378 research outputs found

    Magnon scattering processes and low temperature resistivity in CMR manganites

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    Low temperature resistivity of CMR manganites is investigated. At the ground state, conduction electrons are perfectly spin polarized, which is called half-metallic. From one-magnon scattering processes, it is discussed that the resistivity of a half metal as a function of temperature scales as rho(T) - rho(0) propto T^3. We take (Nd,Tb,Sr)MnO_3 as an example to compare theory and experiments. The result is in a good agreement.Comment: To appear in Proc. ICM 200

    Guanidinium tetra­bromidomercurate(II)

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    The Hg atoms in the crystal structure of the title compound, (CH6N3)2[HgBr4], are tetra­hedrally coordinated by four Br atoms and the resulting [HgBr4]2− tetra­hedral ions are linked to the [C(NH2)3]+ ions by bromine–hydrogen bonds, forming a three-dimensional network. In the structure, the anions are located on special positions. The two different Hg⋯Br distances of 2.664 (1) and 2.559 (1) Å observed in the tetra­bromidomercurate unit are due to the connection of Br atoms to different number of H atoms

    Bis(guanidinium) tetra­iodidomercurate(II)

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    The Hg atom in the crystal structure of the title compound, (CH6N3)2[HgI4], is tetra­hedrally coordinated by four I atoms. The [HgI4]2− ions are inter­connected to the [C(NH2)3]+ ions by N—H⋯I hydrogen bonds, forming a three-dimensional network. The four different observed Hg—I distances [2.760 (2), 2.7762 (15), 2.8098 (14) and 2.833 (2) Å] are consistent with four different 127I NQR frequencies observed, showing the existence of four unique I atoms in the tetra­iodidomercurate unit

    Enveloped artificial viral capsids self-assembled from anionic beta-annulus peptide and cationic lipid bilayer

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    Anionic artificial viral capsids were self-assembled from β-annulus-EE peptide, then complexed with lipid-bilayer-containing cationic lipids via electrostatic interaction to form enveloped artificial viral capsids. The critical aggregation concentration of the enveloped artificial viral capsid was significantly lower than that of the uncomplexed artificial viral capsid, indicating that the lipid bilayer stabilised the capsid structure

    Impact-induced phyllosilicate formation from olivine and water

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    Shock-recovery experiments on mixtures of olivine and water with gas (air) were performed in a previous study to demonstrate water-mineral interactions during impact events (Furukawa et al., 2007). The products of these former experiments were investigated in the present study using transmission electron microscopy, scanning electron microscopy, and X-ray powder diffraction with the aim of finding evidence of aqueous alteration. Serpentine formed on the surface of shocked olivine with well-developed mosaicism. The yield of serpentine depended on the water/olivine ratio in the starting material, indicating progressive serpentinization under water-rich conditions. Comminution and mosaicism were developed in shocked olivine grains. The temperature and pressure changes of the samples during the experiments were estimated by constructing Hugoniots for mixtures of olivine and water, combined with the results of an additional fracturing experiment on a shocked container. Pressures and temperatures reached 4.6-7.2 GPa and at least 230-390 degrees C, respectively, for 0.7 mu s during in-shock compression. Post-shock temperatures reached a maximum of similar to 1300 degrees C, when the shock wave reached the gas in the sample cavity. The serpentine formed after the post-shock temperature maximum, most likely when temperatures dropped to between 200 and 400 degrees C. This is the first experiment to demonstrate the formation of phyllosilicates using heat supplied by an impact. The present results and estimations suggest that phyllosilicates could form as a result of impacts into oceans as well as by impacts on terrestrial and Martian crustal rocks, and on some asteroidal surfaces, where liquid or solid H(2)O is available. A significant amount of phyllosilicates would have formed during the late heavy bombardment of meteorites on the Hadean Earth, and such phyllosilicates might have affected the prebiotic carbon cycle. (C) 2011 Elsevier Ltd. All rights reserved

    Synchronous Quadruple Lung Cancer Treated Curatively by Photodynamic Therapy

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    A 54-year-old male was diagnosed as having synchronous quadruple early stage lung cancer. All four tumors showed the same histologic type of in-situ or microinvasive squamous cell carcinoma, but existed independently in different bronchi. Photodynamic therapy of these four lesions was successfully performed by fiberoptic bronchoscopy because of the patient's poor pulmonary function. The patient is alive and well 51 months later

    Adaptive Sampling Approach to the Negative Sign Problem in the Auxiliary Field Quantum Monte Carlo Method

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    We propose a new sampling method to calculate the ground state of interacting quantum systems. This method, which we call the adaptive sampling quantum monte carlo (ASQMC) method utilises information from the high temperature density matrix derived from the monte carlo steps. With the ASQMC method, the negative sign ratio is greatly reduced and it becomes zero in the limit Δτ\Delta \tau goes to zero even without imposing any constraint such like the constraint path (CP) condition. Comparisons with numerical results obtained by using other methods are made and we find the ASQMC method gives accurate results over wide regions of physical parameters values.Comment: 8 pages, 7 figure

    Spontaneous Pathological Complete Regression of Hepatocellular Carcinoma

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    Several possible mechanisms for spontaneous regression of hepatocellular carcinoma (HCC) have been reported. Spontaneous complete regression of HCC is extremely rare. We herein report a case of spontaneous pathological complete regression of HCC following decrement of elevated serum alpha-fetoprotein (AFP). The serum AFP of a 74-year-old man who underwent hepatic resection for HCC twice increased up to 7,529 ng/mL and then spontaneously decreased to 404 ng/mL in 2 months. Computed tomography, magnetic resonance imaging, and angiography revealed a liver tumor in segment 7 without early enhancement. With a diagnosis of recurrent HCC, partial hepatic resection was performed. The resected specimens revealed no HCC macroscopically, and pathological examination revealed only a small area with cell dysplasia. The patient remains well with normal serum AFP and protein induced by vitamin K absence or antagonist-II (PIVKA-II) levels for 29 months after the third hepatic resection without recurrence of HCC. We describe a case of spontaneous pathological complete regression of HCC following decrement of elevated serum AFP. Further studies are needed to identify the mechanism(s) of spontaneous regression of HCC
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