1,195 research outputs found

    Lambda polarization in pp -> p\Lambda K^+ \pi^+\pi^-\pi^+\pi^-

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    We show that there is a correlation between the invariant mass of the produced \Lambda K^+, \Lambda K^+\pi^+\pi^- or \Lambda K^+ \pi^+\pi^-\pi^+\pi^- system in the exclusive reaction pp\to p\Lambda K^+\pi^+\pi^-\pi^+\pi^- and the longitudinal or transverse momentum of Λ\Lambda. Together with the longitudinal and transverse momentum dependence of Lambda polarization observed in inclusive reactions, such a correlation implies a dependence of Lambda polarization on these invariant masses. The qualitative features of this dependence are consistent with the recent observation by E766 collaboration at BNL. A quantitative estimation has been made using an event generator for pppp collisions. A detailed comparison with the data is made.Comment: 10 pages with 3 figures, submitted to J. Phys.

    In-vivo pan/tilt endoscope with integrated light source

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    Endoscopic imaging is still dominated by the paradigm of pushing long sticks into small openings. This approach has a number of limitations for minimal access surgery, such as narrow angle imaging, limited workspace, counter-intuitive motions and additional incisions for the endoscpic instruments. Our intent is to go beyond this paradigm, and remotize sensors and effectors directly into the body cavity. To this end, we have developed a prototype of a novel insertable pan/tilt endoscopic camera with an integrated light source. The package has a size of 110 mm in length and 10 mm in diameter and can be inserted into the abdomen through a standard trocar and then anchored onto the abdominal wall, leaving the incision port open for access. The camera package contains three parts: an imaging module, an illumination module, and a pan/tilt motion platform. The imaging module includes a lens and CCD imaging sensor. The illumination module attaches to the imaging module and has an array of LED light sources. The pan/tilt platform provides the imaging module with pan of 120 degrees and tilt motion of 90 degrees using small servo motors. A fixing mechanism is designed to hold the device in the cavity. A standard joy stick can be used to control the motion of the camera in a natural way. The design allows for multiple camera packages to be inserted through a single incision as well

    Evaluation of warfarin resistance using transcription activator-like effector nucleases-mediated vitamin K epoxide reductase knockout HEK293 cells

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    Single nucleotide polymorphisms in the vitamin K epoxide reductase (VKOR) gene have been successfully used for warfarin dosage prediction. However, warfarin resistance studies of naturally occurring VKOR mutants do not correlate with their clinical phenotype. This discrepancy presumably arises because the in vitro VKOR activity assay is performed under artificial conditions using the non-physiological reductant dithiothreitol

    CD44 expression positively correlates with Foxp3 expression and suppressive function of CD4+ Treg cells

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    <p>Abstract</p> <p>Background</p> <p>CD4<sup>+</sup>CD25<sup>+ </sup>regulatory T (T<sub>reg</sub>) cells develop in the thymus and can suppress T cell proliferation, modulated by Foxp3 and cytokines; however, the relevance of CD44 in T<sub>reg </sub>cell development is less clear. To address this issue, we analyzed Foxp3 expression in CD44<sup>+ </sup>T<sub>reg </sub>cells by using multiple parameters, measured the levels of the immunoregulatory cytokine interleukin (IL)-10 in various thymocyte subsets, and determined the suppressor activity in different splenic T<sub>reg </sub>cell populations.</p> <p>Results</p> <p>Within mouse thymocytes, we detected T<sub>reg </sub>cells with two novel phenotypes, namely the CD4<sup>+</sup>CD8<sup>-</sup>CD25<sup>+</sup>CD44<sup>+ </sup>and CD4<sup>+</sup>CD8<sup>-</sup>CD25<sup>+</sup>CD44<sup>- </sup>staining features. Additional multi-parameter analyses at the single-cell and molecular levels suggested to us that CD44 expression positively correlated with Foxp3 expression in thymocytes, the production of IL-10, and T<sub>reg </sub>activity in splenic CD4<sup>+</sup>CD25<sup>+ </sup>T cells. This suppressive effect of T<sub>reg </sub>cells on T cell proliferation could be blocked by using anti-IL-10 neutralizing antibodies. In addition, CD4<sup>+</sup>CD25<sup>+</sup>CD44<sup>+ </sup>T<sub>reg </sub>cells expressed higher levels of IL-10 and were more potent in suppressing effector T cell proliferation than were CD4<sup>+</sup>CD25<sup>+</sup>CD44<sup>- </sup>cells.</p> <p>Conclusion</p> <p>This study indicates the presence of two novel phenotypes of T<sub>reg </sub>cells in the thymus, the functional relevance of CD44 in defining T<sub>reg </sub>cell subsets, and the role of both IL-10 and Foxp3 in modulating the function of T<sub>reg </sub>cells.</p> <p>Reviewers</p> <p>This article was reviewed by Dr. M. Lenardo, Dr. L. Klein & G. Wirnsberger (nominated by Dr. JC Zungia-Pfluker), and Dr. E.M. Shevach.</p

