Science.gov

Sample records for pathogens highly mobile

  1. High mobility group (HMG-box) genes in the honeybee fungal pathogen Ascosphaera apis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genome of the honey bee fungal pathogen, Ascosphaera apis (Maassen), encodes three putative high mobility group (HMG-box) transcription factors. The predicted proteins (MAT1-2, STE11 and HTF), each of which contain a single strongly conserved HMG-box, exhibit high similarity to mating type prote...

  2. Human mobility and the worldwide impact of intentional localized highly pathogenic virus release

    PubMed Central

    Gonçalves, Bruno; Balcan, Duygu; Vespignani, Alessandro

    2013-01-01

    The threat of bioterrorism and the possibility of accidental release have spawned a growth of interest in modeling the course of the release of a highly pathogenic agent. Studies focused on strategies to contain local outbreaks after their detection show that timely interventions with vaccination and contact tracing are able to halt transmission. However, such studies do not consider the effects of human mobility patterns. Using a large-scale structured metapopulation model to simulate the global spread of smallpox after an intentional release event, we show that index cases and potential outbreaks can occur in different continents even before the detection of the pathogen release. These results have two major implications: i) intentional release of a highly pathogenic agent within a country will have global effects; ii) the release event may trigger outbreaks in countries lacking the health infrastructure necessary for effective containment. The presented study provides data with potential uses in defining contingency plans at the National and International level. PMID:23860371

  3. Human mobility and the worldwide impact of intentional localized highly pathogenic virus release.

    PubMed

    Gonçalves, Bruno; Balcan, Duygu; Vespignani, Alessandro

    2013-01-01

    The threat of bioterrorism and the possibility of accidental release have spawned a growth of interest in modeling the course of the release of a highly pathogenic agent. Studies focused on strategies to contain local outbreaks after their detection show that timely interventions with vaccination and contact tracing are able to halt transmission. However, such studies do not consider the effects of human mobility patterns. Using a large-scale structured metapopulation model to simulate the global spread of smallpox after an intentional release event, we show that index cases and potential outbreaks can occur in different continents even before the detection of the pathogen release. These results have two major implications: i) intentional release of a highly pathogenic agent within a country will have global effects; ii) the release event may trigger outbreaks in countries lacking the health infrastructure necessary for effective containment. The presented study provides data with potential uses in defining contingency plans at the National and International level. PMID:23860371

  4. Pathogenicity island mobility and gene content.

    SciTech Connect

    Williams, Kelly Porter

    2013-10-01

    Key goals towards national biosecurity include methods for analyzing pathogens, predicting their emergence, and developing countermeasures. These goals are served by studying bacterial genes that promote pathogenicity and the pathogenicity islands that mobilize them. Cyberinfrastructure promoting an island database advances this field and enables deeper bioinformatic analysis that may identify novel pathogenicity genes. New automated methods and rich visualizations were developed for identifying pathogenicity islands, based on the principle that islands occur sporadically among closely related strains. The chromosomally-ordered pan-genome organizes all genes from a clade of strains; gaps in this visualization indicate islands, and decorations of the gene matrix facilitate exploration of island gene functions. A %E2%80%9Clearned phyloblocks%E2%80%9D method was developed for automated island identification, that trains on the phylogenetic patterns of islands identified by other methods. Learned phyloblocks better defined termini of previously identified islands in multidrug-resistant Klebsiella pneumoniae ATCC BAA-2146, and found its only antibiotic resistance island.

  5. Fast detection of a protozoan pathogen, Perkinsus marinus, using AlGaN/GaN high electron mobility transistors

    NASA Astrophysics Data System (ADS)

    Wang, Yu-Lin; Chu, B. H.; Chen, K. H.; Chang, C. Y.; Lele, T. P.; Papadi, G.; Coleman, J. K.; Sheppard, B. J.; Dungen, C. F.; Pearton, S. J.; Johnson, J. W.; Rajagopal, P.; Roberts, J. C.; Piner, E. L.; Linthicum, K. J.; Ren, F.

    2009-06-01

    Antibody-functionalized, Au-gated AlGaN/GaN high electron mobility transistors (HEMTs) were used to detect Perkinsus marinus. The antibody was anchored to the gate area through immobilized thioglycolic acid. The AlGaN/GaN HEMT drain-source current showed a rapid response of less than 5 s when the infected solution was added to the antibody-immobilized surface. The sensor can be recycled with a phosphate buffered saline wash. These results clearly demonstrate the promise of field-deployable electronic biological sensors based on AlGaN/GaN HEMTs for Perkinsus marinus detection.

  6. An evaluation of the mobility of pathogen indicators, Escherichia coli and bacteriophage MS-2, in a highly weathered tropical soil under unsaturated conditions

    USGS Publications Warehouse

    Wong, T.-P.; Byappanahalli, M.; Yoneyama, B.; Ray, C.

    2008-01-01

    Laboratory column experiments were conducted to study the effects of anionic polyacrylamide (PAM) polymer and surfactant linear alkylbenzene sulfonate (LAS) on the movement of Escherichia coli and the FRNA phage MS-2. The study was designed to evaluate if PAM or PAM + LAS would enhance the mobility of human pathogens in tropical soils under unsaturated conditions. No breakthrough of phage was observed in a 10 cm column after passing 100 pore volumes of solution containing 1 ?? 108 plaque-forming units (PFU)/ml. In later experiments, after passing 10-20 pore volumes of influent containing 1 ?? 108/ml MS-2 or E. coli through 15 cm columns, the soil was sliced and the organisms eluted. Phage moved slightly deeper in the polymer-treated column than in the control column. There was no measurable difference in the movement of E. coli in either polymer-treated or control columns. The properties of the soil (high amounts of metal oxides, kaolinitic clay), unsaturated flow conditions, and relatively high ionic strengths of the leaching solution attributed to significant retention of these indicators. The impacts of PAM and LAS on the mobility of E. coli or MS-2 phage in the chosen soils were not significant. ?? IWA Publishing 2008.

  7. Chances and Limitations of Wild Bird Monitoring for the Avian Influenza Virus H5N1 — Detection of Pathogens Highly Mobile in Time and Space

    PubMed Central

    Wilking, Hendrik; Ziller, Mario; Staubach, Christoph; Globig, Anja; Harder, Timm C.; Conraths, Franz J.

    2009-01-01

    Highly pathogenic influenza virus (HPAIV) H5N1 proved to be remarkably mobile in migratory bird populations where it has led to extensive outbreaks for which the true number of affected birds usually cannot be determined. For the evaluation of avian influenza monitoring and HPAIV early warning systems, we propose a time-series analysis that includes the estimation of confidence intervals for (i) the prevalence in outbreak situations or (ii) in the apparent absence of disease in time intervals for specified regional units. For the German outbreak regions in 2006 and 2007, the upper 95% confidence limit allowed the detection of prevalences below 1% only for certain time intervals. Although more than 25,000 birds were sampled in Germany per year, the upper 95% confidence limit did not fall below 5% in the outbreak regions for most of the time. The proposed analysis can be used to monitor water bodies and high risk areas, also as part of an early-warning system. Chances for an improved targeting of the monitoring system as part of a risk-based approach are discussed with the perspective of reducing sample sizes. PMID:19680560

  8. Mobile phones: Reservoirs for the transmission of nosocomial pathogens

    PubMed Central

    Pal, Shekhar; Juyal, Deepak; Adekhandi, Shamanth; Sharma, Munesh; Prakash, Rajat; Sharma, Neelam; Rana, Amit; Parihar, Ashwin

    2015-01-01

    Background: Global burden of hospital-associated infection (HAI) is on the rise and contributes significantly to morbidity and mortality of the patients. Mobile phones are indispensible part of communication among doctors and other health care workers (HCWs) in hospitals. Hands of HCWs play an important role in transmission of HAI and mobile phones which are seldom cleaned and often touched during or after the examination of patients without hand washing can act as a reservoir for transmission of potent pathogens. This study aimed to investigate the rate of bacterial contamination of mobile phones among HCWs in our tertiary care hospital and to compare it with personal mobile phones of non-HCWs (control group). Materials and Methods: The mobile phones and dominant hands of 386 participants were sampled from four different groups, hospital doctors and staff (132), college faculty and staff (54), medical students (100) and control group (100). Informed consent and questionnaire was duly signed by all the participants. Samples were processed according to standard guidelines. Results: 316 mobile phones (81.8%) and 309 hand swab samples (80%) showed growth of bacterial pathogens. The most predominant isolates were Coagulase-negative Staphylococcus, Staphylococcus aureus, Acinetobacter species, Escherichia coli, Klebsiella pneumoniae, Pseudomonas species and Enterococcus species. Conclusion: Hundred percent contamination was found in mobile phones and hands of HCWs indicating mobile phones can be the potential source of nosocomial pathogens. Our study results suggest that use of mobile phones in health care setup should be restricted only for emergency calls. Strict adherence to infection control policies such as proper hand hygiene practices should be followed. PMID:26322292

  9. Host Mobility Drives Pathogen Competition in Spatially Structured Populations

    PubMed Central

    Poletto, Chiara; Meloni, Sandro; Colizza, Vittoria; Moreno, Yamir; Vespignani, Alessandro

    2013-01-01

    Interactions among multiple infectious agents are increasingly recognized as a fundamental issue in the understanding of key questions in public health regarding pathogen emergence, maintenance, and evolution. The full description of host-multipathogen systems is, however, challenged by the multiplicity of factors affecting the interaction dynamics and the resulting competition that may occur at different scales, from the within-host scale to the spatial structure and mobility of the host population. Here we study the dynamics of two competing pathogens in a structured host population and assess the impact of the mobility pattern of hosts on the pathogen competition. We model the spatial structure of the host population in terms of a metapopulation network and focus on two strains imported locally in the system and having the same transmission potential but different infectious periods. We find different scenarios leading to competitive success of either one of the strain or to the codominance of both strains in the system. The dominance of the strain characterized by the shorter or longer infectious period depends exclusively on the structure of the population and on the the mobility of hosts across patches. The proposed modeling framework allows the integration of other relevant epidemiological, environmental and demographic factors, opening the path to further mathematical and computational studies of the dynamics of multipathogen systems. PMID:23966843

  10. Do mobile phones of patients, companions and visitors carry multidrug-resistant hospital pathogens?

    PubMed

    Tekerekoǧlu, Mehmet Sait; Duman, Yucel; Serindağ, Ayfer; Cuǧlan, Serpil Semiha; Kaysadu, Halim; Tunc, Emine; Yakupogullari, Yusuf

    2011-06-01

    A cross-sectional study was conducted to determine bacterial colonization on the mobile phones (MPs) used by patients, patients' companions, visitors, and health care workers (HCWs). Significantly higher rates of pathogens (39.6% vs 20.6%, respectively; P = .02) were found in MPs of patients' (n = 48) versus the HCWs' (n = 12). There were also more multidrug pathogens in the patents' MPs including methicillin-resistant Staphylococcus aureus, extended-spectrum β-lactamase-producing Escherichia coli, and Klebsiella spp, high-level aminoglycoside-resistant Enterococcus spp, and carabepenem-resistant Acinetobacter baumanii. Our findings suggest that mobile phones of patients, patients' companions, and visitors represent higher risk for nosocomial pathogen colonization than those of HCWs. Specific infection control measures may be required for this threat. PMID:21624635

  11. High-mobility diamond

    NASA Astrophysics Data System (ADS)

    Landstrass, Maurice I.

    1994-04-01

    Recent improvements in the CVD diamond deposition process have made possible the fabrication of diamond photoconductive diodes with carrier mobility and lifetime exceeding the values typical of natural gemstones. One of the more surprising recent results is that the best room-temperature carrier properties have been measured on polycrystalline diamond films. The combined electron- hole mobility, as measured by transient photoconductivity at low carrier densities, is 4000 square centimeters per volt per second at electric field of 200 volts per centimeter and is comparable to that of the best single-crystal IIa natural diamonds. Carrier lifetimes measured under the same conditions are 150 picoseconds for the CVD diamond films. The collection distance within the diamond films, at the highest applied fields, is comparable to the average film grain size, indicative of little or no carrier scattering at grain boundaries. A comparison of SIMS measurements with electrical results suggest that impurity incorporation in the near grain boundary regions are responsible for controlling the carrier mobility.

  12. High mobility emissive organic semiconductor.

    PubMed

    Liu, Jie; Zhang, Hantang; Dong, Huanli; Meng, Lingqiang; Jiang, Longfeng; Jiang, Lang; Wang, Ying; Yu, Junsheng; Sun, Yanming; Hu, Wenping; Heeger, Alan J

    2015-01-01

    The integration of high charge carrier mobility and high luminescence in an organic semiconductor is challenging. However, there is need of such materials for organic light-emitting transistors and organic electrically pumped lasers. Here we show a novel organic semiconductor, 2,6-diphenylanthracene (DPA), which exhibits not only high emission with single crystal absolute florescence quantum yield of 41.2% but also high charge carrier mobility with single crystal mobility of 34 cm(2) V(-1) s(-1). Organic light-emitting diodes (OLEDs) based on DPA give pure blue emission with brightness up to 6,627 cd m(-2) and turn-on voltage of 2.8 V. 2,6-Diphenylanthracene OLED arrays are successfully driven by DPA field-effect transistor arrays, demonstrating that DPA is a high mobility emissive organic semiconductor with potential in organic optoelectronics. PMID:26620323

  13. High mobility emissive organic semiconductor

    PubMed Central

    Liu, Jie; Zhang, Hantang; Dong, Huanli; Meng, Lingqiang; Jiang, Longfeng; Jiang, Lang; Wang, Ying; Yu, Junsheng; Sun, Yanming; Hu, Wenping; Heeger, Alan J.

    2015-01-01

    The integration of high charge carrier mobility and high luminescence in an organic semiconductor is challenging. However, there is need of such materials for organic light-emitting transistors and organic electrically pumped lasers. Here we show a novel organic semiconductor, 2,6-diphenylanthracene (DPA), which exhibits not only high emission with single crystal absolute florescence quantum yield of 41.2% but also high charge carrier mobility with single crystal mobility of 34 cm2 V−1 s−1. Organic light-emitting diodes (OLEDs) based on DPA give pure blue emission with brightness up to 6,627 cd m−2 and turn-on voltage of 2.8 V. 2,6-Diphenylanthracene OLED arrays are successfully driven by DPA field-effect transistor arrays, demonstrating that DPA is a high mobility emissive organic semiconductor with potential in organic optoelectronics. PMID:26620323

  14. High mobility emissive organic semiconductor

    NASA Astrophysics Data System (ADS)

    Liu, Jie; Zhang, Hantang; Dong, Huanli; Meng, Lingqiang; Jiang, Longfeng; Jiang, Lang; Wang, Ying; Yu, Junsheng; Sun, Yanming; Hu, Wenping; Heeger, Alan J.

    2015-12-01

    The integration of high charge carrier mobility and high luminescence in an organic semiconductor is challenging. However, there is need of such materials for organic light-emitting transistors and organic electrically pumped lasers. Here we show a novel organic semiconductor, 2,6-diphenylanthracene (DPA), which exhibits not only high emission with single crystal absolute florescence quantum yield of 41.2% but also high charge carrier mobility with single crystal mobility of 34 cm2 V-1 s-1. Organic light-emitting diodes (OLEDs) based on DPA give pure blue emission with brightness up to 6,627 cd m-2 and turn-on voltage of 2.8 V. 2,6-Diphenylanthracene OLED arrays are successfully driven by DPA field-effect transistor arrays, demonstrating that DPA is a high mobility emissive organic semiconductor with potential in organic optoelectronics.

  15. 76 FR 24793 - Highly Pathogenic Avian Influenza

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-03

    ... Inspection Service 9 CFR Parts 93, 94, and 95 RIN 0579-AC36 Highly Pathogenic Avian Influenza AGENCY: Animal... products from regions where any subtype of highly pathogenic avian influenza is considered to exist. The... vaccinated for certain types of avian influenza, or that have moved through regions where any subtype...

  16. Comparative genomics reveals mobile pathogenicity chromosomes in Fusarium

    PubMed Central

    Ma, Li-Jun; van der Does, H. Charlotte; Borkovich, Katherine A.; Coleman, Jeffrey J.; Daboussi, Marie-Josée; Di Pietro, Antonio; Dufresne, Marie; Freitag, Michael; Grabherr, Manfred; Henrissat, Bernard; Houterman, Petra M.; Kang, Seogchan; Shim, Won-Bo; Woloshuk, Charles; Xie, Xiaohui; Xu, Jin-Rong; Antoniw, John; Baker, Scott E.; Bluhm, Burton H.; Breakspear, Andrew; Brown, Daren W.; Butchko, Robert A. E.; Chapman, Sinead; Coulson, Richard; Coutinho, Pedro M.; Danchin, Etienne G. J.; Diener, Andrew; Gale, Liane R.; Gardiner, Donald M.; Goff, Stephen; Hammond-Kosack, Kim E.; Hilburn, Karen; Hua-Van, Aurélie; Jonkers, Wilfried; Kazan, Kemal; Kodira, Chinnappa D.; Koehrsen, Michael; Kumar, Lokesh; Lee, Yong-Hwan; Li, Liande; Manners, John M.; Miranda-Saavedra, Diego; Mukherjee, Mala; Park, Gyungsoon; Park, Jongsun; Park, Sook-Young; Proctor, Robert H.; Regev, Aviv; Ruiz-Roldan, M. Carmen; Sain, Divya; Sakthikumar, Sharadha; Sykes, Sean; Schwartz, David C.; Turgeon, B. Gillian; Wapinski, Ilan; Yoder, Olen; Young, Sarah; Zeng, Qiandong; Zhou, Shiguo; Galagan, James; Cuomo, Christina A.; Kistler, H. Corby; Rep, Martijn

    2011-01-01

    Fusarium species are among the most important phytopathogenic and toxigenic fungi. To understand the molecular underpinnings of pathogenicity in the genus Fusarium, we compared the genomes of three phenotypically diverse species: Fusarium graminearum, Fusarium verticillioides and Fusarium oxysporum f. sp. lycopersici. Our analysis revealed lineage-specific (LS) genomic regions in F. oxysporum that include four entire chromosomes and account for more than one-quarter of the genome. LS regions are rich in transposons and genes with distinct evolutionary profiles but related to pathogenicity, indicative of horizontal acquisition. Experimentally, we demonstrate the transfer of two LS chromosomes between strains of F. oxysporum, converting a non-pathogenic strain into a pathogen. Transfer of LS chromosomes between otherwise genetically isolated strains explains the polyphyletic origin of host specificity and the emergence of new pathogenic lineages in F. oxysporum. These findings put the evolution of fungal pathogenicity into a new perspective. PMID:20237561

  17. Comparative genomics reveals mobile pathogenicity chromosomes in Fusarium

    SciTech Connect

    Ma, Li Jun; van der Does, H. C.; Borkovich, Katherine A.; Coleman, Jeffrey J.; Daboussi, Marie-Jose; Di Pietro, Antonio; Dufresne, Marie; Freitag, Michael; Grabherr, Manfred; Henrissat, Bernard; Houterman, Petra M.; Kang, Seogchan; Shim, Won-Bo; Wolochuk, Charles; Xie, Xiaohui; Xu, Jin Rong; Antoniw, John; Baker, Scott E.; Bluhm, Burton H.; Breakspear, Andrew; Brown, Daren W.; Butchko, Robert A.; Chapman, Sinead; Coulson, Richard; Coutinho, Pedro M.; Danchin, Etienne G.; Diener, Andrew; Gale, Liane R.; Gardiner, Donald; Goff, Steven; Hammond-Kossack, Kim; Hilburn, Karen; Hua-Van, Aurelie; Jonkers, Wilfried; Kazan, Kemal; Kodira, Chinnappa D.; Koehrsen, Michael; Kumar, Lokesh; Lee, Yong Hwan; Li, Liande; Manners, John M.; Miranda-Saavedra, Diego; Mukherjee, Mala; Park, Gyungsoon; Park, Jongsun; Park, Sook Young; Proctor, Robert H.; Regev, Aviv; Ruiz-Roldan, M. C.; Sain, Divya; Sakthikumar, Sharadha; Sykes, Sean; Schwartz, David C.; Turgeon, Barbara G.; Wapinski, Ilan; Yoder, Olen; Young, Sarah; Zeng, Qiandong; Zhou, Shiguo; Galagan, James; Cuomo, Christina A.; Kistler, H. Corby; Rep, Martijn

    2010-03-18

    Fusarium species are among the most important phytopathogenic and toxigenic fungi, having significant impact on crop production and animal health. Distinctively, members of the F. oxysporum species complex exhibit wide host range but discontinuously distributed host specificity, reflecting remarkable genetic adaptability. To understand the molecular underpinnings of diverse phenotypic traits and their evolution in Fusarium, we compared the genomes of three economically important and phylogenetically related, yet phenotypically diverse plant-pathogenic species, F. graminearum, F. verticillioides and F. oxysporum f. sp. lycopersici. Our analysis revealed greatly expanded lineage-specific (LS) genomic regions in F. oxysporum that include four entire chromosomes, accounting for more than one-quarter of the genome. LS regions are rich in transposons and genes with distinct evolutionary profiles but related to pathogenicity. Experimentally, we demonstrate for the first time the transfer of two LS chromosomes between strains of F. oxysporum, resulting in the conversion of a non-pathogenic strain into a pathogen. Transfer of LS chromosomes between otherwise genetically isolated strains explains the polyphyletic origin of host specificity and the emergence of new pathogenic lineages in the F. oxysporum species complex, putting the evolution of fungal pathogenicity into a new perspective.

  18. 76 FR 4046 - Highly Pathogenic Avian Influenza

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-01-24

    ...We are amending the regulations concerning the importation of animals and animal products to prohibit or restrict the importation of bird and poultry products from regions where any subtype of highly pathogenic avian influenza is considered to exist. We are also adding restrictions concerning importation of live poultry and birds that have been vaccinated for certain types of avian influenza,......

  19. 77 FR 34783 - Highly Pathogenic Avian Influenza

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-12

    ... avian influenza (HPAI). On January 24, 2011, we published in the Federal Register (76 FR 4046-4056... Avian Influenza AGENCY: Animal and Plant Health Inspection Service, USDA. ACTION: Interim rule... importation of bird and poultry products from regions where any subtype of highly pathogenic avian...

  20. Determinants of pathogenicity of H5N1 highly pathogenic avian influenza viruses in ducks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ducks have been implicated in the dissemination and evolution of the H5N1 highly pathogenic avian influenza (HPAI) viruses. The pathogenicity of H5N1 HPAI viruses in domestic ducks has increased over time with some viruses producing 100% mortality in very short time. The determinants of pathogenic...

  1. Are we aware how contaminated our mobile phones with nosocomial pathogens?

    PubMed Central

    Ulger, Fatma; Esen, Saban; Dilek, Ahmet; Yanik, Keramettin; Gunaydin, Murat; Leblebicioglu, Hakan

    2009-01-01

    Background The objective of this study was to determine the contamination rate of the healthcare workers' (HCWs') mobile phones and hands in operating room and ICU. Microorganisms from HCWs' hands could be transferred to the surfaces of the mobile phones during their use. Methods 200 HCWs were screened; samples from the hands of 200 participants and 200 mobile phones were cultured. Results In total, 94.5% of phones demonstrated evidence of bacterial contamination with different types of bacteria. The gram negative strains were isolated from mobile phones of 31.3% and the ceftazidime resistant strains from the hands were 39.5%. S. aureus strains isolated from mobile phones of 52% and those strains isolated from hands of 37.7% were methicillin resistant. Distributions of the isolated microorganisms from mobile phones were similar to hands isolates. Some mobile phones were contaminated with nosocomial important pathogens. Conclusion These results showed that HCWs' hands and their mobile phones were contaminated with various types of microorganisms. Mobile phones used by HCWs in daily practice may be a source of nosocomial infections in hospitals. PMID:19267892

  2. Horizontal Gene Acquisitions, Mobile Element Proliferation, and Genome Decay in the Host-Restricted Plant Pathogen Erwinia Tracheiphila.

    PubMed

    Shapiro, Lori R; Scully, Erin D; Straub, Timothy J; Park, Jihye; Stephenson, Andrew G; Beattie, Gwyn A; Gleason, Mark L; Kolter, Roberto; Coelho, Miguel C; De Moraes, Consuelo M; Mescher, Mark C; Zhaxybayeva, Olga

    2016-03-01

    Modern industrial agriculture depends on high-density cultivation of genetically similar crop plants, creating favorable conditions for the emergence of novel pathogens with increased fitness in managed compared with ecologically intact settings. Here, we present the genome sequence of six strains of the cucurbit bacterial wilt pathogen Erwinia tracheiphila (Enterobacteriaceae) isolated from infected squash plants in New York, Pennsylvania, Kentucky, and Michigan. These genomes exhibit a high proportion of recent horizontal gene acquisitions, invasion and remarkable amplification of mobile genetic elements, and pseudogenization of approximately 20% of the coding sequences. These genome attributes indicate that E. tracheiphila recently emerged as a host-restricted pathogen. Furthermore, chromosomal rearrangements associated with phage and transposable element proliferation contribute to substantial differences in gene content and genetic architecture between the six E. tracheiphila strains and other Erwinia species. Together, these data lead us to hypothesize that E. tracheiphila has undergone recent evolution through both genome decay (pseudogenization) and genome expansion (horizontal gene transfer and mobile element amplification). Despite evidence of dramatic genomic changes, the six strains are genetically monomorphic, suggesting a recent population bottleneck and emergence into E. tracheiphila's current ecological niche. PMID:26992913

  3. Horizontal Gene Acquisitions, Mobile Element Proliferation, and Genome Decay in the Host-Restricted Plant Pathogen Erwinia Tracheiphila

    PubMed Central

    Shapiro, Lori R.; Scully, Erin D.; Straub, Timothy J.; Park, Jihye; Stephenson, Andrew G.; Beattie, Gwyn A.; Gleason, Mark L.; Kolter, Roberto; Coelho, Miguel C.; De Moraes, Consuelo M.; Mescher, Mark C.; Zhaxybayeva, Olga

    2016-01-01

    Modern industrial agriculture depends on high-density cultivation of genetically similar crop plants, creating favorable conditions for the emergence of novel pathogens with increased fitness in managed compared with ecologically intact settings. Here, we present the genome sequence of six strains of the cucurbit bacterial wilt pathogen Erwinia tracheiphila (Enterobacteriaceae) isolated from infected squash plants in New York, Pennsylvania, Kentucky, and Michigan. These genomes exhibit a high proportion of recent horizontal gene acquisitions, invasion and remarkable amplification of mobile genetic elements, and pseudogenization of approximately 20% of the coding sequences. These genome attributes indicate that E. tracheiphila recently emerged as a host-restricted pathogen. Furthermore, chromosomal rearrangements associated with phage and transposable element proliferation contribute to substantial differences in gene content and genetic architecture between the six E. tracheiphila strains and other Erwinia species. Together, these data lead us to hypothesize that E. tracheiphila has undergone recent evolution through both genome decay (pseudogenization) and genome expansion (horizontal gene transfer and mobile element amplification). Despite evidence of dramatic genomic changes, the six strains are genetically monomorphic, suggesting a recent population bottleneck and emergence into E. tracheiphila’s current ecological niche. PMID:26992913

  4. Shigella: A Highly Virulent and Elusive Pathogen

    PubMed Central

    Estrada-García, Teresa

    2014-01-01

    Despite a significant decrease in Shigella-related mortality, shigellosis continues to carry a significant burden of disease worldwide, particularly in Asia and Africa. Shigella is a highly virulent pathogen comprised of four major species with numerous subtypes. Shigella dysenteriae and Shigella flexneri infections are predominant in resource-limited settings. Clinical presentations range from mild watery diarrhea to severe dysentery with systemic complications such as electrolyte imbalance, seizures and hemolytic uremic syndrome. S. dysenteriae subtype 1, the producer of Shiga toxin, causes the most severe illness and highest mortality. Susceptible strains of Shigella may be effectively treated with inexpensive oral antibiotics such as ampicillin or trimethoprim-sulfamethoxazole. Unfortunately, multidrug resistant strains have emerged that have rendered most antibiotics, including fluoroquinolones and extended-spectrum cephalosporins, ineffective. Management and prevention of shigellosis represents a major public health challenge. The development of an effective vaccine is urgently needed to decrease its global impact. PMID:25110633

  5. Pathogenicity of reassortant H5N1 highly pathogenic avian influenza viruses in domestic ducks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The pathogenicity of H5N1 highly pathogenic avian influenza (HPAI) viruses in domestic ducks has increased over time. These changes in virulence have been reported with viruses from countries with high population of domestic ducks, including Egypt. In order to understand which viral genes are contri...

  6. Compact USB-powered mobile ELISA-based pathogen detection: design and implementation challenges

    NASA Astrophysics Data System (ADS)

    Starodubov, Dmitry; Asanbaeva, Anya; Berezhnyy, Ihor; Chao, Chung-Yen; Koziol, Richard; Miller, David; Patton, Edward; Trehan, Sushma; Ulmer, Chris

    2011-05-01

    Physical Optics Corporation (POC) presents a novel Mobile ELISA-based Pathogen Detection system that is based on a disposable microfluidic chip for multiple-threat detection and a highly sensitive portable microfluidic fluorescence measurement unit that also controls the flow of samples and reagents through the microfluidic channels of the chip. The fluorescence detection subsystem is composed of a commercial 635-nm diode laser, an avalanche photodiode (APD) that measures fluorescence, and three filtering mirrors that provide more than 100 dB of excitation line suppression in the signal detection channel. Special techniques to suppress the fluorescence and scattering background allow optimizing the dynamic range for a compact package. Concentrations below 100 ng/mL can be reliably identified. The entire instrument is powered using a USB port of a notebook PC and operates as a plug-and-play human-interface device, resulting in a truly peripheral biosensor. The operation of the system is fully automated, with minimal user intervention through the detection process. The resolved challenges of the design and implementation are presented in detail in this publication.

  7. USGS highly pathogenic avian influenza research strategy

    USGS Publications Warehouse

    Harris, M. Camille; Miles, A. Keith; Pearce, John M.; Prosser, Diann J.; Sleeman, Jonathan M.; Whalen, Mary E.

    2015-01-01

    Avian influenza viruses are naturally occurring in wild birds such as ducks, geese, swans, and gulls. These viruses generally do not cause illness in wild birds, however, when spread to poultry they can be highly pathogenic and cause illness and death in backyard and commercial farms. Outbreaks may cause devastating agricultural economic losses and some viral strains have the potential to infect people directly. Furthermore, the combination of avian influenza viruses with mammalian viruses can result in strains with the ability to transmit from person to person, possibly leading to viruses with pandemic potential. All known pandemic influenza viruses have had some genetic material of avian origin. Since 1996, a strain of highly pathogenic avian influenza (HPAI) virus, H5N1, has caused infection in wild birds, losses to poultry farms in Eurasia and North Africa, and led to the deaths of several hundred people. Spread of the H5N1 virus and other influenza strains from China was likely facilitated by migratory birds. In December 2014, HPAI was detected in poultry in Canada and migratory birds in the United States. Since then, HPAI viruses have spread to large parts of the United States and will likely continue to spread through migratory bird flyways and other mechanisms throughout North America. In the United States, HPAI viruses have severely affected the poultry industry with millions of domestic birds dead or culled. These strains of HPAI are not known to cause disease in humans; however, the Centers for Disease Control and Prevention (CDC) advise caution when in close contact with infected birds. Experts agree that HPAI strains currently circulating in wild birds of North America will likely persist for the next few years. This unprecedented situation presents risks to the poultry industry, natural resource management, and potentially human health. Scientific knowledge and decision support tools are urgently needed to understand factors affecting the persistence

  8. Pathogenicity of two Egyptian H5N1 highly pathogenic avian influenza viruses in domestic ducks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Domestic ducks have been implicated in the dissemination and evolution of H5N1 highly pathogenic avian influenza (HPAI) viruses. Interestingly, the pathogenicity of H5N1 HPAI viruses in domestic ducks has increased over time with some viruses producing 100% mortality in ducks. These changes in vir...

  9. Providing Highly Mobile Students with an Effective Education. ERIC Digest.

    ERIC Educational Resources Information Center

    Walls, Charles A.

    The digest is a summary of the information presented in the monograph, "Students on the Move: Reaching and Teaching Highly Mobile Children and Youth". It describes the different reasons for high mobility and the characteristics of highly mobile families, explains the specific educational and social support needs of highly mobile students, and…

  10. Rapidly Expanding Range of Highly Pathogenic Avian Influenza Viruses

    PubMed Central

    Dusek, Robert J.; Spackman, Erica

    2015-01-01

    The movement of highly pathogenic avian influenza (H5N8) virus across Eurasia and into North America and the virus’ propensity to reassort with co-circulating low pathogenicity viruses raise concerns among poultry producers, wildlife biologists, aviculturists, and public health personnel worldwide. Surveillance, modeling, and experimental research will provide the knowledge required for intelligent policy and management decisions. PMID:26079209

  11. Rapidly expanding range of highly pathogenic avian influenza viruses

    USGS Publications Warehouse

    Hall, Jeffrey S.; Dusek, Robert J.; Spackman, Erica

    2015-01-01

    The movement of highly pathogenic avian influenza (H5N8) virus across Eurasia and into North America and the virus’ propensity to reassort with co-circulating low pathogenicity viruses raise concerns among poultry producers, wildlife biologists, aviculturists, and public health personnel worldwide. Surveillance, modeling, and experimental research will provide the knowledge required for intelligent policy and management decisions.

  12. Mobile high frequency vibrator system

    SciTech Connect

    Fair, D.W.; Buller, P.L.

    1985-01-08

    A carrier mounted seismic vibrator system that is primarily adapted for generation of high force, high frequency seismic energy into an earth medium. The apparatus includes first and second vibrators as supported by first and second lift systems disposed in tandem juxtaposition generally centrally in said vehicle, and the lift systems are designed to maintain equal hold-down force on the vibrator coupling baseplates without exceeding the weight of the carrier vehicle. The juxtaposed vibrators are then energized in synchronized relationship to propagate increased amounts of higher frequency seismic energy into an earth medium.

  13. High mobility annealing of Transparent Conductive Oxides

    NASA Astrophysics Data System (ADS)

    Warzecha, M.; Owen, J. I.; Wimmer, M.; Ruske, F.; Hotovy, J.; Hüpkes, J.

    2012-04-01

    To improve electrical properties a high temperature annealing treatment was applied to several transparent conductive oxides (TCO), namely tin doped indium oxide (ITO), Ga- or Al- doped ZnO (ZnO:Al/Ga), ion beam assisted deposited (IBAD) ZnO:Ga and Ga doped zinc magnesium oxide (ZnMgO:Ga). All these films were grown by magnetron sputtering. During the annealing process all TCO films were capped with 50 nm of amorphous silicon in order to protect the films from environmental impact. Increase in mobility up to 72 cm2/Vs and low resistivity of 1.6 × 10-4 Ωcm was achieved for ZnO:Al after annealing at 650°C for 24 h. Independent of the deposition conditions and doping or alloying material almost all ZnO based films show a consistent improvement in mobility. Also for ITO films a decrease in resistivity with partially improved mobility was found after annealing. However, not all ITO films show consistent improvement, but carrier density above 1021 cm-3 while ZnO films show no clear trend for carrier density but a remarkable increase in mobility. Thus we propose the healing of defects and the activation of donors to be most significant effects for ZnO and ITO films, respectively.

  14. Analytical admittance characterization of high mobility channel

    SciTech Connect

    Mammeri, A. M.; Mahi, F. Z.; Varani, L.

    2015-03-30

    In this contribution, we investigate the small-signal admittance of the high electron mobility transistors field-effect channels under a continuation branching of the current between channel and gate by using an analytical model. The analytical approach takes into account the linearization of the 2D Poisson equation and the drift current along the channel. The analytical equations discuss the frequency dependence of the admittance at source and drain terminals on the geometrical transistor parameters.

  15. Highly mobile oxygen holes in magnesium oxide

    NASA Technical Reports Server (NTRS)

    Freund, Minoru M.; Freund, Friedemann; Batllo, Francois

    1989-01-01

    High-purity MgO exhibits an unexpected giant anomaly of the apparent static dielectric constant and a positive surface charge of the order of 5 x 10 to the 21st/cu cm in the top 15 nm. It is postulated that the MgO matrix contains traces of peroxy defects, O2(2-), associated with Mg(2+) vacancies. Above approximately 400 C the O2(2-) dissociates to vacancy bound O(-) and highly mobile O(-) states, which diffuse to the surface, giving rise to a high surface conductivity.

  16. The gene for toxic shock toxin is carried by a family of mobile pathogenicity islands in Staphylococcus aureus.

    PubMed

    Lindsay, J A; Ruzin, A; Ross, H F; Kurepina, N; Novick, R P

    1998-07-01

    Tst, the gene for toxic shock syndrome toxin-1 (TSST-1), is part of a 15.2 kb genetic element in Staphylococcus aureus that is absent in TSST-1-negative strains. The prototype, in RN4282, is flanked by a 17 nucleotide direct repeat and contains genes for a second possible superantigen toxin, a Dichelobacter nodosus VapE homologue and a putative integrase. It is readily transferred to a recA recipient, and it always inserts into a unique chromosomal copy of the 17 nucleotide sequence in the same orientation. It is excised and circularized by staphylococcal phages phi13 and 80alpha and replicates during the growth of the latter, which transduces it at very high frequency. Because of its site and orientation specificity and because it lacks other identifiable phage-like genes, we consider it to be a pathogenicity island (PI) rather than a transposon or a defective phage. The tst element in RN4282, near tyrB, is designated SaPI1. That in RN3984 in the trp region is only partially homologous to SaPI1 and is excised by phage 80 but not by 80alpha. It is designated SaPI2. These PIs are the first in any gram-positive species and the first for which mobility has been demonstrated. Their mobility may be responsible for the spread of TSST-1 production among S. aureus strains. PMID:9720870

  17. Persistence of Highly Pathogenic Avian Influenza Viruses in Natural Ecosystems

    PubMed Central

    Feare, Chris J.; Renaud, François; Thomas, Frédéric; Gauthier-Clerc, Michel

    2010-01-01

    Understanding of ecologic factors favoring emergence and maintenance of highly pathogenic avian influenza (HPAI) viruses is limited. Although low pathogenic avian influenza viruses persist and evolve in wild populations, HPAI viruses evolve in domestic birds and cause economically serious epizootics that only occasionally infect wild populations. We propose that evolutionary ecology considerations can explain this apparent paradox. Host structure and transmission possibilities differ considerably between wild and domestic birds and are likely to be major determinants of virulence. Because viral fitness is highly dependent on host survival and dispersal in nature, virulent forms are unlikely to persist in wild populations if they kill hosts quickly or affect predation risk or migratory performance. Interhost transmission in water has evolved in low pathogenic influenza viruses in wild waterfowl populations. However, oropharyngeal shedding and transmission by aerosols appear more efficient for HPAI viruses among domestic birds. PMID:20587174

  18. High-throughput proteomics and the fight against pathogens.

    PubMed

    Horvatić, Anita; Kuleš, Josipa; Guillemin, Nicolas; Galan, Asier; Mrljak, Vladimir; Bhide, Mangesh

    2016-07-19

    Pathogens pose a major threat to human and animal welfare. Understanding the interspecies host-pathogen protein-protein interactions could lead to the development of novel strategies to combat infectious diseases through the rapid development of new therapeutics. The first step in understanding the host-pathogen crosstalk is to identify interacting proteins in order to define crucial hot-spots in the host-pathogen interactome, such as the proposed pharmaceutical targets by means of high-throughput proteomic methodologies. In order to obtain holistic insight into the inter- and intra-species bimolecular interactions, apart from the proteomic approach, sophisticated in silico modeling is used to correlate the obtained large data sets with other omics data and clinical outcomes. Since the main focus in this area has been directed towards human medicine, it is time to extrapolate the existing expertise to a new emerging field: the 'systems veterinary medicine'. Therefore, this review addresses high-throughput mass spectrometry-based technology for monitoring protein-protein interactions in vitro and in vivo and discusses pathogen cultivation, model host cells and available bioinformatic tools employed in vaccine development. PMID:27227577

  19. Miniature Transposable Sequences Are Frequently Mobilized in the Bacterial Plant Pathogen Pseudomonas syringae pv. phaseolicola

    PubMed Central

    Bardaji, Leire; Añorga, Maite; Jackson, Robert W.; Martínez-Bilbao, Alejandro; Yanguas-Casás, Natalia; Murillo, Jesús

    2011-01-01

    Mobile genetic elements are widespread in Pseudomonas syringae, and often associate with virulence genes. Genome reannotation of the model bean pathogen P. syringae pv. phaseolicola 1448A identified seventeen types of insertion sequences and two miniature inverted-repeat transposable elements (MITEs) with a biased distribution, representing 2.8% of the chromosome, 25.8% of the 132-kb virulence plasmid and 2.7% of the 52-kb plasmid. Employing an entrapment vector containing sacB, we estimated that transposition frequency oscillated between 2.6×10−5 and 1.1×10−6, depending on the clone, although it was stable for each clone after consecutive transfers in culture media. Transposition frequency was similar for bacteria grown in rich or minimal media, and from cells recovered from compatible and incompatible plant hosts, indicating that growth conditions do not influence transposition in strain 1448A. Most of the entrapped insertions contained a full-length IS801 element, with the remaining insertions corresponding to sequences smaller than any transposable element identified in strain 1448A, and collectively identified as miniature sequences. From these, fragments of 229, 360 and 679-nt of the right end of IS801 ended in a consensus tetranucleotide and likely resulted from one-ended transposition of IS801. An average 0.7% of the insertions analyzed consisted of IS801 carrying a fragment of variable size from gene PSPPH_0008/PSPPH_0017, showing that IS801 can mobilize DNA in vivo. Retrospective analysis of complete plasmids and genomes of P. syringae suggests, however, that most fragments of IS801 are likely the result of reorganizations rather than one-ended transpositions, and that this element might preferentially contribute to genome flexibility by generating homologous regions of recombination. A further miniature sequence previously found to affect host range specificity and virulence, designated MITEPsy1 (100-nt), represented an average 2.4% of the total

  20. Pathogenicity comparison between highly pathogenic and NADC30-like porcine reproductive and respiratory syndrome virus.

    PubMed

    Sun, Zhe; Wang, Juan; Bai, Xiaofei; Ji, Guobiao; Yan, He; Li, Yingying; Wang, Yuzhou; Tan, Feifei; Xiao, Yan; Li, Xiangdong; Tian, Kegong

    2016-08-01

    The pathogenicity of HNjz15, an NADC30-like strain of porcine reproductive and respiratory syndrome virus (PRRSV), was investigated and compared to that of a highly pathogenic PRRSV JAX1 strain. Six-week-old pigs infected with each virus showed typical clinical symptoms, including high fever and respiratory disorders. Pigs infected with JXA1 had more-severe clinical manifestations than pigs infected with HNjz15. HNjz15 replicated in vivo with kinetics similar to those of JXA1 but induced a lower level of PRRSV-specific antibody at the beginning of virus infection. Histopathologically, JXA1 infection led to more-severe lung lesions and broader organ tropism than HNjz15 did. Different from what was observed with the previously reported NADC30-like PRRSV JL580 strain, all HNjz15-infected pigs survived until the end of the study. All of these results indicated that NADC30-like PRRSV HNjz15 is virulent to pigs but is less pathogenic than the JXA1 and JL580 PRRSV strains. PMID:27151278

  1. Highly pathogenic avian influenza virus among wild birds in Mongolia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The central Asian country of Mongolia supports large populations of migratory water birds that migrate across much of Asia where highly pathogenic avian influenza (HPAI) virus subtype H5N1 is endemic. This, together with the near absence of domestic poultry, makes Mongolia an ideal location to unde...

  2. Highly Pathogenic Avian Influenza: Intersecting Humans, Animals, and the Environment

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Eurasian-African H5N1 highly pathogenic avian influenza (HPAI) virus has caused an unprecedented epizootic affecting mainly poultry, but has crossed multiple species barriers to infect captive and wild birds, carnivorous mammals and humans. There is still great concern over the continued infecti...

  3. Rapidly expanding range of highly pathogenic avian influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The recent introduction of highly pathogenic avian influenza virus (HPAIV) H5N8 into Europe and North America poses significant risks to poultry industries and wildlife populations and warrants continued and heightened vigilance. First discovered in South Korean poultry and wild birds in early 2014...

  4. Highly pathogenic fowlpox virus in cutaneously infected chickens, China.

    PubMed

    Zhao, Kui; He, Wenqi; Xie, Shengnan; Song, Deguang; Lu, Huijun; Pan, Wei; Zhou, Ping; Liu, Wenfeng; Lu, Rongguang; Zhou, Jiyong; Gao, Feng

    2014-07-01

    We investigated an acute outbreak of the cutaneous form of fowlpox among chickens in China in November 2009. Using pathologic and virologic methods, we identified a novel type of fowlpox virus that carried an integrated genomic sequence of reticuloendotheliosis virus. This highly pathogenic virus could lead to severe ecologic effects and economic losses. PMID:24963887

  5. Pathogenicity, Transmission and Antigenic Variation of H5N1 Highly Pathogenic Avian Influenza Viruses

    PubMed Central

    Jiao, Peirong; Song, Hui; Liu, Xiaoke; Song, Yafen; Cui, Jin; Wu, Siyu; Ye, Jiaqi; Qu, Nanan; Zhang, Tiemin; Liao, Ming

    2016-01-01

    H5N1 highly pathogenic avian influenza (HPAI) was one of the most important avian diseases in poultry production of China, especially in Guangdong province. In recent years, new H5N1 highly pathogenic avian influenza viruses (HPAIV) still emerged constantly, although all poultry in China were immunized with H5N1 vaccinations compulsorily. To better understand the pathogenicity and transmission of dominant clades of the H5N1 HPAIVs in chicken from Guangdong in 2012, we chose a clade 7.2 avian influenza virus named A/Chicken/China/G2/2012(H5N1) (G2) and a clade 2.3.2.1 avian influenza virus named A/Duck/China/G3/2012(H5N1) (G3) in our study. Our results showed that the chickens inoculated with 103 EID50 of G2 or G3 viruses all died, and the titers of virus replication detected in several visceral organs were high but different. In the naive contact groups, virus shedding was not detected in G2 group and all chickens survived, but virus shedding was detected in G3 group and all chickens died. These results showed that the two clades of H5N1 HPAIVs had high pathogenicity in chickens and the contact transmission of them was different in chickens. The results of cross reactive HI assay showed that antigens of G2 and G3 were very different from those of current commercial vaccines isolates (Re-4, Re-6, and D7). And to evaluate the protective efficacy of three vaccines against most isolates form Guangdong belonging to clade 2.3.2.1 in 2012, G3 was chosen to challenge the three vaccines such as Re-4, Re-6, and D7. First, chickens were immunized with 0.3 ml Re-4, Re-6, and D7 inactivated vaccines by intramuscular injection, respectively, and then challenged with 106 EID50 of G3 on day 28 post-vaccination. The D7 vaccine had 100% protection against G3 for chickens, the Re-6 vaccine had 88.9%, and the Re-4 vaccine only had 66.7%. Our results suggested that the D7 vaccine could prevent and control H5N1 virus outbreaks more effectively in Guangdong. From the above, it was

  6. Imperfect Vaccination Can Enhance the Transmission of Highly Virulent Pathogens

    PubMed Central

    Read, Andrew F.; Baigent, Susan J.; Powers, Claire; Kgosana, Lydia B.; Blackwell, Luke; Smith, Lorraine P.; Kennedy, David A.; Walkden-Brown, Stephen W.; Nair, Venugopal K.

    2015-01-01

    Could some vaccines drive the evolution of more virulent pathogens? Conventional wisdom is that natural selection will remove highly lethal pathogens if host death greatly reduces transmission. Vaccines that keep hosts alive but still allow transmission could thus allow very virulent strains to circulate in a population. Here we show experimentally that immunization of chickens against Marek's disease virus enhances the fitness of more virulent strains, making it possible for hyperpathogenic strains to transmit. Immunity elicited by direct vaccination or by maternal vaccination prolongs host survival but does not prevent infection, viral replication or transmission, thus extending the infectious periods of strains otherwise too lethal to persist. Our data show that anti-disease vaccines that do not prevent transmission can create conditions that promote the emergence of pathogen strains that cause more severe disease in unvaccinated hosts. PMID:26214839

  7. Emergence of a Highly Pathogenic Avian Influenza Virus from a Low-Pathogenic Progenitor

    PubMed Central

    Fusaro, Alice; Nelson, Martha I.; Bonfanti, Lebana; Mulatti, Paolo; Hughes, Joseph; Murcia, Pablo R.; Schivo, Alessia; Valastro, Viviana; Moreno, Ana; Holmes, Edward C.; Cattoli, Giovanni

    2014-01-01

    ABSTRACT Avian influenza (AI) viruses of the H7 subtype have the potential to evolve into highly pathogenic (HP) viruses that represent a major economic problem for the poultry industry and a threat to global health. However, the emergence of HPAI viruses from low-pathogenic (LPAI) progenitor viruses currently is poorly understood. To investigate the origin and evolution of one of the most important avian influenza epidemics described in Europe, we investigated the evolutionary and spatial dynamics of the entire genome of 109 H7N1 (46 LPAI and 63 HPAI) viruses collected during Italian H7N1 outbreaks between March 1999 and February 2001. Phylogenetic analysis revealed that the LPAI and HPAI epidemics shared a single ancestor, that the HPAI strains evolved from the LPAI viruses in the absence of reassortment, and that there was a parallel emergence of mutations among HPAI and later LPAI lineages. Notably, an ultradeep-sequencing analysis demonstrated that some of the amino acid changes characterizing the HPAI virus cluster were already present with low frequency within several individual viral populations from the beginning of the LPAI H7N1 epidemic. A Bayesian phylogeographic analysis revealed stronger spatial structure during the LPAI outbreak, reflecting the more rapid spread of the virus following the emergence of HPAI. The data generated in this study provide the most complete evolutionary and phylogeographic analysis of epidemiologically intertwined high- and low-pathogenicity viruses undertaken to date and highlight the importance of implementing prompt eradication measures against LPAI to prevent the appearance of viruses with fitness advantages and unpredictable pathogenic properties. IMPORTANCE The Italian H7 AI epidemic of 1999 to 2001 was one of the most important AI outbreaks described in Europe. H7 viruses have the ability to evolve into HP forms from LP precursors, although the mechanisms underlying this evolutionary transition are only poorly

  8. Mobility and Student Achievement in High Poverty Schools

    ERIC Educational Resources Information Center

    Dalton, Janet Denise

    2013-01-01

    Student mobility is an issue for high poverty schools in the shadow of increased rigor and accountability for student performance. Whereas mobility is not a sole cause for poor achievement, it is a contributing factor for students in poverty who are already considered to be at risk of low achievement. Student mobility creates a hardship for…

  9. A Mobile Learning Module for High School Fieldwork

    ERIC Educational Resources Information Center

    Hsu, Tzu-Yen; Chen, Che-Ming

    2010-01-01

    Although fieldwork is always cited as an important component of geographic education, there are many obstacles for executing high school fieldwork. Mobile electronic products are becoming popular and some schools are able to acquire these devices for mobile learning. This study attempts to provide a mobile-assisted means of guiding students…

  10. Decontamination of High-risk Animal and Zoonotic Pathogens

    PubMed Central

    Menrath, Andrea; Tomuzia, Katharina; Braeunig, Juliane; Appel, Bernd

    2013-01-01

    Preparedness for the decontamination of affected environments, premises, facilities, and products is one prerequisite for an immediate response to an animal disease outbreak. Various information sources provide recommendations on how to proceed in an outbreak situation to eliminate biological contaminants and to stop the spread of the disease. In order to facilitate the identification of the right decontamination strategy, we present an overview of relevant references for a collection of pathogenic agents. The choice of pathogens is based on a survey of lists containing highly pathogenic agents and/or biological agents considered to be potential vehicles for deliberate contamination of food, feed, or farm animals. European legislation and guidelines from national and international institutions were screened to find decontamination protocols for each of the agents. Identified recommendations were evaluated with regard to their area of application, which could be facilities and equipment, wastes, food, and other animal products. The requirements of a disinfectant for large-scale incidents were gathered, and important characteristics (eg, inactivating spectrum, temperature range, toxicity to environment) of the main recommended disinfectants were summarized to assist in the choice of a suitable and efficient approach in a crisis situation induced by a specific high-risk animal or zoonotic pathogen. The literature search revealed numerous relevant recommendations but also legal gaps for certain diseases, such as Q fever or brucellosis, and legal difficulties for the use of recommended disinfectants. A lack of information about effective disinfectants was identified for some agents. PMID:23971795

  11. Decontamination of high-risk animal and zoonotic pathogens.

    PubMed

    Frentzel, Hendrik; Menrath, Andrea; Tomuzia, Katharina; Braeunig, Juliane; Appel, Bernd

    2013-09-01

    Preparedness for the decontamination of affected environments, premises, facilities, and products is one prerequisite for an immediate response to an animal disease outbreak. Various information sources provide recommendations on how to proceed in an outbreak situation to eliminate biological contaminants and to stop the spread of the disease. In order to facilitate the identification of the right decontamination strategy, we present an overview of relevant references for a collection of pathogenic agents. The choice of pathogens is based on a survey of lists containing highly pathogenic agents and/or biological agents considered to be potential vehicles for deliberate contamination of food, feed, or farm animals. European legislation and guidelines from national and international institutions were screened to find decontamination protocols for each of the agents. Identified recommendations were evaluated with regard to their area of application, which could be facilities and equipment, wastes, food, and other animal products. The requirements of a disinfectant for large-scale incidents were gathered, and important characteristics (eg, inactivating spectrum, temperature range, toxicity to environment) of the main recommended disinfectants were summarized to assist in the choice of a suitable and efficient approach in a crisis situation induced by a specific high-risk animal or zoonotic pathogen. The literature search revealed numerous relevant recommendations but also legal gaps for certain diseases, such as Q fever or brucellosis, and legal difficulties for the use of recommended disinfectants. A lack of information about effective disinfectants was identified for some agents. PMID:23971795

  12. Subsurface Transport and Mobilization of Pathogenic Microbes and Microspheres: Effect of Microbe Size, Soil Physical Heterogeneity, and Intermittent Flow

    NASA Astrophysics Data System (ADS)

    Bulicek, M. C.; Metge, D. W.; Mohanty, S. K.; Harvey, R. W.; Ryan, J. N.

    2013-12-01

    Intermittent flows of rainwater frequently mobilize pathogenic microbes attached to subsurface soils, thereby causing groundwater contamination. The potential of intermittent rainfall to mobilize diverse pathogens (e.g., size, shape, taxa) remains understudied for heterogeneous soil systems. This study investigates the combined effects of microbe size and shape, intermittent flow, and soil physical heterogeneity on the transport, retention and mobilization of microbes through an intact, fractured shale saprolite core. Microbes, including MS-2 bacteriophage (~26 nm), Pseudomonas stutzeri bacteria (~1 μm), and Cryptosporidium parvum oocysts (3.6 μm), and 0.5 μm fluorescent microspheres (FMS), preceded by a bromide tracer, were applied to the core to obtain breakthrough. After breakthrough, the core was subjected to intermittent rainfalls to mobilize the attached microbes and FMS. Water samples were collected using 19 spatially-arranged outlet ports at the core base to resolve the effect of soil physical heterogeneity. Water infiltrated through only eight of 19 total sampling ports, which indicated water partially bypassed soil matrices and infiltrated through macropores. Bromide recovery was less than 100%, which indicated diffusion of bromide into the soil matrix. Macropores and the soil matrix dominated flow were characterized based on the cumulative bromide recovery within individual sampling ports. Thus, lower recovery was attributed to increased matrix diffusion and higher recovery indicated the presence of macropores. Intermittent flow mobilized previously sequestered microbes and FMS; however, mobilization varied with the size of microbes/FMS and sampling ports. Greater mobilization occurred through macropores compared to soil matrices. Mobilization of larger, spherical C. parvum oocysts was greater than that of the smaller, spherical MS-2 bacteriophage and the rod-shaped P. stutzeri bacteria during intermittent flow. This suggested shear forces mobilize

  13. The Type 2 dUTPase of Bacteriophage ϕNM1 Initiates Mobilization of Staphylococcus aureus Bovine Pathogenicity Island 1.

    PubMed

    Hill, Rosanne L L; Dokland, Terje

    2016-01-16

    Staphylococcus aureus pathogenicity islands (SaPIs) are genetic elements that are mobilized by specific helper phages. The initial step in mobilization is the derepression of the SaPI by the interaction of a phage protein with the SaPI master repressor Stl. Stl proteins are highly divergent between different SaPIs and respond to different phage-encoded derepressors. One such SaPI, SaPIbov1, is derepressed by the dUTPase (Dut) of bacteriophage 80α (Dut80α) and its phage ϕ11 homolog, Dut11. We previously showed that SaPIbov1 could also be mobilized by phage ϕNM1, even though its dut gene is not homologous with that of 80α. Here, we show that ϕNM1 dut encodes a type 2 dUTPase (DutNM1), which has an α-helical structure that is distinct from the type 1 trimeric, β-sheet structure of Dut80α. Deletion of dutNM1 abolishes the ability of ϕNM1 to mobilize SaPIbov1. Like Dut80α, DutNM1 forms a direct interaction with SaPIbov1 Stl both in vivo and in vitro, leading to inhibition of the dUTPase activity and Stl release from its target DNA. This work provides novel insights into the diverse mechanisms of genetic mobilization in S. aureus. PMID:26585401

  14. Identification of a modular pathogenicity island that is widespread among urease-producing uropathogens and shares features with a diverse group of mobile elements.

    PubMed

    Flannery, Erika L; Mody, Lona; Mobley, Harry L T

    2009-11-01

    Pathogenicity islands (PAIs) are a specific group of genomic islands that contribute to genomic variability and virulence of bacterial pathogens. Using a strain-specific comparative genomic hybridization array, we report the identification of a 94-kb PAI, designated ICEPm1, that is common to Proteus mirabilis, Providencia stuartii, and Morganella morganii. These organisms are highly prevalent etiologic agents of catheter-associated urinary tract infections (caUTI), the most common hospital acquired infection. ICEPm1 carries virulence factors that are important for colonization of the urinary tract, including a known toxin (Proteus toxic agglutinin) and the high pathogenicity island of Yersinia spp. In addition, this PAI shares homology and gene organization similar to the PAIs of other bacterial pathogens, several of which have been classified as mobile integrative and conjugative elements (ICEs). Isolates from this study were cultured from patients with caUTI and show identical sequence similarity at three loci within ICEPm1, suggesting its transfer between bacterial genera. Screening for the presence of ICEPm1 among P. mirabilis colonizing isolates showed that ICEPm1 is more prevalent in urine isolates compared to P. mirabilis strains isolated from other body sites (P<0.0001), further suggesting that it contributes to niche specificity and is positively selected for in the urinary tract. PMID:19687197

  15. High mobility diamonds and particle detectors

    NASA Astrophysics Data System (ADS)

    Pernegger, H.

    2006-10-01

    The basic properties of high-quality CVD diamond film make them very interesting for a wide range of detectors: they are radiation hard, provide fast signals, show very low leakage current even in high radiation environments, have excellent thermal properties and can be manufactured as free-standing detectors. This paper will give an overview of recent test results on polycrystalline and single crystal CVD diamond detectors. Large polycrystalline CVD diamonds with a charge collection distance up to 300 m have been tested and are used to build prototype tracking detectors and beam monitors at the moment. Further irradiation studies have been carried out using a 24 GeV proton beam to test samples up to a total fluence of 1.8 × 1016 protons/cm2. Measurements on several samples of single-crystal CVD diamonds have shown full charge collection in the detector. Results of transient-current measurements on single crystal CVD diamonds, which are used to determine the charge carrier mobility and lifetime, show the excellent electrical properties of this material. The paper will present several different applications of CVD diamond detectors, which benefit from the recent improvements of detector-grade diamonds. They range from tracking in High Energy Physics experiments, to high-speed Beam Conditions Monitor at the collider experiments up to CVD diamond detectors as beam diagnostic in proton cancer therapy.

  16. High seroprevalence of respiratory pathogens in hobby poultry.

    PubMed

    Haesendonck, R; Verlinden, M; Devos, G; Michiels, T; Butaye, P; Haesebrouck, F; Pasmans, F; Martel, A

    2014-12-01

    Seroprevalence studies on respiratory pathogens have been done extensively in commercial laying hens, broilers, and, to a lesser extent, backyard poultry. In Europe, seroprevalence studies in backyard and fancy breed poultry flocks are scarce and limited to a few pathogens, such as Mycoplasma gallisepticum (MG); others, such as Ornithobacterium rhinotracheale (ORT), are missing. A commercial ELISA for detection of antibodies against six selected pathogens was performed on 460 serum samples from chickens across Flanders. Anti-ORT antibodies were, by far, the most prevalent, with a prevalence of 95.4%. Infectious bronchitis virus, Mycoplasma synoviae, and avian metapneumovirus antibodies were found in 75.6%, 76.3%, and 63.5% of the animals, respectively. Antibodies against MG and infectious laryngotracheitis virus were found in 36.7% and 30% of the animals, respectively. These data demonstrate the high seroprevalence of respiratory pathogens among hobby poultry; therefore, it is possible that this group could act as a reservoir for commercially kept poultry. PMID:25619008

  17. Identification of peptidases in highly pathogenic vs. weakly pathogenic Naegleria fowleri amebae.

    PubMed

    Vyas, Ishan K; Jamerson, Melissa; Cabral, Guy A; Marciano-Cabral, Francine

    2015-01-01

    Naegleria fowleri, a free-living ameba, is the causative agent of Primary Amebic Meningoencephalitis. Highly pathogenic mouse-passaged amebae (Mp) and weakly pathogenic axenically grown (Ax) N. fowleri were examined for peptidase activity. Zymography and azocasein peptidase activity assays demonstrated that Mp and Ax N. fowleri exhibited a similar peptidase pattern. Prominent for whole cell lysates, membranes and conditioned medium (CM) from Mp and Ax amebae was the presence of an activity band of approximately 58 kDa that was sensitive to E64, a cysteine peptidase inhibitor. However, axenically grown N. fowleri demonstrated a high level of this peptidase activity in membrane preparations. The inhibitor E64 also reduced peptidase activity in ameba-CM consistent with the presence of secreted cysteine peptidases. Exposure of Mp amebae to E64 reduced their migration through matrigel that was used as an extracellular matrix, suggesting a role for cysteine peptidases in invasion of the central nervous system (CNS). The collective results suggest that the profile of peptidases is not a discriminative marker for distinguishing Mp from Ax N. fowleri. However, the presence of a prominent level of activity for cysteine peptidases in N. fowleri membranes and CM, suggests that these enzymes may serve to facilitate passage of the amebae into the CNS. PMID:25066578

  18. A Highly Secure Mobile Agent System Architecture

    NASA Astrophysics Data System (ADS)

    Okataku, Yasukuni; Okutomi, Hidetoshi; Yoshioka, Nobukazu; Ohgishi, Nobuyuki; Honiden, Shinichi

    We propose a system architecture for mobile agents to improve their security in the environments of insecure networks and non-sophisticated terminals such as PDAs. As mobile agents freely migrate onto their favorite terminals through insecure networks or terminals, it is not appropriate for them to store some secret information for authentication and encryption/decryption. We introduce one and more secure nodes(OASIS NODE) for securely generating and verifying authentication codes. The each agent’s data are encrypted by a pseudo-chaos cipher mechanism which doesn’t need any floating processing co-processor. We’ve constructed a prototype system on a Java mobile agent framework, “Bee-gent" which implements the proposed authentication and cipher mechanisms, and evaluated their performances and their applicability to business fields such as an auction system by mobile agents.

  19. Quantifying Transmission of Highly Pathogenic and Low Pathogenicity H7N1 Avian Influenza in Turkeys

    PubMed Central

    Saenz, Roberto A.; Essen, Steve C.; Brookes, Sharon M.; Iqbal, Munir; Wood, James L. N.; Grenfell, Bryan T.; McCauley, John W.; Brown, Ian H.; Gog, Julia R.

    2012-01-01

    Outbreaks of avian influenza in poultry can be devastating, yet many of the basic epidemiological parameters have not been accurately characterised. In 1999–2000 in Northern Italy, outbreaks of H7N1 low pathogenicity avian influenza virus (LPAI) were followed by the emergence of H7N1 highly pathogenic avian influenza virus (HPAI). This study investigates the transmission dynamics in turkeys of representative HPAI and LPAI H7N1 virus strains from this outbreak in an experimental setting, allowing direct comparison of the two strains. The fitted transmission rates for the two strains are similar: 2.04 (1.5–2.7) per day for HPAI, 2.01 (1.6–2.5) per day for LPAI. However, the mean infectious period is far shorter for HPAI (1.47 (1.3–1.7) days) than for LPAI (7.65 (7.0–8.3) days), due to the rapid death of infected turkeys. Hence the basic reproductive ratio, is significantly lower for HPAI (3.01 (2.2–4.0)) than for LPAI (15.3 (11.8–19.7)). The comparison of transmission rates and are critically important in relation to understanding how HPAI might emerge from LPAI. Two competing hypotheses for how transmission rates vary with population size are tested by fitting competing models to experiments with differing numbers of turkeys. A model with frequency-dependent transmission gives a significantly better fit to experimental data than density-dependent transmission. This has important implications for extrapolating experimental results from relatively small numbers of birds to the commercial poultry flock size, and for how control, including vaccination, might scale with flock size. PMID:23028760

  20. High-Level Fluorescence Labeling of Gram-Positive Pathogens

    PubMed Central

    Aymanns, Simone; Mauerer, Stefanie; van Zandbergen, Ger; Wolz, Christiane; Spellerberg, Barbara

    2011-01-01

    Fluorescence labeling of bacterial pathogens has a broad range of interesting applications including the observation of living bacteria within host cells. We constructed a novel vector based on the E. coli streptococcal shuttle plasmid pAT28 that can propagate in numerous bacterial species from different genera. The plasmid harbors a promoterless copy of the green fluorescent variant gene egfp under the control of the CAMP-factor gene (cfb) promoter of Streptococcus agalactiae and was designated pBSU101. Upon transfer of the plasmid into streptococci, the bacteria show a distinct and easily detectable fluorescence using a standard fluorescence microscope and quantification by FACS-analysis demonstrated values that were 10–50 times increased over the respective controls. To assess the suitability of the construct for high efficiency fluorescence labeling in different gram-positive pathogens, numerous species were transformed. We successfully labeled Streptococcus pyogenes, Streptococcus agalactiae, Streptococcus dysgalactiae subsp. equisimilis, Enterococcus faecalis, Enterococcus faecium, Streptococcus mutans, Streptococcus anginosus and Staphylococcus aureus strains utilizing the EGFP reporter plasmid pBSU101. In all of these species the presence of the cfb promoter construct resulted in high-level EGFP expression that could be further increased by growing the streptococcal and enterococcal cultures under high oxygen conditions through continuous aeration. PMID:21731607

  1. Learning on the Go: Voices of Highly Mobile Urban Students

    ERIC Educational Resources Information Center

    Rhodes, Virginia L.

    2008-01-01

    Highly mobile students experience schools and learning in different ways than their more stable peers. Repeated transfers result in discontinuity of instruction and relationships with teachers and peers. Interviews with transient urban students in grades 9-12 reveal the issues they face upon their arrival and afterward. Mobile students give…

  2. Micromagnetics on high-performance workstation and mobile computational platforms

    NASA Astrophysics Data System (ADS)

    Fu, S.; Chang, R.; Couture, S.; Menarini, M.; Escobar, M. A.; Kuteifan, M.; Lubarda, M.; Gabay, D.; Lomakin, V.

    2015-05-01

    The feasibility of using high-performance desktop and embedded mobile computational platforms is presented, including multi-core Intel central processing unit, Nvidia desktop graphics processing units, and Nvidia Jetson TK1 Platform. FastMag finite element method-based micromagnetic simulator is used as a testbed, showing high efficiency on all the platforms. Optimization aspects of improving the performance of the mobile systems are discussed. The high performance, low cost, low power consumption, and rapid performance increase of the embedded mobile systems make them a promising candidate for micromagnetic simulations. Such architectures can be used as standalone systems or can be built as low-power computing clusters.

