105 research outputs found

    Neurochemical Changes in the Mouse Hippocampus Underlying the Antidepressant Effect of Genetic Deletion of P2X7 Receptors.

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    Recent investigations have revealed that the genetic deletion of P2X7 receptors (P2rx7) results in an antidepressant phenotype in mice. However, the link between the deficiency of P2rx7 and changes in behavior has not yet been explored. In the present study, we studied the effect of genetic deletion of P2rx7 on neurochemical changes in the hippocampus that might underlie the antidepressant phenotype. P2X7 receptor deficient mice (P2rx7-/-) displayed decreased immobility in the tail suspension test (TST) and an attenuated anhedonia response in the sucrose preference test (SPT) following bacterial endotoxin (LPS) challenge. The attenuated anhedonia was reproduced through systemic treatments with P2rx7 antagonists. The activation of P2rx7 resulted in the concentration-dependent release of [3H]glutamate in P2rx7+/+ but not P2rx7-/- mice, and the NR2B subunit mRNA and protein was upregulated in the hippocampus of P2rx7-/- mice. The brain-derived neurotrophic factor (BDNF) expression was higher in saline but not LPS-treated P2rx7-/- mice; the P2rx7 antagonist Brilliant blue G elevated and the P2rx7 agonist benzoylbenzoyl ATP (BzATP) reduced BDNF level. This effect was dependent on the activation of NMDA and non-NMDA receptors but not on Group I metabotropic glutamate receptors (mGluR1,5). An increased 5-bromo-2-deoxyuridine (BrdU) incorporation was also observed in the dentate gyrus derived from P2rx7-/- mice. Basal level of 5-HT was increased, whereas the 5HIAA/5-HT ratio was lower in the hippocampus of P2rx7-/- mice, which accompanied the increased uptake of [3H]5-HT and an elevated number of [3H]citalopram binding sites. The LPS-induced elevation of 5-HT level was absent in P2rx7-/- mice. In conclusion there are several potential mechanisms for the antidepressant phenotype of P2rx7-/- mice, such as the absence of P2rx7-mediated glutamate release, elevated basal BDNF production, enhanced neurogenesis and increased 5-HT bioavailability in the hippocampus

    Spin Textures of Exciton-Polaritons in a Tunable Microcavity with Large TE-TM Splitting.

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    We report an extended family of spin textures of zero-dimensional exciton-polaritons spatially confined in tunable open microcavity structures. The transverse-electric-transverse-magnetic (TE-TM) splitting, which is enhanced in the open cavity structures, leads to polariton eigenstates carrying quantized spin vortices. Depending on the strength and anisotropy of the cavity confining potential and of the TE-TM induced splitting, which can be tuned via the excitonic or photonic fractions, the exciton-polariton emissions exhibit either spin-vortex-like patterns or linear polarization, in good agreement with theoretical modeling

    Two-dimensional metal-chalcogenide films in tunable optical microcavities

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    Integration of quasi-two-dimensional (2D) films of metal-chalcogenides in optical microcavities permits new photonic applications of these materials. Here we present tunable microcavities with monolayer MoS2 or few monolayer GaSe films. We observe significant modification of spectral and temporal properties of photoluminescence (PL): PL is emitted in spectrally narrow and wavelength-tunable cavity modes with quality factors up to 7400; a 10-fold PL lifetime shortening is achieved, a consequence of Purcell enhancement of the spontaneous emission rate

    The police and the far right in Greece::a case study of police voting behaviour in Athens

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    The electoral advance of the far right party of Golden Dawn has left a clear mark on the Greek parliamentary elections of 2012. A less debated aspect of these results involves the extent of the electoral influence of Golden Dawn among police personnel. Using electoral data from two districts in Greece’s capital city, this paper explores the extent of that influence among major front line police units based in those localities. Our analysis obtains clear indications that Golden Dawn’s presence has been much more emphatic among police personnel than among the general public. These results warrant further exploration of this development, particularly in light of the possibility that far-right ideology may influence the character of everyday policing in Greece and the use of police discretion at the detriment of vulnerable or politically undesirable groups

    Supported by science?: what canadian naturopaths advertise to the public

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    <p>Abstract</p> <p>Background</p> <p>The increasing popularity of complementary and alternative medicines in Canada has led to regulatory reforms in Ontario and British Columbia. Yet the evidence for efficacy of these therapies is still a source of debate. Those who are supportive of naturopathic medicine often support the field by claiming that the naturopathic treatments are supported by science and scientific research.</p> <p>Methods</p> <p>To compare provinces that are regulated and unregulated, we examined the websites of 53 naturopathic clinics in Alberta and British Columbia to gain a sense of the degree to which the services advertised by naturopaths are science based.</p> <p>Results</p> <p>There were very few differences between the provinces in terms of the types of services offered and conditions treated. Many of the most common treatments--such as homeopathy, chelation and colon cleanses--are viewed by the scientific community to be of questionable value and have no scientific evidence of efficacy beyond placebo.</p> <p>Conclusions</p> <p>A review of the therapies advertised on the websites of clinics offering naturopathic treatments does not support the proposition that naturopathic medicine is a science and evidence-based practice.</p

