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Sample records for pv citri pathogenesis

  1. Complete Genome Sequences of Six Copper-Resistant Xanthomonas citri pv.?citri Strains Causing Asiatic Citrus Canker, Obtained Using Long-Read Technology

    OpenAIRE

    Richard, Damien; Boyer, Claudine; Vernière, Christian; Canteros, B.I.; Lefeuvre, Pierre; Pruvost, Olivier

    2017-01-01

    The gammaproteobacterium Xanthomonas citri pv. citri causes Asiatic citrus canker. Pathotype A strains have a broad host range, which includes most commercial citrus species, and they cause important economic losses worldwide. Control often relies on frequent copper sprays. We present here the complete genomes of six X. citri pv. citri copper-resistant strains. (Résumé d'auteur)

  2. Complete Genome Sequences of Six Copper-Resistant Xanthomonas citri pv. citri Strains Causing Asiatic Citrus Canker, Obtained Using Long-Read Technology

    Science.gov (United States)

    Richard, Damien; Boyer, Claudine; Vernière, Christian; Canteros, Blanca I.; Lefeuvre, Pierre

    2017-01-01

    ABSTRACT The gammaproteobacterium Xanthomonas citri pv. citri causes Asiatic citrus canker. Pathotype A strains have a broad host range, which includes most commercial citrus species, and they cause important economic losses worldwide. Control often relies on frequent copper sprays. We present here the complete genomes of six X. citri pv. citri copper-resistant strains. PMID:28336584

  3. Insights into xanthomonas axonopodis pv. Citri biofilm through proteomics

    KAUST Repository

    Zimaro, Tamara

    2013-08-07

    Background: Xanthomonas axonopodis pv. Citri (X. a. pv. Citri) causes citrus canker that can result in defoliation and premature fruit drop with significant production losses worldwide. Biofilm formation is an important process in bacterial pathogens and several lines of evidence suggest that in X. a. pv. Citri this process is a requirement to achieve maximal virulence since it has a major role in host interactions. In this study, proteomics was used to gain further insights into the functions of biofilms. Results: In order to identify differentially expressed proteins, a comparative proteomic study using 2D difference gel electrophoresis was carried out on X. a. pv. Citri mature biofilm and planktonic cells. The biofilm proteome showed major variations in the composition of outer membrane proteins and receptor or transport proteins. Among them, several porins and TonB-dependent receptor were differentially regulated in the biofilm compared to the planktonic cells, indicating that these proteins may serve in maintaining specific membrane-associated functions including signaling and cellular homeostasis. In biofilms, UDP-glucose dehydrogenase with a major role in exopolysaccharide production and the non-fimbrial adhesin YapH involved in adherence were over-expressed, while a polynucleotide phosphorylase that was demonstrated to negatively control biofilm formation in E. coli was down-regulated. In addition, several proteins involved in protein synthesis, folding and stabilization were up-regulated in biofilms. Interestingly, some proteins related to energy production, such as ATP-synthase were down-regulated in biofilms. Moreover, a number of enzymes of the tricarboxylic acid cycle were differentially expressed. In addition, X. a. pv. Citri biofilms also showed down-regulation of several antioxidant enzymes. The respective gene expression patterns of several identified proteins in both X. a. pv. Citri mature biofilm and planktonic cells were evaluated by

  4. Scientific Opinion on the risk to plant health of Xanthomonas citri pv. citri and Xanthomonas citri pv. aurantifolii for the EU territory

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    EFSA Panel on Plant Health (PLH

    2014-02-01

    Full Text Available The Panel conducted a pest risk assessment for Xanthomonas campestris (all strains pathogenic to Citrus for the EU territory and an assessment of the effectiveness of present EU requirements against Xanthomonas strains pathogenic to citrus. The risk assessment was conducted under the scenario of absence of the current specific EU plant health legislation and the assumption that citrus-exporting countries apply measures to reduce yield and quality losses. Risk reduction options were systematically identified and evaluated. The strains of X. campestris pathogenic to citrus have been reclassified as four distinct infraspecific taxa within two species: X. citri and X. alfalfae. Only two pathovars (X. citri pv. citri and X. citri pv. aurantifolii are responsible for the citrus bacterial canker thatpresents a major risk for the citrus industry in the EU. Seven entry pathways have been identified and evaluated. The likelihood of entry was rated unlikely for fruit, very likely for fruit plants for planting, moderately likely for ornamental plants for planting and unlikely for leaves and twigs. The uncertainty of probability of entry was rated as high. The probability of establishment was rated as moderately likely to likely with a medium uncertainty because host plants are widely present in EU areas where environmental conditions are suitable. Once established, spread would be likely with a low uncertainty. The impact of the disease, even if control measures are applied, was rated as moderate to major with a medium uncertainty. The disease would cause yield losses in areas where citrus is the main crop, increase the need for control measures and create environmental problems.The combined EU regulations have been shown to be effective in preventing the introduction of X. citri pv. citri or X. citri pv. aurantifolii in the EU, as no outbreaks of citrus canker in the EU territory have been reported.

  5. Amplified fragment length polymorphism and multilocus sequence analysis-based genotypic relatedness among pathogenic variants of Xanthomonas citri pv. citri and Xanthomonas campestris pv. bilvae.

    Science.gov (United States)

    Bui Thi Ngoc, Lan; Vernière, Christian; Jouen, Emmanuel; Ah-You, Nathalie; Lefeuvre, Pierre; Chiroleu, Frédéric; Gagnevin, Lionel; Pruvost, Olivier

    2010-03-01

    Three pathogenic variants (i.e. pathotypes) have been described within Xanthomonas citri pv. citri, the causal agent of Asiatic citrus canker. Pathotype A strains naturally infect a wide range of Citrus species and members of some related genera. In contrast, pathotypes A* and A(w) have narrow host ranges within the genus Citrus and have been isolated from Mexican lime (Citrus aurantifolia L.) and from Mexican lime and alemow (Citrus macrophylla L.), respectively. We used amplified fragment length polymorphism (AFLP) and multilocus sequence analysis (MLSA) based on four partial housekeeping gene sequences (atpD, dnaK, efp and gyrB ) for the genotypic classification of Xanthomonas citri pv. citri and the poorly characterized citrus pathogen Xanthomonas campestris pv. bilvae. A Mantel test showed that genetic distances derived from AFLP and MLSA were highly correlated. X. campestris pv. bilvae showed a close relatedness to the type strain of X. citri, indicating that this pathovar should be reclassified as X. citri pv. bilvae. All pathotype A* and A(w) strains were most closely related to X. citri pv. citri strains with a wide host range (pathotype A), confirming previous DNA-DNA hybridization data. Pathotype A(w) should be considered a junior synonym of pathotype A* on the basis of pathogenicity tests, AFLP, MLSA and PCR using pathovar-specific primers. Evolutionary genome divergences computed from AFLP data suggested that pathotype A* (including A(w) strains) is a group of strains that shows a wider genetic diversity than pathotype A.

  6. Comparative ultrastructure of nonwounded Mexican lime and Yuzu leaves infected with the citrus canker bacterium Xanthomonas citri pv. citri.

    Science.gov (United States)

    Lee, In Jung; Kim, Ki Woo; Hyun, Jae Wook; Lee, Yong Hoon; Park, Eun Woo

    2009-07-01

    Ultrastructural aspects of citrus canker development were investigated in nonwounded leaves of citrus species by transmission electron microscopy (TEM). A susceptible species Mexican lime and a resistant species Yuzu were spray-inoculated with a virulent strain of Xanthomonas citri pv. citri. Initial symptoms occurred on Mexican lime approximately 9 days after inoculation, whereas they appeared on Yuzu mostly 11 days after inoculation. In Mexican lime leaves, the bacterial invasion was usually accompanied by host cell wall dissolution and cellular disruption. Fibrillar materials from degenerated cell walls were usually found in intercellular spaces. Damaged host cells with necrotic cytoplasm showed the localized separation of plasma membrane from the cell wall. Bacterial multiplication and electron-transparent capsule-like structures around bacteria were commonly observed. Meanwhile, cell wall protuberances were prominent outside host cell walls in response to bacterial invasion in Yuzu leaves. Occlusion of intercellular spaces was also formed by the fusion of two or more individual cell wall protuberances originated from two adjacent host cells. Papillae-like materials accumulated locally within host cells in close proximity to bacteria. Some bacteria were found to be undergoing degeneration in xylem vessels. Also, the shrunken, inactive bacteria were surrounded by electron-translucent fibrillar materials in intercellular spaces, implying bacterial immobilization. These cellular responses are thought to be the consequences of defense responses of Yuzu leaves to invading bacteria. In both citrus species, X. citri pv. citri contained polyphosphate bodies showing electron-dense and elliptical structures in cytoplasm.

  7. Comparative genomics of 43 strains of Xanthomonas citri pv. citri reveals the evolutionary events giving rise to pathotypes with different host ranges.

    Science.gov (United States)

    Gordon, Jonathan L; Lefeuvre, Pierre; Escalon, Aline; Barbe, Valérie; Cruveiller, Stéphane; Gagnevin, Lionel; Pruvost, Olivier

    2015-12-23

    The identification of factors involved in the host range definition and evolution is a pivotal challenge in the goal to predict and prevent the emergence of plant bacterial disease. To trace the evolution and find molecular differences between three pathotypes of Xanthomonas citri pv. citri that may explain their distinctive host ranges, 42 strains of X. citri pv. citri and one outgroup strain, Xanthomonas citri pv. bilvae were sequenced and compared. The strains from each pathotype form monophyletic clades, with a short branch shared by the A(w) and A pathotypes. Pathotype-specific recombination was detected in seven regions of the alignment. Using Ancestral Character Estimation, 426 SNPs were mapped to the four branches at the base of the A, A*, A(w) and A/A(w) clades. Several genes containing pathotype-specific nonsynonymous mutations have functions related to pathogenicity. The A pathotype is enriched for SNP-containing genes involved in defense mechanisms, while A* is significantly depleted for genes that are involved in transcription. The pathotypes differ by four gene islands that largely coincide with regions of recombination and include genes with a role in virulence. Both A* and A(w) are missing genes involved in defense mechanisms. In contrast to a recent study, we find that there are an extremely small number of pathotype-specific gene presences and absences. The three pathotypes of X. citri pv. citri that differ in their host ranges largely show genomic differences related to recombination, horizontal gene transfer and single nucleotide polymorphism. We detail the phylogenetic relationship of the pathotypes and provide a set of candidate genes involved in pathotype-specific evolutionary events that could explain to the differences in host range and pathogenicity between them.

  8. Genetic diversity of Xanthomonas axonopodis pv. citri based on plasmid profile and pulsed field gel electrophoresis

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    Carvalho Flávia Maria de Souza

    2005-01-01

    Full Text Available Xanthomonas axonopodis pv. citri strains that cause disease in citrus were investigated by pulsed field and plasmid profile analysis. For the first method, genomic DNA was digested by the rare-cutting enzymes Xba I and Vsp I. The strains evaluated were collected in seven different States of Brazil and in Argentina, Bolivia, Paraguay and Uruguay. Genetic variability was found among strains of X. axonopodis pv. citri from different geographical areas Argentina, Bolivia and Uruguay, with similarities varying from 0.62 to 0.83. However, the strains collected in Brazil, despite being from different States, have shown a genetic similarity ranging from 0.83 to 1.00. Cluster analysis showed a relationship between genomic similarity and geographical origin of the strains. Plasmids were observed in all strains, with a total of five different plasmids, with sizes between 57.7 and 83.0 kilobases. The 72.6 kb plasmid was the most frequent, present in 15 out of 22 strains, while the 68.1 kb plasmid was observed in two strains only. Although the plasmid diversity detected in the present study was not very great, the X. axonopodis pv. citri strains evaluated showed a considerable degree of diversity with regard to this extrachromosomal genetic element.

  9. The role as inoculum sources of Xanthomonas citri pv. citri surviving on the infected Satsuma mandarin fruits.

    Science.gov (United States)

    Kang, So Young; Kim, Ki Deok; Hong, Jeum Kyu; Hyun, He Nam; Jeun, Yong Chull

    2014-05-01

    Importing citrus fruits infected by Asiatic citrus canker caused by Xanthomonas citri pv. citri (Xcc) can act as an inoculum source for the disease epidemic in citrus canker-free countries. In this study, the pathogenicity of the causal agent of Asiatic citrus canker surviving on infected Satsuma mandarin fruits was evaluated. The washing solution of infected Satsuma mandarin fruits did not cause lesion formation on the citrus leaves. However, a typical citrus canker lesion was formed on the leaves after inoculation with higher concentrations of the inoculum from the washing solution (washing solution II). It indicated that the pathogenicity of the citrus canker surviving on the symptomatic Satsuma mandarin fruits was not changed. Scanning electron microscopic observation showed that the numbers of bacterial cells on the leaves of Satsuma mandarin which inoculated with the washing solution directly (washing solution I) was less compared to those of leaves inoculated with the washing solution II. This result spports that the pathogenicity of Xcc surviving on Satsuma mandarin fruits may not be changed but that the sucessful infection of citrus caker may depend on the concentration of the inoculum.

  10. The molybdate-binding protein (ModA) of the plant pathogen Xanthomonas axonopodis pv. citri.

    Science.gov (United States)

    Balan, Andrea; Santacruz, Carolina P; Moutran, Alexandre; Ferreira, Rita C C; Medrano, Francisco J; Pérez, Carlos A; Ramos, Carlos H I; Ferreira, Luís C S

    2006-12-01

    The modABC operon of phytopathogen Xanthomonas axonopodis pv. citri (X. citri) encodes a putative ABC transporter involved in the uptake of the molybdate and tungstate anions. Sequence analyses showed high similarity values of ModA orthologs found in X. campestris pv. campestris (X. campestris) and Escherichia coli. The X. citri modA gene was cloned in pET28a and the recombinant protein, expressed in the E. coli BL21 (DE3) strain, purified by immobilized metal affinity chromatography. The purified protein remained soluble and specifically bound molybdate and tungstate with K(d) 0.29+/-0.12 microM and 0.58+/-0.14 microM, respectively. Additionally binding of molybdate drastically enhanced the thermal stability of the recombinant ModA as compared to the apoprotein. This is the first characterization of a ModA ortholog expressed by a phytopathogen and represents an important tool for functional, biochemical and structural analyses of molybdate transport in Xanthomonas species.

  11. Identification of differentially expressed genes of Xanthomonas axonopodis pv. citri by representational difference analysis of cDNA

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    Angela Mehta

    2005-03-01

    Full Text Available Xanthomonas axonopodis pv. citri is a phytopathogenic bacterium responsible for citrus canker, a serious disease which causes severe losses in citriculture around the world. In this study we report the differential expression of X. axonopodis pv. citri in response to specific treatments by using Representational Difference Analysis of cDNA (cDNA RDA. cDNAs from X. axonopodis pv. citri cultured in the presence of leaf extract of the host plant (Citrus sinensis, in vivo, as well as in the complex medium were hybridized against cDNA of the bacterium grown in the minimal medium. Sequencing of the difference products obtained after the second and third hybridizations revealed a total of 37 distinct genes identified by homology searches in the genome of X. axonopodis pv. citri. These genes were distributed in different functional categories, including genes that encode hypothetical proteins, genes involved in metabolism, cellular processes and pathogenicity, and mobile genetic elements. Most of these genes are likely related to growth and/or acquisition of nutrients in specific treatments whereas others might be important for the bacterium pathogenicity.

  12. A novel two-component response regulator links rpf with biofilm formation and virulence of Xanthomonas axonopodis pv. citri.

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    Tzu-Pi Huang

    Full Text Available Citrus bacterial canker caused by Xanthomonas axonopodis pv. citri is a serious disease that impacts citrus production worldwide, and X. axonopodis pv. citri is listed as a quarantine pest in certain countries. Biofilm formation is important for the successful development of a pathogenic relationship between various bacteria and their host(s. To understand the mechanisms of biofilm formation by X. axonopodis pv. citri strain XW19, the strain was subjected to transposon mutagenesis. One mutant with a mutation in a two-component response regulator gene that was deficient in biofilm formation on a polystyrene microplate was selected for further study. The protein was designated as BfdR for biofilm formation defective regulator. BfdR from strain XW19 shares 100% amino acid sequence identity with XAC1284 of X. axonopodis pv. citri strain 306 and 30-100% identity with two-component response regulators in various pathogens and environmental microorganisms. The bfdR mutant strain exhibited significantly decreased biofilm formation on the leaf surfaces of Mexican lime compared with the wild type strain. The bfdR mutant was also compromised in its ability to cause canker lesions. The wild-type phenotype was restored by providing pbfdR in trans in the bfdR mutant. Our data indicated that BfdR did not regulate the production of virulence-related extracellular enzymes including amylase, lipase, protease, and lecithinase or the expression of hrpG, rfbC, and katE; however, BfdR controlled the expression of rpfF in XVM2 medium, which mimics cytoplasmic fluids in planta. In conclusion, biofilm formation on leaf surfaces of citrus is important for canker development in X. axonopodis pv. citri XW19. The process is controlled by the two-component response regulator BfdR via regulation of rpfF, which is required for the biosynthesis of a diffusible signal factor.

  13. A LOV protein modulates the physiological attributes of Xanthomonas axonopodis pv. citri relevant for host plant colonization.

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    Ivana Kraiselburd

    Full Text Available Recent studies have demonstrated that an appropriate light environment is required for the establishment of efficient vegetal resistance responses in several plant-pathogen interactions. The photoreceptors implicated in such responses are mainly those belonging to the phytochrome family. Data obtained from bacterial genome sequences revealed the presence of photosensory proteins of the BLUF (Blue Light sensing Using FAD, LOV (Light, Oxygen, Voltage and phytochrome families with no known functions. Xanthomonas axonopodis pv. citri is a Gram-negative bacterium responsible for citrus canker. The in silico analysis of the X. axonopodis pv. citri genome sequence revealed the presence of a gene encoding a putative LOV photoreceptor, in addition to two genes encoding BLUF proteins. This suggests that blue light sensing could play a role in X. axonopodis pv. citri physiology. We obtained the recombinant Xac-LOV protein by expression in Escherichia coli and performed a spectroscopic analysis of the purified protein, which demonstrated that it has a canonical LOV photochemistry. We also constructed a mutant strain of X. axonopodis pv. citri lacking the LOV protein and found that the loss of this protein altered bacterial motility, exopolysaccharide production and biofilm formation. Moreover, we observed that the adhesion of the mutant strain to abiotic and biotic surfaces was significantly diminished compared to the wild-type. Finally, inoculation of orange (Citrus sinensis leaves with the mutant strain of X. axonopodis pv. citri resulted in marked differences in the development of symptoms in plant tissues relative to the wild-type, suggesting a role for the Xac-LOV protein in the pathogenic process. Altogether, these results suggest the novel involvement of a photosensory system in the regulation of physiological attributes of a phytopathogenic bacterium. A functional blue light receptor in Xanthomonas spp. has been described for the first time, showing

  14. Crystal Structure of the FAD-Containing Ferredoxin-NADP+ Reductase from the Plant Pathogen Xanthomonas axonopodis pv. citri

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    María Laura Tondo

    2013-01-01

    Full Text Available We have solved the structure of ferredoxin-NADP(H reductase, FPR, from the plant pathogen Xanthomonas axonopodis pv. citri, responsible for citrus canker, at a resolution of 1.5 Å. This structure reveals differences in the mobility of specific loops when compared to other FPRs, probably unrelated to the hydride transfer process, which contributes to explaining the structural and functional divergence between the subclass I FPRs. Interactions of the C-terminus of the enzyme with the phosphoadenosine of the cofactor FAD limit its mobility, thus affecting the entrance of nicotinamide into the active site. This structure opens the possibility of rationally designing drugs against the X. axonopodis pv. citri phytopathogen.

  15. Genomic insights into the evolutionary origin of Xanthomonas axonopodis pv. citri and its ecological relatives.

    Science.gov (United States)

    Midha, Samriti; Patil, Prabhu B

    2014-10-01

    Xanthomonas axonopodis pv. citri (Xac) is the causal agent of citrus bacterial canker (CBC) and is a serious problem worldwide. Like CBC, several important diseases in other fruits, such as mango, pomegranate, and grape, are also caused by Xanthomonas pathovars that display remarkable specificity toward their hosts. While citrus and mango diseases were documented more than 100 years ago, the pomegranate and grape diseases have been known only since the 1950s and 1970s, respectively. Interestingly, diseases caused by all these pathovars were noted first in India. Our genome-based phylogenetic studies suggest that these diverse pathogens belong to a single species and these pathovars may be just a group of rapidly evolving strains. Furthermore, the recently reported pathovars, such as those infecting grape and pomegranate, form independent clonal lineages, while the citrus and mango pathovars that have been known for a long time form one clonal lineage. Such an understanding of their phylogenomic relationship has further allowed us to understand major and unique variations in the lineages that give rise to these pathovars. Whole-genome sequencing studies including ecological relatives from their putative country of origin has allowed us to understand the evolutionary history of Xac and other pathovars that infect fruits.

  16. Pathogenic Interactions Between Xanthomonas axonopodis pv. citri and Cultivars of Pummelo (Citrus grandis).

    Science.gov (United States)

    Shiotani, H; Ozaki, K; Tsuyumu, S

    2000-12-01

    ABSTRACT The aggressiveness of strains of Xanthomonas axonopodis pv. citri on seven Citrus species, including Citrus sinensis (navel orange), C. paradisi (grapefruit), C. unshiu (Satsuma mandarin), C. junos (Yuzu), C. aurantifolia ('Mexican' lime), C. tachibana (Tachibana), and C. grandis (pummelo: 'Otachibana', 'Banpeiyu', and 'Anseikan'), were assessed by comparing lesion expansion and growth in planta, using a prick inoculation method. The existence of two groups distinct in aggressiveness was demonstrated on the pummelo cultivars, whereas the remaining species tested were uniformly susceptible. The two groups of strains were distinct in lesion expansion and growth in planta; however, both caused canker lesions on the 'Otachibana' pummelo. The sensitivity of the bacterial strains to phages Cp1 and Cp2 was associated with differences in aggressiveness. Namely, all the strains sensitive to Cp2 but resistant to Cp1 were aggressive to 'Otachibana', whereas all the strains sensitive to Cp1 but resistant to Cp2 were weakly aggressive. When a repetitive sequence-based polymerase chain reaction amplification was carried out by enterobacterial repetitive intergeneric consensus (ERIC) sequences (ERIC1R and ERIC2) as the primers, these two groups were also distinguishable by the presence or absence of a 1.8-kb DNA fragment among otherwise identical fragments. The 1.8-kb fragment was amplified only from the strains aggressive to C. grandis.

  17. Characterization of bacteriophages Cp1 and Cp2, the strain-typing agents for Xanthomonas axonopodis pv. citri.

    Science.gov (United States)

    Ahmad, Abdelmonim Ali; Ogawa, Megumi; Kawasaki, Takeru; Fujie, Makoto; Yamada, Takashi

    2014-01-01

    The strains of Xanthomonas axonopodis pv. citri, the causative agent of citrus canker, are historically classified based on bacteriophage (phage) sensitivity. Nearly all X. axonopodis pv. citri strains isolated from different regions in Japan are lysed by either phage Cp1 or Cp2; Cp1-sensitive (Cp1(s)) strains have been observed to be resistant to Cp2 (Cp2(r)) and vice versa. In this study, genomic and molecular characterization was performed for the typing agents Cp1 and Cp2. Morphologically, Cp1 belongs to the Siphoviridae. Genomic analysis revealed that its genome comprises 43,870-bp double-stranded DNA (dsDNA), with 10-bp 3'-extruding cohesive ends, and contains 48 open reading frames. The genomic organization was similar to that of Xanthomonas phage phiL7, but it lacked a group I intron in the DNA polymerase gene. Cp2 resembles morphologically Escherichia coli T7-like phages of Podoviridae. The 42,963-bp linear dsDNA genome of Cp2 contained terminal repeats. The Cp2 genomic sequence has 40 open reading frames, many of which did not show detectable homologs in the current databases. By proteomic analysis, a gene cluster encoding structural proteins corresponding to the class III module of T7-like phages was identified on the Cp2 genome. Therefore, Cp1 and Cp2 were found to belong to completely different virus groups. In addition, we found that Cp1 and Cp2 use different molecules on the host cell surface as phage receptors and that host selection of X. axonopodis pv. citri strains by Cp1 and Cp2 is not determined at the initial stage by binding to receptors.

  18. Multiplexed lateral flow microarray assay for detection of citrus pathogens Xylella fastidiosa and Xanthomonas axonopodis pv citri

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    Cary; R. Bruce (Santa Fe, NM); Stubben, Christopher J. (Los Alamos, NM)

    2011-03-22

    The invention provides highly sensitive and specific assays for the major citrus pathogens Xylella fastidiosa and Xanthomonas axonopodis, including a field deployable multiplexed assay capable of rapidly assaying for both pathogens simultaneously. The assays are directed at particular gene targets derived from pathogenic strains that specifically cause the major citrus diseases of citrus variegated chlorosis (Xylella fastidiosa 9a5c) and citrus canker (Xanthomonas axonopodis pv citri). The citrus pathogen assays of the invention offer femtomole sensitivity, excellent linear dynamic range, and rapid and specific detection.

  19. Structural-functional characterization and physiological significance of ferredoxin-NADP reductase from Xanthomonas axonopodis pv. citri.

    Science.gov (United States)

    Tondo, María Laura; Musumeci, Matías A; Delprato, María Laura; Ceccarelli, Eduardo A; Orellano, Elena G

    2011-01-01

    Xanthomonas axonopodis pv. citri is a phytopathogen bacterium that causes severe citrus canker disease. Similar to other phytopathogens, after infection by this bacterium, plants trigger a defense mechanism that produces reactive oxygen species. Ferredoxin-NADP(+) reductases (FNRs) are redox flavoenzymes that participate in several metabolic functions, including the response to reactive oxygen species. Xanthomonas axonopodis pv. citri has a gene (fpr) that encodes for a FNR (Xac-FNR) that belongs to the subclass I bacterial FNRs. The aim of this work was to search for the physiological role of this enzyme and to characterize its structural and functional properties. The functionality of Xac-FNR was tested by cross-complementation of a FNR knockout Escherichia coli strain, which exhibit high susceptibility to agents that produce an abnormal accumulation of (•)O(2)(-). Xac-FNR was able to substitute for the FNR in E. coli in its antioxidant role. The expression of fpr in X. axonopodis pv. citri was assessed using semiquantitative RT-PCR and Western blot analysis. A 2.2-fold induction was observed in the presence of the superoxide-generating agents methyl viologen and 2,3-dimethoxy-1,4-naphthoquinone. Structural and functional studies showed that Xac-FNR displayed different functional features from other subclass I bacterial FNRs. Our analyses suggest that these differences may be due to the unusual carboxy-terminal region. We propose a further classification of subclass I bacterial FNRs, which is useful to determine the nature of their ferredoxin redox partners. Using sequence analysis, we identified a ferredoxin (XAC1762) as a potential substrate of Xac-FNR. The purified ferredoxin protein displayed the typical broad UV-visible spectrum of [4Fe-4S] clusters and was able to function as substrate of Xac-FNR in the cytochrome c reductase activity. Our results suggest that Xac-FNR is involved in the oxidative stress response of Xanthomonas axonopodis pv. citri and

  20. Structural-functional characterization and physiological significance of ferredoxin-NADP reductase from Xanthomonas axonopodis pv. citri.

    Directory of Open Access Journals (Sweden)

    María Laura Tondo

    Full Text Available Xanthomonas axonopodis pv. citri is a phytopathogen bacterium that causes severe citrus canker disease. Similar to other phytopathogens, after infection by this bacterium, plants trigger a defense mechanism that produces reactive oxygen species. Ferredoxin-NADP(+ reductases (FNRs are redox flavoenzymes that participate in several metabolic functions, including the response to reactive oxygen species. Xanthomonas axonopodis pv. citri has a gene (fpr that encodes for a FNR (Xac-FNR that belongs to the subclass I bacterial FNRs. The aim of this work was to search for the physiological role of this enzyme and to characterize its structural and functional properties. The functionality of Xac-FNR was tested by cross-complementation of a FNR knockout Escherichia coli strain, which exhibit high susceptibility to agents that produce an abnormal accumulation of (•O(2(-. Xac-FNR was able to substitute for the FNR in E. coli in its antioxidant role. The expression of fpr in X. axonopodis pv. citri was assessed using semiquantitative RT-PCR and Western blot analysis. A 2.2-fold induction was observed in the presence of the superoxide-generating agents methyl viologen and 2,3-dimethoxy-1,4-naphthoquinone. Structural and functional studies showed that Xac-FNR displayed different functional features from other subclass I bacterial FNRs. Our analyses suggest that these differences may be due to the unusual carboxy-terminal region. We propose a further classification of subclass I bacterial FNRs, which is useful to determine the nature of their ferredoxin redox partners. Using sequence analysis, we identified a ferredoxin (XAC1762 as a potential substrate of Xac-FNR. The purified ferredoxin protein displayed the typical broad UV-visible spectrum of [4Fe-4S] clusters and was able to function as substrate of Xac-FNR in the cytochrome c reductase activity. Our results suggest that Xac-FNR is involved in the oxidative stress response of Xanthomonas axonopodis pv

  1. Differential expression of pathogenicity- and virulence-related genes of Xanthomonas axonopodis pv. citri under copper stress

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    Ana Carolina Basílio Palmieri

    2010-01-01

    Full Text Available In this study, we used real-time quantitative PCR (RT-qPCR to evaluate the expression of 32 genes of Xanthomonas axonopodis pv. citri related to pathogenicity and virulence that are also involved in copper detoxification. Nearly all of the genes were up-regulated, including copA and copB. Two genes homologous to members of the type II secretion system (xcsH and xcsC and two involved in the degradation of plant cell wall components (pglA and pel were the most expressed in response to an elevated copper concentration. The type II secretion system (xcs operon and a few homologues of proteins putatively secreted by this system showed enhanced expression when the bacteria were exposed to a high concentration of copper sulfate. The enhanced expression of the genes of secretion II system during copper stress suggests that this pathway may have an important role in the adaptative response of X. axonopodis pv. citri to toxic compounds. These findings highlight the potential role of these genes in attenuating the toxicity of certain metals and could represent an important means of bacterial resistance against chemicals used to control diseases.

  2. Crystallization, data collection and phasing of the molybdate-binding protein of the phytopathogen Xanthomonas axonopodis pv. citri

    Energy Technology Data Exchange (ETDEWEB)

    Santacruz, C. P.; Balan, A.; Ferreira, L. C. S. [Departamento de Microbiologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, São Paulo, SP (Brazil); Barbosa, J. A. R. G., E-mail: joao@lnls.br [Centro de Biologia Molecular e Estrutural (CeBiMe), Laboratório Nacional de Luz Síncrotron (LNLS), CP 6192, Campinas, SP 13084-971 (Brazil); Departamento de Microbiologia, Instituto de Ciências Biomédicas II, Universidade de São Paulo, São Paulo, SP (Brazil)

    2006-03-01

    The molybdate-binding protein (ModA) from X. axonopodis pv. citri was crystallized with sodium molybdate in the presence of PEG or sulfate. The crystal diffracted to a maximum resolution of 1.7 Å and belongs to the orthorhombic space group C222{sub 1,} with unit-cell parameters a = 68.15, b = 172.14, c = 112.04 Å. Xanthomonas axonopodis pv. citri ModA protein is the ABC periplasmic binding component responsible for the capture of molybdate. The protein was crystallized with sodium molybdate using the hanging-drop vapour-diffusion method in the presence of PEG or sulfate. X-ray diffraction data were collected to a maximum resolution of 1.7 Å using synchrotron radiation. The crystal belongs to the orthorhombic space group C222{sub 1}, with unit-cell parameters a = 68.15, b = 172.14, c = 112.04 Å. The crystal structure was solved by molecular-replacement methods and structure refinement is in progress.

  3. Crystallographic structure and substrate-binding interactions of the molybdate-binding protein of the phytopathogen Xanthomonas axonopodis pv. citri.

    Science.gov (United States)

    Balan, Andrea; Santacruz-Pérez, Carolina; Moutran, Alexandre; Ferreira, Luís Carlos Souza; Neshich, Goran; Gonçalves Barbosa, João Alexandre Ribeiro

    2008-02-01

    In Xanthomonas axonopodis pv. citri (Xac or X. citri), the modA gene codes for a periplasmic protein (ModA) that is capable of binding molybdate and tungstate as part of the ABC-type transporter required for the uptake of micronutrients. In this study, we report the crystallographic structure of the Xac ModA protein with bound molybdate. The Xac ModA structure is similar to orthologs with known three-dimensional structures and consists of two nearly symmetrical domains separated by a hinge region where the oxyanion-binding site lies. Phylogenetic analysis of different ModA orthologs based on sequence alignments revealed three groups of molybdate-binding proteins: bacterial phytopathogens, enterobacteria and soil bacteria. Even though the ModA orthologs are segregated into different groups, the ligand-binding hydrogen bonds are mostly conserved, except for Archaeglobus fulgidus ModA. A detailed discussion of hydrophobic interactions in the active site is presented and two new residues, Ala38 and Ser151, are shown to be part of the ligand-binding pocket.

  4. Monitoramento da expressão gênica de Xanthomonas axonopodis pv. citri em diferentes condições ambientais

    OpenAIRE

    2003-01-01

    The bacterium Xanthomonas axonopodis pv. citri is a pathogen causing citric canker that compromises part of the orange production in the State of São Paulo, with negative consequences for the economy of the State and the Country. For the future control of citric canker, several investigators participated in the Xanthomonas Genome Project in order to determine the gene set of this bacterium and to contribute to the identification of the genes involved in its pathogenicity. In this respect, the...

  5. Construction of EGFP-labeling system for visualizing the infection process of Xanthomonas axonopodis pv. citri in planta.

    Science.gov (United States)

    Liu, Li-Ping; Deng, Zi-Niu; Qu, Jin-Wang; Yan, Jia-Wen; Catara, Vittoria; Li, Da-Zhi; Long, Gui-You; Li, Na

    2012-09-01

    Xanthomonas axonopodis pv. citri (Xac) is the causal agent of citrus bacterial canker, an economically important disease to world citrus industry. To monitor the infection process of Xac in different citrus plants, the enhanced green florescent protein (EGFP) visualizing system was constructed to visualize the propagation and localization in planta. First, the wild-type Xac was isolated from the diseased leaves of susceptible 'Bingtang' sweet orange, and then the isolated Xac was labeled with EGFP by triparental mating. After PCR identification, the growth kinetics and pathogenicity of the transformants were analyzed in comparison with the wild-type Xac. The EGFP-labeled bacteria were inoculated by spraying on the surface and infiltration in the mesophyll of 'Bingtang' sweet orange leaves. The bacterial cell multiplication and diffusion processes were observed directly under confocal laser scanning microscope at different intervals after inoculation. The results indicated that the EGFP-labeled Xac releasing clear green fluorescence light under fluorescent microscope showed the infection process and had the same pathogenicity as the wild type to citrus. Consequently, the labeled Xac demonstrated the ability as an efficient tool to monitor the pathogen infection.

  6. Genome-wide mutagenesis of Xanthomonas axonopodis pv. citri reveals novel genetic determinants and regulation mechanisms of biofilm formation.

    Directory of Open Access Journals (Sweden)

    Jinyun Li

    Full Text Available Xanthomonas axonopodis pv. citri (Xac causes citrus canker disease, a major threat to citrus production worldwide. Accumulating evidence suggests that the formation of biofilms on citrus leaves plays an important role in the epiphytic survival of this pathogen prior to the development of canker disease. However, the process of Xac biofilm formation is poorly understood. Here, we report a genome-scale study of Xac biofilm formation in which we identified 92 genes, including 33 novel genes involved in biofilm formation and 7 previously characterized genes, colR, fhaB, fliC, galU, gumD, wxacO, and rbfC, known to be important for Xac biofilm formation. In addition, 52 other genes with defined or putative functions in biofilm formation were identified, even though they had not previously reported been to be associated with biofilm formation. The 92 genes were isolated from 292 biofilm-defective mutants following a screen of a transposon insertion library containing 22,000 Xac strain 306 mutants. Further analyses indicated that 16 of the novel genes are involved in the production of extracellular polysaccharide (EPS and/or lipopolysaccharide (LPS, 7 genes are involved in signaling and regulatory pathways, and 5 genes have unknown roles in biofilm formation. Furthermore, two novel genes, XAC0482, encoding a haloacid dehalogenase-like phosphatase, and XAC0494 (designated as rbfS, encoding a two-component sensor protein, were confirmed to be biofilm-related genes through complementation assays. Our data demonstrate that the formation of mature biofilm requires EPS, LPS, both flagellum-dependent and flagellum-independent cell motility, secreted proteins and extracellular DNA. Additionally, multiple signaling pathways are involved in Xac biofilm formation. This work is the first report on a genome-wide scale of the genetic processes of biofilm formation in plant pathogenic bacteria. The report provides significant new information about the genetic

  7. In silico identification of potential chaperone genes that belong to type III and type IV secretion systems in Xanthomonas axonopodis pv citri

    Directory of Open Access Journals (Sweden)

    Letícia Khater

    2005-01-01

    Full Text Available The secretion of bacterial virulence factors and flagellar components requires the assistance of specific type III and flagellar chaperones. Standard computational annotation of the genome of Xanthomonas axonopodis pv citri, a plant pathogen that causes citrus canker, initially did not identify any genes belonging to these chaperone categories since the primary sequence homology between them was very low. However, in a search for hypothetical proteins with characteristics similar to these chaperones, we have now identified 30 chromosomal and 10 plasmidial potential genes encoding chaperones belonging to types III/IV, and flagellar secretion systems in this organism. The significance of these findings is discussed.

  8. The monofunctional catalase KatE of Xanthomonas axonopodis pv. citri is required for full virulence in citrus plants.

    Directory of Open Access Journals (Sweden)

    María Laura Tondo

    Full Text Available BACKGROUND: Xanthomonas axonopodis pv. citri (Xac is an obligate aerobic phytopathogen constantly exposed to hydrogen peroxide produced by normal aerobic respiration and by the plant defense response during plant-pathogen interactions. Four putative catalase genes have been identified in silico in the Xac genome, designated as katE, catB, srpA (monofunctional catalases and katG (bifunctional catalase. METHODOLOGY/PRINCIPAL FINDINGS: Xac catalase activity was analyzed using native gel electrophoresis and semi-quantitative RT-PCR. We demonstrated that the catalase activity pattern was regulated in different growth stages displaying the highest levels during the stationary phase. KatE was the most active catalase in this phase of growth. At this stage cells were more resistant to hydrogen peroxide as was determined by the analysis of CFU after the exposition to different H(2O(2 concentrations. In addition, Xac exhibited an adaptive response to hydrogen peroxide, displaying higher levels of catalase activity and H(2O(2 resistance after treatment with sub-lethal concentrations of the oxidant. In the plant-like medium XVM2 the expression of KatE was strongly induced and in this medium Xac was more resistant to H(2O(2. A XackatE mutant strain was constructed by insertional mutagenesis. We observed that catalase induction in stationary phase was lost meanwhile the adaptive response to peroxide was maintained in this mutant. Finally, the XackatE strain was assayed in planta during host plant interaction rendering a less aggressive phenotype with a minor canker formation. CONCLUSIONS: Our results confirmed that in contrast to other Xanthomonas species, Xac catalase-specific activity is induced during the stationary phase of growth in parallel with the bacterial resistance to peroxide challenge. Moreover, Xac catalases expression pattern is modified in response to any stimuli associated with the plant or the microenvironment it provides. The catalase Kat

  9. Comparison of PCR,DIA and Pathogenicity Assay for Detection of Xanthomonas axonopodis pv.citri,the Causal Agent of Citrus Bacterial Canker Disease

    Institute of Scientific and Technical Information of China (English)

    WANG Zhong-kang; SUN Xian-yun; YIN You-ping; ZHOU Chang-yong; XIA Yu-xian

    2004-01-01

    Polymerase chain reaction (PCR) approach based on newly designed primers, JYF5/JYR5, was applied for specific detection of Xanthomonas axonopodis pv.citri(Xac). The efficiency and reliability of PCR method were compared with dot immunobinding assay (DIA) and classical pathogenicity test techniques for detecting suspensions of pure cells of Xac and soaking sap of citrus tissues. Detection sensitivity of PCR was about 4.5 cells or 1.56 pg target DNA per reaction which was higher than that of DIA (ca. 450 cells per dot).These three techniques (PCR assay, DIA and Pathogenecity test) could always detect Xac from symptomatic citrus samples. Different performances were obtained from citrus materials without symptoms, and the positive detection frequency was PCR, DIA and pathogenicity test.

  10. Xanthomonas axonopodis pv. citri YaeQ structure reveals new compact protein fold built around a variation of the PD-(D/E)XK nuclease motif

    Energy Technology Data Exchange (ETDEWEB)

    Guzzo, Cristiane Rodrigues; Farah, Chuck Shaker [Universidade de Sao Paulo (USP), SP (Brazil). Inst. de Quimica. Dept. de Bioquimica; Nagem, Ronaldo Alves Pinto [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Inst. de Ciencias Biologicas. Dept. de Bioquimica e Imunologia; Barbosa, Joao Alexandre Ribeiro Goncalves [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil). Centro de Biologia Molecular Estrutural

    2008-11-15

    The YaeQ family of proteins derives from close to two hundred species of Gram-negative bacteria. Despite their widespread distribution, their molecular and physiological functions are unknown. We used X-ray crystallography and multi-wavelength anomalous dispersion to determine the high resolution structure of the YaeQ protein (XAC2398) from the phytopathogen Xanthomonas axonopodis pv. citri. The novel structure revealed that YaeQ pertains to the PD-(D/E)XK superfamily of metal-dependent endonucleases. The phylogenetic distribution of YaeQ proteins and a detailed comparison of the YaeQ structure with that of other PD-(D/E)XK family members point to specific testable hypotheses regarding YaeQ function. (author)

  11. The filamentous phage XacF1 causes loss of virulence in Xanthomonas axonopodis pv. citri, the causative agent of citrus canker disease

    Directory of Open Access Journals (Sweden)

    Abdelmonim Ali Ahmad

    2014-07-01

    Full Text Available In this study, filamentous phage XacF1, which can infect Xanthomonas axonopodis pv. citri (Xac strains, was isolated and characterized. Electron microscopy showed that XacF1 is a member of the family Inoviridae and is about 1000 nm long and 16 nm in width. The genome of XacF1 is 7325 nucleotides in size, containing 13 predicted open reading frames (ORFs, some of which showed significant homology to Ff-like phage proteins such as ORF1 (pII, ORF2 (pV, ORF6 (pIII, and ORF8 (pVI. XacF1 showed a relatively wide host range, infecting seven out of 11 strains tested in this study. Frequently, XacF1 was found to be integrated into the genome of Xac strains. This integration occurred at the host dif site (attB and was mediated by the host XerC/D recombination system. The attP sequence was identical to that of Xanthomonas phage Cf1c. Interestingly, infection by XacF1 phage caused several physiological changes to the bacterial host cells, including lower levels of extracellular polysaccharide production, reduced motility, slower growth rate, and a dramatic reduction in virulence. In particular, the reduction in virulence suggested possible utilization of XacF1 as a biological control agent against citrus canker disease.

  12. Development and validation of a Xanthomonas axonopodis pv. citri DNA microarray platform (XACarray generated from the shotgun libraries previously used in the sequencing of this bacterial genome

    Directory of Open Access Journals (Sweden)

    Zaini Paulo A

    2010-05-01

    Full Text Available Abstract Background From shotgun libraries used for the genomic sequencing of the phytopathogenic bacterium Xanthomonas axonopodis pv. citri (XAC, clones that were representative of the largest possible number of coding sequences (CDSs were selected to create a DNA microarray platform on glass slides (XACarray. The creation of the XACarray allowed for the establishment of a tool that is capable of providing data for the analysis of global genome expression in this organism. Findings The inserts from the selected clones were amplified by PCR with the universal oligonucleotide primers M13R and M13F. The obtained products were purified and fixed in duplicate on glass slides specific for use in DNA microarrays. The number of spots on the microarray totaled 6,144 and included 768 positive controls and 624 negative controls per slide. Validation of the platform was performed through hybridization of total DNA probes from XAC labeled with different fluorophores, Cy3 and Cy5. In this validation assay, 86% of all PCR products fixed on the glass slides were confirmed to present a hybridization signal greater than twice the standard deviation of the deviation of the global median signal-to-noise ration. Conclusions Our validation of the XACArray platform using DNA-DNA hybridization revealed that it can be used to evaluate the expression of 2,365 individual CDSs from all major functional categories, which corresponds to 52.7% of the annotated CDSs of the XAC genome. As a proof of concept, we used this platform in a previously work to verify the absence of genomic regions that could not be detected by sequencing in related strains of Xanthomonas.

  13. A plant natriuretic peptide-like molecule of the pathogen Xanthomonas axonopodis pv. citri causes rapid changes in the proteome of its citrus host

    Directory of Open Access Journals (Sweden)

    Ottado Jorgelina

    2010-03-01

    Full Text Available Abstract Background Plant natriuretic peptides (PNPs belong to a novel class of peptidic signaling molecules that share some structural similarity to the N-terminal domain of expansins and affect physiological processes such as water and ion homeostasis at nano-molar concentrations. The citrus pathogen Xanthomonas axonopodis pv. citri possesses a PNP-like peptide (XacPNP uniquely present in this bacteria. Previously we observed that the expression of XacPNP is induced upon infection and that lesions produced in leaves infected with a XacPNP deletion mutant were more necrotic and lead to earlier bacterial cell death, suggesting that the plant-like bacterial PNP enables the plant pathogen to modify host responses in order to create conditions favorable to its own survival. Results Here we measured chlorophyll fluorescence parameters and water potential of citrus leaves infiltrated with recombinant purified XacPNP and demonstrate that the peptide improves the physiological conditions of the tissue. Importantly, the proteomic analysis revealed that these responses are mirrored by rapid changes in the host proteome that include the up-regulation of Rubisco activase, ATP synthase CF1 α subunit, maturase K, and α- and β-tubulin. Conclusions We demonstrate that XacPNP induces changes in host photosynthesis at the level of protein expression and in photosynthetic efficiency in particular. Our findings suggest that the biotrophic pathogen can use the plant-like hormone to modulate the host cellular environment and in particular host metabolism and that such modulations weaken host defence.

  14. A plant natriuretic peptide-like molecule of the pathogen Xanthomonas axonopodis pv. citri causes rapid changes in the proteome of its citrus host

    KAUST Repository

    Garavaglia, Betiana S

    2010-03-21

    Background: Plant natriuretic peptides (PNPs) belong to a novel class of peptidic signaling molecules that share some structural similarity to the N-terminal domain of expansins and affect physiological processes such as water and ion homeostasis at nano-molar concentrations. The citrus pathogen Xanthomonas axonopodis pv. citri possesses a PNP-like peptide (XacPNP) uniquely present in this bacteria. Previously we observed that the expression of XacPNP is induced upon infection and that lesions produced in leaves infected with a XacPNP deletion mutant were more necrotic and lead to earlier bacterial cell death, suggesting that the plant-like bacterial PNP enables the plant pathogen to modify host responses in order to create conditions favorable to its own survival.Results: Here we measured chlorophyll fluorescence parameters and water potential of citrus leaves infiltrated with recombinant purified XacPNP and demonstrate that the peptide improves the physiological conditions of the tissue. Importantly, the proteomic analysis revealed that these responses are mirrored by rapid changes in the host proteome that include the up-regulation of Rubisco activase, ATP synthase CF1 ? subunit, maturase K, and ?- and ?-tubulin.Conclusions: We demonstrate that XacPNP induces changes in host photosynthesis at the level of protein expression and in photosynthetic efficiency in particular. Our findings suggest that the biotrophic pathogen can use the plant-like hormone to modulate the host cellular environment and in particular host metabolism and that such modulations weaken host defence. 2010 Garavaglia et al; licensee BioMed Central Ltd.

  15. Regular LAMP and fast LAMP for the detection of Xanthomonas axonopodis pv.citri%柑橘溃疡病菌的普通LAMP及快速LAMP检测方法的建立

    Institute of Scientific and Technical Information of China (English)

    张仑; 殷幼平; 吴瑜佳; 王中康

    2013-01-01

    This study is aimed to establish the regular LAMP and fast LAMP for the detection of Xanthomonas axonopodis pv.citri and make it useful for the grassroots quarantine departments.A specific region of the genome of X.axonopodis pv.citri was used for the design of regular LAMP and fast LAMP primers; the regular LAMP and fast LAMP detection system were established by optimization of reaction conditions; the specificity of the system was verified using genomic DNA of several reference strains and healthy citrus leaves by using a series of gradient dilution of DNA solution of X.axonopodis pv.citri and bacterial suspension.Bacterial suspension and DNA sensitivity of regular LAMP system reached 2.25 × 104 cfu and 2.03× 10-1 ng,respectively,while those of fast LAMP system reached 2.25 cfu and 2.03× 10-5 ng,respectively.In the specificity test,both regular LAMP and fast LAMP system showed high and identical specificity.The total time for the fast LAMP reaction was within 30 minutes,only half of that for the regular LAMP,greatly improving the efficiency of the analysis.The fast LAMP system was ten thousand times as sensitive as the regular LAMP system.Regular LAMP and fast LAMP for the detection of X.axonopodis pv.citri was successfully established.Regular LAMP and fast LAMP system provide a new,fast and easy way for the detection of X.axonopodis pv.citri.%建立柑橘溃疡病菌的普通LAMP和快速LAMP检测方法,使其能应用于基层检验检疫部门对病害的快速检测.利用柑橘溃疡病菌基因组特有的保守区域设计LAMP引物,通过优化反应条件,建立柑橘溃疡病菌的普通LAMP检测体系;在普通LAMP引物的基础上设计一对环引物,建立柑橘溃疡病菌的快速LAMP检测体系,并以多种参比菌DNA以及健康柑橘叶片基因组DNA为模板对普通LAMP和快速LAMP检测体系的特异性进行了验证,利用柑橘溃疡病菌菌液和DNA溶液梯度稀释液对普通LAMP和快速LAMP检测体系的灵敏度进

  16. Microwave-based Method for Genomic DNA Extraction and Rapid Detection Method from Xanthomonas axonopodis pv.citri%柑桔溃疡病菌基因组DNA的微波法抽提及快速检测

    Institute of Scientific and Technical Information of China (English)

    姚廷山; 周常勇; 胡军华; 冉春; 李鸿筠; 刘浩强; 肖田

    2012-01-01

    利用微波热震惊提取固体表面柑桔溃疡病基因组DNA并加以优化,所得到的基因组DNA可作为PCR反应的模板进行16SrDNA基因有效扩增.与柑桔溃疡病基园组DNA其他抽提方法相比较,微波法更适用于该病的快速检测,具有快速、筒便、费用低廉等特点,且对设备的要求不高,用特异性引物XCF/XCR可实现柑桔溃疡病菌的快速鉴定.%The optimized microwave extraction was conducted to attract the genome of citrus canker disease. The genome extraction method was fast,easy to handle with low cost The extracted DNA was suitable for PCR. The microwave-based method was suitable for fast identification compare to other methods. The method was effective, easy and fast, so it was recommended that the extraction method was applied for the detection of Xanthomonas oxonopodit pv. citri using primers XCF/XCR.

  17. The type III protein secretion system contributes to Xanthomonas citri subsp. citri biofilm formation

    KAUST Repository

    Zimaro, Tamara

    2014-04-18

    Background: Several bacterial plant pathogens colonize their hosts through the secretion of effector proteins by a Type III protein secretion system (T3SS). The role of T3SS in bacterial pathogenesis is well established but whether this system is involved in multicellular processes, such as bacterial biofilm formation has not been elucidated. Here, the phytopathogen Xanthomonas citri subsp. citri (X. citri) was used as a model to gain further insights about the role of the T3SS in biofilm formation. Results: The capacity of biofilm formation of different X. citri T3SS mutants was compared to the wild type strain and it was observed that this secretion system was necessary for this process. Moreover, the T3SS mutants adhered proficiently to leaf surfaces but were impaired in leaf-associated growth. A proteomic study of biofilm cells showed that the lack of the T3SS causes changes in the expression of proteins involved in metabolic processes, energy generation, exopolysaccharide (EPS) production and bacterial motility as well as outer membrane proteins. Furthermore, EPS production and bacterial motility were also altered in the T3SS mutants. Conclusions: Our results indicate a novel role for T3SS in X. citri in the modulation of biofilm formation. Since this process increases X. citri virulence, this study reveals new functions of T3SS in pathogenesis. 2014 Zimaro et al.; licensee BioMed Central Ltd.

  18. Fortunella margarita Transcriptional Reprogramming Triggered by Xanthomonas citri subsp. citri

    Directory of Open Access Journals (Sweden)

    Khalaf Abeer A

    2011-11-01

    Full Text Available Abstract Background Citrus canker disease caused by the bacterial pathogen Xanthomonas citri subsp. citri (Xcc has become endemic in areas where high temperature, rain, humidity, and windy conditions provide a favourable environment for the dissemination of the bacterium. Xcc is pathogenic on many commercial citrus varieties but appears to elicit an incompatible reaction on the citrus relative Fortunella margarita Swing (kumquat, in the form of a very distinct delayed necrotic response. We have developed subtractive libraries enriched in sequences expressed in kumquat leaves during both early and late stages of the disease. The isolated differentially expressed transcripts were subsequently sequenced. Our results demonstrate how the use of microarray expression profiling can help assign roles to previously uncharacterized genes and elucidate plant pathogenesis-response related mechanisms. This can be considered to be a case study in a citrus relative where high throughput technologies were utilized to understand defence mechanisms in Fortunella and citrus at the molecular level. Results cDNAs from sequenced kumquat libraries (ESTs made from subtracted RNA populations, healthy vs. infected, were used to make this microarray. Of 2054 selected genes on a customized array, 317 were differentially expressed (P Conclusion Functional categorization of kumquat Xcc-responsive genes revealed an enhanced defence-related metabolism as well as a number of resistant response-specific genes in the kumquat transcriptome in response to Xcc inoculation. Gene expression profile(s were analyzed to assemble a comprehensive and inclusive image of the molecular interaction in the kumquat/Xcc system. This was done in order to elucidate molecular mechanisms associated with the development of the hypersensitive response phenotype in kumquat leaves. These data will be used to perform comparisons among citrus species to evaluate means to enhance the host immune responses

  19. Comparative genomic analysis of Xanthomonas axonopodis pv. citrumelo F1, which causes citrus bacterial spot disease, and related strains provides insights into virulence and host specificity.

    Science.gov (United States)

    Jalan, Neha; Aritua, Valente; Kumar, Dibyendu; Yu, Fahong; Jones, Jeffrey B; Graham, James H; Setubal, João C; Wang, Nian

    2011-11-01

    Xanthomonas axonopodis pv. citrumelo is a citrus pathogen causing citrus bacterial spot disease that is geographically restricted within the state of Florida. Illumina, 454 sequencing, and optical mapping were used to obtain a complete genome sequence of X. axonopodis pv. citrumelo strain F1, 4.9 Mb in size. The strain lacks plasmids, in contrast to other citrus Xanthomonas pathogens. Phylogenetic analysis revealed that this pathogen is very close to the tomato bacterial spot pathogen X. campestris pv. vesicatoria 85-10, with a completely different host range. We also compared X. axonopodis pv. citrumelo to the genome of citrus canker pathogen X. axonopodis pv. citri 306. Comparative genomic analysis showed differences in several gene clusters, like those for type III effectors, the type IV secretion system, lipopolysaccharide synthesis, and others. In addition to pthA, effectors such as xopE3, xopAI, and hrpW were absent from X. axonopodis pv. citrumelo while present in X. axonopodis pv. citri. These effectors might be responsible for survival and the low virulence of this pathogen on citrus compared to that of X. axonopodis pv. citri. We also identified unique effectors in X. axonopodis pv. citrumelo that may be related to the different host range as compared to that of X. axonopodis pv. citri. X. axonopodis pv. citrumelo also lacks various genes, such as syrE1, syrE2, and RTX toxin family genes, which were present in X. axonopodis pv. citri. These may be associated with the distinct virulences of X. axonopodis pv. citrumelo and X. axonopodis pv. citri. Comparison of the complete genome sequence of X. axonopodis pv. citrumelo to those of X. axonopodis pv. citri and X. campestris pv. vesicatoria provides valuable insights into the mechanism of bacterial virulence and host specificity.

  20. Comparative Genomic Analysis of Xanthomonas axonopodis pv. citrumelo F1, Which Causes Citrus Bacterial Spot Disease, and Related Strains Provides Insights into Virulence and Host Specificity ▿ #

    Science.gov (United States)

    Jalan, Neha; Aritua, Valente; Kumar, Dibyendu; Yu, Fahong; Jones, Jeffrey B.; Graham, James H.; Setubal, João C.; Wang, Nian

    2011-01-01

    Xanthomonas axonopodis pv. citrumelo is a citrus pathogen causing citrus bacterial spot disease that is geographically restricted within the state of Florida. Illumina, 454 sequencing, and optical mapping were used to obtain a complete genome sequence of X. axonopodis pv. citrumelo strain F1, 4.9 Mb in size. The strain lacks plasmids, in contrast to other citrus Xanthomonas pathogens. Phylogenetic analysis revealed that this pathogen is very close to the tomato bacterial spot pathogen X. campestris pv. vesicatoria 85-10, with a completely different host range. We also compared X. axonopodis pv. citrumelo to the genome of citrus canker pathogen X. axonopodis pv. citri 306. Comparative genomic analysis showed differences in several gene clusters, like those for type III effectors, the type IV secretion system, lipopolysaccharide synthesis, and others. In addition to pthA, effectors such as xopE3, xopAI, and hrpW were absent from X. axonopodis pv. citrumelo while present in X. axonopodis pv. citri. These effectors might be responsible for survival and the low virulence of this pathogen on citrus compared to that of X. axonopodis pv. citri. We also identified unique effectors in X. axonopodis pv. citrumelo that may be related to the different host range as compared to that of X. axonopodis pv. citri. X. axonopodis pv. citrumelo also lacks various genes, such as syrE1, syrE2, and RTX toxin family genes, which were present in X. axonopodis pv. citri. These may be associated with the distinct virulences of X. axonopodis pv. citrumelo and X. axonopodis pv. citri. Comparison of the complete genome sequence of X. axonopodis pv. citrumelo to those of X. axonopodis pv. citri and X. campestris pv. vesicatoria provides valuable insights into the mechanism of bacterial virulence and host specificity. PMID:21908674

  1. Development of RLK-Derived Molecular Markers Associating with the Resistance to Citrus Canker [Xanthomonas axonopodis pv. Citri (Xac)] Disease%开发与柑桔抗溃疡病基因连锁的由RLK-RGC衍生的分子标记

    Institute of Scientific and Technical Information of China (English)

    向旭; 郑启发; 黄舒; 陈存贤; Frederick G. Gmitter Jr.; 邓占鳌

    2005-01-01

    本文是在先期研究工作的基础上,利用从柑桔与枳属间杂种的基因组DNA所获得的类受体激酶(RLK)的候选抗病基因序列,重新设计引物,对柑桔抗溃疡病材料和感病材料开展以PCR扩增为基础的对比分析,其中一对引物‘19h16/DdeI'的扩增产物经限制性内切酶DdeI酶切,揭示了抗性材料(Ichang Papeda,Meiwa kumquat,Maruhi kumquat and Nagami kumquat)和感病材料(Flying Dragon,Valencia orange and Palestine sweetlime)之间的多态性差异,同时,在C.Ichangensis的自交F1代和Palestine sweetlime× Ichang Papeda的杂交F1代群体中也见明显的多态性差异;对这些F1代个体进行溃疡病病原[Xanthomonas axonopodis pv.Citri(Xac)]接种作抗病性表型鉴定,结果表明,该分子标记‘19h16/DdeI'与柑桔溃疡病抗性密切相关;经纯化测序的结果进一步证明,抗性材料PCR扩增产物具有完全一致的序列和DdeI酶切位点,但感病材料缺少这一DdeI酶切位点;染色体步行(primerwalking)在BAC文库的对应单克隆中获得了一个完整的抗病基因序列,与以前获得的2个抗病基因序列‘17o6RLKP'和‘26m19RLKP'相比,‘19h16RLKP'也具有Xa21抗病基因蛋白的所有特征,包括含有一个信号肽、同样数目的亮氨酸重复序列、跨膜域和激酶域等.基于该序列的开放读码框,发展了特异性更强可靠性更高的另一分子标记,在今后的研究工作中具有较大的应用潜力.%By utilizing the receptor-like kinase (RLK) RGC sequences previously obtained from the genomic DNA of an intergeneric Citrus and Poncirus hybrid, PCR amplification with one pair of new-designed primers was found to reveal polymorphism between the theoretical resistant species (Ichang Papeda, Meiwa kumquat,Maruhi kumquat and Nagami kumquat) and susceptible species (Flying Dragon, Valencia orange and Palestine sweet lime ) and among the self-crossing population of C. Ichangensis and F1 population of Palestine sweet lime

  2. Proposal to conserve the name Phomopsis citri H.S. Fawc. (Diaporthe citri), with a conserved type, against Phomopsis citri (Sacc.) Traverso & Spessa (Ascomycota, Diaporthales, Diaporthaceae)

    Science.gov (United States)

    The name Diaporthe citri applies to a fungus that causes a disease on Citrus known as melanose or stem end rot of mature fruit after harvest and occurs widely in North America and Asia. Initially described as the illegitimate Phomopsis citri H.S. Fawc. 1912, non P. citri (Sacc.) Traverso & Spessa 19...

  3. Foliar application of biofilm formation-inhibiting compounds enhances control of citrus canker caused by Xanthomonas citri subsp. citri.

    Science.gov (United States)

    Li, Jinyun; Wang, Nian

    2014-02-01

    Citrus canker caused by the bacterium Xanthomonas citri subsp. citri is an economically important disease of citrus worldwide. Biofilm formation plays an important role in early infection of X. citri subsp. citri on host leaves. In this study, we assessed the hypothesis that small molecules inhibiting biofilm formation reduce X. citri subsp. citri infection and enhance the control of citrus canker disease. D-leucine and 3-indolylacetonitrile (IAN) were found to prevent biofilm formation by X. citri subsp. citri on different abiotic surfaces and host leaves at a concentration lower than the minimum inhibitory concentration (MIC). Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis indicated that IAN repressed expression of chemotaxis/motility-related genes in X. citri subsp. citri. In laboratory experiments, planktonic and biofilm cells of X. citri subsp. citri treated with D-leucine and IAN, either alone or in combination, were more susceptible to copper (CuSO4) than those untreated. In greenhouse assays, D-leucine and IAN applied alone or combined with copper reduced both the number of canker lesions and bacterial populations of X. citri subsp. citri on citrus host leaves. This study provides the basis for the use of foliar-applied biofilm inhibitors for the control of citrus canker alone or combined with copper-based bactericides.

  4. Structural and Physiological Analyses of the Alkanesulphonate-Binding Protein (SsuA) of the Citrus Pathogen Xanthomonas citri

    Science.gov (United States)

    Tófoli de Araújo, Fabiano; Bolanos-Garcia, Victor M.; Pereira, Cristiane T.; Sanches, Mario; Oshiro, Elisa E.; Ferreira, Rita C. C.; Chigardze, Dimitri Y.; Barbosa, João Alexandre Gonçalves; de Souza Ferreira, Luís Carlos; Benedetti, Celso E.; Blundell, Tom L.; Balan, Andrea

    2013-01-01

    Background The uptake of sulphur-containing compounds plays a pivotal role in the physiology of bacteria that live in aerobic soils where organosulfur compounds such as sulphonates and sulphate esters represent more than 95% of the available sulphur. Until now, no information has been available on the uptake of sulphonates by bacterial plant pathogens, particularly those of the Xanthomonas genus, which encompasses several pathogenic species. In the present study, we characterised the alkanesulphonate uptake system (Ssu) of Xanthomonas axonopodis pv. citri 306 strain (X. citri), the etiological agent of citrus canker. Methodology/Principal Findings A single operon-like gene cluster (ssuEDACB) that encodes both the sulphur uptake system and enzymes involved in desulphurisation was detected in the genomes of X. citri and of the closely related species. We characterised X. citri SsuA protein, a periplasmic alkanesulphonate-binding protein that, together with SsuC and SsuB, defines the alkanesulphonate uptake system. The crystal structure of SsuA bound to MOPS, MES and HEPES, which is herein described for the first time, provides evidence for the importance of a conserved dipole in sulphate group coordination, identifies specific amino acids interacting with the sulphate group and shows the presence of a rather large binding pocket that explains the rather wide range of molecules recognised by the protein. Isolation of an isogenic ssuA-knockout derivative of the X. citri 306 strain showed that disruption of alkanesulphonate uptake affects both xanthan gum production and generation of canker lesions in sweet orange leaves. Conclusions/Significance The present study unravels unique structural and functional features of the X. citri SsuA protein and provides the first experimental evidence that an ABC uptake system affects the virulence of this phytopathogen. PMID:24282519

  5. Structural and physiological analyses of the alkanesulphonate-binding protein (SsuA of the citrus pathogen Xanthomonas citri.

    Directory of Open Access Journals (Sweden)

    Fabiano Tófoli de Araújo

    Full Text Available BACKGROUND: The uptake of sulphur-containing compounds plays a pivotal role in the physiology of bacteria that live in aerobic soils where organosulfur compounds such as sulphonates and sulphate esters represent more than 95% of the available sulphur. Until now, no information has been available on the uptake of sulphonates by bacterial plant pathogens, particularly those of the Xanthomonas genus, which encompasses several pathogenic species. In the present study, we characterised the alkanesulphonate uptake system (Ssu of Xanthomonas axonopodis pv. citri 306 strain (X. citri, the etiological agent of citrus canker. METHODOLOGY/PRINCIPAL FINDINGS: A single operon-like gene cluster (ssuEDACB that encodes both the sulphur uptake system and enzymes involved in desulphurisation was detected in the genomes of X. citri and of the closely related species. We characterised X. citri SsuA protein, a periplasmic alkanesulphonate-binding protein that, together with SsuC and SsuB, defines the alkanesulphonate uptake system. The crystal structure of SsuA bound to MOPS, MES and HEPES, which is herein described for the first time, provides evidence for the importance of a conserved dipole in sulphate group coordination, identifies specific amino acids interacting with the sulphate group and shows the presence of a rather large binding pocket that explains the rather wide range of molecules recognised by the protein. Isolation of an isogenic ssuA-knockout derivative of the X. citri 306 strain showed that disruption of alkanesulphonate uptake affects both xanthan gum production and generation of canker lesions in sweet orange leaves. CONCLUSIONS/SIGNIFICANCE: The present study unravels unique structural and functional features of the X. citri SsuA protein and provides the first experimental evidence that an ABC uptake system affects the virulence of this phytopathogen.