  3. 143. MOBILE HIGH PRESSURE NITROGEN CART STORED IN CONTROL ROOM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    143. MOBILE HIGH PRESSURE NITROGEN CART STORED IN CONTROL ROOM (214), LSB (BLDG. 751) - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  4. Free-grazing Ducks and Highly Pathogenic Avian Influenza, Thailand

    PubMed Central

    Chaitaweesub, Prasit; Parakamawongsa, Tippawon; Premashthira, Sith; Tiensin, Thanawat; Kalpravidh, Wantanee; Wagner, Hans; Slingenbergh, Jan

    2006-01-01

    Thailand has recently had 3 epidemic waves of highly pathogenic avian influenza (HPAI); virus was again detected in July 2005. Risk factors need to be identified to better understand disease ecology and assist HPAI surveillance and detection. This study analyzed the spatial distribution of HPAI outbreaks in relation to poultry, land use, and other anthropogenic variables from the start of the second epidemic wave (July 2004–May 2005). Results demonstrate a strong association between H5N1 virus in Thailand and abundance of free-grazing ducks and, to a lesser extent, native chickens, cocks, wetlands, and humans. Wetlands used for double-crop rice production, where free-grazing duck feed year round in rice paddies, appear to be a critical factor in HPAI persistence and spread. This finding could be important for other duck-producing regions in eastern and southeastern Asian countries affected by HPAI. PMID:16494747

  5. Highly Pathogenic Avian Influenza H5N1, Thailand, 2004

    PubMed Central

    Chaitaweesub, Prasit; Songserm, Thaweesak; Chaisingh, Arunee; Hoonsuwan, Wirongrong; Buranathai, Chantanee; Parakamawongsa, Tippawon; Premashthira, Sith; Amonsin, Alongkorn; Gilbert, Marius; Nielen, Mirjam; Stegeman, Arjan

    2005-01-01

    In January 2004, highly pathogenic avian influenza (HPAI) virus of the H5N1 subtype was first confirmed in poultry and humans in Thailand. Control measures, e.g., culling poultry flocks, restricting poultry movement, and improving hygiene, were implemented. Poultry populations in 1,417 villages in 60 of 76 provinces were affected in 2004. A total of 83% of infected flocks confirmed by laboratories were backyard chickens (56%) or ducks (27%). Outbreaks were concentrated in the Central, the southern part of the Northern, and Eastern Regions of Thailand, which are wetlands, water reservoirs, and dense poultry areas. More than 62 million birds were either killed by HPAI viruses or culled. H5N1 virus from poultry caused 17 human cases and 12 deaths in Thailand; a number of domestic cats, captive tigers, and leopards also died of the H5N1 virus. In 2005, the epidemic is ongoing in Thailand. PMID:16318716

  6. Horizontal gene acquisitions, mobile element proliferation, and genome decay in the host-restricted plant pathogen erwinia tracheiphila

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Modern industrial agriculture depends on high-density cultivation of genetically similar crop plants, creating favorable conditions for the emergence of novel pathogens with increased fitness in managed compared with ecologically intact settings. Here, we present the genome sequence of six strains o...

  7. Highly Pathogenic Avian Influenza Virus among Wild Birds in Mongolia

    PubMed Central

    Gilbert, Martin; Jambal, Losolmaa; Karesh, William B.; Fine, Amanda; Shiilegdamba, Enkhtuvshin; Dulam, Purevtseren; Sodnomdarjaa, Ruuragchaa; Ganzorig, Khuukhenbaatar; Batchuluun, Damdinjav; Tseveenmyadag, Natsagdorj; Bolortuya, Purevsuren; Cardona, Carol J.; Leung, Connie Y. H.; Peiris, J. S. Malik; Spackman, Erica; Swayne, David E.; Joly, Damien O.

    2012-01-01

    Mongolia combines a near absence of domestic poultry, with an abundance of migratory waterbirds, to create an ideal location to study the epidemiology of highly pathogenic avian influenza virus (HPAIV) in a purely wild bird system. Here we present the findings of active and passive surveillance for HPAIV subtype H5N1 in Mongolia from 2005–2011, together with the results of five outbreak investigations. In total eight HPAIV outbreaks were confirmed in Mongolia during this period. Of these, one was detected during active surveillance employed by this project, three by active surveillance performed by Mongolian government agencies, and four through passive surveillance. A further three outbreaks were recorded in the neighbouring Tyva Republic of Russia on a lake that bisects the international border. No HPAIV was isolated (cultured) from 7,855 environmental fecal samples (primarily from ducks), or from 2,765 live, clinically healthy birds captured during active surveillance (primarily shelducks, geese and swans), while four HPAIVs were isolated from 141 clinically ill or dead birds located through active surveillance. Two low pathogenic avian influenza viruses (LPAIV) were cultured from ill or dead birds during active surveillance, while environmental feces and live healthy birds yielded 56 and 1 LPAIV respectively. All Mongolian outbreaks occurred in 2005 and 2006 (clade 2.2), or 2009 and 2010 (clade 2.3.2.1); all years in which spring HPAIV outbreaks were reported in Tibet and/or Qinghai provinces in China. The occurrence of outbreaks in areas deficient in domestic poultry is strong evidence that wild birds can carry HPAIV over at least moderate distances. However, failure to detect further outbreaks of clade 2.2 after June 2006, and clade 2.3.2.1 after June 2010 suggests that wild birds migrating to and from Mongolia may not be competent as indefinite reservoirs of HPAIV, or that HPAIV did not reach susceptible populations during our study. PMID:22984464

  8. High carrier mobilities in black diamond

    NASA Astrophysics Data System (ADS)

    Williams, Oliver A.; Jackman, Richard B.; Nebel, Christoph; Foord, John S.

    2003-03-01

    Hydrogen plasma treatment of diamond renders the surface p-type, with the carriers emerging with little thermal activation, in sharp contrast to the use of boron for the formation of p-type material. To date, it has been thought that only the highest quality 'white' polycrystalline material is useful for electronic device applications, with many regarding single-crystal diamond as ultimately the substrate material of choice. In this paper it is shown that when p-type material is produced through hydrogenation, this is not the case. 'Black' polycrystalline diamond, which can be grown much more rapidly than white, shows carrier concentrations and mobility values similar to both white polycrystalline diamond and single-crystal material. This result has important implications for the provision of low-cost black-diamond substrates for device applications.

  9. Biological characteristics and pathogenicity of a highly pathogenic Shewanella marisflavi infected sea cucumber (Apostichopus uaponicus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Shewanella marisflavi isolate AP629 was characterized as a novel pathogen of sea cucumber. The LD50 values (14 days) in sea cucumber and swordtail fish were 3.89 × 106 and 4.85 × 104 CFU g-1 body weight, respectively. Studies on S. marisflavi had been conducted, including morphology, physiological a...

  10. New genomic characteristics of highly pathogenic porcine reproductive and respiratory syndrome viruses do not lead to significant changes in pathogenicity.

    PubMed

    Yu, Xiuling; Chen, Nanhua; Wang, Lilin; Wu, Jiajun; Zhou, Zhi; Ni, Jianqiang; Li, Xiangdong; Zhai, Xinyan; Shi, Jishu; Tian, Kegong

    2012-08-17

    Highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS) initially emerged in China and currently prevails in other Asian countries as well, resulting in immense economic losses. HP-PRRS virus (HP-PRRSV) has undergone rapid evolution since its first recognition in 2006. To analyze the genomic and pathogenic characteristics of 2010 HP-PRRSV, we tested 919 clinical samples collected from China, Laos and Vietnam, sequenced 29 complete genomes of HP-PRRSV isolates, and determined the pathogenicity of seven HP-PRRS viruses isolated from 2006 to 2010. HP-PRRSV was detected from 45.2% (415/919) samples, while only 0.1% (1/919) was classical PRRSV, indicating that HP-PRRSV isolates with a unique discontinuous deletion of 30 amino acids (aa) in non-structural protein 2 (Nsp2) are still the predominant viruses. 2010 HP-PRRSV together with 2009 HP-PRRSV isolates form a new evolutionary branch based on phylogenetic analyses. The numbers of potential N-glycosylation sites are variable in major glycoprotein GP5 but are conserved in minor glycoproteins GP2, GP3 and GP4. Pathogenicity studies showed that HP-PRRS viruses isolated from 2006 to 2010 maintain similar level of high pathogenicity, which caused high fever (>41°C for at least four days), 100% morbidity, and 40-100% mortality in 4-10 weeks old pigs. Real time monitoring information from this study could help to understand the genetic and pathogenic evolution of HP-PRRSV and assist in the control of HP-PRRS in Asia. PMID:22525010

  11. USGS role and response to highly pathogenic avian influenza

    USGS Publications Warehouse

    Harris, M. Camille; Miles, A. Keith; Pearce, John M.; Prosser, Diann J.; Sleeman, Jonathan M.; Whalen, Mary E.

    2015-01-01

    Avian influenza viruses are naturally occurring in wild birds such as ducks, geese, swans, and gulls. These viruses generally do not cause illness in wild birds, however, when spread to poultry they can be highly pathogenic and cause illness and death in backyard and commercial farms. Outbreaks may cause devastating agricultural economic losses and some viral strains have the potential to infect people directly. Furthermore, the combination of avian influenza viruses with mammalian viruses can result in strains with the ability to transmit from person to person, possibly leading to viruses with pandemic potential. All known pandemic influenza viruses have had some genetic material of avian origin. Since 1996, a strain of highly pathogenic avian influenza (HPAI) virus, H5N1, has caused infection in wild birds, losses to poultry farms in Eurasia and North Africa, and led to the deaths of several hundred people. Spread of the H5N1 virus and other influenza strains from China was likely facilitated by migratory birds. In December 2014, HPAI was detected in poultry in Canada and migratory birds in the United States. Since then, HPAI viruses have spread to large parts of the United States and will likely continue to spread through migratory bird flyways and other mechanisms throughout North America. In the United States, HPAI viruses have severely affected the poultry industry with millions of domestic birds dead or culled. These strains of HPAI are not known to cause disease in humans; however, the Centers for Disease Control and Prevention (CDC) advise caution when in close contact with infected birds. Experts agree that HPAI strains currently circulating in wild birds of North America will likely persist for the next few years. This unprecedented situation presents risks to the poultry industry, natural resource management, and potentially human health. Scientific knowledge and decision support tools are urgently needed to understand factors affecting the persistence

  12. Record high mobilities for regioregular poly(3-octylthiophene)

    NASA Astrophysics Data System (ADS)

    Sauvé, Geneviève; Liu, Junying; Zhang, Rui; Kowalewski, Tomasz; McCullough, Richard D.

    2007-09-01

    Regioregular poly(3-alkylthiophene)s are promising candidates for plastic electronics. In particular, poly(3- hexylthiophene) (P3HT) has attracted considerable interest due to its excellent field effect mobility. However, not much attention has been given to poly(3-alkylthiophene)s with longer alkyl side chains, mainly because a few studies reported that longer side chain length was detrimental to field effect mobility. However, these past studies used untreated SiO II as the gate dielectric and commercially available polymers synthesized by the Rieke method. Here, all polymers tested were synthesized in house using our quasi-living GRIM method to yield well-defined clean polymers. For our first study, we synthesized P3HT and regioregular poly(3-octylthiohene) (P3OT), both with a high molecular weight (Mn of 40kDa and 35kDa, respectively). Regioregular P3HT required some sonication to dissolve in chloroform, whereas P3OT dissolved readily in chloroform at room temperature. Hole mobility was measured using bottom-contact geometry, with SiO II as gate dielectric. The SiO II surface was either untreated, or chemically treated with octyltrichlorosilane. Average mobility on untreated SiO II was 0.09 cm2/Vs for P3HT and 0.03 cm2/Vs for P3OT. Average mobility on OTS-8 treated SiO II, on the other hand, was 0.13 cm2/Vs for P3HT and 0.19 cm2/Vs for P3OT. The OTS-8 treatment therefore dramatically improved the mobility of P3OT. Both polymers had a maximum mobility of about 0.2 cm2/Vs for channel lengths >=10 μm, and a mobility of 0.22 cm2/Vs was obtained several times for P3OT. To our knowledge, this is by far the highest mobility reported for P3OT.

  13. Characterization of the cell surface properties of drinking water pathogens by microbial adhesion to hydrocarbon and electrophoretic mobility measurements.

    PubMed

    Popovici, Jonathan; White, Colin P; Hoelle, Jill; Kinkle, Brian K; Lytle, Darren A

    2014-06-01

    The surface characteristics of microbial cells directly influence their mobility and behavior within aqueous environments. The cell surface hydrophobicity (CSH) and electrophoretic mobility (EPM) of microbial cells impact a number of interactions and processes including aggregation, adhesion to surfaces, and stability of the cells within the aqueous environments. These cell characteristics are unique to the bacterial species and are a reflection of the large diversity of surface structures, proteins, and appendages of microorganisms. CSH and EPM of bacterial cells contribute substantially to the effectiveness of drinking water treatment to remove them, and therefore an investigation of these properties will be useful in predicting their removal through drinking water treatment processes and transport through drinking water distribution systems. EPM and CSH measurements of six microbiological pathogen or surrogate species suspended in phosphate-buffered water are reported in this work. Two strains of Vibrio cholerae were hydrophobic, while three strains of Escherichia coli were hydrophilic. Bacillus cereus was categorized as moderately hydrophobic. The strains of E. coli had the highest (most negative) EPM. Based on the measurements, E. coli species is predicted to be most difficult to remove from water while V. cholerae will be the easiest to remove. PMID:24815929

  14. High prevalence of pathogenic Yersinia enterocolitica in pig cheeks.

    PubMed

    Laukkanen-Ninios, Riikka; Fredriksson-Ahomaa, Maria; Maijala, Riitta; Korkeala, Hannu

    2014-10-01

    Samples from pork cuts for minced meat and cheeks from processing plants and a slaughterhouse, and modified atmosphere (MA) packaged pork from retail were studied to estimate the prevalence of pathogenic, i.e. virulence plasmid bearing, Yersinia enterocolitica and Yersinia pseudotuberculosis in pork, as well as to quantify pathogenic Y. enterocolitica in pork cuts. Pathogenic (virF-positive) Y. enterocolitica was isolated from 17 pig cheeks (23%) but not from any of the MA-packaged 54 retail pork samples and only from one of the 155 pork cut (0.6%). Most (16/17) of the cheek samples were contaminated with pathogenic Y. enterocolitica 4/O:3 and one with bioserotype 2/O:9. No Y. pseudotuberculosis was isolated. The prevalence of pathogenic Y. enterocolitica was clearly higher (39%) in 155 pork cuts when studied with nested PCR targeting yadA on the virulence plasmid pYV although the contamination level was low varying between 0.1 and 1.6 MPN/g. Raw pork cuts and especially pig cheeks may serve as possible sources for yersiniosis caused by pathogenic Y. enterocolitica. PMID:24929882

  15. High doses of highly pathogenic avian influenza virus in chicken meat are required to infect ferrets

    Technology Transfer Automated Retrieval System (TEKTRAN)

    H5N1 high pathogenicity avian influenza viruses (HPAIV) have caused natural and experimental infections in various animals through consumption of infected bird carcasses and meat. However, little is known about the quantity of virus required and if all HPAIV subtypes can cause infections following c...

  16. Highly pathogenic porcine reproductive and respiratory syndrome virus JXwn06 causes high mortality in vivo

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2006, a large-scale outbreak of highly pathogenic atypical porcine reproductive and respiratory syndrome virus (PRRSV) spread throughout the swine population in China. Causative PRRSV isolates were characterized genetically by a unique 30aa deletion in PRRSV nonstructural protein 2 and clinically...

  17. High Mobility Two-Dimensional Electron Gas in Black Phosphorus

    NASA Astrophysics Data System (ADS)

    Li, Likai; Ye, Guojun; Tran, Vy; Chen, Guorui; Wang, Huichao; Wang, Jian; Watanabe, Kenji; Taniguchi, Takashi; Yang, Li; Chen, Xianhui; Zhang, Yuanbo

    2015-03-01

    Black phosphorus has recently emerged as a new member in the family of two-dimensional (2D) atomic crystals. It is a semiconductor with a tunable bandgap and high carrier mobility - material properties that are important for potential opto-electronic and high-speed device applications. In this work, we achieve a record-high carrier mobility in black phosphorus by placing it on hexagonal boron nitride (h-BN) substrate. The exceptional mobility of the 2D electron gas created at the interface allows us to observe quantum oscillations for the first time in this material. The temperature and magnetic field dependence of the oscillations yields crucial information about the black phosphorus 2DEG, such as cyclotron mass of the charge carriers and their lifetime. Our results pave the way to future research on quantum transport in black phosphorus.

  18. Evolutionary Dynamics of a Highly Pathogenic Type 2 Porcine Reproductive and Respiratory Syndrome Virus: Analyses of Envelope Protein-Coding Genes.

    PubMed

    Nguyen, V G; Kim, H K; Moon, H J; Park, S J; Chung, H C; Choi, M K; Park, B K

    2015-08-01

    Porcine reproductive and respiratory syndrome virus (PRRSV) has long been an economically devastating swine viral disease. The recent emergence of a highly pathogenic type 2 PRRSV with high mobility and mortality in China, spreading in Vietnam, Laos, and Thailand has placed neighbouring countries at risk. This study applied a codon-based extension of the Bayesian relaxed clock model and the fixed effects maximum-likelihood method to investigate and compare the evolutionary dynamics of type 2 PRRSV for all of known structural envelope protein-coding genes. By comparing the highly pathogenic type 2 PRRSV clade against the typical type 2 PRRSV clade, this study demonstrated that the highly pathogenic clade evolved at high rates in all of the known structural genes but did not display rapid evolutionary dynamics compared with typical type 2 PRRSV. In contrast, the ORF3, ORF5 and ORF6 genes of the highly pathogenic clade evolved in a qualitatively different manner from the genes of the typical clade. At the population level, several codons of the sequence elements that were involved in viral neutralization, as well as codons that were associated with in vitro attenuation/over-attenuation, were predicted to be selected differentially between the typical clade and the highly pathogenic clade. The results of this study suggest that the multigenic factors of the envelope protein-coding genes contribute to diversifying the biological properties (virulence, antigenicity, etc.) of the highly pathogenic clade compared with the typical clade of type 2 PRRSV. PMID:23981823

  19. Control strategies for highly pathogenic avian influenza: a global perspective.

    PubMed

    Lubroth, J

    2007-01-01

    Comprehensive programmes for the prevention, detection and control of highly pathogenic avian influenza (HPAI) require a national dimension and relevant national legislation in which veterinary services can conduct surveillance, competent diagnosis and rapid response. Avian influenza was controlled and prevented by vaccination long before the current H5N1 crisis. The use of vaccine cannot be separated from other essential elements of a vaccination campaign, which include education in poultry production practices, such as hygiene, all in-all out production concepts, separation of species, biosecurity (bio-exclusion to keep the disease out and biocontainment to keep the disease from spreading once suspected or detected), competence in giving the vaccine and the role of vaccination teams, post-vaccination monitoring to ensure efficacy and to detect the circulation of wild-type virus, surveillance and buffer zones in outbreak areas, and performance indicators to determine when vaccination can cease. Reporting of disease can be improved through well-structured, adequately financed veterinary services and also by fair compensation for producers who suffer financial loss. A rapid response to suspected cases of HPAI should be ensured in simulation exercises involving various sectors of the food production and marketing chain, policy-makers, official veterinary structures and other government personnel. As for other transboundary animal diseases, national approaches must be part of a regional strategy and regional networks for cooperation and information sharing, which in turn reflect global policies and international standards, such as the quality of vaccines, reporting obligations, humane interventions, cleaning and disinfection methods, restocking times, monitoring and safe trade. PMID:18411931

  20. Extremely high electron mobility in a phonon-glass semimetal.

    PubMed

    Ishiwata, S; Shiomi, Y; Lee, J S; Bahramy, M S; Suzuki, T; Uchida, M; Arita, R; Taguchi, Y; Tokura, Y

    2013-06-01

    The electron mobility is one of the key parameters that characterize the charge-carrier transport properties of materials, as exemplified by the quantum Hall effect as well as high-efficiency thermoelectric and solar energy conversions. For thermoelectric applications, introduction of chemical disorder is an important strategy for reducing the phonon-mediated thermal conduction, but is usually accompanied by mobility degradation. Here, we show a multilayered semimetal β-CuAgSe overcoming such a trade-off between disorder and mobility. The polycrystalline ingot shows a giant positive magnetoresistance and Shubnikov de Haas oscillations, indicative of a high-mobility small electron pocket derived from the Ag s-electron band. Ni doping, which introduces chemical and lattice disorder, further enhances the electron mobility up to 90,000 cm(2) V(-1) s(-1) at 10 K, leading not only to a larger magnetoresistance but also a better thermoelectric figure of merit. This Ag-based layered semimetal with a glassy lattice is a new type of promising thermoelectric material suitable for chemical engineering. PMID:23603851

  1. Increased virulence in ducks of H5N1 highly pathogenic avian influenza viruses from Egypt

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The pathogenicity of H5N1 highly pathogenic avian influenza (HPAI) viruses in domestic ducks has increased over time. These changes in virulence have been reported with viruses from countries with high population of domestic ducks. Since 2006, H5N1 HPAI outbreaks in Egypt have been occurring in po...

  2. Rapid and Accurate Detection of Urinary Pathogens by Mobile IMS-Based Electronic Nose: A Proof-of-Principle Study

    PubMed Central

    Roine, Antti; Saviauk, Taavi; Kumpulainen, Pekka; Karjalainen, Markus; Tuokko, Antti; Aittoniemi, Janne; Vuento, Risto; Lekkala, Jukka; Lehtimäki, Terho; Tammela, Teuvo L.; Oksala, Niku K. J.

    2014-01-01

    Urinary tract infection (UTI) is a common disease with significant morbidity and economic burden, accounting for a significant part of the workload in clinical microbiology laboratories. Current clinical chemisty point-of-care diagnostics rely on imperfect dipstick analysis which only provides indirect and insensitive evidence of urinary bacterial pathogens. An electronic nose (eNose) is a handheld device mimicking mammalian olfaction that potentially offers affordable and rapid analysis of samples without preparation at athmospheric pressure. In this study we demonstrate the applicability of ion mobility spectrometry (IMS) –based eNose to discriminate the most common UTI pathogens from gaseous headspace of culture plates rapidly and without sample preparation. We gathered a total of 101 culture samples containing four most common UTI bacteries: E. coli, S. saprophyticus, E. faecalis, Klebsiella spp and sterile culture plates. The samples were analyzed using ChemPro 100i device, consisting of IMS cell and six semiconductor sensors. Data analysis was conducted by linear discriminant analysis (LDA) and logistic regression (LR). The results were validated by leave-one-out and 5-fold cross validation analysis. In discrimination of sterile and bacterial samples sensitivity of 95% and specificity of 97% were achieved. The bacterial species were identified with sensitivity of 95% and specificity of 96% using eNose as compared to urine bacterial cultures. In conclusion: These findings strongly demonstrate the ability of our eNose to discriminate bacterial cultures and provides a proof of principle to use this method in urinanalysis of UTI. PMID:25526592

  3. Rapid and High-Throughput Detection of Highly Pathogenic Bacteria by Ibis PLEX-ID Technology

    PubMed Central

    Jacob, Daniela; Sauer, Uschi; Housley, Roberta; Washington, Cicely; Sannes-Lowery, Kristin; Ecker, David J.; Sampath, Rangarajan; Grunow, Roland

    2012-01-01

    In this manuscript, we describe the identification of highly pathogenic bacteria using an assay coupling biothreat group-specific PCR with electrospray ionization mass spectrometry (PCR/ESI-MS) run on an Ibis PLEX-ID high-throughput platform. The biothreat cluster assay identifies most of the potential bioterrorism-relevant microorganisms including Bacillus anthracis, Francisella tularensis, Yersinia pestis, Burkholderia mallei and pseudomallei, Brucella species, and Coxiella burnetii. DNA from 45 different reference materials with different formulations and different concentrations were chosen and sent to a service screening laboratory that uses the PCR/ESI-MS platform to provide a microbial identification service. The standard reference materials were produced out of a repository built up in the framework of the EU funded project “Establishment of Quality Assurances for Detection of Highly Pathogenic Bacteria of Potential Bioterrorism Risk” (EQADeBa). All samples were correctly identified at least to the genus level. PMID:22768173

  4. High-Throughput Microfluidic Method To Study Biofilm Formation and Host-Pathogen Interactions in Pathogenic Escherichia coli

    PubMed Central

    Tremblay, Yannick D. N.; Vogeleer, Philippe; Jacques, Mario

    2015-01-01

    Biofilm formation and host-pathogen interactions are frequently studied using multiwell plates; however, these closed systems lack shear force, which is present at several sites in the host, such as the intestinal and urinary tracts. Recently, microfluidic systems that incorporate shear force and very small volumes have been developed to provide cell biology models that resemble in vivo conditions. Therefore, the objective of this study was to determine if the BioFlux 200 microfluidic system could be used to study host-pathogen interactions and biofilm formation by pathogenic Escherichia coli. Strains of various pathotypes were selected to establish the growth conditions for the formation of biofilms in the BioFlux 200 system on abiotic (glass) or biotic (eukaryotic-cell) surfaces. Biofilm formation on glass was observed for the majority of strains when they were grown in M9 medium at 30°C but not in RPMI medium at 37°C. In contrast, HRT-18 cell monolayers enhanced binding and, in most cases, biofilm formation by pathogenic E. coli in RPMI medium at 37°C. As a proof of principle, the biofilm-forming ability of a diffusely adherent E. coli mutant strain lacking AIDA-I, a known mediator of attachment, was assessed in our models. In contrast to the parental strain, which formed a strong biofilm, the mutant formed a thin biofilm on glass or isolated clusters on HRT-18 monolayers. In conclusion, we describe a microfluidic method for high-throughput screening that could be used to identify novel factors involved in E. coli biofilm formation and host-pathogen interactions under shear force. PMID:25681176

  5. Engineered nanoconstructs for the multiplexed and sensitive detection of high-risk pathogens.

    PubMed

    Seo, Youngmin; Kim, Ji-eun; Jeong, Yoon; Lee, Kwan Hong; Hwang, Jangsun; Hong, Jongwook; Park, Hansoo; Choi, Jonghoon

    2016-01-28

    Many countries categorize the causative agents of severe infectious diseases as high-risk pathogens. Given their extreme infectivity and potential to be used as biological weapons, a rapid and sensitive method for detection of high-risk pathogens (e.g., Bacillus anthracis, Francisella tularensis, Yersinia pestis, and Vaccinia virus) is highly desirable. Here, we report the construction of a novel detection platform comprising two units: (1) magnetic beads separately conjugated with multiple capturing antibodies against four different high-risk pathogens for simple and rapid isolation, and (2) genetically engineered apoferritin nanoparticles conjugated with multiple quantum dots and detection antibodies against four different high-risk pathogens for signal amplification. For each high-risk pathogen, we demonstrated at least 10-fold increase in sensitivity compared to traditional lateral flow devices that utilize enzyme-based detection methods. Multiplexed detection of high-risk pathogens in a sample was also successful by using the nanoconstructs harboring the dye molecules with fluorescence at different wavelengths. We ultimately envision the use of this novel nanoprobe detection platform in future applications that require highly sensitive on-site detection of high-risk pathogens. PMID:26462853

  6. Engineered nanoconstructs for the multiplexed and sensitive detection of high-risk pathogens

    NASA Astrophysics Data System (ADS)

    Seo, Youngmin; Kim, Ji-Eun; Jeong, Yoon; Lee, Kwan Hong; Hwang, Jangsun; Hong, Jongwook; Park, Hansoo; Choi, Jonghoon

    2016-01-01

    Many countries categorize the causative agents of severe infectious diseases as high-risk pathogens. Given their extreme infectivity and potential to be used as biological weapons, a rapid and sensitive method for detection of high-risk pathogens (e.g., Bacillus anthracis, Francisella tularensis, Yersinia pestis, and Vaccinia virus) is highly desirable. Here, we report the construction of a novel detection platform comprising two units: (1) magnetic beads separately conjugated with multiple capturing antibodies against four different high-risk pathogens for simple and rapid isolation, and (2) genetically engineered apoferritin nanoparticles conjugated with multiple quantum dots and detection antibodies against four different high-risk pathogens for signal amplification. For each high-risk pathogen, we demonstrated at least 10-fold increase in sensitivity compared to traditional lateral flow devices that utilize enzyme-based detection methods. Multiplexed detection of high-risk pathogens in a sample was also successful by using the nanoconstructs harboring the dye molecules with fluorescence at different wavelengths. We ultimately envision the use of this novel nanoprobe detection platform in future applications that require highly sensitive on-site detection of high-risk pathogens.

  7. High mobility solution-processed hybrid light emitting transistors

    NASA Astrophysics Data System (ADS)

    Walker, Bright; Ullah, Mujeeb; Chae, Gil Jo; Burn, Paul L.; Cho, Shinuk; Kim, Jin Young; Namdas, Ebinazar B.; Seo, Jung Hwa

    2014-11-01

    We report the design, fabrication, and characterization of high-performance, solution-processed hybrid (inorganic-organic) light emitting transistors (HLETs). The devices employ a high-mobility, solution-processed cadmium sulfide layer as the switching and transport layer, with a conjugated polymer Super Yellow as an emissive material in non-planar source/drain transistor geometry. We demonstrate HLETs with electron mobilities of up to 19.5 cm2/V s, current on/off ratios of >107, and external quantum efficiency of 10-2% at 2100 cd/m2. These combined optical and electrical performance exceed those reported to date for HLETs. Furthermore, we provide full analysis of charge injection, charge transport, and recombination mechanism of the HLETs. The high brightness coupled with a high on/off ratio and low-cost solution processing makes this type of hybrid device attractive from a manufacturing perspective.

  8. High mobility solution-processed hybrid light emitting transistors

    SciTech Connect

    Walker, Bright; Kim, Jin Young; Ullah, Mujeeb; Burn, Paul L.; Namdas, Ebinazar B. E-mail: seojh@dau.ac.kr; Chae, Gil Jo; Cho, Shinuk; Seo, Jung Hwa E-mail: seojh@dau.ac.kr

    2014-11-03

    We report the design, fabrication, and characterization of high-performance, solution-processed hybrid (inorganic-organic) light emitting transistors (HLETs). The devices employ a high-mobility, solution-processed cadmium sulfide layer as the switching and transport layer, with a conjugated polymer Super Yellow as an emissive material in non-planar source/drain transistor geometry. We demonstrate HLETs with electron mobilities of up to 19.5 cm{sup 2}/V s, current on/off ratios of >10{sup 7}, and external quantum efficiency of 10{sup −2}% at 2100 cd/m{sup 2}. These combined optical and electrical performance exceed those reported to date for HLETs. Furthermore, we provide full analysis of charge injection, charge transport, and recombination mechanism of the HLETs. The high brightness coupled with a high on/off ratio and low-cost solution processing makes this type of hybrid device attractive from a manufacturing perspective.

  9. Plasmon dispersions in high electron mobility terahertz detectors

    SciTech Connect

    Białek, M. Łusakowski, J.; Czapkiewicz, M.; Umansky, V.

    2014-06-30

    Low temperature, high magnetic field experiments were carried out with monochromatic terahertz (THz) sources to reveal multimode spectra of magnetoplasmons excited in gated and ungated samples processed on a high electron mobility GaAs/AlGaAs heterostructure. We show that playing with the geometry and thickness of the gate one can control both the plasmon dispersion relation and selection rules for plasmon excitation, giving a tool to a better control of plasmon resonances in THz detectors.

  10. Highly Pathogenic New World and Old World Human Arenaviruses Induce Distinct Interferon Responses in Human Cells

    PubMed Central

    Huang, Cheng; Kolokoltsova, Olga A.; Yun, Nadezhda E.; Seregin, Alexey V.; Ronca, Shannon; Koma, Takaaki

    2015-01-01

    ABSTRACT The arenavirus family includes several important pathogens that cause severe and sometimes fatal diseases in humans. The highly pathogenic Old World (OW) arenavirus Lassa fever virus (LASV) is the causative agent of Lassa fever (LF) disease in humans. LASV infections in severe cases are generally immunosuppressive without stimulating interferon (IFN) induction, a proinflammatory response, or T cell activation. However, the host innate immune responses to highly pathogenic New World (NW) arenaviruses are not well understood. We have previously shown that the highly pathogenic NW arenavirus, Junin virus (JUNV), induced an IFN response in human A549 cells. Here, we report that Machupo virus (MACV), another highly pathogenic NW arenavirus, also induces an IFN response. Importantly, both pathogenic NW arenaviruses, in contrast to the OW highly pathogenic arenavirus LASV, readily elicited an IFN response in human primary dendritic cells and A549 cells. Coinfection experiments revealed that LASV could potently inhibit MACV-activated IFN responses even at 6 h after MACV infection, while the replication levels of MACV and LASV were not affected by virus coinfection. Our results clearly demonstrated that although all viruses studied herein are highly pathogenic to humans, the host IFN responses toward infections with the NW arenaviruses JUNV and MACV are quite different from responses to infections with the OW arenavirus LASV, a discovery that needs to be further investigated in relevant animal models. This finding might help us better understand various interplays between the host immune system and highly pathogenic arenaviruses as well as distinct mechanisms underlying viral pathogenesis. IMPORTANCE Infections of humans with the highly pathogenic OW LASV are accompanied by potent suppression of interferon or proinflammatory cytokine production. In contrast, infections with the highly pathogenic NW arenavirus JUNV are associated with high levels of IFNs and

  11. Reduced Set of Virulence Genes Allows High Accuracy Prediction of Bacterial Pathogenicity in Humans

    PubMed Central

    Iraola, Gregorio; Vazquez, Gustavo; Spangenberg, Lucía; Naya, Hugo

    2012-01-01

    Although there have been great advances in understanding bacterial pathogenesis, there is still a lack of integrative information about what makes a bacterium a human pathogen. The advent of high-throughput sequencing technologies has dramatically increased the amount of completed bacterial genomes, for both known human pathogenic and non-pathogenic strains; this information is now available to investigate genetic features that determine pathogenic phenotypes in bacteria. In this work we determined presence/absence patterns of different virulence-related genes among more than finished bacterial genomes from both human pathogenic and non-pathogenic strains, belonging to different taxonomic groups (i.e: Actinobacteria, Gammaproteobacteria, Firmicutes, etc.). An accuracy of 95% using a cross-fold validation scheme with in-fold feature selection is obtained when classifying human pathogens and non-pathogens. A reduced subset of highly informative genes () is presented and applied to an external validation set. The statistical model was implemented in the BacFier v1.0 software (freely available at ), that displays not only the prediction (pathogen/non-pathogen) and an associated probability for pathogenicity, but also the presence/absence vector for the analyzed genes, so it is possible to decipher the subset of virulence genes responsible for the classification on the analyzed genome. Furthermore, we discuss the biological relevance for bacterial pathogenesis of the core set of genes, corresponding to eight functional categories, all with evident and documented association with the phenotypes of interest. Also, we analyze which functional categories of virulence genes were more distinctive for pathogenicity in each taxonomic group, which seems to be a completely new kind of information and could lead to important evolutionary conclusions. PMID:22916122

  12. Helping poultry and people through research on high pathogenicity avian influenza

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza (AI) viruses are a diverse group divided into 144 different subtypes based on different combinations of the 16 hemagglutinin and 9 neuraminidase subtypes, and two different pathotypes (low [LP] and high pathogenicity [HP]). Low pathogenicity avian influenza (LPAI) viruses are maintai...

  13. Pathogenicity comparison of high and low virulent strains of Vibrio scophthalmi in olive flounder (Paralichthys olivaceus)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vibrio scophthalmi is a bacterial pathogen of olive flounder (Paralichthys olivaceus) and virulence is different from various strains. There is not information available on pathogenicity to olive flounder caused by different strains of V. scophthalmi. In this study, the high and low virulent strains...

  14. SAP102 is a highly mobile MAGUK in spines

    PubMed Central

    Zheng, Chan-Ying; Petralia, Ronald S.; Wang, Ya-Xian; Kachar, Bechara; Wenthold, Robert J.

    2010-01-01

    Membrane associated guanylate kinases (MAGUKs), which are essential proteins in the postsynaptic density (PSD), cluster and anchor glutamate receptors and other proteins at synapses. The MAGUK family includes PSD-95, PSD-93, SAP102, and SAP97. Individual family members can compensate for one another in their ability to recruit and retain receptors at the postsynaptic membrane as shown through deletion and knockdown studies. SAP102 is highly expressed in both young and mature neurons, however, little is known about its localization and mobility at synapses. Here, we compared the distribution, mobility, and turnover times of SAP102 to the well-studied MAGUK, PSD-95. Using light and electron microscopy, we found that SAP102 shows a broader distribution as well as peak localization further away from the postsynaptic membrane than PSD-95. Using fluorescence recovery after photobleaching (FRAP), we found that 80% of SAP102 and 36% of PSD-95 are mobile in spines. Previous studies showed that PSD-95 was stabilized at the PSD by N-terminal palmitoylation. We found that stabilization of SAP102 at the PSD was dependent on its SH3/GK domains but not its PDZ interactions. Furthermore, we showed that stabilizing actin or blocking NMDA/AMPA receptors reduced the mobile pool of SAP102 but did not affect the mobile pool of PSD-95. Our results show significant differences in the localization, binding mechanism, and mobility of SAP102 and PSD-95. These differences and the compensatory properties of the MAGUKs point out an unrecognized versatility of the MAGUKs in their function in synaptic organization and plasticity. PMID:20357126

  15. High mobility ZnO nanowires for terahertz detection applications

    NASA Astrophysics Data System (ADS)

    Liu, Huiqiang; Peng, Rufang; Chu, Sheng; Chu, Shijin

    2014-07-01

    An oxide nanowire material was utilized for terahertz detection purpose. High quality ZnO nanowires were synthesized and field-effect transistors were fabricated. Electrical transport measurements demonstrated the nanowire with good transfer characteristics and fairly high electron mobility. It is shown that ZnO nanowires can be used as building blocks for the realization of terahertz detectors based on a one-dimensional plasmon detection configuration. Clear terahertz wave (˜0.3 THz) induced photovoltages were obtained at room temperature with varying incidence intensities. Further analysis showed that the terahertz photoresponse is closely related to the high electron mobility of the ZnO nanowire sample, which suggests that oxide nanoelectronics may find useful terahertz applications.

  16. Pathogenicity of the Korean H5N8 highly pathogenic avian influenza virus in commercial domestic poultry species.

    PubMed

    Lee, Dong-Hun; Kwon, Jung-Hoon; Noh, Jin-Yong; Park, Jae-Keun; Yuk, Seong-Su; Erdene-Ochir, Tseren-Ochir; Lee, Joong-Bok; Park, Seung-Yong; Choi, In-Soo; Lee, Sang-Won; Song, Chang-Seon

    2016-01-01

    In 2014, the highly pathogenic avian influenza (HPAI) virus H5N8 triggered outbreaks in wild birds and poultry farms in South Korea. In the present study, we investigated the pathogenicity of the H5N8 HPAI virus, belonging to the clade 2.3.4.4, in different species of poultry. For this, we examined clinical signs and viral shedding levels following intranasal inoculation of the virus in 3-week-old commercial layer chickens and quails, 10-week-old Korean native chickens, and 8-week-old Muscovy ducks. Intranasal inoculation with 10(6.0) viruses at 50% egg-infective dose resulted in 100% mortality in the layer chickens (8/8) and quails (4/4), but 60% and 0% deaths in the Korean native chickens (3/5) and Muscovy ducks (0/4), respectively. In addition, transmission of the inoculated virus to contact-exposed birds was evident in all the species used in this study. Based on our results, we conclude that the H5N8 HPAI virus has lower pathogenicity and transmissibility in poultry species compared with previously reported H5N1 HPAI viruses. PMID:26814367

  17. A wideband propagation simulator for high speed mobile radio communications

    NASA Astrophysics Data System (ADS)

    Busson, P.; Lejannic, J. C.; Elzein, G.; Citerne, J.

    1994-07-01

    Multipath, jamming, listening and detection are the main limitations for mobile radio communications. Spread spectrum techniques, especially frequency hopping, can be used to avoid these problems. Therefore, a wideband simulation for multipath mobile channels appeared the most appropriate evaluation technique. It also gives useful indications for system characteristic improvements. This paper presents the design and realization of a new UHF-VHF propagation simulator, which can be considered as an extended version of Bussgang's one. This frequency hopping simulator (up to 100,000 hops per second) is wideband thus capable to deal with spread spectrum signals. As it generates up to 16 paths, it can be used in almost all mobile radio propagation situations. Moreover, it is also able to simulate high mobile relative speeds up to 2000km/h such as air-air communication systems. This simulator can reproduce, in laboratory, 16 rays Rician or Rayleigh fading channels with a maximum time delay of about 15 ms. At the highest frequency of 1200 MHz, Doppler rates up to 2 kHz can be generated corresponding to vehicle speeds up to 2000 km/h. Let note that the Bussgang simulator was defined for narrowband and fixed radio communications. In both equipments, in-phase and quadrature signals are obtained using two numerical transversal filters. Simulation results were derived in various situations especially in terrestrial urban and suburban environments, where they could be compared with measurements. The main advantage of the simulator lies in its capacity to simulate the high speed and wideband mobile radio communication channels.

  18. Electrophoresis system for high temperature mobility measurements of nanosize particles

    NASA Astrophysics Data System (ADS)

    Rodriguez-Santiago, Victor; Fedkin, Mark V.; Lvov, Serguei N.

    2008-09-01

    The electrophoretic mobility, which reflects the zeta potential of a solid material, is an important experimental quantity providing information about the electrical double layer at the solid/liquid interface. A new high temperature electrophoresis cell was developed suitable for electrophoretic mobility measurements of dispersed nanosize particles up to 150 °C and 40 bars. Amorphous silica (SiO2) particle size standards were used to test the particle size detection limit of the new instrument at 25, 100, and 150 °C and several pH values. The microscopic detection of the particles was enabled by dark-field illumination, which allowed extending the previously available capabilities and provided higher accuracy of the electrophoretic mobility data. The electrophoretic mobility measurements for SiO2 at temperatures above 100 °C were reported for the first time and indicated a gradual increase in particle electrophoretic response with increasing temperature. The obtained data indicated negatively charged SiO2 surface throughout the pH and temperature ranges studied.

  19. Glasslike Heat Conduction in High-Mobility Crystalline Semiconductors

    NASA Astrophysics Data System (ADS)

    Cohn, J. L.; Nolas, G. S.; Fessatidis, V.; Metcalf, T. H.; Slack, G. A.

    1999-01-01

    The thermal conductivity of polycrystalline semiconductors with type-I clathrate hydrate crystal structure is reported. Ge clathrates (doped with Sr and/or Eu) exhibit lattice thermal conductivities typical of amorphous materials. Remarkably, this behavior occurs in spite of the well-defined crystalline structure and relatively high electron mobility ( ~100 cm2/V s). The dynamics of dopant ions and their interaction with the polyhedral cages of the structure are a likely source of the strong phonon scattering.

  20. New resistivity for high-mobility quantum Hall conductors

    NASA Technical Reports Server (NTRS)

    Mceuen, P. L.; Szafer, A.; Richter, C. A.; Alphenaar, B. W.; Jain, J. K.

    1990-01-01

    Measurements showing dramatic nonlocal behavior in the four-terminal resistances of a high-mobility quantum Hall conductor are presented. These measurements illustrate that the standard definition of the resistivity tensor is inappropriate, but they are in excellent agreement with a new model of the conductor that treats the edge and bulk conducting pathways independently. This model uses a single intensive parameter, analogous to a local resistivity for the bulk channel only, to characterize the system.

  1. Ultimate response time of high electron mobility transistors

    SciTech Connect

    Rudin, Sergey; Rupper, Greg; Shur, Michael

    2015-05-07

    We present theoretical studies of the response time of the two-dimensional gated electron gas to femtosecond pulses. Our hydrodynamic simulations show that the device response to a short pulse or a step-function signal is either smooth or oscillating time-decay at low and high mobility, μ, values, respectively. At small gate voltage swings, U{sub 0} = U{sub g} − U{sub th}, where U{sub g} is the gate voltage and U{sub th} is the threshold voltage, such that μU{sub 0}/L < v{sub s}, where L is the channel length and v{sub s} is the effective electron saturation velocity, the decay time in the low mobility samples is on the order of L{sup 2}/(μU{sub 0}), in agreement with the analytical drift model. However, the decay is preceded by a delay time on the order of L/s, where s is the plasma wave velocity. This delay is the ballistic transport signature in collision-dominated devices, which becomes important during very short time periods. In the high mobility devices, the period of the decaying oscillations is on the order of the plasma wave velocity transit time. Our analysis shows that short channel field effect transistors operating in the plasmonic regime can meet the requirements for applications as terahertz detectors, mixers, delay lines, and phase shifters in ultra high-speed wireless communication circuits.

  2. Temperature dependence of ballistic mobility in a metamorphic InGaAs/InAlAs high electron mobility transistor

    SciTech Connect

    Lee, Jongkyong; Gang, Suhyun; Jo, Yongcheol; Kim, Jongmin; Woo, Hyeonseok; Han, Jaeseok; Kim, Hyungsang Im, Hyunsik

    2014-07-28

    We have investigated the temperature dependence of ballistic mobility in a 100 nm-long InGaAs/InAlAs metamorphic high-electron-mobility transistor designed for millimeter-wavelength RF applications. To extract the temperature dependence of quasi-ballistic mobility, our experiment involves measurements of the effective mobility in the low-bias linear region of the transistor and of the collision-dominated Hall mobility using a gated Hall bar of the same epitaxial structure. The data measured from the experiment are consistent with that of modeled ballistic mobility based on ballistic transport theory. These results advance the understanding of ballistic transport in various transistors with a nano-scale channel length that is comparable to the carrier's mean free path in the channel.

  3. Characterization of the Cell Surface Properties of Drinking Water Pathogens by Microbial Adhesion to Hydrocarbon and Electrophoretic Mobility Measurements

    EPA Science Inventory

    The surface characteristics of microbial cells directly influence their mobility and behavior within aqueous environments. The cell surface hydrophobicity (CSH) and electrophoretic mobility (EPM) of microbial cells impact a number of interactions and processes including aggregati...

  4. The role of C5a in acute lung injury induced by highly pathogenic viral infections

    PubMed Central

    Wang, Renxi; Xiao, He; Guo, Renfeng; Li, Yan; Shen, Beifen

    2015-01-01

    The complement system, an important part of innate immunity, plays a critical role in pathogen clearance. Unregulated complement activation is likely to play a crucial role in the pathogenesis of acute lung injury (ALI) induced by highly pathogenic virus including influenza A viruses H5N1, H7N9, and severe acute respiratory syndrome (SARS) coronavirus. In highly pathogenic virus-induced acute lung diseases, high levels of chemotactic and anaphylatoxic C5a were produced as a result of excessive complement activaiton. Overproduced C5a displays powerful biological activities in activation of phagocytic cells, generation of oxidants, and inflammatory sequelae named “cytokine storm”, and so on. Blockade of C5a signaling have been implicated in the treatment of ALI induced by highly pathogenic virus. Herein, we review the literature that links C5a and ALI, and review our understanding of the mechanisms by which C5a affects ALI during highly pathogenic viral infection. In particular, we discuss the potential of the blockade of C5a signaling to treat ALI induced by highly pathogenic viruses. PMID:26060601

  5. Outbreak of H7N8 Low Pathogenic Avian Influenza in Commercial Turkeys with Spontaneous Mutation to Highly Pathogenic Avian Influenza.

    PubMed

    Killian, Mary Lea; Kim-Torchetti, Mia; Hines, Nichole; Yingst, Sam; DeLiberto, Thomas; Lee, Dong-Hun

    2016-01-01

    Highly pathogenic avian influenza (HPAI) subtype H7N8 was detected in commercial turkeys in January 2016. Control zone surveillance discovered a progenitor low pathogenic avian influenza (LPAI) virus in surrounding turkey flocks. Data analysis supports a single LPAI virus introduction followed by spontaneous mutation to HPAI on a single premises. PMID:27313288

  6. Outbreak of H7N8 Low Pathogenic Avian Influenza in Commercial Turkeys with Spontaneous Mutation to Highly Pathogenic Avian Influenza

    PubMed Central

    Killian, Mary Lea; Hines, Nichole; Yingst, Sam; DeLiberto, Thomas; Lee, Dong-Hun

    2016-01-01

    Highly pathogenic avian influenza (HPAI) subtype H7N8 was detected in commercial turkeys in January 2016. Control zone surveillance discovered a progenitor low pathogenic avian influenza (LPAI) virus in surrounding turkey flocks. Data analysis supports a single LPAI virus introduction followed by spontaneous mutation to HPAI on a single premises. PMID:27313288

  7. Variation in infectivity and adaptation of wild duck- and poultry-origin high pathogenicity and low pathogenicity avian influenza viruses for poultry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza (AI) viruses vary in their adaptation which impacts transmission between and infection of different bird species. We determine the intranasal mean bird infectious doses (BID50) for 11 high pathogenicity (HP) AI viruses for layer type chickens (LC), and three low pathogenicity (LP) A...

  8. Correlating Questionnaire Data with Actual Usage Data in a Mobile Learning Study for High School Mathematics

    ERIC Educational Resources Information Center

    Kalloo, Vani; Mohan, Permanand

    2012-01-01

    A mobile learning research project was conducted in Trinidad and Tobago to determine if mobile learning can assist high school students in learning mathematics. Several innovative techniques were used in this research to address the problem of high failure rates of mathematics in high schools in the Caribbean. A mobile learning application was…

  9. Accelerated High-Resolution Differential Ion Mobility Separations Using Hydrogen

    PubMed Central

    Shvartsburg, Alexandre A.; Smith, Richard D.

    2011-01-01

    The resolving power of differential ion mobility spectrometry (FAIMS) was dramatically increased recently by carrier gases comprising up to 75% He or various vapors, enabling many new applications. However, the need for resolution of complex mixtures is virtually open-ended and many topical analyses demand yet finer separations. Also, the resolving power gains are often at the expense of speed, in particular making high-resolution FAIMS incompatible with online liquid-phase separations. Here, we report FAIMS employing hydrogen, specifically in mixtures with N2 containing up to 90% H2. Such compositions raise the mobilities of all ions and thus the resolving power beyond that previously feasible, while avoiding the electrical breakdown inevitable in He-rich mixtures. The increases in resolving power and ensuing peak resolution are especially significant at H2 fractions above ~50%. Higher resolution can be exchanged for acceleration of the analyses by up to ~4 times, at least. For more mobile species such as multiply-charged peptides, this exchange is presently forced by the constraints of existing FAIMS devices, but future designs optimized for H2 should consistently improve resolution for all analytes. PMID:22074292

  10. Highly efficient removal of pathogenic bacteria with magnetic graphene composite.

    PubMed

    Zhan, Sihui; Zhu, Dandan; Ma, Shuanglong; Yu, Wenchao; Jia, Yanan; Li, Yi; Yu, Hongbing; Shen, Zhiqiang

    2015-02-25

    Magnetic Fe3O4/graphene composite (abbreviated as G-Fe3O4) was synthesized successfully by solvothermal method to effectively remove both bacteriophage and bacteria in water, which was tested by HRTEM, XRD, BET, XPS, FTIR, CV, magnetic property and zeta-potential measurements. Based on the result of HRTEM, the single-sheet structure of graphene oxide and the monodisperse Fe3O4 nanoparticles on the surface of graphene can be observed obviously. The G-Fe3O4 composite were attractive for removing a wide range of pathogens including not only bacteriophage ms2, but also various bacteria such as S. aureus, E. coli, Salmonella, E. Faecium, E. faecalis, and Shigella. The removal efficiency of E. coli for G-Fe3O4 composite can achieve 93.09%, whereas it is only 54.97% with pure Fe3O4 nanoparticles. Moreover, a detailed verification test of real water samples was conducted and the removal efficiency of bacteria in real water samples with G-Fe3O4 composite can also reach 94.8%. PMID:25634911

  11. Highly Pathogenic Avian Influenza Virus Infection of Mallards with Homo- and Heterosubtypic Immunity Induced by Low Pathogenic Avian Influenza Viruses

    PubMed Central

    Fereidouni, Sasan R.; Starick, Elke; Beer, Martin; Wilking, Hendrik; Kalthoff, Donata; Grund, Christian; Häuslaigner, Rafaela; Breithaupt, Angele; Lange, Elke; Harder, Timm C.

    2009-01-01

    The potential role of wild birds as carriers of highly pathogenic avian influenza virus (HPAIV) subtype H5N1 is still a matter of debate. Consecutive or simultaneous infections with different subtypes of influenza viruses of low pathogenicity (LPAIV) are very common in wild duck populations. To better understand the epidemiology and pathogenesis of HPAIV H5N1 infections in natural ecosystems, we investigated the influence of prior infection of mallards with homo- (H5N2) and heterosubtypic (H4N6) LPAIV on exposure to HPAIV H5N1. In mallards with homosubtypic immunity induced by LPAIV infection, clinical disease was absent and shedding of HPAIV from respiratory and intestinal tracts was grossly reduced compared to the heterosubtypic and control groups (mean GEC/100 µl at 3 dpi: 3.0×102 vs. 2.3×104 vs. 8.7×104; p<0.05). Heterosubtypic immunity induced by an H4N6 infection mediated a similar but less pronounced effect. We conclude that the epidemiology of HPAIV H5N1 in mallards and probably other aquatic wild bird species is massively influenced by interfering immunity induced by prior homo- and heterosubtypic LPAIV infections. PMID:19693268

  12. High electron mobility in Ga(In)NAs films grown by molecular beam epitaxy

    SciTech Connect

    Miyashita, Naoya; Ahsan, Nazmul; Monirul Islam, Muhammad; Okada, Yoshitaka; Inagaki, Makoto; Yamaguchi, Masafumi

    2012-11-26

    We report the highest mobility values above 2000 cm{sup 2}/Vs in Si doped GaNAs film grown by molecular beam epitaxy. To understand the feature of the origin which limits the electron mobility in GaNAs, temperature dependences of mobility were measured for high mobility GaNAs and referential low mobility GaInNAs. Temperature dependent mobility for high mobility GaNAs is similar to the GaAs case, while that for low mobility GaInNAs shows large decrease in lower temperature region. The electron mobility of high quality GaNAs can be explained by intrinsic limiting factor of random alloy scattering and extrinsic factor of ionized impurity scattering.

  13. Highly pathogenic avian influenza viruses and generation of novel reassortants,United States, 2014–2015

    USGS Publications Warehouse

    Dong-Hun Lee; Justin Bahl; Mia Kim Torchetti; Mary Lea Killian; Ip, Hon S.; David E Swayne

    2016-01-01

    Asian highly pathogenic avian influenza A(H5N8) viruses spread into North America in 2014 during autumn bird migration. Complete genome sequencing and phylogenetic analysis of 32 H5 viruses identified novel H5N1, H5N2, and H5N8 viruses that emerged in late 2014 through reassortment with North American low-pathogenicity avian influenza viruses.

  14. Highly Pathogenic Avian Influenza Viruses and Generation of Novel Reassortants, United States, 2014–2015

    PubMed Central

    Lee, Dong-Hun; Bahl, Justin; Torchetti, Mia Kim; Killian, Mary Lea; Ip, Hon S.; DeLiberto, Thomas J.

    2016-01-01

    Asian highly pathogenic avian influenza A(H5N8) viruses spread into North America in 2014 during autumn bird migration. Complete genome sequencing and phylogenetic analysis of 32 H5 viruses identified novel H5N1, H5N2, and H5N8 viruses that emerged in late 2014 through reassortment with North American low-pathogenicity avian influenza viruses. PMID:27314845

  15. Highly Pathogenic Avian Influenza Viruses and Generation of Novel Reassortants, United States, 2014-2015.

    PubMed

    Lee, Dong-Hun; Bahl, Justin; Torchetti, Mia Kim; Killian, Mary Lea; Ip, Hon S; DeLiberto, Thomas J; Swayne, David E

    2016-07-01

    Asian highly pathogenic avian influenza A(H5N8) viruses spread into North America in 2014 during autumn bird migration. Complete genome sequencing and phylogenetic analysis of 32 H5 viruses identified novel H5N1, H5N2, and H5N8 viruses that emerged in late 2014 through reassortment with North American low-pathogenicity avian influenza viruses. PMID:27314845

  16. Pathogenesis of highly-pathogenic Asian PRRSV in pigs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2006, Chinese investigators reported a unique syndrome in growing swine that was highlighted by clinical signs of high fever, anorexia, listlessness, red discoloration of skin, respiratory distress and very high morbidity and mortality rates. Originally known as porcine high fever disease (PHFD),...

  17. Pathogenicity of Highly Pathogenic Avian Influenza Virus H5N1 in Naturally Infected Poultry in Egypt

    PubMed Central

    Hagag, Ibrahim Thabet; Mansour, Shimaa M. G.; Zhang, Zerui; Ali, Ahmed A. H.; Ismaiel, El-Bakry M.; Salama, Ali A.; Cardona, Carol J.; Collins, James; Xing, Zheng

    2015-01-01

    Highly pathogenic avian influenza virus (HPAIV) H5N1 has been endemic in Egypt since 2006, and there is increasing concern for its potential to become highly transmissible among humans. Infection by HPAIV H5N1 has been described in experimentally challenged birds. However, the pathogenicity of the H5N1 isolated in Egypt has never been reported in naturally infected chickens and ducks. Here we report a 2013 outbreak of HPAIV H5N1 in commercial poultry farms and backyards in Sharkia Province, Egypt. The main symptoms were ecchymosis on the shanks and feet, cyanosis of the comb and wattles, subcutaneous edema of the head and neck for chickens, and nervous signs (torticollis) for ducks. Within 48-72 hrs of the onset of illness, the average mortality rates were 22.8-30% and 28.5-40% in vaccinated chickens and non-vaccinated ducks, respectively. Tissue samples of chickens and ducks were collected for analyses with cross-section immunohistochemistry and real-time RT-PCR for specific viral RNA transcripts. While viral RNA was detected in nearly all tissues and sera collected, viral nucleoprotein was detected almost ubiquitously in all tissues, including testis. Interestingly, viral antigen was also observed in endothelial cells of most organs in chickens, and clearly detected in the trachea and brain in particular. Viral nucleoprotein was also detected in mononuclear cells of various organs, especially pulmonary tissue. We performed phylogenetic analyses and compared the genomic sequences of the hemagglutinin (HA) and nonstructural proteins (NS) among the isolated viruses, the HPAIV circulated in Egypt in the past and currently, and some available vaccine strains. Further analysis of deduced amino acids of both HA and NS1 revealed that our isolates carried molecular determinants of HPAIV, including the multibasic amino acids (PQGERRRK/KR*GLF) in the cleavage site in HA and glutamate at position 92 (D92E) in NS1. This is the first report of the pathogenicity of the HPAIVH5N

  18. High-mobility ultrathin semiconducting films prepared by spin coating

    NASA Astrophysics Data System (ADS)

    Mitzi, David B.; Kosbar, Laura L.; Murray, Conal E.; Copel, Matthew; Afzali, Ali

    2004-03-01

    The ability to deposit and tailor reliable semiconducting films (with a particular recent emphasis on ultrathin systems) is indispensable for contemporary solid-state electronics. The search for thin-film semiconductors that provide simultaneously high carrier mobility and convenient solution-based deposition is also an important research direction, with the resulting expectations of new technologies (such as flexible or wearable computers, large-area high-resolution displays and electronic paper) and lower-cost device fabrication. Here we demonstrate a technique for spin coating ultrathin (~50Å), crystalline and continuous metal chalcogenide films, based on the low-temperature decomposition of highly soluble hydrazinium precursors. We fabricate thin-film field-effect transistors (TFTs) based on semiconducting SnS2-xSex films, which exhibit n-type transport, large current densities (>105Acm-2) and mobilities greater than 10cm2V-1s-1-an order of magnitude higher than previously reported values for spin-coated semiconductors. The spin-coating technique is expected to be applicable to a range of metal chalcogenides, particularly those based on main group metals, as well as for the fabrication of a variety of thin-film-based devices (for example, solar cells, thermoelectrics and memory devices).

  19. Thermal inactivation of high pathogenicity avian influenza viruses in chicken meat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High pathogenicity avian influenza (HPAI) viruses cause severe disease with high mortality in chickens and related gallinaceous poultry. Some HPAI viruses cause systemic infections and replicate to high titers in skeletal muscle fibers. To prevent transmission of these viruses through contaminate...

  20. High- and Low-Mobility Stages in the Synaptic Vesicle Cycle

    PubMed Central

    Kamin, Dirk; Lauterbach, Marcel A.; Westphal, Volker; Keller, Jan; Schönle, Andreas; Hell, Stefan W.; Rizzoli, Silvio O.

    2010-01-01

    Abstract Synaptic vesicles need to be mobile to reach their release sites during synaptic activity. We investigated vesicle mobility throughout the synaptic vesicle cycle using both conventional and subdiffraction-resolution stimulated emission depletion fluorescence microscopy. Vesicle tracking revealed that recently endocytosed synaptic vesicles are highly mobile for a substantial time period after endocytosis. They later undergo a maturation process and integrate into vesicle clusters where they exhibit little mobility. Despite the differences in mobility, both recently endocytosed and mature vesicles are exchanged between synapses. Electrical stimulation does not seem to affect the mobility of the two types of vesicles. After exocytosis, the vesicle material is mobile in the plasma membrane, although the movement appears to be somewhat limited. Increasing the proportion of fused vesicles (by stimulating exocytosis while simultaneously blocking endocytosis) leads to substantially higher mobility. We conclude that both high- and low-mobility states are characteristic of synaptic vesicle movement. PMID:20643088

  1. The "City Migrant" Dilemma: Building Community at High-Mobility Urban Schools.

    ERIC Educational Resources Information Center

    Nakagawa, Kathryn; Stafford, Mary E.; Fisher, Teresa A.; Matthews, Linda

    2002-01-01

    Surveyed urban elementary school principals and conducted case studies at high-mobility schools, examining how schools with higher mobility levels attempted to build community. Schools with high mobility levels implemented many programs and practices to help families, such as access to counseling services and adult education classes as well as…

  2. Highly Charged Clusters of Fullerenes: Charge Mobility and Appearance Sizes

    NASA Astrophysics Data System (ADS)

    Manil, B.; Maunoury, L.; Huber, B. A.; Jensen, J.; Schmidt, H. T.; Zettergren, H.; Cederquist, H.; Tomita, S.; Hvelplund, P.

    2003-11-01

    Clusters of fullerenes (C60,C70)n are produced in a gas aggregation source and are multiply ionized in collisions with highly charged Xe20+,30+ ions. Their stabilities and decay processes are analyzed with high-resolution time-of-flight mass spectrometry. Fullerene clusters in charge states up to q=5 have been observed and appearance sizes are found to be as small as napp=5, 10, 21, and 33 for q=2, 3, 4, and 5, respectively. The analysis of the multicoincident fragmentation spectra indicates a high charge mobility. This is in contrast to charge localization effects which have been reported for Arq+n rare gas clusters. Clusters of fullerenes are found to be conducting when multiply charged.

  3. Highly charged clusters of fullerenes: charge mobility and appearance sizes.

    PubMed

    Manil, B; Maunoury, L; Huber, B A; Jensen, J; Schmidt, H T; Zettergren, H; Cederquist, H; Tomita, S; Hvelplund, P

    2003-11-21

    Clusters of fullerenes (C60,C70)(n) are produced in a gas aggregation source and are multiply ionized in collisions with highly charged Xe(20+,30+) ions. Their stabilities and decay processes are analyzed with high-resolution time-of-flight mass spectrometry. Fullerene clusters in charge states up to q=5 have been observed and appearance sizes are found to be as small as n(app)=5, 10, 21, and 33 for q=2, 3, 4, and 5, respectively. The analysis of the multicoincident fragmentation spectra indicates a high charge mobility. This is in contrast to charge localization effects which have been reported for Ar(q+)(n) rare gas clusters. Clusters of fullerenes are found to be conducting when multiply charged. PMID:14683315

  4. High Temperature and Bacteriophages Can Indirectly Select for Bacterial Pathogenicity in Environmental Reservoirs

    PubMed Central

    Friman, Ville-Petri; Hiltunen, Teppo; Jalasvuori, Matti; Lindstedt, Carita; Laanto, Elina; Örmälä, Anni-Maria; Laakso, Jouni; Mappes, Johanna; Bamford, Jaana K. H.

    2011-01-01

    The coincidental evolution hypothesis predicts that traits connected to bacterial pathogenicity could be indirectly selected outside the host as a correlated response to abiotic environmental conditions or different biotic species interactions. To investigate this, an opportunistic bacterial pathogen, Serratia marcescens, was cultured in the absence and presence of the lytic bacteriophage PPV (Podoviridae) at 25°C and 37°C for four weeks (N = 5). At the end, we measured changes in bacterial phage-resistance and potential virulence traits, and determined the pathogenicity of all bacterial selection lines in the Parasemia plantaginis insect model in vivo. Selection at 37°C increased bacterial motility and pathogenicity but only in the absence of phages. Exposure to phages increased the phage-resistance of bacteria, and this was costly in terms of decreased maximum population size in the absence of phages. However, this small-magnitude growth cost was not greater with bacteria that had evolved in high temperature regime, and no trade-off was found between phage-resistance and growth rate. As a result, phages constrained the evolution of a temperature-mediated increase in bacterial pathogenicity presumably by preferably infecting the highly motile and virulent bacteria. In more general perspective, our results suggest that the traits connected to bacterial pathogenicity could be indirectly selected as a correlated response by abiotic and biotic factors in environmental reservoirs. PMID:21423610

  5. Phosphorene: A New High-Mobility 2D Semiconductor

    NASA Astrophysics Data System (ADS)

    Liu, Han; Neal, Adam; Zhu, Zhen; Tomanek, David; Ye, Peide

    2014-03-01

    The rise of 2D crystals has opened various possibilities for future electrical and optical applications. MoS2 n-type transistors are showing great potential in ultra-scaled and low-power electronics. Here, we introduce phosphorene, a name we coined for 2D few-layer black phosphorus, a new 2D material with layered structure. We perform ab initio band structure calculations and show that the fundamental band gap depends sensitively on the number of layers. We observe transport behavior, which shows a mobility variation in the 2D plane. High on-current of 194 mA/mm, high hole mobility up to 286 cm2/V .s and on/off ratio up to 104 was achieved with phosphorene transistors at room temperature. Schottky barrier height at the metal/phosphorene interface was also measured as a function of temperature. We demonstrate a CMOS inverter with combination to MoS2 NMOS transistors, which shows great potential for semiconducting 2D crystals in future electronic, optoelectronic and flexible electronic devices.

  6. Detection and prevention of highly pathogenic avian influenza in communities with high poultry disease burdens.

    PubMed

    Cardona, Carol J; Byarugaba, Denis; Mbuthia, Paul; Aning, George; Sourou, Sabi; Bunn, David A; Msoffe, Peter L

    2010-03-01

    The implementation of strategies to detect, prevent, and control highly pathogenic avian influenza (HPAI) in developing countries presents several challenges, one of which is the presence of other diseases in poultry populations. Training workshops in developing countries using the Avian Flu School have revealed that in areas with heavy Newcastle disease burdens, smallholder poultry keepers do not recognize HPAI as an immediate threat. We have developed a strategy to address the more proximal needs and priorities of communities with free-ranging poultry flocks as a means to create value in poultry, and thus to improve disease detection and prevention overall. To this end, we have created the Poultry Health and Well-Being for Development project, which trains graduate veterinarians and paraprofessionals in poultry disease diagnosis, control, and treatment. These trainees then serve their local communities to improve poultry health and to implement disease detection and management programs. PMID:20521727

  7. A high-flux BEC source for mobile atom interferometers

    NASA Astrophysics Data System (ADS)

    Rudolph, Jan; Herr, Waldemar; Grzeschik, Christoph; Sternke, Tammo; Grote, Alexander; Popp, Manuel; Becker, Dennis; Müntinga, Hauke; Ahlers, Holger; Peters, Achim; Lämmerzahl, Claus; Sengstock, Klaus; Gaaloul, Naceur; Ertmer, Wolfgang; Rasel, Ernst M.

    2015-06-01

    Quantum sensors based on coherent matter-waves are precise measurement devices whose ultimate accuracy is achieved with Bose-Einstein condensates (BECs) in extended free fall. This is ideally realized in microgravity environments such as drop towers, ballistic rockets and space platforms. However, the transition from lab-based BEC machines to robust and mobile sources with comparable performance is a challenging endeavor. Here we report on the realization of a miniaturized setup, generating a flux of 4× {{10}5} quantum degenerate 87Rb atoms every 1.6 s. Ensembles of 1× {{10}5} atoms can be produced at a 1 Hz rate. This is achieved by loading a cold atomic beam directly into a multi-layer atom chip that is designed for efficient transfer from laser-cooled to magnetically trapped clouds. The attained flux of degenerate atoms is on par with current lab-based BEC experiments while offering significantly higher repetition rates. Additionally, the flux is approaching those of current interferometers employing Raman-type velocity selection of laser-cooled atoms. The compact and robust design allows for mobile operation in a variety of demanding environments and paves the way for transportable high-precision quantum sensors.

  8. Towards reliable multi-pathogen biosensors using high-dimensional encoding and decoding techniques

    NASA Astrophysics Data System (ADS)

    Chakrabartty, Shantanu; Liu, Yang

    2008-08-01

    Advances in micro-nano-biosensor fabrication are enabling technology that can integrate a large number of biological recognition elements within a single package. As a result, hundreds to millions of tests can be performed simultaneously and can facilitate rapid detection of multiple pathogens in a given sample. However, it is an open question as to how to exploit the high-dimensional nature of the multi-pathogen testing for improving the detection reliability a typical biosensor system. In this paper, we discuss two complementary high-dimensional encoding/decoding methods for improving the reliability of multi-pathogen detection. The first method uses a support vector machine (SVM) to learn the non-linear detection boundaries in the high-dimensional measurement space. The second method uses a forward error correcting (FEC) technique to synthetically introduce redundant patterns on the biosensor which can then be efficiently decoded. In this paper, experimental and simulation studies are based on a model conductimetric lateral flow immunoassay that uses antigen-antibody interaction in conjunction with a polyaniline transducer to detect presence or absence of pathogen in a given sample. Our results show that both SVM and FEC techniques can improve the detection performance by exploiting cross-reaction amongst multiple recognition sites on the biosensor. This is contrary to many existing methods used in pathogen detection technology where the main emphasis has been reducing the effects of cross-reaction and coupling instead of exploiting them as side information.

