1,603 research outputs found

    Effect of Diet on the Growth and Survival of Adrenalectomized Rats Treated with Corticosterone

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    Author Institution: Department of Anatomy, Medical College of Ohio at Toledo ; Bureau of Biological Research, Rutgers UniversityDietary protein content did not influence the life sustaining capacity of a daily 300 vg dose of corticosterone in adrenalectomized rats. A lower daily dosage of 150 ng was less effective when animals were fed a 5% casein diet. Depletion of body protein stores prior to adrenalectomy did not significantly alter the response pattern of animals maintained on a daily 300 fxg dose of corticosterone. Reducing the dietary protein content from 20% to 10% interfered with the capacity of the daily 150 /Jig dosage of corticosterone to support body weight gain in adrenalectomized rats. No significant changes in bod}^ weight were noted in adrenalectomized animals fed a 5% casein diet. Protein depletion had a favorable effect on this aspect of the hormone's activity when adrenalectomized rats were treated with the daily 300 ,ug dosage and refed 10% or 20% casein diets. Adrenalectomized animals maintained under these experimental conditions gained more weight than nondepleted animals fed the same diets

    GHz QKD at telecom wavelengths using up-conversion detectors

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    We have developed a hybrid single photon detection scheme for telecom wavelengths based on nonlinear sum-frequency generation and silicon single-photon avalanche diodes (SPADs). The SPAD devices employed have been designed to have very narrow temporal response, i.e. low jitter, which we can exploit for increasing the allowable bit rate for quantum key distribution. The wavelength conversion is obtained using periodically poled Lithium niobate waveguides (W/Gs). The inherently high efficiency of these W/Gs allows us to use a continuous wave laser to seed the nonlinear conversion so as to have a continuous detection scheme. We also present a 1.27GHz qubit repetition rate, one-way phase encoding, quantum key distribution experiment operating at telecom wavelengths that takes advantage of this detection scheme. The proof of principle experiment shows a system capable of MHz raw count rates with a QBER less than 2% and estimated secure key rates greater than 100 kbit/s over 25 km.Comment: 12 pages, 7 figure

    NMR Metabolomics for Stem Cell type discrimination

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    Cell metabolism is a key determinant factor for the pluripotency and fate commitment of Stem Cells (SCs) during development, ageing, pathological onset and progression. We derived and cultured selected subpopulations of rodent fetal, postnatal, adult Neural SCs (NSCs) and postnatal glial progenitors, Olfactory Ensheathing Cells (OECs), respectively from the subventricular zone (SVZ) and the olfactory bulb (OB). Cell lysates were analyzed by proton Nuclear Magnetic Resonance (1H-NMR) spectroscopy leading to metabolites identification and quantitation. Subsequent multivariate analysis of NMR data by Principal Component Analysis (PCA), and Partial Least Square Discriminant Analysis (PLS-DA) allowed data reduction and cluster analysis. This strategy ensures the definition of specific features in the metabolic content of phenotypically similar SCs sharing a common developmental origin. The metabolic fingerprints for selective metabolites or for the whole spectra demonstrated enhanced peculiarities among cell types. The key result of our work is a neat divergence between OECs and the remaining NSC cells. We also show that statistically significant differences for selective metabolites characterizes NSCs of different ages. Finally, the retrived metabolome in cell cultures correlates to the physiological SC features, thus allowing an integrated bioengineering approach for biologic fingerprints able to dissect the (neural) SC molecular specificitie

    Hacking commercial quantum cryptography systems by tailored bright illumination

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    The peculiar properties of quantum mechanics allow two remote parties to communicate a private, secret key, which is protected from eavesdropping by the laws of physics. So-called quantum key distribution (QKD) implementations always rely on detectors to measure the relevant quantum property of single photons. Here we demonstrate experimentally that the detectors in two commercially available QKD systems can be fully remote-controlled using specially tailored bright illumination. This makes it possible to tracelessly acquire the full secret key; we propose an eavesdropping apparatus built of off-the-shelf components. The loophole is likely to be present in most QKD systems using avalanche photodiodes to detect single photons. We believe that our findings are crucial for strengthening the security of practical QKD, by identifying and patching technological deficiencies.Comment: Revised version, rewritten for clarity. 5 pages, 5 figures. To download the Supplementary information (which is in open access), go to the journal web site at http://dx.doi.org/10.1038/nphoton.2010.21

