliability of these two strategies in full waveform inversion.

  8. Pentoxifylline Attenuates Cardiac Remodeling Induced by Tobacco Smoke Exposure

    Directory of Open Access Journals (Sweden)

    Marcos Minicucci

    2016-01-01

    Full Text Available Abstract Background: 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. Objective: The present study tested the hypothesis that pentoxifylline would attenuate cardiac remodeling induced by smoking. Methods: 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%. Results: 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. Conclusion: 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.

  9. Model-based design of growth-attenuated viruses.

    Directory of Open Access Journals (Sweden)

    Kwang-Il Lim

    2006-09-01

    Full Text Available Live-virus vaccines activate both humoral and cell-mediated immunity, require only a single boosting, and generally provide longer immune protection than killed or subunit vaccines. However, growth of live-virus vaccines must be attenuated to minimize their potential pathogenic effects, and mechanisms of attenuation by conventional serial-transfer viral adaptation are not well-understood. New methods of attenuation based on rational engineering of viral genomes may offer a potentially greater control if one can link defined genetic modifications to changes in virus growth. To begin to establish such links between genotype and growth phenotype, we developed a computer model for the intracellular growth of vesicular stomatitis virus (VSV, a well-studied, nonsegmented, negative-stranded RNA virus. Our model incorporated established regulatory mechanisms of VSV while integrating key wild-type infection steps: hijacking of host resources, transcription, translation, and replication, followed by assembly and release of progeny VSV particles. Generalization of the wild-type model to allow for genome rearrangements matched the experimentally observed attenuation ranking for recombinant VSV strains that altered the genome position of their nucleocapsid gene. Finally, our simulations captured previously reported experimental results showing how altering the positions of other VSV genes has the potential to attenuate the VSV growth while overexpressing the immunogenic VSV surface glycoprotein. Such models will facilitate the engineering of new live-virus vaccines by linking genomic manipulations to controlled changes in virus gene-expression and growth.

  10. 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.

  11. Photon attenuation coefficients and shielding effects of Jordanian building materials

    International Nuclear Information System (INIS)

    Highlights: • The mass attenuation coefficients were calculated for the 50–3000 keV gamma-ray energy. • Values obtained were used to evaluate the protection provided by different building. • Significant benefits could be achieved in using the basement and lower floors. - Abstract: The present study was conducted to investigate the attenuation properties of building materials commonly used in Jordan. The photon interactions with materials of interest were discussed in terms of mass attenuation coefficients for the 50–3000 keV gamma-ray energy range. The linear attenuation coefficients were measured at several photon energies using a NaI(Tl) detector and a narrow beam geometry technique. The values obtained were used to evaluate the shielding provided by different construction styles, against a hypothetical release of radioactive material as a function of the photon energy of the released material. The results obtained revealed that wall mass thickness and material chemical compositions, of the investigated construction styles, are crucial factors in shielding against radiation. An exterior wall with mass thickness of 52 g/cm2, attenuates more than 98% of the incident photons of energy 662 keV. Moreover, the addition of a high density limestone layer to the face of a concrete wall, has increased its shielding effectiveness by about 10%

  12. Attenuation of Landfill Leachate In Unsaturated Sandstone

    Science.gov (United States)

    Butler, A. P.; Brook, C.; Godley, A.; Lewin, K.; Young, C. P.

    Landfill leachate emanating from old "dilute and disperse" sites represents a potential (and in many cases actual) threat to the integrity of groundwater. Indeed, this concern has been included in EU legislation (80/86/EEC), where key contaminants (e.g. ammonia, various toxic organic compounds and heavy metals) are explicitly highlighted in terms of their impact on groundwater. In the UK, whilst there are a substantial number of unlined landfills sited on major aquifers, many of these are in locations where there is a substantial unsaturated zone. Thus, there exists the opportunity for the modification and attenuation of contaminants prior to it encountering the water table. An understanding of likely changes in leachate content and concentrations at such sites will enable a more comprehensive assessment of the potential risks and liabilities posed by such sites to be evaluated. The Burntstump landfill, situated 8 km north of Nottingham (UK), is sited on an outcrop of Sherwood sandstone. The fine friable sand has been quarried since the 1960s and the excavated volume used to store municipal waste. Filling at the site commenced in the mid 1970s and originally was unlined. In 1978 the first of what was to become a series of boreholes was installed within an area of roughly 5 m radius over one of the original waste cells. Cores of the waste and underlying sandstone were extracted and analysed for a range of physical and chemical parameters. The most recent set of analyses were obtained in 2000. The series of investigations therefore provide an important record of leachate migration and modification through the unsaturated zone for over twenty years. The progression of the leachate front is clearly delineated by the chloride concentration profile with an average velocity of around 1.6 m.yr-1. Combining this value with an average (and reasonably uniform) measured moisture content of about 7% gives a mean inter-granular specific discharge of 110 mm.yr-1. An interesting

  13. Attenuation of ultrasonic waves in coal-water slurries

    Energy Technology Data Exchange (ETDEWEB)

    Sheen, S.H.; Raptis, A.C.

    1979-02-01

    Attenuation of ultrasonic waves in coal-water slurries was investigated in the frequency range of 200 kHz to 1 MNZ (up to 30% by weight). The coal used in this study was West Kentucky number nine coal with particle size ranging from 90 to 30 ..mu..m. Attenuation data show a linear dependence on both frequency and coal concentration in the region of investigation. Results were compared with theoretical predictions from the equations derived by Urick, and by Allegra and Hawley. The experimental attenuation was found to be higher than that from the theories by an order of magnitude. The discrepancy is discussed and further investigations are suggested. Results of this work provide valuable information for the design of an ultrasonic mass flowmeter for coal-conversion processes.

  14. Long term attenuation measurements on optical ground wires

    Energy Technology Data Exchange (ETDEWEB)

    Lamarche, L.; Gagnon, D.; Miron, M. [Hydro-Quebec, Varennes, Quebec1 (Canada)

    1996-11-01

    The attenuation stability of optical fibers integrated in optical ground wires (OPGW) cables over temperature and time is of paramount importance in the planning of long distance links. The authors report here a mean thermal attenuation dependence of 5.5{center_dot}10{sup {minus}5} dB/(km{center_dot}C) at 1,550 nm, on a 220 km span of dispersion shifted (DS) fibers of an installed OPGW cable. This optical link is installed in the James Bay region over a 735 kV power line where temperature varies from {minus}40 C to +30 C annually. The data sample presented covers 1.5 year starting December 1993. The data sample presented covers 1.5 year starting December 1993. During that period, the authors also observed a temporal evolution of the attenuation described by the empirical relation A = A{sub 0} (t{minus}t{sub 0}){sup 0.00394}.

  15. 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.

  16. Fiber movements and sound attenuation in glass wool

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1999-01-01

    . The attenation was computed from the fiber diameters and their density, which was found from the mass density. Measured attenuation is lower than the values calculated. Nevertheless, if the density is adjusted, a complete fit is obtained between experimental and theoretical values for frequencies 50-5000 Hz........ 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...

  17. Broadband fractal acoustic metamaterials for low-frequency sound attenuation

    Science.gov (United States)

    Song, Gang Yong; Cheng, Qiang; Huang, Bei; Dong, Hui Yuan; Cui, Tie Jun

    2016-09-01

    We fabricate and experimentally characterize a broadband fractal acoustic metamaterial that can serve to attenuate the low-frequency sounds at selective frequencies ranging from 225 to 1175 Hz. The proposed metamaterials are constructed by the periodic Hilbert fractal elements made of photosensitive resin via 3D printing. In analogy to electromagnetic fractal structures, it is shown that multiple resonances can also be excited in the acoustic counterpart due to their self-similar properties, which help to attenuate the acoustic energy in a wide spectrum. The confinement of sound waves in such subwavelength element is evidenced by both numerical and experimental results. The proposed metamaterial may provide possible alternative for various applications such as the noise attenuation and the anechoic materials.

  18. 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.

  19. Gamma ray attenuation in a developed borate glassy system

    International Nuclear Information System (INIS)

    Measurements and calculations of gamma ray attenuation coefficients in glass barriers of xBaO–5ZnO–5MgO–14Na2O–-1Li2O–(75−x)B2O3, previously prepared by the melt-quenching technique [1], were performed for γ-ray of energies 121.8, 244.7, 344.14, 661.66, 778.7, 974, 1086.7, 1173.24, 1332.5, and 1407.9 keV; which emitted from 152Eu, 137Cs, and 60Co radioactive gamma ray sources. The transmitted γ-rays were detected by 3″×3″ and 5″×5″ NaI (Tl) scintillation γ-ray spectrometers, and a highly calibrated survey meter. The mass attenuation coefficients of γ-rays (σ(E)) were deduced from the attenuation curves, while the WinXCom computer program (version 3.1) was used to calculate the mass attenuation coefficients of γ-rays for such energies at different barium concentrations of a glassy system. A good agreement between both experimental and theoretical results was achieved as well as results obtained by other workers in similar field. - Highlights: • Design new glass system can be used as nuclear radiation shielding material. • Three different systems were used to measure γ-ray attenuation coefficients. • The γ-ray attenuation coefficients in this glass system were measured for 10 γ-energy lines. • Good agreement between experimental, theoretical, and results by other workers have been achieved. • Improvement of σ and HVL by increasing BaO concentration up to 50% in our glassy system

  20. Fast self-attenuation determination of low energy gamma lines.

    Science.gov (United States)

    Haddad, Kh

    2016-09-01

    Linear correlation between self-attenuation factor of 46.5keV ((210)Pb) and the 1764keV, 46.5 counts ratio has been developed in this work using triple superphosphate fertilizer samples. Similar correlation has been also developed for 63.3keV ((238)U). This correlation offers simple, fast, and accurate technique for self-attenuation determination of low energy gamma lines. Utilization of 46.5keV in the ratio has remarkably improved the technique sensitivity in comparison with other work, which used similar concept. The obtained results were used to assess the validity of transmission technique. PMID:27337648

  1. Heat radiative characteristics of ultra-attenuated materials

    Institute of Scientific and Technical Information of China (English)

    Dehong Xia; Yonghong Wu

    2004-01-01

    From the microstructure of heat radiation, the interaction between the incident heat radiative wave and the electromagnetism syntonic wave is analyzed to reveal the emission, absorption, transmission and reflection mechanisms of the incident heat radiative wave in materials. Based on Lorentz dispersion theory, the effect of optical parameters on heat radiative characteristics is also analyzed. The method of ultra-attenuation and nanocrystallization improving the heat radiative characteristics of the material and the emissivity dispersion of the ultra-attenuated materials are brought to light.

  2. Quasi-optical attenuators for ALMA band 10 receiver

    Science.gov (United States)

    Gonzalez, A.; Fujii, Y.; Kaneko, K.; Uzawa, Y.

    2011-12-01

    Simple quasi-optical attenuators based on beam truncation have been designed, fabricated and tried on ALMA band 10 receivers (787-950 GHz) with optimal results. The design is based on physical-optics simulations considering effects of diffraction. The use of these attenuators allows flexibility in the design of the local oscillator (LO) quasi-optical injection scheme depending on the specific performance of components for each of the 73 ALMA band 10 receivers. In particular, they have proven very effective to keep system noise within the stringent ALMA requirements (230 K at 80% of 787-950 GHz band).

  3. Medical image of the week: expiratory imaging accentuates mosaic attenuation

    Directory of Open Access Journals (Sweden)

    Arteaga VA

    2013-05-01

    Full Text Available A 66 year old female presented with cough, fever and marked shortness of breath. Infectious work up was found to be negative. An inspiratory high resolution thoracic CT (HRCT image (A shows faint groundglass and mosaic lung attenuation with subtle centrilobular ill-defined nodules. However, an image obtained on expiration (B shows more obvious mosaic attenuation which suggesting air-trapping. Due to progressive dyspnea, a lung biopsy was performed and revealed a bronchiolocentric cellular interstitial pneumonia with non-caseating granuloma consistent with subacute hypersensitivity pneumonitis.

  4. Evaluation of X ray attenuation by means of radiographic images

    International Nuclear Information System (INIS)

    This paper's main goal is to adopt a qualitative methodology to evaluate the attenuation of x-radiation through X-ray images in polymeric materials plus residual lead. To determinate the images it was initially used an experimental setup at the Laboratory for Materials Diagnostics LACTEC. These results correspond to a more qualitative analysis, even with quantitative answers. Through analysis of radiographic images we can measure the intensity of radiation that goes through the plate, making possible to establish a relationship between the attenuation coefficient and the thickness of the material. (author)

  5. 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

    .3%) and lowest for spongCT (–2.2%, range: 0.0% to –13.7%). Conclusions: In PET/MR imaging using standard MR-AC PET uptake values in soft lesions and bone lesions are underestimated by about 10%. In individual patients this bias can be as high as 22%, which is significant during clinical follow-up exams. If bone...... segmentation is available, then assigning a fixed attenuation value of spongious bone to all bone structures appears reasonable and results in only a minor bias of 5%, or less in uptake values of soft tissue and bone lesions.......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...

  6. Research on attenuation characteristic of sound wave in coal or rock body

    Institute of Scientific and Technical Information of China (English)

    NIE Bai-sheng; HE Xue-qiu; LI Xiang-chun; GAO Hong

    2007-01-01

    In order to using power sound wave increase permeability of coal, rules of attenuation of sound wave in coal should be studied. In this paper, characteristic and mechanism of attenuation of sound wave in coal was researched according to acoustic theory and attenuation coefficients was estimated by acoustic parameter of coal. The research results show that the main attenuation mechanism of sound wave in coal is absorption attenuation and scattering attenuation. The absorption attenuation includes viscous absorption, thermal conduction absorption and relaxation absorption. Attenuation coefficient of sound wave in gaseous coal is 38.5 Np/m. Researches on attenuation characteristic of sound wave will provide the theoretical basis for power sound wave improving permeability of coal and accelerating desorption of coal bed gas.

  7. Emission-based estimation of lung attenuation coefficients for attenuation correction in time-of-flight PET/MR

    International Nuclear Information System (INIS)

    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

  8. Importance of Attenuating Quadriceps Activation Deficits after Total Knee Arthroplasty

    OpenAIRE

    Thomas, Abbey C.; Jennifer E Stevens-Lapsley

    2012-01-01

    Total knee arthroplasty (TKA) is associated with persistent quadriceps dysfunction. Since quadriceps dysfunction impairs functional performance, minimizing quadriceps dysfunction by attenuating central activation deficits early after surgery may improve function later in life. Rehabilitation strategies incorporating neuromuscular electrical stimulation and early, aggressive quadriceps strengthening may prove beneficial. Further, surgical approaches such as minimally invasive TKA may minimize ...

