18,624 research outputs found

    Cross-Reactive Tumor Antigens in the Skin of Mice Exposed to Subcarcinogenic Doses of Ultraviolet Radiation

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    This study suggests that cross-reactive tumor-associated antigens (TAA) are induced in the epidermis mice exposed to subcarcinogenic doses of ultraviolet radiation (UVR). Foot-pad immunization of C3H mice with viable epidermal cells from syngeneic UVR-exposed mice induced cytotoxic cells in the draining lymph nodes (DLN). These cells were capable of lysing a battery of UVR-induced tumor targets in a short-term chromium release assay. In contrast, the DLN cells of mice immunized with epidermal cells from normal non-UVR-exposed mice did not mature into effector cells with antitumor activity. The spectrum of tumor recognition of cytotoxic cells induced by immunization with UVR-exposed epidermal cells was identical to that of cytotoxic T cells obtained from animals that were foot-pad immunized with UVR-induced tumor cells. Both cytotoxic cell populations were shown to lyse tumors of diverse origin, including syngeneic UVR- and methylcholanthrene-induced tumors, as well as allogeneic UVR-induced tumors. These cells displayed minimal lytic activity against YAC-1 lymphoma cells, peritoneal exudate cells, and concanavalin A-stimulated splenocytes. The results from this study demonstrate that antigens are expressed on UVR-exposed mouse epidermal cells prior to the emergence of skin tumors, and these antigens can induce cytotoxic cells with specificity for TAA. We conclude that the early antigenic changes observed in UVR-exposed epidermis and their effect on the host's immune system may influence the emergence and progression of UVR-induced skin cancers

    Random billiards with wall temperature and associated Markov chains

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    By a random billiard we mean a billiard system in which the standard specular reflection rule is replaced with a Markov transition probabilities operator P that, at each collision of the billiard particle with the boundary of the billiard domain, gives the probability distribution of the post-collision velocity for a given pre-collision velocity. A random billiard with microstructure (RBM) is a random billiard for which P is derived from a choice of geometric/mechanical structure on the boundary of the billiard domain. RBMs provide simple and explicit mechanical models of particle-surface interaction that can incorporate thermal effects and permit a detailed study of thermostatic action from the perspective of the standard theory of Markov chains on general state spaces. We focus on the operator P itself and how it relates to the mechanical/geometric features of the microstructure, such as mass ratios, curvatures, and potentials. The main results are as follows: (1) we characterize the stationary probabilities (equilibrium states) of P and show how standard equilibrium distributions studied in classical statistical mechanics, such as the Maxwell-Boltzmann distribution and the Knudsen cosine law, arise naturally as generalized invariant billiard measures; (2) we obtain some basic functional theoretic properties of P. Under very general conditions, we show that P is a self-adjoint operator of norm 1 on an appropriate Hilbert space. In a simple but illustrative example, we show that P is a compact (Hilbert-Schmidt) operator. This leads to the issue of relating the spectrum of eigenvalues of P to the features of the microstructure;(3) we explore the latter issue both analytically and numerically in a few representative examples;(4) we present a general algorithm for simulating these Markov chains based on a geometric description of the invariant volumes of classical statistical mechanics

    Control of threshold voltage in E-mode and D-mode GaN-on-Si metal-insulator-semiconductor heterostructure field effect transistors by in-situ fluorine doping of atomic layer deposition Al2O3 gate dielectrics

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    We report the modification and control of threshold voltage in enhancement and depletion mode AlGaN/GaN metal-insulator-semiconductor heterostructure field effect transistors through the use of in-situ fluorine doping of atomic layer deposition Al2O3. Uniform distribution of F ions throughout the oxide thickness are achievable, with a doping level of up to 5.5 × 1019 cm−3 as quantified by secondary ion mass spectrometry. This fluorine doping level reduces capacitive hysteretic effects when exploited in GaN metal-oxide-semiconductor capacitors. The fluorine doping and forming gas anneal also induces an average positive threshold voltage shift of between 0.75 and 1.36 V in both enhancement mode and depletion mode GaN-based transistors compared with the undoped gate oxide via a reduction of positive fixed charge in the gate oxide from +4.67 × 1012 cm−2 to −6.60 × 1012 cm−2. The application of this process in GaN based power transistors advances the realisation of normally off, high power, high speed devices

