676 research outputs found

    Hubble-COS Observations of Galactic High-Velocity Clouds: Four AGN Sight Lines through Complex C

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    We report ultraviolet spectra of Galactic high-velocity clouds (HVCs) in Complex C, taken by the Cosmic Origins Spectrograph (COS) on the Hubble Space Telescope (HST), together with new 21-cm spectra from the Green Bank Telescope. The wide spectral coverage and higher S/N, compared to previous HST spectra, provide better velocity definition of the HVC absorption, additional ionization species, and improved abundances in this halo gas. Complex C has a metallicity of 0.1-0.3 solar and a wide range of ions, suggesting dynamical and thermal interactions with hot gas in the Galactic halo. Spectra in the COS medium-resolution G130M (1133-1468 A) and G160M (1383-1796 A) gratings detect ultraviolet absorption lines from 8 elements in low ionization stages (O I, N I, C II, S II, Si II, Al II, Fe II, P II) and 3 elements in intermediate and high-ionization states (Si III, Si IV, C IV, N V). Our four AGN sight lines toward Mrk 817, Mrk 290, Mrk 876, and PG1259+593 have high-velocity H I and O VI column densities, log N_HI = 19.39-20.05 and log N_OVI = 13.58-14.10, with substantial amounts of kinematically associated photoionized gas. The high-ion abundance ratios are consistent with cooling interfaces between photoionized gas and collisionally ionized gas: N(C IV)/N(O VI) = 0.3-0.5, N(Si IV)/N(O VI) = 0.05-0.11, N(N V)/N(O VI) = 0.07-0.13, and N(Si IV)/N(Si III) = 0.2.Comment: 43 pages, 11 figures (appearing in ApJ, Sept 1, 2011

    Brazing techniques for the fabrication of biocompatible carbon-based electronic devices

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    Prototype electronic devices have been critical to the discovery and demonstration of the unique properties of new materials, including composites based on carbon nanotubes (CNT) and graphene. However, these devices are not typically constructed with durability or biocompatibility in mind, relying on conductive polymeric adhesives, mechanical clamps or crimps, or solders for electrical connections. In this paper, two key metallization techniques are presented that employ commercially-available brazing alloys to fabricate electronic devices based on diamond and carbonaceous wires. Investigation of the carbon - alloy interfacial interactions was utilized to guide device fabrication. The interplay of both chemical ( adhesive ) and mechanical ( cohesive ) forces at the interface of different forms of carbon was exploited to fabricate either freestanding or substrate-fixed carbonaceous electronic devices. Elemental analysis in conjunction with scanning electron microscopy of the carbon - alloy interface revealed the chemical nature of the Ag alloy bond and the mechanical nature of the Au alloy bond. Electrical characterization revealed the non-rectifying nature of the carbon - Au alloy interconnects. Finally, electronic devices were fabricated, including a Au circuit structure embedded in a polycrystalline diamond substrate

    Porphyromonas gingivalis oral infection exacerbates the development and severity of collagen-induced arthritis

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    Abstract Introduction Clinical studies suggest a direct influence of periodontal disease (PD) on serum inflammatory markers and disease assessment of patients with established rheumatoid arthritis (RA). However, the influence of PD on arthritis development remains unclear. This investigation was undertaken to determine the contribution of chronic PD to immune activation and development of joint inflammation using the collagen-induced arthritis (CIA) model. Methods DBA1/J mice orally infected with Porphyromonas gingivalis were administered with collagen II (CII) emulsified in complete Freund’s adjuvant (CFA) or incomplete Freund’s adjuvant (IFA) to induce arthritis. Arthritis development was assessed by visual scoring of paw swelling, caliper measurement of the paws, mRNA expression, paw micro-computed tomography (micro-CT) analysis, histology, and tartrate resistant acid phosphatase for osteoclast detection (TRAP)-positive immunohistochemistry. Serum and reactivated splenocytes were evaluated for cytokine expression. Results Mice induced for PD and/or arthritis developed periodontal disease, shown by decreased alveolar bone and alteration of mRNA expression in gingival tissues and submandibular lymph nodes compared to vehicle. P. gingivalis oral infection increased paw swelling and osteoclast numbers in mice immunized with CFA/CII. Arthritis incidence and severity were increased by P. gingivalis in mice that received IFA/CII immunizations. Increased synovitis, bone erosions, and osteoclast numbers in the paws were observed following IFA/CII immunizations in mice infected with P gingivalis. Furthermore, cytokine analysis showed a trend toward increased serum Th17/Th1 ratios when P. gingivalis infection was present in mice receiving either CFA/CII or IFA/CII immunizations. Significant cytokine increases induced by P. gingivalis oral infection were mostly associated to Th17-related cytokines of reactivated splenic cells, including IL-1β, IL-6, and IL-22 in the CFA/CII group and IL-1β, tumor necrosis factor-α, transforming growth factor-β, IL-6 and IL-23 in the IFA/CII group. Conclusions Chronic P. gingivalis oral infection prior to arthritis induction increases the immune system activation favoring Th17 cell responses, and ultimately accelerating arthritis development. These results suggest that chronic oral infection may influence RA development mainly through activation of Th17-related pathways.http://deepblue.lib.umich.edu/bitstream/2027.42/112639/1/13075_2013_Article_4062.pd

