2,191 research outputs found

    Measurement of the nuclear modification factor of electrons from heavy-flavour decays at mid-rapidity in Pb-Pb collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV with ALICE

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    We present results on inclusive electrons for 1.5 <pT< < p_{\rm T} < 6 GeV/cc in {Pb-Pb} collisions at sNN\sqrt{s_{\rm NN}} = 2.76 TeV measured with ALICE at the LHC and compare these to a cocktail of background electron sources. The excess of electrons beyond the cocktail at high momenta ({pT>p_{\rm T} > 3.5 GeV/cc}) is attributed to electrons from heavy-flavour decays. The corresponding nuclear modification factor indicates heavy-flavour suppression by a factor of 1.5-4.Comment: 4 pages; 4 figures; QM 2011 proceeding

    Nuclear collisions at the Future Circular Collider

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    The Future Circular Collider is a new proposed collider at CERN with centre-of-mass energies around 100 TeV in the pp mode. Ongoing studies aim at assessing its physics potential and technical feasibility. Here we focus on updates in physics opportunities accessible in pA and AA collisions not covered in previous Quark Matter contributions, including Quark-Gluon Plasma and gluon saturation studies, novel hard probes of QCD matter, and photon-induced collisions.Comment: 4 pages, 5 figures, proceedings of Quark Matter 201

    Long-Term Stability of TiS2–Alkylamine Hybrid Materials

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    Layered TiS2 intercalated with linear alkylamines has recently attracted significant interest as a model compound for flexible n-type thermoelectric applications, showing remarkably high power factors at room temperature. The thermal and, particularly, environmental stability of such materials is, however, a still an open challenge. In this paper, we show that amine-intercalated TiS2 prepared by a simple mechanochemical process is prone to chemical decomposition through sulfur exsolution, and that the presence of molecular oxygen is likely to mediate the decomposition reaction. Through computational analysis of the possible reaction pathways, we propose that Ti-N adducts are formed as a consequence of amine groups substituting for S vacancies on the internal surfaces of the S-Ti-S layers. These findings provide insights for possible future applications of similar hybrid compounds as devices operating in ambient conditions, and suggest isolating them from atmospheric oxygen

    Heavy-flavor dynamics in nucleus-nucleus collisions: from RHIC to LHC

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    The stochastic dynamics of c and b quarks in the fireball created in nucleus-nucleus collisions at RHIC and LHC is studied employing a relativistic Langevin equation, based on a picture of multiple uncorrelated random collisions with the medium. Heavy-quark transport coefficients are evaluated within a pQCD approach, with a proper HTL resummation of medium effects for soft scatterings. The Langevin equation is embedded in a multi-step setup developed to study heavy-flavor observables in pp and AA collisions, starting from a NLO pQCD calculation of initial heavy-quark yields, complemented in the nuclear case by shadowing corrections, k_T-broadening and nuclear geometry effects. Then, only for AA collisions, the Langevin equation is solved numerically in a background medium described by relativistic hydrodynamics. Finally, the propagated heavy quarks are made hadronize and decay into electrons. Results for the nuclear modification factor R_AA of heavy-flavor hadrons and electrons from their semi-leptonic decays are provided, both for RHIC and LHC beam energies.Comment: 4 pages, 2 figures (3 eps files); submitted for publication in the proceedings of "Quark Matter 2011", 23-28 May 2011, Annecy (France

    Mapping QGP properties in Pb--Pb and Xe--Xe collisions at the LHC

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    A phenomenological analysis of the experimental measurements of transverse momentum spectra of identified charged hadrons and strange hyperons in \PbPb and \XeXe collisions at the LHC is presented. The analysis is based on the relativistic fluid dynamics description implemented in the numerically efficient \fluidum approach. Building on our previous work, we separate in our treatment the chemical and kinetic freeze-out, and incorporate the partial chemical equilibrium to describe the late stages of the collision evolution. This analysis makes use of Bayesian inference to determine key parameters of the QGP evolution and its properties including the shear and bulk viscosity to entropy ratios, the initialisation time, the initial entropy density, and the freeze-out temperatures. The physics parameters and their posterior probabilities are extracted using a global search in multidimensional space with modern machine learning tools, such as ensembles of neural networks. We employ our newly developed fast framework to assess systematic uncertainties in the extracted model parameters by systematically varying key components of our analysis.Comment: 17 pages, 7 figure

