824 research outputs found

    Study on Application of Diacetylene- containing Copolyurethanes (DA-coPUs) coating as strain sensors using Raman Spectroscopy

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    A two-phase copolymer DA-coPUs containing of 50% hard-segment has been prepared using a polyoxypropylene-diol with molecular weight of 2000 (Voranol 2000), 4,4 -diphenylmethane diisocyanate(MDI) and 2,4-hexadiyne-1,6-diol (HDD) via a one-shot, bulk polymerization process. Solution of linear, as-prepared DA-coPUs in N,N-Dimethylacetamide (DMAc) was coated onto pre-heated steel beam. Cross polymerization of the DA-coPUs were carried out using heating under nitrogen at 100â—¦C for 5 hours. Deformation micromechanics of the DA-coPUs has been studied using simultaneous 4-point bending testing and Raman spectroscopy. The results showed that the coating has poorer strain- induced Raman band shift factors than that of pure DA-coPUs [1

    Hyperactivity in the Gunn rat model of neonatal jaundice: age-related attenuation and emergence of gait deficits

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    Background Neonatal jaundice resulting from elevated unconjugated bilirubin (UCB) occurs in 60–80% of newborn infants. Although mild jaundice is generally considered harmless, little is known about its long-term consequences. Recent studies have linked mild bilirubin-induced neurological dysfunction (BIND) with a range of neurological syndromes, including attention deficit-hyperactivity disorder. The goal of this study was to measure BIND across the lifespan in the Gunn rat model of BIND. Methods Using a sensitive force plate actometer, we measured locomotor activity and gait in jaundiced (jj) Gunn rats versus their non-jaundiced (Nj) littermates. Data were analyzed for young adult (3–4 months), early middle-aged (9–10 months), and late middle-aged (17–20 months) male rats. Results jj rats exhibited lower body weights at all ages and a hyperactivity that resolved at 17–20 months of age. Increased propulsive force and gait velocity accompanied hyperactivity during locomotor bouts at 9–10 months in jj rats. Stride length did not differ between the two groups at this age. Hyperactivity normalized and gait deficits, including decreased stride length, propulsive force, and gait velocity, emerged in the 17–20-month-old jj rats. Conclusions These results demonstrate that, in aging, hyperactivity decreases with the onset of gait deficits in the Gunn rat model of BIND

    E-Manufacturing for product improvement at Red Bull technology

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    In Formula 1 racing, there is a strong motive for reducing component weight and thereby improving efficiency. This paper demonstrates the advantages e-Manufacturing brings to the production of hydraulic components. The DMLS production technique would enable weight reductions to be attained by its geometric design freedom coupled with this material’s attributes. The use of EOS Titanium Ti64 material for hydraulic components has been assessed by a hydraulic soak test at 25 MPa and no significant losses or failure occurred. The benefits to the efficiency of hydraulic flow have been measured using Particle Image Velocimetry (PIV) and the use of DMLS designed geometry has improved flow characteristics by 250% over that of the currently used techniques of manufacturing channels and bores

    Abundances on the Main Sequence of Omega Centauri

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    Abundance ratios of carbon, nitrogen and strontium relative to iron, calculated using spectrum synthesis techniques, are given for a sample of main sequence and turnoff stars that belong to the globular cluster omega Centauri. The variations of carbon, nitrogen and/or strontium show several different abundance patterns as a function of [Fe/H]. The source of the enhancements/depletions in carbon, nitrogen and/or strontium may be enrichment from asymptotic giant branch stars of low (1--3 solar masses) and intermediate (3--8 solar masses) mass. Massive rotating stars which produce excess nitrogen without carbon and oxygen overabundances may also play a role. These abundances enable different contributors to be considered and incorporated into the evolutionary picture of omega Cen.Comment: 43 Pages, 13 Figures. Accepted for publication in Ap

    Short Term Development and Fate of MGE-Like Neural Progenitor Cells in Jaundiced and Non-Jaundiced Rat Brain

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    A grant from the One-University Open Access Fund at the University of Kansas was used to defray the author's publication fees in this Open Access journal. The Open Access Fund, administered by librarians from the KU, KU Law, and KUMC libraries, is made possible by contributions from the offices of KU Provost, KU Vice Chancellor for Research & Graduate Studies, and KUMC Vice Chancellor for Research. For more information about the Open Access Fund, please see http://library.kumc.edu/authors-fund.xml.Neonatal hyperbilirubinemia targets specific brain regions and can lead to kernicterus. One of the most debilitating symptoms of kernicterus is dystonia, which results from bilirubin toxicity to the globus pallidus (GP). Stem cell transplantation into the GP to replace lost neurons and restore basal ganglia circuits function is a potential therapeutic strategy to treat dystonia in kernicterus. In this study we transplanted human medial ganglionic eminence (MGE)-like neural progenitor cells (NPCs) that we differentiated into a primarily gamma-aminobutyric acid (GABA)ergic phenotype, into the GP of non-immunosuppressed jaundiced (jj) and non-jaundiced (Nj) rats. We assessed the survival and development of graft cells at three time-points post-transplantation. While grafted MGE-like NPCs survived and generated abundant fibers in both jj and Nj brains, NPC survival was greater in the jj brain. These results were consistent with our previous finding that excitatory spinal interneuron-like NPCs exhibited a higher survival rate in the jj brain than in the Nj brain. Our findings further support our hypothesis that slightly elevated bilirubin levels in the jj brain served as an antioxidant and immunosuppressant to protect the transplanted cells. We also identified graft fibers growing toward brain regions that receive projections from the GP, as well as host fibers extending toward the graft. These promising findings suggest that MGE-like NPCs may have the capacity to restore the circuits connecting GP and other nuclei.NIH Center of Biomedical Research Excellence program project P20 GM104936Children's Mercy HospitalRonald D. Deffenbaugh FoundationKansas Intellectual and Developmental Disabilities Research Center HD09021

    Within-Session Analysis of Amphetamine-Elicited Rotation Behavior Reveals Differences between Young Adult and Middle-Aged F344/BN Rats with Partial Unilateral Striatal Dopamine Depletion

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    Preclinical modeling of Parkinson's disease using 6-hydroxydopamine (6-OHDA) has been valuable in developing and testing therapeutic strategies. Recent efforts have focused on modeling early stages of disease by infusing 6-OHDA into the striatum. The partial DA depletion that follows intrastriatal 6-OHDA is more variable than the near complete depletion following medial forebrain bundle infusion, and behavioral screening assays are not as well characterized in the partial lesion model. We compared relationships between amphetamine-elicited rotation behavior and DA depletion following intrastriatal 6-OHDA (12.5 μg) in 6 month vs. 18 month F344/BN rats, at 2-weeks and 6-weeks post-lesion. We compared the total number of rotations with within-session (bin-by-bin) parameters of rotation behavior as indicators of DA depletion. Striatal DA depletion was greater in the young adult than in the middle-aged rats at 2 weeks but not at 6 weeks post-lesion. The total number of rotations for the whole session and striatal DA depletion did not differ between the two age groups. Regression analysis revealed a greater relationship between within-session parameters of rotation behavior and DA depletion in the middle-aged group than in the young adult group. These results have implications for estimating DA depletion in preclinical studies using rats of different ages
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