  9. Gamma ray attenuation coefficient measurement for neutron-absorbent materials

    Energy Technology Data Exchange (ETDEWEB)

    Jalali, Majid [Isfahan Nuclear Science and Technology Research Institute (NSTRT), Reactor and Accelerators Research and Development School, Atomic Energy Organization (Iran, Islamic Republic of)], E-mail: m_jalali@entc.org.ir; Mohammadi, Ali [Faculty of Science, Department of Physics, University of Kashan, Km. 6, Ravand Road, Kashan (Iran, Islamic Republic of)

    2008-05-15

    The compounds Na{sub 2}B{sub 4}O{sub 7}, H{sub 3}BO{sub 3}, CdCl{sub 2} and NaCl and their solutions attenuate gamma rays in addition to neutron absorption. These compounds are widely used in the shielding of neutron sources, reactor control and neutron converters. Mass attenuation coefficients of gamma related to the four compounds aforementioned, in energies 662, 778.9, 867.38, 964.1, 1085.9, 1173, 1212.9, 1299.1,1332 and 1408 keV, have been determined by the {gamma} rays transmission method in a good geometry setup; also, these coefficients were calculated by MCNP code. A comparison between experiments, simulations and Xcom code has shown that the study has potential application for determining the attenuation coefficient of various compound materials. Experiment and computation show that H{sub 3}BO{sub 3} with the lowest average Z has the highest gamma ray attenuation coefficient among the aforementioned compounds.

  10. Engineering attenuated virulence of a Theileria annulata-infected macrophage.

    Directory of Open Access Journals (Sweden)

    Nadia Echebli

    Full Text Available Live attenuated vaccines are used to combat tropical theileriosis in North Africa, the Middle East, India, and China. The attenuation process is empirical and occurs only after many months, sometimes years, of in vitro culture of virulent clinical isolates. During this extensive culturing, attenuated lines lose their vaccine potential. To circumvent this we engineered the rapid ablation of the host cell transcription factor c-Jun, and within only 3 weeks the line engineered for loss of c-Jun activation displayed in vitro correlates of attenuation such as loss of adhesion, reduced MMP9 gelatinase activity, and diminished capacity to traverse Matrigel. Specific ablation of a single infected host cell virulence trait (c-Jun induced a complete failure of Theileria annulata-transformed macrophages to disseminate, whereas virulent macrophages disseminated to the kidneys, spleen, and lungs of Rag2/γC mice. Thus, in this heterologous mouse model loss of c-Jun expression led to ablation of dissemination of T. annulata-infected and transformed macrophages. The generation of Theileria-infected macrophages genetically engineered for ablation of a specific host cell virulence trait now makes possible experimental vaccination of calves to address how loss of macrophage dissemination impacts the disease pathology of tropical theileriosis.

  11. The Ultraviolet Attenuation Law in Backlit Spiral Galaxies

    CERN Document Server

    Keel, William C; Holwerda, Benne W; Lintott, Chris J; Schawinski, Kevin

    2014-01-01

    (Abridged) The effective extinction law (attenuation behavior) in galaxies in the emitted ultraviolet is well known only for actively star-forming objects and combines effects of the grain properties, fine structure in the dust distribution, and relative distributions of stars and dust. We use GALEX, XMM Optical Monitor, and HST data to explore the UV attenuation in the outer parts of spiral disks which are backlit by other UV-bright galaxies, starting with candidates provided by Galaxy Zoo participants. Our analysis incorporates galaxy symmetry, using non-overlapping regions of each galaxy to derive error estimates on the attenuation measurements. The entire sample has an attenuation law close to the Calzetti et al. (1994) form; the UV slope for the overall sample is substantially shallower than found by Wild et al. (2011), a reasonable match to the more distant galaxies in our sample but not to the weighted combination including NGC 2207. The nearby, bright spiral NGC 2207 alone gives accuracy almost equal ...

  12. Nuclear Attenuation of Charged Mesons in Deep Inelastic Scattering

    CERN Document Server

    Akopov, N Z; Grigoryan, L A

    2002-01-01

    We propose extended version of stationary string model to describe the nuclear attenuation. This model takes into account flavour content of particles and allows to include into consideration all hadrons created from string. The predictions of the model are compared with experimental results obtained by HERMES collaboration (DESY) on different nuclei (N and Kr).

  13. Attenuation of Rayleigh Surface Waves in a Porous Material

    Institute of Scientific and Technical Information of China (English)

    DEBBOUB Salima; BOUMA(I)ZA Youcef; BOUDOUR Amar; TAHRAOUI Tarek

    2012-01-01

    Using acoustic microscopy at higher frequency,we show the velocity evolutions of surface acoustic waves,in particular Rayleigh waves that depend on porosity for a mesoporous silicon layer.The velocities are obtained from different V(z) curves,which are determined experimentally at a frequency of 600MHz.The analysis of V(z) data yields attenuation that is directly dependent on porosity.On the other hand,αN attenuation has been modeled and allows us to investigate its influence on the velocity VR of the propagation for Rayleigh waves.%Using acoustic microscopy at higher frequency, we show the velocity evolutions of surface acoustic waves, in particular Rayleigh waves that depend on porosity for a mesoporous silicon layer. The velocities are obtained from different V(z) curves, which are determined experimentally at a frequency of 600 MHz. The analysis of V(z) data yields attenuation that is directly dependent on porosity. On the other hand, αN attenuation has been modeled and allows us to investigate its influence on the velocity VR of the propagation for Rayleigh waves.

  14. Characteristics of liver tissue for attenuate the gamma radiation

    International Nuclear Information System (INIS)

    It was determined the lineal attenuation coefficient of hepatic tissue before gamma radiation of a source of 137 Cs. When exposing organic material before X or gamma radiation fields, part of the energy of the photons is absorbed by the material, while another part crosses it without producing any effect. The quantity of energy that is absorbed is a measure of the dose that receives the material. The three main mechanisms by means of which the gamma rays interacting with the matter are: The Photoelectric Effect, the Compton dispersion and the Even production; the sum of these three processes is translated in the attenuation coefficient of the radiation. In this work we have used hepatic tissue of bovine, as substitute of the human hepatic tissue, and we have measured the lineal attenuation coefficient for photons of 0.662 MeV. Through a series of calculations we have determined the lineal attenuation coefficient for photons from 10-3 to 10-5 MeV and the measured coefficient was compared with the one calculated. (Author)

  15. 49 CFR 227.117 - Hearing protector attenuation.

    Science.gov (United States)

    2010-10-01

    ... ADMINISTRATION, DEPARTMENT OF TRANSPORTATION OCCUPATIONAL NOISE EXPOSURE Occupational Noise Exposure for Railroad Operating Employees. § 227.117 Hearing protector attenuation. (a) A railroad shall evaluate hearing... exposure to an 8-hour TWA of 90 decibels or lower, as required by § 227.115. (c) For employees who...

  16. 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 Oris

  17. Simultaneous amplification and attenuation in isotropic chiral materials

    CERN Document Server

    Mackay, Tom G

    2015-01-01

    The electromagnetic field phasors in an isotropic chiral material (ICM) are superpositions of two Beltrami fields of different handedness. Application of the Bruggeman homogenization formalism to two-component composite materials delivers ICMs wherein Beltrami fields of one handedness attenuate whereas Beltrami waves of the other handedness amplify. One component material is a dissipative ICM, the other an active dielectric material.

  18. 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

  19. 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...

  20. Soil temperature effect in calculating attenuation and retardation factors.

    Science.gov (United States)

    Paraiba, Lourival Costa; Spadotto, Claudio Aparecido

    2002-09-01

    The effect of annual variation of daily average soil temperature, at different depths, in calculating pesticides ranking indexes retardation factor and attenuation factor is presented. The retardation factor and attenuation factor are two site-specific pesticide numbers, frequently used as screening indicator indexes for pesticide groundwater contamination potential. Generally, in the calculation of these two factors are not included the soil temperature effect on the parameters involved in its calculation. It is well known that the soil temperature affects the pesticide degradation rate, water-air partition coefficient and water-soil partition coefficient. These three parameters are components of the retardation factor and attenuation factor and contribute to determine the pesticide behavior in the environment. The Arrhenius equation, van't Hoff equation and Clausius-Clapeyron equation are used in this work for estimating the soil temperature effect on the pesticide degradation rate, water-air partition coefficient and soil-water partition coefficient, respectively. These dependence relationships, between results of calculating attenuation and retardation factors and the soil temperature at different depths, can aid to understand the potential pesticide groundwater contamination on different weather conditions. Numerical results will be presented with pesticides atrazine and lindane in a soil profile with 20 degrees C constant temperature, minimum and maximum surface temperatures varying and spreading in the soil profile between -5 and 30 degrees C and between 15 and 45 degrees C. PMID:12222785

  1. Experimental determination of the lineal attenuation coefficient of ground

    International Nuclear Information System (INIS)

    This work reports the measurement of the linear attenuation coefficient of ground in order to elaborate a calculus memory for a nuclear medicine installation. The service is placed in the subsoil and the hot room is surrounded by variable, higher than a meter, thicknesses of ground. Owing to the lack of bibliography about the value of the linear attenuation coefficient of ground, we measured it and compared the result with that obtained by the density correction method relative to concrete, using the linear attenuation coefficient value of this material as derived from experimental measures of this material. Measurements were made using a BaF2 scintillation detector and a 137Cs source, which was selected considering the similitude between its energy and the energy of the radiopharmaceutical used in the service for the PET studies, 22Na. Different increasing thicknesses of ground got from areas located near the service were placed as absorbents. The work involves ten experimental points, interposing cumulatively 1.8cm thicknesses of ground each time, between the detector and the source. The results obtained from both methods do not present a significant difference, however, we have concluded that the measured coefficient is more appropriate that the one estimated by the density correction method. Consequently, for calculating the dose rates at different places of the service, the experimentally determined value μ = 0.0884 cm-1 of the linear attenuation coefficient was used. (author)

  2. Body Wave Crustal Attenuation Characteristics in the Garhwal Himalaya, India

    Science.gov (United States)

    Negi, Sanjay S.; Paul, Ajay; Joshi, Anand; Kamal

    2015-06-01

    We estimate frequency-dependent attenuation of P and S waves in Garhwal Himalaya using the extended coda normalization method for the central frequencies 1.5, 2, 3, 4, 6, 8, 10, 12, and 16 Hz, with earthquake hypocentral distance ranging from 27 to 200 km. Forty well-located local earthquake waveforms were used to study the seismic attenuation characteristics of the Garhwal Himalaya, India, as recorded by eight stations operated by Wadia Institute of Himalayan Geology, Dehradun, India, from 2007 to 2012. We find frequency-dependent P and S wave quality factors as defined by the relations Q P = 56 ± 8 f 0.91±0.002 and Q S = 151 ± 8 f 0.84±0.002 by fitting a power-law frequency dependence model for the estimated values over the whole region. Both the Q P and Q S values indicate strong attenuation in the crust of Garhwal Himalaya. The ratio of Q S/ Q P > 1 obtained for the entire analyzed frequency range suggests that the scattering loss is due to a random and high degree of heterogeneities in the earth medium, playing an important role in seismic wave attenuation in the Himalayan crust.

  3. NATURAL ATTENUATION OF COPPER IN SOILS AND SOIL MINERALS - I

    Science.gov (United States)

    The bioavailability and toxicity of Cu in soils is controlled by a number of soil properties and processes. Some of these such as pH, adsorption/desorption and competition with beneficial cations have been extensively studied. However, the effects of natural attenuation (or aging...

  4. NATURAL ATTENUATION OF COPPER IN SOILS AND SOIL MINERALS - II

    Science.gov (United States)

    The bioabailability and toxicity of Cu in soils is controlled by a number of soil properties and processes. Some of these such as pH, adsorption/desorption and competition with beneficial cations have been extensively studied. However, the effects of natural attenuation (or aging...

  5. Closed-Loop Control of MEMS Variable Optical Attenuator (VOA)

    Institute of Scientific and Technical Information of China (English)

    H. Cai; X. M. Zhang; A. Q. Liu; Y. X. Wang; C. Lu

    2003-01-01

    This paper reports the development of an optical power regulator based on surface-micromachined variable optical attenuators (VOAs). By use of closed-loop control circuits, each VOA module implements the functions of power setpoint tracking, disturbance rejection and ripple suppression.

  6. 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 Lg Q (Q0) values between many pairs of stations. Finally, 5 events with 70 high-quality inter-station paths were selected from 117 possible pairs of stations that are (1) aligned approximately with the source and (2) separated enough to permit the use of the standard two-station method for Lg Q measurement. Spatial variations in Q0 have been noticed across the Gujarat region. Low 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.

  7. Gamma ray attenuation in a developed borate glassy system

    Science.gov (United States)

    Saeed, Aly; El shazly, R. M.; Elbashar, Y. H.; Abou El-azm, A. M.; El-Okr, M. M.; Comsan, M. N. H.; Osman, A. M.; Abdal-monem, A. M.; El-Sersy, A. R.

    2014-09-01

    Measurements and calculations of gamma ray attenuation coefficients in glass barriers of xBaO-5ZnO-5MgO-14Na2O--1Li2O-(75-x)B2O3, previously prepared by the melt-quenching technique [1], were performed for γ-ray of energies 121.8, 244.7, 344.14, 661.66, 778.7, 974, 1086.7, 1173.24, 1332.5, and 1407.9 keV; which emitted from 152Eu, 137Cs, and 60Co radioactive gamma ray sources. The transmitted γ-rays were detected by 3″×3″ and 5″×5″ NaI (Tl) scintillation γ-ray spectrometers, and a highly calibrated survey meter. The mass attenuation coefficients of γ-rays (σ(E) were deduced from the attenuation curves, while the WinXCom computer program (version 3.1) was used to calculate the mass attenuation coefficients of γ-rays for such energies at different barium concentrations of a glassy system. A good agreement between both experimental and theoretical results was achieved as well as results obtained by other workers in similar field.

  8. Low-energy gamma ray attenuation characteristics of aviation fuels

    Science.gov (United States)

    Singh, Jag J.; Shen, Chih-Ping; Sprinkle, Danny R.

