384 research outputs found

    Temperature prediction in domestic refrigerator: Determinist and stochastic approaches

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    International audienceThe influence of two random variables: ambient temperature and thermostat setting, on air and load temperatures in non ventilated domestic refrigerator was studied. A simplified steady state heat transfer model was developed which takes into account heat exchanges by convection and radiation. This model considers circular airflow due to natural convection inside the cavity. The normal distribution of ambient and thermostat temperatures was developed to fit the survey data. Monte Carlo method was used for a sampling of ambient and thermostat temperatures from this distribution. These values were then used as input parameters of the deterministic model allowing the calculation of air and load temperatures. An analysis of the predicted temperatures was undertaken by comparing with survey data of air and load temperatures in domestic refrigerators in France, a good agreement was obtained. This model can be used as risk evaluation tool

    Semi-classical Laguerre polynomials and a third order discrete integrable equation

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    A semi-discrete Lax pair formed from the differential system and recurrence relation for semi-classical orthogonal polynomials, leads to a discrete integrable equation for a specific semi-classical orthogonal polynomial weight. The main example we use is a semi-classical Laguerre weight to derive a third order difference equation with a corresponding Lax pair.Comment: 11 page

    A Tricky One: Barriers to Non-opioid Pain Management in University Healthcare

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    We explored palliation practices and experiences among providers at university campus health centers to assess the availability and viability of non-opioid options for student patients. We interviewed 10 healthcare providers at the campus health center for a large research university in the southeastern United States. Data were collected via semi- structured interviews. Analyses of interview transcripts were performed via content analysis with open coding. We identified multiple barriers to non-opioid pain management. Non-opioid modalities were more likely to receive no insurance subsidy, and thus, to go unused even if clinically indicated. Providers also reported high levels of concern with potential opioid dependency, as well as interest in safer options for long-term palliation. Contextualizing results from our case study with prior literature from other care settings suggests that lack of access to non-opioid options presents challenges for university students who live with chronic pain

    Prédiction des transferts et de la croissance microbienne lors du transport de carcasses de porcs

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    26eme congrÚs français de thermique, Pau, FRA, 29-/05/2018 - 01/06/2018National audienceLors du transport de carcasses de porcs, plusieurs facteurs influencent l'évolution de la charge microbienne notamment la température et l'activité de l'eau qui dépendent des transferts dechaleur et d'eau au sein et autour des carcasses. Une expérimentation a été réalisée sur une maquette à l'échelle ~1/3 d'un camion frigorifique chargé de carcasses pour déterminer l'hétérogénéité des coefficients de transfert. Un modÚle a ensuite été développé pour simuler les transferts de chaleur et dematiÚre au niveau du jambon de la carcasse. Enfin, ce modÚle de transfert a été couplé à un modÚle de microbiologie prédictive

    G-Quadruplex Visualization in Cells via Antibody and Fluorescence Probe

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    G-quadruplexes (G4s) are noncanonical nucleic acids structures involved in key regulatory and pathological roles in eukaryotes, prokaryotes, and viruses: the development of specific antibodies and fluorescent probes represent an invaluable tool to understand their biological relevance. We here present three protocols for the visualization of G4s in cells, both uninfected and HSV-1 infected, using a specific antibody and a fluorescent G4 ligand, and the effect of the fluorescent ligand on a G4 binding protein, nucleolin, upon binding of the molecule to the nucleic acids structure

    The nuclear receptors of Biomphalaria glabrata and Lottia gigantea: Implications for developing new model organisms

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    © 2015 Kaur et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are creditedNuclear receptors (NRs) are transcription regulators involved in an array of diverse physiological functions including key roles in endocrine and metabolic function. The aim of this study was to identify nuclear receptors in the fully sequenced genome of the gastropod snail, Biomphalaria glabrata, intermediate host for Schistosoma mansoni and compare these to known vertebrate NRs, with a view to assessing the snail's potential as a invertebrate model organism for endocrine function, both as a prospective new test organism and to elucidate the fundamental genetic and mechanistic causes of disease. For comparative purposes, the genome of a second gastropod, the owl limpet, Lottia gigantea was also investigated for nuclear receptors. Thirty-nine and thirty-three putative NRs were identified from the B. glabrata and L. gigantea genomes respectively, based on the presence of a conserved DNA-binding domain and/or ligand-binding domain. Nuclear receptor transcript expression was confirmed and sequences were subjected to a comparative phylogenetic analysis, which demonstrated that these molluscs have representatives of all the major NR subfamilies (1-6). Many of the identified NRs are conserved between vertebrates and invertebrates, however differences exist, most notably, the absence of receptors of Group 3C, which includes some of the vertebrate endocrine hormone targets. The mollusc genomes also contain NR homologues that are present in insects and nematodes but not in vertebrates, such as Group 1J (HR48/DAF12/HR96). The identification of many shared receptors between humans and molluscs indicates the potential for molluscs as model organisms; however the absence of several steroid hormone receptors indicates snail endocrine systems are fundamentally different.The National Centre for the Replacement, Refinement and Reduction of Animals in Research, Grant Ref:G0900802 to CSJ, LRN, SJ & EJR [www.nc3rs.org.uk]