    Géomorphologie et productivité des forages dans le nord du bassin du fleuve Comoé en Côte d’Ivoire

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    L’objectif de cette étude est de caractériser les aquifères et la productivité des forages dans le haut bassin versant de la Comoé, spécifiquement dans la partie nord de la Côte d’Ivoire. La réalisation de ce travail a nécessité des fiches de 952 forages, des cartes géologiques et la base de données  cartographiques de la Côte d’Ivoire. Les épaisseurs d’altération y sont importantes avec 87,92% des forages supérieurs à la classe des épaisseurs moyennes selon le CIEH. Les forages y sont plus profonds et plus productifs sur les schistes que sur les granitoïdes. La profondeur optimale des forages dans cette zone peut être définie entre 40 et 60 m. Les valeurs de transmissivité varient de 5,59.10-6 m2/s à 2,01.10-4 m2/s.Mots clés : Fleuve Comoé, bassin versant, aquifère de socle, transmissivité, épaisseur d’altération, forage

    Effect of sulfate aerosol on tropospheric NOx and ozone budgets: Model simulations and TOPSE evidence

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    The distributions of NOx and O3 are analyzed during TOPSE (Tropospheric Ozone Production about the Spring Equinox). In this study these data are compared with the calculations of a global chemical/transport model (Model for OZone And Related chemical Tracers (MOZART)). Specifically, the effect that hydrolysis of N2O5 on sulfate aerosols has on tropospheric NOx and O3 budgets is studied. The results show that without this heterogeneous reaction, the model significantly overestimates NOx concentrations at high latitudes of the Northern Hemisphere (NH) in winter and spring in comparison to the observations during TOPSE; with this reaction, modeled NOx concentrations are close to the measured values. This comparison provides evidence that the hydrolysis of N2O5 on sulfate aerosol plays an important role in controlling the tropospheric NOx and O3 budgets. The calculated reduction of NOx attributed to this reaction is 80 to 90% in winter at high latitudes over North America. Because of the reduction of NOx, O3 concentrations are also decreased. The maximum O3reduction occurs in spring although the maximum NOx reduction occurs in winter when photochemical O3 production is relatively low. The uncertainties related to uptake coefficient and aerosol loading in the model is analyzed. The analysis indicates that the changes in NOxdue to these uncertainties are much smaller than the impact of hydrolysis of N2O5 on sulfate aerosol. The effect that hydrolysis of N2O5 on global NOx and O3 budgets are also assessed by the model. The results suggest that in the Northern Hemisphere, the average NOx budget decreases 50% due to this reaction in winter and 5% in summer. The average O3 budget is reduced by 8% in winter and 6% in summer. In the Southern Hemisphere (SH), the sulfate aerosol loading is significantly smaller than in the Northern Hemisphere. As a result, sulfate aerosol has little impact on NOx and O3 budgets of the Southern Hemisphere
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