  9. A Preliminary Analysis of Differential Characteristics Between High and Low Mobile Medical School Faculty.

    ERIC Educational Resources Information Center

    Anderson, Philip W.; Larson, Thomas A.

    Excessive faculty mobility, from the medical school standpoint, can be interpreted as an undesirable event to the institution. Are there identifiable personal and institutional characteristics that are associated with high employment mobility? A mobility index that shows the relationship between the number of medical school jobs held and the…

  10. Highly Mobile Children and Youth with Disabilities: Policies and Practices in Five States. inForum

    ERIC Educational Resources Information Center

    Pierce, Luzanne; Ahearn, Eileen

    2007-01-01

    This document's primary focus is on a subset of the population of mobile children--infants, preschoolers, children and youth with disabilities and their families who are highly mobile. First, a background section provides information about policies and practices developed for mobile children at the federal level under the McKinney-Vento Program.…

  11. False positives complicate ancient pathogen identifications using high-throughput shotgun sequencing

    PubMed Central

    2014-01-01

    Background Identification of historic pathogens is challenging since false positives and negatives are a serious risk. Environmental non-pathogenic contaminants are ubiquitous. Furthermore, public genetic databases contain limited information regarding these species. High-throughput sequencing may help reliably detect and identify historic pathogens. Results We shotgun-sequenced 8 16th-century Mixtec individuals from the site of Teposcolula Yucundaa (Oaxaca, Mexico) who are reported to have died from the huey cocoliztli (‘Great Pestilence’ in Nahautl), an unknown disease that decimated native Mexican populations during the Spanish colonial period, in order to identify the pathogen. Comparison of these sequences with those deriving from the surrounding soil and from 4 precontact individuals from the site found a wide variety of contaminant organisms that confounded analyses. Without the comparative sequence data from the precontact individuals and soil, false positives for Yersinia pestis and rickettsiosis could have been reported. Conclusions False positives and negatives remain problematic in ancient DNA analyses despite the application of high-throughput sequencing. Our results suggest that several studies claiming the discovery of ancient pathogens may need further verification. Additionally, true single molecule sequencing’s short read lengths, inability to sequence through DNA lesions, and limited ancient-DNA-specific technical development hinder its application to palaeopathology. PMID:24568097

  12. Compact and mobile high resolution PET brain imager

    DOEpatents

    Majewski, Stanislaw; Proffitt, James

    2011-02-08

    A brain imager includes a compact ring-like static PET imager mounted in a helmet-like structure. When attached to a patient's head, the helmet-like brain imager maintains the relative head-to-imager geometry fixed through the whole imaging procedure. The brain imaging helmet contains radiation sensors and minimal front-end electronics. A flexible mechanical suspension/harness system supports the weight of the helmet thereby allowing for patient to have limited movements of the head during imaging scans. The compact ring-like PET imager enables very high resolution imaging of neurological brain functions, cancer, and effects of trauma using a rather simple mobile scanner with limited space needs for use and storage.

  13. High-ratio grid considerations in mobile chest radiography

    SciTech Connect

    Scott, Alexander W.; Gauntt, David M.; Yester, Michael V.; Barnes, Gary T.

    2012-06-15

    Purpose: Grids are often not used in mobile chest radiography, and when used, they have a low ratio and are often inaccurately aligned. Recently, a mobile radiography automatic grid alignment system (MRAGA) was developed that accurately and automatically aligns the focal spot with the grid. The objective of this study is to investigate high-ratio grid tradeoffs in mobile chest radiography at fixed patient dose when the focal spot lies on the focal axis of the grid. Methods: The chest phantoms (medium and large) used in this study were modifications of the ANSI (American National Standards Institute) chest phantom and consisted of layers of Lucite Trade-Mark-Sign , aluminum, and air. For the large chest phantom, the amount of Lucite and aluminum was increased by 50% over the medium phantom. Further modifications included a mediastinum insert and the addition of contrast targets in the lung and mediastinum regions. Five high-ratio grids were evaluated and compared to the nongrid results at x-ray tube potentials of 80, 90, 100, and 110 kVp for both phantoms. The grids investigated were from two manufacturers: 12:1 and 15:1 aluminum interspace grids from one and 10:1, 13:1, and 15:1 fiber interspace grids from another. MRAGA was employed to align the focal spot with the grid. All exposures for a given kVp and phantom size were made using the same current-time product (CTP). The phantom images were acquired using computed radiography, and contrast-to-noise ratios (CNR) and CNR improvement factors (k{sub CNR}) were determined from the resultant images. The noise in the targets and the contrast between the targets and their backgrounds were calculated using a local detrending correction, and the CNR was calculated as the ratio of the target contrast to the background noise. k{sub CNR} was defined as the ratio of the CNR imaged with the grid divided by the CNR imaged without a grid. Results: The CNR values obtained with a high-ratio grid were 4%-65% higher than those

  14. Mobile sensor for high resolution NMR spectroscopy and imaging

    NASA Astrophysics Data System (ADS)

    Danieli, Ernesto; Mauler, Jörg; Perlo, Juan; Blümich, Bernhard; Casanova, Federico

    2009-05-01

    In this work we describe the construction of a mobile NMR tomograph with a highly homogeneous magnetic field. Fast MRI techniques as well as NMR spectroscopy measurements were carried out. The magnet is based on a Halbach array built from identical permanent magnet blocks generating a magnetic field of 0.22 T. To shim the field inhomogeneities inherent to magnet arrays constructed from these materials, a shim strategy based on the use of movable magnet blocks is employed. With this approach a reduction of the line-width from ˜20 kHz to less than 0.1 kHz was achieved, that is by more than two orders of magnitude, in a volume of 21 cm 3. Implementing a RARE sequence, 3D images of different objects placed in this volume were obtained in short experimental times. Moreover, by reducing the sample size to 1 cm 3, sub ppm resolution is obtained in 1H NMR spectra.

  15. High-mobility Group Box 1 [HMGB1] and Cancer

    PubMed Central

    Tang, Daolin; Kang, Rui; Zeh, Herbert J.; Lotze, Michael T.

    2009-01-01

    High-mobility group box 1 protein (HMGB1), a chromatin associated nuclear protein and extracellular damage associated molecular pattern molecule (DAMP), is an evolutionarily ancient and critical regulator of cell death and survival. Overexpression of HMGB1 is associated with each of the hallmarks of cancer including unlimited replicative potential, ability to develop blood vessels (angiogenesis), evasion of programmed cell death (apoptosis), self-sufficiency in growth signals, insensitivity to inhibitors of growth, inflammation, tissue invasion and metastasis. Our studies and those of our colleagues suggest that HMGB1 is central to cancer (abnormal wound healing) and many of the findings in normal wound healing as well. Here, we focus on the role of HMGB1 in cancer, the mechanisms by which it contributes to carcinogenesis, and therapeutic strategies based on targeting HMGB1. PMID:20123075

  16. A third generation mobile high energy radiography system

    SciTech Connect

    Fry, D.A.; Valdez, J.E.; Johnson, C.S.; Kimerly, H.J.; Vananne, J.R.

    1997-12-01

    A third generation mobile high energy radiographic capability has been completed and put into service by the Los Alamos National Laboratory. The system includes a 6 MeV linac x-ray generator, Co-60 gamma source, all-terrain transportation, on-board power, real-time radiography (RTR), a control center, and a complete darkroom capability. The latest version includes upgraded and enhanced portability, flexibility, all-terrain operation, all-weather operation, and ease of use features learned from experience with the first and second generation systems. All systems were required to have the following characteristics; all-terrain, all-weather operation, self-powered, USAF airlift compatible, reliable, simple to setup, easy to operate, and all components two-person portable. The systems have met these characteristics to differing degrees, as is discussed in the following section, with the latest system being the most capable.

  17. Photoluminescent lateral-flow immunoassay revealed by graphene oxide: highly sensitive paper-based pathogen detection.

    PubMed

    Morales-Narváez, Eden; Naghdi, Tina; Zor, Erhan; Merkoçi, Arben

    2015-08-18

    A paper-based lateral flow immunoassay for pathogen detection that avoids the use of secondary antibodies and is revealed by the photoluminescence quenching ability of graphene oxide is reported. Escherichia coli has been selected as a model pathogen. The proposed device is able to display a highly specific and sensitive performance with a limit of detection of 10 CFU mL(-1) in standard buffer and 100 CFU mL(-1) in bottled water and milk. This low-cost disposable and easy-to-use device will prove valuable for portable and automated diagnostics applications. PMID:26205473

  18. The role of vaccines and vaccination in high pathogenicity avian influenza control and eradication

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty epizootics of high pathogenicity avian influenza (HPAI) have occurred in the world since influenza was identified as the etiology in 1955. Twenty-four of the epizootics were eradicated by using stamping-out programs composed of education, biosecurity, rapid diagnostics and surveillance, and ...

  19. Novel Eurasian highly pathogenic influenza A H5 viruses in wild birds, Washington, USA

    USGS Publications Warehouse

    Ip, Hon S.; Torchetti, Mia Kim; Crespo, Rocio; Kohrs, Paul; DeBruyn, Paul; Mansfield, Kristin G.; Baszler, Timothy; Badcoe, Lyndon; Bodenstein, Barbara L.; Shearn-Bochsler, Valerie I.; Killian, Mary Lea; Pederson, Janice C.; Hines, Nichole; Gidlewski, Thomas; DeLiberto, Thomas; Sleeman, Jonathan M.

    2015-01-01

    Novel Eurasian lineage avian influenza A(H5N8) virus has spread rapidly and globally since January 2014. In December 2014, H5N8 and reassortant H5N2 viruses were detected in wild birds in Washington, USA, and subsequently in backyard birds. When they infect commercial poultry, these highly pathogenic viruses pose substantial trade issues.

  20. Airborne transmission of H5N1 high pathogenicity avian influenza viruses during simulated home slaughter

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Most H5N1 human infections have occurred following exposure to H5N1 high pathogenicity avian influenza (HPAI) virus-infected poultry, especially when poultry are home slaughtered or slaughtered in live poultry markets. Previous studies have demonstrated that slaughter of clade 1 isolate A/Vietnam/1...

  1. Global expansion of high pathogenicity avian influenza: implications on prevention and control programs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The H5N1 high pathogenicity avian influenza (HPAI) virus emerged in China during 1996 and has spread to infect poultry and/or wild birds in 63 countries during the past 18 years. The majority of the recent outbreaks of H5N1 HPAI have occurred in Indonesia, Egypt, Vietnam, and Bangladesh, in decreas...

  2. Global expansion of high pathogenicity avian influenza: implications on prevention and control programs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The H5N1 high pathogenicity avian influenza (HPAI) virus emerged in China during 1996 and has spread to infect poultry and/or wild birds in 63 countries during the past 18 years. The majority of the recent outbreaks of H5N1 HPAI have occurred in Indonesia, Egypt, Vietnam, and Bangladesh, in decreasi...

  3. Two Asian highly pathogenic strains of Type 2 PRRSV in United States swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Highly pathogenic PRRSV (HP-PRRSV) has been circulating in Asia for 7 years. rJXwn06 and rSRV07 were rescued from infectious clones of two HP-PRRSV for investigation at the National Animal Disease Center. The clinical disease and viral replication kinetics of HP-PRRSV were compared to prototype stra...

  4. Imaging mass spectrometry and genome mining reveal highly antifungal virulence factor of mushroom soft rot pathogen.

    PubMed

    Graupner, Katharina; Scherlach, Kirstin; Bretschneider, Tom; Lackner, Gerald; Roth, Martin; Gross, Harald; Hertweck, Christian

    2012-12-21

    Caught in the act: imaging mass spectrometry of a button mushroom infected with the soft rot pathogen Janthinobacterium agaricidamnosum in conjunction with genome mining revealed jagaricin as a highly antifungal virulence factor that is not produced under standard cultivation conditions. The structure of jagaricin was rigorously elucidated by a combination of physicochemical analyses, chemical derivatization, and bioinformatics. PMID:23161559

  5. Chlorine inactivation of H5N1 highly pathogenic avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two Asian strains of H5N1 highly pathogenic avian influenza virus were studied to determine their resistance to chlorination. Experiments were conducted at two pH levels (pH 7 and 8) at 5 C. CT (chlorine concentration x exposure time) values were calculated for different levels of inactivation. R...

  6. Domestic pigs have low susceptibility to H5N1 highly pathogenic avian influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background. Genetic reassortment of H5N1 highly pathogenic avian influenza viruses (HPAI) with currently circulating human influenza A strains is one possibility that could lead to efficient human-to-human transmissibility. Domestic pigs which are susceptible to infection with both human and avian ...

  7. Evolution of highly pathogenic avian influenza H5N1 viruses in Egypt indicating progressive adaptation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Highly pathogenic avian influenza (HPAI) virus of the H5N1 subtype was first diagnosed in poultry in Egypt in 2006, and since then the disease became enzootic in poultry throughout the country affecting the poultry industry and village poultry as well as infecting humans. Vaccination has been used ...

  8. Global assessments of high pathogenicity avian influenza control, including vaccination programs

    Technology Transfer Automated Retrieval System (TEKTRAN)

    There have been 32 epizootics of H5 or H7 high pathogenicity avian influenza (HPAI) from 1959 to early 2013. The largest has been the H5N1 HPAI which began in Guangdong China in 1996, and has affected over 250 million poultry and/or wild birds in 63 countries. For most countries, stamping-out progra...

  9. Inhibition of enteric pathogens using integrated high intensity 405 nm LED on the surface of almonds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The disinfecting properties of 405 nm light were investigated against Escherichia coli O157:H7, Salmonella, and their non-pathogenic surrogates inoculated onto the surface of almonds. High intensity monochromatic light was generated from an array of narrow-band 405 nm light emitting diodes (LED). Al...

  10. Effects of high hydrostatis pressure on Eimeria Acervulina pathogenicity, immunogenicity and structural integrity.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eimeria acervulina is a protozoan parasite that can cause intestinal lesions and reduced weight gain in chickens. E. acervulina oocysts were treated by high hydrostatic pressure and evaluated for pathogenicity, immunogenicity, and structural integrity. Pressure treatment of E. acervulina oocysts a...

  11. Highly pathogenic avian influenza virus and generation of novel reassortants, United States, 2014-2015

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Asian highly pathogenic avian influenza A(H5N8) viruses spread into North America in 2014 during autumn bird migration. Complete genome sequencing and phylogenetic analysis of 32 H5 viruses identified novel H5N1, H5N2, and H5N8 viruses that emerged in late 2014 through reassortment with North Americ...

  12. Immediate early responses of avian tracheal epithelial cells to infection with highly pathogenic avian influenza

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Highly pathogenic (HP) avian influenza viruses (AIV) present an on going threat to the U.S. poultry industry. In order to develop new AIV control strategies it is necessary to understand the underlying mechanism of viral infection. Because the early events of AIV infection can occur on tracheal ep...

  13. Current status and future needs in diagnostics and vaccines for high pathogenicity avian influenza

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since 1959, 31 epizootics of high pathogenicity avian influenza (HPAI) have occurred in birds. Rapid detection and accurate identification of HPAI has been critical to controlling such epizootics in poultry. Specific paradigms for the detection and diagnosis of avian influenza virus (AIV) in poultry...

  14. Susceptibility of wood ducks (Aix sponsa) to H5N1 highly pathogenic avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since 2002, H5N1 highly pathogenic avian influenza (HPAI) viruses have caused mortality in numerous species of wild birds. Although these infections document the susceptibility of wild birds to H5N1 HPAI viruses and the spillover of these viruses from infected domestic birds to wild birds, it is un...

  15. Immediate early responses of avian tracheal epithelial cells to infection with highly pathogenic avian invluenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Highly pathogenic (HP) avian influenza viruses (AIV) present an ongoing threat to the world poultry industry. In order to develop new AIV control strategies it is necessary to understand the underlying mechanism of viral infection at mucosal respiratory sites. Chicken and duck tracheal epithelial ...

  16. Susceptibility of wood ducks to H5N1 highly pathogenic avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since 2002, H5N1 highly pathogenic avian influenza (HPAI) viruses have caused mortality in numerous species of wild birds; this is atypical for avian influenza virus (AIV) infections in wild birds, especially for species in the Order Anseriformes. Although these infections document the susceptibili...

  17. Update on H7N3 highly pathogenic avian influenza in Mexico

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In June of 2012, an H7N3 highly pathogenic avian influenza (HPAI) virus was identified as the cause of a severe disease outbreak in commercial laying chicken farms in Jalisco, Mexico. This region is responsible for approximately 55% of the eggs produced in Mexico, and infection with this virus seve...

  18. Human Infection with Highly Pathogenic A(H7N7) Avian Influenza Virus, Italy, 2013

    PubMed Central

    Rossini, Giada; Facchini, Marzia; Vaccari, Gabriele; Di Trani, Livia; Di Martino, Angela; Gaibani, Paolo; Vocale, Caterina; Cattoli, Giovanni; Bennett, Michael; McCauley, John W.; Rezza, Giovanni; Moro, Maria Luisa; Rangoni, Roberto; Finarelli, Alba Carola; Landini, Maria Paola; Castrucci, Maria Rita; Donatelli, Isabella

    2014-01-01

    During an influenza A(H7N7) virus outbreak among poultry in Italy during August–September 2013, infection with a highly pathogenic A(H7N7) avian influenza virus was diagnosed for 3 poultry workers with conjunctivitis. Genetic analyses revealed that the viruses from the humans were closely related to those from chickens on affected farms. PMID:25271444

  19. Impact of poultry vaccines on control of H5N1 high pathogenicity avian influenza

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Use of vaccines against avian influenza (AI) have been sporadic in poultry until 2002 when the H5N1 high pathogenicity avian influenza (HPAI) spread from China to Hong Kong, and then multiple southeast Asian countries in 2003-2004, and to Europe in 2005, and Africa in 2006. Over the past 40 years, ...

  20. High pathogenicity avian influenza virus in the reproductive tract of chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Infection with high pathogenicity avian influenza virus (HPAIV) has been associated with a wide range of clinical manifestations in poultry including severe depression in egg production and isolation of HPAIV from eggs laid by infected hens. To evaluate the pathobiology in the reproductive tract of...

  1. Novel Eurasian Highly Pathogenic Avian Influenza A H5 Viruses in Wild Birds, Washington, USA, 2014

    PubMed Central

    Ip, Hon S.; Crespo, Rocio; Kohrs, Paul; DeBruyn, Paul; Mansfield, Kristin G.; Baszler, Timothy; Badcoe, Lyndon; Bodenstein, Barbara; Shearn-Bochsler, Valerie; Killian, Mary Lea; Pedersen, Janice C.; Hines, Nichole; Gidlewski, Thomas; DeLiberto, Thomas; Sleeman, Jonathan M.

    2015-01-01

    Novel Eurasian lineage avian influenza A(H5N8) virus has spread rapidly and globally since January 2014. In December 2014, H5N8 and reassortant H5N2 viruses were detected in wild birds in Washington, USA, and subsequently in backyard birds. When they infect commercial poultry, these highly pathogenic viruses pose substantial trade issues. PMID:25898265

  2. Highly pathogenic Chinese porcine reproductive and respiratory syndrome virus strain JXwn06 in US swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2006, a large-scale outbreak of highly pathogenic atypical porcine reproductive and respiratory syndrome virus (PRRSV) spread throughout the swine population in China. Causative PRRSV isolates were characterized genetically by a unique 30aa deletion in PRRSV nonstructural protein 2 and clinically...

  3. High-κ oxide nanoribbons as gate dielectrics for high mobility top-gated graphene transistors

    PubMed Central

    Liao, Lei; Bai, Jingwei; Qu, Yongquan; Lin, Yung-chen; Li, Yujing; Huang, Yu; Duan, Xiangfeng

    2010-01-01

    Deposition of high-κ dielectrics onto graphene is of significant challenge due to the difficulties of nucleating high quality oxide on pristine graphene without introducing defects into the monolayer of carbon lattice. Previous efforts to deposit high-κ dielectrics on graphene often resulted in significant degradation in carrier mobility. Here we report an entirely new strategy to integrate high quality high-κ dielectrics with graphene by first synthesizing freestanding high-κ oxide nanoribbons at high temperature and then transferring them onto graphene at room temperature. We show that single crystalline Al2O3 nanoribbons can be synthesized with excellent dielectric properties. Using such nanoribbons as the gate dielectrics, we have demonstrated top-gated graphene transistors with the highest carrier mobility (up to 23,600 cm2/V·s) reported to date, and a more than 10-fold increase in transconductance compared to the back-gated devices. This method opens a new avenue to integrate high-κ dielectrics on graphene with the preservation of the pristine nature of graphene and high carrier mobility, representing an important step forward to high-performance graphene electronics. PMID:20308584

  4. Glycan-based high-affinity ligands for toxins and pathogen receptors.

    PubMed

    Kulkarni, Ashish A; Weiss, Alison A; Iyer, Suri S

    2010-03-01

    Glycans decorate over 95% of the mammalian cell surface in the form of glycolipids and glycoproteins. Several toxins and pathogens bind to these glycans to enter the cells. Understanding the fundamentals of the complex interplay between microbial pathogens and their glycan receptors at the molecular level could lead to the development of novel therapeutics and diagnostics. Using Shiga toxin and influenza virus as examples, we describe the complex biological interface between host glycans and these infectious agents, and recent strategies to develop glycan-based high-affinity ligands. These molecules are expected to ultimately be incorporated into diagnostics and therapeutics, and can be used as probes to study important biological processes. Additionally, by focusing on the specific glycans that microbial pathogens target, we can begin to decipher the "glycocode" and how these glycans participate in normal and aberrant cellular communication. PMID:20135686

  5. High-Throughput Biosensors for Multiplexed Food-Borne Pathogen Detection

    NASA Astrophysics Data System (ADS)

    Gehring, Andrew G.; Tu, Shu-I.

    2011-07-01

    Incidental contamination of foods by pathogenic bacteria and/or their toxins is a serious threat to public health and the global economy. The presence of food-borne pathogens and toxins must be rapidly determined at various stages of food production, processing, and distribution. Producers, processors, regulators, retailers, and public health professionals need simple and cost-effective methods to detect different species or serotypes of bacteria and associated toxins in large numbers of food samples. This review addresses the desire to replace traditional microbiological plate culture with more timely and less cumbersome rapid, biosensor-based methods. Emphasis focuses on high-throughput, multiplexed techniques that allow for simultaneous testing of numerous samples, in rapid succession, for multiple food-borne analytes (primarily pathogenic bacteria and/or toxins).

  6. HIGH SENSITIVE PCR METHOD FOR DETECTION OF PATHOGENIC Leptospira spp. IN PARAFFIN-EMBEDDED TISSUES

    PubMed Central

    Noda, Angel Alberto; Rodríguez, Islay; Rodríguez, Yaindrys; Govín, Anamays; Fernández, Carmen; Obregón, Ana Margarita

    2014-01-01

    This study describes the development and application of a new PCR assay for the specific detection of pathogenic leptospires and its comparison with a previously reported PCR protocol. New primers were designed for PCR optimization and evaluation in artificially-infected paraffin-embedded tissues. PCR was then applied to post-mortem, paraffin-embedded samples, followed by amplicon sequencing. The PCR was more efficient than the reported protocol, allowing the amplification of expected DNA fragment from the artificially infected samples and from 44% of the post-mortem samples. The sequences of PCR amplicons from different patients showed >99% homology with pathogenic leptospires DNA sequences. The applicability of a highly sensitive and specific tool to screen histological specimens for the detection of pathogenic Leptospira spp. would facilitate a better assessment of the prevalence and epidemiology of leptospirosis, which constitutes a health problem in many countries. PMID:25229221

  7. High mobility and high stability glassy metal-oxynitride materials and devices

    PubMed Central

    Lee, Eunha; Kim, Taeho; Benayad, Anass; Hur, Jihyun; Park, Gyeong-Su; Jeon, Sanghun

    2016-01-01

    In thin film technology, future semiconductor and display products with high performance, high density, large area, and ultra high definition with three-dimensional functionalities require high performance thin film transistors (TFTs) with high stability. Zinc oxynitride, a composite of zinc oxide and zinc nitride, has been conceded as a strong substitute to conventional semiconductor film such as silicon and indium gallium zinc oxide due to high mobility value. However, zinc oxynitride has been suffered from poor reproducibility due to relatively low binding energy of nitrogen with zinc, resulting in the instability of composition and its device performance. Here we performed post argon plasma process on zinc oxynitride film, forming nano-crystalline structure in stable amorphous matrix which hampers the reaction of oxygen with zinc. Therefore, material properties and device performance of zinc oxynitride are greatly enhanced, exhibiting robust compositional stability even exposure to air, uniform phase, high electron mobility, negligible fast transient charging and low noise characteristics. Furthermore, We expect high mobility and high stability zinc oxynitride customized by plasma process to be applicable to a broad range of semiconductor and display devices. PMID:27044371

  8. High mobility and high stability glassy metal-oxynitride materials and devices.

    PubMed

    Lee, Eunha; Kim, Taeho; Benayad, Anass; Hur, Jihyun; Park, Gyeong-Su; Jeon, Sanghun

    2016-01-01

    In thin film technology, future semiconductor and display products with high performance, high density, large area, and ultra high definition with three-dimensional functionalities require high performance thin film transistors (TFTs) with high stability. Zinc oxynitride, a composite of zinc oxide and zinc nitride, has been conceded as a strong substitute to conventional semiconductor film such as silicon and indium gallium zinc oxide due to high mobility value. However, zinc oxynitride has been suffered from poor reproducibility due to relatively low binding energy of nitrogen with zinc, resulting in the instability of composition and its device performance. Here we performed post argon plasma process on zinc oxynitride film, forming nano-crystalline structure in stable amorphous matrix which hampers the reaction of oxygen with zinc. Therefore, material properties and device performance of zinc oxynitride are greatly enhanced, exhibiting robust compositional stability even exposure to air, uniform phase, high electron mobility, negligible fast transient charging and low noise characteristics. Furthermore, We expect high mobility and high stability zinc oxynitride customized by plasma process to be applicable to a broad range of semiconductor and display devices. PMID:27044371

  9. High mobility and high stability glassy metal-oxynitride materials and devices

    NASA Astrophysics Data System (ADS)

    Lee, Eunha; Kim, Taeho; Benayad, Anass; Hur, Jihyun; Park, Gyeong-Su; Jeon, Sanghun

    2016-04-01

    In thin film technology, future semiconductor and display products with high performance, high density, large area, and ultra high definition with three-dimensional functionalities require high performance thin film transistors (TFTs) with high stability. Zinc oxynitride, a composite of zinc oxide and zinc nitride, has been conceded as a strong substitute to conventional semiconductor film such as silicon and indium gallium zinc oxide due to high mobility value. However, zinc oxynitride has been suffered from poor reproducibility due to relatively low binding energy of nitrogen with zinc, resulting in the instability of composition and its device performance. Here we performed post argon plasma process on zinc oxynitride film, forming nano-crystalline structure in stable amorphous matrix which hampers the reaction of oxygen with zinc. Therefore, material properties and device performance of zinc oxynitride are greatly enhanced, exhibiting robust compositional stability even exposure to air, uniform phase, high electron mobility, negligible fast transient charging and low noise characteristics. Furthermore, We expect high mobility and high stability zinc oxynitride customized by plasma process to be applicable to a broad range of semiconductor and display devices.

  10. In Vitro Emergence of High Persistence upon Periodic Aminoglycoside Challenge in the ESKAPE Pathogens.

    PubMed

    Michiels, Joran Elie; Van den Bergh, Bram; Verstraeten, Natalie; Fauvart, Maarten; Michiels, Jan

    2016-08-01

    Health care-associated infections present a major threat to modern medical care. Six worrisome nosocomial pathogens-Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter spp.-are collectively referred to as the "ESKAPE bugs." They are notorious for extensive multidrug resistance, yet persistence, or the phenotypic tolerance displayed by a variant subpopulation, remains underappreciated in these pathogens. Importantly, persistence can prevent eradication of antibiotic-sensitive bacterial populations and is thought to act as a catalyst for the development of genetic resistance. Concentration- and time-dependent aminoglycoside killing experiments were used to investigate persistence in the ESKAPE pathogens. Additionally, a recently developed method for the experimental evolution of persistence was employed to investigate adaptation to high-dose, extended-interval aminoglycoside therapy in vitro We show that ESKAPE pathogens exhibit biphasic killing kinetics, indicative of persister formation. In vitro cycling between aminoglycoside killing and persister cell regrowth, evocative of clinical high-dose extended-interval therapy, caused a 37- to 213-fold increase in persistence without the emergence of resistance. Increased persistence also manifested in biofilms and provided cross-tolerance to different clinically important antibiotics. Together, our results highlight a possible drawback of intermittent, high-dose antibiotic therapy and suggest that clinical diagnostics might benefit from taking into account persistence. PMID:27185802

  11. Differences in pathogenicity of A/Duck/Vietnam/201/05 H5N1 highly pathogenic avian influenza virus reassortants in ducks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In order to understand which viral genes contribute to the high virulence of A/Dk/Vietnam/201/05 H5N1 highly pathogenic avian influenza (HPAI) virus in ducks, we used reverse genetics to generate single-gene reassortant viruses with genes from A/Ck/Indonesia/7/03, a virus that produces mild disease ...

  12. Gating of high-mobility InAs metamorphic heterostructures

    SciTech Connect

    Shabani, J.; McFadden, A. P.; Shojaei, B.; Palmstrøm, C. J.

    2014-12-29

    We investigate the performance of gate-defined devices fabricated on high mobility InAs metamorphic heterostructures. We find that heterostructures capped with In{sub 0.75}Ga{sub 0.25}As often show signs of parallel conduction due to proximity of their surface Fermi level to the conduction band minimum. Here, we introduce a technique that can be used to estimate the density of this surface charge that involves cool-downs from room temperature under gate bias. We have been able to remove the parallel conduction under high positive bias, but achieving full depletion has proven difficult. We find that by using In{sub 0.75}Al{sub 0.25}As as the barrier without an In{sub 0.75}Ga{sub 0.25}As capping, a drastic reduction in parallel conduction can be achieved. Our studies show that this does not change the transport properties of the quantum well significantly. We achieved full depletion in InAlAs capped heterostructures with non-hysteretic gating response suitable for fabrication of gate-defined mesoscopic devices.

  13. Multiple introductions of highly pathogenic avian influenza H5N1 viruses into Bangladesh

    PubMed Central

    Marinova-Petkova, Atanaska; Feeroz, Mohammed M; Rabiul Alam, SM; Kamrul Hasan, M; Akhtar, Sharmin; Jones-Engel, Lisa; Walker, David; McClenaghan, Laura; Rubrum, Adam; Franks, John; Seiler, Patrick; Jeevan, Trushar; McKenzie, Pamela; Krauss, Scott; Webby, Richard J; Webster, Robert G

    2014-01-01

    Highly pathogenic H5N1 and low pathogenic H9N2 influenza viruses are endemic to poultry markets in Bangladesh and have cocirculated since 2008. H9N2 influenza viruses circulated constantly in the poultry markets, whereas highly pathogenic H5N1 viruses occurred sporadically, with peaks of activity in cooler months. Thirty highly pathogenic H5N1 influenza viruses isolated from poultry were characterized by antigenic, molecular, and phylogenetic analyses. Highly pathogenic H5N1 influenza viruses from clades 2.2.2 and 2.3.2.1 were isolated from live bird markets only. Phylogenetic analysis of the 30 H5N1 isolates revealed multiple introductions of H5N1 influenza viruses in Bangladesh. There was no reassortment between the local H9N2 influenza viruses and H5N1 genotype, despite their prolonged cocirculation. However, we detected two reassortant H5N1 viruses, carrying the M gene from the Chinese H9N2 lineage, which briefly circulated in the Bangladesh poultry markets and then disappeared. On the other hand, interclade reassortment occurred within H5N1 lineages and played a role in the genesis of the currently dominant H5N1 viruses in Bangladesh. Few ‘human-like' mutations in H5N1 may account for the limited number of human cases. Antigenically, clade 2.3.2.1 H5N1 viruses in Bangladesh have evolved since their introduction and are currently mainly homogenous, and show evidence of recent antigenic drift. Although reassortants containing H9N2 genes were detected in live poultry markets in Bangladesh, these reassortants failed to supplant the dominant H5N1 lineage. PMID:26038508

  14. Highly pathogenic avian influenza virus (H5N1) in experimentally infected adult mute swans.

    PubMed

    Kalthoff, Donata; Breithaupt, Angele; Teifke, Jens P; Globig, Anja; Harder, Timm; Mettenleiter, Thomas C; Beer, Martin

    2008-08-01

    Adult, healthy mute swans were experimentally infected with highly pathogenic avian influenza virus A/Cygnus cygnus/Germany/R65/2006 subtype H5N1. Immunologically naive birds died, whereas animals with preexisting, naturally acquired avian influenza virus-specific antibodies became infected asymptomatically and shed virus. Adult mute swans are highly susceptible, excrete virus, and can be clinically protected by preexposure immunity. PMID:18680652

  15. Draft Genome Sequence of a Highly Virulent Strain of the Plant Pathogen Dickeya solani, IFB0099

    PubMed Central

    Golanowska, M.; Galardini, M.; Bazzicalupo, M.; Hugouvieux-Cotte-Pattat, N.; Mengoni, A.; Potrykus, M.; Slawiak, M.

    2015-01-01

    Dickeya solani is an important bacterial pathogen of potato cultivars in Europe. Here, we present the draft genome of D. solani strain IFB0099 isolated from potato in Poland that shows a high level of pectinolytic activity and a high virulence. This genome sequence is 5,094,121 bp and contains 4,365 protein-coding sequences. PMID:25792047

  16. Development of High Hydrostatic Pressure Applied in Pathogen Inactivation for Plasma

    PubMed Central

    Yang, Hong; Zhang, Xinmin; Chen, Limin; Wang, Jingxing

    2016-01-01

    High hydrostatic pressure has been used to inactivate pathogens in foods for decades. There is a great potential to adapt this technology to inactivate pathogens in plasma and derivatives. To better evaluate the potential of this method, pathogen inoculated plasma samples were pressurized under different pressure application modes and temperatures. The inactivation efficacy of pathogens and activities of plasma proteins were monitored after treatment. The CFUs of E.coli was examined as the indicator of the inactivation efficiency. The factor V and VIII were chosen as the indicator of the plasma function. Preliminary experiments identified optimized treatment conditions: 200-250MPa, with 5×1 minute multi-pulsed high pressure at near 0°C (ice-water bath). Under this conditions, the inactivation efficacy of EMCV was >8.5log. The CFUs of E. coli were reduced by 7.5log, B. cereus were 8log. However, PPV and S. aureus cannot be inactivated efficiently. The activities of factor II, VII, IX, X, XI, XII, fibrinogen, IgG, IgM stayed over 95% compared to untreated. Factor V and VIII activity was maintained at 46–63% and 77–82%, respectively. PMID:27561010

  17. Assessment of the Effects of Climate Change on the Mobility and Distribution of Metals and Pathogens at the River Basin Scale

    NASA Astrophysics Data System (ADS)

    Stergiadi, Maria; De Nijs, Ton; Sterk, Ankie; Van Der Perk, Marcel; Bierkens, Marc

    2013-04-01

    Anticipated climate change will most likely affect the mobility and distribution of contaminants, such as metals and pathogens, in soil, groundwater and surface water, ultimately affecting terrestrial and aquatic ecosystems, as well as public health. For example, temperature-induced changes in soil structure may affect species composition, thereby promoting the transport of toxic substances, such as copper and cadmium, and pathogenic microorganisms. In the framework of a project to assess the effects of climate change on the concentrations and fluxes of metals and pathogens at the catchment scale, a dynamic, spatially distributed River Basin Model that integrates catchment-scale transport models will be developed. The River Basin Model will consist of modules describing the transfers and feedbacks between the environmental compartments soil, groundwater and surface water. The innovative aspect of this project involves the development of a novel soil module to include the effects of changing soil organic matter content and composition on the speciation and transport pathways of contaminants. For this purpose, a point-scale soil organic matter and nutrient dynamics model will be linked to a chemical speciation and transport model, which allows a quantitative assessment of climate change effects on the mobility of metals and pathogens in various soil types. The results of this model analyses will be used to parameterize a large-scale soil module to be included in the river basin model. To assess the impact of climate change and changes in land use on the future distributions of contaminant concentrations in the major exposure pathways to man and ecosystems, a selected number of scenarios addressing climate change, agricultural practices (land use change, land management), current policies and mitigation strategies, will be defined. For each scenario, the River Basin Model will be used to project the probability distributions of contaminant concentrations in soil

  18. Age at infection affects the pathogenicity of Asian highly pathogenic avian influenza H5N1 viruses in ducks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian H5N1 avian influenza (AI) viruses have changed from producing no disease or mild respiratory infections in ducks to some strains causing systemic disease and death. Differences in pathogenicity between four of these viruses as well as the effect of host age on the outcome of infection were...

  19. A compact high resolution electrospray ionization ion mobility spectrometer.

    PubMed

    Reinecke, T; Kirk, A T; Ahrens, A; Raddatz, C-R; Thoben, C; Zimmermann, S

    2016-04-01

    Electrospray is a commonly used ionization method for the analysis of liquids. An electrospray is a dispersed nebular of charged droplets produced under the influence of a strong electrical field. Subsequently, ions are produced in a complex process initiated by evaporation of neutral solvent molecules from these droplets. We coupled an electrospray ionization source to our previously described high resolution ion mobility spectrometer with 75mm drift tube length and a drift voltage of 5kV. When using a tritium source for chemical gas phase ionization, a resolving power of R=100 was reported for this setup. We replaced the tritium source and the field switching shutter by an electrospray needle, a desolvation region with variable length and a three-grid shutter for injecting ions into the drift region. Preliminary measurements with tetraalkylammonium halides show that the current configuration with the electrospray ionization source maintains the resolving power of R=100. In this work, we present the characterization of our setup. One major advantage of our setup is that the desolvation region can be heated separately from the drift region so that the temperature in the drift region stays at room temperature even up to desolvation region temperatures of 100°C. We perform parametric studies for the investigation of the influence of temperature on solvent evaporation with different ratios of water and methanol in the solvent for different analyte substances. Furthermore, the setup is operated in negative mode and spectra of bentazon with different solvents are presented. PMID:26838374

  20. High-mobility group box 1 in multiple sclerosis.

    PubMed

    Sternberg, Zohara; Sternberg, Daniel; Chichelli, Trevor; Drake, Allison; Patel, Neel; Kolb, Chana; Chadha, Kailash; Yu, Jinhee; Hojnacki, David

    2016-04-01

    This study is one in series determining the potential of RAGE axis (receptor for advanced glycation end products, isoforms, ligands) as a biomarker in multiple sclerosis (MS). We evaluated serum levels of RAGE ligand, the high-mobility group box (HMGB)1 in MS patients, and assessed the correlation between HMGB1 serum levels and the use of disease-modifying drugs (DMDs), and between HMGB1 serum levels and indicators of MS disease severity. HMGB1 serum levels were compared between 96 (23 males) MS patients and 34 age- and gender-matched healthy controls (HCs) using enzyme-linked immunosorbent assays. DMD-naïve MS patients had significantly higher HMGB1 serum levels compared with DMD-treated (P = 0.04) and compared with HCs (P = 0.01). HMGB1 serum levels were not significantly different between total MS patients (DMD-naïve plus DMD-treated) and HCs (P = 0.09). DMD-naïve MS patients in clinical relapse tended to have lower HMGB1 serum levels than clinically stable RRMS patients (P = 0.07). HMGB1 serum levels showed 0.65 area under the curve (95 % CI 0.55-0.95) sensitivity/specificity for MS clinical relapse. The role of HMGB1 in MS disease pathology and DMD modulation of this protein warrant further investigations. PMID:26100980

  1. High-mobility group box-1 in sterile inflammation.

    PubMed

    Tsung, A; Tohme, S; Billiar, T R

    2014-11-01

    High-mobility group box 1 (HMGB1) was originally defined as a ubiquitous nuclear protein, but it was later determined that the protein has different roles both inside and outside of cells. Nuclear HMGB1 regulates chromatin structure and gene transcription, whereas cytosolic HMGB1 is involved in inflammasome activation and autophagy. Extracellular HMGB1 has drawn attention because it can bind to related cell signalling transduction receptors, such as the receptor for advanced glycation end products, Toll-like receptor (TLR)2, TLR4 and TLR9. It also participates in the development and progression of a variety of diseases. HMGB1 is actively secreted by stimulation of the innate immune system, and it is passively released by ischaemia or cell injury. This review focuses on the important role of HMGB1 in the pathogenesis of acute and chronic sterile inflammatory conditions. Strategies that target HMGB1 have been shown to significantly decrease inflammation in several disease models of sterile inflammation, and this may represent a promising clinical approach for treatment of certain conditions associated with sterile inflammation. PMID:24935761

  2. Chinese and Vietnamese strains of HP-PRRSV cause different pathogenic outcomes in United States high health swine

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An infectious clone of a highly pathogenic PRRSV strain from Vietnam (rSRV07) was prepared, analyzed and compared to Chinese highly pathogenic PRRSV rJXwn06 and US Type 2 prototype VR-2332 in order to examine the effects of virus phenotype and genotype on growth in MARC-145 cells, as well as the imp...

  3. Single vaccination provides limited protection to ducks and geese against H5N1 high pathogenicity avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since 2002, high pathogenicity avian influenza has spread from Asia to Europe and into Africa causing the largest epizootic of high pathogenicity avian influenza (HPAI) of the last 50 years including infecting domestic and wild waterfowl. Our study was conducted to investigate whether single vaccina...

  4. A Nuclear Factor of High Mobility Group Box Protein in Toxoplasma gondii

    PubMed Central

    Wang, Hui; Lei, Tao; Liu, Jing; Li, Muzi; Nan, Huizhu; Liu, Qun

    2014-01-01

    High mobility group box 1 (HMGB1) is a nuclear factor that usually binds DNA and modulates gene expression in multicellular organisms. Three HMGB1 orthologs were predicted in the genome of Toxoplasma gondii, an obligate intracellular protozoan pathogen, termed TgHMGB1a, b and c. Phylogenetic and bioinformatic analyses indicated that these proteins all contain a single HMG box and which shared in three genotypes. We cloned TgHMGB1a, a 33.9 kDa protein that can stimulates macrophages to release TNF-α, and, we demonstrated that the TgHMGB1a binds distorted DNA structures such as cruciform DNA in electrophoretic mobility shift assays (EMSA). Immunofluorescence assay indicated TgHMGB1a concentrated in the nucleus of intracellular tachyzoites but translocated into the cytoplasm while the parasites release to extracellular. There were no significant phenotypic changes when the TgHMGB1a B box was deleted, while transgenic parasites that overexpressed TgHMGB1a showed slower intracellular growth and caused delayed death in mouse, further quantitative RT-PCR analyses showed that the expression levels of many important genes, including virulence factors, increased when TgHMGB1a was overexpressed, but no significant changes were observed in TgHMGB1a B box-deficient parasites. Our findings demonstrated that TgHMGB1a is indeed a nuclear protein that maintains HMG box architectural functions and is a potential proinflammatory factor during the T.gondii infection. Further studies that clarify the functions of TgHMGB1s will increase our knowledge of transcriptional regulation and parasite virulence, and might provide new insight into host–parasite interactions for T. gondii infection. PMID:25369210

  5. [VERTEBRAL OSTEOMYELITIS CAUSED BY RARE PATHOGENS--THE NEED FOR HIGH INDEX OF SUSPICION].

    PubMed

    Lavie, Gil; Feldhaim, Michal; Weber, Gabriel; Cohen, Shai

    2015-06-01

    Vertebral OsteomyeLitis (V.O.) is a rare event that usually presents insidiously and follows an indolent clinical course, making early diagnosis difficult. The most important infecting organism in V.O. is Staphylococcus aureus, followed by gram-negative bacilli. We describe herein two cases of V.O. hospitalized in our department during the same week, caused by rare pathogens--Streptococcus sanguis (viridans) and Bacteroides fragilis. V.O. must be recognized rapidly because delay in diagnosis and treatment can result in neurologic compromise and high mortality. Its prompt and accurate diagnosis depends on detailed knowledge of the disease along with a high index of suspicion, even in face of rare pathogens on bacteriology results. PMID:26281078

  6. Wild bird surveillance for highly pathogenic avian influenza H5 in North America

    USGS Publications Warehouse

    Flint, Paul L.; Pearce, John M.; Franson, J. Christian; Derksen, Dirk V.

    2015-01-01

    It is unknown how the current Asian origin highly pathogenic avian influenza H5 viruses arrived, but these viruses are now poised to become endemic in North America. Wild birds harbor these viruses and have dispersed them at regional scales. What is unclear is how the viruses may be moving from the wild bird reservoir into poultry holdings. Active surveillance of live wild birds is likely the best way to determine the true distribution of these viruses. We also suggest that sampling be focused on regions with the greatest risk for poultry losses and attempt to define the mechanisms of transfer to enhance biosecurity. Responding to the recent outbreaks of highly pathogenic avian influenza in North America requires an efficient plan with clear objectives and potential management outcomes.

  7. 2.1 Natural History of Highly Pathogenic Avian Influenza H5N1

    PubMed Central

    Sonnberg, Stephanie; Webby, Richard J.; Webster, Robert G.

    2013-01-01

    The ecology of highly pathogenic avian influenza (HPAI) H5N1 has significantly changed from sporadic outbreaks in terrestrial poultry to persistent circulation in terrestrial and aquatic poultry and potentially in wild waterfowl. A novel genotype of HPAI H5N1 arose in 1996 in southern China and through ongoing mutation, reassortment, and natural selection, has diverged into distinct lineages and expanded into multiple reservoir hosts. The evolution of Goose/Guangdong-lineage highly pathogenic H5N1 viruses is ongoing: while stable interactions exist with some reservoir hosts, these viruses are continuing to evolve and adapt to others, and pose an un-calculable risk to sporadic hosts, including humans. PMID:23735535

  8. Potential strategies and biosafety protocols used for dual-use research on highly pathogenic influenza viruses

    PubMed Central

    Du, Lanying; Li, Ye; Gao, Jimin; Zhou, Yusen; Jiang, Shibo

    2013-01-01

    Summary Influenza A viruses (IAVs), particularly the highly pathogenic avian influenza (HPAI) H5N1, have posed a substantial threat to public health worldwide. Although the laboratory generation of the mutant influenza virus H5N1 with airborne transmissibility among mammals, which has been considered as a dual-use research, may benefit the development of effective vaccines and therapeutics against the emerging infectious agents, it may also pose threats to national biosecurity, laboratory biosafety, and/or public health. This review introduces the classification and characterization of IAVs, pinpoints historic pandemics and epidemics caused by IAVs, emphasizes the significance and necessity of biosafety, summarizes currently established biosafety-related protocols for IAV research, and provides potential strategies to improve biosafety protocols for dual-use research on the highly pathogenic avian influenza viruses and other emerging infectious agents. PMID:22987727

  9. Growth and Pathogenic Potential of Naturally Selected Reassortants after Coinfection with Pandemic H1N1 and Highly Pathogenic Avian Influenza H5N1 Viruses

    PubMed Central

    Song, Min-Suk; Baek, Yun Hee; Pascua, Philippe Noriel Q.; Kwon, Hyeok-il; Kim, Eun-Ha; Park, Su-Jin; Kim, Se Mi; Kim, Young-Il; Choi, Won-Suk; Kim, Eung-Gook; Kim, Chul-Joong

    2015-01-01

    Coinfection of ferrets with H5N1 and pH1N1 viruses resulted in two predominate genotypes in the lungs containing surface genes of highly pathogenic avian influenza H5N1 virus in the backbone of pandemic H1N1 2009 (pH1N1). Compared to parental strains, these reassortants exhibited increased growth and virulence in vitro and in mice but failed to be transmitted indirectly to naive contact ferrets. Thus, this demonstrates a possible natural reassortment following coinfection as well as the pathogenicity of the potential reassortants. PMID:26491154

  10. Growth and Pathogenic Potential of Naturally Selected Reassortants after Coinfection with Pandemic H1N1 and Highly Pathogenic Avian Influenza H5N1 Viruses.

    PubMed

    Song, Min-Suk; Baek, Yun Hee; Pascua, Philippe Noriel Q; Kwon, Hyeok-Il; Kim, Eun-Ha; Park, Su-Jin; Kim, Se Mi; Kim, Young-Il; Choi, Won-Suk; Kim, Eung-Gook; Kim, Chul-Joong; Choi, Young Ki

    2016-01-01

    Coinfection of ferrets with H5N1 and pH1N1 viruses resulted in two predominate genotypes in the lungs containing surface genes of highly pathogenic avian influenza H5N1 virus in the backbone of pandemic H1N1 2009 (pH1N1). Compared to parental strains, these reassortants exhibited increased growth and virulence in vitro and in mice but failed to be transmitted indirectly to naive contact ferrets. Thus, this demonstrates a possible natural reassortment following coinfection as well as the pathogenicity of the potential reassortants. PMID:26491154

  11. Differences in pathogenicity and response to vaccination between Pekin and Muscovy ducks infected with H5N1 highly pathogenic influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ducks have been implicated in the dissemination and evolution of H5N1 highly pathogenic avian influenza (HPAI) viruses. Vaccination of domestic ducks against H5N1 HPAI is being conducted as a method of control but with mixed results. One of the observations from the field is that Muscovy ducks (Cair...

  12. Assessment of national strategies for control of high pathogenicity avian influenza and low pathogenicity notifiable avian influenza in poultry, with emphasis on vaccines and vaccination

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Twenty-nine distinct epizootics of highly pathogenic avian influenza (HPAI) have occurred since 1959. The H5N1 HPAI panzootic affecting Asia, Africa and Eastern Europe has been the largest among these, affecting poultry and/or wild birds in 63 countries. Historically, control strategies have focus...

  13. Comparison of molecular classification and experimental pathogenicity for classification of low and high pathogenicity H5 and H7 avian influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Highly pathogenic avian influenza (HPAI) viruses, which have been restricted to H5 and H7 subtypes, have caused continuous outbreaks in the poultry industry with devastating economic losses and is a severe threat to public health. Genetic features and severity of the disease in poultry determine wh...

  14. Genetic characterization of highly pathogenic H5 influenza viruses from poultry in Taiwan, 2015.

    PubMed

    Huang, Pei-Yu; Lee, Chang-Chun David; Yip, Chun-Hung; Cheung, Chung-Lam; Yu, Guangchuang; Lam, Tommy Tsan-Yuk; Smith, David K; Zhu, Huachen; Guan, Yi

    2016-03-01

    Phylogenetic analysis of the highly pathogenic avian influenza (HPAI) H5 viruses causing recent outbreaks in Taiwan showed that they belonged to the Asian HPAI H5 lineage, clade 2.3.4.4 viruses, and were apparently introduced by migratory birds. These viruses reassorted with Eurasian influenza gene pool viruses and formed five genotypic variants. As Taiwan has a similar influenza ecosystem to southern China, the HPAI H5 lineage could become established and enzootic in the island. PMID:26690663

  15. Alterations in Hemagglutinin Receptor-Binding Specificity Accompany the Emergence of Highly Pathogenic Avian Influenza Viruses

    PubMed Central

    Mochalova, Larisa; Harder, Timm; Tuzikov, Alexander; Bovin, Nicolai; Wolff, Thorsten; Matrosovich, Mikhail; Schweiger, Brunhilde

    2015-01-01

    ABSTRACT Highly pathogenic avian influenza viruses (HPAIVs) of hemagglutinin H5 and H7 subtypes emerge after introduction of low-pathogenic avian influenza viruses (LPAIVs) from wild birds into poultry flocks, followed by subsequent circulation and evolution. The acquisition of multiple basic amino acids at the endoproteolytical cleavage site of the hemagglutinin (HA) is a molecular indicator for high pathogenicity, at least for infections of gallinaceous poultry. Apart from the well-studied significance of the multibasic HA cleavage site, there is only limited knowledge on other alterations in the HA and neuraminidase (NA) molecules associated with changes in tropism during the emergence of HPAIVs from LPAIVs. We hypothesized that changes in tropism may require alterations of the sialyloligosaccharide specificities of HA and NA. To test this hypothesis, we compared a number of LPAIVs and HPAIVs for their HA-mediated binding and NA-mediated desialylation of a set of synthetic receptor analogs, namely, α2-3-sialylated oligosaccharides. NA substrate specificity correlated with structural groups of NAs and did not correlate with pathogenic potential of the virus. In contrast, all HPAIVs differed from LPAIVs by a higher HA receptor-binding affinity toward the trisaccharides Neu5Acα2-3Galβ1-4GlcNAcβ (3′SLN) and Neu5Acα2-3Galβ1-3GlcNAcβ (SiaLec) and by the ability to discriminate between the nonfucosylated and fucosylated sialyloligosaccharides 3′SLN and Neu5Acα2-3Galβ1-4(Fucα1-3)GlcNAcβ (SiaLex), respectively. These results suggest that alteration of the receptor-binding specificity accompanies emergence of the HPAIVs from their low-pathogenic precursors. IMPORTANCE Here, we have found for the first time correlations of receptor-binding properties of the HA with a highly pathogenic phenotype of poultry viruses. Our study suggests that enhanced receptor-binding affinity of HPAIVs for a typical “poultry-like” receptor, 3′SLN, is provided by

  16. High Speed Mobility Through On-Demand Aviation

    NASA Technical Reports Server (NTRS)

    Moore, Mark D.; Goodrich, Ken; Viken, Jeff; Smith, Jeremy; Fredericks, Bill; Trani, Toni; Barraclough, Jonathan; German, Brian; Patterson, Michael

    2013-01-01

    automobiles. ?? Community Noise: Hub and smaller GA airports are facing increasing noise restrictions, and while commercial airliners have dramatically decreased their community noise footprint over the past 30 years, GA aircraft noise has essentially remained same, and moreover, is located in closer proximity to neighborhoods and businesses. ?? Operating Costs: GA operating costs have risen dramatically due to average fuel costs of over $6 per gallon, which has constrained the market over the past decade and resulted in more than 50% lower sales and 35% less yearly operations. Infusion of autonomy and electric propulsion technologies can accomplish not only a transformation of the GA market, but also provide a technology enablement bridge for both larger aircraft and the emerging civil Unmanned Aerial Systems (UAS) markets. The NASA Advanced General Aviation Transport Experiments (AGATE) project successfully used a similar approach to enable the introduction of primary composite structures and flat panel displays in the 1990s, establishing both the technology and certification standardization to permit quick adoption through partnerships with industry, academia, and the Federal Aviation Administration (FAA). Regional and airliner markets are experiencing constant pressure to achieve decreasing levels of community emissions and noise, while lowering operating costs and improving safety. But to what degree can these new technology frontiers impact aircraft safety, the environment, operations, cost, and performance? Are the benefits transformational enough to fundamentally alter aircraft competiveness and productivity to permit much greater aviation use for high speed and On-Demand Mobility (ODM)? These questions were asked in a Zip aviation system study named after the Zip Car, an emerging car-sharing business model. Zip Aviation investigates the potential to enable new emergent markets for aviation that offer "more flexibility than the existing transportation solutions

  17. Characaterization of H5N1 highly pathogenic avian influenza viruses isolated from poultry in Pakistan 2006-2008

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Nine avian influenza viruses (AIV), H5N1 subtype, were isolated from dead poultry in the Karachi region of Pakistan from 2006-2008. The intravenous pathogenicity indices and HA protein cleavage sites of all nine viruses were consistent with highly pathogenic AIV. Based on phylogenetic analysis of ...

  18. Innate immune responses to infection with H5N1 highly pathogenic avian influenza virus in different duck species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ducks have been implicated in the dissemination and evolution of H5N1 highly pathogenic avian influenza (HPAI) viruses. Differences in pathogenicity and response to vaccination have been observed between different duck species. The innate immune system is responsible for controlling viruses during t...

  19. Survivability of Eurasian H5N1 highly pathogenic avian influenza viruses in water varies between strains

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Aquatic habitats play critical role in the transmission and maintenance of low pathogenic avian influenza (LPAI) viruses in wild waterfowl; however the importance of these environments in the ecology of H5N1 highly pathogenic avian influenza (HPAI) viruses is unknown. In laboratory-based studies, L...

  20. Experimental infection of mallard ducks with different subtype H5 and H7 highly pathogenic avian influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Highly pathogenic avian influenza viruses (HPAIV’s) remain a threat to poultry worldwide. Avian influenza viruses, including HPAIV, are usually non-pathogenic for ducks and other wild aquatic birds, with the exception of some Asian lineage H5N1 HPAIVs which can cause severe disease in ducks. With ...

  1. Infection of United States swine with a Chinese highly pathogenic strain of porcine reproductive and respiratory syndrome virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To assess the pathogenic effects of Type 2 highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) on healthy 10-week old commercial swine in the United States, viral kinetics and resultant disease caused by intranasal inoculation of such virus rescued from an infectious clo...

  2. Within-Host Models of High and Low Pathogenic Influenza Virus Infections: The Role of Macrophages.

    PubMed

    Pawelek, Kasia A; Dor, Daniel; Salmeron, Cristian; Handel, Andreas

    2016-01-01

    The World Health Organization identifies influenza as a major public health problem. While the strains commonly circulating in humans usually do not cause severe pathogenicity in healthy adults, some strains that have infected humans, such as H5N1, can cause high morbidity and mortality. Based on the severity of the disease, influenza viruses are sometimes categorized as either being highly pathogenic (HP) or having low pathogenicity (LP). The reasons why some strains are LP and others HP are not fully understood. While there are likely multiple mechanisms of interaction between the virus and the immune response that determine LP versus HP outcomes, we focus here on one component, namely macrophages (MP). There is some evidence that MP may both help fight the infection and become productively infected with HP influenza viruses. We developed mathematical models for influenza infections which explicitly included the dynamics and action of MP. We fit these models to viral load and macrophage count data from experimental infections of mice with LP and HP strains. Our results suggest that MP may not only help fight an influenza infection but may contribute to virus production in infections with HP viruses. We also explored the impact of combination therapies with antivirals and anti-inflammatory drugs on HP infections. Our study suggests a possible mechanism of MP in determining HP versus LP outcomes, and how different interventions might affect infection dynamics. PMID:26918620

  3. Isolation and characterization of highly pathogenic avian influenza virus subtype H5N1 from donkeys

    PubMed Central

    2010-01-01

    Background The highly pathogenic H5N1 is a major avian pathogen that crosses species barriers and seriously affects humans as well as some mammals. It mutates in an intensified manner and is considered a potential candidate for the possible next pandemic with all the catastrophic consequences. Methods Nasal swabs were collected from donkeys suffered from respiratory distress. The virus was isolated from the pooled nasal swabs in specific pathogen free embryonated chicken eggs (SPF-ECE). Reverse transcriptase polymerase chain reaction (RT-PCR) and sequencing of both haemagglutingin and neuraminidase were performed. H5 seroconversion was screened using haemagglutination inhibition (HI) assay on 105 donkey serum samples. Results We demonstrated that H5N1 jumped from poultry to another mammalian host; donkeys. Phylogenetic analysis showed that the virus clustered within the lineage of H5N1 from Egypt, closely related to 2009 isolates. It harboured few genetic changes compared to the closely related viruses from avian and humans. The neuraminidase lacks oseltamivir resistant mutations. Interestingly, HI screening for antibodies to H5 haemagglutinins in donkeys revealed high exposure rate. Conclusions These findings extend the host range of the H5N1 influenza virus, possess implications for influenza virus epidemiology and highlight the need for the systematic surveillance of H5N1 in animals in the vicinity of backyard poultry units especially in endemic areas. PMID:20398268

  4. Within-Host Models of High and Low Pathogenic Influenza Virus Infections: The Role of Macrophages

    PubMed Central

    Pawelek, Kasia A.; Dor, Daniel; Salmeron, Cristian; Handel, Andreas

    2016-01-01

    The World Health Organization identifies influenza as a major public health problem. While the strains commonly circulating in humans usually do not cause severe pathogenicity in healthy adults, some strains that have infected humans, such as H5N1, can cause high morbidity and mortality. Based on the severity of the disease, influenza viruses are sometimes categorized as either being highly pathogenic (HP) or having low pathogenicity (LP). The reasons why some strains are LP and others HP are not fully understood. While there are likely multiple mechanisms of interaction between the virus and the immune response that determine LP versus HP outcomes, we focus here on one component, namely macrophages (MP). There is some evidence that MP may both help fight the infection and become productively infected with HP influenza viruses. We developed mathematical models for influenza infections which explicitly included the dynamics and action of MP. We fit these models to viral load and macrophage count data from experimental infections of mice with LP and HP strains. Our results suggest that MP may not only help fight an influenza infection but may contribute to virus production in infections with HP viruses. We also explored the impact of combination therapies with antivirals and anti-inflammatory drugs on HP infections. Our study suggests a possible mechanism of MP in determining HP versus LP outcomes, and how different interventions might affect infection dynamics. PMID:26918620

  5. High-Throughput Screening of a Diversity Collection Using Biodefense Category A and B Priority Pathogens

    PubMed Central

    Barrow, Esther W.; Clinkenbeard, Patricia A.; Duncan-Decocq, Rebecca A.; Perteet, Rachel F.; Hill, Kimberly D.; Bourne, Philip C.; Valderas, Michelle W.; Bourne, Christina R.; Clarkson, Nicole L.; Clinkenbeard, Kenneth D.; Barrow, William W.

    2013-01-01

    One of the objectives of the National Institutes of Allergy and Infectious Diseases (NIAID) Biodefense Program is to identify or develop broad-spectrum antimicrobials for use against bioterrorism pathogens and emerging infectious agents. As a part of that program, our institution has screened the 10 000-compound MyriaScreen Diversity Collection of high-purity druglike compounds against three NIAID category A and one category B priority pathogens in an effort to identify potential compound classes for further drug development. The effective use of a Clinical and Laboratory Standards Institute–based high-throughput screening (HTS) 96-well–based format allowed for the identification of 49 compounds that had in vitro activity against all four pathogens with minimum inhibitory concentration values of ≤16 μg/mL. Adaptation of the HTS process was necessary to conduct the work in higher-level containment, in this case, biosafety level 3. Examination of chemical scaffolds shared by some of the 49 compounds and assessment of available chemical databases indicates that several may represent broad-spectrum antimicrobials whose activity is based on novel mechanisms of action. PMID:22653912

  6. International biosecurity symposium : securing high consequence pathogens and toxins : symposium summary.

    SciTech Connect

    Not Available

    2004-06-01

    The National Nuclear Security Administration (NNSA) Office of Nonproliferation Policy sponsored an international biosecurity symposium at Sandia National Laboratories (SNL). The event, entitled 'Securing High Consequence Pathogens and Toxins', took place from February 1 to February 6, 2004 and was hosted by Dr. Reynolds M. Salerno, Principal Member of the Technical Staff and Program Manager of the Biosecurity program at Sandia. Over 60 bioscience and policy experts from 14 countries gathered to discuss biosecurity, a strategy aimed at preventing the theft and sabotage of dangerous pathogens and toxins from bioscience facilities. Presentations delivered during the symposium were interspersed with targeted discussions that elucidated, among other things, the need for subsequent regional workshops on biosecurity, and a desire for additional work toward developing international biosecurity guidelines.

  7. Comparative Genomic Analysis Reveals a Possible Novel Non-Tuberculous Mycobacterium Species with High Pathogenic Potential

    PubMed Central

    Choo, Siew Woh; Dutta, Avirup; Wong, Guat Jah; Wee, Wei Yee; Ang, Mia Yang; Siow, Cheuk Chuen

    2016-01-01

    Mycobacteria have been reported to cause a wide range of human diseases. We present the first whole-genome study of a Non-Tuberculous Mycobacterium, Mycobacterium sp. UM_CSW (referred to hereafter as UM_CSW), isolated from a patient diagnosed with bronchiectasis. Our data suggest that this clinical isolate is likely a novel mycobacterial species, supported by clear evidence from molecular phylogenetic, comparative genomic, ANI and AAI analyses. UM_CSW is closely related to the Mycobacterium avium complex. While it has characteristic features of an environmental bacterium, it also shows a high pathogenic potential with the presence of a wide variety of putative genes related to bacterial virulence and shares very similar pathogenomic profiles with the known pathogenic mycobacterial species. Thus, we conclude that this possible novel Mycobacterium species should be tightly monitored for its possible causative role in human infections. PMID:27035710

  8. Highly Pathogenic Avian Influenza H5N8 in Germany: Outbreak Investigations.

    PubMed

    Conraths, F J; Sauter-Louis, C; Globig, A; Dietze, K; Pannwitz, G; Albrecht, K; Höreth-Böntgen, D; Beer, M; Staubach, C; Homeier-Bachmann, T

    2016-02-01

    Epidemiological outbreak investigations were conducted in highly pathogenic avian influenza virus of the subtype H5N8 (HPAIV H5N8)-affected poultry holdings and a zoo to identify potential routes of entry of the pathogen via water, feedstuffs, animals, people, bedding material, other fomites (equipment, vehicles etc.) and the presence of wild birds near affected holdings. Indirect introduction of HPAIV H5N8 via material contaminated by infected wild bird seems the most reasonable explanation for the observed outbreak series in three commercial holdings in Mecklenburg-Western Pomerania and Lower Saxony, while direct contact to infected wild birds may have led to outbreaks in a zoo in Rostock and in two small free-range holdings in Anklam, Mecklenburg-Western Pomerania. PMID:26519355

  9. Mobile elements and mitochondrial genome expansion in the soil fungus and potato pathogen Rhizoctonia solani AG-3.

    PubMed

    Losada, Liliana; Pakala, Suman B; Fedorova, Natalie D; Joardar, Vinita; Shabalina, Svetlana A; Hostetler, Jessica; Pakala, Suchitra M; Zafar, Nikhat; Thomas, Elizabeth; Rodriguez-Carres, Marianela; Dean, Ralph; Vilgalys, Rytas; Nierman, William C; Cubeta, Marc A

    2014-03-01

    The soil fungus Rhizoctonia solani is an economically important pathogen of agricultural and forestry crops. Here, we present the complete sequence and analysis of the mitochondrial genome of R. solani, field isolate Rhs1AP. The genome (235 849 bp) is the largest mitochondrial genome of a filamentous fungus sequenced to date and exhibits a rich accumulation of introns, novel repeat sequences, homing endonuclease genes, and hypothetical genes. Stable secondary structures exhibited by repeat sequences suggest that they comprise functional, possibly catalytic RNA elements. RNA-Seq expression profiling confirmed that the majority of homing endonuclease genes and hypothetical genes are transcriptionally active. Comparative analysis suggests that the mitochondrial genome of R. solani is an example of a dynamic history of expansion in filamentous fungi. PMID:24461055

  10. Pathogenicity and tissue tropism of currently circulating highly pathogenic avian influenza A virus (H5N1; clade 2.3.2) in tufted ducks (Aythya fuligula).

    PubMed

    Bröjer, Caroline; van Amerongen, Geert; van de Bildt, Marco; van Run, Peter; Osterhaus, Albert; Gavier-Widén, Dolores; Kuiken, Thijs

    2015-11-18

    Reports describing the isolation of highly pathogenic avian influenza (HPAI) virus (H5N1) clade 2.3.2 in feces from apparently healthy wild birds and the seemingly lower pathogenicity of this clade compared to clade 2.2 in several experimentally infected species, caused concern that the new clade might be maintained in the wild bird population. To investigate whether the pathogenicity of a clade 2.3.2 virus was lower than that of clades previously occurring in free-living wild birds in Europe, four tufted ducks were inoculated with influenza A/duck/HongKong/1091/2011 (H5N1) clade 2.3.2 virus. The ducks were monitored and sampled for virus excretion daily during 4 days, followed by pathologic, immunohistochemical, and virological investigations. The virus produced severe disease as evidenced by clinical signs, presence of marked lesions and abundant viral antigen in several tissues, especially the central nervous system. The study shows that HPAI-H5N1 virus clade 2.3.2 is highly pathogenic for tufted ducks and thus, they are unlikely to maintain this clade in the free-living population or serve as long-distance vectors. PMID:26441012

  11. Career Mobility of High-Flying Women Academics: A Study at Selected Universities in Malaysia

    ERIC Educational Resources Information Center

    Ismail, Maimunah; Rasdi, Roziah Mohd

    2006-01-01

    This study aims to investigate the relationship between past experience and the career mobility of 31 high-flying female academics from eight established Malaysian universities. Based on data gathered from in-depth interviews, it is discerned that the respondents' career mobility at the "exploration" stage is influenced by early exposure to…

  12. Investigating the Effectiveness of a Comprehensive Literacy Coaching Program in Schools with High Teacher Mobility

    ERIC Educational Resources Information Center

    Matsumura, Lindsay Clare; Garnier, Helen E.; Correnti, Richard; Junker, Brian; Bickel, Donna DiPrima

    2010-01-01

    Teacher mobility is a factor that impacts schoolwide implementation of professional development programs. In this article, we present interim results of a longitudinal randomized field trial of a comprehensive literacy coaching program (Content-Focused Coaching, CFC) for improving instruction and learning in schools with high teacher mobility. We…

  13. The design of a linear L-band high power amplifier for mobile communication satellites

    NASA Technical Reports Server (NTRS)

    Whittaker, N.; Brassard, G.; Li, E.; Goux, P.