    Whole-Genome Sequencing-Based Characterization of 100 Listeria monocytogenes Isolates Collected from Food Processing Environments over a Four-Year Period

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    Listeria monocytogenes is frequently found in foods and processing facilities, where it can persist, creating concerns for the food industry. Its ability to survive under a wide range of environmental conditions enhances the potential for cross-contamination of the final food products, leading to possible outbreaks of listeriosis. In this study, whole-genome sequencing (WGS) was applied as a tool to characterize and track 100 L. monocytogenes isolates collected from three food processing environments. These WGS data from environmental and food isolates were analyzed to (i) assess the genomic diversity of L. monocytogenes, (ii) identify possible source(s) of contamination, cross-contamination routes, and persistence, (iii) detect absence/presence of antimicrobial resistance-encoding genes, (iv) assess virulence genotypes, and (v) explore in vivo pathogenicity of selected L. monocytogenes isolates carrying different virulence genotypes. The predominant L. monocytogenes sublineages (SLs) identified were SL101 (21%), SL9 (17%), SL121 (12%), and SL5 (12%). Benzalkonium chloride (BC) tolerance-encoding genes were found in 62% of these isolates, a value that increased to 73% among putative persistent subgroups. The most prevalent gene was emrC followed by bcrABC, qacH-Tn6188, and qacC. The L. monocytogenes major virulence factor inlA was truncated in 31% of the isolates, and only one environmental isolate (L. monocytogenes CFS086) harbored all major virulence factors, including Listeria pathogenicity island 4 (LIPI-4), which has been shown to confer hypervirulence. A zebrafish embryo infection model showed a low (3%) embryo survival rate for all putatively hypervirulent L. monocytogenes isolates assayed. Higher embryo survival rates were observed following infection with unknown virulence potential (20%) and putatively hypovirulent (53 to 83%) L. monocytogenes isolates showing predicted pathogenic phenotypes inferred from virulence genotypes

    A New Rhesus Macaque Assembly and Annotation for Next-Generation Sequencing Analyses

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    BACKGROUND: The rhesus macaque (Macaca mulatta) is a key species for advancing biomedical research. Like all draft mammalian genomes, the draft rhesus assembly (rheMac2) has gaps, sequencing errors and misassemblies that have prevented automated annotation pipelines from functioning correctly. Another rhesus macaque assembly, CR_1.0, is also available but is substantially more fragmented than rheMac2 with smaller contigs and scaffolds. Annotations for these two assemblies are limited in completeness and accuracy. High quality assembly and annotation files are required for a wide range of studies including expression, genetic and evolutionary analyses. RESULTS: We report a new de novo assembly of the rhesus macaque genome (MacaM) that incorporates both the original Sanger sequences used to assemble rheMac2 and new Illumina sequences from the same animal. MacaM has a weighted average (N50) contig size of 64 kilobases, more than twice the size of the rheMac2 assembly and almost five times the size of the CR_1.0 assembly. The MacaM chromosome assembly incorporates information from previously unutilized mapping data and preliminary annotation of scaffolds. Independent assessment of the assemblies using Ion Torrent read alignments indicates that MacaM is more complete and accurate than rheMac2 and CR_1.0. We assembled messenger RNA sequences from several rhesus tissues into transcripts which allowed us to identify a total of 11,712 complete proteins representing 9,524 distinct genes. Using a combination of our assembled rhesus macaque transcripts and human transcripts, we annotated 18,757 transcripts and 16,050 genes with complete coding sequences in the MacaM assembly. Further, we demonstrate that the new annotations provide greatly improved accuracy as compared to the current annotations of rheMac2. Finally, we show that the MacaM genome provides an accurate resource for alignment of reads produced by RNA sequence expression studies. CONCLUSIONS: The MacaM assembly and annotation files provide a substantially more complete and accurate representation of the rhesus macaque genome than rheMac2 or CR_1.0 and will serve as an important resource for investigators conducting next-generation sequencing studies with nonhuman primates. REVIEWERS: This article was reviewed by Dr. Lutz Walter, Dr. Soojin Yi and Dr. Kateryna Makova

    Distinct Binding and Immunogenic Properties of the Gonococcal Homologue of Meningococcal Factor H Binding Protein

