227 research outputs found

    Renormalization Group Approach to Einstein Equation in Cosmology

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    The renormalization group method has been adapted to the analysis of the long-time behavior of non-linear partial differential equation and has demonstrated its power in the study of critical phenomena of gravitational collapse. In the present work we apply the renormalization group to the Einstein equation in cosmology and carry out detailed analysis of renormalization group flow in the vicinity of the scale invariant fixed point in the spherically symmetric and inhomogeneous dust filled universe model.Comment: 16 pages including 2 eps figures, RevTe

    An unexplored role of the CrOx shell in an elaborated Rh/CrOx core–shell cocatalyst for photocatalytic water splitting: a selective electron transport pathway from semiconductors to core metals, boosting charge separation and H₂ evolution

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    A core–shell structured Rh/CrOx cocatalyst has endowed various semiconductors with high efficiency in water-splitting photocatalysis, where thin CrOx layers on Rh have been assumed to be physical blockers of O₂ to the metal surface to suppress unfavorable reverse reactions (e.g., catalytic H₂O formation from H₂ and O₂). Herein, we propose another unexplored but favorable function of CrOx layers: a selective electron transport pathway from photocatalysts to the Rh core boosting charge separation and H₂ production. The subsequent loading of CrOx layers onto Rh increased the rate of visible light H₂ evolution of a Bi₄NbO₈Cl photocatalyst, even in a half reaction with a hole scavenger where O₂ does not evolve. Transient absorption spectroscopy revealed that the CrOx layer increases the electron path from Bi₄NbO₈Cl to Rh. Importantly, the highest H₂-evolution activity was obtained by simultaneous photodeposition using CrIII and RhIII precursors, which had not yet been examined. In this sample, Rh nanoparticles were enclosed by an amorphous CrOx shell, where Rh particles were less directly attached to the semiconductor. Therein, CrOx inserted between Bi₄NbO₈Cl and Rh effectively suppresses undesirable hole transfer from Bi₄NbO₈Cl to Rh, while such hole transfer partially occurs when they are in direct contact. These results indicated that CrOx functions as a selective electron transport pathway and improves the H₂ evolution activity. Although the development strategy of cocatalysts has so far focused on surface redox reactions, this study offers a new approach for the design of highly efficient cocatalysts based on the carrier transfer process, especially at semiconductor–cocatalyst interfaces

    Microwave Spectroscopy of a Single Permalloy Chiral Metamolecule on a Coplanar Waveguide

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    We investigate the microwave spectroscopies of a micrometer-sized single permalloy (Py) chiral structure on coplanar waveguides (CPWs). Under an external dc magnetic field applied in a direction perpendicular to the microwave propagation, the Py chiral structure loaded on the center of the CPW signal line shows Kittel-mode ferromagnetic resonance. Contrastingly, the structure on the signal-line edge highlights two additional resonances: spin-wave resonance at a higher frequency, and unique resonance at a lower frequency of approximately 7.8 GHz. The resonance signal at 7.8 GHz originates from magnetically induced, geometry-driven resonance, although the resonance frequency does not depend on the external magnetic field. Moreover, the displacement of the Py structures on the signal line results in nonreciprocal microwave transmission, which is traced back to the edge-guide mode

    Changes in Knowledge Levels through Lectures on Radiotherapy to Nursing Students in Japan

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    Background:Recently, the number of patients choosing radiotherapy is increasing in Japan. It is necessary for even nurses to have knowledge of radiotherapy. We measured the degree of awareness with a lecture on how a nursing student can obtain knowledge of radiotherapy.Materials and methods: Forty nursing students who were in their third year and preparing for their national nursing certification in two months were recruited. The 90-min lecture covered a range of topics from general theories to specific concepts. The students were not informed that they would be required to fill a survey at the end of the lecture. This was to avoid bias that could occur from knowing in advance that a survey would be conducted.Results: The following items below were particularly remarkable. The distinction between the radiologist and the radiation oncologist. The radiotherapy is a local therapy. The pain from bone metastasis could be relieved.Conclusion: Students had very little knowledge on radiotherapy before the lecture. the results of this study indicated the need to increase the number of lectures on radiotherapy for nursing as well medical students. As the number of radiotherapy patients increases

