129 research outputs found

    Protecting eyewitness evidence: Examining the efficacy of a self-administered interview tool

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    Given the crucial role of eyewitness evidence, statements should be obtained as soon as possible after an incident. This is not always achieved due to demands on police resources. Two studies trace the development of a new tool, the Self-Administered Interview (SAI), designed to elicit a comprehensive initial statement. In Study 1, SAI participants reported more correct details than participants who provided a free recall account, and performed at the same level as participants given a Cognitive Interview. In Study 2, participants viewed a simulated crime and half recorded their statement using the SAI. After a delay of 1 week, all participants completed a free recall test. SAI participants recalled more correct details in the delayed recall task than control participants

    Bacteria Modulate the CD8+ T Cell Epitope Repertoire of Host Cytosol-Exposed Proteins to Manipulate the Host Immune Response

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    The main adaptive immune response to bacteria is mediated by B cells and CD4+ T-cells. However, some bacterial proteins reach the cytosol of host cells and are exposed to the host CD8+ T-cells response. Both gram-negative and gram-positive bacteria can translocate proteins to the cytosol through type III and IV secretion and ESX-1 systems, respectively. The translocated proteins are often essential for the bacterium survival. Once injected, these proteins can be degraded and presented on MHC-I molecules to CD8+ T-cells. The CD8+ T-cells, in turn, can induce cell death and destroy the bacteria's habitat. In viruses, escape mutations arise to avoid this detection. The accumulation of escape mutations in bacteria has never been systematically studied. We show for the first time that such mutations are systematically present in most bacteria tested. We combine multiple bioinformatic algorithms to compute CD8+ T-cell epitope libraries of bacteria with secretion systems that translocate proteins to the host cytosol. In all bacteria tested, proteins not translocated to the cytosol show no escape mutations in their CD8+ T-cell epitopes. However, proteins translocated to the cytosol show clear escape mutations and have low epitope densities for most tested HLA alleles. The low epitope densities suggest that bacteria, like viruses, are evolutionarily selected to ensure their survival in the presence of CD8+ T-cells. In contrast with most other translocated proteins examined, Pseudomonas aeruginosa's ExoU, which ultimately induces host cell death, was found to have high epitope density. This finding suggests a novel mechanism for the manipulation of CD8+ T-cells by pathogens. The ExoU effector may have evolved to maintain high epitope density enabling it to efficiently induce CD8+ T-cell mediated cell death. These results were tested using multiple epitope prediction algorithms, and were found to be consistent for most proteins tested

    The Effect of Clustering on the Measurement of the Mobility of Potassium Ions in Nitrogen Gas

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    McDaniel and Martin (1971) have suggested that the zero-field reduced mobility of (unclustered) K+ ions in nitrogen at room temperature and low pressures (~ 0�1 torr) is accurately enough known to be useful in pressure calibration of drift tubes and other types of apparatus employed in atomic collision experiments, where the uncertainty in the value of the gas pressure frequently represents the largest source of error in the measurements. Elford (1971) has questioned the validity of this suggestion on the grounds that he has observed a very slight, explicit dependence of the reduced mobility of K+ ions on the gas pressure in drift tube experiments with nitrogen and other gases. Although this pressure effect cannot be reconciled with existing mobility theory (McDaniel and Mason 1972), Elford believes the effect to be real and hence maintains that in fact the true mobility of unclustered K+ ions in nitrogen is not accurately known. The purpose of this communication is to point out that Elford's experiments with nitrogen were conducted at pressures sufficiently high that significant clustering of nitrogen molecules with his K+ ions inevitably occurred and that consequently the suggestion of McDaniel and Martin (1971) is not weakened by his findings.</jats:p

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