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    Neisseria meningitidis is a leading cause of sepsis and meningitis. The bacterium recruits factor H (fH), a negative regulator of the complement system, to its surface via fH binding protein (fHbp), providing a mechanism to avoid complement-mediated killing. fHbp is an important antigen that elicits protective immunity against the meningococcus and has been divided into three different variant groups, V1, V2 and V3, or families A and B. However, immunisation with fHbp V1 does not result in cross-protection against V2 and V3 and vice versa. Furthermore, high affinity binding of fH could impair immune responses against fHbp. Here, we investigate a homologue of fHbp in Neisseria gonorrhoeae, designated as Gonococcal homologue of fHbp (Ghfp) which we show is a promising vaccine candidate for N. meningitidis. We demonstrate that Gfhp is not expressed on the surface of the gonococcus and, despite its high level of identity with fHbp, does not bind fH. Substitution of only two amino acids in Ghfp is sufficient to confer fH binding, while the corresponding residues in V3 fHbp are essential for high affinity fH binding. Furthermore, immune responses against Ghfp recognise V1, V2 and V3 fHbps expressed by a range of clinical isolates, and have serum bactericidal activity against N. meningitidis expressing fHbps from all variant groups

    Azimuthal Angle Correlations for Rapidity Separated Hadron Pairs in d+Au Collisions at sqrt(s_NN) = 200 GeV

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    We report on two-particle azimuthal angle correlations between charged hadrons at forward/backward (deuteron/gold going direction) rapidity and charged hadrons at mid-rapidity in deuteron-gold (d+Au) and proton-proton (p+p) collisions at sqrt(s_NN) = 200 GeV. Jet structures are observed in the correlations which we quantify in terms of the conditional yield and angular width of away side partners. The kinematic region studied here samples partons in the gold nucleus carrying nucleon momentum fraction x~0.1 to x~0.01. Within this range, we find no x dependence of the jet structure in d+Au collisions.Comment: 330 authors, 6 pages text, 4 figures, no tables. Submitted to Phys. Rev. Lett. Plain text data tables for the points plotted in figures for this and previous PHENIX publications are (or will be) publicly available at http://www.phenix.bnl.gov/papers.htm

    Sensory cutaneous papillae in the sea lamprey (Petromyzonmarinus L.) : I. Neuroanatomy and physiology

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    Molecules present in an animal's environment can indicate the presence of predators,food, or sexual partners and consequently, induce migratory, reproductive, foraging,or escape behaviors. Three sensory systems, the olfactory, gustatory, and solitarychemosensory cell (SCC) systems detect chemical stimuli in vertebrates. While agreat deal of research has focused on the olfactory and gustatory system over theyears, it is only recently that significant attention has been devoted to the SCC sys-tem. The SCCs are microvillous cells that were first discovered on the skin of fish,and later in amphibians, reptiles, and mammals. Lampreys also possess SCCs that areparticularly numerous on cutaneous papillae. However, little is known regarding theirprecise distribution, innervation, and function. Here, we show that sea lampreys(Petromyzon marinus L.) have cutaneous papillae located around the oral disk, nostril,gill pores, and on the dorsal fins and that SCCs are particularly numerous on thesepapillae. Tract-tracing experiments demonstrated that the oral and nasal papillae areinnervated by the trigeminal nerve, the gill pore papillae are innervated by branchialnerves, and the dorsal fin papillae are innervated by spinal nerves. We also character-ized the response profile of gill pore papillae to some chemicals and showed thattrout-derived chemicals, amino acids, and a bile acid produced potent responses.Together with a companion study (Suntres et al., Journal of Comparative Neurology,this issue), our results provide new insights on the function and evolution of the SCCsystem in vertebrates

    CD4+ T cell recovery during suppression of HIV replication: an international comparison of the immunological efficacy of antiretroviral therapy in North America, Asia and Africa

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    Background: Even among HIV-infected patients who fully suppress plasma HIV RNA replication on antiretroviral therapy, genetic (e.g. CCL3L1 copy number), viral (e.g. tropism) and environmental (e.g. chronic exposure to microbial antigens) factors influence CD4 recovery. These factors differ markedly around the world and therefore the expected CD4 recovery during HIV RNA suppression may differ globally. Methods: We evaluated HIV-infected adults from North America, West Africa, East Africa, Southern Africa and Asia starting non-nucleoside reverse transcriptase inhibitor-based regimens containing efavirenz or nevirapine, who achieved at least one HIV RNA level <500/µl in the first year of therapy and observed CD4 changes during HIV RNA suppression. We used a piecewise linear regression to estimate the influence of region of residence on CD4 recovery, adjusting for socio-demographic and clinical characteristics. We observed 28 217 patients from 105 cohorts over 37 825 person-years. Results: After adjustment, patients from East Africa showed diminished CD4 recovery as compared with other regions. Three years after antiretroviral therapy initiation, the mean CD4 count for a prototypical patient with a pre-therapy CD4 count of 150/µl was 529/µl [95% confidence interval (CI): 517-541] in North America, 494/µl (95% CI: 429-559) in West Africa, 515/µl (95% CI: 508-522) in Southern Africa, 503/µl (95% CI: 478-528) in Asia and 437/µl (95% CI: 425-449) in East Africa. Conclusions: CD4 recovery during HIV RNA suppression is diminished in East Africa as compared with other regions of the world, and observed differences are large enough to potentially influence clinical outcomes. Epidemiological analyses on a global scale can identify macroscopic effects unobservable at the clinical, national or individual regional leve
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