31,528 research outputs found

    Spin-current injection and detection in strongly correlated organic conductor

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    Spin-current injection into an organic semiconductor κ-(BEDT-TTF)2Cu[N(CN)2]Br\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br} film induced by the spin pumping from an yttrium iron garnet (YIG) film. When magnetization dynamics in the YIG film is excited by ferromagnetic or spin-wave resonance, a voltage signal was found to appear in the κ-(BEDT-TTF)2Cu[N(CN)2]Br\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br} film. Magnetic-field-angle dependence measurements indicate that the voltage signal is governed by the inverse spin Hall effect in κ-(BEDT-TTF)2Cu[N(CN)2]Br\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br}. We found that the voltage signal in the κ-(BEDT-TTF)2Cu[N(CN)2]Br\rm{\kappa\text{-}(BEDT\text{-}TTF)_2Cu[N(CN)_2]Br}/YIG system is critically suppressed around 80 K, around which magnetic and/or glass transitions occur, implying that the efficiency of the spin-current injection is suppressed by fluctuations which critically enhanced near the transitions

    Constructing entanglement witnesses for infinite-dimensional systems

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    It is shown that, every entangled state in an infinite-dimensional composite system has a simple entanglement witness of the form αI+T\alpha I+T with α\alpha a nonnegative number and TT a finite rank self-adjoint operator. We also provide two methods of constructing entanglement witness and apply them to obtain some entangled states that cannot be detected by the PPT criterion and the realignment criterion.Comment: 15 page

    A characterization of positive linear maps and criteria of entanglement for quantum states

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    Let HH and KK be (finite or infinite dimensional) complex Hilbert spaces. A characterization of positive completely bounded normal linear maps from B(H){\mathcal B}(H) into B(K){\mathcal B}(K) is given, which particularly gives a characterization of positive elementary operators including all positive linear maps between matrix algebras. This characterization is then applied give a representation of quantum channels (operations) between infinite-dimensional systems. A necessary and sufficient criterion of separability is give which shows that a state ρ\rho on HKH\otimes K is separable if and only if (ΦI)ρ0(\Phi\otimes I)\rho\geq 0 for all positive finite rank elementary operators Φ\Phi. Examples of NCP and indecomposable positive linear maps are given and are used to recognize some entangled states that cannot be recognized by the PPT criterion and the realignment criterion.Comment: 20 page

    CP asymmetries at D0

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    Using two independent measurements of the semileptonic CP asymmetry in the BsB_s system, we constrain the CP violating phase of the BsB_s system to be ϕs=0.700.39+0.47\phi_s = -0.70^{+0.47}_{-0.39}. The data sample corresponds to an integrated luminosity of 1.1 fb1^{-1} accumulated with D0 detector at the Fermilab Tevatron collider. We also measure the direct CP violating asymmetry in the decay B+J/ψK+B^+ \to J/\psi K^+ to be ACP(B+J/ψK+)=+0.0067±0.0074A_{CP}(B^+ \to J/\psi K^+) = +0.0067 \pm 0.0074(stat)±0.0026\pm0.0026(syst). The data corresponds to an integrated luminosity of 1.6 fb1^{-1}.Comment: contributed paper to EPS07, Manchester, UK, manuscript number EPSHEPP17

    Self-Diffusion in 2D Dusty Plasma Liquids: Numerical Simulation Results

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    We perform Brownian dynamics simulations for studying the self-diffusion in two-dimensional (2D) dusty plasma liquids, in terms of both mean-square displacement and velocity autocorrelation function (VAF). Super-diffusion of charged dust particles has been observed to be most significant at infinitely small damping rate γ\gamma for intermediate coupling strength, where the long-time asymptotic behavior of VAF is found to be the product of t1t^{-1} and exp(γt)\exp{(-\gamma t)}. The former represents the prediction of early theories in 2D simple liquids and the latter the VAF of a free Brownian particle. This leads to a smooth transition from super-diffusion to normal diffusion, and then to sub-diffusion with an increase of the damping rate. These results well explain the seemingly contradictory scattered in recent classical molecular dynamics simulations and experiments of dusty plasmas.Comment: 10 pages 5 figures, accepted by PR

    q-deformed Supersymmetric t-J Model with a Boundary

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    The q-deformed supersymmetric t-J model on a semi-infinite lattice is diagonalized by using the level-one vertex operators of the quantum affine superalgebra Uq[sl(21)^]U_q[\hat{sl(2|1)}]. We give the bosonization of the boundary states. We give an integral expression of the correlation functions of the boundary model, and derive the difference equations which they satisfy.Comment: LaTex file 18 page