    1990-01-01

    Am241 (59.5 keV) gamma ray attenuation characteristics were investigated in 270 aviation fuel (Jet A and Jet A-1) samples from 76 airports around the world as a part of world wide study to measure the variability of aviation fuel properties as a function of season and geographical origin. All measurements were made at room temperature which varied from 20 to 27 C. Fuel densities (rho) were measured concurrently with their linear attenuation coefficients (mu), thus providing a measure of mass attenuation coefficient (mu/rho) for the test samples. In 43 fuel samples, rho and mu values were measured at more than one room temperature, thus providing mu/rho values for them at several temperatures. The results were found to be independent of the temperature at which mu and rho values were measured. It is noted that whereas the individual mu and rho values vary considerably from airport to airport as well as season to season, the mu/rho values for all samples are constant at 0.1843 + or - 0.0013 cu cm/gm. This constancy of mu/rho value for aviation fuels is significant since a nuclear fuel quantity gauging system based on low energy gamma ray attenuation will be viable throughout the world.

  9. Low temperature attenuation of sound in restricted geometries

    OpenAIRE

    Lambert, B.; Salin, D.

    1980-01-01

    We have measured the low temperature attenuation of sound at 1 GHz in liquid helium confined in the pores of Vycor glass; our data clearly show the one-dimensional behaviour of the normal density in this restricted geometry; the experimental value is in agreement with fourth sound measurements; anyway the experimental values are three orders of magnitude larger than the theoretical one.

  10. Attenuation of ground vibrations due to different technical sources

    Science.gov (United States)

    Auersch, L.; Said, S.

    2010-09-01

    The attenuation of technically induced surface waves is studied theoretically and experimentally. In this paper, nineteen measurements of ground vibrations induced by eight different technical sources including road and rail traffic, vibratory and impulsive construction work or pile driving, explosions, hammer impulses and mass drops are described, and it is shown that the technically induced ground vibrations exhibit a power-law attenuation v ˜ r - q where the exponents q are in the range of 0.5 to 2.0 and depend on the source types. Comparisons performed demonstrate that the measured exponents are considerably higher than theoretically expected. Some potential effects on ground vibration attenuation are theoretically analyzed. The most important effect is due to the material or scattering damping. Each frequency component is attenuated exponentially as exp(- kr), but for a broad-band excitation, the sum of the exponential laws also yields a power law but with a high exponent. Additional effects are discussed, for example the dispersion of the Rayleigh wave due to soil layering, which yields an additional exponent of 0.5 in cases of impulsive loading.

  11. Attenuation of ground vibrations due to different technical sources

    Institute of Scientific and Technical Information of China (English)

    L. Auersch; S. Said

    2010-01-01

    The attenuation of technically induced surface waves is studied theoretically and experimentally. In this paper, nineteen measurements of ground vibrations induced by eight different technical sources including road and rail traffic, vibratory and impulsive construction work or pile driving, explosions, hammer impulses and mass drops are described, and it is shown that the technically induced ground vibrations exhibit a power-law attenuation v ~ r where the exponents q are in the range of 0.5 to 2.0 and depend on the source types. Comparisons performed demonstrate that the measured exponents are considerably higher than theoretically expected. Some potential effects on ground vibration attenuation are theoretically analyzed. The most important effect is due to the material or scattering damping. Each frequency component is attenuated exponentially as exp(-kr), but for a broad-band excitation, the sum of the exponential laws also yields a power law but with a high exponent. Additional effects are discussed, for example the dispersion of the Rayleigh wave due to soil layering, which yields an additional exponent of 0.5 in cases of impulsive loading.

  12. 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.

  13. PAUT inspection of copper canister: Structural attenuation and POD formulation

    Science.gov (United States)

    Gianneo, A.; Carboni, M.; Mueller, C.; Ronneteg, U.

    2016-02-01

    For inspection of thick-walled (50mm) copper canisters for final disposal of spent nuclear fuel in Sweden, ultrasonic inspection using phased array technique (PAUT) is applied. Because thick-walled copper is not commonly used as a structural material, previous experience on Phased Array Ultrasonic Testing for this type of application is limited. The paper presents the progress in understanding the amplitudes and attenuation changes acting on the Phased Array Ultrasonic Testing inspection of copper canisters. Previous studies showed the existence of a low pass filtering effect and a heterogeneous grain size distribution along the depth, thus affecting both the detectability of defects and their "Probability of Detection" determination. Consequently, the difference between the first and second back wall echoes were not sufficient to determine the local attenuation (within the inspection range), which affects the signal response for each individual defect. Experimental evaluation of structural attenuation was carried out onto step-wedge samples cut from full-size, extruded and pierced & drawn, copper canisters. Effective attenuation values has been implemented in numerical simulations to achieve a Multi Parameter Probability of Detection and to formulate a Model Assisted Probability of Detection through a Monte-Carlo extraction model.

  14. Attenuation law of seismic waves in technical seismicity

    OpenAIRE

    B. Pandula; J. Kondela; K. Pachocka

    2012-01-01

    Blasting operations have positive and negative effects as well. Vibration intensity and seismic safety associated to the blasting operations are highly actual and challenging problem. The presented article describes the results of the analysis and the methodology of evaluation of objects` seismic safety during blasting operations by application of attenuation law of the seismic waves.

  15. Laboratory measurements of seismic attenuation in partially saturated rocks

    Science.gov (United States)

    Chapman, Samuel; Tisato, Nicola; Quintal, Beatriz; Holliger, Klaus

    2014-05-01

    Laboratory measurements of seismic attenuation and transient pore fluid pressure are performed on partially saturated Berea sandstone and synthetic borosilicate samples. Various degrees of water (liquid) and nitrogen (gas) saturation are considered. These measurements are carried out at room temperature and under confining pressures varying from ambient conditions up to 25 MPa. The cylindrical samples are 25 cm long and have a diameter of 7.6 cm. In the context of the experimental setup, the solid frames of both the Berea sandstone and the borosilicate samples can be considered homogenous, which in turn allows for isolating and exploring the effects of partial saturation on seismic attenuation. We employ the sub-resonance method, which is based on the application of a time-harmonic vertical stress to the top of the sample and the measurement of the thus resulting strain. For any given frequency, the attenuation is then inferred as the tangent of the phase shift between the applied stress and the observed strain. Using five equally spaced sensors along the central axis of the cylindrical sample, we measure the transient fluid pressure induced by the application of a step-function-type vertical stress to the top of the sample. Both the sensors and the sample are sealed off with the regard to the confining environment. Together with the numerical results from corresponding compressibility tests based on the quasi-static poroelastic equations, these transient fluid pressure measurements are then used to assist the interpretation of the seismic attenuation measurements.

  16. Modeling transmission and scatter for photon beam attenuators.

    Science.gov (United States)

    Ahnesjö, A; Weber, L; Nilsson, P

    1995-11-01

    The development of treatment planning methods in radiation therapy requires dose calculation methods that are both accurate and general enough to provide a dose per unit monitor setting for a broad variety of fields and beam modifiers. The purpose of this work was to develop models for calculation of scatter and transmission for photon beam attenuators such as compensating filters, wedges, and block trays. The attenuation of the beam is calculated using a spectrum of the beam, and a correction factor based on attenuation measurements. Small angle coherent scatter and electron binding effects on scattering cross sections are considered by use of a correction factor. Quality changes in beam penetrability and energy fluence to dose conversion are modeled by use of the calculated primary beam spectrum after passage through the attenuator. The beam spectra are derived by the depth dose effective method, i.e., by minimizing the difference between measured and calculated depth dose distributions, where the calculated distributions are derived by superposing data from a database for monoenergetic photons. The attenuator scatter is integrated over the area viewed from the calculation point of view using first scatter theory. Calculations are simplified by replacing the energy and angular-dependent cross-section formulas with the forward scatter constant r2(0) and a set of parametrized correction functions. The set of corrections include functions for the Compton energy loss, scatter attenuation, and secondary bremsstrahlung production. The effect of charged particle contamination is bypassed by avoiding use of dmax for absolute dose calibrations. The results of the model are compared with scatter measurements in air for copper and lead filters and with dose to a water phantom for lead filters for 4 and 18 MV. For attenuated beams, downstream of the buildup region, the calculated results agree with measurements on the 1.5% level. The accuracy was slightly less in situations

  17. Modeling transmission and scatter for photon beam attenuators.

    Science.gov (United States)

    Ahnesjö, A; Weber, L; Nilsson, P

    1995-11-01

    The development of treatment planning methods in radiation therapy requires dose calculation methods that are both accurate and general enough to provide a dose per unit monitor setting for a broad variety of fields and beam modifiers. The purpose of this work was to develop models for calculation of scatter and transmission for photon beam attenuators such as compensating filters, wedges, and block trays. The attenuation of the beam is calculated using a spectrum of the beam, and a correction factor based on attenuation measurements. Small angle coherent scatter and electron binding effects on scattering cross sections are considered by use of a correction factor. Quality changes in beam penetrability and energy fluence to dose conversion are modeled by use of the calculated primary beam spectrum after passage through the attenuator. The beam spectra are derived by the depth dose effective method, i.e., by minimizing the difference between measured and calculated depth dose distributions, where the calculated distributions are derived by superposing data from a database for monoenergetic photons. The attenuator scatter is integrated over the area viewed from the calculation point of view using first scatter theory. Calculations are simplified by replacing the energy and angular-dependent cross-section formulas with the forward scatter constant r2(0) and a set of parametrized correction functions. The set of corrections include functions for the Compton energy loss, scatter attenuation, and secondary bremsstrahlung production. The effect of charged particle contamination is bypassed by avoiding use of dmax for absolute dose calibrations. The results of the model are compared with scatter measurements in air for copper and lead filters and with dose to a water phantom for lead filters for 4 and 18 MV. For attenuated beams, downstream of the buildup region, the calculated results agree with measurements on the 1.5% level. The accuracy was slightly less in situations

  18. Three-dimensional attenuation structure beneath North Island, New Zealand

    Science.gov (United States)

    Satake, Kenji; Hashida, Toshihiko

    1989-03-01

    Three-dimensional attenuation structure beneath North Island, New Zealand is determined by inversion of seismic intensity data. The method developed by Hashida and Shimazaki is used; the seismic intensity is converted to the maximum acceleration of the S-wave to obtain the acceleration at a point source and the attenuation structure. Because seismic intensity data have been accumulated on a uniform scale in New Zealand since the 1950's, we were able to use more than 2000 seismic intensity data from 26 earthquakes. The results show a remarkable contrast in the attenuation structure. In the top crustal layer, a low-Q area corresponding to the Central Volcanic Region is found. This low-Q area becomes wider to the northeast of North Island, suggesting that the Central Volcanic Region continues to the Havre Trough, a young back-arc basin. The southeastern part of the upper mantle beneath North Island shows high Q while the northwestern part shows low Q. The cross section shows that the high-Q region is dipping to the northwest, with a large amount of dip in the northeast and a smaller dip in the southwestern part of North Island. A comparison of the attenuation structure with microearthquake distribution indicates that this high-Q zone is the obliquely subducting Pacific plate. A zone of abnormally low Q which has cut the high-Q slab is found at a depth range of 130 to 230 km beneath the active volcanoes in the Taupo Volcanic Zone. A tear in the Pacific plate is suggested by this discontinuity in the attenuation structure. (1984).

  19. IRON PRECIPITATION AND ARSENIC ATTENUATION - ASSESSMENT OF ARSENIC NATURAL ATTENUATION OF THE SUBSURFACE USING A GEOCHEMICAL MODEL (PHREEQC)

    Science.gov (United States)

    Laboratory experiments show that amorphous and poorly crystallized ferric iron hydroxides have much greater capacity to attenuate arsenic compared to clays and other aluminosilicate minerals. Studies (e.g., Lin and Qvarfort, 1996) showed that a sudden change in geochemical condit...

  20. 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.

    2013-01-01

    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 co

  1. CT-based attenuation and scatter correction compared with uniform attenuation correction in brain perfusion SPECT imaging for dementia

    Science.gov (United States)

    Gillen, Rebecca; Firbank, Michael J.; Lloyd, Jim; O'Brien, John T.

    2015-09-01

    This study investigated if the appearance and diagnostic accuracy of HMPAO brain perfusion SPECT images could be improved by using CT-based attenuation and scatter correction compared with the uniform attenuation correction method. A cohort of subjects who were clinically categorized as Alzheimer’s Disease (n=38 ), Dementia with Lewy Bodies (n=29 ) or healthy normal controls (n=30 ), underwent SPECT imaging with Tc-99m HMPAO and a separate CT scan. The SPECT images were processed using: (a) correction map derived from the subject’s CT scan or (b) the Chang uniform approximation for correction or (c) no attenuation correction. Images were visually inspected. The ratios between key regions of interest known to be affected or spared in each condition were calculated for each correction method, and the differences between these ratios were evaluated. The images produced using the different corrections were noted to be visually different. However, ROI analysis found similar statistically significant differences between control and dementia groups and between AD and DLB groups regardless of the correction map used. We did not identify an improvement in diagnostic accuracy in images which were corrected using CT-based attenuation and scatter correction, compared with those corrected using a uniform correction map.