    The Lee-Yang and P\'olya-Schur Programs. I. Linear Operators Preserving Stability

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    In 1952 Lee and Yang proposed the program of analyzing phase transitions in terms of zeros of partition functions. Linear operators preserving non-vanishing properties are essential in this program and various contexts in complex analysis, probability theory, combinatorics, and matrix theory. We characterize all linear operators on finite or infinite-dimensional spaces of multivariate polynomials preserving the property of being non-vanishing whenever the variables are in prescribed open circular domains. In particular, this solves the higher dimensional counterpart of a long-standing classification problem originating from classical works of Hermite, Laguerre, Hurwitz and P\'olya-Schur on univariate polynomials with such properties.Comment: Final version, to appear in Inventiones Mathematicae; 27 pages, no figures, LaTeX2

    Antioxidant activity relationship of phenolic compounds in Hypericum perforatum L.

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    <p>Abstract</p> <p>Background</p> <p>The St John's Wort (<it>Hypericum perforatum</it>; Clusiaceae) has been used in traditional and modern medicine for a long time due to its high content of biologically active phenolics. The purpose of this work was to develop a method for their fractionation and identification, and to determine the most active antioxidant compounds in plant extract.</p> <p>Results</p> <p>An LC-MS method which enables fast qualitative and semiquantitative analysis was developed. The composition determined is in agreement with the previous results, where 6 flavonoids, 4 naphthodianthrones and 4 phloroglucinols have been identified. Significant antioxidant activity was determined for most of the fractions by DPPH assay (the lowest IC<sub>50 </sub>of 0.52 ÎŒg/ml), NO scavenging (6.11 ÎŒg/ml), superoxide scavenging (1.86 ÎŒg/ml), lipid peroxidation (0.0079 ÎŒg/ml) and FRAP (the highest reduction capacity of 104 mg Fe equivalents/g) assays.</p> <p>Conclusion</p> <p>LC-MS technique has been successfully applied for a quick separation and identification of the major components of <it>H. perforatum </it>fractions. Majority of the fractions analyzed have expressed a very high antioxidative activity when compared to synthetic antioxidants. The antioxidant activity could be attributed to flavonoids and phenolic acids, while phloroglucinols and naphthodianthrones showed no significant activity. It is demonstrated that it is possible to obtain, by fractionation, <it>H. perforatum </it>preparations with significantly increased phloroglucinols-to-naphthodianthrones ratio (up to 95:5).</p

    Single-molecule visualization of DNA G-quadruplex formation in live cells.

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    Substantial evidence now exists to support that formation of DNA G-quadruplexes (G4s) is coupled to altered gene expression. However, approaches that allow us to probe G4s in living cells without perturbing their folding dynamics are required to understand their biological roles in greater detail. Herein, we report a G4-specific fluorescent probe (SiR-PyPDS) that enables single-molecule and real-time detection of individual G4 structures in living cells. Live-cell single-molecule fluorescence imaging of G4s was carried out under conditions that use low concentrations of SiR-PyPDS (20 nM) to provide informative measurements representative of the population of G4s in living cells, without globally perturbing G4 formation and dynamics. Single-molecule fluorescence imaging and time-dependent chemical trapping of unfolded G4s in living cells reveal that G4s fluctuate between folded and unfolded states. We also demonstrate that G4 formation in live cells is cell-cycle-dependent and disrupted by chemical inhibition of transcription and replication. Our observations provide robust evidence in support of dynamic G4 formation in living cells.Supported by programme grant funding from Cancer Research UK (C9681/A18618, S.B.) core funding from Cancer Research UK (C14303/A17197, S.B.), a Royal Society University Research Fellowship (UF120277 to S.F.L.), Research Professorship (RP150066 to D.K.), a EPSRC (EP/L027631/1 to D.K.) and a BBSRC David Phillips Fellowship (BB/R011605/1 to M.D.A
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