    Content and Feedback Analysis of YouTube Videos: Football Clubs and Fans as Brand Communities

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    The use of Web 2.0 tools has been transforming the interaction between companies and their clients, especially for those that are selling emotional products. Consumers are generating and sharing contents concerning their favourite products on the web. Even if this process has been widely acknowledged, only a few studies have been specifically devoted to the analysis of both the contents and the feedback the consumers receive from other users. This article analyzes the online presence of sport brands through contents that are generated by sport clubs (official contents) and their fans (User Generated Content, UGC) on YouTube. After a description and classification of video contents, it examines the factors that influence the performance of the videos in terms of passive (videos views) and active behaviour (any kinds of interaction with videos) among the viewers. In order to carry out this analysis, 125 YouTube channels were considered thereby accounting for a total of 375 videos. Results show that official contents are those preferred by the users/consumers and that if the video displays a passive/purely informative content, the chance of getting an active behaviour from the users tends to decrease. These findings may help companies manage their online presence, creating awareness about contents and information that should be spread and shared on the web

    Development and test of 21 multiplex PCRs composed of SSRs spanning most of the apple genome

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    A series of 21 multiplex (MP) polymerase chain reactions containing simple sequence repeat (SSR) markers spanning most of the apple genome has been developed. Eighty-eight SSR markers, well distributed over all 17 linkage groups (LGs), have been selected. Eighty-four of them were included in 21 different MPs while four could not be included in any MPs. The 21 MPs were then used to genotype approximately 2,000 DNA samples from the European High-quality Disease-Resistant Apples for a Sustainable agriculture project. Two SSRs (CH01d03 and NZAL08) were discarded at an early stage as they did not produce stable amplifications in the MPs, while the scoring of the multilocus (ML) SSR Hi07d11 and CN44794 was too complex for large-scale genotyping. The testing of the remaining 80 SSRs over a large number of different genotypes allowed: (1) a better estimation of their level of polymorphism; as well as of (2) the size range of the alleles amplified; (3) the identification of additional unmapped loci of some ML SSRs; (4) the development of methods to assign alleles to the different loci of ML SSRs and (5) conditions at which an SSR previously described as ML would amplify alleles of a single locus to be determined. These data resulted in the selection of 75 SSRs out of the 80 that are well suited and recommended for large genotyping project

    Quantum Cryptography

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    Quantum cryptography could well be the first application of quantum mechanics at the individual quanta level. The very fast progress in both theory and experiments over the recent years are reviewed, with emphasis on open questions and technological issues.Comment: 55 pages, 32 figures; to appear in Reviews of Modern Physic

    Dispersionless limit of the noncommutative potential KP hierarchy and solutions of the pseudodual chiral model in 2+1 dimensions

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    The usual dispersionless limit of the KP hierarchy does not work in the case where the dependent variable has values in a noncommutative (e.g. matrix) algebra. Passing over to the potential KP hierarchy, there is a corresponding scaling limit in the noncommutative case, which turns out to be the hierarchy of a `pseudodual chiral model' in 2+1 dimensions (`pseudodual' to a hierarchy extending Ward's (modified) integrable chiral model). Applying the scaling procedure to a method generating exact solutions of a matrix (potential) KP hierarchy from solutions of a matrix linear heat hierarchy, leads to a corresponding method that generates exact solutions of the matrix dispersionless potential KP hierarchy, i.e. the pseudodual chiral model hierarchy. We use this result to construct classes of exact solutions of the su(m) pseudodual chiral model in 2+1 dimensions, including various multiple lump configurations.Comment: 37 pages, 10 figures, 2nd version: some extensions (Fig 3, Appendix A, additional references), 3rd version: some minor changes, additional reference
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