    1990-01-01

    A linear L-band solid state high power amplifier designed for the space segment of the Mobile Satellite (MSAT) mobile communication system is described. The amplifier is capable of producing 35 watts of RF power with multitone signal at an efficiency of 25 percent and with intermodulation products better than 16 dB below carrier.

  14. Inhibition of Growth of Highly Resistant Bacterial and Fungal Pathogens by a Natural Product

    PubMed Central

    Hafidh, Rand R; Abdulamir, Ahmed S; Vern, Law Se; Abu Bakar, Fatimah; Abas, Faridah; Jahanshiri, Fatemeh; Sekawi, Zamberi

    2011-01-01

    The continuous escalation of resistant bacteria against a wide range of antibiotics necessitates discovering novel unconventional sources of antibiotics. B. oleracea L (red cabbage) is health-promoting food with proven anticancer and anti-inflammatory activities. However, it has not been researched adequately for its antimicrobial activity on potential resistant pathogens. The methanol crude extract of B. oleracea L. was investigated for a possible anti-microbial activity. The screening method was conducted using disc diffusion assay against 22 pathogenic bacteria and fungi. It was followed by evaluation of the minimum inhibitory concentration (MIC). Moreover, the antibacterial and the antifungal activities were confirmed using the minimum bactericidal concentration (MBC) and the minimum fungicidal concentration (MFC), respectively. Remarkable, antibacterial activity was evident particularly against highly infectious microorganisms such as Methicillin-resistant Staphylococcus aureus, Escherichia coli O157:H7, Pseudomonas aeruginosa, Klebsiella pneumoniae, Staphylococcus aureus, and Salmonella enterica serovar Typhimurium as well as against human fungal pathogens, Trichophyton rubrum and Aspergillus terreus. Red cabbage is a rich source of phenolic compounds, anthocyanins being the most abundant class, which might explain its potent antimicrobial action. This extract is potentially novel for future antimicrobials, inexpensive, and readily available at a large scale for pharmaceutical companies for further investigation and processing. PMID:21915230

  15. Dynamics of low and high pathogenic avian influenza in wild and domestic bird populations.

    PubMed

    Tuncer, Necibe; Torres, Juan; Martcheva, Maia; Barfield, Michael; Holt, Robert D

    2016-01-01

    This paper introduces a time-since-recovery structured, multi-strain, multi-population model of avian influenza. Influenza A viruses infect many species of wild and domestic birds and are classified into two groups based on their ability to cause disease: low pathogenic avian influenza (LPAI) and high pathogenic avian influenza (HPAI). Prior infection with LPAI provides partial immunity towards HPAI. The model introduced in this paper structures LPAI-recovered birds (wild and domestic) with time-since-recovery and includes cross-immunity towards HPAI that can fade with time. The model has a unique disease-free equilibrium (DFE), unique LPAI-only and HPAI-only equilibria and at least one coexistence equilibrium. We compute the reproduction numbers of LPAI ([Formula: see text]) and HPAI ([Formula: see text]) and show that the DFE is locally asymptotically stable when [Formula: see text] and [Formula: see text]. A unique LPAI-only (HPAI-only) equilibrium exists when [Formula: see text] ([Formula: see text]) and it is locally asymptotically stable if HPAI (LPAI) cannot invade the equilibrium, that is, if the invasion number [Formula: see text] ([Formula: see text]). We show using numerical simulations that the ODE version of the model, which is obtained by discarding the time-since-recovery structures (making cross-immunity constant), can exhibit oscillations, and also that the pathogens LPAI and HPAI can coexist with sustained oscillations in both populations. Through simulations, we show that even if both populations (wild and domestic) are sinks when alone, LPAI and HPAI can persist in both populations combined. Thus, reducing the reproduction numbers of LPAI and HPAI in each population to below unity is not enough to eradicate the disease. The pathogens can continue to coexist in both populations unless transmission between the populations is reduced. PMID:26667351

  16. Pathogenicity of H5N8 highly pathogenic avian influenza viruses isolated from a wild bird fecal specimen and a chicken in Japan in 2014.

    PubMed

    Tanikawa, Taichiro; Kanehira, Katsushi; Tsunekuni, Ryota; Uchida, Yuko; Takemae, Nobuhiro; Saito, Takehiko

    2016-04-01

    Poultry outbreaks caused by H5N8 highly pathogenic avian influenza viruses (HPAIVs) occurred in Japan between December 2014 and January 2015. During the same period; H5N8 HPAIVs were isolated from wild birds and the environment in Japan. The hemagglutinin (HA) genes of these isolates were found to belong to clade 2.3.4.4 and three sub-groups were distinguishable within this clade. All of the Japanese isolates from poultry outbreaks belonged to the same sub-group; whereas wild bird isolates belonged to the other sub-groups. To examine whether the difference in pathogenicity to chickens between isolates of different HA sub-groups of clade 2.3.4.4 could explain why the Japanese poultry outbreaks were only caused by a particular sub-group; pathogenicities of A/chicken/Miyazaki/7/2014 (Miyazaki2014; sub-group C) and A/duck/Chiba/26-372-48/2014 (Chiba2014; sub-group A) to chickens were compared and it was found that the lethality of Miyazaki2014 in chickens was lower than that of Chiba2014; according to the 50% chicken lethal dose. This indicated that differences in pathogenicity may not explain why the Japanese poultry outbreaks only involved group C isolates. PMID:26916882

  17. General strategy for self-assembly of highly oriented nanocrystalline semiconducting polymers with high mobility.

    PubMed

    Luo, Chan; Kyaw, Aung Ko Ko; Perez, Louis A; Patel, Shrayesh; Wang, Ming; Grimm, Bruno; Bazan, Guillermo C; Kramer, Edward J; Heeger, Alan J

    2014-05-14

    Solution processable semiconducting polymers with excellent film forming capacity and mechanical flexibility are considered among the most progressive alternatives to conventional inorganic semiconductors. However, the random packing of polymer chains and the disorder of the polymer matrix typically result in low charge transport mobilities (10(-5)-10(-2) cm(2) V(-1) s(-1)). These low mobilities compromise their performance and development. Here, we present a strategy, by utilizing capillary action, to mediate polymer chain self-assembly and unidirectional alignment on nanogrooved substrates. We designed a sandwich tunnel system separated by functionalized glass spacers to induce capillary action for controlling the polymer nanostructure, crystallinity, and charge transport. Using capillary action, we demonstrate saturation mobilities with average values of 21.3 and 18.5 cm(2) V(-1 )s(-1) on two different semiconducting polymers at a transistor channel length of 80 μm. These values are limited by the source-drain contact resistance, Rc. Using a longer channel length of 140 μm where the contact resistance is less important, we measured μh = 36.3 cm(2) v(-1) s(-1). Extrapolating to infinite channel length where Rc is unimportant, the intrinsic mobility for poly[4-(4,4-dihexadecyl-4H-cyclopenta[1,2-b:5,4-b']dithiophen-2-yl)-alt-[1,2,5]thiadiazolo[3,4-c]pyridine] (Mn = 140 kDa) at this degree of chain alignment and structural order is μh ≈ 47 cm(2 )v(-1) s(-1). Our results create a promising pathway toward high performance, solution processable, and low-cost organic electronics. PMID:24712578

  18. High-Speed Mobile Communications in Hostile Environments

    NASA Astrophysics Data System (ADS)

    Agosta, S.; Sierra, R.; Chapron, F.

    2015-12-01

    With the inexorable increase in the use of mobile devices, wireless connectivity is expected by users anywhere, anytime. In general, this requirement is addressed in office buildings or public locations through the use of Wi-Fi technology but Wi-Fi is not well adapted for use in large experiment halls and complex underground environments, especially those where radiation exposure is an issue, such as the LHC tunnel and experimental caverns. 4G/LTE technology, however, looks to be well adapted to addressing mobility needs in such areas. We report here the studies CERN has undertaken on the use of 4G/LTE in the LHC tunnel, presenting results on the data throughput that can be achieved and discussing issues such as the provision of a consistent user experience.

  19. Recombination, decreased host specificity and increased mobility may have driven the emergence of maize streak virus as an agricultural pathogen.

    PubMed

    Varsani, Arvind; Shepherd, Dionne N; Monjane, Adérito L; Owor, Betty E; Erdmann, Julia B; Rybicki, Edward P; Peterschmitt, Michel; Briddon, Rob W; Markham, Peter G; Oluwafemi, Sunday; Windram, Oliver P; Lefeuvre, Pierre; Lett, Jean-Michel; Martin, Darren P

    2008-09-01

    Maize streak virus (MSV; family Geminiviridae, genus Mastrevirus), the causal agent of maize streak disease, ranks amongst the most serious biological threats to food security in subSaharan Africa. Although five distinct MSV strains have been currently described, only one of these - MSV-A - causes severe disease in maize. Due primarily to their not being an obvious threat to agriculture, very little is known about the 'grass-adapted' MSV strains, MSV-B, -C, -D and -E. Since comparing the genetic diversities, geographical distributions and natural host ranges of MSV-A with the other MSV strains could provide valuable information on the epidemiology, evolution and emergence of MSV-A, we carried out a phylogeographical analysis of MSVs found in uncultivated indigenous African grasses. Amongst the 83 new MSV genomes presented here, we report the discovery of six new MSV strains (MSV-F to -K). The non-random recombination breakpoint distributions detectable with these and other available mastrevirus sequences partially mirror those seen in begomoviruses, implying that the forces shaping these breakpoint patterns have been largely conserved since the earliest geminivirus ancestors. We present evidence that the ancestor of all MSV-A variants was the recombinant progeny of ancestral MSV-B and MSV-G/-F variants. While it remains unknown whether recombination influenced the emergence of MSV-A in maize, our discovery that MSV-A variants may both move between and become established in different regions of Africa with greater ease, and infect more grass species than other MSV strains, goes some way towards explaining why MSV-A is such a successful maize pathogen. PMID:18753214

  20. Highly Pathogenic Leptospira Found in Urban Brown Rats (Rattus norvegicus) in the Largest Cities of Sweden.

    PubMed

    Strand, Tanja M; Löhmus, Mare; Persson Vinnersten, Thomas; Råsbäck, Therese; Sundström, Karin; Bergström, Tomas; Lundkvist, Åke

    2015-12-01

    Leptospirosis is an emerging zoonosis of global concern; however, its contemporary occurrence in Sweden, a European country partly located north of the Arctic Circle, is poorly known. Four out of 30 brown rats, captured within urban districts in Sweden, were found to be positive for antibodies to Leptospira interrogans serovar Icterohaemorrhagiae. This serovar causes Weil's disease in humans, a severe infection with jaundice, renal failure, and hemorrhage. Our study is the first finding of this highly pathogenic serovar in Swedish rats since the 1930s. PMID:26579782

  1. Remarkably high mobility ultra-thin-film metal-oxide transistor with strongly overlapped orbitals

    PubMed Central

    Wei Shih, Chen; Chin, Albert; Fu Lu, Chun; Fang Su, Wei

    2016-01-01

    High mobility channel thin-film-transistor (TFT) is crucial for both display and future generation integrated circuit. We report a new metal-oxide TFT that has an ultra-thin 4.5 nm SnO2 thickness for both active channel and source-drain regions, very high 147 cm2/Vs field-effect mobility, high ION/IOFF of 2.3 × 107, small 110 mV/dec sub-threshold slope, and a low VD of 2.5 V for low power operation. This mobility is already better than chemical-vapor-deposition grown multi-layers MoS2 TFT. From first principle quantum-mechanical calculation, the high mobility TFT is due to strongly overlapped orbitals. PMID:26744240

  2. Remarkably high mobility ultra-thin-film metal-oxide transistor with strongly overlapped orbitals

    NASA Astrophysics Data System (ADS)

    Wei Shih, Chen; Chin, Albert; Fu Lu, Chun; Fang Su, Wei

    2016-01-01

    High mobility channel thin-film-transistor (TFT) is crucial for both display and future generation integrated circuit. We report a new metal-oxide TFT that has an ultra-thin 4.5 nm SnO2 thickness for both active channel and source-drain regions, very high 147 cm2/Vs field-effect mobility, high ION/IOFF of 2.3 × 107, small 110 mV/dec sub-threshold slope, and a low VD of 2.5 V for low power operation. This mobility is already better than chemical-vapor-deposition grown multi-layers MoS2 TFT. From first principle quantum-mechanical calculation, the high mobility TFT is due to strongly overlapped orbitals.

  3. High-mobility ambipolar ZnO-graphene hybrid thin film transistors

    PubMed Central

    Song, Wooseok; Kwon, Soon Yeol; Myung, Sung; Jung, Min Wook; Kim, Seong Jun; Min, Bok Ki; Kang, Min-A; Kim, Sung Ho; Lim, Jongsun; An, Ki-Seok

    2014-01-01

    In order to combine advantages of ZnO thin film transistors (TFTs) with a high on-off ratio and graphene TFTs with extremely high carrier mobility, we present a facile methodology for fabricating ZnO thin film/graphene hybrid two-dimensional TFTs. Hybrid TFTs exhibited ambipolar behavior, an outstanding electron mobility of 329.7 ± 16.9 cm2/V·s, and a high on-off ratio of 105. The ambipolar behavior of the ZnO/graphene hybrid TFT with high electron mobility could be due to the superimposed density of states involving the donor states in the bandgap of ZnO thin films and the linear dispersion of monolayer graphene. We further established an applicable circuit model for understanding the improvement in carrier mobility of ZnO/graphene hybrid TFTs. PMID:24513629

  4. Remarkably high mobility ultra-thin-film metal-oxide transistor with strongly overlapped orbitals.

    PubMed

    Shih, Chen Wei; Chin, Albert; Lu, Chun Fu; Su, Wei Fang

    2016-01-01

    High mobility channel thin-film-transistor (TFT) is crucial for both display and future generation integrated circuit. We report a new metal-oxide TFT that has an ultra-thin 4.5 nm SnO2 thickness for both active channel and source-drain regions, very high 147 cm(2)/Vs field-effect mobility, high ION/IOFF of 2.3 × 10(7), small 110 mV/dec sub-threshold slope, and a low VD of 2.5 V for low power operation. This mobility is already better than chemical-vapor-deposition grown multi-layers MoS2 TFT. From first principle quantum-mechanical calculation, the high mobility TFT is due to strongly overlapped orbitals. PMID:26744240

  5. Utilization of a buffered dielectric to achieve high field-effect carrier mobility in graphene transistors.

    PubMed

    Farmer, Damon B; Chiu, Hsin-Ying; Lin, Yu-Ming; Jenkins, Keith A; Xia, Fengnian; Avouris, Phaedon

    2009-12-01

    We utilize an organic polymer buffer layer between graphene and conventional gate dielectrics in top-gated graphene transistors. Unlike other insulators, this dielectric stack does not significantly degrade carrier mobility, allowing for high field-effect mobilities to be retained in top-gate operation. This is demonstrated in both two-point and four-point analysis and in the high-frequency operation of a graphene transistor. Temperature dependence of the carrier mobility suggests that phonons are the dominant scatterers in these devices. PMID:19883119

  6. Band-like transport, high electron mobility and high photoconductivity in all-inorganic nanocrystal arrays.

    PubMed

    Lee, Jong-Soo; Kovalenko, Maksym V; Huang, Jing; Chung, Dae Sung; Talapin, Dmitri V

    2011-06-01

    Flexible, thin-film electronic and optoelectronic devices typically involve a trade-off between performance and fabrication cost. For example, solution-based deposition allows semiconductors to be patterned onto large-area substrates to make solar cells and displays, but the electron mobility in solution-deposited semiconductor layers is much lower than in semiconductors grown at high temperatures from the gas phase. Here, we report band-like electron transport in arrays of colloidal cadmium selenide nanocrystals capped with the molecular metal chalcogenide complex In(2)Se(4)(2-), and measure electron mobilities as high as 16 cm(2) V(-1) s(-1), which is about an order of magnitude higher than in the best solution-processed organic and nanocrystal devices so far. We also use CdSe/CdS core-shell nanoparticles with In(2)Se(4)(2-) ligands to build photodetectors with normalized detectivity D* > 1 × 10(13) Jones (I Jones = 1 cm Hz(1/2) W(-1)), which is a record for II-VI nanocrystals. Our approach does not require high processing temperatures, and can be extended to different nanocrystals and inorganic surface ligands. PMID:21516091

  7. Immune responses to modified live virus vaccines developed from classical or highly pathogenic PRRSV following challenge with a highly pathogenic PRRSV strain.

    PubMed

    Wang, Gang; Yu, Ying; Zhang, Chong; Tu, Yabin; Tong, Jie; Liu, Yonggang; Chang, Yafei; Jiang, Chenggang; Wang, Shujie; Zhou, En-Min; Cai, Xuehui

    2016-09-01

    Modified live virus vaccines (MLVs) are used on swine farms to control porcine reproductive and respiratory syndrome virus (PRRSV). MLVs from classical PRRSV (C-PRRSV) provide some protection against emergent highly pathogenic PRRSV (HP-PRRSV). This study characterized the protective efficacy and immune response to MLVs from C-PRRSV (CH-1R) or HP-PRRSV (HuN4-F112) in a challenge using HP-PRRSV (HuN4). The outcomes were clinical signs of disease, pathological changes in the thymus and lungs, viremia, and humoral and cellular immune responses. CH-1R provided some protection against challenge with HuN4, while HuN4-F112 was protective in the HuN4 challenge. Compared to unvaccinated piglets, the vaccinated piglets had milder symptoms and fewer pathological changes in the lung and thymus. Piglets vaccinated with HuN4-F112 had higher antibody titers and lower viral loads than piglets vaccinated with CH-1R post challenge. The differences in outcome between the MLVs suggested that underlying differences in the immune responses might warrant further study. PMID:27119981

  8. Models of highly pathogenic avian influenza epidemics in commercial poultry flocks in Nigeria and Ghana

    PubMed Central

    Pelletier, Sky T. K.; Rorres, Chris; Macko, Peter C.; Peters, Sarah

    2013-01-01

    State-scale and premises-scale gravity models for the spread of highly pathogenic avian influenza (H5N1) in Nigeria and Ghana were used to provide a basis for risk maps for future epidemics and to compare and rank plausible culling and vaccination strategies for control. Maximum likelihood methods were used to fit the models to the 2006–2007 outbreaks. The sensitivity and specificity of the state-scale model-generated probabilities that any given state would be involved in an epidemic were each 57 %. The premises-based model indicated that reactive, countrywide vaccination strategies, in which the order in which flocks are vaccinated was strictly determined by known risk factors for infection, were more effective in reducing the final size of the epidemic and the epidemic impact than vaccinating flocks at random or ring vaccination. The model suggests that an introduction of highly pathogenic avian influenza (H5N1) into Ghana had a high chance (84 %) of causing a major outbreak. That this did not happen was most probably a result of the very swift Ghanaian response to news of the first introductions. PMID:22476732

  9. Newly Emergent Highly Pathogenic H5N9 Subtype Avian Influenza A Virus

    PubMed Central

    Yu, Yang; Wang, Xingbo; Jin, Tao; Wang, Hailong; Si, Weiying; Yang, Hui; Wu, Jiusheng; Yan, Yan; Liu, Guang; Sang, Xiaoyu; Wu, Xiaopeng; Gao, Yuwei; Xia, Xianzhu; Yu, Xinfen; Pan, Jingcao; Gao, George F.

    2015-01-01

    ABSTRACT The novel H7N9 avian influenza virus (AIV) was demonstrated to cause severe human respiratory infections in China. Here, we examined poultry specimens from live bird markets linked to human H7N9 infection in Hangzhou, China. Metagenomic sequencing revealed mixed subtypes (H5, H7, H9, N1, N2, and N9). Subsequently, AIV subtypes H5N9, H7N9, and H9N2 were isolated. Evolutionary analysis showed that the hemagglutinin gene of the novel H5N9 virus originated from A/Muscovy duck/Vietnam/LBM227/2012 (H5N1), which belongs to clade 2.3.2.1. The neuraminidase gene of the novel H5N9 virus originated from human-infective A/Hangzhou/1/2013 (H7N9). The six internal genes were similar to those of other H5N1, H7N9, and H9N2 virus strains. The virus harbored the PQRERRRKR/GL motif characteristic of highly pathogenic AIVs at the HA cleavage site. Receptor-binding experiments demonstrated that the virus binds α-2,3 sialic acid but not α-2,6 sialic acid. Identically, pathogenicity experiments also showed that the virus caused low mortality rates in mice. This newly isolated H5N9 virus is a highly pathogenic reassortant virus originating from H5N1, H7N9, and H9N2 subtypes. Live bird markets represent a potential transmission risk to public health and the poultry industry. IMPORTANCE This investigation confirms that the novel H5N9 subtype avian influenza A virus is a reassortant strain originating from H5N1, H7N9, and H9N2 subtypes and is totally different from the H5N9 viruses reported before. The novel H5N9 virus acquired a highly pathogenic H5 gene and an N9 gene from human-infecting subtype H7N9 but caused low mortality rates in mice. Whether this novel H5N9 virus will cause human infections from its avian host and become a pandemic subtype is not known yet. It is therefore imperative to assess the risk of emergence of this novel reassortant virus with potential transmissibility to public health. PMID:26085150

  10. The hidden face of academic researches on classified highly pathogenic microorganisms.

    PubMed

    Devaux, Christian A

    2015-01-01

    Highly pathogenic microorganisms and toxins are manipulated in academic laboratories for fundamental research purposes, diagnostics, drugs and vaccines development. Obviously, these infectious pathogens represent a potential risk for human and/or animal health and their accidental or intentional release (biosafety and biosecurity, respectively) is a major concern of governments. In the past decade, several incidents have occurred in laboratories and reported by media causing fear and raising a sense of suspicion against biologists. Some scientists have been ordered by US government to leave their laboratory for long periods of time following the occurrence of an incident involving infectious pathogens; in other cases laboratories have been shut down and universities have been forced to pay fines and incur a long-term ban on funding after gross negligence of biosafety/biosecurity procedures. Measures of criminal sanctions have also been taken to minimize the risk that such incidents can reoccur. As United States and many other countries, France has recently strengthened its legal measures for laboratories' protection. During the past two decades, France has adopted a series of specific restriction measures to better protect scientific discoveries with a potential economic/social impact and prevent their misuse by ill-intentioned people without affecting the progress of science through fundamental research. French legal regulations concerning scientific discoveries have progressively strengthened since 2001, until the publication in November 2011 of a decree concerning the "PPST" (for "Protection du Potentiel Scientifique et Technique de la nation", the protection of sensitive scientific data). Following the same logic of protection of sensitive scientific researches, regulations were also adopted in an order published in April 2012 concerning the biology and health field. The aim was to define the legal framework that precise the conditions for authorizing

  11. High-Frequency Phenotypic Reversion and Pathogenicity of an Acyclovir-Resistant Herpes Simplex Virus Mutant

    PubMed Central

    Griffiths, Anthony; Coen, Donald M.

    2003-01-01

    A double-guanine-insertion mutation within a run of guanines in the herpes simplex virus gene encoding thymidine kinase (TK) was previously found in an acyclovir-resistant clinical isolate. This mutation was engineered into strain KOS, and stocks were generated from single plaques. Plaque autoradiography revealed that most plaques in such stocks exhibited low levels of TK activity, while ∼3% of plaques exhibited high levels of TK activity, indicating a remarkably high frequency of phenotypic reversion. This virus was able to reactivate from latency in mouse ganglia; a fraction of the reactivating virus expressed a high level of TK activity due to an additional G insertion, suggesting that the observed genetic instability contributed to pathogenicity. PMID:12525666

  12. High-mobility BaSnO{sub 3} grown by oxide molecular beam epitaxy

    SciTech Connect

    Raghavan, Santosh; Schumann, Timo; Kim, Honggyu; Zhang, Jack Y.; Cain, Tyler A.; Stemmer, Susanne

    2016-01-01

    High-mobility perovskite BaSnO{sub 3} films are of significant interest as new wide bandgap semiconductors for power electronics, transparent conductors, and as high mobility channels for epitaxial integration with functional perovskites. Despite promising results for single crystals, high-mobility BaSnO{sub 3} films have been challenging to grow. Here, we demonstrate a modified oxide molecular beam epitaxy (MBE) approach, which supplies pre-oxidized SnO{sub x}. This technique addresses issues in the MBE of ternary stannates related to volatile SnO formation and enables growth of epitaxial, stoichiometric BaSnO{sub 3}. We demonstrate room temperature electron mobilities of 150 cm{sup 2} V{sup −1} s{sup −1} in films grown on PrScO{sub 3}. The results open up a wide range of opportunities for future electronic devices.

  13. Bacterial Pathogens and Community Composition in Advanced Sewage Treatment Systems Revealed by Metagenomics Analysis Based on High-Throughput Sequencing

    PubMed Central

    Lu, Xin; Zhang, Xu-Xiang; Wang, Zhu; Huang, Kailong; Wang, Yuan; Liang, Weigang; Tan, Yunfei; Liu, Bo; Tang, Junying

    2015-01-01

    This study used 454 pyrosequencing, Illumina high-throughput sequencing and metagenomic analysis to investigate bacterial pathogens and their potential virulence in a sewage treatment plant (STP) applying both conventional and advanced treatment processes. Pyrosequencing and Illumina sequencing consistently demonstrated that Arcobacter genus occupied over 43.42% of total abundance of potential pathogens in the STP. At species level, potential pathogens Arcobacter butzleri, Aeromonas hydrophila and Klebsiella pneumonia dominated in raw sewage, which was also confirmed by quantitative real time PCR. Illumina sequencing also revealed prevalence of various types of pathogenicity islands and virulence proteins in the STP. Most of the potential pathogens and virulence factors were eliminated in the STP, and the removal efficiency mainly depended on oxidation ditch. Compared with sand filtration, magnetic resin seemed to have higher removals in most of the potential pathogens and virulence factors. However, presence of the residual A. butzleri in the final effluent still deserves more concerns. The findings indicate that sewage acts as an important source of environmental pathogens, but STPs can effectively control their spread in the environment. Joint use of the high-throughput sequencing technologies is considered a reliable method for deep and comprehensive overview of environmental bacterial virulence. PMID:25938416

  14. Use of high-throughput mass spectrometry to elucidate host-pathogen interactions in Salmonella

    SciTech Connect

    Rodland, Karin D.; Adkins, Joshua N.; Ansong, Charles; Chowdhury, Saiful M.; Manes, Nathan P.; Shi, Liang; Yoon, Hyunjin; Smith, Richard D.; Heffron, Fred

    2008-12-01

    New improvements to mass spectrometry include increased sensitivity, improvements in analyzing the collected data, and most important, from the standpoint of this review, a much higher throughput allowing analysis of many samples in a single day. This short review describes how host-pathogen interactions can be dissected by mass spectrometry using Salmonella as a model system. The approach allowed direct identification of the majority of annotate Salmonella proteins, how expression changed under various in vitro growth conditions, and how this relates to virulence and expression within host cell cells. One of the most significant findings is that a very high percentage of the all annotated genes (>20%) are regulated post-transcriptionally. In addition, new and unexpected interactions have been identified for several Salmonella virulence regulators that involve protein-protein interactions suggesting additional functions of the regulator in coordinating virulence expression. Overall high throughput mass spectrometer provides a new view of pathogen-host interaction emphasizing the protein products and defining how protein interactions determine the outcome of infection.

  15. Use of high-throughput mass spectrometry to elucidate host pathogen interactions in Salmonella

    SciTech Connect

    Rodland, Karin D.; Adkins, Joshua N.; Ansong, Charles; Chowdhury, Saiful M.; Manes, Nathan P.; Shi, Liang; Yoon, Hyunjin; Smith, Richard D.; Heffron, Fred

    2008-12-01

    Capabilities in mass spectrometry are evolving rapidly, with recent improvements in sensitivity, data analysis, and most important, from the standpoint of this review, much higher throughput allowing analysis of many samples in a single day. This short review describes how these improvements in mass spectrometry can be used to dissect host-pathogen interactions using Salmonella as a model system. This approach enabled direct identification of the majority of annotated Salmonella proteins, quantitation of expression changes under various in vitro growth conditions, and new insights into virulence and expression of Salmonella proteins within host cell cells. One of the most significant findings is that a very high percentage of the all annotated genes (>20%) in Salmonella are regulated post-transcriptionally. In addition, new and unexpected interactions have been identified for several Salmonella virulence regulators that involve protein-protein interactions, suggesting additional functions of these regulators in coordinating virulence expression. Overall high throughput mass spectrometry provides a new view of pathogen-host interactions emphasizing the protein products and defining how protein interactions determine the outcome of infection.

  16. Epidemiology and ecology of highly pathogenic avian influenza with particular emphasis on South East Asia.

    PubMed

    Martin, V; Sims, L; Lubroth, J; Pfeiffer, D; Slingenbergh, J; Domenech, J

    2006-01-01

    Highly pathogenic avian influenza (HPAI) has been recognised as a serious viral disease of poultry since 1878. The number of recorded outbreaks of HPAI has increased globally in the past 10 years culminating in 2004 with the unprecedented outbreaks of H5N1 HPAI involving at least nine countries in East and South-East Asia. Apart from the geographical extent of these outbreaks and apparent rapid spread, this epidemic has a number of unique features, among which is the role that asymptomatic domestic waterfowl and more particularly free-ranging ducks play in the transmission of highly pathogenic H5N1. Field epidemiological studies have been conducted by the Food and Agriculture Organization and several collaborative centres to explore the factors that could have led to a change from infection to the emergence of widespread disease in 2003-2004 and 2005. Domestic waterfowl, specific farming practices and agro-ecological environments have been identified to play a key role in the occurrence, maintenance and spread of HPAI. Although there are some questions that remain unanswered regarding the origins of the 2004 outbreaks, the current understanding of the ecology and epidemiology of the disease should now lead to the development of adapted targeted surveillance studies and control strategies. PMID:16447491

  17. Model-based evaluation of highly and low pathogenic avian influenza dynamics in wild birds

    USGS Publications Warehouse

    Hénaux, Viviane; Samuel, Michael D.; Bunck, Christine M.

    2010-01-01

    There is growing interest in avian influenza (AI) epidemiology to predict disease risk in wild and domestic birds, and prevent transmission to humans. However, understanding the epidemic dynamics of highly pathogenic (HPAI) viruses remains challenging because they have rarely been detected in wild birds. We used modeling to integrate available scientific information from laboratory and field studies, evaluate AI dynamics in individual hosts and waterfowl populations, and identify key areas for future research. We developed a Susceptible-Exposed-Infectious-Recovered (SEIR) model and used published laboratory challenge studies to estimate epidemiological parameters (rate of infection, latency period, recovery and mortality rates), considering the importance of age classes, and virus pathogenicity. Infectious contact leads to infection and virus shedding within 1–2 days, followed by relatively slower period for recovery or mortality. We found a shorter infectious period for HPAI than low pathogenic (LP) AI, which may explain that HPAI has been much harder to detect than LPAI during surveillance programs. Our model predicted a rapid LPAI epidemic curve, with a median duration of infection of 50–60 days and no fatalities. In contrast, HPAI dynamics had lower prevalence and higher mortality, especially in young birds. Based on field data from LPAI studies, our model suggests to increase surveillance for HPAI in post-breeding areas, because the presence of immunologically naïve young birds is predicted to cause higher HPAI prevalence and bird losses during this season. Our results indicate a better understanding of the transmission, infection, and immunity-related processes is required to refine predictions of AI risk and spread, improve surveillance for HPAI in wild birds, and develop disease control strategies to reduce potential transmission to domestic birds and/or humans.

  18. A highly sensitive and flexible magnetic nanoprobe labeled immunochromatographic assay platform for pathogen Vibrio parahaemolyticus.

    PubMed

    Liu, Yingying; Zhang, Zhaohuan; Wang, Yilong; Zhao, Yong; Lu, Ying; Xu, Xiaowei; Yan, Jun; Pan, Yingjie

    2015-10-15

    A magnetic nanoprobe labeled immunochromatographic test strip (MNP/ICTS) was developed to detect food-borne pathogen Vibrio parahaemolyticus. Specific antibody against V. parahaemolyticus was used as test line by coating onto the nitrocellulose membrane. Magnetic nanoprobe was prepared by immobilizing the specific antibody onto the surface of superparamagnetic nanoparticles. Specificity and sensitivity of the MNP/ICTS system were verified by artificially contaminated shrimp homogenate samples. Reliability and application feasibility of the MNP/ICTS system were demonstrated by using seafood samples (n=36). Comparing with polymerase chain reaction (PCR) and traditional culture methods, the MNP/ICTS system is found to be not only a rapid qualitative analysis (~10 min), but also an accurately quantitative detection platform. Through its rapid magnetic separation property, the MNP/ICTS system is capable to flexibly combine with a sample enrichment and pre-incubation process. This combination makes the qualitative sensitivity for the food samples surged more than 100-fold. A naked-eye observation of 1.58×10(2) CFU/g V. parahaemolyticus was realized. This sensitivity could meet the V. parahaemolyticus test threshold value in many countries. Also, the total sample pre-treatment plus MNP/ICTS assay only needs about 4.5h. Namely, we can get test results in a day. Hence, the developed MNP/ICTS assay platform is simple, rapid and highly sensitive. It is a flexible test platform for pathogen detection. The favorable comparison with PCR and culture methods further proves that the developed MNP/ICTS is applicable into food-borne pathogen or other areas where a simple, rapid, sensitive and point-of-care analysis is desirable. PMID:26188497

  19. High Rate of Mobilization for blaCTX-Ms

    PubMed Central

    Reik, Rebecca A.; Jacobs, Stephen D.; Medina, Mónica; Meyer, Matthew P.; McGowan, John E.; Tenover, Fred C.

    2008-01-01

    We constructed a phylogenetic analysis of class A β-lactamases and found that the blaCTX-Ms have been mobilized to plasmids ≈10 times more frequently than other class A β-lactamases. We also found that the blaCTX-Ms are descended from a common ancestor that was incorporated in ancient times into the chromosome of the ancestor of Kluyvera species through horizontal transfer. Considerable sequence divergence has occurred among the descendents of that ancestral gene sequence since that gene was inserted. That divergence has mainly occurred in the presence of purifying selection, which indicates a slow rate of evolution for blaCTX-Ms in the pre–antimicrobial drug era. PMID:18325257

  20. High flow, low mobile weight quick disconnect system

    NASA Technical Reports Server (NTRS)

    Smith, Ronn G. (Inventor); Nagy, Jr., Zoltan Frank (Inventor); Moszczienski, Joseph Roch (Inventor)

    2010-01-01

    A fluid coupling device and coupling system that may start and stop the flow of a fluid is disclosed. In some embodiments, first and second couplings are provided having an actuator coupled with each of the couplings. The couplings and actuators may be detachable to provide quick disconnect features and, in some embodiments, provide unitary actuation for the actuators of the coupling device to facilitate connection in mobile applications. Actuation may occur as the two couplings and actuators are engaged and disengaged and may occur by rotational actuation of the actuators. Rotational actuation can be provided to ensure flow through the coupling device, which in some embodiments may further provide an offset venturi feature. Upon disengagement, a compression element such as a compression spring can be provided to return the actuators to a closed position. Some embodiments further provide a seal external to the actuators and provided at incipient engagement of the couplings.

  1. Highly mobile laser ranging facilities of the Crustal Dynamics Project

    NASA Technical Reports Server (NTRS)

    Coates, R. J.

    1984-01-01

    Technical specifications, performance, and applications of the NASA transportable laser ranging systems (TLRS-1 and -2) for use in the Crustal Dynamics Program are described. TLRS-1 is truck-mounted, with the laser deployed through the roof. Interacting with the LAGEOS satellite, TLRS has a photoelectric receiver for gathering data on the roundtrip time of the laser beam for calculations of the range gate. The laser has a 0.1 nsec pulse at 3.5 mJ/pulse. Range is measured to within an error of 9 cm. The TLRS-2 version is configured for ease of air transport and modular breakdown and assembly. It has been activated on Easter Island. TLRS-3 and -4 are in development to serve as mobile units in South America and the Mediterranean area.

  2. New approach to delist highly pathogenic avian influenza viruses from BSL3+ select agents to BSL2 non-select status for diagnostics and vaccines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Highly pathogenic avian influenza viruses (AIV) are Select Agents in the United States and are required to be handled in bio-containment level 3 enhanced (BSL3+) facilities. Using a reverse genetics system, we attenuated a highly pathogenic virus with the goal of making it low pathogenic and having...

  3. High Electron Mobility Transistor Structures on Sapphire Substrates Using CMOS Compatible Processing Techniques

    NASA Technical Reports Server (NTRS)

    Mueller, Carl; Alterovitz, Samuel; Croke, Edward; Ponchak, George

    2004-01-01

    System-on-a-chip (SOC) processes are under intense development for high-speed, high frequency transceiver circuitry. As frequencies, data rates, and circuit complexity increases, the need for substrates that enable high-speed analog operation, low-power digital circuitry, and excellent isolation between devices becomes increasingly critical. SiGe/Si modulation doped field effect transistors (MODFETs) with high carrier mobilities are currently under development to meet the active RF device needs. However, as the substrate normally used is Si, the low-to-modest substrate resistivity causes large losses in the passive elements required for a complete high frequency circuit. These losses are projected to become increasingly troublesome as device frequencies progress to the Ku-band (12 - 18 GHz) and beyond. Sapphire is an excellent substrate for high frequency SOC designs because it supports excellent both active and passive RF device performance, as well as low-power digital operations. We are developing high electron mobility SiGe/Si transistor structures on r-plane sapphire, using either in-situ grown n-MODFET structures or ion-implanted high electron mobility transistor (HEMT) structures. Advantages of the MODFET structures include high electron mobilities at all temperatures (relative to ion-implanted HEMT structures), with mobility continuously improving to cryogenic temperatures. We have measured electron mobilities over 1,200 and 13,000 sq cm/V-sec at room temperature and 0.25 K, respectively in MODFET structures. The electron carrier densities were 1.6 and 1.33 x 10(exp 12)/sq cm at room and liquid helium temperature, respectively, denoting excellent carrier confinement. Using this technique, we have observed electron mobilities as high as 900 sq cm/V-sec at room temperature at a carrier density of 1.3 x 10(exp 12)/sq cm. The temperature dependence of mobility for both the MODFET and HEMT structures provides insights into the mechanisms that allow for enhanced

  4. Genetic variation, pathogenicity, and immunogenicity of highly pathogenic porcine reproductive and respiratory syndrome virus strain XH-GD at different passage levels.

    PubMed

    Chen, Yao; He, Shuyi; Sun, Long; Luo, Yongfeng; Sun, Yankuo; Xie, Jiexiong; Zhou, Pei; Su, Shuo; Zhang, Guihong

    2016-01-01

    Porcine reproductive and respiratory syndrome (PRRS) is one of the most economically important infectious diseases of swine worldwide. Immunization with an attenuated vaccine is considered an effective method for reducing the economic losses resulting from porcine reproductive and respiratory syndrome virus (PRRSV) infection. Several studies have shown that PRRSV can be attenuated by passage in Marc-145 cells, but it is still not clear whether this attenuation influences the immunogenicity of PRRSV and what the mechanism of attenuation is. In order to study the mechanism of attenuation and immunogenicity of highly pathogenic (HP) PRRSV, the HP-PRRSV strain XH-GD was serially 122 times passaged in Marc-145 cells. Genomic sequence comparisons were made at selected passages. To explore the differences in pathogenicity and immunogenicity at different passages, three passages (P5, P62 and P122) were selected for an animal challenge experiment, which showed that passage in Marc-145 cells resulted in attenuation of the virus. After 122 passages, 35 amino acid changes were observed in the structural proteins and non-structural proteins. The animal challenge experiment showed that pathogenicity decreased with increasing passage number. The N antibody level and specific neutralizing (SN) antibody titers also decreased with increasing passage number in the late stage of the animal experiment. This study indicated that the virulence of XH-GD was decreased by passage in Marc-145 cells and that overattenuation might influence the immunogenicity of virus. These results might contribute to our understanding of the mechanism of attenuation. PMID:26483282

  5. Pathogenicity of Genetically Similar, H5N1 Highly Pathogenic Avian Influenza Virus Strains in Chicken and the Differences in Sensitivity among Different Chicken Breeds

    PubMed Central

    Matsuu, Aya; Kobayashi, Tomoko; Patchimasiri, Tuangthong; Shiina, Takashi; Suzuki, Shingo; Chaichoune, Kridsada; Ratanakorn, Parntep; Hiromoto, Yasuaki; Abe, Haruka; Parchariyanon, Sujira; Saito, Takehiko

    2016-01-01

    Differences in the pathogenicity of genetically closely related H5N1 highly pathogenic avian influenza viruses (HPAIVs) were evaluated in White Leghorn chickens. These viruses varied in the clinical symptoms they induced, including lethality, virus shedding, and replication in host tissues. A comparison of the host responses in the lung, brain, and spleen suggested that the differences in viral replication efficiency were related to the host cytokine response at the early phase of infection, especially variations in the proinflammatory cytokine IL-6. Based on these findings, we inoculated the virus that showed the mildest pathogenicity among the five tested, A/pigeon/Thailand/VSMU-7-NPT/2004, into four breeds of Thai indigenous chicken, Phadu-Hung-Dang (PHD), Chee, Dang, and Luang-Hung-Khao (LHK), to explore effects of genetic background on host response. Among these breeds, Chee, Dang, and LHK showed significantly longer survival times than White Leghorns. Virus shedding from dead Thai indigenous chickens was significantly lower than that from White Leghorns. Although polymorphisms were observed in the Mx and MHC class I genes, there was no significant association between the polymorphisms in these loci and resistance to HPAIV. PMID:27078641

  6. Identifying Pathogenicity Islands in Bacterial Pathogenomics Using Computational Approaches

    PubMed Central

    Che, Dongsheng; Hasan, Mohammad Shabbir; Chen, Bernard

    2014-01-01

    High-throughput sequencing technologies have made it possible to study bacteria through analyzing their genome sequences. For instance, comparative genome sequence analyses can reveal the phenomenon such as gene loss, gene gain, or gene exchange in a genome. By analyzing pathogenic bacterial genomes, we can discover that pathogenic genomic regions in many pathogenic bacteria are horizontally transferred from other bacteria, and these regions are also known as pathogenicity islands (PAIs). PAIs have some detectable properties, such as having different genomic signatures than the rest of the host genomes, and containing mobility genes so that they can be integrated into the host genome. In this review, we will discuss various pathogenicity island-associated features and current computational approaches for the identification of PAIs. Existing pathogenicity island databases and related computational resources will also be discussed, so that researchers may find it to be useful for the studies of bacterial evolution and pathogenicity mechanisms. PMID:25437607

  7. Systemic virus distribution and host responses in brain and intestine of chickens infected with low pathogenic or high pathogenic avian influenza virus

    PubMed Central

    2012-01-01

    Background Avian influenza virus (AIV) is classified into two pathotypes, low pathogenic (LP) and high pathogenic (HP), based on virulence in chickens. Differences in pathogenicity between HPAIV and LPAIV might eventually be related to specific characteristics of strains, tissue tropism and host responses. Methods To study differences in disease development between HPAIV and LPAIV, we examined the first appearance and eventual load of viral RNA in multiple organs as well as host responses in brain and intestine of chickens infected with two closely related H7N1 HPAIV or LPAIV strains. Results Both H7N1 HPAIV and LPAIV spread systemically in chickens after a combined intranasal/intratracheal inoculation. In brain, large differences in viral RNA load and host gene expression were found between H7N1 HPAIV and LPAIV infected chickens. Chicken embryo brain cell culture studies revealed that both HPAIV and LPAIV could infect cultivated embryonic brain cells, but in accordance with the absence of the necessary proteases, replication of LPAIV was limited. Furthermore, TUNEL assay indicated apoptosis in brain of HPAIV infected chickens only. In intestine, where endoproteases that cleave HA of LPAIV are available, we found minimal differences in the amount of viral RNA and a large overlap in the transcriptional responses between HPAIV and LPAIV infected chickens. Interestingly, brain and ileum differed clearly in the cellular pathways that were regulated upon an AI infection. Conclusions Although both H7N1 HPAIV and LPAIV RNA was detected in a broad range of tissues beyond the respiratory and gastrointestinal tract, our observations indicate that differences in pathogenicity and mortality between HPAIV and LPAIV could originate from differences in virus replication and the resulting host responses in vital organs like the brain. PMID:22390870

  8. Modelling the wind-borne spread of highly pathogenic avian influenza virus between farms.

    PubMed

    Ssematimba, Amos; Hagenaars, Thomas J; de Jong, Mart C M

    2012-01-01

    A quantitative understanding of the spread of contaminated farm dust between locations is a prerequisite for obtaining much-needed insight into one of the possible mechanisms of disease spread between farms. Here, we develop a model to calculate the quantity of contaminated farm-dust particles deposited at various locations downwind of a source farm and apply the model to assess the possible contribution of the wind-borne route to the transmission of Highly Pathogenic Avian Influenza virus (HPAI) during the 2003 epidemic in the Netherlands. The model is obtained from a Gaussian Plume Model by incorporating the dust deposition process, pathogen decay, and a model for the infection process on exposed farms. Using poultry- and avian influenza-specific parameter values we calculate the distance-dependent probability of between-farm transmission by this route. A comparison between the transmission risk pattern predicted by the model and the pattern observed during the 2003 epidemic reveals that the wind-borne route alone is insufficient to explain the observations although it could contribute substantially to the spread over short distance ranges, for example, explaining 24% of the transmission over distances up to 25 km. PMID:22348042

  9. Rapid anti-pathogen response in ant societies relies on high genetic diversity.

    PubMed

    Ugelvig, Line V; Kronauer, Daniel J C; Schrempf, Alexandra; Heinze, Jürgen; Cremer, Sylvia

    2010-09-22

    Social organisms are constantly exposed to infectious agents via physical contact with conspecifics. While previous work has shown that disease susceptibility at the individual and group level is influenced by genetic diversity within and between group members, it remains poorly understood how group-level resistance to pathogens relates directly to individual physiology, defence behaviour and social interactions. We investigated the effects of high versus low genetic diversity on both the individual and collective disease defences in the ant Cardiocondyla obscurior. We compared the antiseptic behaviours (grooming and hygienic behaviour) of workers from genetically homogeneous and diverse colonies after exposure of their brood to the entomopathogenic fungus Metarhizium anisopliae. While workers from diverse colonies performed intensive allogrooming and quickly removed larvae covered with live fungal spores from the nest, workers from homogeneous colonies only removed sick larvae late after infection. This difference was not caused by a reduced repertoire of antiseptic behaviours or a generally decreased brood care activity in ants from homogeneous colonies. Our data instead suggest that reduced genetic diversity compromises the ability of Cardiocondyla colonies to quickly detect or react to the presence of pathogenic fungal spores before an infection is established, thereby affecting the dynamics of social immunity in the colony. PMID:20444720

  10. High-throughput screening of tick-borne pathogens in Europe

    PubMed Central

    Michelet, Lorraine; Delannoy, Sabine; Devillers, Elodie; Umhang, Gérald; Aspan, Anna; Juremalm, Mikael; Chirico, Jan; van der Wal, Fimme J.; Sprong, Hein; Boye Pihl, Thomas P.; Klitgaard, Kirstine; Bødker, Rene; Fach, Patrick; Moutailler, Sara

    2014-01-01

    Due to increased travel, climatic, and environmental changes, the incidence of tick-borne disease in both humans and animals is increasing throughout Europe. Therefore, extended surveillance tools are desirable. To accurately screen tick-borne pathogens (TBPs), a large scale epidemiological study was conducted on 7050 Ixodes ricinus nymphs collected from France, Denmark, and the Netherlands using a powerful new high-throughput approach. This advanced methodology permitted the simultaneous detection of 25 bacterial, and 12 parasitic species (including; Borrelia, Anaplasma, Ehrlichia, Rickettsia, Bartonella, Candidatus Neoehrlichia, Coxiella, Francisella, Babesia, and Theileria genus) across 94 samples. We successfully determined the prevalence of expected (Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, Rickettsia helvetica, Candidatus Neoehrlichia mikurensis, Babesia divergens, Babesia venatorum), unexpected (Borrelia miyamotoi), and rare (Bartonella henselae) pathogens in the three European countries. Moreover we detected Borrelia spielmanii, Borrelia miyamotoi, Babesia divergens, and Babesia venatorum for the first time in Danish ticks. This surveillance method represents a major improvement in epidemiological studies, able to facilitate comprehensive testing of TBPs, and which can also be customized to monitor emerging diseases. PMID:25120960

  11. Rapid anti-pathogen response in ant societies relies on high genetic diversity

    PubMed Central

    Ugelvig, Line V.; Kronauer, Daniel J. C.; Schrempf, Alexandra; Heinze, Jürgen; Cremer, Sylvia

    2010-01-01

    Social organisms are constantly exposed to infectious agents via physical contact with conspecifics. While previous work has shown that disease susceptibility at the individual and group level is influenced by genetic diversity within and between group members, it remains poorly understood how group-level resistance to pathogens relates directly to individual physiology, defence behaviour and social interactions. We investigated the effects of high versus low genetic diversity on both the individual and collective disease defences in the ant Cardiocondyla obscurior. We compared the antiseptic behaviours (grooming and hygienic behaviour) of workers from genetically homogeneous and diverse colonies after exposure of their brood to the entomopathogenic fungus Metarhizium anisopliae. While workers from diverse colonies performed intensive allogrooming and quickly removed larvae covered with live fungal spores from the nest, workers from homogeneous colonies only removed sick larvae late after infection. This difference was not caused by a reduced repertoire of antiseptic behaviours or a generally decreased brood care activity in ants from homogeneous colonies. Our data instead suggest that reduced genetic diversity compromises the ability of Cardiocondyla colonies to quickly detect or react to the presence of pathogenic fungal spores before an infection is established, thereby affecting the dynamics of social immunity in the colony. PMID:20444720

  12. Identity Efficiency for High-Performance Ambient Pressure Ion Mobility Spectrometry.

    PubMed

    Kanu, A Bakarr; Leal, Anne

    2016-03-15

    A new approach to reduce the false-positive responses commonly encountered in the field when drugs and explosives are detected is reported for an electrospray ionization high-performance ion mobility spectrometry (ESI-HPIMS). In this article, we report on the combination of reduced mobility and the width-at-half-height of a peak to give a new parameter called conditional reduced mobility (CRM). It was found that the CRM was capable of differentiating between real drugs peaks from that of a false-positive peak and may help to reduce false-positive rates. This effect was demonstrated using 11 drugs (amphetamine, cannabidiol, cocaine, codeine, heroine, methamphetamine, morphine, phentermine, L-phenylepherine, proglitazone, and rosiglitazone) and seven interferences chosen from off-the-shelf products. This report determined and compared CRM, resolving power (R(m)), and diffusion-limited conditional theoretical reduced mobility (DLCTRM) for ESI-HPIMS. The most important parameters for determining CRM are reduced mobility and width-at-half-height of a peak. There is a specific optimum voltage, gate pulse width, resolving power, and now CRM for each ion. DLCTRM indicate the optimum reduced mobility that is not normally possible under field conditions. CRM predicts the condition at which a target compound can be differentiated from a false-positive response. This was possible because different ions exhibits different drifting patterns and hence a different peak broadening phenomenon inside an ion mobility tube. Reduced mobility for target compounds reported were reproducible to within 2% for ESI-HPIMS. The estimated resolving power for the ESI-HPIMS used in this study was 61 ± 0.22. Conditional reduced mobility introduced in this paper show differences between target compounds and false-positive peaks as high as 74%, as was the case for cannabidiol and interference #1 at 70 μs gate pulse width. PMID:26919030

  13. Analysis of Clinical Isolates of Helicobacter pylori in Pakistan Reveals High Degrees of Pathogenicity and High Frequencies of Antibiotic Resistance

    PubMed Central

    Rasheed, Faisal; Campbell, Barry James; Alfizah, Hanafiah; Varro, Andrea; Zahra, Rabaab; Yamaoka, Yoshio; Pritchard, David Mark

    2014-01-01

    Background Antibiotic resistance in Helicobacter pylori contributes to failure in eradicating the infection and is most often due to point and missense mutations in a few key genes. Methods The antibiotic susceptibility profiles of H. pylori isolates from 46 Pakistani patients were determined by Etest. Resistance and pathogenicity genes were amplified, and sequences were analyzed to determine the presence of mutations. Results A high percentage of isolates (73.9%) were resistant to metronidazole (MTZ), with considerable resistance to clarithromycin (CLR; 47.8%) and amoxicillin (AML; 54.3%) also observed. Relatively few isolates were resistant to tetracycline (TET; 4.3%) or to ciprofloxacin (CIP; 13%). However, most isolates (n = 43) exhibited resistance to one or more antibiotics. MTZ-resistant isolates contained missense mutations in oxygen-independent NADPH nitroreductase (RdxA; 8 mutations found) and NADH flavin oxidoreductase (FrxA; 4 mutations found). In the 23S rRNA gene, responsible for CLR resistance, a new point mutation (A2181G) and 4 previously reported mutations were identified. Pathogenicity genes cagA, dupA, and vacA s1a/m1 were detected frequently in isolates which were also found to be resistant to MTZ, CLR, and AML. A high percentage of CagA and VacA seropositivity was also observed in these patients. Phylogenetic analysis of partial sequences showed uniform distribution of the 3′ region of cagA throughout the tree. Conclusions We have identified H. pylori isolates in Pakistan which harbor pathogenicity genes and worrying antibiotic resistance profiles as a result of having acquired multiple point and missense mutations. H. pylori eradication regimens should therefore be reevaluated in this setting. PMID:24827414

  14. Avian influenza virus hemagglutinins H2, H4, H8, and H14 support a highly pathogenic phenotype

    PubMed Central

    Veits, Jutta; Weber, Siegfried; Stech, Olga; Breithaupt, Angele; Gräber, Marcus; Gohrbandt, Sandra; Bogs, Jessica; Hundt, Jana; Teifke, Jens P.; Mettenleiter, Thomas C.; Stech, Jürgen

    2012-01-01

    High-pathogenic avian influenza viruses (HPAIVs) evolve from low-pathogenic precursors specifying the HA serotypes H5 or H7 by acquisition of a polybasic HA cleavage site. As the reason for this serotype restriction has remained unclear, we aimed to distinguish between compatibility of a polybasic cleavage site with H5/H7 HA only and unique predisposition of these two serotypes for insertion mutations. To this end, we introduced a polybasic cleavage site into the HA of several low-pathogenic avian strains with serotypes H1, H2, H3, H4, H6, H8, H10, H11, H14, or H15, and rescued HA reassortants after cotransfection with the genes from either a low-pathogenic H9N2 or high-pathogenic H5N1 strain. Oculonasal inoculation with those reassortants resulted in varying pathogenicity in chicken. Recombinants containing the engineered H2, H4, H8, or H14 in the HPAIV background were lethal and exhibited i.v. pathogenicity indices of 2.79, 2.37, 2.85, and 2.61, respectively, equivalent to naturally occurring H5 or H7 HPAIV. Moreover, the H2, H4, and H8 reassortants were transmitted to some contact chickens. The H2 reassortant gained two mutations in the M2 proton channel gate region, which is affected in some HPAIVs of various origins. Taken together, in the presence of a polybasic HA cleavage site, non-H5/H7 HA can support a highly pathogenic phenotype in the appropriate viral background, indicating requirement for further adaptation. Therefore, the restriction of natural HPAIV to serotypes H5 and H7 is likely a result of their unique predisposition for acquisition of a polybasic HA cleavage site. PMID:22308331

  15. Airborne Transmission of Highly Pathogenic H7N1 Influenza Virus in Ferrets

    PubMed Central

    Finch, Courtney; Shao, Hongxia; Angel, Matthew; Chen, Hongjun; Capua, Ilaria; Cattoli, Giovanni; Monne, Isabella

    2014-01-01

    ABSTRACT Avian H7 influenza viruses are recognized as potential pandemic viruses, as personnel often become infected during poultry outbreaks. H7 infections in humans typically cause mild conjunctivitis; however, the H7N9 outbreak in the spring of 2013 has resulted in severe respiratory disease. To date, no H7 viruses have acquired the ability for sustained transmission among humans. Airborne transmission is considered a requirement for the emergence of pandemic influenza, and advanced knowledge of the molecular changes or signature required for transmission would allow early identification of pandemic vaccine seed stocks, screening and stockpiling of antiviral compounds, and eradication efforts focused on flocks harboring threatening viruses. Thus, we sought to determine if a highly pathogenic influenza A H7N1 (A/H7N1) virus with no history of human infection could become capable of airborne transmission among ferrets. We show that after 10 serial passages, A/H7N1 developed the ability to be transmitted to cohoused and airborne contact ferrets. Four amino acid mutations (PB2 T81I, NP V284M, and M1 R95K and Q211K) in the internal genes and a minimal amino acid mutation (K/R313R) in the stalk region of the hemagglutinin protein were associated with airborne transmission. Furthermore, transmission was not associated with loss of virulence. These findings highlight the importance of the internal genes in host adaptation and suggest that natural isolates carrying these mutations be further evaluated. Our results demonstrate that a highly pathogenic avian H7 virus can become capable of airborne transmission in a mammalian host, and they support ongoing surveillance and pandemic H7 vaccine development. IMPORTANCE The major findings of this report are that a highly pathogenic strain of H7N1 avian influenza virus can be adapted to become capable of airborne transmission in mammals without mutations altering receptor specificity. Changes in receptor specificity have been

  16. Transposon-based high sequence diversity in Avr-Pita alleles increases the potential for pathogenicity of Magnaporthe oryzae populations.

    PubMed

    Singh, P K; Thakur, S; Rathour, R; Variar, M; Prashanthi, S K; Singh, A K; Singh, U D; Sharma, V; Singh, N K; Sharma, T R

    2014-06-01

    Magnaporthe oryzae causes rice blast that is one of the most devastating diseases of rice worldwide. Highly variable nature of this fungus has evolved itself against major resistance genes in newly released rice varieties. Understanding the population structure of this fungus is essential for proper utilization of the rice blast resistance genes in rice crop plants. In the present study, we analyzed 133 isolates of M. oryzae from ten countries to find the allelic variation of Avr-Pita gene that is triggering Pita-mediated resistance in rice plant. The diversity analysis of these alleles showed higher level of nucleotide variation in the coding regions than the noncoding regions. Evolutionary analysis of these alleles indicates that Avr-Pita gene is under purifying selection to favor its major alleles in 133 isolates analyzed in this study. We hypothesize that the selection of favorable Avr-Pita allele in these isolates may occur through a genetic mechanism known as recurrent selective sweeps. A total of 22 functional Avr-Pita protein variants were identified in this study. Insertion of Pot3 transposable element into the promoter of Avr-Pita gene was identified in virulent isolates and was suggested that mobility of repeat elements in avirulence genes of M. oryzae seems to help in emergence of new virulent types of the pathogen. Allele-specific markers developed in this study will be helpful to identify a particular type of Avr-Pita allele from M. oryzae population which can form the basis for the deployment of Pita gene in different epidemiological regions. PMID:24633351

  17. Controlling highly pathogenic avian influenza outbreaks: An epidemiological and economic model analysis.

    PubMed

    Backer, J A; van Roermund, H J W; Fischer, E A J; van Asseldonk, M A P M; Bergevoet, R H M

    2015-09-01

    Outbreaks of highly pathogenic avian influenza (HPAI) can cause large losses for the poultry sector and for animal disease controlling authorities, as well as risks for animal and human welfare. In the current simulation approach epidemiological and economic models are combined to compare different strategies to control highly pathogenic avian influenza in Dutch poultry flocks. Evaluated control strategies are the minimum EU strategy (i.e., culling of infected flocks, transport regulations, tracing and screening of contact flocks, establishment of protection and surveillance zones), and additional control strategies comprising pre-emptive culling of all susceptible poultry flocks in an area around infected flocks (1 km, 3 km and 10 km) and emergency vaccination of all flocks except broilers around infected flocks (3 km). Simulation results indicate that the EU strategy is not sufficient to eradicate an epidemic in high density poultry areas. From an epidemiological point of view, this strategy is the least effective, while pre-emptive culling in 10 km radius is the most effective of the studied strategies. But these two strategies incur the highest costs due to long duration (EU strategy) and large-scale culling (pre-emptive culling in 10 km radius). Other analysed pre-emptive culling strategies (i.e., in 1 km and 3 km radius) are more effective than the analysed emergency vaccination strategy (in 3 km radius) in terms of duration and size of the epidemics, despite the assumed optimistic vaccination capacity of 20 farms per day. However, the total costs of these strategies differ only marginally. Extending the capacity for culling substantially reduces the duration, size and costs of the epidemic. This study demonstrates the strength of combining epidemiological and economic model analysis to gain insight in a range of consequences and thus to serve as a decision support tool in the control of HPAI epidemics. PMID:26087887

  18. Immune responses of locusts to challenge with the pathogenic fungus Metarhizium or high doses of laminarin.

    PubMed

    Mullen, Lisa M; Goldsworthy, Graham J

    2006-04-01

    Two isolates of Metarhizium anisopliae var acridum were tested for their effects on the locust immune system and for comparison with the effects of challenge by injection with laminarin. Isolate IMI 330189 (referred to hereafter as Met 189) is highly pathogenic whether applied topically as conidia or injected as blastospores. However, isolate ARSEF 728 (referred to hereafter as Met 728) is pathogenic only when injected as blastospores, suggesting that the lack of pathogenicity of topically applied conidia from this isolate is due to a failure to penetrate the insect cuticle and gain access to the haemocoel. After topical application of conidia from Met 189, no activation of prophenoloxidase is detected, but injection of blastospores from Met 189 brings about a transient increase in phenoloxidase activity in the haemolymph in both adult locusts and 5th instar nymphs, although this does not prevent fungal-induced mortality. Co-injection of adipokinetic hormone-I (AKH-I) with blastospores prolongs the activation of prophenoloxidase in the haemolymph of adult locusts, and enhances it in nymphs. It is argued that the lack of activation of prophenoloxidase in nymphs shown previously (Mullen, L., Goldsworthy, G., 2003. Changes in lipophorins are related to the activation of phenoloxidase in the haemolymph of Locusta migratoria in response to injection of immunogens. Insect Biochemistry and Molecular Biology 33, 661-670), reflects differences in the sensitivity of the immune system between adults and nymphs rather than distinct qualitative differences, and this is confirmed in this study by the demonstration that doses of laminarin higher than those used previously (>or=100 microg) do activate the prophenoloxidase cascade in 5th instar nymphs. Nodules are formed in locusts of all ages in response to fungal infection or injection of laminarin, although there is wide variation in the number, size and distribution of nodules formed. During the examination of 5th instar nymphs

  19. Fluorescent Protein Nanowire-Mediated Protein Microarrays for Multiplexed and Highly Sensitive Pathogen Detection.

    PubMed

    Men, Dong; Zhou, Juan; Li, Wei; Leng, Yan; Chen, Xinwen; Tao, Shengce; Zhang, Xian-En

    2016-07-13

    Protein microarrays are powerful tools for high-throughput and simultaneous detection of different target molecules in complex biological samples. However, the sensitivity of conventional fluorescence-labeling protein detection methods is limited by the availability of signal molecules for binding to the target molecule. Here, we built a multifunctional fluorescent protein nanowire (FNw) by harnessing self-assembly of yeast amyloid protein. The FNw integrated a large number of fluorescent molecules, thereby enhancing the fluorescent signal output in target detection. The FNw was then combined with protein microarray technology to detect proteins derived from two pathogens, including influenza virus (hemagglutinin 1, HA1) and human immunodeficiency virus (p24 and gp120). The resulting detection sensitivity achieved a 100-fold improvement over a commercially available detection reagent. PMID:27315221

  20. Poultry raising systems and highly pathogenic avian influenza outbreaks in Thailand: the situation, associations, and impacts.

    PubMed

    Chantong, Wasan; Kaneene, John B

    2011-05-01

    Highly pathogenic avian influenza (HPAI), caused by the virus strain H5N1, currently occurs worldwide with the greatest burden in Southeast Asia where the disease was first reported. In Thailand where the disease was first confirmed in January 2004, the virus had been persistent as a major threat to the poultry industry and human health over the past several years. It was generally hypothesized that the main reason for the disease to circulate in Thailand was the existence of traditional backyard chickens and free-range ducks raising systems. Consequently, this study reviewed the structure of poultry raising systems, the recent outbreaks of HPAI H5N1, the disease association to the backyard and free-grazing poultry production, and consequences of the outbreaks in Thailand. Although the major outbreaks in the country had declined, the sustaining disease surveillance and prevention are still strongly recommended. PMID:21706938

  1. Broadscale resolving power performance of a high precision uniform field ion mobility-mass spectrometer.

    PubMed

    May, Jody C; Dodds, James N; Kurulugama, Ruwan T; Stafford, George C; Fjeldsted, John C; McLean, John A

    2015-10-21

    An extensive study of two current ion mobility resolving power theories ("conditional" and "semi-empirical") was undertaken using a recently developed drift tube ion mobility-mass spectrometer. The current study investigates the quantitative agreement between experiment and theory at reduced pressure (4 Torr) for a wide range of initial ion gate widths (100 to 500 μs), and ion mobility values (K0 from 0.50 to 3.0 cm(2) V(-1) s(-1)) representing measurements obtained in helium, nitrogen, and carbon dioxide drift gas. Results suggest that the conditional resolving power theory deviates from experimental results for low mobility ions (e.g., high mass analytes) and for initial ion gate widths beyond 200 μs. A semi-empirical resolving power theory provided close-correlation of predicted resolving powers to experimental results across the full range of mobilities and gate widths investigated. Interpreting the results from the semi-empirical theory, the performance of the current instrumentation was found to be highly linear for a wide range of analytes, with optimal resolving powers being accessible for a narrow range of drift fields between 14 and 17 V cm(-1). While developed using singly-charged ion mobility data, preliminary results suggest that the semi-empirical theory has broader applicability to higher-charge state systems. PMID:26191544

  2. High mobility of landslides on the Mercury crater rims

    NASA Astrophysics Data System (ADS)

    Fukuoka, H.; Kadota, N.; Kiritoshi, I.; Sugiyama, H.; Uragami, H.

    2013-12-01

    The NASA's MESSENGER mercury spacecraft was launched by NASA in 2004, and orbital insertion was successfully completed in 2011. Among its scientific instruments, the Mercury Dual Imaging System (MDIS) and the Mercury Laser Altimeter (MLA) are used to extract the mercury terrain topography. This mission revealed various features of the mercury topography with horizontal resolution of 1 km. Up to July 2013, elevation of the north hemisphere terrain had been released on the net (Quickmap: http://messenger-act.actgate.com/msgr_public_released/react_quickmap.html). As reported by previous studies on landslides found on the lunar crater rims (Fukuoka et al., 2011), they showed extremely small H/V = tan (apparent friction) of the movement, even though almost no groundwater could have been expected ever. Authors examined the crater rims in the northern hemisphere of latitude higher than 65 degrees, because the precision of the altitude is higher in the polar and equatorial regions. We found as many similar landslides along the crater rims. Then, in order to compare the mobility of landslides with lunar ones, we have examined the apparent friction (H/T). In most cases, the H/T values of those landslides are between 0.1 and 0.2, like long-runout landslides on the Moon, Mars and Earth. If the rocks on the mercury show the similar friction as rocks on the earth, those values should be higher than 0.5. Possible mechanism of the small H/L could be cumulated shear displacement induced by repeated quakes by meteor impact over billions of years and / or exotic mechanism including tectonic function.

  3. High resolution ion mobility measurements of peptides, proteins, and atomic clusters

    NASA Astrophysics Data System (ADS)

    Hudgins, Robert Ransone

    1999-12-01

    A novel high resolution ion mobility apparatus has been constructed and applied to the study of atomic clusters and biological molecules in the gas phase. The resolving power of the high resolution apparatus is over an order of magnitude higher than has been achieved using conventional injected-ion drift tube techniques. A number of advantages of the experimental configuration, in addition to the higher resolution, are described. High resolution ion mobility measurements have been performed on atomic clusters of various composition. Several isomers for carbon cluster anions have been resolved for the first time. By comparison to computationally derived structures, detailed structural information can be extracted from the measurements. For small carbon cluster anions, ``tadpole'' isomers, where a short carbon chain is attached to a carbon ring, have been identified. Mobility measurements for (NaCl)nCl- clusters have revealed multiple isomers with the same fcc packing but different j x k x l dimensions. Metastable (NaCl)nCl- geometries isomerize on the timescale of the mobility measurements (hundreds of milliseconds). Rate constants and activation energies for the isomerization processes are extracted directly from the mobility measurements; the activation energies are found to be remarkably low. Indium and silicon cluster mobilities are found to be sensitive to the degree of electron spillout from the surface of the cluster, as revealed in differences in the anionic and cationic cluster mobilities. Mobility measurements of solvent-free biological molecules reveal important information about their intramolecular forces. Due to the gentle ion sampling in the high resolution ion mobility apparatus electrospray interface, high resolution mobilities of gas-phase proteins are found to be sensitive to the nature of the electrosprayed solution. Although calculations have shown that neutral polyalanine in vacuo is mostly helical, gas- phase polyalanine ions, AnH+, are found

  4. Differences in innate immune responses to H5N1 highly pathogenic avian influenza virus infection between Pekin, Muscovy and Mallard ducks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ducks have been implicated in the dissemination and evolution of H5N1 highly pathogenic avian influenza (HPAI) viruses. However, differences in pathogenicity and response to vaccination have been observed between different duck species. In this study we examined the pathogenicity of H5N1 HPAI viru...