  6. The cys regulon of Xanthomonas citri

    Energy Technology Data Exchange (ETDEWEB)

    Moutran, A.; Balan, A. [Laboratorio Nacional de Biociencias - LNBIO, Campinas, SP (Brazil)

    2012-07-01

    Full text: In Escherichia coli, genes involved in metabolic pathway of sulfate and sulfonate compounds are clustered in a cys regulon, which includes three ABC transport system (operons: sbpcysWUA; ssuABC and tauABC), thirteen genes involved in the sulfur reduction (ssuDE; tauD and cysDNCHIJGK) and two regulatory proteins that belong to LysR transcription family: CysB and Cbl. Notably, a search and comparative analysis of these genes in the genomes of the citrus pathogen Xanthomonas citri and other phylogenetically related Xanthomonas species revealed the presence of genes involved with alkanesulfonate, sulfate ester and taurine, only in X. citri, suggesting that proteins from this regulon might be associated with pathogenicity in citrus. Using the molecular modeling associated with a system biology view, we modeled all the protein structures of the X. citri cys regulon as well as characterized the important residues forming the putative active sites. Comparison with orthologs from different microorganisms was made in order to get a phylogenetic relationships. We showed that proteins that are responsible for the affinity and specificity of the alkanesulfonate, sulfate and taurine transport systems conserved the residues involved in the sulfate coordination but are organized in different branches in evolution. Inside these phylogenetic branches, proteins involved in the sulfate transporter are highly conserved when compared to the others. Moreover, we identified that the taurine-binding protein (TauA) of the X. citri belongs to a different evolutionary branch from that one that described for E. coli. These differences were also noticed for components of the tau operon, including a putative new regulator. The function and mechanism of action of each protein is discussed in order to bring light for the sulfur assimilation processes and their importance for X. citri physiology. (author)

  7. Using mass spectrometry for identification of ABC transporters from Xanthomonas citri and mutants expressed in different growth conditions

    Energy Technology Data Exchange (ETDEWEB)

    Faria, J.N.; Balan, A. [Laboratorio Nacional de Biociencias - LNBIO, Campinas, SP (Brazil); Paes Leme, A.F. [Laboratorio Nacional de Luz Sincrotron (LNLS), Campinas, SP (Brazil)

    2012-07-01

    Full text: Xanthomonas citri is a phytopathogenic bacterium that infects citrus plants causing significant losses for the economy. In our group, we have focused on the identification and characterization of ABC transport proteins of this bacterium, in order to determinate their function for growth in vitro and in vivo, during infection. ABC transporters represent one of the largest families of proteins, which transport since small molecules as ions up to oligopeptides and sugars. In prokaryotic cells many works have reported the ABC transport function in pathogenesis, resistance, biofilm formation, infectivity and DNA repair, but until our knowledge, there is no data related to these transporters and X. citri. So, In order to determinate which transporters are expressed in X. citri, we started a proteomic analysis based on mono and bi-dimensional gels associated to mass spectrometry analyses. After growing X. citri and two different mutants deleted for ssuA and nitA genes in LB and minimum media, cellular extracts were obtained and used for preparation of mono and bi-dimensional gels. Seven bands covering the expected mass of ABC transporter components (20 kDa to 50 kDa) in SDS-PAGE were cut off the gel, treated with trypsin and submitted to the MS for protein identification. The results of 2D gels were good enough and will serve as a standard for development of similar experiments in large scale. (author)

  8. Characterization of a variant of Xanthomonas citri subsp. citri that triggers a host-specific defense response.

    Science.gov (United States)

    Chiesa, María A; Siciliano, María F; Ornella, Leonardo; Roeschlin, Roxana A; Favaro, María A; Delgado, Natalia Pino; Sendín, Lorena N; Orce, Ingrid G; Ploper, L Daniel; Vojnov, Adrian A; Vacas, José Gadea; Filippone, María P; Castagnaro, Atilio P; Marano, María R

    2013-06-01

    Citrus is an economically important fruit crop that is severely afflicted by Asiatic citrus bacterial canker (CBC), a disease caused by the phytopathogen Xanthomonas citri subsp. citri (X. citri). To gain insight into the molecular epidemiology of CBC, 42 Xanthomonas isolates were collected from a range of Citrus spp. across 17 different orchards in Tucumán, Argentina and subjected to molecular, biochemical, and pathogenicity tests. Analysis of genome-specific X. citri markers and DNA polymorphisms based on repetitive elements-based polymerase chain reaction showed that all 42 isolates belonged to X. citri. Interestingly, pathogenicity tests showed that one isolate, which shares >90% genetic similarity to the reference strain X. citri T, has host range specificity. This new variant of X. citri subsp. citri, named X. citri A(T), which is deficient in xanthan production, induces an atypical, noncankerous chlorotic phenotype in Citrus limon and C. paradisi and weak cankerous lesions in C. aurantifolia and C. clementina leaves. In C. limon, suppression of canker development is concomitant with an oxidative burst; xanthan is not implicated in the phenotype induced by this interaction, suggesting that other bacterial factors would be involved in triggering the defense response.

  9. Temporal response and attraction of Diaphorina citri to visual stimuli

    Science.gov (United States)

    As the vector of the global disease of citrus greening or huanglongbing, Asian citrus pysllids, Diaphorina citri Kuwayama (Hemiptera; Liviidae) are the greatest threat to the worldwide citrus industry. Critical to management of D. citri and huanglongbing, is optimization of surveillance methodologie...

  10. Presencia de Diaphorina citri (Hemiptera: Psyllidae en el Noroeste Argentino (NOA Record of Diaphorina citri (Hemiptera: Psyllidae in North West Argentina

    Directory of Open Access Journals (Sweden)

    Lucrecia Augier

    2006-12-01

    Full Text Available Se amplía la distribución de Diaphorina citri Kuwayama (Hemiptera: Psyllidae para el Noroeste Argentino.The distribution of Diaphorina citri Kuwayama (Hemiptera: Psyllidae is expanded to North West Argentina.

  11. Autonomous cascaded PV system

    OpenAIRE

    2011-01-01

    This paper proposes multi-level PV system; three PV generators each coupled to a buck cell. Each PV-generator-buckconverter channel is controlled such that maximum power is captured independently under different irradiation and temperature levels. The system operation under normal/abnormal conditions is investigated by thoroughly mathematical and simulation work. Peer Reviewed

  12. Selection of Small Synthetic Antimicrobial Peptides Inhibiting Xanthomonas citri subsp. citri Causing Citrus Canker

    Science.gov (United States)

    Choi, Jeahyuk; Park, Euiho; Lee, Se-Weon; Hyun, Jae-Wook; Baek, Kwang-Hyun

    2017-01-01

    Citrus canker disease decreases the fruit quality and yield significantly, furthermore, emerging of streptomycin-resistant pathogens threatens the citrus industry seriously because of a lack of proper control agents. Small synthetic antimicrobial peptides (AMPs) could be a promising alternative. Fourteen hexapeptides were selected by using positional scanning of synthetic peptide combinatorial libraries. Each hexapeptide showed different antimicrobial spectrum against Bacillus, Pseudomonas, Xanthomonas, and Candida species. Intriguingly, BHC10 showed bactericidal activity exclusively on Xanthomonas citri subsp. citri (Xcc), while BHC7 was none-active exclusively against two Pseudomonas spp. at concentration of 100 μg/ml suggesting potential selectivity constrained in hexapeptide frame. Three hexapeptides, BHC02, 06 and 11, showed bactericidal activities against various Xcc strains at concentration of 10 μg/ml. When they were co-infiltrated with pathogens into citrus leaves the disease progress was suppressed significantly. Further study would be needed to confirm the actual disease control capacity of the selected hexapeptides. PMID:28167892

  13. Pemphigus: Epidemiology and Pathogenesis

    Directory of Open Access Journals (Sweden)

    Yelda Karıncaoğlu

    2008-08-01

    Full Text Available Pemphigus, a group of bullous diseases affecting the oral mucosa and the skin, is caused by antibody-mediated autoimmune reaction to desmogleins (Dsg, desmosomal transmembrane glycoproteins, leading to acantholysis. Pemphigus has a worldwide distribution but the incidence in patients of Jewish origin is higher. The disease has a peak incidence of occurrence between the 4th and 6th decades. While various environmental factors have been implicated as triggering agents, HLA association is probably the most important predisposing factor. Pemphigus, is caused by antibody-mediated autoimmune reaction to desmosomal cadherins, Dsg1, and Dsg3. Recent molecular studies have shown that acantholysis can occur also in the presence of antibodies against 9a nicotinic acetylcholine receptor. Pemphigus is currently divided into three distinct varieties, i.e., pemphigus vulgaris (PV, pemphigus foliaceus (PF and other variants of pemphigus, depending on clinical features, the level of separation in the epidermis, and immunologic characteristics of auto-antigens. Blistering pathogenesis differ for each of the types of pemphigus. PV is characterized by IgG autoantibodies against Dsg 3, whereas the target of PF is Dsg1, although about 50% of PV patients also have Dsg1 autoantibodies. Lesion distribution is related to the location of the antigen (Dgs 3 and/or Dgs 1 in the epithelium and specific autoantibody production. This article reviews the epidemiology and pathogenesis of pemphigus.

  14. Fire resistant PV shingle assembly

    Science.gov (United States)

    Lenox, Carl J.

    2012-10-02

    A fire resistant PV shingle assembly includes a PV assembly, including PV body, a fire shield and a connection member connecting the fire shield below the PV body, and a support and inter-engagement assembly. The support and inter-engagement assembly is mounted to the PV assembly and comprises a vertical support element, supporting the PV assembly above a support surface, an upper interlock element, positioned towards the upper PV edge, and a lower interlock element, positioned towards the lower PV edge. The upper interlock element of one PV shingle assembly is inter-engageable with the lower interlock element of an adjacent PV shingle assembly. In some embodiments the PV shingle assembly may comprise a ventilation path below the PV body. The PV body may be slidably mounted to the connection member to facilitate removal of the PV body.

  15. The dual nature of trehalose in citrus canker disease: a virulence factor for Xanthomonas citri subsp. citri and a trigger for plant defence responses.

    Science.gov (United States)

    Piazza, Ainelén; Zimaro, Tamara; Garavaglia, Betiana S; Ficarra, Florencia A; Thomas, Ludivine; Marondedze, Claudius; Feil, Regina; Lunn, John E; Gehring, Chris; Ottado, Jorgelina; Gottig, Natalia

    2015-05-01

    Xanthomonas citri subsp. citri (Xcc) is a bacterial pathogen that causes citrus canker in susceptible Citrus spp. The Xcc genome contains genes encoding enzymes from three separate pathways of trehalose biosynthesis. Expression of genes encoding trehalose-6-phosphate synthase (otsA) and trehalose phosphatase (otsB) was highly induced during canker development, suggesting that the two-step pathway of trehalose biosynthesis via trehalose-6-phosphate has a function in pathogenesis. This pathway was eliminated from the bacterium by deletion of the otsA gene. The resulting XccΔotsA mutant produced less trehalose than the wild-type strain, was less resistant to salt and oxidative stresses, and was less able to colonize plant tissues. Gene expression and proteomic analyses of infected leaves showed that infection with XccΔotsA triggered only weak defence responses in the plant compared with infection with Xcc, and had less impact on the host plant's metabolism than the wild-type strain. These results suggested that trehalose of bacterial origin, synthesized via the otsA-otsB pathway, in Xcc, plays a role in modifying the host plant's metabolism to its own advantage but is also perceived by the plant as a sign of pathogen attack. Thus, trehalose biosynthesis has both positive and negative consequences for Xcc. On the one hand, it enables this bacterial pathogen to survive in the inhospitable environment of the leaf surface before infection and exploit the host plant's resources after infection, but on the other hand, it is a tell-tale sign of the pathogen's presence that triggers the plant to defend itself against infection. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  16. The dual nature of trehalose in citrus canker disease: a virulence factor for Xanthomonas citri subsp. citri and a trigger for plant defence responses

    KAUST Repository

    Piazza, A.

    2015-03-14

    Xanthomonas citri subsp. citri (Xcc) is a bacterial pathogen that causes citrus canker in susceptible Citrus spp. The Xcc genome contains genes encoding enzymes from three separate pathways of trehalose biosynthesis. Expression of genes encoding trehalose-6-phosphate synthase (otsA) and trehalose phosphatase (otsB) was highly induced during canker development, suggesting that the two-step pathway of trehalose biosynthesis via trehalose-6-phosphate has a function in pathogenesis. This pathway was eliminated from the bacterium by deletion of the otsA gene. The resulting XccΔotsA mutant produced less trehalose than the wild-type strain, was less resistant to salt and oxidative stresses, and was less able to colonize plant tissues. Gene expression and proteomic analyses of infected leaves showed that infection with XccΔotsA triggered only weak defence responses in the plant compared with infection with Xcc, and had less impact on the host plant\\'s metabolism than the wild-type strain. These results suggested that trehalose of bacterial origin, synthesized via the otsA-otsB pathway, in Xcc, plays a role in modifying the host plant\\'s metabolism to its own advantage but is also perceived by the plant as a sign of pathogen attack. Thus, trehalose biosynthesis has both positive and negative consequences for Xcc. On the one hand, it enables this bacterial pathogen to survive in the inhospitable environment of the leaf surface before infection and exploit the host plant\\'s resources after infection, but on the other hand, it is a tell-tale sign of the pathogen\\'s presence that triggers the plant to defend itself against infection. © The Author 2015. Published by Oxford University Press on behalf of the Society for Experimental Biology.

  17. Coccidoxenoides perminutus parasitizing Planococcus citri on vine in Brazil

    Directory of Open Access Journals (Sweden)

    Maria Herlândia de Araújo Fernandes

    2016-07-01

    Full Text Available ABSTRACT: From those of the mealybug family, the citrus mealybug, Planococcus citriRisso, 1813 (Hemiptera: Pseudococcidae is frequently held responsible for various diseases occurring in vineyards. This is a first time report in Brazil, on the occurrence of a parasitoid controlling P. citri. In our search for the natural enemies of P. citri, bunches of grapes with the vine were collected every week for one month, in those regions where table grapes were produced, like Petrolina, Pernambuco, Brazil. In these samples, among the natural pest infestations Coccidoxenoides perminutusGirault, 1915 (Hymenoptera: Encyrtidae was the only natural enemy species reported. In this research, we attempted to study the potential of parasitism as well as the strategies that this natural agent uses in pest control.

  18. Ultraviolet irradiation mutagenesis and recombination in spiroplasma citri

    Energy Technology Data Exchange (ETDEWEB)

    Labarere, J.; Barroso, G. (Bordeaux-2 Univ., 33 (France))

    1984-09-01

    A method for obtaining and screening uv-induced mutants from Spiroplasma citri is described. Lethality response curves showed that S. citri is more sensitive to uv irradiation than are other microorganisms. The presence of a shoulder in the lethality response curve showed the existence of systems able to repair uv-induced DNA damages. Toxic-resistant mutants have been obtained. A uv fluence equal to 10 J/m/sup 2/ multiplied by 2.5x10/sup 3/ gave the spontaneous mutation frequency. Arsenic acid- and xylitol-resistant mutants were used to investigate transfer of genetic information in S. citri. After 90 min of incubation, the recombination frequency was 5x10/sup -5/.

  19. treA Codifies for a Trehalase with Involvement in Xanthomonas citri subsp. citri Pathogenicity

    Science.gov (United States)

    Alexandrino, André Vessoni; Goto, Leandro Seiji; Novo-Mansur, Maria Teresa Marques

    2016-01-01

    Citrus canker, caused by the bacterium Xanthomonas citri subsp. citri (Xcc), is a severe disease of citrus. Xcc presents broad spectrum of citrus hosts including economically important species whereas X. fuscans subsp. aurantifolii–type C (XauC) causes a milder disease and only infects Citrus aurantifolia. Trehalase catalyzes hydrolysis of the disaccharide trehalose, a sugar that has been reported to be related to Xcc pathogenicity. We expressed the recombinant gene product and assessed Xcc trehalase structural and kinetics data. The recombinant protein presented 42.7% of secondary structures in α-helix and 13% in β-sheets, no quaternary structure in solution, and Michaelis-Menten constant (KM) of 0.077 mM and Vmax 55.308 μMol glucose.min-1.mg protein-1 for trehalose. A Xcc mutant strain (XccΔtreA) was produced by gene deletion from Xcc genome. Enzymatic activity of trehalase was determined in Xcc, XauC and XccΔtreA cellular lysates, showing the highest values for XauC in in vitro infective condition and no activity for XccΔtreA. Finally, leaves of Citrus aurantifolia infected with XccΔtreA showed much more drenching and necrosis than those infected by wild type Xcc. We concluded that trehalase contributes to alleviate bacterial virulence and that inability for trehalose hydrolysis may promote higher Xcc infectivity. PMID:27611974

  20. treA Codifies for a Trehalase with Involvement in Xanthomonas citri subsp. citri Pathogenicity.

    Science.gov (United States)

    Alexandrino, André Vessoni; Goto, Leandro Seiji; Novo-Mansur, Maria Teresa Marques

    2016-01-01

    Citrus canker, caused by the bacterium Xanthomonas citri subsp. citri (Xcc), is a severe disease of citrus. Xcc presents broad spectrum of citrus hosts including economically important species whereas X. fuscans subsp. aurantifolii-type C (XauC) causes a milder disease and only infects Citrus aurantifolia. Trehalase catalyzes hydrolysis of the disaccharide trehalose, a sugar that has been reported to be related to Xcc pathogenicity. We expressed the recombinant gene product and assessed Xcc trehalase structural and kinetics data. The recombinant protein presented 42.7% of secondary structures in α-helix and 13% in β-sheets, no quaternary structure in solution, and Michaelis-Menten constant (KM) of 0.077 mM and Vmax 55.308 μMol glucose.min-1.mg protein-1 for trehalose. A Xcc mutant strain (XccΔtreA) was produced by gene deletion from Xcc genome. Enzymatic activity of trehalase was determined in Xcc, XauC and XccΔtreA cellular lysates, showing the highest values for XauC in in vitro infective condition and no activity for XccΔtreA. Finally, leaves of Citrus aurantifolia infected with XccΔtreA showed much more drenching and necrosis than those infected by wild type Xcc. We concluded that trehalase contributes to alleviate bacterial virulence and that inability for trehalose hydrolysis may promote higher Xcc infectivity.

  1. A protein expression system for tandem affinity purification in Xanthomonas citri subsp. citri

    Directory of Open Access Journals (Sweden)

    Giordanni C. Dantas

    2016-06-01

    Full Text Available Abstract Citrus canker, caused by the Gram-negative bacterium Xanthomonas citri subsp. citri (Xac, is one of the most devastating diseases to affect citrus crops. There is no treatment for citrus canker; effective control against the spread of Xac is usually achieved by the elimination of affected plants along with that of asymptomatic neighbors. An in depth understanding of the pathogen is the keystone for understanding of the disease; to this effect we are committed to the development of strategies to ease the study of Xac. Genome sequencing and annotation of Xac revealed that ∼37% of the genome is composed of hypothetical ORFs. To start a systematic characterization of novel factors encoded by Xac, we constructed integrative-vectors for protein expression specific to this bacterium. The vectors allow for the production of TAP-tagged proteins in Xac under the regulation of the xylose promoter. In this study, we show that a TAP-expression vector, integrated into the amy locus of Xac, does not compromise its virulence. Furthermore, our results also demonstrate that the polypeptide TAP can be overproduced in Xac and purified from the soluble phase of cell extracts. Our results substantiate the use of our vectors for protein expression in Xac thus contributing a novel tool for the characterization of proteins and protein complexes generated by this bacterium in vivo.

  2. Bioactive Organocopper Compound from Pseudomonas aeruginosa Inhibits the Growth of Xanthomonas citri subsp. citri

    Science.gov (United States)

    de Oliveira, Admilton G.; Spago, Flavia R.; Simionato, Ane S.; Navarro, Miguel O. P.; da Silva, Caroline S.; Barazetti, André R.; Cely, Martha V. T.; Tischer, Cesar A.; San Martin, Juca A. B.; de Jesus Andrade, Célia G. T.; Novello, Cláudio R.; Mello, João C. P.; Andrade, Galdino

    2016-01-01

    Citrus canker is a very destructive disease of citrus species. The challenge is to find new compounds that show strong antibiotic activity and low toxicity to plants and the environment. The objectives of the present study were (1) to extract, purify and evaluate the secondary metabolites with antibiotic activity produced by Pseudomonas aeruginosa LV strain in vitro against Xanthomonas citri subsp. citri (strain 306), (2) to determine the potential of semi-purified secondary metabolites in foliar application to control citrus canker under greenhouse conditions, and (3) to identify antibiotic activity in orange leaf mesophyll infected with strain 306, by electron microscopy. Two pure bioactive compounds were isolated, an organocopper antibiotic compound (OAC) and phenazine-1-carboxamide. Phenazine-1-carboxamide did not show any antibiotic activity under the experimental conditions used in this study. The OAC showed a high level of antibiotic activity with a minimum inhibitory concentration of 0.12 μg mL-1. In greenhouse tests for control of citrus canker in orange trees, the semi-purified fraction F3d reduced lesion formation by about 97%. The concentration used was 500 times lower than that for the recommended commercial copper-based product. Electron microscopy showed that F3d altered the exopolysaccharide matrix and caused cell lysis of the pathogen inside the citrus canker lesions. These results suggest that secondary metabolites produced by inducing P. aeruginosa LV strain have a high potential to be used as a bioproduct to control citrus canker. PMID:26903992

  3. In Vitro and In Vivo Antibacterial Activity of Some Organic and Inorganic Salts Against Asiatic Citrus Canker Agent Xanthomonas Citri Subsp. Citri

    Directory of Open Access Journals (Sweden)

    Vahideh Hasabi

    2014-06-01

    Full Text Available Asiatic citrus canker caused by Xanthomonas citri subsp. citri is becoming a disease of high economic impact, affecting all types of important citrus crops. In this study, the potential antibacterial activity of ten organic and inorganic salts on X. citri subsp. citri and on citrus canker disease development was evaluated. Among the salt compounds, copper, iron and zinc inorganic salts particularly zinc (with the highest diameter of inhibition, the lowest MIC and MBC values and the highest bacterial growth inhibitory effect had direct antibacterial activity and strongly reduced the development of canker disease and bacterial population of lime plants.

  4. PV power plants

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2012-07-01

    Within the international seminar of the Ostbayerisches Technologie-Transfer-Institut e.V. (OTTI) at 11th June, 2012 in Munich (Federal Republic of Germany), the following lectures were held: (1) Technical due diligence (Dietmar Obst); (2) Certification / rating system for large PV plants (Robert Pfatischer); (3) O and M requirements (Lars Rulf); (4) IR photography for large scale systems (Bernhard Weinreich); (5) New market models for PV systems - direct marketing and sales of PV electricity (Martin Schneider); (6) Needs and benefits for plant certification for grid connection and operation (Christoph Luetke-Lengerich); (7) Lare volume module testing / Screening in the field and workshop (Semir Merzoug); (8) Dismantling costs of large scale PV plants (Siegfried Schimpf).

  5. Grid integrated distributed PV (GridPV).

    Energy Technology Data Exchange (ETDEWEB)

    Reno, Matthew J.; Coogan, Kyle

    2013-08-01

    This manual provides the documentation of the MATLAB toolbox of functions for using OpenDSS to simulate the impact of solar energy on the distribution system. The majority of the functions are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in the OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feeder on satellite images with GPS coordinates. Finally, example simulations functions are included to show potential uses of the toolbox functions. Each function in the toolbox is documented with the function use syntax, full description, function input list, function output list, example use, and example output.

  6. New Protein-Protein Interactions Identified for the Regulatory and Structural Components and Substrates of the Type III Secretion System of the Phytopathogen Xanthomonas axonopodis Pathovar citri

    Science.gov (United States)

    Alegria, Marcos C.; Docena, Cassia; Khater, Leticia; Ramos, Carlos H. I.; da Silva, Ana C. R.; Farah, Chuck S.

    2004-01-01

    We have initiated a project to identify protein-protein interactions involved in the pathogenicity of the bacterial plant pathogen Xanthomonas axonopodis pv. citri. Using a yeast two-hybrid system based on Gal4 DNA-binding and activation domains, we have focused on identifying interactions involving subunits, regulators, and substrates of the type III secretion system coded by the hrp (for hypersensitive response and pathogenicity), hrc (for hrp conserved), and hpa (for hrp associated) genes. We have identified several previously uncharacterized interactions involving (i) HrpG, a two-component system response regulator responsible for the expression of X. axonopodis pv. citri hrp operons, and XAC0095, a previously uncharacterized protein encountered only in Xanthomonas spp.; (ii) HpaA, a protein secreted by the type III secretion system, HpaB, and the C-terminal domain of HrcV; (iii) HrpB1, HrpD6, and HrpW; and (iv) HrpB2 and HrcU. Homotropic interactions were also identified for the ATPase HrcN. These newly identified protein-protein interactions increase our understanding of the functional integration of phytopathogen-specific type III secretion system components and suggest new hypotheses regarding the molecular mechanisms underlying Xanthomonas pathogenicity. PMID:15342589

  7. The complete mitochondrial genome sequence of Diaphorina citri (Hemiptera: Psyllidae)

    Science.gov (United States)

    The first complete mitochondrial genome (mitogenome) sequence of Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae), from Guangzhou, China is presented. The circular mitogenome is 14,996 bp in length with an A+T content of 74.5%, and contains 13 protein-coding genes (PCGs), 22 tRNA genes ...

  8. Vibrational communication between the sexes in Diaphorina citri (Hemiptera: Psyllidae)

    Science.gov (United States)

    We examined the substrate-borne vibrational signals used in communication between the sexes in Diaphorina citri Kuwayama (Hemiptera: Psyllidae), a vector of huanglongbing (an economically devastating disease of citrus), in an anechoic chamber and an olfactometer. Males and females both primarily pro...

  9. The Effect of Citrus Essential Oils and Their Constituents on Growth of Xanthomonas citri subsp. citri.

    Science.gov (United States)

    Mirzaei-Najafgholi, Hossein; Tarighi, Saeed; Golmohammadi, Morteza; Taheri, Parissa

    2017-04-14

    Citrus bacterial canker (CBC) caused by Xanthomonas citri subsp. citri (Xcc), is the most devastating of the citrus diseases worldwide. During our study, we found that Essential oils (EOs) of some citrus cultivars are effective on Xcc. Therefore, it prompted us to determine the plant metabolites responsible for the antibacterial properties. We obtained EOs from some locally cultivated citrus by using a Clevenger apparatus and their major constituents were identified by gas chromatography/mass spectrometry (GC-MS). The effect of Citrus aurantium, C. aurantifolia, Fortunella sp. EOs and their major constituents were evaluated against Xcc-KVXCC1 using a disk diffusion assay. Minimal inhibitory and bactericidal concentration of the EOs and their constituents were determined using the broth microdilution method. C. aurantium, C. aurantifolia Eos, and their major constituents including citral, linalool, citronellal, geraniol, α-terpineol, and linalyl acetate indicated antibacterial effects against Xcc. The C. aurantifolia EO and citral showed the highest antibacterial activity among the tested EOs and constituents with inhibition zones of 15 ± 0.33 mm and 16.67 ± 0.88 mm, respectively. Synergistic effects of the constituents were observed between α-terpineol-citral, citral-citronellal, citral-geraniol, and citronellal-geraniol by using a microdilution checkerboard assay. Transmission electron microscopy revealed that exposure of Xcc cells to citral caused cell wall damage and altered cytoplasmic density. We introduced C. aurantifolia and C. aurantium EOs, and their constituents citral, α-terpineol, citronellal, geraniol, and linalool as possible control agents for CBC.

  10. Proteome of the phytopathogen Xanthomonas citri subsp. citri: a global expression profile

    Directory of Open Access Journals (Sweden)

    Ferro Jesus A

    2010-11-01

    Full Text Available Abstract Background Citrus canker is a disease caused by Xantomonas citri subsp.citri (Xac, and has emerged as one of the major threats to the worldwide citrus crop because it affects all commercial citrus varieties, decreases the production and quality of the fruits and can spread rapidly in citrus growing areas. In this work, the first proteome of Xac was analyzed using two methodologies, two-dimensional liquid chromatography (2D LC and tandem mass spectrometry (MS/MS. Results In order to gain insight into the metabolism of Xac, cells were grown on two different media (NB - Nutrient Broth and TSE - Tryptone Sucrose broth enriched with glutamic acid, and proteins were proteolyzed with trypsin and examined by 2D LC-MS/MS. Approximately 39% of all predicted proteins by annotation of Xac were identified with their component peptides unambiguously assigned to tandem mass spectra. The proteins, about 1,100, were distributed in all annotated functional categories. Conclusions This is the first proteomic reference map for the most aggressive strain of Xanthomonas pathogen of all orange varieties. The compilation of metabolic pathways involved with bacterial growth showed that Xac expresses a complete central and intermediary metabolism, replication, transcription and translation machineries and regulation factors, distinct membrane transporters (ABC, MFS and pumps and receptors (MCP, TonB dependent and metabolites acquisition, two-component systems (sensor and regulatory components and response regulators. These data corroborate the growth curve in vitro and are the first reports indicating that many of these genome annotated genes are translated into operative in Xac. This proteomic analysis also provided information regarding the influence of culture medium on growth and protein expression of Xac.

  11. Non-host defense response in a novel Arabidopsis-Xanthomonas citri subsp. citri pathosystem.

    Directory of Open Access Journals (Sweden)

    Chuanfu An

    Full Text Available Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc, is one of the most destructive diseases of citrus. Progress of breeding citrus canker-resistant varieties is modest due to limited resistant germplasm resources and lack of candidate genes for genetic manipulation. The objective of this study is to establish a novel heterologous pathosystem between Xcc and the well-established model plant Arabidopsis thaliana for defense mechanism dissection and resistance gene identification. Our results indicate that Xcc bacteria neither grow nor decline in Arabidopsis, but induce multiple defense responses including callose deposition, reactive oxygen species and salicylic aicd (SA production, and defense gene expression, indicating that Xcc activates non-host resistance in Arabidopsis. Moreover, Xcc-induced defense gene expression is suppressed or attenuated in several well-characterized SA signaling mutants including eds1, pad4, eds5, sid2, and npr1. Interestingly, resistance to Xcc is compromised only in eds1, pad4, and eds5, but not in sid2 and npr1. However, combining sid2 and npr1 in the sid2npr1 double mutant compromises resistance to Xcc, suggesting genetic interactions likely exist between SID2 and NPR1 in the non-host resistance against Xcc in Arabidopsis. These results demonstrate that the SA signaling pathway plays a critical role in regulating non-host defense against Xcc in Arabidopsis and suggest that the SA signaling pathway genes may hold great potential for breeding citrus canker-resistant varieties through modern gene transfer technology.

  12. Complete Genome Sequence of the Largest Known Flavi-Like Virus, Diaphorina citri flavi-like virus, a Novel Virus of the Asian Citrus Psyllid, Diaphorina citri.

    Science.gov (United States)

    Matsumura, Emilyn E; Nerva, Luca; Nigg, Jared C; Falk, Bryce W; Nouri, Shahideh

    2016-09-08

    A novel flavi-like virus tentatively named Diaphorina citri flavi-like virus (DcFLV) was identified in field populations of Diaphorina citri through small RNA and transcriptome sequencing followed by reverse transcription (RT)-PCR. We report here the complete nucleotide sequence and genome organization of DcFLV, the largest flavi-like virus identified to date.

  13. Complete Genome Sequence of the Largest Known Flavi-Like Virus, Diaphorina citri flavi-like virus, a Novel Virus of the Asian Citrus Psyllid, Diaphorina citri

    Science.gov (United States)

    Matsumura, Emilyn E.; Nerva, Luca; Nigg, Jared C.; Falk, Bryce W.

    2016-01-01

    A novel flavi-like virus tentatively named Diaphorina citri flavi-like virus (DcFLV) was identified in field populations of Diaphorina citri through small RNA and transcriptome sequencing followed by reverse transcription (RT)-PCR. We report here the complete nucleotide sequence and genome organization of DcFLV, the largest flavi-like virus identified to date. PMID:27609921

  14. PV-WEB: internet-based PV information tool

    Energy Technology Data Exchange (ETDEWEB)

    Cowley, P.

    2003-07-01

    This report gives details of a project to create a web-based information system on photovoltaic (PV) systems for the British PV Association (PV-UK) for use by decision makers in government, the utilities, and the housing and construction sectors. The project, which aims to provide an easily accessible tool for UK companies, promote PV technology, increase competitiveness, and identify market opportunities, is described. The design of the web site and its implementation and the evolution are discussed, along with the maintenance of the site by PV-UK and the opportunities offered to PV-UK Members.

  15. The small and large subunits of carbamoyl-phosphate synthase exhibit diverse contributions to pathogenicity in Xanthomonas citri subsp. citri

    Institute of Scientific and Technical Information of China (English)

    Guo Jing; SonG Xue; Zou Li-fang; Zou Hua-song; CHen Gong-you

    2015-01-01

    Carbamoyl-phosphate synthase plays a vital role in the carbon and nitrogen metabolism cycles. In Xanthomonas citri subsp. citri, carA and carB encode the smal and large subunits of carbamoyl-phosphate synthase, respectively. The deletion mutation of the coding regions revealed that carA did not affect any of the phenotypes, while carB played multiple roles in pathogenicity. The deletion of carB rendered the loss of pathogenicity in host plants and the ability to induce a hyper-sensitive reaction in the non-hosts. Quantitative reverse transcription-PCR assays indicated that 11 hrp genes coding the type III secretion system were suppressed when interacting with citrus plants. The mutation in carB also affected bacterial utilization of several carbon and nitrogen resources in minimal medium MMX and extracel ular enzyme activities. These data demonstrated that only the large subunit of carbamoyl-phosphate synthase was essential for canker development by X. citri subsp. citri.

  16. PV power forecast using a nonparametric PV model

    OpenAIRE

    Almeida, Marcelo Pinho; Perpiñan Lamigueiro, Oscar; Narvarte Fernández, Luis

    2015-01-01

    Forecasting the AC power output of a PV plant accurately is important both for plant owners and electric system operators. Two main categories of PV modeling are available: the parametric and the nonparametric. In this paper, a methodology using a nonparametric PV model is proposed, using as inputs several forecasts of meteorological variables from a Numerical Weather Forecast model, and actual AC power measurements of PV plants. The methodology was built upon the R environment and uses Quant...

  17. Repellent Activity of Botanical Oils against Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Kuhns, Emily H; Martini, Xavier; Hoyte, Angel; Stelinski, Lukasz L

    2016-07-14

    The Asian citrus psyllid, Diaphorina citri Kuwayama, is the insect vector of the pathogen causing huanglongbing. We selected three botanical oils to evaluate behavioral activity against D. citri. In laboratory olfactometer assays, fir oil was repellent to D. citri females, while litsea and citronella oils elicited no response from D. citri females. In choice settling experiments, D. citri settled almost completely on control plants rather than on plants treated with fir oil at a 9.5 mg/day release rate. Therefore, we conducted field trials to determine if fir oil reduced D. citri densities in citrus groves. We found no repellency of D. citri from sweet orange resets that were treated with fir oil dispensers releasing 10.4 g/day/tree as compared with control plots. However, we found a two-week decrease in populations of D. citri as compared with controls when the deployment rate of these dispensers was doubled. Our results suggest that treatment of citrus with fir oil may have limited activity as a stand-alone management tool for D. citri and would require integration with other management practices.

  18. Repellent Activity of Botanical Oils against Asian Citrus Psyllid, Diaphorina citri (Hemiptera: Liviidae

    Directory of Open Access Journals (Sweden)

    Emily H. Kuhns

    2016-07-01

    Full Text Available The Asian citrus psyllid, Diaphorina citri Kuwayama, is the insect vector of the pathogen causing huanglongbing. We selected three botanical oils to evaluate behavioral activity against D. citri. In laboratory olfactometer assays, fir oil was repellent to D. citri females, while litsea and citronella oils elicited no response from D. citri females. In choice settling experiments, D. citri settled almost completely on control plants rather than on plants treated with fir oil at a 9.5 mg/day release rate. Therefore, we conducted field trials to determine if fir oil reduced D. citri densities in citrus groves. We found no repellency of D. citri from sweet orange resets that were treated with fir oil dispensers releasing 10.4 g/day/tree as compared with control plots. However, we found a two-week decrease in populations of D. citri as compared with controls when the deployment rate of these dispensers was doubled. Our results suggest that treatment of citrus with fir oil may have limited activity as a stand-alone management tool for D. citri and would require integration with other management practices.

  19. PV investment in Europe

    Energy Technology Data Exchange (ETDEWEB)

    Hueser, Pius [Nova Energy GmbH, (Switzerland)

    2007-06-15

    This presentation is mainly about how the PV market in Europe has been growing, and which elements are going to determine if this market succeed or failed not only in Europe but also in the rest of the world. In the first part of this presentation, it is mentioned how in 2005 the development of some PV technologies triggered the PV market growth without any marketing control. Then, there are explained the aspects that changed such situation out of control, therefore, it emerged the beginning of the consolidation of this market. There are briefly explained those factors that are going to determine if this market succeed or failed in the future. Finally, there are given examples of some the PV investments. [Spanish] Esta presentacion habla principalmente de la manera en como ha crecido el Mercado de sistemas fotovoltaicos en Europa, asi tambien se mencionan los elementos fundamentales que determinaran el exito o fracaso de este mercado, no solamente en Europa sino tambien en el resto del mundo, en un futuro. En la primera parte de esta presentacion, se describe como en el 2005, debido al desarrollo de algunas tecnologias fotovoltaicas se desencadeno el crecimiento desenfrenado del mercado fotovoltaico. Despues, se explican los aspectos que hicieron que dicho crecimiento tomara su curso, teniendo como resultado el inicio de un mercado mas consolidado. Se explican brevemente los factores que determinaran si este mercado encuentra el exito o el fracaso en un futuro. Finalmente, se dan ejemplos de algunas adquisiciones fotovoltaicas.

  20. The gpsX gene encoding a glycosyltransferase is important for polysaccharide production and required for full virulence in Xanthomonas citri subsp. citri

    Directory of Open Access Journals (Sweden)

    Li Jinyun

    2012-03-01

    Full Text Available Abstract Background The Gram-negative bacterium Xanthomonas citri subsp. citri (Xac causes citrus canker, one of the most destructive diseases of citrus worldwide. In our previous work, a transposon mutant of Xac strain 306 with an insertion in the XAC3110 locus was isolated in a screening that aimed at identifying genes related to biofilm formation. The XAC3110 locus was named as bdp24 for biofilm-defective phenotype and the mutant was observed to be affected in extracellular polysaccharide (EPS and lipopolysaccharide (LPS biosynthesis and cell motility. In this study, we further characterized the bdp24 (XAC3110 gene (designated as gpsX using genetic complementation assays and expanded the knowledge about the function of the gpsX gene in Xac pathogenesis by investigating the roles of gpsX in EPS and LPS production, cell motility, biofilm formation on host leaves, stress tolerance, growth in planta, and host virulence of the citrus canker bacterium. Results The gpsX gene encodes a putative glycosyltransferase, which is highly conserved in the sequenced strains of Xanthomonas. Mutation of gpsX resulted in a significant reduction of the amount of EPS and loss of two LPS bands visualized on sodium dodecylsulphate- polyacrylamide gels. Biofilm assays revealed that the gpsX mutation affected biofilm formation by Xac on abiotic and biotic surfaces. The gpsX mutant showed delayed bacterial growth and caused reduced development of disease symptoms in susceptible citrus leaves. The gpsX mutant was more sensitive than the wild-type strain to various stresses, including the H2O2 oxidative stress. The mutant also showed attenuated ability in cell motility but not in flagellar formation. Quantitative reverse transcription-PCR assays indicated that mutation of gpsX did not affect the expression of virulence genes such as pthA in Xac strain 306. The affected phenotypes of the gpsX mutant could be complemented to wild-type levels by the intact gpsX gene

  1. Unravelling potential virulence factor candidates in Xanthomonas citri. subsp. citri by secretome analysis

    Directory of Open Access Journals (Sweden)

    Rafael M. Ferreira

    2016-02-01

    Full Text Available Citrus canker is a major disease affecting citrus production in Brazil. It’s mainly caused by Xanthomonas citri subsp. citri strain 306 pathotype A (Xac. We analysed the differential expression of proteins secreted by wild type Xac and an asymptomatic mutant for hrpB4 (ΔhrpB4 grown in Nutrient Broth (NB and a medium mimicking growth conditions in the plant (XAM1. This allowed the identification of 55 secreted proteins, of which 37 were secreted by both strains when cultured in XAM1. In this secreted protein repertoire, the following stand out: Virk, Polyphosphate-selective porin, Cellulase, Endoglucanase, Histone-like protein, Ribosomal proteins, five hypothetical proteins expressed only in the wild type strain, Lytic murein transglycosylase, Lipoprotein, Leucyl-tRNA synthetase, Co-chaperonin, Toluene tolerance, C-type cytochrome biogenesis membrane protein, Aminopeptidase and two hypothetical proteins expressed only in the ΔhrpB4 mutant. Furthermore, Peptidoglycan-associated outer membrane protein, Regulator of pathogenicity factor, Outer membrane proteins, Endopolygalacturonase, Chorismate mutase, Peptidyl-prolyl cis-trans isomerase and seven hypothetical proteins were detected in both strains, suggesting that there was no relationship with the secretion mediated by the type III secretory system, which is not functional in the mutant strain. Also worth mentioning is the Elongation factor Tu (EF-Tu, expressed only the wild type strain, and Type IV pilus assembly protein, Flagellin (FliC and Flagellar hook-associated protein, identified in the wild-type strain secretome when grown only in NB. Noteworthy, that FliC, EF-Tu are classically characterized as PAMPs (Pathogen-associated molecular patterns, responsible for a PAMP-triggered immunity response. Therefore, our results highlight proteins potentially involved with the virulence. Overall, we conclude that the use of secretome data is a valuable approach that may bring more knowledge of the

  2. Testing for PV Reliability (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, S.; Bansal, S.

    2014-09-01

    The DOE SUNSHOT workshop is seeking input from the community about PV reliability and how the DOE might address gaps in understanding. This presentation describes the types of testing that are needed for PV reliability and introduces a discussion to identify gaps in our understanding of PV reliability testing.

  3. Firefighter Safety for PV Systems

    DEFF Research Database (Denmark)

    Mathe, Laszlo; Sera, Dezso; Spataru, Sergiu

    2015-01-01

    An important and highly discussed safety issue for photovoltaic (PV) systems is that as long as the PV panels are illuminated, a high voltage is present at the PV string terminals and cables between the string and inverters that is independent of the state of the inverter's dc disconnection switc...

  4. PV potential and potential PV rent in European regions

    DEFF Research Database (Denmark)

    Hansen, Anders Chr.; Thorn, Paul

    2013-01-01

    The paper provides a GIS based model for assessing the potentials of photovoltaic electricity in Europe by NUTS 2 regions. The location specific energy potential per PV-­‐panel area is estimated based on observations of solar irradiation, conversion efficiency, levelised costs and the social value...... of PV-­‐electricity. Combined with the potential density of PV-­‐panel area based on land cover and environental restrictions, the PV energy potential and the potential PV ressource rent is calculated. These calculations enbable the model to estimate the regional patterns at NUTS 2 level...

  5. PV potential and potential PV rent in European regions

    DEFF Research Database (Denmark)

    Hansen, Anders Chr.; Thorn, Paul

    2013-01-01

    The paper provides a GIS based model for assessing the potentials of photovoltaic electricity in Europe by NUTS 2 regions. The location specific energy potential per PV-­‐panel area is estimated based on observations of solar irradiation, conversion efficiency, levelised costs and the social value...... of PV-­‐electricity. Combined with the potential density of PV-­‐panel area based on land cover and environental restrictions, the PV energy potential and the potential PV ressource rent is calculated. These calculations enbable the model to estimate the regional patterns at NUTS 2 level...

  6. Improved real-time PCR diagnosis of citrus stubborn disease by targeting prophage genes of Spiroplasma citri

    Science.gov (United States)

    Spiroplasma citri is a phloem-limited bacterium causing citrus stubborn disease (CSD). Isolation and culturing of S. citri is difficult and time consuming. Current detection methods use polymerase chain reaction (PCR) assays with primers developed from sequences of S. citri house-keeping genes. In c...

  7. Complete Genome Sequence of a Putative Densovirus of the Asian Citrus Psyllid, Diaphorina citri.

    Science.gov (United States)

    Nigg, Jared C; Nouri, Shahideh; Falk, Bryce W

    2016-07-28

    Here, we report the complete genome sequence of a putative densovirus of the Asian citrus psyllid, Diaphorina citri Diaphorina citri densovirus (DcDNV) was originally identified through metagenomics, and here, we obtained the complete nucleotide sequence using PCR-based approaches. Phylogenetic analysis places DcDNV between viruses of the Ambidensovirus and Iteradensovirus genera.

  8. First report of citrus canker caused by Xanthomonas citri in Somalia

    Science.gov (United States)

    Xanthomonas citri, causal agent of citrus canker, has been reported in several countries in Africa, but not Somalia. During 2006 and 2007, hyperplasia-type lesions, often surrounded by a water-soaked margin and yellow halo, typical of citrus canker caused by X. citri, were found on 8-10 year-old gr...

  9. Comparison of Droplet Digital PCR and Quantitative PCR Assays for Quantitative Detection of Xanthomonas citri Subsp. citri.

    Directory of Open Access Journals (Sweden)

    Yun Zhao

    Full Text Available Droplet digital polymerase chain reaction (ddPCR is a novel molecular biology technique providing absolute quantification of target nucleic acids without the need for an external calibrator. Despite its emerging applications in medical diagnosis, there are few reports of its use for the detection of plant pathogens. This work was designed to assess the diagnosis potential of the ddPCR for absolute quantitative detection of Xanthomonas citri subsp. citri, a quarantine plant pathogenic bacterium that causes citrus bacterial canker in susceptible Citrus species. We transferred an established quantitative PCR (qPCR assay for citrus bacterial canker diagnosis directly to the ddPCR format and compared the performance of the two methods. The qPCR assay has a broader dynamic range compared to the ddPCR assay and the ddPCR assay has a significantly higher degree of sensitivity compared to the qPCR assay. The influence of PCR inhibitors can be reduced considerably in the ddPCR assay because the collection of end-point fluorescent signals and the counting of binomial events (positive or negative droplets are associated with a Poisson algorithm. The ddPCR assay also shows lower coefficient of variation compared to the qPCR assay especially in low target concentration. The linear association of the measurements by ddPCR and qPCR assays is strong (Pearson correlation = 0.8633; P<0.001. Receiver operating characteristic analysis indicates the ddPCR methodology is a more robust approach for diagnosis of citrus bacterial canker. In summary, the results demonstrated that the ddPCR assay has the potential for the quantitative detection of X. citri subsp. citri with high precision and accuracy as compared with the results from qPCR assay. Further studies are required to evaluate and validate the value of ddPCR technology in the diagnosis of plant disease and quarantine applications.

  10. Migraine Pathogenesis

    Institute of Scientific and Technical Information of China (English)

    Nabih M. M.D. Ramadan

    2000-01-01

    @@Introduction Various theories of migraine pathogenesis have been developed over the years. To this date, none fully explains all the migraine phenomena. A complete description of each proposed theory is beyond the scope of this chapter. Nonetheless, a brief description of the arguments for and against the leading theories is noteworthy

  11. Complete Genome Sequence of Diaphorina citri-associated C virus, a Novel Putative RNA Virus of the Asian Citrus Psyllid, Diaphorina citri.

    Science.gov (United States)

    Nouri, Shahideh; Salem, Nidà; Falk, Bryce W

    2016-07-21

    We present here the complete nucleotide sequence and genome organization of a novel putative RNA virus identified in field populations of the Asian citrus psyllid, Diaphorina citri, through sequencing of the transcriptome followed by reverse transcription-PCR (RT-PCR). We tentatively named this virus Diaphorina citri-associated C virus (DcACV). DcACV is an unclassified positive-sense RNA virus.

  12. Molecular study on the carAB operon reveals that carB gene is required for swimming and biofilm formation in Xanthomonas citri subsp. citri.

    Science.gov (United States)

    Zhuo, Tao; Rou, Wei; Song, Xue; Guo, Jing; Fan, Xiaojing; Kamau, Gicharu Gibson; Zou, Huasong

    2015-10-23

    The carA and carB genes code the small and large subunits of carbamoyl-phosphate synthase (CPS) that responsible for arginine and pyrimidine production. The purpose of this work was to study the gene organization and expression pattern of carAB operon, and the biological functions of carA and carB genes in Xanthomonas citri subsp. citri. RT-PCR method was employed to identify the full length of carAB operon transcript in X. citri subsp. citri. The promoter of carAB operon was predicted and analyzed its activity by fusing a GUS reporter gene. The swimming motility was tested on 0.25% agar NY plates with 1% glucose. Biofilm was measured by cell adhesion to polyvinyl chloride 96-well plate. The results indicated that carAB operon was composed of five gene members carA-orf-carB-greA-rpfE. A single promoter was predicted from the nucleotide sequence upstream of carAB operon, and its sensitivity to glutamic acid, uracil and arginine was confirmed by fusing a GUS reporter gene. Deletion mutagenesis of carB gene resulted in reduced abilities in swimming on soft solid media and in forming biofilm on polystyrene microtiter plates. From these results, we concluded that carAB operon was involved in multiple biological processes in X. citri subsp. citri.

  13. PV water pumping: NEOS Corporation recent PV water pumping activities

    Energy Technology Data Exchange (ETDEWEB)

    Lane, C.

    1995-11-01

    NEOS Corporation has been very active in PV-powered water pumping, particularly with respect to electric utilities. Most of the recent activity has been through the Photovoltaic Services Network (PSN). The PSN is an independent, not-for-profit organization comprised of all types of electric utilities: rural electric coops, public power districts, investor-owned utilities, and power marketing agencies. The PSN`s mission is to work pro-actively to promote utility involvement in PV through education and training. PV information is distributed by the PSN in three primary forms: (1) consultation with PSN technical service representatives: (2) literature generated by the PSN; and (3) literature published by other organizations. The PSN can also provide assistance to members in developing PV customer service programs. The PSN`s product support activities include consolidation of information on existing packaged PV systems and facilitation of the development of new PV product packages that meet utility-defined specifications for cost performance, and reliability. The PSN`s initial product support efforts will be focused on commercially available packaged PV systems for a variety of off-grid applications. In parallel with this effort, if no products exist that meet the PSN`s functional specifications, the PSN will initiate the second phase of product development support process by encouraging the development of new packaged systems. Through these services and product support activities, the PSN anticipates engaging all segments for the PV industry, thus providing benefits to PV systems suppliers as well as local PV service contractors.This paper describes field testing of pv power systems for water pumping.

  14. Sensorless PV Array Diagnostic Method for Residential PV Systems

    DEFF Research Database (Denmark)

    Sera, Dezso; Spataru, Sergiu; Mathe, Laszlo

    2011-01-01

    This work proposes a temperature and irradiance sensorless diagnostic method suitable for small residential PV installations, focusing on detection of partial shadows. The method works by detection of failures in crystalline silicone PV arrays by concomitant monitoring of some of their key parame...

  15. Spatiotemporal dynamics of the Southern California Asian citrus psyllid (Diaphorina citri) invasion.

    Science.gov (United States)

    Bayles, Brett R; Thomas, Shyam M; Simmons, Gregory S; Grafton-Cardwell, Elizabeth E; Daugherty, Mathew P

    2017-01-01

    Biological invasions are governed by spatial processes that tend to be distributed in non-random ways across landscapes. Characterizing the spatial and temporal heterogeneities of the introduction, establishment, and spread of non-native insect species is a key aspect of effectively managing their geographic expansion. The Asian citrus psyllid (Diaphorina citri), a vector of the bacterium associated with huanglongbing (HLB), poses a serious threat to commercial and residential citrus trees. In 2008, D. citri first began expanding northward from Mexico into parts of Southern California. Using georeferenced D. citri occurrence data from 2008-2014, we sought to better understand the extent of the geographic expansion of this invasive vector species. Our objectives were to: 1) describe the spatial and temporal distribution of D. citri in Southern California, 2) identify the locations of statistically significant D. citri hotspots, and 3) quantify the dynamics of anisotropic spread. We found clear evidence that the spatial and temporal distribution of D. citri in Southern California is non-random. Further, we identified the existence of statistically significant hotspots of D. citri occurrence and described the anisotropic dispersion across the Southern California landscape. For example, the dominant hotspot surrounding Los Angeles showed rapid and strongly asymmetric spread to the south and east. Our study demonstrates the feasibility of quantitative invasive insect risk assessment with the application of a spatial epidemiology framework.

  16. Spatiotemporal dynamics of the Southern California Asian citrus psyllid (Diaphorina citri) invasion

    Science.gov (United States)

    Thomas, Shyam M.; Simmons, Gregory S.; Grafton-Cardwell, Elizabeth E.; Daugherty, Mathew P.

    2017-01-01

    Biological invasions are governed by spatial processes that tend to be distributed in non-random ways across landscapes. Characterizing the spatial and temporal heterogeneities of the introduction, establishment, and spread of non-native insect species is a key aspect of effectively managing their geographic expansion. The Asian citrus psyllid (Diaphorina citri), a vector of the bacterium associated with huanglongbing (HLB), poses a serious threat to commercial and residential citrus trees. In 2008, D. citri first began expanding northward from Mexico into parts of Southern California. Using georeferenced D. citri occurrence data from 2008–2014, we sought to better understand the extent of the geographic expansion of this invasive vector species. Our objectives were to: 1) describe the spatial and temporal distribution of D. citri in Southern California, 2) identify the locations of statistically significant D. citri hotspots, and 3) quantify the dynamics of anisotropic spread. We found clear evidence that the spatial and temporal distribution of D. citri in Southern California is non-random. Further, we identified the existence of statistically significant hotspots of D. citri occurrence and described the anisotropic dispersion across the Southern California landscape. For example, the dominant hotspot surrounding Los Angeles showed rapid and strongly asymmetric spread to the south and east. Our study demonstrates the feasibility of quantitative invasive insect risk assessment with the application of a spatial epidemiology framework. PMID:28278188

  17. Interband cascade (IC) photovoltaic (PV) architecture for PV devices

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Rui Q.; Tian, Zhaobing; Mishima, Tetsuya D.; Santos, Michael B.; Johnson, Matthew B.; Klem, John F.

    2015-10-20

    A photovoltaic (PV) device, comprising a PV interband cascade (IC) stage, wherein the IC PV stage comprises an absorption region with a band gap, the absorption region configured to absorb photons, an intraband transport region configured to act as a hole barrier, and an interband tunneling region configured to act as an electron barrier. An IC PV architecture for a photovoltaic device, the IC PV architecture comprising an absorption region, an intraband transport region coupled to the absorption region, and an interband tunneling region coupled to the intraband transport region and to the adjacent absorption region, wherein the absorption region, the intraband transport region, and the interband tunneling region are positioned such that electrons will flow from the absorption region to the intraband transport region to the interband tunneling region.

  18. Acaricidal Activity of Boenninghausenia sessilicarpa Against Panonychus citri

    Institute of Scientific and Technical Information of China (English)

    YANG Hui-zhi; HU Jun-hua; LI Qing; LI Hong-jun; LIU Hao-qiang; YAO Ting-shan; RAN Chun; LEI Hui-de

    2009-01-01

    Acaricidal activity of Boenninghausenia sessilicarpa against Panonychus citri was tested in the laboratory.Four solvents were used to prepare crude extracts,petroleum ether,chloroform,ethyl acetate,and ethanol,among which ethanol was the most effective one.The results suggested that ethanol extracts of B.sessilicarpa had eminent acaricidal and ovicidal activities.Concentrated extracts were prepared using petroleum ether,chloroform,ethyl acetate,or distilled water as solvent.Mite mortality rates in the concentrated extracts by petroleum ether,chloroform,or distilled water were significantly lower than those by ethyl acetate.The LC50 values of eggs and female mites were 0.7639 and 1.1033 mg mL-1,respectively.After liquid chromatography and thin layer chromatography,the concentrated extracts were separated into 14 groups of fractions and further tests for their acaricidal and ovicidal activities were conducted.Fraction 2 was found to possess higher acaricidal and ovicidal activities.The mortality of eggs and adult mites were 85.83 and 63.07%,respectively.Moreover,fraction 2 showed moderate oviposition inhibition effect (0.8795) against P.citri when the used dose Was higher than 2.5 mg mL-1.

  19. Different transcriptional response to Xanthomonas citri subsp. citri between kumquat and sweet orange with contrasting canker tolerance.

    Directory of Open Access Journals (Sweden)

    Xing-Zheng Fu

    Full Text Available Citrus canker disease caused by Xanthomonas citri subsp. citri (Xcc is one of the most devastating biotic stresses affecting the citrus industry. Meiwa kumquat (Fortunella crassifolia is canker-resistant, while Newhall navel orange (Citrus sinensis Osbeck is canker-sensitive. To understand the molecular mechanisms underlying the differences in responses to Xcc, transcriptomic profiles of these two genotypes following Xcc attack were compared by using the Affymetrix citrus genome GeneChip. A total of 794 and 1324 differentially expressed genes (DEGs were identified as canker-responsive genes in Meiwa and Newhall, respectively. Of these, 230 genes were expressed in common between both genotypes, while 564 and 1094 genes were only significantly expressed in either Meiwa or Newhall. Gene ontology (GO annotation and Singular Enrichment Analysis (SEA of the DEGs showed that genes related to the cell wall and polysaccharide metabolism were induced for basic defense in both Meiwa and Newhall, such as chitinase, glucanase and thaumatin-like protein. Moreover, apart from inducing basic defense, Meiwa showed specially upregulated expression of several genes involved in the response to biotic stimulus, defense response, and cation binding as comparing with Newhall. And in Newhall, abundant photosynthesis-related genes were significantly down-regulated, which may be in order to ensure the basic defense. This study revealed different molecular responses to canker disease in Meiwa and Newhall, affording insight into the response to canker and providing valuable information for the identification of potential genes for engineering canker tolerance in the future.

  20. Effect of X-irradiation on Citrus Canker Pathogen Xanthomonas citri subsp. citri of Satsuma Mandarin Fruits

    Directory of Open Access Journals (Sweden)

    Min-A Song

    2015-12-01

    Full Text Available Citrus canker caused by Xanthomonas citri subsp. citri (Xcc is one of the most important bacterial diseases of citrus. Because citrus canker is not found in many countries including European Union and Australia, Xcc is strictly regulated in order to prevent its spread. In this study, the effects of X-irradiation on Xcc growth either in the suspension or on the surface of citrus fruits were investigated. The suspension containing 1×10⁷ cfu/ml of Xcc was irradiated with different absorbed doses of X-irradiation ranging from 50 to 400 Gy. The results showed that Xcc was fully dead at 400 Gy of X-irradiation. To determine the effect of X-irradiation on quarantine, the Xcc-inoculated citrus fruits were irradiated with different X-ray doses at which Xcc was completely inhibited by an irradiation dose of 250 Gy. The D₁₀ value for Xcc on citrus fruits was found to be 97 Gy, indicating the possibility of direct application on citrus quarantine without any side sterilizer. Beside, presence of Xcc on the surface of asymptomatic citrus fruits obtained from citrus canker-infected orchards was noted. It indicated that the exporting citrus fruits need any treatment so that Xcc on the citrus fruits should be completely eliminated. Based on these results, ionizing radiation can be considered as an alternative method of eradicating Xcc for export of citrus fruits.

  1. Closely-related Xanthomonas citri subsp. citri isolates trigger distinct histological and transcriptional responses in Citrus limon

    Directory of Open Access Journals (Sweden)

    Ingrid Georgina Orce

    Full Text Available ABSTRACT Citrus canker, caused by Xanthomonas citri subsp. citri (Xcc, has an important economic impact on the citrus industry. Extensive information is available about the disease but, nevertheless, the study of plant-pathogen interactions could provide new information in the understanding of citrus canker disease. A new isolate has been identified, Xcc AT, which has a high genetic similarity (> 90 % to the virulent Xcc T strain based on genetic clustering analyses of the rep-PCR fingerprinting patterns, but it does not produce cankerous lesions in Citrus limon. In this study, we compared C. limon responses to Xcc AT and to the virulent Xcc T strain at both histological and transcriptional levels. Histologically, leaves inoculated with Xcc AT exhibited neither a typical disordering of the spongy mesophyll, nor a swelling of epidermis. A particular content (undetermined was also found in mesophyll cells near the stomata, together with increased starch accumulation. The transcriptomic profiles were compared by cDNA-AFLP technique. A total of 121 fragments derived from transcript (TDF were either specifically induced or repressed by the isolates, and 62 were sequenced. Analysis of global expression identified different classes of genes known to be involved in plant-pathogen interactions. This study constitutes the first approach of the specific interaction between the avirulent Xcc AT isolate and C. limon.

  2. Speedometers for PV generators; Drehzahlmesser fuer PV-Generatoren

    Energy Technology Data Exchange (ETDEWEB)

    Fritze, Peter; Weinreich, Bernhard [Solarschmiede GmbH, Muenchen (Germany). Engineering-Abt.

    2011-05-31

    To measure the generator power of an installed PV system, it is not enough to look into the specifications of hte module producers. Fast and independent data can be provided by characteristic curve meters.

  3. PV in a sports arena; PV im Hexenkessel

    Energy Technology Data Exchange (ETDEWEB)

    Hoeche, B.

    2008-05-19

    The German soccer club Werder Bremen is reconstructing its stadium. Apart from higher spectator comfort and a better atmosphere, there will also be PV systems on the roof and external walls of the arena. (orig.)

  4. Geographic Distribution of Habitat, Development, and Population Growth Rates of the Asian Citrus Psyllid, Diaphorina citri, in Mexico

    OpenAIRE

    López-Collado, José; Isabel López-Arroyo, J.; Robles-García, Pedro L.; Márquez-Santos, Magdalena

    2013-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is an introduced pest in Mexico and a vector of huanglongbing, a lethal citrus disease. Estimations of the habitat distribution and population growth rates of D. citri are required to establish regional and areawide management strategies and can be used as a pest risk analysis tools. In this study, the habitat distribution of D. citri in Mexico was computed with MaxEnt, an inductive, machine-learning program that uses...

  5. Use of recombinant tobacco mosaic virus to achieve RNA interference in plants against the citrus mealybug, Planococcus citri (Hemiptera: Pseudococcidae.

    Directory of Open Access Journals (Sweden)

    Arif Muhammad Khan

    Full Text Available The citrus mealybug, Planococcus citri, is an important plant pest with a very broad plant host range. P. citri is a phloem feeder and loss of plant vigor and stunting are characteristic symptoms induced on a range of host plants, but P. citri also reduces fruit quality and causes fruit drop leading to significant yield reductions. Better strategies for managing this pest are greatly needed. RNA interference (RNAi is an emerging tool for functional genomics studies and is being investigated as a practical tool for highly targeted insect control. Here we investigated whether RNAi effects can be induced in P. citri and whether candidate mRNAs could be identified as possible targets for RNAi-based P. citri control. RNAi effects were induced in P. citri, as demonstrated by specific target reductions of P. citri actin, chitin synthase 1 and V-ATPase mRNAs after injection of the corresponding specific double-stranded RNA inducers. We also used recombinant Tobacco mosaic virus (TMV to express these RNAi effectors in Nicotiana benthamiana plants. We found that P. citri showed lower fecundity and pronounced death of crawlers after feeding on recombinant TMV-infected plants. Taken together, our data show that actin, chitin synthase 1 and V-ATPase mRNAs are potential targets for RNAi against P. citri, and that recombinant TMV is an effective tool for evaluating candidate RNAi effectors in plants.

  6. Use of recombinant tobacco mosaic virus to achieve RNA interference in plants against the citrus mealybug, Planococcus citri (Hemiptera: Pseudococcidae).

    Science.gov (United States)

    Khan, Arif Muhammad; Ashfaq, Muhammad; Kiss, Zsofia; Khan, Azhar Abbas; Mansoor, Shahid; Falk, Bryce W

    2013-01-01

    The citrus mealybug, Planococcus citri, is an important plant pest with a very broad plant host range. P. citri is a phloem feeder and loss of plant vigor and stunting are characteristic symptoms induced on a range of host plants, but P. citri also reduces fruit quality and causes fruit drop leading to significant yield reductions. Better strategies for managing this pest are greatly needed. RNA interference (RNAi) is an emerging tool for functional genomics studies and is being investigated as a practical tool for highly targeted insect control. Here we investigated whether RNAi effects can be induced in P. citri and whether candidate mRNAs could be identified as possible targets for RNAi-based P. citri control. RNAi effects were induced in P. citri, as demonstrated by specific target reductions of P. citri actin, chitin synthase 1 and V-ATPase mRNAs after injection of the corresponding specific double-stranded RNA inducers. We also used recombinant Tobacco mosaic virus (TMV) to express these RNAi effectors in Nicotiana benthamiana plants. We found that P. citri showed lower fecundity and pronounced death of crawlers after feeding on recombinant TMV-infected plants. Taken together, our data show that actin, chitin synthase 1 and V-ATPase mRNAs are potential targets for RNAi against P. citri, and that recombinant TMV is an effective tool for evaluating candidate RNAi effectors in plants.

  7. Anthrax Pathogenesis.

    Science.gov (United States)

    Moayeri, Mahtab; Leppla, Stephen H; Vrentas, Catherine; Pomerantsev, Andrei P; Liu, Shihui

    2015-01-01

    Anthrax is caused by the spore-forming, gram-positive bacterium Bacillus anthracis. The bacterium's major virulence factors are (a) the anthrax toxins and (b) an antiphagocytic polyglutamic capsule. These are encoded by two large plasmids, the former by pXO1 and the latter by pXO2. The expression of both is controlled by the bicarbonate-responsive transcriptional regulator, AtxA. The anthrax toxins are three polypeptides-protective antigen (PA), lethal factor (LF), and edema factor (EF)-that come together in binary combinations to form lethal toxin and edema toxin. PA binds to cellular receptors to translocate LF (a protease) and EF (an adenylate cyclase) into cells. The toxins alter cell signaling pathways in the host to interfere with innate immune responses in early stages of infection and to induce vascular collapse at late stages. This review focuses on the role of anthrax toxins in pathogenesis. Other virulence determinants, as well as vaccines and therapeutics, are briefly discussed.

  8. PSCAD Modules Representing PV Generator

    Energy Technology Data Exchange (ETDEWEB)

    Muljadi, E.; Singh, M.; Gevorgian, V.

    2013-08-01

    Photovoltaic power plants (PVPs) have been growing in size, and the installation time is very short. With the cost of photovoltaic (PV) panels dropping in recent years, it can be predicted that in the next 10 years the contribution of PVPs to the total number of renewable energy power plants will grow significantly. In this project, the National Renewable Energy Laboratory (NREL) developed a dynamic modeling of the modules to be used as building blocks to develop simulation models of single PV arrays, expanded to include Maximum Power Point Tracker (MPPT), expanded to include PV inverter, or expanded to cover an entire PVP. The focus of the investigation and complexity of the simulation determines the components that must be included in the simulation. The development of the PV inverter was covered in detail, including the control diagrams. Both the current-regulated voltage source inverter and the current-regulated current source inverter were developed in PSCAD. Various operations of the PV inverters were simulated under normal and abnormal conditions. Symmetrical and unsymmetrical faults were simulated, presented, and discussed. Both the three-phase analysis and the symmetrical component analysis were included to clarify the understanding of unsymmetrical faults. The dynamic model validation was based on the testing data provided by SCE. Testing was conducted at SCE with the focus on the grid interface behavior of the PV inverter under different faults and disturbances. The dynamic model validation covers both the symmetrical and unsymmetrical faults.

  9. Biology of Diaphorina citri (Homoptera: Psyllidae) on four host plants.

    Science.gov (United States)

    Tsai, J H; Liu, Y H

    2000-12-01

    The biology of the citrus psyllid Diaphorina citri Kuwayama was studied at 25 degrees C on four commonly grown citrus and related plants [rough lemon, Citrus jambhiri Lush; sour orange, C aurantium L.; grapefruit, C. paradisi Macfadyen; and orange jessamine, Murraya paniculata (L.) Jack] in the laboratory. The biological characteristics of each life stage are described. The average egg incubation periods on orange jessamine, grapefruit, rough lemon, and sour orange varied very little (4.1-4.2 d). The average nymphal developmental periods on these four host plants were essentially the same except the fifth stadium. Survival of immatures on orange jessamine, grapefruit, rough lemon, and sour orange was 75.4, 84.6, 78.3, and 68.6%, respectively. Female adults lived an average of 39.7, 39.7, 47.6, and 43.7 d on these respective host plants. The average number of eggs laid per female on grapefruit (858 eggs) was significantly more than those on other hosts (P < 0.05). The intrinsic rate of natural increase (r(m)) for D. citri on grapefruit was highest. Jackknife estimates of r(m) varied from 0.188 on grapefruit to 0.162 on orange jessamine and rough lemon. The mean population generation time on these hosts ranged from 31.6 to 34.1 d. The continuous flushes produced by orange jessamine could play an important role in maintaining high populations of this vector when the new flushes are not available in the commercial citrus groves.

  10. Locational Sensitivity Investigation on PV Hosting Capacity and Fast Track PV Screening

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Fei; Mather, Barry; Ainsworth, Nathan; Gotseff, Peter; Baker, Kyri

    2016-05-05

    A 15% PV penetration threshold is commonly used by utilities to define photovoltaic (PV) screening methods where PV penetration is defined as the ratio of total solar PV capacity on a line section to peak load. However, this method doesn't take into account PV locational impact or feeder characteristics that could strongly change the feeder's capability to host PVs. This paper investigates the impact of PV location and phase connection type on PV hosting capacity, and then proposes a fast-track PV screening approach that leverages various PV hosting capacity metric responding to different PV locations and types. The proposed study could help utilities to evaluate PV interconnection requests and also help increase the PV hosting capacity of distribution feeders without adverse impacts on system voltages.

  11. PV system testing and standards

    Science.gov (United States)

    DeBlasio, Richard

    1999-03-01

    The U.S. Department of Energy (DOE) PV Program System Performance and Engineering Project is being conducted by The National Renewable Energy Laboratory (NREL), Sandia National Laboratories (SNL), Southwest Technology Development Institute (SWTDI), and Florida Solar Energy Center (FSEC). It provides PV system, subsystem, and component-level technology-performance characterization testing; test-method development and validation; national and international consensus standards and codes development, test-facility product certification, and laboratory-accreditation program implementation; and information exchange and technical assistance to the PV community. Emphasis is placed on reducing technical and infrastructural barriers to system acceptance, reducing life-cycle cost of systems, providing systems-engineering best practices and guidelines, and leading the national effort in performance and reliability testing, and consensus standards, codes, and certification program development and implementation—thereby ensuring that PV systems meet customers' needs and expectations. A summary of project activities, accomplishments, and future plans is provided and highlighted by an overview of PV system test-procedure and standards development.

