2,584 research outputs found

    Significant differences in incubation times in sheep infected with bovine spongiform encephalopathy result from variation at codon 141 in the PRNP gene

    Get PDF
    The susceptibility of sheep to prion infection is linked to variation in the PRNP gene, which encodes the prion protein. Common polymorphisms occur at codons 136, 154 and 171. Sheep which are homozygous for the A<sub>136</sub>R<sub>154</sub>Q<sub>171</sub> allele are the most susceptible to bovine spongiform encephalopathy (BSE). The effect of other polymorphisms on BSE susceptibility is unknown. We orally infected ARQ/ARQ Cheviot sheep with equal amounts of BSE brain homogenate and a range of incubation periods was observed. When we segregated sheep according to the amino acid (L or F) encoded at codon 141 of the PRNP gene, the shortest incubation period was observed in LL141 sheep, whilst incubation periods in FF<sub>141</sub> and LF<sub>141</sub> sheep were significantly longer. No statistically significant differences existed in the expression of total prion protein or the disease-associated isoform in BSE-infected sheep within each genotype subgroup. This suggested that the amino acid encoded at codon 141 probably affects incubation times through direct effects on protein misfolding rates

    Acerca del libro “Los duelos, huellas en el carácter y registro corporal”

    Get PDF
    En esta obra trato de realizar una investigación sobre temas referidos al carácter y los mecanismos defensivos del yo que se tramitan en  los  rasgos de  carácter. Para  ello  encaro   una visión estratificada del psiquismo, aludiendo a la importancia de los duelos, las  fijaciones tempranas y la combinación con patologías psicosomáticas que pudiesen devenir   de  aquello no incluido en lo psíquico por  déficit de elaboración

    Atomic density and temperature distributions in magneto-optical traps

    Get PDF
    A theoretical investigation into density, pressure, and temperature distributions in magneto-optical traps is presented. After a brief overview of the forces that arise from reradiation and absorption, a condition that the absorptive force be conservative is used to show that, if the temperature is uniform throughout the trap, any. density solutions to the force equations will not be physical. Further, consistent density solutions are unlikely to exist at all. In contrast, with a varying temperature reasonable solutions are demonstrated, with some restrictions. Doppler forces involved in ring-shaped trap structures are used to calculate orbit radii in racetrack geometry traps, and corrections to the present discrepancy between theoretical and experimental studies are discussed in the context of reradiation and diffusion

    A Comprehensive X-ray Absorption Model for Atomic Oxygen

    Get PDF
    An analytical formula is developed to represent accurately the photoabsorption cross section of O I for all energies of interest in X-ray spectral modeling. In the vicinity of the Kedge, a Rydberg series expression is used to fit R-matrix results, including important orbital relaxation effects, that accurately predict the absorption oscillator strengths below threshold and merge consistently and continuously to the above-threshold cross section. Further minor adjustments are made to the threshold energies in order to reliably align the atomic Rydberg resonances after consideration of both experimental and observed line positions. At energies far below or above the K-edge region, the formulation is based on both outer- and inner-shell direct photoionization, including significant shake-up and shake-off processes that result in photoionization-excitation and double photoionization contributions to the total cross section. The ultimate purpose for developing a definitive model for oxygen absorption is to resolve standing discrepancies between the astronomically observed and laboratory measured line positions, and between the inferred atomic and molecular oxygen abundances in the interstellar medium from XSTAR and SPEX spectral models

    Cost-effectiveness of testosterone treatment utilising individual patient data from randomised controlled trials in men with low testosterone levels

    Get PDF
    ACKNOWLEDGEMENTS Professor Graham Scotland (Health Services Research Unit and Health Economics Research Unit, University of Aberdeen, UK) for providing comments on an earlier draft of this article. The project was funded by the NIHR Health Technology Assessment Programme (project number: 17/68/01). The Section of Endocrinology and Investigative Medicine is funded by grants from the MRC and NIHR and is supported by the NIHR Biomedical Research Centre Funding Scheme and the NIHR/Imperial Clinical Research Facility. The views expressed are those of the author(s) and not necessarily those of the NHS, NIHR or Department of Health. Channa N. Jayasena was funded by NIHR post-doctoral fellowship and Waljit S. Dhillo by NIHR Senior Investigator Award.Peer reviewe
    corecore