206 research outputs found

    Post-Fire Assessment of Prestressed Concrete Bridges in Indiana

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    This project focused on evaluating the effects of fire-induced damage on concrete bridge elements, including prestressed concrete bridge girders. A series of controlled heating experiments, pool fire tests, material tests, and structural loading tests were conducted. Experimental results indicate that the portion of concrete subjected to temperatures higher than 400°C loses significant amounts of calcium hydroxide (CH). Decomposition of CH increases porosity and causes significant cracking. The portion of concrete exposed to temperatures higher than 400°C should be repaired or replaced. When subjected to ISO-834 standard fire heating, approximately 0.25 in. and 0.75 in. of concrete from the exposed surface are damaged after 40 minutes and 80 minutes of heating, respectively. Prestressed concrete girders exposed to about 50 minutes of hydrocarbon fire undergo superficial concrete material damage with loss of CH and extensive cracking and spalling extending to the depth of 0.75–1.0 in. from the exposed surface. These girders do not undergo significant reduction in flexural strength or shear strength. The reduction in the initial stiffness may be notable due to concrete cracking and spalling. Bridge inspectors can use these findings to infer the extent of material and structural damage to prestressed concrete bridge girders in the event of a fire and develop a post-fire assessment plan

    Carbon supported CdSe nanocrystals

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    Insights to the mechanism of CdSe nanoparticle attachment to carbon nanotubes following the hot injection method are discussed. It was observed that the presence of water improves the nanotube coverage while Cl containing media are responsible for the shape transformation of the nanoparticles and further attachment to the carbon lattice. The experiments also show that the mechanism taking place involves the right balance of several factors, namely, low passivated nanoparticle surface, particles with well-defined crystallographic facets, and interaction with an organics-free sp2 carbon lattice. Furthermore, this procedure can be extended to cover graphene by quantum dots.Comment: 5 pages, 5 figure

    Dissecting distinct proteolytic activities of FMDV Lpro implicates cleavage and degradation of RLR signaling proteins, not its deISGylase/DUB activity, in type I interferon suppression

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    Author summary Outbreaks of the picornavirus foot-and-mouth disease virus (FMDV) have significant consequences for animal health and product safety and place a major economic burden on the global livestock industry. Understanding how this notorious animal pathogen suppresses the antiviral type I interferon (IFN-alpha/beta) response may help to develop countermeasures to control FMDV infections. FMDV suppresses the IFN-alpha/beta response through the activity of its Leader protein (L-pro), a protease that can cleave host cell proteins. L(pro)was also shown to have deubiquitinase and deISGylase activity, raising the possibility that L(pro)suppresses IFN-alpha/beta by removing ubiquitin and/or ISG15, two posttranslational modifications that can regulate the activation, interactions and localization of (signaling) proteins. Here, we show that TBK1 and MAVS, two signaling proteins that are important for activation of IFN-alpha/beta gene transcription, are cleaved by L-pro. By generating L(pro)mutants lacking either of these two activities, we demonstrate that L-pro's ability to cleave signaling proteins, but not its deubiquitination/deISGylase activity, correlates with suppression of IFN-beta gene transcription. The type I interferon response is an important innate antiviral pathway. Recognition of viral RNA by RIG-I-like receptors (RLRs) activates a signaling cascade that leads to type I interferon (IFN-alpha/beta) gene transcription. Multiple proteins in this signaling pathway (e.g. RIG-I, MDA5, MAVS, TBK1, IRF3) are regulated by (de)ubiquitination events. Most viruses have evolved mechanisms to counter this antiviral response. The leader protease (L-pro) of foot-and-mouth-disease virus (FMDV) has been recognized to reduce IFN-alpha/beta gene transcription; however, the exact mechanism is unknown. The proteolytic activity of L(pro)is vital for releasing itself from the viral polyprotein and for cleaving and degrading specific host cell proteins, such as eIF4G and NF-kappa B. In addition, L(pro)has been demonstrated to have deubiquitination/deISGylation activity. L-pro's deubiquitination/deISGylation activity and the cleavage/degradation of signaling proteins have both been postulated to be important for reduced IFN-alpha/beta gene transcription. Here, we demonstrate that TBK1, the kinase that phosphorylates and activates the transcription factor IRF3, is cleaved by L(pro)in FMDV-infected cells as well as in cells infected with a recombinant EMCV expressing L-pro.In vitrocleavage experiments revealed that L(pro)cleaves TBK1 at residues 692-694. We also observed cleavage of MAVS in HeLa cells infected with EMCV-L-pro, but only observed decreasing levels of MAVS in FMDV-infected porcine LFPK alpha V beta 6 cells. We set out to dissect L-pro's ability to cleave RLR signaling proteins from its deubiquitination/deISGylation activity, to determine their relative contributions to the reduction of IFN-alpha/beta gene transcription. The introduction of specific mutations, of which several were based on the recently published structure of L(pro)in complex with ISG15, allowed us to identify specific amino acid substitutions that separate the different proteolytic activities of L-pro. Characterization of the effects of these mutations revealed that L-pro's ability to cleave RLR signaling proteins but not its deubiquitination/deISGylation activity correlates with the reduced IFN-beta gene transcription