    Molecular manipulation of keratin 8/18 intermediate filaments: modulators of FAS-mediated death signaling in human ovarian granulosa tumor cells

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    Background: Granulosa cell tumors (GCT) are a rare ovarian neoplasm but prognosis is poor following recurrence. Keratin intermediate filaments expressed in these tumors are a diagnostic marker, yet paradoxically, may also constitute a target for therapeutic intervention. In the current study, we evaluated keratin 8/18 (K8/18) filament expression as a mechanism of resistance to apoptosis in GCT, specifically focusing on regulation of the cell surface death receptor, Fas (FAS). Methods: The GCT cell line, KGN, was transiently transfected with siRNA to KRT8 and KRT18 to reduce K8/18 filament expression. Expression of K8/18, FAS, and apoptotic proteins (PARP, cleaved PARP) were evaluated by fluorescence microscopy, flow cytometric analysis, and immunoblotting, respectively. The incidence of FAS-mediated apoptosis in KGN cells was measured by caspase 3/7 activity. All experiments were performed independently three to six times, using a fresh aliquot of KGN cells for each experiment. Quantitative data were analyzed by one- or two-way analysis of variance (ANOVA), followed by a Tukey’s post-test for multiple comparisons; differences among means were considered statistically significant at P \u3c 0.05. Results: Control cultures of KGN cells exhibited abundant K8/18 filament expression (~90 % of cells), and minimal expression of FAS (\u3c25 % of cells). These cells were resistant to FAS-activating antibody (FasAb)-induced apoptosis, as determined by detection of cleaved PARP and measurement of caspase 3/7 activity. Conversely, siRNA-mediated knock-down of K8/18 filament expression enhanced FAS expression (\u3e 70 % of cells) and facilitated FasAb-induced apoptosis, evident by increased caspase 3/7 activity (P \u3c 0.05). Additional experiments revealed that inhibition of protein synthesis, but not MEK1/2 or PI3K signaling, also prompted FasAb-induced apoptosis. Conclusions: The results demonstrated that K8/18 filaments provide resistance to apoptosis in GCT by impairing FAS expression. The abundance of keratin filaments in these cells and their role in apoptotic resistance provides a greater mechanistic understanding of ovarian tumorgenicity, specifically GCT, as well as a clinically-relevant target for potential therapeutic intervention

    Antioxidant and Antitumor Activity of Indonesian Herbal Ingredients

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    The present study was to aimed to evaluated and compare in vitro antioxidant activities of 2 Indonesian herbal ingredients (A and B), determined total phenol content., cytotoxic and apoptosis induction activities on HL-60 cells. These data were providing some useful information for people healthy dietary and the new potential application of natural antioxidant containing food materials in functional foods and also as new cancer therapeutics promising candidates. The parameters were total antioxidant activity, amount of total cytotoxic effect on the growth of human promyelocytic leukemia cells (HL-60). Statistical comparison was perform with Student's t-test at p<0.05. The correlation coefficient (r2) between the parameters tested was established by regression analysis. The scavenging effect of extracts herbal on DPPH radicals increased from 0.3-1.5 mg/ml, where is sample A 14.33% to 64.29% and sample B 9.09% to 57.53% was obtained. High content of total phenol compounds were in sample A (21.72 mg GAE/g), lower amounts were in sample B (17.53 mg GAE/g). Apoptosis of HL-60 cells from the morphological changes side (chromatin condensation). Chromatin condensation, a specific and distinct feature of apoptotic cells, was found in the majority of treated cells. The results indicated that the cell death receptor pathway was involved in the apoptosis induced by Indonesian herbal extracts

    Ettingshausen effect due to Majorana modes

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    The presence of Majorana zero-energy modes at vortex cores in a topological superconductor implies that each vortex carries an extra entropy s0s_0, given by (kB/2)ln2(k_{B}/2)\ln 2, that is independent of temperature. By utilizing this special property of Majorana modes, the edges of a topological superconductor can be cooled (or heated) by the motion of the vortices across the edges. As vortices flow in the transverse direction with respect to an external imposed supercurrent, due to the Lorentz force, a thermoelectric effect analogous to the Ettingshausen effect is expected to occur between opposing edges. We propose an experiment to observe this thermoelectric effect, which could directly probe the intrinsic entropy of Majorana zero-energy modes.Comment: 16 pages, 3 figure
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