  2. 棉花黄萎病原真菌菌体对链霉菌4种胞外水解酶活性的影响%Influence of Verticillium dahliae mycelium on 4 types of extracellular hydrolases activity of Streptomyces

    Institute of Scientific and Technical Information of China (English)

    薛磊; 薛泉宏; 卢建军; 申光辉; 赵娟

    2012-01-01

    The inhibitory effect of antagonistic Streptomyces on Verticillium dahliae Kleb. via enzymatic hy-drolysis was studied. The pathogen mycelia were used as the sole carbon source, induced effect of V. dahliae on extracellular hydrolases synthesis by 4 tested Streptomyces in liquid cultures was examined; and interaction between Streptomyces and V. dahliae hypha via hydrolysis of aerial mycelium and microscopy were observed. The results showed that synthesis of extracellular chitinase, β-1,3-glucosidase, β-glucosidase and FP cellulase was induced by tested Streptomyces in the presence of V. dahliae. Optimal conditions for extracellular hydro-lases fermentation of 4 Streptomyces were related to addition of 10 g·L-1 fungi mycelium at 281 for 7 d. The activities of associated extracellular hydrolases were 70.13 -129.05, 31.04 -37.34, 6.24 -8.75 and 1. 84-3.35 U, respectively. Streptomyce crude enzyme solution induced disintegration of V. dahliaemycelia and hypha. All 4 Streptomyces were found capable of twining with V. dahliae hypha, leading to fungal cell wall lysis.%以大丽轮枝菌(Verticillium dahliae Kleb.)菌体为唯一碳源,采用液体培养法测定供试病原菌菌体对4株拮抗链霉菌胞壁水解酶合成的诱导作用;采用平皿气生菌丝水解和显微观察法验证4株拮抗链霉菌对大丽轮枝菌菌丝的溶解作用.结果表明:①大丽轮枝菌菌体可以诱导供试链霉菌合成几丁质酶、β-1,3-葡聚糖酶、β-葡萄糖苷酶及滤纸纤维素酶;当菌体添加量为10 g·L-1,28℃培养7d时,上述4种诱导酶活性可达峰值,其值分别为70.13-129.05、31.04-37.34、6.24-8.75及1.84-3.35 U.②链霉菌粗酶液对大丽轮枝菌菌丝有溶解作用.③4株链霉菌菌丝均可缠绕在大丽轮枝菌菌丝上,并在缠绕处使病原菌菌丝溶解.

  3. 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

  4. PREPARATION AND MICROWAVE ATTENUATION PROPERTY IN THE X BAND OF SiC–C COMPOSITES

    Directory of Open Access Journals (Sweden)

    ZEHUA ZHOU

    2011-02-01

    Full Text Available For developing an effective, low-cost method on preparation of microwave attenuation material, SiC–C composites with different additions of graphite grain were fabricated with solid phase sintering and liquid phase sintering, respectively. The microwave attenuation and the relative electrical properties of composites in the X band were measured. The results show that both methods are cost-effective and easily controllable processes and Solid phase sintering was more suitable to obtain SiC-C attenuation composites than the liquid phase sintering. The composite with 3 wt.% C prepared by solid phase sintering exhibited the best microwave attenuation, the biggest attenuation was -40.5 dB and most attenuations were above -30 dB in the whole X band. Furthermore, the microwave attenuation of composites depended strongly on the C additions; Match of interface of wave impedance and high wave consumption are both necessary for microwave attenuation materials.

  5. Measurment and Interpretation of Seismic Attenuation for Hydrocarbon Exploration

    Energy Technology Data Exchange (ETDEWEB)

    Michael Batzle; Luca Duranti; James Rector; Steve Pride

    2007-12-31

    This research project is the combined effort of several leading research groups. Advanced theoretical work is being conducted at the Lawrence Berkeley National Laboratory. Here, the fundamental controls on loss mechanisms are being examined, primarily by use of numerical models of heterogeneous porous media. At the University of California, Berkeley, forward modeling is combined with direct measurement of attenuation. This forward modeling provides an estimate of the influence of 1/Q on the observed seismic signature. Direct measures of losses in Vertical Seismic Profiles (VSPs) indicate mechanisms to separate scattering versus intrinsic losses. At the Colorado School of Mines, low frequency attenuation measurements are combined with geologic models of deep water sands. ChevronTexaco is our corporate cosponsor and research partner. This corporation is providing field data over the Genesis Field, Gulf of Mexico. In addition, ChevronTexaco has rebuilt and improved their low frequency measurement system. Soft samples representative of the Genesis Field can now be measured for velocities and attenuations under reservoir conditions. Throughout this project we have: Assessed the contribution of mechanical compaction on time-lapse monitoring; Developed and tested finite difference code to model dispersion and attenuation; Heterogeneous porous materials were modeled and 1/Q calculated vs. frequency; 'Self-affine' heterogeneous materials with differing Hurst exponent modeled; Laboratory confirmation was made of meso-scale fluid motion influence on 1/Q; Confirmed theory and magnitude of layer-based scattering attenuation at Genesis and at a shallow site in California; Scattering Q's of between 40 and 80 were obtained; Measured very low intrinsic Q's (2-20) in a partially saturated vadose zone VSP; First field study to separate scattering and intrinsic attenuation in real data set; Revitalized low frequency device at ChevronTexaco's Richmond lab

  6. 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.

  7. Estimation of compressional seismic wave attenuation of carbonate rocks in Abu Dhabi, United Arab Emirates

    Science.gov (United States)

    Bouchaala, Fateh; Ali, Mohammed Y.; Farid, Asam

    2014-07-01

    The subsurface geology of Abu Dhabi in the United Arab Emirates is primarily composed of carbonate rocks. Such media are known to be highly heterogeneous. Very few studies have attempted to estimate attenuation in carbonate rocks. In Abu Dhabi no attenuation profile has been published. This study provides the first seismic wave attenuation profiles in Abu Dhabi using dense array of VSP data. We estimated three attenuation profiles: the apparent, the scattering, and the intrinsic attenuations. The apparent attenuation profile was computed using amplitude decay and spectral-ratio methods. The scattering attenuation profile was estimated using a generalized reflection-transmission matrix forward model. It is usually estimated from the sonic log, but to be more consistent with the apparent attenuation, we succeeded in this paper to estimate it from the VSP data. We subtracted the scattering attenuation from the apparent attenuation to deduce the intrinsic attenuation. The results of the study indicate that the scattering attenuation is significant compared to the published studies that are mainly based on clastic rocks. The high scattering attenuation can reach up to 0.02. It can be explained by the strong heterogeneity of the carbonate rocks. This study demonstrates that the Simsima and Rus Formations have considerable scattering and intrinsic attenuations. These formations are considered aquifers in Abu Dhabi; we therefore interpreted this high intrinsic attenuation zones to be due to the heterogeneity and to the fluids contained in these formations. The Umm-Er-Radhuma Formation is a more homogenous formation with limited aquifer potential. Hence, scattering and intrinsic attenuations of the Umm-Er-Radhuma Formation are low.

  8. Wave attenuation model for dephasing and measurement of conditional times

    Indian Academy of Sciences (India)

    A M Jayannavar; Colin Benjamin

    2002-08-01

    Inelastic scattering induces dephasing in mesoscopic systems. An analysis of previous models to simulate inelastic scattering in such systems is presented and a relatively new model based on wave attenuation is introduced. The problem of Aharonov–Bohm (AB) oscillations in conductance of a mesoscopic ring is studied. We show that the conductance is symmetric under flux reversal and the visibility of AB oscillations decays to zero as a function of the incoherence parameter, signaling dephasing. Further the wave attenuation model is applied to a fundamental problem in quantum mechanics, that of the conditional (reflection/transmission) times spent in a given region of space by a quantum particle before scattering off from that region.

  9. Experimental and theoretical studies on visible light attenuation in water

    CERN Document Server

    Simpson, A; Cho, H J; Liu, H

    2014-01-01

    In this study we describe lab experiments on determining the above water reflectance Rrs coefficient, and the water attenuation coefficient Kd for fresh water. Different types of screens (totally absorbent, gray, etc.) were submerged in water (0-0.6 m) and illuminated from outside. The spectral density of the water leaving radiance was measured for different depths. The results were ran by a code which took into account the geometry of the incident irradiation, the geometry of the screen under water, and boundary conditions at the water surface provided by the radiation transfer theory. From the experimental data and our model we obtain the spectral distribution of the attenuation coefficient for fresh water and compared it with other data in literature. These experiments, performed in the Nonlinear Wave Lab at ERAU# represent just a preliminary calibration of the experimental protocol. More tests with water of different degrees of turbidity, and possibly wave filed at the water surface are in progress and wi...

  10. Attenuation of earthquake generated P waves in Iraq

    International Nuclear Information System (INIS)

    This work is the first attempt to investigate seismic wave attenuation in Iraq. it studies longitudinal waves recorded at Baghdad (BHD) and Musul (MSL) observatories from earthquakes originated in Turkey and in Iran. Thirty seven earthquakes were chosen for this investigation, twenty three of them were recorded at Baghdad observatory, and fourteen were recorded at Mousul observatory. The epicenters of some of these earthquakes are located within the Iraqi territory; the rest of the events have their epicenters on the Iraqi-Iran borders or on the Turkish and Iranian sides of the boeder. The path of the investigated earthquakes cover the central, north and eastern regions of Iraq; with magnitudes (mb) varying between (4.1-5.7). The amplitude-distance curve method was utilized in this investigation. The mean attenuation value obtained for the study area was 0.0035 km-1. (authors). 19 refs., 7 tabs., 9 figs

  11. 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

  12. Electroacupuncture attenuates neuropathic pain after brachial plexus injury

    Institute of Scientific and Technical Information of China (English)

    Shenyu Zhang; Hailiang Tang; Junming Zhou; Yudong Gu

    2014-01-01

    Electroacupuncture has traditionally been used to treat pain, but its effect on pain following brachial plexus injury is still unknown. In this study, rat models of an avulsion injury to the left brachial plexus root (associated with upper-limb chronic neuropathic pain) were given electroacu-puncture stimulation at bilateralQuchi(LI11),Hegu(LI04),Zusanli(ST36) andYanglingquan (GB34). After electroacupuncture therapy, chronic neuropathic pain in the rats’ upper limbs was signiifcantly attenuated. Immunolfuorescence staining showed that the expression of β-endorphins in the arcuate nucleus was signiifcantly increased after therapy. Thus, experimental ifndings indi-cate that electroacupuncture can attenuate neuropathic pain after brachial plexus injury through upregulatingβ-endorphin expression.

  13. 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.

  14. Attenuation of vacuum ultraviolet light in liquid argon

    CERN Document Server

    Neumeier, A; Oberauer, L; Potzel, W; Schönert, S; Dandl, T; Heindl, T; Ulrich, A; Wieser, J

    2015-01-01

    The transmission of liquid argon has been measured, wavelength resolved, for a wavelength interval from 118 to 250 nm. The wavelength dependent attenuation length is presented for pure argon. It is shown that no universal wavelength independent attenuation length can be assigned to liquid argon for its own fluorescence light due to the interplay between the wavelength dependent emission and absorption. A decreasing transmission is observed below 130 nm in both chemically cleaned and distilled liquid argon and assigned to absorption by the analogue of the first argon excimer continuum. For not perfectly cleaned argon a strong influence of impurities on the transmission is observed. Two strong absorption bands at 126.5 and 141.0 nm with approximately 2 and 4 nm width, respectively, are assigned to traces of xenon in argon. A broad absorption region below 180 nm is found for unpurified argon and tentatively attributed to the presence of water in the argon sample.

  15. 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 ...

  16. Signal Attenuation Curve for Different Surface Detector Arrays

    CERN Document Server

    Vicha, J; Nosek, D; Ebr, J

    2014-01-01

    Modern cosmic ray experiments consisting of large array of particle detectors measure the signals of electromagnetic or muon components or their combination. The correction for an amount of atmosphere passed is applied to the surface detector signal before its conversion to the shower energy. Either Monte Carlo based approach assuming certain composition of primaries or indirect estimation using real data and assuming isotropy of arrival directions can be used. Toy surface arrays of different sensitivities to electromagnetic and muon components are assumed in MC simulations to study effects imposed on attenuation curves for varying composition or possible high energy anisotropy. The possible sensitivity of the attenuation curve to the mass composition is also tested for different array types focusing on a future apparatus that can separate muon and electromagnetic component signals.

  17. Anatomy of the TAMA SAS seismic attenuation system

    International Nuclear Information System (INIS)

    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 ∼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

  18. Wave Dispersion and Attenuation in Partially Saturated Sandstones

    Institute of Scientific and Technical Information of China (English)

    NIE Jian-Xin; YANG Ding-Hui; YANG Hui-Zhu

    2004-01-01

    @@ We investigate the wave dispersion and attenuation in partially water-saturated sandstones based on the improved Biot/squirt (BISQ) model in which the saturation is introduced. Numerical experiments indicate that the phase velocity of the fast P-wave decreases as the saturation increases in the low-frequency range (102-104 Hz), and reaches the minimum at the full-saturation state. The behaviour of the phase velocity varying with the saturation in the high-frequency range (104-106 Hz), however, is opposite to that in the low-frequency range. The peak value of P-wave attenuation increases with increasing saturation, and is the maximum at the fully saturated state. Numerical models and experiments show that the improved BISQ model is better than the traditional Gassmann-Biot model.

  19. 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.

  20. Sustainability of natural attenuation of nitrate in agricultural aquifers

    Science.gov (United States)

    Green, Christopher T.; Bekins, Barbara A.

    2010-01-01

    Increased concentrations of nitrate in groundwater in agricultural areas, coinciding with increased use of chemical and organic fertilizers, have raised concern because of risks to environmental and human health. At some sites, these problems are mitigated by natural attenuation of nitrate as a result of microbially mediated reactions. Results from U.S. Geological Survey (USGS) research under the National Water-Quality Assessment (NAWQA) program show that reactions of dissolved nitrate with solid aquifer minerals and organic carbon help lower nitrate concentrations in groundwater beneath agricultural fields. However, increased fluxes of nitrate cause ongoing depletion of the finite pool of solid reactants. Consumption of the solid reactants diminishes the capacity of the aquifer to remove nitrate, calling into question the long-term sustainability of these natural attenuation processes.

  1. Design and Simulation of Microwave Attenuators for Superconducting Quantum Devices

    Science.gov (United States)

    Lefebvre, Jay; Yeh, Jen-Hao; Wellstood, Frederick; Palmer, Benjamin

    We have found that dephasing times for quantum superconducting transmons operating nominally at T = 20 mK can be limited by thermal photons in the read-out cavity due to non-equilibrium noise on our input microwave line. In an effort to reduce this noise, we have used finite-element simulations to design attenuators that provide better thermalization of the input microwave signals being delivered to our devices. Our thermal simulations incorporate both electron-phonon decoupling effects due to dissipated power in each element of the attenuator as well as phonon thermal conduction and Kapitza boundary effects. We combine the resulting thermal map with a thermal noise model of each dissipative element of the filter to estimate the effective noise temperature of our filter design.

  2. Is Necessary Attenuation Correction for Cat Brain PET?

    International Nuclear Information System (INIS)

    Photon attenuation and scatter corrections (AC and SC) were necessary for quantification of human PET. However, there is no consensus on whether AC and SC are necessary for the cat brain PET imaging. Since post-injection transmission (TX) PET scans are not permitted or provided to microPET scanner users at present, additional time for performing TX scan and awaiting FDG uptake is required for attenuation and scatter corrections. Increasing probability of subject movement and possible biological effect of long term anesthesia would be the problem in additional TX scan. The aim of this study was to examine the effect of AC and SC for the quantification of cat brain PET data

  3. NATURAL ATTENUATION FOR ECOSYSTEM RESTORATION IN NY/NJ HARBOR

    Energy Technology Data Exchange (ETDEWEB)

    Van der Lelie, D.; Reid-Green, J. D.; Stern, E. A.