    Levonorgestrel-releasing intrauterine system vs. usual medical treatment for menorrhagia: An economic evaluation alongside a randomised controlled trial

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    Objective: To undertake an economic evaluation alongside the largest randomised controlled trial comparing Levonorgestrel-releasing intrauterine device ('LNG-IUS') and usual medical treatment for women with menorrhagia in primary care; and compare the cost-effectiveness findings using two alternative measures of quality of life. Methods: 571 women with menorrhagia from 63 UK centres were randomised between February 2005 and July 2009. Women were randomised to having a LNG-IUS fitted, or usual medical treatment, after discussing with their general practitioner their contraceptive needs or desire to avoid hormonal treatment. The treatment was specified prior to randomisation. For the economic evaluation we developed a state transition (Markov) model with a 24 month follow-up. The model structure was informed by the trial women's pathway and clinical experts. The economic evaluation adopted a UK National Health Service perspective and was based on an outcome of incremental cost per Quality Adjusted Life Year (QALY) estimated using both EQ-5D and SF-6D. Results: Using EQ-5D, LNG-IUS was the most cost-effective treatment for menorrhagia. LNG-IUS costs £100 more than usual medical treatment but generated 0.07 more QALYs. The incremental cost-effectiveness ratio for LNG-IUS compared to usual medical treatment was £1600 per additional QALY. Using SF-6D, usual medical treatment was the most cost-effective treatment. Usual medical treatment was both less costly (£100) and generated 0.002 more QALYs. Conclusion: Impact on quality of life is the primary indicator of treatment success in menorrhagia. However, the most costeffective treatment differs depending on the quality of life measure used to estimate the QALY. Under UK guidelines LNG-IUS would be the recommended treatment for menorrhagia. This study demonstrates that the appropriate valuation of outcomes in menorrhagia is crucial. Copyright: © 2014 Sanghera et al

    Improvements in High Speed, High Resolution Dynamic Digital Image Correlation for Experimental Evaluation of Composite Drive System Components

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    Composite materials have the potential to reduce the weight of rotating drive system components. However, these components are more complex to design and evaluate than static structural components in part because of limited ability to acquire deformation and failure initiation data during dynamic tests. Digital image correlation (DIC) methods have been developed to provide precise measurements of deformation and failure initiation for material test coupons and for structures under quasi-static loading. Attempts to use the same methods for rotating components (presented at the AHS International 68th Annual Forum in 2012) are limited by high speed camera resolution, image blur, and heating of the structure by high intensity lighting. Several improvements have been made to the system resulting in higher spatial resolution, decreased image noise, and elimination of heating effects. These improvements include the use of a high intensity synchronous microsecond pulsed LED lighting system, different lenses, and changes in camera configuration. With these improvements, deformation measurements can be made during rotating component tests with resolution comparable to that which can be achieved in static test

    A pragmatic randomised controlled trial of healing therapy in a gastroenterology outpatient setting

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    Introduction: To determine the benefits of healing therapy (spiritual healing) as an adjunct to conventional management in irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD). Methods: 200 outpatients with IBS or IBD were randomised to either conventional treatment (control) or conventional plus five sessions of healing therapy (intervention). After 12 weeks controls also had healing therapy. Outcomes used were, the Measure Yourself Medical Outcomes Profile (MYMOP). IBS-QOL, IBDQ, and symptom measures. Results: There was a significant improvement in the MYMOP score at week 6 (p < 0.001) which was maintained to week 12 (p < 0.001) and 24 (p < 0.001). Improvements in MYMOP were significantly greater in the intervention group at both 6 (p < 0.001) and 12 weeks (p < 0.001) with effect sizes of 0.7 (95% CI: 0.4–1.1) and 0.8 (95% CI: 0.4–1.2). Condition-specific data for IBS showed that most QoL dimensions had a significant minimum 10-point score improvement at 6 and 12 weeks. The overall score improvement was 12.9 units at week 6 (p < 0.001), 12.4 units at week 12 (p < 0.001) and 13.8 units at week 24 (p < 0.001). In IBD there was also similar score improvement, but only up to week 12 were there associations of improved social and bowel functions (p < 0.001, respectively). Between group differences were identified for QoL scores in IBS at both week 6 (p < 0.001) and 12 (p < 0.001) but only for week 12 (p < 0.001) in the IBD group. Conclusions: The addition of healing therapy to conventional treatment was associated with improvement in symptoms and QoL in IBS, and to a lesser extent in IBD