    Electrical Quality Assurance of the Superconducting Circuits during LHC Machine Assembly

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    Based on the LHC powering reference database, all-together 1750 superconducting circuits were connected in the various cryogenic transfer lines of the LHC machine. Testing the continuity, magnet polarity, and the quality of the electrical insulation were the main tasks of the Electrical Quality Assurance (ELQA) activities during the LHC machine assembly. With the assembly of the LHC now complete, the paper reviews the work flow, resources, and the qualification results including the different types of electrical non-conformities

    Regulatory T-Cells and Associated Pathways in Metastatic Renal Cell Carcinoma (mRCC) Patients Undergoing DC-Vaccination and Cytokine-Therapy

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    Purpose: To evaluate CD4+CD25+FOXP3+ T regulatory cells (TREG) and associated immune-regulatory pathways in peripheral blood lymphocytes (PBL) of metastatic renal cell carcinoma (mRCC) patients and healthy volunteers. We subsequently investigated the effects of immunotherapy on circulating TREG combining an extensive phenotype examination, DNA methylation analysis and global transcriptome analysis. Design: Eighteen patients with mRCC and twelve volunteers (controls) were available for analysis. TREG phenotype was examined using flow cytometry (FCM). TREG were also quantified by analyzing the epigenetic status of the FOXP3 locus using methylation specific PCR. As a third approach, RNA of the PBL was hybridized to Affymetrix GeneChip Human Gene 1.0 ST Arrays and the gene signatures were explored using pathway analysis. Results We observed higher numbers of TREG in pre-treatment PBL of mRCC patients compared to controls. A significant increase in TREG was detected in all mRCC patients after the two cycles of immunotherapy. The expansion of TREG was significantly higher in non-responders than in responding patients. Methylation specific PCR confirmed the FCM data and circumvented the variability and subjectivity of the FCM method. Gene Set Enrichment Analysis (GSEA) of the microarray data showed significant enrichment of FOXP3 target genes, CTLA-4 and TGF-ß associated pathways in the patient cohort. Conclusion: Immune monitoring of the peripheral blood and tumor tissue is important for a wide range of diseases and treatment strategies. Adoption of methodology for quantifying TREG with the least variability and subjectivity will enhance the ability to compare and interpret findings across studies

    Tracing ancestry with methylation patterns: most crypts appear distantly related in normal adult human colon

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    BACKGROUND: The ability to discern ancestral relationships between individual human colon crypts is limited. Widely separated crypts likely trace their common ancestors to a time around birth, but closely spaced adult crypts may share more recent common ancestors if they frequently divide by fission to form clonal patches. Alternatively, adult crypts may be long-lived structures that infrequently divide or die. METHODS: Methylation patterns (the 5' to 3' order of methylation) at CpG sites that exhibit random changes with aging were measured from isolated crypts by bisulfite genomic sequencing. This epigenetic drift may be used to infer ancestry because recently related crypts should have similar methylation patterns. RESULTS: Methylation patterns were different between widely separated ("unrelated") crypts greater than 15 cm apart. Evidence for a more recent relationship between directly adjacent or branched crypts could not be found because their methylation pattern distances were not significantly different than widely separated crypt pairs. Methylation patterns are essentially equally different between two adult human crypts regardless of their relative locations. CONCLUSIONS: Methylation patterns appear to record somatic cell trees. Starting from a single cell at conception, sequences replicate and may drift apart. Most adult human colon crypts appear to be long-lived structures that become mosaic with respect to methylation during aging

    Risk factors for Epstein–Barr virus reactivation after renal transplantation: Results of a large, multi‐centre study