    A Comparison of Wood Density between Classical Cremonese and Modern Violins

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    Classical violins created by Cremonese masters, such as Antonio Stradivari and Giuseppe Guarneri Del Gesu, have become the benchmark to which the sound of all violins are compared in terms of their abilities of expressiveness and projection. By general consensus, no luthier since that time has been able to replicate the sound quality of these classical instruments. The vibration and sound radiation characteristics of a violin are determined by an instrument's geometry and the material properties of the wood. New test methods allow the non-destructive examination of one of the key material properties, the wood density, at the growth ring level of detail. The densities of five classical and eight modern violins were compared, using computed tomography and specially developed image-processing software. No significant differences were found between the median densities of the modern and the antique violins, however the density difference between wood grains of early and late growth was significantly smaller in the classical Cremonese violins compared with modern violins, in both the top (Spruce) and back (Maple) plates (p = 0.028 and 0.008, respectively). The mean density differential (SE) of the top plates of the modern and classical violins was 274 (26.6) and 183 (11.7) gram/liter. For the back plates, the values were 128 (2.6) and 115 (2.0) gram/liter. These differences in density differentials may reflect similar changes in stiffness distributions, which could directly impact vibrational efficacy or indirectly modify sound radiation via altered damping characteristics. Either of these mechanisms may help explain the acoustical differences between the classical and modern violins

    I-TASSER server for protein 3D structure prediction

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    <p>Abstract</p> <p>Background</p> <p>Prediction of 3-dimensional protein structures from amino acid sequences represents one of the most important problems in computational structural biology. The community-wide Critical Assessment of Structure Prediction (CASP) experiments have been designed to obtain an objective assessment of the state-of-the-art of the field, where I-TASSER was ranked as the best method in the server section of the recent 7th CASP experiment. Our laboratory has since then received numerous requests about the public availability of the I-TASSER algorithm and the usage of the I-TASSER predictions.</p> <p>Results</p> <p>An on-line version of I-TASSER is developed at the KU Center for Bioinformatics which has generated protein structure predictions for thousands of modeling requests from more than 35 countries. A scoring function (C-score) based on the relative clustering structural density and the consensus significance score of multiple threading templates is introduced to estimate the accuracy of the I-TASSER predictions. A large-scale benchmark test demonstrates a strong correlation between the C-score and the TM-score (a structural similarity measurement with values in [0, 1]) of the first models with a correlation coefficient of 0.91. Using a C-score cutoff > -1.5 for the models of correct topology, both false positive and false negative rates are below 0.1. Combining C-score and protein length, the accuracy of the I-TASSER models can be predicted with an average error of 0.08 for TM-score and 2 Å for RMSD.</p> <p>Conclusion</p> <p>The I-TASSER server has been developed to generate automated full-length 3D protein structural predictions where the benchmarked scoring system helps users to obtain quantitative assessments of the I-TASSER models. The output of the I-TASSER server for each query includes up to five full-length models, the confidence score, the estimated TM-score and RMSD, and the standard deviation of the estimations. The I-TASSER server is freely available to the academic community at <url>http://zhang.bioinformatics.ku.edu/I-TASSER</url>.</p

    The pathology of familial breast cancer: Clinical and genetic counselling implications of breast cancer pathology

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    Approximately 5% of all breast cancers are due to one of the high-risk breast cancer genes BRCA1 and BRCA2, or possibly to a third or fourth moderate- to high-risk gene(s). A further proportion of cases arise in the presence of a less striking family history, with later average age at onset and lower penetrance: familial breast cancer. Bilaterality is a recognized feature of hereditary breast cancer. Cancers often present at an early age, with the contralateral risk high within 10 years. Proof that bilateral malignancies are separate primaries can be difficult histologically, however, especially within 3 years. The recent finding of specific pathological features related to BRCA1 and, to a lesser extent, BRCA2 mutations means that, in addition to bilaterality and family history, a pathological element can be entered into the risk calculation for the presence of BRCA1/BRCA2 mutations. This will facilitate the targeting of mutation testing to families in which a positive result is most likely, and may subsequently influence the clinical management of these families
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