  5. Inactivation of foodborne pathogens in ground beef by cooking with highly controlled radio frequency energy.

    PubMed

    Schlisselberg, Dov B; Kler, Edna; Kalily, Emmanuel; Kisluk, Guy; Karniel, Ohad; Yaron, Sima

    2013-01-01

    The consumer demand for fresh tasting, high quality, low salt, preservative-free meals which require minimal preparation time magnifies the safety concern and emphasizes the need to use innovative technologies for food processing. A modern technique to uniformly heat and cook foods is based on a combination of convection and controlled radio frequency (RF) energy. However any advantage conferred on meat cooked by this method would be lost if application of the technology results in decreased safety. Our main goal was to study the inactivation efficacy of this method of cooking against pathogens in ground meat in comparison to standard convection cooking. Meat balls were artificially inoculated with GFP expressing Escherichia coli, Salmonella Typhimurium and Listeria monocytogenes as well as spores of Bacillus cereus and Bacillus thuringiensis and cooked by convection heating (220°C, 40 min), by using energy generated from frequencies in the RF bandwidth (RF cooking, 7.5 min) or by combined heating (5.5 min), until the center temperature of each sample reached 73°C. The mean reductions in total indigenous bacteria obtained by RF and convection were 2.8 and 2.5 log CFU/g, respectively. Cooking of meat balls with convection reduced the E. coli population (8 log CFU/g) by 5.5 log CFU/g, whilst treatment with RF reduced E. coli population to undetectable levels. The mean reductions of S. Typhimurium obtained by RF and convection were 5.7 and 6.5 log CFU/g, respectively. The combined treatment reduced the Salmonella population to undetectable levels. In contrast, L. monocytogenes was poorly affected by RF cooking. The mean reduction of L. monocytogenes obtained by RF energy was 0.4 log CFU/g, while convection cooking resulted in undetectable levels. Interestingly, the combined treatment also resulted with undetectable levels of Listeria although time of cooking was reduced by 86%. One-step cooking had negligible effects on the Bacillus spores and therefore a 2-step

  6. Benefits of a European Project on Diagnostics of Highly Pathogenic Agents and Assessment of Potential “Dual Use” Issues

    PubMed Central

    Grunow, Roland; Ippolito, G.; Jacob, D.; Sauer, U.; Rohleder, A.; Di Caro, A.; Iacovino, R.

    2014-01-01

    Quality assurance exercises and networking on the detection of highly infectious pathogens (QUANDHIP) is a joint action initiative set up in 2011 that has successfully unified the primary objectives of the European Network on Highly Pathogenic Bacteria (ENHPB) and of P4-laboratories (ENP4-Lab) both of which aimed to improve the efficiency, effectiveness, and response capabilities of laboratories directed at protecting the health of European citizens against high consequence bacteria and viruses of significant public health concern. Both networks have established a common collaborative consortium of 37 nationally and internationally recognized institutions with laboratory facilities from 22 European countries. The specific objectives and achievements include the initiation and establishment of a recognized and acceptable quality assurance scheme, including practical external quality assurance exercises, comprising living agents, that aims to improve laboratory performance, accuracy, and detection capabilities in support of patient management and public health responses; recognized training schemes for diagnostics and handling of highly pathogenic agents; international repositories comprising highly pathogenic bacteria and viruses for the development of standardized reference material; a standardized and transparent Biosafety and Biosecurity strategy protecting healthcare personnel and the community in dealing with high consequence pathogens; the design and organization of response capabilities dealing with cross-border events with highly infectious pathogens including the consideration of diagnostic capabilities of individual European laboratories. The project tackled several sensitive issues regarding Biosafety, Biosecurity and “dual use” concerns. The article will give an overview of the project outcomes and discuss the assessment of potential “dual use” issues. PMID:25426479

  7. Faculty Mobility and Its Influence on New Jersey High School Proficiency Assessment Scores

    ERIC Educational Resources Information Center

    Graziano, Dana; Babo, Gerard

    2014-01-01

    This paper presents results from an examination of the relationships between high school (HS) faculty mobility and 2009-2010 New Jersey High School Proficiency Assessment (HSPA) Math and Language Arts Literacy test results. Variables found to have an influence on standardized test scores in the extant literature were evaluated and reported.…

  8. High electron mobility ZnO film for high-performance inverted polymer solar cells

    NASA Astrophysics Data System (ADS)

    Lv, Peiwen; Chen, Shan-Ci; Zheng, Qingdong; Huang, Feng; Ding, Kai

    2015-04-01

    High-quality ZnO films (ZnO-MS) are prepared via magnetron sputtering deposition with a high mobility of about 2 cm2/(V.s) and are used as electron transport layer for inverted polymer solar cells (PSCs) with polymer poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b']dithiophene-co-3-fluorothieno[3,4-b]thiophene-2-carboxylate]:[6,6]-phenyl C71-butyric acid methyl ester as the active layer. A significant improvement of JSC, about 20% enhancement in contrast to the devices built on sol-gel derived ZnO film (ZnO-Sol), is found in the ZnO-MS based device. High performance ZnO-MS based PSCs exhibit power conversion efficiency (PCE) up to 8.55%, which is much better than the device based on ZnO-Sol (PCE = 7.78%). Further research on cathode materials is promising to achieve higher performance.

  9. High electron mobility ZnO film for high-performance inverted polymer solar cells

    SciTech Connect

    Lv, Peiwen; Chen, Shan-Ci; Zheng, Qingdong; Huang, Feng Ding, Kai

    2015-04-20

    High-quality ZnO films (ZnO-MS) are prepared via magnetron sputtering deposition with a high mobility of about 2 cm{sup 2}/(V·s) and are used as electron transport layer for inverted polymer solar cells (PSCs) with polymer poly[4,8-bis(5-(2-ethylhexyl)thiophen-2-yl)benzo[1,2-b:4,5-b′] dithiophene-co-3-fluorothieno[3,4-b]thiophene-2-carboxylate]:[6,6]-phenyl C71-butyric acid methyl ester as the active layer. A significant improvement of J{sub SC}, about 20% enhancement in contrast to the devices built on sol-gel derived ZnO film (ZnO-Sol), is found in the ZnO-MS based device. High performance ZnO-MS based PSCs exhibit power conversion efficiency (PCE) up to 8.55%, which is much better than the device based on ZnO-Sol (PCE = 7.78%). Further research on cathode materials is promising to achieve higher performance.

  10. Detection of H5N1 high pathogenicity avian influenza virus in meat and tracheal samples from experimentally infected chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Asian H5N1 highly pathogenic avian influenza (HPAI) virus causes a systemic disease with high mortality of poultry and is potentially zoonotic. In both chickens and ducks, the virus has been demonstrated to replicate in both cardiac and skeletal muscle cells. Experimentally, H5N1 HPAI virus ha...

  11. Highly pathogenic H5N1 avian influenza viruses differentially affect gene expression in primary chicken embryo fibroblasts

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Highly pathogenic avian influenza viruses cause severe clinical disease associated with high mortality in chickens and other gallinaceous species. However, the mechanism by which different strains of avian influenza viruses overcome host response in birds is still unclear. In the present study, ch...

  12. High mobility Single Layer Epitaxial Graphene on 4H-SiC (000-1)

    NASA Astrophysics Data System (ADS)

    Hu, Yike; Guo, Zelei; Ruan, Ming; Hankinson, John; Palmer, James; Zhang, Baiqian; Dong, Rui; Kunc, Jan; Berger, Claire; Deheer, Walt

    2012-02-01

    Multi-layer Epitaxial Graphene on 4H-SiC (000-1) has demonstrated very high mobility up to˜27,000 cm^2/Vs [1]. Recently single layer graphene grown by the Confinement Control Growth method [2] exhibits mobility up to ˜ 25,000cm^2/V.s at 4K and 13,000 cm^2/V.s at 300K with p=3 x 10^12 cm-2 The relation between Raman G peak features (FWHM and position) and carrier density of Epitaxial Graphene on carbon face is revealed. Quantum Hall Effect [3] is observed both for p and n type carriers on top gated sample. This indicates that top gated single layer graphene can be produced on the Carbon face with high quality and high carrier mobility. [4pt] [1] Science 312, 1191 (2006) [0pt] [2] PNAS 108 (41) 16900 (2011) [0pt] [3] APL 95, 223108 (2009)

  13. Record high hole mobility in polymer semiconductors via side-chain engineering.

    PubMed

    Kang, Il; Yun, Hui-Jun; Chung, Dae Sung; Kwon, Soon-Ki; Kim, Yun-Hi

    2013-10-01

    Charge carrier mobility is still the most challenging issue that should be overcome to realize everyday organic electronics in the near future. In this Communication, we show that introducing smart side-chain engineering to polymer semiconductors can facilitate intermolecular electronic communication. Two new polymers, P-29-DPPDBTE and P-29-DPPDTSE, which consist of a highly conductive diketopyrrolopyrrole backbone and an extended branching-position-adjusted side chain, showed unprecedented record high hole mobility of 12 cm(2)/(V·s). From photophysical and structural studies, we found that moving the branching position of the side chain away from the backbone of these polymers resulted in increased intermolecular interactions with extremely short π-π stacking distances, without compromising solubility of the polymers. As a result, high hole mobility could be achieved even in devices fabricated using the polymers at room temperature. PMID:24053786

  14. Neuropathogenesis of a highly pathogenic avian influenza virus (H7N1) in experimentally infected chickens

    PubMed Central

    2011-01-01

    In order to understand the mechanism of neuroinvasion of a highly pathogenic avian influenza virus (HPAIV) into the central nervous system (CNS) of chickens, specific pathogen free chickens were inoculated with a H7N1 HPAIV. Blood, cerebrospinal fluid (CSF), nasal cavity and brain tissue samples were obtained from 1 to 4 days post-inoculation (dpi) of infected and control chickens. Viral antigen topographical distribution, presence of influenza A virus receptors in the brain, as well as, the role of the olfactory route in virus CNS invasion were studied using different immunohistochemistry techniques. Besides, viral RNA load in CSF and blood was quantified by means of a quantitative real-time reverse transcription-polymerase chain reaction. Viral antigen was observed widely distributed in the CNS, showing bilateral and symmetrical distribution in the nuclei of the diencephalon, mesencephalon and rhombencephalon. Viral RNA was detected in blood and CSF at one dpi, indicating that the virus crosses the blood-CSF-barrier early during infection. This early dissemination is possibly favoured by the presence of Siaα2,3 Gal and Siaα2,6 Gal receptors in brain vascular endothelial cells, and Siaα2,3 Gal receptors in ependymal and choroid plexus cells. No viral antigen was observed in olfactory sensory neurons, while the olfactory bulb showed only weak staining, suggesting that the virus did not use this pathway to enter into the brain. The sequence of virus appearance and the topographical distribution of this H7N1 HPAIV indicate that the viral entry occurs via the haematogenous route, with early and generalized spreading through the CSF. PMID:21982125

  15. High Electron Mobility Transistors For Millimeter Wave And High Speed Digital IC Applications

    NASA Astrophysics Data System (ADS)

    Gupta, Aditya K.; Higgins, J. A.; Lee, Chien-Ping

    1988-02-01

    High Electron Mobility Transistors (HEMTs) are currently regarded as the most promising three-terminal devices for ultra-high-speed digital and monolithic millimeter-wave integrated circuits. In their most basic form, these devices consist of a GaAs-MESFET-like FET fabricated on a (A1,Ga)As/GaAs epitaxial layer. The (A1,Ga)As layer is highly doped n-type and the GaAs layer is undoped. Due to the lower electron affinity of (A1,Ga)As, free electrons diffuse out of the doped layer into undoped GaAs where they form a two-dimensional electron gas near the heterointerface. Since the electrons and ionized donors are spatially separated, ionized impurity scattering is reduced and electron transport properties at the heterointerface are comparable to pure GaAs. FETs fabricated on these hetero-junctions offer many advantages such as (i) a small gate-to-channel separation which leads to extremely high transconductances; (ii) high f due to improved electron transport properties; (iii) a small source resistance; and (ivy a small saturation voltage. The benefits improve substantially upon cooling the device. In a mere seven years, HEMT technology has evolved from simple ring oscillators to circuits of LSI complexity such as 16K SRAMs. The speed performance demonstrated by this relatively immature technology has already surpassed all other semiconductor technologies. Ring oscillator gate delays of 5.8 ps at 77K and 10.2 ps at 300K have been achieved using'0.35 μm gate length devices. In the analog domain, HEMTs are the leaders in low noise and high gain amplification. At room temperatures, devices with a noise figure of 2.4 dB at 62 GHz and fmax > 250 GHz have been demonstrated.

  16. Comparative Respiratory Pathogenicity and Dynamic Tissue Distribution of Chinese Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus and its Attenuated Strain in Piglets.

    PubMed

    Liu, C; Zhang, W; Gong, W; Zhang, D; She, R; Xu, B; Ning, Y

    2015-07-01

    The outbreak of highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS) in 2006 devastated the Chinese swine industry. HP-PRRS virus is still the predominant strain in mainland China, rather than the classical PRRSV strain, and the attenuated live vaccine remains the preferred choice for protecting piglets against HP-PRRSV infection. To fully evaluate the safety of strain GDr180, the 180th attenuated virus of the HP-PRRSV strain GD, we used clinicopathological, microscopical, ultrastructural, serological and molecular biological methods to assess the different clinical manifestations and respiratory characteristics of piglets inoculated with HP-PRRSV strain GD or strain GDr180. The 5-week-old piglets inoculated with strain GD displayed marked clinical signs, including fever, anorexia, dyspnoea and tachypnoea. Significant interstitial pneumonia was present, characterized by thickened alveolar septa infiltrated with mononuclear cells and cell debris. However, the piglets inoculated with strain GDr180 and the negative control piglets showed neither clinical signs nor microscopical or ultrastructural lesions. Ultrastructural observation of the piglets' tracheas and examination of the dynamic tissue distributions of PRRSV strain GD and attenuated strain GDr180, by immunohistochemistry and fluorescence quantitative reverse transcription-polymerase chain reaction, confirmed significant differences in their pathogenicity and distribution in the respiratory systems of piglets. The differences in pathogenicity are attributable to the different severity of the pathological changes in the pigs inoculated with the two strains. Thus, the HP-PRRSV GDr180 strain is practically harmless to the respiratory systems of piglets and may be a safe candidate for inducing immunity against HP-PRRS. PMID:25980840

  17. High Pathogenicity of Wild-Type Measles Virus Infection in CD150 (SLAM) Transgenic Mice

    PubMed Central

    Sellin, Caroline I.; Davoust, Nathalie; Guillaume, Vanessa; Baas, Dominique; Belin, Marie-Françoise; Buckland, Robin; Wild, T. Fabian; Horvat, Branka

    2006-01-01

    Measles virus (MV) infection causes an acute childhood disease, associated in certain cases with infection of the central nervous system and development of a severe neurological disease. We have generated transgenic mice ubiquitously expressing the human protein SLAM (signaling lymphocytic activation molecule), or CD150, recently identified as an MV receptor. In contrast to all other MV receptor transgenic models described so far, in these mice infection with wild-type MV strains is highly pathogenic. Intranasal infection of SLAM transgenic suckling mice leads to MV spread to different organs and the development of an acute neurological syndrome, characterized by lethargy, seizures, ataxia, weight loss, and death within 3 weeks. In addition, in this model, vaccine and wild-type MV strains can be distinguished by virulence. Furthermore, intracranial MV infection of adult transgenic mice generates a subclinical infection associated with a high titer of MV-specific antibodies in the serum. Finally, to analyze new antimeasles therapeutic approaches, we created a recombinant soluble form of SLAM and demonstrated its important antiviral activity both in vitro and in vivo. Taken together, our results show the high susceptibility of SLAM transgenic mice to MV-induced neurological disease and open new perspectives for the analysis of the implication of SLAM in the neuropathogenicity of other morbilliviruses, which also use this molecule as a receptor. Moreover, this transgenic model, in allowing a simple readout of the efficacy of an antiviral treatment, provides unique experimental means to test novel anti-MV preventive and therapeutic strategies. PMID:16775330

  18. Characterizing ncRNAs in Human Pathogenic Protists Using High-Throughput Sequencing Technology

    PubMed Central

    Collins, Lesley Joan

    2011-01-01

    ncRNAs are key genes in many human diseases including cancer and viral infection, as well as providing critical functions in pathogenic organisms such as fungi, bacteria, viruses, and protists. Until now the identification and characterization of ncRNAs associated with disease has been slow or inaccurate requiring many years of testing to understand complicated RNA and protein gene relationships. High-throughput sequencing now offers the opportunity to characterize miRNAs, siRNAs, small nucleolar RNAs (snoRNAs), and long ncRNAs on a genomic scale, making it faster and easier to clarify how these ncRNAs contribute to the disease state. However, this technology is still relatively new, and ncRNA discovery is not an application of high priority for streamlined bioinformatics. Here we summarize background concepts and practical approaches for ncRNA analysis using high-throughput sequencing, and how it relates to understanding human disease. As a case study, we focus on the parasitic protists Giardia lamblia and Trichomonas vaginalis, where large evolutionary distance has meant difficulties in comparing ncRNAs with those from model eukaryotes. A combination of biological, computational, and sequencing approaches has enabled easier classification of ncRNA classes such as snoRNAs, but has also aided the identification of novel classes. It is hoped that a higher level of understanding of ncRNA expression and interaction may aid in the development of less harsh treatment for protist-based diseases. PMID:22303390

  19. High-throughput real-time electrochemical monitoring of LAMP for pathogenic bacteria detection.

    PubMed

    Safavieh, Mohammadali; Ahmed, Minhaz Uddin; Ng, Andy; Zourob, Mohammed

    2014-08-15

    One of the significant challenges in healthcare is the development of point-of-care (POC) diagnostics. POC diagnostics require low-cost devices that offer portability, simplicity in operation and the ability for high-throughput and quantitative analysis. Here, we present a novel roll-to-roll ribbon fluid-handling device for electrochemical real-time monitoring of nucleic acid (NA) amplification and bacteria detection. The device rendered loop-mediated isothermal amplification (LAMP) and real-time electrochemical detection based on the interaction between LAMP amplicon and the redox-reactive osmium complex. We have shown the detection of 30CFU/ml of Escherichia coli (in the range between 30 and 3×10(7)CFU/ml) and 200CFU/ml of Staphylococcus aureus (in the range of 200-2×10(5)CFU/ml) cultured samples in both real-time and end point detection. This device can be used for the detection of various Gram-negative and a number of Gram-positive bacterial pathogens with high sensitivity and specificity in a high-throughput format. Using a roll-to-roll cassette approach, we could detect 12 samples in one assay. Since the LAMP and electrochemical analysis are implemented within sealed flexible biochips, time-consuming processing steps are not required and the risk of contamination is significantly reduced. PMID:24632135

  20. From computational discovery to experimental characterization of a high hole mobility organic crystal

    PubMed Central

    Sokolov, Anatoliy N.; Atahan-Evrenk, Sule; Mondal, Rajib; Akkerman, Hylke B.; Sánchez-Carrera, Roel S.; Granados-Focil, Sergio; Schrier, Joshua; Mannsfeld, Stefan C.B.; Zoombelt, Arjan P.; Bao, Zhenan; Aspuru-Guzik, Alán

    2011-01-01

    For organic semiconductors to find ubiquitous electronics applications, the development of new materials with high mobility and air stability is critical. Despite the versatility of carbon, exploratory chemical synthesis in the vast chemical space can be hindered by synthetic and characterization difficulties. Here we show that in silico screening of novel derivatives of the dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene semiconductor with high hole mobility and air stability can lead to the discovery of a new high-performance semiconductor. On the basis of estimates from the Marcus theory of charge transfer rates, we identified a novel compound expected to demonstrate a theoretic twofold improvement in mobility over the parent molecule. Synthetic and electrical characterization of the compound is reported with single-crystal field-effect transistors, showing a remarkable saturation and linear mobility of 12.3 and 16 cm2 V−1 s−1, respectively. This is one of the very few organic semiconductors with mobility greater than 10 cm2 V−1 s−1 reported to date. PMID:21847111

  1. Importation and Recombination Are Responsible for the Latest Emergence of Highly Pathogenic Porcine Reproductive and Respiratory Syndrome Virus in China

    PubMed Central

    Zhao, Kuan; Ye, Chao; Chang, Xiao-Bo; Jiang, Cheng-Gang; Wang, Shu-Jie; Cai, Xue-Hui; Tong, Guang-Zhi; Tian, Zhi-Jun

    2015-01-01

    In China, a majority of the highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRSV) strains were seeded by the 2006 outbreak. However, the most recently emerged (2013-2014) HP-PRRSV strain has a very different genetic background. It is a NADC30-like PRRSV strain recently introduced from North America that has undergone genetic exchange with the classic HP-PRRSV strains in China. Subsequent isolation and characterization of this variant suggest high pathogenicity, so it merits special attention in control and vaccine strategies. PMID:26246582

  2. "It's a Way of Life for Us": High Mobility and High Achievement in Department of Defense Schools.

    ERIC Educational Resources Information Center

    Smrekar, Claire E.; Owens, Debra E.

    2003-01-01

    Examines the academic performance of students in U.S. Department of Defense Education Activity (DoDEA) schools, which have high student mobility. Some observers contend that these students' high achievement is a function of their middle class family and community characteristics. Asserts that DoDEA schools simultaneously "do the right things" and…

  3. 25th anniversary article: key points for high-mobility organic field-effect transistors.

    PubMed

    Dong, Huanli; Fu, Xiaolong; Liu, Jie; Wang, Zongrui; Hu, Wenping

    2013-11-20

    Remarkable progress has been made in developing high performance organic field-effect transistors (OFETs) and the mobility of OFETs has been approaching the values of polycrystalline silicon, meeting the requirements of various electronic applications from electronic papers to integrated circuits. In this review, the key points for development of high mobility OFETs are highlighted from aspects of molecular engineering, process engineering and interface engineering. The importance of other factors, such as impurities and testing conditions is also addressed. Finally, the current challenges in this field for practical applications of OFETs are further discussed. PMID:24105677

  4. Clinical Evaluation of the New High-Throughput Luminex NxTAG Respiratory Pathogen Panel Assay for Multiplex Respiratory Pathogen Detection.

    PubMed

    Chen, Jonathan H K; Lam, Ho-Yin; Yip, Cyril C Y; Wong, Sally C Y; Chan, Jasper F W; Ma, Edmond S K; Cheng, Vincent C C; Tang, Bone S F; Yuen, Kwok-Yung

    2016-07-01

    A broad range of viral and bacterial pathogens can cause acute respiratory tract infection. For rapid detection of a broad respiratory pathogen spectrum, multiplex real-time PCR is ideal. This study evaluated the performance of the new Luminex NxTAG Respiratory Pathogen Panel (NxTAG-RPP) in comparison with the BioFire FilmArray Respiratory Panel (FA-RP) or singleplex real-time PCR as reference. A total of 284 clinical respiratory specimens and 3 influenza A/H7N9 viral culture samples were tested. All clinical specimens were processed and analyzed in parallel using NxTAG-RPP and the reference standard method. The H7N9 viral culture samples were tested using NxTAG-RPP only. Overall, the NxTAG-RPP demonstrated ≥93% sensitivity and specificity for all respiratory targets except human coronavirus OC43 (HCoV-OC43) and HCoV-HKU1. The H7N9 virus was detected by the influenza A virus matrix gene target, while other influenza A virus subtyping gene targets in the panel remained negative. Complete concordance between NxTAG-RPP and FA-RP was observed in 98.8% (318/322) of positive results (kappa = 0.92). Substantial agreement was found for most respiratory targets, but significant differences were observed in human metapneumovirus (P = 0.001) and parainfluenza virus type 3 (P = 0.031). NxTAG-RPP has a higher sample throughput than FA-RP (96 samples versus 1 sample per run) while the turnaround times for NxTAG-RPP and FA-RP were 5 h (up to 96 samples) and 1 h (for one sample), respectively. Overall, NxTAG-RPP demonstrated good diagnostic performance for most respiratory pathogens. The high sample throughput with reasonable turnaround time of this new assay makes it a suitable multiplex platform for routine screening of respiratory specimens in hospital-based laboratories. PMID:27122380

  5. Low-temperature high-mobility amorphous IZO for silicon heterojunction solar cells

    DOE PAGESBeta

    Morales-Masis, Monica; Martin De Nicolas, Silvia; Holovsky, Jakub; De Wolf, Stefaan; Ballif, Christophe

    2015-07-13

    Parasitic absorption in the transparent conductive oxide (TCO) front electrode is one of the limitations of silicon heterojunction (SHJ) solar cells efficiency. To avoid such absorption while retaining high conductivity, TCOs with high electron mobility are preferred over those with high carrier density. Here, we demonstrate improved SHJ solar cell efficiencies by applying high-mobility amorphous indium zinc oxide (a-IZO) as the front TCO. We sputtered a-IZO at low substrate temperature and low power density and investigated the optical and electrical properties, as well as subband tail formation-quantified by the Urbach energy (EU)-as a function of the sputtering oxygen partial pressure.more » We obtain an EU as low as 128 meV for films with the highest Hall mobility of 60 cm2/Vs. When comparing the performance of a-IZO films with indium tin oxide (ITO) and hydrogenated indium oxide (IO:H), we find that IO:H (115 cm2/Vs) exhibits a similar EU of 130 meV, while ITO (25 cm2/Vs) presents a much larger EU of up to 270 meV. The high film quality, indicated by the low EU, the high mobility, and low free carrier absorption of the developed a-IZO electrodes, result in a significant current improvement, achieving conversion efficiencies over 21.5%, outperforming those with standard ITO.« less

  6. An easy operating pathogen microarray (EOPM) platform for rapid screening of vertebrate pathogens

    PubMed Central

    2013-01-01

    Background Infectious diseases emerge frequently in China, partly because of its large and highly mobile population. Therefore, a rapid and cost-effective pathogen screening method with broad coverage is required for prevention and control of infectious diseases. The availability of a large number of microbial genome sequences generated by conventional Sanger sequencing and next generation sequencing has enabled the development of a high-throughput high-density microarray platform for rapid large-scale screening of vertebrate pathogens. Methods An easy operating pathogen microarray (EOPM) was designed to detect almost all known pathogens and related species based on their genomic sequences. For effective identification of pathogens from EOPM data, a statistical enrichment algorithm has been proposed, and further implemented in a user-friendly web-based interface. Results Using multiple probes designed to specifically detect a microbial genus or species, EOPM can correctly identify known pathogens at the species or genus level in blinded testing. Despite a lower sensitivity than PCR, EOPM is sufficiently sensitive to detect the predominant pathogens causing clinical symptoms. During application in two recent clinical infectious disease outbreaks in China, EOPM successfully identified the responsible pathogens. Conclusions EOPM is an effective surveillance platform for infectious diseases, and can play an important role in infectious disease control. PMID:24053492

  7. Ionic Wind Phenomenon and Charge Carrier Mobility in Very High Density Argon Corona Discharge Plasma

    NASA Astrophysics Data System (ADS)

    Nur, M.; Bonifaci, N.; Denat, A.

    2014-04-01

    Wind ions phenomenon has been observed in the high density argon corona discharge plasma. Corona discharge plasma was produced by point to plane electrodes and high voltage DC. Light emission from the recombination process was observed visually. The light emission proper follow the electric field lines that occur between point and plane electrodes. By using saturation current, the mobilities of non-thermal electrons and ions have been obtained in argon gas and liquid with variation of density from 2,5 1021 to 2 1022 cm-3. In the case of ions, we found that the behaviour of the apparent mobility inversely proportional to the density or follow the Langevin variation law. For non-thermal electron, mobility decreases and approximately follows a variation of Langevin type until the density <= 0,25 the critical density of argon.

  8. Mechanical flip-chip for ultra-high electron mobility devices

    SciTech Connect

    Bennaceur, Keyan; Schmidt, Benjamin A.; Gaucher, Samuel; Laroche, Dominique; Lilly, Michael P.; Reno, John L.; West, Ken W.; Pfeiffer, Loren N.; Gervais, Guillaume

    2015-09-22

    In this study, electrostatic gates are of paramount importance for the physics of devices based on high-mobility two-dimensional electron gas (2DEG) since they allow depletion of electrons in selected areas. This field-effect gating enables the fabrication of a wide range of devices such as, for example, quantum point contacts (QPC), electron interferometers and quantum dots. To fabricate these gates, processing is usually performed on the 2DEG material, which is in many cases detrimental to its electron mobility. Here we propose an alternative process which does not require any processing of the 2DEG material other than for the ohmic contacts. This approach relies on processing a separate wafer that is then mechanically mounted on the 2DEG material in a flip-chip fashion. This technique proved successful to fabricate quantum point contacts on both GaAs/AlGaAs materials with both moderate and ultra-high electron mobility.

  9. Mechanical Flip-Chip for Ultra-High Electron Mobility Devices

    PubMed Central

    Bennaceur, Keyan; Schmidt, Benjamin A.; Gaucher, Samuel; Laroche, Dominique; Lilly, Michael P.; Reno, John L.; West, Ken W.; Pfeiffer, Loren N.; Gervais, Guillaume

    2015-01-01

    Electrostatic gates are of paramount importance for the physics of devices based on high-mobility two-dimensional electron gas (2DEG) since they allow depletion of electrons in selected areas. This field-effect gating enables the fabrication of a wide range of devices such as, for example, quantum point contacts (QPC), electron interferometers and quantum dots. To fabricate these gates, processing is usually performed on the 2DEG material, which is in many cases detrimental to its electron mobility. Here we propose an alternative process which does not require any processing of the 2DEG material other than for the ohmic contacts. This approach relies on processing a separate wafer that is then mechanically mounted on the 2DEG material in a flip-chip fashion. This technique proved successful to fabricate quantum point contacts on both GaAs/AlGaAs materials with both moderate and ultra-high electron mobility. PMID:26391400

  10. Mechanical Flip-Chip for Ultra-High Electron Mobility Devices.

    PubMed

    Bennaceur, Keyan; Schmidt, Benjamin A; Gaucher, Samuel; Laroche, Dominique; Lilly, Michael P; Reno, John L; West, Ken W; Pfeiffer, Loren N; Gervais, Guillaume

    2015-01-01

    Electrostatic gates are of paramount importance for the physics of devices based on high-mobility two-dimensional electron gas (2DEG) since they allow depletion of electrons in selected areas. This field-effect gating enables the fabrication of a wide range of devices such as, for example, quantum point contacts (QPC), electron interferometers and quantum dots. To fabricate these gates, processing is usually performed on the 2DEG material, which is in many cases detrimental to its electron mobility. Here we propose an alternative process which does not require any processing of the 2DEG material other than for the ohmic contacts. This approach relies on processing a separate wafer that is then mechanically mounted on the 2DEG material in a flip-chip fashion. This technique proved successful to fabricate quantum point contacts on both GaAs/AlGaAs materials with both moderate and ultra-high electron mobility. PMID:26391400

  11. Experimental infection of SPF and Korean native chickens with highly pathogenic avian influenza virus (H5N8).

    PubMed

    Lee, Eun-Kyoung; Song, Byung-Min; Kang, Hyun-Mi; Woo, Sang-Hee; Heo, Gyeong-Beom; Jung, Suk Chan; Park, Yong Ho; Lee, Youn-Jeong; Kim, Jae-Hong

    2016-05-01

    In 2014, an H5N8 outbreak of highly pathogenic avian influenza (HPAI) occurred in South Korea. The H5N8 strain produced mild to moderate clinical signs and mortality rates in commercial chicken farms, especially Korean native chicken farms. To understand the differences between their pathogenicity in SPF chicken and Korean native chicken., we evaluated the mean bird lethal doses (BLD50) of the Korean representative H5N8 virus (A/broiler duck/Korea/Buan2/2014) The BLD50values of the H5N8 virus were 10(5.3)EID50and 10(6.7)EID50in SPF and Korean native chickens, respectively. In addition, the mean death time was much longer, and the viral titers in tissues of H5N8-infected chickens were significantly lower, in the Korean group than in the SPF group. These features of the H5N8 virus likely account for its mild-to-moderate pathogenicity in commercial chicken farms, especially Korean native chicken flocks, despite the fact that it is a highly pathogenic virus according to the OIE criteria. To improve current understanding and management of HPAI, pathogenic characterization of novel emerging viruses should be performed by natural route in major poultry species in each country. PMID:26933235

  12. The Use of High Pressure Freezing and Freeze Substitution to Study Host-Pathogen Interactions in Fungal Diseases of Plants

    NASA Astrophysics Data System (ADS)

    Mims, C. W.; Celio, Gail J.; Richardson, Elizabeth A.

    2003-12-01

    This article reports on the use of high pressure freezing followed by freeze substitution (HPF/FS) to study ultrastructural details of host pathogen interactions in fungal diseases of plants. The specific host pathogen systems discussed here include a powdery mildew infection of poinsettia and rust infections of daylily and Indian strawberry. The three pathogens considered here all attack the leaves of their hosts and produce specialized hyphal branches known as haustoria that invade individual host cells without killing them. We found that HPF/FS provided excellent preservation of both haustoria and host cells for all three host pathogen systems. Preservation of fungal and host cell membranes was particularly good and greatly facilitated the detailed study of host pathogen interfaces. In some instances, HPF/FS provided information that was not available in samples prepared for study using conventional chemical fixation. On the other hand, we did encounter various problems associated with the use of HPF/FS. Examples included freeze damage of samples, inconsistency of fixation in different samples, separation of plant cell cytoplasm from cell walls, breakage of cell walls and membranes, and splitting of thin sections. However, we believe that the outstanding preservation of ultrastructural details afforded by HPF/FS significantly outweighs these problems and we highly recommend the use of this fixation protocol for future studies of fungal host-plant interactions.

  13. Unraveling the Architecture and Structural Dynamics of Pathogens by High-Resolution in vitro Atomic Force Microscopy

    SciTech Connect

    Malkin, A J; Plomp, M; Leighton, T J; McPherson, A; Wheeler, K E

    2005-04-12

    Progress in structural biology very much depends upon the development of new high-resolution techniques and tools. Despite decades of study of viruses, bacteria and bacterial spores and their pressing importance in human medicine and biodefense, many of their structural properties are poorly understood. Thus, characterization and understanding of the architecture of protein surface and internal structures of pathogens is critical to elucidating mechanisms of disease, immune response, physicochemical properties, environmental resistance and development of countermeasures against bioterrorist agents. Furthermore, even though complete genome sequences are available for various pathogens, the structure-function relationships are not understood. Because of their lack of symmetry and heterogeneity, large human pathogens are often refractory to X-ray crystallographic analysis or reconstruction by cryo-electron microscopy (cryo-EM). An alternative high-resolution method to examine native structure of pathogens is atomic force microscopy (AFM), which allows direct visualization of macromolecular assemblies at near-molecular resolution. The capability to image single pathogen surfaces at nanometer scale in vitro would profoundly impact mechanistic and structural studies of pathogenesis, immunobiology, specific cellular processes, environmental dynamics and biotransformation.

  14. Generation of High Resolution and High Precision Orthorectified Road Imagery from Mobile Mapping System

    NASA Astrophysics Data System (ADS)

    Sakamoto, M.; Tachibana, K.; Shimamura, H.

    2012-07-01

    In this paper, a novel technique to generate a high resolution and high precision Orthorectified Road Imagery (ORI) by using spatial information acquired from a Mobile Mapping System (MMS) is introduced. The MMS was equipped with multiple sensors such as GPS, IMU, odometer, 2-6 digital cameras and 2-4 laser scanners. In this study, a Triangulated Irregular Network (TIN) based approach, similar to general aerial photogrammetry, was adopted to build a terrain model in order to generate ORI with high resolution and high geometric precision. Compared to aerial photogrammetry, there are several issues that are needed to be addressed. ORI is generated by merging multiple time sequence images of a short section. Hence, the influence of occlusion due to stationary objects, such as telephone poles, trees, footbridges, or moving objects, such as vehicles, pedestrians are very significant. Moreover, influences of light falloff at the edges of cameras, tone adjustment among images captured from different cameras or a round trip data acquisition of the same path, and time lag between image exposure and laser point acquisition also need to be addressed properly. The proposed method was applied to generate ORI with 1 cm resolution, from the actual MMS data sets. The ORI generated by the proposed technique was more clear, occlusion free and with higher resolution compared to the conventional orthorectified coloured point cloud imagery. Moreover, the visual interpretation of road features from the ORI was much easier. In addition, the experimental results also validated the effectiveness of proposed radiometric corrections. In occluded regions, the ORI was compensated by using other images captured from different angles. The validity of the image masking process, in the occluded regions, was also ascertained.

  15. Biosecurity aspects and pathogen inactivation in acidified high risk animal by-products.

    PubMed

    Vinnerås, Björn; Samuelson, Annika; Emmoth, Eva; Nyberg, Karin A; Albihn, Ann

    2012-01-01

    The aim of the study was to investigate the effects of formic acid addition to ground high risk animal by-products (ABP 1) in terms of stabilization and pathogen inactivation and to evaluate the biosecurity risk connected with the ABP 1 based combustion fuel Biomal. Laboratory studies were performed on the persistence of Salmonella Typhimurium, Bacillus cereus spores, porcine herpes virus, avian influenza virus, bovine viral diarrhea virus, equine rhinitis A virus and porcine parvovirus in Biomal at different storage times. It was shown that Salmonella and enveloped viruses were inactivated within 1 day (24 h). Bacillus cereus spores were not reduced during 147 days and the non-enveloped virus porcine parvovirus was still detected after 168 days of storage. The conclusion that can be drawn from the study is that transmission of some highly contagious diseases such as foot-and-mouth-disease, swine vesicular disease and egg drop syndrome, caused by non-enveloped viruses, may follow accidental leakages of Biomal. In addition, there is a risk of transmission of the diseases anthrax and black leg, caused by sporulating bacteria. PMID:22506709

  16. Use of a New High Resolution Melting Method for Genotyping Pathogenic Leptospira spp.

    PubMed Central

    Naze, Florence; Desvars, Amélie; Picardeau, Mathieu; Bourhy, Pascale; Michault, Alain

    2015-01-01

    Background Leptospirosis is a worldwide zoonosis that is endemic in tropical areas, such as Reunion Island. The species Leptospira interrogans is the primary agent in human infections, but other pathogenic species, such as L. kirschner and L. borgpetersenii, are also associated with human leptospirosis. Methods and Findings In this study, a melting curve analysis of the products that were amplified with the primer pairs lfb1 F/R and G1/G2 facilitated an accurate species classification of Leptospira reference strains. Next, we combined an unsupervised high resolution melting (HRM) method with a new statistical approach using primers to amplify a two variable-number tandem-repeat (VNTR) for typing at the subspecies level. The HRM analysis, which was performed with ScreenClust Software, enabled the identification of genotypes at the serovar level with high resolution power (Hunter-Gaston index 0.984). This method was also applied to Leptospira DNA from blood samples that were obtained from Reunion Island after 1998. We were able to identify a unique genotype that is identical to that of the L. interrogans serovars Copenhageni and Icterohaemorrhagiae, suggesting that this genotype is the major cause of leptospirosis on Reunion Island. Conclusions Our simple, rapid, and robust genotyping method enables the identification of Leptospira strains at the species and subspecies levels and supports the direct genotyping of Leptospira in biological samples without requiring cultures. PMID:26154161

  17. Distribution and dynamics of risk factors associated with highly pathogenic avian influenza H5N1

    PubMed Central

    Zhang, L.; Guo, Z. W.; Bridge, E. S.; Li, Y. M.; Xiao, X. M.

    2016-01-01

    SUMMARY Within China’s Poyang Lake region, close interactions between wild migratory birds and domestic poultry are common and provide an opportunity for the transmission and subsequent outbreaks of highly pathogenic avian influenza (HPAI) virus. We overlaid a series of ecological factors associated with HPAI to map the risk of HPAI in relation to natural and anthropogenic variables, and we identified two hotspots for potential HPAI outbreaks in the Poyang Lake region as well as three corridors connecting the two hotspot areas. In hotspot I, there is potential for migratory birds to bring new avian influenza (AI) strains that can reassort with existing strains to form new AI viruses. Hotspot II features high-density poultry production where outbreaks of endemic AI viruses are likely. The three communication corridors that link the two hotspots further promote HPAI H5N1 transmission and outbreaks and lead to the persistence of AI viruses in the Poyang Lake region. We speculate that the region’s unevenly distributed poultry supply-and-demand system might be a key factor inducing HPAI H5N1 transmission and outbreaks in the Poyang Lake region. PMID:23398949

  18. Survey for Highly Pathogenic Avian Influenza from Poultry in Two Northeastern States, Nigeria

    PubMed Central

    Musa, Ibrahim Waziri; Abdu, Paul Ayuba; Sackey, Anthony Kojo Bedu; Oladele, Sunday Blessing

    2013-01-01

    Highly pathogenic avian influenza (HPAI) is a major global zoonosis. It has a complex ecological distribution with almost unpredictable epidemiological features thus placing it topmost in the World Organization for Animal Health list A poultry diseases. Structured questionnaire survey of poultry farmer's knowledge, attitudes, and practices (KAP) in two Nigerian states revealed the presence of risk farming practices that may enable avian influenza high chance of introduction/reintroduction. There existed significant statistical association between farmer's educational levels and AI awareness and zoonotic awareness (P < 0.005). Poultry rearing of multiage and species (81%), multiple sources of stock (62%), inadequate dead-bird disposal (71%), and access to live bird markets (LBMs) (62%) constituted major biosecurity threats in these poultry farming communities. Haemagglutination inhibition (HI) test detected antibodies against H5 avian influenza (AI) in 8 of the 400 sera samples; rapid antigen detection test kit (RADTK) was negative for all the 400 cloaca and trachea swabs. These results and other poultry diseases similar to AI observed in this study could invariably affect avian influenza early detection, reporting, and control. We recommend strong policy initiatives towards poultry farmers' attitudinal change and increasing efforts on awareness of the implications of future HPAI outbreaks in Nigeria. PMID:23936731

  19. Distribution and dynamics of risk factors associated with highly pathogenic avian influenza H5N1.

    PubMed

    Zhang, L; Guo, Z W; Bridge, E S; Li, Y M; Xiao, X M

    2013-11-01

    Within China's Poyang Lake region, close interactions between wild migratory birds and domestic poultry are common and provide an opportunity for the transmission and subsequent outbreaks of highly pathogenic avian influenza (HPAI) virus. We overlaid a series of ecological factors associated with HPAI to map the risk of HPAI in relation to natural and anthropogenic variables, and we identified two hotspots for potential HPAI outbreaks in the Poyang Lake region as well as three corridors connecting the two hotspot areas. In hotspot I, there is potential for migratory birds to bring new avian influenza (AI) strains that can reassort with existing strains to form new AI viruses. Hotspot II features high-density poultry production where outbreaks of endemic AI viruses are likely. The three communication corridors that link the two hotspots further promote HPAI H5N1 transmission and outbreaks and lead to the persistence of AI viruses in the Poyang Lake region. We speculate that the region's unevenly distributed poultry supply-and-demand system might be a key factor inducing HPAI H5N1 transmission and outbreaks in the Poyang Lake region. PMID:23398949

  20. Current status and future needs in diagnostics and vaccines for high pathogenicity avian influenza.

    PubMed

    Swayne, D E; Spackman, E

    2013-01-01

    Since 1959, 32 epizootics of high pathogenicity avian influenza (HPAI) have occurred in birds. Rapid detection and accurate identification of HPAI has been critical to controlling such epizootics in poultry. Specific paradigms for the detection and diagnosis of avian influenza virus (AIV) in poultry vary somewhat among different countries and industry compartments depending on specific needs and resources. Importantly, since HPAI and low pathogenicity (LP) AI of the H5 and H7 subtypes are reportable to the World Organization for Animal Health (OIE), diagnostic procedures are implemented for regulatory purposes and are harmonized to some degree. Most current tests are adequate and have been in use for some time, therefore they have been well validated and presently there is no reported new technology that will completely replace the current tests. However, some modifications, updates or additional tests could be beneficial. The element of AIV diagnostics that is most in need of improvement is in determining the hemagglutinin and neuraminidase subtype specificity of antibody to AIV. Most HPAI epizootics have been eradicated using traditional stamping-out programs, but beginning in 1995, five epizootics have added vaccination as an additional, interim control tool. From 2002-2010, >113 billion doses of AI vaccine have been used in poultry; 95.5% as oil-emulsified, inactivated whole AIV vaccines and 4.5% as live vectored vaccines. The majority of vaccine has been used in the four H5N1 HPAI enzootic countries (China [91%], Egypt [4.7%], Indonesia [2.3%], and Vietnam [1.4%]) where vaccination programs are directed to all poultry. The 10 other countries/regions have used less than 1% of the vaccine, administered in a focused, risk- based approach. Some vaccine "failures" have resulted from antigenic drift of field viruses away from the vaccine viruses, but most have resulted from failures in the vaccination process; i.e. failure to adequately administer the vaccine to at

  1. Smartphone-Based Fluorescent Diagnostic System for Highly Pathogenic H5N1 Viruses.

    PubMed

    Yeo, Seon-Ju; Choi, Kyunghan; Cuc, Bui Thi; Hong, Nguyen Ngoc; Bao, Duong Tuan; Ngoc, Nguyen Minh; Le, Mai Quynh; Hang, Nguyen Le Khanh; Thach, Nguyen Co; Mallik, Shyam Kumar; Kim, Hak Sung; Chong, Chom-Kyu; Choi, Hak Soo; Sung, Haan Woo; Yu, Kyoungsik; Park, Hyun

    2016-01-01

    Field diagnostic tools for avian influenza (AI) are indispensable for the prevention and controlled management of highly pathogenic AI-related diseases. More accurate, faster and networked on-site monitoring is demanded to detect such AI viruses with high sensitivity as well as to maintain up-to-date information about their geographical transmission. In this work, we assessed the clinical and field-level performance of a smartphone-based fluorescent diagnostic device with an efficient reflective light collection module using a coumarin-derived dendrimer-based fluorescent lateral flow immunoassay. By application of an optimized bioconjugate, a smartphone-based diagnostic device had a two-fold higher detectability as compared to that of the table-top fluorescence strip reader for three different AI subtypes (H5N3, H7N1, and H9N2). Additionally, in a clinical study of H5N1-confirmed patients, the smartphone-based diagnostic device showed a sensitivity of 96.55% (28/29) [95% confidence interval (CI): 82.24 to 99.91] and a specificity of 98.55% (68/69) (95% CI: 92.19 to 99.96). The measurement results from the distributed individual smartphones were wirelessly transmitted via short messaging service and collected by a centralized database system for further information processing and data mining. Smartphone-based diagnosis provided highly sensitive measurement results for H5N1 detection within 15 minutes. Because of its high sensitivity, portability and automatic reporting feature, the proposed device will enable agile identification of patients and efficient control of AI dissemination. PMID:26877781

  2. Smartphone-Based Fluorescent Diagnostic System for Highly Pathogenic H5N1 Viruses

    PubMed Central

    Yeo, Seon-Ju; Choi, Kyunghan; Cuc, Bui Thi; Hong, Nguyen Ngoc; Bao, Duong Tuan; Ngoc, Nguyen Minh; Le, Mai Quynh; Hang, Nguyen Le Khanh; Thach, Nguyen Co; Mallik, Shyam Kumar; Kim, Hak Sung; Chong, Chom-Kyu; Choi, Hak Soo; Sung, Haan Woo; Yu, Kyoungsik; Park, Hyun

    2016-01-01

    Field diagnostic tools for avian influenza (AI) are indispensable for the prevention and controlled management of highly pathogenic AI-related diseases. More accurate, faster and networked on-site monitoring is demanded to detect such AI viruses with high sensitivity as well as to maintain up-to-date information about their geographical transmission. In this work, we assessed the clinical and field-level performance of a smartphone-based fluorescent diagnostic device with an efficient reflective light collection module using a coumarin-derived dendrimer-based fluorescent lateral flow immunoassay. By application of an optimized bioconjugate, a smartphone-based diagnostic device had a two-fold higher detectability as compared to that of the table-top fluorescence strip reader for three different AI subtypes (H5N3, H7N1, and H9N2). Additionally, in a clinical study of H5N1-confirmed patients, the smartphone-based diagnostic device showed a sensitivity of 96.55% (28/29) [95% confidence interval (CI): 82.24 to 99.91] and a specificity of 98.55% (68/69) (95% CI: 92.19 to 99.96). The measurement results from the distributed individual smartphones were wirelessly transmitted via short messaging service and collected by a centralized database system for further information processing and data mining. Smartphone-based diagnosis provided highly sensitive measurement results for H5N1 detection within 15 minutes. Because of its high sensitivity, portability and automatic reporting feature, the proposed device will enable agile identification of patients and efficient control of AI dissemination. PMID:26877781

  3. Atmospheric Temperature Profile Measurements Using Mobile High Spectral Resolution Lidar

    NASA Astrophysics Data System (ADS)

    Razenkov, Ilya I.; Eloranta, Edwin W.

    2016-06-01

    The High Spectral Resolution Lidar (HSRL) designed at the University of Wisconsin-Madison discriminates between Mie and Rayleigh backscattering [1]. It exploits the Doppler effect caused by thermal motion of molecules, which broadens the spectrum of the transmitted laser light. That allows for absolute calibration of the lidar and measurements of the aerosol volume backscatter coefficient. Two iodine absorption filters with different absorption line widths (a regular iodine vapor filter and Argon buffered iodine filter) allow for atmospheric temperature profile measurements. The sensitivity of the measured signal-to-air temperature ratio is around 0.14%/K. The instrument uses a shared telescope transmitter-receiver design and operates in eyesafe mode (the product of laser average power and telescope aperture equals 0.1 Wm2 at 532 nm).

  4. Encapsulating Mobile Proton Carriers into Structural Defects in Coordination Polymer Crystals: High Anhydrous Proton Conduction and Fuel Cell Application.

    PubMed

    Inukai, Munehiro; Horike, Satoshi; Itakura, Tomoya; Shinozaki, Ryota; Ogiwara, Naoki; Umeyama, Daiki; Nagarkar, Sanjog; Nishiyama, Yusuke; Malon, Michal; Hayashi, Akari; Ohhara, Takashi; Kiyanagi, Ryoji; Kitagawa, Susumu

    2016-07-13

    We describe the encapsulation of mobile proton carriers into defect sites in nonporous coordination polymers (CPs). The proton carriers were encapsulated with high mobility and provided high proton conductivity at 150 °C under anhydrous conditions. The high proton conductivity and nonporous nature of the CP allowed its application as an electrolyte in a fuel cell. The defects and mobile proton carriers were investigated using solid-state NMR, XAFS, XRD, and ICP-AES/EA. On the basis of these analyses, we concluded that the defect sites provide space for mobile uncoordinated H3PO4, H2PO4(-), and H2O. These mobile carriers play a key role in expanding the proton-hopping path and promoting the mobility of protons in the coordination framework, leading to high proton conductivity and fuel cell power generation. PMID:27324658

  5. pCal, a highly unusual Ty1/copia retrotransposon from the pathogenic yeast Candida albicans.

    PubMed Central

    Matthews, G D; Goodwin, T J; Butler, M I; Berryman, T A; Poulter, R T

    1997-01-01

    Retrotransposons are mobile genetic elements. They can transpose via the reverse transcription of mRNA into double-stranded DNA (dsDNA) followed by the insertion of this dsDNA into new sites within the host genome. The unintegrated, linear, dsDNA form of retrotransposons is usually very rare. We report here the isolation of a retrotransposon from Candida albicans which is unusual in this respect. This element, which we have named pCal, was first identified as a distinct band when uncut C. albicans DNA was examined on an agarose gel. Sequence analysis of the cloned element revealed that it is a retrotransposon belonging to the Ty1/copia group. It is estimated that pCal produces 50 to 100 free, linear, dsDNA copies of itself per cell. This is a much higher level of expression than even that of the system in which Ty1 is expressed behind the highly active GAL1 promoter on a high-copy-number plasmid (about 10 copies per cell). Another unusual feature of pCal is that its Pol enzymes are likely to be expressed via the pseudoknot-assisted suppression of an upstream, in-phase stop codon, as has been shown for Moloney murine leukemia virus. PMID:9371461

  6. Using Mobile Communication Technology in High School Education: Motivation, Pressure, and Learning Performance

    ERIC Educational Resources Information Center

    Rau, Pei-Luen Patrick; Gao, Qin; Wu, Li-Mei

    2008-01-01

    Motivation and pressure are considered two factors impacting vocational senior high school student learning. New communication technology, especially mobile communication technology, is supposed to be effective in encouraging interaction between the student and the instructor and improving learning efficiency. Social presence and information…

  7. Crustal dynamics project observing plan for highly mobile systems 1981 - 1986

    NASA Technical Reports Server (NTRS)

    Frey, H.

    1980-01-01

    Measurement of crustal motion in the western United States and other tectonically active regions makes use of fixed, movable and highly mobile satellite laser ranging and very long baseline interferometry systems. Measurement of the rotational dynamics of the Earth as well as regional deformation and plate motion are discussed.

  8. Early Reading Skills and Academic Achievement Trajectories of Students Facing Poverty, Homelessness, and High Residential Mobility

    ERIC Educational Resources Information Center

    Herbers, Janette E.; Cutuli, J. J.; Supkoff, Laura M.; Heistad, David; Chan, Chi-Keung; Hinz, Elizabeth; Masten, Ann S.

    2012-01-01

    This investigation tested the importance of early academic achievement for later achievement trajectories among 18,011 students grouped by level of socioeconomic risk. Students considered to be at highest risk were those who experienced homelessness or high residential mobility (HHM). HHM students were compared with students eligible for free…

  9. Mass spectrometric characterization of a high-field asymmetric waveform ion mobility spectrometer

    NASA Astrophysics Data System (ADS)

    Purves, Randy W.; Guevremont, Roger; Day, Stephen; Pipich, Charles W.; Matyjaszczyk, Matthew S.

    1998-12-01

    Ion mobility spectrometry (IMS) has become an important method for the detection of many compounds because of its high sensitivity and amenability to miniaturization for field-portable monitoring; applications include detection of narcotics, explosives, and chemical warfare agents. High-field asymmetric waveform ion mobility spectrometry (FAIMS) differs from IMS in that the electric fields are applied using a high-frequency periodic asymmetric waveform, rather than a dc voltage. Furthermore, in FAIMS the compounds are separated by the difference in the mobility of ions at high electric field relative to low field, rather than by compound to compound differences in mobility at low electric field (IMS). We report here the first cylindrical-geometry-FAIMS interface with mass spectrometry (FAIMS-MS) and the MS identification of the peaks observed in a FAIMS compensation voltage (CV) spectrum. Using both an electrometer-based-FAIMS (FAIMS-E) and FAIMS-MS, several variables that affect the sensitivity of ion detection were examined for two (polarity reversed) asymmetric waveforms (modes 1 and 2) each of which yields a unique spectrum. An increase in the dispersion voltage (DV) was found to improve the sensitivity and separation observed in the FAIMS CV spectrum. This increase in sensitivity and the unexpected dissimilarity in modes 1 and 2 suggest that atmospheric pressure ion focusing is occurring in the FAIMS analyzer. The sensitivity and peak locations in the CV spectra were affected by temperature, gas flow rates, operating pressure, and analyte concentration.

  10. Material selection for highly mobile space suit gloves based on fabric mechanical properties

    NASA Technical Reports Server (NTRS)

    Main, John A.; Peterson, Steven W.; Strauss, Alvin M.

    1993-01-01

    This paper discusses the factors that control the flexibility of fabric space suit elements by examining a bending model of a pressurized fabric tube. Results from the model are used to evaluate the current direction in highly mobile EVA glove research and suggest that changes are necessary in the glove fabric selection methodology.

  11. VIEW OF HB1 (VAB HIGH BAY) WITH MOBILE LAUNCHER PLATFORM ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    VIEW OF HB-1 (VAB HIGH BAY) WITH MOBILE LAUNCHER PLATFORM (VEHICLE ACCESS PLATFORMS ARE VISIBLE IN THE CENTER), FACING WEST - Cape Canaveral Air Force Station, Launch Complex 39, Vehicle Assembly Building, VAB Road, East of Kennedy Parkway North, Cape Canaveral, Brevard County, FL

  12. Integrating mHealth Mobile Applications to Reduce High Risk Drinking among Underage Students

    ERIC Educational Resources Information Center

    Kazemi, Donna M.; Cochran, Allyson R.; Kelly, John F.; Cornelius, Judith B.; Belk, Catherine

    2014-01-01

    Objective: College students embrace mobile cell phones (MCPs) as a primary communication and entertainment device. The aim of this study was to investigate college students' perceptions toward using mHealth technology to deliver interventions to prevent high-risk drinking and associated consequences. Design/setting: Four focus group…

  13. Provision of High-Quality Orientation and Mobility Services to Older Persons with Visual Impairments.

    ERIC Educational Resources Information Center

    Hill, M.-M.

    1991-01-01

    The provision of high quality orientation and mobility (O&M) services to older persons with visual impairments requires consideration of problems in attitudes, client characteristics, financial resources, inservice training, and the availability of age-appropriate assessment instruments. This paper discusses research on O&M interventions and…

  14. Considering the Geographic Dispersion of Homeless and Highly Mobile Students and Families

    ERIC Educational Resources Information Center

    Miller, Peter M.; Bourgeois, Alexis K.

    2013-01-01

    This article addresses school and community-level issues associated with the expanding crisis of student homelessness in the United States. We note that while an increased geographic dispersion of homeless and highly mobile (HHM) families is largely attributed to the widespread effects of the economic recession, it is also furthered by shifting…

  15. Characterization of a novel highly pathogenic H5N2 avian influenza virus isolated from a duck in eastern China.

    PubMed

    Wu, Haibo; Peng, Xiaorong; Xu, Lihua; Jin, Changzhong; Cheng, Linfang; Lu, Xiangyun; Xie, Tiansheng; Yao, Hangping; Wu, Nanping

    2014-12-01

    During surveillance for avian influenza viruses (AIVs) in live-poultry markets (LPMs) in eastern China in 2013, one H5N2 AIV was isolated from a duck. Phylogenetic analysis showed that the hemagglutinin of this strain belongs to clade 2.3.4 and received its genes from H5, H3 and H6 AIVs of poultry in China. The virulence of this strain was examined in chickens and mice, and it was found to be highly pathogenic in chickens but demonstrated moderate pathogenicity in mice. These results suggest that active surveillance of AIVs in LPMs should be used in an early warning system for avian influenza outbreaks. PMID:25091744

  16. Emergence of H5N1 high pathogenicity avian influenza strains in Indonesia that are resistant to vaccines

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Vaccines have been used to protect poultry in Asia against H5N1 high pathogenicity avian influenza (HPAI) since 2002. Reports of vaccine “failures” began to emerge in 2006 in Indonesia, with identification of clinical disease consistent with HPAI or isolation of H5N1 HPAIV in vaccinated flocks or in...

  17. What are the possible transmission methods for H5N1 high pathogenicity avian influenza viruses to people

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The H5N1 high pathogenicity avian influenza (HPAI) virus has caused an unprecedented epizootic affecting poultry in Asia, Africa and parts of Europe, but has crossed multiple species barriers to infect captive and wild birds, carnivorous mammals and humans. Human infections (391 infections with 247...

  18. Highly Pathogenic Avian Influenza Virus (H5N1) Outbreak in Captive Wild Birds and Cats, Cambodia

    PubMed Central

    Marx, Nick; Ong, Sivuth; Gaidet, Nicolas; Hunt, Matt; Manuguerra, Jean-Claude; Sorn, San; Peiris, Malik; Van der Werf, Sylvie; Reynes, Jean-Marc

    2009-01-01

    From December 2003 through January 2004, the Phnom Tamao Wildlife Rescue Centre, Cambodia, was affected by the highly pathogenic influenza virus (H5N1). Birds from 26 species died. Influenza virus subtype H5N1 was detected in 6 of 7 species tested. Cats from 5 of 7 species were probably infected; none died. PMID:19239769

  19. Bronchointerstitial pneumonia in guinea pigs following inoculation with H5N1 high pathogenicity avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The H5N1 high pathogenicity avian influenza (HPAI) viruses have caused widespread disease of poultry in Asia, Africa and the Middle East, and sporadic human infections. The guinea pig model has been used to study human H3N2 and H1N1 influenza viruses, but knowledge is lacking on H5N1 HPAI virus inf...

  20. Mechanisms of transmission and spread of H5N1 high pathogenicity avian influenza virus in birds and mammals

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Eurasian-African H5N1 high pathogenicity avian influenza (HPAI) virus has crossed multiple species barriers to infect poultry, captive and wild birds, carnivorous mammals and humans. The specific transmission mechanisms are unclear in most cases, but experimental studies and field data sug...

  1. Microarray analysis following infection with highly pathogenic avian influenza H5N1 virus in naive and vaccinated SPF chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Avian influenza (AI) is a viral disease of poultry that remains a constant threat to commercial poultry throughout the world. Within the last few years, outbreaks of highly pathogenic avian influenza (HPAI) H5N1 have originated in Southeast Asia and spread to several European, Middle Eastern, and A...

  2. The pathobiology of highly pathogenic H5N2 avian influenza virus in Ruddy ducks and Lesser Scaup

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The susceptibility and pathogenesis of avian influenza virus (AIV) has not been characterized in numerous duck species, especially diving ducks, some of which migrate across the continental U.S. The pathobiology of highly pathogenic (HP) H5N2 AIV was characterized in two diving duck species, Ruddy ...

  3. Early responses of chicken lungs and spleens to infection with highly pathogenic avian influenza virus using microarray analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Within the last few years, outbreaks of highly pathogenic avian influenza (HPAI) have originated in Asia and spread through several Middle Eastern, African and European countries, resulting in one of the most serious animal disease incident in recent history. These outbreaks were characterized by t...

  4. THERMAL INACTIVATION OF H5N1 HIGH PATHOGENICITY AVIAN INFLUENZA VIRUS IN NATURALLY INFECTED CHICKEN MEAT

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thermal inactivation of the H5N1 high pathogenicity avian influenza (HPAI) virus strain A/chicken/Korea/ES/2003 (Korea/03) was quantitatively measured in thigh and breast meat harvested from infected chickens. The average Korea/03 titers in uncooked meat samples were 8.0 log 10 EID50/g (thigh) and 7...

  5. Inhibition of enteric pathogens and surrogates using integrated, high intensity 405nm led light on the surface of almonds

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The disinfecting properties of 405 nm light were investigated against Escherichia coli O157:H7, Salmonella, and their non-pathogenic surrogate bacteria on the surface of almonds. High intensity monochromatic blue light (MBL) was generated from an array of narrow-band 405 nm light-emitting diodes (LE...

  6. Efficacy of commercial vaccines in chickens and ducks against H5N1 highly pathogenic avian influenza viruses from Vietnam

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Highly pathogenic (HP) H5N1 avian influenza (AI) viruses continue to circulate in Asia and have spread to other regions of the world. Though attempts at eradication of the viruses during various outbreaks have been successful for short periods of time, new strains of H5N1 viruses continue to emerge...

  7. 75 FR 17368 - Notice of Availability of an Evaluation of the Highly Pathogenic Avian Influenza Status of Czech...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-06

    ... additional risk factors that would indicate that domestic poultry in the Czech Republic and Sweden continue... introduction of diseases and pests into the U.S. livestock and poultry populations. Highly pathogenic avian influenza (HPAI) is a zoonotic disease of poultry. The H5N1 subtype of HPAI is an extremely infectious...

  8. Widespread detection of highly pathogenic H5 influenza viruses in wild birds from the Pacific Flyway of the United States

    USGS Publications Warehouse

    Bevins, S.N.; Dusek, Robert J.; White, C. LeAnn; Gidlewski, Thomas; Bodenstein, B.; Mansfield, Kristin G.; DeBruyn, Paul; Kraege, Donald K.; Rowan, E.L.; Gillin, Colin; Thomas, B.; Chandler, S.; Baroch, J.; Schmit, B.; Grady, M. J.; Miller, R. S.; Drew, M.L.; Stopak, S.; Zscheile, B.; Bennett, J.; Sengl, J.; Brady, Caroline; Ip, Hon S.; Spackman, Erica; Killian, M. L.; Torchetti, Mia Kim; Sleeman, Jonathan M.; DeLiberto, T.J.

    2016-01-01

    A novel highly pathogenic avian influenza virus belonging to the H5 clade 2.3.4.4 variant viruses was detected in North America in late 2014. Motivated by the identification of these viruses in domestic poultry in Canada, an intensive study was initiated to conduct highly pathogenic avian influenza surveillance in wild birds in the Pacific Flyway of the United States. A total of 4,729 hunter-harvested wild birds were sampled and highly pathogenic avian influenza virus was detected in 1.3% (n = 63). Three H5 clade 2.3.4.4 subtypes were isolated from wild birds, H5N2, H5N8, and H5N1, representing the wholly Eurasian lineage H5N8 and two novel reassortant viruses. Testing of 150 additional wild birds during avian morbidity and mortality investigations in Washington yielded 10 (6.7%) additional highly pathogenic avian influenza isolates (H5N8 = 3 and H5N2 = 7). The geographically widespread detection of these viruses in apparently healthy wild waterfowl suggest that the H5 clade 2.3.4.4 variant viruses may behave similarly in this taxonomic group whereby many waterfowl species are susceptible to infection but do not demonstrate obvious clinical disease. Despite these findings in wild waterfowl, mortality has been documented for some wild bird species and losses in US domestic poultry during the first half of 2015 were unprecedented.

  9. Surveillance for Highly Pathogenic Avian Influenza Virus in Wild Birds during Outbreaks in Domestic Poultry, Minnesota, 2015.

    PubMed

    Jennelle, Christopher S; Carstensen, Michelle; Hildebrand, Erik C; Cornicelli, Louis; Wolf, Paul; Grear, Daniel A; Ip, Hon S; Vandalen, Kaci K; Minicucci, Larissa A

    2016-07-01

    In 2015, a major outbreak of highly pathogenic avian influenza virus (HPAIV) infection devastated poultry facilities in Minnesota, USA. To understand the potential role of wild birds, we tested 3,139 waterfowl fecal samples and 104 sick and dead birds during March 9-June 4, 2015. HPAIV was isolated from a Cooper's hawk but not from waterfowl fecal samples. PMID:27064759

  10. Surveillance for highly pathogenic avian influenza virus in wild birds during outbreaks in domestic poultry, Minnesota, 2015

    USGS Publications Warehouse

    Jennelle, Christopher S.; Carstensen, Michelle; Hildebrand, Erik C.; Cornicelli, Louis; Wolf, Paul C.; Grear, Daniel; Ip, Hon S.; VanDalen, Kaci K.; Minicucci, Larissa A.

    2016-01-01

    In 2015, a major outbreak of highly pathogenic avian influenza virus (HPAIV) infection devastated poultry facilities in Minnesota, USA. To clarify the role of wild birds, we tested 3,139 waterfowl fecal samples and 104 sick and dead birds during March 9–June 4, 2015. HPAIV was isolated from a Cooper’s hawk but not from waterfowl.

  11. Widespread detection of highly pathogenic H5 influenza viruses in wild birds from the Pacific Flyway of the United States

    PubMed Central

    Bevins, S. N.; Dusek, R. J.; White, C. L.; Gidlewski, T.; Bodenstein, B.; Mansfield, K. G.; DeBruyn, P.; Kraege, D.; Rowan, E.; Gillin, C.; Thomas, B.; Chandler, S.; Baroch, J.; Schmit, B.; Grady, M. J.; Miller, R. S.; Drew, M. L.; Stopak, S.; Zscheile, B.; Bennett, J.; Sengl, J.; Brady, Caroline; Ip, H. S.; Spackman, E.; Killian, M. L.; Torchetti, M. K.; Sleeman, J. M.; Deliberto, T. J.