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    Epstein-Barr virus (EBV) reactivation is a very common and potentially lethal complication of renal transplantation. However, its risk factors and effects on transplant outcome are not well known. Here, we have analysed a large, multi-centre cohort (N = 512) in which 18.4% of the patients experienced EBV reactivation during the first post-transplant year. The patients were characterized pre-transplant and two weeks post-transplant by a multi-level biomarker panel. EBV reactivation was episodic for most patients, only 12 patients showed prolonged viraemia for over four months. Pre-transplant EBV shedding and male sex were associated with significantly increased incidence of post-transplant EBV reactivation. Importantly, we also identified a significant association of post-transplant EBV with acute rejection and with decreased haemoglobin levels. No further severe complications associated with EBV, either episodic or chronic, could be detected. Our data suggest that despite relatively frequent EBV reactivation, it had no association with serious complications during the first post-transplantation year. EBV shedding prior to transplantation could be employed as biomarkers for personalized immunosuppressive therapy. In summary, our results support the employed immunosuppressive regimes as relatively safe with regard to EBV. However, long-term studies are paramount to support these conclusions

    Allele-specific demethylation at an imprinted mammalian promoter

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    A screen for imprinted genes on mouse Chromosome 7 recently identified Inpp5f_v2, a paternally expressed retrogene lying within an intron of Inpp5f. Here, we identify a novel paternally expressed variant of the Inpp5f gene (Inpp5f_v3) that shows a number of unusual features. Inpp5f_v3 initiates from a CpG-rich repeat region adjoining two B1 elements, despite previous reports that SINEs are generally excluded from imprinted promoters. Accordingly, we find that the Inpp5f_v3 promoter acquires methylation around the time of implantation, when many repeat families undergo de novo epigenetic silencing. Methylation is then lost specifically on the paternally derived allele during the latter stages of embryonic development, resulting in imprinted transcriptional activation on the demethylated allele. Methylation analyses in embryos lacking maternal methylation imprints suggest that the primary imprinting mark resides within an intronic CpG island ∼1 kb downstream of the Inpp5f_v3 transcriptional start site. These data support the hypothesis that SINEs can influence gene expression by attracting de novo methylation during development, a property likely to explain their exclusion from other imprinted promoters

    Patterns of Hybrid Loss of Imprinting Reveal Tissue- and Cluster-Specific Regulation

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    Background: Crosses between natural populations of two species of deer mice, Peromyscus maniculatus (BW), and P. polionotus (PO), produce parent-of-origin effects on growth and development. BW females mated to PO males (bw6po) produce growth-retarded but otherwise healthy offspring. In contrast, PO females mated to BW males (PO6BW) produce overgrown and severely defective offspring. The hybrid phenotypes are pronounced in the placenta and include PO6BW conceptuses which lack embryonic structures. Evidence to date links variation in control of genomic imprinting with the hybrid defects, particularly in the PO6BW offspring. Establishment of genomic imprinting is typically mediated by gametic DNA methylation at sites known as gDMRs. However, imprinted gene clusters vary in their regulation by gDMR sequences. Methodology/Principal Findings: Here we further assess imprinted gene expression and DNA methylation at different cluster types in order to discern patterns. These data reveal PO6BW misexpression at the Kcnq1ot1 and Peg3 clusters, both of which lose ICR methylation in placental tissues. In contrast, some embryonic transcripts (Peg10, Kcnq1ot1) reactivated the silenced allele with little or no loss of DNA methylation. Hybrid brains also display different patterns of imprinting perturbations. Several cluster pairs thought to use analogous regulatory mechanisms are differentially affected in the hybrids. Conclusions/Significance: These data reinforce the hypothesis that placental and somatic gene regulation differs significantly, as does that between imprinted gene clusters and between species. That such epigenetic regulatory variatio

    Regulatory T-Cells and Associated Pathways in Metastatic Renal Cell Carcinoma (mRCC) Patients Undergoing DC-Vaccination and Cytokine-Therapy

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    To evaluate CD4(+)CD25(+)FOXP3(+) T regulatory cells (T(REG)) and associated immune-regulatory pathways in peripheral blood lymphocytes (PBL) of metastatic renal cell carcinoma (mRCC) patients and healthy volunteers. We subsequently investigated the effects of immunotherapy on circulating T(REG) combining an extensive phenotype examination, DNA methylation analysis and global transcriptome analysis
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