Publications by authors named "Ataru Kobayashi"

The local field ion emission properties of helium and neon around a step edge atom of W(112) were examined at liquid nitrogen temperature using a micro-probe hole field ion microscope combined with a pulse-counting analysis. We have analyzed the mapped field ion densities obtained for both imaging gas atoms at their respective best local image voltages based on the formula for tunneling barrier strength and have evaluated the dipole moment of polarized adatom as well as the local field enhancement factor at the adatom site. We found that the dipole moments of helium and neon adatoms showed the same value, although the best local image field acting on the helium adatom is much higher than that on the neon adatom.

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Zinc(ii)-quinoxaline complexes, [Zn(hqxc)(2)(py)(2)] and [Zn(hqxc)(2)(DMSO)(2)] (hqxc = 3-hydroxy-2-quinoxalinecarboxylate, py = pyridine, DMSO = dimethyl sulfoxide), were prepared and characterized by X-ray crystallography and fluorescence spectroscopy. In both complexes, the zinc ion is six-coordinated by two equatorial bidentate hqxc ligands with an intramolecular hydrogen bond and two axial monodentate ligands such as pyridine or DMSO. In spite of similar coordination geometries, there is a remarkable difference between their solid-state fluorescent properties.

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Synthesis and characterization of resorcinol-acetone copolymer is described. The polymer was prepared by trifluoroacetic acid-catalyzed polymerization of resorcinol with acetone. According to the (1)H-NMR, (13)C-NMR, and MALDI-TOF Mass spectra data, the obtained polymer had three types of repeating units: isopropylidene bridged-resorcinol, chromane ring, and spiro-shaped double chromane ring, indicating that polymerization proceeded via simultaneous addition-condensation and cyclization of resorcinol with acetone.

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The performance of a narrow-linewidth nanosecond pulsed deep-UV coherent light source consisting of a frequency-tripled nanosecond pulsed Ti:sapphire laser injection seeded by a frequency-scanning cw Ti:sapphire laser has been characterized by using optogalvanic spectroscopy of silicon atoms as a diagnostic. The envelope of the optogalvanic spectrum indicates the pure Doppler broadening of silicon atoms, which was estimated to be as broad as 4 GHz, without the broadening effect from the laser linewidth itself.

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We have investigated the radiosensitizing effect of doranidazole, a hypoxic cells radiosensitizer, using SCCVII tumor cells of C3H mice and CFPAC-1 and MIA PaCa-2 human pancreatic tumor cells. The radiosensitivity of hypoxic SCCVII cells in vitro increased with 1 mM doranidazole by a factor of 1.34 and 1.

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We investigated the sensitizing effect of the 2-nitroimidazole analogue doranidazole, a new hypoxic radiosensitizer, on radiation-induced apoptosis in L5178Y cells. Apoptosis was assessed by checking DNA ladder formation, the presence of sub-G1 peaks in flow cytometry, and chromatin condensation. A radiosensitizing effect of doranidazole was also confirmed by a soft-agar colony assay of surviving cells.

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Today, no effective chemotherapy regimen has been established for non-resectable or postoperative recurrent gastric cancer, and most such therapy seems to be palliative. Thus, a highly effective chemotherapy that allows good patient QOL is desired. We report three gastric cancer patients responding to chronomodulation chemotherapy (tegafur + cisplatin + Isovorin) based on circadian rhythms plus a new antitumor drug, CPT-11.

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The effects of TGF-beta 1, beta 2 and beta 3 (TGF-beta) on levels of mRNA corresponding to the alpha chains of type XII and type XIV collagens in equine tenocyte cultures were assessed using the ribonuclease protection assay (RPA). The level of alpha1(XII) mRNA in untreated monolayer cultures was approximately 50- to 100-fold greater than alpha1(XIV) mRNA level. Addition of TGF-beta resulted in an increase in the amount of alpha1(XII) present and a decrease of alpha1(XIV) mRNA in a dose-dependent manner.

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In our institute, radical esophagectomy through mini-thoracolaparotomy has been performed as a less-invasive surgery for esophageal cancer since 1996. We describe the indications for and operative procedures of mini-thoracolaparotomy. Next we report the preliminary results of a prospective randomized trial that compared mini-thoracolaparotomy with conventional thoracolaparotomy in 30 patients without neoadjuvant therapy.

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