2,479 research outputs found

    Properties of planetary fluids at high pressure and temperature

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    In order to derive models of the interiors of Uranus, Neptune, Jupiter and Saturn, researchers studied equations of state and electrical conductivities of molecules at high dynamic pressures and temperatures. Results are given for shock temperature measurements of N2 and CH4. Temperature data allowed demonstration of shock induced cooling in the the transition region and the existence of crossing isotherms in P-V space

    Attitudes and Practice Patterns in the Use of OMM in Patients with Serious Illness

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    INTRODUCTION: In addition to evidence-based medicine, the osteopathic approach to person-centered care consists of the osteopathic philosophy of integrated structure and function and applying manual techniques to treat somatic dysfunction. Known collectively as Osteopathic Manipulative Medicine (OMM), this approach can be utilized when treating patients with both chronic and acute conditions; however, there is limited data on how often or to what extent OMM is used to treat pain and other symptoms in patients facing serious or life-limiting illnesses. METHODS: A voluntary, anonymous survey was created to capture the practice patterns and attitudes of osteopathic physicians, regardless of specialty, in the uses and benefits of OMM in treating patients with serious illness. The survey was approved by the IRB and designed using a Likert-scale, multiple choice format using Redcap software and permission to distribute the survey electronically was granted from various national and local professional organizations including the American Osteopathic Association (AOA), Pennsylvania Osteopathic Medical Association (POMA) and the PCOM alumni association. Among key data analyzed were the frequency of OMM use in serious or life-limiting illness (Cancer, CHF, and COPD), attitudes about OMM, beliefs about OMM, and use of OMM in older adults. RESULTS: Osteopathic Physicians that utilize OMM when treating patients with serious illness have found OMM to be beneficial when treating certain conditions such as chronic and musculoskeletal pain, shortness of breath, and nausea. The physicians who use OMM also felt comfortable and proficient when utilizing it to treat certain conditions. They also felt their foundation in osteopathic Medicine enabled them to approach and care for patients with empathy and compassion. DISCUSSION: OMM is used by many osteopathic physicians when treating pain and other symptoms of patients who have serious illness. OMM has been found to be beneficial when treating conditions related to CHF, COPD, and Cancer. Osteopathic Physicians who do utilize Osteopathic Manipulative Medicine believe that their training has allowed them to engage and treat patients with compassion and empathy

    Small-molecule Bcl-2 inhibitors sensitise tumour cells to immune-mediated destruction

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    The cytotoxic effects of anticancer immune cells are mediated by perforin/granzyme-B, Fas ligand and tumour necrosis factor-related apoptosis-inducing ligand (TRAIL), and therefore depend on intact apoptotic responses in target tumour cells. As killing by all three of these mechanisms is blocked by the frequently overexpressed antiapoptotic oncoprotein Bcl-2, we hypothesised that coexposure to a Bcl-2 inhibitor might enhance anticancer immune responses. We evaluated this in U937 lymphoma cells, and A02 melanoma cells, which both show strong Bcl-2 expression. Vα24+ Vβ11+ natural killer T (NKT) cells expanded from peripheral blood of normal donors (n=3) were coincubated with PKH26-labelled U937 cells, and cytotoxicity was determined by flow cytometry after annexin-V-FITC and 7-AAD staining. In all cases, addition of the HA14-1 small-molecule Bcl-2 inhibitor to the cocultures significantly increased apoptosis in the target U937 cells. Using a similar assay, killing of A02 cells by the cytotoxic T-lymphocyte clone 1H3 was shown to be amplified by coexposure to the potent small-molecule Bcl-2 inhibitor ABT-737. Experiments with immune effectors preincubated with concanamycin-A suggested that sensitisation to perforin/granzyme-B may underlie enhanced target-cell killing observed in the presence of Bcl-2 inhibitors. We conclude that immune destruction of malignant cells can be amplified by molecular interventions that overcome Bcl-2-mediated resistance to apoptosis