    2016-01-01

    A novel highly pathogenic avian influenza virus belonging to the H5 clade 2.3.4.4 variant viruses was detected in North America in late 2014. Motivated by the identification of these viruses in domestic poultry in Canada, an intensive study was initiated to conduct highly pathogenic avian influenza surveillance in wild birds in the Pacific Flyway of the United States. A total of 4,729 hunter-harvested wild birds were sampled and highly pathogenic avian influenza virus was detected in 1.3% (n = 63). Three H5 clade 2.3.4.4 subtypes were isolated from wild birds, H5N2, H5N8, and H5N1, representing the wholly Eurasian lineage H5N8 and two novel reassortant viruses. Testing of 150 additional wild birds during avian morbidity and mortality investigations in Washington yielded 10 (6.7%) additional highly pathogenic avian influenza isolates (H5N8 = 3 and H5N2 = 7). The geographically widespread detection of these viruses in apparently healthy wild waterfowl suggest that the H5 clade 2.3.4.4 variant viruses may behave similarly in this taxonomic group whereby many waterfowl species are susceptible to infection but do not demonstrate obvious clinical disease. Despite these findings in wild waterfowl, mortality has been documented for some wild bird species and losses in US domestic poultry during the first half of 2015 were unprecedented. PMID:27381241

  12. Outbreaks of highly pathogenic Eurasian H5N8 avian influenza in two commercial poultry flocks in California

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In January 2015, a highly pathogenic Eurasian lineage H5N8 avian influenza (AI) virus was detected in a commercial meat turkey flock in Stanislaus County, California. Approximately 3 weeks later, a similar case was diagnosed in commercial chickens from a different company located in Kings County, C...

  13. NS1 gene truncations partially attenuate H5N1 highly pathogenic avian influenza viruses in chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The polybasic amino acid sequence in the hemagglutinin (HA) protein of H5 and H7 avian influenza (AI) viruses determines the high pathogenicity (HP) phenotype in chickens. The NS1 protein plays an important role in blocking the induction of antiviral defenses and other regulatory functions and thus...

  14. Susceptibility of selected wild avian species to experimental infection with H5N1 high pathogenicity avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Since 2002, H5N1 highly pathogenic avian influenza (HPAI) viruses have caused mortality in wide diversity of wild avian species but, to date, the role that different species play in the transmission and maintenance of H5N1 HPAI viruses is poorly understood. To begin to address these uncertainties a...

  15. Widespread detection of highly pathogenic H5 influenza viruses in wild birds from the Pacific Flyway of the United States.

    PubMed

    Bevins, S N; Dusek, R J; White, C L; Gidlewski, T; Bodenstein, B; Mansfield, K G; DeBruyn, P; Kraege, D; Rowan, E; Gillin, C; Thomas, B; Chandler, S; Baroch, J; Schmit, B; Grady, M J; Miller, R S; Drew, M L; Stopak, S; Zscheile, B; Bennett, J; Sengl, J; Brady, Caroline; Ip, H S; Spackman, E; Killian, M L; Torchetti, M K; Sleeman, J M; Deliberto, T J

    2016-01-01

    A novel highly pathogenic avian influenza virus belonging to the H5 clade 2.3.4.4 variant viruses was detected in North America in late 2014. Motivated by the identification of these viruses in domestic poultry in Canada, an intensive study was initiated to conduct highly pathogenic avian influenza surveillance in wild birds in the Pacific Flyway of the United States. A total of 4,729 hunter-harvested wild birds were sampled and highly pathogenic avian influenza virus was detected in 1.3% (n = 63). Three H5 clade 2.3.4.4 subtypes were isolated from wild birds, H5N2, H5N8, and H5N1, representing the wholly Eurasian lineage H5N8 and two novel reassortant viruses. Testing of 150 additional wild birds during avian morbidity and mortality investigations in Washington yielded 10 (6.7%) additional highly pathogenic avian influenza isolates (H5N8 = 3 and H5N2 = 7). The geographically widespread detection of these viruses in apparently healthy wild waterfowl suggest that the H5 clade 2.3.4.4 variant viruses may behave similarly in this taxonomic group whereby many waterfowl species are susceptible to infection but do not demonstrate obvious clinical disease. Despite these findings in wild waterfowl, mortality has been documented for some wild bird species and losses in US domestic poultry during the first half of 2015 were unprecedented. PMID:27381241

  16. The vOTU domain of highly-pathogenic porcine reproductive and respiratory syndrome virus displays a differential substrate preference

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Arterivirus genus member Porcine reproductive and respiratory syndrome virus (PRRSV) causes an economically devastating disease that presents global concerns to the pork industry, which have been exacerbated by the emergence of a highly pathogenic PRRSV strain (HP-PRRSV) in China and Southeast Asia....

  17. Lab-on-a-chip modules for detection of highly pathogenic bacteria: from sample preparation to detection

    NASA Astrophysics Data System (ADS)

    Julich, S.; Kopinč, R.; Hlawatsch, N.; Moche, C.; Lapanje, A.; Gärtner, C.; Tomaso, H.

    2014-05-01

    Lab-on-a-chip systems are innovative tools for the detection and identification of microbial pathogens in human and veterinary medicine. The major advantages are small sample volume and a compact design. Several fluidic modules have been developed to transform analytical procedures into miniaturized scale including sampling, sample preparation, target enrichment, and detection procedures. We present evaluation data for single modules that will be integrated in a chip system for the detection of pathogens. A microfluidic chip for purification of nucleic acids was established for cell lysis using magnetic beads. This assay was evaluated with spiked environmental aerosol and swab samples. Bacillus thuringiensis was used as simulant for Bacillus anthracis, which is closely related but non-pathogenic for humans. Stationary PCR and a flow-through PCR chip module were investigated for specific detection of six highly pathogenic bacteria. The conventional PCR assays could be transferred into miniaturized scale using the same temperature/time profile. We could demonstrate that the microfluidic chip modules are suitable for the respective purposes and are promising tools for the detection of bacterial pathogens. Future developments will focus on the integration of these separate modules to an entire lab-on-a-chip system.

  18. Microsatellite markers for Sclerotinia subarctica nom. prov., a new vegetable pathogen of the High North

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Eight polymorphic microsatellite loci were isolated from the ascomycete fungus Sclerotinia subarctica nom. prov. In Alaska, this pathogen causes white mold vegetable diseases sympatrically with the cosmopolitan and closely related Sclerotinia sclerotiorum. Eighteen alleles were observed across the 4...

  19. Using Extreme Value Theory Approaches to Forecast the Probability of Outbreak of Highly Pathogenic Influenza in Zhejiang, China

    PubMed Central

    Chen, Jiangpeng; Lei, Xun; Zhang, Li; Peng, Bin

    2015-01-01

    Background Influenza is a contagious disease with high transmissibility to spread around the world with considerable morbidity and mortality and presents an enormous burden on worldwide public health. Few mathematical models can be used because influenza incidence data are generally not normally distributed. We developed a mathematical model using Extreme Value Theory (EVT) to forecast the probability of outbreak of highly pathogenic influenza. Methods The incidence data of highly pathogenic influenza in Zhejiang province from April 2009 to November 2013 were retrieved from the website of Health and Family Planning Commission of Zhejiang Province. MATLAB “VIEM” toolbox was used to analyze data and modelling. In the present work, we used the Peak Over Threshold (POT) model, assuming the frequency as a Poisson process and the intensity to be Pareto distributed, to characterize the temporal variability of the long-term extreme incidence of highly pathogenic influenza in Zhejiang, China. Results The skewness and kurtosis of the incidence of highly pathogenic influenza in Zhejiang between April 2009 and November 2013 were 4.49 and 21.12, which indicated a “fat tail” distribution. A QQ plot and a mean excess plot were used to further validate the features of the distribution. After determining the threshold, we modeled the extremes and estimated the shape parameter and scale parameter by the maximum likelihood method. The results showed that months in which the incidence of highly pathogenic influenza is about 4462/2286/1311/487 are predicted to occur once every five/three/two/one year, respectively. Conclusions Despite the simplicity, the present study successfully offers the sound modeling strategy and a methodological avenue to implement forecasting of an epidemic in the midst of its course. PMID:25710503

  20. Cockroaches as a Source of High Bacterial Pathogens with Multidrug Resistant Strains in Gondar Town, Ethiopia

    PubMed Central

    Huruy, Kahsay; Muluye, Dagnachew; Feleke, Tigist; G/Silassie, Fisha; Ayalew, Getenet; Nagappan, Raja

    2016-01-01

    Background. Cockroaches are source of bacterial infections and this study was aimed to assess bacterial isolates and their antimicrobial profiles from cockroaches in Gondar town, Ethiopia. Methods. A total of 60 cockroaches were collected from March 1 to May 30, 2014, in Gondar town. Bacterial species were isolated from external and internal parts of cockroaches. Disk diffusion method was used to determine antibiotic susceptibility patterns. Data were entered and analyzed by using SPSS version 20; P values <0.005 were considered as statistically significant. Results. Of 181 identified bacteria species, 110 (60.8%) and 71 (39.2%) were identified from external and internal parts of cockroaches, respectively. Klebsiella pneumoniae 32 (17.7%), Escherichia coli 29 (16%), and Citrobacter spp. 27 (15%) were the predominant isolates. High resistance rate was observed to cotrimoxazole, 60 (33.1%), and least resistance rate was noted to ciprofloxacin, 2 (1.1%). Additionally, 116 (64.1%) of the isolates were MDR strains; Salmonella spp. were the leading MDR isolates (100%) followed by Enterobacter (90.5%) and Shigella spp. (76.9%). Conclusion. Cockroaches are the potential source of bacteria pathogens with multidrug resistant strains and hence effective preventive and control measures are required to minimize cockroach related infections. PMID:27340653

  1. The avian and mammalian host range of highly pathogenic avian H5N1 influenza

    PubMed Central

    Kaplan, Bryan S.; Webby, Richard J.

    2013-01-01

    Highly pathogenic H5N1 influenza viruses have been isolated from a number of avian and mammalian species. Despite intensive control measures the number of human and animal cases continues to increase. A more complete understanding of susceptible species and of contributing environmental and molecular factors is crucial if we are to slow the rate of new cases. H5N1 is currently endemic in domestic poultry in only a handful of countries with sporadic and unpredictable spread to other countries. Close contact of terrestrial bird or mammalian species with infected poultry/waterfowl or their biological products is the major route for interspecies transmission. Intra-species transmission of H5N1 in mammals, including humans, has taken place on a limited scale though it remains to be seen if this will change; recent laboratory studies suggest that it is indeed possible. Here we review the avian and mammalian species that are naturally susceptible to H5N1 infection and the molecular factors associated with its expanded host range. PMID:24025480

  2. New Reassortant H5N6 Highly Pathogenic Avian Influenza Viruses in Southern China, 2014.

    PubMed

    Jiao, Peirong; Cui, Jin; Song, Yafen; Song, Hui; Zhao, Zhishan; Wu, Siyu; Qu, Nannan; Wang, Nianchen; Ouyang, Guowen; Liao, Ming

    2016-01-01

    New reassortant H5N6 highly pathogenic avian influenza viruses (AIVs) were isolated from apparently healthy domestic ducks in Southern China in 2014. Our results show that the viruses grew efficiently in eggs and replicated systemically in chickens. They were completely lethal in chicken (100% mortality), and the mean death time was 6 to 7 days post-inoculation. The viruses could transmit in chickens by naïve contact. BLAST analysis revealed that their HA gene was most closely related to A/wild duck/Shangdong/628/2011 (H5N1), and their NA genes were most closely related to A/swine/Guangdong/K6/2010 (H6N6). The other genes had the highest identity with A/wild duck/Fujian/1/2011(H5N1). The results of phylogenetic analysis showed that their HA genes clustered into clade 2.3.4.4 of the H5N1 viruses and all genes derived from H5 were Mix-like or H6-like viruses. Thus, the new H5N6 viruses were reassortmented of H5N1 and H6N6 virus. Therefore, the circulation of the new H5N6 AIVs may become a threat to poultry and human health. PMID:27242767

  3. Immune responses in piglets infected with highly pathogenic porcine reproductive and respiratory syndrome virus.

    PubMed

    Wang, Gang; Song, Tengfei; Yu, Ying; Liu, Yonggang; Shi, Wenda; Wang, Shujie; Rong, Fulong; Dong, Jianguo; Liu, He; Cai, Xuehui; Zhou, En-Min

    2011-08-15

    Porcine reproductive and respiratory syndrome virus (PRRSV) infection compromises the host's innate and adaptive immunity. The aim of this study was to investigate the immune responses of piglets infected with highly pathogenic (HP) PRRSV (HuN4 strain) with or without the immunization with CH-1R attenuated PRRSV vaccine. The response was evaluated for the clinical signs, pathological changes and virus load in immune organs, antibody responses and levels of serum IFN-γ, IL-4 and IL-10. The result showed that in comparison with the piglets received the immunization, the piglets infected with HP-PRRSV alone had the thymus atrophy, decreased serum levels of IL-4 and increased serum levels of IL-10 and INF-γ. These results suggest that elevated IL-10 levels at the early stage of the infection may enhance virus survival and delay the induction of protective immunity, while increased levels of IL-4 induce the effective immune responses and increase the animals' health status. PMID:21612828

  4. Livestock agroterrorism: the deliberate introduction of a highly infectious animal pathogen.

    PubMed

    Yeh, Jung-Yong; Seo, Hyun-Ji; Park, Jee-Yong; Cho, Yun Sang; Cho, In-Soo; Lee, Ji-Hye; Hwang, Jeong-Min; Choi, In-Soo

    2012-10-01

    Agroterrorism refers to attacks with any of a variety of biological or chemical agents against commercial crops or livestock populations, either as targets in their own right or as vehicles to attack humans. An agroterrorism incident would generally involve bioterrorism, and potential agents include pathogens such as viruses, bacteria, or fungi. Within the context of agroterrorism, livestock agroterrorism is described as the intentional introduction of an animal-borne infectious disease with the goal of spreading fear, producing economic losses, and/or threatening social stability. Causing human illness or human casualties is another potential goal of livestock agroterrorism. Livestock agroterrorism is considered to be attractive to terrorists because biological agents that affect livestock or poultry are more readily available and more difficult to monitor than are agents that infect humans. In addition, a terrorist attack on animal husbandry may have huge economic consequences with no human casualties. Therefore, a biological attack that targets the animal husbandry sector should be regarded as both a "high-consequence" event and a grave national security risk. This review addresses the use of biological weapons that may be used to target livestock or poultry rather than agricultural inputs or equipment. It first defines livestock agroterrorism. Then, the common priority disease agents that may be used to target livestock or poultry in an agroterrorist attack and that are attractive to terrorists are outlined. PMID:23035724

  5. Risk factors and clusters of Highly Pathogenic Avian Influenza H5N1 outbreaks in Bangladesh

    PubMed Central

    Loth, Leo; Gilbert, Marius; Osmani, Mozaffar G.; Kalam, Abul M.; Xiao, Xiangming

    2016-01-01

    Between March 2007 and July 2009, 325 Highly Pathogenic Avian Influenza (HPAI, subtype H5N1) outbreaks in poultry were reported in 154 out of a total of 486 sub-districts in Bangladesh. This study analyzed the temporal and spatial patterns of HPAI H5N1 outbreaks and quantified the relationship between several spatial risk factors and HPAI outbreaks in sub-districts in Bangladesh. We assessed spatial autocorrelation and spatial dependence, and identified clustering sub-districts with disease statistically similar to or dissimilar from their neighbors. Three significant risk factors associated to HPAI H5N1 virus outbreaks were identified; the quadratic log-transformation of human population density [humans per square kilometer, P = 0.01, OR 1.15 (95% CI: 1.03–1.28)], the log-transformation of the total commercial poultry population [number of commercial poultry per sub-district, P < 0.002, OR 1.40 (95% CI: 1.12–1.74)], and the number of roads per sub-district [P = 0.02, OR 1.07 (95% CI: 1.01–1.14)]. The distinct clusters of HPAI outbreaks and risk factors identified could assist the Government of Bangladesh to target surveillance and to concentrate response efforts in areas where disease is likely to occur. Concentrating response efforts may help to combat HPAI more effectively, reducing the environmental viral load and so reducing the number of disease incidents. PMID:20554337

  6. Extent of antigenic cross-reactivity among highly pathogenic H5N1 influenza viruses.

    PubMed

    Ducatez, Mariette F; Cai, Zhipeng; Peiris, Malik; Guan, Yi; Ye, Zhiping; Wan, Xiu-Feng; Webby, Richard J

    2011-10-01

    Highly pathogenic H5N1 avian influenza viruses emerged in 1996 and have since evolved so extensively that a single strain can no longer be used as a prepandemic vaccine or diagnostic reagent. We therefore sought to identify the H5N1 strains that may best serve as cross-reactive diagnostic reagents. We compared the cross-reactivity of 27 viruses of clades 0, 1, 2.1, 2.2, 2.3, and 4 and of four computationally designed ancestral H5N1 strains by hemagglutination inhibition (HI) and microneutralization (MN) assays. Antigenic cartography was used to analyze the large quantity of resulting data. Cartographs of HI titers with chicken red blood cells were similar to those of MN titers, but HI with horse red blood cells decreased antigenic distances among the H5N1 strains studied. Thus, HI with horse red blood cells seems to be the assay of choice for H5N1 diagnostics. Whereas clade 2.2 antigens were able to detect antibodies raised to most of the tested H5N1 viruses (and clade 2.2-specific antisera detected most of the H5N1 antigens), ancestral strain A exhibited the widest reactivity pattern and hence was the best candidate diagnostic reagent for broad detection of H5N1 strains. PMID:21832017

  7. New reassortant H5N8 highly pathogenic avian influenza virus from waterfowl in Southern China

    PubMed Central

    Song, Yafen; Cui, Jin; Song, Hui; Ye, Jiaqi; Zhao, Zhishan; Wu, Siyu; Xu, Chenggang; Jiao, Peirong; Liao, Ming

    2015-01-01

    New reassortant H5N8 highly pathogenic avian influenza viruses were isolated from waterfowl in Southern China. Blast analysis demonstrated that the PB2 gene in these viruses were most closely related to A/wild duck/Shangdong/628/2011 (H5N1), while their NP genes were both more closely related to A/wild duck/Shandong/1/2011 (H5N1) and A/duck/Jiangsu/k1203/2010 (H5N8). However, the HA, NA, PB1, PA, M, and NS genes had the highest identity with A/duck/Jiangsu/k1203/2010 (H5N8). Phylogenetic analysis revealed that their HA genes belonged to the same GsGd H5 clade 2.3.4.4 detected in China in 2010. Therefore, we supposed that these H5N8 viruses might be novel reassortant viruses that have a H5N8 backbone while acquiring PB2 and NP genes from H5N1 viruses. This study is useful for better understanding the genetic and antigenic evolution of H5 avian influenza viruses in Southern China. PMID:26557113

  8. Cockroaches as a Source of High Bacterial Pathogens with Multidrug Resistant Strains in Gondar Town, Ethiopia.

    PubMed

    Moges, Feleke; Eshetie, Setegn; Endris, Mengistu; Huruy, Kahsay; Muluye, Dagnachew; Feleke, Tigist; G/Silassie, Fisha; Ayalew, Getenet; Nagappan, Raja

    2016-01-01

    Background. Cockroaches are source of bacterial infections and this study was aimed to assess bacterial isolates and their antimicrobial profiles from cockroaches in Gondar town, Ethiopia. Methods. A total of 60 cockroaches were collected from March 1 to May 30, 2014, in Gondar town. Bacterial species were isolated from external and internal parts of cockroaches. Disk diffusion method was used to determine antibiotic susceptibility patterns. Data were entered and analyzed by using SPSS version 20; P values <0.005 were considered as statistically significant. Results. Of 181 identified bacteria species, 110 (60.8%) and 71 (39.2%) were identified from external and internal parts of cockroaches, respectively. Klebsiella pneumoniae 32 (17.7%), Escherichia coli 29 (16%), and Citrobacter spp. 27 (15%) were the predominant isolates. High resistance rate was observed to cotrimoxazole, 60 (33.1%), and least resistance rate was noted to ciprofloxacin, 2 (1.1%). Additionally, 116 (64.1%) of the isolates were MDR strains; Salmonella spp. were the leading MDR isolates (100%) followed by Enterobacter (90.5%) and Shigella spp. (76.9%). Conclusion. Cockroaches are the potential source of bacteria pathogens with multidrug resistant strains and hence effective preventive and control measures are required to minimize cockroach related infections. PMID:27340653

  9. Egg-independent vaccine strategies for highly pathogenic H5N1 influenza viruses.

    PubMed

    Pandey, Aseem; Singh, Neetu; Sambhara, Suryaprakash; Mittal, Suresh K

    2010-02-01

    The emergence of a highly pathogenic H5N1 influenza virus in Hong Kong in 1997 and the subsequent appearance of other H5N1 strains and their spread to several countries in southeast Asia, Africa, the Middle East and Europe has evoked fear of a global influenza pandemic. Vaccines offer the best hope to combat the threat of an influenza pandemic. However, the global demand for a pandemic vaccine cannot be fulfilled by the current egg-based vaccine manufacturing strategies, thus creating a need to explore alternative technologies for vaccine production and delivery. Several egg-independent vaccine approaches such as cell culture-derived whole virus or subvirion vaccines, recombinant protein-based vaccines, virus-like particle (VLP) vaccines, DNA vaccines and viral vector-based vaccines are currently being investigated and appear promising both in preclinical and clinical studies. The present review will highlight the various egg-independent alternative vaccine approaches for pandemic influenza. PMID:19875936

  10. Identifying risk factors of highly pathogenic avian influenza (H5N1 subtype) in Indonesia

    PubMed Central

    Leo, Loth; Marius, Gilbert; Jianmei, Wu; Christina, Czarnecki; Muhammad, Hidayat; Xiangming, Xiao

    2016-01-01

    Highly pathogenic avian influenza (HPAI), subtype H5N1, was first officially reported in Indonesia in 2004. Since then the disease has spread and is now endemic in large parts of the country. This study investigated the statistical relationship between a set of risk factors and the presence or absence of HPAI in Indonesia during 2006 and 2007. HPAI was evaluated through participatory disease surveillance (PDS) in backyard village chickens (the study population), and risk factors included descriptors of people and poultry distribution (separating chickens, ducks and production sectors), poultry movement patterns and agro-ecological conditions. The study showed that the risk factors “elevation”, “human population density” and “rice cropping” were significant in accounting for the spatial variation of the PDS-defined HPAI cases. These findings were consistent with earlier studies in Thailand and Vietnam. In addition “commercial poultry population”, and two indicators of market locations and transport; “human settlements” and “road length”, were identified as significant risk factors in the models. In contrast to several previous studies carried out in Southeast Asia, domestic backyard ducks were not found to be a significant risk factor in Indonesia. The study used surrogate estimates of market locations and marketing chains and further work should focus on the actual location of the live bird markets, and on the flow of live poultry and poultry products between them, so that patterns of possible transmission, and regions of particular risk could be better inferred. PMID:21813198

  11. Assessment of the Potential Distance of Dispersal of High Pathogenicity Avian Influenza Virus by Wild Mallards.

    PubMed

    Śmietanka, Krzysztof; Bocian, Łukasz; Meissner, Włodzimierz; Ziętek-Barszcz, Anna; Żółkoś, Katarzyna

    2016-05-01

    This work presents the results of studies aimed at assessing the median and maximum distances covered by wild mallards (Anas platyrhynchos; n = 38), hypothetically infected with the high pathogenicity avian influenza virus (HPAIV) during spring migrations, using GPS-GSM tracking and published data on the susceptibility to HPAIV infection and duration of shedding. The model was based on the assumptions that the birds shed virus in the absence of clinical signs during infectious periods (IP) that were assumed to last 1 day (IP1), 4 days (IP4), and 8 days (IP8) and that each day of migration is a hypothetical day of the onset of IP. Using the haversine formula over a sliding timeframe corresponding to each IP, distances were estimated for each duck that undertook migration and then the maximum distance (Dmax) was selected. Ten mallards undertook spring migrations but, due to the loss of signal in the GPS-GSM devices, only three ducks were observed during autumn migrations. The following ranges of Dmax values were calculated for spring migrations: 124-382 km for IP1 (median 210 km), 208-632 km for IP4 (median 342 km), and 213-687 km for IP8 (median 370 km). The present study provides information that can be used as a data source to perform risk assessment related to the contribution of wild mallards in the dispersal of HPAIV over considerable distances. PMID:27309073

  12. The Transmissibility of Highly Pathogenic Avian Influenza in Commercial Poultry in Industrialised Countries

    PubMed Central

    Garske, Tini; Clarke, Paul; Ghani, Azra C.

    2007-01-01

    Background With the increased occurrence of outbreaks of H5N1 worldwide there is concern that the virus could enter commercial poultry farms with severe economic consequences. Methodology/Principal Findings We analyse data from four recent outbreaks of highly pathogenic avian influenza (HPAI) in commercial poultry to estimate the farm-to-farm reproductive number for HPAI. The reproductive number is a key measure of the transmissibility of HPAI at the farm level because it can be used to evaluate the effectiveness of the control measures. In these outbreaks the mean farm-to-farm reproductive number prior to controls ranged from 1.1 to 2.4, with the maximum farm-based reproductive number in the range 2.2 to 3.2. Enhanced bio-security, movement restrictions and prompt isolation of the infected farms in all four outbreaks substantially reduced the reproductive number, but it remained close to the threshold value 1 necessary to ensure the disease will be eradicated. Conclusions/Significance Our results show that depending on the particular situation in which an outbreak of avian influenza occurs, current controls might not be enough to eradicate the disease, and therefore a close monitoring of the outbreak is required. The method we used for estimating the reproductive number is straightforward to implement and can be used in real-time. It therefore can be a useful tool to inform policy decisions. PMID:17406673

  13. New Reassortant H5N6 Highly Pathogenic Avian Influenza Viruses in Southern China, 2014

    PubMed Central

    Jiao, Peirong; Cui, Jin; Song, Yafen; Song, Hui; Zhao, Zhishan; Wu, Siyu; Qu, Nannan; Wang, Nianchen; Ouyang, Guowen; Liao, Ming

    2016-01-01

    New reassortant H5N6 highly pathogenic avian influenza viruses (AIVs) were isolated from apparently healthy domestic ducks in Southern China in 2014. Our results show that the viruses grew efficiently in eggs and replicated systemically in chickens. They were completely lethal in chicken (100% mortality), and the mean death time was 6 to 7 days post-inoculation. The viruses could transmit in chickens by naïve contact. BLAST analysis revealed that their HA gene was most closely related to A/wild duck/Shangdong/628/2011 (H5N1), and their NA genes were most closely related to A/swine/Guangdong/K6/2010 (H6N6). The other genes had the highest identity with A/wild duck/Fujian/1/2011(H5N1). The results of phylogenetic analysis showed that their HA genes clustered into clade 2.3.4.4 of the H5N1 viruses and all genes derived from H5 were Mix-like or H6-like viruses. Thus, the new H5N6 viruses were reassortmented of H5N1 and H6N6 virus. Therefore, the circulation of the new H5N6 AIVs may become a threat to poultry and human health. PMID:27242767

  14. Identifying risk factors of highly pathogenic avian influenza (H5N1 subtype) in Indonesia.

    PubMed

    Loth, Leo; Gilbert, Marius; Wu, Jianmei; Czarnecki, Christina; Hidayat, Muhammad; Xiao, Xiangming

    2011-10-01

    Highly pathogenic avian influenza (HPAI), subtype H5N1, was first officially reported in Indonesia in 2004. Since then the disease has spread and is now endemic in large parts of the country. This study investigated the statistical relationship between a set of risk factors and the presence or absence of HPAI in Indonesia during 2006 and 2007. HPAI was evaluated through participatory disease surveillance (PDS) in backyard village chickens (the study population), and risk factors included descriptors of people and poultry distribution (separating chickens, ducks and production sectors), poultry movement patterns and agro-ecological conditions. The study showed that the risk factors "elevation", "human population density" and "rice cropping" were significant in accounting for the spatial variation of the PDS-defined HPAI cases. These findings were consistent with earlier studies in Thailand and Vietnam. In addition "commercial poultry population", and two indicators of market locations and transport; "human settlements" and "road length", were identified as significant risk factors in the models. In contrast to several previous studies carried out in Southeast Asia, domestic backyard ducks were not found to be a significant risk factor in Indonesia. The study used surrogate estimates of market locations and marketing chains and further work should focus on the actual location of the live bird markets, and on the flow of live poultry and poultry products between them, so that patterns of possible transmission, and regions of particular risk could be better inferred. PMID:21813198

  15. Evolutionary Analysis of Inter-Farm Transmission Dynamics in a Highly Pathogenic Avian Influenza Epidemic

    PubMed Central

    Bataille, Arnaud; van der Meer, Frank; Stegeman, Arjan; Koch, Guus

    2011-01-01

    Phylogenetic studies have largely contributed to better understand the emergence, spread and evolution of highly pathogenic avian influenza during epidemics, but sampling of genetic data has never been detailed enough to allow mapping of the spatiotemporal spread of avian influenza viruses during a single epidemic. Here, we present genetic data of H7N7 viruses produced from 72% of the poultry farms infected during the 2003 epidemic in the Netherlands. We use phylogenetic analyses to unravel the pathways of virus transmission between farms and between infected areas. In addition, we investigated the evolutionary processes shaping viral genetic diversity, and assess how they could have affected our phylogenetic analyses. Our results show that the H7N7 virus was characterized by a high level of genetic diversity driven mainly by a high neutral substitution rate, purifying selection and limited positive selection. We also identified potential reassortment in the three genes that we have tested, but they had only a limited effect on the resolution of the inter-farm transmission network. Clonal sequencing analyses performed on six farm samples showed that at least one farm sample presented very complex virus diversity and was probably at the origin of chronological anomalies in the transmission network. However, most virus sequences could be grouped within clearly defined and chronologically sound clusters of infection and some likely transmission events between farms located 0.8–13 Km apart were identified. In addition, three farms were found as most likely source of virus introduction in distantly located new areas. These long distance transmission events were likely facilitated by human-mediated transport, underlining the need for strict enforcement of biosafety measures during outbreaks. This study shows that in-depth genetic analysis of virus outbreaks at multiple scales can provide critical information on virus transmission dynamics and can be used to increase

  16. Identification of Highly Variable Supernumerary Chromosome Segments in an Asexual Pathogen.

    PubMed

    Huang, Xiaoqiu; Das, Anindya; Sahu, Binod B; Srivastava, Subodh K; Leandro, Leonor F; O'Donnell, Kerry; Bhattacharyya, Madan K

    2016-01-01

    Supernumerary chromosome segments are known to harbor different transposons from their essential counterparts. The aim of this study was to investigate the role of transposons in the origin and evolution of supernumerary segments in the asexual fungal pathogen Fusarium virguliforme. We compared the genomes of 11 isolates comprising six Fusarium species that cause soybean sudden death syndrome (SDS) or bean root rot (BRR), and identified significant levels of genetic variation in A+T-rich repeat blocks of the essential chromosomes and in A+T-neutral regions of the supernumerary segments. The A+T-rich repeat blocks in the essential chromosomes were highly variable between F. virguliforme and non-F. virguliforme isolates, but were scarcely variable between F. virguliforme isolates. The A+T-neutral regions in the supernumerary segments, however, were highly variable between F. virguliforme isolates, with a statistically significant number (21 standard deviations above the mean) of single nucleotide polymorphisms (SNPs). And supernumerary sequence types and rearrangement patterns of some F. virguliforme isolates were present in an isolate of F. cuneirostrum but not in the other F. virguliforme isolates. The most variable and highly expressed region in the supernumerary segments contained an active DNA transposon that was a most conserved match between F. virguliforme and the unrelated fungus Tolypocladium inflatum. This transposon was absent from two of the F. virguliforme isolates. Furthermore, transposons in the supernumerary segments of some F. virguliforme isolates were present in non-F. virguliforme isolates, but were absent from the other F. virguliforme isolates. Two supernumerary P450 enzymes were 43% and 57% identical to their essential counterparts. This study has raised the possibility that transposons generate genetic variation in supernumerary chromosome segments by frequent horizontal transfer within and between closely related species. PMID:27341103

  17. Identification of Highly Variable Supernumerary Chromosome Segments in an Asexual Pathogen

    PubMed Central

    Huang, Xiaoqiu; Das, Anindya; Sahu, Binod B.; Srivastava, Subodh K.; Leandro, Leonor F.; O’Donnell, Kerry; Bhattacharyya, Madan K.

    2016-01-01

    Supernumerary chromosome segments are known to harbor different transposons from their essential counterparts. The aim of this study was to investigate the role of transposons in the origin and evolution of supernumerary segments in the asexual fungal pathogen Fusarium virguliforme. We compared the genomes of 11 isolates comprising six Fusarium species that cause soybean sudden death syndrome (SDS) or bean root rot (BRR), and identified significant levels of genetic variation in A+T-rich repeat blocks of the essential chromosomes and in A+T-neutral regions of the supernumerary segments. The A+T-rich repeat blocks in the essential chromosomes were highly variable between F. virguliforme and non-F. virguliforme isolates, but were scarcely variable between F. virguliforme isolates. The A+T-neutral regions in the supernumerary segments, however, were highly variable between F. virguliforme isolates, with a statistically significant number (21 standard deviations above the mean) of single nucleotide polymorphisms (SNPs). And supernumerary sequence types and rearrangement patterns of some F. virguliforme isolates were present in an isolate of F. cuneirostrum but not in the other F. virguliforme isolates. The most variable and highly expressed region in the supernumerary segments contained an active DNA transposon that was a most conserved match between F. virguliforme and the unrelated fungus Tolypocladium inflatum. This transposon was absent from two of the F. virguliforme isolates. Furthermore, transposons in the supernumerary segments of some F. virguliforme isolates were present in non-F. virguliforme isolates, but were absent from the other F. virguliforme isolates. Two supernumerary P450 enzymes were 43% and 57% identical to their essential counterparts. This study has raised the possibility that transposons generate genetic variation in supernumerary chromosome segments by frequent horizontal transfer within and between closely related species. PMID:27341103

  18. Hall effect and band-like carrier transport in high mobility polymer transistors

    NASA Astrophysics Data System (ADS)

    Yamashita, Yu; Hinkel, Felix; Marszalek, Tomasz; Zajaczkowski, Wojciech; Pisula, Wojciech; Baumgarten, Martin; Matsui, Hiroyuki; Müllen, Klaus; Takeya, Jun; Takeya group Team, Prof.; Müllen group Team, Prof.

    A microscopic understanding of charge carrier transport in polymeric semiconductors is essential to improve the state of the art of flexible or printed electronic devices. In particular, thin-film field-effect transistors based on donor-acceptor polymers are in the focus of current literature reaching high charge-carrier mobility. In this work, we demonstrate the Hall effect and the temperature dependence of the charge carrier mobility based on uniaxially ordered CDT-BTZ donor-acceptor copolymer films. Uniaxially ordered films of CDT-BTZ with hexadecyl (C16) and eicosyl (C20) sidechains showed mobility of 5.6 cm2/Vs and 11.4 cm2/Vs respectively. The activation energy of the mobility decreased with the increasing carrier density, and finally the negative temperature dependence of the mobility was observed. Both polymers showed Hall effect, which also indicates the presence of extended electronic states. The temperature and carrier density dependence will be further discussed in the presentation.

  19. Investigating the Mobility of Light Autonomous Tracked Vehicles using a High Performance Computing Simulation Capability

    NASA Technical Reports Server (NTRS)

    Negrut, Dan; Mazhar, Hammad; Melanz, Daniel; Lamb, David; Jayakumar, Paramsothy; Letherwood, Michael; Jain, Abhinandan; Quadrelli, Marco

    2012-01-01

    This paper is concerned with the physics-based simulation of light tracked vehicles operating on rough deformable terrain. The focus is on small autonomous vehicles, which weigh less than 100 lb and move on deformable and rough terrain that is feature rich and no longer representable using a continuum approach. A scenario of interest is, for instance, the simulation of a reconnaissance mission for a high mobility lightweight robot where objects such as a boulder or a ditch that could otherwise be considered small for a truck or tank, become major obstacles that can impede the mobility of the light autonomous vehicle and negatively impact the success of its mission. Analyzing and gauging the mobility and performance of these light vehicles is accomplished through a modeling and simulation capability called Chrono::Engine. Chrono::Engine relies on parallel execution on Graphics Processing Unit (GPU) cards.

  20. Bipolar molecular composites: a new class of high-electron-mobility organic solids

    NASA Astrophysics Data System (ADS)

    Lin, Liang-Bih; Jenekhe, Samson A.; Borsenberger, Paul M.

    1997-10-01

    We describe high electron mobility in organic solids in the form of bipolar molecular composites of N,N'-bis(1,2-dimethylpropyl)-1,4,5,8-naphthalenetetracarboxylic diimide (NTDI) and tri-p-tolylaniine (TTA). The electron mobility in the NTDI/TTA composites is ~2 x 10 cm2/Vs, which is a factor of 4 to 6 higher than in pure NTDI and isone of the highest values reported for disordered organic solids. The field and temperature dependencies of the charge mobility can be described using the disorder formalism due to Bassler and co-workers, which provides an estimation of the energy width σ of the hopping site manifold. Analysis of the data gave σ=0.081 and 0.060 eV for the electron and hole mobilities in a NTDI/TTA composite of 0.5510.45 molar ratio. The energetic disorder for electron transport in the bipolar composites is substantially lower than for pure NTDI, which is 0.093 eV. The results suggest that the observed enhancement arises from a substantial reduction of energetic disorder in the electron transport manifold of the bipolar composites. The reduction of energetic disorder may be due to intermolecular charge transfer between NTDI and TTA. Such a charge transfer could stabilize the electron transport manifold by better charge delocalization, and consequently, less energetic disorder. Another possible reason for the observed enhanced electron mobility is the reduction of NTDI dimers that can act as carrier traps by the presence of TTA molecules in the bipolar composites. These results also suggest that bipolar composites represent a promising new class of high electron mobility organic solids.

  1. Evidence of infection by H5N2 highly pathogenic avian influenza viruses in healthy wild waterfowl

    USGS Publications Warehouse

    Gaidet, N.; Cattoli, G.; Hammoumi, S.; Newman, S.H.; Hagemeijer, W.; Takekawa, J.Y.; Cappelle, J.; Dodman, T.; Joannis, T.; Gil, P.; Monne, I.; Fusaro, A.; Capua, I.; Manu, S.; Micheloni, P.; Ottosson, U.; Mshelbwala, J.H.; Lubroth, J.; Domenech, J.; Monicat, F.

    2008-01-01

    The potential existence of a wild bird reservoir for highly pathogenic avian influenza (HPAI) has been recently questioned by the spread and the persisting circulation of H5N1 HPAI viruses, responsible for concurrent outbreaks in migratory and domestic birds over Asia, Europe, and Africa. During a large-scale surveillance programme over Eastern Europe, the Middle East, and Africa, we detected avian influenza viruses of H5N2 subtype with a highly pathogenic (HP) viral genotype in healthy birds of two wild waterfowl species sampled in Nigeria. We monitored the survival and regional movements of one of the infected birds through satellite telemetry, providing a rare evidence of a non-lethal natural infection by an HP viral genotype in wild birds. Phylogenetic analysis of the H5N2 viruses revealed close genetic relationships with H5 viruses of low pathogenicity circulating in Eurasian wild and domestic ducks. In addition, genetic analysis did not reveal known gallinaceous poultry adaptive mutations, suggesting that the emergence of HP strains could have taken place in either wild or domestic ducks or in non-gallinaceous species. The presence of coexisting but genetically distinguishable avian influenza viruses with an HP viral genotype in two cohabiting species of wild waterfowl, with evidence of non-lethal infection at least in one species and without evidence of prior extensive circulation of the virus in domestic poultry, suggest that some strains with a potential high pathogenicity for poultry could be maintained in a community of wild waterfowl.

  2. Evidence of Infection by H5N2 Highly Pathogenic Avian Influenza Viruses in Healthy Wild Waterfowl

    PubMed Central

    Hammoumi, Saliha; Newman, Scott H.; Hagemeijer, Ward; Takekawa, John Y.; Cappelle, Julien; Dodman, Tim; Joannis, Tony; Gil, Patricia; Monne, Isabella; Fusaro, Alice; Capua, Ilaria; Manu, Shiiwuua; Micheloni, Pierfrancesco; Ottosson, Ulf; Mshelbwala, John H.; Lubroth, Juan; Domenech, Joseph; Monicat, François

    2008-01-01

    The potential existence of a wild bird reservoir for highly pathogenic avian influenza (HPAI) has been recently questioned by the spread and the persisting circulation of H5N1 HPAI viruses, responsible for concurrent outbreaks in migratory and domestic birds over Asia, Europe, and Africa. During a large-scale surveillance programme over Eastern Europe, the Middle East, and Africa, we detected avian influenza viruses of H5N2 subtype with a highly pathogenic (HP) viral genotype in healthy birds of two wild waterfowl species sampled in Nigeria. We monitored the survival and regional movements of one of the infected birds through satellite telemetry, providing a rare evidence of a non-lethal natural infection by an HP viral genotype in wild birds. Phylogenetic analysis of the H5N2 viruses revealed close genetic relationships with H5 viruses of low pathogenicity circulating in Eurasian wild and domestic ducks. In addition, genetic analysis did not reveal known gallinaceous poultry adaptive mutations, suggesting that the emergence of HP strains could have taken place in either wild or domestic ducks or in non-gallinaceous species. The presence of coexisting but genetically distinguishable avian influenza viruses with an HP viral genotype in two cohabiting species of wild waterfowl, with evidence of non-lethal infection at least in one species and without evidence of prior extensive circulation of the virus in domestic poultry, suggest that some strains with a potential high pathogenicity for poultry could be maintained in a community of wild waterfowl. PMID:18704172

  3. Mapping population and pathogen movements

    PubMed Central

    Tatem, Andrew J.

    2014-01-01

    For most of human history, populations have been relatively isolated from each other, and only recently has there been extensive contact between peoples, flora and fauna from both old and new worlds. The reach, volume and speed of modern travel are unprecedented, with human mobility increasing in high income countries by over 1000-fold since 1800. This growth is putting people at risk from the emergence of new strains of familiar diseases, and from completely new diseases, while ever more cases of the movement of both disease vectors and the diseases they carry are being seen. Pathogens and their vectors can now move further, faster and in greater numbers than ever before. Equally however, we now have access to the most detailed and comprehensive datasets on human mobility and pathogen distributions ever assembled, in order to combat these threats. This short review paper provides an overview of these datasets, with a particular focus on low income regions, and covers briefly approaches used to combine them to help us understand and control some of the negative effects of population and pathogen movements. PMID:24480992

  4. Mapping population and pathogen movements.

    PubMed

    Tatem, Andrew J

    2014-03-01

    For most of human history, populations have been relatively isolated from each other, and only recently has there been extensive contact between peoples, flora and fauna from both old and new worlds. The reach, volume and speed of modern travel are unprecedented, with human mobility increasing in high income countries by over 1000-fold since 1800. This growth is putting people at risk from the emergence of new strains of familiar diseases, and from completely new diseases, while ever more cases of the movement of both disease vectors and the diseases they carry are being seen. Pathogens and their vectors can now move further, faster and in greater numbers than ever before. Equally however, we now have access to the most detailed and comprehensive datasets on human mobility and pathogen distributions ever assembled, in order to combat these threats. This short review paper provides an overview of these datasets, with a particular focus on low income regions, and covers briefly approaches used to combine them to help us understand and control some of the negative effects of population and pathogen movements. PMID:24480992

  5. Highly Pathogenic Influenza A(H5N1) Virus Survival in Complex Artificial Aquatic Biotopes

    PubMed Central

    Horm, Viseth Srey; Gutiérrez, Ramona A.; Nicholls, John M.; Buchy, Philippe

    2012-01-01

    Background Very little is known regarding the persistence of Highly Pathogenic Avian Influenza (HPAI) H5N1 viruses in aquatic environments in tropical countries, although environmental materials have been suggested to play a role as reservoirs and sources of transmission for H5N1 viruses. Methodology/Principal Findings The survival of HPAI H5N1 viruses in experimental aquatic biotopes (water, mud, aquatic flora and fauna) relevant to field conditions in Cambodia was investigated. Artificial aquatic biotopes, including simple ones containing only mud and water, and complex biotopes involving the presence of aquatic flora and fauna, were set up. They were experimentally contaminated with H5N1 virus. The persistence of HPAI H5N1 virus (local avian and human isolates) was determined by virus isolation in embryonated chicken eggs and by real-time reverse-polymerase chain reaction. Persistence of infectious virus did not exceed 4 days, and was only identified in rain water. No infectious virus particles were detected in pond and lake water or mud even when high inoculum doses were used. However, viral RNA persisted up to 20 days in rain water and 7 days in pond or lake water. Viral RNA was also detected in mud samples, up to 14 days post-contamination in several cases. Infectious virus and viral RNA was detected in few cases in the aquatic fauna and flora, especially in bivalves and labyrinth fish, although these organisms seemed to be mostly passive carriers of the virus rather than host allowing virus replication. Conclusions/Significance Although several factors for the survival and persistence of HPAI viruses in the environment are still to be elucidated, and are particularly hard to control in laboratory conditions, our results, along with previous data, support the idea that environmental surveillance is of major relevance for avian influenza control programs. PMID:22514622

  6. Intersubtype Reassortments of H5N1 Highly Pathogenic Avian Influenza Viruses Isolated from Quail.

    PubMed

    Nguyen, Tinh Huu; Than, Van Thai; Thanh, Hien Dang; Hung, Vu-Khac; Nguyen, Duc Tan; Kim, Wonyong

    2016-01-01

    H5N1 highly pathogenic avian influenza (HPAI) viruses are considered a threat to national animal industries, causing production losses and high mortality in domestic poultry. In recent years, quail has become a popular terrestrial poultry species raised for production of meat and eggs in Asia. In this study, to better understand the roles of quail in H5N1 viral evolution, two H5N1-positive samples, designated A/quail/Vietnam/CVVI-49/2010 (CVVI-49/2010) and A/quail/Vietnam/CVVI-50/2014 (CVVI-50/2014), were isolated from quail during H5N1 outbreaks in Vietnam, and their whole genome were analyzed. The phylogenetic analysis reveals new evolutionary variation in the worldwide H5N1 viruses. The quail HA genes were clustered into clades 1.1.1 (CVVI-49/2010) and clade 2.3.2.1c (CVVI-50/2014), which may have evolved from viruses circulating from chickens and/or ducks in Cambodia, mainland of China, Taiwan, Indonesia, and South Korea in recent years. Interestingly, the M2 gene of the CVVI-49/2010 strain contained amino acid substitutions at position 26L-I and 31S-N that are related to amantadine-resistance. In particular, the CVVI-50/2014 strain revealed evidence of multiple intersubtype reassortment events between virus clades 2.3.2.1c, 2.3.2.1b, and 2.3.2.1a. Data from this study supports the possible role of quail as an important intermediate host in avian influenza virus evolution. Therefore, additional surveillance is needed to monitor these HPAI viruses both serologically and virologically in quail. PMID:26900963

  7. Evolution of highly pathogenic avian H5N1 influenza viruses

    SciTech Connect

    Macken, Catherine A; Green, Margaret A

    2009-01-01

    Highly pathogenic avian H5N1 viruses have circulated in Southeast Asia for more than a decade, are now endemic in parts of this region, and have also spread to more than 60 countries on three continents. The evolution of these viruses is characterized by frequent reassortment events that have created a significant number of different genotypes, both transient and longer lasting. However, fundamental questions remain about the generation and perpetuation of this substantial genetic diversity. These gaps in understanding may, in part, be due to the difficulties of genotyping closely related viruses, and limitations in the size of the data sets used in analysis. Using our recently published novel genotyping procedure ('two-time test'), which is amenable to high throughput analysis and provides an increased level of resolution relative to previous analyses, we propose a detailed model for the evolution and diversification of avian H5N1 viruses. Our analysis suggests that (i) all current H5N1 genotypes are derived from a single, clearly defined sequence of initial reassortment events; (ii) reassortment of the polymerase and NP genes may have played an important role in avian H5N1 virus evolution; (iii) the current genotype Z viruses have diverged into three distinguishable sub-genotypes in the absence of reassortment; (iv) some potentially significant molecular changes appear to be correlated with particular genotypes (for example, reassortment of the internal genes is often paralleled by a change in the HA clade); and (v) as noted in earlier studies of avian influenza A virus evolution, novel segments are typically derived from different donors (i.e., there is no obvious pattern of gene linkage in reassortment). The model of avian H5N1 viral evolution by reassortment and mutation that emerges from our study provides a context within which significant amino acid changes may be revealed; it also may help in predicting the 'success' of newly emerging avian H5N1 viruses.

  8. The Complete Genome Sequence and Comparative Genome Analysis of the High Pathogenicity Yersinia enterocolitica Strain 8081

    PubMed Central

    Thomson, Nicholas R; Howard, Sarah; Wren, Brendan W; Holden, Matthew T. G; Crossman, Lisa; Challis, Gregory L; Churcher, Carol; Mungall, Karen; Brooks, Karen; Chillingworth, Tracey; Feltwell, Theresa; Abdellah, Zahra; Hauser, Heidi; Jagels, Kay; Maddison, Mark; Moule, Sharon; Sanders, Mandy; Whitehead, Sally; Quail, Michael A; Dougan, Gordon; Parkhill, Julian; Prentice, Michael B

    2006-01-01

    The human enteropathogen, Yersinia enterocolitica, is a significant link in the range of Yersinia pathologies extending from mild gastroenteritis to bubonic plague. Comparison at the genomic level is a key step in our understanding of the genetic basis for this pathogenicity spectrum. Here we report the genome of Y. enterocolitica strain 8081 (serotype 0:8; biotype 1B) and extensive microarray data relating to the genetic diversity of the Y. enterocolitica species. Our analysis reveals that the genome of Y. enterocolitica strain 8081 is a patchwork of horizontally acquired genetic loci, including a plasticity zone of 199 kb containing an extraordinarily high density of virulence genes. Microarray analysis has provided insights into species-specific Y. enterocolitica gene functions and the intraspecies differences between the high, low, and nonpathogenic Y. enterocolitica biotypes. Through comparative genome sequence analysis we provide new information on the evolution of the Yersinia. We identify numerous loci that represent ancestral clusters of genes potentially important in enteric survival and pathogenesis, which have been lost or are in the process of being lost, in the other sequenced Yersinia lineages. Our analysis also highlights large metabolic operons in Y. enterocolitica that are absent in the related enteropathogen, Yersinia pseudotuberculosis, indicating major differences in niche and nutrients used within the mammalian gut. These include clusters directing, the production of hydrogenases, tetrathionate respiration, cobalamin synthesis, and propanediol utilisation. Along with ancestral gene clusters, the genome of Y. enterocolitica has revealed species-specific and enteropathogen-specific loci. This has provided important insights into the pathology of this bacterium and, more broadly, into the evolution of the genus. Moreover, wider investigations looking at the patterns of gene loss and gain in the Yersinia have highlighted common themes in the

  9. Intersubtype Reassortments of H5N1 Highly Pathogenic Avian Influenza Viruses Isolated from Quail

    PubMed Central

    Nguyen, Tinh Huu; Than, Van Thai; Thanh, Hien Dang; Hung, Vu-Khac; Nguyen, Duc Tan; Kim, Wonyong

    2016-01-01

    H5N1 highly pathogenic avian influenza (HPAI) viruses are considered a threat to national animal industries, causing production losses and high mortality in domestic poultry. In recent years, quail has become a popular terrestrial poultry species raised for production of meat and eggs in Asia. In this study, to better understand the roles of quail in H5N1 viral evolution, two H5N1-positive samples, designated A/quail/Vietnam/CVVI-49/2010 (CVVI-49/2010) and A/quail/Vietnam/CVVI-50/2014 (CVVI-50/2014), were isolated from quail during H5N1 outbreaks in Vietnam, and their whole genome were analyzed. The phylogenetic analysis reveals new evolutionary variation in the worldwide H5N1 viruses. The quail HA genes were clustered into clades 1.1.1 (CVVI-49/2010) and clade 2.3.2.1c (CVVI-50/2014), which may have evolved from viruses circulating from chickens and/or ducks in Cambodia, mainland of China, Taiwan, Indonesia, and South Korea in recent years. Interestingly, the M2 gene of the CVVI-49/2010 strain contained amino acid substitutions at position 26L-I and 31S-N that are related to amantadine-resistance. In particular, the CVVI-50/2014 strain revealed evidence of multiple intersubtype reassortment events between virus clades 2.3.2.1c, 2.3.2.1b, and 2.3.2.1a. Data from this study supports the possible role of quail as an important intermediate host in avian influenza virus evolution. Therefore, additional surveillance is needed to monitor these HPAI viruses both serologically and virologically in quail. PMID:26900963

  10. The complete genome sequence and comparative genome analysis of the high pathogenicity Yersinia enterocolitica strain 8081.

    PubMed

    Thomson, Nicholas R; Howard, Sarah; Wren, Brendan W; Holden, Matthew T G; Crossman, Lisa; Challis, Gregory L; Churcher, Carol; Mungall, Karen; Brooks, Karen; Chillingworth, Tracey; Feltwell, Theresa; Abdellah, Zahra; Hauser, Heidi; Jagels, Kay; Maddison, Mark; Moule, Sharon; Sanders, Mandy; Whitehead, Sally; Quail, Michael A; Dougan, Gordon; Parkhill, Julian; Prentice, Michael B

    2006-12-15

    The human enteropathogen, Yersinia enterocolitica, is a significant link in the range of Yersinia pathologies extending from mild gastroenteritis to bubonic plague. Comparison at the genomic level is a key step in our understanding of the genetic basis for this pathogenicity spectrum. Here we report the genome of Y. enterocolitica strain 8081 (serotype 0:8; biotype 1B) and extensive microarray data relating to the genetic diversity of the Y. enterocolitica species. Our analysis reveals that the genome of Y. enterocolitica strain 8081 is a patchwork of horizontally acquired genetic loci, including a plasticity zone of 199 kb containing an extraordinarily high density of virulence genes. Microarray analysis has provided insights into species-specific Y. enterocolitica gene functions and the intraspecies differences between the high, low, and nonpathogenic Y. enterocolitica biotypes. Through comparative genome sequence analysis we provide new information on the evolution of the Yersinia. We identify numerous loci that represent ancestral clusters of genes potentially important in enteric survival and pathogenesis, which have been lost or are in the process of being lost, in the other sequenced Yersinia lineages. Our analysis also highlights large metabolic operons in Y. enterocolitica that are absent in the related enteropathogen, Yersinia pseudotuberculosis, indicating major differences in niche and nutrients used within the mammalian gut. These include clusters directing, the production of hydrogenases, tetrathionate respiration, cobalamin synthesis, and propanediol utilisation. Along with ancestral gene clusters, the genome of Y. enterocolitica has revealed species-specific and enteropathogen-specific loci. This has provided important insights into the pathology of this bacterium and, more broadly, into the evolution of the genus. Moreover, wider investigations looking at the patterns of gene loss and gain in the Yersinia have highlighted common themes in the

  11. Inhibition of highly pathogenic PRRSV replication in MARC-145 cells by artificial microRNAs

    PubMed Central

    2011-01-01

    Background Highly pathogenic porcine reproductive and respiratory syndrome (HP-PRRS) has caused large economic losses in swine industry in recent years. However, current antiviral strategy could not effectively prevent and control this disease. In this research, five artificial microRNAs (amiRNAs) respectively targeted towards ORF5 (amirGP5-243, -370) and ORF6 (amirM-82, -217,-263) were designed and incorporated into a miRNA-based vector that mimics the backbone of murine miR-155 and permits high expression of amiRNAs in a GFP fused form mediated by RNA Pol II promoter CMV. Results It was found that amirGP5-370 could effectively inhibit H-PRRSV replication. The amirM-263-M-263, which was a dual pre-amiRNA expression cassette where two amirM-263s were chained, showed stronger virus inhibitory effects than single amirM-263. H-PRRSV replication was inhibited up to 120 hours in the MARC-145 cells which were stably transduced by recombinant lentiviruses (Lenti-amirGP5-370, -amirM-263-M-263). Additionally, efficacious dose of amirGP5-370 and amirM-263 expression did not trigger the innate interferon response. Conclusions Our study is the first attempt to suppress H-PRRSV replication in MARC-145 cells through vector-based and lentiviral mediated amiRNAs targeting GP5 or M proteins coding sequences of PRRSV, which indicated that artificial microRNAs and recombinant lentiviruses might be applied to be a new potent anti-PRRSV strategy. PMID:22040357

  12. Interoceptive threat leads to defensive mobilization in highly anxiety sensitive persons.

    PubMed

    Melzig, Christiane A; Holtz, Katharina; Michalowski, Jaroslaw M; Hamm, Alfons O

    2011-06-01

    To study defensive mobilization elicited by the exposure to interoceptive arousal sensations, we exposed highly anxiety sensitive students to a symptom provocation task. Symptom reports, autonomic arousal, and the startle eyeblink response were monitored during guided hyperventilation and a recovery period in 26 highly anxiety sensitive persons and 22 controls. Normoventilation was used as a non-provocative comparison condition. Hyperventilation led to autonomic arousal and a marked increase in somatic symptoms. While high and low anxiety sensitive persons did not differ in their defensive activation during hyperventilation, group differences were detected during early recovery. Highly anxiety sensitive students exhibited a potentiation of startle response magnitudes and increased autonomic arousal after hyper- as compared to after normoventilation, indicating defensive mobilization evoked by the prolonged presence of feared somatic sensations. PMID:21073480

  13. Homo- and Heterosubtypic Low Pathogenic Avian Influenza Exposure on H5N1 Highly Pathogenic Avian Influenza Virus Infection in Wood Ducks (Aix sponsa)

    PubMed Central

    Costa, Taiana P.; Brown, Justin D.; Howerth, Elizabeth W.; Stallknecht, David E.; Swayne, David E.

    2011-01-01

    Wild birds in the Orders Anseriformes and Charadriiformes are the natural reservoirs for avian influenza (AI) viruses. Although they are often infected with multiple AI viruses, the significance and extent of acquired immunity in these populations is not understood. Pre-existing immunity to AI virus has been shown to modulate the outcome of a highly pathogenic avian influenza (HPAI) virus infection in multiple domestic avian species, but few studies have addressed this effect in wild birds. In this study, the effect of pre-exposure to homosubtypic (homologous hemagglutinin) and heterosubtypic (heterologous hemagglutinin) low pathogenic avian influenza (LPAI) viruses on the outcome of a H5N1 HPAI virus infection in wood ducks (Aix sponsa) was evaluated. Pre-exposure of wood ducks to different LPAI viruses did not prevent infection with H5N1 HPAI virus, but did increase survival associated with H5N1 HPAI virus infection. The magnitude of this effect on the outcome of the H5N1 HPAI virus infection varied between different LPAI viruses, and was associated both with efficiency of LPAI viral replication in wood ducks and the development of a detectable humoral immune response. These observations suggest that in naturally occurring outbreaks of H5N1 HPAI, birds with pre-existing immunity to homologous hemagglutinin or neuraminidase subtypes of AI virus may either survive H5N1 HPAI virus infection or live longer than naïve birds and, consequently, could pose a greater risk for contributing to viral transmission and dissemination. The mechanisms responsible for this protection and/or the duration of this immunity remain unknown. The results of this study are important for surveillance efforts and help clarify epidemiological data from outbreaks of H5N1 HPAI virus in wild bird populations. PMID:21253608

  14. Performance of AlGaN/GaN high electron mobility transistors at nanoscale gate lengths.

    PubMed

    Johnson, J W; Ren, F; Pearton, S J; Baca, A G; Han, J; Dabiran, A M; Chow, P P

    2002-01-01

    The DC and RF performance of AlGaN/GaN high electron mobility transistors with nanoscale gate lengths is presented. The layer structures were grown by either metal organic chemical vapor deposition or rf plasma-assisted molecular beam epitaxy. Excellent scaling properties were observed as a function of both gate length and width and confirm that these devices are well suited to both high speed switching and power microwave applications. PMID:12908259

  15. Isoindigo-based polymer field-effect transistors: effects of selenophene-substitution on high charge carrier mobility.

    PubMed

    Park, Kwang Hun; Cheon, Kwang Hee; Lee, Yun-Ji; Chung, Dae Sung; Kwon, Soon-Ki; Kim, Yun-Hi

    2015-05-11

    We show that selenophene-substitution can be an efficient synthetic strategy toward high charge carrier mobility of isoindigo (IID)-based copolymers when their side chains are optimized. A high mobility of 5.8 cm(2) V(-1) s(-1) is demonstrated by a strategically designed IID-based polymer, with both side-chain adjustment and selenophene-substitution. PMID:25871952

  16. High-Throughput Electrophoretic Mobility Shift Assays for Quantitative Analysis of Molecular Binding Reactions

    PubMed Central

    2015-01-01

    We describe a platform for high-throughput electrophoretic mobility shift assays (EMSAs) for identification and characterization of molecular binding reactions. A photopatterned free-standing polyacrylamide gel array comprised of 8 mm-scale polyacrylamide gel strips acts as a chassis for 96 concurrent EMSAs. The high-throughput EMSAs was employed to assess binding of the Vc2 cyclic-di-GMP riboswitch to its ligand. In optimizing the riboswitch EMSAs on the free-standing polyacrylamide gel array, three design considerations were made: minimizing sample injection dispersion, mitigating evaporation from the open free-standing polyacrylamide gel structures during electrophoresis, and controlling unit-to-unit variation across the large-format free-standing polyacrylamide gel array. Optimized electrophoretic mobility shift conditions allowed for 10% difference in mobility shift baseline resolution within 3 min. The powerful 96-plex EMSAs increased the throughput to ∼10 data/min, notably more efficient than either conventional slab EMSAs (∼0.01 data/min) or even microchannel based microfluidic EMSAs (∼0.3 data/min). The free-standing polyacrylamide gel EMSAs yielded reliable quantification of molecular binding and associated mobility shifts for a riboswitch–ligand interaction, thus demonstrating a screening assay platform suitable for riboswitches and potentially a wide range of RNA and other macromolecular targets. PMID:25233437

  17. Evaluating high-throughput ab initio gene finders to discover proteins encoded in eukaryotic pathogen genomes missed by laboratory techniques.

    PubMed

    Goodswen, Stephen J; Kennedy, Paul J; Ellis, John T

    2012-01-01

    Next generation sequencing technology is advancing genome sequencing at an unprecedented level. By unravelling the code within a pathogen's genome, every possible protein (prior to post-translational modifications) can theoretically be discovered, irrespective of life cycle stages and environmental stimuli. Now more than ever there is a great need for high-throughput ab initio gene finding. Ab initio gene finders use statistical models to predict genes and their exon-intron structures from the genome sequence alone. This paper evaluates whether existing ab initio gene finders can effectively predict genes to deduce proteins that have presently missed capture by laboratory techniques. An aim here is to identify possible patterns of prediction inaccuracies for gene finders as a whole irrespective of the target pathogen. All currently available ab initio gene finders are considered in the evaluation but only four fulfil high-throughput capability: AUGUSTUS, GeneMark_hmm, GlimmerHMM, and SNAP. These gene finders require training data specific to a target pathogen and consequently the evaluation results are inextricably linked to the availability and quality of the data. The pathogen, Toxoplasma gondii, is used to illustrate the evaluation methods. The results support current opinion that predicted exons by ab initio gene finders are inaccurate in the absence of experimental evidence. However, the results reveal some patterns of inaccuracy that are common to all gene finders and these inaccuracies may provide a focus area for future gene finder developers. PMID:23226328

  18. Molecular pathogenesis of H5 highly pathogenic avian influenza: the role of the haemagglutinin cleavage site motif.

    PubMed

    Luczo, Jasmina M; Stambas, John; Durr, Peter A; Michalski, Wojtek P; Bingham, John

    2015-11-01

    The emergence of H5N1 highly pathogenic avian influenza has caused a heavy socio-economic burden through culling of poultry to minimise human and livestock infection. Although human infections with H5N1 have to date been limited, concerns for the pandemic potential of this zoonotic virus have been greatly intensified following experimental evidence of aerosol transmission of H5N1 viruses in a mammalian infection model. In this review, we discuss the dominance of the haemagglutinin cleavage site motif as a pathogenicity determinant, the host-pathogen molecular interactions driving cleavage activation, reverse genetics manipulations and identification of residues key to haemagglutinin cleavage site functionality and the mechanisms of cell and tissue damage during H5N1 infection. We specifically focus on the disease in chickens, as it is in this species that high pathogenicity frequently evolves and from which transmission to the human population occurs. With >75% of emerging infectious diseases being of zoonotic origin, it is necessary to understand pathogenesis in the primary host to explain spillover events into the human population. PMID:26467906

  19. Modeling of high composition AlGaN channel high electron mobility transistors with large threshold voltage

    SciTech Connect

    Bajaj, Sanyam Hung, Ting-Hsiang; Akyol, Fatih; Nath, Digbijoy; Rajan, Siddharth

    2014-12-29

    We report on the potential of high electron mobility transistors (HEMTs) consisting of high composition AlGaN channel and barrier layers for power switching applications. Detailed two-dimensional (2D) simulations show that threshold voltages in excess of 3 V can be achieved through the use of AlGaN channel layers. We also calculate the 2D electron gas mobility in AlGaN channel HEMTs and evaluate their power figures of merit as a function of device operating temperature and Al mole fraction in the channel. Our models show that power switching transistors with AlGaN channels would have comparable on-resistance to GaN-channel based transistors for the same operation voltage. The modeling in this paper shows the potential of high composition AlGaN as a channel material for future high threshold enhancement mode transistors.

  20. Evolution of highly pathogenic avian influenza H5N1 viruses in Egypt indicating progressive adaptation.

    PubMed

    Arafa, A; Suarez, D; Kholosy, S G; Hassan, M K; Nasef, S; Selim, A; Dauphin, G; Kim, M; Yilma, J; Swayne, D; Aly, M M

    2012-10-01

    Highly pathogenic avian influenza (HPAI) virus of the H5N1 subtype was first diagnosed in poultry in Egypt in 2006, and since then the disease became enzootic in poultry throughout the country, affecting the poultry industry and village poultry as well as infecting humans. Vaccination has been used as a part of the control strategy to help to control the disease. Epidemiological data with sequence analysis of H5N1 viruses is important to link the mechanism of virus evolution in Egypt. This study describes the evolutionary pattern of Egyptian H5N1 viruses based on molecular characterization for the isolates collected from commercial poultry farms and village poultry from 2006 to 2011. Genetic analysis of the hemagglutinin (HA) gene was done by sequencing of the full-length H5 gene. The epidemiological pattern of disease outbreaks in Egyptian poultry farms seems to be seasonal with no specific geographic distribution across the country. The molecular epidemiological data revealed that there are two major groups of viruses: the classic group of subclade 2.2.1 and a variant group of 2.2.1.1. The classic group is prevailing mainly in village poultry and had fewer mutations compared to the originally introduced virus in 2006. Since 2009, this group has started to be transmitted back to commercial sectors. The variant group emerged by late 2007, was prevalent mainly in vaccinated commercial poultry, mutated continuously at a higher rate until 2010, and started to decline in 2011. Genetic analysis of the neuraminidase (NA) gene and the other six internal genes indicates a grouping of the Egyptian viruses similar to that obtained using the HA gene, with no obvious reassortments. The results of this study indicate that HPAI-H5N1 viruses are progressively evolving and adapting in Egypt and continue to acquire new mutations every season. PMID:22760662

  1. Continuing Reassortant of H5N6 Subtype Highly Pathogenic Avian Influenza Virus in Guangdong.

    PubMed

    Yuan, Runyu; Wang, Zheng; Kang, Yinfeng; Wu, Jie; Zou, Lirong; Liang, Lijun; Song, Yingchao; Zhang, Xin; Ni, Hanzhong; Lin, Jinyan; Ke, Changwen

    2016-01-01

    First identified in May 2014 in China's Sichuan Province, initial cases of H5N6 avian influenza virus (AIV) infection in humans raised great concerns about the virus's prevalence, origin, and development. To evaluate both AIV contamination in live poultry markets (LPMs) and the risk of AIV infection in humans, we have conducted surveillance of LPMs in Guangdong Province since 2013 as part of environmental sampling programs. With environmental samples associated with these LPMs, we performed genetic and phylogenetic analyses of 10 H5N6 AIVs isolated from different cities of Guangdong Province from different years. Results revealed that the H5N6 viruses were reassortants with hemagglutinin (HA) genes derived from clade 2.3.4.4 of H5-subtype AIV, yet neuraminidase (NA) genes derived from H6N6 AIV. Unlike the other seven H5N6 viruses isolated in first 7 months of 2014, all of which shared remarkable sequence similarity with the H5N1 AIV in all internal genes, the PB2 genes of GZ693, GZ670, and ZS558 more closely related to H6N6 AIV and the PB1 gene of GZ693 to the H3-subtype AIV. Phylogenetic analyses revealed that the environmental H5N6 AIV related closely to human H5N6 AIVs isolated in Guangdong. These results thus suggest that continued reassortment has enabled the emergence of a novel H5N6 virus in Guangdong, as well as highlight the potential risk of highly pathogenic H5N6 AIVs in the province. PMID:27148209

  2. 142 Sochi virus as a highly pathogenic and life-threatening agent

    PubMed Central

    Tkachenko, E.; Dzagurova, T.; Klempa, B.; Kruger, D.