    Cold Bose gases with large scattering lengths

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    We calculate the energy and condensate fraction for a dense system of bosons interacting through an attractive short range interaction with positive s-wave scattering length aa. At high densities, n>>a−3n>>a^{-3}, the energy per particle, chemical potential, and square of the sound speed are independent of the scattering length and proportional to n2/3n^{2/3}, as in Fermi systems.Comment: 4 pages, 3 figure

    Molecular epidemiology of imported cases of leishmaniasis in Australia from 2008 to 2014

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    © 2015 Roberts et al. Leishmaniasis is a vector borne disease caused by protozoa of the genus Leishmania. Human leishmaniasis is not endemic in Australia though imported cases are regularly encountered. This study aimed to provide an update on the molecular epidemiology of imported leishmaniasis in Australia. Of a total of 206 biopsies and bone marrow specimens submitted to St Vincent's Hospital Sydney for leishmaniasis diagnosis by PCR, 55 were found to be positive for Leishmania DNA. All PCR products were subjected to restriction fragment length polymorphism analysis for identification of the causative species. Five Leishmania species/species complexes were identified with Leishmania tropica being the most common (30/55). Travel or prior residence in a Leishmania endemic region was the most common route of acquisition with ∼47% of patients having lived in or travelled to Afghanistan. Cutaneous leishmaniasis was the most common manifestation (94%) with only 3 cases of visceral leishmaniasis and no cases of mucocutaneous leishmaniasis encountered. This report indicates that imported leishmaniasis is becoming increasingly common in Australia due to an increase in global travel and immigration. As such, Australian clinicians must be made aware of this trend and consider leishmaniasis in patients with suspicious symptoms and a history of travel in endemic areas. This study also discusses the recent identification of a unique Leishmania species found in native kangaroos and a potential vector host which could create the opportunity for the establishment of a local transmission cycle within humans

    Theory Support for the Excited Baryon Program at the Jlab 12 GeV Upgrade

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    This document outlines major directions in theoretical support for the measurement of nucleon resonance transition form factors at the JLab 12 GeV upgrade with the CLAS12 detector. Using single and double meson production, prominent resonances in the mass range up to 2 GeV will be studied in the range of photon virtuality Q2Q^2 up to 12 GeV2^2 where quark degrees of freedom are expected to dominate. High level theoretical analysis of these data will open up opportunities to understand how the interactions of dressed quarks create the ground and excited nucleon states and how these interactions emerge from QCD. The paper reviews the current status and the prospects of QCD based model approaches that relate phenomenological information on transition form factors to the non-perturbative strong interaction mechanisms, that are responsible for resonance formation.Comment: 52 pages, 19 figures, White Paper of the Electromagnetic N-N* Transition Form Factor Workshop at Jefferson Lab, October 13-15, 2008, Newport News, VA, US

    Off Mass Shell Effects in Hadron Electric Dipole Moments

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    We note that off the quark mass shell the operators (pi+pf)μγ5(p_i+p_f)_\mu\gamma_5 and iσμν(pi−pf)νγ5i\sigma_{\mu\nu}(p_i -p_f)^\nu\gamma_5, both of which reduce to −σ⃗⋅E⃗-\vec{\sigma}\cdot\vec{E} in the non-relativistic limit, are no longer identical. In this paper we explore the effects of this difference in the contribution of these quark electric moments to hadronic electric moments.Comment: 21 pages, 1 figure, Revtex, uses psfi
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