  12. Low concentrator PV optics optimization

    Science.gov (United States)

    Sharp, Leonard; Chang, Ben

    2008-08-01

    Purpose: Cost reduction is a major focus of the solar industry. Thin film technologies and concentration systems are viable ways to reducing cost, with unique strengths and weakness for both. Most of the concentrating PV work focuses on high concentration systems for reducing energy cost. Meanwhile, many believe that low concentrators provide significant cost reduction potential while addressing the mainstream PV market with a product that acts as a flat panel replacement. This paper analyzes the relative benefit of asymmetric vs. symmetric optics for low-concentrators in light of specific PV applications. Approach: Symmetric and asymmetric concentrating PV module performance is evaluated using computer simulation to determine potential value across various geographic locations and applications. The selected optic design is modeled against standard cSi flat panels and thin film to determine application fit, system level energy density and economic value. Results: While symmetric designs may seem ideal, asymmetric designs have an advantage in energy density. Both designs are assessed for aperture, optimum concentration ratio, and ideal system array configuration. Analysis of performance across climate specific effects (diffuse, direct and circumsolar) and location specific effects (sunpath) are also presented. The energy density and energy production of low concentrators provide a compelling value proposition. More significantly, the choice of optics for a low concentrating design can affect real world performance. With the goal of maximizing energy density and return on investment, this paper presents the advantages of asymmetric optic concentration and illustrates the value of this design within specific PV applications.

  13. Living on the Edges: Spatial Niche Occupation of Asian Citrus Psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae, in Citrus Groves.

    Directory of Open Access Journals (Sweden)

    Mamoudou Sétamou

    Full Text Available The spatial niche occupation of the Asian citrus psyllid, Diaphorina citri Kuwayama, 1908, was evaluated to determine its field colonization and food resource exploitation strategies in citrus groves. Mature grapefruit and sweet orange groves were surveyed as part of an area-wide program in 2009-2010 to determine D. citri population densities and between-tree distribution. In both cultivars, significantly more psyllids were found on perimeter trees throughout the study period suggesting a strong edge effect in D. citri distribution in the groves. D. citri densities and infestation levels gradually declined from the edge to the center of grove. Higher numbers of D. citri were recorded on trees located on the east and south sides of the groves than those on the west and north sides. Citrus groves located at the outer edge of the study with at least one side non-surrounded to other citrus groves harbored significantly more D. citri than groves located within the block cluster and entirely surrounded by other groves. In detailed field studies during 2012, infestation of D. citri started from border trees in the grove where possibly one generation is completed before inner trees become infested. In addition, psyllid densities decreased significantly with increasing distance from the grove edge. Using the selection index, D citri exhibited a strong niche occupation preference for border trees.

  14. [Analysis on medication rules of state medical master Yan Zhenghua from prescriptions with citri reticulatae pericarpium based on data mining].

    Science.gov (United States)

    Wu, Jia-Rui; Guo, Wei-Xian; Zhang, Bing; Zhang, Xiao-Meng; Yang, Bing; Sheng, Xiao-Guang

    2014-02-01

    The prescriptions containing pericarpium citri reticulatae that built by Professor. Yan were collected to build a database based on traditional Chinese medicine (TCM) inheritance assist system. After analyzed by data mining, such as apriori algorithm, the frequency of single medicine, the frequency of drug combination, the association rules between drugs and core drug combinations can be get from the database. Through the analysis of 1 027 prescriptions with pericarpium citri reticulatae, these prescriptions were commonly used to treat stomach aches, cough and other syndromes. The most frequency drug combinations were "Citri Reticulatae Pericarpium-Poria", "Paeoniae Radix Rubra-Citri Reticulatae Pericarpium" and so on. The drug association rules that the confidence was 1 were "Glycyrrhizae Radix ex Rhizoma --> Citri Reticulatae Pericarpium", "Paeoniae Alba Radix-Cyperi Rhizoma --> Citri Reticulatae Pericarpium", "Poria --> Citri Reticulatae Pericarpium", and so on. The drugs in the prescriptions containing pericarpium citri reticulatae that built by Professor Yan mostly had the effects of regulating the flow of Qi and invigorate blood circulation, which reflected the clearly thought when making prescriptions.

  15. Within-orchard edge effects of the azimuth of the sun on Diaphorina citri adults in mature orchards

    Science.gov (United States)

    Huanglongbing (HLB) has been considered the most devastating disease of citrus. The bacterium and vector associated with HLB in Florida are ‘Candidatus Liberibacter asiaticus’ and Diaphorina citri (Asian citrus psyllid), respectively. D. citri is positively phototropic, and higher populations have b...

  16. Diaphorina citri (Hemiptera: Liviidae) responses to microcontroller-buzzer communication signals of potential use in vibration traps

    Science.gov (United States)

    Monitoring of Diaphorina citri Kuwayama populations is an important component of efforts to reduce damage caused by huanglongbing, a devastating disease it vectors in citrus groves. Currently, D. citri is monitored primarily by unbaited sticky traps or visual inspection of trees. A potentially more ...

  17. Survey of endosymbionts in the Diaphorina citri metegenome and assembly of a Wolbachia wDi draft genome

    Science.gov (United States)

    Diaphorina citri, the Asian citrus psyllid,(Hemiptera) is the insect vector of Candidatus Liberibacter asiaticus, the presumed cause of citrus greening disease, known as huanglongbing. Sequencing of the Diaphorina citri metagenome has been initiated to gain better understanding of the biology of D. ...

  18. Chemical and behavioral analysis of the cuticular hydrocarbons from Asian citrus psyllid, Diaphorina citri.

    Science.gov (United States)

    Mann, Rajinder S; Rouseff, Russell L; Smoot, Jack; Rao, Nandikeswara; Meyer, Wendy L; Lapointe, Stephen L; Robbins, Paul S; Cha, Dong; Linn, Charles E; Webster, Francis X; Tiwari, Siddharth; Stelinski, Lukasz L

    2013-06-01

    Huanglongbing (HLB) is the most destructive disease of citrus worldwide. The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the vector of the phloem-inhabiting bacterium, Candidatus Liberibacter asiaticus, which is presumed to cause HLB in Florida citrus. Laboratory and field studies were conducted to examine the behavioral responses of male and female D. citri to their cuticular extracts. In olfactometer assays, more male D. citri were attracted to one, five, or 10 female cuticular extract equivalent units than blank controls. The results were confirmed in field studies in which clear or yellow traps baited with 10 female cuticular extract equivalent units attracted proportionately more males than clear traps baited with male cuticular extract or unbaited traps. Analyses of cuticular constituents of male and female D. citri revealed differences between the sexes in chemical composition of their cuticular extracts. Laboratory bioassays with synthetic chemicals identified from cuticular extracts indicated that dodecanoic acid attracted more males than clean air. Traps baited with dodecanoic acid did not increase total catch of D. citri as compared with blank traps at the dosages tested; however, the sex ratio of psyllid catch was male biased on traps baited with the highest lure loading dosage tested (10.0 mg). © 2012 The Authors Insect Science © 2012 Institute of Zoology, Chinese Academy of Sciences.

  19. Flexible packaging for PV modules

    Science.gov (United States)

    Dhere, Neelkanth G.

    2008-08-01

    Economic, flexible packages that provide needed level of protection to organic and some other PV cells over >25-years have not yet been developed. However, flexible packaging is essential in niche large-scale applications. Typical configuration used in flexible photovoltaic (PV) module packaging is transparent frontsheet/encapsulant/PV cells/flexible substrate. Besides flexibility of various components, the solder bonds should also be flexible and resistant to fatigue due to cyclic loading. Flexible front sheets should provide optical transparency, mechanical protection, scratch resistance, dielectric isolation, water resistance, UV stability and adhesion to encapsulant. Examples are Tefzel, Tedlar and Silicone. Dirt can get embedded in soft layers such as silicone and obscure light. Water vapor transmittance rate (WVTR) of polymer films used in the food packaging industry as moisture barriers are ~0.05 g/(m2.day) under ambient conditions. In comparison, light emitting diodes employ packaging components that have WVTR of ~10-6 g/(m2.day). WVTR of polymer sheets can be improved by coating them with dense inorganic/organic multilayers. Ethylene vinyl acetate, an amorphous copolymer used predominantly by the PV industry has very high O2 and H2O diffusivity. Quaternary carbon chains (such as acetate) in a polymer lead to cleavage and loss of adhesional strength at relatively low exposures. Reactivity of PV module components increases in presence of O2 and H2O. Adhesional strength degrades due to the breakdown of structure of polymer by reactive, free radicals formed by high-energy radiation. Free radical formation in polymers is reduced when the aromatic rings are attached at regular intervals. This paper will review flexible packaging for PV modules.

  20. Comparison of Pyranometers vs. PV Reference Cells for Evaluation of PV Array Performance

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, L.; Gostein, M.; Emery, K.

    2012-09-01

    As the photovoltaics (PV) industry has grown, the need for accurately monitoring the solar resource of PV power plants has increased. Historically, the PV industry has relied on thermopile pyranometers for irradiance measurements, and a large body of historical irradiance data taken with pyranometers exists. However, interest in PV reference devices is increasing. In this paper, we discuss why PV reference devices are better suited for PV applications, and estimate the typical uncertainties in irradiance measurements made with both pyranometers and PV reference devices. We assert that the quantity of interest in monitoring a PV power plant is the equivalent irradiance under the IEC 60904-3 reference solar spectrum that would produce the same electrical response in the PV array as the incident solar radiation. For PV-plant monitoring applications, we find the uncertainties in irradiance measurements of this type to be on the order of +/-5% for thermopile pyranometers and +/-2.4% for PV reference devices.

  1. Solar PV. Innovators talking; Zon PV. Innovators aan het woord

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-02-15

    Qualitative studies have been conducted of the results of completed projects focused on energy innovation, spread over the seven themes of the top sector Energy: Energy saving in industry, Energy conservation in the built environment, Gas, Bio-energy, Smart grids, Offshore Wind, Solar PV. This provides insight into the follow-up activities and lessons of some EOS (Energy Research Subsidy) completed projects with the aim to inspire, connect and strengthen the TKIs (Topconsortia for Knowledge and Innovation) and individual companies and researchers working on energy innovation. This report concerns the research on solar PV [Dutch] Er is een kwalitatief onderzoek uitgevoerd naar de resultaten van afgeronde projecten gericht op energie-innovatie, verdeeld over de zeven thema's van de topsector Energie: Energiebesparing in de industrie; Energiebesparing in de gebouwde omgeving; Gas; Bio-energie; Smart grids; Wind op zee; Zon-pv. Daarmee wordt inzicht gegeven in de vervolgactiviteiten en lessen van een aantal afgesloten EOS-projecten (Energie Onderzoek Subsidie) met het oog op het inspireren, verbinden en versterken van de TKI's (Topconsortia voor Kennis en Innovatie) en individuele bedrijven en onderzoekers die werken aan energie-innovatie. Dit rapport betreft het onderzoek naar zon PV.

  2. Van lPv4 naar lPv6

    NARCIS (Netherlands)

    Luiijf, H.A.M.

    2008-01-01

    Organisaties die het Internet Protocol(IP) gebruiken voor beveiligingsdoeleinden en aanbieders van beveiligingsproducten ontkomen de komende jaren niet aan de overgang naar het nieuwe protocol lPv6. Enerzijds is het gelukkig dat die overgang niet op één dag wereldwijd zal plaatsvinden, er is geen 'I

  3. A Virulence-Reducing Mutation in the Postharvest Citrus Pathogen Alternaria citri.

    Science.gov (United States)

    Katoh, H; Isshiki, A; Masunaka, A; Yamamoto, H; Akimitsu, K

    2006-09-01

    ABSTRACT Alternaria citri causes Alternaria black rot, a postharvest fruit disease, on a broad range of citrus cultivars. We previously described that an endopolygalacturonase minus mutant of A. citri caused significantly less black rot in citrus fruit. To search for other essential factors causing symptoms in addition to endopolygalacturonase, a random mutation analysis of pathogenicity was performed using restriction enzyme-mediated integration. Three isolates among 1,694 transformants of A. citri had a loss in pathogenicity in a citrus peel assay, and one of these three mutants was a histidine auxotroph. Gene AcIGPD that encodes imidazole glycerol phosphate dehydratase, the sixth enzyme in the histidine biosynthetic pathway, was cloned, and the mutant containing the disrupted target gene, AcIGPD, caused less black rot.

  4. Progress & Frontiers in PV Performance

    Energy Technology Data Exchange (ETDEWEB)

    Deline, Chris; DiOrio, Nick; Jordan, Dirk; Toor, Fatima

    2016-09-12

    PowerPoint slides for a presentation given at Solar Power International 2016. Presentation includes System Advisor Model (SAM) introduction and battery modeling, bifacial PV modules and modeling, shade modeling and module level power electronics (MLPE), degradation rates, and PVWatts updates and validation.

  5. PV gold rush in Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Becker, Daniela

    2011-07-01

    As a result of the Green Energy Act, the installed PV capacity in the Canadian province of Ontario has tripled in the year 2010. A generous feed-in tariff, aiming at maximum local added value, has attracted numerous international manufacturers. However, the rigorous rules committing the companies to 60 % inland production have provoked harsh criticism. (orig.)

  6. The case for better PV forecasting

    DEFF Research Database (Denmark)

    Alet, Pierre-Jean; Efthymiou, Venizelos; Graditi, Giorgio

    2016-01-01

    Rising levels of PV penetration mean increasingly sophisticated forecasting technologies are needed to maintain grid stability and maximise the economic value of PV systems. The Grid Integration working group of the European Technology and Innovation Platform – Photovoltaics (ETIP PV) shares...... the results of its ongoing research into the advantages and limitations of current forecasting technologies....

  7. Host plant affects morphometric variation of Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Paris, Thomson M; Allan, Sandra A; Hall, David G; Hentz, Matthew G; Hetesy, Gabriella; Stansly, Philip A

    2016-01-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is one of the most serious citrus pests worldwide due to its role as vector of huanglongbing or citrus greening disease. While some optimal plant species for ACP oviposition and development have been identified, little is known of the influence of host plants on ACP size and shape. Our goal was to determine how size and shape of ACP wing and body size varies when development occurs on different host plants in a controlled rearing environment. ACP were reared on six different rutaceous species; Bergera koenigii, Citrus aurantifolia, Citrus macrophylla, Citrus maxima, Citrus taiwanica and Murraya paniculata. Adults were examined for morphometric variation using traditional and geometric analysis based on 12 traits or landmarks. ACP reared on C. taiwanica were consistently smaller than those reared on the other plant species. Wing aspect ratio also differed between C. maxima and C. taiwanica. Significant differences in shape were detected with those reared on M. paniculata having narrower wings than those reared on C. macrophylla. This study provides evidence of wing size and shape differences of ACP based on host plant species which potentially may impact dispersal. Further study is needed to determine if behavioral and physiological differences are associated with the observed phenotypic differences.

  8. Host plant affects morphometric variation of Diaphorina citri (Hemiptera: Liviidae

    Directory of Open Access Journals (Sweden)

    Thomson M. Paris

    2016-11-01

    Full Text Available The Asian citrus psyllid (ACP, Diaphorina citri Kuwayama, is one of the most serious citrus pests worldwide due to its role as vector of huanglongbing or citrus greening disease. While some optimal plant species for ACP oviposition and development have been identified, little is known of the influence of host plants on ACP size and shape. Our goal was to determine how size and shape of ACP wing and body size varies when development occurs on different host plants in a controlled rearing environment. ACP were reared on six different rutaceous species; Bergera koenigii, Citrus aurantifolia, Citrus macrophylla, Citrus maxima, Citrus taiwanica and Murraya paniculata. Adults were examined for morphometric variation using traditional and geometric analysis based on 12 traits or landmarks. ACP reared on C. taiwanica were consistently smaller than those reared on the other plant species. Wing aspect ratio also differed between C. maxima and C. taiwanica. Significant differences in shape were detected with those reared on M. paniculata having narrower wings than those reared on C. macrophylla. This study provides evidence of wing size and shape differences of ACP based on host plant species which potentially may impact dispersal. Further study is needed to determine if behavioral and physiological differences are associated with the observed phenotypic differences.

  9. First record of Diaphorina citri (Hemiptera: Psyllidae) in Ecuador infesting urban citrus and orange jasmine trees.

    Science.gov (United States)

    Cornejo, J F; Chica, E J

    2014-01-01

    Adults and nymphs of the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), were collected in the Guayaquil, Samborondón, and Durán cantons in coastal Ecuador. Psyllids were found in high numbers in citrus (Citrus spp., Sapindales: Rutaceae) and orange jasmine (Murraya exotica [L.] Jack, Sapindales: Rutaceae) trees within the Guayaquil-Samborondon-Duran conurbation; however, none was found during scoutings in the main citrus producing areas in coastal Ecuador. To the best of our knowledge, this is the first report of D. citri in Ecuador and the Pacific coastal plain of South America.

  10. Grid Integrated Distributed PV (GridPV) Version 2.

    Energy Technology Data Exchange (ETDEWEB)

    Reno, Matthew J.; Coogan, Kyle

    2014-12-01

    This manual provides the documentation of the MATLAB toolbox of functions for using OpenDSS to simulate the impact of solar energy on the distribution system. The majority of the functio ns are useful for interfacing OpenDSS and MATLAB, and they are of generic use for commanding OpenDSS from MATLAB and retrieving information from simulations. A set of functions is also included for modeling PV plant output and setting up the PV plant in th e OpenDSS simulation. The toolbox contains functions for modeling the OpenDSS distribution feeder on satellite images with GPS coordinates. Finally, example simulations functions are included to show potential uses of the toolbox functions. Each function i n the toolbox is documented with the function use syntax, full description, function input list, function output list, example use, and example output.

  11. Lightweight IMM PV Flexible Blanket Assembly

    Science.gov (United States)

    Spence, Brian

    2015-01-01

    Deployable Space Systems (DSS) has developed an inverted metamorphic multijunction (IMM) photovoltaic (PV) integrated modular blanket assembly (IMBA) that can be rolled or z-folded. This IMM PV IMBA technology enables a revolutionary flexible PV blanket assembly that provides high specific power, exceptional stowed packaging efficiency, and high-voltage operation capability. DSS's technology also accommodates standard third-generation triple junction (ZTJ) PV device technologies to provide significantly improved performance over the current state of the art. This SBIR project demonstrated prototype, flight-like IMM PV IMBA panel assemblies specifically developed, designed, and optimized for NASA's high-voltage solar array missions.

  12. Lightning protection of PV systems

    OpenAIRE

    Pons, Enrico; Tommasini, Riccardo

    2013-01-01

    Lightning strikes can affect photovoltaic (PV) generators and their installations, involving also the inverter's electronics. It is therefore necessary to evaluate the risk connected to lightning strikes in order to adopt the correct protective measures for the system. The Standard IEC (EN) 62305-2 reports the procedures for the risk calculation and for the choice of proper lightning protection systems. Usually the technical guidelines suggest protecting with SPDs (surge protective devices) b...

  13. Molecular Detection of Spiroplasma Citri Associated with Stubborn Disease in Citrus Orchards in Syria

    Science.gov (United States)

    Spiroplasma citri, a phloem-limited pathogen, causes citrus stubborn disease (CSD) and can be transmitted from plant to plant by several species of phloem-feeding leafhoppers. CSD is an important disorder in certain warm and arid citrus-growing areas, and its agent has been recorded from several Med...

  14. Gender differences and effect of photophase on Asian citrus psyllid (Diaphorina citri Kuwayama) feeding behavior

    Science.gov (United States)

    Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), thought to be primarily a phloem-feeding insect, transmits the presumptive pathogen for Huanglongbing, ‘Candidatus Liberibacter asiaticus’. Because this bacterium is restricted to the phloem and bacterial transmission is the res...

  15. Chemical and behavioral analysis of the cuticular hydrocarbons from Asian citrus psyllid, Diaphorina citri

    Institute of Scientific and Technical Information of China (English)

    Raiinder S.Mann; Russell L.Rouseff; Jack Smoot; Nandikeswara Rao; Wendy L.Meyer; Stephen L.Lapointe; Paul S.Robbins

    2013-01-01

    Huanglongbing (HLB) is the most destructive disease of citrus worldwide.The Asian citrus psyllid,Diaphorina citri Kuwayama (Hemiptera:Psyllidae),is the vector of the phloem-inhabiting bacterium,Candidatus Liberibacter asiaticus,which is presumed to cause HLB in Florida citrus.Laboratory and field studies were conducted to examine the behavioral responses of male and female D.citri to their cuticular extracts.In olfactometer assays,more male D.citri were attracted to one,five,or 10 female cuticular extract equivalent units than blank controls.The results were confirmed in field studies in which clear or yellow traps baited with 10 female cuticular extract equivalent units attracted proportionately more males than clear traps baited with male cuticular extract or unbaited traps.Analyses of cuticular constituents of male and female D.citri revealed differences between the sexes in chemical composition of their cuticular extracts.Laboratory bioassays with synthetic chemicals identified from cuticular extracts indicated that dodecanoic acid attracted more males than clean air.Traps baited with dodecanoic acid did not increase total catch of D.cirri as compared with blank traps at the dosages tested; however,the sex ratio of psyllid catch was male biased on traps baited with the highest lure loading dosage tested (10.0 mg).

  16. Geïntegreerde bestrijding van citruswolluis Planococcus citri in roos

    NARCIS (Netherlands)

    Pijnakker, J.; Leman, A.; Staaij, van der M.

    2011-01-01

    Referaat Sinds begin 2000 is citruswolluis, Planococcus citri (Risso), een van de belangrijkste plagen geworden in de rozenteelt onder glas. Telers kiezen voor een meer geïntegreerde aanpak om andere plagen onder controle te houden en stoppen met het reguliere gebruik van breedwerkende middelen. Hie

  17. Perspectives to the use of entomopathogenic fungi for biological control of Diaphorina citri in Mexico

    OpenAIRE

    Sánchez-Peña, S. R.; Guizar-Guzmán, L.; Torres-Acosta, R. I.; López-Arroyo, J. I.; Casique-Valdés, R.

    2014-01-01

    Entomopathogenic fungi are natural enemies of D. citri adults in Mexico. Natural prevalence (%) of fungi on live adults in central Veracruz (summer) and southern Tamaulipas (fall) were: Hirsutella citriformis (7-35); Isaria fumosorosea (5-15); Lecanicillium (2 in Tamaulipas), and Beauveria (

  18. Daily and seasonal patterns in abdomen color in Diaphoria citri (Hemiptera: Psyllidae)

    Science.gov (United States)

    Diaphorina citri Kuwayama, a psyllid vector of huanglongbing (citrus greening disease), exhibits three more or less distinct abdomen colors in the adult psyllid: gray/brown, blue/green, and orange/yellow. We explored the daily (in individuals in the laboratory) and seasonal (in a field population) p...

  19. An improved method of DNA extraction from Diaphorina citri for HLB detection

    Science.gov (United States)

    Huanglongbing (HLB) is a devastating disease of citrus that is transmitted by two citrus psyllids. Diaphorina citri transmits Candidatus Liberibacter asiaticus (Las) and Ca. L. americanus (Lam), and Trioza erytreae transmits Ca. L. africanus (Laf). Ca. Liberibacter species can be detected in DNA ex...

  20. Geïntegreerde bestrijding van citruswolluis Planococcus citri in roos

    NARCIS (Netherlands)

    Pijnakker, J.; Leman, A.; Hennekam, M.

    2013-01-01

    Citruswolluis, Planococcus citri (Risso), is een van de belangrijkste plagen geworden in de rozenteelt onder glas. Er is inmiddels veel praktijkervaring met de toepassing van biologische bestrijders om haarden uit te roeien. Voor de professionele tuinbouw is de effectiviteit van deze aanpak doorgaan

  1. Reduced Susceptibility to Xanthomonas citri in Transgenic Citrus Expressing the FLS2 Receptor From Nicotiana benthamiana.

    Science.gov (United States)

    Hao, Guixia; Pitino, Marco; Duan, Yongping; Stover, Ed

    2016-02-01

    Overexpression of plant pattern-recognition receptors by genetic engineering provides a novel approach to enhance plant immunity and broad-spectrum disease resistance. Citrus canker disease associated with Xanthomonas citri is one of the most important diseases damaging citrus production worldwide. In this study, we cloned the FLS2 gene from Nicotiana benthamiana cDNA and inserted it into the binary vector pBinPlus/ARS to transform Hamlin sweet orange and Carrizo citrange. Transgene presence was confirmed by polymerase chain reaction (PCR) and gene expression of NbFLS2 was compared by reverse transcription quantitative PCR. Reactive oxygen species (ROS) production in response to flg22Xcc was detected in transgenic Hamlin but not in nontransformed controls. Low or no ROS production was detected from nontransformed Hamlin seedlings challenged with flg22Xcc. Transgenic plants highly expressing NbFLS2 were selected and were evaluated for resistance to canker incited by X. citri 3213. Our results showed that the integration and expression of the NbFLS2 gene in citrus can increase canker resistance and defense-associated gene expression when challenged with X. citri. These results suggest that canker-susceptible Citrus genotypes lack strong basal defense induced by X. citri flagellin and the resistance of these genotypes can be enhanced by transgenic expression of the flagellin receptor from a resistant species.

  2. The genetic structure of an invasive pest, the Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae.

    Directory of Open Access Journals (Sweden)

    Aline S Guidolin

    Full Text Available The Asian citrus psyllid Diaphorina citri is currently the major threat to the citrus industry as it is the vector of Candidatus Liberibacter, the causal agent of huanglongbing disease (HLB. D. citri is native to Asia and now colonizes the Americas. Although it has been known in some countries for a long time, invasion routes remain undetermined. There are no efficient control methods for the HLB despite the intensive management tools currently in use. We investigated the genetic variability and structure of populations of D. citri to aid in the decision making processes toward sustainable management of this species/disease. We employed different methods to quantify and compare the genetic diversity and structure of D. citri populations among 36 localities in Brazil, using an almost complete sequence of the cytochrome oxidase I (COI gene. Our analyses led to the identification of two geographically and genetically structured groups. The indices of molecular diversity pointed to a recent population expansion, and we discuss the role of multiple invasion events in this scenario. We also argue that such genetic diversity and population structure may have implications for the best management strategies to be adopted for controlling this psyllid and/or the disease it vectors in Brazil.

  3. Molecular characterization of Wolbachia strains associated with the invasive Asian citrus psyllid Diaphorina citri in Brazil.

    Science.gov (United States)

    Guidolin, A S; Cônsoli, F L

    2013-02-01

    Wolbachia is a symbiont intensively studied due to its ability to interfere with their host's reproduction, and it has been recently proposed as an alternative tool to control insect pests or vectors of diseases. The Asian citrus psyllid Diaphorina citri is an important pest of citrus since it vectors the bacterium that causes the "Huanglongbing" disease in citrus. The frequency and diversity of Wolbachia associated with D. citri is unknown, limiting the utilization of Wolbachia as an alternative strategy for insect management. Thus, we aimed to determine the natural rate of infection, to characterize the Wolbachia strains associated with this psyllid by "multilocus sequencing typing" (MLST) and wsp analysis, and to verify the association of the symbiont to particular genotypes of the host. Analysis indicated Wolbachia infects 100 % of all specimens tested from all 15 sampled populations. MLST revealed the occurrence of five new sequence types (STs) of Wolbachia, while analysis based on the wsp sequences indicated only four different types of Wolbachia. ST-173 was predominant, while the remaining STs were population specific. Analysis of the host-symbiont relationship did not reveal any particular association of Wolbachia and haplotypes or a decrease in nucleotide diversity of D. citri in populations in which more than one ST was recorded. The consequences of the diversity of STs reported are still unknown, but the fact that Wolbachia infection is fixed and that there is one ST with a broad distribution highlights the use of this symbiont as an alternative strategy to control D. citri.

  4. Population ecology and phenology of Diaphorina citri (Hemiptera: Psyllidae) in two Florida citrus groves

    Science.gov (United States)

    Studies were conducted during 2005 and 2006 to assess population densities and phenology of the psyllid Diaphorina citri Kuwayama in citrus within east central Florida. Young, irrigated grapefruit and mature, non-irrigated orange trees were sampled weekly for eggs, nymphs and adults on flush shoots;...

  5. Chemical and behavioral analysis of the cuticular hydrocarbons from Asian citrus psyllid, Diaphorina citri

    Science.gov (United States)

    Huanglongbing (HLB) is the most destructive disease of citrus worldwide. Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is the vector of the phloem-inhabiting bacterium, Candidatus Liberibacter asiaticus, which is presumed to cause HLB. Laboratory and field studies were cond...

  6. Effects of temperature, photoperiod, and rainfall on morphometric variation of Diaphorina citri (Hemiptera: Liviidae)

    Science.gov (United States)

    Phenotypic plasticity provides a mechanism by which an organism can adapt to new or changing environments. Earlier studies have demonstrated the variability of Diaphorina citri Kuwayama (Asian citrus psyllid) population dynamics, but no analysis of morphological changes induced by seasonal or artifi...

  7. Correlation of an electrical penetration graph waveform with walking by Asian citrus psyllid, Diaphorina citri Kuwayama

    Science.gov (United States)

    Electrical penetration graph (EPG) monitoring is being used to study how feeding behavior of the Asian citrus psyllid (ACP) (Diaphorina citri Kuwayama) changes in response to insecticides, in an effort to improve the efficacy of widespread insecticide treatments against the insect in Florida citrus....

  8. Low incidence of Candidatus Liberibacter asiaticus in Diaphorina citri and its host plant Murraya paniculata

    Science.gov (United States)

    Huanglongbing (HLB) is one of the most devastating diseases of citrus worldwide. Candidatus Liberibacter asiaticus is the prevalent species of three HLB-associated Liberibacter species, which is vectored by the psyllid Diaphorina citri. The vector and the bacteria have host plants outside Citrus, ...

  9. Morphometric comparisons of Diaphorina citri (Hemiptera: Liviidae populations from Iran, USA and Pakistan

    Directory of Open Access Journals (Sweden)

    Mohammadreza Lashkari

    2015-05-01

    Full Text Available The Asian citrus psyllid (ACP, Diaphorina citri Kuwayama (Hemiptera: Liviidae, vector of citrus greening disease pathogen, Huanglongbing (HLB, is considered the most serious pest of citrus in the world. Prior molecular based studies have hypothesized a link between the D. citri in Iran and the USA (Florida. The purpose of this study was to collect morphometric data from D. citri populations from Iran (mtCOI haplotype-1, Florida (mtCOI haplotype-1, and Pakistan (mtCOI haplotype-6, to determine whether different mtCOI haplotypes have a relationship to a specific morphometric variation. 240 samples from 6 ACP populations (Iran—Jiroft, Chabahar; Florida—Ft. Pierce, Palm Beach Gardens, Port St. Lucie; and Pakistan—Punjab were collected for comparison. Measurements of 20 morphological characters were selected, measured and analysed using ANOVA and MANOVA. The results indicate differences among the 6 ACP populations (Wilks’ lambda = 0.0376, F = 7.29, P < 0.0001. The body length (BL, circumanal ring length (CL, antenna length (AL, forewing length (WL and Rs vein length of forewing (RL were the most important characters separating the populations. The cluster analysis showed that the Iran and Florida populations are distinct from each other but separate from the Pakistan population. Thus, three subgroups can be morphologically discriminated within D. citri species in this study, (1 Iran, (2 USA (Florida and (3 Pakistan population. Morphometric comparisons provided further resolution to the mtCOI haplotypes and distinguished the Florida and Iranian populations.

  10. The Influence of Learning on Host Plant Preference in a Significant Phytopathogen Vector, Diaphorina citri.

    Science.gov (United States)

    Stockton, Dara G; Martini, Xavier; Patt, Joseph M; Stelinski, Lukasz L

    2016-01-01

    Although specialist herbivorous insects are guided by innate responses to host plant cues, host plant preference may be influenced by experience and is not dictated by instinct alone. The effect of learning on host plant preference was examined in the Asian citrus psyllid, Diaphorina citri; vector of the causal agent of citrus greening disease or huanglongbing. We investigated: a) whether development on specific host plant species influenced host plant preference in mature D. citri; and b) the extent of associative learning in D. citri in the form of simple and compound conditioning. Learning was measured by cue selection in a 2-choice behavioral assay and compared to naïve controls. Our results showed that learned responses in D. citri are complex and diverse. The developmental host plant species influenced adult host plant preference, with female psyllids preferring the species on which they were reared. However, such preferences were subject to change with the introduction of an alternative host plant within 24-48 hrs, indicating a large degree of experience-dependent response plasticity. Additionally, learning occurred for multiple sensory modalities where novel olfactory and visual environmental cues were associated with the host plant. However, males and females displayed differing discriminatory abilities. In compound conditioning tasks, males exhibited recognition of a compound stimulus alone while females were capable of learning the individual components. These findings suggest D. citri are dynamic animals that demonstrate host plant preference based on developmental and adult experience and can learn to recognize olfactory and visual host plant stimuli in ways that may be sex specific. These experience-based associations are likely used by adults to locate and select suitable host plants for feeding and reproduction and may suggest the need for more tailored lures and traps, which reflect region-specific cultivars or predominate Rutaceae in the area

  11. Antifungal Effect of the Aqueous and Ethanolic Avicennia marina Extracts on Alternaria citri and Penicillium digitatum

    Directory of Open Access Journals (Sweden)

    Behrooz Alizadeh Behbahani

    2016-02-01

    Full Text Available Background Plants have a great potential for producing new drugs of great benefit to mankind. There are many approaches to the search for new biologically active principles in higher plants. Objectives The aim of this study was to determine antifungal effect of the aqueous and ethanolic extracts of Avicennia marina on Penicillium digitatum and Alternaria citri in vitro. Materials and Methods In this experimental study, antimicrobial effects of extract were determined by screening antimicrobial activity and disk agar diffusion test in 20, 40, 60 and 80 mg/mL concentration of the extract against P. digitatum and A. citri. Minimum inhibitory concentration (MIC and minimum fungicidal concentration (MFC were determined by incorporating various concentrations of extracts in Sabouraud dextrose agar (SDA in tubes against P. digitatum and A. citri. The data were analyzed using one way analysis of variance (ANOVA using SPSS-17. Results The results indicate that extracts of A. marina mostly had been effective on P. digitatum and have the least impact on A. citri. The results show that the ethanol extract of mangrove leaf with antimicrobial activity method in 2 mg/mL, were inhibited the growth of P. digitatum and A. citri. In disk agar diffusion test the mentioned extract were shown inhibition effect on pathogen molds growth (P < 0.05. Conclusions Ethanolic extract compared to the aqueous extract was more effective and has a greater inhibition effect. The results of this study showed that the extract of A. marina has antifungal properties that justify their traditional use as medicinal plants.

  12. Insecticidal suppression of Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae) vector of huanglongbing pathogens.

    Science.gov (United States)

    Qureshi, Jawwad A; Kostyk, Barry C; Stansly, Philip A

    2014-01-01

    Diaphorina citri vectors pathogens that cause 'huanglongbing' or citrus greening disease which poses a serious threat to citrus production worldwide. Vector suppression is critical to reduce disease spread. Efficacy is a main concern when choosing an insecticide. Insecticidal treatments of 49 products or 44 active ingredients (a.i) labeled or experimental were field tested between 2005-2013 as foliar sprays (250 treatments, 39 a.i) or soil applications (47 treatments, 9 a.i) to control D. citri in citrus. A combined effect of nymphal and adult suppression in response to sprays of 23 insecticides representing 9 modes of action (MoA) groups and 3 unknown MoA provided more than 90% reduction of adult D. citri over 24-68 days. Observable effects on nymphs were generally of shorter duration due to rapid maturation of flush. However, reduction of 76-100% nymphs or adults over 99-296 days was seen on young trees receiving drenches of the neonicotinoids imidacloprid, thiamethoxam or clothianidin (MoA 4A) and a novel anthranilic diamide, cyantraniliprole (MoA 28). Effective products identified for foliar sprays to control D. citri provide sufficient MoA groups for rotation to delay evolution of insecticide resistance by D. citri and other pests. However, cyantraniliprole is now the only available alternative for rotation with neonicotinoids in soil application to young trees. Sprays of up to eight of the most effective insecticides could be rotated over a year without repetition of any MoA and little or no recourse to neonicotinoids or cyantraniliprole, so important for protection of young trees. Other considerations effecting decisions of what and when to spray include prevalence of huanglongbing, pest pressure, pre-harvest intervals, overall budget, equipment availability, and conservation of beneficial arthropods. Examples of spray programs utilizing broad-spectrum and relatively selective insecticides are provided to improve vector management and may vary depending on

  13. Multimodal cues drive host-plant assessment in Asian citrus psyllid (Diaphorina citri).

    Science.gov (United States)

    Patt, Joseph M; Meikle, William G; Mafra-Neto, Agenor; Sétamou, Mamoudou; Mangan, Robert; Yang, Chenghai; Malik, Nasir; Adamczyk, John J

    2011-12-01

    Asian citrus psyllid (Diaphorina citri) transmits the causal agent of Huanglongbing, a devastating disease of citrus trees. In this study we measured behavioral responses of D. citri to combinations of visual, olfactory, and gustatory stimuli in test arenas. Stimuli were presented to the psyllids in droplets or lines of an emulsified wax formulation in two different arena types in no-choice tests. First, when placed on a colored ring situated halfway between the center and perimeter of a petri dish, D. citri spent more time on yellow versus gray rings; however, this response disappeared when either gray or yellow wax droplets were applied. When the psyllids were presented with droplets scented with terpenes, the response to both scent and color was increased. The addition of a dilute (≍0.1 M) sucrose solution to the wax droplets increased the magnitude of D. citri responses. Next, groups of D. citri were placed on plastic laboratory film covering a sucrose solution, to mimic a leaf surface. Test stimuli were presented via two 'midribs' made from lines of emulsified wax formulation. Probing levels were measured as a function of color saturation and scent composition, and concentration. The test scents were based on qualitatively major volatiles emitted by Murraya paniculata (L.) Jack, Citrus aurantifolia (Christm.) Swingle, and C. sinensis (L.) Osbeck. The highest probing response was observed on the middle concentration (20-μl scent/10 ml wax formulation) of the C. aurantifolia-scented wax lines. Results indicate that there are interactive effects between the different sensory modalities in directing host-plant assessment behavior.

  14. The Influence of Learning on Host Plant Preference in a Significant Phytopathogen Vector, Diaphorina citri.

    Directory of Open Access Journals (Sweden)

    Dara G Stockton

    Full Text Available Although specialist herbivorous insects are guided by innate responses to host plant cues, host plant preference may be influenced by experience and is not dictated by instinct alone. The effect of learning on host plant preference was examined in the Asian citrus psyllid, Diaphorina citri; vector of the causal agent of citrus greening disease or huanglongbing. We investigated: a whether development on specific host plant species influenced host plant preference in mature D. citri; and b the extent of associative learning in D. citri in the form of simple and compound conditioning. Learning was measured by cue selection in a 2-choice behavioral assay and compared to naïve controls. Our results showed that learned responses in D. citri are complex and diverse. The developmental host plant species influenced adult host plant preference, with female psyllids preferring the species on which they were reared. However, such preferences were subject to change with the introduction of an alternative host plant within 24-48 hrs, indicating a large degree of experience-dependent response plasticity. Additionally, learning occurred for multiple sensory modalities where novel olfactory and visual environmental cues were associated with the host plant. However, males and females displayed differing discriminatory abilities. In compound conditioning tasks, males exhibited recognition of a compound stimulus alone while females were capable of learning the individual components. These findings suggest D. citri are dynamic animals that demonstrate host plant preference based on developmental and adult experience and can learn to recognize olfactory and visual host plant stimuli in ways that may be sex specific. These experience-based associations are likely used by adults to locate and select suitable host plants for feeding and reproduction and may suggest the need for more tailored lures and traps, which reflect region-specific cultivars or predominate

  15. Insecticidal suppression of Asian citrus psyllid Diaphorina citri (Hemiptera: Liviidae vector of huanglongbing pathogens.

    Directory of Open Access Journals (Sweden)

    Jawwad A Qureshi

    Full Text Available Diaphorina citri vectors pathogens that cause 'huanglongbing' or citrus greening disease which poses a serious threat to citrus production worldwide. Vector suppression is critical to reduce disease spread. Efficacy is a main concern when choosing an insecticide. Insecticidal treatments of 49 products or 44 active ingredients (a.i labeled or experimental were field tested between 2005-2013 as foliar sprays (250 treatments, 39 a.i or soil applications (47 treatments, 9 a.i to control D. citri in citrus. A combined effect of nymphal and adult suppression in response to sprays of 23 insecticides representing 9 modes of action (MoA groups and 3 unknown MoA provided more than 90% reduction of adult D. citri over 24-68 days. Observable effects on nymphs were generally of shorter duration due to rapid maturation of flush. However, reduction of 76-100% nymphs or adults over 99-296 days was seen on young trees receiving drenches of the neonicotinoids imidacloprid, thiamethoxam or clothianidin (MoA 4A and a novel anthranilic diamide, cyantraniliprole (MoA 28. Effective products identified for foliar sprays to control D. citri provide sufficient MoA groups for rotation to delay evolution of insecticide resistance by D. citri and other pests. However, cyantraniliprole is now the only available alternative for rotation with neonicotinoids in soil application to young trees. Sprays of up to eight of the most effective insecticides could be rotated over a year without repetition of any MoA and little or no recourse to neonicotinoids or cyantraniliprole, so important for protection of young trees. Other considerations effecting decisions of what and when to spray include prevalence of huanglongbing, pest pressure, pre-harvest intervals, overall budget, equipment availability, and conservation of beneficial arthropods. Examples of spray programs utilizing broad-spectrum and relatively selective insecticides are provided to improve vector management and may vary

  16. Expressão gênica diferencial de laranja Pêra Rio (Citrus sinensis (L.) Osbeck) e Lima Ácida 'Galego' (Citrus aurantifolia Swingle) em resposta à infecção por Xanthomonas citri subsp. citri

    OpenAIRE

    Cavallini, Juliana da Silva [UNESP

    2013-01-01

    The citrus agribusiness is very important to the Brazilian economy, but the increase of diseases in the last decade has caused great economic losses to the sector. The citrus canker, caused by the bacterium Xanthomonas citri subsp. citri (Xac), is a serious disease that attacks all citrus species economically important worldwide and there is not an effective method for its control. In this study, RNASeq was used to analyze the transcriptional profiles of two contrasting citrus genotypes regar...

  17. Endosymbiont hunting in the metagenome of Asian citrus psyllid (Diaphorina citri) (7th Annual SFAF Meeting, 2012)

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Surya [Cornell University

    2012-06-01

    Surya Saha on "Endosymbiont hunting in the metagenome of Asian citrus psyllid (Diaphorina citri)" at the 2012 Sequencing, Finishing, Analysis in the Future Meeting held June 5-7, 2012 in Santa Fe, New Mexico.

  18. PV output smoothing with energy storage.

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, Abraham; Schoenwald, David Alan

    2012-03-01

    This report describes an algorithm, implemented in Matlab/Simulink, designed to reduce the variability of photovoltaic (PV) power output by using a battery. The purpose of the battery is to add power to the PV output (or subtract) to smooth out the high frequency components of the PV power that that occur during periods with transient cloud shadows on the PV array. The control system is challenged with the task of reducing short-term PV output variability while avoiding overworking the battery both in terms of capacity and ramp capability. The algorithm proposed by Sandia is purposely very simple to facilitate implementation in a real-time controller. The control structure has two additional inputs to which the battery can respond. For example, the battery could respond to PV variability, load variability or area control error (ACE) or a combination of the three.

  19. Pengaruh Jenis Mangsa dan Suhu pada Perkembangan Menochilus sexmaculatus Fabricius (Coleoptera: Coccinellidae dan Peranannya dalam Pengendalian Diaphorina citri Kuwayama (Hemiptera: Psyllidae

    Directory of Open Access Journals (Sweden)

    Tris Haris Ramadhan

    2008-07-01

    Full Text Available Diaphorina citri Kuwayama (Hemiptera: Psyllidae is the vector of citrus greening (Huanglongbing bacterium and the most serious impediment to citrus culture. Classical biological control of this psyllid vector should contribute to suppress their population. This research was conducted to determine the performance of Menochilus sexmaculatus Fabricius (Coleoptera: Coccinellidae when they were fed with D. citri. The larval performance index of M. sexmaculatus on D. citri compared with Aphis craccivora Koch (Hemiptera: Aphididae diet was 1.3.M. sexmaculatus fed with D. citri had lower fitness than those fed with A. craccivora as shown by longer larval stadium, lower adult dry weight, less number of egg produced and lower percentage of egg hatched. M. sexmaculatus grew best at the temperature of 27oC. Employing the exclusion procedure under field condition,M. sexmaculatus could reduce the population of D. citri up to 90%. These findings showed that theM. sexmaculatus could be a potential predator in reducing D. citri, particularly when the more preferred prey A. craccivora was not present.   Diaphorina citri Kuwayama (Hemiptera: Psyllidae merupakan kelompok Psyllid yang menularkan penyebab penyakit Huanglongbing yang sangat berbahaya pada tanaman jeruk. Pengendalian hayati klasik telah banyak memberikan kontribusi dalam pengendalian di lapangan. Penelitian ini dilakukan untuk melihat penampilan Menochilus sexmaculatus Fabricius (Coleoptera: Coccinellidae dengan pakan D. citri. Indeks penampilan larva M. sexmaculatus dengan pakan D. citri dibandingkan dengan Aphis craccivora Koch (Hemiptera: Aphididae adalah 1,3. M. sexmaculatus yang diberi pakan D. citri menunjukkan penurunan kebugaran dibandingkan jika diberi pakan A. craccivora seperti yang ditunjukkan dengan stadium larva lebih lama, penurunan berat kering serangga dewasa, telur yang dihasilkan lebih sedikit, dan penurunan jumlah telur yang menetas. Menggunakan metode eksklusi pada kondisi

  20. High-efficiency Transformerless PV Inverter Circuits

    OpenAIRE

    Chen, Baifeng

    2015-01-01

    With worldwide growing demand for electric energy, there has been a great interest in exploring photovoltaic (PV) sources. For the PV generation system, the power converter is the most essential part for the efficiency and function performance. In recent years, there have been quite a few new transformerless PV inverters topologies, which eliminate the traditional line frequency transformers to achieve lower cost and higher efficiency, and maintain lower leakage current as well. With an ov...

  1. Green Fluorescent Detection of Fungal Colonization and Endopolygalacturonase Gene Expression in the Interaction of Alternaria citri with Citrus.

    Science.gov (United States)

    Isshiki, A; Ohtani, K; Kyo, M; Yamamoto, H; Akimitsu, K

    2003-07-01

    ABSTRACT Alternaria citri, a postharvest pathogen, produces endopolygalacturonase (endoPG) and causes black rot on citrus fruit. We previously described that an endoPG-disrupted mutant of Alternaria citri was significantly reduced in its ability to macerate plant tissue and cause black rot symptoms on citrus. In order to investigate colonization of citrus fruit tissues by Alternaria citri, pTEFEGFP carrying a green fluorescent protein (GFP) gene was introduced into wild-type Alternaria citri and its endoPG-disrupted mutant (M60). Green fluorescence was observed in spores, germ tubes, appressoria, and infection hyphae of transformants G1 (derived from wild type) and GM4 (derived from M60). Hyphae of G1 but not GM4 vertically penetrated the peel, but the hyphae of both G1 and GM4 spread equally in the juice sac area of citrus fruit. Green fluorescence of Alternaria citri transformant EPG7 carrying a GFP gene under control of the endoPG gene promoter of Alternaria citri was induced by pectin in the peel during the infection stage, but repressed completely in the juice sac area, likely by carbon catabolite repression by sugars in the juice.

  2. Survey of endosymbionts in the Diaphorina citri metagenome and assembly of a Wolbachia wDi draft genome.

    Directory of Open Access Journals (Sweden)

    Surya Saha

    Full Text Available Diaphorina citri (Hemiptera: Psyllidae, the Asian citrus psyllid, is the insect vector of Ca. Liberibacter asiaticus, the causal agent of citrus greening disease. Sequencing of the D. citri metagenome has been initiated to gain better understanding of the biology of this organism and the potential roles of its bacterial endosymbionts. To corroborate candidate endosymbionts previously identified by rDNA amplification, raw reads from the D. citri metagenome sequence were mapped to reference genome sequences. Results of the read mapping provided the most support for Wolbachia and an enteric bacterium most similar to Salmonella. Wolbachia-derived reads were extracted using the complete genome sequences for four Wolbachia strains. Reads were assembled into a draft genome sequence, and the annotation assessed for the presence of features potentially involved in host interaction. Genome alignment with the complete sequences reveals membership of Wolbachia wDi in supergroup B, further supported by phylogenetic analysis of FtsZ. FtsZ and Wsp phylogenies additionally indicate that the Wolbachia strain in the Florida D. citri isolate falls into a sub-clade of supergroup B, distinct from Wolbachia present in Chinese D. citri isolates, supporting the hypothesis that the D. citri introduced into Florida did not originate from China.

  3. P.V. Jensen-Klint

    DEFF Research Database (Denmark)

    Jensen, Thomas Bo

    2006-01-01

    Bogen præsenterer og analyserer P.V. Jensen-Klints samlede arkitekturproduktion samt en mindre del af hans øvrige kunstneriske arbejder. Bogen rummer en grundig biografi om P.V. Jensen-Klints liv og gerning og præsenterer for første gang hans samlede arkitekturproduktion.......Bogen præsenterer og analyserer P.V. Jensen-Klints samlede arkitekturproduktion samt en mindre del af hans øvrige kunstneriske arbejder. Bogen rummer en grundig biografi om P.V. Jensen-Klints liv og gerning og præsenterer for første gang hans samlede arkitekturproduktion....

  4. Electrical PV array reconfiguration strategy for energy extraction improvement in grid-connected PV systems

    OpenAIRE

    2009-01-01

    This paper applies a dynamical electrical array reconfiguration (EAR) strategy on the photovoltaic (PV) generator of a grid-connected PV system based on a plant-oriented configuration, in order to improve its energy production when the operating conditions of the solar panels are different. The EAR strategy is carried out by inserting a controllable switching matrix between the PV generator and the central inverter, which allows the electrical reconnection of the available PV modules. A...

  5. Titers of 'Ca. Liberibacter asiaticus' in Murraya paniculata and Murraya-reared Diaphorina citri Are Much Lower than in Citrus and Citrus-reared Psyllids

    National Research Council Canada - National Science Library

    Walter, Abigail; Duan, Y; Hall, David G

    2012-01-01

    Huanglongbing, one of the most devastating diseases of citrus, is associated with the bacterium 'Candidatus Liberibacter asiaticus' vectored by the Asian citrus psyllid, Diaphorina citri, in North America...

  6. 46 CFR 153.355 - PV venting systems.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false PV venting systems. 153.355 Section 153.355 Shipping... Systems § 153.355 PV venting systems. When Table 1 requires a PV venting system, the cargo tank must have a PV valve in its vent line. The PV valve must be located between the tank and any connection...

  7. 40 CFR 180.1261 - Xanthomonas campestris pv. vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages.

    Science.gov (United States)

    2010-07-01

    ... and Pseudomonas syringae pv. tomato specific Bacteriophages. 180.1261 Section 180.1261 Protection of.... vesicatoria and Pseudomonas syringae pv. tomato specific Bacteriophages. An exemption from the requirement of... syringae pv. tomato specific bacteriophages in or on pepper and tomato. ...

  8. Adiabatic Rearrangement of Hollow PV Towers

    Directory of Open Access Journals (Sweden)

    Eric A Hendricks

    2010-10-01

    Full Text Available Diabatic heating from deep moist convection in the hurricane eyewall produces a towering annular structure of elevated potential vorticity (PV. This structure has been referred to as a hollow PV tower. The sign reversal of the radial gradient of PV satisfies the Charney-Stern necessary condition for combined barotropic-baroclinic instability. For thin enough annular structures, small perturbations grow exponentially, extract energy from the mean flow, and lead to hollow tower breakdown, with significant vortex structural and intensity change. The three-dimensional adiabatic rearrangements of two prototypical hurricane-like hollow PV towers (one thick and one thin are examined in an idealized framework. For both hollow towers, dynamic instability causes air parcels with high PV to be mixed into the eye preferentially at lower levels, where unstable PV wave growth rates are the largest. Little or no mixing is found to occur at upper levels. The mixing at lower and middle levels is most rapid for the breakdown of the thin hollow tower, consistent with previous barotropic results. For both hollow towers, this advective rearrangement of PV affects the tropical cyclone structure and intensity in a number of ways. First, the minimum central pressure and maximum azimuthal mean velocity simultaneously decrease, consistent with previous barotropic results. Secondly, isosurfaces of absolute angular momentum preferentially shift inward at low levels, implying an adiabatic mechanism by which hurricane eyewall tilt can form. Thirdly, a PV bridge, similar to that previously found in full-physics hurricane simulations, develops as a result of mixing at the isentropic levels where unstable PV waves grow most rapidly. Finally, the balanced mass field resulting from the PV rearrangement is warmer in the eye between 900 and 700 hPa. The location of this warming is consistent with observed warm anomalies in the eye, indicating that in certain instances the hurricane

  9. Multifunctionality of PV shells; Multifunktionalitaet von PV-Fassaden

    Energy Technology Data Exchange (ETDEWEB)

    Erban, C. [Saint-Gobain Glass Solar, Aachen (Germany)

    2000-08-01

    Integrated PV systems have come a long way since the construciton of the first solar building shell eight years ago. All technical problems have be solved, and a multitude of solar wall elements are now available that enable architects and planners to design their own customised solar building. [German] Der Einsatz von gebaeudeintegrierter Photovoltaik hat in den nunmehr acht Jahren seit dem Bau der ersten Solarfassade erhebliche Fortschritte gemacht. In technischer Hinsicht ist heute nahezu alles moeglich. Der Umsetzung der einstigen Vision 'Jedem Gebaeude seine Solaranlage' steht heute nichts mehr entgegen, zumal zahlreiche Foerdermoeglichkeiten existieren. Die Vielzahl der Einsatz- und Kombinationsmoeglichkeiten von Solar-Fassadenelementen versetzen Planer und Architekten in die Lage, ihrer individuellen Idee einer gebaeudeintegrierten Solaranlage Gestalt zu geben. (orig.)

  10. PV integration into a CSP plant

    Science.gov (United States)

    Carvajal, Javier López; Barea, Jose M.; Barragan, Jose; Ortega, Carlos

    2017-06-01

    This paper describes a preliminary techno-economic analysis of the integration of a PV plant into an optimized Parabolic Trough Plant in order to reduce the online consumptions and thus, increase the net electricity injected into the grid. The idea is to assess the feasibility of such project and see what configuration would be the optimal. An extra effort has been made in terms of modelling as the analysis has to be done to the integrated CSP + PV plant instead of analyzing them independently. Two different technologies have been considered for the PV plant, fix and one-axis tracking. Additionally three different scenarios have been considered for the CSP plant auxiliary consumptions as they are essential for determining the optimal PV plant (the higher the auxiliary consumption the higher the optimal PV plant). As could be expected, the results for all cases with PV show an improvement in terms of electricity generation and also in terms of LCOE with respect to the CSP plant. Such improvement is slightly higher with tracking technology for this specific study. Although this exercise has been done to an already designed CSP plant (so only the PV plant had to be optimized), the methodology could be applied for the optimization of an integrated CSP + PV plant during the design phase.

  11. Distributed PV Adoption - Sensitivity to Market Factors

    Energy Technology Data Exchange (ETDEWEB)

    Gagnon, Pieter; Sigrin, Ben

    2016-02-01

    NREL staff used the dSolar (distributed solar) model to forecast the adoption of distributed, behind-the-meter PV through the year 2050 for 9 different scenarios. The scenarios varied in their assumptions about a carbon tax, the cost of PV systems in the future, and what credit would be given for excess generation once current net metering policies expire.

  12. Global PV markets and perspectives

    Energy Technology Data Exchange (ETDEWEB)

    Wolfsegger, Cristoph [European Photolvoltaic Industry Association (EPIA), Brussels, Belgium (Belgium)

    2007-06-15

    This presentation mainly talks about the global importance of the PV industry, not only in the environmental sphere but also in the economic sphere. It is firstly given the major information of the European Photovoltaic Industry Association (EPIA), where there can be found the lists of those full member countries that work as: components manufacturers, consulting, and associate members. Then, it is given a briefly explanation about the Alliance for Rural Electrification (ARE), and the reasons why the -PV systems- are almost the panacea to both the energy and the environmental issue. In addition, it is given the most relevant information about how to implement this system in those regions that have not yet implemented it. Besides, there are explained some of the benefits that this system has. It is shortly explained how this system is working in German and it is also shown a comparison chart about the photovoltaic feed-in tariffs. There are shown some graphics and charts having information related to the global markets and the global installations of PV systems and other issues related to them. [Spanish] Esta presentacion habla principalmente acerca de la importancia que hoy en dia tiene la industria fotovoltaica alrededor del mundo, esto no solo ocurre en el ambito ambiental sino tambien en el economico. En la primer parte se muestra la informacion mas importante acerca de la Asociacion Europea de la Industria Fotovoltaica (EPIA por sus siglas en ingles), en donde se encuentran las listas de los paises que son miembros permanentes trabajando como: fabricantes de componentes, asesores y miembros asociados. Enseguida, se da, de manera escueta, una explicacion acerca de la ARE, asi como las razones por las que los sistemas fotovoltaicos son casi la panacea tanto para los problemas ambientales como para los energeticos. Ademas, se explica la informacion mas relevante acerca de como implementar este sistema en aquellas partes del mundo que todavia no lo han realizado

  13. Optimal design of PV and HP system

    DEFF Research Database (Denmark)

    Nepper-Rasmussen, Bjarke Christian; Rasmussen, Theis Bo

    2015-01-01

    electric energy demand of the HP to hours where excess PV power is present. The self-consumption of the PV energy affects the overall net present value (NPV). In this paper, a method which maximizes the NPV by finding the cost-optimal combination of PV, HP and BT sizes, is proposed. Results show...... that the thermal storage with a BT is a better investment than a PV system without HP or no investment. Furthermore, it showed that the optimization model developed in this project is capable of finding the optimal combination of component sizes based on our data....... is described, where the thermal energy is stored in a buffer tank (BT) capable of dispersing heat to either the heating system of a house or a hot water tank, for later use. The thermal storage solution including a BT can increase the self-consumption of residentially produced PV power and thereby shift...

  14. Structural and functional analyses of the putrescine binding protein PotF from Xanthomonas citri

    Energy Technology Data Exchange (ETDEWEB)

    Santana, L.D.F.; Balan, A. [Laboratorio Nacional de Biociencias - LNBIO, Campinas, SP (Brazil)

    2012-07-01

    Full text: The focus of our group is to determinate the role of ABC transporters in the physiology and growth of Xanthomonas citri, a phytopathogenic bacteria that infects citrus plants causing significant losses for the economy. One of the ABC transporters identified in the X. citri genome and that was showed to be active during the infection in Citrus sinensis plants was the putrescine transporter. This transporter consists of two internal membrane proteins PotG and PotH that form a pore, a cytoplasmic protein that gives energy for the transport and the periplasmic-binding protein PotF, which is responsible for the affinity and specificity of the system. Its function is associated to the microbial carcinogenesis, biofilm formation, escape from phagolysosomes, bacteriocin production, toxin activity and protection from oxidative and acid stress. In this work, we show for the first time, the expression, purification, functional and structural analyses of the X. citri PotF protein. The PotF was expressed from Escherichia coli cells strain Arctic, as a 40 kDa soluble protein, after induction of IPTG for twenty four hours at thirteen deg C. Using immobilized metal affinity chromatography for purification, the protein was eluted in the fractions with 10-500 mM of imidazole. To test the folding and cability to bind putrescine, spectroscopic analyses were performed using circular dichroism and intrinsic fluorescence. The data showed that PotF suffers conformational changes in presence of ligands and in different pH, suggesting a possible interaction with the tested ligand. Moreover, based on bioinformatics studies and molecular modeling analyses, we showed that X. citri PotF is highly conserved when compared to orthologs present in other bacteria, including the residues that form the ligand-binding site. The production of PotF in a soluble and stable form will allow us to start the crystallization trials in attempt to solve its structure. (author)

  15. Seasonal Population Dynamics of the Asian Citrus Psyllid, Diaphorina citri Kuwayama in Sarawak

    Directory of Open Access Journals (Sweden)

    Stephen L.C. Teck

    2011-01-01

    Full Text Available Problem statement: Effective control of phytophagous pests requires a thorough understanding of their seasonal population dynamics, dispersion behavior, natural enemy activity and climate. To date, although very little detail information had been published on the ecology of Diaphorina citri. The objective of this investigation was to test through field experiment the hypothesis that the major factors influencing local D. citri populations particularly their seasonal population dynamics in Sarawak are (a flushing cycles, (b climate and (c the impact of the primary parasitoids namely Tamarixia radiata and Diaphorencyrtus aligarhensis. Approach: Seasonal abundance D. citri was studied weekly from March 1998 to December 2000 in the 1-ha citrus honey mandarin (Citrus aurantium L. commercial orchard at Jemukan (1° 33'N, 110° 41'E, Kota Samarahan Division, Southwest Sarawak, in Malaysia. Results: Field studies on citrus trees showed that the D. citri population fluctuates throughout the year on citrus honey mandarin in Sarawak. Generations overlapped but adult and egg population peaks for a short period generally coincided with three annual flushing cycles, in August-September, February-March and June-July between March 1998 and December 2000. Conclusion: Psyllid population levels are positively related to the availability of new shoot flushes. Psyllid populations are adversely affected by weather conditions and parasitoids. Adult psyllid populations increased exponentially during periods of flush growth and migration and dispersal of the adults was also related to flushing cycles. Dispersal and colonization of new trees is greatest in September-October, at the onset of the rainy season.

  16. Novel diagnosis for citrus stubborn disease by detection of a spiroplasma citri-secreted protein.

    Science.gov (United States)

    Shi, Jinxia; Pagliaccia, Deborah; Morgan, Robyn; Qiao, Yongli; Pan, Songqin; Vidalakis, Georgios; Ma, Wenbo

    2014-02-01

    Citrus stubborn disease (CSD), first identified in California, is a widespread bacterial disease found in most arid citrus-producing regions in the United States and the Mediterranean Region. The disease is caused by Spiroplasma citri, an insect-transmitted and phloem-colonizing bacterium. CSD causes significant tree damage resulting in loss of fruit production and quality. Detection of CSD is challenging due to low and fluctuating titer and sporadic distribution of the pathogen in infected trees. In this study, we report the development of a novel diagnostic method for CSD using an S. citri-secreted protein as the detection marker. Microbial pathogens secrete a variety of proteins during infection that can potentially disperse systemically in infected plants with the vascular flow. Therefore, their distribution may not be restricted to the pathogen infection sites and could be used as a biological marker for infection. Using mass spectrometry analysis, we identified a unique secreted protein from S. citri that is highly expressed in the presence of citrus phloem extract. ScCCPP1, an antibody generated against this protein, was able to distinguish S. citri-infected citrus and periwinkle from healthy plants. In addition, the antiserum could be used to detect CSD using a simple direct tissue print assay without the need for sample processing or specialized lab equipment and may be suitable for field surveys. This study provides proof of a novel concept of using pathogen-secreted protein as a marker for diagnosis of a citrus bacterial disease and can probably be applied to other plant diseases.

  17. Biology of the Huanglongbing vector Diaphorina citri (Hemiptera: Liviidae) on different host plants.

    Science.gov (United States)

    Alves, G R; Diniz, A J F; Parra, J R P

    2014-04-01

    Although many studies have been conducted on the development and reproductive potential of Diaphorina citri Kuwayama, 1908 (Hemiptera: Liviidae) in different host species, few have evaluated these parameters on different varieties of the same host species. This study evaluated the influence of five commercial varieties of citrus (Citrus spp. L.)--Hamlin, Natal, Pêra, Ponkan, and Valencia-and orange jasmine [Murraya exotica (L.) Jack] on the development of D. citri. Survival rates for the egg stage were highest on orange jasmine (85.7%) and on Valencia (83.3%). The lowest viability of the nymphal stage was also observed on Hamlin, averaging 57.4%. Values for total viability ranged from 65.9 to 32.6%, and were highest on Valencia. The longest egg-adult development time was on Natal, with a mean of 18.4 d; the shortest total development time was on orange jasmine, with a mean of 17.3 d. Based on the fertility life table, the net reproductive rate (Ro) of D. citri was 2.5 times higher when reared on Valencia than on Hamlin. The other parameters (duration of each generation [T], finite rate of increase [lambda], and innate capacity to increase in number [r(m)]) also demonstrated that Valencia is best suited to this insect. The results obtained for the biological parameters and the fertility life table indicate that Valencia and orange jasmine were the most suitable hosts, whereas Hamlin was least suitable for the development of D. citri. These results provide information for the installation of new citrus groves, especially in the choice of varieties to be planted and the location of different varieties within the groves, with a view toward the management of Huanglongbing or HLB.

  18. Brachygastra mellifica (Hymenoptera: Vespidae): Predation preference and feeding behavior on Diaphorina citri (Hemiptera: Psyllidae) in Mexico

    OpenAIRE

    Reyes-Rosas, M. A.; Loera-Gallardo, J.; López-Arroyo, J. I.; Buck, M.

    2014-01-01

    In previous field studies in Northern Mexico, we found the wasp Brachygastra mellifica (Say 1837) (Hymenoptera: Vespidae) preying voraciously the Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Psyllidae), the vector of the bacteria Ca. Liberibacter spp., the putative agent of Huanglongbing, one of the most devastating citrus disease in the world.   As in Mexico, the ACP management considers the use of pest biological control, the availability of potential agents for the con...

  19. Adjuvants to improve aerial control of the citrus mealybug Planococcus citri (Hemiptera: Pseudococcidae) using entomopathogenic nematodes.

    Science.gov (United States)

    van Niekerk, S; Malan, A P

    2015-03-01

    The citrus mealybug, Planococcus citri, is a highly destructive pest of citrus, occurring only in the aerial parts of plants. Humidity will be one of the key factors to consider when using entomopathogenic nematodes (EPN) as biological control agents. Different adjuvants can be added to suspensions of EPNs, to improve control as a foliar application. An aqueous suspension containing Heterorhabditis zealandica and 0.3% Zeba® significantly increased P. citri mortality by 22% at 80% relative humidity (RH) with a temperature cycle starting at 22°C for 14 h and 11°C for 11 h. The same polymer formulation was tested for Steinernema yirgalemense and mortality of P. citri increased by 21% at 60% RH and by 27% at 80% RH. The addition of Nu-Film-P® and Zeba® to H. zealandica suspensions did not significantly retard application run-off on citrus leaves. The combination of Nu-Film-P® and Zeba®, however, was able to significantly retard sedimentation, increasing the average number of nematodes deposited on 2-cm2 leaf discs by 10 nematodes. In an aqueous suspension, nematodes settle rapidly to the bottom, resulting in an uneven distribution of nematodes. Xanthan gum, at a concentration of 0.2%, was highly effective at retarding sedimentation, with 72% of the initial nematode number still in suspension after 1 h. Zeba®, at a concentration of 0.3%, despite not being as effective as Xanthan gum, nevertheless still retarded sedimentation significantly. This is the first report of the potential of Nu-Film-P® and Zeba® to improve EPN performance against P. citri when used above ground in citrus orchards.

  20. Power of design - the future of building-integrated PV

    Energy Technology Data Exchange (ETDEWEB)

    Abbate, Cinzia [ENEL, Rome (Italy). Officine di Architettura

    2001-04-01

    This paper discusses strategies to make building integrated photovoltaic (PV) systems more acceptable and to allow PV material to compete with conventional construction material. The history of developments in building integration and difficulties encountered by architects wishing to use PV products are explored, and the Dutch Amersfoot project in Utrecht involving a new suburb of 501 house covered with PV panels is described. Questions raised regarding architectural integration of PV systems, and PV systems and the construction market are discussed. The Italian PV programme, financial and political constraints, and the positioning of PV on existing structures are reported.

  1. Involvement of CD4+CD25+ regulatory T cells in the pathogenesis of polycythaemia vera

    Institute of Scientific and Technical Information of China (English)

    ZHAO Wen-bo; LI Ying; LIU Xin; ZHANG Ling-yan; WANG Xin

    2008-01-01

    Background Regulatory T cells (Treg) have been shown to play an important role in the regulation of hematopoietic activity. However, there is no information about the effect of Treg cells in the pathogenesis of polycythaemia vera (PV).Methods In this study, we investigated the percentage and function of Treg cells in the peripheral blood of 21 PV patients and 25 healthy donors. Treg cells were identified and characterized as CD4+CD25+FOXP3+ by flow cytometry.The suppressive activity of CD4+CD25+ Treg cells was assessed by the proliferation and cytokine secretion of the co-cultured CD4+CD25- fractions.Results The results showed that the percentage of Treg cells in the peripheral blood of PV patients significantly increased compared to healthy controls ((10.93±4.02)% vs (5.86±1.99)%, P <0.05). Moreover, the mRNA and protein expression of FOXP3 was higher in CD4+CD25+ Treg cells. Coordinately, when co-cultured with the activated CD4+CD25-cells, the CD4+CD25+ Treg cells showed enhanced suppressive function in PV. Yet, the underlying mechanism for the increased frequency and function of CD4+CD25+ Treg cells is still to be clarified.Conclusion Treg cells expansion might account for the abnormal T cell immunity in PV patients and thus contribute to the pathogenesis of PV.