    2003-12-31

    We have investigated the feasibility of using natural attenuation methods for ecosystem restoration in New York/New Jersey Harbor. Measurements were made of the most probable number of sulfate-reducing bacteria (SRB) in native sediments and in samples, which had been supplemented with an appropriate electron donor and electron acceptor. The results showed that the activity of the endogenous microbial population in the native sediment was high enough to make possible adequate chemical transformation rates. The bioavailability of the zinc in the sediments was measured using the BIOMET biosensor technique. The bioavailability of the zinc was effectively eliminated following the microbial activities. We concluded that natural attenuation could be used effectively in treating sediments from Newark Bay and surrounding waters and that the resultant materials could likely be used in environmental restoration projects of the type proposed for construction in South Kearny, NJ.

  4. Cognitive, Medical, and Neuroimaging Characteristics of Attenuated Mucopolysaccharidosis Type II

    OpenAIRE

    Yund, Brianna; Rudser, Kyle; Ahmed, Alia; Kovac, Victor; Nestrasil, Igor; Raiman, Julian; Mamak, Eva; Harmatz, Paul; Steiner, Robert; Lau, Heather; Vekaria, Pooja; Wozniak, Jeffrey R.; Lim, Kelvin O.; Delaney, Kathleen; Whitley, Chester

    2014-01-01

    The phenotype of attenuated mucopolysaccharidosis type II (MPS II), also called Hunter syndrome, has not been previously studied in systematic manner. In contrast to the “severe” phenotype, the “attenuated” phenotype does not present with behavioral or cognitive impairment; however the presence of mild behavior and cognitive impairment that might impact long term functional outcomes is unknown. Previously, significant MRI abnormalities have been found in MPS II. Recent evidence suggests white...

  5. Cognitive, Medical, and Neuroimaging Characteristics of Attenuated Mucopolysaccharidosis Type II

    Science.gov (United States)

    Yund, Brianna; Rudser, Kyle; Ahmed, Alia; Kovac, Victor; Nestrasil, Igor; Raiman, Julian; Mamak, Eva; Harmatz, Paul; Steiner, Robert; Lau, Heather; Vekaria, Pooja; Wozniak, Jeffrey R.; Lim, Kelvin O.; Delaney, Kathleen; Whitley, Chester; Shapiro, Elsa G.

    2014-01-01

    The phenotype of attenuated mucopolysaccharidosis type II (MPS II), also called Hunter syndrome, has not been previously studied in systematic manner. In contrast to the “severe” phenotype, the “attenuated” phenotype does not present with behavioral or cognitive impairment; however the presence of mild behavior and cognitive impairment that might impact long term functional outcomes is unknown. Previously, significant MRI abnormalities have been found in MPS II. Recent evidence suggests white matter abnormalities in many MPS disorders. Methods As the initial cross-sectional analysis of a longitudinal study, we studied the association of brain volumes and somatic disease burden with neuropsychological outcomes, including measures of intelligence, memory and attention in 20 patients with attenuated MPS II with a mean age of 15.8. MRI volumes were compared to 55 normal controls. Results While IQ and memory were average, measures of attention were one standard deviation below the average range. Corpus callosum volumes were significantly different from age-matched controls, differing by 22%. Normal age-related volume increases in white matter were not seen in MPS II patients as they were in controls. Somatic disease burden and white matter and corpus callosum volumes were significantly associated with attention deficits. Neither age at evaluation nor age at starting treatment predicted attention outcomes. Conclusions Despite average intelligence, attention is compromised in attenuated MPS II. Results confirm an important role of corpus callosum and cortical white matter abnormality in MPS II as well as the somatic disease burden in contributing to attention difficulties. Awareness by the patient and caregivers with appropriate management and symptomatic support will benefit the attenuated MPS II patient. PMID:25541100

  6. Interlaboratory comparison of radiation-induced attenuation in optical fibers

    Energy Technology Data Exchange (ETDEWEB)

    Friebele, E.J.; Lyons, P.B.; Blackburn, J.C.; Henschel, H.; Johan, A.; Krinsky, J.A.; Robinson, A.; Schneider, W.; Smith, D.; Taylor, E.W. (Naval Research Lab., Washington, DC (USA); Los Alamos National Lab., NM (USA); Harry Diamond Labs., Adelphi, MD (USA); Fraunhofer-Institut fuer Naturwissenschaftlich-Technische Trendanalysen (INT), Euskirchen (Germany, F.R.); Direction des Recherches, Etudes et Techni

    1989-08-01

    A comparison of the losses induced in step index multimode, graded index multimode and single mode fibers by pulsed radiation exposure has been made among 12 laboratories over a period of 5 years. The recoveries of the incremental attenuations from 10{sup -9} to 10{sup 1} s are reported. Although a standard set of measurement parameters was attempted, differences between the laboratories are evident; possible origins for these are discussed. 18 refs., 18 figs., 7 tabs.

  7. Wave attenuation in partially filled unsteady pipe flow

    OpenAIRE

    Abd El-Baky Mohamed, Nagwa

    1989-01-01

    This thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University. Much research activity is carried out to reduce water consumption for domestic purposes. This leads to the possibility of reducing the amount of water introduced into building drainage systems. However, an accurate estimation of the flow attenuation within building drainage pipes is of great importance to prevent solid eposition and subsequent blockage. The research is focused on the fiel...

  8. 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%).

  9. Enhancing lysosome biogenesis attenuates BNIP3-induced cardiomyocyte death

    OpenAIRE

    Ma, Xiucui; Godar, Rebecca J.; Liu, Haiyan; Diwan, Abhinav

    2012-01-01

    Hypoxia-inducible pro-death protein BNIP3 (BCL-2/adenovirus E1B 19-kDa interacting protein 3), provokes mitochondrial permeabilization causing cardiomyocyte death in ischemia-reperfusion injury. Inhibition of autophagy accelerates BNIP3-induced cell death, by preventing removal of damaged mitochondria. We tested the hypothesis that stimulating autophagy will attenuate BNIP3-induced cardiomyocyte death. Neonatal rat cardiac myocytes (NRCMs) were adenovirally transduced with BNIP3 (or LacZ as c...

  10. 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...

  11. Effects of impurities on particle sizing by acoustic attenuation spectroscopy

    OpenAIRE

    Inam, Muhammad Asif; Frances, Christine

    2010-01-01

    It is important to have correct information regarding particle size in order to interpret, control, and optimize many industrial processes. Prior to the recent advent of acoustic attenuation spectroscopy, it was difficult to study particle size distribution online and under real process conditions in processes involving concentrated dispersions (suspensions or emulsions). The technique still needs improvement because it is less known how and under which conditions to employ the technique when...

  12. Arsenic cycling in hydrocarbon plumes: secondary effects of natural attenuation

    Science.gov (United States)

    Cozzarelli, Isabelle M.; Schreiber, Madeline E.; Erickson, Melinda L.; Ziegler, Brady A.

    2016-01-01

    Monitored natural attenuation is widely applied as a remediation strategy at hydrocarbon spill sites. Natural attenuation relies on biodegradation of hydrocarbons coupled with reduction of electron acceptors, including solid phase ferric iron (Fe(III)). Because arsenic (As) adsorbs to Fe-hydroxides, a potential secondary effect of natural attenuation of hydrocarbons coupled with Fe(III) reduction is a release of naturally occurring As to groundwater. At a crude-oil-contaminated aquifer near Bemidji, Minnesota, anaerobic biodegradation of hydrocarbons coupled to Fe(III) reduction has been well documented. We collected groundwater samples at the site annually from 2009 to 2013 to examine if As is released to groundwater and, if so, to document relationships between As and Fe inside and outside of the dissolved hydrocarbon plume. Arsenic concentrations in groundwater in the plume reached 230 µg/L, whereas groundwater outside the plume contained less than 5 µg/L As. Combined with previous data from the Bemidji site, our results suggest that (1) naturally occurring As is associated with Fe-hydroxides present in the glacially derived aquifer sediments; (2) introduction of hydrocarbons results in reduction of Fe-hydroxides, releasing As and Fe to groundwater; (3) at the leading edge of the plume, As and Fe are removed from groundwater and retained on sediments; and (4) downgradient from the plume, patterns of As and Fe in groundwater are similar to background. We develop a conceptual model of secondary As release due to natural attenuation of hydrocarbons that can be applied to other sites where an influx of biodegradable organic carbon promotes Fe(III) reduction.

  13. 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.

  14. 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.

  15. The Attribute for Hydrocarbon Prediction Based on Attenuation

    Science.gov (United States)

    Hermana, Maman; Harith, Z. Z. T.; Sum, C. W.; Ghosh, D. P.

    2014-03-01

    Hydrocarbon prediction is a crucial issue in the oil and gas industry. Currently, the prediction of pore fluid and lithology are based on amplitude interpretation which has the potential to produce pitfalls in certain conditions of reservoir. Motivated by this fact, this work is directed to find out other attributes that can be used to reduce the pitfalls in the amplitude interpretation. Some seismic attributes were examined and studies showed that the attenuation attribute is a better attribute for hydrocarbon prediction. Theoretically, the attenuation mechanism of wave propagation is associated with the movement of fluid in the pore; hence the existence of hydrocarbon in the pore will be represented by attenuation attribute directly. In this paper we evaluated the feasibility of the quality factor ratio of P-wave and S-wave (Qp/Qs) as hydrocarbon indicator using well data and also we developed a new attribute based on attenuation for hydrocarbon prediction -- Normalized Energy Reduction Stack (NERS). To achieve these goals, this work was divided into 3 main parts; estimating the Qp/Qs on well log data, testing the new attribute in the synthetic data and applying the new attribute on real data in Malay Basin data. The result show that the Qp/Qs is better than Poisson's ratio and Lamda over Mu as hydrocarbon indicator. The curve, trend analysis and contrast of Qp/Qs is more powerful at distinguishing pore fluid than Poisson ratio and Lamda over Mu. The NERS attribute was successful in distinguishing the hydrocarbon from brine on synthetic data. Applying this attribute on real data on Malay basin, the NERS attribute is qualitatively conformable with the structure and location where the gas is predicted. The quantitative interpretation of this attribute for hydrocarbon prediction needs to be investigated further.

  16. Extragalactic Background Light and Gamma-Ray Attenuation

    OpenAIRE

    Primack, Joel R.; Dominguez, Alberto; Gilmore, Rudy C.; Somerville, Rachel S.

    2011-01-01

    Data from (non-) attenuation of gamma rays from active galactic nuclei (AGN) and gamma ray bursts (GRBs) give upper limits on the extragalactic background light (EBL) from the UV to the mid-IR that are only a little above the lower limits from observed galaxies. These upper limits now rule out some EBL models and purported observations, with improved data likely to provide even stronger constraints. We present EBL calculations both based on multiwavelength observations of thousands of galaxie...

  17. Fluvoxamine Attenuated Endoplasmic Reticulum Stress-Induced Leptin Resistance

    OpenAIRE

    Hosoi, Toru; Miyahara, Tsuyoshi; Kayano, Takaaki; Yokoyama, Shota; Ozawa, Koichiro

    2012-01-01

    Increasing evidence indicates that endoplasmic reticulum stress (ER stress) is involved in the development of metabolic syndrome. However, pharmacological treatments targeting ER stress are not well understood. In the present study, we found that fluvoxamine, a selective serotonin reuptake inhibitor used for depression, can attenuate ER stress-induced “leptin resistance,” i.e., insensitivity to the anti-obesity hormone leptin. Treatment with tunicamycin, an ER stress-inducing reagent, caused ...

  18. Reactogenicity to a Live Attenuated Varicella Vaccine in Canadian Children

    OpenAIRE

    Diaz-Mitoma, Francisco; Halperin, Scott A.; Scheifele, David

    2000-01-01

    OBJECTIVE: To assess the reactogenicity and safety of a thermostable, high titre, varicella vaccine in healthy infants and children.DESIGN: Open study of 505 children monitored for 42 days after vaccination.SETTING: Three urban Canadian centres (Halifax, Ottawa and Vancouver).PARTICIPANTS: 505 healthy children one to 12 years of age were enrolled and 504 completed the study. All were susceptible to varicella by history.INTERVENTIONS: All participants received one dose of live attenuated varic...

  19. Cathepsin B inactivation attenuates hepatic injury and fibrosis during cholestasis

    OpenAIRE

    Canbay, Ali; Guicciardi, Maria Eugenia; Higuchi, Hajime; Feldstein, Ariel; Bronk, Steven F.; Rydzewski, Robert; Tanai, Makiko; Gores, Gregory J.

    2004-01-01

    Although a lysosomal, cathepsin B–dependent (Ctsb-dependent) pathway of apoptosis has been described, the contribution of this pathway to tissue damage remains unclear. Our aim was to ascertain if Ctsb inactivation attenuates liver injury, inflammation, and fibrogenesis after bile duct ligation (BDL). In 3-day BDL mice, hepatocyte apoptosis, mitochondrial cytochrome c release, and serum alanine aminotransferase (ALT) values were reduced in Ctsb–/– versus Ctsb+/+ animals. Likewise, R-3032 (a C...

  20. Clarithromycin attenuates mastectomy-induced acute inflammatory response

    OpenAIRE

    Chow, Louis W. C.; Yuen, Kwok-Yung; Woo, Patrick C. Y.; Wei, William I.

    2000-01-01

    Based on the observation that administration of clarithromycin led to an attenuation of the inflammatory response induced by surgical trauma in a guinea pig model, we investigated the potential beneficial effects of clarithromycin on the local and systemic inflammatory response in patients undergoing mastectomy in an open-label prospective study. During a 16-month period, 54 patients who underwent mastectomy were randomly divided into two groups. In one group, the patients received oral clari...

