121 research outputs found
New Melanogenesis and Photobiological Processes in Activation and Proliferation of Precursor Melanocytes after UV-Exposure: Ultrastructural Differentiation of Precursor Melanocytes from Langerhans Cells
Photobiological processes involving new melanogenesis after exposure to ultraviolet (UV) light were experimentally studied in C57 black adult mice by histochemistry, cytochemistry, and autoradiography. The trunk and the plantar region of the foot, where no functioning melanocytes were present before exposure, were exposed to UV-A for 14 consecutive days. Both regions revealed a basically similar pattern for new melanogenesis which involved an activation of precursor melanocytes. Essentially all of “indeterminate” cells appeared to be precursor melanocytes, the fine structure of which could be differentiated even from poorly developed Langerhans cells. New melanogenesis was manifested by 4 stages of cellular and subcellular reactions of these cells as indicated by histochemistry of dihydroxyphenylalanine (dopa) and autoradiography of thymidine incorporation: (a) an initial lag in the activation of precursor melanocytes with development of Golgi cisternae and rough endoplasmic reticulum followed by formation of unmelanized melanosomes (day 0 to 2); (b) synthesis of active tyrosinase accumulated in Golgi cisternae and vesicles with subsequent formation of melanized melanosomes in these cells (day 3 to 5); (c) mitotic proliferation of many of these activated cells, followed by an exponential increase of new melanocytes (day 6 to 7); and (d) melanosome transfer with differentiation of 10nm filaments and arborization of dendrites, but without any significant change in the melanocyte population (day 8 to 14). The melanosome transfer was, however, not obvious until after 7days of exposure. The size of newly synthesized melanosomes was similar to that of tail skin where native melanocytes were present before exposure
Development of an X-ray real-time stereo imaging technique using synchrotron radiation
An X-ray stereo imaging system with synchrotron radiation was developed to perform real-time stereo imaging and stereo angiography
Improvements on the method for determining of 210Pb and 210Po in lead
金沢大学理工研究域An improved method is proposed to determine the content of 210Pb in lead using 210Po measured by alpha-ray spectrometry. This improved method, which is based on radiochemical separation by DDTC-toluene extraction, employs EDTA and citrate as masking reagents for the lead ions. To selectively extract polonium from an alkaline solution, the pH dependency was examined using a liquid scintillation counting method. And pH 9 was chosen as an extraction condition. Then 210Po was electrodeposited on a stainless steel disk, and the chemical recovery was followed by 209Po tracer. The effectiveness of the new method was validated by the agreement with the analytical results from five samples as determined by gamma-ray spectrometry. © 2010 Akadémiai Kiadó, Budapest, Hungary
Space weathering structures on the surface micro-nano morphologies of Itokawa regolith particles.
第3回極域科学シンポジウム/第35回南極隕石シンポジウム 11月30日(金) 国立国語研究所 2階講
Inhomogeneous superconductivity in thin crystals of FeSe1-xTex (x=1.0, 0.95, and 0.9)
We investigated the temperature dependence of resistivity in thin crystals of FeSe1-xTex (x = 1.0, 0.95, and 0.9), though bulk crystals with 1.0 x 0.9 are known to be non-superconducting. With decreasing thickness of the crystals, the resistivity of x = 0.95 and 0.9 decreases and reaches zero at a low temperature, which indicates a clear superconducting transition. The anomaly of resistivity related to the structural and magnetic transitions completely disappears in 55- to 155-nm-thick crystals of x = 0.9, resulting in metallic behavior in the normal state. Microbeam x-ray diffraction measurements were performed on bulk single crystals and thin crystals of FeSe1-xTex. A significant difference of the lattice constant, c, was observed in FeSe1-xTex, which varied with differing Te content (x), and even in crystals with the same x, which was mainly caused by inhomogeneity of the Se/Te distribution. It has been found that the characteristic temperatures causing the structural and magnetic transition (T-t), the superconducting transition (T-c), and the zero resistivity (T-c(zero)) are closely related to the value of c in thin crystals of FeSe1-xTex