  2. Efficacy of essential oil of Piper aduncum against nymphs and adults of Diaphorina citri.

    Science.gov (United States)

    Volpe, Haroldo Xl; Fazolin, Murilo; Garcia, Rafael B; Magnani, Rodrigo F; Barbosa, José Carlos; Miranda, Marcelo P

    2016-06-01

    Insecticide application is the main way to control Diaphorina citri. However, it causes environmental contamination, has a negative impact on beneficial organisms and leads to psyllid resistance. The essential oil of Piper aduncum has low toxicity towards the environment and contains dillapiol, which has proven to be effective against several crop pests. Here, we studied its efficacy against nymphs and adults of D. citri under laboratory conditions. Oils with three concentrations of dillapiol (69.3, 79.9 and 85.4%) at 0.5, 0.75 and 1.0% dilutions plus 0.025% adjuvant were tested. All treatments caused 90-100% mortality in nymphs. Topical treatments with oil containing 79.9 and 85.4% dillapiol at 0.75% and 1% dilutions were effective (mortality ≥80%) in adults. However, the essential oil showed no residual activity against adults (mortality ≤30%). Dillapiol-rich oil is a promising compound for D. citri control. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  3. Resistance Management for Asian Citrus Psyllid, Diaphorina citri Kuwayama, in Florida

    Directory of Open Access Journals (Sweden)

    Xue Dong Chen

    2017-09-01

    Full Text Available The Asian citrus psyllid, Diaphorina citri Kuwayma, is one of the most important pests in citrus production. The objective of this study was to evaluate D. citri resistance management with three insecticide rotations and compare them with no rotation and an untreated check. The different insecticides (modes of action tested were: dimethoate, imidacloprid, diflubenzuron, abamectin 3% + thiamethoxam 13.9%, and fenpropathrin. Eggs, nymph, and adult psyllids were counted weekly. Five insecticide applications were made in 2016. Insecticide susceptibility was determined by direct comparison with a laboratory susceptible population and field populations before and after all treatments were applied. Rankings of eggs, nymphs, and adults counted in treated plots were significantly lower than in the untreated control plots after each application. Initially, the resistance ratio (RR50 for each rotation model, as compared with laboratory susceptible strain and the field population before application, was less than 5.76 and 4.31, respectively. However, after five applications with dimethoate, the RR50 using the laboratory and pre-treatment field populations was 42.34 and 34.74, respectively. Our results indicate that effectively rotating modes of action can delay and/or prevent development of insecticide resistance in populations of D. citri.

  4. Molecular Effects of Irradiation (Cobalt-60 on the Control of Panonychus citri (Acari: Tetranychidae

    Directory of Open Access Journals (Sweden)

    Ke Zhang

    2015-11-01

    Full Text Available The effective dose of irradiation to control pest mites in quarantine has been studied extensively, but the molecular mechanisms underlying the effects of the irradiation on mites are largely unknown. In this study, exposure to 400 Gy of γ rays had significant (p < 0.05 effects on the adult survival, fecundity and egg viability of Panonychus citri. The irradiation caused the degradation of the DNA of P. citri adults and damaged the plasma membrane system of the egg, which led to condensed nucleoli and gathered yolk. Additionally, the transcriptomes and gene expression profiles between irradiated and non-irradiated mites were compared, and three digital gene expression libraries were assembled and analyzed. The differentially expressed genes were putatively involved in apoptosis, cell death and the cell cycle. Finally, the expression profiles of some related genes were studied using quantitative real-time PCR. Our study provides valuable information on the changes in the transcriptome of irradiated P. citri, which will facilitate a better understanding of the molecular mechanisms that cause the sterility induced by irradiation.

  5. Sequencing and annotation of the Wolbachia endosymbiont of Diaphorina citri by the CG-HLB genome resources group reveals candidate sources of interaction with the insect host

    Science.gov (United States)

    Diaphorina citri (Hemiptera: Psyllidae), the Asian citrus psyllid, is the vector of Ca. Liberibacter asiaticus, the causal agent of huanglongbing. The D. citri metagenome has been completed to gain a better understanding of the biology of this organism and the potential roles of other psyllid bacter...

  6. Xanthomonas citri subsp. citri surface proteome by 2D-DIGE: Ferric enterobactin receptor and other outer membrane proteins potentially involved in citric host interaction.

    Science.gov (United States)

    Carnielli, Carolina Moretto; Artier, Juliana; de Oliveira, Julio Cezar Franco; Novo-Mansur, Maria Teresa Marques

    2017-01-16

    Xanthomonas citri subsp. citri (XAC) is the causative agent of citrus canker, a disease of great economic impact around the world. Understanding the role of proteins on XAC cellular surface can provide new insights on pathogen-plant interaction. Surface proteome was performed in XAC grown in vivo (infectious) and in vitro (non-infectious) conditions, by labeling intact cells followed by cellular lysis and direct 2D-DIGE analysis. Seventy-nine differential spots were analyzed by mass spectrometry. Highest relative abundance for in vivo condition was observed for spots containing DnaK protein, 60kDa chaperonin, conserved hypothetical proteins, malate dehydrogenase, phosphomannose isomerase, and ferric enterobactin receptors. Elongation factor Tu, OmpA-related proteins, Oar proteins and some Ton-B dependent receptors were found in spots decreased in vivo. Some proteins identified on XAC's surface in infectious condition and predicted to be cytoplasmic, such as DnaK and 60KDa chaperonin, have also been previously found at cellular surface in other microorganisms. This is the first study on XAC surface proteome and results point to mediation of molecular chaperones in XAC-citrus interaction. The approach utilized here can be applied to other pathogen-host interaction systems and help to achieve new insights in bacterial pathogenicity toward promising targets of biotechnological interest.

  7. Potential of South African entomopathogenic nematodes (Heterorhabditidae and Steinernematidae) for control of the citrus mealybug, Planococcus citri (Pseudococcidae).

    Science.gov (United States)

    van Niekerk, Sonnica; Malan, Antoinette P

    2012-10-01

    Planococcus citri, the citrus mealybug, is the most important species of mealybug known to infest citrus in South Africa. Various laboratory bioassays were conducted to determine the potential of entomopathogenic nematodes to control P. citri. Adult female P. citri were screened for susceptibility to six indigenous nematode species. P. citri was found to be most susceptible to Steinernema yirgalemense and Heterorhabditis zealandica, causing 97% and 91% mortality, respectively. The development of nematodes after infecting adult female P. citri showed both H. zealandica and S. yirgalemense were able to complete their life cycles inside the host. Further bioassays illustrated a linear relationship between mealybug mortality and the concentration of nematodes applied, with the highest level of control using a concentration of 80 infective juveniles (IJs)/insect. As nematodes would be used as an above-ground application to control P. citri in citrus orchards, available water is a major limiting factor. Insecticidal activity proved to be dependent on the available surface moisture after nematode application. The water activity (a(w)) bioassay indicated that S. yirgalemense to be two times more tolerant to lower levels of free water, with a(w50)=0.96 and a(w90)=0.99, compared to H. zealandica with a(w50)=0.98 and a(w)90=1.0. After application, nematodes have a limited time frame in which to locate and infect hosts, as the level of available free water gradually decreases, as trees dry out. S. yirgalemense proved able to locate and infect P. citri quicker than H. zealandica. Nematode activity was not significantly affected when exposed to 15°C, 20°C and 25°C. IJs were able to infect P. citri at an exposure time as short as half an hour. Results also showed that the first 2-4h post application is the most decisive time for establishing successful infection of mealybugs. This is the first report on the potential use of nematodes for the control of P. citri.

  8. Geographic distribution of habitat, development, and population growth rates of the Asian citrus psyllid, Diaphorina citri, in Mexico.

    Science.gov (United States)

    López-Collado, José; Isabel López-Arroyo, J; Robles-García, Pedro L; Márquez-Santos, Magdalena

    2013-01-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is an introduced pest in Mexico and a vector of huanglongbing, a lethal citrus disease. Estimations of the habitat distribution and population growth rates of D. citri are required to establish regional and areawide management strategies and can be used as a pest risk analysis tools. In this study, the habitat distribution of D. citri in Mexico was computed with MaxEnt, an inductive, machine-learning program that uses bioclimatic layers and point location data. Geographic distributions of development and population growth rates were determined by fitting a temperature-dependent, nonlinear model and projecting the rates over the target area, using the annual mean temperature as the predictor variable. The results showed that the most suitable regions for habitat of D. citri comprise the Gulf of Mexico states, Yucatán Peninsula, and areas scattered throughout the Pacific coastal states. Less suitable areas occurred in northern and central states. The most important predictor variables were related to temperature. Development and growth rates had a distribution wider than habitat, reaching some of the northern states of México. Habitat, development, and population growth rates were correlated to each other and with the citrus producing area. These relationships indicated that citrus producing states are within the most suitable regions for the occurrence, development, and population growth of D. citri, therefore increasing the risk of huanglongbing dispersion.

  9. Analyses of Numerical Responses and Main Life Parameters for Determining the Suppression of Amblyseius cucumeris on Panonychus citri

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yan-xuan; LIN Jian-zhen; JI Jie; CHEN Xie; KANG Yu-mei

    2005-01-01

    In this paper, the numeral response and main parameters of experimental population life table were analyzed for determiningthe suppressing ability of Amblyseius cucumeris on Panonychus citri. The result showed that: (1) Under 21-31 ℃ and 1-9 prey densities/leaf fragment condition, the prey consumptions ofA. cucumeris increased with the temperature or prey density; (2) In 1:3 predator-prey ratio treatment, the suppression ofP. citri (Ro=34.0053; T=19.4369; t=3.8204) was rather weak, it was enhanced as the ratio over 5:30, and the populations ofP. citri in these treatments can be fully controlled within 4-5 days; (3) Under 25±1℃, 80-85% RH and 15L: 9D illumination conditions, the net reproductive rate, mean generation duration and the time for population double increase ofP. citri (Ro=34.0053; T=19.4369; t=3.8204) were higher than those ofA. cucumeris (Ro=21.8750; T=16.8943; t=3.7954). While the intrinsic rate of increase and finite rate of increase of the former (rm=0.1814; λ= 1.1989) were lower than those of the latter (rm=0.1826; λ= 1.2004). These results indicated that A. cucumeris is a desirable bio-control agent to suppress P. citri at lower population stage in citrus orchard.

  10. Expression patterns of genes involved in the defense and stress response of Spiroplasma citri infected Madagascar Periwinkle Catharanthus roseus.

    Science.gov (United States)

    Nejat, Naghmeh; Vadamalai, Ganesan; Dickinson, Matthew

    2012-01-01

    Madagascar periwinkle is an ornamental and a medicinal plant, and is also an indicator plant that is highly susceptible to phytoplasma and spiroplasma infections from different crops. Periwinkle lethal yellows, caused by Spiroplasma citri, is one of the most devastating diseases of periwinkle. The response of plants to S. citri infection is very little known at the transcriptome level. In this study, quantitative real-time PCR (RT-qPCR) was used to investigate the expression levels of four selected genes involved in defense and stress responses in naturally and experimentally Spiroplasma citri infected periwinkles. Strictosidine β-glucosidase involved in terpenoid indole alkaloids (TIAs) biosynthesis pathway showed significant upregulation in experimentally and naturally infected periwinkles. The transcript level of extensin increased in leaves of periwinkles experimentally infected by S. citri in comparison to healthy ones. A similar level of heat shock protein 90 and metallothionein expression was observed in healthy, naturally and experimentally spiroplasma-diseased periwinkles. Overexpression of Strictosidine β-glucosidase demonstrates the potential utility of this gene as a host biomarker to increase the fidelity of S. citri detection and can also be used in breeding programs to develop stable disease-resistance varieties.

  11. Expression Patterns of Genes Involved in the Defense and Stress Response of Spiroplasma citri Infected Madagascar Periwinkle Catharanthus roseus

    Directory of Open Access Journals (Sweden)

    Naghmeh Nejat

    2012-02-01

    Full Text Available Madagascar periwinkle is an ornamental and a medicinal plant, and is also an indicator plant that is highly susceptible to phytoplasma and spiroplasma infections from different crops. Periwinkle lethal yellows, caused by Spiroplasma citri, is one of the most devastating diseases of periwinkle. The response of plants to S. citri infection is very little known at the transcriptome level. In this study, quantitative real-time PCR (RT-qPCR was used to investigate the expression levels of four selected genes involved in defense and stress responses in naturally and experimentally Spiroplasma citri infected periwinkles. Strictosidine β-glucosidase involved in terpenoid indole alkaloids (TIAs biosynthesis pathway showed significant upregulation in experimentally and naturally infected periwinkles. The transcript level of extensin increased in leaves of periwinkles experimentally infected by S. citri in comparison to healthy ones. A similar level of heat shock protein 90 and metallothionein expression was observed in healthy, naturally and experimentally spiroplasma-diseased periwinkles. Overexpression of Strictosidine β-glucosidase demonstrates the potential utility of this gene as a host biomarker to increase the fidelity of S. citri detection and can also be used in breeding programs to develop stable disease-resistance varieties.

  12. The effects of host, geographic origin, and gender on the thermal requirements of Diaphorina citri (Hemiptera: Psyllidae).

    Science.gov (United States)

    Nava, Dori E; Gomez-Torres, Mariuxi L; Rodrigues, Marjorie D; Bento, José M S; Haddad, Marinéia L; Parra, José R P

    2010-04-01

    Diaphorina citri Kuwayama (Hemiptera: Psyllidae) is the vector of the bacteria that causes citrus greening and is considered one of the world's most important citrus diseases. We examined how host, geographic region, and gender affect the thermal requirements of D. citri. The insects were reared in climatic chambers at constant temperatures of 18, 20, 22, 25, 28, 30, and 32 +/- 1 degrees C, 70 +/- 10% RH, and a 14 h photophase. Host plants for D. citri included orange (Citrus sinensis [Rutaceae]) varieties Pêra and Natal, the rootstock, Rungpur lime (C. limonia [Rutaceae]) and the natural host, Orange jessamine (Murraya paniculata [Rutaceae]). To study the influence of geographic origin on thermal requirements, we studied D. citri populations from Piracicaba, SP (warmer region) and Itapetininga, SP (cooler region). The duration and survival of the development stages and the duration of the total development (egg-adult) did not differ significantly on the different hosts, but it did vary with temperature. Nymphs of D. citri created on the different hosts have the same thermal requirements. The thermal requirements for this species collected from the two climate regions were identical; males and females also had the same thermal requirements.

  13. Multifunctional a-Si PV systems

    Energy Technology Data Exchange (ETDEWEB)

    Peippo, K.; Lund, P.; Vartiainen, E. [Helsinki Univ. of Technology, Otaniemi (Finland). Advanced Energy Systems

    1998-10-01

    The optimal use of the various forms of solar energy (passive, active, daylighting, photovoltaics) in buildings calls for an optimal integration of the technologies. As energy conservation potential in space heating may soon be exhausted, electricity efficiency and on-site generation will play an increasing role in energy-conscious building design. There, dispersed PV systems integrated into buildings show a significant market potential, due to a number of benefits: no extra land area is required, PV-array may replace conventional cladding materials and become a building element. Moreover, the produced PV-electricity is more valuable for the building owner than for an electric utility

  14. Establishment of EMA-PCR detection method of viable cells of Xanthomonas citri subsp.citri%柑橘溃疡病菌EMA-PCR快速活体检测技术的建立

    Institute of Scientific and Technical Information of China (English)

    熊书; 王中康; 卢小林; 殷幼平

    2013-01-01

    传统PCR方法不能诊断柑橘溃疡病菌(Xanthomonas citri subsp.citri Gabriel)的死活状态,往往导致假阳性检测结果.本研究将特异性核酸染料叠氮溴化乙锭(ethidium monoazide bromide,EMA)与PCR技术结合,旨在建立柑橘溃疡病活菌的快速检测技术.根据柑橘溃疡病菌独有的保守蛋白基因设计特异性引物扩增出278 bp的靶带,PCR反应的检测下限为25个细胞/25 μL或2.75 pg/25 μL.EMA-PCR结果表明:当卤钨灯曝光时间1 min,EMA终浓度为1.0 mg/L时,能有效抑制1.0×108 cfu/mL死菌的扩增;当EMA的浓度小于30 mg/L时,EMA对上述相同浓度活菌靶基因的扩增没有明显的抑制.EMA-PCR对死活混合菌的扩增表明,活菌数在6.875×101~6.875×105 cfu/PCR范围时,荧光强度与混合体系中活菌的对数值有线性关系.基于以上建立的EMA-PCR活体检测技术,对疑似带病柑橘材料进行检测,结果发现能降低柑橘溃疡病菌检测过程中的假阳性,有望为柑橘溃疡病的检疫检验提供更科学的技术手段.%Conventional PCR method can not distinguish live cells from dead cells of Xanthononas citri subsp.citri Gabriel,and false positives results can easily be obtained in detection process.Ethidium monoazide bromide (EMA) can selectively inhibit PCR amplification of DNA from dead cells.Therefore,in this study,EMA was combined with PCR to detect viable cells of X.citri subsp.citri.Firstly,primers (Xcc R/Xcc F) specific to X.citri subsp.citri were designed to amplify a 278 bp fragment.The minimum limit of detection was 25 cells/25 μL PCR volume or 2.75 pg/25 μ L PCR volume.The results of EMA-PCR showed that the optimized light exposure time was at least 1 min,allowing crosslinking of DNA by the EMA in dead cells and photolysing the free EMA in solution.The minimum amount of EMA to completely inhibit the PCR amplification of DNA derived from heat-killed cells was 1.0 mg/L.EMA less than 30 mg/L did not inhibit the PCR amplification

  15. Using a nonparametric PV model to forecast AC power output of PV plants

    OpenAIRE

    Almeida, Marcelo Pinho; Perpiñan Lamigueiro, Oscar; Narvarte Fernández, Luis

    2015-01-01

    In this paper, a methodology using a nonparametric model is used to forecast AC power output of PV plants using as inputs several forecasts of meteorological variables from a Numerical Weather Prediction (NWP) model and actual AC power measurements of PV plants. The methodology was built upon the R environment and uses Quantile Regression Forests as machine learning tool to forecast the AC power with a confidence interval. Real data from five PV plants was used to validate the methodology, an...

  16. The Pathogenesis of Autism

    OpenAIRE

    Watts, Timothy John

    2008-01-01

    Autism is well known as a complex developmental disorder with a seemingly confusing and uncertain pathogenesis. The definitive mechanisms that promote autism are poorly understood and mostly unknown, yet available theories do appear to focus on the disruption of normal cerebral development and its subsequent implications on the functional brain unit. This mini-review aims solely to discuss and evaluate the most prominent current theories regarding the pathogenesis of autism. The main conclusi...

  17. A Possible Role for CD8+ T Lymphocytes in the Cell-Mediated Pathogenesis of Pemphigus Vulgaris

    Directory of Open Access Journals (Sweden)

    Federica Giurdanella

    2013-01-01

    Full Text Available Pemphigus vulgaris (PV is an autoimmune blistering disease whose pathogenesis involves both humoral and cell-mediated immune response. Though the pathogenetic role of autoantibodies directed against desmoglein 3 is certain, a number of other factors have been suggested to determine acantholysis in PV. In this study we examined the possible role of CD8+ T cells in the development of acantholysis by a passive transfer of PV autoantibodies using CD8 deficient mice, and we also studied the inflammatory infiltrate of PV skin lesions by immunohistochemical staining. The results of the immunohistochemical staining to study the expression of CD3, CD4, and CD8 in PV skin lesions showed that CD4+ are more expressed than CD8+ in the inflammatory infiltrate of PV lesions, confirming the data of the previous literature. The passive transfer study showed a lower incidence of pemphigus in the group of CD8 deficient mice compared to the control one of wild-type mice. These results suggest that CD8+ T cells may play a role in the pathogenesis of PV, perhaps through the Fas/FasL pathway.

  18. A Practical Optimization Method for Designing Large PV Plants

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Koutroulis, E.; Eyigun, S.

    2011-01-01

    Nowadays Photovoltaic (PV) plants have multi MW sizes, the biggest plants reaching tens of MW of capacity. Such large-scale PV plants are made up of several thousands of PV panels, each panel being in the range of 150-350W. This means that the design of a Large PV power plant is a big challenge...

  19. Rating PV Power and Energy: Cell, Module, and System Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Emery, Keith

    2016-06-02

    A summary of key points related to research-level measurements of current vs. voltage measurement theory including basic PV operation, equivalent circuit, and concept of spectral error; PV power performance including PV irradiance sensors, simulators and commercial and generic I-V systems; PV measurement artifacts, intercomparisons, and alternative rating methods.

  20. Distributed PV Adoption in Maine Through 2021

    Energy Technology Data Exchange (ETDEWEB)

    Gagnon, Pieter; Sigrin, Ben

    2015-11-06

    NREL has used its dSolar (distributed solar) model to generate low-medium-high estimates of distributed PV adoption in Maine through 2021. This presentation gives a high-level overview of the model and modeling results.

  1. Leakage current measurement in transformerless PV inverters

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Sera, Dezso; Mathe, Laszlo

    2012-01-01

    to be used in commercial PV inverters for the measurement of leakage and fault ground currents. The German VDE0126–1–1 standard gives the limit for fault and leakage ground currents and all grid connected PV inverters have to comply with these limits and disconnect from the grid in case of a fault.......Photovoltaic (PV) installations have seen a huge increase during the last couple of years. Transformerless PV inverters are gaining more share of the total inverter market, due to their high conversion efficiency, small weight and size. Nevertheless safety should have an important role in case...... of these tranformerless systems, due to the missing galvanic isolation. Leakage and fault current measurement is a key issue for these inverter topologies to be able to comply with the required safety standards. This article presents the test results of two different current measurement sensors that were suggested...

  2. Transformerless PV inverters. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Borup, U.

    2009-12-15

    Since the start of the project the market for grid connected PV inverters have developed further. When the project started three - phase inverter were only available in high power systems. The technology developed within this project will enable three phase technology also to be implemented in string inverters for system down to 10 kW. We expect this to be very attractive due to the increased demand for symmetrical feed-in to the grid. The project relevance is therefore high and the sector continues to develop very much driven by technology. Especially the inverter technology is getting a lot of focus. The inverter systems are expected to take a much larger role in supporting the electrical grid in the future. The technology platform developed within the project is prepared to be extended with these utility functionalities. The main results of the project were: 1) A new technology concept for transformer-less inverters has been demonstrated with a number of prototypes. 2) Efficiency above 97,7% has been proven. 3) Efficiency and Maximum power point tracking has been optimized to ensure that almost all energy produced of the panels is transferred to the grid. 4) The platform is developed with a very fast control board, which enables extended functionality as demanding grid supporting functions in the future. Details about cost price and details about the control loop implementation is excluded from the report due to the competitive situation for Danfoss Solar Inverters A/S. (LN)

  3. Evaluation of efficacy of 18 strains of entomopathogenic nematodes (Rhabditida) against Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) under laboratory conditions.

    Science.gov (United States)

    Barbosa Negrisoli, Carla Ruth de Carvalho; Negrisoli Júnior, Aldomario Santo; Botton, Marcos; Garcia, Mauro Silveira; Bernardi, Daniel

    2013-07-01

    Planococcus citri (Risso, 1813) (Hemiptera: Pseudococcidae) is an important plant virus vector in grapevine crops in Brazil and other countries. The mealybug grows in roots and leaves of the grapes. Entomopathogenic nematodes (EPNs) are efficient control agents against insects associated to the soil and could be applied with the same equipment used for chemical insecticides. The aim of this study was to select effective EPNs for controlling P. citri females in laboratory conditions (25±1°C, UR 60±10%). We tested 17 native [Steinernema rarum (6 strains), Steinernema glaseri, Steinernema feltiae, Steinernema riobrave, Steinernema sp., Heterorhabditis bacteriophora (7 strains)] and only one exotic strain (Steinernema carpocapsae ALL). The bioassays were done on Petri dishes infested with females of P. citri, which were sprayed with EPNs juveniles. The strain with larger pathogenicity and virulence in laboratory was H. bacteriophora RS33 (from 69.0% to 92.2% of mortality), native of Rio Grande do Sul.

  4. Essential Oil Variation from Twenty Two Genotypes of Citrus in Brazil-Chemometric Approach and Repellency Against Diaphorina citri Kuwayama.

    Science.gov (United States)

    Andrade, Moacir Dos Santos; Ribeiro, Leandro do Prado; Borgoni, Paulo Cesar; Silva, Maria Fátima das Graças Fernandes da; Forim, Moacir Rossi; Fernandes, João Batista; Vieira, Paulo Cezar; Vendramin, José Djair; Machado, Marcos Antônio

    2016-06-22

    The chemical composition of volatile oils from 22 genotypes of Citrus and related genera was poorly differentiated, but chemometric techniques have clarified the relationships between the 22 genotypes, and allowed us to understand their resistance to D. citri. The most convincing similarities include the synthesis of (Z)-β-ocimene and (E)-caryophyllene for all 11 genotypes of group A. Genotypes of group B are not uniformly characterized by essential oil compounds. When stimulated with odor sources of 22 genotypes in a Y-tube olfactometer D. citri preferentially entered the arm containing the volatile oils of Murraya paniculata, confirming orange jasmine as its best host. C. reticulata × C. sinensis was the least preferred genotype, and is characterized by the presence of phytol, (Z)-β-ocimene, and β-elemene, which were not found in the most preferred genotype. We speculate that these three compounds may act as a repellent, making these oils less attractive to D. citri.

  5. Addressing firefighter safety around solar PV systems

    Energy Technology Data Exchange (ETDEWEB)

    Harris, B. [Sustainable Energy Technologies, Calgary, AB (Canada)

    2010-11-15

    The article discussed new considerations for installing photovoltaic (PV) systems that address the needs of fire service personnel. The presence of a PV system presents a multitude of dangers for firefighters, including electrical shock, the inhalation of toxic gases from being unable to cut a hole through the roof, falling debris and flying glass, and dead loading on a compromised structure and tripping on conduits. Mapping systems should be modified so that buildings with PV systems are identified for first responders, including firefighters who should learn that solar modules present an electrical hazard during the day but not at night; covering PV modules with foam or salvage covers may not shut the system down to a safe level; it takes a few moments for the power in PV modules to reduce to zero; and PV modules or conduit should never be cut, broke, chopped, or walked upon. The California Department of Forestry and Fire Protection recommends creating pathways and allowing easier access to the roof by setting the modules back from roof edges, creating a structurally sound pathway for firefighters to walk on and space to cut ventilation holes. However, the setback rule makes the economics of solar installation less viable for residential applications. The technological innovations aimed at addressing system safety all focus on limiting firefighter contact with live electrical components to within the extra-low-voltage (ELV) band. Some of the inverters on the market that support ELV system architecture were described. 1 fig.

  6. Updating Technical Screens for PV Interconnection: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Coddington, M.; Ellis, A.; Lynn, K.; Razon, A.; Key, T.; Kroposki, B.; Mather, B.; Hill, R.; Nicole, K.; Smith, J.

    2012-08-01

    Solar photovoltaics (PV) is the dominant type of distributed generation (DG) technology interconnected to electric distribution systems in the United States, and deployment of PV systems continues to increase rapidly. Considering the rapid growth and widespread deployment of PV systems in United States electric distribution grids, it is important that interconnection procedures be as streamlined as possible to avoid unnecessary interconnection studies, costs, and delays. Because many PV interconnection applications involve high penetration scenarios, the process needs to allow for a sufficiently rigorous technical evaluation to identify and address possible system impacts. Existing interconnection procedures are designed to balance the need for efficiency and technical rigor for all DG. However, there is an implicit expectation that those procedures will be updated over time in order to remain relevant with respect to evolving standards, technology, and practical experience. Modifications to interconnection screens and procedures must focus on maintaining or improving safety and reliability, as well as accurately allocating costs and improving expediency of the interconnection process. This paper evaluates the origins and usefulness of the capacity penetration screen, offers potential short-term solutions which could effectively allow fast-track interconnection to many PV system applications, and considers longer-term solutions for increasing PV deployment levels in a safe and reliable manner while reducing or eliminating the emphasis on the penetration screen.

  7. Protein interaction networks at the host–microbe interface in Diaphorina citri, the insect vector of the citrus greening pathogen

    Science.gov (United States)

    Chavez, J. D.; Johnson, R.; Hosseinzadeh, S.; Mahoney, J. E.; Mohr, J. P.; Robison, F.; Zhong, X.; Hall, D. G.; MacCoss, M.; Bruce, J.; Cilia, M.

    2017-01-01

    The Asian citrus psyllid (Diaphorina citri) is the insect vector responsible for the worldwide spread of ‘Candidatus Liberibacter asiaticus’ (CLas), the bacterial pathogen associated with citrus greening disease. Developmental changes in the insect vector impact pathogen transmission, such that D. citri transmission of CLas is more efficient when bacteria are acquired by nymphs when compared with adults. We hypothesize that expression changes in the D. citri immune system and commensal microbiota occur during development and regulate vector competency. In support of this hypothesis, more proteins, with greater fold changes, were differentially expressed in response to CLas in adults when compared with nymphs, including insect proteins involved in bacterial adhesion and immunity. Compared with nymphs, adult insects had a higher titre of CLas and the bacterial endosymbionts Wolbachia, Profftella and Carsonella. All Wolbachia and Profftella proteins differentially expressed between nymphs and adults are upregulated in adults, while most differentially expressed Carsonella proteins are upregulated in nymphs. Discovery of protein interaction networks has broad applicability to the study of host–microbe relationships. Using protein interaction reporter technology, a D. citri haemocyanin protein highly upregulated in response to CLas was found to physically interact with the CLas coenzyme A (CoA) biosynthesis enzyme phosphopantothenoylcysteine synthetase/decarboxylase. CLas pantothenate kinase, which catalyses the rate-limiting step of CoA biosynthesis, was found to interact with a D. citri myosin protein. Two Carsonella enzymes involved in histidine and tryptophan biosynthesis were found to physically interact with D. citri proteins. These co-evolved protein interaction networks at the host–microbe interface are highly specific targets for controlling the insect vector responsible for the spread of citrus greening. PMID:28386418

  8. Desenvolvimento de Planococcus citri (Risso, 1813 (Hemiptera: Pseudococcidae em cafeeiros = Development of Planococcus citri (Risso, 1813 (Hemiptera: Pseudococcidae in coffee trees

    Directory of Open Access Journals (Sweden)

    Lenira Viana Costa Santa-Cecília

    2009-01-01

    Full Text Available A cochonilha Planococcus citri (Risso, 1813 suga a seiva dos botões florais e frutos do cafeeiro, atacando as rosetas desde a floração até a colheita. Embora seja relatada há alguns anos na cafeicultura, são escassas as informações sobre o desenvolvimento dessacochonilha em cafeeiros. Assim, o presente trabalho teve por objetivos avaliar alguns aspectos biológicos da fase ninfal de P. citri em plantas de café. Ovos dessa cochonilha foram retirados de uma criação em laboratório, isolados em placas de Petri contendo discos foliares de Coffea arabica L., das cultivares Acaiá Cerrado, Mundo Novo e Catuaí Vermelho e de C. canephora Pierre & Froenher, cultivar Apoatã. As placas foram mantidas em câmara climatizada a 25 ± 1°C, 70 ± 10% de umidade relativa e 12h de fotofase. Constatou-se que a cultivar Catuaí Vermelho foi a que proporcionou maior duração do período ninfal das fêmeas, porém, não foram constatadas diferenças na mortalidade. Essa cochonilha se desenvolveu satisfatoriamente em todas as cultivares de café estudadas e os resultados não mostraram diferenças claras de susceptibilidade.The citrus mealybug Planococcus citri (Risso, 1813 feeds mainly on flowers and fruits of coffee plants from blooming until harvest. Little is known about its development in coffee although its occurrence is already known for several years. This work aims to study the nymph development of this mealybug in coffee plants.Eggs were isolated from a stock culture kept in laboratory and placed inside Petri dishes containing leaf sections in agar. The tested cultivars were Acaia Cerrado, Mundo Novo, Catuai Vermelho (Coffea arabica and Apoatã (C. canephora. Insects were kept in a climatizedchamber at 25ºC, 70 ± 10% humidity and 12-hour photophase. The longest development period in females was obtained in cultivar Catuai Vermelho. No differences in mortality were found among cultivars. Mealybugs developed in all cultivars and the results

  9. Susceptibilidad de Diaphorina citri Kuwayama (Hemíptera : Liviidae) a insecticidas en Veracruz, México.

    OpenAIRE

    García Méndez, Víctor Hugo

    2013-01-01

    El uso racional de insecticidas requiere una evaluación previa de la efectividad de los productos para evitar aplicaciones inefectivas o el desarrollo de resistencia. El Psílido Asiático de los Cítricos (PAC), Diaphorina citri es vector del Huanglongbing y requiere estrategias de manejo regional de la resistencia. El objetivo de la investigación fue definir las líneas base de manejo de la resistencia y determinar la susceptibilidad de D. citri a insecticidas convencionales de uso común en aé...

  10. The abundant extrachromosomal DNA content of the Spiroplasma citri GII3-3X genome

    Directory of Open Access Journals (Sweden)

    Carrère Sébastien

    2008-04-01

    Full Text Available Abstract Background Spiroplama citri, the causal agent of citrus stubborn disease, is a bacterium of the class Mollicutes and is transmitted by phloem-feeding leafhopper vectors. In order to characterize candidate genes potentially involved in spiroplasma transmission and pathogenicity, the genome of S. citri strain GII3-3X is currently being deciphered. Results Assembling 20,000 sequencing reads generated seven circular contigs, none of which fit the 1.8 Mb chromosome map or carried chromosomal markers. These contigs correspond to seven plasmids: pSci1 to pSci6, with sizes ranging from 12.9 to 35.3 kbp and pSciA of 7.8 kbp. Plasmids pSci were detected as multiple copies in strain GII3-3X. Plasmid copy numbers of pSci1-6, as deduced from sequencing coverage, were estimated at 10 to 14 copies per spiroplasma cell, representing 1.6 Mb of extrachromosomal DNA. Genes encoding proteins of the TrsE-TraE, Mob, TraD-TraG, and Soj-ParA protein families were predicted in most of the pSci sequences, in addition to members of 14 protein families of unknown function. Plasmid pSci6 encodes protein P32, a marker of insect transmissibility. Plasmids pSci1-5 code for eight different S. citri adhesion-related proteins (ScARPs that are homologous to the previously described protein P89 and the S. kunkelii SkARP1. Conserved signal peptides and C-terminal transmembrane alpha helices were predicted in all ScARPs. The predicted surface-exposed N-terminal region possesses the following elements: (i 6 to 8 repeats of 39 to 42 amino acids each (sarpin repeats, (ii a central conserved region of 330 amino acids followed by (iii a more variable domain of about 110 amino acids. The C-terminus, predicted to be cytoplasmic, consists of a 27 amino acid stretch enriched in arginine and lysine (KR and an optional 23 amino acid stretch enriched in lysine, aspartate and glutamate (KDE. Plasmids pSci mainly present a linear increase of cumulative GC skew except in regions presenting

  11. Acción inhibitoria de una cepa de Zymomonas mobilis mobilis aislada de caña de azúcar sobre Xanthomonas citri subsp. citri, agente causal de la cancrosis de los cítricos Inhibition of Xanthomonas citri subsp. citri, causal agent of citrus canker, by a strain of Zymomonas mobilis mobilis isolated from sugarcane

    Directory of Open Access Journals (Sweden)

    María E. Romero

    2008-06-01

    Full Text Available Zymomonas mobilis mobilis (Zm produce factores antimicrobianos que actúan sobre un amplio espectro de microorganismos patógenos para el hombre, animales y plantas. Un problema importante a resolver en los tratamientos con antimicrobianos, es el desarrollo de resistencia a compuestos empleados actualmente, no siendo las bacterias fitopatógenas una excepción. En el presente trabajo se realizaron ensayos de antagonismo con células (pruebas de estrías cruzadas y sobrenadantes concentrados (Sc (por difusión en agar preparados a partir de cultivos de Zm (aislada de jugo de caña de azúcar producido en Tucumán, frente a la bacteria causal de la cancrosis: Xanthomonas citri subsp. citri. Se evaluaron aislamientos de Xcc sensibles (Xc y resistentes (Xcr a compuestos a base de cobre. Los resultados obtenidos mostraron que la bacteria testigo fue inhibida totalmente por las células de Zm, ejerciendo un efecto bactericida. En los ensayos de difusión en el agar se observó que tanto Xc, como Xcr fueron sensibles al Sc de Zm. Se sabe, por estudios anteriores, que los metabolitos de Zymomonas tienen un efecto deletéreo en la membrana celular de E. coli AB1133, inhibiéndose la respiración de la bacteria inmediatamente de agregado Sc (60 UA. En el presente trabajo se observó el mismo efecto, inhibición total de la respiración en Xc, luego del agregado del Sc (60 UA. Por lo observado, se deduce que el blanco de acción de los metabolitos antimicrobianos de Sc en Xc, sería el mismo que el de E. coli AB1133. Con los resultados obtenidos se considera de interés encarar el estudio de los compuestos de Zm para ser empleados en el control de enfermedades que afectan los cultivos de valor económico de la región, como es el caso de la cancrosis, como así también profundizar acerca de la acción de dichos metabolitos en la membrana de Xanthomonas citri subsp. citri.Zymomonas mobilis mobilis (Zm produces antimicrobial factors, which have an effect on

  12. Optimization of PV-based energy production by dynamic PV-panel/inverter configuration

    DEFF Research Database (Denmark)

    Paasch, Kasper; Nymand, Morten; Haase, Frerk

    This paper investigates the possible increase in annual energy production of a PV system with more than one MPPT (maximum power point tracker) input channels under Nordic illumination conditions, in case a concept of dynamic switching of the PV panels is used at the inputs of the inverters....

  13. Involvement of Three Esterase Genes from Panonychus citri (McGregor in Fenpropathrin Resistance

    Directory of Open Access Journals (Sweden)

    Xiao-Min Shen

    2016-08-01

    Full Text Available The citrus red mite, Panonychus citri (McGregor, is a major citrus pest with a worldwide distribution and an extensive record of pesticide resistance. However, the underlying molecular mechanism associated with fenpropathrin resistance in this species have not yet been reported. In this study, synergist triphenyl phosphate (TPP dramatically increased the toxicity of fenpropathrin, suggesting involvement of carboxylesterases (CarEs in the metabolic detoxification of this insecticide. The subsequent spatiotemporal expression pattern analysis of PcE1, PcE7 and PcE9 showed that three CarEs genes were all over-expressed after insecticide exposure and higher transcripts levels were observed in different field resistant strains of P. citri. Heterologous expression combined with 3-(4,5-dimethyl-thiazol-2-yl-2,5-diphenyltetra-zolium bromide (MTT cytotoxicity assay in Spodoptera frugiperda (Sf9 cells revealed that PcE1-, PcE7- or PcE9-expressing cells showed significantly higher cytoprotective capability than parental Sf9 cells against fenpropathrin, demonstrating that PcEs probably detoxify fenpropathrin. Moreover, gene silencing through the method of leaf-mediated dsRNA feeding followed by insecticide bioassay increased the mortalities of fenpropathrin-treated mites by 31% (PcE1, 27% (PcE7 and 22% (PcE9, respectively, after individual PcE gene dsRNA treatment. In conclusion, this study provides evidence that PcE1, PcE7 and PcE9 are functional genes mediated in fenpropathrin resistance in P. citri and enrich molecular understanding of CarEs during the resistance development of the mite.

  14. Involvement of Three Esterase Genes from Panonychus citri (McGregor) in Fenpropathrin Resistance.

    Science.gov (United States)

    Shen, Xiao-Min; Liao, Chong-Yu; Lu, Xue-Ping; Wang, Zhe; Wang, Jin-Jun; Dou, Wei

    2016-08-19

    The citrus red mite, Panonychus citri (McGregor), is a major citrus pest with a worldwide distribution and an extensive record of pesticide resistance. However, the underlying molecular mechanism associated with fenpropathrin resistance in this species have not yet been reported. In this study, synergist triphenyl phosphate (TPP) dramatically increased the toxicity of fenpropathrin, suggesting involvement of carboxylesterases (CarEs) in the metabolic detoxification of this insecticide. The subsequent spatiotemporal expression pattern analysis of PcE1, PcE7 and PcE9 showed that three CarEs genes were all over-expressed after insecticide exposure and higher transcripts levels were observed in different field resistant strains of P. citri. Heterologous expression combined with 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetra-zolium bromide (MTT) cytotoxicity assay in Spodoptera frugiperda (Sf9) cells revealed that PcE1-, PcE7- or PcE9-expressing cells showed significantly higher cytoprotective capability than parental Sf9 cells against fenpropathrin, demonstrating that PcEs probably detoxify fenpropathrin. Moreover, gene silencing through the method of leaf-mediated dsRNA feeding followed by insecticide bioassay increased the mortalities of fenpropathrin-treated mites by 31% (PcE1), 27% (PcE7) and 22% (PcE9), respectively, after individual PcE gene dsRNA treatment. In conclusion, this study provides evidence that PcE1, PcE7 and PcE9 are functional genes mediated in fenpropathrin resistance in P. citri and enrich molecular understanding of CarEs during the resistance development of the mite.

  15. Responsiveness of different citrus genotypes to the Xanthomonas citri ssp. citri-derived pathogen-associated molecular pattern (PAMP) flg22 correlates with resistance to citrus canker.

    Science.gov (United States)

    Shi, Qingchun; Febres, Vicente J; Jones, Jeffrey B; Moore, Gloria A

    2015-06-01

    The bacterial agent of citrus canker disease (Xanthomonas citri ssp. citri, Xcc) has caused tremendous economic losses to the citrus industry around the world. Pathogen-associated molecular pattern (PAMP)-triggered immunity (PTI) is important to plant immunity. In this study, we compared the defence responses of citrus canker-resistant and citrus canker-susceptible genotypes to the Xcc-derived PAMP flg22 (Xflg22) by analysing the expression of 20 citrus defence-associated genes. We showed that, in the most resistant genotype, 'Nagami' kumquat, there was significant induction of several defence genes (EDS1, NDR1, PBS1, RAR1, SGT1, PAL1, NPR2 and NPR3) as early as 6 h and up to 72 h after Xflg22 treatment. At the other end of the spectrum, highly susceptible 'Duncan' grapefruit showed no induction of the same defence genes, even 120 h after treatment. Citrus genotypes with partial levels of resistance showed intermediate levels of transcriptional reprogramming that correlated with their resistance level. Xflg22 also triggered a rapid oxidative burst in all genotypes which was higher and accompanied by the induction of PTI marker genes (WRKY22 and GST1) only in the more resistant genotypes. Pretreatment with Xflg22 prior to Xcc inoculation inhibited bacterial growth in kumquat, but not in grapefruit. A flagellin-deficient Xcc strain (XccΔfliC) showed greater growth increase relative to wild-type Xcc in kumquat than in grapefruit. Taken together, our results indicate that Xflg22 initiates strong PTI in canker-resistant genotypes, but not in susceptible ones, and that a robust induction of PTI is an important component of citrus resistance to canker.

  16. Chemical composition and fungicidal activity of the essential oil of Thymus vulgaris against Alternaria citri

    Directory of Open Access Journals (Sweden)

    Erica A. Soto Mendívil

    2006-01-01

    Full Text Available Se analizó químicamente el aceite esencial de tomillo (Thymus vulgaris L. por Cromatografía de Gases/Espectroscopia de Masas y se evaluó su actividad fungicida. Los principales constituyentes fueron borneol (28.4%, timol (16.6%, carvacrol metil eter (9.6%, camfeno (6.9%, α-humulene (6.4% y carvacrol (5.0%. Las pruebas de actividad fungicida (in vitro indicaron que la concentración de 1000ppm del aceite esencial de tomillo fue efectivo para inhibir a Alternaria citri, cuando se adicionó al medio de cultivo agar papa dextrosa

  17. Pathogenesis of Hepatic Encephalopathy

    Directory of Open Access Journals (Sweden)

    Irena Ciećko-Michalska

    2012-01-01

    Full Text Available Hepatic encephalopathy can be a serious complication of acute liver failure and chronic liver diseases, predominantly liver cirrhosis. Hyperammonemia plays the most important role in the pathogenesis of hepatic encephalopathy. The brain-blood barrier disturbances, changes in neurotransmission, neuroinflammation, oxidative stress, GABA-ergic or benzodiazepine pathway abnormalities, manganese neurotoxicity, brain energetic disturbances, and brain blood flow abnormalities are considered to be involved in the development of hepatic encephalopathy. The influence of small intestine bacterial overgrowth (SIBO on the induction of minimal hepatic encephalopathy is recently emphasized. The aim of this paper is to present the current views on the pathogenesis of hepatic encephalopathy.

  18. PV performance modeling workshop summary report.

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Joshua S.; Tasca, Coryne Adelle (SRA International, Inc., Fairfax, VA); Cameron, Christopher P.

    2011-05-01

    During the development of a solar photovoltaic (PV) energy project, predicting expected energy production from a system is a key part of understanding system value. System energy production is a function of the system design and location, the mounting configuration, the power conversion system, and the module technology, as well as the solar resource. Even if all other variables are held constant, annual energy yield (kWh/kWp) will vary among module technologies because of differences in response to low-light levels and temperature. A number of PV system performance models have been developed and are in use, but little has been published on validation of these models or the accuracy and uncertainty of their output. With support from the U.S. Department of Energy's Solar Energy Technologies Program, Sandia National Laboratories organized a PV Performance Modeling Workshop in Albuquerque, New Mexico, September 22-23, 2010. The workshop was intended to address the current state of PV system models, develop a path forward for establishing best practices on PV system performance modeling, and set the stage for standardization of testing and validation procedures for models and input parameters. This report summarizes discussions and presentations from the workshop, as well as examines opportunities for collaborative efforts to develop objective comparisons between models and across sites and applications.

  19. PV system field experience and reliability

    Science.gov (United States)

    Durand, Steven; Rosenthal, Andrew; Thomas, Mike

    1997-02-01

    Hybrid power systems consisting of battery inverters coupled with diesel, propane, or gasoline engine-driven electrical generators, and photovoltaic arrays are being used in many remote locations. The potential cost advantages of hybrid systems over simple engine-driven generator systems are causing hybrid systems to be considered for numerous applications including single-family residential, communications, and village power. This paper discusses the various design constraints of such systems and presents one technique for reducing hybrid system losses. The Southwest Technology Development Institute under contract to the National Renewable Energy Laboratory and Sandia National Laboratories has been installing data acquisition systems (DAS) on a number of small and large hybrid PV systems. These systems range from small residential systems (1 kW PV - 7 kW generator), to medium sized systems (10 kW PV - 20 kW generator), to larger systems (100 kW PV - 200 kW generator). Even larger systems are being installed with hundreds of kilowatts of PV modules, multiple wind machines, and larger diesel generators.

  20. Molecular Pathogenesis of Spondyloarthritis

    DEFF Research Database (Denmark)

    Carlsen, Thomas Gelsing

    This dissertation includes a presentation of knowledge on the molecular pathogenesis of spondyloarthritis achieved through a PhD programme at Aalborg University from 1.12.2011 - 1.12.2014. Work was carried out in the Laboratory of Medical Mass Spectrometry, headed by: Professor Svend Birkelund...

  1. Inflammatory bowel disease: pathogenesis.

    Science.gov (United States)

    Zhang, Yi-Zhen; Li, Yong-Yu

    2014-01-07

    Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, is characterized by chronic relapsing intestinal inflammation. It has been a worldwide health-care problem with a continually increasing incidence. It is thought that IBD results from an aberrant and continuing immune response to the microbes in the gut, catalyzed by the genetic susceptibility of the individual. Although the etiology of IBD remains largely unknown, it involves a complex interaction between the genetic, environmental or microbial factors and the immune responses. Of the four components of IBD pathogenesis, most rapid progress has been made in the genetic study of gut inflammation. The latest internationally collaborative studies have ascertained 163 susceptibility gene loci for IBD. The genes implicated in childhood-onset and adult-onset IBD overlap, suggesting similar genetic predispositions. However, the fact that genetic factors account for only a portion of overall disease variance indicates that microbial and environmental factors may interact with genetic elements in the pathogenesis of IBD. Meanwhile, the adaptive immune response has been classically considered to play a major role in the pathogenesis of IBD, as new studies in immunology and genetics have clarified that the innate immune response maintains the same importance in inducing gut inflammation. Recent progress in understanding IBD pathogenesis sheds lights on relevant disease mechanisms, including the innate and adaptive immunity, and the interactions between genetic factors and microbial and environmental cues. In this review, we provide an update on the major advances that have occurred in above areas.

  2. Investigation of indirect benefits of PV rooftop in Thailand

    Science.gov (United States)

    Khumkrong, T.; Chuangchote, S.; Chenvidhya, D.; Kirtikara, K.

    2017-05-01

    Other than electricity generation, which is the direct benefit of PV rooftop, cooling load reduction due to PV shading is a benefit impact in the uses of PV rooftop. This report is a study of those indirect benefits of PV rooftop. Relation of shading of PV modules and reduction of cooling load was studied in a real testing cite at the office building of CES Solar Cell Testing Center (CSSC). Several data, i.e. solar radiation, rooftop temperatures before/after PV-panel installation, and electricity consumed by equipment, were monitored and collected. This data could be further estimated for cooling load via transient heat conduction approach.

  3. POWERED LED LIGHTING SUPPLIED FROM PV CELLS

    Directory of Open Access Journals (Sweden)

    Tirshu M.

    2011-12-01

    Full Text Available The paper deals with practical realization of efficient lighting system based on LED’s of 80W total power mounted on corridor ceiling total length of which is 120m and substitutes existing traditional lighting system consisting of 29 lighting blocks with 4 fluorescent lamps each of them and summary power 2088W. Realized lighting system is supplied from two photovoltaic panels of power 170W. Generated energy by PV cells is accumulated in two accumulators of 75Ah capacity and from battery by means of specialized convertor is applied to lighting system. Additionally, paper present data measured by digital weather station (solar radiation and UV index, which is mounted near of PV cells and comparative analyze of solar energy with real energy generated by PV cells is done. Measured parameters by digital weather station are stored by computer in on-line mode.

  4. PV Systems Reliability Final Technical Report.

    Energy Technology Data Exchange (ETDEWEB)

    Lavrova, Olga [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Flicker, Jack David [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Johnson, Jay [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Armijo, Kenneth Miguel [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Gonzalez, Sigifredo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Schindelholz, Eric John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Sorensen, Neil R. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Yang, Benjamin Bing-Yeh [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    The continued exponential growth of photovoltaic technologies paves a path to a solar-powered world, but requires continued progress toward low-cost, high-reliability, high-performance photovoltaic (PV) systems. High reliability is an essential element in achieving low-cost solar electricity by reducing operation and maintenance (O&M) costs and extending system lifetime and availability, but these attributes are difficult to verify at the time of installation. Utilities, financiers, homeowners, and planners are demanding this information in order to evaluate their financial risk as a prerequisite to large investments. Reliability research and development (R&D) is needed to build market confidence by improving product reliability and by improving predictions of system availability, O&M cost, and lifetime. This project is focused on understanding, predicting, and improving the reliability of PV systems. The two areas being pursued include PV arc-fault and ground fault issues, and inverter reliability.

  5. Terawatt Challenge for Thin-Film PV

    Energy Technology Data Exchange (ETDEWEB)

    Zweibel, K.

    2005-08-01

    The evolution of PV into one of the world's largest industries is not going to happen without major unforeseen problems. However, this study attempts to address the obvious ones, so that we can put aside the mythology of PV (for example, that it is only ''boutique power'' or that one must pave the world with it to be useful) and get on with changing the world's energy infrastructure. With the years of rapid market growth now under way in PV, the author is sure this will not be the last effort to understand the real potential and pitfalls of meeting the Challenge.

  6. PV panel model based on datasheet values

    DEFF Research Database (Denmark)

    Sera, Dezso; Teodorescu, Remus; Rodriguez, Pedro

    2007-01-01

    This work presents the construction of a model for a PV panel using the single-diode five-parameters model, based exclusively on data-sheet parameters. The model takes into account the series and parallel (shunt) resistance of the panel. The equivalent circuit and the basic equations of the PV cell....../panel in Standard Test Conditions (STC) are shown, as well as the parameters extraction from the data-sheet values. The temperature dependence of the cell dark saturation current is expressed with an alternative formula, which gives better correlation with the datasheet values of the power temperature dependence....... Based on these equations, a PV panel model, which is able to predict the panel behavior in different temperature and irradiance conditions, is built and tested....

  7. Influence of Host Plant Species and Flush Growth Stage on the Asian Citrus Psyllid, Diaphorina citri Kuwayama

    Directory of Open Access Journals (Sweden)

    Stephen L.C. Teck

    2011-01-01

    Full Text Available Problem statement: In order to establish the important host range of D. citri, the performance of this psyllid on different rutacous host plants was assessed. Apparent regional differences in host preferences of D. citri as noted above and the need for empirical knowledge of its host preferences in Malaysia where it is lacking. Approach: Experiments on host plant preference between citrus, jasmine orange and curry leaf were conducted over a period of 14 days in the field cage in October 1998 at the agricultural research centre, Semonggok, 15 km from Kuching, Kuching Division, Sarawak in Malaysia. Results: A comparative life cycle study of the Asian Citrus Psyllid Diaphorina citri Kuwayama on three different Rutaceous plant hosts namely citrus, jasmine orange and curry leaf plants was conducted inside the temperature controlled growth chamber maintain at 26 ± 1°C temperature, 75-80% relative humidity with artificial illumination intensity of 10,000 lux equipped with a photoperiod of 14:10 h light: dark regime to permit normal growth. Conclusion: The screenhouse studies confirmed that D. citri can colonise and breed on citrus, jasmine orange and curry leaf plant and that jasmine orange is the preferred host. It is also confirmed that females prefer to oviposit on immature flush 3-10 mm in length. In growth chamber experiments the life cycle of the psyllid was 18.5 days on jasmine orange, 19.0 days on citrus and 23.0 days on curry leaf.

  8. Species limits in Diaporthe: molecular re-assessment of D. citri, D. cytosporella, D. foeniculina and D. rudis

    NARCIS (Netherlands)

    Udayanga, D.; Castlebury, L.A.; Rossman, A.Y.; Hyde, K.D.

    2014-01-01

    Species of Diaporthe are important plant pathogens of a wide range of hosts worldwide. In the present study the species causing melanose and stem end rot diseases of Citrus spp. are revised. Three species of Diaporthe occurring on Citrus are characterised, including D. citri, D. cytosporella and D.

  9. Biocuration and improvement of the Diaphorina citri draft genome assembly with long reads, optical maps and long-range scaffolding

    Science.gov (United States)

    The Asian citrus psyllid (Diaphorina citri Kuwayama) is the insect vector of the bacterium Candidatus Liberibacter asiaticus (CLas), the causal agent for the citrus greening or Huanglongbing disease which threatens citrus industry worldwide. This vector is the primary target of approaches to stop th...

  10. Identification and Characterization of Seven Glutathione S-Transferase Genes from Citrus Red Mite, Panonychus citri (McGregor

    Directory of Open Access Journals (Sweden)

    Chong-Yu Liao

    2013-12-01

    Full Text Available The citrus red mite, Panonychus citri (McGregor, is a global citrus pest, and has developed severe resistance to several types of acaricides. However, the molecular mechanisms of resistance in this mite remain unknown. In this study, seven full-length cDNAs encoding glutathione S-transferases (GSTs genes were identified and characterized in P. citri. The effects of pyridaben and fenpropathrin exposure on the expression of these genes were also investigated. Phylogenetic analysis revealed that the seven GSTs genes in P. citri cloned in this study belong to three different cytosolic classes, including four in mu, two in delta and one in zeta. Among these seven GSTs genes, the relative expression level of PcGSTm1 was significantly higher in adult than in the other life stages (egg, larvae and nymph. Compared with the control, the mRNA levels of the seven GST genes did not change significantly following exposure to pyridaben at LC10. However, RT-qPCR results showed that, when exposed to LC10 of fenpropathrin, six GSTs gene (PcGSTm1, PcGSTm3, PcGSTm4, PcGSTd1, PcGSTd2 and PcGSTz1 transcripts increased in a time-dependent manner. This is the first insight into the molecular characteristics of GSTs gene cDNAs in P. citri. The elevated GSTs gene transcripts following exposure to fenpropathrin might be one of the mechanisms involved in detoxification of this acaricide.

  11. Complete genome sequence of Spiroplasma citri strain R8-A2T, causal agent of stubborn disease in Citrus spp.

    Science.gov (United States)

    Spiroplasma citri is the causal agent of stubborn disease in Citrus spp., as well as the cause of diseases in numerous other plant genera. Here we report the nucleotide sequence of the 1,599,709 bp circular chromosome and two plasmids of strain R8-A2T. This information will facilitate comparative ...

  12. Toxicity of insecticidal soaps to the Asian citrus psyllid (Diaphorina citri) and two of its natural enemies

    Science.gov (United States)

    Insecticidal soaps (hereafter “soaps”) are labeled for use by homeowners and also can be used in citrus grown for the organic market. Soaps control some insect pests and therefore might be an alternative to conventional pesticides for control of the Asian citrus psyllid, Diaphorina citri Kuwayama (...

  13. Real time PV manufacturing diagnostic system

    Energy Technology Data Exchange (ETDEWEB)

    Kochergin, Vladimir [MicroXact Inc., Blacksburg, VA (United States); Crawford, Michael A. [MicroXact Inc., Blacksburg, VA (United States)

    2015-09-01

    The main obstacle Photovoltaic (PV) industry is facing at present is the higher cost of PV energy compared to that of fossil energy. While solar cell efficiencies continue to make incremental gains these improvements are so far insufficient to drive PV costs down to match that of fossil energy. Improved in-line diagnostics however, has the potential to significantly increase the productivity and reduce cost by improving the yield of the process. On this Phase I/Phase II SBIR project MicroXact developed and demonstrated at CIGS pilot manufacturing line a high-throughput in-line PV manufacturing diagnostic system, which was verified to provide fast and accurate data on the spatial uniformity of thickness, an composition of the thin films comprising the solar cell as the solar cell is processed reel-to-reel. In Phase II project MicroXact developed a stand-alone system prototype and demonstrated the following technical characteristics: 1) ability of real time defect/composition inconsistency detection over 60cm wide web at web speeds up to 3m/minute; 2) Better than 1mm spatial resolution on 60cm wide web; 3) an average better than 20nm spectral resolution resulting in more than sufficient sensitivity to composition imperfections (copper-rich and copper-poor regions were detected). The system was verified to be high vacuum compatible. Phase II results completely validated both technical and economic feasibility of the proposed concept. MicroXact’s solution is an enabling technique for in-line PV manufacturing diagnostics to increase the productivity of PV manufacturing lines and reduce the cost of solar energy, thus reducing the US dependency on foreign oil while simultaneously reducing emission of greenhouse gasses.

  14. Novel Methods to Determine Feeder Locational PV Hosting Capacity and PV Impact Signatures

    Energy Technology Data Exchange (ETDEWEB)

    Reno, Matthew J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Coogan, Kyle [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Seuss, John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Broderick, Robert Joseph [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    Often PV hosting capacity analysis is performed for a limited number of distribution feeders. For medium - voltage distribution feeders, previous results generally analyze less than 20 feeders, and then the results are extrapolated out to similar types of feeders. Previous hosting capacity research has often focused on determining a single value for the hosting capacity for the entire feeder, whereas this research expands previous hosting capacity work to investigate all the regions of the feeder that may allow many different hosting capacity values wit h an idea called locational hosting capacity (LHC)to determine the largest PV size that can be interconnected at different locations (buses) on the study feeders. This report discusses novel methods for analyzing PV interconnections with advanced simulati on methods. The focus is feeder and location - specific impacts of PV that determine the locational PV hosting capacity. Feeder PV impact signature are used to more precisely determine the local maximum hosting capacity of individual areas of the feeder. T he feeder signature provides improved interconnection screening with certain zones that show the risk of impact to the distribution feeder from PV interconnections.

  15. Characterization of the sulfate uptake and assimilation pathway from Xanthomonas citri - targets for bacterial growth inhibitors

    Energy Technology Data Exchange (ETDEWEB)

    Tambascia, C.; Balan, A. [Laboratorio Nacional de Biociencias - LNBIO, Campinas, SP (Brazil)

    2012-07-01

    Full text: Microorganisms require sulfur for growth and obtain it either for inorganic sulfate or organosulfur compounds. ATP-Binding Cassete (SulT family) or major facilitator superfamily-type (SulP) transporters are responsible for the sulfate transport into the cell. In Xanthomonas citri, the phytopathogenic bacterium that causes the canker citrus disease, there are no reports related to the importance of these transporters during in vitro or in vivo infection. We identified in X. citri genome all the genes that belong to the well-characterized cys regulon from Escherichia coli and Salmonella typhimurium, which includes three ABC transporters and all the enzymes necessary for sulfate oxide reduction to sulfide and cysteine. Once these genes have been shown to be extremely important for bacteria growth and development in different environments, we chose the sbpcysWUA and cysDNCHIJG operons, which encodes the ABC inorganic sulfate ABC transporter and all the enzymes necessary for conversion of sulfate in cysteine, respectively. As a step for crystallization trials and resolution of their tridimensional structures, the referred genes were amplified and cloned into the cloning vector pGEM T-easy. In addition, using bioinformatics tools and molecular modeling we characterized all the protein functions as well as built tridimensional models of their structure for determination of the active sites. The importance of each protein is discussed aiming the discovery of a good target for development of inhibitors that could block the bacterium growth. (author)

  16. Insecticide sprays, natural enemy assemblages and predation on Asian citrus psyllid, Diaphorina citri (Hemiptera: Psyllidae).

    Science.gov (United States)

    Monzo, C; Qureshi, J A; Stansly, P A

    2014-10-01

    The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama is considered a key citrus pest due to its role as vector of 'huanglongbing' (HLB) or citrus greening, probably the most economically damaging disease of citrus. Insecticidal control of the vector is still considered a cornerstone of HLB management to prevent infection and to reduce reinoculation of infected trees. The severity of HLB has driven implementation of intensive insecticide programs against ACP with unknown side effects on beneficial arthropod fauna in citrus agroecosystems. We evaluated effects of calendar sprays directed against this pest on natural enemy assemblages and used exclusion to estimate mortality they imposed on ACP populations in citrus groves. Predator exclusion techniques were used on nascent colonies of D. citri in replicated large untreated and sprayed plots of citrus during the four major flushing periods over 2 years. Population of spiders, arboreal ants and ladybeetles were independently assessed. Monthly sprays of recommended insecticides for control of ACP, adversely affected natural enemy populations resulting in reduced predation on ACP immature stages, especially during the critical late winter/early spring flush. Consequently, projected growth rates of the ACP population were greatest where natural enemies had been adversely affected by insecticides. Whereas, this result does not obviate the need for insecticidal control of ACP, it does indicate that even a selective regimen of sprays can impose as yet undetermined costs in terms of reduced biological control of this and probably other citrus pests.

  17. Development and reproduction of Panonychus citri (Prostigmata: Tetranychidae) on different species and varieties of citrus plants.

    Science.gov (United States)

    Zanardi, Odimar Zanuzo; Bordini, Gabriela Pavan; Franco, Aline Aparecida; de Morais, Matheus Rovere; Yamamoto, Pedro Takao

    2015-12-01

    The species and varieties of citrus plants that are currently grown can favor the population growth of the citrus red mite Panonychus citri (McGregor) (Prostigmata: Tetranychidae) and alter the pest management programs in citrus groves. In this study we evaluated, in the laboratory, the development and reproduction of P. citri and estimated its life table parameters when reared on four varieties of Citrus sinensis (L.) Osbeck (Valencia, Pera, Natal, and Hamlin), one variety of Citrus reticulata Blanco (Ponkan) and one variety of Citrus limon (L.) Burm. (Sicilian). The incubation period and egg viability were not affected by the host plant. However, the development and survival of the immature stage were significantly lower on Hamlin orange than on Valencia, Pera and Natal oranges, Ponkan mandarin and Sicilian lemon. The fecundity and oviposition period of females were lower on Hamlin orange than on the other hosts. Mites reared on Valencia orange and Sicilian lemon had a higher net reproductive rate (R 0 ), intrinsic growth rate (r) and finite rate of increase (λ), and a shorter interval between generations (T) than on Pera, Natal and Hamlin oranges and Ponkan mandarin. On the other hand, mites reared on Hamlin orange had the lowest R 0 , r and λ and the highest T among the hosts. Based on the results obtained we recommend that for Valencia orange and Sicilian lemon, the mite monitoring programs should be more intense to detect the initial infestation of pest, avoiding the damage in plants and the increase in production costs.

  18. Seasonal energy storage - PV-hydrogen systems

    Energy Technology Data Exchange (ETDEWEB)

    Leppaenen, J. [Neste Oy/NAPS (Finland)

    1998-10-01

    PV systems are widely used in remote areas e.g. in telecommunication systems. Typically lead acid batteries are used as energy storage. In northern locations seasonal storage is needed, which however is too expensive and difficult to realise with batteries. Therefore, a PV- battery system with a diesel backup is sometimes used. The disadvantages of this kind of system for very remote applications are the need of maintenance and the need to supply the fuel. To overcome these problems, it has been suggested to use hydrogen technologies to make a closed loop autonomous energy storage system

  19. Updating Interconnection Screens for PV System Integration

    Energy Technology Data Exchange (ETDEWEB)

    Coddington, M.; Mather, B.; Kroposki, B.; Lynn, K.; Razon, A.; Ellis, A.; Hill, R.; Key, T.; Nicole, K.; Smith, J.

    2012-02-01

    This white paper evaluates the origins and usefulness of the capacity penetration screen, offer short-term solutions which could effectively allow fast-track interconnection to many PV system applications, and considers longer-term solutions for increasing PV deployment levels in a safe and reliable manner while reducing or eliminating the emphasis on the penetration screen. Short-term and longer-term alternatives approaches are offered as examples; however, specific modifications to screening procedures should be discussed with stakeholders and must ultimately be adopted by state and federal regulatory bodies.

  20. MPPT algorithm for voltage controlled PV inverters

    DEFF Research Database (Denmark)

    Kerekes, Tamas; Teodorescu, Remus; Liserre, Marco;

    2008-01-01

    This paper presents a novel concept for an MPPT that can be used in case of a voltage controlled grid connected PV inverters. In case of single-phase systems, the 100 Hz ripple in the AC power is also present on the DC side. Depending on the DC link capacitor, this power fluctuation can be used t...... to track the MPP of the PV array, using the information that at MPP the power oscillations are very small. In this way the algorithm can detect the fact that the current working point is at the MPP, for the current atmospheric conditions....

  1. Large-Scale PV Integration Study

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Shuai; Etingov, Pavel V.; Diao, Ruisheng; Ma, Jian; Samaan, Nader A.; Makarov, Yuri V.; Guo, Xinxin; Hafen, Ryan P.; Jin, Chunlian; Kirkham, Harold; Shlatz, Eugene; Frantzis, Lisa; McClive, Timothy; Karlson, Gregory; Acharya, Dhruv; Ellis, Abraham; Stein, Joshua; Hansen, Clifford; Chadliev, Vladimir; Smart, Michael; Salgo, Richard; Sorensen, Rahn; Allen, Barbara; Idelchik, Boris

    2011-07-29

    This research effort evaluates the impact of large-scale photovoltaic (PV) and distributed generation (DG) output on NV Energy’s electric grid system in southern Nevada. It analyzes the ability of NV Energy’s generation to accommodate increasing amounts of utility-scale PV and DG, and the resulting cost of integrating variable renewable resources. The study was jointly funded by the United States Department of Energy and NV Energy, and conducted by a project team comprised of industry experts and research scientists from Navigant Consulting Inc., Sandia National Laboratories, Pacific Northwest National Laboratory and NV Energy.

  2. International PV QA Task Force's Proposed Comparative Rating System for PV Modules: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Wohlgemuth, J.; Kurtz, S.

    2014-10-01

    The International PV Quality Assurance Task Force is developing a rating system that provides comparative information about the relative durability of PV modules. Development of accelerated stress tests that can provide such comparative information is seen as a major step toward being able to predict PV module service life. This paper will provide details of the ongoing effort to determine the format of such an overall module rating system. The latest proposal is based on using three distinct climate zones as defined in IEC 60721-2-1 for two different mounting systems. Specific stresses beyond those used in the qualification tests are being developed for each of the selected climate zones.

  3. Evaluation of six different groups of insecticides for the control of citrus psylla Diaphorina citri (Hemiptera: Psyllidae

    Directory of Open Access Journals (Sweden)

    Rakhmin Gul

    2005-01-01

    Full Text Available Studies on the efficacy of different insecticides against citrus psylla, Diaphorina citri (Hemiptera: Psyllidae were carried out at Agricultural Research Institute, Tarnab, Peshawar, Pakistan. Six insecticides viz. Actara 25 WG, (thiamethoxam Cascade 10 DC (Flufenoxuron, Match 050 EC (lufenuron, Thiodan 35 EC (endosulfan, Karate 2.5 EC (α-cyhalothrin, and Supracide 40 EC (methidathion, were tested for their effectiveness against D. citri. After first spray overall mean population of D. citri was 3.63, 4.75, 5.59, 6.66, 7.47, 8.11 per six inches tender shoot on Actara 25 WG, Cascade 10 DC, Match 050 EC, Thiodan 35 EC, Karate 2.5 EC and Supracide 40 EC treated plants respectively, while on control plants the population was 12.39. Similarly, after the second spray of each of the same insecticides the population of D. citri was 2.65, 4.23, 5.61, 6.41, 7.35 and 8.73 respectively. Where in controls there were 15.18 psyllids. Percent decrease of D. citri population in comparison to control after the first spray was highest in Actara 25 WG (72.20 followed by Cascade 10 DC (62.91, Match 050 EC (54.07, Thiodan 35 EC (47.61, Karate 2.5 EC (38.94 and Supracide 40 EC (35.74. After the second spray percent decrease over control recorded was highest in Actara 25 WG (83.54, followed by Cascade 10 DC (71.08, Match 050 EC (63.94, Thiodan 35 EC (60.79, Karate 2.5 EC (52.52 and Supracide 40 EC (45.62.