  1. Poliovirus tropism and attenuation are determined after internal ribosome entry

    OpenAIRE

    Kauder, Steven E.; Racaniello, Vincent R

    2004-01-01

    Poliovirus replication is limited to a few organs, including the brain and spinal cord. This restricted tropism may be a consequence of organ-specific differences in translation initiation by the poliovirus internal ribosome entry site (IRES). A C-to-U mutation at base 472 in the IRES of the Sabin type 3 poliovirus vaccine strain, known to attenuate neurovirulence, may further restrict tropism by eliminating viral replication in the CNS. To determine the relationship between IRES-mediated tra...

  2. Simvastatin attenuates ventilator-induced lung injury in mice

    OpenAIRE

    Müller, Holger C; Hellwig, Katharina; Rosseau, Simone; Tschernig, Thomas; Schmiedl, Andreas; Gutbier, Birgitt; Schmeck, Bernd; Hippenstiel, Stefan; Peters, Harm; Morawietz, Lars; Suttorp, Norbert; Witzenrath, Martin

    2010-01-01

    Introduction Mechanical ventilation (MV) is a life saving intervention in acute respiratory failure without alternative. However, particularly in pre-injured lungs, even protective ventilation strategies may evoke ventilator-induced lung injury (VILI), which is characterized by pulmonary inflammation and vascular leakage. Adjuvant pharmacologic strategies in addition to lung protective ventilation to attenuate VILI are lacking. Simvastatin exhibited anti-inflammatory and endothelial barrier s...

  3. 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. PMID:22204917

  4. Attenuation of S wave in the crust of Ordos massif

    Institute of Scientific and Technical Information of China (English)

    LIU Hong-gui; CHUO Yong-qing; CHEN Shu-qing; JIN Chun-hua

    2005-01-01

    We presented attenuation characteristics of S waves in the crust of Ordos massif. Using 487 pieces of digital oscillograms of 19 seismic events recorded by 32 seismologic stations located on Ordos massif and its surroundings, we have calculated the parameter of three-segment geometric attenuation and give the relation of inelastic attenuation Q value with frequency in the crust of Ordos massif, site responses of 32 stations, and source parameters of 19 events by the genetic algorithm. The results indicate that Q value (at 1 Hz) of S-wave in the crust of Ordos massif is much larger than that in the geologically active tectonic region. The site responses of the 32 stations in the high-frequency section do not show clear amplification effect except one or two stations, while in the low-frequency section, there is difference among the stations. The logarithmic value of seismic moment and the magnitude ML of 19 seismic events has a very good linear relationship.

  5. Dust Attenuation in High Redshift Galaxies -- 'Diamonds in the Sky'

    CERN Document Server

    Scoville, Nick; Capak, Peter; Kakazu, Yuko; Li, Gongjie; Steinhardt, Charles

    2014-01-01

    We use observed optical to near infrared spectral energy distributions (SEDs) of 266 galaxies in the COSMOS survey to derive the wavelength dependence of the dust attenuation at high redshift. All of the galaxies have spectroscopic redshifts in the range z = 2 to 6.5. The presence of the CIV absorption feature, indicating that the rest-frame UV-optical SED is dominated by OB stars, is used to select objects for which the intrinsic, unattenuated spectrum has a well-established shape. Comparison of this intrinsic spectrum with the observed broadband photometric SED then permits derivation of the wavelength dependence of the dust attenuation. The derived dust attenuation curve is similar in overall shape to the Calzetti curve for local starburst galaxies. We also see the 2175 \\AA~bump feature which is present in the Milky Way and LMC extinction curves but not seen in the Calzetti curve. The bump feature is commonly attributed to graphite or PAHs. No significant dependence is seen with redshift between sub-sample...

  6. An adaptive noise attenuation method for edge and amplitude preservation

    Institute of Scientific and Technical Information of China (English)

    Cai Han-Peng; He Zhen-Hua; Li Ya-Lin; He Guang-Ming; Zou Wen; Zhang Dong-Jun; Liu Pu

    2014-01-01

    Noise intensity distributed in seismic data varies with different frequencies or frequency bands; thus, noise attenuation on the full-frequency band affects the dynamic properties of the seismic reflection signal and the subsequent seismic data interpretation, reservoir description, hydrocarbon detection, etc. Hence, we propose an adaptive noise attenuation method for edge and amplitude preservation, wherein the wavelet packet transform is used to decompose the full-band seismic signal into multiband data and then process these data using nonlinear anisotropic dip-oriented edge-preservingfi ltering. In the fi ltering, the calculated diffusion tensor from the structure tensor can be exploited to establish the direction of smoothing. In addition, the fault confidence measure and discontinuity operator can be used to preserve the structural and stratigraphic discontinuities and edges, and the decorrelation criteria can be used to establish the number of iterations. These parameters can minimize the intervention and subjectivity of the interpreter, and simplify the application of the proposed method. We applied the proposed method to synthetic and real 3D marine seismic data. We found that the proposed method could be used to attenuate noise in seismic data while preserving the effective discontinuity information and amplitude characteristics in seismic refl ection waves, providing high-quality data for interpretation and analysis such as high-resolution processing, attribute analysis, and inversion.

  7. Simulating atmospheric free-space optical propagation: rainfall attenuation

    Science.gov (United States)

    Achour, Maha

    2002-04-01

    With recent advances and interest in Free-Space Optics (FSO) for commercial deployments, more attention has been placed on FSO weather effects and the availability of global weather databases. The Meteorological Visual Range (Visibility) is considered one of the main weather parameters necessary to estimate FSO attenuation due to haze, fog and low clouds. Proper understanding of visibility measurements conducted throughout the years is essential. Unfortunately, such information is missing from most of the databases, leaving FSO players no choice but to use the standard visibility equation based on 2% contrast and other assumptions on the source luminance and its background. Another challenge is that visibility is measured using the visual wavelength of 550 nm. Extrapolating the measured attenuations to longer infrared wavelengths is not trivial and involves extensive experimentations. Scattering of electromagnetic waves by spherical droplets of different sizes is considered to simulate FSO scattering effects. This paper serves as an introduction to a series of publications regarding simulation of FSO atmospheric propagation. This first part focuses on attenuation due to rainfall. Additional weather parameters, such as rainfall rate, temperature and relative humidity are considered to effectively build the rain model. Comparison with already published experimental measurement is performed to validate the model. The scattering cross section due to rain is derived from the density of different raindrop sizes and the raindrops fall velocity is derived from the overall rainfall rate. Absorption due the presence of water vapor is computed using the temperature and relative humidity measurements.

  8. Clinical evaluation strategies for a live attenuated tetravalent dengue vaccine.

    Science.gov (United States)

    Precioso, Alexander Roberto; Palacios, Ricardo; Thomé, Beatriz; Mondini, Gabriella; Braga, Patrícia; Kalil, Jorge

    2015-12-10

    Butantan Institute is a public Brazilian biomedical research-manufacturer center affiliated to the São Paulo State Secretary of Health. Currently, Butantan is one of the main public producers of vaccines, antivenoms, and antitoxins in Latin America. The partnership between Butantan and the National Institutes of Health (NIH) of the United Sates has been one of the longest and most successful partnerships in the development and manufacturing of new vaccines. Recently, Butantan Institute has developed and manufactured a lyophilized tetravalent live attenuated dengue vaccine with the four dengue viruses attenuated and licensed from the Laboratory of Infectious Diseases at The National Institutes of Allergy and Infectious Diseases (LID/NIAID/NIH). The objective of this paper is to describe the clinical evaluation strategies of a live attenuated tetravalent dengue vaccine (Butantan-DV) developed and manufactured by Butantan Institute. These clinical strategies will be used to evaluate the Butantan-DV Phase III trial to support the Butantan-DV licensure for protection against any symptomatic dengue caused by any serotype in people aged 2 to 59 years.

  9. 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.

  10. Gender differences in real-world hearing protector attenuation.

    Science.gov (United States)

    Abel, S M; Alberti, P W; Rokas, D

    1988-04-01

    This research investigated the possibility of differences in real-world attenuation attributable to gender. A total of 160 subjects, 80 males and 80 females, under the age of 45 years, and with normal hearing, were tested. Subjects were assigned to four hearing protector categories with the restriction that there were 20 males and 20 females in each group. The devices chosen for study were the E-A-R expandable foam plug, the Willson Sound Silencer premolded vinyl plug with double flange, the Bilsom Soft polyethylene encapsulated glass fiber plug, and the MSA Ear Defender (V-51R) premolded vinyl plug with single flange. Binaural headphone detection thresholds were measured in quiet with the open ear, and subsequently with protectors fitted binaurally for one-third octave noise bands centered at 250, 500, 1000, 3150 and 6300 Hz. The results indicated that attenuation scores achieved by females were less than those observed for males when the device was sold in only one size. Apart from the question of adequate sizing, for two of the insert protectors studied, mean achieved attenuation fell short of the manufacturer's specifications by as much as 18 dB, for particular frequencies tested. The relatively wide variation in scores observed for all four protectors in spite of experimenter-fit could not be accounted for by differences in either hearing threshold across subjects or by size of plug fit, for those devices available in several sizes.

  11. GPR data noise attenuation on the curvelet transform

    Institute of Scientific and Technical Information of China (English)

    Bao Qian-Zong; Li Qing-Chun; Chen Wen-Chao

    2014-01-01

    Signal extraction is critical in GRP data processing and noise attenuation. When the target depth is shallow, its refl ection echo signal will overlap with the background noise, affecting the detection of arrival time and localization of the target. Thus, we propose a noise attenuation method based on the curvelet transform. First, the original signal is transformed into the curvelet domain, and then the curvelet coefficients of the background noise are extracted according to the distribution features that differ from the effective signal. In the curvelet domain, the coarse-scale curvelet atom is isotropic. Hence, a two-dimensional directional filter is designed to estimate the high-energy background noise in the coarse-scale domain, and then, attenuate the background noise and highlight the effective signal. In this process, we also use a subscale threshold value of the curvelet domain tofi lter out random noise. Finally, we compare the proposed method with the average elimination and 2D continuous wavelet transform methods. The results show that the proposed method not only removes the background noise but also eliminates the coherent interference and random noise. The numerical simulation and the real data application suggest and verify the feasibility and effectiveness of the proposed method.

  12. Multicomponent seismic noise attenuation with multivariate order statistic filters

    Science.gov (United States)

    Wang, Chao; Wang, Yun; Wang, Xiaokai; Xun, Chao

    2016-10-01

    The vector relationship between multicomponent seismic data is highly important for multicomponent processing and interpretation, but this vector relationship could be damaged when each component is processed individually. To overcome the drawback of standard component-by-component filtering, multivariate order statistic filters are introduced and extended to attenuate the noise of multicomponent seismic data by treating such dataset as a vector wavefield rather than a set of scalar fields. According to the characteristics of seismic signals, we implement this type of multivariate filtering along local events. First, the optimal local events are recognized according to the similarity between the vector signals which are windowed from neighbouring seismic traces with a sliding time window along each trial trajectory. An efficient strategy is used to reduce the computational cost of similarity measurement for vector signals. Next, one vector sample each from the neighbouring traces are extracted along the optimal local event as the input data for a multivariate filter. Different multivariate filters are optimal for different noise. The multichannel modified trimmed mean (MTM) filter, as one of the multivariate order statistic filters, is applied to synthetic and field multicomponent seismic data to test its performance for attenuating white Gaussian noise. The results indicate that the multichannel MTM filter can attenuate noise while preserving the relative amplitude information of multicomponent seismic data more effectively than a single-channel filter.

  13. Attenuation Tomography of Sierra Negra Volcano of the Galapagos Archipelago

    Science.gov (United States)

    Rodd, R.; Lees, J. M.

    2014-12-01

    Following relocation of events with the double-difference location algorithm (HypoDD), we apply tomographic methods to extract 3D attenuation models illuminating the plumbing system of the Sierra Negra Caldera of the Galapagos Archipelago. The dataset consists of 1737 events recorded from July 2009 to June 2011 on the 17-station SIGNET broadband seismic array. We use t* spectral decay methods for both P- and S- phases with the clustered locations to highlight locations where significant variations in Q suggest the presence of magma melt. While the presence of a magma sill, at least 2 km depth, is indicated by InSAR and GPS studies, the delineated magma body has not been explored in detail. The lower bound of the proposed magma accumulation is still under question and thus forms the primary target of this research. Melt replenishment and degassing of the magma sill is believed to cause inflation and/or deflation of the caldera floor. Imaging the extent of the magma sill will provide insight into the feeder system and deformation process of the Sierra Negra caldera. Detailed relocation, Qp and Qs inversion, as well as estimates of the scattering attenuation using coda-normalization technique will be presented. The close relationship between seismic attenuation and the thermal state of the magmatic system suggests we can distinguish melt and/or fluid regions within the Sierra Negra plumbing system.

  14. 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.

  15. Plasmodium yoelii: induction of attenuated mutants by irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Waki, S.; Yonome, I.; Suzuki, M.

    1986-12-01

    When erythrocytic forms of Plasmodium yoelii nigeriensis, which is invariably fatal in mice, were exposed to X rays, the dose to reduce surviving parasites to one millionth was 100 gray (10 Krad). A suspension of 5 X 10(6) per ml of parasitized erythrocyte was irradiated at 100 gray, and 0.2 ml aliquots were inoculated into 22 mice. Eleven mice showed patent parasitemia, and in these the growth curves were less steep than that found in nonirradiated parasites. The infections of 8 mice of the 11 were self-resolving, and the attenuated feature of the parasites maintained following a limited number of blood passages. The parasites were slowly growing even in nude mice and cause self-resolving infections in intact mice. BALB/c mice immunized with the attenuated parasites were protected against subsequent challenge infections with the original virulent erythrocytic and sporogonic forms. These findings indicate that attenuated mutants of malaria parasites can be readily induced by this method.

  16. Heavy weight concrete with special mixes for neutron attenuation

    International Nuclear Information System (INIS)

    This work is concerned with the study of the attenuation properties of special mixes of magnetite concrete for fast and thermal neutrons. Investigations were carried out using a collimated beam of neutrons emitted from Pu-α-Be and Californium-252 neutron sources. The fast spectra of neutrons were measured by a scintillation spectrometer with stilbene crystal. Discrimination against undesired pulses of neutrons or gamma -rays was achieved by a zero crossover method. The thermal neutron fluxes were measured by a BF3 detector. The obtained data are displayed in the form of spectra for fast neutrons and attenuation relations for thermal neutrons.The thermal neutron fluxes were measured using bare beam and beams filtered by 113 Cd and B4 C filters to discuss the origin of thermal neutrons interacting with the concrete samples. The obtained results were also used to derive the attenuation coefficients for total thermal neutrons and for newly produced thermal neutrons resulting from neutron beams filtered by 113 Cd and B4 C in the different magnetite concrete shields of different thicknesses.

