3,817 research outputs found

    Low-velocity anisotropic Dirac fermions on the side surface of topological insulators

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    We report anisotropic Dirac-cone surface bands on a side-surface geometry of the topological insulator Bi2_2Se3_3 revealed by first-principles density-functional calculations. We find that the electron velocity in the side-surface Dirac cone is anisotropically reduced from that in the (111)-surface Dirac cone, and the velocity is not in parallel with the wave vector {\bf k} except for {\bf k} in high-symmetry directions. The size of the electron spin depends on the direction of {\bf k} due to anisotropic variation of the noncollinearity of the electron state. Low-energy effective Hamiltonian is proposed for side-surface Dirac fermions, and its implications are presented including refractive transport phenomena occurring at the edges of tological insulators where different surfaces meet.Comment: 4 pages, 2 columns, 4 figure

    A method of measuring the amplitude-modulated vacuum field near a conducting mirror

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    Electromagnetic fields of the vacuum mode near a conducting mirror are modified with respect to those in free space, with their amplitudes having a sinusoidal spatial dependence from the mirror. Therefore if we combine this spatially amplitude-modulated vacuum field mode and intense coherent light with a beam splitter, we may detect this fluctuation of the vacuum mode in a homodyne detection scheme. It will give a new method to produce squeezed states of light with a single mirror placed close to an unused port of a beam splitter. We show that the amplitude fluctuation of the combined light can be reduced by a factor of 2 below that of the coherent light. We also discuss the limitations due to the finite line width of the laser and the effective absorption length of the photodiodes

    Transplantation of Adipose Derived Stromal Cells into the Developing Mouse Eye

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    Adipose derived stromal cells (ADSCs) were transplanted into a developing mouse eye to investigate the influence of a developing host micro environment on integration and differentiation. Green fluorescent protein-expressing ADSCs were transplanted by intraocular injections. The age of the mouse was in the range of 1 to 10 days postnatal (PN). Survival dates ranged from 7 to 28 post transplantation (DPT), at which time immunohistochemistry was performed. The transplanted ADSCs displayed some morphological differentiations in the host eye. Some cells expressed microtubule associated protein 2 (marker for mature neuron), or glial fibrillary acid protein (marker for glial cell). In addition, some cells integrated into the ganglion cell layer. The integration and differentiation of the transplanted ADSCs in the 5 and 10 PN 7 DPT were better than in the host eye the other age ranges. This study was aimed at demonstrating how the age of host micro environment would influence the differentiation and integration of the transplanted ADSCs. However, it was found that the integration and differentiation into the developing retina were very limited when compared with other stem cells, such as murine brain progenitor cell

    Effect of the prosthesis–patient mismatch on long-term clinical outcomes after isolated aortic valve replacement for aortic stenosis: A prospective observational study

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    BackgroundThe effect of prosthesis–patient mismatch (PPM) on clinical outcomes after aortic valve replacement remains controversial. We evaluated effect of PPM on long-term clinical outcomes after isolated aortic valve replacement in patients with predominant aortic stenosis.MethodsWe analyzed data from patients with predominant aortic stenosis who underwent isolated aortic valve replacement between January 1995 and July 2010. The indexed effective orifice area, obtained by dividing the in vivo effective orifice area by the patient’s body surface area, was used to define PPM as clinically nonsignificant (group I, 224 patients), mild (group II, 52 patients), moderate (group III, 39 patients), and severe (group IV, 36 patients).ResultsEarly survival was not significantly different among the groups, but overall survival was decreased gradually in group IV. Overall survival at 12 years was lower in group IV than in group I (92.8% ± 2.7% vs 67.0 ± 10.1, respectively; P = .001). Cardiac-related-death-free survival at 12 years was lower in patients with severe PPM. Left ventricular mass index decreased during the follow-up period in all groups. But left ventricular mass index was less decreased in group IV compared with groups I, II, and III. Age, severe PPM, and ejection fraction <40%, and New York Heart Association Functional Class IV were independent risk factors of overall survival on multivariate analysis. Severe PPM was an independent risk factor for cardiac-related death.ConclusionsSevere PPM showed an adverse effect on long-term survival, and was an independent risk factor for cardiac-related death. In addition, patients with severe PPM showed less decreasing left ventricular mass index during follow-up

    Impact of Toxocariasis in Patients with Unexplained Patchy Pulmonary Infiltrate in Korea

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    Toxocariasis is one of the causes of pulmonary eosinophilic infiltrate that is increasing in Korea. This study was designed to identify the prevalence of toxocara seropositivity in patients with unexplained pulmonary patchy infiltrate and to evaluate associated factors. We evaluated 102 patients with unexplained pulmonary patchy infiltrate on chest computed tomography (CT) scan. As a control set, 116 subjects with normal chest CT were also evaluated. History of allergic disease, drug use, parasitic disease and raw cow liver intake were taken. Blood eosinophil count and total IgE level were measured. Specific serum IgG antibody to Toxocara canis larval antigen and specific IgG antibodies to 4 other parasites were measured by enzyme-linked immunosorbent assay (ELISA). In the infiltrate group, 66.7% subjects were toxocara seropositive whereas 22.4% of the control group were seropositive (p<0.001). In the infiltrate group, patients with a history of eating raw cow liver (odds ratio [OR], 7.8) and patients with eosinophilia (OR, 5.2) had a higher incidence of toxocara seropositivity. Thirty-five percent of toxocara seropositive patients with infiltrate exhibited migrating infiltrate and 48% had decreased infiltrate on the follow-up CT. We recommend that toxocara ELISA should be performed in patients with unexplained pulmonary patchy infiltrate, and that the eating of raw cow liver should be actively discouraged

    Skin care benefits of bioactive compounds isolated from Zanthoxylum piperitum DC. (Rutaceae)

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    Purpose: To investigate skin care efficacies of Zanthoxylum pipetitum extract and isolated compounds. Methods: Ethanol extracts of leaves, branches and fruits of what were partitioned into n-hexane, chloroform, ethyl acetate, n-butanol and aqueous layers and some fractions were further analyzed to isolate five compounds. The isolated compounds were identified based on the proton and carbon nuclear magnetic resonance (NMR) spectra. Cosmetic efficacy tests of the extracts and isolated compounds were evaluated by in vitro tests. Results: Phytochemical studies of the chloroform and ethyl acetate layers led to the isolation of five compounds; quercitrin (1), afzelin (2), hydroxy-α-sanshool (3), α-sanshool (4) and hyperoside (5). In activity tests, the extracts showed inhibitory activity against inflammation response and melanin synthesis, and induction of procollagen type I C-peptide (PIP). Among the isolated compounds, hydroxy-α-sanshool (3) and α-sanshool (4) displayed significant anti-inflammatory activity. Conclusion: The results demonstrate that Z. piperitum extract and its active compounds possess a significant potential as a cosmeeutical agent for enhancing skin quality
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