  4. Analyses of mitogenome sequences revealed that Asian citrus psyllid (Diaphorina citri) from California was related to those from Florida but different from those in Southern China

    Science.gov (United States)

    Asian citrus psyllid (ACP, Diaphorina citri Kuwayama; Hemiptera: Liviidae) transmits “Candidatus Liberibacter asiaticus” (CLas), an unculturable alpha-proteobacterium associated with citrus Huanglongbing (HLB, yellow shoot disease, also called citrus greening disease). HLB is threatening citrus prod...

  5. Signalering van citruswolluis (Planococcus citri) in de teelt van diverse potplanten : onderzoek binnen project 41203147 "Verbetering biologische bestrijding van wolluis in diverse potplanten”

    NARCIS (Netherlands)

    Boertjes, B.C.; Bruin, de J.

    2003-01-01

    In 2002 en 2003 is door PPO Glastuinbouw het project “Verbetering biologische bestrijding van wolluis in diverse potplanten” (project 41203147) uitgevoerd. Binnen dit project werd onder meer onderzoek gedaan naar methoden om citruswolluis (Planococcus citri) te signaleren.

  6. A Practical Irradiance Model for Bifacial PV Modules: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Marion, Bill; MacAlpine, Sara; Deline, Chris; Asgharzadeh, Amir; Toor, Fatima; Riley, Daniel; Stein, Joshua; Hansen, Clifford

    2017-06-15

    A model, suitable for a row or multiple rows of photovoltaic (PV) modules, is presented for estimating the backside irradiance for bifacial PV modules. The model, which includes the effects of shading by the PV rows, is based on the use of configuration factors (CFs) to determine the fraction of a source of irradiance that is received by the backside of the PV module. Backside irradiances are modeled along the sloped height of the PV module, but assumed not to vary along the length of the PV row. The backside irradiances are corrected for angle-of-incidence losses and may be added to the front side irradiance to determine the total irradiance resource for the PV cell. Model results are compared with the measured backside irradiances for NREL and Sandia PV systems, and with results when using the RADIANCE ray tracing program.

  7. A Practical Irradiance Model for Bifacial PV Modules

    Energy Technology Data Exchange (ETDEWEB)

    Marion, Bill; MacAlpine, Sara; Deline, Chris; Asgharzadeh, Amir; Toor, Fatima; Riley, Daniel; Stein, Joshua; Hansen, Clifford

    2017-06-21

    A model, suitable for a row or multiple rows of photovoltaic (PV) modules, is presented for estimating the backside irradiance for bifacial PV modules. The model, which includes the effects of shading by the PV rows, is based on the use of configuration factors to determine the fraction of a source of irradiance that is received by the backside of the PV module. Backside irradiances are modeled along the sloped height of the PV module, but assumed not to vary along the length of the PV row. The backside irradiances are corrected for angle-of-incidence losses and may be added to the front side irradiance to determine the total irradiance resource for the PV cell. Model results are compared with the measured backside irradiances for NREL and Sandia PV systems, and with results when using ray tracing software.

  8. Design optimization of grid-connected PV inverters

    DEFF Research Database (Denmark)

    Koutroulis, Eftichios; Blaabjerg, Frede

    2011-01-01

    The DC/AC inverters are the key elements in grid-connected PV energy production systems. In this paper, new design optimization techniques focused on transformerless (very high efficiency) PV inverters are proposed. They have been developed based on an analysis of the deficiencies of the current......, state-of-the-art PV inverters design technology, which limits the amount of PV energy supplied into the electric grid. The influences of the electric grid regulations and standards and the PV array operational characteristics on the design of grid-connected PV inverters have also been considered....... The simulation results verify that the proposed optimization techniques enable the maximization of the PV energy injected into the electric grid by the optimized PV installation....

  9. Multilocus Sequence Typing Reveals Relevant Genetic Variation and Different Evolutionary Dynamics among Strains of Xanthomonas arboricola pv. juglandis

    Directory of Open Access Journals (Sweden)

    Marco Scortichini

    2010-11-01

    Full Text Available Forty-five Xanthomonas arboricola pv. juglandis (Xaj strains originating from Juglans regia cultivation in different countries were molecularly typed by means of MultiLocus Sequence Typing (MLST, using acnB, gapA, gyrB and rpoD gene fragments. A total of 2.5 kilobases was used to infer the phylogenetic relationship among the strains and possible recombination events. Haplotype diversity, linkage disequilibrium analysis, selection tests, gene flow estimates and codon adaptation index were also assessed. The dendrograms built by maximum likelihood with concatenated nucleotide and amino acid sequences revealed two major and two minor phylotypes. The same haplotype was found in strains originating from different continents, and different haplotypes were found in strains isolated in the same year from the same location. A recombination breakpoint was detected within the rpoD gene fragment. At the pathovar level, the Xaj populations studied here are clonal and under neutral selection. However, four Xaj strains isolated from walnut fruits with apical necrosis are under diversifying selection, suggesting a possible new adaptation. Gene flow estimates do not support the hypothesis of geographic isolation of the strains, even though the genetic diversity between the strains increases as the geographic distance between them increases. A triplet deletion, causing the absence of valine, was found in the rpoD fragment of all 45 Xaj strains when compared with X. axonopodis pv. citri strain 306. The codon adaptation index was high in all four genes studied, indicating a relevant metabolic activity.

  10. On the Impact of Partial Shading on PV Output Power

    DEFF Research Database (Denmark)

    Sera, Dezso; Baghzouz, Yahia

    2008-01-01

    clarifies the mechanism of partial PV shading on a number of PV cells connected in series and/or parallel with and without bypass diodes. The analysis is presented in simple terms and can be useful to someone who wishes to determine the impact of some shading geometry on a PV system. The analysis...... is illustrated by measurements on a commercial 70 W panel, and a 14.4 kW PV array....

  11. Final Technical Report: PV Fault Detection Tool.

    Energy Technology Data Exchange (ETDEWEB)

    King, Bruce Hardison [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Jones, Christian Birk [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    The PV Fault Detection Tool project plans to demonstrate that the FDT can (a) detect catastrophic and degradation faults and (b) identify the type of fault. This will be accomplished by collecting fault signatures using different instruments and integrating this information to establish a logical controller for detecting, diagnosing and classifying each fault.

  12. PV producers must advertise; Werbung wird wichtiger

    Energy Technology Data Exchange (ETDEWEB)

    Seltmann, T.

    2001-01-12

    Producers of current inverters are profiting from the growing PV market. The bigger suppliers are enhancing their advertising and marketing efforts while smaller suppliers opt for high-efficiency technology. [German] Vom kraeftigen Wachstum des Photovoltaik-Marktes profitieren zwangslaeufig auch die Wechselrichter-Hersteller. Die groesseren Anbieter verstaerken Vertrieb und Marketing, waehrend die kleineren versuchen, mit besonders effizienter Technik zu glaenzen. (orig.)

  13. Characterization of Xanthomonas axonopodis pv. phaseoli isolates

    NARCIS (Netherlands)

    Nunes, W.M.C.; Corazza, M.J.; De Souza, S.A.C.D.; Tsai, S.M.; Kuramae, E.E.

    2008-01-01

    A simple, quick and easy protocol was standardized for extraction of total DNA of the bacteria Xanthomonas axonopodis pv. phaseoli. The DNA obtained by this method had high quality and the quantity was enough for the Random Amplified Polymorphic DNA (RAPD) reactions with random primers, and

  14. Characterization of Xanthomonas axonopodis pv. phaseoli isolates

    NARCIS (Netherlands)

    Nunes, W.M.C.; Corazza, M.J.; De Souza, S.A.C.D.; Tsai, S.M.; Kuramae, E.E.

    2008-01-01

    A simple, quick and easy protocol was standardized for extraction of total DNA of the bacteria Xanthomonas axonopodis pv. phaseoli. The DNA obtained by this method had high quality and the quantity was enough for the Random Amplified Polymorphic DNA (RAPD) reactions with random primers, and Polymera

  15. PV-mooduli toodang suurfarmis / Teolan Tomson

    Index Scriptorium Estoniae

    Tomson, Teolan, 1932-

    2015-01-01

    Artiklis uuritakse PV-paneelide tootlikkuse langust nende vastastikuse varjutamise tõttu. Näidatakse, et Eesti oludes on soovitav kasutada paneelide madalaid kaldenurki ja suhtelist reavahet, mis ületab paneeli kõrguse pooleteistkordset väärtust

  16. TRNSYS HYBRID wind diesel PV simulator

    Energy Technology Data Exchange (ETDEWEB)

    Quinlan, P.J.A.; Mitchell, J.W.; Klein, S.A.; Beckman, W.A.; Blair, N.J. [Univ. of Wisconsin, Madison, WI (United States)

    1996-12-31

    The Solar Energy Laboratory (SEL) has developed a wind diesel PV hybrid systems simulator, UW-HYBRID 1.0, an application of the TRNSYS 14.2 time-series simulation environment. An AC/DC bus links up to five diesels and wind turbine models, along with PV modules, a battery bank, and an AC/DC converter. Multiple units can be selected. PV system simulations include solar angle and peak power tracking options. Weather data are Typical Meteorological Year data, parametrically generated synthesized data, or external data files. PV performance simulations rely on long-standing SEL-developed algorithms. Loads data are read as scalable time series. Diesel simulations include estimated fuel-use and waste heat output, and are dispatched using a least-cost of fuel strategy. Wind system simulations include varying air density, wind shear and wake effects. Time step duration is user-selectable. UW-HYBRID 1.0 runs in Windows{reg_sign}, with TRNSED providing a customizable user interface. 12 refs., 6 figs.

  17. PV-mooduli toodang suurfarmis / Teolan Tomson

    Index Scriptorium Estoniae

    Tomson, Teolan, 1932-

    2015-01-01

    Artiklis uuritakse PV-paneelide tootlikkuse langust nende vastastikuse varjutamise tõttu. Näidatakse, et Eesti oludes on soovitav kasutada paneelide madalaid kaldenurki ja suhtelist reavahet, mis ületab paneeli kõrguse pooleteistkordset väärtust

  18. PV/T slates - Pilot project in Steinhausen; PV/T-Schiefer. Pilotprojekt Steinhausen

    Energy Technology Data Exchange (ETDEWEB)

    Kropf, S.

    2003-07-01

    This comprehensive, illustrated report for the Swiss Federal Office of Energy (SFOE) is one a series of five reports dealing with increasing the overall efficiency of photovoltaic (PV) installations by also using the heat collected by the dark-coloured PV panels. The work reported on addresses open questions on the use of the heat and its optimal use. This report deals with a ventilated PV-tile system (PV/T-Slates) mounted on a garden shed in Steinhausen, Switzerland. The installation provides power and heat to the main house. The report describes the construction and operation of this pilot project and the results of measurements made on its electrical and thermal performance. The results of measurements made are presented in detail in graphical form and compared with the results of simulation. Suggestions are made for the optimisation of the system. Figures are presented on energy production and energy flows in graphical form.

  19. Commercialization of PV-powered pumping systems for use in utility PV service programs. Final report

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    The project described in this report was a commercialization effort focused on cost-effective remote water pumping systems for use in utility-based photovoltaic (PV) service programs. The project combined a commercialization strategy tailored specifically for electric utilities with the development of a PV-powered pumping system that operates conventional ac pumps rather than relying on the more expensive and less reliable PV pumps on the market. By combining these two attributes, a project goal was established of creating sustained utility purchases of 250 PV-powered water pumping systems per year. The results of each of these tasks are presented in two parts contained in this Final Summary Report. The first part summarizes the results of the Photovoltaic Services Network (PSN) as a new business venture, while the second part summarizes the results of the Golden Photon system installations. Specifically, results and photographs from each of the system installations are presented in this latter part.

  20. KatG, the Bifunctional Catalase of Xanthomonas citri subsp. citri, Responds to Hydrogen Peroxide and Contributes to Epiphytic Survival on Citrus Leaves.

    Directory of Open Access Journals (Sweden)

    María Laura Tondo

    Full Text Available Xanthomonas citri subsp. citri (Xcc is the bacterium responsible for citrus canker. This bacterium is exposed to reactive oxygen species (ROS at different points during its life cycle, including those normally produced by aerobic respiration or upon exposition to ultraviolet (UV radiation. Moreover, ROS are key components of the host immune response. Among enzymatic ROS-detoxifying mechanisms, catalases eliminate H2O2, avoiding the potential damage caused by this specie. Xcc genome includes four catalase genes. In this work, we studied the physiological role of KatG, the only bifunctional catalase of Xcc, through the construction and characterization of a modified strain (XcckatG, carrying an insertional mutation in the katG gene. First, we evaluated the involvement of KatG in the bacterial adaptive response to H2O2. XcckatG cultures exhibited lower catalase activity than those of the wild-type strain, and this activity was not induced upon treatment with sub-lethal doses of H2O2. Moreover, the KatG-deficient mutant exhibited decreased tolerance to H2O2 toxicity compared to wild-type cells and accumulated high intracellular levels of peroxides upon exposure to sub-lethal concentrations of H2O2. To further study the role of KatG in Xcc physiology, we evaluated bacterial survival upon exposure to UV-A or UV-B radiation. In both conditions, XcckatG showed a high mortality in comparison to Xcc wild-type. Finally, we studied the development of bacterial biofilms. While structured biofilms were observed for the Xcc wild-type, the development of these structures was impaired for XcckatG. Based on these results, we demonstrated that KatG is responsible for Xcc adaptive response to H2O2 and a key component of the bacterial response to oxidative stress. Moreover, this enzyme plays an important role during Xcc epiphytic survival, being essential for biofilm formation and UV resistance.

  1. KatG, the Bifunctional Catalase of Xanthomonas citri subsp. citri, Responds to Hydrogen Peroxide and Contributes to Epiphytic Survival on Citrus Leaves.

    Science.gov (United States)

    Tondo, María Laura; Delprato, María Laura; Kraiselburd, Ivana; Fernández Zenoff, María Verónica; Farías, María Eugenia; Orellano, Elena G

    2016-01-01

    Xanthomonas citri subsp. citri (Xcc) is the bacterium responsible for citrus canker. This bacterium is exposed to reactive oxygen species (ROS) at different points during its life cycle, including those normally produced by aerobic respiration or upon exposition to ultraviolet (UV) radiation. Moreover, ROS are key components of the host immune response. Among enzymatic ROS-detoxifying mechanisms, catalases eliminate H2O2, avoiding the potential damage caused by this specie. Xcc genome includes four catalase genes. In this work, we studied the physiological role of KatG, the only bifunctional catalase of Xcc, through the construction and characterization of a modified strain (XcckatG), carrying an insertional mutation in the katG gene. First, we evaluated the involvement of KatG in the bacterial adaptive response to H2O2. XcckatG cultures exhibited lower catalase activity than those of the wild-type strain, and this activity was not induced upon treatment with sub-lethal doses of H2O2. Moreover, the KatG-deficient mutant exhibited decreased tolerance to H2O2 toxicity compared to wild-type cells and accumulated high intracellular levels of peroxides upon exposure to sub-lethal concentrations of H2O2. To further study the role of KatG in Xcc physiology, we evaluated bacterial survival upon exposure to UV-A or UV-B radiation. In both conditions, XcckatG showed a high mortality in comparison to Xcc wild-type. Finally, we studied the development of bacterial biofilms. While structured biofilms were observed for the Xcc wild-type, the development of these structures was impaired for XcckatG. Based on these results, we demonstrated that KatG is responsible for Xcc adaptive response to H2O2 and a key component of the bacterial response to oxidative stress. Moreover, this enzyme plays an important role during Xcc epiphytic survival, being essential for biofilm formation and UV resistance.

  2. KatG, the Bifunctional Catalase of Xanthomonas citri subsp. citri, Responds to Hydrogen Peroxide and Contributes to Epiphytic Survival on Citrus Leaves

    Science.gov (United States)

    Tondo, María Laura; Delprato, María Laura; Kraiselburd, Ivana; Fernández Zenoff, María Verónica; Farías, María Eugenia; Orellano, Elena G.

    2016-01-01

    Xanthomonas citri subsp. citri (Xcc) is the bacterium responsible for citrus canker. This bacterium is exposed to reactive oxygen species (ROS) at different points during its life cycle, including those normally produced by aerobic respiration or upon exposition to ultraviolet (UV) radiation. Moreover, ROS are key components of the host immune response. Among enzymatic ROS-detoxifying mechanisms, catalases eliminate H2O2, avoiding the potential damage caused by this specie. Xcc genome includes four catalase genes. In this work, we studied the physiological role of KatG, the only bifunctional catalase of Xcc, through the construction and characterization of a modified strain (XcckatG), carrying an insertional mutation in the katG gene. First, we evaluated the involvement of KatG in the bacterial adaptive response to H2O2. XcckatG cultures exhibited lower catalase activity than those of the wild-type strain, and this activity was not induced upon treatment with sub-lethal doses of H2O2. Moreover, the KatG-deficient mutant exhibited decreased tolerance to H2O2 toxicity compared to wild-type cells and accumulated high intracellular levels of peroxides upon exposure to sub-lethal concentrations of H2O2. To further study the role of KatG in Xcc physiology, we evaluated bacterial survival upon exposure to UV-A or UV-B radiation. In both conditions, XcckatG showed a high mortality in comparison to Xcc wild-type. Finally, we studied the development of bacterial biofilms. While structured biofilms were observed for the Xcc wild-type, the development of these structures was impaired for XcckatG. Based on these results, we demonstrated that KatG is responsible for Xcc adaptive response to H2O2 and a key component of the bacterial response to oxidative stress. Moreover, this enzyme plays an important role during Xcc epiphytic survival, being essential for biofilm formation and UV resistance. PMID:26990197

  3. Spatial distribution of Diaphorina citri Kuwayama (Hemiptera: Psyllidae in citrus orchards Distribuição espacial de Diaphorina citri Kuwayama (Hemiptera: Psyllidae em pomares de citros

    Directory of Open Access Journals (Sweden)

    Marilia Gregolin Costa

    2010-10-01

    Full Text Available The psyllid Diaphorina citri Kuwayama is one of the most important pests of citrus, mainly because it is the vector of the bacterium that causes huanglongbing (HLB or 'Greening' disease. To study the spatial distribution of nymphs and adults of this pest, an experiment was carried out in two 'Valencia' sweet orange orchards, four and 12 years of age, established in Matão, central area of São Paulo state, Brazil. The following dispersion indices were used to study pest aggregation in the citrus plants: variance/mean relationship (I, index of Morisita (Iδ, coefficient of Green (Cx, the exponent of negative binomial distribution, common k (c and Taylor's Power Law for each sampling. The negative binomial distribution was more representative of the spatial distribution of this psyllid, for both nymphs and adults. For most samplings, psyllid nymphs found in branches and adults caught in traps had an aggregated distribution.O psilídeo Diaphorina citri Kuwayama tornou-se nos últimos anos uma das mais importantes pragas na cultura de citros, principalmente pelos prejuízos causados às plantas por ser o transmissor da bactéria causadora da doença Huanglongbing (HLB ou 'Greening'. Com a finalidade de estudar a distribuição espacial de ninfas e adultos desta praga, instalaram-se experimentos em duas áreas de citros com histórico de ocorrência de HLB, no município de Matão (região central do Estado de São Paulo, em plantas de laranja 'Valência', com quatro e 12 anos de idade. Para estudo da agregação da população nas plantas, foram utilizados os seguintes índices de dispersão: razão variância/média (I, índice de Morisita (Iδ, coeficiente de Green (Cx e expoente da distribuição binomial negativa, k comum (c e lei da potência de Taylor para cada amostragem. A distribuição binomial negativa foi o modelo mais adequado para representar a distribuição espacial do psilídeo, tanto para ninfas como para adultos. Na maioria das

  4. Impedance characterization of PV modules in outdoor conditions

    DEFF Research Database (Denmark)

    Oprea, Matei-lon; Thorsteinsson, Sune; Spataru, Sergiu

    2016-01-01

    Impedance spectroscopy (IS) has been used for laboratory characterizations of photovoltaic (PV) technologies under well controlled conditions. This work applies IS for outdoor characterization of PV panels, in order to observe the effect of irradiance (G) and temperature (T) on the PV module...

  5. The possibility of developing hybrid PV/T solar system

    Science.gov (United States)

    Dobrnjac, M.; Zivkovic, P.; Babic, V.

    2017-05-01

    An alternative and cost-effective solution to developing integrated PV system is to use hybrid photovoltaic/thermal (PV/T) solar system. The temperature of PV modules increases due to the absorbed solar radiation that is not converted into electricity, causing a decrease in their efficiency. In hybrid PV/T solar systems the reduction of PV module temperature can be combined with a useful fluid heating. In this paper we present the possibility of developing a new hybrid PV/T solar system. Hybrid PV/T system can provide electrical and thermal energy, thus achieving a higher energy conversion rate of the absorbed solar radiation. We developed PV/T prototype consisted of commercial PV module and thermal panel with our original solution of aluminium absorber with special geometric shapes. The main advantages of our combined PV/T system are: removing of heat from the PV panel; extending the lifetime of photovoltaic cells; excess of the removing heat from PV part is used to heat the fluid in the thermal part of the panel; the possibility of using on the roof and facade constructions because less weight.

  6. High Resolution PV Power Modeling for Distribution Circuit Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Norris, B. L.; Dise, J. H.

    2013-09-01

    NREL has contracted with Clean Power Research to provide 1-minute simulation datasets of PV systems located at three high penetration distribution feeders in the service territory of Southern California Edison (SCE): Porterville, Palmdale, and Fontana, California. The resulting PV simulations will be used to separately model the electrical circuits to determine the impacts of PV on circuit operations.

  7. Determination of Parameters of PV Concentrating System With Heliostat

    Science.gov (United States)

    Vardanyan, R.; Norsoyan, A.; Dallakyan, V.

    2010-10-01

    The structure of PV concentrating system with heliostat is analyzed. The mathematical model of system consisting of PV concentrating module and heliostat is developed. With the use of developed mathematical model the optimal parameters of the system are determined. The results of this work can be used during the design of PV concentrating systems with heliostats.

  8. Assessing the need for better forecasting and observability of pv

    DEFF Research Database (Denmark)

    Alet, Pierre-Jean; Efthymiou, Venizelos; Graditi, Giorgio

    2017-01-01

    In its review of the challenges and opportunities associated with massive deployment of solar PV generation, the Grid integration working group of the ETIP PV identified forecasting and observability as critical technologies for the planning and operation of the power system with large PV penetra...

  9. Beacons In Brief. P/PV In Brief. Issue 2

    Science.gov (United States)

    Blank, Susan; Farley, Chelsea

    2004-01-01

    This second issue in P/PV's "In Brief" series focuses on the San Francisco Beacon Initiative and P/PV's recently released evaluation results. The Beacon Initiative established after-school programs in eight public schools in low-income San Francisco neighborhoods. P/PV's 36-month evaluation examined key developmental and academic outcomes.…

  10. Metabolomic Response to Huanglongbing: Role of Carboxylic Compounds in Citrus sinensis Response to 'Candidatus Liberibacter asiaticus' and Its Vector, Diaphorina citri.

    Science.gov (United States)

    Killiny, Nabil; Nehela, Yasser

    2017-08-01

    Huanglongbing, a destructive disease of citrus, is caused by the fastidious bacterium 'Candidatus Liberibacter asiaticus' and transmitted by Asian citrus psyllid, Diaphorina citri. The impact of 'Ca. L. asiaticus' infection or D. citri infestation on Valencia sweet orange (Citrus sinensis) leaf metabolites was investigated using gas chromatography mass spectrometry, followed by gene expression analysis for 37 genes involved in jasmonic acid (JA), salicylic acid (SA), and proline-glutamine pathways. The total amino acid abundance increased after 'Ca. L. asiaticus' infection, while the total fatty acids increased dramatically after infestation with D. citri, compared with control plants. Seven amino acids (glycine, l-isoleucine, l-phenylalanine, l-proline, l-serine, l-threonine, and l-tryptophan) and five organic acids (benzoic acid, citric acid, fumaric acid, SA, and succinic acid) increased in 'Ca. L. asiaticus'-infected plants. On the other hand, the abundance of trans-JA and its precursor α-linolenic increased in D. citri-infested plants. Surprisingly, the double attack of both D. citri infestation and 'Ca. L. asiaticus' infection moderated the metabolic changes in all chemical classes studied. In addition, the gene expression analysis supported these results. Based on these findings, we suggest that, although amino acids such as phenylalanine are involved in citrus defense against 'Ca. L. asiaticus' infection through the activation of an SA-mediated pathway, fatty acids, especially α-linolenic acid, are involved in defense against D. citri infestation via the induction of a JA-mediated pathway.

  11. Citrus tristeza virus-based RNAi in citrus plants induces gene silencing in Diaphorina citri, a phloem-sap sucking insect vector of citrus greening disease (Huanglongbing).

    Science.gov (United States)

    Hajeri, Subhas; Killiny, Nabil; El-Mohtar, Choaa; Dawson, William O; Gowda, Siddarame

    2014-04-20

    A transient expression vector based on Citrus tristeza virus (CTV) is unusually stable. Because of its stability it is being considered for use in the field to control Huanglongbing (HLB), which is caused by Candidatus Liberibacter asiaticus (CLas) and vectored by Asian citrus psyllid, Diaphorina citri. In the absence of effective control strategies for CLas, emphasis has been on control of D. citri. Coincident cohabitation in phloem tissue by CLas, D. citri and CTV was exploited to develop a novel method to mitigate HLB through RNA interference (RNAi). Since CTV has three RNA silencing suppressors, it was not known if CTV-based vector could induce RNAi in citrus. Yet, expression of sequences targeting citrus phytoene desaturase gene by CTV-RNAi resulted in photo-bleaching phenotype. CTV-RNAi vector, engineered with truncated abnormal wing disc (Awd) gene of D. citri, induced altered Awd expression when silencing triggers ingested by feeding D. citri nymphs. Decreased Awd in nymphs resulted in malformed-wing phenotype in adults and increased adult mortality. This impaired ability of D. citri to fly would potentially limit the successful vectoring of CLas bacteria between citrus trees in the grove. CTV-RNAi vector would be relevant for fast-track screening of candidate sequences for RNAi-mediated pest control. Copyright © 2014. Published by Elsevier B.V.

  12. Pathogenesis of Tourette's syndrome.

    Science.gov (United States)

    Leckman, J F; Peterson, B S; Anderson, G M; Arnsten, A F; Pauls, D L; Cohen, D J

    1997-01-01

    This review presents a models of disease pathogenesis in the context of CNS development. It begins with an exploration of the clinical features and natural history of Tourette's syndrome. This is followed by a consideration of the role of genetic and nongenetic factors. An effort is then made to review the anatomical organization of the basal ganglia and related cortical sites. These circuits are intimately involved in the normal processing of sensorimotor, cognitive, and emotionally laden information. Evidence implicating these circuits in the pathobiology of Tourette's syndrome is then considered. The review closes with the prospects for advances in interdisciplinary research and therapeutics using this model as a guide.

  13. Technologies to Increase PV Hosting Capacity in Distribution Feeders: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Fei; Mather, Barry; Gotseff, Peter

    2016-08-01

    This paper studies the distributed photovoltaic (PV) hosting capacity in distribution feeders by using the stochastic analysis approach. Multiple scenario simulations are conducted to analyze several factors that affect PV hosting capacity, including the existence of voltage regulator, PV location, the power factor of PV inverter and Volt/VAR control. Based on the conclusions obtained from simulation results, three approaches are then proposed to increase distributed PV hosting capacity, which can be formulated as the optimization problem to obtain the optimal solution. All technologies investigated in this paper utilize only existing assets in the feeder and therefore are implementable for a low cost. Additionally, the tool developed for these studies is described.

  14. Remote and Centralized Monitoring of PV Power Plants

    DEFF Research Database (Denmark)

    Kopacz, Csaba; Spataru, Sergiu; Sera, Dezso

    2014-01-01

    the inverters within each PV plant. The monitoring software stores the PV measurements in a data warehouse optimized for managing and data mining large amounts of data, from where it can be later visualized, analyzed and exported. By combining PV production measurements data with I-V curve measurements......This paper presents the concept and operating principles of a low-cost and flexible monitoring system for PV plants. Compared to classical solutions which can require dedicated hardware and/or specialized data logging systems, the monitoring system we propose allows parallel monitoring of PV plants...

  15. PV_LIB Toolbox v. 1.3

    Energy Technology Data Exchange (ETDEWEB)

    2015-12-09

    PV_LIB comprises a library of Matlab? code for modeling photovoltaic (PV) systems. Included are functions to compute solar position and to estimate irradiance in the PV system’s plane of array, cell temperature, PV module electrical output, and conversion from DC to AC power. Also included are functions that aid in determining parameters for module performance models from module characterization testing. PV_LIB is open source code primarily intended for research and academic purposes. All algorithms are documented in openly available literature with the appropriate references included in comments within the code.

  16. On Distributed PV Hosting Capacity Estimation, Sensitivity Study, and Improvement

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Fei; Mather, Barry

    2017-07-01

    This paper first studies the estimated distributed PV hosting capacities of seventeen utility distribution feeders using the Monte Carlo simulation based stochastic analysis, and then analyzes the sensitivity of PV hosting capacity to both feeder and photovoltaic system characteristics. Furthermore, an active distribution network management approach is proposed to maximize PV hosting capacity by optimally switching capacitors, adjusting voltage regulator taps, managing controllable branch switches and controlling smart PV inverters. The approach is formulated as a mixed-integer nonlinear optimization problem and a genetic algorithm is developed to obtain the solution. Multiple simulation cases are studied and the effectiveness of the proposed approach on increasing PV hosting capacity is demonstrated.

  17. Technologies to Increase PV Hosting Capacity in Distribution Feeders

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Fei; Mather, Barry; Gotseff, Peter

    2016-11-14

    This paper studies the distributed photovoltaic (PV) hosting capacity in distribution feeders by using the stochastic analysis approach. Multiple scenario simulations are conducted to analyze several factors that affect PV hosting capacity, including the existence of voltage regulator, PV location, the power factor of PV inverter and Volt/VAR control. Based on the conclusions obtained from simulation results, three approaches are then proposed to increase distributed PV hosting capacity, which can be formulated as the optimization problem to obtain the optimal solution. All technologies investigated in this paper utilize only existing assets in the feeder and therefore are implementable for a low cost. Additionally, the tool developed for these studies is described.

  18. Voltage rise mitigation for solar PV integration at LV grids

    DEFF Research Database (Denmark)

    Yang, Guangya; Marra, Francesco; Juamperez Goñi, Miguel Angel

    2015-01-01

    Solar energy from photovoltaic (PV) is among the fastest developing renewable energy systems worldwide. Driven by governmental subsidies and technological development, Europe has seen a fast expansion of solar PV in the last few years. Among the installed PV plants, most of them are situated...... at the distribution systems and bring various operational challenges such as power quality and power flow management. The paper discusses the modelling requirements for PV system integration studies, as well as the possible techniques for voltage rise mitigation at low voltage (LV) grids for increasing PV penetration...

  19. Overexpression of citrus polygalacturonase-inhibiting protein in citrus black rot pathogen Alternaria citri.

    Science.gov (United States)

    Katoh, Hiroshi; Nalumpang, Sarunya; Yamamoto, Hiroyuki; Akimitsu, Kazuya

    2007-05-01

    The rough lemon (Citrus jambhiri) gene encoding polygalacturonase-inhibiting protein (RlemPGIPA) was overexpressed in the pathogenic fungus Alternaria citri. The overexpression mutant AcOPI6 retained the ability to utilize pectin as a sole carbon source, and the overexpression of polygalacturonase-inhibiting protein did not have any effect on the growth of AcOPI6 in potato dextrose and pectin medium. The pathogenicity of AcOPI6 to cause a black rot symptom in citrus fruits was also unchanged. Polygalacturonase-inhibiting protein was secreted together with endopolygalacturonase into culture filtrates of AcOPI6, and oligogalacturonides were digested from polygalacturonic acid by both proteins in the culture filtrates. The reaction mixture containing oligogalacturonides possessed activity for induction of defense-related gene, RlemLOX, in rough lemon leaves.

  20. The Comprehensive Study of Electrical Faults in PV Arrays

    Directory of Open Access Journals (Sweden)

    M. Sabbaghpur Arani

    2016-01-01

    Full Text Available The rapid growth of the solar industry over the past several years has expanded the significance of photovoltaic (PV systems. Fault analysis in solar photovoltaic (PV arrays is a fundamental task to increase reliability, efficiency, and safety in PV systems and, if not detected, may not only reduce power generation and accelerated system aging but also threaten the availability of the whole system. Due to the current-limiting nature and nonlinear output characteristics of PV arrays, faults in PV arrays may not be detected. In this paper, all possible faults that happen in the PV system have been classified and six common faults (shading condition, open-circuit fault, degradation fault, line-to-line fault, bypass diode fault, and bridging fault have been implemented in 7.5 KW PV farm. Based on the simulation results, both normal operational curves and fault curves have been compared.

  1. Optimal Design of Modern Transformerless PV Inverter Topologies

    DEFF Research Database (Denmark)

    Saridakis, Stefanos; Koutroulis, Eftichios; Blaabjerg, Frede

    2013-01-01

    The design optimization of H5, H6, neutral point clamped, active-neutral point clamped, and conergy-NPC transformerless photovoltaic (PV) inverters is presented in this paper. The components reliability in terms of the corresponding malfunctions, affecting the PV inverter maintenance cost during...... the operational lifetime period of the PV installation, is also considered in the optimization process. According to the results of the proposed design method, different optimal values of the PV inverter design variables are derived for each PV inverter topology and installation site. The H5, H6, neutral point...... clamped, active-neutral point clamped and conergy-NPC PV inverters designed using the proposed optimization process feature lower levelized cost of generated electricity and lifetime cost, longer mean time between failures and inject more PV-generated energy into the electric grid than their nonoptimized...

  2. Control químico de Diaphorina citri Kuwayama (Hemíptera: Psyllidae en lima persa Citrus latifolia Tanaka Chemical control of Diaphorina citri Kuwayama (Hemiptera: Psyllidae in Persian lime Citrus latifolia Tanaka

    Directory of Open Access Journals (Sweden)

    Luis Martín Hernández-Fuentes

    2012-06-01

    Full Text Available A nivel mundial, la citricultura representa una actividad de gran importancia. México ocupa el cuarto lugar mundial en producción. Debido a la introducción y dispersión del vector D. citri en todas las zonas citrí colas de México y la reciente detección de la enfermedad conocida como huanglongbing causada por la bacteria Candidatus Liberibacter asiaticus, es necesaria la evaluación de métodos de control de este insecto. En el año 2010 en Nayarit, México, se realizaron pruebas de efectividad técnica en campo y persistencia de productos químicos de diferente mecanismo de acción contra D. citri en lima persa. Se hicieron dos evaluaciones en fechas distintas. En cada ensayo se evaluó número de ninfas por brote y porcentaje de brotes infestados. De los productos evaluados el dimetoato, imidacloprid y la mezcla de imidacloprid más betaciflutrina ejercieron más de 85 % de control de ninfas durante 27 días después de la aplicación. En los árboles tratados con dimetoato e imidacloprid en dosis de 400 mL y 300 mL ha-¹, respectivamente, se observó 100% de brotes libres de ninfas de D. citri a los 27 días después de la aplicación. El aceite agrícola en dosis de dos y tres L ha-1 ejerció menor control de ninfas de D. citri.Citrus crops represent an outstanding activity at worldwide level. Mexico ranks fourth place in production. Due introduction and dispersion of D. citri vector in all citric zones from Mexico and the newly detected disease known as huanglongbing (HLB caused by Candidatus Liberibacter asiaticus bacteria, assessment of control methods for this bug is required. In 2010, technical effectiveness in field and persistence for different action route against Persian lime D. citri chemical products tests were performed in Nayarit, Mexico. Two assessments were made at different dates. The amount of nymphs per shoot and percentage of infested shoots were assessed in each rehearsal. From evaluated products, dimethoate

  3. Pathogenesis of Raynaud's phenomenon.

    Science.gov (United States)

    Herrick, A L

    2005-05-01

    The pathogenesis of Raynaud's phenomenon is not fully understood. However, the last 20 yr have witnessed enormous increases in our understanding of different mechanisms which, singly or in combination, may contribute. A key point is that Raynaud's phenomenon can be either primary (idiopathic) or secondary to a number of underlying conditions, and that the pathogenesis and pathophysiology vary between these conditions. This review concentrates upon those subtypes of Raynaud's phenomenon of most interest to rheumatologists: systemic sclerosis-related Raynaud's phenomenon, primary Raynaud's phenomenon and Raynaud's phenomenon secondary to hand-arm vibration syndrome. In this review, I shall discuss the main mechanisms thought to be important in pathophysiology under the three broad headings of 'vascular', 'neural' and 'intravascular'. While these are false distinctions because all interrelate, they facilitate discussion of the key elements: the blood vessel wall (particularly the endothelium), the neural control of vascular tone, and the many circulating factors which can impair blood flow and/or cause endothelial injury. Vascular abnormalities include those of both structure and function. Neural abnormalities include deficiency of the vasodilator calcitonin gene-related peptide (released from sensory afferents), alpha(2)-adrenoreceptor activation (possibly with up-regulation of the normally 'silent' alpha(2C)-adrenoreceptor) and a central nervous system component. Intravascular abnormalities include platelet activation, impaired fibrinolysis, increased viscosity and probably oxidant stress. As our understanding of the pathophysiology of Raynaud's phenomenon increases, so do our possibilities for identifying effective treatments.

  4. Chemotactic signal transduction and phosphate metabolism as adaptive strategies during citrus canker induction by Xanthomonas citri.

    Science.gov (United States)

    Moreira, Leandro Marcio; Facincani, Agda Paula; Ferreira, Cristiano Barbalho; Ferreira, Rafael Marine; Ferro, Maria Inês Tiraboshi; Gozzo, Fabio Cesar; de Oliveira, Julio Cezar Franco; Ferro, Jesus Aparecido; Soares, Márcia Regina

    2015-03-01

    The genome of Xanthomonas citri subsp. Citri strain 306 pathotype A (Xac) was completely sequenced more than 10 years; to date, few studies involving functional genomics Xac and its host compatible have been developed, specially related to adaptive events that allow the survival of Xac within the plant. Proteomic analysis of Xac showed that the processes of chemotactic signal transduction and phosphate metabolism are key adaptive strategies during the interaction of a pathogenic bacterium with its plant host. The results also indicate the importance of a group of proteins that may not be directly related to the classical virulence factors, but that are likely fundamental to the success of the initial stages of the infection, such as methyl-accepting chemotaxis protein (Mcp) and phosphate specific transport (Pst). Furthermore, the analysis of the mutant of the gene pstB which codifies to an ABC phosphate transporter subunit revealed a complete absence of citrus canker symptoms when inoculated in compatible hosts. We also conducted an in silico analysis which established the possible network of genes regulated by two-component systems PhoPQ and PhoBR (related to phosphate metabolism), and possible transcriptional factor binding site (TFBS) motifs of regulatory proteins PhoB and PhoP, detaching high degree of conservation of PhoB TFBS in 84 genes of Xac genome. This is the first time that chemotaxis signal transduction and phosphate metabolism were therefore indicated to be fundamental to the process of colonization of plant tissue during the induction of disease associated with Xanthomonas genus bacteria.

  5. Development of a dispatchable PV peak shaving system. Final report on PV:BONUS Phase 2 activities

    Energy Technology Data Exchange (ETDEWEB)

    Ferguson, W.D. [Conectiv, Inc., Wilmington, DE (United States); Nigro, R.M. [Applied Energy Group, Inc., Hauppauge, NY (United States)

    1999-01-20

    In July 1993, the Delmarva Power and Light Company (now Conectiv, Inc.) was awarded a contract for the development of a Dispatchable Photovoltaic Peak Shaving System under the US Department of Energy PV:BONUS Program. The rationale for the dispatchable PV peak shaving system is based on the coincidence between the solar resource and the electrical load in question. Where poor coincidence exists, a PV array by itself does little to offset peak demands. However, with the addition of a relatively small amount of energy storage, the energy from the PV array can be managed and the value of the PV system increases substantially. In Phase 2, Delmarva Power continued the refinement of the system deployed in Phase 1. Four additional dispatchable PV peak shaving systems were installed for extended testing and evaluation at sites in Delaware, Maryland, Wisconsin and North Carolina. A second type of system that can be used to provide back-up power as well as peak shaving was also developed in Phase 2. This PV-UPS system used a packaging approach nearly identical to the PV peak shaving system, although there were significant differences in the design of the power electronics and control systems. Conceptually, the PV-UPS system builds upon the idea of adding value to PV systems by increasing functionality. A prototype of the PV-UPS system was installed in Delaware for evaluation near the end of the contract period.

  6. Energy balance of the global photovoltaic (PV) industry--is the PV industry a net electricity producer?

    Science.gov (United States)

    Dale, Michael; Benson, Sally M

    2013-04-02

    A combination of declining costs and policy measures motivated by greenhouse gas (GHG) emissions reduction and energy security have driven rapid growth in the global installed capacity of solar photovoltaics (PV). This paper develops a number of unique data sets, namely the following: calculation of distribution of global capacity factor for PV deployment; meta-analysis of energy consumption in PV system manufacture and deployment; and documentation of reduction in energetic costs of PV system production. These data are used as input into a new net energy analysis of the global PV industry, as opposed to device level analysis. In addition, the paper introduces a new concept: a model tracking energetic costs of manufacturing and installing PV systems, including balance of system (BOS) components. The model is used to forecast electrical energy requirements to scale up the PV industry and determine the electricity balance of the global PV industry to 2020. Results suggest that the industry was a net consumer of electricity as recently as 2010. However, there is a >50% that in 2012 the PV industry is a net electricity provider and will "pay back" the electrical energy required for its early growth before 2020. Further reducing energetic costs of PV deployment will enable more rapid growth of the PV industry. There is also great potential to increase the capacity factor of PV deployment. These conclusions have a number of implications for R&D and deployment, including the following: monitoring of the energy embodied within PV systems; designing more efficient and durable systems; and deploying PV systems in locations that will achieve high capacity factors.

  7. An Analysis of Open World PvP in LOTRO's PvMP as a Case Study for PvP Games

    Directory of Open Access Journals (Sweden)

    Toh Weimin

    2014-11-01

    Full Text Available This article focuses on the analysis of emergent gameplay, based on a case study of the author's subjective gameplay experience of Player versus Monster Player (PvMP in The Lord of the Rings Online (LOTRO. The argument presented here is that although there is a core system of Player versus Player (PvP which LOTRO shares with other online games, each type of online game has a specific kind of PvP system which attracts players to engage in the gameplay. For instance, the open world sandbox type of PvP attracts certain players to play in LOTRO's PvMP. One of the main aims of this study is thus to investigate some of the core systems of PvP gameplay in open world sandbox PvP. In this article, LOTRO is shown to offer unique opportunities for studying emergent gameplay in open world games, with particular relevance to PvP studies. Two of the core systems of PvP discussed include the design of the simple gameplay rules to support emergent gameplay, and the community's attitudes towards player's behaviours. The types of emergent gameplay discussed include free play versus negotiated fair play, the players' utilisation of strategies in open world PvP to support collaborative and competitive gameplay, and the changing dynamics of open ended gameplay. It is hoped that the analysis provided in this article would form the­ basis of future work on a more general framework for understanding PvP in other online games.

  8. Entomophagous insects associated to Diaphorina citri (Hemiptera: Psyllidae) in citrus orchards with different weed management systems in Papantla, Veracruz, Mexico

    OpenAIRE

    Ortega-Arenas, L. D.; López-López, R.; Lomelí-Flores, J. R.; Cedillo-Portugal, E.; Gómez-Tovar, L.; Salazar-Cruz, J.; Villegas-Monter, A.

    2014-01-01

    Huanglongbing (HLB), one of the most destructive diseases of citrus worldwide, is threatening the survival of the citrus industry in Mexico. Diaphorina citri is the primary vector of HLB; thus, control of the vector it’s vital for disease management. This study was carried out to evaluate the influence of different management systems on the population psyllid density and entomophagous insects associated in orange orchards (Citrus sinensis cv. Valencia) in Papantla, Veracruz, Mexico. Five orch...

  9. Molecular Pathogenesis of NASH

    Directory of Open Access Journals (Sweden)

    Alessandra Caligiuri

    2016-09-01

    Full Text Available Nonalcoholic steatohepatitis (NASH is the main cause of chronic liver disease in the Western world and a major health problem, owing to its close association with obesity, diabetes, and the metabolic syndrome. NASH progression results from numerous events originating within the liver, as well as from signals derived from the adipose tissue and the gastrointestinal tract. In a fraction of NASH patients, disease may progress, eventually leading to advanced fibrosis, cirrhosis and hepatocellular carcinoma. Understanding the mechanisms leading to NASH and its evolution to cirrhosis is critical to identifying effective approaches for the treatment of this condition. In this review, we focus on some of the most recent data reported on the pathogenesis of NASH and its fibrogenic progression, highlighting potential targets for treatment or identification of biomarkers of disease progression.

  10. Pathogenesis of Lassa fever.

    Science.gov (United States)

    Yun, Nadezhda E; Walker, David H

    2012-10-09

    Lassa virus, an Old World arenavirus (family Arenaviridae), is the etiological agent of Lassa fever, a severe human disease that is reported in more than 100,000 patients annually in the endemic regions of West Africa with mortality rates for hospitalized patients varying between 5-10%. Currently, there are no approved vaccines against Lassa fever for use in humans. Here, we review the published literature on the life cycle of Lassa virus with the specific focus put on Lassa fever pathogenesis in humans and relevant animal models. Advancing knowledge significantly improves our understanding of Lassa virus biology, as well as of the mechanisms that allow the virus to evade the host's immune system. However, further investigations are required in order to design improved diagnostic tools, an effective vaccine, and therapeutic agents.

  11. Pathogenesis of Lassa Fever

    Directory of Open Access Journals (Sweden)

    David H. Walker

    2012-10-01

    Full Text Available Lassa virus, an Old World arenavirus (family Arenaviridae, is the etiological agent of Lassa fever, a severe human disease that is reported in more than 100,000 patients annually in the endemic regions of West Africa with mortality rates for hospitalized patients varying between 5-10%. Currently, there are no approved vaccines against Lassa fever for use in humans. Here, we review the published literature on the life cycle of Lassa virus with the specific focus put on Lassa fever pathogenesis in humans and relevant animal models. Advancing knowledge significantly improves our understanding of Lassa virus biology, as well as of the mechanisms that allow the virus to evade the host’s immune system. However, further investigations are required in order to design improved diagnostic tools, an effective vaccine, and therapeutic agents.

  12. Pathogenesis of Takotsubo syndrome

    Directory of Open Access Journals (Sweden)

    Daniele Masarone

    2017-01-01

    Full Text Available Takotsubo syndrome (TTS is an enigmatic disease with a multifactorial and still unresolved pathogenesis. Postulated mechanisms include catecholamine excess, coronary artery spasm, and microvascular dysfunction, however catecholamines seem to play a central role in the pathophysiology of TTS. In facts catecholamines have relevant effects on the vasculature and myocardium. Toxic direct effects of catecholamine on myocardium are mediated by multiple pathway including functional hypoxia, metabolic changes and changes in membrane permeability leading to various electrolytic imbalances. Recently report of familial cases has suggested a genetic component. Further research is required to help clarify the proposed hypotheses and to increase our understanding of the cardiovascular responses to acute stress and the pathophysiology underpinning TTS.

  13. Molecular Pathogenesis of NASH

    Science.gov (United States)

    Caligiuri, Alessandra; Gentilini, Alessandra; Marra, Fabio

    2016-01-01

    Nonalcoholic steatohepatitis (NASH) is the main cause of chronic liver disease in the Western world and a major health problem, owing to its close association with obesity, diabetes, and the metabolic syndrome. NASH progression results from numerous events originating within the liver, as well as from signals derived from the adipose tissue and the gastrointestinal tract. In a fraction of NASH patients, disease may progress, eventually leading to advanced fibrosis, cirrhosis and hepatocellular carcinoma. Understanding the mechanisms leading to NASH and its evolution to cirrhosis is critical to identifying effective approaches for the treatment of this condition. In this review, we focus on some of the most recent data reported on the pathogenesis of NASH and its fibrogenic progression, highlighting potential targets for treatment or identification of biomarkers of disease progression. PMID:27657051

  14. [Pathogenesis of rheumatoid arthritis].

    Science.gov (United States)

    Branimir Anić; Miroslav Mayer

    2014-01-01

    Rheumatoid arthritis (RA) is an autoimmune systemic disease that primarily affects joints. Etiology and the pathogenesis of RA are complex, involving many types of cells, among others macrophages, T and B cells, fibro- blasts, chondrocytes and dendritic cells. Despite well documented role of many genes and epigenetic modifications in the development and evolution of the disease, in most RA patients there is no clear predisposing factor present. Environmental factors involved in RA pathogenesis are cigarette smoke, industrial pollutants like silica crystals, disturbances of intestinal, lung, and oral microbiota and some specific bacterial and viral infectious agents and their components. In the initial disease stage there are qualitative and quantitative disturbances ofpeptide citrulination as well as other protein modifications, followed by antigen presenting cell (APC) (macrophages and dendritic cells) and fibroblast like synoviocytes (FLS) activation. Some microbes foster this processes by APC and FLS direct and indirect activation. In the second stage APC's elicit specific humoral B cell re- sponse resulting in specific antibodies production and T cell autoreactivity. Inherited and acquired defects in T and B cell responses caused by repeated activation of innate immunity as well as loss of tolerance, elicit chronic autoimmune inflammation, primarily of synovial membranes, and development of cellular panus. Pathologic activation of the osteoclasts and release of the immune system effector molecules and the proteolytic enzymes damage the cartilage, bone and tendons composition and structure. Persistent inflammation through its complex mechanisms results in many systemic and extraarticular RA manifestations of almost all organ systems, resulting in severe complications and comorbidities such as rheumatoid lung, carditis, vasculitis, cahexia, anemia, accelerated atherosclerosis, myocardial and cerebrovascular vascular disease, lymphoma, osteoporosis, depression etc

  15. Variation suggestive of horizontal gene transfer at a lipopolysaccharide (lps) biosynthetic locus in Xanthomonas oryzae pv. oryzae, the bacterial leaf blight pathogen of rice

    Science.gov (United States)

    Patil, Prabhu B; Sonti, Ramesh V

    2004-01-01

    Background In animal pathogenic bacteria, horizontal gene transfer events (HGT) have been frequently observed in genomic regions that encode functions involved in biosynthesis of the outer membrane located lipopolysaccharide (LPS). As a result, different strains of the same pathogen can have substantially different lps biosynthetic gene clusters. Since LPS is highly antigenic, the variation at lps loci is attributed to be of advantage in evading the host immune system. Although LPS has been suggested as a potentiator of plant defense responses, interstrain variation at lps biosynthetic gene clusters has not been reported for any plant pathogenic bacterium. Results We report here the complete sequence of a 12.2 kb virulence locus of Xanthomonas oryzae pv. oryzae (Xoo) encoding six genes whose products are homologous to functions involved in LPS biosynthesis and transport. All six open reading frames (ORFs) have atypical G+C content and altered codon usage, which are the hallmarks of genomic islands that are acquired by horizontal gene transfer. The lps locus is flanked by highly conserved genes, metB and etfA, respectively encoding cystathionine gamma lyase and electron transport flavoprotein. Interestingly, two different sets of lps genes are present at this locus in the plant pathogens, Xanthomonas campestris pv. campestris (Xcc) and Xanthomonas axonopodis pv. citri (Xac). The genomic island is present in a number of Xoo strains from India and other Asian countries but is not present in two strains, one from India (BXO8) and another from Nepal (Nepal624) as well as the closely related rice pathogen, Xanthomonas oryzae pv. oryzicola (Xoor). TAIL-PCR analysis indicates that sequences related to Xac are present at the lps locus in both BXO8 and Nepal624. The Xoor strain has a hybrid lps gene cluster, with sequences at the metB and etfA ends, being most closely related to sequences from Xac and the tomato pathogen, Pseudomonas syringae pv. tomato respectively

  16. Numerical study of PV/T-SAHP system

    Institute of Scientific and Technical Information of China (English)

    Gang PEI; Jie JI; Ke-liang LIU; Han-feng HE; Ai-guo JIANG

    2008-01-01

    In order to utilize solar energy effectively and to achieve a higher electrical efficiency by limiting the operating temperature of the photovoltaic (PV) panel, a novel photovoltaic/thermal solar-assisted heat pump (PV/T-SAHP) system was proposed and constructed. The hybrid solar system generates electricity and thermal energy simultaneously. A distributed parameters model of the PV/T-SAHP system was developed and applied to analyze the system dynamic performance in terms of PV action, photothermal action and Rankine cycle processes. The simulation results indicated that the coefficient of performance (COP) of the proposed PV/T-SAHP can be much better than that of the conventional heat pump. Both PV-efficiency and photothermic efficiency have been improved considerably. The results also showed that the performance of this PV/T-SAHP system was strongly influenced by the evaporator area, tube pitch and tilt angle of the PV/T evaporator, which are the key factors in PV/T-SAHP system optimization and PV/T evaporator design.

  17. β-caryophyllene emitted from a transgenic Arabidopsis or chemical dispenser repels Diaphorina citri, vector of Candidatus Liberibacters.

    Science.gov (United States)

    Alquézar, Berta; Volpe, Haroldo Xavier Linhares; Magnani, Rodrigo Facchini; de Miranda, Marcelo Pedreira; Santos, Mateus Almeida; Wulff, Nelson Arno; Bento, Jose Mauricio Simões; Parra, José Roberto Postali; Bouwmeester, Harro; Peña, Leandro

    2017-07-17

    Production of citrus, the main fruit tree crop worldwide, is severely threatened by Huanglongbing (HLB), for which as yet a cure is not available. Spread of this bacterial disease in America and Asia is intimately connected with dispersal and feeding of the insect vector Diaphorina citri, oligophagous on rutaceous host plants. Effective control of this psyllid is an important component in successful HLB management programs. Volatiles released from the non-host guava have been shown to be repellent to the psyllid and to inhibit its response to citrus odour. By analysing VOC emission from guava we identified one volatile compound, (E)-β-caryophyllene, which at certain doses exerts a repellent effect on D. citri. Non-host plant rejection mediated by (E)-β-caryophyllene is demonstrated here by using Arabidopsis over-expression and knock-out lines. For the first time, results indicate that genetically engineered Arabidopsis plants with modified emission of VOCs can alter the behaviour of D. citri. This study shows that transgenic plants with an inherent ability to release (E)-β-caryophyllene can potentially be used in new protection strategies of citrus trees against HLB.

  18. GENETIC Diaphorina citri DIVERSITY ON CITRUS CROPS OF THE VALLE DEL CAUCA AND QUINDÍO (COLOMBIA

    Directory of Open Access Journals (Sweden)

    MIGUEL ANGEL MONCAYO-DONOSO

    2014-07-01

    Full Text Available The Asiatic psyllid Diaphorina citri (Hemiptera: Psyllidae is the main vector of Candidatus liberibacter, which causes the Huanglongbing HLB disease, known for devastating citrus in the world but not yet reported in Colombia. The genetic variability of the D. citri population was studied through sequencing the COI mitochondrial gene as molecular marker. Adults were collected in citrus producing zones of the Colombian Valle del Cauca and Quindío. Amplification was performed with two pairs of specific primers for Hemiptera. The PCR products were sequenced at Macrogen-Korea, obtaining a total of 124 sequences. For the bioinformatic analysis, the Vector NTI 11.5, Harlequin V 3.5, MEGA 5 and MAFFT 6 programs were used. The molecular diversity indices between populations were similar, revealing a common origin and a recent split of the populations excluding a significant genetic differentiation associated to variations of the bacterium, however the haplotype diversity index was higher than the nucleotide diversity index. The latter one showed a low number of polymorphic sites, indicating that the D. citri populations are expanding. The study of the vector’s genetic variability is a tool for the prediction of likely scenarios for the spread of diseases.

  19. Essential Oil Variation from Twenty Two Genotypes of Citrus in Brazil—Chemometric Approach and Repellency Against Diaphorina citri Kuwayama

    Directory of Open Access Journals (Sweden)

    Moacir dos Santos Andrade

    2016-06-01

    Full Text Available The chemical composition of volatile oils from 22 genotypes of Citrus and related genera was poorly differentiated, but chemometric techniques have clarified the relationships between the 22 genotypes, and allowed us to understand their resistance to D. citri. The most convincing similarities include the synthesis of (Z-β-ocimene and (E-caryophyllene for all 11 genotypes of group A. Genotypes of group B are not uniformly characterized by essential oil compounds. When stimulated with odor sources of 22 genotypes in a Y-tube olfactometer D. citri preferentially entered the arm containing the volatile oils of Murraya paniculata, confirming orange jasmine as its best host. C. reticulata × C. sinensis was the least preferred genotype, and is characterized by the presence of phytol, (Z-β-ocimene, and β-elemene, which were not found in the most preferred genotype. We speculate that these three compounds may act as a repellent, making these oils less attractive to D. citri.

  20. De novo characterization of the Dialeurodes citri transcriptome: mining genes involved in stress resistance and simple sequence repeats (SSRs) discovery.

    Science.gov (United States)

    Chen, E-H; Wei, D-D; Shen, G-M; Yuan, G-R; Bai, P-P; Wang, J-J

    2014-02-01

    The citrus whitefly, Dialeurodes citri (Ashmead), is one of the three economically important whitefly species that infest citrus plants around the world; however, limited genetic research has been focused on D. citri, partly because of lack of genomic resources. In this study, we performed de novo assembly of a transcriptome using Illumina paired-end sequencing technology (Illumina Inc., San Diego, CA, USA). In total, 36,766 unigenes with a mean length of 497 bp were identified. Of these unigenes, we identified 17,788 matched known proteins in the National Center for Biotechnology Information database, as determined by Blast search, with 5731, 4850 and 14,441 unigenes assigned to clusters of orthologous groups (COG), gene ontology (GO), and SwissProt, respectively. In total, 7507 unigenes were assigned to 308 known pathways. In-depth analysis of the data showed that 117 unigenes were identified as potentially involved in the detoxification of xenobiotics and 67 heat shock protein (Hsp) genes were associated with environmental stress. In addition, these enzymes were searched against the GO and COG database, and the results showed that the three major detoxification enzymes and Hsps were classified into 18 and 3, 6, and 8 annotations, respectively. In addition, 149 simple sequence repeats were detected. The results facilitate the investigation of molecular resistance mechanisms to insecticides and environmental stress, and contribute to molecular marker development. The findings greatly improve our genetic understanding of D. citri, and lay the foundation for future functional genomics studies on this species.

  1. PV solar electricity: status and future

    Science.gov (United States)

    Hoffmann, Winfried

    2006-04-01

    Within the four main market segments of PV solar electricity there are already three areas competitive today. These are off-grid industrial and rural as well as consumer applications. The overall growth within the past 8 years was almost 40 % p.a. with a "normal" growth of about 18 % p.a. for the first three market segments whereas the grid connected market increased with an astonishing 63 % p.a. The different growth rates catapulted the contribution of grid connected systems in relation to the total market from about one quarter 6 years ago towards more than three quarters today. The reason for this development is basically due to industry-politically induced market support programs in the aforementioned countries. It is quite important to outline under which boundary conditions grid connected systems will be competitive without support programs like the feed in tariff system in Germany, Spain and some more to come in Europe as well as investment subsidies in Japan, US and some other countries. It will be shown that in a more and more liberalized utility market worldwide electricity produced by PV solar electricity systems will be able to compete with their generating cost against peak power prices from utilities. The point of time for this competitiveness is mainly determined by the following facts: 1. Price decrease for PV solar electricity systems leading to an equivalent decrease in the generated cost for PV produced kWh. 2. Development of a truly liberalized electricity market. 3. Degree of irradiation between times of peak power demand and delivery of PV electricity. The first topic is discussed using price experience curves. Some explanations will be given to correlate the qualitative number of 20 % price decrease for doubling cumulative worldwide sales derived from the historic price experience curve with a more quantitative analysis based on our EPIA-Roadmap (productivity increase and ongoing improvements for existing technologies as well as development

  2. Parallel experimental study of a novel super-thin thermal absorber based photovoltaic/thermal (PV/T) system against conventional photovoltaic (PV) system

    OpenAIRE

    2015-01-01

    Photovoltaic (PV) semiconductor degrades in performance due to temperature rise. A super thin-conductive thermal absorber is therefore developed to regulate the PV working temperature by retrofitting the existing PV panel into the photovoltaic/thermal (PV/T) panel. This article presented the parallel comparative investigation of the two different systems through both laboratory and field experiments. The laboratory evaluation consisted of one PV panel and one PV/T panel respectively while the...

  3. PV/T slates - Application examples and case studies; PV/T-Schiefer. Anwendungsbeispiele und Fallstudien

    Energy Technology Data Exchange (ETDEWEB)

    Kropf, S.

    2003-07-01

    This illustrated report for the Swiss Federal Office of Energy (SFOE) is one a series of five reports dealing with increasing the overall efficiency of photovoltaic (PV) installations by also using the heat collected by the dark-coloured PV panels. The work reported on addresses open questions on the use of the heat and its optimal use. This report presents possible applications for PV/T slates based on data from the production atlas presented in another report in this series. Application variants are discussed, including hot-water preparation, air pre-heating, air-water heat pumps, buried seasonal storage and latent seasonal heat storage. Detailed examples are given for a hotel in Lugano, Switzerland and a residential estate in Davos.

  4. PV shading device integrated system in a University Building in Italy

    OpenAIRE

    2004-01-01

    PV Enlargement project PV Enlargement" boldly demonstrates Europe’s commitment for improved energy efficiency and cost-effectiveness of PV systems, enhancing the development of large European PV markets. The project can be subdivided into three major fields of activities: Demonstration (1,218 kWp) of highly cost-effective or very innovative PV technologies in 10 European countries for increasing public awareness about and visibility of PV solar electricity Transfer of PV Technol...

  5. PV/T slates - Production atlas; PV/T-Schiefer. Ertragsatlas

    Energy Technology Data Exchange (ETDEWEB)

    Kropf, S.

    2003-07-01

    This illustrated report for the Swiss Federal Office of Energy (SFOE) is one a series of five reports dealing with increasing the overall efficiency of photovoltaic (PV) installations by also using the heat collected by the dark-coloured PV panels. The work reported on addresses open questions on the use of the heat and its optimal use. This report first deals with the dynamic building simulation system IDA and goes on to present an appendix that lists the results for the three climatic locations Zurich, Lugano and Davos in detail. The results are calculated for various seasons, orientations, mounting angles, air-flow rates and temperature differences.

  6. Sobre o condicionamento alimentar na cochonilha-branca, Planococcus citri (Risso (Hemiptera: pseudococcidae Regarding to host conditioning in citrus mealybug Planococcus citri (Risso (Hemiptera: pseudococcidae

    Directory of Open Access Journals (Sweden)

    Lenira Viana Costa Santa-Cecília

    2013-03-01

    Full Text Available Estudos do comportamento alimentar mediante a técnica de "Electrical Penetration Graphs" (EPG das cochonilhas-farinhentas (Pseudococcidae provenientes de um hospedeiro de criação alternativo têm mostrado que esses insetos não atingem ou demoram cerca de 9 horas para alcançar a fase floemática. Por outro lado, aqueles provenientes do hospedeiro-fonte atingem a fase floemática mais rapidamente e apresentam maior frequência de alimentação nos vasos crivados. Esses resultados indicam a presença do fenômeno de condicionamento alimentar, ainda não demonstrado em cochonilhas. Assim, o presente trabalho teve como objetivo determinar a existência desse fenômeno em Planococcus citri (Risso (Hemiptera: Pseudococcidae. Foram realizados testes de livre escolha, monitoramento eletrônico (EPG e estudos de alguns parâmetros biológicos. Em todos os experimentos, o cafeeiro (Coffea arabica L., os citros (Citrus sinensis L. e abóbora (Cucurbita maxima L. foram utilizados como substratos de criação (fonte da cochonilha, sendo os tratamentos constituídos pela combinação entre os hospedeiros-fonte e os hospedeiros receptores (café e citros. O teste de escolha entre cafeeiro e citros nas primeiras 72 horas mostrou que as cochonilhas criadas em cafeeiro apresentaram preferência pelo cafeeiro; aquelas originadas dos citros mostraram uma tendência, embora não significativa, em selecionar os citros em relação ao cafeeiro e aquelas criadas em abóbora não mostraram preferência por nenhum dos hospedeiros. Os estudos do comportamento alimentar mediante o monitoramento eletrônico (EPG mostraram que a fase floemática, considerada como a fase de aceitação do hospedeiro, foi mais frequente em cafeeiro, seja com cochonilhas oriundas deste substrato, seja de citros. Aqueles insetos mantidos em abóbora e transferidos para o cafeeiro ou citros apresentaram excepcionalmente ou não apresentaram nenhuma fase floemática, respectivamente. A

  7. Testing to Support Improvements to PV Components and Systems

    Energy Technology Data Exchange (ETDEWEB)

    THOMAS,H.; KROPOSKI,B.; WITT,C.; BOWER,WARD I.; BONN,RUSSELL H.; GINN,JERRY W.; GONZALEZ,SIGIFREDO

    2000-07-15

    The National Photovoltaic (PV) Program is sponsored by the US Department of Energy and includes a PV Manufacturing Research and Development (R and D) project conducted with industry. This project includes advancements in PV components to improve reliability, reduce costs, and develop integrated PV systems. Participants submit prototypes, pre-production hardware products, and examples of the resulting final products for a range of tests conducted at several national laboratories, independent testing laboratories, and recognized listing agencies. The purpose of this testing is to use the results to assist industry in determining a product's performance and reliability, and to identify areas for potential improvement. This paper briefly describes the PV Manufacturing R and D project, participants in the area of PV systems, balance of systems, and components, and several examples of the different types of product and performance testing used to support and confirm product performance.

  8. PV technology and success of solar electricity in Vietnam

    Energy Technology Data Exchange (ETDEWEB)

    Dung, T.Q. [Vietnam National Center for Science and Technology, Ho Chi Minh City (Viet Nam). Solarlab

    1997-12-31

    Since 1990 the PV Technology and the Solar electricity have been strongly developed in Vietnam. The PV experts of Solarlab have studied and set up an appropriate PV Technology responding to local Market needs. It has not only stood well but has been also transferred to Mali Republic and Lao P.D.R. The PV off grid systems of Solarlab demonstrate good efficiency and low prices. Over 60 solar stations and villages have been built to provide solar lighting for about 3000 families along the country in remote, mountainous areas and islands. 400 families are using stand-alone Solar Home Systems. The Solar electricity has been chosen for Rural Electrification and National Telecommunication Network in remote and mountainous regions. Many International projects in cooperation with FONDEM-France, SELF USA and Governmental PV projects have been realized by Solarlab. The experiences of maintenance, management and finance about PV development in Vietnam are also mentioned.

  9. Pathogenesis of bone metastasis

    Directory of Open Access Journals (Sweden)

    Erdinc Nayir

    2016-01-01

    Full Text Available Bone metastases are more frequently seen as a complication of cancer than primary bone tumors. For example, it can be seen in as many as 70% of advanced stage breast and prostate cancer cases. Metastatic bone disease is generally categorized as osteoblastic, and osteolytic disease. However most of the cancer types demonstrate a wide spectrum between these two extremes. Paracrine interaction between parathyroid hormone–related protein (PTHrP which increases the rate of bone osteolysis, and transforming growth factor-β (TGF-β plays a role in osteolytic metastasis. Increased local bone PTHrP concentration increases expression of receptor activator of nuclear factor kappa-B ligand (RANKL with resultant activation of osteoclastogenesis. Endothelin – 1 (ET-1, and dickkopf homolog -1 (DKK-1 produced by tumor involve in osteoblastic metastasis. DKK-1 is the central regulator of osteoblastic activity, and osteoblastic bone metastasis. For the elaboration of treatment strategies against frequently seen complication, that is, bone metastases, targets involving in pathogenesis of these complications should be taken into consideration.