Prospective longitudinal comparative study of health-related quality of life in patients treated with radical prostatectomy or permanent brachytherapy for prostate cancer
To determine health-related quality of life (HRQOL) after radical retropubic prostatectomy (RRP) or permanent prostate brachytherapy (BT), third party-conducted QOL surveys were prospectively compared. Between 2004 and 2005, 37 patients underwent RRP and 36 were treated with BT. A QOL survey consisting of the Medical Outcomes Study 36-Item Short Form (SF-36), the University of California, Los Angeles, Prostate Cancer Index (UCLA-PCI) and the International Prostate Symptoms Score (IPSS) was completed prospectively by a research coordinator at baseline, and at 1, 3, 6 and 12 months after treatment. The RRP patients scored well in general QOL except at 1 month after surgery, with their mental health better than at baseline by 6 months after surgery. Disease-specific QOL in RRP patients received a low score at 1 month for both urinary and sexual function, though urinary function rapidly recovered to baseline levels. BT patient QOL was not affected by the therapy except in the IPSS score. However, general and mental health scores in BT patients were inferior to those in RRP patients. This prospective study revealed differences in QOL after RRP and BT. These results will be helpful in making treatment decisions.</p
Mineralogy and crystallography of some Itokawa particles returned by the Hayabusa asteroidal sample return mission
We studied seven Itokawa particles provided by the Japan Aerospace Exploration Agency (JAXA) as first International Announcement of Opportunity (AO) study mainly using electron and synchrotron radiation X-ray beam techniques. All the analyzed particles were collected from the first-touchdown site and composed of olivine and plagioclase with traces of Ca phosphate and chromite, and do not contain pyroxenes. Optical microscopy of these particles shows minor undulatory extinction of olivine and plagioclase, suggesting minor shock metamorphism (shock stage: S2). The electron microprobe analysis shows that olivine is Fo(70-73) and plagioclase is An(13-10)Or(5-7). The synchrotron radiation X-ray diffraction (SR-XRD) analysis of olivine crystals gives cell dimensions of a = 4.708 to 4.779 angstrom, b = 10.271 to 10.289 angstrom, c = 6.017 to 6.024 angstrom, corresponding to the Fo content of Fo(similar to 70) by Vegard's law. This composition matches the result obtained by the electron microprobe analysis. The olivine compositions of the analyzed particles are consistent with those of LL chondrites. The cell dimensions of two plagioclase crystals (a = 8.180 to 8.194 angstrom, b = 12.53 to 12.893 angstrom, c = 7.125 to 7.23 angstrom, a = 92.6 degrees to 93.00 degrees, beta = 116.36 degrees to 116.75 degrees, gamma = 90.03 degrees to 90.17 degrees) indicate that their equilibration temperatures are 800 degrees C +/- 10 degrees C. This temperature is near the peak metamorphic temperature recorded by equilibrated ordinary chondrites. The size of plagioclase crystals and the homogeneity of olivine compositions indicate that their petrologic type is >= 5. We also analyzed plagioclase by SR iron X-ray absorption near-edge structure (SR-XANES) and found that its Fe3+/(Fe2+ + Fe3+) ratio is approximately 0.5. Such high Fe3+ abundance indicates the formation under a relatively oxidizing environment. Thus, all these analyses have reconfirmed that the Itokawa particles returned by the Hayabusa spacecraft are very weakly shocked equilibrated LL chondrites, which matches the results of the preliminary examination team
D-braneworld cosmology
We discuss D-braneworld cosmology, that is, the brane is described by the
Born-Infeld action. Compared with the usual Randall-Sundrum braneworld
cosmology where the brane action is the Nambu-Goto one, we can see some drastic
changes at the very early universe: (i)universe may experience the rapid
accelerating phase (ii)the closed universe may avoid the initial singularity.
We also briefly address the dynamics of the cosmology in the open string
metric, which might be favorer than the induced metric from the view point of
the D-brane.Comment: 6 pages, 3 figures, minor corrections, accepted for publication in
Phys. Rev.
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