    High-pressure structural, elastic and electronic properties of the scintillator host material, KMgF_3

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    The high-pressure structural behaviour of the fluoroperovskite KMgF_3 is investigated by theory and experiment. Density functional calculations were performed within the local density approximation and the generalized gradient approximation for exchange and correlation effects, as implemented within the full-potential linear muffin-tin orbital method. In situ high-pressure powder x-ray diffraction experiments were performed up to a maximum pressure of 40 GPa using synchrotron radiation. We find that the cubic Pm\bar{3}m crystal symmetry persists throughout the pressure range studied. The calculated ground state properties -- the equilibrium lattice constant, bulk modulus and elastic constants -- are in good agreement with experimental results. By analyzing the ratio between the bulk and shear modulii, we conclude that KMgF_3 is brittle in nature. Under ambient conditions, KMgF_3 is found to be an indirect gap insulator with the gap increasing under pressure.Comment: 4 figure

    Anisotropic thermodynamics of d-wave superconductors in the vortex state

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    We show that the density of states and the thermodynamic properties of a 2D d-wave superconductor in the vortex state with applied magnetic field H\bf H in the plane depend on the angle between H\bf H and the order parameter nodes. Within a semiclassical treatment of the extended quasiparticle states, we obtain fourfold oscillations of the specific heat, measurement of which provides a simple probe of gap symmetry. The frequency dependence of the density of states and the temperature dependence of thermodynamic properties obey different power laws for field in the nodal and anti-nodal direction. The fourfold pattern is changed to twofold when orthorhombicity is considered.Comment: 5 pages, figures included, minor changes, published versio

    Self-organized Vortex State in Two-dimensional Dictyostelium Dynamics

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    We present results of experiments on the dynamics of Dictyostelium discoideum in a novel set-up which constraints cell motion to a plane. After aggregation, the amoebae collect into round ''pancake" structures in which the cells rotate around the center of the pancake. This vortex state persists for many hours and we have explicitly verified that the motion is not due to rotating waves of cAMP. To provide an alternative mechanism for the self-organization of the Dictyostelium cells, we have developed a new model of the dynamics of self-propelled deformable objects. In this model, we show that cohesive energy between the cells, together with a coupling between the self-generated propulsive force and the cell's configuration produces a self-organized vortex state. The angular velocity profiles of the experiment and of the model are qualitatively similar. The mechanism for self-organization reported here can possibly explain similar vortex states in other biological systems.Comment: submitted to PRL; revised version dated 3/8/9

    High Pressure Insulator-Metal Transition in Molecular Fluid Oxygen

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    We report the first experimental evidence for a metallic phase in fluid molecular oxygen. Our electrical conductivity measurements of fluid oxygen under dynamic quasi-isentropic compression show that a non-metal/metal transition occurs at 3.4 fold compression, 4500 K and 1.2 Mbar. We discuss the main features of the electrical conductivity dependence on density and temperature and give an interpretation of the nature of the electrical transport mechanisms in fluid oxygen at these extreme conditions.Comment: RevTeX, 4 figure

    Magnetic field dependence of superconducting energy gaps in YNi2B2C: Evidence of multiband superconductivity

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    We present results of in field directional point contact spectroscopy (DPCS) study in the quaternary borocarbide superconductor YNi2B2C, which is characterized by a highly anisotropic superconducting gap function. For I||a, the superconducting energy gap (D), decreases linearly with magnetic field and vanishes around 3.25T which is well below the upper critical field (Hc2~6T) measured at the same temperature (2.2K). For I||c, on the other hand, D decreases weakly with magnetic field but the broadening parameter (G) increases rapidly with magnetic field with the absence of any resolvable feature above 3.5T. From an analysis of the field variation of energy gaps and the zero bias density of states we show that the unconventional gap function observed in this material could originate from multiband superconductivity.Comment: 19 pages including figures (final version
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