2,142 research outputs found

    Resonant thermal transport in semiconductor barrier structures

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    I report that thermal single-barrier (TSB) and thermal double-barrier (TDB) structures (formed, for example, by inserting one or two regions of a few Ge monolayers in Si) provide both a suppression of the phonon transport as well as a resonant-thermal-transport effect. I show that high-frequency phonons can experience a traditional double-barrier resonant tunneling in the TDB structures while the formation of Fabry-Perot resonances (at lower frequencies) causes quantum oscillations in the temperature variation of both the TSB and TDB thermal conductances σTSB\sigma_{\text{TSB}} and σTDB\sigma_{\text{TDB}}.Comment: 4 pages. 4 figure.

    The Expression Patterns of ER, PR, HER2, CK5/6, EGFR, Ki-67 and AR by Immunohistochemical Analysis in Breast Cancer Cell Lines

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    The molecular classification for breast carcinomas has been used in clinical studies with a simple surrogate panel of immunohistochemistry (IHC) markers. The objective of this current project was to study the molecular classification of commonly used breast cancer cell lines by IHC analysis. Seventeen breast cancer cell lines were harvested, fixed in formalin and made into cell blocks. IHC analyses were performed on each cell block with antibodies to estrogen receptor (ER), progesterone receptor (PR), HER2, EGFR, CK5/6, Ki-67 and androgen receptor (AR). Among the 17 cell lines, MCF-7 and ZR-75-1 fell to Luminal A subtype; BT-474 to Luminal B subtype; SKBR-3, MDA-MD-435 and AU 565 to HER2 over-expression subtype; MDA-MB-231, MCF-12A, HBL 101, HS 598 T, MCF-10A, MCF-10F, BT-20, 468 and BT-483 to basal subtype. MDA-MB-453 belonged to Unclassified subtype. Since each subtype defined by this IHC-based molecular classification does show a distinct clinical outcome, attention should be paid when choosing a cell line for any study

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    Proton pump inhibitor and histamine-2 receptor antagonist use and risk of liver cancer in two population-based studies

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    The analysis of UK Biobank has been conducted using the UK Biobank Resource under Application Number 34374. We acknowledge collaboration with the Research Applications and Data Management Team lead by Ms Katie Wilde, University of Aberdeen in conducting this study. KTT is supported by the Vietnam International Education Cooperation Department. Access to PCCIU data was provided by Queen’s University Belfast and the Centre for Academic Primary Care, University of Aberdeen. Access to the UK Biobank was funded by a Cancer Research UK Population Research Postdoctoral Fellowship awarded to ÚCMcM. HGC is a co-investigator of the UKCRC Centre of Excellence for Public Health Northern Ireland.Peer reviewedPostprin

    Numerical study of the thermoelectric power factor in ultra-thin Si nanowires

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    Low dimensional structures have demonstrated improved thermoelectric (TE) performance because of a drastic reduction in their thermal conductivity, {\kappa}l. This has been observed for a variety of materials, even for traditionally poor thermoelectrics such as silicon. Other than the reduction in {\kappa}l, further improvements in the TE figure of merit ZT could potentially originate from the thermoelectric power factor. In this work, we couple the ballistic (Landauer) and diffusive linearized Boltzmann electron transport theory to the atomistic sp3d5s*-spin-orbit-coupled tight-binding (TB) electronic structure model. We calculate the room temperature electrical conductivity, Seebeck coefficient, and power factor of narrow 1D Si nanowires (NWs). We describe the numerical formulation of coupling TB to those transport formalisms, the approximations involved, and explain the differences in the conclusions obtained from each model. We investigate the effects of cross section size, transport orientation and confinement orientation, and the influence of the different scattering mechanisms. We show that such methodology can provide robust results for structures including thousands of atoms in the simulation domain and extending to length scales beyond 10nm, and point towards insightful design directions using the length scale and geometry as a design degree of freedom. We find that the effect of low dimensionality on the thermoelectric power factor of Si NWs can be observed at diameters below ~7nm, and that quantum confinement and different transport orientations offer the possibility for power factor optimization.Comment: 42 pages, 14 figures; Journal of Computational Electronics, 201

    Quasifree eta photoproduction from nuclei and medium modifications of resonances

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    We investigate the sensitivity of the differential cross section, recoil nucleon polarization and the photon asymmetry to changes in the elementary amplitude, medium modifications of the resonance (S11,D13)(S_{11},D_{13}) masses, as well as nuclear target effects. All calculations are performed within a relativistic plane wave impulse approximation formalism resulting in analytical expressions for all observables. The spin observables are shown to be unique tools to study subtle effects that are not accessible by only looking at the unpolarized differential cross section.Comment: 27 pages, 8 figures, Revtex, To be published in Phys. Rev.

    Imaging Shock Waves in Diamond with Both High Temporal and Spatial Resolution at an XFEL

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    The advent of hard x-ray free-electron lasers (XFELs) has opened up a variety of scientific opportunities in areas as diverse as atomic physics, plasma physics, nonlinear optics in the x-ray range and protein crystallography. In this article, we access a new field of science by measuring quantitatively the local bulk properties and dynamics of matter under extreme conditions, in this case by using the short XFEL pulse to image an elastic compression wave in diamond. The elastic wave was initiated by an intense optical laser pulse and was imaged at different delay times after the optical pump pulse using magnified x-ray phase-contrast imaging. The temporal evolution of the shock wave can be monitored, yielding detailed information on shock dynamics, such as the shock velocity, the shock front width and the local compression of the material. The method provides a quantitative perspective on the state of matter in extreme conditions

    A phase II study of chloroquinoxaline sulfonamide (CQS) in patients with metastatic colorectal carcinoma (MCRC)

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    Purpose: Phase II multicenter study investigated the efficacy and toxicity of the novel halogenated derivative of sulfaquixonaline Chloroquinoxaline Sulfonamide (CQS) in metastatic colorectal cancer. Experimental design: Eligible patients with metastatic or recurrent colorectal cancer received CQS at a dose schedule of 2000 mg/m 2 over an hour weekly for 4 weeks every 42 days. Treatment was continued until unexpected toxicity or disease progression. Results: A total of seventeen patients were enrolled on this study. 94% of all patients enrolled had prior treatment. Sixteen patients were evaluable for response with fifteen patients showing evidence of disease progression and one patient with prolonged stable disease. One patient had non-evaluable disease. Following this interim analysis, the drug was considered ineffective and the study was terminated early. The most frequent adverse event was anemia. No patients discontinued the treatment because of toxicity. Conclusion: CQS, when given at a dose of 2000 mg/m 2 weekly for 4 weeks every 42 days to patients with metastatic colorectal cancer, does not result in significant tumor regression.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/43416/1/10637_2005_Article_4827.pd
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