22 research outputs found

    Search for Kaluza-Klein Graviton Emission in ppˉp\bar{p} Collisions at s=1.8\sqrt{s}=1.8 TeV using the Missing Energy Signature

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    We report on a search for direct Kaluza-Klein graviton production in a data sample of 84 pb1{pb}^{-1} of \ppb collisions at s\sqrt{s} = 1.8 TeV, recorded by the Collider Detector at Fermilab. We investigate the final state of large missing transverse energy and one or two high energy jets. We compare the data with the predictions from a 3+1+n3+1+n-dimensional Kaluza-Klein scenario in which gravity becomes strong at the TeV scale. At 95% confidence level (C.L.) for nn=2, 4, and 6 we exclude an effective Planck scale below 1.0, 0.77, and 0.71 TeV, respectively.Comment: Submitted to PRL, 7 pages 4 figures/Revision includes 5 figure

    Measurement of the average time-integrated mixing probability of b-flavored hadrons produced at the Tevatron

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    We have measured the number of like-sign (LS) and opposite-sign (OS) lepton pairs arising from double semileptonic decays of bb and bˉ\bar{b}-hadrons, pair-produced at the Fermilab Tevatron collider. The data samples were collected with the Collider Detector at Fermilab (CDF) during the 1992-1995 collider run by triggering on the existence of μμ\mu \mu and eμe \mu candidates in an event. The observed ratio of LS to OS dileptons leads to a measurement of the average time-integrated mixing probability of all produced bb-flavored hadrons which decay weakly, χˉ=0.152±0.007\bar{\chi} = 0.152 \pm 0.007 (stat.) ±0.011\pm 0.011 (syst.), that is significantly larger than the world average χˉ=0.118±0.005\bar{\chi} = 0.118 \pm 0.005.Comment: 47 pages, 10 figures, 15 tables Submitted to Phys. Rev.

    Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)1.

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    In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field

    Mechanisms of Disease: methyl-binding domain proteins as potential therapeutic targets in cancer

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    The methyl-CpG-binding domain (MBD) proteins 'read' and interpret the methylation moieties on DNA, and thus are critical mediators of many epigenetic processes. Currently, the MBD family comprises five members; MBD1, MBD2, MBD3, MBD4 and MeCP2. Although not a 'classical' MBD protein, Kaiso also mediates transcriptional repression by using zinc finger domains to bind its targets. Since DNA hypermethylation is a well-recognized mechanism underlying gene silencing events in both tumorigenesis and drug resistance, it is likely that the MBD proteins may be important modulators of tumorigenesis. We review the recent work addressing this possibility, and discuss several of the MBD proteins as potentially excellent novel therapeutic targets

    Kinase drug discovery 20 years after imatinib:progress and future directions

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    Design, fabrication, and modification of cost-effective nanostructured TiO2 for solar energy applications

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    One of the greatest challenges for human society and civilization is the development of powerful technologies to harness renewable solar energy to satisfy the ever-growing energy demands. Semiconductor nanomaterials have important applications in the field of solar energy conversion. Among these, TiO represents one of the most promising functional semiconductors and is extensively utilized in photoelectrochemical applications, including photocatalysis (e.g., H generation from water splitting) and photovoltaics (e.g., dye-sensitized solar cells, DSSCs). As such, many efforts have focused on developing and exploiting cost-effective nanostructured TiO materials for efficient solar energy applications

    Centrality dependence of identified particle elliptic flow in relativistic heavy ion collisions at sNN=\sqrt{s_{NN}}= 7.7-62.4 GeV

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    Elliptic flow (v2v_{2}) values for identified particles at midrapidity in Au + Au collisions measured by the STAR experiment in the Beam Energy Scan at the Relativistic Heavy Ion Collider at sNN=\sqrt{s_{NN}}= 7.7--62.4~GeV are presented for three centrality classes. The centrality dependence and the data at sNN=\sqrt{s_{NN}}= 14.5~GeV are new. Except at the lowest beam energies we observe a similar relative v2v_{2} baryon-meson splitting for all centrality classes which is in agreement within 15\% with the number-of-constituent quark scaling. The larger v2v_{2} for most particles relative to antiparticles, already observed for minimum bias collisions, shows a clear centrality dependence, with the largest difference for the most central collisions. Also, the results are compared with A Multiphase Transport model and fit with a Blast Wave model

    Centrality and Transverse Momentum Dependence of Elliptic Flow of Multistrange Hadrons and phi Meson in Au plus Au Collisions at root S NN=200 GeV

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    We present high precision measurements of elliptic flow near midrapidity (vertical bar y vertical bar < 1.0) for multistrange hadrons and phi meson as a function of centrality and transverse momentum in Au + Au collisions at center of mass energy root S (NN) = 200 GeV. We observe that the transverse momentum dependence of phi and Omega v(2) is similar to that of pi and p, respectively, which may indicate that the heavier strange quark flows as strongly as the lighter up and down quarks. This observation constitutes a clear piece of evidence for the development of partonic collectivity in heavy-ion collisions at the top RHIC energy. Number of constituent quark scaling is found to hold within statistical uncertainty for both 0%-30% and 30%-80% collision centrality. There is an indication of the breakdown of previously observed mass ordering between phi and proton v(2) at low transverse momentum in the 0%-30% centrality range, possibly indicating late hadronic interactions affecting the proton v(2)

    Beam-energy dependence of charge balance functions from Au plus Au collisions at energies available at the BNL Relativistic Heavy Ion Collider

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    Balance functions have been measured in terms of relative pseudorapidity (Delta(eta)) for charged particle pairs at the BNL Relativistic Heavy Ion Collider from Au + Au collisions at root s(NN) = 7.7 GeV to 200 GeV using the STAR detector. These results are compared with balance functions measured at the CERN Large Hadron Collider from Pb + Pb collisions at root s(NN) = 2.76 TeV by the ALICE Collaboration. The width of the balance function decreases as the collisions become more central and as the beam energy is increased. In contrast, the widths of the balance functions calculated using shuffled events show little dependence on centrality or beam energy and are larger than the observed widths. Balance function widths calculated using events generated by UrQMD are wider than the measured widths in central collisions and show little centrality dependence. The measured widths of the balance functions in central collisions are consistent with the delayed hadronization of a deconfined quark gluon plasma (QGP). The narrowing of the balance function in central collisions at root s(NN) = 7.7 GeV implies that a QGP is still being created at this relatively low energy
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