    Inhomogeneity of Spatial Curvature for Inflation

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    We study how the initial inhomogeneities of the spatial curvature affect the onset of inflation in the closed universe. We consider a cosmological model which contains a radiation and a cosmological constant. In order to treat the inhomogeneities in the closed universe, we improve the long wavelength approximation such that the non-small spatial curvature is tractable in the lowest order. Using the improved scheme, we show how large inhomogeneities of the spatial curvature prevent the occurrence of inflation.Comment: 17 pages, revtex, 6 figures included using eps

    An Autopsy Case of Disseminated Cytomegalovirus Infection in a Classic Hemophiliac A with Acquired Immunodeficiency Syndrome

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    This is a case report of disseminated cytomegalovirus infection which occured in 23-year-old male hemophiliac with AIDS. He has been receiving Factor VIII concentrate. Postmortem examination revealed generalized CMV infection in the lungs, the adrenal glands and the large intestine resulting in multiple organ system failure. These observations suggest that when Factor VIII concentrate used, careful evaluation of the pathogens such as ATL and HIV is essential

    Onset of inflation in inhomogeneous cosmology

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    We study how the initial inhomogeneities of the universe affect the onset of inflation in the closed universe. We consider the model of a chaotic inflation which is driven by a massive scalar field. In order to construct an inhomogeneous universe model, we use the long wavelength approximation ( the gradient expansion method ). We show the condition of the inhomogeneities for the universe to enter the inflationary phase.Comment: 22 pages including 12 eps figures, RevTe

    Manipulation of charge carrier flow in Bi₄NbO₈Cl nanoplate photocatalyst with metal loading

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    Separation of photoexcited charge carriers in semiconductors is important for efficient solar energy conversion and yet the control strategies and underlying mechanisms are not fully established. Although layered compounds have been widely studied as photocatalysts, spatial separation between oxidation and reduction reaction sites is a challenging issue due to the parallel flow of photoexcited carriers along the layers. Here we demonstrate orthogonal carrier flow in layered Bi₄NbO₈Cl by depositing a Rh cocatalyst at the edges of nanoplates, resulting in spatial charge separation and significant enhancement of the photocatalytic activity. Combined experimental and theoretical studies revealed that lighter photogenerated electrons, due to a greater in-plane dispersion of the conduction band (vs. valence band), can travel along the plane and are readily trapped by the cocatalyst, whereas the remaining holes hop perpendicular to the plane because of the anisotropic crystal geometry. Our results propose manipulating carrier flow via cocatalyst deposition to achieve desirable carrier dynamics for photocatalytic reactions in layered compounds

    Effects of 3-styrylchromones on metabolic profiles and cell death in oral squamous cell carcinoma cells

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    Abstract4H-1-benzopyran-4-ones (chromones) are important naturally-distributing compounds. As compared with flavones, isoflavones and 2-styrylchromones, there are only few papers of 3-styrylchromones that have been published. We have previously reported that among fifteen 3-styrylchromone derivatives, three new synthetic compounds that have OCH3 group at the C-6 position of chromone ring, (E)-3-(4-hydroxystyryl)-6-methoxy-4H-chromen-4-one (compound 11), (E)-6-methoxy-3-(4-methoxystyryl)-4H-chromen-4-one (compound 4), (E)-6-methoxy-3-(3,4,5-trimethoxystyryl)-4H-chromen-4-one (compound 6) showed much higher cytotoxicities against four epithelial human oral squamous cell carcinoma (OSCC) lines than human normal oral mesenchymal cells. In order to further confirm the tumor specificities of these compounds, we compared their cytotoxicities against both human epithelial malignant and non-malignant cells, and then investigated their effects on fine cell structures and metabolic profiles and cell death in human OSCC cell line HSC-2. Cytotoxicities of compounds 4, 6, 11 were assayed with MTT method. Fine cell structures were observed under transmission electron microscope. Cellular metabolites were extracted with methanol and subjected to CE-TOFMS analysis. Compounds 4, 6, 11 showed much weaker cytotoxicity against human oral keratinocyte and primary human gingival epithelial cells, as compared with HSC-2, confirming their tumor-specificity, whereas doxorubicin and 5-FU were highly cytotoxic to these normal epithelial cells, giving unexpectedly lower tumor-specificity. The most cytotoxic compound 11, induced the mitochondrial vacuolization, autophagy suppression followed by apoptosis induction, and changes in the metabolites involved in amino acid and glycerophospholipid metabolisms. Chemical modification of lead compound 11 may be a potential choice for designing new type of anticancer drugs
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