    2014-01-01

    A new genotype of Dobrava-Belgrade virus (DOBV), Sochi virus, was found in the Black Sea field mouse, Apodemus ponticus. This mouse is naturally occurring in the Southern European Russia and transcaucasian countries between the Black and the Caspian Sea. Recently, cell culture isolates of Sochi virus have been generated from A. ponticus and an HFRS patient with fatal outcome. At the present state of knowledge, Sochi virus seems to be the most dangerous representative of DOBV. Virus diagnostics in patients was accomplished by immunofluorescence assay, serotyping of neutralizing antibodies, and RT-PCR amplification of viral genome segments. In phylogenetic analyses we found a spatial clustering of the viral nucleotide sequences derived from patients and mice trapped at different localities of the Russian Black Sea coast region demonstrating Sochi virus as the causal pathogenic agent in humans. We currently oversee in detail the clinical courses of 51 patients with confirmed Sochi virus infection. The case fatality rate was determined to be as high as 14%. Nearly 60% of clinical courses were defined as severe (including deaths) and nearly 40% as moderate. Four times more males than females were affected. Quite unusual for hantavirus disease, also young people became ill due to Sochi virus infection; 10% of patients were found between 7 and 15 years old and the age average of all patients was not much higher than 30 years. There is an urgent need to monitor the epidemiology of the new virus—not only because of its health-threatening character in this particular geographical area but also because of its potential ability to overcome host species barriers. Colonization of nearly related host species, as A. flavicollis or A. sylvaticus, by the virus could dramatically increase its geographical spread and consequently further enhance the danger for the human population.

  3. Continuing Reassortant of H5N6 Subtype Highly Pathogenic Avian Influenza Virus in Guangdong

    PubMed Central

    Yuan, Runyu; Wang, Zheng; Kang, Yinfeng; Wu, Jie; Zou, Lirong; Liang, Lijun; Song, Yingchao; Zhang, Xin; Ni, Hanzhong; Lin, Jinyan; Ke, Changwen

    2016-01-01

    First identified in May 2014 in China's Sichuan Province, initial cases of H5N6 avian influenza virus (AIV) infection in humans raised great concerns about the virus's prevalence, origin, and development. To evaluate both AIV contamination in live poultry markets (LPMs) and the risk of AIV infection in humans, we have conducted surveillance of LPMs in Guangdong Province since 2013 as part of environmental sampling programs. With environmental samples associated with these LPMs, we performed genetic and phylogenetic analyses of 10 H5N6 AIVs isolated from different cities of Guangdong Province from different years. Results revealed that the H5N6 viruses were reassortants with hemagglutinin (HA) genes derived from clade 2.3.4.4 of H5-subtype AIV, yet neuraminidase (NA) genes derived from H6N6 AIV. Unlike the other seven H5N6 viruses isolated in first 7 months of 2014, all of which shared remarkable sequence similarity with the H5N1 AIV in all internal genes, the PB2 genes of GZ693, GZ670, and ZS558 more closely related to H6N6 AIV and the PB1 gene of GZ693 to the H3-subtype AIV. Phylogenetic analyses revealed that the environmental H5N6 AIV related closely to human H5N6 AIVs isolated in Guangdong. These results thus suggest that continued reassortment has enabled the emergence of a novel H5N6 virus in Guangdong, as well as highlight the potential risk of highly pathogenic H5N6 AIVs in the province. PMID:27148209

  4. Highly Pathogenic Avian Influenza H5N1 in Mainland China

    PubMed Central

    Li, Xin-Lou; Liu, Kun; Yao, Hong-Wu; Sun, Ye; Chen, Wan-Jun; Sun, Ruo-Xi; de Vlas, Sake J.; Fang, Li-Qun; Cao, Wu-Chun

    2015-01-01

    Highly pathogenic avian influenza (HPAI) H5N1 has posed a significant threat to both humans and birds, and it has spanned large geographic areas and various ecological systems throughout Asia, Europe and Africa, but especially in mainland China. Great efforts in control and prevention of the disease, including universal vaccination campaigns in poultry and active serological and virological surveillance, have been undertaken in mainland China since the beginning of 2006. In this study, we aim to characterize the spatial and temporal patterns of HPAI H5N1, and identify influencing factors favoring the occurrence of HPAI H5N1 outbreaks in poultry in mainland China. Our study shows that HPAI H5N1 outbreaks took place sporadically after vaccination campaigns in poultry, and mostly occurred in the cold season. The positive tests in routine virological surveillance of HPAI H5N1 virus in chicken, duck, goose as well as environmental samples were mapped to display the potential risk distribution of the virus. Southern China had a higher positive rate than northern China, and positive samples were mostly detected from chickens in the north, while the majority were from duck in the south, and a negative correlation with monthly vaccination rates in domestic poultry was found (R = −0.19, p value = 0.005). Multivariate panel logistic regression identified vaccination rate, interaction between distance to the nearest city and national highway, interaction between distance to the nearest lake and wetland, and density of human population, as well as the autoregressive term in space and time as independent risk factors in the occurrence of HPAI H5N1 outbreaks, based on which a predicted risk map of the disease was derived. Our findings could provide new understanding of the distribution and transmission of HPAI H5N1 in mainland China and could be used to inform targeted surveillance and control efforts in both human and poultry populations to reduce the risk of future infections

  5. Low-temperature high-mobility amorphous IZO for silicon heterojunction solar cells

    SciTech Connect

    Morales-Masis, Monica; Martin De Nicolas, Silvia; Holovsky, Jakub; De Wolf, Stefaan; Ballif, Christophe

    2015-07-13

    Parasitic absorption in the transparent conductive oxide (TCO) front electrode is one of the limitations of silicon heterojunction (SHJ) solar cells efficiency. To avoid such absorption while retaining high conductivity, TCOs with high electron mobility are preferred over those with high carrier density. Here, we demonstrate improved SHJ solar cell efficiencies by applying high-mobility amorphous indium zinc oxide (a-IZO) as the front TCO. We sputtered a-IZO at low substrate temperature and low power density and investigated the optical and electrical properties, as well as subband tail formation-quantified by the Urbach energy (EU)-as a function of the sputtering oxygen partial pressure. We obtain an EU as low as 128 meV for films with the highest Hall mobility of 60 cm2/Vs. When comparing the performance of a-IZO films with indium tin oxide (ITO) and hydrogenated indium oxide (IO:H), we find that IO:H (115 cm2/Vs) exhibits a similar EU of 130 meV, while ITO (25 cm2/Vs) presents a much larger EU of up to 270 meV. The high film quality, indicated by the low EU, the high mobility, and low free carrier absorption of the developed a-IZO electrodes, result in a significant current improvement, achieving conversion efficiencies over 21.5%, outperforming those with standard ITO.

  6. Rapid detection of fungal pathogens in bronchoalveolar lavage samples using panfungal PCR combined with high resolution melting analysis.

    PubMed

    Bezdicek, Matej; Lengerova, Martina; Ricna, Dita; Weinbergerova, Barbora; Kocmanova, Iva; Volfova, Pavlina; Drgona, Lubos; Poczova, Miroslava; Mayer, Jiri; Racil, Zdenek

    2016-10-01

    Despite advances in the treatment of invasive fungal diseases (IFD), mortality rates remain high. Moreover, due to the expanding spectrum of causative agents, fast and accurate pathogen identification is necessary. We designed a panfungal polymerase chain reaction (PCR), which targets the highly variable ITS2 region of rDNA genes and uses high resolution melting analysis (HRM) for subsequent species identification. The sensitivity and specificity of this method was tested on a broad spectrum of the most clinically important fungal pathogens including Aspergillus spp., Candida spp. and mucormycetes. Despite the fact that fluid from bronchoalveolar lavage (BAL) is one of the most frequently tested materials there is a lack of literature sources aimed at panfungal PCR as an IFD diagnostic tool from BAL samples. The applicability of this method in routine practice was evaluated on 104 BAL samples from immunocompromised patients. Due to high ITS region variability, we obtained divergent melting peaks for different fungal species. Thirteen out of 18 patients with proven or probable IFD were positive. Therefore, the sensitivity, specificity, positive predictive value and negative predictive value of our method were 67%, 100%, 100%, and 94%, respectively. In our assay, fungal pathogens identification is based on HRM, therefore omitting the expensive and time consuming sequencing step. With the high specificity, positive and negative predictive values, short time needed to obtain a result, and low price, the presented assay is intended to be used as a quick screening method for patients at risk of IFD. PMID:27161789

  7. Pathogenicity Islands in Bacterial Pathogenesis

    PubMed Central

    Schmidt, Herbert; Hensel, Michael

    2004-01-01

    In this review, we focus on a group of mobile genetic elements designated pathogenicity islands (PAI). These elements play a pivotal role in the virulence of bacterial pathogens of humans and are also essential for virulence in pathogens of animals and plants. Characteristic molecular features of PAI of important human pathogens and their role in pathogenesis are described. The availability of a large number of genome sequences of pathogenic bacteria and their benign relatives currently offers a unique opportunity for the identification of novel pathogen-specific genomic islands. However, this knowledge has to be complemented by improved model systems for the analysis of virulence functions of bacterial pathogens. PAI apparently have been acquired during the speciation of pathogens from their nonpathogenic or environmental ancestors. The acquisition of PAI not only is an ancient evolutionary event that led to the appearance of bacterial pathogens on a timescale of millions of years but also may represent a mechanism that contributes to the appearance of new pathogens within a human life span. The acquisition of knowledge about PAI, their structure, their mobility, and the pathogenicity factors they encode not only is helpful in gaining a better understanding of bacterial evolution and interactions of pathogens with eukaryotic host cells but also may have important practical implications such as providing delivery systems for vaccination, tools for cell biology, and tools for the development of new strategies for therapy of bacterial infections. PMID:14726454

  8. High Mobility SiGe/Si Transistor Structures on Sapphire Substrates Using Ion Implantation

    NASA Technical Reports Server (NTRS)

    Alterovitz, S. A.; Mueller, C. H.; Croke, E. T.

    2003-01-01

    High mobility n-type SiGe/Si transistor structures have been fabricated on sapphire substrates by ion implanting phosphorus ions into strained 100 Angstrom thick silicon channels for the first time. The strained Si channels were sandwiched between Si(sub 0.7)Ge(sub 0.3) layers, which, in turn, were deposited on Si(sub 0.7)Ge(sub 0.3) virtual substrates and graded SiGe buffer layers. After the molecular beam epitaxy (MBE) film growth process was completed, ion thick silicon channels implantation and post-annealing were used to introduce donors. The phosphorous ions were preferentially located in the Si channel at a peak concentration of approximately 1x10(exp 18)/cu cm. Room temperature electron mobilities exceeding 750 sq cm/V-sec at carrier densities of 1x10(exp 12)/sq cm were measured. Electron concentration appears to be the key factor that determines mobility, with the highest mobility observed for electron densities in the 1 - 2x10(exp 12)/sq cm range.

  9. Metabolic Profiling of Human Blood by High Resolution Ion Mobility Mass Spectrometry (IM-MS)

    PubMed Central

    Dwivedi, Prabha; Schultz, Albert J.; Hill, Herbert H.

    2010-01-01

    A high resolution ion mobility time-of-flight mass spectrometer with electrospray ionization source (ESI-IM-MS) was evaluated as an analytical method for rapid analysis of complex biological samples such as human blood metabolome was investigated. The hybrid instrument (IM-MS) provided an average ion mobility resolving power of ~90 and a mass resolution of ~1500 (at m/z 100). A few µL of whole blood was extracted with methanol, centrifuged and infused into the IM-MS via an electrospray ionization source. Upon IM-MS profiling of the human blood metabolome approximately 1,100 metabolite ions were detected and 300 isomeric metabolites separated in short analyses time (30 minutes). Estimated concentration of the metabolites ranged from the low micromolar to the low nanomolar level. Various classes of metabolites (amino acids, organic acids, fatty acids, carbohydrates, purines and pyrimidines etc) were found to form characteristic mobility-mass correlation curves (MMCC) that aided in metabolite identification. Peaks corresponding to various sterol derivatives, estrogen derivatives, phosphocholines, prostaglandins, and cholesterol derivatives detected in the blood extract were found to occupy characteristic two dimensional IM-MS space. Low abundance metabolite peaks that can be lost in MS random noise were resolved from noise peaks by differentiation in mobility space. In addition, the peak capacity of MS increased six fold by coupling IMS prior to MS analysis. PMID:21113320

  10. Growth parameter optimization and interface treatment for enhanced electron mobility in heavily strained GaInAs/AlInAs high electron mobility transistor structures

    SciTech Connect

    Fedoryshyn, Yuriy; Ostinelli, Olivier; Alt, Andreas; Pallin, Angel; Bolognesi, Colombo R.

    2014-01-28

    The optimization of heavily strained Ga{sub 0.25}In{sub 0.75}As/Al{sub 0.48}In{sub 0.52}As high electron mobility transistor structures is discussed in detail. The growth parameters and the channel layer interfaces were optimized in order to maximize the mobility of the two-dimensional electron gas. Structures composed of an 11 nm thick channel layer and a 4 nm thick spacer layer exhibited electron mobilities as high as 15 100 cm{sup 2}/Vs and 70 000 cm{sup 2}/Vs at 300 and 77 K, respectively, for channels including InAs strained layers. The sheet carrier density was kept above 2.5 × 10{sup 12} cm{sup −2} throughout the entire study.

  11. High throughput screening strategies and technology platforms for detection of pathogens: An Introduction

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Globally, foodborne pathogens are a major public health concern. In this chapter, we provide a broad description of the problem of food-borne diseases and current and future detection technologies for food safety assurance and prevention of foodborne illnesses. Current detection approaches include s...

  12. Major Histocompatibility Complex and Background Genes in Chickens Influence Susceptibility to High Pathogenicity Avian Influenza Virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The chicken’s major histocompatibility complex (MHC) haplotype has profound influence on the resistance or susceptibility to certain pathogens such as B21 MHC haplotype confers resistance to Marek’s disease (MD). However, non-MHC genes are also important in disease resistance. For example, both line...

  13. Gene expression responses to highly pathogenic avian influenza H5N1 virus infections in ducks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Differences in host response to infection with avian influenza (AI) viruses were investigated by identifying genes differentially expressed in tissues of infected ducks. Clear differences in pathogenicity were observed among ducks inoculated with five H5N1 HPAI viruses. Virus titers in tissues cor...

  14. Development of a High Throughput Assay for Rapid and Accurate 10-Plex Detection of Citrus Pathogens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The need to reliably detect and identify multiple plant pathogens simultaneously, especially in woody perennial hosts, has led to development of new molecular diagnostic approaches. In this study, a Luminex-based system was developed that provided a robust and sensitive test for simultaneous detect...

  15. High-Mobility Holes in Dual-Gated WSe2 Field-Effect Transistors.

    PubMed

    Movva, Hema C P; Rai, Amritesh; Kang, Sangwoo; Kim, Kyounghwan; Fallahazad, Babak; Taniguchi, Takashi; Watanabe, Kenji; Tutuc, Emanuel; Banerjee, Sanjay K

    2015-10-27

    We demonstrate dual-gated p-type field-effect transistors (FETs) based on few-layer tungsten diselenide (WSe2) using high work-function platinum source/drain contacts and a hexagonal boron nitride top-gate dielectric. A device topology with contacts underneath the WSe2 results in p-FETs with ION/IOFF ratios exceeding 10(7) and contacts that remain ohmic down to cryogenic temperatures. The output characteristics show current saturation and gate tunable negative differential resistance. The devices show intrinsic hole mobilities around 140 cm(2)/(V s) at room temperature and approaching 4000 cm(2)/(V s) at 2 K. Temperature-dependent transport measurements show a metal-insulator transition, with an insulating phase at low densities and a metallic phase at high densities. The mobility shows a strong temperature dependence consistent with phonon scattering, and saturates at low temperatures, possibly limited by Coulomb scattering or defects. PMID:26343531

  16. Flexible cobalt-phthalocyanine thin films with high charge carrier mobility

    NASA Astrophysics Data System (ADS)

    Singh, Ajay; Kumar, Arvind; Kumar, Ashwini; Samanta, Soumen; Debnath, Anil K.; Jha, Purushottam; Prasad, Rajeshwar; Salmi, Zakaria; Nowak, Sophie; Chehimi, Mohamed M.; Aswal, Dinesh K.; Gupta, Shiv K.

    2012-11-01

    The structural and charge transport characteristics of cobalt phthalocyanine (CoPc) films deposited on flexible bi-axially oriented polyethylene terephthalate (BOPET) substrates are investigated. CoPc films exhibited a preferential (200) orientation with charge carrier mobility of ˜118 cm2 V-1 s-1 (at 300 K). These films exhibited a reversible resistance changes upon bending them to different radius of curvature. The charge transport in CoPc films is governed by a bias dependent crossover from ohmic (J-V) to trap-free space-charge limited conduction (J-V2). These results demonstrate that CoPc films on flexible BOPET having high mobility and high mechanical flexibility are a potential candidate for flexible electronic devices.

  17. Flexible cobalt-phthalocyanine thin films with high charge carrier mobility

    SciTech Connect

    Singh, Ajay; Kumar, Arvind; Kumar, Ashwini; Samanta, Soumen; Debnath, Anil K.; Jha, Purushottam; Prasad, Rajeshwar; Aswal, Dinesh K.; Gupta, Shiv K.; Salmi, Zakaria; Nowak, Sophie; Chehimi, Mohamed M.

    2012-11-26

    The structural and charge transport characteristics of cobalt phthalocyanine (CoPc) films deposited on flexible bi-axially oriented polyethylene terephthalate (BOPET) substrates are investigated. CoPc films exhibited a preferential (200) orientation with charge carrier mobility of {approx}118 cm{sup 2} V{sup -1} s{sup -1} (at 300 K). These films exhibited a reversible resistance changes upon bending them to different radius of curvature. The charge transport in CoPc films is governed by a bias dependent crossover from ohmic (J-V) to trap-free space-charge limited conduction (J-V{sup 2}). These results demonstrate that CoPc films on flexible BOPET having high mobility and high mechanical flexibility are a potential candidate for flexible electronic devices.

  18. Glycan:glycan interactions: High affinity biomolecular interactions that can mediate binding of pathogenic bacteria to host cells

    PubMed Central

    Day, Christopher J.; Tran, Elizabeth N.; Semchenko, Evgeny A.; Tram, Greg; Hartley-Tassell, Lauren E.; Ng, Preston S. K.; King, Rebecca M.; Ulanovsky, Rachel; McAtamney, Sarah; Apicella, Michael A.; Tiralongo, Joe; Morona, Renato; Korolik, Victoria; Jennings, Michael P.

    2015-01-01

    Cells from all domains of life express glycan structures attached to lipids and proteins on their surface, called glycoconjugates. Cell-to-cell contact mediated by glycan:glycan interactions have been considered to be low-affinity interactions that precede high-affinity protein–glycan or protein–protein interactions. In several pathogenic bacteria, truncation of surface glycans, lipooligosaccharide (LOS), or lipopolysaccharide (LPS) have been reported to significantly reduce bacterial adherence to host cells. Here, we show that the saccharide component of LOS/LPS have direct, high-affinity interactions with host glycans. Glycan microarrays reveal that LOS/LPS of four distinct bacterial pathogens bind to numerous host glycan structures. Surface plasmon resonance was used to determine the affinity of these interactions and revealed 66 high-affinity host–glycan:bacterial–glycan pairs with equilibrium dissociation constants (KD) ranging between 100 nM and 50 µM. These glycan:glycan affinity values are similar to those reported for lectins or antibodies with glycans. Cell assays demonstrated that glycan:glycan interaction-mediated bacterial adherence could be competitively inhibited by either host cell or bacterial glycans. This is the first report to our knowledge of high affinity glycan:glycan interactions between bacterial pathogens and the host. The discovery of large numbers of glycan:glycan interactions between a diverse range of structures suggests that these interactions may be important in all biological systems. PMID:26676578

  19. Glycan:glycan interactions: High affinity biomolecular interactions that can mediate binding of pathogenic bacteria to host cells.

    PubMed

    Day, Christopher J; Tran, Elizabeth N; Semchenko, Evgeny A; Tram, Greg; Hartley-Tassell, Lauren E; Ng, Preston S K; King, Rebecca M; Ulanovsky, Rachel; McAtamney, Sarah; Apicella, Michael A; Tiralongo, Joe; Morona, Renato; Korolik, Victoria; Jennings, Michael P

    2015-12-29

    Cells from all domains of life express glycan structures attached to lipids and proteins on their surface, called glycoconjugates. Cell-to-cell contact mediated by glycan:glycan interactions have been considered to be low-affinity interactions that precede high-affinity protein-glycan or protein-protein interactions. In several pathogenic bacteria, truncation of surface glycans, lipooligosaccharide (LOS), or lipopolysaccharide (LPS) have been reported to significantly reduce bacterial adherence to host cells. Here, we show that the saccharide component of LOS/LPS have direct, high-affinity interactions with host glycans. Glycan microarrays reveal that LOS/LPS of four distinct bacterial pathogens bind to numerous host glycan structures. Surface plasmon resonance was used to determine the affinity of these interactions and revealed 66 high-affinity host-glycan:bacterial-glycan pairs with equilibrium dissociation constants (K(D)) ranging between 100 nM and 50 µM. These glycan:glycan affinity values are similar to those reported for lectins or antibodies with glycans. Cell assays demonstrated that glycan:glycan interaction-mediated bacterial adherence could be competitively inhibited by either host cell or bacterial glycans. This is the first report to our knowledge of high affinity glycan:glycan interactions between bacterial pathogens and the host. The discovery of large numbers of glycan:glycan interactions between a diverse range of structures suggests that these interactions may be important in all biological systems. PMID:26676578

  20. A High Speed Mobile Courier Data Access System That Processes Database Queries in Real-Time

    NASA Astrophysics Data System (ADS)

    Gatsheni, Barnabas Ndlovu; Mabizela, Zwelakhe

    A secure high-speed query processing mobile courier data access (MCDA) system for a Courier Company has been developed. This system uses the wireless networks in combination with wired networks for updating a live database at the courier centre in real-time by an offsite worker (the Courier). The system is protected by VPN based on IPsec. There is no system that we know of to date that performs the task for the courier as proposed in this paper.

  1. A propagation experiment for modelling high elevation angle land mobile satellite channels

    NASA Technical Reports Server (NTRS)

    Richharia, M.; Evans, B. G.; Butt, G.

    1990-01-01

    This paper summarizes the results of a feasibility study for conducting high elevation angle propagation experiments in the European region for land mobile satellite communication. The study addresses various aspects of a proposed experiment. These include the selection of a suitable source for transmission, possibility of gathering narrow and wide band propagation data in various frequency bands, types of useful data, data acquisition technique, possible experimental configuration, and other experimental details.

  2. Interaction-induced huge magnetoresistance in a high mobility two-dimensional electron gas

    SciTech Connect

    Bockhorn, L.; Haug, R. J.; Gornyi, I. V.; Schuh, D.; Wegscheider, W.

    2013-12-04

    A strong negative magnetoresistance is observed in a high-mobility two-dimensional electron gas in a GaAs/Al{sub 0.3}Ga{sub 0.7}As quantum well. We discuss that the negative magnetoresistance consists of a small peak induced by a combination of two types of disorder and a huge magnetoresistance explained by the interaction correction to the conductivity for mixed disorder.

  3. Very Low Population Structure in a Highly Mobile and Wide-Ranging Endangered Bird Species

    PubMed Central

    Kvistad, Lynna; Ingwersen, Dean; Pavlova, Alexandra; Bull, James K.; Sunnucks, Paul

    2015-01-01

    The loss of biodiversity following fragmentation and degradation of habitat is a major issue in conservation biology. As competition for resources increases following habitat loss and fragmentation, severe population declines may occur even in common, highly mobile species; such demographic decline may cause changes within the population structure of the species. The regent honeyeater, Anthochaera phrygia, is a highly nomadic woodland bird once common in its native southeast Australia. It has experienced a sharp decline in abundance since the late 1970s, following clearing of large areas of its preferred habitat, box-ironbark woodland, within the last 200 years. A captive breeding program has been established as part of efforts to restore this species. This study used genetic data to examine the range-wide population structure of regent honeyeaters, including spatial structure, its change through time, sex differences in philopatry and mobility, and genetic differences between the captive and wild populations. There was low genetic differentiation between birds captured in different geographic areas. Despite the recent demographic decline, low spatial structure appears to have some temporal consistency. Both sexes appear to be highly mobile, and there does not seem to be significant genetic differentiation between the captive and wild populations. We conclude that management efforts for survival of this species, including habitat protection, restoration, and release of captive-bred birds into the wild, can treat the species as effectively a single genetic population. PMID:26649426

  4. Local imaging of high mobility two-dimensional electron systems with virtual scanning tunneling microscopy

    SciTech Connect

    Pelliccione, M.; Bartel, J.; Goldhaber-Gordon, D.; Sciambi, A.; Pfeiffer, L. N.; West, K. W.

    2014-11-03

    Correlated electron states in high mobility two-dimensional electron systems (2DESs), including charge density waves and microemulsion phases intermediate between a Fermi liquid and Wigner crystal, are predicted to exhibit complex local charge order. Existing experimental studies, however, have mainly probed these systems at micron to millimeter scales rather than directly mapping spatial organization. Scanning probes should be well-suited to study the spatial structure of these states, but high mobility 2DESs are found at buried semiconductor interfaces, beyond the reach of conventional scanning tunneling microscopy. Scanning techniques based on electrostatic coupling to the 2DES deliver important insights, but generally with resolution limited by the depth of the 2DES. In this letter, we present our progress in developing a technique called “virtual scanning tunneling microscopy” that allows local tunneling into a high mobility 2DES. Using a specially designed bilayer GaAs/AlGaAs heterostructure where the tunnel coupling between two separate 2DESs is tunable via electrostatic gating, combined with a scanning gate, we show that the local tunneling can be controlled with sub-250 nm resolution.

  5. Dietary Differentiation and the Evolution of Population Genetic Structure in a Highly Mobile Carnivore

    PubMed Central

    Pilot, Małgorzata; Jędrzejewski, Włodzimierz; Sidorovich, Vadim E.; Meier-Augenstein, Wolfram; Hoelzel, A. Rus

    2012-01-01

    Recent studies on highly mobile carnivores revealed cryptic population genetic structures correlated to transitions in habitat types and prey species composition. This led to the hypothesis that natal-habitat-biased dispersal may be responsible for generating population genetic structure. However, direct evidence for the concordant ecological and genetic differentiation between populations of highly mobile mammals is rare. To address this we analyzed stable isotope profiles (δ13C and δ15N values) for Eastern European wolves (Canis lupus) as a quantifiable proxy measure of diet for individuals that had been genotyped in an earlier study (showing cryptic genetic structure), to provide a quantitative assessment of the relationship between individual foraging behavior and genotype. We found a significant correlation between genetic distances and dietary differentiation (explaining 46% of the variation) in both the marginal test and crucially, when geographic distance was accounted for as a co-variable. These results, interpreted in the context of other possible mechanisms such as allopatry and isolation by distance, reinforce earlier studies suggesting that diet and associated habitat choice are influencing the structuring of populations in highly mobile carnivores. PMID:22768075

  6. Local imaging of high mobility two-dimensional electron systems with virtual scanning tunneling microscopy

    NASA Astrophysics Data System (ADS)

    Pelliccione, M.; Bartel, J.; Sciambi, A.; Pfeiffer, L. N.; West, K. W.; Goldhaber-Gordon, D.

    2014-11-01

    Correlated electron states in high mobility two-dimensional electron systems (2DESs), including charge density waves and microemulsion phases intermediate between a Fermi liquid and Wigner crystal, are predicted to exhibit complex local charge order. Existing experimental studies, however, have mainly probed these systems at micron to millimeter scales rather than directly mapping spatial organization. Scanning probes should be well-suited to study the spatial structure of these states, but high mobility 2DESs are found at buried semiconductor interfaces, beyond the reach of conventional scanning tunneling microscopy. Scanning techniques based on electrostatic coupling to the 2DES deliver important insights, but generally with resolution limited by the depth of the 2DES. In this letter, we present our progress in developing a technique called "virtual scanning tunneling microscopy" that allows local tunneling into a high mobility 2DES. Using a specially designed bilayer GaAs/AlGaAs heterostructure where the tunnel coupling between two separate 2DESs is tunable via electrostatic gating, combined with a scanning gate, we show that the local tunneling can be controlled with sub-250 nm resolution.

  7. Dietary differentiation and the evolution of population genetic structure in a highly mobile carnivore.

    PubMed

    Pilot, Małgorzata; Jędrzejewski, Włodzimierz; Sidorovich, Vadim E; Meier-Augenstein, Wolfram; Hoelzel, A Rus

    2012-01-01

    Recent studies on highly mobile carnivores revealed cryptic population genetic structures correlated to transitions in habitat types and prey species composition. This led to the hypothesis that natal-habitat-biased dispersal may be responsible for generating population genetic structure. However, direct evidence for the concordant ecological and genetic differentiation between populations of highly mobile mammals is rare. To address this we analyzed stable isotope profiles (δ(13)C and δ(15)N values) for Eastern European wolves (Canis lupus) as a quantifiable proxy measure of diet for individuals that had been genotyped in an earlier study (showing cryptic genetic structure), to provide a quantitative assessment of the relationship between individual foraging behavior and genotype. We found a significant correlation between genetic distances and dietary differentiation (explaining 46% of the variation) in both the marginal test and crucially, when geographic distance was accounted for as a co-variable. These results, interpreted in the context of other possible mechanisms such as allopatry and isolation by distance, reinforce earlier studies suggesting that diet and associated habitat choice are influencing the structuring of populations in highly mobile carnivores. PMID:22768075

  8. Very Low Population Structure in a Highly Mobile and Wide-Ranging Endangered Bird Species.

    PubMed

    Kvistad, Lynna; Ingwersen, Dean; Pavlova, Alexandra; Bull, James K; Sunnucks, Paul

    2015-01-01

    The loss of biodiversity following fragmentation and degradation of habitat is a major issue in conservation biology. As competition for resources increases following habitat loss and fragmentation, severe population declines may occur even in common, highly mobile species; such demographic decline may cause changes within the population structure of the species. The regent honeyeater, Anthochaera phrygia, is a highly nomadic woodland bird once common in its native southeast Australia. It has experienced a sharp decline in abundance since the late 1970s, following clearing of large areas of its preferred habitat, box-ironbark woodland, within the last 200 years. A captive breeding program has been established as part of efforts to restore this species. This study used genetic data to examine the range-wide population structure of regent honeyeaters, including spatial structure, its change through time, sex differences in philopatry and mobility, and genetic differences between the captive and wild populations. There was low genetic differentiation between birds captured in different geographic areas. Despite the recent demographic decline, low spatial structure appears to have some temporal consistency. Both sexes appear to be highly mobile, and there does not seem to be significant genetic differentiation between the captive and wild populations. We conclude that management efforts for survival of this species, including habitat protection, restoration, and release of captive-bred birds into the wild, can treat the species as effectively a single genetic population. PMID:26649426

  9. Novel Highly Pathogenic Avian H5 Influenza A Viruses in Live Poultry Markets, Wuxi City, China, 2013−2014

    PubMed Central

    Ma, Mai-Juan; Chen, Shan-Hui; Wang, Guo-Lin; Zhao, Teng; Qian, Yan-Hua; Wu, Meng-Na; Liu, Ying; Gray, Gregory C.; Lu, Bing; Cao, Wu-Chun

    2016-01-01

    During 12 recent months of periodic influenza virus surveillance at 9 live poultry markets in Wuxi City China, we identified multiple highly pathogenic H5N6, H5N8, H5N2, and H5N1 avian influenza viruses. The variety of potentially pandemic viruses in this low-risk area is disconcerting and portends an increased pandemic threat. PMID:27186580

  10. Surveillance for Highly Pathogenic Avian Influenza Virus in Wild Birds during Outbreaks in Domestic Poultry, Minnesota, 2015

    PubMed Central

    Carstensen, Michelle; Hildebrand, Erik C.; Cornicelli, Louis; Wolf, Paul; Grear, Daniel A.; Ip, Hon S.; Vandalen, Kaci K.; Minicucci, Larissa A.

    2016-01-01

    In 2015, a major outbreak of highly pathogenic avian influenza virus (HPAIV) infection devastated poultry facilities in Minnesota, USA. To understand the potential role of wild birds, we tested 3,139 waterfowl fecal samples and 104 sick and dead birds during March 9–June 4, 2015. HPAIV was isolated from a Cooper’s hawk but not from waterfowl fecal samples. PMID:27064759

  11. Highly pathogenic influenza H5N1 virus of clade 2.3.2.1c in Western Siberia.

    PubMed

    Marchenko, V Y; Susloparov, I M; Kolosova, N P; Goncharova, N I; Shipovalov, A V; Ilyicheva, T N; Durymanov, A G; Chernyshova, O A; Kozlovskiy, L I; Chernyshova, T V; Pryadkina, E N; Karimova, T V; Mikheev, V N; Ryzhikov, A B

    2016-06-01

    In the spring of 2015, avian influenza virus surveillance in Western Siberia resulted in isolation of several influenza H5N1 virus strains. The strains were isolated from several wild bird species. Investigation of biological features of those strains demonstrated their high pathogenicity for mammals. Phylogenetic analysis of the HA gene showed that the strains belong to clade 2.3.2.1c. PMID:26935914

  12. Impact ionization in N-polar AlGaN/GaN high electron mobility transistors

    SciTech Connect

    Killat, N. E-mail: Martin.Kuball@bristol.ac.uk; Uren, M. J.; Kuball, M. E-mail: Martin.Kuball@bristol.ac.uk; Keller, S.; Kolluri, S.; Mishra, U. K.

    2014-08-11

    The existence of impact ionization as one of the open questions for GaN device reliability was studied in N-polar AlGaN/GaN high electron mobility transistors. Electroluminescence (EL) imaging and spectroscopy from underneath the device gate contact revealed the presence of hot electrons in excess of the GaN bandgap energy even at moderate on-state bias conditions, enabling impact ionization with hole currents up to several hundreds of pA/mm. The detection of high energy luminescence from hot electrons demonstrates that EL analysis is a highly sensitive tool to study degradation mechanisms in GaN devices.

  13. High-throughput magnetic flow sorting of human cells selected on the basis of magnetophoretic mobility

    NASA Astrophysics Data System (ADS)

    Reece, Lisa M.; Sanders, Lehanna; Kennedy, David; Guernsey, Byron; Todd, Paul; Leary, James F.

    2010-02-01

    We have shown the potential of a new method for optimizing the separation of human stem cell subsets from peripheral blood based on a novel cell labeling technique that leverages the capabilities of a new commercially available high speed magnetic cell sorting system (IKOTECH LLC, New Albany, IN). This new system sorts cells in a continuously flowing manner using a Quadrupole Magnetic cell Sorter (QMS). The sorting mechanism is based upon the magnetophoretic mobility of the cells, a property related to the relative binding distributions of magnetic particles per cell, as determined by the utilization of a Magnetic Cell Tracking Velocimeter (MCTV). KG-1 cells were competitively labeled with anti-CD34 magnetic beads and anti-CD34 FITC to obtain an optimal level of magnetophoretic mobility as visualized by the MCTV for high throughput sort recovery in the QMS. In QMS sorting, the concept of split-flow thin channel (SPLITT) separation technology is applied by having a sample stream enter a vertical annular flow channel near the channel's interior wall followed by another sheath flow entering near the exterior wall. The two flows are initially separated by a flow splitter. They pass through the bore of a Halbach permanent quadrupole magnet assembly, which draws magnetized cells outward and deflects them into a positive outflow, while negative cells continue straight out via the inner flow lamina. QMS sorts cells based upon their magnetophoretic mobility, or the velocity of a cell per unit ponderomotive force, the counterpart of fluorescence intensity in flow cytometry. The magnetophoretic mobility distribution of a cell population, measured by automated MCTV, is used as input data for the algorithmic control of sample, sheath, and outlet flow velocities of the QMS. In this study, the relative binding distributions of magnetic particles per cell were determined by MCTV using novel sorting and sizing algorithms. The resulting mobility histograms were used to set the QMS

  14. High-Risk Enteric Pathogens Associated with HIV-Infection and HIV-Exposure in Kenyan Children with Acute Diarrhea

    PubMed Central

    PAVLINAC, PB; JOHN-STEWART, GC; NAULIKHA, JM; ONCHIRI, FM; DENNO, DM; ODUNDO, EA; SINGA, BO; RICHARDSON, BA; WALSON, JL

    2015-01-01

    Objective HIV-infection is an established risk for diarrheal severity, less is known about specific enteric pathogens associated with HIV status. We determined associations of selected enteric pathogens with HIV-infection and HIV-exposure among Kenyan children. Design Cross-sectional study among 6 months to 15 year olds presenting to two Western Kenya District hospitals with acute diarrhea between 2011–2013. Methods Stool was tested using standard bacterial culture and microscopy for ova and parasites. HIV testing was obtained on children and mothers. Enteric pathogen prevalence was compared between HIV-infected and HIV-uninfected children and between HIV-exposed uninfected (HEU) and HIV-unexposed. Unadjusted and adjusted prevalence ratios (PR) for selected pathogens by HIV-status were estimated using relative risk (RR) regression and P-values. Age, site, income, household crowding, water source/treatment, anthropometrics, cotrimoxazole use, and breastfeeding history were accounted for in multivariable models. Results Among 1,076 children, median age was 22 months (interquartile range: 11–42), 56 (5.2%) were HIV-infected, and 10.3%(105/1020) of HIV-uninfected children were HIV-exposed. The following organisms were most frequently isolated from stool: enteroaggregative Escherichia coli (13.3%), Giardia spp. (11.1%) Campylobacter (6.3%), enteropathogenic Escherichia coli (EPEC) (6.1%) and Cryptosporidium spp. (3.7%). Accounting for age, HIV-infection was associated with EPEC infection (PR: 3.70, P=0.002) while HIV-exposure was associated with Cryptosporidium among HIV-uninfected children (PR: 2.81, P=0.005). Conclusion EPEC and Cryptosporidium infections were more common in HIV-infected and HIV-exposed children, respectively. This could explain the increased mortality attributed to these pathogens in other studies. Interventions targeting EPEC and Cryptosporidium may reduce morbidity and mortality in high HIV-prevalence settings. PMID:25028987

  15. Very high channel conductivity in low-defect AlN/GaN high electron mobility transistor structures

    SciTech Connect

    Dabiran, A. M.; Wowchak, A. M.; Osinsky, A.; Xie, J.; Hertog, B.; Cui, B.; Chow, P. P.; Look, D. C.

    2008-08-25

    Low defect AlN/GaN high electron mobility transistor (HEMT) structures, with very high values of electron mobility (>1800 cm{sup 2}/V s) and sheet charge density (>3x10{sup 13} cm{sup -2}), were grown by rf plasma-assisted molecular beam epitaxy (MBE) on sapphire and SiC, resulting in sheet resistivity values down to {approx}100 {omega}/{open_square} at room temperature. Fabricated 1.2 {mu}m gate devices showed excellent current-voltage characteristics, including a zero gate saturation current density of {approx}1.3 A/mm and a peak transconductance of {approx}260 mS/mm. Here, an all MBE growth of optimized AlN/GaN HEMT structures plus the results of thin-film characterizations and device measurements are presented.

  16. Ecological Determinants of Highly Pathogenic Avian Influenza (H5N1) Outbreaks in Bangladesh

    PubMed Central

    Ahmed, Syed S. U.; Ersbøll, Annette K.; Biswas, Paritosh K.; Christensen, Jens P.; Hannan, Abu S. M. A.; Toft, Nils

    2012-01-01

    Background The agro-ecology and poultry husbandry of the south Asian and south-east Asian countries share common features, however, with noticeable differences. Hence, the ecological determinants associated with risk of highly pathogenic avian influenza (HPAI-H5N1) outbreaks are expected to differ between Bangladesh and e.g., Thailand and Vietnam. The primary aim of the current study was to establish ecological determinants associated with the risk of HPAI-H5N1 outbreaks at subdistrict level in Bangladesh. The secondary aim was to explore the performance of two different statistical modeling approaches for unmeasured spatially correlated variation. Methodology/Principal Findings An ecological study at subdistrict level in Bangladesh was performed with 138 subdistricts with HPAI-H5N1 outbreaks during 2007–2008, and 326 subdistricts with no outbreaks. The association between ecological determinants and HPAI-H5N1 outbreaks was examined using a generalized linear mixed model. Spatial clustering of the ecological data was modeled using 1) an intrinsic conditional autoregressive (ICAR) model at subdistrict level considering their first order neighbors, and 2) a multilevel (ML) model with subdistricts nested within districts. Ecological determinants significantly associated with risk of HPAI-H5N1 outbreaks at subdistrict level were migratory birds' staging areas, river network, household density, literacy rate, poultry density, live bird markets, and highway network. Predictive risk maps were derived based on the resulting models. The resulting models indicate that the ML model absorbed some of the covariate effect of the ICAR model because of the neighbor structure implied in the two different models. Conclusions/Significance The study identified a new set of ecological determinants related to river networks, migratory birds' staging areas and literacy rate in addition to already known risk factors, and clarified that the generalized concept of free grazing duck and

  17. The Influence of Perceived Convenience and Curiosity on Continuance Intention in Mobile English Learning for High School Students Using PDAs

    ERIC Educational Resources Information Center

    Chang, Chi-Cheng; Tseng, Kuo-Hung; Liang, Chaoyun; Yan, Chi-Fang

    2013-01-01

    Mobile learning aims to utilise communication devices such as mobile devices and wireless connection in combination with e-learning systems, allowing learners to experience convenient, instant and suitable learning at unrestricted time and place. Participants were 125 Taiwanese senior high school students, whose continuance intention was examined…

  18. Chinese and Vietnamese strains of HP-PRRSV cause different pathogenic outcomes in United States high health swine.

    PubMed

    Guo, Baoqing; Lager, Kelly M; Schlink, Sarah N; Kehrli, Marcus E; Brockmeier, Susan L; Miller, Laura C; Swenson, Sabrina L; Faaberg, Kay S

    2013-11-01

    An infectious clone of a highly pathogenic PRRSV strain from Vietnam (rSRV07) was prepared and was demonstrated to contain multiple amino acid differences throughout the genome when compared to Chinese highly pathogenic PRRSV strain rJXwn06. Virus rescued from the rSRV07 infectious clone was compared to rJXwn06 and US Type 2 prototype strain VR-2332 to examine the effects of virus genotype and phenotype on in vitro growth, and virus challenge dose on in vivo pathogenicity and host response. After swine inoculation at high- and low-doses of virus, rSRV07 was shown to replicate to an approximately 10-fold lower level in serum than rJXwn06, produced lower body temperatures than rJXwn06 and resulted in decreased mortality. Furthermore, a 9-plex cytokine panel revealed that the cytokine responses varied between different strains of PRRSV, as well as between tissues examined and by inoculum dose. PMID:24074587

  19. High-Throughput Screening of Myometrial Calcium-Mobilization to Identify Modulators of Uterine Contractility

    PubMed Central

    Herington, Jennifer L.; Swale, Daniel R.; Brown, Naoko; Shelton, Elaine L.; Choi, Hyehun; Williams, Charles H.; Hong, Charles C.; Paria, Bibhash C.; Denton, Jerod S.; Reese, Jeff

    2015-01-01

    The uterine myometrium (UT-myo) is a therapeutic target for preterm labor, labor induction, and postpartum hemorrhage. Stimulation of intracellular Ca2+-release in UT-myo cells by oxytocin is a final pathway controlling myometrial contractions. The goal of this study was to develop a dual-addition assay for high-throughput screening of small molecular compounds, which could regulate Ca2+-mobilization in UT-myo cells, and hence, myometrial contractions. Primary murine UT-myo cells in 384-well plates were loaded with a Ca2+-sensitive fluorescent probe, and then screened for inducers of Ca2+-mobilization and inhibitors of oxytocin-induced Ca2+-mobilization. The assay exhibited robust screening statistics (Z´ = 0.73), DMSO-tolerance, and was validated for high-throughput screening against 2,727 small molecules from the Spectrum, NIH Clinical I and II collections of well-annotated compounds. The screen revealed a hit-rate of 1.80% for agonist and 1.39% for antagonist compounds. Concentration-dependent responses of hit-compounds demonstrated an EC50 less than 10μM for 21 hit-antagonist compounds, compared to only 7 hit-agonist compounds. Subsequent studies focused on hit-antagonist compounds. Based on the percent inhibition and functional annotation analyses, we selected 4 confirmed hit-antagonist compounds (benzbromarone, dipyridamole, fenoterol hydrobromide and nisoldipine) for further analysis. Using an ex vivo isometric contractility assay, each compound significantly inhibited uterine contractility, at different potencies (IC50). Overall, these results demonstrate for the first time that high-throughput small-molecules screening of myometrial Ca2+-mobilization is an ideal primary approach for discovering modulators of uterine contractility. PMID:26600013

  20. Promiscuous Pathogenicity Islands and Phylogeny of Pathogenic Streptomyces spp.

    PubMed

    Zhang, Yucheng; Bignell, Dawn R D; Zuo, Ran; Fan, Qiurong; Huguet-Tapia, Jose C; Ding, Yousong; Loria, Rosemary

    2016-08-01

    Approximately 10 Streptomyces species cause disease on underground plant structures. The most economically important of these is potato scab, and the most studied of these pathogens is Streptomyces scabiei (syn. S. scabies). The main pathogenicity determinant of scab-causing Streptomyces species is a nitrated diketopiperazine, known as thaxtomin A (ThxA). In the pathogenic species Streptomyces turgidiscabies, ThxA biosynthetic genes reside on a mobile pathogenicity island (PAI). However, the mobilization of PAIs in other Streptomyces species remains uncharacterized. Here, we investigated the mobilization of the PAI of S. scabiei 87-22. Based on whole genome sequences, we inferred the evolutionary relationships of pathogenic Streptomyces species and discovered that Streptomyces sp. strain 96-12, a novel pathogenic species isolated from potatoes in Egypt, was phylogenetically grouped with nonpathogenic species rather than with known pathogenic species. We also found that Streptomyces sp. strain 96-12 contains a PAI that is almost identical to the PAI in S. scabiei 87-22, despite significant differences in their genome sequences. This suggested direct or indirect in vivo mobilization of the PAI between S. scabiei and nonpathogenic Streptomyces species. To test whether the S. scabiei 87-22 PAI could, indeed, be mobilized, S. scabiei 87-22 deletion mutants containing antibiotic resistance markers in the PAI were mated with Streptomyces diastatochromogenes, a nonpathogenic species. The PAI of S. scabiei was site-specifically inserted into the aviX1 gene of S. diastatochromogenes and conferred pathogenicity in radish seedling assays. Our results demonstrated that S. scabiei, the earliest described Streptomyces pathogen, could be the source of a PAI responsible for the emergence of novel pathogenic species. PMID:27502745

  1. High-quality complete genome sequence of Microbacterium sp. SUBG005, a plant pathogen

    PubMed Central

    Rakhashiya, Purvi M.; Patel, Pooja P.; Thaker, Vrinda S.

    2015-01-01

    Microbacterium sp. SUBG005 is a Gram positive bacterium, isolated from infected leaf of Mangifera indica L. in Rajkot (22.30°N, 70.78°E), Gujarat, India. The genome sequencing of Microbacterium sp. SUBG005 is having type I secretion system genes of pathogenicity as well as heavy metal resistance unique genes. The genome size is 7.01 Mb with G + C content of 64.80% and contains rRNA sequences. Genome sequencing analysis provides information about the microbe role in host–pathogen interaction. The whole genome sequencing has been deposited in DDBJ/EMBL/GenBank under the accession number JNNT00000000. PMID:26484276

  2. Transmutation of Personal Glucose Meters into Portable and Highly Sensitive Microbial Pathogen Detection Platform.

    PubMed

    Wang, Zhenzhen; Chen, Zhaowei; Gao, Nan; Ren, Jinsong; Qu, Xiaogang

    2015-10-01

    Herein, for the first time, we presented a simple and general approach by using personal glucose meters (PGM) for portable and ultrasensitive detection of microbial pathogens. Upon addition of pathogenic bacteria, glucoamylase-quaternized magnetic nanoparticles (GA-QMNPS) conjugates were disrupted by the competitive multivalent interactions between bacteria and QMNPS, resulting in the release of GA. After magnetic separation, the free GA could catalyze the hydrolysis of amylose into glucose for quantitative readout by PGM. In such way, PGM was transmuted into a bacterial detection device and extremely low detection limits down to 20 cells mL(-1) was achieved. More importantly, QMNPS could inhibit the growth of the bacteria and destroy its cellular structure, which enabled bacteria detection and inhibition simultaneously. The simplicity, portability, sensitivity and low cost of presented work make it attractive for clinical applications. PMID:26153225

  3. Fully Solution-Processed Flexible Organic Thin Film Transistor Arrays with High Mobility and Exceptional Uniformity

    PubMed Central

    Fukuda, Kenjiro; Takeda, Yasunori; Mizukami, Makoto; Kumaki, Daisuke; Tokito, Shizuo

    2014-01-01

    Printing fully solution-processed organic electronic devices may potentially revolutionize production of flexible electronics for various applications. However, difficulties in forming thin, flat, uniform films through printing techniques have been responsible for poor device performance and low yields. Here, we report on fully solution-processed organic thin-film transistor (TFT) arrays with greatly improved performance and yields, achieved by layering solution-processable materials such as silver nanoparticle inks, organic semiconductors, and insulating polymers on thin plastic films. A treatment layer improves carrier injection between the source/drain electrodes and the semiconducting layer and dramatically reduces contact resistance. Furthermore, an organic semiconductor with large-crystal grains results in TFT devices with shorter channel lengths and higher field-effect mobilities. We obtained mobilities of over 1.2 cm2 V−1 s−1 in TFT devices with channel lengths shorter than 20 μm. By combining these fabrication techniques, we built highly uniform organic TFT arrays with average mobility levels as high as 0.80 cm2 V−1 s−1 and ideal threshold voltages of 0 V. These results represent major progress in the fabrication of fully solution-processed organic TFT device arrays. PMID:24492785

  4. Coherent Terahertz Magneto-Spectroscopy of High-Mobility Two-Dimensional Electron Gases

    NASA Astrophysics Data System (ADS)

    Zhang, Qi; Arikawa, Takashi; Pan, Wei; Reno, John; Watson, John; Manfra, Michael; Kono, Junichiro; Rice University Team; Sandia National Laboratory Collaboration; Purdue University Collaboration

    2013-03-01

    Landau-quantized high-mobility two-dimensional electron gases (2DEG) in GaAs quantum wells provide an ideal platform for studying and controlling the coherence of many-electron states. Here, we study the coherent dynamics of cyclotron resonance (CR) in a 2DEGin the terahertz range. It is well known that Kohn's theorem protects the CR frequency from the influence of electron-electron interactions, but how the coherence of CR decays via electron-electron interactions is an open question. Since the 1980s, studies have focused on CR decoherence time measurements, primarily using incoherent far-infrared spectroscopy, which fails to obtain the true CR linewidth due to the `saturation effect' in high-mobility systems. By using coherent time-domain magneto-terahertz spectroscopy, we have systematically studied the CR decoherence time in an ultrahigh-mobility 2DEG as a function of both temperature and magnetic field. These results show a clear saturation of the CR decoherence time at low temperature, which decreases monotonically with increasing magnetic field. No filling-factor-dependent oscillations of CR dephasing time have been observed. Possible CR decoherence mechanisms will be discussed in light of these new findings.

  5. Combining ion mobility spectrometry, mass spectrometry, and photoelectron spectroscopy in a high-transmission instrument.

    PubMed

    Vonderach, Matthias; Ehrler, Oli T; Weis, Patrick; Kappes, Manfred M

    2011-02-01

    We have developed a novel instrument that combines ion mobility spectrometry, mass spectro-metry, and photoelectron spectroscopy. The instrument couples an electrospray ion source, a high-transmission ion mobility cell based on ion funnels, a quadrupole mass filter, and a time-of-flight (magnetic bottle) photoelectron spectrometer operated with a pulsed detachment laser. We show that the instrument can resolve highly structured anion arrival time distributions and at the same time provide corresponding photoelectron spectra-using the DNA oligonucleotide ion [dC(6) - 5H](5-) as a test case. For this multianion we find at least four different, noninterconverting isomers (conformers) simultaneously present in the gas phase at room temperature. For each of these we record well-resolved and remarkably different photoelectron spectra at each of three different detachment laser wavelengths. Two-dimensional ion mobility/electron binding energy plots can be acquired with an automated data collection procedure. We expect that this kind of instrument will significantly improve the capabilities for structure determination of (bio)molecular anions in the gas phase. PMID:21214198

  6. Mechanical flip-chip for ultra-high electron mobility devices

    DOE PAGESBeta

    Bennaceur, Keyan; Schmidt, Benjamin A.; Gaucher, Samuel; Laroche, Dominique; Sandia National Lab.; Lilly, Michael P.; Reno, John L.; West, Ken W.; Pfeiffer, Loren N.; Gervais, Guillaume

    2015-09-22

    In this study, electrostatic gates are of paramount importance for the physics of devices based on high-mobility two-dimensional electron gas (2DEG) since they allow depletion of electrons in selected areas. This field-effect gating enables the fabrication of a wide range of devices such as, for example, quantum point contacts (QPC), electron interferometers and quantum dots. To fabricate these gates, processing is usually performed on the 2DEG material, which is in many cases detrimental to its electron mobility. Here we propose an alternative process which does not require any processing of the 2DEG material other than for the ohmic contacts. Thismore » approach relies on processing a separate wafer that is then mechanically mounted on the 2DEG material in a flip-chip fashion. This technique proved successful to fabricate quantum point contacts on both GaAs/AlGaAs materials with both moderate and ultra-high electron mobility.« less

  7. Plasma-Assisted Synthesis of High-Mobility Atomically Layered Violet Phosphorus.

    PubMed

    Tsai, Hsu-Sheng; Lai, Chih-Chung; Hsiao, Ching-Hung; Medina, Henry; Su, Teng-Yu; Ouyang, Hao; Chen, Tai-Hsiang; Liang, Jenq-Horng; Chueh, Yu-Lun

    2015-07-01

    Two-dimensional layered materials such as graphene, transition metal dichalcogenides, and black phosphorus have demonstrated outstanding properties due to electron confinement as the thickness is reduced to atomic scale. Among the phosphorus allotropes, black phosphorus, and violet phosphorus possess layer structure with the potential to be scaled down to atomically thin film. For the first time, the plasma-assisted synthesis of atomically layered violet phosphorus has been achieved. Material characterization supports the formation of violet phosphorus/InN over InP substrate where the layer structure of violet phosphorus is clearly observed. The identification of the crystal structure and lattice constant ratifies the formation of violet phosphorus indeed. The critical concept of this synthesis method is the selective reaction induced by different variations of Gibbs free energy (ΔG) of reactions. Besides, the Hall mobility of the violet phosphorus on the InP substrate greatly increases over the theoretical values of InP bulk material without much reduction in the carrier concentration, suggesting that the mobility enhancement results from the violet phosphorus layers. Furthermore, this study demonstrates a low-cost technique with high compatibility to synthesize the high-mobility atomically layered violet phosphorus and open the space for the study of the fundamental properties of this intriguing material as a new member of the fast growing family of 2D crystals. PMID:26070035

  8. Effects of inositol trisphosphate on calcium mobilization in high-voltage and saponin-permeabilized platelets

    SciTech Connect

    Gear, A.R.L.; Hallam, T.J.

    1986-03-01

    Interest in phosphatidylinositol metabolism has been greatly stimulated by the findings that diglyceride and inositol phosphates may serve as second messengers in modulating cellular function. Formation of 1,4,5-inositol trisphosphate (IP/sub 3/), in particular, has been linked to mobilization of intracellular calcium in a number of cell types. The authors have examined the ability of IP/sub 3/ to mobilize calcium in human platelets permeabilized by either saponin or high-voltage discharge. Saponin at 15 ..mu..g/ml effectively permeabilized platelets to exogenous inositol 1,4,5-trisphosphate which released bound (/sup 45/Ca) within 1 min and with a Ka of 7.4 +/- 4.1 ..mu..M. A small (25%) azide-sensitive pool was also responsive to inositol trisphosphate. The calcium pools were completely discharged by A-23187 and the ATP-dependent uptake was prevented by dinitrophenol. In contrast to the result with saponin, platelets accessed by high-voltage discharge were insensitive to challenge by inositol 1,4,5-trisphosphate. The data suggest that while inositol 1,4,5-trisphosphate can rapidly mobilize platelet calcium, the ability to demonstrate this depends on the method of permeabilization.

  9. Fully Solution-Processed Flexible Organic Thin Film Transistor Arrays with High Mobility and Exceptional Uniformity

    NASA Astrophysics Data System (ADS)

    Fukuda, Kenjiro; Takeda, Yasunori; Mizukami, Makoto; Kumaki, Daisuke; Tokito, Shizuo

    2014-02-01

    Printing fully solution-processed organic electronic devices may potentially revolutionize production of flexible electronics for various applications. However, difficulties in forming thin, flat, uniform films through printing techniques have been responsible for poor device performance and low yields. Here, we report on fully solution-processed organic thin-film transistor (TFT) arrays with greatly improved performance and yields, achieved by layering solution-processable materials such as silver nanoparticle inks, organic semiconductors, and insulating polymers on thin plastic films. A treatment layer improves carrier injection between the source/drain electrodes and the semiconducting layer and dramatically reduces contact resistance. Furthermore, an organic semiconductor with large-crystal grains results in TFT devices with shorter channel lengths and higher field-effect mobilities. We obtained mobilities of over 1.2 cm2 V-1 s-1 in TFT devices with channel lengths shorter than 20 μm. By combining these fabrication techniques, we built highly uniform organic TFT arrays with average mobility levels as high as 0.80 cm2 V-1 s-1 and ideal threshold voltages of 0 V. These results represent major progress in the fabrication of fully solution-processed organic TFT device arrays.

  10. Significant mobility enhancement in extremely thin highly doped ZnO films

    SciTech Connect

    Look, David C.; Heller, Eric R.; Yao, Yu-Feng; Yang, C. C.

    2015-04-13

    Highly Ga-doped ZnO (GZO) films of thicknesses d = 5, 25, 50, and 300 nm, grown on 160-nm ZnO buffer layers by molecular beam epitaxy, had 294-K Hall-effect mobilities μ{sub H} of 64.1, 43.4, 37.0, and 34.2 cm{sup 2}/V-s, respectively. This extremely unusual ordering of μ{sub H} vs d is explained by the existence of a very high-mobility Debye tail in the ZnO, arising from the large Fermi-level mismatch between the GZO and the ZnO. Scattering theory in conjunction with Poisson analysis predicts a Debye-tail mobility of 206 cm{sup 2}/V-s at the interface (z = d), falling to 58 cm{sup 2}/V-s at z = d + 2 nm. Excellent fits to μ{sub H} vs d and sheet concentration n{sub s} vs d are obtained with no adjustable parameters.

  11. Excitation of coupled ion lattice-streaming carrier modes in high mobility semiconductors

    SciTech Connect

    Riyopoulos, S.

    2009-03-15

    Interaction between streaming carrier plasmons and lattice vibrations in ultrahigh mobility materials generates novel, hybrid, lattice-streaming carrier modes. The Boltzmann kinetic equation for a collisionless carrier response is employed to obtain a dispersion relation including the effects of thermal velocity spreads. The resulting slow electrostatic (ES) modes involve plasmon-phonon (PP) coupling, while the fast electromagnetic (EM) modes involve plasmon-photon-phonon coupling. There is an unstable parameter regime leading to spontaneous growth of slow ES PP modes from noise. Thermal spreads reduce but do not eliminate the growth rate. The fast EM modes are found to be stable and slightly damped over the parameter regime. Spontaneous growth of ES modes carries implications for terahertz generation in high mobility materials.

  12. High-mobility bio-organic field effect transistors with photoreactive DNAs as gate insulators

    NASA Astrophysics Data System (ADS)

    Kim, Youn Sun; Jung, Ki Hwa; Lee, U. Ra; Kim, Kyung Hwan; Hoang, Mai Ha; Jin, Jung-Il; Choi, Dong Hoon

    2010-03-01

    Organic-soluble DNAs bearing chalcone moieties were synthesized by using purified natural sodium DNA. In addition to the chalcone-containing DNA homopolymer (CcDNA), a copolymer (CTMADNA-co-CcDNA) was synthesized. They were employed as gate insulators for fabricating organic thin-film transistors. An organic semiconductor (5,5'-(9,10-bis((4-hexylphenyl)ethynyl)anthracene-2,6-yl-diyl)bis(ethyne-2,1-diyl)bis(2-hexylthiophene; HB-ant-THT) was deposited on the photocrosslinked DNA-based gate insulators via a solution process. Interestingly, the resulting TFT devices had extremely high field-effect mobilities, and their corresponding transfer curves indicated low hysteresis. The carrier mobility of the device with HB-ant-THT deposited on the CTMADNA-co-CcDNA gate insulator was the best, i.e., 0.31 cm2 V-1 s-1 (Ion/Ioff=1.0×104).

  13. Electrophoretic Mobility of a Dilute, Highly Charged "Soft" Spherical Particle in a Charged Hydrogel.

    PubMed

    Allison, Stuart; Li, Fei; Le, Melinda

    2016-08-25

    In this paper, numerical modeling studies are carried out on the electrophoretic mobility of a dilute, highly charged "soft" spherical particle in a hard hydrogel subjected to a weak, constant, external electric field. The particle contains a solid core with either a uniform charge density or "zeta" potential on its surface. Outside of this lies a charged gel layer of uniform thickness, composition, and charge density. The present work extends previous studies by accounting for the "relaxation effect", or distortion of the charge distribution in the vicinity of the model particle due to the imposition of an external electric and/or flow field. The particle gel layer and ambient hydrogel are modeled as porous Brinkman media. The (steady state) electrodynamic problem is solved at the level of the Poisson equation. Applications emphasize the influence of the relaxation effect and hydrogel charge density on the electrophoretic mobility. PMID:26815300

  14. Structured back gates for high-mobility two-dimensional electron systems using oxygen ion implantation

    NASA Astrophysics Data System (ADS)

    Berl, M.; Tiemann, L.; Dietsche, W.; Karl, H.; Wegscheider, W.

    2016-03-01

    We present a reliable method to obtain patterned back gates compatible with high mobility molecular beam epitaxy via local oxygen ion implantation that suppresses the conductivity of an 80 nm thick silicon doped GaAs epilayer. Our technique was optimized to circumvent several constraints of other gating and implantation methods. The ion-implanted surface remains atomically flat which allows unperturbed epitaxial overgrowth. We demonstrate the practical application of this gating technique by using magneto-transport spectroscopy on a two-dimensional electron system (2DES) with a mobility exceeding 20 × 106 cm2/V s. The back gate was spatially separated from the Ohmic contacts of the 2DES, thus minimizing the probability for electrical shorts or leakage and permitting simple contacting schemes.

  15. Expression of H5 hemagglutinin vaccine antigen in common duckweed (Lemna minor) protects against H5N1 high pathogenicity avian influenza virus challenge in immunized chickens

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A synthetic hemagglutinin (HA) gene from the highly pathogenic avian influenza (HPAI) virus A/chicken/Indonesia/7/2003 (H5N1) (Indo/03) was expressed in aquatic plant Lemna minor (rLemna-HA). In Experiment 1, efficacy of rLemna-HA was tested on specific pathogen free (SPF) birds immunized with 0.2 ...

  16. Analysis of the swine tracheobronchial lymphnode transcriptomic response to infection with a Chinese highly pathogenic strain of porcine reproductive and respiratory syndrome virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Porcine reproductive and respiratory syndrome virus (PRRSV) is a major pathogen of swine worldwide. Emergence in 2006 of a novel highly pathogenic PRRSV (HP-PRRSV) isolate in China necessitated a comparative investigation into the host transcriptome response in tracheobronchial lymph nod...

  17. Effect of age on pathogenesis and innate immune responses in Pekin ducks infected with different H5N1 highly pathogenic avian influenza viruses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The pathogenicity of H5N1 highly pathogenic avian influenza (HPAI) viruses in domestic ducks varies between different viruses and is affected by the age of the ducks, with younger ducks presenting more severe disease. In order to better understand the pathobiology of H5N1 HPAI in ducks, including t...

  18. The influence of economic indicators, poultry density and the performance of Veterinary Services on the control of high-pathogenicity avian influenza in poultry

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High pathogenicity avian influenza (HPAI) and low pathogenicity notifiable avian influenza (LPNAI) in poultry are notifiable to World Organisation for Animal Health (OIE) by its member countries. There may be variation between countries’ responses to avian influenza (AI) outbreak situations based o...

  19. Analysis of the swine tracheobronchial lymphnode transcriptomic response to infection with a Chinese highly pathogenic strain of porcine reproductive and respiratory syndrome virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Porcine reproductive and respiratory syndrome virus (PRRSV) is a major pathogen of swine worldwide. Emergence in 2006 of a novel highly pathogenic PRRSV (HP-PRRSV) isolate in China necessitated a comparative investigation into the host transcriptome response in tracheobronchial lymph nodes (TBLN) 14...

  20. Swine tracheobronchial lymph node mRNA responses in swine infected with a highly pathogenic strain of porcine reproductive and respiratory syndrome virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Porcine reproductive and respiratory syndrome virus (PRRSV) is a major pathogen of swine worldwide. Emergence in 2006 of a novel highly pathogenic PRRSV (HP-PRRSV) isolate in China necessitated a comparative investigation into the host transcriptome response in tracheobronchial lymph nodes (TBLN) 14...

  1. Pathobiological Characterization of a Novel Reassortant Highly Pathogenic H5N1 Virus Isolated in British Columbia, Canada, 2015.

    PubMed

    Berhane, Yohannes; Kobasa, Darwyn; Embury-Hyatt, Carissa; Pickering, Brad; Babiuk, Shawn; Joseph, Tomy; Bowes, Victoria; Suderman, Mathew; Leung, Anders; Cottam-Birt, Colleen; Hisanaga, Tamiko; Pasick, John

    2016-01-01

    In the current study, we describe the pathobiologic characteristics of a novel reassortant virus - A/chicken/BC/FAV-002/2015 (H5N1) belonging to clade 2.3.4.4 that was isolated from backyard chickens in British Columbia, Canada. Sequence analyses demonstrate PB1, PA, NA and NS gene segments were of North American lineage while PB2, HA, NP and M were derived from a Eurasian lineage H5N8 virus. This novel virus had a 19 amino acid deletion in the neuraminidase stalk. We evaluated the pathogenic potential of this isolate in various animal models. The virus was highly pathogenic to mice with a LD50 of 10 plaque forming units (PFU), but had limited tissue tropism. It caused only subclinical infection in pigs which did result in seroconversion. This virus was highly pathogenic to chickens, turkeys, juvenile Muscovy ducks (Cairnia moschata foma domestica) and adult Chinese geese (Anser cynoides domesticus) causing a systemic infection in all species. The virus was also efficiently transmitted and resulted in mortality in naïve contact ducks, geese and chickens. Our findings indicate that this novel H5N1 virus has a wide host range and enhanced surveillance of migratory waterfowl may be necessary in order to determine its potential to establish itself in the wild bird reservoir. PMID:26988892

  2. Pathobiological Characterization of a Novel Reassortant Highly Pathogenic H5N1 Virus Isolated in British Columbia, Canada, 2015

    PubMed Central

    Berhane, Yohannes; Kobasa, Darwyn; Embury-Hyatt, Carissa; Pickering, Brad; Babiuk, Shawn; Joseph, Tomy; Bowes, Victoria; Suderman, Mathew; Leung, Anders; Cottam-Birt, Colleen; Hisanaga, Tamiko; Pasick, John

    2016-01-01

    In the current study, we describe the pathobiologic characteristics of a novel reassortant virus - A/chicken/BC/FAV-002/2015 (H5N1) belonging to clade 2.3.4.4 that was isolated from backyard chickens in British Columbia, Canada. Sequence analyses demonstrate PB1, PA, NA and NS gene segments were of North American lineage while PB2, HA, NP and M were derived from a Eurasian lineage H5N8 virus. This novel virus had a 19 amino acid deletion in the neuraminidase stalk. We evaluated the pathogenic potential of this isolate in various animal models. The virus was highly pathogenic to mice with a LD50 of 10 plaque forming units (PFU), but had limited tissue tropism. It caused only subclinical infection in pigs which did result in seroconversion. This virus was highly pathogenic to chickens, turkeys, juvenile Muscovy ducks (Cairnia moschata foma domestica) and adult Chinese geese (Anser cynoides domesticus) causing a systemic infection in all species. The virus was also efficiently transmitted and resulted in mortality in naïve contact ducks, geese and chickens. Our findings indicate that this novel H5N1 virus has a wide host range and enhanced surveillance of migratory waterfowl may be necessary in order to determine its potential to establish itself in the wild bird reservoir. PMID:26988892

  3. The operation cutoff frequency of high electron mobility transistor measured by terahertz method

    SciTech Connect

    Zhu, Y. M. Zhuang, S. L.

    2014-07-07

    Commonly, the cutoff frequency of high electron mobility transistor (HEMT) can be measured by vector network analyzer (VNA), which can only measure the sample exactly in low frequency region. In this paper, we propose a method to evaluate the cutoff frequency of HEMT by terahertz (THz) technique. One example shows the cutoff frequency of our HEMT is measured at ∼95.30 GHz, which is reasonable agreement with that estimated by VNA. It is proved THz technology a potential candidate for the substitution of VNA for the measurement of high-speed devices even up to several THz.

