1,650 research outputs found

    Amino acid intake & body protein synthesis

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    Cover title."Lecture presented Feb. 7, 1967, at the University of Missouri-Columbia"--P. 4.Includes bibliographical references (pages 23-24)

    Proton configurations in the hydrogen bonds of KH2PO4 as seen by resonant x-ray diffraction

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    KH2PO4 (KDP) belongs to the class of hydrogen-bonded ferroelectrics, whose paraelectric to ferroelectric phase transition is driven by the ordering of the protons in the hydrogen bonds. We demonstrate that forbidden reflections of KDP, when measured at an x-ray absorption edge, are highly sensitive to the asymmetry of proton configurations. The change of average symmetry caused by the "freezing" of the protons during the phase transition is clearly evidenced. In the paraelectric phase, we identify in the resonant spectra of the forbidden reflections a contribution related to the transient proton configurations in the hydrogen bonds, which violates the high average symmetry of the sites of the resonant atoms. The analysis of the temperature dependence reveals a change of relative probabilities of the different proton configurations. They follow the Arrhenius law, and the activation energies of polar and Slater configurations are 18.6 and 7.3 meV, respectively

    The Care of the Elderly with Special Reference to Foresthall Institution, Glasgow

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    Abstract Not Provided

    Assessing the effect of broadleaf woodland expansion on acidic dry deposition and streamwater acidification

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    The study aim was to determine whether enhanced dry deposition of acidic atmospheric pollutants by broadleaf woodland expansion could increase the potential for acidification of surface waters in acid-sensitive areas. Dry sulphur (S) and nitrogen (N) deposition was modelled with the Fine Resolution Atmospheric Multi-pollutant Exchange (FRAME) model using a roughness length value calculated specifically for birchwoods. Two scenarios were investigated for an acid-sensitive area in Scotland where broadleaf woodland expansion, mainly as birchwood, is occurring: (1) 2002 emissions and broadleaf woodland cover of 5.6%; (2) 2020 projected emissions and broadleaf cover of 29%. The roughness length calculated for birch with Raupach's simplified drag-partition model was 0.73 m, lower than the value of 1.0 m for conifers which is the default for forest land cover in FRAME. Modelled dry S and N deposition increased between 2002 and 2020 from 8.7 to 29 x 10(-3) keq ha(-1) year(-1) of H(+). However, modelled total dry and wet non-marine S and N deposition decreased during the same period from 1070 to 682 x 10(-3) keq ha(-1) year(-1) of H(+) due to the lower projected emissions in 2020 and the dominance of wet deposition in the remote and upland study area (mean annual rainfall 2275 mm). The modelled total non-marine S and N deposition was used to calculate streamwater critical loads exceedance with the First-order Acidity Balance (FAB) model for five catchments in the study area. The modelled deposition for both the 2002 and 2020 scenarios was less than the calculated streamwater critical loads so the catchments were not considered at risk of streamwater acidification under the projected future emissions and increased broadleaf woodland cover. Nevertheless, broadleaf expansion could pose a greater risk of acidification in acid-sensitive areas with lower rainfall, closer to pollutant sources, where dry deposition accounts for a higher proportion of total S and N deposition. (C) 2011 Elsevier B.V. All rights reserved

    A comparative study on the effect of subtherapeutic tylosin administration on select feral or domestic porcine gut microflora grown in continuous-flow culture

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    Continuous now cultures of feral (culture FC) and domesticated (culture RPCF) pig gut microflora were established in steady state. Cultures, in duplicate, were continuously infused subtherapeutic (2S lJg/ml) levels of tylosin and sampled at intervals to assess effects on total culturable anaerobes, Bacteroides spp. and Enterococcus spp. via plating on serial 10-fold dilutions to anaerobic Brucella blood agar, Bacteroides bile esculin agar, and M Enterococcus agar supplemented without or with 100 lJg tylosin/ml, the later to assess bacterial sensitivity to tylosin Concentrations of total culturable anaerobes within culture FC decreased (P \u3c 0.05), albeit slightly, following 7 days tylosin administration. Concentrations of Bacteroides and Enterococcus decreased (P \u3c 0.05) to near or below detectable levels (1.0 log10 CFU/ml) in culture FC following 7 days tylosin administration, and tylosin-insensitive colonies were recovered at low numbers (~ 2 log10 CFU/ml) and did not persist

    Endogenous Quasicycles and Stochastic Coherence in a Closed Endemic Model

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    We study the role of demographic fluctuations in typical endemics as exemplified by the stochastic SIRS model. The birth-death master equation of the model is simulated using exact numerics and analysed within the linear noise approximation. The endemic fixed point is unstable to internal demographic noise, and leads to sustained oscillations. This is ensured when the eigenvalues (λ\lambda) of the linearised drift matrix are complex, which in turn, is possible only if detailed balance is violated. In the oscillatory state, the phases decorrelate asymptotically, distinguishing such oscillations from those produced by external periodic forcing. These so-called quasicycles are of sufficient strength to be detected reliably only when the ratio ∣Im(λ)/Re(λ)∣|Im(\lambda)/Re(\lambda)| is of order unity. The coherence or regularity of these oscillations show a maximum as a function of population size, an effect known variously as stochastic coherence or coherence resonance. We find that stochastic coherence can be simply understood as resulting from a non-monotonic variation of ∣Im(λ)/Re(λ)∣|Im(\lambda)/Re(\lambda)| with population size. Thus, within the linear noise approximation, stochastic coherence can be predicted from a purely deterministic analysis. The non-normality of the linearised drift matrix, associated with the violation of detailed balance, leads to enhanced fluctuations in the population amplitudes.Comment: 21 pages, 8 figure

    Ultra-Porous Nanoparticle Networks: A Biomimetic Coating Morphology for Enhanced Cellular Response and Infiltration

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    Orthopedic treatments are amongst the most common cause of surgery and are responsible for a large share of global healthcare expenditures. Engineering materials that can hasten bone integration will improve the quality of life of millions of patients per year and reduce associated medical costs. Here, we present a novel hierarchical biomimetic coating that mimics the inorganic constituent of mammalian bones with the aim of improving osseointegration of metallic implants. We exploit the thermally-driven self-organization of metastable core-shell nanoparticles during their aerosol self-assembly to rapidly fabricate robust, ultra-porous nanoparticle networks (UNN) of crystalline hydroxyapatite (HAp). Comparative analysis of the response of osteoblast cells to the ultra-porous nanostructured HAp surfaces and to the spin coated HAp surfaces revealed superior osseointegrative properties of the UNN coatings with significant cell and filopodia infiltration. This flexible synthesis approach for the engineering of UNN HAp coatings on titanium implants provides a platform technology to study the bone-implant interface for improved osseointegration and osteoconduction
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