  17. Comparison of Reg. Guide 1.99 fluence attenuation methods

    Energy Technology Data Exchange (ETDEWEB)

    Jones, E.N. [TransWare Enterprises Inc., 1565 Mediterranean Dr., Sycamore, IL 60178 (United States)

    2011-07-01

    U.S. Regulatory Guide 1.99 Revision 2 (U.S. Nuclear Regulatory Commission, 1988, 'Radiation Embrittlement of Reactor Vessel Materials,' Regulatory Guide 1.99, Revision 2, Washington, D.C.) provides for the use of two substantially different methods for determining through-wall fluence in nuclear reactor pressure vessels. One method is a generic attenuation curve based on a simplistic exponential decay equation. Partly due to the simplicity of its application, the generic attenuation method is predominantly used for licensing calculations. However, it has a limitation in that at increasing distances away from the core belt-line, it becomes increasingly less accurate because it cannot account for neutron streaming effects in the cavity region surrounding the pressure vessel. The other attenuation method is based on a displacement per atom (dpa) calculation specific to the reactor vessel structure. The dpa method provides a more accurate representation of fluence attenuation through the reactor pressure vessel (RPV) wall at all elevations of the pressure vessel because it does account for neutron streaming in the cavity region. A requirement for using the dpa method, however, is an accurate flux solution through the RPV wall. This requirement has limited the use of traditional transport methods, such as discrete ordinates, that are limited by their treatment of cavity regions (i.e., air) outside the pressure vessel wall. TransWare Enterprises, under the sponsorship of EPRI and BWRVIR has developed an advanced three-dimensional transport methodology capable of producing fully converged flux solutions throughout the entire reactor system, including in the cavity region and primary shield structures. This methodology provides an accurate and reliable determination of through-wall fluence in boiling water reactor (BWR) and pressurized water reactor (PWR) pressure vessels, thus allowing the dpa method to be implemented with high reliability. Using this advanced 3

  18. Forward- vs. Inverse Problems in Modeling Seismic Attenuation

    Science.gov (United States)

    Morozov, I. B.

    2015-12-01

    Seismic attenuation is an important property of wave propagation used in numerous applications. However, the attenuation is also a complex phenomenon, and it is important to differentiate between its two typical uses: 1) in forward problems, to model the amplitudes and spectral contents of waves required for hazard assessment and geotechnical engineering, and 2) in inverse problems, to determine the physical properties of the subsurface. In the forward-problem sense, the attenuation is successfully characterized in terms of empirical parameters of geometric spreading, radiation patterns, scattering amplitudes, t-star, alpha, kappa, or Q. Arguably, the predicted energy losses can be correct even if the underlying attenuation model is phenomenological and not sufficiently based on physics. An example of such phenomenological model is the viscoelasticity based on the correspondence principle and the Q-factor assigned to the material. By contrast, when used to invert for in situ material properties, models addressing the specific physics are required. In many studies (including in this session), a Q-factor is interpreted as a property of a point within the subsurface; however this property is only phenomenological and may be physically insufficient or inconsistent. For example, the bulk or shear Q at the same point can be different when evaluated from different wave modes. The cases of frequency-dependent Q are particularly prone of ambiguities such as trade-off with the assumed background geometric spreading. To rigorously characterize the in situ material properties responsible for seismic-wave attenuation, it is insufficient to only focus on the seismic energy loss. Mechanical models of the material need to be considered. Such models can be constructed by using Lagrangian mechanics. These models should likely contain no Q but will be based on parameters of microstructure such as heterogeneity, fractures, or fluids. I illustrate several such models based on viscosity

  19. Polymerase Mechanism-Based Method of Viral Attenuation

    Science.gov (United States)

    Lee, Cheri A.; August, Avery; Arnold, Jamie J.; Cameron, Craig E.

    2016-01-01

    Vaccines remain the most effective way of preventing infection and spread of infectious diseases. These prophylactics have been used for centuries but still to this day only three main design strategies exist: (1) live attenuated virus (LAV) vaccines, (2) killed or inactivated virus vaccines, (3) and subunit vaccines of the three, the most efficacious vaccines remain LAVs. LAVs replicate in relevant tissues, elicit strong cellular and humoral responses, and often confer lifelong immunity. While this vaccine strategy has produced the majority of successful vaccines in use today, there are also important safety concerns to consider with this approach. In the past, the development of LAVs has been empirical. Blind passage of viruses in various cell types results in the accumulation of multiple attenuating mutations leaving the molecular mechanisms of attenuation unknown. Also, due to the high error rate of RNA viruses and selective pressures of the host environment, these LAVs, derived from such viruses, can potentially revert back to wild-type virulence. This not only puts the vaccinee at risk, but if shed can put those that are unvaccinated at risk as well. While these vaccines have been successful there still remains a need for a rational design strategy by which to create additional LAVs. One approach for rational vaccine design involves increasing the fidelity of the viral RdRp. Increased fidelity decreases the viral mutational frequency thereby reducing the genetic variation the virus needs in order to evade the host imposed bottlenecks to infection. While polymerase mutants exist which decrease viral mutation frequency the mutations are not in conserved regions of the polymerase, which doesn’t lend itself toward using a common mutant approach toward developing a universal vaccine strategy for all RNA viruses. We have identified a conserved lysine residue in the active site of the PV RdRp that acts as a general acid during nucleotide incorporation. Mutation

  20. A two-component rain model for the prediction of attenuation statistics

    Science.gov (United States)

    Crane, R. K.

    1982-01-01

    A two-component rain model has been developed for calculating attenuation statistics. In contrast to most other attenuation prediction models, the two-component model calculates the occurrence probability for volume cells or debris attenuation events. The model performed significantly better than the International Radio Consultative Committee model when used for predictions on earth-satellite paths. It is expected that the model will have applications in modeling the joint statistics required for space diversity system design, the statistics of interference due to rain scatter at attenuating frequencies, and the duration statistics for attenuation events.

  1. Crustal structure of the Alps as seen by attenuation tomography

    Science.gov (United States)

    Mayor, Jessie; Calvet, Marie; Margerin, Ludovic; Vanderhaeghe, Olivier; Traversa, Paola

    2016-04-01

    We develop a simple tomographic approach exploiting the decay rate of coda waves to map the absorption properties of the crust in a region delimited approximately by the Rhine Graben to the North, the Apennines to the South, the Massif Central to the West and the Dinarides to the East. Our dataset comprises 40 000 coda records of about 2000 weak to moderate crustal earthquakes, with magnitude ranging from 2.8 to 6 and recorded by broad-band, accelerometric and short-period stations. After proper choice of a coda window minimizing the effects of variable epicentral distances, we measure the coda quality factor Qc in five non-overlapping frequency windows covering the 1-32 Hz band for all available source station pairs. These measurements are subsequently converted into maps of absorption quality factor (Qi) using a linearized, approximate relation between Qc and Qi. In practice the following procedure is applied in each frequency band: (1) we divide the target region into 40 × 40 km cells; (2) for each source-station pair, we assign the measured Qc value to each pixel intercepted by the direct ray path; (3) the results are averaged over all paths and subsequently smoothed with a 3 × 3 pixels moving window. Our approach is consistent with the high sensitivity of Qc to the value of Qi between source and station. Our tomographic approach reveals strong lateral variations of absorption with length scales ranging from 100 km to 1000 km. At low frequency (˜ 1 Hz), the correlation with the surface geology is clear, Cenozoic and Mesozoic sedimentary basins (resp. crystalline massifs) being recognized as high (resp. low)-absorption regions. Furthermore the Qi map delineates finer geological features such as the Ivrea Body, the Rhône Valley, or felsic intrusions in the central Alps. At high-frequency (>16 Hz), only the thickest Cenozoic sedimentary deposits show up as high-attenuation regions and a north/south dichotomy is apparent in the absorption structure. The limit

  2. Aspects of flow attenuation performance of retention ponds

    Science.gov (United States)

    Wallis, S. G.; Morgan, C. T.; Heal, K.

    2003-04-01

    The work reported here is part of a wider modelling study into the performance of sustainable urban drainage systems (SUDS) in Scotland. Developments that increase the urbanisation of catchments are now required by the Scottish Environment Protection Agency to include SUDS to protect receiving watercourses from flooding and water quality deterioration. Here we report specifically on some initial simulations of storm water retention ponds. These are normally wet storage facilities that provide both flow attenuation and water quality treatment (from settlement of suspended solids and biological treatment of some pollutants). Here we focus on the flow attenuation characteristics. A sensitivity analysis was performed on a model of a cylindrical pond with outflow through a V-notch weir. The aim of the simulations was to help us to learn about the flow attenuation characteristics of retention ponds, so that later work could be properly focused on the key issues. In addition the flow simulation model underpins later models of water quality and sedimentation, so it was important to ensure that its simulations were realistic. The inflows were constructed using an isosceles triangular inflow hydrograph with a peak flow of 50 l/s, a storm duration of 3.2 hours and a total inflow volume of 288 l. Values of four pond parameters were varied to test model sensitivity: radius, weir angle, weir crest elevation and initial water level. Sensitivity was investigated by observing the changes in several flow attenuation performance indicators. These were total outflow volume, peak outflow and the following three time delays: peak time delay (lag between peaks of outflow and inflow hydrographs), centroid time delay (lag between centroids of outflow and inflow hydrographs) and initial time delay (lag between the initial rise of the outflow and inflow hydrographs). Simulations were carried out using a simple Euler discretisation of the storage routing equation. A time step of 1.5 minutes

  3. Scatter and attenuation correction changes interpretation of gated myocardial perfusion imaging

    DEFF Research Database (Denmark)

    Johansen, Allan; Grupe, Peter; Veje, Annegrete;

    2004-01-01

    Attenuation correction may improve the diagnostic accuracy of myocardial perfusion imaging (MPI). However, few studies have dealt with the clinical consequences for reporting. We compared routine reports based on scatter-corrected MPI (MPI-routine) with consensus readings of scatter-corrected (MPI......-scatter) and scatter plus attenuation-corrected studies (MPI-attenuation) to investigate the impact of attenuation correction on reporting. One hundred consecutive stable angina patients (including 55 men) were investigated in a 99mTc-sestamibi 2-day gated protocol with scatter and attenuation correction. With...... MPI-routine, 53 patients had normal perfusion and 47 abnormal perfusion, compared to 62 and 38 with MPI-attenuation, and 54 and 46, respectively, with MPI-scatter. Agreement between MPI-routine and MPI-attenuation with respect to overall diagnosis (normal/abnormal perfusion) was 89% (kappa=0...

  4. A study on photon attenuation coefficients of different wood materials with different densities

    Science.gov (United States)

    Saritha, B.; Nageswara Rao, A. S.

    2015-12-01

    A study on the variation of linear attenuation coefficients with the densities of the wood samples is under taken. The soft wood and hard wood samples were collected from the forest area of Pakal in Warangal district. The linear and mass attenuation coefficients are measured using gamma ray spectrometry based on NaI (Tl) scintillation detector with energies of 662 KeV and 59.5 KeV respectively. The mass attenuation coefficient values measured from experiment and are compared with theoretical methods using XCOM program. The plots of density versus linear attenuation coefficient for different wood materials correspond to higher order polynomial are presented. It is observed that variation of linear attenuation coefficient depends on densities of materials. The Chloroxylon swietenia with more density has more linear attenuation coefficient at 59.5 KeV and 662 KeV. The variation in attenuation coefficient attributed to chemical composition of wood used in the experiment.

  5. Development of a human live attenuated West Nile infectious DNA vaccine: Suitability of attenuating mutations found in SA14-14-2 for WN vaccine design.

    Science.gov (United States)

    Yamshchikov, Vladimir; Manuvakhova, Marina; Rodriguez, Efrain

    2016-01-01

    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 E138K and K279M 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.

  6. Detailed analysis of the promoter activity of an attenuated lentivirus.

    Science.gov (United States)

    Blatti-Cardinaux, Laure; Sanjosé, Leticia; Zahno, Marie-Luise; Zanoni, Reto; Reina, Ramses; Bertoni, Giuseppe

    2016-07-01

    In spite of an eradication campaign that eliminated clinical cases of caprine arthritis encephalitis virus-induced arthritis in the Swiss goat population, seroconversions are still observed. In the affected flocks, viruses belonging mainly to the small ruminant lentivirus A4 subtype are regularly isolated. These viruses are considered attenuated, except in the mammary gland, where high viral loads and histopathological lesions have been observed. We previously characterized and sequenced such field isolates, detecting several potentially attenuating mutations in their LTR. Here we present a detailed analysis of the promoter activity of these genetic elements, which was comparable to those of virulent isolates. An AP-1 binding site was shown to be crucial for promoter activity in reporter gene assays and also in the context of a replicating molecular clone. Other sites, such as AML(vis) and a conserved E-box, appeared to be less crucial. Analysis of a unique AP-4 site showed a clear discrepancy between results obtained with reporter gene assays and those with mutated viruses. Within the limits of this in vitro study, we did not find evidence pointing to the LTR as the genetic correlate of attenuation for these viruses. Finally, the limited replication of SRLV A4 in mammary cell culture could not explain the suggested mammary tropism. In contrast, and in view of the abundance of macrophages in the mammary gland, it is the striking replication capacity of SRLV A4 in these cells, unaffected by all LTR mutations tested, which may explain the apparent mammary tropism of these viruses. PMID:27114068

  7. 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.

  8. Attenuation of shock waves in copper and stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Harvey, W.B.

    1986-06-01

    By using shock pins, data were gathered on the trajectories of shock waves in stainless steel (SS-304L) and oxygen-free-high-conductivity copper (OFHC-Cu). Shock pressures were generated in these materials by impacting the appropriate target with thin (approx.1.5 mm) flying plates. The flying plates in these experiments were accelerated to high velocities (approx.4 km/s) by high explosives. Six experiments were conducted, three using SS-304L as the target material and three experiments using OFHC-Cu as the target material. Peak shock pressures generated in the steel experiments were approximately 109, 130, and 147 GPa and in the copper experiments, the peak shock pressures were approximately 111, 132, and 143 GPa. In each experiment, an attenuation of the shock wave by a following release wave was clearly observed. An extensive effort using two characteristic codes (described in this work) to theoretically calculate the attenuation of the shock waves was made. The efficacy of several different constitutive equations to successfully model the experiments was studied by comparing the calculated shock trajectories to the experimental data. Based on such comparisons, the conclusion can be drawn that OFHC-Cu enters a melt phase at about 130 GPa on the principal Hugoniot. There was no sign of phase changes in the stainless-steel experiments. In order to match the observed attenuation of the shock waves in the SS-304L experiments, it was necessary to include strength effects in the calculations. It was found that the values for the parameters in the strength equations were dependent on the equation of state used in the modeling of the experiments. 66 refs., 194 figs., 77 tabs.

