Showing papers by "Tokyo University of Science published in 1993"

Enhanced proliferative potential in culture of cells from p53-deficient mice

Abstract: Normal somatic cells are endowed with limited doubling potential in culture, and the process of immortalization is an inevitable step in neoplastic transformation of the cells. To examine the roles of p53 in this process, the cells of p53-deficient mice were examined for doubling potential. Fibroblast-like cells from a variety of tissues of these mice proliferated continuously without showing aging or crisis. The aneuploid cells overcome the population with passage, but cloning experiment indicated that chromosomal changes were not essential to this process. The enhanced proliferative potential in culture of cells from the p53-deficient mice was also observed in epithelial cells of lens, mammary glands and seminal vesicles and in neural precursor cells. Proliferation of bone marrow cells in response to stem cell factor was enhanced in long term culture, but not in in vitro colony assay; no permanent cell lines could be obtained. No effects of p53-deficiency were found in proliferation of cardiac muscle cells or hepatocytes.

Swelling of poly(N-isopropylacrylamide) gels in water-alcohol (C1-C4) mixed solvents

Abstract: The swelling volume of poly(N-isopropylacrylamide) gels in alcohol-water mixtures (C 1 -C 4 ) was measured at 25 o C. The swollen gel in water shrank first with addition of a small amount of alcohol and then reswelled on further addition of alcohol showing a typical reentrant transition. The swelling behavior of the gels was correlated with the properties of the aqueous alcohol mixtures (i.e., the change of alcohol molar volume and thermodynamic activities of alcohol and water). The uptake of ethanol and water in the equilibrated gels was measured at 25 o C. Ethanol was found to be selectively taken up in all aqueous alcohol mixtures

Molecular interactions between lipid and some steroids in a monolayer and a bilayer

Abstract: Molecular interactions between L-α-dipalmitoylphosphatidylcholine (DPPC) and some steroids having different hydrophilic groups in a monolayer and in a bilayer are investigated in terms of surface pressure, permeability, and microviscosity. The steroids used in this study are stigmasterol, 4,22-stigmastadien-3-one (stadiene), and stigmasterol acetate (acetate). The collapse pressures for the mixed monolayer of DPPC with various steroids depend upon the molar ratio (X) and types of hydrophilic groups in steroids. A one-stage collapse is observed for X ≤ 0.5 of stigmasterol, X ≤ 0.3 of stadiene and acetate, whereas a two-stage collapse is seen in other molar ratios of the steroids. The mole fraction within which liposomes are formed is dependent upon the types of hydrophilic group within the steroids. In comparing monolayer and bilayer membranes (liposomes), liposomes are formed at the mole fraction of steroids which have a one-stage collapse in DPPC/steroid mixed monolayer. The permeability ofthe bilayer membrane decreases with increasing cohesive force between DPPC and steroids, but increases with a decrease in microviscosity near the hydrophilic portions, in the following order : stigmasterol < stadiene < acetate. This study demonstrates that the permeability of liposomes is dependent upon the hydrophilic group of the steroids, and the stability of the liposomes increases with an increase in the cohesive forces between DPPC and the steroids.

From the managing editor

Abstract: This paper provides an overview of the area of resource discovery in the case of art images. Digitized art images are an important part of the online cultural heritage. Digitization and online accessibility were mainly materials focused on by libraries, museums, archives and audio-visual archives in the last decade. However, digitised art images as well as digitally-born art provide a major challenge for resource discovery and use. Better results in resource discovery could be achieved through methods combining queries executed on metadata with image retrieval methods. The paper gives an insight into the evolution of designated repositories for digital art, and then briefly presents some of the basic methods for intelligent resource discovery in this domain. Finally it looks at directions for further development within the digital repositories of art, which would enrich even more the user experiences. * Corresponding author.

