5,420 research outputs found
Microbial diversity in the thermal springs within Hot Springs National Park
The thermal water systems of Hot Springs National Park (HSNP) in Hot Springs, Arkansas exist in relative isolation from other North American thermal systems. The HSNP waters could therefore serve as a unique center of thermophilic microbial biodiversity. However, these springs remain largely unexplored using culture-independent next generation sequencing techniques to classify species of thermophilic organisms. Additionally, HSNP has been the focus of anthropogenic development, capping and diverting the springs for use in recreational bathhouse facilities. Human modification of these springs may have impacted the structure of these bacterial communities compared to springs left in a relative natural state. The goal of this study was to compare the community structure in two capped springs and two uncapped springs in HSNP, as well as broadly survey the microbial diversity of the springs. We used Illumina 16S rRNA sequencing of water samples from each spring, the QIIME workflow for sequence analysis, and generated measures of genera and phyla richness, diversity, and evenness. In total, over 700 genera were detected and most individual samples had more than 100 genera. There were also several uncharacterized sequences that could not be placed in known taxa, indicating the sampled springs contain undescribed bacteria. There was great variation both between sites and within samples, so no significant differences were detected in community structure between sites. Our results suggest that these springs, regardless of their human modification, contain a considerable amount of biodiversity, some of it potentially unique to the study site
The WTO Panel Decision on Australia\u27s Salmon Import Guidelines: Evidence That the SPS Agreement Can Effectively Protect Human Health Interests
On July 19, 1999, Australia lifted its ban on salmon imports and announced new salmon import guidelines. The new guidelines were promulgated in response to a World Trade Organization ( WTO ) Appellate Body determination that the import ban violated the Agreement on the Application of Sanitary and Phytosanitary Measures ( SPS Agreement ). Canada challenged Australia\u27s new import guidelines, alleging that the new guidelines also violate the SPS Agreement. The WTO dispute settlement panel held that, with the exception of only one provision, Australia\u27s new salmon import guidelines are based on appropriate scientific risk analyses and are now in line with comparable import guidelines for non-salmonid fish. By rejecting most of Canada\u27s challenges and substantially upholding Australia\u27s new import guidelines, the dispute settlement panel demonstrated that the SPS Agreement can be used by WTO member countries to protect their human health interests
European Flight Restrictions May Inhibit International Propagation of Ebola
The rise of aviation as the dominant form of international transportation has increased the potential for the spread of infectious diseases. The 2014 West African Ebola Outbreak is no exception, with localized outbreaks in multiple countries caused by infected individuals traveling by plane. To inhibit the spread of Ebola to the United States it has been suggested that airlines cancel direct inbound flights from the affected region. To examine the effects of this approach, we developed and analyzed an agent-based metapopulation network model to simulate the international flight-based spread of Ebola. A metapopulation network consisting of 3,052 subpopulations connected by 83,295 flights was developed to simulate the transportation and infection of individuals in discrete timesteps of 30 minutes. To simulate the transmission dynamics of Ebola within subpopulations, airports, and flights, we constructed an SEIR model in which individuals are classified as either susceptible, exposed, infectious, or removed. The spread of Ebola was simulated using an R0 of 2.1, as estimated for the 2014 West African Ebola outbreak, and extrapolated to scenarios of unilateral flight restrictions. We tested situations in which the United States, the European Union, or other African nations refused inbound flights. We found that flight restrictions can decrease the number of subpopulations with infectious or exposed individuals, with European-bound flight restrictions decreasing the spread of Ebola by as much as 80%. While flight restrictions may be politically and economically infeasible, our model suggests that the implementation of flight restrictions on European-bound flights may effectively mitigate the international spread of Ebola
Suppression of allergic airway inflammation by helminth-induced regulatory T cells
Allergic diseases mediated by T helper type (Th) 2 cell immune responses are rising dramatically in most developed countries. Exaggerated Th2 cell reactivity could result, for example, from diminished exposure to Th1 cell–inducing microbial infections. Epidemiological studies, however, indicate that Th2 cell–stimulating helminth parasites may also counteract allergies, possibly by generating regulatory T cells which suppress both Th1 and Th2 arms of immunity. We therefore tested the ability of the Th2 cell–inducing gastrointestinal nematode Heligmosomoides polygyrus to influence experimentally induced airway allergy to ovalbumin and the house dust mite allergen Der p 1. Inflammatory cell infiltrates in the lung were suppressed in infected mice compared with uninfected controls. Suppression was reversed in mice treated with antibodies to CD25. Most notably, suppression was transferable with mesenteric lymph node cells (MLNC) from infected animals to uninfected sensitized mice, demonstrating that the effector phase was targeted. MLNC from infected animals contained elevated numbers of CD4(+)CD25(+)Foxp3(+) T cells, higher TGF-β expression, and produced strong interleukin (IL)-10 responses to parasite antigen. However, MLNC from IL-10–deficient animals transferred suppression to sensitized hosts, indicating that IL-10 is not the primary modulator of the allergic response. Suppression was associated with CD4(+) T cells from MLNC, with the CD4(+)CD25(+) marker defining the most active population. These data support the contention that helminth infections elicit a regulatory T cell population able to down-regulate allergen induced lung pathology in vivo
Nonaqueous slip casting of YBa2Cu3O(7-x) superconductive ceramics
This study investigates the slip casting of YBa2Cu3O(7-x) powders using nonaqueous carrier liquids and fired ceramic molds. The parameters of the process examined here include the rheological properties of YBa2Cu3O(7-x) powder dispersed in various solvent/dispersant systems, the combination of nonaqueous slips with fired ceramic molds to form the superconductive ceramics, the process-property relationships using a four-factor factorial experiment, and the applicability of magnetic fields to align the YBa2Cu3O(7-x) grains during the casting process
Assessment of DNA extracted from FTA® cards for use on the Illumina iSelect BeadChip
<p>Abstract</p> <p>Background</p> <p>As FTA<sup>® </sup>cards provide an ideal medium for the field collection of DNA we sought to assess the quality of genomic DNA extracted from this source for use on the Illumina BovineSNP50 iSelect BeadChip which requires unbound, relatively intact (fragment sizes ≥ 2 kb), and high-quality DNA. Bovine blood and nasal swab samples collected on FTA cards were extracted using the commercially available GenSolve kit with a minor modification. The call rate and concordance of genotypes from each sample were compared to those obtained from whole blood samples extracted by standard PCI extraction.</p> <p>Findings</p> <p>An ANOVA analysis indicated no significant difference (P > 0.72) in BovineSNP50 genotype call rate between DNA extracted from FTA cards by the GenSolve kit or extracted from whole blood by PCI. Two sample t-tests demonstrated that the DNA extracted from the FTA cards produced genotype call and concordance rates that were not different to those produced by assaying DNA samples extracted by PCI from whole blood.</p> <p>Conclusion</p> <p>We conclude that DNA extracted from FTA cards by the GenSolve kit is of sufficiently high quality to produce results comparable to those obtained from DNA extracted from whole blood when assayed by the Illumina iSelect technology. Additionally, we validate the use of nasal swabs as an alternative to venous blood or buccal samples from animal subjects for reliably producing high quality genotypes on this platform.</p
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