  4. Application of high-performance steel in mobile hydraulic cranes and aerial work platforms

    SciTech Connect

    Pike, G.S.

    1995-12-31

    The market for mobile hydraulic cranes and aerial work platforms is highly competitive and customers continue to demand increased lift capacity and heights with decreased cost and vehicle weight. As Grove designers strive to optimize these parameters, the Materials and Welding Engineering Department must provide them with materials that surpass the capabilities of materials covered by established industry standards such as ASTM. These industry standards, due to their consensus nature, do not keep pace with the latest steel-making technology, which is often proprietary in nature. Therefore, Grove works with suppliers to support development of high performance steels by providing performance goals, fabrication testing, and a market for these new materials.

  5. Construction of Fe3O4/Vancomycin/PEG Magnetic Nanocarrier for Highly Efficient Pathogen Enrichment and Gene Sensing.

    PubMed

    Zhu, Minjun; Liu, Weipeng; Liu, Hongxing; Liao, Yuhui; Wei, Jitao; Zhou, Xiaoming; Xing, Da

    2015-06-17

    Infectious diseases, especially pathogenic bacterial infections, pose a growing threat to public health worldwide. As pathogenic bacteria usually exist in complex experimental matrixes at very low concentrations, developing a technology for rapid and biocompatible sample enrichment is essential for sensitive diagnosis. In this study, an Fe3O4/Vancomycin/PEG magnetic nanocarrier was constructed for efficient sample enrichment and in situ nucleic acid preparation of pathogenic bacteria for subsequent gene sensing. We attached Vancomycin, a well-known broad-spectrum antibiotic, to the surface of Fe3O4 nanoparticles as a universal molecular probe to target bacterial cells. Polyethylene glycol (PEG) was introduced to enhance the nanocarrier's water solubility and biocompatibility. Results show that the proposed nanocarrier achieved a 90% capture efficiency even if at a Listeria monocytogenes concentration of 1×10(2) cfu/mL. Contributing to the good water solubility achieved by the employment of modified PEG, highly efficient enrichment (enrichment factor 10 times higher than PEG-free nanocarrier) can be completed in 30 min. Moreover, PEG would also develop the nanoparticles' biocompatibility by passivating the positively charged unreacted amines on the magnetic nanoparticles, thus helping to release the negatively charged bacterial genome from the nanocarrier/bacteria complexes when an in situ nucleic acids extraction step was executed. The outstanding bacterial capture capability and biocompatibility of this nanocarrier enabled the implementation of a highly sensitive gene-sensing strategy of pathogens. By employing an electrochemiluminescence-based gene-sensing assay, L. monocytogenes can be rapidly detected with a limit of detection of 10 cfu/mL, which shows great potential for clinical applications. PMID:26005899

  6. A High Diversity of Eurasian Lineage Low Pathogenicity Avian Influenza A Viruses Circulate among Wild Birds Sampled in Egypt

    PubMed Central

    Gerloff, Nancy A.; Jones, Joyce; Simpson, Natosha; Balish, Amanda; ElBadry, Maha Adel; Baghat, Verina; Rusev, Ivan; de Mattos, Cecilia C.; de Mattos, Carlos A.; Zonkle, Luay Elsayed Ahmed; Kis, Zoltan; Davis, C. Todd; Yingst, Sam; Cornelius, Claire; Soliman, Atef; Mohareb, Emad; Klimov, Alexander; Donis, Ruben O.

    2013-01-01

    Surveillance for influenza A viruses in wild birds has increased substantially as part of efforts to control the global movement of highly pathogenic avian influenza A (H5N1) virus. Studies conducted in Egypt from 2003 to 2007 to monitor birds for H5N1 identified multiple subtypes of low pathogenicity avian influenza A viruses isolated primarily from migratory waterfowl collected in the Nile Delta. Phylogenetic analysis of 28 viral genomes was performed to estimate their nearest ancestors and identify possible reassortants. Migratory flyway patterns were included in the analysis to assess gene flow between overlapping flyways. Overall, the viruses were most closely related to Eurasian, African and/or Central Asian lineage low pathogenicity viruses and belonged to 15 different subtypes. A subset of the internal genes seemed to originate from specific flyways (Black Sea-Mediterranean, East African-West Asian). The remaining genes were derived from a mixture of viruses broadly distributed across as many as 4 different flyways suggesting the importance of the Nile Delta for virus dispersal. Molecular clock date estimates suggested that the time to the nearest common ancestor of all viruses analyzed ranged from 5 to 10 years, indicating frequent genetic exchange with viruses sampled elsewhere. The intersection of multiple migratory bird flyways and the resulting diversity of influenza virus gene lineages in the Nile Delta create conditions favoring reassortment, as evident from the gene constellations identified by this study. In conclusion, we present for the first time a comprehensive phylogenetic analysis of full genome sequences from low pathogenic avian influenza viruses circulating in Egypt, underscoring the significance of the region for viral reassortment and the potential emergence of novel avian influenza A viruses, as well as representing a highly diverse influenza A virus gene pool that merits continued monitoring. PMID:23874653

  7. High-throughput detection of food-borne pathogenic bacteria using oligonucleotide microarray with quantum dots as fluorescent labels.

    PubMed

    Huang, Aihua; Qiu, Zhigang; Jin, Min; Shen, Zhiqiang; Chen, Zhaoli; Wang, Xinwei; Li, Jun-Wen

    2014-08-18

    Bacterial pathogens are mostly responsible for food-borne diseases, and there is still substantial room for improvement in the effective detection of these organisms. In the present study, we explored a new method to detect target pathogens easily and rapidly with high sensitivity and specificity. This method uses an oligonucleotide microarray combined with quantum dots as fluorescent labels. Oligonucleotide probes targeting the 16SrRNA gene were synthesized to create an oligonucleotide microarray. The PCR products labeled with biotin were subsequently hybridized using an oligonucleotide microarray. Following incubation with CdSe/ZnS quantum dots coated with streptavidin, fluorescent signals were detected with a PerkinElmer Gx Microarray Scanner. The results clearly showed specific hybridization profiles corresponding to the bacterial species assessed. Two hundred and sixteen strains of food-borne bacterial pathogens, including standard strains and isolated strains from food samples, were used to test the specificity, stability, and sensitivity of the microarray system. We found that the oligonucleotide microarray combined with quantum dots used as fluorescent labels can successfully discriminate the bacterial organisms at the genera or species level, with high specificity and stability as well as a sensitivity of 10 colony forming units (CFU)/mL of pure culture. We further tested 105 mock-contaminated food samples and achieved consistent results as those obtained from traditional biochemical methods. Together, these results indicate that the quantum dot-based oligonucleotide microarray has the potential to be a powerful tool in the detection and identification of pathogenic bacteria in foods. PMID:24927399

  8. Anxiety in high-functioning autism: A pilot study of experience sampling using a mobile platform.

    PubMed

    Hare, Dougal Julian; Gracey, Carolyn; Wood, Christopher

    2016-08-01

    Anxiety and stress are everyday issues for many people with high-functioning autism, and while cognitive-behavioural therapy is the treatment of choice for the management of anxiety, there are challenges in using it with people with high-functioning autism. This study used modified experience sampling techniques to examine everyday anxiety and stress in adults with high-functioning autism and to explore the feasibility of delivering real-time stress management techniques using a mobile platform. High levels of anxiety were found to be characterised by worry, confusing thoughts and being alone but was not associated with internal focus, imagery or rumination. Participants reported improved mood and less worry and anxious thinking in the active phase of the study. These results support previous studies indicating that people with high-functioning autism differ in their experience of anxiety and provided preliminary data on the feasibility of real-time stress management. The limitations of this approach are discussed together with considerations for future work in the area of developing clinical interventions on mobile platforms. PMID:26514793

  9. Towards high charge-carrier mobilities by rational design of the shape and periphery of discotics.

    PubMed

    Feng, Xinliang; Marcon, Valentina; Pisula, Wojciech; Hansen, Michael Ryan; Kirkpatrick, James; Grozema, Ferdinand; Andrienko, Denis; Kremer, Kurt; Müllen, Klaus

    2009-05-01

    Discotic liquid crystals are a promising class of materials for molecular electronics thanks to their self-organization and charge transporting properties. The best discotics so far are built around the coronene unit and possess six-fold symmetry. In the discotic phase six-fold-symmetric molecules stack with an average twist of 30 degrees, whereas the angle that would lead to the greatest electronic coupling is 60 degrees. Here, a molecule with three-fold symmetry and alternating hydrophilic/hydrophobic side chains is synthesized and X-ray scattering is used to prove the formation of the desired helical microstructure. Time-resolved microwave-conductivity measurements show that the material has indeed a very high mobility, 0.2 cm(2) V(-1) s(-1). The assemblies of molecules are simulated using molecular dynamics, confirming the model deduced from X-ray scattering. The simulated structures, together with quantum-chemical techniques, prove that mobility is still limited by structural defects and that a defect-free assembly could lead to mobilities in excess of 10 cm(2) V(-1) s(-1). PMID:19363476

  10. High-mobility capacitively-induced two-dimensional electrons in a lateral superlattice potential

    DOE PAGESBeta

    Lu, Tzu -Ming; Laroche, Dominique; Huang, S. -H.; Chuang, Y.; Li, J. -Y.; Liu, C. W.

    2016-01-01

    In the presence of a lateral periodic potential modulation, two-dimensional electrons may exhibit interesting phenomena, such as a graphene-like energy-momentum dispersion, Bloch oscillations, or the Hofstadter butterfly band structure. To create a sufficiently strong potential modulation using conventional semiconductor heterostructures, aggressive device processing is often required, unfortunately resulting in strong disorder that masks the sought-after effects. Here, we report a novel fabrication process flow for imposing a strong lateral potential modulation onto a capacitively induced two-dimensional electron system, while preserving the host material quality. Using this process flow, the electron density in a patterned Si/SiGe heterostructure can be tuned overmore » a wide range, from 4.4 × 1010 cm–2 to 1.8 × 1011 cm–2, with a peak mobility of 6.4 × 105 cm2/V·s. The wide density tunability and high electron mobility allow us to observe sequential emergence of commensurability oscillations as the density, the mobility, and in turn the mean free path, increase. Magnetic-field-periodic quantum oscillations associated with various closed orbits also emerge sequentially with increasing density. We show that, from the density dependence of the quantum oscillations, one can directly extract the steepness of the imposed superlattice potential. Lastly, this result is then compared to a conventional lateral superlattice model potential.« less

  11. High-mobility capacitively-induced two-dimensional electrons in a lateral superlattice potential

    NASA Astrophysics Data System (ADS)

    Lu, T. M.; Laroche, D.; Huang, S.-H.; Chuang, Y.; Li, J.-Y.; Liu, C. W.

    2016-02-01

    In the presence of a lateral periodic potential modulation, two-dimensional electrons may exhibit interesting phenomena, such as a graphene-like energy-momentum dispersion, Bloch oscillations, or the Hofstadter butterfly band structure. To create a sufficiently strong potential modulation using conventional semiconductor heterostructures, aggressive device processing is often required, unfortunately resulting in strong disorder that masks the sought-after effects. Here, we report a novel fabrication process flow for imposing a strong lateral potential modulation onto a capacitively induced two-dimensional electron system, while preserving the host material quality. Using this process flow, the electron density in a patterned Si/SiGe heterostructure can be tuned over a wide range, from 4.4 × 1010 cm-2 to 1.8 × 1011 cm-2, with a peak mobility of 6.4 × 105 cm2/V·s. The wide density tunability and high electron mobility allow us to observe sequential emergence of commensurability oscillations as the density, the mobility, and in turn the mean free path, increase. Magnetic-field-periodic quantum oscillations associated with various closed orbits also emerge sequentially with increasing density. We show that, from the density dependence of the quantum oscillations, one can directly extract the steepness of the imposed superlattice potential. This result is then compared to a conventional lateral superlattice model potential.

  12. High-mobility capacitively-induced two-dimensional electrons in a lateral superlattice potential

    SciTech Connect

    Lu, Tzu -Ming; Laroche, Dominique; Huang, S. -H.; Chuang, Y.; Li, J. -Y.; Liu, C. W.

    2016-01-01

    In the presence of a lateral periodic potential modulation, two-dimensional electrons may exhibit interesting phenomena, such as a graphene-like energy-momentum dispersion, Bloch oscillations, or the Hofstadter butterfly band structure. To create a sufficiently strong potential modulation using conventional semiconductor heterostructures, aggressive device processing is often required, unfortunately resulting in strong disorder that masks the sought-after effects. Here, we report a novel fabrication process flow for imposing a strong lateral potential modulation onto a capacitively induced two-dimensional electron system, while preserving the host material quality. Using this process flow, the electron density in a patterned Si/SiGe heterostructure can be tuned over a wide range, from 4.4 × 1010 cm–2 to 1.8 × 1011 cm–2, with a peak mobility of 6.4 × 105 cm2/V·s. The wide density tunability and high electron mobility allow us to observe sequential emergence of commensurability oscillations as the density, the mobility, and in turn the mean free path, increase. Magnetic-field-periodic quantum oscillations associated with various closed orbits also emerge sequentially with increasing density. We show that, from the density dependence of the quantum oscillations, one can directly extract the steepness of the imposed superlattice potential. Lastly, this result is then compared to a conventional lateral superlattice model potential.

  13. High-mobility capacitively-induced two-dimensional electrons in a lateral superlattice potential

    PubMed Central

    Lu, T. M.; Laroche, D.; Huang, S.-H.; Chuang, Y.; Li, J.-Y.; Liu, C. W.

    2016-01-01

    In the presence of a lateral periodic potential modulation, two-dimensional electrons may exhibit interesting phenomena, such as a graphene-like energy-momentum dispersion, Bloch oscillations, or the Hofstadter butterfly band structure. To create a sufficiently strong potential modulation using conventional semiconductor heterostructures, aggressive device processing is often required, unfortunately resulting in strong disorder that masks the sought-after effects. Here, we report a novel fabrication process flow for imposing a strong lateral potential modulation onto a capacitively induced two-dimensional electron system, while preserving the host material quality. Using this process flow, the electron density in a patterned Si/SiGe heterostructure can be tuned over a wide range, from 4.4 × 1010 cm−2 to 1.8 × 1011 cm−2, with a peak mobility of 6.4 × 105 cm2/V·s. The wide density tunability and high electron mobility allow us to observe sequential emergence of commensurability oscillations as the density, the mobility, and in turn the mean free path, increase. Magnetic-field-periodic quantum oscillations associated with various closed orbits also emerge sequentially with increasing density. We show that, from the density dependence of the quantum oscillations, one can directly extract the steepness of the imposed superlattice potential. This result is then compared to a conventional lateral superlattice model potential. PMID:26865160

  14. Pushing the Frontier of High-Definition Ion Mobility Spectrometry Using FAIMS

    PubMed Central

    A. Shvartsburg, Alexandre; A. Anderson, Gordon; D. Smith, Richard

    2013-01-01

    Differential ion mobility spectrometry (FAIMS) separates ions in gases based on the difference between their mobilities in strong and weak electric fields, captured directly employing a periodic waveform with dissimilar profiles in opposite polarities. As that difference is not tightly correlated with the ion size or mass, FAIMS separations are generally quite orthogonal to both conventional IMS (based on the absolute ion mobility that reflects the physical ion size) and mass spectrometry (based on mass). Until a few years ago, that advantage was largely offset by poor FAIMS resolving power (∼10–20), an order of magnitude below that achieved with conventional (drift-tube) IMS. This article summarizes the major recent technical developments that have raised FAIMS resolving power up to ∼500. These include use of higher and more stable voltages provided by new waveform generators, novel buffer gas compositions comprising high helium or hydrogen fractions, and extended filtering times up to ∼1 s. These advances have enabled previously unthinkable analyses such as broad baseline separations of peptide sequence inversions, localization variants (post-translationally modified peptides with differing PTM attachment sites) even for the larger “middle-down” peptides and smallest PTMs, and lipid regioisomers. PMID:24349930

  15. Ultra-low noise high electron mobility transistors for high-impedance and low-frequency deep cryogenic readout electronics

    SciTech Connect

    Dong, Q.; Liang, Y. X.; Ferry, D.; Cavanna, A.; Gennser, U.; Couraud, L.; Jin, Y.

    2014-07-07

    We report on the results obtained from specially designed high electron mobility transistors at 4.2 K: the gate leakage current can be limited lower than 1 aA, and the equivalent input noise-voltage and noise-current at 1 Hz can reach 6.3 nV/Hz{sup 1∕2} and 20 aA/Hz{sup 1∕2}, respectively. These results open the way to realize high performance low-frequency readout electronics under very low-temperature conditions.

  16. Ultra-low noise high electron mobility transistors for high-impedance and low-frequency deep cryogenic readout electronics

    NASA Astrophysics Data System (ADS)

    Dong, Q.; Liang, Y. X.; Ferry, D.; Cavanna, A.; Gennser, U.; Couraud, L.; Jin, Y.

    2014-07-01

    We report on the results obtained from specially designed high electron mobility transistors at 4.2 K: the gate leakage current can be limited lower than 1 aA, and the equivalent input noise-voltage and noise-current at 1 Hz can reach 6.3 nV/Hz1/2 and 20 aA/Hz1/2, respectively. These results open the way to realize high performance low-frequency readout electronics under very low-temperature conditions.

  17. High-Mobility Transistors Based on Large-Area and Highly Crystalline CVD-Grown MoSe2 Films on Insulating Substrates.

    PubMed

    Rhyee, Jong-Soo; Kwon, Junyeon; Dak, Piyush; Kim, Jin Hee; Kim, Seung Min; Park, Jozeph; Hong, Young Ki; Song, Won Geun; Omkaram, Inturu; Alam, Muhammad A; Kim, Sunkook

    2016-03-01

    Large-area and highly crystalline CVD-grown multilayer MoSe2 films exhibit a well-defined crystal structure (2H phase) and large grains reaching several hundred micrometers. Multilayer MoSe2 transistors exhibit high mobility up to 121 cm(2) V(-1) s(-1) and excellent mechanical stability. These results suggest that high mobility materials will be indispensable for various future applications such as high-resolution displays and human-centric soft electronics. PMID:26755196

  18. Determining the Phylogenetic and Phylogeographic Origin of Highly Pathogenic Avian Influenza (H7N3) in Mexico

    PubMed Central

    Lu, Lu; Lycett, Samantha J.; Leigh Brown, Andrew J.

    2014-01-01

    Highly pathogenic (HP) avian influenza virus (AIV) H7N3 outbreaks occurred 3 times in the Americas in the past 10 years and caused severe economic loss in the affected regions. In June/July 2012, new HP H7N3 outbreaks occurred at commercial farms in Jalisco, Mexico. Outbreaks continued to be identified in neighbouring states in Mexico till August 2013. To explore the origin of this outbreak, time resolved phylogenetic trees were generated from the eight segments of full-length AIV sequences in North America using BEAST. Location, subtype, avian host species and pathogenicity were modelled as discrete traits upon the trees using continuous time Markov chains. A further joint analysis among segments was performed using a hierarchical phylogenetic model (HPM) which allowed trait rates (location, subtype, host species) to be jointly inferred across different segments. The complete spatial diffusion process was visualised through virtual globe software. Our result indicated the Mexico HP H7N3 originated from the large North America low pathogenicity AIV pool through complicated reassortment events. Different segments were contributed by wild waterfowl from different N. American flyways. Five of the eight segments (HA, NA, NP, M, NS) were introduced from wild birds migrating along the central North American flyway, and PB2, PB1 and PA were introduced via the western North American flyway. These results highlight a potential role for Mexico as a hotspot of virus reassortment as it is where wild birds from different migration routes mix during the winter. PMID:25226523

  19. Promising electron mobility and high thermal conductivity in Sc2CT2 (T = F, OH) MXenes.

    PubMed

    Zha, Xian-Hu; Zhou, Jie; Zhou, Yuhong; Huang, Qing; He, Jian; Francisco, Joseph S; Luo, Kan; Du, Shiyu

    2016-03-10

    MXenes, the new 2D transition metal carbides and nitrides, have recently attracted extensive attention due to their diverse applications and excellent performances. However, the thermal and electrical properties of most MXene materials are yet to be studied. In this work, we investigate the electrical and thermal properties of semiconducting Sc2CT2 (T = F, OH) MXenes using first-principles calculations. Both of the Sc2CT2 (T = F, OH) MXenes are determined to show excellent carrier mobilities. The electron mobility in the Sc2CF2 MXene is found to be strongly anisotropic at room temperature, with values of 5.03 × 10(3) and 1.07 × 10(3) cm(2) V(-1) s(-1) in the zigzag and armchair directions, respectively. The predicted electron mobility in the zigzag direction of the Sc2CF2 is nearly four-fold that in the armchair direction of the promising semiconductor phosphorene. In contrast to Sc2CF2, Sc2C(OH)2 presents approximately isotropic electron mobility. The values at room temperature in the zigzag and armchair directions are calculated as 2.06 × 10(3) cm(2) V(-1) s(-1) and 2.19 × 10(3) cm(2) V(-1) s(-1), respectively. In regard to the thermal properties, the thermal conductivities of the Sc2CT2 (T = F, OH) MXenes have been determined. The predicted values are higher than those of most metals and semiconducting low-dimensional materials, such as monolayer MoS2 and phosphorene. In particular, the room-temperature thermal conductivity along the Sc2CF2 armchair direction has been determined to be as high as 472 W m(-1) K(-1) based on a flake length of 5 μm, which is even higher than that of the best traditional conductor silver. The corresponding value in the zigzag direction of Sc2CF2 is calculated to be 178 W m(-1) K(-1). The thermal conductivity in Sc2C(OH)2 is less anisotropic and lower compared to that in Sc2CF2. The room-temperature value in the armchair (zigzag) direction is determined to be 173 W m(-1) K(-1) (107 W m(-1) K(-1)). Based on their excellent

  20. RNA Sequencing Reveals Differences between the Global Transcriptomes of Salmonella enterica Serovar Enteritidis Strains with High and Low Pathogenicities

    PubMed Central

    2014-01-01

    Salmonella enterica serovar Enteritidis is one of the important causes of bacterial food-borne gastroenteritis worldwide. Field strains of S. Enteritidis are relatively genetically homogeneous; however, they show extensive phenotypic diversity and differences in virulence potential. RNA sequencing (RNA-Seq) was used to characterize differences in the global transcriptome between several genetically similar but phenotypically diverse poultry-associated field strains of S. Enteritidis grown in laboratory medium at avian body temperature (42°C). These S. Enteritidis strains were previously characterized as high-pathogenicity (HP; n = 3) and low-pathogenicity (LP; n = 3) strains based on both in vitro and in vivo virulence assays. Using the negative binomial distribution-based statistical tools edgeR and DESeq, 252 genes were identified as differentially expressed in LP strains compared with their expression in the HP strains (P < 0.05). A majority of genes (235, or 93.2%) showed significantly reduced expression, whereas a few genes (17, or 6.8%) showed increased expression in all LP strains compared with HP strains. LP strains showed a unique transcriptional profile that is characterized by significantly reduced expression of several transcriptional regulators and reduced expression of genes involved in virulence (e.g., Salmonella pathogenicity island 1 [SPI-1], SPI-5, and fimbrial and motility genes) and protection against osmotic, oxidative, and other stresses, such as iron-limiting conditions commonly encountered within the host. Several functionally uncharacterized genes also showed reduced expression. This study provides a first concise view of the global transcriptional differences between field strains of S. Enteritidis with various levels of pathogenicity, providing the basis for future functional characterization of several genes with potential roles in virulence or stress regulation of S. Enteritidis. PMID:24271167

  1. Balance the Carrier Mobility To Achieve High Performance Exciplex OLED Using a Triazine-Based Acceptor.

    PubMed

    Hung, Wen-Yi; Chiang, Pin-Yi; Lin, Shih-Wei; Tang, Wei-Chieh; Chen, Yi-Ting; Liu, Shih-Hung; Chou, Pi-Tai; Hung, Yi-Tzu; Wong, Ken-Tsung

    2016-02-01

    A star-shaped 1,3,5-triazine/cyano hybrid molecule CN-T2T was designed and synthesized as a new electron acceptor for efficient exciplex-based OLED emitter by mixing with a suitable electron donor (Tris-PCz). The CN-T2T/Tris-PCz exciplex emission shows a high ΦPL of 0.53 and a small ΔET-S = -0.59 kcal/mol, affording intrinsically efficient fluorescence and highly efficient exciton up-conversion. The large energy level offsets between Tris-PCz and CN-T2T and the balanced hole and electron mobility of Tris-PCz and CN-T2T, respectively, ensuring sufficient carrier density accumulated in the interface for efficient generation of exciplex excitons. Employing a facile device structure composed as ITO/4% ReO3:Tris-PCz (60 nm)/Tris-PCz (15 nm)/Tris-PCz:CN-T2T(1:1) (25 nm)/CN-T2T (50 nm)/Liq (0.5 nm)/Al (100 nm), in which the electron-hole capture is efficient without additional carrier injection barrier from donor (or acceptor) molecule and carriers mobilities are balanced in the emitting layer, leads to a highly efficient green exciplex OLED with external quantum efficiency (EQE) of 11.9%. The obtained EQE is 18% higher than that of a comparison device using an exciplex exhibiting a comparable ΦPL (0.50), in which TCTA shows similar energy levels but higher hole mobility as compared with Tris-PCz. Our results clearly indicate the significance of mobility balance in governing the efficiency of exciplex-based OLED. Exploiting the Tris-PCz:CN-T2T exciplex as the host, we further demonstrated highly efficient yellow and red fluorescent OLEDs by doping 1 wt % Rubrene and DCJTB as emitter, achieving high EQE of 6.9 and 9.7%, respectively. PMID:26820247

  2. High mobility AlGaN/GaN devices for β--dosimetry

    NASA Astrophysics Data System (ADS)

    Schmid, Martin; Howgate, John; Ruehm, Werner; Thalhammer, Stefan

    2016-05-01

    There is a high demand in modern medical applications for dosimetry sensors with a small footprint allowing for unobtrusive or high spatial resolution detectors. To this end we characterize the sensoric response of radiation resistant high mobility AlGaN/GaN semiconductor devices when exposed to β--emitters. The samples were operated as a floating gate transistor, without a field effect gate electrode, thus excluding any spurious effects from β--particle interactions with a metallic surface covering. We demonstrate that the source-drain current is modulated in dependence on the kinetic energy of the incident β--particles. Here, the signal is shown to have a linear dependence on the absorbed energy calculated from Monte Carlo simulations. Additionally, a stable and reproducible sensor performance as a β--dose monitor is shown for individual radioisotopes. Our experimental findings and the characteristics of the AlGaN/GaN high mobility layered devices indicate their potential for future applications where small sensor size is necessary, like for instance brachytherapy.

  3. Protective immunity against H7N3 highly pathogenic avian influenza induced following inoculation of chickens with H7 low pathogenic avian influenza virus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In the poultry industry, live virus vaccines are used to induce immunity against numerous respiratory pathogens. These are typically lower virulent forms of virus which are limited in replication and pathology, but induce mucosal, humoral, and cellular immunity. Because of the potential for revers...

  4. Promising electron mobility and high thermal conductivity in Sc2CT2 (T = F, OH) MXenes

    NASA Astrophysics Data System (ADS)

    Zha, Xian-Hu; Zhou, Jie; Zhou, Yuhong; Huang, Qing; He, Jian; Francisco, Joseph S.; Luo, Kan; Du, Shiyu

    2016-03-01

    MXenes, the new 2D transition metal carbides and nitrides, have recently attracted extensive attention due to their diverse applications and excellent performances. However, the thermal and electrical properties of most MXene materials are yet to be studied. In this work, we investigate the electrical and thermal properties of semiconducting Sc2CT2 (T = F, OH) MXenes using first-principles calculations. Both of the Sc2CT2 (T = F, OH) MXenes are determined to show excellent carrier mobilities. The electron mobility in the Sc2CF2 MXene is found to be strongly anisotropic at room temperature, with values of 5.03 × 103 and 1.07 × 103 cm2 V-1 s-1 in the zigzag and armchair directions, respectively. The predicted electron mobility in the zigzag direction of the Sc2CF2 is nearly four-fold that in the armchair direction of the promising semiconductor phosphorene. In contrast to Sc2CF2, Sc2C(OH)2 presents approximately isotropic electron mobility. The values at room temperature in the zigzag and armchair directions are calculated as 2.06 × 103 cm2 V-1 s-1 and 2.19 × 103 cm2 V-1 s-1, respectively. In regard to the thermal properties, the thermal conductivities of the Sc2CT2 (T = F, OH) MXenes have been determined. The predicted values are higher than those of most metals and semiconducting low-dimensional materials, such as monolayer MoS2 and phosphorene. In particular, the room-temperature thermal conductivity along the Sc2CF2 armchair direction has been determined to be as high as 472 W m-1 K-1 based on a flake length of 5 μm, which is even higher than that of the best traditional conductor silver. The corresponding value in the zigzag direction of Sc2CF2 is calculated to be 178 W m-1 K-1. The thermal conductivity in Sc2C(OH)2 is less anisotropic and lower compared to that in Sc2CF2. The room-temperature value in the armchair (zigzag) direction is determined to be 173 W m-1 K-1 (107 W m-1 K-1). Based on their excellent electron mobilities and high thermal

  5. Induced superconductivity in high-mobility two-dimensional electron gas in gallium arsenide heterostructures.

    PubMed

    Wan, Zhong; Kazakov, Aleksandr; Manfra, Michael J; Pfeiffer, Loren N; West, Ken W; Rokhinson, Leonid P

    2015-01-01

    Search for Majorana fermions renewed interest in semiconductor-superconductor interfaces, while a quest for higher-order non-Abelian excitations demands formation of superconducting contacts to materials with fractionalized excitations, such as a two-dimensional electron gas in a fractional quantum Hall regime. Here we report induced superconductivity in high-mobility two-dimensional electron gas in gallium arsenide heterostructures and development of highly transparent semiconductor-superconductor ohmic contacts. Supercurrent with characteristic temperature dependence of a ballistic junction has been observed across 0.6 μm, a regime previously achieved only in point contacts but essential to the formation of well separated non-Abelian states. High critical fields (>16 T) in NbN contacts enables investigation of an interplay between superconductivity and strongly correlated states in a two-dimensional electron gas at high magnetic fields. PMID:26067452

  6. Induced superconductivity in high-mobility two-dimensional electron gas in gallium arsenide heterostructures

    NASA Astrophysics Data System (ADS)

    Wan, Zhong; Kazakov, Aleksandr; Manfra, Michael J.; Pfeiffer, Loren N.; West, Ken W.; Rokhinson, Leonid P.

    2015-06-01

    Search for Majorana fermions renewed interest in semiconductor-superconductor interfaces, while a quest for higher-order non-Abelian excitations demands formation of superconducting contacts to materials with fractionalized excitations, such as a two-dimensional electron gas in a fractional quantum Hall regime. Here we report induced superconductivity in high-mobility two-dimensional electron gas in gallium arsenide heterostructures and development of highly transparent semiconductor-superconductor ohmic contacts. Supercurrent with characteristic temperature dependence of a ballistic junction has been observed across 0.6 μm, a regime previously achieved only in point contacts but essential to the formation of well separated non-Abelian states. High critical fields (>16 T) in NbN contacts enables investigation of an interplay between superconductivity and strongly correlated states in a two-dimensional electron gas at high magnetic fields.

  7. Induced superconductivity in high-mobility two-dimensional electron gas in gallium arsenide heterostructures

    PubMed Central

    Wan, Zhong; Kazakov, Aleksandr; Manfra, Michael J.; Pfeiffer, Loren N.; West, Ken W.; Rokhinson, Leonid P.

    2015-01-01

    Search for Majorana fermions renewed interest in semiconductor–superconductor interfaces, while a quest for higher-order non-Abelian excitations demands formation of superconducting contacts to materials with fractionalized excitations, such as a two-dimensional electron gas in a fractional quantum Hall regime. Here we report induced superconductivity in high-mobility two-dimensional electron gas in gallium arsenide heterostructures and development of highly transparent semiconductor–superconductor ohmic contacts. Supercurrent with characteristic temperature dependence of a ballistic junction has been observed across 0.6 μm, a regime previously achieved only in point contacts but essential to the formation of well separated non-Abelian states. High critical fields (>16 T) in NbN contacts enables investigation of an interplay between superconductivity and strongly correlated states in a two-dimensional electron gas at high magnetic fields. PMID:26067452

  8. Induced superconductivity in high mobility two dimensional electron gas in GaAs heterostructures

    NASA Astrophysics Data System (ADS)

    Rokhinson, Leonid P.

    Search for Majorana fermions renewed interest in semiconductor-superconductor interfaces, while a quest for higher order non-Abelian excitations demands formation of superconducting contacts to materials with fractionalized excitations, e.g. a two-dimensional electron gas in a fractional quantum Hall regime. Here we report induced superconductivity in high mobility two-dimensional electron gas in GaAs heterostructures and development of highly transparent semiconductor-superconductor ohmic contacts. Supercurrent with characteristic temperature dependence of a ballistic junction has been observed across 0.6 μm, a regime previously achieved only in point contacts but essential to the formation of well separated non-Abelian states. High critical fields (> 16 Tesla) in NbN contacts enables investigation of an interplay between superconductivity and strongly correlated states in a two dimensional electron gas at high magnetic fields.

  9. Dedicated mobile high resolution prostate PET imager with an insertable transrectal probe

    DOEpatents

    Majewski, Stanislaw; Proffitt, James

    2010-12-28

    A dedicated mobile PET imaging system to image the prostate and surrounding organs. The imaging system includes an outside high resolution PET imager placed close to the patient's torso and an insertable and compact transrectal probe that is placed in close proximity to the prostate and operates in conjunction with the outside imager. The two detector systems are spatially co-registered to each other. The outside imager is mounted on an open rotating gantry to provide torso-wide 3D images of the prostate and surrounding tissue and organs. The insertable probe provides closer imaging, high sensitivity, and very high resolution predominately 2D view of the prostate and immediate surroundings. The probe is operated in conjunction with the outside imager and a fast data acquisition system to provide very high resolution reconstruction of the prostate and surrounding tissue and organs.

  10. High Mobility SiGe/Si n-MODFET Structures and Devices on Sapphire Substrates

    NASA Technical Reports Server (NTRS)

    Mueller, Carl; Alterovitz, Samuel; Croke, Edward; Ponchak, George

    2004-01-01

    Si/Ge/Si n-type modulation doped field effect structures and transistors (n-MODFET's) have been fabricated on r-plane sapphire substrates. Mobilities as high as 1380 cm(exp 2)/Vs were measured at room temperature. Excellent carrier confinement was shown by Shubnikov-de Haas measurements. Atomic force microscopy indicated smooth surfaces, with rm's roughness less than 4 nm, similar to the quality of SiGe/Si n-MODFET structures made on Si substrates. Transistors with 2 micron gate lengths and 200 micron gate widths were fabricated and tested.

  11. High hole mobility GeSn on insulator formed by self-organized seeding lateral growth

    NASA Astrophysics Data System (ADS)

    Liu, Zhi; Wen, Juanjuan; Zhang, Xu; Li, Chuanbo; Xue, Chunlai; Zuo, Yuhua; Cheng, Buwen; Wang, Qiming

    2014-11-01

    Tensile strained single-crystal GeSn on insulator (GSOI) was obtained using self-organized seeding lateral growth. Segregation of Sn atoms and Sn distribution occurred during the lateral growth of the GeSn stripe. At both edges of the GSOI, Sn concentration distribution was found in good agreement with calculation based on the Scheil equation. P-channel metal-oxide-semiconductor field effect transistors were fabricated using the GSOI materials. Good transistor performance with the low field peak hole mobility of 383 cm2 V-1 s-1 was obtained, which indicated the high quality of this GSOI structure.

  12. Cryogenic, low-noise high electron mobility transistor amplifiers for the Deep Space Network

    NASA Astrophysics Data System (ADS)

    Bautista, J. J.

    1993-11-01

    The rapid advances recently achieved by cryogenically cooled high electron mobility transistor (HEMT) low-noise amplifiers (LNA's) in the 1- to 10-GHz range are making them extremely competitive with maser amplifiers. In order to address future spacecraft navigation, telemetry, radar, and radio science needs, the Deep Space Network is investing both maser and HEMT amplifiers for its Ka-band (32-GHz) downlink capability. This article describes the current state cryogenic HEMT LNA development at Ka-band for the DSN. Noise performance results at S-band (2.3 GHz) and X-band (8.5 GHz) for HEMT's and masers are included for completeness.

  13. Cryogenic, low-noise high electron mobility transistor amplifiers for the Deep Space Network

    NASA Technical Reports Server (NTRS)

    Bautista, J. J.

    1993-01-01

    The rapid advances recently achieved by cryogenically cooled high electron mobility transistor (HEMT) low-noise amplifiers (LNA's) in the 1- to 10-GHz range are making them extremely competitive with maser amplifiers. In order to address future spacecraft navigation, telemetry, radar, and radio science needs, the Deep Space Network is investing both maser and HEMT amplifiers for its Ka-band (32-GHz) downlink capability. This article describes the current state cryogenic HEMT LNA development at Ka-band for the DSN. Noise performance results at S-band (2.3 GHz) and X-band (8.5 GHz) for HEMT's and masers are included for completeness.

  14. Hybrid highly nonlinear fiber for spectral supercontinuum generation in mobile femtosecond clockwork

    NASA Astrophysics Data System (ADS)

    Korel, I. I.; Nyushkov, B. N.; Denisov, V. I.; Pivtsov, V. S.; Koliada, N. A.; Sysoliatin, A. A.; Ignatovich, S. M.; Kvashnin, N. L.; Skvortsov, M. N.; Bagayev, S. N.

    2014-07-01

    We have proposed and tested a novel design of a short-length dispersion-managed hybrid highly nonlinear fiber (HNLF), which is intended for low-noise spectral supercontinuum generation with controlled intensity distribution over the range 1-2 µm. It is shown experimentally that such a HNLF facilitates development of a mobile femtosecond optical clockwork, which is based on a fiber-optic femtosecond laser system and an original fiber-coupled Nd : YAG/I2 optical frequency standard with a long-term instability lowered to 3 × 10-15.

  15. Negative huge magnetoresistance in high-mobility 2D electron gases: DC-current dependence

    NASA Astrophysics Data System (ADS)

    Iñarrea, J.; Bockhorn, L.; Haug, R. J.

    2016-07-01

    Two-dimensional electron gases with very high mobility show a huge or giant negative magnetoresistance at low temperatures and low magnetic fields. We present an experimental and theoretical work on the influence of the applied current on the negative huge magnetoresistance of these systems. We obtain an unexpected and strong nonlinear behavior consisting in an increase of the negative huge magnetoresistance with increasing current, in other words, for increasing current the magnetoresistance collapses at small magnetic fields. This nonlinearity is explained by the subtle interplay of elastic scattering within Landau levels and between Landau levels.

  16. High-level waste tank modifications, installation of mobilization equipment/check out

    SciTech Connect

    Schiffhauer, M.A.; Thompson, S.C.

    1992-08-31

    PUREX high-level waste (HLW) is contained at the West Valley Demonstration Project (WVDP) in an underground carbon-steel storage tank. The HLW consists of a precipitated sludge and an alkaline supernate. This report describes the system that the WVDP has developed and implemented to resuspend and wash the HLW sludge from the tank. The report discusses Sludge Mobilization and Wash System (SMWS) equipment design, installation, and testing. The storage tank required modifications to accommodate the SMWS. These modifications are discussed as well.

  17. Highly sensitive detection of a bio-threat pathogen by gold nanoparticle-based oligonucleotide-linked immunosorbent assay.

    PubMed

    Seo, Sang-Hwan; Lee, Young-Ran; Ho Jeon, Jun; Hwang, Yi-Rang; Park, Pil-Gu; Ahn, Dae-Ro; Han, Ki-Cheol; Rhie, Gi-Eun; Hong, Kee-Jong

    2015-02-15

    Francisella (F.) tularensis causes the zoonotic disease tularemia and categorized as one of the highest-priority biological agents. The sensing approaches utilized by conventional detection methods, including enzyme-linked immunosorbent assay (ELISA), are not sensitive enough to identify an infectious dose of this high-risk pathogen due to its low infective dose. As an attempt to detect F. tularensis with high sensitivity, we utilized the highly sensitive immunoassay system named gold nanoparticle-based oligonucleotide-linked immunosorbent assay (GNP-OLISA) which uses antibody-gold nanoparticles conjugated with DNA strands as a signal generator and RNA oligonucleotides appended with a fluorophore as a quencher for signal amplification. We modified the GNP-OLISA for the detection F. tularensis to utilize one antibody for both the capture of the target and for signal generation instead of using two different antibodies, which are usually employed to construct the antibody sandwich in the ELISA. The GNP-OLISA showed 37-fold higher sensitivity compared with ELISA and generated very consistent detection results in the sera. In addition, the detection specificity was not affected by the presence of non-target bacteria, suggesting that GNP-OLISA can be used as a sensitive detection platform for monitoring high-risk pathogens thereby overcoming the limit of the conventional assay system. PMID:25194798

  18. Investigations of high mobility single crystal chemical vapor deposition diamond for radiotherapy photon beam monitoring

    SciTech Connect

    Tromson, D.; Descamps, C.; Tranchant, N.; Bergonzo, P.; Nesladek, M.; Isambert, A.

    2008-03-01

    The intrinsic properties of diamond make this material theoretically very suitable for applications in medical physics. Until now ionization chambers have been fabricated from natural stones and are commercialized by PTW, but their fairly high costs and long delivery times have often limited their use in hospital. The properties of commercialized intrinsic polycrystalline diamond were investigated in the past by many groups. The results were not completely satisfactory due to the nature of the polycrystalline material itself. In contrast, the recent progresses in the growth of high mobility single crystal synthetic diamonds prepared by chemical vapor deposition (CVD) technique offer new alternatives. In the framework of the MAESTRO project (Methods and Advanced Treatments and Simulations for Radio Oncology), the CEA-LIST is studying the potentialities of synthetic diamond for new techniques of irradiation such as intensity modulated radiation therapy. In this paper, we present the growth and characteristics of single crystal diamond prepared at CEA-LIST in the framework of the NoRHDia project (Novel Radiation Hard CVD Diamond Detector for Hadrons Physics), as well as the investigations of high mobility single crystal CVD diamond for radiotherapy photon beam monitoring: dosimetric analysis performed with the single crystal diamond detector in terms of stability and repeatability of the response signal, signal to noise ratio, response speed, linearity of the signal versus the absorbed dose, and dose rate. The measurements performed with photon beams using radiotherapy facilities demonstrate that single crystal CVD diamond is a good alternative for air ionization chambers for beam quality control.

  19. Theory of intermediate- and high-field mobility in dilute nitride alloys

    NASA Astrophysics Data System (ADS)

    Seifikar, Masoud; O'Reilly, Eoin P.; Fahy, Stephen

    2011-10-01

    We have solved the steady-state Boltzmann transport equation in bulk GaAs1-xNx. Two different models of the conduction band structure have been studied to investigate the behavior of electrons with increasing electric field in these alloys: (1) carriers in parabolic Γ and L bands are scattered by resonant nitrogen substitutional defect states, polar optic and acoustic phonons, and intervalley optical phonons; (2) carriers, constrained in the lower band of the band-anticrossing (BAC) model, are scattered by phonons and by nitrogen states. We consider scattering both by isolated N atoms and also by a full distribution of N states. We find that it is necessary to include the full distribution of levels in order to account for the small low-field mobility and the absence of a negative differential velocity regime observed experimentally with increasing x. Model 2 breaks down at intermediate and high field, due to the unphysical constraint of limiting carriers to the lower BAC band. For model 1, carrier scattering into the L bands is reduced at intermediate electric fields but is comparable at high fields to that observed in GaAs, with the calculated high-field mobility and carrier distribution then also being comparable to GaAs. Overall the results account well for a wide range of experimental data.

  20. Highly mobile and reactive state of hydrogen in metal oxide semiconductors at room temperature

    NASA Astrophysics Data System (ADS)

    Chen, Wan Ping; He, Ke Feng; Wang, Yu; Chan, Helen Lai Wah; Yan, Zijie

    2013-11-01

    Hydrogen in metal oxides usually strongly associates with a neighboring oxygen ion through an O-H bond and thus displays a high stability. Here we report a novel state of hydrogen with unusually high mobility and reactivity in metal oxides at room temperature. We show that freshly doped hydrogen in Nb2O5 and WO3 polycrystals via electrochemical hydrogenation can reduce Cu2+ ions into Cu0 if the polycrystals are immersed in a CuSO4 solution, while this would not happen if the hydrogenated polycrystals have been placed in air for several hours before the immersion. Time-dependent studies of electrochemically hydrogenated rutile single crystals reveal two distinct states of hydrogen: one as protons covalently bonded to oxygen ions, while the other one is highly unstable with a lifetime of just a few hours. Observation of this mobile and reactive state of hydrogen will provide new insight into numerous moderate and low temperature interactions between metal oxides and hydrogen.

  1. Ballistic superconductivity in high mobility two dimensional electron gas in GaAs heterostructures

    NASA Astrophysics Data System (ADS)

    Wan, Zhong; Kazakov, Aleksandr; Manfra, Michael; Pfeiffer, Loren; West, Ken; Rokhinson, Leonid

    2015-03-01

    Introduction of a Josephson field effect transistor (JoFET) concept sparked active research on proximity effects in semiconductors. Induced superconductivity and electrostatic control of critical current has been demonstrated in two-dimensional gases in InAs, graphene and topological insulators, and in one-dimensional systems including quantum spin Hall edges. Recently, interest in superconductor-semiconductor interfaces was renewed by the search for non-Abelian states when fractional quantum Hall edge states interface with superconductivity. However, the highest mobility 2D gases in GaAs, where variety of strongly correlated states including fractional quantum Hall effect can be observed, are notoriously absent from the list of materials where superconductivity have been induced. We report formation of transparent superconducting contacts to the high mobility 2DEG in GaAs and demonstrate induced superconductivity across several microns. Ballistic supercurrent has been observed across 0.6 μm of 2DEG, a regime essential to the formation of well separated non-Abelian states. High critical fields (> 16 Tesla) in NbN contacts enables investigation of a regime of an interplay between superconductivity and strongly correlated states in a 2DEG at high magnetic fields.

  2. Lactobacillus crispatus L1: high cell density cultivation and exopolysaccharide structure characterization to highlight potentially beneficial effects against vaginal pathogens

    PubMed Central

    2014-01-01

    Background Vaginal lactic acid bacteria defend the host against pathogens through a combination of competitive exclusion, competition for nutrients, production of antimicrobial substances and through the activation of the immune system. A new human isolate named Lactobacillus crispatus L1 was characterized in this work, and a preliminary evaluation of its probiotic potential is described together with a process to obtain a high productivity of viable biomass. Results In a simulated digestion process 1.8⋅1010 cells∙ml−1 survived the gastric environment with 80% viability, without being affected by small intestine juices. Experiments on six different C sources were performed to analyze growth and organic acids production and, glucose, provided the best performances. A microfiltration strategy was exploited to improve the cellular yield in 2 L-fermentation processes, reaching 27 g · l−1 of dry biomass. Moreover, L. crispatus L1 demonstrated a greater stability to high concentrations of lactic acid, compared to other lactobacilli. The specific L. crispatus L1 exopolysaccharide was purified from the fermentation broth and characterized by NMR showing structural features and similarity to exopolysaccharides produced by pathogenic strains. Live L. crispatus L1 cells strongly reduced adhesion of a yeast pathogenic strain, Candida albicans in particular, in adherence assays. Interestingly a higher expression of the human defensin HBD-2 was also observed in vaginal cells treated with the purified exopolysaccharide, indicating a possible correlation with C. albicans growth inhibition. Conclusions The paper describes the evaluation of L. crispatus L1 as potential vaginal probiotic and the fermentation processes to obtain high concentrations of viable cells. PMID:24884965

  3. Bloodborne pathogens

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000453.htm Bloodborne pathogens To use the sharing features on this page, please enable JavaScript. A pathogen is something that causes disease. Germs that can ...

  4. Electron transport in bulk-Si NMOSFETs in presence of high-kappa gate insulator: Charge trapping and mobility

    NASA Astrophysics Data System (ADS)

    Maitra, Kingsuk

    Recent advancements in gate stack engineering has led to the development of aggressively scaled, high mobility, high-kappa dielectric based NMOSFETs with metal gates. Most of the current literature on the subject also stressed on the need for a high temperature process step to attain the high mobility under minimal change of effective oxide thickness. However, the physical origin of high mobility is not well understood. In this work, fundamental insight into the necessity of the high temperature process step is provided. Novel experimental strategies are developed to understand the impact of interface states and bulk traps separately and exclusively on channel mobility. It is conjectured that the interface states at the SiO2/(100) bulk-Si interface are identical in nature (as far as coupling with the channel electrons is concerned) to those at the high-kappa/SiO2/(100) bulk-Si interface. Thus, the response of interface states on channel electrons in high-kappa insulator based NMOSFETs is properly calibrated by a novel thermal desorption of hydrogen experiment on SiO2/(100) bulk-Si NMOSFETs to yield a highly accurate parameterized equation. The value of interface state response parameter determined by the aforementioned experiment is compared with theoretical predictions, and independently determined projections from electrical stress measurements. The impact of transient charging on transport in the channel is investigated. It is conclusively shown that remote charge has minimal impact on mobility in the channel. The role of nitrogen induced fixed oxide charge is studied on a set of Hf-silicate samples. Role of soft optical phonon scattering and the beneficial impact of metal gates on soft optical phonon limited mobility are thoroughly investigated both theoretically and experimentally. Conclusions are drawn on the fundamental limit of mobility attainable in high-kappa dielectric based NMOSFETs.

  5. GaN High-Electron-Mobility Transistor with WN x /Cu Gate for High-Power Applications

    NASA Astrophysics Data System (ADS)

    Hsieh, Ting-En; Lin, Yueh-Chin; Li, Fang-Ming; Shi, Wang-Cheng; Huang, Yu-Xiang; Lan, Wei-Cheng; Chin, Ping-Chieh; Chang, Edward Yi

    2015-12-01

    A GaN high-electron-mobility transistor (HEMT) with WN x /Cu gate for high-power applications has been investigated. The direct-current (DC) characteristics of the device are comparable to those of conventional Ni/Au-gated GaN HEMTs. The results of high-voltage stress testing indicate that the device is stable after application of 200 V stress for 42 h. The WN x /Cu-gated GaN HEMT exhibited no obvious changes in the DC characteristics or Schottky barrier height before and after annealing at 250°C for 1 h. These results demonstrate that the WN x /Cu gate structure can be used in a GaN HEMT for high-power applications with good thermal stability.

  6. Travelling-wave ion mobility and negative ion fragmentation of high-mannose N-glycans.

    PubMed

    Harvey, David J; Scarff, Charlotte A; Edgeworth, Matthew; Struwe, Weston B; Pagel, Kevin; Thalassinos, Konstantinos; Crispin, Max; Scrivens, Jim

    2016-03-01

    The isomeric structure of high-mannose N-glycans can significantly impact biological recognition events. Here, the utility of travelling-wave ion mobility mass spectrometry for isomer separation of high-mannose N-glycans is investigated. Negative ion fragmentation using collision-induced dissociation gave more informative spectra than positive ion spectra with mass-different fragment ions characterizing many of the isomers. Isomer separation by ion mobility in both ionization modes was generally limited, with the arrival time distributions (ATD) often showing little sign of isomers. However, isomers could be partially resolved by plotting extracted fragment ATDs of the diagnostic fragment ions from the negative ion spectra, and the fragmentation spectra of the isomers could be extracted by using ions from limited areas of the ATD peak. In some cases, asymmetric ATDs were observed, but no isomers could be detected by fragmentation. In these cases, it was assumed that conformers or anomers were being separated. Collision cross sections of the isomers in positive and negative fragmentation mode were estimated from travelling-wave ion mobility mass spectrometry data using dextran glycans as calibrant. More complete collision cross section data were achieved in negative ion mode by utilizing the diagnostic fragment ions. Examples of isomer separations are shown for N-glycans released from the well-characterized glycoproteins chicken ovalbumin, porcine thyroglobulin and gp120 from the human immunodeficiency virus. In addition to the cross-sectional data, details of the negative ion collision-induced dissociation spectra of all resolved isomers are discussed. PMID:26956389

  7. GaN high electron mobility transistors for sub-millimeter wave applications

    NASA Astrophysics Data System (ADS)

    Seup Lee, Dong; Liu, Zhihong; Palacios, Tomás

    2014-10-01

    This paper reviews different technologies recently developed to push the performance of GaN-based high electron mobility transistors (HEMTs) into sub-mm wave frequencies. To understand the impact and need of each technology, a device delay model based on small-signal equivalent circuit parameters is introduced, which divides the total device delay into intrinsic, extrinsic, and parasitic components. Then, several technologies to improve the speed of GaN HEMTs are discussed according to their contribution on each delay component. Finally, the key limiting factors for the high speed operation of these transistors under high drain or gate bias range are studied and novel approaches to solve these problems are presented.

  8. Highly Pathogenic Avian Influenza A(H5N1) Virus Struck Migratory Birds in China in 2015

    PubMed Central

    Bi, Yuhai; Zhang, Zhenjie; Liu, Wenjun; Yin, Yanbo; Hong, Jianmin; Li, Xiangdong; Wang, Haiming; Wong, Gary; Chen, Jianjun; Li, Yunfeng; Ru, Wendong; Gao, Ruyi; Liu, Di; Liu, Yingxia; Zhou, Boping; Gao, George F.; Shi, Weifeng; Lei, Fumin

    2015-01-01

    Approximately 100 migratory birds, including whooper swans and pochards, were found dead in the Sanmenxia Reservoir Area of China during January 2015. The causative agent behind this outbreak was identified as H5N1 highly pathogenic avian influenza virus (HPAIV). Genetic and phylogenetic analyses revealed that this Sanmenxia H5N1 virus was a novel reassortant, possessing a Clade 2.3.2.1c HA gene and a H9N2-derived PB2 gene. Sanmenxia Clade 2.3.2.1c-like H5N1 viruses possess the closest genetic identity to A/Alberta/01/2014 (H5N1), which recently caused a fatal respiratory infection in Canada with signs of meningoencephalitis, a highly unusual symptom with influenza infections in humans. Furthermore, this virus was shown to be highly pathogenic to both birds and mammals, and demonstrate tropism for the nervous system. Due to the geographical location of Sanmenxia, these novel H5N1 viruses also have the potential to be imported to other regions through the migration of wild birds, similar to the H5N1 outbreak amongst migratory birds in Qinghai Lake during 2005. Therefore, further investigation and monitoring is required to prevent this novel reassortant virus from becoming a new threat to public health. PMID:26259704

  9. Differences in pathogenicity, response to vaccination, and innate immune responses in different types of ducks infected with a virulent H5N1 highly pathogenic avian influenza virus from Vietnam

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Wild ducks are reservoirs of avian influenza viruses in nature, and usually don’t show signs of disease. However, some Asian lineage H5N1 highly pathogenic avian influenza (HPAI) viruses can cause disease and death in both wild and domestic ducks. The objective of this study was to compare the cli...

  10. Combinatorial Screening of the Effect of Temperature on the Microstructure and Mobility of a High Performance Polythiophene Semiconductor

    SciTech Connect

    Lucas,L.; Delongchamp, D.; Vogel, B.; Lin, E.; Fasolka, M.; Fischer, D.; Mcculloch, I.; Heeney, M.; Jabbour, G.

    2007-01-01

    Using a gradient combinatorial approach, the authors report the effects of temperature on the microstructure and hole mobility of poly(2,5-bis(3-dodecylthiophen-2yl)thieno[3,2-b]thiophene) thin films for application in organic field-effect transistors. The gradient heating revealed a detailed dependence on thermal history. Optimal heat treatment achieved mobilities as high as 0.3 cm{sup 2} V{sup -1} s{sup -1}. Mobility enhancement coincides with an increase in crystal domain size and orientation, all of which occur abruptly at a temperature closely corresponding to a bulk liquid crystal phase transition.

  11. Combinatorial screening of the effect of temperature on the microstructure and mobility of a high performance polythiophene semiconductor

    NASA Astrophysics Data System (ADS)

    Lucas, Leah A.; DeLongchamp, Dean M.; Vogel, Brandon M.; Lin, Eric K.; Fasolka, Michael J.; Fischer, Daniel A.; McCulloch, Iain; Heeney, Martin; Jabbour, Ghassan E.

    2007-01-01

    Using a gradient combinatorial approach, the authors report the effects of temperature on the microstructure and hole mobility of poly(2,5-bis(3-dodecylthiophen-2yl)thieno[3,2-b]thiophene) thin films for application in organic field-effect transistors. The gradient heating revealed a detailed dependence on thermal history. Optimal heat treatment achieved mobilities as high as 0.3cm2V-1s-1. Mobility enhancement coincides with an increase in crystal domain size and orientation, all of which occur abruptly at a temperature closely corresponding to a bulk liquid crystal phase transition.

  12. Phosphorene: an unexplored 2D semiconductor with a high hole mobility.

    PubMed

    Liu, Han; Neal, Adam T; Zhu, Zhen; Luo, Zhe; Xu, Xianfan; Tománek, David; Ye, Peide D

    2014-04-22

    We introduce the 2D counterpart of layered black phosphorus, which we call phosphorene, as an unexplored p-type semiconducting material. Same as graphene and MoS2, single-layer phosphorene is flexible and can be mechanically exfoliated. We find phosphorene to be stable and, unlike graphene, to have an inherent, direct, and appreciable band gap. Our ab initio calculations indicate that the band gap is direct, depends on the number of layers and the in-layer strain, and is significantly larger than the bulk value of 0.31-0.36 eV. The observed photoluminescence peak of single-layer phosphorene in the visible optical range confirms that the band gap is larger than that of the bulk system. Our transport studies indicate a hole mobility that reflects the structural anisotropy of phosphorene and complements n-type MoS2. At room temperature, our few-layer phosphorene field-effect transistors with 1.0 μm channel length display a high on-current of 194 mA/mm, a high hole field-effect mobility of 286 cm(2)/V·s, and an on/off ratio of up to 10(4). We demonstrate the possibility of phosphorene integration by constructing a 2D CMOS inverter consisting of phosphorene PMOS and MoS2 NMOS transistors. PMID:24655084

  13. Electrical detection of biomaterials using AlGaN/GaN high electron mobility transistors

    NASA Astrophysics Data System (ADS)

    Kang, B. S.; Wang, H. T.; Ren, F.; Pearton, S. J.

    2008-08-01

    Chemical sensors can be used to analyze a wide variety of environmental and biological gases and liquids and may need to be able to selectively detect a target analyte. Different methods, including gas chromatography, chemiluminescence, selected ion flow tube, and mass spectroscopy, have been used to measure biomarkers. These methods show variable results in terms of sensitivity for some applications and may not meet the requirements for a handheld biosensor. A promising sensing technology utilizes AlGaN/GaN high electron mobility transistors (HEMTs). HEMT structures have been developed for use in microwave power amplifiers due to their high two dimensional electron gas (2DEG) mobility and saturation velocity. The conducting 2DEG channel of AlGaN/GaN HEMTs is very close to the surface and extremely sensitive to adsorption of analytes. HEMT sensors can be used for detecting gases, ions, pH values, proteins, and DNA. In this paper we review recent progress on functionalizing the surface of HEMTs for specific detection of glucose, kidney marker injury molecules, prostate cancer, and other common substances of interest in the biomedical field.

  14. P-doping-free III-nitride high electron mobility light-emitting diodes and transistors

    SciTech Connect

    Li, Baikui; Tang, Xi; Chen, Kevin J.; Wang, Jiannong

    2014-07-21

    We report that a simple metal-AlGaN/GaN Schottky diode is capable of producing GaN band-edge ultraviolet emission at 3.4 eV at a small forward bias larger than ∼2 V at room temperature. Based on the surface states distribution of AlGaN, a mature impact-ionization-induced Fermi-level de-pinning model is proposed to explain the underlying mechanism of the electroluminescence (EL) process. By experimenting with different Schottky metals, Ni/Au and Pt/Au, we demonstrated that this EL phenomenon is a “universal” property of metal-AlGaN/GaN Schottky diodes. Since this light-emitting Schottky diode shares the same active structure and fabrication processes as the AlGaN/GaN high electron mobility transistors, straight-forward and seamless integration of photonic and electronic functional devices has been demonstrated on doping-free III-nitride heterostructures. Using a semitransparent Schottky drain electrode, an AlGaN/GaN high electron mobility light-emitting transistor is demonstrated.

  15. Subtidal circulation patterns in a shallow, highly stratified estuary: Mobile Bay, Alabama

    USGS Publications Warehouse

    Noble, M.A.; Schroeder, W.W.; Wiseman, W.J., Jr.; Ryan, H.F.; Gelfenbaum, G.

    1996-01-01

    Mobile Bay is a wide (25-50 km), shallow (3 m), highly stratified estuary on the Gulf coast of the United States. In May 1991 a series of instruments that measure near-surface and near-bed current, temperature, salinity, and middepth pressure were deployed for a year-long study of the bay. A full set of measurements were obtained at one site in the lower bay; all but current measurements were obtained at a midbay site. These observations show that the subtidal currents in the lower bay are highly sheared, despite the shallow depth of the estuary. The sheared flow patterns are partly caused by differential forcing from wind stress and river discharge. Two wind-driven flow patterns actually exist in lower Mobile Bay. A barotropic response develops when the difference between near-surface and near-bottom salinity is less than 5 parts per thousand. For stronger salinity gradients the wind-driven currents are larger and the response resembles a baroclinic flow pattern. Currents driven by river flows are sheared and also have a nonlinear response pattern. Only near-surface currents are driven seaward by discharges below 3000 m3/s. At higher discharge rates, surface current variability uncouples from the river flow and the increased discharge rates drive near-bed current seaward. This change in the river-forced flow pattern may be associated with a hydraulic jump in the mouth of the estuary. Copyright 1996 by the American Geophysical Union.

  16. Automatic and robust extrinsic camera calibration for high-accuracy mobile mapping

    NASA Astrophysics Data System (ADS)

    Goeman, Werner; Douterloigne, Koen; Bogaert, Peter; Pires, Rui; Gautama, Sidharta

    2012-10-01

    A mobile mapping system (MMS) is the answer of the geoinformation community to the exponentially growing demand for various geospatial data with increasingly higher accuracies and captured by multiple sensors. As the mobile mapping technology is pushed to explore its use for various applications on water, rail, or road, the need emerges to have an external sensor calibration procedure which is portable, fast and easy to perform. This way, sensors can be mounted and demounted depending on the application requirements without the need for time consuming calibration procedures. A new methodology is presented to provide a high quality external calibration of cameras which is automatic, robust and fool proof.The MMS uses an Applanix POSLV420, which is a tightly coupled GPS/INS positioning system. The cameras used are Point Grey color video cameras synchronized with the GPS/INS system. The method uses a portable, standard ranging pole which needs to be positioned on a known ground control point. For calibration a well studied absolute orientation problem needs to be solved. Here, a mutual information based image registration technique is studied for automatic alignment of the ranging pole. Finally, a few benchmarking tests are done under various lighting conditions which proves the methodology's robustness, by showing high absolute stereo measurement accuracies of a few centimeters.

  17. High-mobility three-atom-thick semiconducting films with wafer-scale homogeneity.

    PubMed

    Kang, Kibum; Xie, Saien; Huang, Lujie; Han, Yimo; Huang, Pinshane Y; Mak, Kin Fai; Kim, Cheol-Joo; Muller, David; Park, Jiwoong

    2015-04-30

    The large-scale growth of semiconducting thin films forms the basis of modern electronics and optoelectronics. A decrease in film thickness to the ultimate limit of the atomic, sub-nanometre length scale, a difficult limit for traditional semiconductors (such as Si and GaAs), would bring wide benefits for applications in ultrathin and flexible electronics, photovoltaics and display technology. For this, transition-metal dichalcogenides (TMDs), which can form stable three-atom-thick monolayers, provide ideal semiconducting materials with high electrical carrier mobility, and their large-scale growth on insulating substrates would enable the batch fabrication of atomically thin high-performance transistors and photodetectors on a technologically relevant scale without film transfer. In addition, their unique electronic band structures provide novel ways of enhancing the functionalities of such devices, including the large excitonic effect, bandgap modulation, indirect-to-direct bandgap transition, piezoelectricity and valleytronics. However, the large-scale growth of monolayer TMD films with spatial homogeneity and high electrical performance remains an unsolved challenge. Here we report the preparation of high-mobility 4-inch wafer-scale films of monolayer molybdenum disulphide (MoS2) and tungsten disulphide, grown directly on insulating SiO2 substrates, with excellent spatial homogeneity over the entire films. They are grown with a newly developed, metal-organic chemical vapour deposition technique, and show high electrical performance, including an electron mobility of 30 cm(2) V(-1) s(-1) at room temperature and 114 cm(2) V(-1) s(-1) at 90 K for MoS2, with little dependence on position or channel length. With the use of these films we successfully demonstrate the wafer-scale batch fabrication of high-performance monolayer MoS2 field-effect transistors with a 99% device yield and the multi-level fabrication of vertically stacked transistor devices for three

  18. Assessment of the Internal Genes of Influenza A (H7N9) Virus Contributing to High Pathogenicity in Mice

    PubMed Central

    Bi, Yuhai; Xie, Qing; Zhang, Shuang; Li, Yun; Xiao, Haixia; Jin, Tao; Zheng, Weinan; Li, Jing; Jia, Xiaojuan; Sun, Lei; Liu, Jinhua; Qin, Chuan

    2014-01-01

    ABSTRACT The recently identified H7N9 influenza A virus has caused severe economic losses and worldwide public concern. Genetic analysis indicates that its six internal genes all originated from H9N2 viruses. However, the H7N9 virus is more highly pathogenic in humans than H9N2, which suggests that the internal genes of H7N9 have mutated. To analyze which H7N9 virus internal genes contribute to its high pathogenicity, a series of reassortants was generated by reverse genetics, with each virus containing a single internal gene of the typical A/Anhui/1/2013 (H7N9) (AH-H7N9) virus in the genetic background of the A/chicken/Shandong/lx1023/2007 (H9N2) virus. The replication ability, polymerase activity, and pathogenicity of these viruses were then evaluated in vitro and in vivo. These recombinants displayed high genetic compatibility, and the H7N9-derived PB2, M, and NP genes were identified as the virulence genes for the reassortants in mice. Further investigation confirmed that the PB2 K627 residue is critical for the high pathogenicity of the H7N9 virus and the reassortant containing the H7N9-derived PB2 segment (H9N2-AH/PB2). Notably, the H7N9-derived PB2 gene displayed greater compatibility with the H9N2 genome than that of H7N9, endowing the H9N2-AH/PB2 reassortant with greater viability and virulence than the parental H7N9 virus. In addition, the H7N9 virus, with the exception of the H9N2 reassortants, could effectively replicate in human A549 cells. Our results indicate that PB2, M, and NP are the key virulence genes, together with the surface hemagglutinin (HA) and neuraminidase (NA) proteins, contributing to the high infectivity of the H7N9 virus in humans. IMPORTANCE To date, the novel H7N9 influenza A virus has caused 437 human infections, with approximately 30% mortality. Previous work has primarily focused on the two viral surface proteins, HA and NA, but the contribution of the six internal genes to the high pathogenicity of H7N9 has not been

  19. High carrier mobility in ultrapure diamond measured by time-resolved cyclotron resonance

    SciTech Connect

    Akimoto, Ikuko Handa, Yushi; Fukai, Katsuyuki; Naka, Nobuko

    2014-07-21

    We have performed time-resolved cyclotron resonance measurements in ultrapure diamond crystals for the temperature range of T=7.3–40 K and obtained the temperature-dependent momentum relaxation times based on the cyclotron resonance widths for optically generated electrons and holes. The relaxation time follows a T{sup −3/2} law down to 12 K, which is expected for acoustic-phonon scattering without impurity effect because of the high purity of our samples. The deviation from the law at lower temperatures is explained by the impurity scattering and the breakdown of the high-temperature approximation for the phonon scattering. We extract the carrier drift mobility by using the directly measured effective masses and the relaxation times. The mobility at 10 K for 600 ns delay time after optical injection is found to be μ{sub e}=1.5×10{sup 6} cm{sup 2}/V s for the electrons, and μ{sub lh}=2.3×10{sup 6} cm{sup 2}/V s and  μ{sub hh}=2.4×10{sup 5} cm{sup 2}/V s for the light and heavy holes, respectively. These high values are achieved by our high-sensitivity detection for low-density carriers (at <10{sup 11} cm{sup −3}) free from the carrier-carrier scattering as well as by the suppression of the impurity scattering in the high-purity samples.

  20. Mobile Phone Use in a Pennsylvania Public High School: Does Policy Inform Practice?

    ERIC Educational Resources Information Center

    Thackara, Susan Tomchak

    2014-01-01

    Though many American educators embrace technology in classrooms, administrators can create policies that inhibit technology such as mobile phone use in classrooms or on district property. These policies range from restrictive with no mobile phone use permitted, to liberal in which unrestricted use of mobile phones is allowed. The purpose of this…