  10. PV window - Development and demonstrations. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Haugaard, P.

    2011-05-15

    Using the results from the EU project RenewTransnet, which focused on the development of a pane with integrated solar cells, the goal of this project is to develop these principles into a window solution. This window solution is targeted to Danish building tradition and architecture. It is expected that an elegant PV-window solution for both new and retrofit buildings is developed during this project, and which appearance can be customized to each building. Based on results from a related projects carried out by Gaia Solar, the window solution will have the potential of being approximately 30% cheaper than similar products on the market. In this project this price reduction is the objective of the development of a window solution. The project team has succeeded in developing a 2-layer PV-window with glass / glass lamination with EVA as foil, which is 35% cheaper than similar products on the market. Since the price for the frame-profile does not differ significantly at market level, the price comparison is made on the basis of the developed PV-pane. The objective of 30 % price reduction in relation to similar products on the market is met. A special production process to the making glass/glass lamination with EVA as foil has been developed, in which a frame is put around the module which intends both to remove the unwanted tension along the edges, and to prevent the significant spillage of EVA from the module under pressure and prevent the invasive bubbles along the edge of module. Since the developed production method for making glass/glass modules with EVA is simple, a further cost reduction will primarily be in a reduction of the price of the cell. The project process has resulted in the development of a product, which due to continuous restrictions in the building regulations, will be very attractive in future buildings. (LN)

  11. PV modules without bypass diodes; PV-Module ohne Bypass-Dioden? - Untersuchungen an einer PV-Fassade

    Energy Technology Data Exchange (ETDEWEB)

    Laukamp, H.; Kresse, A.; Leithold, W. [Fraunhofer-Institut fuer Solare Energiesysteme (ISE), Freiburg im Breisgau (Germany)]|[Ingenieurbuero A. Kresse, Karlsruhe (Germany)]|[Solare Systemtechnik GmbH, Freiburg (Germany)

    1998-12-01

    In order to protect solar modules against high output losses with non-homogeneous irradiation, bypass diodes which are mostly accommodated in the module connection socket are used. One would often gladly dispense with these connection sockets for integration of customer-specific large modules in facades. The question: ``Where will the diodes go?`` must then be satisfactorily answered. Both laminating the diodes in the module and their external accommodation cause extra expense elsewhere. It would be ideal if one could dispense with the bypass diodes altogether. This article tries to answer the question, in what conditions this is possible. Starting from the PV facade `Freiburg solar centre`, where one dispensed with the protective diodes, investigations are carried out experimentally and by means of simulation calculations. [Deutsch] Um Solarmodule bei inhomogener Bestrahlung vor hohen Verlustleistungen zu schuetzen, werden ueblicherweise Bypass-Dioden eingesetzt, die zumeist in der Modulanschlussdose untergebracht sind. Zur Fassadenintegration von kundenspezifischen Grossmodulen wuerde man manchmal gerne auf die Anschlussdosen verzichten. Hierfuer muesste zunaechst die Frage `wohin mit den Dioden?` befriedigend beantwortet werden. Sowohl die Einlaminierung der Dioden in das Modul, als auch deren externe Unterbringung versursachen an anderer Stelle einen erhoehten Aufwand. Ideal waere es, wenn man auf die Bypass-Dioden ganz verzichten koennte. Die vorliegende Arbeit versucht die Frage zu beantworten, unter welchen Bedingungen dies moeglich ist. Ausgehend von der PV-Fassade `Solarzentrum Freiburg` - hier wurde auf den Einsatz von Schutzdioden verzichtet - werden experimentell und mittels Simulationsrechnungen Untersuchungen durchgefuehrt. (orig./RHM)

  12. Impact of Rooftop Solar PV on Residential Distribution Network

    DEFF Research Database (Denmark)

    Bhattarai, Bishnu Prasad; Bak-Jensen, Birgitte; Pillai, Jayakrishnan Radhakrishna

    Increased environmental awareness in recent years has encouraged rapid growth of renewable energy sources especially solar PV and wind. Among them, small scale solar PV has been gaining more momentum especially at residential level. Even today moderate penetration of grid tied rooftop solar PV has...... become reality in many countries. In spite of various benefits, higher penetration of rooftop PVs might come up with number of detrimental effects, with power quality and overcurrent protection being the major ones. Therefore, it is reasonable to quantify both drawback and benefits of rooftop PV...

  13. Solar Energy: Incentives to Promote PV in EU27

    Directory of Open Access Journals (Sweden)

    María del P. Pablo-Romero

    2013-11-01

    Full Text Available The growth in the use of renewable energies in the EU has been remarkable. Among these energies is PV. The average annual growth rate for the EU-27 countries in installed PV capacity in the period 2005-2012 was 41.2%. While the installed capacity of PV has reached almost 82 % of National Renewable Energy Action Plan (NREAP targets for the EU-27 countries for 2020, it is still far from being used at its full potential. Over recent years, several measures have been adopted in the EU to enhance and promote PV. This paper undertakes a complete review of the state of PV power in Europe and the measures taken to date to promote it in EU-27. 25 countries have adopted measures to promote PV. The most widespread measure to promote PV use is Feed- in Tariffs. Tariffs are normally adjusted, in a decreasing manner, annually. Nevertheless, currently, seven countries have decided to accelerate this decrease rate in view of cost reduction of the installations and of higher efficiencies. The second instrument used to promote PV in the EU-27 countries is the concession of subsidies. Nevertheless, subsidies have the disadvantage of being closely linked to budgetary resources and therefore to budgetary constraints. In most EU countries, subsidies for renewable energy for PV are being lowered. Twelve EU-27 countries adopted tax measures. Low-interest loans and green certificate systems were only sparingly used.

  14. Fault Analysis and Detection in Microgrids with High PV Penetration

    Energy Technology Data Exchange (ETDEWEB)

    El Khatib, Mohamed [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hernandez Alvidrez, Javier [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ellis, Abraham [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-05-01

    In this report we focus on analyzing current-controlled PV inverters behaviour under faults in order to develop fault detection schemes for microgrids with high PV penetration. Inverter model suitable for steady state fault studies is presented and the impact of PV inverters on two protection elements is analyzed. The studied protection elements are superimposed quantities based directional element and negative sequence directional element. Additionally, several non-overcurrent fault detection schemes are discussed in this report for microgrids with high PV penetration. A detailed time-domain simulation study is presented to assess the performance of the presented fault detection schemes under different microgrid modes of operation.

  15. Evaluation of a solar PV tracking prototype on tropic regions

    Directory of Open Access Journals (Sweden)

    Cristian Manuel Agudelo Restrepo

    2016-06-01

    Full Text Available Nowadays climate change is a big concern for human society, due to our high dependence on fossil fuels. A great amount of research effort is focused in solar photovoltaic (PV systems, particularly on the improvement of the conversion efficiency. One technique commonly used is the tracking systems, where the solar PV moves with the sun in order to capture the maximum direct solar radiation. This paper presents a solar PV single-axis tracking system prototype, and a comparison regarding its energy conversion efficiency with a fixed solar PV installation. The system was tested in Fusagasugá, Colombia, which is located in the tropics region.

  16. Integrating Solar PV in Utility System Operations

    Energy Technology Data Exchange (ETDEWEB)

    Mills, A.; Botterud, A.; Wu, J.; Zhou, Z.; Hodge, B-M.; Heany, M.

    2013-10-31

    This study develops a systematic framework for estimating the increase in operating costs due to uncertainty and variability in renewable resources, uses the framework to quantify the integration costs associated with sub-hourly solar power variability and uncertainty, and shows how changes in system operations may affect these costs. Toward this end, we present a statistical method for estimating the required balancing reserves to maintain system reliability along with a model for commitment and dispatch of the portfolio of thermal and renewable resources at different stages of system operations. We estimate the costs of sub-hourly solar variability, short-term forecast errors, and day-ahead (DA) forecast errors as the difference in production costs between a case with “realistic” PV (i.e., subhourly solar variability and uncertainty are fully included in the modeling) and a case with “well behaved” PV (i.e., PV is assumed to have no sub-hourly variability and can be perfectly forecasted). In addition, we highlight current practices that allow utilities to compensate for the issues encountered at the sub-hourly time frame with increased levels of PV penetration. In this analysis we use the analytical framework to simulate utility operations with increasing deployment of PV in a case study of Arizona Public Service Company (APS), a utility in the southwestern United States. In our analysis, we focus on three processes that are important in understanding the management of PV variability and uncertainty in power system operations. First, we represent the decisions made the day before the operating day through a DA commitment model that relies on imperfect DA forecasts of load and wind as well as PV generation. Second, we represent the decisions made by schedulers in the operating day through hour-ahead (HA) scheduling. Peaking units can be committed or decommitted in the HA schedules and online units can be redispatched using forecasts that are improved

  17. A minimum achievable PV electrical generating cost

    Energy Technology Data Exchange (ETDEWEB)

    Sabisky, E.S. [11 Carnation Place, Lawrenceville, NJ 08648 (United States)

    1996-03-22

    The role and share of photovoltaic (PV) generated electricity in our nation`s future energy arsenal is primarily dependent on its future production cost. This paper provides a framework for obtaining a minimum achievable electrical generating cost (a lower bound) for fixed, flat-plate photovoltaic systems. A cost of 2.8 $cent/kWh (1990$) was derived for a plant located in Southwestern USA sunshine using a cost of money of 8%. In addition, a value of 22 $cent/Wp (1990$) was estimated as a minimum module manufacturing cost/price

  18. Ancillary services provided by PV power plants

    Directory of Open Access Journals (Sweden)

    Antonio PIERNO

    2016-07-01

    Full Text Available Renewable energy sources are widely utilized in distributed generation systems, and, recently, they are also considered for providing ancillary services. The paper is focused on PV plants, a survey of the most interesting papers published in the literature in the last decade is reported and the main characteristics of the technical proposals, with their advantages and limits, are evidenced. The results are schematically shown in a table that immediately gives the opportunity to be aware of what was already done, representing a reference tool.

  19. Integrating Solar PV in Utility System Operations

    Energy Technology Data Exchange (ETDEWEB)

    Mills, A.; Botterud, A.; Wu, J.; Zhou, Z.; Hodge, B-M.; Heany, M.

    2013-10-31

    This study develops a systematic framework for estimating the increase in operating costs due to uncertainty and variability in renewable resources, uses the framework to quantify the integration costs associated with sub-hourly solar power variability and uncertainty, and shows how changes in system operations may affect these costs. Toward this end, we present a statistical method for estimating the required balancing reserves to maintain system reliability along with a model for commitment and dispatch of the portfolio of thermal and renewable resources at different stages of system operations. We estimate the costs of sub-hourly solar variability, short-term forecast errors, and day-ahead (DA) forecast errors as the difference in production costs between a case with “realistic” PV (i.e., subhourly solar variability and uncertainty are fully included in the modeling) and a case with “well behaved” PV (i.e., PV is assumed to have no sub-hourly variability and can be perfectly forecasted). In addition, we highlight current practices that allow utilities to compensate for the issues encountered at the sub-hourly time frame with increased levels of PV penetration. In this analysis we use the analytical framework to simulate utility operations with increasing deployment of PV in a case study of Arizona Public Service Company (APS), a utility in the southwestern United States. In our analysis, we focus on three processes that are important in understanding the management of PV variability and uncertainty in power system operations. First, we represent the decisions made the day before the operating day through a DA commitment model that relies on imperfect DA forecasts of load and wind as well as PV generation. Second, we represent the decisions made by schedulers in the operating day through hour-ahead (HA) scheduling. Peaking units can be committed or decommitted in the HA schedules and online units can be redispatched using forecasts that are improved

  20. Recent progress in melasma pathogenesis.

    Science.gov (United States)

    Lee, Ai-Young

    2015-11-01

    Melasma is a common skin pigmentation condition. Given therapeutic difficulty as one of the biggest concerns, understanding of the etiology and pathogenesis of melasma becomes essential. UV irradiation, female sex hormones, and inflammatory processes are addressed as triggering factors with genetic predisposition. The mechanism of UV-induced melanogenesis has been extensively investigated as a model system to study melasma pathogenesis. Hitherto, treatment modalities for melasma are similar to other hyperpigmentation disorders. However, individual triggering factors induce a separate pigmentation disease, whose pathogenic mechanisms and clinical phenotypes are different from the ones encountered in melasma. Fortunately, there have been ongoing updates on melasma pathogenesis with regard to major triggering factors. Presence of certain factors working independently of UV exposure and role of dermal factors and microRNAs are being identified as novel discoveries about melasma pathogenesis. In this review, the melasma pathogenesis is reviewed in association with updated and new findings.

  1. Experimental investigation of PV modules recycling; PV module recycle no jikkenteki kento

    Energy Technology Data Exchange (ETDEWEB)

    Unagida, H.; Kurokawa, K. [Tokyo University of Agriculture and Technology, Tokyo (Japan); Sakuta, K.; Otani, K.; Murata, K. [Electrotechnical Laboratory, Tsukuba (Japan)

    1997-11-25

    Recycling, cost/energy analysis and recovery experiment were made on crystalline silicon PV modules with EVA(ethylene vinyl acetate)-laminated structure. The life of modules is dependent not on performance deterioration of PV cells themselves but on yellowing or poor transmittance of EVA caused by ultraviolet ray, and disconnection between cells by thermal stress. Recovery is carried out in 3 stages of cell, wafer and material. Recovery in the stages of cell and wafer results in considerable reduction of energy and cost. The recovery experiment was carried out using PV module samples prepared by cutting the modules into 25times15mm pieces after removing Al frames from the used modules, peeling back sheets and cutting off EVA. Since a nitric acid process at 70-80degC can dissolve EVA effectively, it is promising for reuse of surface glass and PV cells as they are. This process is also carried out under a condition around room temperature and pressure, contributing to cost reduction and energy saving for recycling. Generation of harmful NOx is only a problem to be solved. 2 refs., 6 figs., 1 tab.

  2. Development of a Dispatchable PV Peak Shainv System. PV: Bonus Program - Phase 1 Report. Volume 1

    Energy Technology Data Exchange (ETDEWEB)

    None

    1995-10-01

    This report summarizes the work performed by Delmarva Power and Light and its subcontractors in Phase 1 of the US Department of Energy's PV:BONUS Program. The purpose of the program is to develop products and systems for buildings which utilize photovoltaic (N) technology. Beginning with a cooperative research effort with the University of Delaware's Center for Energy and Environmental Policy Research Delmarva Power developed and demonstrated the concept of Dispatchable PV Peak Shaving. This concept and the system which resulted horn the development work are unique from other grid-connected PV systems because it combines a PV, battery energy storage, power conversion and control technologies into an integrated package. Phase 1 began in July 1993 with the installation of a test and demonstration system at Delmarva's Northern Division General Office building near Newark, Delaware. Following initial testing throughout the summer and fall of 1993, significant modifications were made under an amendment to the DOE contract. Work on Phase 1 concluded in the early spring of 1995. Significant progress towards the goal of commercializing the system was made during Phase 1, and is summarized. Based on progress in Phase 1, a proposal to continue the work in Phase 2 was submitted to the US DOE in May 1995. A contract amendment and providing funds for the Phase 2 work is expected in July 1995.

  3. New advances in the pathogenesis and therapy of essential thrombocythemia.

    Science.gov (United States)

    Levine, Ross L; Heaney, Mark

    2008-01-01

    Essential thrombocythemia (ET) is a hematopoietic disorder that manifests clinically as thrombocytosis, and patients with ET are at increased risk for developing thrombosis, myelofibrosis, and transformation to acute myeloid leukemia. Although ET was recognized as a distinct clinical syndrome more than 6 decades ago and was classified as a myeloproliferative neoplasm (MPN) by William Dameshek in 1951, the molecular pathogenesis of ET remained unknown until 2005, when activating mutations in the JAK2 tyrosine kinase (JAK2V617F) were identified in a significant proportion of patients with ET, polycythemia vera (PV) and primary myelofibrosis (PMF). In addition, subsequent studies have identified gain-of-function mutations in the thrombopoietin receptor (MPL) in a subset of patients with JAK2V617F-negative ET, suggesting that JAK2 activation by distinct mechanisms contributes to the pathogenesis of ET. Despite these important observations, important questions remain regarding the role of JAK2/MPL mutations in ET pathogenesis, the etiology of JAK2/MPL negative ET, the factors that distinguish ET from other MPNs with the JAK2V617F mutation, and the role of JAK2-targeted therapies for the treatment of these MPNs.

  4. Simulation of Power Produced by a Building Added PV System in Indonesia using virtual reality

    NARCIS (Netherlands)

    Veldhuis, A.J.; Reinders, A.H.M.E.

    2014-01-01

    In this study a PV system will be simulated using virtual reality software for PV system simulations -called VR4PV - to show the effectiveness of the modelling of PV systems on buildings which are placed in the tropics. The PV system used for this study has been installed in Papua, Indonesia and inc

  5. Antennal and Abdominal Transcriptomes Reveal Chemosensory Genes in the Asian Citrus Psyllid, Diaphorina citri.

    Directory of Open Access Journals (Sweden)

    Zhongzhen Wu

    Full Text Available The Asian citrus psyllid, Diaphorina citri is the principal vector of the highly destructive citrus disease called Huanglongbing (HLB or citrus greening, which is a major threat to citrus cultivation worldwide. More effective pest control strategies against this pest entail the identification of potential chemosensory proteins that could be used in the development of attractants or repellents. However, the molecular basis of olfaction in the Asian citrus psyllid is not completely understood. Therefore, we performed this study to analyze the antennal and abdominal transcriptome of the Asian citrus psyllid. We identified a large number of transcripts belonging to nine chemoreception-related gene families and compared their expression in male and female adult antennae and terminal abdomen. In total, 9 odorant binding proteins (OBPs, 12 chemosensory proteins (CSPs, 46 odorant receptors (ORs, 20 gustatory receptors (GRs, 35 ionotropic receptors (IRs, 4 sensory neuron membrane proteins (SNMPs and 4 different gene families encoding odorant-degrading enzymes (ODEs: 80 cytochrome P450s (CYPs, 12 esterase (ESTs, and 5 aldehyde dehydrogenases (ADE were annotated in the D. citri antennal and abdominal transcriptomes. Our results revealed that a large proportion of chemosensory genes exhibited no distinct differences in their expression patterns in the antennae and terminal abdominal tissues. Notably, RNA sequencing (RNA-seq data and quantitative real time-PCR (qPCR analyses showed that 4 DictOBPs, 4 DictCSPs, 4 DictIRs, 1 DictSNMP, and 2 DictCYPs were upregulated in the antennae relative to that in terminal abdominal tissues. Furthermore, 2 DictOBPs (DictOBP8 and DictOBP9, 2 DictCSPs (DictOBP8 and DictOBP12, 4 DictIRs (DictIR3, DictIR6, DictIR10, and DictIR35, and 1 DictCYP (DictCYP57 were expressed at higher levels in the male antennae than in the female antennae. Our study provides the first insights into the molecular basis of chemoreception in this

  6. Projecting of PV facades in consideration of PV-specific operating conditions; Besonderheiten bei der Projektierung von Photovoltaik-Fassadenanlagen

    Energy Technology Data Exchange (ETDEWEB)

    Decker, B.; Grimmig, B.; Mencke, D. [Institut fuer Solarenergieforschung GmbH Hameln/Emmerthal (ISFH), Emmerthal (Germany). Gruppe Photovoltaik-Systeme; Stellbogen, D. [Zentrum fuer Sonnenenergie- und Wasserstoff-Forschung Baden-Wuerttemberg (ZSW), Stuttgart (Germany). Fachgebiet Photovoltaische Anlagentechnik

    1998-02-01

    PV facades can provide several additional functions such as weather protection, thermal insulation, daylighting or sun protection. On the other hand, specific operating conditions for PV facades must be taken into account when selecting components and designing the system. Depending on ventilation conditions, there is a large range of maximum module temperatures. South-oriented PV facades receive about 30% less yearly irradiation than an optimally inclined PV generator, hence reflection losses are approximately 4% higher. The maximum of yearly irradiation lies only in the 400-600 W/m{sup 2} range. Surrounding buildings and/or vegetation can impair performance of the PV-facades. For a south-oriented PV facade an annual yield in the range of 470-560 kwh/kW{sub p}.a has been prodicted which was verified by operating results of eight PV facades. (orig.) [Deutsch] Photovoltaik (PV) Fassaden ermoeglichen neben der Stromerzeugung zusaetzliche Funktionen wie Wetterschutz bzw. Waermedaemmung des Gebaeudes oder Tageslichtnutzung bzw. Sonnenschutz der Innenraeume. Allerdings muessen fassadenspezifische Betriebsbedingungen, bei der Komponentenauswahl und Systemauslegung beruecksichtigt werden. Unterschiedliche Hinterlueftungsbedingungen fuehren zu einer grossen Bandbreite der maximalen Modultemperatur. PV-Suedfassaden empfangen etwa 30% weniger Jahreseinstrahlung als ein optimal geneigter PV-Generator. Die Haelfte der jaehrlichen Einstrahlung trifft mit Einfallswinkeln groesser 50 auf die vertikal angeordneten Module wodurch die Reflexionsverluste um ca. 4% hoeher sind. Das Maximum der Jahreseinstrahlung liegt nur um 400-600 W/m{sup 2} und erreicht selten Werte ueber 800 W/m{sup 2}. Umliegende Gebaeude oder Vegetation koennen zu Teilabschattungen des Generators fuehren. Fuer eine vertikale PV-Suedfassade wird ein Jahresenergieertrag in Hoehe von 470-560 kWh/kW{sub p}.a prognostiziert, der anhand der Betriebsergebnisse von acht PV-Fassadenanlagen verifiziert werden konnte

  7. Pathogenesis of achalasia cardia

    Institute of Scientific and Technical Information of China (English)

    Uday C Ghoshal; Sunil B Daschakraborty; Renu Singh

    2012-01-01

    Achalasia cardia is one of the common causes of motor dysphagia.Though the disease was first described more than 300 years ago,exact pathogenesis of this condition still remains enigmatic.Pathophysiologically,achalasia cardia is caused by loss of inhibitory ganglion in the myenteric plexus of the esophagus.In the initial stage,degeneration of inhibitory nerves in the esophagus results in unopposed action of excitatory neurotransmitters such as acetylcholine,resulting in high amplitude non-peristaltic contractions (vigorous achalasia); progressive loss of cholinergic neurons over time results in dilation and low amplitude simultaneous contractions in the esophageal body (classic achaiasia).Since the initial description,several studies have attempted to explore initiating agents that may cause the disease,such as viral infection,other environmental factors,autoimmunity,and genetic factors.Though Chagas disease,which mimics achalasia,is caused by an infective agent,available evidence suggests that infection may not be an independent cause of primary achalasia.A genetic basis for achalasia is supported by reports showing occurrence of disease in monozygotic twins,siblings and other first-degree relatives and occurrence in association with other genetic diseases such as Down's syndrome and Parkinson's disease.Polymorphisms in genes encoding for nitric oxide synthase,receptors for vasoactive intestinal peptide,interleukin 23 and the ALADIN gene have been reported.However,studies on larger numbers of patients and controls from different ethnic groups are needed before definite conclusions can be obtained.Currently,the disease is believed to be multi-factorial,with autoimmune mechanisms triggered by infection in a genetically predisposed individual leading to degeneration of inhibitory ganglia in the wall of the esophagus.

  8. Polymerase chain reaction-restriction fragment length polymorphism method to distinguish three mealybug groups within the Planococcus citri-P. minor species complex (Hemiptera: Coccoidea: Pseudococcidae).

    Science.gov (United States)

    Rung, A; Miller, D R; Scheffer, S J

    2009-02-01

    The mealybug species Planococcus citri (Risso) and Planococcus minor (Maskell) (Hemiptera: Coccoidea: Pseudococcidae) have special significance to U.S. quarantine and U.S. agriculture. Commonly intercepted at U.S. ports-of-entry, they are difficult to identify based on morphological characters. This study presents a molecular method for distinguishing P. citri, P. minor, and a genetically distinct group that is morphologically identical to P. citri, from Hawaii. This method uses polymerase chain reaction (PCR) followed by restriction fragment polymorphism analysis (RFLP) using the restriction enzymes BspH1, BsmH1, and HpH1. The resulting band patterns can be visualized in a 2% agarose gel and are sufficient to differentiate between the three entities mentioned above. PCR-RFLP diagnostics can be used for all life stages and is cheaper and faster than DNA sequencing.

  9. Oxynitride Thin Film Barriers for PV Packaging

    Energy Technology Data Exchange (ETDEWEB)

    Glick, S. H.; delCueto, J. A.; Terwilliger, K. M.; Jorgensen, G. J.; Pankow, J. W.; Keyes, B. M.; Gedvilas, L. M.; Pern, F. J.

    2005-11-01

    Dielectric thin-film barrier and adhesion-promoting layers consisting of silicon oxynitride materials (SiOxNy, with various stoichiometry) were investigated. For process development, films were applied to glass (TCO, conductive SnO2:F; or soda-lime), polymer (PET, polyethylene terephthalate), aluminized soda-lime glass, or PV cell (a-Si, CIGS) substrates. Design strategy employed de-minimus hazard criteria to facilitate industrial adoption and reduce implementation costs for PV manufacturers or suppliers. A restricted process window was explored using dilute compressed gases (3% silane, 14% nitrous oxide, 23% oxygen) in nitrogen (or former mixtures, and 11.45% oxygen mix in helium and/or 99.999% helium dilution) with a worst-case flammable and non-corrosive hazard classification. Method employed low radio frequency (RF) power, less than or equal to 3 milliwatts per cm2, and low substrate temperatures, less than or equal to 100 deg C, over deposition areas less than or equal to 1000 cm2. Select material properties for barrier film thickness (profilometer), composition (XPS/FTIR), optical (refractive index, %T and %R), mechanical peel strength and WVTR barrier performance are presented.

  10. Osteoblast role in osteoarthritis pathogenesis.

    Science.gov (United States)

    Maruotti, Nicola; Corrado, Addolorata; Cantatore, Francesco P

    2017-11-01

    Even if osteoarthritis pathogenesis is still poorly understood, numerous evidences suggest that osteoblasts dysregulation plays a key role in osteoarthritis pathogenesis. An abnormal expression of OPG and RANKL has been described in osteoarthritis osteoblasts, which is responsible for abnormal bone remodeling and decreased mineralization. Alterations in genes expression are involved in dysregulation of osteoblast function, bone remodeling, and mineralization, leading to osteoarthritis development. Moreover, osteoblasts produce numerous transcription factors, growth factors, and other proteic molecules which are involved in osteoarthritis pathogenesis. © 2017 The Authors. Journal of Cellular Physiology Published by Wiley Periodicals, Inc.

  11. Patogenicidade de Beauveria bassiana ao psilídeo Diaphorina citri e compatibilidade do fungo com produtos fitossanitários Beauveria bassiana pathogenicity to Diaphorina citri and compatibility of the fungus with phytosanitary products

    Directory of Open Access Journals (Sweden)

    Ana Paula Ferreira Pinto

    2012-12-01

    Full Text Available O objetivo deste trabalho foi avaliar a patogenicidade de Beauveria bassiana a ninfas de Diaphorina citri (Hemiptera: Psyllidae e verificar a compatibilidade do fungo com produtos fitossanitários e sua persistência em plantas de citros. Ninfas de D. citri foram pulverizadas com B. bassiana, nas concentrações 5x10(6, 1x10(7, 5x10(7, 1x10(8, 5x10(8 e 1x10(9 conídios mL-1, para determinação da concentração letal. Para avaliação da compatibilidade do fungo com produtos fitossanitários, extrato de nim e cinco inseticidas de quatro grupos químicos diferentes foram incorporados individualmente ao meio de cultura BDA em que o fungo foi cultivado. Avaliaram-se o crescimento vegetativo, a esporulação e a viabilidade do entomopatógeno. Plantas de citros, mantidas em casa de vegetação, foram tratadas primeiramente com os produtos fitossanitários e depois com o entomopatógeno. Avaliaram-se os tempos de exposição de 24 horas e de 7 e 14 dias. O fungo foi patogênico às ninfas de D. citri; a CL50 foi de 0,4x10(7 e a CL90 de 6,7x10(7 conidios mL-1, no décimo dia de avaliação. Em laboratório, os produtos fitosssanitários reduzem o crescimento do fungo. Em casa de vegetação, os produtos não afetam a sobrevivência do fungo nas plantas de citros.The objective of this work was to evaluate the pathogenicity of Beauveria bassiana to Diaphorina citri (Hemiptera: Psyllidae nymphs, and to check the compatibility of the fungus with phytosanitary products, and its persistence in citrus plants. Nymphs of D. citri were sprayed with B. bassiana in the concentrations 5x10(6, 1x10(7, 5x10(7, 1x10(8, 5x10(8 and 1x10(9 conidia mL-1 for lethal concentration determination. In order to evaluate the compatibility of the phytosanitary products with the fungus, neem extract and five insecticides of four different chemical groups were individually added to PDA culture medium, in which the fungus was cultivated. Vegetative growth, sporulation and viability

  12. The effect of Leptomastix dactylopii parasitism and venom injection on host Planococcus citri

    Directory of Open Access Journals (Sweden)

    D Battaglia

    2014-10-01

    Full Text Available One of the major alterations observed in mealybug Planococcus citri parasitized by Leptomastix dactylopii is a strong reduction of laid eggs, which is evident soon after parasitization. Venom injection in unparasitized hosts determines a drastic reduction of fecundity indicating that this female secretion injected at the oviposition plays a key-role in host regulation. In order to assess the impact of parasitism and venom injection on host reproductive tissues, ovaries were dissected at different time intervals after these treatments and observed by light and transmission electron microscopy. The developing eggs showed clear symptoms of degeneration, already half an hour after parasitization or venom injection. Heat and protease treatments of venom nearly suppressed its effects on host reproduction, indicating that proteins are likely responsible for the observed alterations. The electrophoretic profile of venom proteins covers a wide range of molecular masses between 15 to 200 kDa but five major bands having a molecular mass of about 27, 30, 40, 90 and 120 kDa respectively were more evident. Moreover, to establish any parasitoid preference in host selection, among the adult female mealybugs at different stages of maturation and a possible relation with fecundity reduction in the host, the parasitoid behavior was observed.

  13. Botanicals, selective insecticides, and predators to control Diaphorina citri (Hemiptera: Liviidae) in citrus orchards.

    Science.gov (United States)

    Khan, Azhar A; Afzal, Muhammad; Qureshi, Jawwad A; Khan, Arif M; Raza, Abubakar M

    2014-12-01

    The Asian citrus psyllid (ACP) Diaphorina citri Kuwayama vectors pathogens that cause huanglongbing (HLB) or citrus greening devastating and economically important disease present in most citrus growing regions. Young citrus shoots are required for psyllid reproduction and development. During winter citrus trees produce little or no new growth. Overwintering adults reproduce in spring on newly emerging shoots also attractive to other pests and beneficial insects. Botanicals and relatively selective insecticides could help to conserve beneficial insects and reduce pest resistance to insecticides. Sprays of Azadirachtin (Neem), Tropane (Datura), Spirotetramat, Spinetoram, and broad-spectrum Imidacloprid were evaluated to control ACP in spring and summer on 10-year-old "Kinow" Citrus reticulata Blanco trees producing new growth. Psyllid populations were high averaging 5-9 nymphs or adults per sample before treatment application. Nymphs or adults were significantly reduced to 0.5-1.5 per sample in all treatments for 3 weeks, average 61%-83% reduction. No significant reduction in ladybeetles Adalia bipunctata, Aneglei scardoni, Cheilomenes sexmaculata, and Coccinella septempunctata was observed. Syrphids, spiders and green lacewings were reduced in treated trees except with Tropane. Studies are warranted to assess impact of these predators on ACP and interaction with insecticides. Observed reduction in ACP populations may not be enough considering its reproductive potential and role in the spread of HLB. Follow-up sprays may be required to achieve additional suppression using rotations of different insecticides. © 2014 Institute of Zoology, Chinese Academy of Sciences.

  14. The GC/MS Analysis of Volatile Components Extracted by Different Methods from Exocarpium Citri Grandis

    Directory of Open Access Journals (Sweden)

    Zhisheng Xie

    2013-01-01

    Full Text Available Volatile components from Exocarpium Citri Grandis (ECG were, respectively, extracted by three methods, that is, steam distillation (SD, headspace solid-phase microextraction (HS-SPME, and solvent extraction (SE. A total of 81 compounds were identified by gas chromatography-mass spectrometry including 77 (SD, 56 (HS-SPME, and 48 (SE compounds, respectively. Despite of the extraction method, terpenes (39.98~57.81% were the main volatile components of ECG, mainly germacrene-D, limonene, 2,6,8,10,14-hexadecapentaene, 2,6,11,15-tetramethyl-, (E,E,E-, and trans-caryophyllene. Comparison was made among the three methods in terms of extraction profile and property. SD relatively gave an entire profile of volatile in ECG by long-time extraction; SE enabled the analysis of low volatility and high molecular weight compounds but lost some volatiles components; HS-SPME generated satisfactory extraction efficiency and gave similar results to those of SD at analytical level when consuming less sample amount, shorter extraction time, and simpler procedure. Although SD and SE were treated as traditionally preparative extractive techniques for volatiles in both small batches and large scale, HS-SPME coupled with GC/MS could be useful and appropriative for the rapid extraction and qualitative analysis of volatile components from medicinal plants at analytical level.

  15. Identification of anti-asthmatic compounds in Pericarpium citri reticulatae and evaluation of their synergistic effects

    Institute of Scientific and Technical Information of China (English)

    Qian SHI; Ze LIU; Yang YANG; Peng GENG; Yuan-yuan ZHU; Qi ZHANG; Fang BAI; Gang BAI

    2009-01-01

    Aim: To investigate the anti-asthmatic mechanisms of the traditional Chinese medicine Pericarpium citri reticulatae (PCR).Methods: The alkaloid section (AS) of PCR was extracted using an ion exchange resin, separated, and purified into different fractions by semi-preparative HPLC. These fractions were screened for beta2-adrenergic receptor (β2AR) agonistic activity using rat β2AR-transfected CHO-CRE-EGFP cells. AS and its isolated components were characterized by ultra-performance liquid chromatography/quadrupole time-of-flight MS (UPLC/Q-Tof MS) and were evaluated for their spasmolytic and antitussive activities both in vitro and in vivo in a guinea pig model.Results: We demonstrated that the AS component responsible for activating β2AR signaling was synephrine. Both AS and synephrine showed significant spasmolytic effects on acetylcholine chloride (ACh)-induced contractions in isolated guinea pig trachea, and they protected against histamine-induced experimental asthma by prolonging the latent period. We further identified stachydrine as the antitussive component that could significantly reduce citric acid-induced coughing. The combination of these two bioactive compounds had a more potent spasmolytic activity in comparison with the single use of synephrine or stachydrine.Conclusion: We conclude that synephrine and stachydrine are the key components of AS that mediate asthma relief due to their synergism when used in combination.

  16. Species clarification of Isaria isolates used as biocontrol agents against Diaphorina citri (Hemiptera: Liviidae) in Mexico.

    Science.gov (United States)

    Gallou, Adrien; Serna-Domínguez, María G; Berlanga-Padilla, Angélica M; Ayala-Zermeño, Miguel A; Mellín-Rosas, Marco A; Montesinos-Matías, Roberto; Arredondo-Bernal, Hugo C

    2016-03-01

    Entomopathogenic fungi belonging to the genus Isaria (Hypocreales: Cordycipitaceae) are promising candidates for microbial control of insect pests. Currently, the Mexican government is developing a biological control program based on extensive application of Isaria isolates against Diaphorina citri (Hemiptera: Liviidae), a vector of citrus huanglongbing disease. Previous research identified three promising Isaria isolates (CHE-CNRCB 303, 305, and 307; tentatively identified as Isaria fumosorosea) from Mexico. The goal of this work was to obtain a complete morphological and molecular characterization of these isolates. Comparative analysis of morphology established that the isolates showed similar characteristics to Isaria javanica. Multi-gene analysis confirmed the morphological identification by including the three isolates within the I. javanica clade. Additionally, this work demonstrated the misidentifications of three other Isaria isolates (CHE-CNRCB 310 and 324: I. javanica, formerly I. fumosorosea; CHE-CNRCB 393: I. fumosorosea, formerly Isaria farinosa), underlying the need for a full and correct characterization of an isolate before developing a biological control program. Finally, the inter-simple sequence repeat (ISSR) genotyping method revealed that the CHE-CNRCB 303, 305, and 307 isolates belong to three different genotypes. This result indicates that ISSR markers could be used as a tool to monitor their presence in field conditions.

  17. Odorants for surveillance and control of the Asian Citrus Psyllid (Diaphorina citri.

    Directory of Open Access Journals (Sweden)

    Iliano V Coutinho-Abreu

    Full Text Available BACKGROUND: The Asian Citrus Psyllid (ACP, Diaphorina citri, can transmit the bacterium Candidatus Liberibacter while feeding on citrus flush shoots. This bacterium causes Huanglongbing (HLB, a major disease of citrus cultivation worldwide necessitating the development of new tools for ACP surveillance and control. The olfactory system of ACP is sensitive to variety of odorants released by citrus plants and offers an opportunity to develop new attractants and repellents. RESULTS: In this study, we performed single-unit electrophysiology to identify odorants that are strong activators, inhibitors, and prolonged activators of ACP odorant receptor neurons (ORNs. We identified a suite of odorants that activated the ORNs with high specificity and sensitivity, which may be useful in eliciting behavior such as attraction. In separate experiments, we also identified odorants that evoked prolonged ORN responses and antagonistic odorants able to suppress neuronal responses to activators, both of which can be useful in lowering attraction to hosts. In field trials, we tested the electrophysiologically identified activating odorants and identified a 3-odor blend that enhances trap catches by ∼230%. CONCLUSION: These findings provide a set of odorants that can be used to develop affordable and safe odor-based surveillance and masking strategies for this dangerous pest insect.

  18. Two-Spotted Ladybeetle Adalia bipunctata L. (Coleoptera: Coccinellidae): A Commercially Available Predator to Control Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae)

    Science.gov (United States)

    Afzal, Muhammad; Stansly, Philip A.

    2016-01-01

    The Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) is an economically important pest of citrus because it serves as a vector of the causal pathogens of huanglongbing (HLB) also known as citrus greening disease. The increased use of insecticides for control of D. citri negatively impacts several natural enemies including some effective ladybeetle species which are not available commercially. The two-spotted ladybeetle, Adalia bipunctata (Coleoptera: Coccinellidae) is found in some crop and forest ecosystems of Asia, Europe and North America and available commercially. It is known to attack aphids and mealybugs but there are no published records of feeding on psyllids. We evaluated suitability and preference of A. bipunctata for nymphs of D. citri compared to corn leaf aphid Rhopalosiphum maidis (Hemiptera: Aphididae) a global pest of cereal crops and prey for many predaceous insects. We also compared development and reproduction of A. bipunctata on these two species with frozen eggs of the Mediterranean flour moth Ephestia kuehniella (Lepidoptera: Pyralidae) at 25°C. Initially, more D. citri than R. maidis nymphs were consumed in the no-choice tests although final consumption by larva and adult of A. bipunctata did not differ in the choice and no-choice tests. Larval development was prolonged by one day on D. citri compared to R. maidis nymphs but did not differ between either of these diets and E. kuehniella. Larval survival to adult averaged 93–100% and was not impacted by diet. Adult life span did not differ between diets although those on D. citri and R. maidis nymphs weighed less and produced fewer but more fertile eggs than on E. kuehniella eggs. Significant reduction of D. citri nymphs averaging 54% was observed in colonies caged with adult A. bipunctata on field planted citrus. R° (net reproductive rate) was least for beetles fed R. maidis, but otherwise there were no significant differences in demographic parameters. Successful

  19. Fluctuación poblacional de Diaphorina citri Kuwayana en limón persa (Citrus latifolia Tanaka) en la sabana de Huimanguillo, Tabasco.

    OpenAIRE

    García Garduza, Diógenes

    2012-01-01

    Diaphorina citri Kuwayama es el vector de la enfermedad Huanglongbing, la cual se encuentra actualmente en 14 de los 23 estados productores de cítricos en México. El estado de Tabasco, donde se cultivan 15, 406 ha de estos frutales, aún no es afectado por la enfermedad, por lo cual es importante tomar medidas para controlar las poblaciones del vector, cuya presencia en dicho estado fue detectada en 2005. El objetivo de este trabajo fue determinar la fluctuación poblacional de D. citri y la r...

  20. Remote Sensing of Low and Mid-Latitude Ionospheric Disturbances During Solar Minimum Using CITRIS and CERTO Measurements of TEC and Radio Scintillation

    Science.gov (United States)

    Siefring, C. L.; Bernhardt, P. A.

    2010-12-01

    Unique data on ionospheric plasma disturbances from the Naval Research Laboratory CITRIS (Scintillation and TEC Receiver in Space) instrument will be presented. CITRIS is a multi-band receiver that recorded TEC (Total Electron Content) and radio scintillations from Low-Earth Orbit (LEO) on STPSat1. The 555+/5 km altitude 35° inclination orbit covers low and mid-latitudes. The measurements require propagation from a transmitter to a receiver through the F-region plasma. CITRIS used both 1) satellite beacons in LEO, such as the NRL CERTO (Coherent Electromagnetic Radio TOmography) three-frequency beacons transmitting at 150/400/1067 MHz and 2) the French global network of ground-based DORIS (Doppler Orbitography and Radiopositioning Integrated by Satellite) beacons transmitting at 401.25 and 2036.25 MHz. CITRIS was operated in a complementary fashion with the C/NOFS satellite during most of its first year of operations; C/NOFS carries CERTO beacon along with in-situ diagnostics. CITRIS and ground receivers can simultaneously measure TEC and scintillations on different paths using CERTO on C/NOFS. When C/NOFS is not in view, CITRIS makes measurements from DORIS beacons and other LEO satellites. Because of the orbits CITRIS will always make measurements at the same longitude within 48 min of C/NOFS. The ability to look at multiple paths is unique and useful for studying the spatial extent and time duration of disturbances. The combination of TEC and scintillation measurements provides information on a range of scale-sizes from >1 km to about 100 m. The joint data set on plasma structures at low-latitudes is a focus of our presentation, with the addition of comparisons to CITRIS data taken at mid-latitude. Several types of irregularities have been studied including Spread-F and the newly discovered dawn-side depletions. The data covers large portions of the Earth (including the Pacific, African and South American sectors) during an unusually quite portion of the most

  1. Two-Spotted Ladybeetle Adalia bipunctata L. (Coleoptera: Coccinellidae): A Commercially Available Predator to Control Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae).

    Science.gov (United States)

    Khan, Azhar A; Qureshi, Jawwad A; Afzal, Muhammad; Stansly, Philip A

    2016-01-01

    The Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae) is an economically important pest of citrus because it serves as a vector of the causal pathogens of huanglongbing (HLB) also known as citrus greening disease. The increased use of insecticides for control of D. citri negatively impacts several natural enemies including some effective ladybeetle species which are not available commercially. The two-spotted ladybeetle, Adalia bipunctata (Coleoptera: Coccinellidae) is found in some crop and forest ecosystems of Asia, Europe and North America and available commercially. It is known to attack aphids and mealybugs but there are no published records of feeding on psyllids. We evaluated suitability and preference of A. bipunctata for nymphs of D. citri compared to corn leaf aphid Rhopalosiphum maidis (Hemiptera: Aphididae) a global pest of cereal crops and prey for many predaceous insects. We also compared development and reproduction of A. bipunctata on these two species with frozen eggs of the Mediterranean flour moth Ephestia kuehniella (Lepidoptera: Pyralidae) at 25°C. Initially, more D. citri than R. maidis nymphs were consumed in the no-choice tests although final consumption by larva and adult of A. bipunctata did not differ in the choice and no-choice tests. Larval development was prolonged by one day on D. citri compared to R. maidis nymphs but did not differ between either of these diets and E. kuehniella. Larval survival to adult averaged 93-100% and was not impacted by diet. Adult life span did not differ between diets although those on D. citri and R. maidis nymphs weighed less and produced fewer but more fertile eggs than on E. kuehniella eggs. Significant reduction of D. citri nymphs averaging 54% was observed in colonies caged with adult A. bipunctata on field planted citrus. R° (net reproductive rate) was least for beetles fed R. maidis, but otherwise there were no significant differences in demographic parameters. Successful

  2. National survey report on PV power applications in Switzerland 2006

    Energy Technology Data Exchange (ETDEWEB)

    Huesser, P. [Nova Energie GmbH, Aarau (Switzerland); Hostettler, T. [Ingenieurbuero Hostettler, Berne (Switzerland)

    2007-07-01

    This annual report was published by the Swiss Federal Office of Energy (SFOE) as part of the International Energy Agency's work on the exchange and dissemination of information on photovoltaic power systems (PVPS). The political situation in Switzerland with regard to the promotion of photovoltaics (PV) and new legislation in the energy area is discussed. The report provides information on installed PV power, costs and prices and the Swiss PV industry. Examples of PV applications are presented and data on the cumulative installed PV power in various application sectors is presented and discussed. Highlights, major projects and various demonstration and field-test programmes are dealt with, as are public budgets for market stimulation. Figures on the development, production and prices of PV cells and modules are presented. Swiss balance-of-system products are reviewed, as are PV-related services and the value of the Swiss PV business. A review of non-technical factors and new initiatives completes the report.

  3. Product integrated PV: the future is design and styling

    NARCIS (Netherlands)

    Eggink, Wouter; Reinders, Angèle

    2016-01-01

    In this paper we explore how PV powered products have been designed in the past. For this purpose we have drawn a historical time line of the design features of PV powered products in the context of main stream design and styling. Our time frame is 1970 till 2016, focusing in first instance on consu

  4. Energy requirements and CO2 mitigation potential of PV systems

    NARCIS (Netherlands)

    Alsema, E.A.

    2006-01-01

    In this paper we investigate the energy requirements of PV modules and systems and calculate the Energy Pay-Back Time for two major PV applications. Based on a review of past energy analysis studies we explain the main sources of differences and establish a "best estimate" for key system components.

  5. PV O&M Cost Model and Cost Reduction

    Energy Technology Data Exchange (ETDEWEB)

    Walker, Andy

    2017-03-15

    This is a presentation on PV O&M cost model and cost reduction for the annual Photovoltaic Reliability Workshop (2017), covering estimating PV O&M costs, polynomial expansion, and implementation of Net Present Value (NPV) and reserve account in cost models.

  6. Applications of ``PV Optics`` for solar cell and module design

    Energy Technology Data Exchange (ETDEWEB)

    Sopori, B.L.; Madjdpour, J.; Chen, W. [National Renewable Energy Lab., Golden, CO (United States)

    1998-09-01

    This paper describes some applications of a new optics software package, PV Optics, developed for the optical design of solar cells and modules. PV Optics is suitable for the analysis and design of both thick and thin solar cells. It also includes a feature for calculation of metallic losses related to contacts and back reflectors.

  7. Development of PV powered consumer products using future scenarios

    NARCIS (Netherlands)

    Reinders, A.H.M.E.; Meulen, van der B.J.R.; Eger, A.O.

    2006-01-01

    Given the high potential of PV technology to reduce the environmental impact of electricity use of consumer products, it would be worthwhile to advance the application of PV systems in mass produced products. To date this field of application has been explored only to a limited extent. For this reas

  8. Analysis of Long-Term Performance of PV Systems

    NARCIS (Netherlands)

    Nordmann, T.; Clavadetscher, L.; van Sark, Wilfried; Green, M.

    2015-01-01

    This report describes the activities, conclusions and continued efforts undertaken in Subtask 1 by the participating countries in IEA-PVPS Task 13. Subtask 1 examines the PV power plant as a system. It collects and studies the data supplied from installed operating PV plants from different countries

  9. Solar PV Energy Conversion System and its Configurations

    OpenAIRE

    Ahteshamul Haque

    2016-01-01

    Solar PV based energy conversion system is now used in commercial and residential buildings. Advancements in Power electronics leads the researchers to enhance the use of solar application in various configurations. These configurations may be used to utilize the energy optimally. The main objective of this paper is to present an overview of the various configurations of solar PV energy conversion system

  10. Role of DetR in defence is critical for virulence of Xanthomonas oryzae pv. oryzae.

    Science.gov (United States)

    Nguyen, Minh-Phuong; Park, Jongchan; Cho, Man-Ho; Lee, Sang-Won

    2016-05-01

    Like other bacteria, Xanthomonas oryzae pv. oryzae (Xoo), the causal agent of bacterial leaf blight disease in rice, possesses intracellular signalling systems, known as two-component regulatory systems (TCSs), which regulate pathogenesis and biological processes. Completion of the genome sequences of three Xoo strains has facilitated the functional study of genes, including those of TCSs, but the biological functions of most Xoo TCSs have not yet been uncovered. To identify TCSs involved in Xoo pathogenesis, we generated knockout strains lacking response regulators (RRs, a cytoplasmic signalling component of the TCS) and examined the virulence of the RR knockout strains. This study presents a knockout strain (detR(-) ) lacking the PXO_04659 gene which shows dramatically reduced virulence relative to the wild-type. Our studies to elucidate detR function in Xoo pathogenesis revealed a reduction in extracellular polysaccharide (EPS), intolerance to reactive oxygen species (ROS) and deregulation of iron homeostasis in the detR(-) strain. Moreover, gene expression of regulatory factors, including other RRs and transcription factors (TFs), was altered in the absence of DetR protein, as determined by reverse transcription-polymerase chain reaction (RT-PCR) and/or real-time quantitative RT-PCR analyses. All evidence leads to the conclusion that DetR is essential for Xoo virulence through the regulation of the Xoo defence system including EPS synthesis, ROS detoxification and iron homeostasis, solely or cooperatively with other regulatory factors.

  11. Control químico de Diaphorina citri Kuwayama (Hemíptera: Psyllidae) en lima persa Citrus latifolia Tanaka Chemical control of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) in Persian lime Citrus latifolia Tanaka

    OpenAIRE

    Luis Martín Hernández-Fuentes; Mario Alfonso Urias-López; José Isabel López-Arroyo; Rafael Gómez-Jaimes; Néstor Bautista-Martínez

    2012-01-01

    A nivel mundial, la citricultura representa una actividad de gran importancia. México ocupa el cuarto lugar mundial en producción. Debido a la introducción y dispersión del vector D. citri en todas las zonas citrí colas de México y la reciente detección de la enfermedad conocida como huanglongbing causada por la bacteria Candidatus Liberibacter asiaticus, es necesaria la evaluación de métodos de control de este insecto. En el año 2010 en Nayarit, México, se realizaron pruebas de efectividad t...

  12. Highlights in pathogenesis of vitiligo.

    Science.gov (United States)

    Mohammed, Ghada F; Gomaa, Amal Ha; Al-Dhubaibi, Mohammed Saleh

    2015-03-16

    Vitiligo is a common pigmentary disorder. Many studies across decades and all over the world have attempted to illustrate the pathogenesis behind it; however, the pathogenesis of vitiligo remains elusive. This review article, we present the findings behind the most and updated theories behind this psychologically debilitating and disfiguring disease. The discussion begun with the role of genetic predisposition followed by neural theory first proposed in the 1950s. We highlight the autoimmune hypothesis, followed by the reactive oxygen species model, zinc-α2-glycoprotein deficiency hypothesis, viral theory, intrinsic theory and biochemical, molecular and cellular alterations accounting for loss of functioning melanocytes in vitiligo. Many theories were elaborated to clarify vitiligo pathogenesis. It is a multifactorial disease involving the interplay of several factors. Future research is needed to clarify the interaction of these factors for better understanding of vitiligo pathogenesis and subsequent successful treatment.

  13. [Pseudomembranous colitis: pathogenesis, prevention, treatment].

    Science.gov (United States)

    Zakharova, N V; Fil', T S

    2013-01-01

    The article reviews a pathogenesis of Pseudomembranous colitis. Questions of prevention and treatment of Clostridium difficile--associated diarrhea are shown by the Evidence-based medicine. There is an accent on the rational prescription of antibiotics.

  14. A global strategy for the European PV industry

    Energy Technology Data Exchange (ETDEWEB)

    Viaud, M.; Despotou, E.; Latour, M. [European Photovoltaic Industry Association (EPIA) secretariat, Brussels (Belgium); Hoffmann, W.; Macias, E.; Cameron, M.; Laborde, E. [European Photovoltaic Industry Association (EPIA), Brussels (Belgium)

    2004-07-01

    The objective was to develop a comprehensive strategy that answers to the need of today European PV industry. Namely: - Develop PV markets in Europe - Develop export markets. - Position the European PV industry within the European political environment and support the effort of national actors in their local objectives. This method lends itself to brainstorming to create actions and synergies, on order to achieve strategy objectives. The whole work is based on working groups clearly defined on the purpose, where all EPIA members are invited to participate. The overall first results are presented during the 19. EU PV Conference in Paris and EPIA will do recommendations on actions to be undertaken in the future. This strategy is co-financed by EPIA members and the 6. Framework Programme for research of the European Commission through the PV Catapult project. (authors)

  15. Optimum Design Of On Grid Pv System Using Tracking System

    Directory of Open Access Journals (Sweden)

    Saeed Mansour

    2015-05-01

    Full Text Available Abstract The fossil fuel is a main issue in the world due to the increase of fossil fuel cost and the depletion of the fossil fuel with continuous increasing demand on electricity. With continuous decrease of PV panels cost it is interesting to consider generation of electricity from PV system. To provide electric energy to a load in a remote area where electric grid utility is not available or connection with grid utility is available there are two approaches of photovoltaic system PV without tracking system Fixed System and PV with tracking systems. The result shows that the energy production by using PV with tracking system generates more energy in comparison with fixed panels system. However the cost per produced KWH is less in case of using fixed panels. This is the backbone in choice between two approaches of photovoltaic system. In this work a system design and cost analysis for two approaches of photovoltaic system are considered.

  16. Costs of Residential Solar PV Plants in Distribution Grid Networks

    DEFF Research Database (Denmark)

    Kjær, Søren Bækhøj; Yang, Guangya; Ipsen, Hans Henrik

    2015-01-01

    In this article we investigate the impact of residential solar PV plants on energy losses in distribution networks and their impact on distribution transformers lifetime. Current guidelines in Denmark states that distribution transformers should not be loaded with more than 67% solar PV power...... to avoid accelerated loss of life. If a solar PV plant causes this limit to be exceeded, the particular owner has to pay for upgrading the transformer. Distribution Network Operators also charge an annual tariff from the solar PV plants to cover the expenses to keep the grid capacity available, the so...... called “Availability Tariff”. According to the Danish Energy Regulatory Authority, the Availability Tariff must cover the exact expenses, with energy savings etc. from the solar PV plants taken into consideration. Our conclusion is that a distribution network, which represents a typical residential...

  17. Overview of Recent Grid Codes for PV Power Integration

    DEFF Research Database (Denmark)

    Craciun, Bogdan-Ionut; Kerekes, Tamas; Sera, Dezso;

    2012-01-01

    and Distribution System Operators (DSOs) had to keep the safety and reliability of the network under strict rules and regulations. The aim of the paper is to realize a survey of recent Grid Codes (GC) and regulations for grid connected PV systems. The focus is on grid interface requirements, power quality concerns...... and Anti-Islanding (AI) issues regarding PV systems connected to low voltage (LV) and medium voltage (MV) levels of the network.......The challenge to bring down the cost of produced photovoltaic (PV) power had a major impact on the PV market and in consequence the grid operators experienced higher and higher PV power penetration. The growing share of this decentralized generation plants started to affect the grid stability...

  18. Fire hazard and other safety concerns of PV systems

    Science.gov (United States)

    Dhere, Neelkanth G.

    2011-09-01

    Photovoltaic modules are usually considered safe and reliable. But in case of grid-connected PV systems that are becoming very popular, the issue of fire safety of PV modules is becoming increasingly important due to the employed high voltages of 600 V to 1000 V. The two main factors i.e. open circuiting of the bypass diode and ground fault that are responsible for the fire in the PV systems have been discussed in detail along with numerous real life examples. Recommendations are provided for preventing the fire hazards such as having at least class C fire rated PV modules, proper bypass and blocking diodes and interestingly, having an ungrounded PV system.

  19. Codes, standards, and PV power systems. A 1996 status report

    Energy Technology Data Exchange (ETDEWEB)

    Wiles, J

    1996-06-01

    As photovoltaic (PV) electrical power systems gain increasing acceptance for both off-grid and utility-interactive applications, the safety, durability, and performance of these systems gains in importance. Local and state jurisdictions in many areas of the country require that all electrical power systems be installed in compliance with the requirements of the National Electrical Code{reg_sign} (NEC{reg_sign}). Utilities and governmental agencies are now requiring that PV installations and components also meet a number of Institute of Electrical and Electronic Engineers (IEEE) standards. PV installers are working more closely with licensed electricians and electrical contractors who are familiar with existing local codes and installation practices. PV manufacturers, utilities, balance of systems manufacturers, and standards representatives have come together to address safety and code related issues for future PV installations. This paper addresses why compliance with the accepted codes and standards is needed and how it is being achieved.

  20. Costs of Residential Solar PV Plants in Distribution Grid Networks

    DEFF Research Database (Denmark)

    Kjær, Søren Bækhøj; Yang, Guangya; Ipsen, Hans Henrik

    2015-01-01

    In this article we investigate the impact of residential solar PV plants on energy losses in distribution networks and their impact on distribution transformers lifetime. Current guidelines in Denmark states that distribution transformers should not be loaded with more than 67% solar PV power...... called “Availability Tariff”. According to the Danish Energy Regulatory Authority, the Availability Tariff must cover the exact expenses, with energy savings etc. from the solar PV plants taken into consideration. Our conclusion is that a distribution network, which represents a typical residential...... to avoid accelerated loss of life. If a solar PV plant causes this limit to be exceeded, the particular owner has to pay for upgrading the transformer. Distribution Network Operators also charge an annual tariff from the solar PV plants to cover the expenses to keep the grid capacity available, the so...

  1. Physical Effects of Distributed PV Generation on California's Distribution System

    CERN Document Server

    Cohen, Michael A

    2015-01-01

    Deployment of high-penetration photovoltaic (PV) power is expected to have a range of effects -- both positive and negative -- on the distribution grid. The magnitude of these effects may vary greatly depending upon feeder topology, climate, PV penetration level, and other factors. In this paper we present a simulation study of eight representative distribution feeders in three California climates at PV penetration levels up to 100\\%, supported by a unique database of distributed PV generation data that enables us to capture the impact of PV variability on feeder voltage and voltage regulating equipment. When comparing the influence of feeder location (i.e. climate) versus feeder type on outcomes, we find that location more strongly influences the incidence of reverse power flow, reductions in peak loading and the presence of voltage excursions. On the other hand, we find that feeder characteristics more strongly influence the magnitude of loss reduction and changes in voltage regulator operations. We find th...

  2. Highlights in pathogenesis of vitiligo

    OpenAIRE

    Ghada F. Mohammed; Gomaa, Amal HA; Al-Dhubaibi, Mohammed Saleh

    2015-01-01

    Vitiligo is a common pigmentary disorder. Many studies across decades and all over the world have attempted to illustrate the pathogenesis behind it; however, the pathogenesis of vitiligo remains elusive. This review article, we present the findings behind the most and updated theories behind this psychologically debilitating and disfiguring disease. The discussion begun with the role of genetic predisposition followed by neural theory first proposed in the 1950s. We highlight the autoimmune ...

  3. Molecular mechanisms of rosacea pathogenesis

    Directory of Open Access Journals (Sweden)

    Davydova A.M.

    2013-09-01

    Full Text Available The article presents possible molecular mechanisms for rosacea pathogenesis from current domestic and foreign clinical observations and laboratory research: regulation and expression defects of antimicrobial peptides, vascular endothelial growth factor, the effect of serine proteases, oxidative stress, reactive oxygen species and ferritin on the occurrence and course of rosacea. New developments in molecular biology and genetics are advanced for researching the interaction of multiple factors involved in rosacea pathogenesis, as well as providing the bases for potentially new therapies.

  4. 60Co-γ Irradiation Affects the Enzymatic Antioxidant System of the Citrus Red Mite Panonychus citri (Acari: Tetranychidae

    Directory of Open Access Journals (Sweden)

    Ke Zhang

    2014-05-01

    Full Text Available Radio-(60Co, which emits γ rays, has been used worldwide in pest control. The aim of the present study was to analyze the effect of effective-low-power 60Co-γ irradiation on the enzymatic antioxidant system of the citrus red mite Panonychus citri. One day old female adults were exposed to 0.4 kGy 60Co-γ irradiation and on the, 6th h, 1st day, 2nd day, and 5th day post treatment, the mites were euthanized for biochemical analysis. The activity of superoxide dismutase (SOD, catalase (CAT, peroxidase (POD, phenoloxidase (PO and acetylocholinesterase (AchE were investigated. POD and CAT activities, as well as SOD were higher in the irradiated mites. We found that exposure to 60Co-γ radiation resulted in increased activities of SOD, CAT, POD and decreased AchE activity. When the recovery time lasted till the 5th day, the activities of POD and PO were significantly lower than the control, whereas the SOD, CAT and AchE activities returned to control levels. Cells possess protein repair pathways to rescue oxidized proteins and restore their functions, but if these repair processes fail, oxidized proteins may become cytotoxic. Our results confirm the hypothesis that low dosages of 60Co-γ irradiation increase the level of oxidative stress in P. citri adults in a short time, causing meanwhile damage and sterility. The results of this study also indicate that stress caused by exposure to irradiation could inhibit the cholinergic system in P. citri.

  5. PV Performance Modeling Methods and Practices: Results from the 4th PV Performance Modeling Collaborative Workshop.

    Energy Technology Data Exchange (ETDEWEB)

    Stein, Joshua [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-03-01

    In 2014, the IEA PVPS Task 13 added the PVPMC as a formal activity to its technical work plan for 2014-2017. The goal of this activity is to expand the reach of the PVPMC to a broader international audience and help to reduce PV performance modeling uncertainties worldwide. One of the main deliverables of this activity is to host one or more PVPMC workshops outside the US to foster more international participation within this collaborative group. This report reviews the results of the first in a series of these joint IEA PVPS Task 13/PVPMC workshops. The 4th PV Performance Modeling Collaborative Workshop was held in Cologne, Germany at the headquarters of TÜV Rheinland on October 22-23, 2015.

  6. Innovations in Wind and Solar PV Financing

    Energy Technology Data Exchange (ETDEWEB)

    Cory, K.; Coughlin, J.; Jenkin, T.; Pater, J.; Swezey, B.

    2008-02-01

    There is growing national interest in renewable energy development based on the economic, environmental, and security benefits that these resources provide. Historically, greater development of our domestic renewable energy resources has faced a number of hurdles, primarily related to cost, regulation, and financing. With the recent sustained increase in the costs and associated volatility of fossil fuels, the economics of renewable energy technologies have become increasingly attractive to investors, both large and small. As a result, new entrants are investing in renewable energy and new business models are emerging. This study surveys some of the current issues related to wind and solar photovoltaic (PV) energy project financing in the electric power industry, and identifies both barriers to and opportunities for increased investment.

  7. Fidelity Susceptibility as Holographic PV criticality

    CERN Document Server

    Momeni, Davood; Myrzakulov, Ratbay

    2016-01-01

    Motivated by the fact that the quantum entanglement entropy is dual to an area in AdS, quantities dual to a volume in the AdS have also been recently proposed. These include the holographic complexity and fidelity susceptibility of a quantum system. Even though both of them are dual to an volume in the bulk, there are some interesting difference between them. In this letter, we will explicitly compare them for an $ AdS _4$ solution, and clarify the main differences between them from thermodynamic point of the view. We will also obtain the correct and appropriate holographic dual of the thermodynamic volume of AdS blackhole, and demonstrate that to explain therodynamic in extended phase PV picture, from the AdS/CFT point of view,fidelity susceptibility is the preferred quantity in comparison to holographic complexity.

  8. Managing PV Power on Mars - MER Rovers

    Science.gov (United States)

    Stella, Paul M.; Chin, Keith; Wood, Eric; Herman, Jennifer; Ewell, Richard

    2009-01-01

    The MER Rovers have recently completed over 5 years of operation! This is a remarkable demonstration of the capabilities of PV power on the Martian surface. The extended mission required the development of an efficient process to predict the power available to the rovers on a day-to-day basis. The performance of the MER solar arrays is quite unlike that of any other Space array and perhaps more akin to Terrestrial PV operation, although even severe by that comparison. The impact of unpredictable factors, such as atmospheric conditions and dust accumulation (and removal) on the panels limits the accurate prediction of array power to short time spans. Based on the above, it is clear that long term power predictions are not sufficiently accurate to allow for detailed long term planning. Instead, the power assessment is essentially a daily activity, effectively resetting the boundary points for the overall predictive power model. A typical analysis begins with the importing of the telemetry from each rover's previous day's power subsystem activities. This includes the array power generated, battery state-of-charge, rover power loads, and rover orientation, all as functions of time. The predicted performance for that day is compared to the actual performance to identify the extent of any differences. The model is then corrected for these changes. Details of JPL's MER power analysis procedure are presented, including the description of steps needed to provide the final prediction for the mission planners. A dust cleaning event of the solar array is also highlighted to illustrate the impact of Martian weather on solar array performance

  9. Valley of Death analysis for polymer PV technology; Valley of Death analyse voor polymere PV technologie

    Energy Technology Data Exchange (ETDEWEB)

    Schoots, K. [ECN Beleidsstudies, Petten (Netherlands)

    2013-12-15

    This report describes the results of a qualitative study of the barriers that actors involved in the development and commercialization of polymer solar cells, may encounter. The purpose of this socio-economic research is to identify these barriers for the (market) development of thin film polymeric PV technology and to develop strategies for them in order to overcome the constraints. The necessary data are collected from interviews with actors who are active in the development and deployment of conventional solar cells. Based on the results from this study, it is conclude that it is important for the Organic PV industry to carry out many market experiments beyond the built environment. The report provides recommendations with regard to the markets in which these experiments are most likely to succeed and which drivers should be taken into account [Dutch] Dit rapport beschrijft de resultaten van een kwalitatief onderzoek naar de barrieres die actoren, betrokken bij de ontwikkeling en marktintroductie van polymere zonnecellen, kunnen tegenkomen. Het doel van dit sociaal-economische onderzoek is deze barrieres voor de (markt)ontwikkeling van dunne film polymere PV technologie te identificeren en strategieen te ontwikkelen om ze voor te zijn of ze te overbruggen. De benodigde gegevens worden verzameld uit interviews met actoren die actief zijn in de ontwikkeling en uitrol van conventionele zonnecellen. Op basis van de resultaten uit dit onderzoek komen we tot de conclusie dat het voor de Organische PV sector belangrijk is veel marktexperimenten aan te gaan buiten de gebouwde omgeving. Het rapport geeft aanbevelingen in welke soort markten deze experimenten de meeste kans van slagen hebben en met welke drivers van marktpartijen rekening moet worden gehouden.

  10. SunShot 2030 for Photovoltaics (PV): Envisioning a Low-cost PV Future

    Energy Technology Data Exchange (ETDEWEB)

    Cole, Wesley J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Frew, Bethany A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Gagnon, Pieter J [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Richards, James [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Sun, Yinong [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Margolis, Robert M [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Woodhouse, Michael A [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-09-12

    In this report we summarize the implications, impacts, and deployment potential of reaching the SunShot 2030 targets for the electricity system in the contiguous United States. We model 25 scenarios of the U.S. power sector using the Regional Energy Deployment Systems (ReEDS) and Distributed Generation (dGen) capacity expansion models. The scenarios cover a wide range of sensitivities to capture future uncertainties relating to fuel prices, retirements, renewable energy capital costs, and load growth. We give special attention to the potential for storage costs to also rapidly decline due to its large synergies with low-cost solar. The ReEDS and dGen models project utility- and distributed-scale power sector evolution, respectively, for the United States. Both models have been designed with special emphasis on capturing the unique traits of renewable energy, including variability and grid integration requirements. Across the suite of scenarios modeled, we find that reaching the SunShot 2030 target has the potential to lead to significant capacity additions of PV in the United States. By 2050, PV penetration levels are projected to reach 28-46 percent of total generation. If storage also sees significant reductions in cost, then the 2050 solar penetration levels could reach 41-64 percent. PV deployment is projected to occur in all of the lower 48 states, though the specific deployment level is scenario dependent. The growth in PV is projected to be dominated by utility-scale systems, but the actual mix between utility and distributed systems could ultimately vary depending on how policies, system costs, and rate structures evolve.

  11. Determination of Alternaria Brown Spot (Alternaria alternata f.sp. citri) Disease on Minneola Tangelo in Çukurova Region

    OpenAIRE

    ERKILIÇ, Ali; CANIHOŞ, Yeter; BİÇİCİ, Mehmet

    1998-01-01

    In this study, the incidence and severity of Alternaria brown spot disease (Alternaria alternata f.sp. citri) in the Çukurova region were determined. Thirty-five Minneola tangelo orchards, with a total area of 2497 da, in 24 different locations were surveyed for this purpose. Leaf infections in all orchards were observed in the spring flushing period. Disease severity was found to be 0-10 % in 10 orchards, 11-20 % in 10 orchards, 21-30 % in 7 orchards, 31-40 % in 5 orchards, 42.5 % in 1 orch...

  12. Sub-synchronous resonance damping using high penetration PV plant

    Science.gov (United States)

    Khayyatzadeh, M.; Kazemzadeh, R.

