140 research outputs found

    Comment on "On the subtleties of searching for dark matter with liquid xenon detectors"

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    In a recent manuscript (arXiv:1208.5046) Peter Sorensen claims that XENON100's upper limits on spin-independent WIMP-nucleon cross sections for WIMP masses below 10 GeV "may be understated by one order of magnitude or more". Having performed a similar, though more detailed analysis prior to the submission of our new result (arXiv:1207.5988), we do not confirm these findings. We point out the rationale for not considering the described effect in our final analysis and list several potential problems with his study.Comment: 3 pages, no figure

    Coating mechanisms of single-walled carbon nanotube by linear polyether surfactants: insights from computer simulations

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    The noncovalent coating of carbon-based nanomaterials, such as carbon nanotubes, has important applications in nanotechnology and nanomedicine. The molecular modeling of this process can clarify its mechanism and provide a tool for the design of novel materials. In this paper, the coating mechanism of single-walled carbon nanotubes (SWCNT) in aqueous solutions by 1,2-dimethoxyethane oxide (DME), 1,2-dimethoxypropane oxide (DMP), poly(ethylene oxide) (PEO), poly(propylene oxide) (PPO) pentamers, and L64 triblock copolymer chains have been studied using molecular dynamics (MD) simulations. The results suggest a preferential binding to the SWCNT surface of the DMP molecules with respect to DME mainly driven by their difference in hydrophobicity. For the longer pentamers, it depends by the chain conformation. PPO isomers with radius of gyration larger than PEO pentamers bind more tightly than those with more compact conformation. In the case of the L64 triblock copolymer, the coating of the SWCNT surface produces a shell of PPO blocks with the PEO chains protruding into bulk water as expected from the so-called nonwrapping binding mechanism of SWCNT. In addition, the polymer coating, in qualitative agreement with experimental evidence on the poor capability of the L64 to disperse SWCNT, do not prevent the formation of CNT aggregates

    Prognostic value of nuclear morphometry in patients with TNM stage T1 ovarian clear cell adenocarcinoma

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    In 40 patients with TNM stage T1 ovarian clear cell adenocarcinoma, we used nuclear morphometry to study the relations among morphometric variables, clinical prognostic factors and outcome. The presence of one or more giant nuclear cells was positively associated with death (OR = 10.6, P = 0.02) and tended to be associated with disease recurrence (OR = 5.1, P = 0.07). Nuclear irregularity (expressed in terms of the nuclear roundness factor) was positively associated with both death (OR = 8.6, P = 0.02) and disease recurrence (OR = 8.2, P = 0.02). A combination of giant nuclear cell presence or nuclear irregularity proved to be a useful prognostic indicator, with a sensitivity and specificity of 83% and 71% in the prediction of death, and 75% and 71% in the prediction of disease recurrence. Patients' age and substage were of no prognostic value. We conclude that the nuclear morphometric characteristics, especially the presence of giant nuclear cells and nuclear irregularity, may be useful in predicting outcome in patients with early stage ovarian clear cell adenocarcinoma. © 1999 Cancer Research Campaig

    Dark Matter Results from 225 Live Days of XENON100 Data

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    We report on a search for particle dark matter with the XENON100 experiment, operated at the Laboratori Nazionali del Gran Sasso (LNGS) for 13 months during 2011 and 2012. XENON100 features an ultra-low electromagnetic background of (5.3 \pm 0.6) \times 10^-3 events (kg day keVee)^-1 in the energy region of interest. A blind analysis of 224.6 live days \times 34 kg exposure has yielded no evidence for dark matter interactions. The two candidate events observed in the pre-defined nuclear recoil energy range of 6.6-30.5 keVnr are consistent with the background expectation of (1.0 \pm 0.2) events. A Profile Likelihood analysis using a 6.6-43.3 keVnr energy range sets the most stringent limit on the spin-independent elastic WIMP-nucleon scattering cross section for WIMP masses above 8 GeV/c^2, with a minimum of 2 \times 10^-45 cm^2 at 55 GeV/c^2 and 90% confidence level.Comment: 6 pages, 5 figures. Matches version accepted by PRL. Includes limits up to 10 TeV/c^2, published as supplementary material: http://prl.aps.org/supplemental/PRL/v109/i18/e181301 Please cite high mass limits as "Phys. Rev. Lett. 109, 181301 (2012), online supplementary material.

    Pseudoneoplastic lesions of the testis and paratesticular structures

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    Pseudotumors or tumor-like proliferations (non-neoplastic masses) and benign mimickers (non-neoplastic cellular proliferations) are rare in the testis and paratesticular structures. Clinically, these lesions (cysts, ectopic tissues, and vascular, inflammatory, or hyperplastic lesions) are of great interest for the reason that, because of the topography, they may be relevant as differential diagnoses. The purpose of this paper is to present an overview of the pseudoneoplasic entities arising in the testis and paratesticular structures; emphasis is placed on how the practicing pathologist may distinguish benign mimickers and pseudotumors from true neoplasia. These lesions can be classified as macroscopic or microscopic mimickers of neoplasia

    Synthesis of Cis

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