3,494 research outputs found

    Peroxisome proliferator-activated receptor delta limits the expansion of pathogenic Th cells during central nervous system autoimmunity.

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    Peroxisome proliferator-activated receptors (PPARs; PPAR-alpha, PPAR-delta, and PPAR-gamma) comprise a family of nuclear receptors that sense fatty acid levels and translate this information into altered gene transcription. Previously, it was reported that treatment of mice with a synthetic ligand activator of PPAR-delta, GW0742, ameliorates experimental autoimmune encephalomyelitis (EAE), indicating a possible role for this nuclear receptor in the control of central nervous system (CNS) autoimmune inflammation. We show that mice deficient in PPAR-delta (PPAR-delta(-/-)) develop a severe inflammatory response during EAE characterized by a striking accumulation of IFN-gamma(+)IL-17A(-) and IFN-gamma(+)IL-17A(+) CD4(+) cells in the spinal cord. The preferential expansion of these T helper subsets in the CNS of PPAR-delta(-/-) mice occurred as a result of a constellation of immune system aberrations that included higher CD4(+) cell proliferation, cytokine production, and T-bet expression and enhanced expression of IL-12 family cytokines by myeloid cells. We also show that the effect of PPAR-delta in inhibiting the production of IFN-gamma and IL-12 family cytokines is ligand dependent and is observed in both mouse and human immune cells. Collectively, these findings suggest that PPAR-delta serves as an important molecular brake for the control of autoimmune inflammation

    Modelling of Dewatering and Desalting Processes for Large-capacity Oil Treatment Technology

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    This paper is devoted to analysis of oil treatment technology in the case of complex industrial process realization and further selection of technological mode. Mathematical modelling method is used to improve the efficiency of dewatering and desalting processes. The simulation system based on module modelling principle is developed. Every module is described in terms of appropriate combination of phenomena and processes. Problems of oil treatment analysis of complex structured technological scheme and searching of effective dewatering and desalting processes technological modes are solved

    The Retroviral Restriction Ability of SAMHD1, but Not Its Deoxynucleotide Triphosphohydrolase Activity, Is Regulated by Phosphorylation

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    SummarySAMHD1 is a cellular enzyme that depletes intracellular deoxynucleoside triphosphates (dNTPs) and inhibits the ability of retroviruses, notably HIV-1, to infect myeloid cells. Although SAMHD1 is expressed in both cycling and noncycling cells, the antiviral activity of SAMHD1 is limited to noncycling cells. We determined that SAMHD1 is phosphorylated on residue T592 in cycling cells but that this phosphorylation is lost when cells are in a noncycling state. Reverse genetic experiments revealed that SAMHD1 phosphorylated on residue T592 is unable to block retroviral infection, but this modification does not affect the ability of SAMHD1 to decrease cellular dNTP levels. SAMHD1 contains a target motif for cyclin-dependent kinase 1 (cdk1) (592TPQK595), and cdk1 activity is required for SAMHD1 phosphorylation. Collectively, these findings indicate that phosphorylation modulates the ability of SAMHD1 to block retroviral infection without affecting its ability to decrease cellular dNTP levels

    Refractory Materials for Flame Deflector Protection System Corrosion Control: Flame Deflector Protection System Life Cycle Cost Analysis Report

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    A 20-year life cycle cost analysis was performed to compare the operational life cycle cost, processing/turnaround timelines, and operations manpower inspection/repair/refurbishment requirements for corrosion protection of the Kennedy Space Center launch pad flame deflector associated with the existing cast-in-place materials and a newer advanced refractory ceramic material. The analysis compared the estimated costs of(1) continuing to use of the current refractory material without any changes; (2) completely reconstructing the flame trench using the current refractory material; and (3) completely reconstructing the flame trench with a new high-performance refractory material. Cost estimates were based on an analysis of the amount of damage that occurs after each launch and an estimate of the average repair cost. Alternative 3 was found to save 32Mcomparedtoalternative1and32M compared to alternative 1 and 17M compared to alternative 2 over a 20-year life cycle

    Beta defensin-2 is reduced in central but not in distal airways of smoker COPD patients

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    Background: Altered pulmonary defenses in chronic obstructive pulmonary disease (COPD) may promote distal airways bacterial colonization. The expression/activation of Toll Like receptors (TLR) and beta 2 defensin (HBD2) release by epithelial cells crucially affect pulmonary defence mechanisms. Methods: The epithelial expression of TLR4 and of HBD2 was assessed in surgical specimens from current smokers COPD (s-COPD; n = 17), ex-smokers COPD (ex-s-COPD; n = 8), smokers without COPD (S; n = 12), and from non-smoker non-COPD subjects (C; n = 13). Results: In distal airways, s-COPD highly expressed TLR4 and HBD2. In central airways, S and s-COPD showed increased TLR4 expression. Lower HBD2 expression was observed in central airways of s-COPD when compared to S and to ex-s-COPD. s-COPD had a reduced HBD2 gene expression as demonstrated by real-time PCR on micro-dissected bronchial epithelial cells. Furthermore, HBD2 expression positively correlated with FEV1/FVC ratio and inversely correlated with the cigarette smoke exposure. In a bronchial epithelial cell line (16 HBE) IL-1β significantly induced the HBD2 mRNA expression and cigarette smoke extracts significantly counteracted this IL-1 mediated effect reducing both the activation of NFkB pathway and the interaction between NFkB and HBD2 promoter. Conclusions: This study provides new insights on the possible mechanisms involved in the alteration of innate immunity mechanisms in COPD. © 2012 Pace et al