    2017-02-01

    The growing need to the clean and renewable energy has led to the fast development of transmission voltage-level photovoltaic (PV) plants all over the world. These large scale PV plants are going to be connected to power systems and one of the important subjects that should be investigated is the impact of these plants on the power system stability. Can large scale PV plants help to damp sub-synchronous resonance (SSR) and how? In this paper, this capability of a large scale PV plant is investigated. The IEEE Second Benchmark Model aggregated with a PV plant is utilized as the case study. A Wide Area Measurement System (WAMS) based conventional damping controller is designed and added to the main control loop of PV plant in order to damp the SSR and also investigation of the destructive effect of time delay in remote feedback signal. A new optimization algorithm called teaching-learning-based-optimization (TLBO) algorithm has been used for managing the optimization problems. Fast Furrier Transformer (FFT) analysis and also transient simulations of detailed nonlinear system are considered to investigate the performance of the controller. Robustness of the proposed system has been analyzed by facing the system with disturbances leading to significant changes in generator and power system operating point, fault duration time and PV plant generated power. All the simulations are carried out in MATLAB/SIMULINK environment.

  13. Three junction holographic micro-scale PV system

    Science.gov (United States)

    Wu, Yuechen; Vorndran, Shelby; Ayala Pelaez, Silvana; Kostuk, Raymond K.

    2016-09-01

    In this work a spectrum splitting micro-scale concentrating PV system is evaluated to increase the conversion efficiency of flat panel PV systems. In this approach, the dispersed spectrum splitting concentration systems is scaled down to a small size and structured in an array. The spectrum splitting configuration allows the use of separate single bandgap PV cells that increase spectral overlap with the incident solar spectrum. This results in an overall increase in the spectral conversion efficiency of the resulting system. In addition other benefits of the micro-scale PV system are retained such reduced PV cell material requirements, more versatile interconnect configurations, and lower heat rejection requirements that can lead to a lower cost system. The system proposed in this work consists of two cascaded off-axis holograms in combination with a micro lens array, and three types of PV cells. An aspherical lens design is made to minimize the dispersion so that higher concentration ratios can be achieved for a three-junction system. An analysis methodology is also developed to determine the optical efficiency of the resulting system, the characteristics of the dispersed spectrum, and the overall system conversion efficiency for a combination of three types of PV cells.

  14. Kauai Island Utility Co-op (KIUC) PV integration study.

    Energy Technology Data Exchange (ETDEWEB)

    Ellis, Abraham; Mousseau, Tom (Knoxville, TN)

    2011-08-01

    This report investigates the effects that increased distributed photovoltaic (PV) generation would have on the Kauai Island Utility Co-op (KIUC) system operating requirements. The study focused on determining reserve requirements needed to mitigate the impact of PV variability on system frequency, and the impact on operating costs. Scenarios of 5-MW, 10-MW, and 15-MW nameplate capacity of PV generation plants distributed across the Kauai Island were considered in this study. The analysis required synthesis of the PV solar resource data and modeling of the KIUC system inertia. Based on the results, some findings and conclusions could be drawn, including that the selection of units identified as marginal resources that are used for load following will change; PV penetration will displace energy generated by existing conventional units, thus reducing overall fuel consumption; PV penetration at any deployment level is not likely to reduce system peak load; and increasing PV penetration has little effect on load-following reserves. The study was performed by EnerNex under contract from Sandia National Laboratories with cooperation from KIUC.

  15. Sobre o condicionamento alimentar na cochonilha-branca, Planococcus citri (Risso (Hemiptera: pseudococcidae

    Directory of Open Access Journals (Sweden)

    Lenira Viana Costa Santa-Cecília

    2013-03-01

    Full Text Available Estudos do comportamento alimentar mediante a técnica de "Electrical Penetration Graphs" (EPG das cochonilhas-farinhentas (Pseudococcidae provenientes de um hospedeiro de criação alternativo têm mostrado que esses insetos não atingem ou demoram cerca de 9 horas para alcançar a fase floemática. Por outro lado, aqueles provenientes do hospedeiro-fonte atingem a fase floemática mais rapidamente e apresentam maior frequência de alimentação nos vasos crivados. Esses resultados indicam a presença do fenômeno de condicionamento alimentar, ainda não demonstrado em cochonilhas. Assim, o presente trabalho teve como objetivo determinar a existência desse fenômeno em Planococcus citri (Risso (Hemiptera: Pseudococcidae. Foram realizados testes de livre escolha, monitoramento eletrônico (EPG e estudos de alguns parâmetros biológicos. Em todos os experimentos, o cafeeiro (Coffea arabica L., os citros (Citrus sinensis L. e abóbora (Cucurbita maxima L. foram utilizados como substratos de criação (fonte da cochonilha, sendo os tratamentos constituídos pela combinação entre os hospedeiros-fonte e os hospedeiros receptores (café e citros. O teste de escolha entre cafeeiro e citros nas primeiras 72 horas mostrou que as cochonilhas criadas em cafeeiro apresentaram preferência pelo cafeeiro; aquelas originadas dos citros mostraram uma tendência, embora não significativa, em selecionar os citros em relação ao cafeeiro e aquelas criadas em abóbora não mostraram preferência por nenhum dos hospedeiros. Os estudos do comportamento alimentar mediante o monitoramento eletrônico (EPG mostraram que a fase floemática, considerada como a fase de aceitação do hospedeiro, foi mais frequente em cafeeiro, seja com cochonilhas oriundas deste substrato, seja de citros. Aqueles insetos mantidos em abóbora e transferidos para o cafeeiro ou citros apresentaram excepcionalmente ou não apresentaram nenhuma fase floemática, respectivamente. A

  16. New occupational allergen in citrus farmers: citrus red mite (Panonychus citri).

    Science.gov (United States)

    Kim, Y K; Son, J W; Kim, H Y; Park, H S; Lee, M H; Cho, S H; Min, K U; Kim, Y Y

    1999-02-01

    There have been several reports of occupational allergy to spider mites (Tetranychidae), but no published report has described citrus red mite (CRM, Panonychus citri)-induced occupational asthma confirmed by specific bronchial challenge. The purpose of this study was to evaluate clinical and immunologic characteristics of CRM-induced occupational asthma. We encountered 16 cases of CRM-induced occupational asthma among farmers cultivating citrus fruits. Asthmatic attacks corresponded closely with their work on citrus farms. The mean duration of the latent period was 12.9 (range 7 to 20) years. During their first visit to our clinic, nine patients with FEV1 lower than 70% of predictive value showed reversible airway obstruction after inhalation of bronchodilator, and seven with FEV1 greater than 70% of predictive value showed airway hyperresponsiveness to methacholine. Fifteen of the 16 also complained of recurrent nasal symptoms, which had developed at an earlier time than the asthmatic symptoms. They showed strong positive reactions to CRM extract on skin prick test (A/H ratio > or = 1.0) and had high serum specific IgE antibody against CRM which was detected by ELISA. Skin prick test with common inhalant allergens revealed that 10 had an isolated positive response to CRM with negative results to common inhalant allergens in their environment. The ELISA inhibition tests with CRM demonstrated significant inhibitions by CRM in a dose-dependent manner, while minimal inhibitions were noted by D. pteronyssinus and mugwort allergens. These findings suggest that CRM could induce IgE-mediated bronchoconstriction in exposed workers on citrus farm.

  17. Use of the entomopathogenic fungi Metarhizium anisopliae, Cordyceps bassiana and Isaria fumosorosea to control Diaphorina citri (Hemiptera: Psylidae) in Persian lime under field conditions

    Science.gov (United States)

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), is a destructive insect pest in the citriculture, because it is an efficient vector of the proteobacteria, ‘Candidatus Liberibacter asiaticus’ (Las), ‘Ca. L. Africanus’ (Laf), and ‘Ca. L. Americanus’ (Lam). These bacteria c...

  18. A “walker” tool to place Diaphorina citri (Hemiptera: Liviidae) adults at predetermined sites for bioassays of behavior in citrus (Sapindales: Rutacease) trees

    Science.gov (United States)

    A walker tool was developed to assist placement of D. citri on citrus host trees in behavioral bioassays. The walker performs better than a commonly used paintbrush tool in the proportion of successful placements and in the reduction of jumps away from the citrus leaf, although it takes about two mi...

  19. Characterization of a recombinant Cathepsin B-Like cysteine peptidase from Diaphorina citri Kuwayama (Hemiptera: Liviidae): A putative target control of citrus huanglongbing

    Science.gov (United States)

    Huanglongbing (HLB) is one of the most destructive disease affecting citrus plants. The causal agent is associated with the phloem-limited bacterium Candidatus Liberibacter asiaticus (CLas) spread by the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae). Among the control strategies for H...

  20. Global genetic variation in the Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae) and the endosymbiont Wolbachia: links between Iran and the USA detected.

    Science.gov (United States)

    Lashkari, Mohammadreza; Manzari, Shahab; Sahragard, Ahad; Malagnini, Valeria; Boykin, Laura M; Hosseini, Reza

    2014-07-01

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is one of the most serious pests of citrus in the world, because it transmits the pathogen that causes citrus greening disease. To determine genetic variation among geographic populations of D. citri, microsatellite markers, mitochondrial gene cytochrome oxidase I (mtCOI) and the Wolbachia-Diaphorina, wDi, gene wsp sequence data were used to characterize Iranian and Pakistani populations. Also, a Bayesian phylogenetic technique was utilized to elucidate the relationships among the sequences data in this study and all mtCOI and wsp sequence data available in GenBank and the Wolbachia database. Microsatellite markers revealed significant genetic differentiation among Iranian populations, as well as between Iranian and Pakistani populations (FST  = 0.0428, p Mexico, Florida and Texas (USA) are similar. Wolbachia, wDi, wsp sequences were similar among Iranian populations, but different between Iranian and Pakistani populations. The South West Asia (SWA) group is the most likely source of the introduced Iranian populations of D. citri. This assertion is also supported by the sequence similarity of the Wolbachia, wDi, strains from the Florida, USA and Iranian D. citri. These results should be considered when looking for biological controls in either country. © 2013 Society of Chemical Industry.

  1. Overexpression of a Gene Encoding a Catabolite Repression Element in Alternaria citri Causes Severe Symptoms of Black Rot in Citrus Fruit.

    Science.gov (United States)

    Katoh, H; Ohtani, K; Yamamoto, H; Akimitsu, K

    2007-05-01

    ABSTRACT A gene (AcCreA) encoding a catabolite repression element (CreA) with (two zinc fingers of the Cys(2)His(2) type was isolated from the postharvest fungal pathogen Alternaria citri. The AcCreA overexpression mutant AcOEC2 of A. citri showed normal growth on pectin medium and on segments of peel or the juice sac area from citrus fruit. Production of endopolygalacturonase, an essential virulence factor of this pathogen, was similar in AcOEC2 and the wild type in pectin-containing media. However, addition of glucose to the medium showed that carbon catabolite repression of endopolygalacturonase gene (Acpg1) expression, as well as endopolygalacturonase production, was lost in AcOEC2. The wild-type strain of A. citri causes rot mainly in the central axis of citrus fruit without development of rotting in the juice sac area; however, AcOEC2 caused severe black rot symptoms in both the central axis and juice sac areas. These results indicate that AcCreA-mediated catabolite repression controls the virulence or infection of this pathogen, and that the wild-type A. citri does not cause symptoms in the juice sac area due to carbon catabolite repression by sugars in the juice of the juice sac area.

  2. Titers of 'Ca. Liberibacter asiaticus' in Murraya paniculata and Murraya-reared Diaphorina citri are much lower than in citrus and citrus-reared psyllids

    Science.gov (United States)

    Huanglongbing, one of the most devastating diseases of citrus, is associated with the bacterium Candidatus Liberibacter asiaticus vectored by the Asian citrus psyllid, Diaphorina citri, in North America. Murraya paniculata is a common ornamental plant that is an alternate host of Ca. L. asiaticus an...

  3. Natural parasitism of Diaphorina citri Kuwayama (Hemiptera, Psyllidae nymphs by Tamarixia radiata Waterston (Hymenoptera, Eulophidae in São Paulo orange groves

    Directory of Open Access Journals (Sweden)

    Paulo Eduardo Branco Paiva

    2012-12-01

    Full Text Available The psyllid Diaphorina citri Kuwayama 1908 has become the main citrus pest species in the state of São Paulo, Brazil, after the introduction of the huanglongbing or citrus greening. This study evaluated the parasitism of 3rd, 4th and 5th instar D. citri nymphs by Tamarixia radiata (Waterston, 1922 in citrus groves under a regimen of regular insecticide applications in ten producing regions: Araraquara, Barretos, Bauru, Botucatu, Franca, Itapetininga, Jaú, Limeira, Lins and São João da Boa Vista. Sixty-nine samples of new branches infested with nymphs of D. citri were collected from 2005 to 2008 in orange groves ranging from 1 to 20 years old, of the varieties Hamlin, Pera, Valencia and Natal. The parasitoid T. radiata is widely distributed in São Paulo orange groves, and was identified in 50 (72% of the samples, showing a mean parasitism rate of 12.4%. The highest parasitism rate was observed in the "summer" (from January through March, with a mean of 25.7%. Nymphal parasitism was above 90% in two samples. The probable causes of the variations in parasitism of D. citri by T. radiata are discussed.

  4. Cloning and expressing a highly functional and substrate specific farnesoic acid o-methyltransferase from the Asian citrus psyllid (Diaphorina citri Kuwayama)

    Science.gov (United States)

    The Asian citrus psyllid, Diaphorina citri, transmits a phloem-limited bacterium, Candidatus Liberibacter asiaticus that causes citrus greening disease. Because juvenile hormone (JH) plays an important role in adult and nymphal development, we studied the final steps in juvenile hormone biosynthesis...

  5. Impedance characterization of PV modules in outdoor conditions

    DEFF Research Database (Denmark)

    Oprea, Matei-lon; Thorsteinsson, Sune; Spataru, Sergiu;

    2016-01-01

    Impedance spectroscopy (IS) has been used for laboratory characterizations of photovoltaic (PV) technologies under well controlled conditions. This work applies IS for outdoor characterization of PV panels, in order to observe the effect of irradiance (G) and temperature (T) on the PV module’s...... impedance spectrum, and further construct an impedance model that can link environmental changes to the model’s parameters. To achieve this, an optimized setup has been developed for long-term impedance spectra monitoring synchronised with accurate irradiance and temperature data. Preliminary results show...

  6. PV Validation and Bankability Workshop: San Jose, California

    Energy Technology Data Exchange (ETDEWEB)

    Granata, J.; Howard, J.

    2011-12-01

    This report is a collaboration between Sandia National Laboratories, the National Renewable Energy Laboratory, and the Florida Solar Energy Center (FSEC). The report provides feedback from the U.S. Department of Energy's (DOE) Solar Program PV Validation and Bankability Workshop in San Jose, California on August 31, 2011. It focuses on the current state of PV in the United States, private funding to fund U.S. PV industry growth, roles and functions of the regional test center program, and ways to improve the current validation and bankability practices.

  7. PV Project Finance in the United States, 2016

    Energy Technology Data Exchange (ETDEWEB)

    Feldman, David; Lowder, Travis; Schwabe, Paul

    2016-09-01

    This brief is a compilation of data points and market insights that reflect the state of the project finance market for solar photovoltaic (PV) assets in the United States as of the third quarter of 2016. This information can generally be used as a simplified benchmark of the costs associated with securing financing for solar PV as well as the cost of the financing itself (i.e., the cost of capital). Three sources of capital are considered -- tax equity, sponsor equity, and debt -- across three segments of the PV marketplace.

  8. Monitoring and Analysis of Two Grid Connected PV Systems

    OpenAIRE

    2013-01-01

    International audience; In this paper, two grid connected photovoltaic systems are studied and monitored for fault detection ad predictive reliability. The first PV grid, is at CNRS-PROMES laboratory in Perpignan, built in 2001 with 3 PV arrays named "Shed","Brise soleil","Mur rideau") connected to the grid thanks to many inverter of different power (3 of 4KWC and 2 of 2.5KWC). The second one is at CNRS-LAAS in Toulouse with a power of 100kWc. It is composed of a facade of 36kWc PV array and ...

  9. CPV Vs. PV from a grid-matching perspective

    Science.gov (United States)

    Strobach, E.; Bader, S.; Faiman, D.; Solomon, A. A.; Meron, G.

    2012-10-01

    In a recently-published series of papers we studied the general problem of matching large PV systems of various kinds to the electricity grid. In those studies CPV systems were simulated via an artificial ansatz in which they were treated as 2-axis flat-panel PV systems whose light sensitivity is only to the direct normal component (DNI) of solar irradiance. The present study replaces this ansatz with an experimentally validated model of a real CPV system. We compare a genuine 2-axis high-concentration CPV system with a static flat-panel PV system from the standpoint of matching both system types to the Israeli electricity grid.

  10. Power Electronic System for Multi-MW PV sites

    DEFF Research Database (Denmark)

    Paasch, Kasper

    The work presented in this thesis addresses the optimization potential of large PV power plants with respect to energy production during periods of moving clouds. Presently the number and size of utility scale Photo Voltaic (PV) power plants in the megawatt range is increasing and the market...... of energy is in the range ... for field use, is battery operated and has been applied for the characterization of a solar panel over a period of 6 months at the ESTER Outdoor PV monitoring station in Rome, Italy....

  11. Design of a Solar Tracker System for PV Power Plants

    Directory of Open Access Journals (Sweden)

    Tiberiu Tudorache

    2010-04-01

    Full Text Available This paper deals with the design and execution of a solar tracker systemdedicated to the PV conversion panels. The proposed single axis solar tracker deviceensures the optimization of the conversion of solar energy into electricity by properlyorienting the PV panel in accordance with the real position of the sun. The operation of theexperimental model of the device is based on a DC motor intelligently controlled by adedicated drive unit that moves a mini PV panel according to the signals received from twosimple but efficient light sensors. The performance and characteristics of the solar trackerare experimentally analyzed.

  12. Measures for diffusion of solar PV in selected African countries

    DEFF Research Database (Denmark)

    Nygaard, Ivan; Hansen, Ulrich Elmer; Mackenzie, Gordon A.;

    2015-01-01

    This paper investigates how African governments are considering supporting and promoting the diffusion of solar PV. This issue is explored by examining so-called ‘technology action plans (TAPs)’, which were main outputs of the Technology Needs Assessment project implemented in 10 African countries...... that governments’ strategies to promoting solar PV are moving from isolated projects towards frameworks for market development and that there are high expectations to upgrading in the PV value chain through local assembly of panels and local production of other system elements. Commonly identified measures include...... support to: local production; financing schemes; tax exemptions; establishment and reinforcement of standards; technical training; and research and development....

  13. Detection of 'Candidatus Liberibacter asiaticus' in Diaphorina citri and its importance in the management of citrus huanglongbing in Florida.

    Science.gov (United States)

    Manjunath, K L; Halbert, S E; Ramadugu, C; Webb, S; Lee, R F

    2008-04-01

    Citrus huanglongbing (HLB or citrus greening), is a highly destructive disease that has been spreading in both Florida and Brazil. Its psyllid vector, Diaphorina citri Kuwayama, has spread to Texas and Mexico, thus threatening the future of citrus production elsewhere in mainland North America. Even though sensitive diagnostic methods have been developed for detection of the causal organisms, Candidatus Liberibacter spp., the pathogen cannot be detected consistently in plants until symptoms develop, presumably because of low titer and uneven distribution of the causal bacteria in nonsymptomatic tissues. In the present study, TaqMan based real-time quantitative polymerase chain reaction methodology was developed for detection of 'Ca. L. asiaticus' in D. citri. Over 1,200 samples of psyllid adults and nymphs, collected from various locations in Florida, from visually healthy and HLB symptomatic trees at different times of the year were analyzed to monitor the incidence and spread of HLB. The results showed that spread of 'Ca. L. asiaticus' in an area may be detected one to several years before the development of HLB symptoms in plants. The study suggests that discount garden centers and retail nurseries may have played a significant role in the widespread distribution of psyllids and plants carrying HLB pathogens in Florida.

  14. Functional analysis of a chitinase gene during the larval-nymph transition in Panonychus citri by RNA interference.

    Science.gov (United States)

    Xia, Wen-Kai; Shen, Xiao-Min; Ding, Tian-Bo; Niu, Jin-Zhi; Zhong, Rui; Liao, Chong-Yu; Feng, Ying-Cai; Dou, Wei; Wang, Jin-Jun

    2016-09-01

    Chitinases are hydrolytic enzymes that are required for chitin degradation and reconstruction in arthropods. In this study, we report a cDNA sequence encoding a putative chitinase (PcCht1) from the citrus red mite, Panonychus citri. The PcCht1 (564 aa) possessed a signal peptide, a conserver domain, and a chitin-binding domain. Structural and phylogenetic analyses found that PcCht1 had high sequence similarity to chitinases in Tetranychus urticae. Real-time quantitative PCR analyses showed that the transcript levels of PcCht1 peaked periodically in larval and nymph stages. Moreover, significant increase of PcCht1 transcript level in the larvae was observed upon the exposure of diflubenzuron. In contrast, exposures of the larvae to diflubenzuron resulted in the decreased chitin content. Furthermore, through a feeding-based RNA interference approach, we were able to reduce the PcCht1 transcript level by 59.7 % in the larvae, and consequently the treated larvae showed a very low molting rate compared with the control. Our results expanded the understanding of the important role of PcCht1 in the growth and development of P. citri.

  15. Huntington disease: pathogenesis and treatment.

    Science.gov (United States)

    Dayalu, Praveen; Albin, Roger L

    2015-02-01

    Huntington disease (HD) is an autosomal dominant inherited neurodegenerative disease characterized by progressive motor, behavioral, and cognitive decline, culminating in death. It is caused by an expanded CAG repeat in the huntingtin gene. Even years before symptoms become overt, mutation carriers show subtle but progressive striatal and cerebral white matter atrophy by volumetric MRI. Although there is currently no direct treatment of HD, management options are available for several symptoms. A better understanding of HD pathogenesis, and more sophisticated clinical trials using newer biomarkers, may lead to meaningful treatments. This article reviews the current knowledge of HD pathogenesis and treatment.

  16. [Asteatotic dermatitis: etiology and pathogenesis].

    Science.gov (United States)

    Zhou, Li-juan; Lyu, Zhong-fa

    2015-07-01

    Asteatotic dermatitis (AsD) is a common skin disease characterized by dry skin, itching, erythema, peeling and other skin lesions. It results from the damage in cutaneous barrier related to age, seasonal climate and bathing habits, and presents dysfunction of sebaceous, sweat glands and the increase of transepidermal water loss. The pathogenesis of AsD is not clear. Previous studies mainly focused on the relationship between skin barrier damage and bathing habits, age or gender. Recently, more studies focus on its relationship with other systematic diseases and drugs. This paper reviews etiology and pathogenesis of AsD to provide new ideas for the diagnosis and treatment of AsD.

  17. Characterization of a Recombinant Cathepsin B-Like Cysteine Peptidase from Diaphorina citri Kuwayama (Hemiptera: Liviidae): A Putative Target for Control of Citrus Huanglongbing.

    Science.gov (United States)

    Ferrara, Taíse Fernanda da Silva; Schneider, Vanessa Karine; Kishi, Luciano Takeshi; Carmona, Adriana Karaoglanovic; Alves, Marcio Fernando Madureira; Belasque-Júnior, Jose; Rosa, José César; Hunter, Wayne Brian; Henrique-Silva, Flávio; Soares-Costa, Andrea

    2015-01-01

    Huanglonbing (HLB) is one of the most destructive disease affecting citrus plants. The causal agent is associated with the phloem-limited bacterium Candidatus Liberibacter asiaticus (CLas) and the psyllid Diaphorina citri, vector of disease, that transmits the bacterium associated with HLB. The control of disease can be achieved by suppressing either the bacterium or the vector. Among the control strategies for HLB disease, one of the widely used consists in controlling the enzymes of the disease vector, Diaphorina citri. The insect Diaphorina citri belongs to the order Hemiptera, which frequently have cysteine peptidases in the gut. The importance of this class of enzymes led us to search for enzymes in the D. citri transcriptome for the establishment of alternatives strategies for HLB control. In this study, we reported the identification and characterization of a cathepsin B-like cysteine peptidase from D. citri (DCcathB). DCcathB was recombinantly expressed in Pichia pastoris, presenting a molecular mass of approximately 50 kDa. The enzyme hydrolyzed the fluorogenic substrate Z-F-R-AMC (Km = 23.5 μM) and the selective substrate for cathepsin B, Z-R-R-AMC (Km = 6.13 μM). The recombinant enzyme was inhibited by the cysteine protease inhibitors E64 (IC50 = 0.014 μM) and CaneCPI-4 (Ki = 0.05 nM) and by the selective cathepsin B inhibitor CA-074 (IC50 = 0.095 nM). RT-qPCR analysis revealed that the expression of the DCcathB in nymph and adult was approximately 9-fold greater than in egg. Moreover, the expression of this enzyme in the gut was 175-fold and 3333-fold higher than in the remaining tissues and in the head, respectively, suggesting that DCcathB can be a target for HLB control.

  18. Characterization of a Recombinant Cathepsin B-Like Cysteine Peptidase from Diaphorina citri Kuwayama (Hemiptera: Liviidae: A Putative Target for Control of Citrus Huanglongbing.

    Directory of Open Access Journals (Sweden)

    Taíse Fernanda da Silva Ferrara

    Full Text Available Huanglonbing (HLB is one of the most destructive disease affecting citrus plants. The causal agent is associated with the phloem-limited bacterium Candidatus Liberibacter asiaticus (CLas and the psyllid Diaphorina citri, vector of disease, that transmits the bacterium associated with HLB. The control of disease can be achieved by suppressing either the bacterium or the vector. Among the control strategies for HLB disease, one of the widely used consists in controlling the enzymes of the disease vector, Diaphorina citri. The insect Diaphorina citri belongs to the order Hemiptera, which frequently have cysteine peptidases in the gut. The importance of this class of enzymes led us to search for enzymes in the D. citri transcriptome for the establishment of alternatives strategies for HLB control. In this study, we reported the identification and characterization of a cathepsin B-like cysteine peptidase from D. citri (DCcathB. DCcathB was recombinantly expressed in Pichia pastoris, presenting a molecular mass of approximately 50 kDa. The enzyme hydrolyzed the fluorogenic substrate Z-F-R-AMC (Km = 23.5 μM and the selective substrate for cathepsin B, Z-R-R-AMC (Km = 6.13 μM. The recombinant enzyme was inhibited by the cysteine protease inhibitors E64 (IC50 = 0.014 μM and CaneCPI-4 (Ki = 0.05 nM and by the selective cathepsin B inhibitor CA-074 (IC50 = 0.095 nM. RT-qPCR analysis revealed that the expression of the DCcathB in nymph and adult was approximately 9-fold greater than in egg. Moreover, the expression of this enzyme in the gut was 175-fold and 3333-fold higher than in the remaining tissues and in the head, respectively, suggesting that DCcathB can be a target for HLB control.

  19. Risk assessment of various insecticides used for management of Asian citrus psyllid, Diaphorina citri in Florida citrus, against honey bee, Apis mellifera.

    Science.gov (United States)

    Chen, Xue Dong; Gill, Torrence A; Pelz-Stelinski, Kirsten S; Stelinski, Lukasz L

    2017-01-23

    The Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a major pest of citrus trees worldwide. A wide variety of insecticides are used to manage D. citri populations within citrus groves in Florida. However, in areas shared by citrus growers and beekeepers the use of insecticides may increase the risks of Apis mellifera  L. (Hymenoptera: Apidae) loss and contaminated honey. The objective of this research was to determine the environmental toxicity of insecticides, spanning five different modes of action used to control D. citri, to A. mellifera. The insecticides investigated were imidacloprid, fenpropathrin, dimethoate, spinetoram and diflubenzuron. In laboratory experiments, LD50 values were determined and ranged from 0.10 to 0.53 ng/μl for imidacloprid, fenpropathrin, dimethoate and spinetoram. LD50 values for diflubenzuron were >1000 ng/μl. Also, a hazard quotient was determined and ranged from 1130.43 to 10893.27 for imidacloprid, fenpropathrin, dimethoate, and spinetoram. This quotient was mellifera 3 and 7 days after application. Spinetoram and imidacloprid were moderately toxic to A. mellifera at the recommended rates for D. citri. Diflubenzuron was not toxic to A. mellifera in the field as compared with untreated control plots. Phenoloxidase (PO) activity of A. mellifera was higher than in untreated controls when A. mellifera were exposed to 14 days old residues. The results indicate that diflubenzuron may be safe to apply in citrus when A. mellifera are foraging, while most insecticides used for management of D. citri in citrus are likely hazardous under various exposure scenarios.

  20. A comparison of design features of 80 pv-powered products

    NARCIS (Netherlands)

    Apostolou, G.; Reinders, A.H.M.E.

    2012-01-01

    In this paper 80 commercially available PV products have been analysed. The data set comprises 46 low power PV products in the range of 0 to 17 Wp and 34 PV products with a power of 17 Wp up to 27 kWp. The goal of our study is to investigate and evaluate features of PV products that are available on

  1. Robustness analysis of the efficiency in PV inverters

    DEFF Research Database (Denmark)

    Pigazo, Alberto; Liserre, Marco; Blaabjerg, Frede;

    2013-01-01

    During last years an increasing attention has been paid to the efficiency of grid-connected PV inverters. They are manufactured from a number of discrete components and by using a certain topology and control strategy. Hence, the performance of a certain PV inverter not only depends on the selected...... topology and control strategy but also on the characteristics of the employed components. The aim of this paper is evaluate the effect of physical variations associated to the main components on the overall efficiency of PV inverters. It is concluded that a statistical evaluation of the power converter...... provides a better understanding of the PV inverter performance and, in this sense, the definition of the European Efficiency must be reviewed in order to show the quality of the manufactured product....

  2. Heritage plaza parking lots improvement project- Solar PV installation

    Energy Technology Data Exchange (ETDEWEB)

    Hooks, Todd [Agua Caliente Indian Reservation, Palm Springs, CA (United States)

    2017-03-31

    The Agua Caliente Band of Cahuilla Indians (ACBCI or the “Tribe”) installed a 79.95 kW solar photovoltaic (PV) system to offset the energy usage costs of the Tribal Education and Family Services offices located at the Tribe's Heritage Plaza office building, 90I Tahquitz Way, Palm Springs, CA, 92262 (the "Project"). The installation of the Solar PV system was part of the larger Heritage Plaza Parking Lot Improvements Project and mounted on the two southern carport shade structures. The solar PV system will offset 99% of the approximately 115,000 kWh in electricity delivered annually by Southern California Edison (SCE) to the Tribal Education and Family Services offices at Heritage Plaza, reducing their annual energy costs from approximately $22,000 annually to approximately $200. The total cost of the proposed solar PV system is $240,000.

  3. Retaining the Value of PV at High Penetration Workshop

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, Sarah; Bolen, Michael

    2016-10-13

    PV prices have dropped and are now attractive without incentives for peaking applications in some locations. Modeling suggests and, empirically, some regions demonstrate that as PV penetration increases its value decreases, predominantly due to a decrease in energy and capacity value. It is not apparent what technologies and price may be needed for PV to supply tens of percent of electricity in the most economically efficient manner. A 1-day workshop was co-sponsored by EPRI and NREL with support from ASU. A dozen presentations and discussions introduced how the interplay of various technologies impact the value of PV, identified technical challenges and gaps impeding implementation, and discussed future R&D needs and opportunities.

  4. Measures for diffusion of solar PV in selected African countries

    DEFF Research Database (Denmark)

    Nygaard, Ivan; Hansen, Ulrich Elmer; Mackenzie, Gordon A.

    2017-01-01

    that governments’ strategies to promoting solar PV are moving from isolated projects towards frameworks for market development and that there are high expectations to upgrading in the PV value chain through local assembly of panels and local production of other system elements. Commonly identified measures include......This paper investigates how African governments are considering supporting and promoting the diffusion of solar PV. This issue is explored by examining so-called ‘technology action plans (TAPs)’, which were main outputs of the Technology Needs Assessment project implemented in 10 African countries...... from 2010 to 2013. The paper provides a review of three distinct but characteristic trajectories for PV market development in Kenya (private-led market for solar home systems), Morocco (utility-led fee-for service model) and Rwanda (donorled market for institutional systems). The paper finds...

  5. New test and characterization methods for PV modules and cells

    Energy Technology Data Exchange (ETDEWEB)

    Van Aken, B.; Sommeling, P. [ECN Solar Energy, Petten (Netherlands); Scholten, H. [Solland, Heerlen (Netherlands); Muller, J. [Moser-Baer, Eindhoven (Netherlands); Grossiord, N. [Holst Centre, Eindhoven (Netherlands); Smits, C.; Blanco Mantecon, M. [Holland Innovative, Eindhoven (Netherlands); Verheijen, M.; Van Berkum, J. [Philips Innovation Services, Eindhoven (Netherlands)

    2012-08-15

    The results of the project geZONd (shared facility for solar module analysis and reliability testing) are described. The project was set up by Philips, ECN, Holst, Solland, OM and T and Holland Innovative. The partners have shared most of their testing and analysis equipment for PV modules and cells, and together developed new or improved methods (including the necessary application know-how). This enables faster and more efficient innovation projects for each partner, and via commercial exploitation for other interested parties. The project has concentrated on five failure modes: corrosion, delamination, moisture ingress, UV irradiation, and mechanical bending. Test samples represented all main PV technologies: wafer based PV and rigid and flexible thin-film PV. Breakthroughs are in very early detection of corrosion, in quantitative characterization of adhesion, in-situ detection of humidity and oxygen inside modules, and ultra-fast screening of materials on UV stability.

  6. Design Considerations for Stand-Alone Photovoltaic (PV Cell Applications

    Directory of Open Access Journals (Sweden)

    Mehmet Cebeci

    2013-06-01

    Full Text Available Solar energy is one of the most important renewable energy sources. The photovoltaic (PV cell systems are used to convert solar energy into electricity. PV systems are divided into two as fixed systems and tracking systems. Fixed systems are mounted at a certain tilt with horizontal to make full use of sunlight. The tilt angle of PV arrays in a fixed system depends on the location and time. If this tilt angle is determined well, the amount of insolation and the energy that is generated increases. When a stand-alone PV cell system is being chosen, certain design operations should be implemented. The number of modules and batteries needed for any system should be calculated by means of the amount of load, insolation level, module characteristics, etc. The design of system is finalized according to the energy demand.

  7. Control of Single-Stage Single-Phase PV inverter

    DEFF Research Database (Denmark)

    Ciobotaru, Mihai; Teodorescu, Remus; Blaabjerg, Frede

    2005-01-01

    In this paper the issue of control strategies for single-stage photovoltaic (PV) inverter is addressed. Two different current controllers have been implemented and an experimental comparison between them has been made. A complete control structure for the single-phase PV system is also presented....... The main elements of the PV control structure are: - a maximum power point tracker (MPPT) algorithm using the incremental conductance method; - a synchronization method using the phase-locked-loop (PLL), based on delay; - the input power control using the dc voltage controller and power feed......-forward; - and the grid current controller implemented in two different ways, using the classical proportional integral (PI) and the novel proportional resonant (PR) controllers. The control strategy was tested experimentally on 1.5 kW PV inverter....

  8. Angle Resolved Performance Measurements on PV Glass and Modules

    DEFF Research Database (Denmark)

    Juutilainen, Line Tollund; Thorsteinsson, Sune; Poulsen, Peter Behrensdorff

    2016-01-01

    the concept of PV balconies as cost efficient and easy way of integrating PV into buildings. The experimental work consists of the fabrication of single cell mini modules with different glass covering, and characterizing their angular response in a custom made setup, where only the direct sunlight is used......The angular response of PV-modules has significant impact on the energy production. This is especially pronounced in BIPV where installation angles often are far from optimal. Nevertheless, a gain in energy yield may be obtained by choosing a proper glass as superstrate. In this work we present...... as a light source. As a special case we estimate the annual yield for each glass in the case of PV balconies for a specific geographical location and orientation of the module....

  9. PV GRID Advisory Paper. Consultation version: key recommendations

    Energy Technology Data Exchange (ETDEWEB)

    Barth, Bianca; Concas, Giorgia; Cossent, Rafael; Franz, Oliver; Frias, Pablo; Hermes, Roland; Lama, Riccardo; Loew, Holger; Mateo, Carlos; Rekinger, Manoel; Sonvilla, Paolo Michele; Vandenbergh, Michel

    2014-01-15

    PV GRID is a transnational collaborative effort under the umbrella of the Intelligent Energy Europe programme. The main project goal is to enhance photovoltaic (PV) hosting capacity in distribution grids while overcoming regulatory and normative barriers hampering the application of available technical solutions. The European PV GRID advisory paper aims at providing an overview of the issues and barriers that need to be addressed in order to enhance the distribution grid hosting capacity for PV and other distributed generation (DG).To this purpose, barriers are classified as either cross-cutting challenges or specific barriers, depending on whether they have an overarching, system-wide character or rather focus on one single issue such as curtailment, self-consumption or storage. Finally, a set of preliminary recommendations on how to overcome these issues is presented, allowing for the implementation of the identified technical solutions.

  10. Promotional drivers for grid-connected PV

    Energy Technology Data Exchange (ETDEWEB)

    Lopez Polo, A.; Hass, R.; Suna, D.

    2009-03-15

    This report for the International Energy Agency (IEA) made by Task 10 of the Photovoltaic Power Systems (PVPS) programme takes a look at promotional measures for grid-connected photovoltaic systems. The mission of the Photovoltaic Power Systems Programme is to enhance the international collaboration efforts which accelerate the development and deployment of photovoltaic solar energy. The objective of Task 10 is stated as being to enhance the opportunities for wide-scale, solution-oriented application of photovoltaics in the urban environment. The paper discusses the core objective of this study which was to analyse the success of various governmental regulatory programs and governmental and non-governmental marketing programs for grid-connected PV systems. To meet this objective, a review of the most important past and current programs around the world was conducted. The theoretical bases of supply and demand are explained and the types of existing strategies are documented in a second Section. In Chapter 3, various programs around the world are described. Chapter 4 focuses on defining success criteria which will be used for the analysis of the programs. Finally, the major conclusions drawn complete this analysis.

  11. The Ramakrishna Mission economic PV development initiative

    Energy Technology Data Exchange (ETDEWEB)

    Stone, J.L.; Ullal, H.S. [National Renewable Energy Lab., Golden, CO (United States); Sherring, C. [Sherring Energy Associates, Princeton, NJ (United States)

    1998-09-01

    India is the world`s second most populous country, quickly approaching one billion persons. Although it has a well-developed electricity grid, many of the people have little or no access to electricity and all of the benefits associated with it. There are areas that are isolated from the grid and will not be connected for many years, if ever. One such area is the Sundarbans located in the delta region of the two great rivers, the Ganges and Brahmaputra, partially in India and partially in Bangladesh. It is estimated that 1.5 million people live in this area, crisscrossed by many islands and rivers, who have only marginal supplies of electricity generated primarily from diesel generators and batteries. Working with the regional non-governmental organization (NGO), the Ramakrishna Mission, and the West Bengal Renewable Energy Development Agency, the governments of India and the US initiated a rural electrification initiative to demonstrate the economic and technical feasibility of photovoltaics to provide limited supplies of electricity for such applications as solar home lighting systems (SHS), water pumping, vaccine refrigeration, communications, and economic development activities. This paper details initial results from approximately 30 kilowatts of PV systems installed in the area, including socio-economic impacts and technical performance.

  12. Evaluation of PV Module Field Performance

    Energy Technology Data Exchange (ETDEWEB)

    Wohlgemuth, John; Silverman, Timothy; Miller, David C.; McNutt, Peter; Kempe, Michael; Deceglie, Michael

    2015-06-14

    This paper describes an effort to inspect and evaluate PV modules in order to determine what failure or degradation modes are occurring in field installations. This paper will report on the results of six site visits, including the Sacramento Municipal Utility District (SMUD) Hedge Array, Tucson Electric Power (TEP) Springerville, Central Florida Utility, Florida Solar Energy Center (FSEC), the TEP Solar Test Yard, and University of Toledo installations. The effort here makes use of a recently developed field inspection data collection protocol, and the results were input into a corresponding database. The results of this work have also been used to develop a draft of the IEC standard for climate and application specific accelerated stress testing beyond module qualification. TEP Solar Test Yard, and University of Toledo installations. The effort here makes use of a recently developed field inspection data collection protocol, and the results were input into a corresponding database. The results of this work have also been used to develop a draft of the IEC standard for climate and application specific accelerated stress testing beyond module qualification. TEP Solar Test Yard, and University of Toledo installations. The effort here makes use of a recently developed field inspection data collection protocol, and the results were input into a corresponding database. The results of this work have also been used to develop a draft of the IEC standard for climate and application specific accelerated stress testing beyond module qualification.

  13. Performance and Degradation Analysis of Operating PV Systems

    Science.gov (United States)

    Da Silva Freire, Felipe

    The environmental concerns together with the decrease in technology cost lead the solar market to growth rapidly along the last decade. The photovoltaic (PV) systems are one of the solar energy alternatives and the silicon solar cells are currently the most widespread technology. Photovoltaic (PV) modules are considered the most reliable component of a photovoltaic system. The reliability and lifetime depends on the modules energy conversion performance and degradation modes. The analysis of monitoring data give insights about the PV system performance along its service time. The comparison between this data and mathematical models configure a way to predict the futures and new PV installations performance. The goal of this study is to understand the PV systems performance and degradation along its lifetime. A mathematical model was employed to predict the power output of a real, relatively new operating PV system with respect to environmental parameters temperature, irradiance and cloud coverage. The model used is based on one diode ideality factor and takes into account the parasitic series resistance. The results have been compared with the actual PV output data collected for the year 2014 and show good correlation. As the model predicts the system power output assuming the system in new conditions, the deviation in performance of the real data in comparison to the modeling results need to be further investigated for systems in service for longer time. For this propose, the study presents a condensed review of various causes of degradation in silicon PV modules and techniques to observe and investigate these degradation mechanisms. Major effects on output performance exhibit increase in observed ideality factor n2 and recombination current J02 primarily caused by decrease in minority carrier lifetime, shunts and increase in series resistance. The study further, investigates the governing degradation modes on a ten years old PV crystalline silicon module

  14. Towards a PV-θ view of the general circulation

    Science.gov (United States)

    Hoskins, Brian J.

    1991-09-01

    In recent years, there has been a resurgence of interest in using isentropic coordinates and Rossby-Ertel potential vorticity (PV) for diagnosing the behaviour of middle latitude synoptic systems. Such a PV-θ analysis may also prove important in providing insight into the global circulation of the atmosphere. Apart from the isentropic diagnostic of D. Johnson and collaborators, some quasi-geostrophic studies and recent studies of stratospheric behaviour, there has been little work in this area and our present understanding is very limited. The object of the present paper is to stimulate such studies by presenting some initial results from continuing research. A three-fold division of the atmosphere is discussed. The "Overworld" is the region encompassed by isentropic surfaces that are everywhere above the tropopause. In the "Middleworld", the region with isentropes crossing the tropopause but not striking the Earth's surface, the isentropic zonal and time mean of PV exhibits interesting regions of enhanced and diminished gradients. The isentropic transient eddy advection of PV exhibits a dipolar distribution about the tropopause, suggestive of PV mixing. The marked PV signature of the Asian summer monsoon on one particular Middleworld isentrope is shown and the mean isentropic advection of PV shows interesting features. For the "Underworld", in which isentropic surfaces intercept the surface of the Earth, a PV-θ analysis yields a novel constraint linking low-level drag and diabatic heating. This constraint links "westerlies" and "cooling", and "easterlies" and "heating" in some average sense. The result is discussed in terms of the Southern Hemisphere strong surface westerlies and the circulation associated with the Asian summer and winter monsoons.

  15. Sensitivity to copper in Xanthomonas campestris pv. viticola

    OpenAIRE

    2009-01-01

    ABSTRACT Bacterial canker, caused by Xanthomonas campestris pv. viticola, affects grapevines in the irrigated areas of the São Francisco river valley, in the states of Pernambuco and Bahia. Several practices for disease management have been adopted including copper sprays.This is the only available chemical control method and most frequently used in the areas affected by the disease. The objective of this work was to determine the sensitivity to copper of strains of X. campestris pv. vi...

  16. Microgrid-Ready Solar PV; NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    None

    2015-07-01

    Designing new solar projects to be 'microgrid-ready' enables the U.S. DoD, other federal agencies, and the private sector to plan future microgrid initiatives to utilize solar PV as a generating resource. This fact sheet provides background information with suggested language for several up-front considerations that can be added to a solar project procurement or request for proposal (RFP) that will help ensure that PV systems are built for future microgrid connection.

  17. PV on existing roofs. Experiences of sixty households

    Energy Technology Data Exchange (ETDEWEB)

    Kaan, H.F.; Van Dijk, A.L.; Van Leeuwen, M. [ECN Renewable Energy in the Built Environment DEGO, Petten (Netherlands)

    2001-05-01

    In order to stimulate the use of PV (photovoltaic energy) in the Netherlands, the Dutch government offers a subsidy of 3.40 Euro per Watt peak installed after January 2001. It is hoped that this will facilitate the market for PV systems. The newly to be build houses form a substantial potential as PV carriers, but the existing housing stock is much larger. PV on existing houses has been promoted for several years now in the Netherlands, amongst others by utilities, PV manufacturers and the environmental organization Greenpeace. The new subsidy scheme will undoubtedly have a large impact on the PV demand for existing houses. However, it is doubtful whether the technology is mature enough to meet a large scale demand. In order to learn from experiences with small scale PV systems on roofs of existing houses, the Energy research Centre of the Netherlands (ECN) has set up a research project in which participating employees give access to the roofs of their houses to install PV systems. Fifty-nine ECN employees entered for participation in this project. This group provides a random selection of roofs, so that many different types of roof integration can be examined. Subjects included in the project investigations are: constructional aspects, yield and reliability of systems, institutional aspects such as getting building permits, aesthetics, behavioural aspects. The project was set up in 2000. In April 2001, the installation had been monitored and evaluated. Also the preparatory and initial findings and experiences of project participants have been registered through a questionnaire. The yield of the modules is registered by the participants.

  18. Solar PV Energy Conversion System and its Configurations

    Directory of Open Access Journals (Sweden)

    Ahteshamul Haque

    2016-02-01

    Full Text Available Solar PV based energy conversion system is now used in commercial and residential buildings. Advancements in Power electronics leads the researchers to enhance the use of solar application in various configurations. These configurations may be used to utilize the energy optimally. The main objective of this paper is to present an overview of the various configurations of solar PV energy conversion system

  19. Antagonism of Bacillus spp. against Xanthomonas campestris pv. campestris

    OpenAIRE

    Leila Monteiro; Rosa de Lima Ramos Mariano; Ana Maria Souto-Maior

    2005-01-01

    The antagonism of eight Bacillus isolates was investigated against nine strains of Xanthomonas campestris pv. campestris (causal agent of crucifers black rot) to assess the role of lipopeptides in this process. Antimicrobial and hemolytic (surfactant) activity tests were performed in vitro using agar diffusion methods. Antibiosis and hemolysis were positive for four Bacillus isolates against all X. campestris pv. campestris strains. The correlation observed between antimicrobial and hemolytic...

  20. Natural parasitism of Diaphorina citri Kuwayama (Hemiptera, Psyllidae nymphs by Tamarixia radiata Waterston (Hymenoptera, Eulophidae in São Paulo orange groves Parasitismo natural de ninfas de Diaphorina citri Kuwayama (Hemiptera, Psyllidae por Tamarixia radiata Waterston (Hymenoptera, Eulophidae em pomares de laranja em São Paulo

    Directory of Open Access Journals (Sweden)

    Paulo Eduardo Branco Paiva

    2012-12-01

    Full Text Available The psyllid Diaphorina citri Kuwayama 1908 has become the main citrus pest species in the state of São Paulo, Brazil, after the introduction of the huanglongbing or citrus greening. This study evaluated the parasitism of 3rd, 4th and 5th instar D. citri nymphs by Tamarixia radiata (Waterston, 1922 in citrus groves under a regimen of regular insecticide applications in ten producing regions: Araraquara, Barretos, Bauru, Botucatu, Franca, Itapetininga, Jaú, Limeira, Lins and São João da Boa Vista. Sixty-nine samples of new branches infested with nymphs of D. citri were collected from 2005 to 2008 in orange groves ranging from 1 to 20 years old, of the varieties Hamlin, Pera, Valencia and Natal. The parasitoid T. radiata is widely distributed in São Paulo orange groves, and was identified in 50 (72% of the samples, showing a mean parasitism rate of 12.4%. The highest parasitism rate was observed in the "summer" (from January through March, with a mean of 25.7%. Nymphal parasitism was above 90% in two samples. The probable causes of the variations in parasitism of D. citri by T. radiata are discussed.O psilídeo Diaphorina citri Kuwayama 1908 tornou-se a principal praga dos citros no estado de São Paulo após a introdução do huanglongbing ou grenning dos citros. Este estudo avaliou as proporções de ninfas de terceiro a quinto ínstares de D. citri parasitadas por Tamarixia radiata (Waterston, 1922 em pomares de laranja submetidos a pulverizações constantes de inseticidas em dez regiões produtoras, Araraquara, Barretos, Bauru, Botucatu, Franca, Itapetininga, Jaú, Limeira, Lins e São João da Boa Vista. Foram coletadas 69 amostras de ramos jovens infestados com ninfas de D. citri obtidas entre 2005 e 2008 em pomares de 1 a 20 anos de idade, das cultivares Hamilin, Pera, Valencia e Natal. O parasitóide T. radiata encontra-se amplamente distribuído em pomares de São Paulo, tendo sido observado em 50 amostras (72%, com taxa média de

  1. Parallel experimental study of a novel super-thin thermal absorber based photovoltaic/thermal (PV/T system against conventional photovoltaic (PV system

    Directory of Open Access Journals (Sweden)

    Peng Xu

    2015-11-01

    Full Text Available Photovoltaic (PV semiconductor degrades in performance due to temperature rise. A super thin-conductive thermal absorber is therefore developed to regulate the PV working temperature by retrofitting the existing PV panel into the photovoltaic/thermal (PV/T panel. This article presented the parallel comparative investigation of the two different systems through both laboratory and field experiments. The laboratory evaluation consisted of one PV panel and one PV/T panel respectively while the overall field system involved 15 stand-alone PV panels and 15 retrofitted PV/T panels. The laboratory testing results demonstrated the PV/T panel could achieve the electrical efficiency of about 16.8% (relatively 5% improvement comparing with the stand-alone PV panel, and yield an extra amount of heat with thermal efficiency of nearly 65%. The field testing results indicated that the hybrid PV/T panel could enhance the electrical return of PV panels by nearly 3.5%, and increase the overall energy output by nearly 324.3%. Further opportunities and challenges were then discussed from aspects of different PV/T stakeholders to accelerate the development. It is expected that such technology could become a significant solution to yield more electricity, offset heating load freely and reduce carbon footprint in contemporary energy environment.

  2. PV Derived Data for Predicting Performance; NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Marion, Bill

    2015-09-14

    A method is described for providing solar irradiance data for modeling PV performance by using measured PV performance data and back-solving for the unknown direct normal irradiance (DNI) and diffuse horizontal irradiance (DHI), which can then be used to model the performance of PV systems of any size, PV array tilt, or PV array azimuth orientation. Ideally situated for using the performance data from PV modules with micro-inverters, the PV module operating current is used to determine the global tilted irradiance (GTI), and a separation model is then used to determine the DNI and DHI from the GTI.

  3. PV Derived Data for Predicting Performance; NREL (National Renewable Energy Laboratory)

    Energy Technology Data Exchange (ETDEWEB)

    Marion, Bill

    2015-09-14

    A method is described for providing solar irradiance data for modeling PV performance by using measured PV performance data and back-solving for the unknown direct normal irradiance (DNI) and diffuse horizontal irradiance (DHI), which can then be used to model the performance of PV systems of any size, PV array tilt, or PV array azimuth orientation. Ideally situated for using the performance data from PV modules with micro-inverters, the PV module operating current is used to determine the global tilted irradiance (GTI), and a separation model is then used to determine the DNI and DHI from the GTI.

  4. Pathogenesis of motor neuron disease

    Institute of Scientific and Technical Information of China (English)

    Xuefei Wang

    2006-01-01

    OBJECTIVE: To summarize and analyze the factors and theories related to the attack of motor neuron disease, and comprehensively investigate the pathogenesis of motor neuron disease.DATA SOURCES: A search of Pubmed database was undertaken to identify articles about motor neuron disease published in English from January 1994 to June 2006 by using the keywords of "neurodegenerative diseases". Other literatures were collected by retrieving specific journals and articles.STUDY SELECTION: The data were checked primarily, articles related to the pathogenesis of motor neuron disease were involved, and those obviously irrelated to the articles were excluded.DATA EXTRACTION: Totally 54 articles were collected, 30 of them were involved, and the other 24 were excluded.DATA SYNTHESIS: The pathogenesis of motor neuron disease has multiple factors, and the present related theories included free radical oxidation, excitotoxicity, genetic and immune factors, lack of neurotrophic factor,injury of neurofilament, etc. The studies mainly come from transgenic animal models, cell culture in vitro and patients with familial motor neuron disease, but there are still many restrictions and disadvantages.CONCLUSION: It is necessary to try to find whether there is internal association among different mechanisms,comprehensively investigate the pathogenesis of motor neuron diseases, in order to provide reliable evidence for the clinical treatment.

  5. On the pathogenesis of IDDM

    DEFF Research Database (Denmark)

    Nerup, J; Mandrup-Poulsen, Thomas; Helqvist, S

    1994-01-01

    A model of the pathogenesis of insulin-dependent diabetes mellitus, i.e. the initial phase of beta-cell destruction, is proposed: in a cascade-like fashion efficient antigen presentation, unbalanced cytokine, secretion and poor beta-cell defence result in beta-cell destruction by toxic free...

  6. Progress in Pathogenesis of Proteinuria

    Directory of Open Access Journals (Sweden)

    Aihua Zhang

    2012-01-01

    Full Text Available Aims. Proteinuria not only is a sign of kidney damage, but also is involved in the progression of renal diseases as an independent pathologic factor. Clinically, glomerular proteinuria is most commonly observed, which relates to structural and functional anomalies in the glomerular filtration barrier. The aim of this paper was to describe the pathogenesis of glomerular proteinuria. Data Sources. Articles on glomerular proteinuria retrieved from Pubmed and MEDLINE in the recent 5 years were reviewed. Results. The new understanding of the roles of glomerular endothelial cells and the glomerular basement membrane (GBM in the pathogenesis of glomerular proteinuria was gained. The close relationships of slit diaphragm (SD molecules such as nephrin, podocin, CD2-associated protein (CD2AP, a-actinin-4, transient receptor potential cation channel 6 (TRPC6, Densin and membrane-associated guanylate kinase inverted 1 (MAGI-1, α3β1 integrin, WT1, phospholipase C epsilon-1 (PLCE1, Lmx1b, and MYH9, and mitochondrial disorders and circulating factors in the pathogenesis of glomerular proteinuria were also gradually discovered. Conclusion. Renal proteinuria is a manifestation of glomerular filtration barrier dysfunction. Not only glomerular endothelial cells and GBM, but also the glomerular podocytes and their SDs play an important role in the pathogenesis of glomerular proteinuria.

  7. Pathogenesis of postoperative adhesion formation

    NARCIS (Netherlands)

    Hellebrekers, B.W.J.; Kooistra, T.

    2011-01-01

    Background: Current views on the pathogenesis of adhesion formation are based on the "classical concept of adhesion formation", namely that a reduction in peritoneal fibrinolytic activity following peritoneal trauma is of key importance in adhesion development. Methods: A non-systematic literature

  8. Biology and pathogenesis of Acanthamoeba

    OpenAIRE

    Siddiqui Ruqaiyyah; Khan Naveed

    2012-01-01

    Abstract Acanthamoeba is a free-living protist pathogen, capable of causing a blinding keratitis and fatal granulomatous encephalitis. The factors that contribute to Acanthamoeba infections include parasite biology, genetic diversity, environmental spread and host susceptibility, and are highlighted together with potential therapeutic and preventative measures. The use of Acanthamoeba in the study of cellular differentiation mechanisms, motility and phagocytosis, bacterial pathogenesis and ev...

  9. Design optimization of transformerless grid-connected PV inverters including reliability

    DEFF Research Database (Denmark)

    Koutroulis, Eftichios; Blaabjerg, Frede

    2012-01-01

    This paper presents a new methodology for optimal design of transformerless Photovoltaic (PV) inverters targeting a cost-effective deployment of grid-connected PV systems. The optimal values and types of the PV inverter components are calculated such that the PV inverter Levelized Cost Of the Ele......This paper presents a new methodology for optimal design of transformerless Photovoltaic (PV) inverters targeting a cost-effective deployment of grid-connected PV systems. The optimal values and types of the PV inverter components are calculated such that the PV inverter Levelized Cost...... to the non-optimized PV inverter structures, the PV inverters designed using the proposed optimization methodology exhibit lower total manufacturing and lifetime maintenance cost and inject more energy into the electric-grid and by that minimizing LCOE....

  10. Continuing Developments in PV Risk Management: Strategies, Solutions, and Implications

    Energy Technology Data Exchange (ETDEWEB)

    Lowder, T.; Mendelsohn, M.; Speer, B.; Hill, R.

    2013-02-01

    As the PV industry matures, successful risk management practices will become more imperative to ensure investor confidence, control costs, and facilitate further growth. This report discusses several key aspects of risk management during the commercial- and utility-scale project life cycle, from identification of risks, to the process of mitigating and allocating those risks among project parties, to transferring those risks through insurance. The report also explores novel techniques in PV risk management, options to offload risks onto the capital markets, and innovative insurance policies (namely warranty policies) that address risks unique to the PV sector. One of the major justifications for robust risk management in the PV industry is the cost-reduction opportunities it affords. If the PV industry can demonstrate the capability to successfully manage its risks, thereby inspiring confidence in financiers, it may be able to obtain a lower cost of capital in future transactions. A lower cost of capital translates to a lower cost of energy, which will in turn enhance PV?s competitiveness at a time when it will have to rely less on subsidies to support its market penetration.

  11. Integrating High Penetrations of PV into Southern California

    Energy Technology Data Exchange (ETDEWEB)

    Kroposki, B.; Mather, B.; Hasper-Tuttle, J.; Neal, R.; Katiraei, F.; Yazdani, A.; Aguero, J. R.; Hoff, T. E.; Norris, B. L.; Parkins, A.; Seguin, R.; Schauder, C.

    2011-01-01

    California regulators recently approved a plan proposed by Southern California Edison (SCE) to install 500 MW of distributed photovoltaic (PV) energy in its utility service territory over the next 5 years. The installations will include 250 MW of utility-owned solar and 250 MW of independently owned solar. SCE expects that the majority of these systems will be commercial-scale rooftop PV systems connected at various points in the distribution system. Each of the SCE rooftop PV systems will typically have a rating of 1-3 MW. To understand the impact of high-penetration PV on the distribution grid, the National Renewable Energy Laboratory (NREL) and SCE brought together a team of experts in resource assessment, distribution modeling, and planning to help analyze the impacts of adding high penetration of PV into the distribution system. Through modeling and simulation, laboratory testing, and field demonstrations, the team will address the issues identified in the analysis by fully examining the challenges, developing solutions, and transitioning those solutions to the field for large-scale deployment. This paper gives an update on the project and discusses technical results of integrating a large number of distributed PV systems into the grid.

  12. Review of Artificial Abrasion Test Methods for PV Module Technology

    Energy Technology Data Exchange (ETDEWEB)

    Miller, David C. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Muller, Matt T. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Simpson, Lin J. [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-08-01

    This review is intended to identify the method or methods--and the basic details of those methods--that might be used to develop an artificial abrasion test. Methods used in the PV literature were compared with their closest implementation in existing standards. Also, meetings of the International PV Quality Assurance Task Force Task Group 12-3 (TG12-3, which is concerned with coated glass) were used to identify established test methods. Feedback from the group, which included many of the authors from the PV literature, included insights not explored within the literature itself. The combined experience and examples from the literature are intended to provide an assessment of the present industry practices and an informed path forward. Recommendations toward artificial abrasion test methods are then identified based on the experiences in the literature and feedback from the PV community. The review here is strictly focused on abrasion. Assessment methods, including optical performance (e.g., transmittance or reflectance), surface energy, and verification of chemical composition were not examined. Methods of artificially soiling PV modules or other specimens were not examined. The weathering of artificial or naturally soiled specimens (which may ultimately include combined temperature and humidity, thermal cycling and ultraviolet light) were also not examined. A sense of the purpose or application of an abrasion test method within the PV industry should, however, be evident from the literature.

  13. Performance evaluation of stand alone hybrid PV-wind generator

    Science.gov (United States)

    Nasir, M. N. M.; Saharuddin, N. Z.; Sulaima, M. F.; Jali, Mohd Hafiz; Bukhari, W. M.; Bohari, Z. H.; Yahaya, M. S.

    2015-05-01

    This paper presents the performance evaluation of standalone hybrid system on Photovoltaic (PV)-Wind generator at Faculty of Electrical Engineering (FKE), UTeM. The hybrid PV-Wind in UTeM system is combining wind turbine system with the solar system and the energy capacity of this hybrid system can generate up to charge the battery and supply the LED street lighting load. The purpose of this project is to evaluate the performance of PV-Wind hybrid generator. Solar radiation meter has been used to measure the solar radiation and anemometer has been used to measure the wind speed. The effectiveness of the PV-Wind system is based on the various data that has been collected and compared between them. The result shows that hybrid system has greater reliability. Based on the solar result, the correlation coefficient shows strong relationship between the two variables of radiation and current. The reading output current followed by fluctuate of solar radiation. However, the correlation coefficient is shows moderate relationship between the two variables of wind speed and voltage. Hence, the wind turbine system in FKE show does not operate consistently to produce energy source for this hybrid system compare to PV system. When the wind system does not fully operate due to inconsistent energy source, the other system which is PV will operate and supply the load for equilibrate the extra load demand.

  14. Review of PV Inverter Technology Cost and Performance Projections

    Energy Technology Data Exchange (ETDEWEB)

    Navigant Consulting Inc.

    2006-01-01

    The National Renewable Energy Laboratory (NREL) has a major responsibility in the implementation of the U.S. Department of Energy's (DOE's) Solar Energy Technologies Program. Sandia National Laboratories (SNL) has a major role in supporting inverter development, characterization, standards, certifications, and verifications. The Solar Energy Technologies Program recently published a Multiyear Technical Plan, which establishes a goal of reducing the Levelized Energy Cost (LEC) for photovoltaic (PV) systems to $0.06/kWh by 2020. The Multiyear Technical Plan estimates that, in order to meet the PV system goal, PV inverter prices will need to decline to $0.25-0.30 Wp by 2020. DOE determined the need to conduct a rigorous review of the PV Program's technical and economic targets, including the target set for PV inverters. NREL requested that Navigant Consulting Inc.(NCI) conduct a review of historical and projected cost and performance improvements for PV inverters, including identification of critical barriers identified and the approaches government might use to address them.

  15. Battery Energy Storage System for PV Output Power Leveling

    Directory of Open Access Journals (Sweden)

    Rajkiran Singh

    2014-01-01

    Full Text Available Fluctuating photovoltaic (PV output power reduces the reliability in power system when there is a massive penetration of PV generators. Energy storage systems that are connected to the PV generators using bidirectional isolated dc-dc converter can be utilized for compensating the fluctuating PV power. This paper presents a grid connected energy storage system based on a 2 kW full-bridge bidirectional isolated dc-dc converter and a PWM converter for PV output power leveling. This paper proposes two controllers: a current controller using the d-q synchronous reference and a phase-shift controller. The main function of the current controller is to regulate the voltage at the high-side dc, so that the voltage ratio of the high-voltage side (HVS with low-voltage side (LVS is equal to the transformer turns ratio. The phase-shift controller is employed to manage the charging and discharging modes of the battery based on PV output power and battery voltage. With the proposed system, unity power factor and efficient active power injection are achieved. The feasibility of the proposed control system is investigated using PSCAD simulation.

  16. Residential Solar PV Systems in the Carolinas: Opportunities and Outcomes.

    Science.gov (United States)

    Alqahtani, Bandar Jubran; Holt, Kyra Moore; Patiño-Echeverri, Dalia; Pratson, Lincoln

    2016-02-16

    This paper presents a first-order analysis of the feasibility and technical, environmental, and economic effects of large levels of solar photovoltaic (PV) penetration within the services areas of the Duke Energy Carolinas (DEC) and Duke Energy Progress (DEP). A PV production model based on household density and a gridded hourly global horizontal irradiance data set simulates hourly PV power output from roof-top installations, while a unit commitment and real-time economic dispatch (UC-ED) model simulates hourly system operations. We find that the large generating capacity of base-load nuclear power plants (NPPs) without ramping capability in the region limits PV integration levels to 5.3% (6510 MW) of 2015 generation. Enabling ramping capability for NPPs would raise the limit of PV penetration to near 9% of electricity generated. If the planned retirement of coal-fired power plants together with new installations and upgrades of natural gas and nuclear plants materialize in 2025, and if NPPs operate flexibly, then the share of coal-fired electricity will be reduced from 37% to 22%. A 9% penetration of electricity from PV would further reduce the share of coal-fired electricity by 4-6% resulting in a system-wide CO2 emissions rate of 0.33 to 0.40 tons/MWh and associated abatement costs of 225-415 (2015$ per ton).

  17. Control Strategies for the DAB Based PV Interface System.

    Science.gov (United States)

    El-Helw, Hadi M; Al-Hasheem, Mohamed; Marei, Mostafa I

    2016-01-01

    This paper presents an interface system based on the Dual Active Bridge (DAB) converter for Photovoltaic (PV) arrays. Two control strategies are proposed for the DAB converter to harvest the maximum power from the PV array. The first strategy is based on a simple PI controller to regulate the terminal PV voltage through the phase shift angle of the DAB converter. The Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) technique is utilized to set the reference of the PV terminal voltage. The second strategy presented in this paper employs the Artificial Neural Network (ANN) to directly set the phase shift angle of the DAB converter that results in harvesting maximum power. This feed-forward strategy overcomes the stability issues of the feedback strategy. The proposed PV interface systems are modeled and simulated using MATLAB/SIMULINK and the EMTDC/PSCAD software packages. The simulation results reveal accurate and fast response of the proposed systems. The dynamic performance of the proposed feed-forward strategy outdoes that of the feedback strategy in terms of accuracy and response time. Moreover, an experimental prototype is built to test and validate the proposed PV interface system.

  18. Control Strategies for the DAB Based PV Interface System

    Science.gov (United States)

    El-Helw, Hadi M.; Al-Hasheem, Mohamed; Marei, Mostafa I.

    2016-01-01

    This paper presents an interface system based on the Dual Active Bridge (DAB) converter for Photovoltaic (PV) arrays. Two control strategies are proposed for the DAB converter to harvest the maximum power from the PV array. The first strategy is based on a simple PI controller to regulate the terminal PV voltage through the phase shift angle of the DAB converter. The Perturb and Observe (P&O) Maximum Power Point Tracking (MPPT) technique is utilized to set the reference of the PV terminal voltage. The second strategy presented in this paper employs the Artificial Neural Network (ANN) to directly set the phase shift angle of the DAB converter that results in harvesting maximum power. This feed-forward strategy overcomes the stability issues of the feedback strategy. The proposed PV interface systems are modeled and simulated using MATLAB/SIMULINK and the EMTDC/PSCAD software packages. The simulation results reveal accurate and fast response of the proposed systems. The dynamic performance of the proposed feed-forward strategy outdoes that of the feedback strategy in terms of accuracy and response time. Moreover, an experimental prototype is built to test and validate the proposed PV interface system. PMID:27560138

  19. Performance evaluation of stand alone hybrid PV-wind generator

    Energy Technology Data Exchange (ETDEWEB)

    Nasir, M. N. M.; Saharuddin, N. Z.; Sulaima, M. F.; Jali, Mohd Hafiz; Bukhari, W. M.; Bohari, Z. H. [Faculty of Electrical Engineering, Universiti Teknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 76100 Melaka (Malaysia); Yahaya, M. S. [Faculty of Engineering Technology, Universiti Teknikal Malaysia Melaka (UTeM), Hang Tuah Jaya, 76100 Melaka (Malaysia)

    2015-05-15

    This paper presents the performance evaluation of standalone hybrid system on Photovoltaic (PV)-Wind generator at Faculty of Electrical Engineering (FKE), UTeM. The hybrid PV-Wind in UTeM system is combining wind turbine system with the solar system and the energy capacity of this hybrid system can generate up to charge the battery and supply the LED street lighting load. The purpose of this project is to evaluate the performance of PV-Wind hybrid generator. Solar radiation meter has been used to measure the solar radiation and anemometer has been used to measure the wind speed. The effectiveness of the PV-Wind system is based on the various data that has been collected and compared between them. The result shows that hybrid system has greater reliability. Based on the solar result, the correlation coefficient shows strong relationship between the two variables of radiation and current. The reading output current followed by fluctuate of solar radiation. However, the correlation coefficient is shows moderate relationship between the two variables of wind speed and voltage. Hence, the wind turbine system in FKE show does not operate consistently to produce energy source for this hybrid system compare to PV system. When the wind system does not fully operate due to inconsistent energy source, the other system which is PV will operate and supply the load for equilibrate the extra load demand.