    Swimming into peptidomimetic chemical space using pepMMsMIMIC

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    pepMMsMIMIC is a novel web-oriented peptidomimetic compound virtual screening tool based on a multi-conformers three-dimensional (3D)-similarity search strategy. Key to the development of pepMMsMIMIC has been the creation of a library of 17 million conformers calculated from 3.9 million commercially available chemicals collected in the MMsINC® database. Using as input the 3D structure of a peptide bound to a protein, pepMMsMIMIC suggests which chemical structures are able to mimic the protein–protein recognition of this natural peptide using both pharmacophore and shape similarity techniques. We hope that the accessibility of pepMMsMIMIC (freely available at http://mms.dsfarm.unipd.it/pepMMsMIMIC) will encourage medicinal chemists to de-peptidize protein–protein recognition processes of biological interest, thus increasing the potential of in silico peptidomimetic compound screening of known small molecules to expedite drug development

    Investigation of charm and beauty production via semileptonic decays of heavy-flavour hadrons in pp at 7 TeV and Pb--Pb at 2.76 TeV with ALICE

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    Electron spectra measured with ALICE at mid-rapidity are used to study the production of hadrons carrying a charm or a beauty quark. The production cross section of electrons from heavy-flavour hadron decays is measured in pp collisions at s\sqrt{s}=7 TeV. Electrons from the beauty decays are identified via the displacement from the interaction vertex. From the electron spectra measured in Pb--Pb collisions, we determine the nuclear modification factor, which is sensitive to the heavy-quark energy loss in a hot strongly interacting medium.Comment: Quark Matter 2011 proceeding

    Oral platelet gel supernatant plus supportive medical treatment versus supportive medical treatment in the management of radiation-induced oral mucositis: a matched explorative active control trial by propensity analysis

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    OBJECTIVES:: In this active control trial, the rate of radio-induced WHO grade 3/4 oral mucositis and the change in quality of life, assessed by OMWQ-HN, were measured in subjects with head and neck cancer treated by platelet gel supernatant (PGS) and supportive medical treatment versus subjects treated by supportive medical treatment alone. MATERIALS AND METHODS:: Eighty patients with nonmetastatic head and neck cancer underwent curative or adjuvant radiotherapy. All patients underwent supportive medical treatment and/or PGS at the beginning and during radiotherapy. Sixteen patients received PGS in association with supportive medical treatment. To obtain 2 groups virtually randomized for important clinical characteristics subjects were matched, by propensity analysis, with a group of subjects (64 patients) treated with supportive medical treatment alone. RESULTS:: Subjects treated with standard supportive treatment experienced significant higher WHO grade 3/4 toxicity (55%; 35/64) than subjects treated by PGS (13%; 3/16). The reduced toxicity found in PGS group paralleled with the evidence that they developed later symptoms with respect to controls. The Cox proportional hazard model indicated that patients treated with standard supportive medical treatment experienced 2.7-fold increase (hazard ratio=2.7; 95% confidence interval, 1.3-5.7) in the occurrence of WHO grade 3/4 toxicity. PGS group significantly experienced higher quality of life than control groups as measured by OMWQ-HN. A significant decrease in the opioid analgesics usage was found in the PGS group. CONCLUSIONS:: These preliminary data should be interpreted with caution and could serve as a framework around which to design future trials

    Neuroendocrine carcinomas of the breast

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    INTRODUCTION: Neuroendocrine (NE) breast cancers encompass a heterogeneous group of tumours showing morphological features similar to those of NE neoplasms of the gut and lung and expressing one or more neuroendocrine markers (neuron specific enolase, chromogranins synaptophysin) in at least 50% of tumour cells. They are rare lesions representing about 2-3% of all breast cancers and affecting more frequently elderly patients. AIM: Prospective observational study is to analyse the clinico-pathological aspects of NE carcinomas of the breast undergone surgical resection compared to breast carcinomas with a minor neuroendocrine component and to conventional invasive ductal or lobular cancers. MATERIAL AND METHOD: Thirty-five consecutive breast carcinomas showing morphological features suggestive of an endocrine differentiation were selected among breast cancers undergone surgical treatment during the period of January 1979-December 2004. RESULTS: The 35 patients were divided into two categories: 13 neuroendocrine carcinomas (NECs) and 22 ductal carcinomas with a minor neuroendocrine component (DC-NE). The average follow-up was 60 months. The patients with CNE developed breast cancer in an advanced age compared to the patients with infiltrating ductal carcinoma NAS or infiltrating lobular carcinoma. We did not find recurrent disease in the NEC group, while it was observed in 2 patients (9%) with DC-NE, in 6 cases (17%) with infiltrating ductal carcinoma NAS and in 7 cases (20%) with infiltrating lobular carcinoma. DISCUSSION: The CNE compared with the infiltrating ductal and lobular carcinoma are statistically different in relation to the expression of the receptor of c-erb-B2, p53, progesterone, for the lymph node state at diagnosis and the risk of reappearance of breast tumour. Our study confirms the choice to consider the neuroendocrine carcinoma of the breast as a separate histological group and seems to suggest a less aggressiveness of this type of tumou
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