    The APOGEE-2 Survey of the Orion Star Forming Complex: I. Target Selection and Validation with early observations

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    The Orion Star Forming Complex (OSFC) is a central target for the APOGEE-2 Young Cluster Survey. Existing membership catalogs span limited portions of the OSFC, reflecting the difficulty of selecting targets homogeneously across this extended, highly structured region. We have used data from wide field photometric surveys to produce a less biased parent sample of young stellar objects (YSOs) with infrared (IR) excesses indicative of warm circumstellar material or photometric variability at optical wavelengths across the full 420 square degrees extent of the OSFC. When restricted to YSO candidates with H < 12.4, to ensure S/N ~100 for a six visit source, this uniformly selected sample includes 1307 IR excess sources selected using criteria vetted by Koenig & Liesawitz and 990 optical variables identified in the Pan-STARRS1 3π\pi survey: 319 sources exhibit both optical variability and evidence of circumstellar disks through IR excess. Objects from this uniformly selected sample received the highest priority for targeting, but required fewer than half of the fibers on each APOGEE-2 plate. We fill the remaining fibers with previously confirmed and new color-magnitude selected candidate OSFC members. Radial velocity measurements from APOGEE-1 and new APOGEE-2 observations taken in the survey's first year indicate that ~90% of the uniformly selected targets have radial velocities consistent with Orion membership.The APOGEE-2 Orion survey will include >1100 bona fide YSOs whose uniform selection function will provide a robust sample for comparative analyses of the stellar populations and properties across all sub-regions of Orion.Comment: Accepted for publication in ApJ

    Observational Bounds on Cosmic Doomsday

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    Recently it was found, in a broad class of models, that the dark energy density may change its sign during the evolution of the universe. This may lead to a global collapse of the universe within the time t_c ~ 10^{10}-10^{11} years. Our goal is to find what bounds on the future lifetime of the universe can be placed by the next generation of cosmological observations. As an example, we investigate the simplest model of dark energy with a linear potential V(\phi) =V_0(1+\alpha\phi). This model can describe the present stage of acceleration of the universe if \alpha is small enough. However, eventually the field \phi rolls down, V(\phi) becomes negative, and the universe collapses. The existing observational data indicate that the universe described by this model will collapse not earlier than t_c > 10 billion years from the present moment. We show that the data from SNAP and Planck satellites may extend the bound on the "doomsday" time to t_c > 40 billion years at the 95% confidence level.Comment: 11 pages, 6 figures, revtex

    Screening the PRISM Library against Staphylococcus aureus Reveals a Sesquiterpene Lactone from Liriodendron tulipifera with Inhibitory Activity

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    Infections caused by the bacterium Staphylococcus aureus continue to pose threats to human health and put a financial burden on the healthcare system. The overuse of antibiotics has contributed to mutations leading to the emergence of methicillin-resistant S. aureus, and there is a critical need for the discovery and development of new antibiotics to evade drug-resistant bacteria. Medicinal plants have shown promise as sources of new small-molecule therapeutics with potential uses against pathogenic infections. The principal Rhode Island secondary metabolite (PRISM) library is a botanical extract library generated from specimens in the URI Youngken Medicinal Garden by upper-division undergraduate students. PRISM extracts were screened for activity against strains of methicillin-susceptible S. aureus (MSSA). An extract generated from the tulip tree (Liriodendron tulipifera) demonstrated growth inhibition against MSSA, and a bioassay-guided approach identified a sesquiterpene lactone, laurenobiolide, as the active constituent. Intriguingly, its isomers, tulipinolide and epi-tulipinolide, lacked potent activity against MSSA. Laurenobiolide also proved to be more potent against MSSA than the structurally similar sesquiterpene lactones, costunolide and dehydrocostus lactone. Laurenobiolide was the most abundant in the twig bark of the tulip tree, supporting the twig bark’s historical and cultural usage in poultices and teas

    Highly Contiguous Assemblies of 101 Drosophilid Genomes

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    Over 100 years of studies in Drosophila melanogaster and related species in the genus Drosophila have facilitated key discoveries in genetics, genomics, and evolution. While high-quality genome assemblies exist for several species in this group, they only encompass a small fraction of the genus. Recent advances in long-read sequencing allow high-quality genome assemblies for tens or even hundreds of species to be efficiently generated. Here, we utilize Oxford Nanopore sequencing to build an open community resource of genome assemblies for 101 lines of 93 drosophilid species encompassing 14 species groups and 35 sub-groups. The genomes are highly contiguous and complete, with an average contig N50 of 10.5 Mb and greater than 97% BUSCO completeness in 97/101 assemblies. We show that Nanopore-based assemblies are highly accurate in coding regions, particularly with respect to coding insertions and deletions. These assemblies, along with a detailed laboratory protocol and assembly pipelines, are released as a public resource and will serve as a starting point for addressing broad questions of genetics, ecology, and evolution at the scale of hundreds of species
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