  20. PVMirrors: Hybrid PV/CSP collectors that enable lower LCOEs

    Science.gov (United States)

    Fisher, Kate; Yu, Zhengshan Jason; Striling, Rob; Holman, Zachary

    2017-06-01

    The primary challenge with concentrating solar power (CSP) is that the conversion efficiency is low—and the cost high—compared to that of photovoltaics (PV), and the primary challenge with PV is that the energy generated cannot be stored cost effectively. We introduce a technology that hybridizes CSP and PV, resulting in power plants with high energy conversion efficiency and affordable storage. This is accomplished by replacing silvered troughs (or heliostat facets) with "PVMirrors" that and direct photons of each wavelength to the converter (PV or thermal) that may best use them. A PVMirror looks like a curved PV module that includes a spectrum-splitting dichroic mirror film; this film, which is the heart of the technology, transmits near-infrared light to the underlying silicon PV cells while reflecting both longer and shorter wavelengths to a thermal absorber tube. This paper investigates the optical performance of dichroic mirror film, the specularity of PVMirrors, and the anticipated levelized cost of energy (LCOE) from a PVMirror power plant. PVMirrors are found to decrease LCOE by more than 15% relative to CSP while retaining full dispatchability.

  1. A Software Tool for Optimal Sizing of PV Systems in Malaysia

    OpenAIRE

    Tamer Khatib; Azah Mohamed; K. Sopian

    2012-01-01

    This paper presents a MATLAB based user friendly software tool called as PV.MY for optimal sizing of photovoltaic (PV) systems. The software has the capabilities of predicting the metrological variables such as solar energy, ambient temperature and wind speed using artificial neural network (ANN), optimizes the PV module/ array tilt angle, optimizes the inverter size and calculate optimal capacities of PV array, battery, wind turbine and diesel generator in hybrid PV systems. The ANN based mo...

  2. Investigation of the Effect Temperature on Photovoltaic (PV) Panel Output Performance

    OpenAIRE

    Amelia Razak; Y.M. Irwan; W.Z. Leow; M Irwanto; I. Safwati; M. Zhafarina

    2016-01-01

    The main limit of PV systems is the low conversion efficiency of PV panels, which is strongly influenced by their operating temperature. Lack of accuracy in consideration through PV panel temperature increases the financial risk of system installation. This present study investigates the effects of operating temperature on monocrystalline PV panel at Perlis, Malaysia. A selected model of PV panel firstly was simulated using PVSYST software in order to evaluate its output performance. Meanwhil...

  3. Resistance inducers modulate Pseudomonas syringae pv. tomato strain DC3000 response in tomato plants.

    Directory of Open Access Journals (Sweden)

    Loredana Scalschi

    Full Text Available The efficacy of hexanoic acid (Hx as an inducer of resistance in tomato plants against Pseudomonas syringae pv. tomato DC3000 was previously demonstrated, and the plant response was characterized. Because little is known about the reaction of the pathogen to this effect, the goal of the present work was to determine whether the changes in the plant defence system affect the pathogen behaviour. This work provides the first demonstration of the response of the pathogen to the changes observed in plants after Hx application in terms of not only the population size but also the transcriptional levels of genes involved in quorum sensing establishment and pathogenesis. Therefore, it is possible that Hx treatment attenuates the virulence and survival of bacteria by preventing or diminishing the appearance of symptoms and controlling the growth of the bacteria in the mesophyll. It is interesting to note that the gene transcriptional changes in the bacteria from the treated plants occur at the same time as the changes in the plants. Hx is able to alter bacteria pathogenesis and survival only when it is applied as a resistance inducer because the changes that it promotes in plants affect the bacteria.

  4. Resistance Inducers Modulate Pseudomonas syringae pv. Tomato Strain DC3000 Response in Tomato Plants

    Science.gov (United States)

    Scalschi, Loredana; Camañes, Gemma; Llorens, Eugenio; Fernández-Crespo, Emma; López, María M.; García-Agustín, Pilar; Vicedo, Begonya

    2014-01-01

    The efficacy of hexanoic acid (Hx) as an inducer of resistance in tomato plants against Pseudomonas syringae pv. tomato DC3000 was previously demonstrated, and the plant response was characterized. Because little is known about the reaction of the pathogen to this effect, the goal of the present work was to determine whether the changes in the plant defence system affect the pathogen behaviour. This work provides the first demonstration of the response of the pathogen to the changes observed in plants after Hx application in terms of not only the population size but also the transcriptional levels of genes involved in quorum sensing establishment and pathogenesis. Therefore, it is possible that Hx treatment attenuates the virulence and survival of bacteria by preventing or diminishing the appearance of symptoms and controlling the growth of the bacteria in the mesophyll. It is interesting to note that the gene transcriptional changes in the bacteria from the treated plants occur at the same time as the changes in the plants. Hx is able to alter bacteria pathogenesis and survival only when it is applied as a resistance inducer because the changes that it promotes in plants affect the bacteria. PMID:25244125

  5. Proposal of Xanthomonas translucens pv. pistaciae pv. nov., pathogenic to pistachio (Pistacia vera).

    Science.gov (United States)

    Giblot-Ducray, Danièle; Marefat, Alireza; Gillings, Michael R; Parkinson, Neil M; Bowman, John P; Ophel-Keller, Kathy; Taylor, Cathy; Facelli, Evelina; Scott, Eileen S

    2009-12-01

    Strains of Xanthomonas translucens have caused dieback in the Australian pistachio industry for the last 15 years. Such pathogenicity to a dicotyledonous woody host contrasts with that of other pathovars of X. translucens, which are characterized by their pathogenicity to monocotyledonous plant families. Further investigations, using DNA-DNA hybridization, gyrB gene sequencing and integron screening, were conducted to confirm the taxonomic status of the X. translucens pathogenic to pistachio. DNA-DNA hybridization provided a clear classification, at the species level, of the pistachio pathogen as a X. translucens. In the gyrB-based phylogeny, strains of the pistachio pathogen clustered among the X. translucens pathovars as two distinct lineages. Integron screening revealed that the cassette arrays of strains of the pistachio pathogen were different from those of other Xanthomonas species, and again distinguished two groups. Together with previously reported pathogenicity data, these results confirm that the pistachio pathogen is a new pathovar of X. translucens and allow hypotheses about its origin. The proposed name is Xanthomonas translucens pv. pistaciae pv. nov.

  6. Antitussive, expectorant and anti-inflammatory activities of different extracts from Exocarpium Citri grandis.

    Science.gov (United States)

    Jiang, Kun; Song, Qian; Wang, Lei; Xie, Tianzhu; Wu, Xi; Wang, Ping; Yin, Guo; Ye, Wencai; Wang, Tiejie

    2014-10-28

    Exocarpium Citri grandis (C. grandis, Huajuhong in Chinese), the epicarp of C. grandis 'Tomentosa', is used as an antitussive, expectorant and anti-inflammatory drug for hundreds of years in China. The study was aimed at evaluating the antitussive, expectorant and anti-inflammatory effects of different extracts of C. grandis, providing experimental evidence for its traditional use, and laying a foundation for its further researches. Crude drugs of C. grandis were extracted with four kinds of solvents (water, 50% ethanol, 70% ethanol and 90% ethanol) in reflux conditions, respectively. Solutions were concentrated in reduced pressure and lyophilized in vacuum to yield the aqueous extract, 50% ethanolic extract, 70% ethanolic extract, and 90% ethanolic extract of C. grandis. Antitussive evaluations were carried out with ammonia liquor induced mice cough; expectorant effects were tested with phenol red secretion experiments in mice; anti-inflammatory effects were assessed by murine model of xylene induced ear edema in mice. Only aqueous and 70% ethanolic extracts of C. grandis displayed significant antitussive, expectorant and anti-inflammatory activities. Aqueous extract of C. grandis significantly decreased cough frequency caused by ammonia liquor, increased phenol red secretion and inhibited the development of ear edema in anti-inflammatory assay at the dose of 1005 mg/kg (Pstrong effect of decreasing cough frequency, prolonging cough period, increasing phenol red secretion and decreasing the extent of ear edema at the dose of 493 mg/kg (P<0.001). The low, middle, and high dose (247, 493, and 986 mg/kg) of 70% ethanolic extract of C. grandis showed significant antitussive, expectorant and anti-inflammatory effects in good dose dependant manner. The results supported the folk use of C. grandis (decoction of C. grandis) with scientific evidence, and indicated that the 70% ethanolic extract of C. grandis might have better effects of antitussive, expectorant and anti

  7. Large scale PV plants - also in Denmark. Project report

    Energy Technology Data Exchange (ETDEWEB)

    Ahm, P. (PA Energy, Malling (Denmark)); Vedde, J. (SiCon. Silicon and PV consulting, Birkeroed (Denmark))

    2011-04-15

    Large scale PV (LPV) plants, plants with a capacity of more than 200 kW, has since 2007 constituted an increasing share of the global PV installations. In 2009 large scale PV plants with cumulative power more that 1,3 GWp were connected to the grid. The necessary design data for LPV plants in Denmark are available or can be found, although irradiance data could be improved. There seems to be very few institutional barriers for LPV projects, but as so far no real LPV projects have been processed, these findings have to be regarded as preliminary. The fast growing number of very large scale solar thermal plants for district heating applications supports these findings. It has further been investigated, how to optimize the lay-out of LPV plants. Under the Danish irradiance conditions with several winter months with very low solar height PV installations on flat surfaces will have to balance the requirements of physical space - and cost, and the loss of electricity production due to shadowing effects. The potential for LPV plants in Denmark are found in three main categories: PV installations on flat roof of large commercial buildings, PV installations on other large scale infrastructure such as noise barriers and ground mounted PV installations. The technical potential for all three categories is found to be significant and in the range of 50 - 250 km2. In terms of energy harvest PV plants will under Danish conditions exhibit an overall efficiency of about 10 % in conversion of the energy content of the light compared to about 0,3 % for biomass. The theoretical ground area needed to produce the present annual electricity consumption of Denmark at 33-35 TWh is about 300 km2 The Danish grid codes and the electricity safety regulations mention very little about PV and nothing about LPV plants. It is expected that LPV plants will be treated similarly to big wind turbines. A number of LPV plant scenarios have been investigated in detail based on real commercial offers and

  8. Silencing and heterologous expression of ppo-2 indicate a specific function of a single polyphenol oxidase isoform in resistance of dandelion (Taraxacum officinale) against Pseudomonas syringae pv. tomato.

    Science.gov (United States)

    Richter, Carolin; Dirks, Mareike E; Gronover, Christian Schulze; Prüfer, Dirk; Moerschbacher, Bruno M

    2012-02-01

    Dandelion (Taraxacum officinale) possesses an unusually high degree of disease resistance. As this plant exhibits high polyphenol oxidase (PPO) activity and PPO have been implicated in resistance against pests and pathogens, we analyzed the potential involvement of five PPO isoenzymes in the resistance of dandelion against Botrytis cinerea and Pseudomonas syringae pv. tomato. Only one PPO (ppo-2) was induced during infection, and ppo-2 promoter and β-glucuronidase marker gene fusions revealed strong induction of the gene surrounding lesions induced by B. cinerea. Specific RNAi silencing reduced ppo-2 expression only, and concomitantly increased plant susceptibility to P. syringae pv. tomato. At 4 days postinoculation, P. syringae pv. tomato populations were strongly increased in the ppo-2 RNAi lines compared with wild-type plants. When the dandelion ppo-2 gene was expressed in Arabidopsis thaliana, a plant having no PPO gene, active protein was formed and protein extracts of the transgenic plants exhibited substrate-dependent antimicrobial activity against P. syringae pv. tomato. These results clearly indicate a strong contribution of a specific, single PPO isoform to disease resistance. Therefore, we propose that specific PPO isoenzymes be included in a new family of pathogenesis-related (PR) proteins.

  9. The RpfB-Dependent Quorum Sensing Signal Turnover System Is Required for Adaptation and Virulence in Rice Bacterial Blight Pathogen Xanthomonas oryzae pv. oryzae.

    Science.gov (United States)

    Wang, Xing-Yu; Zhou, Lian; Yang, Jun; Ji, Guang-Hai; He, Ya-Wen

    2016-03-01

    Xanthomonas oryzae pv. oryzae, the bacterial blight pathogen of rice, produces diffusible signal factor (DSF) family quorum sensing signals to regulate virulence. The biosynthesis and perception of DSF family signals require components of the rpf (regulation of pathogenicity factors) cluster. In this study, we report that RpfB plays an essential role in DSF family signal turnover in X. oryzae pv. oryzae PXO99A. The production of DSF family signals was boosted by deletion of the rpfB gene and was abolished by its overexpression. The RpfC/RpfG-mediated DSF signaling system negatively regulates rpfB expression via the global transcription regulator Clp, whose activity is reversible in the presence of cyclic diguanylate monophosphate. These findings indicate that the DSF family signal turnover system in PXO99A is generally consistent with that in Xanthomonas campestris pv. campestris. Moreover, this study has revealed several specific roles of RpfB in PXO99A. First, the rpfB deletion mutant produced high levels of DSF family signals but reduced extracellular polysaccharide production, extracellular amylase activity, and attenuated pathogenicity. Second, the rpfB/rpfC double-deletion mutant was partially deficient in xanthomonadin production. Taken together, the RpfB-dependent DSF family signal turnover system is a conserved and naturally presenting signal turnover system in Xanthomonas spp., which plays unique roles in X. oryzae pv. oryzae adaptation and pathogenesis.

  10. PV-HYBRID and MINI-GRID. Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    Within the 3rd European Conference at the Centre de Congres in Aix en Provence (France) between 11th and 12th May, 2006, the following lessons were held: (1) Small electric networks: European drivers and projects for the integration of RES and DG into the electricity grids of the future (Manuel Sanchez-Jimenez); (2) PV hybrid system within mini grids - IEA PVPS programme (Meuch Konraf); (3) Renewables for the developing world (Alvaro Ponce Plaza); (4) Rural electicity supply using photovoltaic / - Diesel hybrid systems: Attractive for investors in the renewable energy sector? (Andreas Hahn); (5) Economic analysis of stand-alone and grid-connected photovoltaic systems under current tariff structure of Taiwan (Yaw-Juen Wang); (6) Using wind-PV-diesel hybrid system for electrification of remote village in Western Libya (N.M. Kreama); (7) Venezuela's renewable energy program for small towns and rural areas ''Sembrando Luz'' (Jorge Torres); (8) AeroSmart5, the professional, sysem-compatible small-scale wind energy converter will be tested in field tests (Fabian Jochem); (9) Lifetime, test procedures and recommendations for optimal operating strategies for lead-acid-batteries in renewable energy systems - A survey on results from European projects from the 5th framework programme (Rudi Kaiser); (10) Prototype of a reversible fuel cell system for autonomous power supplies (Tom Smolinska); (11) Interconnection management in microgrids (Michel Vandenbergh); (12) Control strategy for a small-scale stand-alone power system based on renewable energy and hydrogen (Harald Miland); (13) Standard renewable electricity supply for people in rural areas - mini-grids in western provinces of China (Michael Wollny); (14) The Brava island a ''100% renewable energy'' project (Jean-Christian Marcel); (15) Breakthrough to a new era of PV-hybrid systems with the help of standardised components communication? (Michael Mueller); (16) Standardized

  11. Performance of a 34 kWp grid-connected PV system in Indonesia - A comparison of tropical and European PV systems

    NARCIS (Netherlands)

    Veldhuis, A.J.; Reinders, A.H.M.E.

    2014-01-01

    We analysed a monitored grid-connected PV system of 34 kWp in Indonesia to investigate the performance of PV systems in tropical climates. The PV system has been installed in Jayapura, the capital of the Province of Papua, Indonesia, by the beginning of 2012. Due to the aged gensets and frequent lac

  12. Plug and Play PV Systems for American Homes

    Energy Technology Data Exchange (ETDEWEB)

    Hoepfner, Christian [Fraunhofer USA, Inc., Boston, MA (United States)

    2016-12-22

    The core objectives of the Plug & Play PV Systems Project were to develop a PV system that can be installed on a residential rooftop for less than $1.50/W in 2020, and in less than 10 hours (from point of purchase to commissioning). The Fraunhofer CSE team’s approach to this challenge involved a holistic approach to system design – hardware and software – that make Plug & Play PV systems: • Quick, easy, and safe to install • Easy to demonstrate as code compliant • Permitted, inspected, and interconnected via an electronic process Throughout the three years of work during this Department of Energy SunShot funded project, the team engaged in a substantive way with inspectional services departments and utilities, manufacturers, installers, and distributors. We received iterative feedback on the system design and on ideas for how such systems can be commercialized. This ultimately led us to conceiving of Plug & Play PV Systems as a framework, with a variety of components compatible with the Plug & Play PV approach, including string or microinverters, conventional modules or emerging lightweight modules. The framework enables a broad group of manufacturers to participate in taking Plug & Play PV Systems to market, and increases the market size for such systems. Key aspects of the development effort centered on the system hardware and associated engineering work, the development of a Plug & Play PV Server to enable the electronic permitting, inspection and interconnection process, understanding the details of code compliance and, on occasion, supporting applications for modifications to the code to allow lightweight modules, for example. We have published a number of papers on our testing and assessment of novel technologies (e.g., adhered lightweight modules) and on the electronic architecture.

  13. Pathogenesis of arenavirus hemorrhagic fevers.

    Science.gov (United States)

    Moraz, Marie-Laurence; Kunz, Stefan

    2011-01-01

    Viral hemorrhagic fevers (VHFs) caused by arenaviruses belong to the most devastating emerging human diseases and represent serious public health problems. Arenavirus VHFs in humans are acute diseases characterized by fever and, in severe cases, different degrees of hemorrhages associated with a shock syndrome in the terminal stage. Over the past years, much has been learned about the pathogenesis of arenaviruses at the cellular level, in particular their ability to subvert the host cell's innate antiviral defenses. Clinical studies and novel animal models have provided important new information about the interaction of hemorrhagic arenaviruses with the host's adaptive immune system, in particular virus-induced immunosuppression, and have provided the first hints towards an understanding of the terminal hemorrhagic shock syndrome. The scope of this article is to review our current knowledge on arenavirus VHF pathogenesis with an emphasis on recent developments.

  14. Nutritional rickets: pathogenesis and prevention.

    Science.gov (United States)

    Pettifor, John M

    2013-06-01

    Nutritional rickets remains a public health concern in many areas of the world despite cheap and effective means of preventing the disease. The roles of vitamin D deficiency, low dietary calcium intakes and the interrelationships between the two in the pathogenesis of the disease are discussed. It is now recognized that vitamin D deficiency in the pregnant and lactating mother predisposes to the development of rickets in the breastfed infant, and that cultural and social factors are important in the pathogenesis of the disease during the adolescent growth spurt. Prevention of rickets is dependent on the awareness of the medical profession and the general public of the need to ensure adequate intakes of vitamin D in at-risk populations, and of the importance of increasing dietary intakes of calcium using locally available and inexpensive foods in communities in which dietary calcium deficiency rickets is prevalent.

  15. Vitiligo: symptoms, pathogenesis and treatment.

    Science.gov (United States)

    Ghafourian, A; Ghafourian, S; Sadeghifard, N; Mohebi, R; Shokoohini, Y; Nezamoleslami, S; Hamat, R A

    2014-01-01

    Vitiligo is an acquired cutaneous disorder of pigmentation, with an incidence of 0.5% to 2% worldwide. There are three major hypotheses for the pathogenesis of vitiligo that are not exclusive of each other: biochemical/cytotoxic, neural and autoimmune. Recent data provide strong evidence supporting an autoimmune pathogenesis of vitiligo. As vitiligo can have a major effect on quality of life, treatment can be considered and should preferably begin early when then disease is active. Current treatment modalities are directed towards stopping progression of the disease and achieving repigmentation. Therapies include corticosteroids, topical immunomodulators, photo(chemo)therapy, surgery, combination therapies and depigmentation of normally pigmented skin. It seems that traditional Chinese medicine could be more effective than the current treatment for vitligo.

  16. Molecular pathogenesis of Parkinson disease.

    Science.gov (United States)

    Eriksen, Jason L; Wszolek, Zbigniew; Petrucelli, Leonard

    2005-03-01

    Parkinson disease (PD), the most common neurodegenerative movement disorder, is characterized by an extensive and progressive loss of dopaminergic neurons in the substantia nigra pars compacta. One of the pathological hallmarks of PD is the presence of Lewy bodies, intracellular inclusions of aggregated alpha-synuclein. Although the cause and pathogenesis of selective loss of dopamine neurons and the accumulation of alpha-synuclein in PD remain elusive, growing lines of evidence from environmental risk factors and early-onset genetics point to a convergence between energy metabolism and the disposal of damaged proteins in the development of PD. These findings suggest that impairments in mitochondrial and ubiquitin-proteasome system function can significantly contribute to the pathogenesis of PD. This review will summarize recent insights gained from genetic and environmental studies of PD that underscore this association.

  17. The complete mitochondrial genome of the citrus red mite Panonychus citri (Acari: Tetranychidae): high genome rearrangement and extremely truncated tRNAs.

    Science.gov (United States)

    Yuan, Ming-Long; Wei, Dan-Dan; Wang, Bao-Jun; Dou, Wei; Wang, Jin-Jun

    2010-10-23

    The family Tetranychidae (Chelicerata: Acari) includes ~1200 species, many of which are of agronomic importance. To date, mitochondrial genomes of only two Tetranychidae species have been sequenced, and it has been found that these two mitochondrial genomes are characterized by many unusual features in genome organization and structure such as gene order and nucleotide frequency. The scarcity of available sequence data has greatly impeded evolutionary studies in Acari (mites and ticks). Information on Tetranychidae mitochondrial genomes is quite important for phylogenetic evaluation and population genetics, as well as the molecular evolution of functional genes such as acaricide-resistance genes. In this study, we sequenced the complete mitochondrial genome of Panonychus citri (Family Tetranychidae), a worldwide citrus pest, and provide a comparison to other Acari. The mitochondrial genome of P. citri is a typical circular molecule of 13,077 bp, and contains the complete set of 37 genes that are usually found in metazoans. This is the smallest mitochondrial genome within all sequenced Acari and other Chelicerata, primarily due to the significant size reduction of protein coding genes (PCGs), a large rRNA gene, and the A + T-rich region. The mitochondrial gene order for P. citri is the same as those for P. ulmi and Tetranychus urticae, but distinctly different from other Acari by a series of gene translocations and/or inversions. The majority of the P. citri mitochondrial genome has a high A + T content (85.28%), which is also reflected by AT-rich codons being used more frequently, but exhibits a positive GC-skew (0.03). The Acari mitochondrial nad1 exhibits a faster amino acid substitution rate than other genes, and the variation of nucleotide substitution patterns of PCGs is significantly correlated with the G + C content. Most tRNA genes of P. citri are extremely truncated and atypical (44-65, 54.1 ± 4.1 bp), lacking either the T- or D-arm, as found in P. ulmi

  18. The complete mitochondrial genome of the citrus red mite Panonychus citri (Acari: Tetranychidae: high genome rearrangement and extremely truncated tRNAs

    Directory of Open Access Journals (Sweden)

    Dou Wei

    2010-10-01

    Full Text Available Abstract Background The family Tetranychidae (Chelicerata: Acari includes ~1200 species, many of which are of agronomic importance. To date, mitochondrial genomes of only two Tetranychidae species have been sequenced, and it has been found that these two mitochondrial genomes are characterized by many unusual features in genome organization and structure such as gene order and nucleotide frequency. The scarcity of available sequence data has greatly impeded evolutionary studies in Acari (mites and ticks. Information on Tetranychidae mitochondrial genomes is quite important for phylogenetic evaluation and population genetics, as well as the molecular evolution of functional genes such as acaricide-resistance genes. In this study, we sequenced the complete mitochondrial genome of Panonychus citri (Family Tetranychidae, a worldwide citrus pest, and provide a comparison to other Acari. Results The mitochondrial genome of P. citri is a typical circular molecule of 13,077 bp, and contains the complete set of 37 genes that are usually found in metazoans. This is the smallest mitochondrial genome within all sequenced Acari and other Chelicerata, primarily due to the significant size reduction of protein coding genes (PCGs, a large rRNA gene, and the A + T-rich region. The mitochondrial gene order for P. citri is the same as those for P. ulmi and Tetranychus urticae, but distinctly different from other Acari by a series of gene translocations and/or inversions. The majority of the P. citri mitochondrial genome has a high A + T content (85.28%, which is also reflected by AT-rich codons being used more frequently, but exhibits a positive GC-skew (0.03. The Acari mitochondrial nad1 exhibits a faster amino acid substitution rate than other genes, and the variation of nucleotide substitution patterns of PCGs is significantly correlated with the G + C content. Most tRNA genes of P. citri are extremely truncated and atypical (44-65, 54.1 ± 4.1 bp, lacking

  19. PV-BUK: Operating and maintenance costs of photovoltaic installations; PV-BUK - Betriebs- und Unterhaltskosten von PV-Anlagen - Schlussbericht

    Energy Technology Data Exchange (ETDEWEB)

    Stettler, S.; Toggweiler, P. [Enecolo AG, Moenchaltorf (Switzerland); Ruoss, D.; Schudel, P. [Envision, Lucerne (Switzerland); Kottmann, A.; Steinle, F. [BE Netz AG, Lucerne (Switzerland)

    2008-03-15

    This final report elaborated for the Swiss Federal Office of Energy (SFOE) takes a look at the results of a project carried out to determine the costs for facility management, to estimate future cost development and to propose activities for the further reduction of the operation and maintenance costs of photovoltaic systems. Information on the cost situation was collected by literature study, as well as in interviews and surveys with photovoltaic (PV) experts and the owners of PV installations. The discussion of the results at a workshop with about 20 Swiss PV experts is noted. The results are presented and discussed. These show that operating costs per kWh decrease with the size of the PV system. Figures are quoted. The major part of the costs are quoted as being those for spare parts, especially for the inverter. The authors are of the opinion that, in future, costs for facility management will further decrease, as they are partly linked to capital and insurance costs. Potential for optimisation is said to exist in several areas of facility management such as, for example, in system monitoring and fast reaction in the case of malfunctions.

  20. [Pathogenesis of invasive fungal infections].

    Science.gov (United States)

    Garcia-Vidal, Carolina; Carratalà, Jordi

    2012-03-01

    Invasive fungal infections remain a life-threatening disease. The development of invasive fungal disease is dependent on multiple factors, such us colonization and efficient host immune response. We aimed to review the pathogenesis of invasive fungal infections, in particular, those caused by Candida and Aspergillus. For this we propose, to describe the fungal characteristics, to detail the host defence mechanisms against fungus and to analyse the host risk factors for invasive fungal infection.

  1. Pathogenesis of listeriosis during pregnancy.

    Science.gov (United States)

    Poulsen, Keith P; Czuprynski, Charles J

    2013-06-01

    Listeria monocytogenes causes several clinical manifestations in humans and domestic animals. This bacterium is a saprophyte in soil and ensiled feeds, which are sources of infection for food producing animals (i.e. ruminants). The most common route of infection for people is via ingestion of contaminated ready-to-eat food products such as produce, soft cheeses and deli meats. In the United States, L. monocytogenes causes relatively few cases of clinical disease compared to other food-borne pathogens. However, clinical listeriosis is associated with high mortality, especially in immunocompromised patients, pregnant women, neonates, and the elderly. Listeria is an intracellular pathogen, which has been widely used in basic research to elucidate mechanisms of molecular pathogenesis and protective cell-mediated immunity. Despite the sizeable knowledge on L. monocytogenes pathogenesis, key points regarding listeriosis during pregnancy and the perinatal period remain unknown. This review summarizes listeriosis in humans and domestic animals during pregnancy, and animal models used to study the pathogenesis and immune response to L. monocytogenes infection during these periods.

  2. Epigenetics and Colorectal Cancer Pathogenesis

    Energy Technology Data Exchange (ETDEWEB)

    Bardhan, Kankana; Liu, Kebin, E-mail: Kliu@gru.edu [Department of Biochemistry and Molecular Biology, Medical College of Georgia, and Cancer Center, Georgia Regents University, Augusta, GA 30912 (United States)

    2013-06-05

    Colorectal cancer (CRC) develops through a multistage process that results from the progressive accumulation of genetic mutations, and frequently as a result of mutations in the Wnt signaling pathway. However, it has become evident over the past two decades that epigenetic alterations of the chromatin, particularly the chromatin components in the promoter regions of tumor suppressors and oncogenes, play key roles in CRC pathogenesis. Epigenetic regulation is organized at multiple levels, involving primarily DNA methylation and selective histone modifications in cancer cells. Assessment of the CRC epigenome has revealed that virtually all CRCs have aberrantly methylated genes and that the average CRC methylome has thousands of abnormally methylated genes. Although relatively less is known about the patterns of specific histone modifications in CRC, selective histone modifications and resultant chromatin conformation have been shown to act, in concert with DNA methylation, to regulate gene expression to mediate CRC pathogenesis. Moreover, it is now clear that not only DNA methylation but also histone modifications are reversible processes. The increased understanding of epigenetic regulation of gene expression in the context of CRC pathogenesis has led to development of epigenetic biomarkers for CRC diagnosis and epigenetic drugs for CRC therapy.

  3. Structural features of PhoX, one of the phosphate-binding proteins from Pho regulon of Xanthomonas citri

    Science.gov (United States)

    Pegos, Vanessa R.; Santos, Rodrigo M. L.; Medrano, Francisco J.

    2017-01-01

    In Escherichia coli, the ATP-Binding Cassette transporter for phosphate is encoded by the pstSCAB operon. PstS is the periplasmic component responsible for affinity and specificity of the system and has also been related to a regulatory role and chemotaxis during depletion of phosphate. Xanthomonas citri has two phosphate-binding proteins: PstS and PhoX, which are differentially expressed under phosphate limitation. In this work, we focused on PhoX characterization and comparison with PstS. The PhoX three-dimensional structure was solved in a closed conformation with a phosphate engulfed in the binding site pocket between two domains. Comparison between PhoX and PstS revealed that they originated from gene duplication, but despite their similarities they show significant differences in the region that interacts with the permeases. PMID:28542513

  4. Lifetime Evaluation of PV Inverters considering Panel Degradation Rates and Installation Sites

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso

    2017-01-01

    The PV inverter lifetime is affected by the installed sites related to different solar irradiance and ambient temperature profiles. In fact, the installation site also affects the PV panel degradation rate, and thus the long-term power production. Prior-art lifetime analysis in PV inverters has...... not yet investigated the impact of panel degradation. This paper thus evaluates the lifetime of PV inverters considering panel degradation rates and installation sites. Evaluations have been carried out on PV systems installed in Denmark and Arizona. The results reveal that the PV panel degradation rate...... has a considerable impact on the PV inverter lifetime, especially in the hot climate (e.g., Arizona), where the panel degrades at a faster rate. In that case, the PV inverter lifetime estimation can be deviated by 54%, if the impact of PV panel degradation is not taken into account....

  5. Policies and opportunities for grid parity of PV in the Netherlands

    Energy Technology Data Exchange (ETDEWEB)

    Lako, P.; Beurskens, L.W.M. [ECN Policy Studies, Petten (Netherlands)

    2012-01-15

    In 2010, ECN Policy Studies has provided information on the development of solar PV in the Netherlands to GlobalData, India. Based on this information request, the present note on policies and opportunities for grid parity of PV has been drafted. Recently, subsidies for solar PV in the Netherlands have shown a pattern of a roller-coaster that is typical for PV financing in a number of EU countries. Stop-and-go policies for solar PV may have multiple causes. It may be difficult to determine the right feed-in tariffs for PV; or governments may be reluctant to provide sufficient funding for a relatively expensive renewable electricity source like PV. This note sheds light on the current state of affairs and policies for PV in the Netherlands, and on several private initiatives aimed at reaching grid parity for PV which is installed by households.

  6. Methods for the Optimal Design of Grid-Connected PV Inverters

    DEFF Research Database (Denmark)

    Koutroulis, Eftichios; Blaabjerg, Frede

    2011-01-01

    and the efficient processing of this power by the DC/AC inverter. In this paper two new methods are presented for the optimal design of a PV inverter power section, output filter and MPPT control strategy. The influences of the electric grid regulations and standards as well as the PV array operational......The DC/AC inverters are used in grid-connected PV energy production systems as the power processing interface between the PV energy source and the electric grid. The energy injected into the electric grid by the PV installation depends on the amount of power extracted from the PV power source...... characteristics on the design of grid-connected PV inverters have been considered. The proposed methods have been applied for the optimal design of PV inverters installed at various sites in Europe. The simulation results verify that the proposed optimization techniques enable the maximization of the PV energy...

  7. Performance of a PV module augmented by a plane reflector

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, G. E; Hussein, H. M. S; Mohamad, M. A [Dokki, Giza (Egypt)

    2000-07-01

    This paper presents a comparative experimental study on the performance of a PV module augmented by a south facing titled plane reflector and another identical one without reflector. The tilt angles of the two PV modules and reflector overhang are selected to be according to a previous theoretical study by the authors. The reflector tilt angle has been changed once a month so that the reflected beams from the plane reflector cover the total surface area of the PV module all days of every month during the high solar radiation period (i.e. three hours before and after solar noon). The study has been carried out on the two PV modules for a complete year under the actual atmospheric conditions of Cairo, Egypt. The measuring system used in the study comprises a data acquisition system, a computer, an electronic load and weather station. The experimental results indicate that the plane reflector enhances the yearly output energy of the PV module y about 22%. [Spanish] Este articulo presenta un estudio comparativo experimental sobre el rendimiento de un modulo de PV aumentado por un reflector plano inclinado mirando hacia el sur y otro identico sin reflector. Los angulos de inclinacion de los dos modulos y el reflector sobresaliente se seleccionan para que esten de acuerdo con un estudio teorico previo hecho por los autores. El angulo de inclinacion del reflector se cambio una vez al mes de manera que los rayos reflejados por el reflector plano cubrieran el area total de la superficie del modulo de PV todos los dias de cada mes durante el periodo de radiacion alto (o sea tres horas antes y despues del medio dia solar). El estudio ha sido llevado a cabo en dos modulos de PV durante un ano completo bajo condiciones atmosfericas reales de El Cairo, Egipto. El sistema de medicion usado en el estudio comprende un sistema de adquisicion de datos, una computadora, una memoria electronica y una estacion climatologica. Los resultados experimentales indican que el reflector plano

  8. PV Reconfiguration Systems: a Technical and Economic Study

    Directory of Open Access Journals (Sweden)

    Caruso M.

    2017-03-01

    Full Text Available Dynamical electrical array reconfiguration strategies for grid-connected PV systems have been proposed as solution to improve energy production due to the mismatch effect of PV plants during partial shading conditions. Strategies are based on the use of dynamic connections between PV panels given by the employment of switches that allow for each panel the series, parallel or exclusion connections, physically changing the electrical connections between the related PV modules, consequentially modifying the layout of the plant. Usually the cost of the dynamic matrix is not taken into account. This novel work evaluates the economic advantages obtained by the use of reconfiguration strategies in PV systems, by taking into consideration the price of energy due to incentives in different European and non-European countries and correlates it with the employment of two types of reconfigurators, with different internal structures. For each of the incentives proposed by the different Countries, the main strength and weakness points of the possible investment are highlighted and critically analyzed. From this analysis, it can be stated that the adoption of reconfiguration systems, in certain cases, can be a very convenient solution.

  9. Solar cell junction temperature measurement of PV module

    KAUST Repository

    Huang, B.J.

    2011-02-01

    The present study develops a simple non-destructive method to measure the solar cell junction temperature of PV module. The PV module was put in the environmental chamber with precise temperature control to keep the solar PV module as well as the cell junction in thermal equilibrium with the chamber. The open-circuit voltage of PV module Voc is then measured using a short pulse of solar irradiation provided by a solar simulator. Repeating the measurements at different environment temperature (40-80°C) and solar irradiation S (200-1000W/m2), the correlation between the open-circuit voltage Voc, the junction temperature Tj, and solar irradiation S is derived.The fundamental correlation of the PV module is utilized for on-site monitoring of solar cell junction temperature using the measured Voc and S at a short time instant with open circuit. The junction temperature Tj is then determined using the measured S and Voc through the fundamental correlation. The outdoor test results show that the junction temperature measured using the present method, Tjo, is more accurate. The maximum error using the average surface temperature Tave as the junction temperature is 4.8 °C underestimation; while the maximum error using the present method is 1.3 °C underestimation. © 2010 Elsevier Ltd.

  10. Thermal performances of vertical hybrid PV/T air collector

    Science.gov (United States)

    Tabet, I.; Touafek, K.; Bellel, N.; Khelifa, A.

    2016-11-01

    In this work, numerical analyses and the experimental validation of the thermal behavior of a vertical photovoltaic thermal air collector are investigated. The thermal model is developed using the energy balance equations of the PV/T air collector. Experimental tests are conducted to validate our mathematical model. The tests are performed in the southern Algerian region (Ghardaïa) under clear sky conditions. The prototype of the PV/T air collector is vertically erected and south oriented. The absorber upper plate temperature, glass cover temperature, air temperature in the inlet and outlet of the collector, ambient temperature, wind speed, and solar radiation are measured. The efficiency of the collector increases with increase in mass flow of air, but the increase in mass flow of air reduces the temperature of the system. The increase in efficiency of the PV/T air collector is due to the increase in the number of fins added. In the experiments, the air temperature difference between the inlet and the outlet of the PV/T air collector reaches 10 ° C on November 21, 2014, the interval time is between 10:00 and 14:00, and the temperature of the upper plate reaches 45 ° C at noon. The mathematical model describing the dynamic behavior of the typical PV/T air collector is evaluated by calculating the root mean square error and mean absolute percentage error. A good agreement between the experiment and the simulation results is obtained.

  11. Design of direct solar PV driven air conditioner

    KAUST Repository

    Huang, Bin-Juine

    2015-12-05

    © 2015 Elsevier Ltd. Solar air conditioning system directly driven by stand-alone solar PV is studied. The air conditioning system will suffer from loss of power if the solar PV power generation is not high enough. It requires a proper system design to match the power consumption of air conditioning system with a proper PV size. Six solar air conditioners with different sizes of PV panel and air conditioners were built and tested outdoors to experimentally investigate the running probabilities of air conditioning at various solar irradiations. It is shown that the instantaneous operation probability (OPB) and the runtime fraction (RF) of the air conditioner are mainly affected by the design parameter rpL (ratio of maximum PV power to load power). The measured OPB is found to be greater than 0.98 at instantaneous solar irradiation IT > 600 W m-2 if rpL > 1.71 RF approaches 1.0 (the air conditioner is run in 100% with solar power) at daily-total solar radiation higher than 13 MJ m-2 day-1, if rpL > 3.

  12. ESTIMATION OF PV MODULE SURFACE TEMPERATURE USING ARTIFICIAL NEURAL NETWORKS

    Directory of Open Access Journals (Sweden)

    Can Coskun

    2016-12-01

    Full Text Available This study aimed to use the artificial neural network (ANN method to estimate the surface temperature of a photovoltaic (PV panel. Using the experimentally obtained PV data, the accuracy of the ANN model was evaluated. To train the artificial neural network (ANN, outer temperature solar radiation and wind speed values were inputs and surface temperature was an output. The ANN was used to estimate PV panel surface temperature. Using the Levenberg-Marquardt (LM algorithm the feed forward artificial neural network was trained. Two back propagation type ANN algorithms were used and their performance was compared with the estimate from the LM algorithm. To train the artificial neural network, experimental data were used for two thirds with the remaining third used for testing. Additionally scaled conjugate gradient (SCG back propagation and resilient back propagation (RB type ANN algorithms were used for comparison with the LM algorithm. The performances of these three types of artificial neural network were compared and mean error rates of between 0.005962 and 0.012177% were obtained. The best estimate was produced by the LM algorithm. Estimation of PV surface temperature with artificial neural networks provides better results than conventional correlation methods. This study showed that artificial neural networks may be effectively used to estimate PV surface temperature.

  13. Planar holographic spectrum-splitting PV module design

    Science.gov (United States)

    Gordon, Michael; Zhang, Deming; Vorndran, Shelby; Russo, Juan M.; Luscombe, Christine K.; Shaheen, Sean E.; Kostuk, Raymond K.

    2012-10-01

    A design is presented for a planar spectrum-splitting photovoltaic (PV) module using Holographic Optical Elements (HOEs). A repeating array of HOEs diffracts portions of the solar spectrum onto different PV materials arranged in alternating strips. Several combinations of candidate PV materials are explored, and theoretical power conversion efficiency is quantified and compared for each case. The holograms are recorded in dichromated gelatin (DCG) film, an inexpensive material which is easily encapsulated directly into the panel. If desired, the holograms can focus the light to achieve concentration. The side-by-side split spectrum layout has advantages compared to a stacked tandem cell approach: since the cells are electrically isolated, current matching constraints are eliminated. Combinations of dissimilar types of cells are also possible: including crystalline, thin film, and organic PV cells. Configurations which yield significant efficiency gain using relatively inexpensive PV materials are of particular interest. A method used to optimize HOE design to work with a different candidate cells and different package aspect ratios is developed and presented. (Aspect ratio is width of the cell strips vs. the thickness of the panel) The relationship between aspect ratio and HOE performance properties is demonstrated. These properties include diffraction efficiency, spectral selectivity, tracking alignment sensitivity, and uniformity of cell illumination.

  14. Solar Plus: A Holistic Approach to Distributed Solar PV

    Energy Technology Data Exchange (ETDEWEB)

    OShaughnessy, Eric J. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Ardani, Kristen B. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Cutler, Dylan S. [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Margolis, Robert M. [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2017-06-08

    Solar 'plus' refers to an emerging approach to distributed solar photovoltaic (PV) deployment that uses energy storage and controllable devices to optimize customer economics. The solar plus approach increases customer system value through technologies such as electric batteries, smart domestic water heaters, smart air-conditioner (AC) units, and electric vehicles We use an NREL optimization model to explore the customer-side economics of solar plus under various utility rate structures and net metering rates. We explore optimal solar plus applications in five case studies with different net metering rates and rate structures. The model deploys different configurations of PV, batteries, smart domestic water heaters, and smart AC units in response to different rate structures and customer load profiles. The results indicate that solar plus improves the customer economics of PV and may mitigate some of the negative impacts of evolving rate structures on PV economics. Solar plus may become an increasingly viable model for optimizing PV customer economics in an evolving rate environment.

  15. Solar Plus: A Holistic Approach to Distributed Solar PV

    Energy Technology Data Exchange (ETDEWEB)

    O' Shaughnessy, Eric; Ardani, Kristen; Cutler, Dylan; Margolis, Robert

    2017-05-25

    Solar 'plus' refers to an emerging approach to distributed solar photovoltaic (PV) deployment that uses energy storage and controllable devices to optimize customer economics. The solar plus approach increases customer system value through technologies such as electric batteries, smart domestic water heaters, smart air-conditioner (AC) units, and electric vehicles We use an NREL optimization model to explore the customer-side economics of solar plus under various utility rate structures and net metering rates. We explore optimal solar plus applications in five case studies with different net metering rates and rate structures. The model deploys different configurations of PV, batteries, smart domestic water heaters, and smart AC units in response to different rate structures and customer load profiles. The results indicate that solar plus improves the customer economics of PV and may mitigate some of the negative impacts of evolving rate structures on PV economics. Solar plus may become an increasingly viable model for optimizing PV customer economics in an evolving rate environment.

  16. Durability Quality Research of Concrete Containing Solar PV Cells

    Directory of Open Access Journals (Sweden)

    Chao Sao-Jeng

    2015-01-01

    Full Text Available In this article we demonstrated the study results of durability quality of concrete containing waste solar PV cells. The study used alkali activator to improve the activity of alkali-activated materials in solar PV cells so as to replace Portland cement as binder in concrete. By using sodium hydroxide as an alkali-activator, a high-pH environment is generated to excite the binding characteristics of alkali-activated materials in solar PV cells, and thus develops better durability of the mixes. The conclusions were made on effect of this cement replacement. As a result, we identified the durability for those of 16 concrete specimens predefined and made to consider various possible control factors. The conclusions also depicted that all experiments but the drying shrinkage may be helpful with the suitable use of control factors as far as concerning the recycled solar PV cells for mixing in concrete. In other words, the durability quality of concrete may be partially unacceptable of containing solar PV cells.

  17. Biocontrol ability and putative mode of action of yeasts against Geotrichum citri-aurantii in citrus fruit.

    Science.gov (United States)

    Ferraz, Luriany Pompeo; Cunha, Tatiane da; da Silva, Aline Caroline; Kupper, Katia Cristina

    2016-01-01

    Sour rot is a major postharvest disease of citrus fruit and is caused by the fungal pathogen Geotrichum citri-aurantii. A lack of chemicals certified for the control of this disease has led to the consideration of alternative methods and strategies, such as the use of yeasts as biocontrol agents. The purpose of the present study was to test the ability of yeasts isolated from leaves, flowers, fruit, and soil, and six Saccharomyces cerevisiae isolates to control citrus sour rot, to assess the mechanisms of action of the yeast isolates that were demonstrated to be effective for biocontrol, and to identify the most effective yeast isolates for the biocontrol of G. citri-aurantii. In in vivo assays, three yeast isolates (ACBL-23, ACBL-44, and ACBL-77) showed a potential for controlling sour rot in citrus fruits, both preventatively and curatively. Most of the eight yeast isolates that were assessed for a mechanism of action did not produce antifungal compounds in an amount sufficient to inhibit the growth of the pathogen. Additionally, nutrient competition among the yeast strains was not found to be a biocontrol strategy. Instead, killer activity and hydrolytic enzyme production were identified as the major mechanisms involved in the biocontrol activity of the yeasts. Isolates ACBL-23, ACBL-44, and ACBL-77, which controlled sour rot most effectively, were identified as Rhodotorula minuta, Candida azyma, and Aureobasidium pullulans, respectively. To our knowledge, this is the first report of the potential of C. azyma as a biological control agent against a postharvest pathogen and its ability to produce a killer toxin.

  18. Molecular Characterization of Vitellogenin and Its Receptor Genes from Citrus Red Mite, Panonychus citri (McGregor

    Directory of Open Access Journals (Sweden)

    Rui Zhong

    2015-03-01

    Full Text Available The production and uptake of yolk protein play an important role in the reproduction of all oviparous organisms. Vitellogenin (Vg is the precursor of vitellin (Vn, which is the major egg storage protein, and vitellogenin receptor (VgR is a necessary protein for the uptake of Vg into developing oocytes. In this paper, we characterize the full-length Vg and VgR, PcVg1 and PcVgR, respectively, of the citrus red mite Panonychus citri (McGregor. The PcVg1 cDNA is 5748 nucleotides (nt with a 5553-nt open reading frame (ORF coding for 1851 amino acids (aa, and the PcVgR is 6090 nt, containing an intact ORF of 5673 nt coding an expected protein of 1891 aa. The PcVg1 aa sequence shows a typical GLCG domain and several K/RXXR cleavage sites, and PcVgR comprises two ligand-binding domains, two epidermal growth factor (EGF-like regions containing YWTD motifs, a transmembrane domain, and a cytoplasmic domain. An analysis of the aa sequences and phylogenetics implied that both genes were genetically distinct from those of ticks and insects. The transcriptional profiles determined by real-time quantitative PCR in different developmental stages showed that both genes present the same expressional tendencies in eggs, larvae, nymphs, and adults. This suggested that the biosynthesis and uptake of PcVg occurs coordinately. The strong reproductive capacity of P. citri has been hypothesized as an important factor in its resistance; consequently, understanding the molecular mechanisms regulating Vg and VgR are fundamental for mite control.

  19. Lifetime Evaluation of Grid-Connected PV Inverters Considering Panel Degradation Rates and Installation Sites

    DEFF Research Database (Denmark)

    Sangwongwanich, Ariya; Yang, Yongheng; Sera, Dezso

    2017-01-01

    Lifetime of PV inverters is affected by the installation sites related to different solar irradiance and ambient temperature profiles (also referred to as mission profiles). In fact, the installation site also affects the degradation rate of the PV panels, and thus long-term energy production...... and reliability. Prior-art lifetime analysis in PV inverters has not yet investigated the impact of PV panel degradations. This paper thus evaluates the lifetime of PV inverters considering panel degradation rates and mission profiles. Evaluations have been carried out on PV systems installed in Denmark...

  20. Interline Photovoltaic (I-PV) power system - A novel concept of power flow control and management

    OpenAIRE

    2011-01-01

    This paper presents a new system configuration for a large-scale Photovoltaic (PV) power system with multi-line transmission/distribution networks. A PV power plant is reconfigured in a way that two adjacent power system networks/ feeders can be interconnected. The inverter modules in a PV power plant are configured such that the system is represented as a back to back inverter connected multi-line system, called as Interline-PV (I-PV) system. The proposed I-PV system then can be controlled a...

  1. Photovoltaic Module Simulink Model for a Stand-alone PV System

    Science.gov (United States)

    Qi, Chen; Ming, Zhu

    Photovoltaic(PV) Module is indispensable of a stand-alone PV system. In this paper, a one-diode equivalent circuit-based versatile simulation model in the form of masked block PV module is proposed. By the model, it is allowed to estimate behavior of PV module with respect changes on irradiance intensity, ambient temperature and parameters of the PV module. In addition, the model is capable of function of Maximum Power Point Tracking (MPPT) which can be used in the dynamic simulation of stand-alone PV systems.

  2. Comparative assessment of PV plant performance models considering climate effects

    DEFF Research Database (Denmark)

    Tina, Giuseppe; Ventura, Cristina; Sera, Dezso

    2017-01-01

    The paper investigates the effect of climate conditions on the accuracy of PV system performance models (physical and interpolation methods) which are used within a monitoring system as a reference for the power produced by a PV system to detect inefficient or faulty operating conditions....... The methodological approach is based on comparative tests of the analyzed models applied to two PV plants installed respectively in north of Denmark (Aalborg) and in the south of Italy (Agrigento). The different ambient, operating and installation conditions allow to understand how these factors impact the precision...... and effectiveness of such approaches, among these factors it is worth mentioning the different percentage of diffuse component of the yearly solar radiation on the global one. The experimental results show the effectiveness of the proposed approach. In order to have the possibility to analyze and compare...

  3. Chapter 10.3: Reliability and Durability of PV Modules

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, Sarah

    2017-01-07

    Each year the world invests tens of billions of dollars or euros in PV systems with the expectation that these systems will last approximately 25 years. Although the disciplines of reliability, quality, and service life prediction have been well established for numerous products, a full understanding of these is currently challenging for PV modules because the desired service lifetimes are decades, preventing direct verification of lifetime predictions. A number of excellent reviews can be found in the literature summarizing the types of failures that are commonly observed for PV modules. This chapter discusses key failure/degradation mechanisms selected to highlight how the kinetics of failure rates can and cannot be confidently predicted. For EVA-encapsulated modules, corrosion is observed to follow delamination, which then allows water droplets to directly contact the metallization. Extended test protocols such as Qualification Plus were created to address the known problems while standards groups update standard tests through the consensus process.

  4. DC-PLC Modem design for PV module monitoring

    Directory of Open Access Journals (Sweden)

    Seong-Duc Ma

    2016-01-01

    Full Text Available Nowadays, power line communication (PLC is a very efficient technique in cost aspect because it is communication system using power line without extra communication cables. In case of DC-PLC, it send a communication signal of the high frequency band to the monitoring system through the DC power line and is widely used for DC grid or the distributed generation system using DC source. Especially, the management system which evaluates the performance and efficiency of PV module by measuring PV power through monitoring system based on the DC-PLC has been increased. In this paper, apply the DC-PLC method for low cost PV module monitoring system and constitutes a measuring device and communication modem on a MCU. For the communication performance, we use the digital filter and apply the multi-carrier communication. The proposed DC-PLC Modem is verified through simulation and experiment.

  5. Budgeting for Solar PV Plant Operations & Maintenance: Practices and Pricing.

    Energy Technology Data Exchange (ETDEWEB)

    Enbar, Nadav [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Weng, Dean [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Klise, Geoffrey Taylor [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    With rising grid interconnections of solar photovoltaic (PV) systems, greater attention is being trained on lifecycle performance, reliability, and project economics. Expected to meet production thresholds over a 20-30 year timeframe, PV plants require a steady diet of operations and maintenance (O&M) oversight to meet contractual terms. However, industry best practices are only just beginning to emerge, and O&M budgets—given the arrangement of the solar project value chain—appear to vary widely. Based on insights from in-depth interviews and survey research, this paper presents an overview of the utility-scale PV O&M budgeting process along with guiding rationales, before detailing perspectives on current plant upkeep activities and price points largely in the U.S. It concludes by pondering potential opportunities for improving upon existing O&M budgeting approaches in ways that can benefit the industry at-large.

  6. Budgeting for Solar PV Plant Operations & Maintenance: Practices and Pricing.

    Energy Technology Data Exchange (ETDEWEB)

    Enbar, Nadav [Electric Power Research Inst. (EPRI), Palo Alto, CA (United States); Weng, Dean [Electric Power Research Inst. (EPRI), Palo Alto, CA (United States); Klise, Geoffrey Taylor [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-12-01

    With rising grid interconnections of solar photovoltaic (PV) systems, greater attention is being trained on lifecycle performance, reliability, and project economics. Expected to meet production thresholds over a 20-30 year timeframe, PV plants require a steady diet of operations and maintenance (O&M) oversight to meet contractual terms. However, industry best practices are only just beginning to emerge, and O&M budgets—given the arrangement of the solar project value chain—appear to vary widely. Based on insights from in-depth interviews and survey research, this paper presents an overview of the utility-scale PV O&M budgeting process along with guiding rationales, before detailing perspectives on current plant upkeep activities and price points largely in the U.S. It concludes by pondering potential opportunities for improving upon existing O&M budgeting approaches in ways that can benefi t the industry at-large.

  7. Z - Source Multi Level Inverter Based PV Generation System

    Directory of Open Access Journals (Sweden)

    T. Lakhmi kanth

    2014-09-01

    Full Text Available In this paper a novel technique of Z-Source multilevel Inverter based PV Generation system is implemented and simulated using MATLAB-Simulink simulation software. The Photovoltaic cells are healthier option for converting solar energy into electricity. Due to high capital cost and low efficiency PV cells have not yet been a fully smart choice for electricity users. To enhance the performance of the system, Z-Source multi level inverter can be used in place of conventional Voltage Source Inverter (VSI in Solar Power Generation System. The PV cell model is developed using circuit mathematical equations. The Z-Source multilevel inverter is modeled to realize boosted DC to AC conversion (inversion with low THD. Outcome shows that the energy conversion efficiency of ZSMLI is a lot improved as compared to conventional voltage Source Inverter (VSI. By doing FFT analysis we can know the total THD.

  8. PV Systems Installed in Marine Vessels: Technologies and Specifications

    Directory of Open Access Journals (Sweden)

    Ioannis Kobougias

    2013-01-01

    Full Text Available Considerations are held about the specificationin whichthe PV plants have to fulfill so that they can be installed on marine vessels. Initially, a brief description of the typical electrical grid of ships is presented, distinguishing the main parts, reporting the typical electrical magnitudes, and choosing the most preferable installation areas. The technical specifications,in whichthe PV plants have to be compatible with, are fully described. They are determined by the special marine environmental conditions, taking into consideration parameters like wind, humidity, shading, corrosion, and limited installation area. The work is carried out with the presentation of the most popular trends in the field of solar cell types and PV system technologies and their ability to keep up with the aforementioned specifications.

  9. Sizing aspects of a small scale grid connected PV system

    Energy Technology Data Exchange (ETDEWEB)

    Bartha, S.; Teodoreanu, D.I.; Teodoreanu, M.; Negreanu, C. [I.C.P.E.-New Energy Sources Laboratory (NESL), Bucharest (Romania); Farkas, I.; Seres, I. [Szent Istvan University, Goedoelloe (Hungary). Department of Physics and Process Control

    2008-07-01

    Photovoltaics can be used in grid connected mode in two ways: as array installed at the end use site, such as on rooftops, or as utility-scale generating stations. The present paper describes a small-scale grid connected Photovoltaic system. The paper starts with the structure and characterization of the system. The principal technical parameter data are also presented. The used monitoring parameters indicate the principal meteorological data, air temperature and solar radiation data for the location sited at Agigea, at the Black Sea and the produced energy by the PV modules. The present application is made by 1 subsystem with 1200 Wp power and with the panel inclination possibility, using different type of PV modules. The paper presents a simulation model for this system realized with commercial software packages and with a one self made Matlab model that evaluates the energy balance of the PV system. All the simulation and measurements data are presented. (orig.)

  10. Comparative analysis of old, recycled and new PV modules

    Directory of Open Access Journals (Sweden)

    Haroon Ashfaq

    2017-01-01

    Full Text Available This paper presents comparative analysis of old, recycled and new PV modules. It is possible to recycle even very old products by modern standard processes in a value-conserving manner. About 90% of the materials recovered from solar panels can be recycled into useful products. Carbon emission and energy cost are low in manufacturing recycled SPV. Modules can be manufactured with recycled materials and reinstalled in systems as a full quality product with today’s technology good for another 25–30 years. Analysis of all the models of PV module is done with the help of MATLAB. This helps in comparison and proves the effectiveness of the recycled PV module based systems.

  11. Lessons Learned from the Photovoltaic Manufacturing Technology/PV Manufacturing R&D and Thin Film PV Partnership Projects

    Energy Technology Data Exchange (ETDEWEB)

    Margolis, R.; Mitchell, R.; Zweibel, K.

    2006-09-01

    As the U.S. Department of Energy's (DOE's) Solar Energy Technologies Program initiates new cost-shared solar energy R&D under the Solar America Initiative (SAI), it is useful to analyze the experience gained from cost-shared R&D projects that have been funded through the program to date. This report summarizes lessons learned from two DOE-sponsored photovoltaic (PV) projects: the Photovoltaic Manufacturing Technology/PV Manufacturing R&D (PVMaT/PVMR&D) project and the Thin-Film PV Partnership project. During the past 10-15 years, these two projects have invested roughly $330 million of government resources in cost-shared R&D and leveraged another $190 million in private-sector PV R&D investments. Following a description of key findings and brief descriptions of the PVMaT/PVMR&D and Thin-Film PV Partnership projects, this report presents lessons learned from the projects.

  12. Pseudomonas cannabina pv. cannabina pv. nov., and Pseudomonas cannabina pv. alisalensis (Cintas Koike and Bull, 2000) comb. nov., are members of the emended species Pseudomonas cannabina (ex Sutic & Dowson 1959) Gardan, Shafik, Belouin, Brosch, Grimont & Grimont 1999.

    Science.gov (United States)

    Bull, Carolee T; Manceau, Charles; Lydon, John; Kong, Hyesuk; Vinatzer, Boris A; Fischer-Le Saux, Marion

    2010-04-01

    Sequence similarity in the 16S rDNA gene confirmed that crucifer pathogen Pseudomonas syringae pv. alisalensis belongs to P. syringae sensu lato. In reciprocal DNA/DNA hybridization experiments, DNA relatedness was high (69-100%) between P. syringae pv. alisalensis strains and the type strain of P. cannabina (genomospecies 9). In contrast, DNA relatedness was low (below 48%) between P. syringae pv. alisalensis and reference strains from the remaining genomospecies of P. syringae including the type strain of P. syringae and reference strain of genomospecies 3 (P. syringae pv. tomato) although the well-known crucifer pathogen, P. syringae pv. maculicola, also belongs to genomospecies 3. Additional evidence that P. syringae pv. alisalensis belongs to P. cannabina was sequence similarity in five gene fragments used in multilocus sequence typing, as well as similar rep-PCR patterns when using the BOX-A1R primers. The description of P. cannabina has been emended to include P. syringae pv. alisalensis. Host range testing demonstrated that P. syringae pv. alisalensis strains, originally isolated from broccoli, broccoli raab or arugula, were not pathogenic on Cannabis sativa (family Cannabinaceae). Additionally, P. cannabina strains, originally isolated from the C. sativa were not pathogenic on broccoli raab or oat while P. syringae pv. alisalensis strains were pathogenic on these hosts. Distinct host ranges for these two groups indicate that P. cannabina emend. consists of at least two distinct pathovars, P. cannabina pv. cannabina pv. nov., and P. cannabina pv. alisalensis comb. nov. Pseudomonas syringae pv. maculicola strain CFBP 1637 is a member of P. cannabina.

  13. Design, Fabrication and Certification of Advanced Modular PV Power Systems

    Science.gov (United States)

    Minyard, Glen E.; Lambarski, Timothy J.

    1997-02-01

    The Design, Fabrication and Certification of Advanced Modular PV Power Systems contract is a Photovoltaic Manufacturing Technology (PVMaT) cost-shared contract under Phase 4A1 for Product Driven Systems and Component Technologies. Phase 4A1 has the goals to improve the cost-effectiveness and manufacturing efficiency of PV end-products, optimize manufacturing and packaging methods, and generally improve balance-of-system performance, integration and manufacturing. This contract has the specific goal to reduce the installed PV system life cycle costs to the customer with the ultimate goal of increasing PV system marketability and customer acceptance. The specific objectives of the project are to develop certified, standardized, modular, pre-engineered products lines of our main stand-alone systems, the Modular Autonomous PV Power Supply (MAPPS) and PV-Generator Hybrid System (Photogenset). To date, we have designed a 200 W MAPPS and a 1 kW Photogenset and are in the process of having the MAPPS certified by Underwriters Laboratories (UL Listed) and approved for hazardous locations by Factory Mutual (FM). We have also developed a manufacturing plan for product line expansion for the MAPPS. The Photogenset will be fabricated in February 1997 and will also be UL Listed. Functionality testing will be performed at NREL and Sandia with the intentions of providing verification of performance and reliability and of developing test-based performance specifications. In addition to an expansion on the goals, objectives and status of the project, specific accomplishments and benefits are also presented in this paper.

  14. Time series power flow analysis for distribution connected PV generation.

    Energy Technology Data Exchange (ETDEWEB)

    Broderick, Robert Joseph; Quiroz, Jimmy Edward; Ellis, Abraham; Reno, Matthew J.; Smith, Jeff; Dugan, Roger

    2013-01-01

    Distributed photovoltaic (PV) projects must go through an interconnection study process before connecting to the distribution grid. These studies are intended to identify the likely impacts and mitigation alternatives. In the majority of the cases, system impacts can be ruled out or mitigation can be identified without an involved study, through a screening process or a simple supplemental review study. For some proposed projects, expensive and time-consuming interconnection studies are required. The challenges to performing the studies are twofold. First, every study scenario is potentially unique, as the studies are often highly specific to the amount of PV generation capacity that varies greatly from feeder to feeder and is often unevenly distributed along the same feeder. This can cause location-specific impacts and mitigations. The second challenge is the inherent variability in PV power output which can interact with feeder operation in complex ways, by affecting the operation of voltage regulation and protection devices. The typical simulation tools and methods in use today for distribution system planning are often not adequate to accurately assess these potential impacts. This report demonstrates how quasi-static time series (QSTS) simulation and high time-resolution data can be used to assess the potential impacts in a more comprehensive manner. The QSTS simulations are applied to a set of sample feeders with high PV deployment to illustrate the usefulness of the approach. The report describes methods that can help determine how PV affects distribution system operations. The simulation results are focused on enhancing the understanding of the underlying technical issues. The examples also highlight the steps needed to perform QSTS simulation and describe the data needed to drive the simulations. The goal of this report is to make the methodology of time series power flow analysis readily accessible to utilities and others responsible for evaluating

  15. Modular Power Converters for PV Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ozpineci, Burak [ORNL; Tolbert, Leon M [ORNL

    2012-05-01

    This report describes technical opportunities to serve as parts of a technological roadmap for Shoals Technologies Group in power electronics for PV applications. There are many different power converter circuits that can be used for solar inverter applications. The present applications do not take advantage of the potential for using common modules. We envision that the development of a power electronics module could enable higher reliability by being durable and flexible. Modules would have fault current limiting features and detection circuits such that they can limit the current through the module from external faults and can identify and isolate internal faults such that the remaining modules can continue to operate with only minimal disturbance to the utility or customer. Development of a reliable, efficient, low-cost, power electronics module will be a key enabling technology for harnessing more power from solar panels and enable plug and play operation. Power electronics for computer power supplies, communication equipment, and transportation have all targeted reliability and modularity as key requirements and have begun concerted efforts to replace monolithic components with collections of common smart modules. This is happening on several levels including (1) device level with intelligent control, (2) functional module level, and (3) system module. This same effort is needed in power electronics for solar applications. Development of modular units will result in standard power electronic converters that will have a lower installed and operating cost for the overall system. These units will lead to increased adaptability and flexibility of solar inverters. Incorporating autonomous fault current limiting and reconfiguration capabilities into the modules and having redundant modules will lead to a durable converter that can withstand the rigors of solar power generation for more than 30 years. Our vision for the technology roadmap is that there is no need

  16. Modular Power Converters for PV Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ozpineci, Burak [ORNL; Tolbert, Leon M [ORNL

    2012-05-01

    This report describes technical opportunities to serve as parts of a technological roadmap for Shoals Technologies Group in power electronics for PV applications. There are many different power converter circuits that can be used for solar inverter applications. The present applications do not take advantage of the potential for using common modules. We envision that the development of a power electronics module could enable higher reliability by being durable and flexible. Modules would have fault current limiting features and detection circuits such that they can limit the current through the module from external faults and can identify and isolate internal faults such that the remaining modules can continue to operate with only minimal disturbance to the utility or customer. Development of a reliable, efficient, low-cost, power electronics module will be a key enabling technology for harnessing more power from solar panels and enable plug and play operation. Power electronics for computer power supplies, communication equipment, and transportation have all targeted reliability and modularity as key requirements and have begun concerted efforts to replace monolithic components with collections of common smart modules. This is happening on several levels including (1) device level with intelligent control, (2) functional module level, and (3) system module. This same effort is needed in power electronics for solar applications. Development of modular units will result in standard power electronic converters that will have a lower installed and operating cost for the overall system. These units will lead to increased adaptability and flexibility of solar inverters. Incorporating autonomous fault current limiting and reconfiguration capabilities into the modules and having redundant modules will lead to a durable converter that can withstand the rigors of solar power generation for more than 30 years. Our vision for the technology roadmap is that there is no need

  17. Progress on pathogenesis of pterygium

    Directory of Open Access Journals (Sweden)

    Li Peng

    2013-10-01

    Full Text Available Pterygium is one of the common ocular surface diseases, characterized by local subconjunctival fibrovascular proliferation invading the cornea, not only influences facial beauty, but affects visual acuity and causes ocular dyskinesia. Surgical removal is the main treatment option. However, the recurrence rate is high(20%-40%. Many explanations are put forward by scientists, but the mechanism of pterygium still remains unclear. It is of great importance to study the pathogenesis of pterygium so as to prevent its occurrence and development. In this paper, we make a review about the domestic and international studies of the inhibition of apoptosis, matrix metalloproteinase, oxidative stress and immunity in pterygium.

  18. Biology and pathogenesis of Acanthamoeba

    Directory of Open Access Journals (Sweden)

    Siddiqui Ruqaiyyah

    2012-01-01

    Full Text Available Abstract Acanthamoeba is a free-living protist pathogen, capable of causing a blinding keratitis and fatal granulomatous encephalitis. The factors that contribute to Acanthamoeba infections include parasite biology, genetic diversity, environmental spread and host susceptibility, and are highlighted together with potential therapeutic and preventative measures. The use of Acanthamoeba in the study of cellular differentiation mechanisms, motility and phagocytosis, bacterial pathogenesis and evolutionary processes makes it an attractive model organism. There is a significant emphasis on Acanthamoeba as a Trojan horse of other microbes including viral, bacterial, protists and yeast pathogens.

  19. Psoriatic arthritis: genetics and pathogenesis

    Directory of Open Access Journals (Sweden)

    A. Mathieu

    2012-06-01

    Full Text Available Psoriatic arthritis is a complex disease affecting primarily peripheral and axial joints and entheses together with the skin. The pathogenesis is characterized by a genetic background and by inflammatory mechanisms which may be triggered by environmental factors. Several susceptibility genes have been investigated; they include HLA genes, genes within the HLA region and genes outside the HLA region. T cells, including the recently described subset Th17, are thought to play an important role in the acute and chronic phases of the disease. Some of these findings allowed novel therapeutic interventions or opened new promising approaches in treatment. The most relevant data of the literature are summarized and discussed.

  20. PV domestic field trial. Third annual technical report

    Energy Technology Data Exchange (ETDEWEB)

    Crick, F.; Davies, N.; Munzinger, M.; Pearsall, N.; Martin, C.

    2004-07-01

    This report summaries the results of a field trials investigating the design, construction and operation of photovoltaic (PV) systems installed during 2003 to provide information for utilities, building developers and those involved in PV installations and operations. Topics examined include the appearance of the systems, their architectural integration, the different fixing methods, the cost effectiveness of the systems, problems encountered, and monitoring activities. Key issues discussed include communication and co-ordination between interested bodies, siting and location, and good practice. Details are given of monitoring inspection visits, and performance analysis.