  9. Cilostazol attenuates ovariectomy-induced bone loss by inhibiting osteoclastogenesis.

    Directory of Open Access Journals (Sweden)

    Ke Ke

    Full Text Available Cilostazol has been reported to alleviate the metabolic syndrome induced by increased intracellular adenosine 3',5'-cyclic monophosphate (cAMP levels, which is also associated with osteoclast (OC differentiation. We hypothesized that bone loss might be attenuated via an action on OC by cilostazol.To test this idea, we investigated the effect of cilostazol on ovariectomy (OVX-induced bone loss in mice and on OC differentiation in vitro, using μCT and tartrate-resistant acid phosphatase staining, respectively. Cilostazol prevented from OVX-induced bone loss and decreased oxidative stress in vivo. It also decreased the number and activity of OC in vitro. The effect of cilostazol on reactive oxygen species (ROS occurred via protein kinase A (PKA and cAMP-regulated guanine nucleotide exchange factor 1, two major effectors of cAMP. Knockdown of NADPH oxidase using siRNA of p47phox attenuated the inhibitory effect of cilostazol on OC formation, suggesting that decreased OC formation by cilostazol was partly due to impaired ROS generation. Cilostazol enhanced phosphorylation of nuclear factor of activated T cells, cytoplasmic 1 (NFAT2 at PKA phosphorylation sites, preventing its nuclear translocation to result in reduced receptor activator of nuclear factor-κB ligand-induced NFAT2 expression and decreased binding of nuclear factor-κB-DNA, finally leading to reduced levels of two transcription factors required for OC differentiation.Our data highlight the therapeutic potential of cilostazol for attenuating bone loss and oxidative stress caused by loss of ovarian function.

  10. Optical coherence tomography for blood glucose monitoring through signal attenuation

    Science.gov (United States)

    De Pretto, Lucas R.; Yoshimura, Tania M.; Ribeiro, Martha S.; de Freitas, Anderson Z.

    2016-03-01

    Development of non-invasive techniques for glucose monitoring is crucial to improve glucose control and treatment adherence in patients with diabetes. Hereafter, Optical Coherence Tomography (OCT) may offer a good alternative for portable glucometers, since it uses light to probe samples. Changes in the object of interest can alter the intensity of light returning from the sample and, through it, one can estimate the sample's attenuation coefficient (μt) of light. In this work, we aimed to explore the behavior of μt of mouse's blood under increasing glucose concentrations. Different samples were prepared in four glucose concentrations using a mixture of heparinized blood, phosphate buffer saline and glucose. Blood glucose concentrations were measured with a blood glucometer, for reference. We have also prepared other samples diluting the blood in isotonic saline solution to check the effect of a higher multiple-scattering component on the ability of the technique to differentiate glucose levels based on μt. The OCT system used was a commercial Spectral Radar OCT with 930 nm central wavelength and spectral bandwidth (FWHM) of 100 nm. The system proved to be sensitive for all blood glucose concentrations tested, with good correlations with the obtained attenuation coefficients. A linear tendency was observed, with an increase in attenuation with higher values of glucose. Statistical difference was observed between all groups (p<0.001). This work opens the possibility towards a non-invasive diagnostic modality using OCT for glycemic control, which eliminates the use of analytes and/or test strips, as in the case with commercially available glucometers.

  11. Natural attenuation of hydrocarbon polluted soils in Mexico

    International Nuclear Information System (INIS)

    Crude oil and hydrocarbon by-proudcts are the most common pollutants in Mexico. In the last years, the two terms, contamination and remediation have being re-defined; also, based on both the scientific advancement and the human risk, the sustentability of remediation technologies and the definition of cleaning levels has been taking place. In this context, the Natural Attenuation of soils is a viable and low cost remediation choice, defined as the degradation of organic compounds without artificial stimulation, through microbial activity including physical processes, such as volatilization, dilution, sorption, and hydraulic dispersion. (Author)

  12. Research progress in live attenuated Brucella vaccine development.

    Science.gov (United States)

    Wang, Zhen; Wu, Qingmin

    2013-01-01

    Brucella spp. are facultative intracellular bacteria that cause brucellosis, which is a globally occurring zoonotic disease that is characterized by abortion in domestic animals and undulant fever, arthritis, endocarditis, and meningitis in humans. There are currently no licensed vaccines against brucellosis for human use, and only a few licensed live Brucella vaccines are available for use in animals. However, the available animal vaccines may cause abortion and are associated with lower protection rates in animals and higher virulence in humans. Much research has been performed recently to develop novel Brucella vaccines for the prevention and control of animal brucellosis. This article discusses the approaches and strategies for novel live attenuated vaccine development.

  13. Live attenuated varicella vaccine in children with leukemia in remission.

    Science.gov (United States)

    Gershon, A A; Steinberg, S; Galasso, G; Borkowsky, W; Larussa, P; Ferrara, A; Gelb, L

    1984-09-01

    One-hundred-ninety-one children with acute leukemia in remission for at least one year were immunized with 1 or more doses of live attenuated varicella vaccine. All were susceptible to varicella prior to vaccination. The only significant side effect was mild to moderate rash, seen especially in children with maintenance chemotherapy temporarily suspended for one week before and one week after vaccination. Children with rash were at some risk (10%) to transmit vaccine virus to varicella susceptibles with whom they had close contact.

  14. Study on laser and infrared attenuation performance of carbon nanotubes

    Science.gov (United States)

    Liu, Xiang-cui; Liu, Qing-hai; Dai, Meng-yan; Cheng, Xiang; Fang, Guo-feng; Zhang, Tong; Liu, Haifeng

    2014-11-01

    In recent years, the weapon systems of laser and infrared (IR) imaging guidance have been widely used in modern warfare because of their high precision and strong anti-interference. However, military smoke, a rapid and effective passive jamming method, can effectively counteract the attack of precision-guided weapons by their scattering and absorbing effects. The traditional smoke has good visible light (0.4-0.76μm) obscurant performance, but hardly any effects to other electromagnetic wave bands while the weapon systems of laser and IR imaging guidance usually work in broad band, including the near-infrared (1-3μm), middle-infrared (3-5μm), far-infrared (8-14μm), and so on. Accordingly, exploiting new effective obscurant materials has attracted tremendous interest worldwide nowadays. As is known, the nano-structured materials have lots of unique properties comparing with the traditional materials suggesting that they might be the perfect alternatives to solve the problems above. Carbon nanotubes (CNTs) are well-ordered, all-carbon hollow graphitic nano-structured materials with a high aspect ratio, lengths from several hundred nanometers to several millimeters. CNTs possess many unique intrinsic physical-chemical properties and are investigated in many areas reported by the previous studies. However, no application research about CNTs in smoke technology field is reported yet. In this paper, the attenuation performances of CNTs smoke to laser and IR were assessed in 20m3 smoke chamber. The testing wavebands employed in experiments are 1.06μm and 10.6μm laser, 3-5μm and 8-14μm IR radiation. The main parameters were obtained included the attenuation rate, transmission rate, mass extinction coefficient, etc. The experimental results suggest that CNTs smoke exhibits excellent attenuation ability to the broadband IR radiation. Their mass extinction coefficients are all above 1m2·g-1. Nevertheless, the mass extinction coefficients vary with the sampling time

  15. Pharmacologically induced hypothermia attenuates traumatic brain injury in neonatal rats.

    Science.gov (United States)

    Gu, Xiaohuan; Wei, Zheng Zachory; Espinera, Alyssa; Lee, Jin Hwan; Ji, Xiaoya; Wei, Ling; Dix, Thomas A; Yu, Shan Ping

    2015-05-01

    Neonatal brain trauma is linked to higher risks of mortality and neurological disability. The use of mild to moderate hypothermia has shown promising potential against brain injuries induced by stroke and traumatic brain injury (TBI) in various experimental models and in clinical trials. Conventional methods of physical cooling, however, are difficult to use in acute treatments and in induction of regulated hypothermia. In addition, general anesthesia is usually required to mitigate the negative effects of shivering during physical cooling. Our recent investigations demonstrate the potential therapeutic benefits of pharmacologically induced hypothermia (PIH) using the neurotensin receptor (NTR) agonist HPI201 (formerly known as ABS201) in stroke and TBI models of adult rodents. The present investigation explored the brain protective effects of HPI201 in a P14 rat pediatric model of TBI induced by controlled cortical impact. When administered via intraperitoneal (i.p.) injection, HPI201 induced dose-dependent reduction of body and brain temperature. A 6-h hypothermic treatment, providing an overall 2-3°C reduction of brain and body temperature, showed significant effect of attenuating the contusion volume versus TBI controls. Attenuation occurs whether hypothermia is initiated 15min or 2h after TBI. No shivering response was seen in HPI201-treated animals. HPI201 treatment also reduced TUNEL-positive and TUNEL/NeuN-colabeled cells in the contusion area and peri-injury regions. TBI-induced blood-brain barrier damage was attenuated by HPI201 treatment, evaluated using the Evans Blue assay. HPI201 significantly decreased MMP-9 levels and caspase-3 activation, both of which are pro-apototic, while it increased anti-apoptotic Bcl-2 gene expression in the peri-contusion region. In addition, HPI201 prevented the up-regulation of pro-inflammatory tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and IL-6. In sensorimotor activity assessments, rats in the HPI201

  16. Disturbance Attenuation State-Feedback Control for Uncertain Interconnected Systems

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    This paper studies the problem of robust H∞ control design for a class of uncertain interconnected systems viastate feedback. This class of systems are described by a state space model, which contains unknown nonlinear interactionand time-varying norm-bounded parametric uncertainties in state equation. Using the Riccati-equation-based approach wedesign state feedback control laws, which guarantee the decentralized stability with disturbance attenuation for the inter-connected uncertain systems. A simple example of an interconnected uncertain linear system is presented to illustrate theresults.

  17. Multi-resolution inversion algorithm for the attenuated radon transform

    KAUST Repository

    Barbano, Paolo Emilio

    2011-09-01

    We present a FAST implementation of the Inverse Attenuated Radon Transform which incorporates accurate collimator response, as well as artifact rejection due to statistical noise and data corruption. This new reconstruction procedure is performed by combining a memory-efficient implementation of the analytical inversion formula (AIF [1], [2]) with a wavelet-based version of a recently discovered regularization technique [3]. The paper introduces all the main aspects of the new AIF, as well numerical experiments on real and simulated data. Those display a substantial improvement in reconstruction quality when compared to linear or iterative algorithms. © 2011 IEEE.

  18. Attenuating wind turbine loads through model based individual pitch control

    DEFF Research Database (Denmark)

    Thomsen, Sven Creutz; Niemann, Hans Henrik; Poulsen, Niels Kjølstad

    2009-01-01

    In this paper we consider wind turbine load attenuation through model based control. Asymmetric loads caused by the wind field can be reduced by pitching the blades individually. To this end we investigate the use of stochastic models of the wind which can be included in a model based individual...... pitch controller design. In this way the variability of the wind can be estimated and compensated for by the controller. The wind turbine model is in general time-variant due to its rotational nature. For this reason the modeling and control is carried out in so-called multiblade coordinates...

  19. Attenuation, dispersion and nonlinearity effects in graphene-based waveguides.

    Science.gov (United States)

    Lima, Almir Wirth; Mota, João Cesar Moura; Sombra, Antonio Sergio Bezerra

    2015-01-01

    We simulated and analyzed in detail the behavior of ultrashort optical pulses, which are typically used in telecommunications, propagating through graphene-based nanoribbon waveguides. In this work, we showed the changes that occur in the Gaussian and hyperbolic secant input pulses due to the attenuation, high-order dispersive effects and nonlinear effects. We concluded that it is possible to control the shape of the output pulses with the value of the input signal power and the chemical potential of the graphene nanoribbon. We believe that the obtained results will be highly relevant since they can be applied to other nanophotonic devices, for example, filters, modulators, antennas, switches and other devices.

  20. Regional Lg attenuation for the continental United States

    Science.gov (United States)

    Benz, H.M.; Frankel, A.; Boore, D.M.

    1997-01-01

    Measurements of the Fourier amplitude spectra of Lg phases recorded at high frequency (0.5 to 14.0 Hz) by broadband seismic stations are used to determine regional attenuation relationships for southern California, the Basin and Range Province, the central United States, and the northeastern United States and southeastern Canada. Fourier spectral amplitudes were measured every quarter octave from Lg phases windowed between 3.0 and 3.7 km sec-1 and recorded in the distance range of 150 to 1000 km. Attenuation at each frequency is determined by assuming a geometrical spreading exponent of 0.5 and inverting for Q and source and receiver terms. Both southern California and the Basin and Range Province are well described by low Lg Q and frequency-dependent attenuation. Lg spectral amplitudes in southern California are fit at low frequencies (0.625 to 0.875 Hz) by a constant Lg Q of 224 and by a frequency-dependent Lg Q function Q = 187-7+7 f0.55(??0.03) in the frequency band 1.0 to 7.0 Hz. The Basin and Range Province is characterized by a constant Lg Q of 192 for frequencies of 0.5 to 0.875 Hz and by the frequency-dependent Lg Q function Q = 235-11+11 f0.56(??0.04) in the frequency band 1.0 to 5.0 Hz. A change in frequency dependence above 5.0 Hz is possible due to contamination of the Lg window by Pn and Sn phases. Lg spectral amplitudes in the central United States are fit by a mean frequency-independent Lg Q of 1291 for frequencies of 1.5 to 7.0 Hz, while a frequency-dependent Lg Q of Q = 1052-83+91(f/1.5)0.22(??0.06) fits the Lg spectral amplitudes for the northeastern United States and southeastern Canada over the passband 1.5 to 14.0 Hz. Attenuation measurements for these areas were restricted to frequencies >1.5 Hz due to larger microseismic noise levels at the lower frequencies.