The Resistivity Measurements of HgBa2Ca2Cu3O8+x and HgBa2Ca3Cu4O10+x Superconductors under High Pressure

Abstract: The superconductivity of the HgBa2Ca2Cu3O8+x (1223) and HgBa2Ca3Cu4O10+x (1234) phases was studied by resistivity measurements under high pressure The highest onset Tc (Tco) was 156 K at 25 GPa for a 1223 and 1234 mixed-phase sample and 140 K at 13 GPa for a 1223-phase sample The Tco decreased after the maximum point with the increase of pressure

Differential Affinity of Lymphocyte Subpopulations toward PHEMA Surface Derivatized with a Small Amount of Amino Groups—Evaluation under the Regulated Shear Stress

Abstract: The interaction of rat lymphocyte subpopulations with the surface of poly[N-methyl-N-(4-vinylphenethyl)ethylenediamine-co-2-hydroxyethyl methacrylate] (HAV copolymer) was evaluated under controlled shear stress by using a flat ribbon-like chamber with a plane-parallel type channel equipped with a polymer-coated bottom wall (hybrid field-flow fractionation/adsorption chromatography (FFF/AC) technique). Due to this simple geometry, it was able to control the hydrodynamic shear stress at the channel wall resulting from the parabolic flow in the channel. The cells in the channel were able to be detached from the polymer surface by increasing shear stress to exceed the strength of cell/materials interaction. Judging from the value of critical shear stress for lymphocyte take-off, the interaction force of lymph node lymphocytes was concluded to be minimized on the HAV copolymer containing 3 mol% of N-methyl-N-(4-vinylphenethyl)ethylenediamine (HAV3). This anomalous minimum of lymphocyte attachment by the introduction of a small amount of cationic sites on the surface is considered to be due to the drastic increase in free water content of polymers triggered by incorporated amino groups, which was demonstrated through DSC measurement. Further, by varying the settling time of lymphocytes in the chamber as well as by changing shear stress through the different profiles of applied flow, differential take-off of two major subpopulations of lymphocytes, B cells and T cells, was achieved on the HAV3 surface due to the differential contribution of the electrostatic interaction with HAV3 between B cells and T cells. This result indicated that the separation of B cells from T cells can be done by FFF/AC technique with a HAV3-coated chamber.

Metal-nonmetal transition in NiS induced by Fe and Co substitution: X-ray-absorption spectroscopic study.

Abstract: In order to reveal the microscopic origin of the metal-nonmetal transition in NiS, we have studied the Ni 2p x-ray-absorption spectra of substituted systems Ni 1-x M x S (M=Fe,Co), whose transition temperature T t varies from ∼500 K (Ni 05 Fe 05 S) to below 4 K (Ni 094 Co 006 S) Spectra taken at room temperature have been analyzed using a configuration-interaction cluster model to deduce changes in the electronic structure parameters, namely, the S-3p-to-Ni-3d charge-transfer energy Δ and the Ni-3d-S-3p transfer integral T We find that Fe substitution does not increase the local Ni-S distance as would be expected from the lattice parameters but affects energy levels as is reflected in Δ

Enantioselective synthesis of the α-hydroxy-α-methyl-β-hydroxy units via asymmetric aldol reaction

Abstract: The α-hydroxy-α-methyl-β-hydroxy units are enantioselectively prepared by way of asymmetric aldol reactions between both achiral β,β- disubstituted silyl enolates and aldehydes. (-)-2-C-Methyl-D-threono-1,4-lactone is conveniently synthesized by using this reaction

Determination of the crystal orientation of CuInSe2 by Raman spectroscopy

Abstract: We have developed a new method for the determination of the crystal orientation of CuInSe2 by Raman spectroscopy. The single crystal of CuInSe2 has a (112) natural surface. On this surface we often observe slip lines, which construct a triangular shape. However, it is difficult to identify which corner is the projection of the c axis. We established a new method to identify the c direction by using Raman spectroscopy. This method is also effective for small single crystals down to the size of 1 μm.

Determination of the CT gap of a Nd2CuO4-δ single crystal by high-temperature conductivity measurement

Abstract: The single crystal was grown by the TSFZ method, and the in-plane and c -axis conductivities were determined as functions of temperature and oxygen partial pressure. Arrhenius plots for in-plane and c -axis conductivity in the intrinsic region fall on straight lines. The in-plane mobility calculated by the combination of conductivity with oxygen nonstoichiometry was nearly independent of temperature and was regarded as 1.33 cm 2 V −1 s −1 . Assuming the temperature independence of the mobility, the CT gap was determined from the slope of the Arrhenius plot for conductivity. The CT gaps in the ab -plane and along the c -axis were found to be 1.21 and 1.22 eV, respectively. It was concluded that the same band contributes to conduction along the c -axis and in the ab -plane.

Effects of Gelatine and Cl- on a Copper Deposition

Abstract: The decomposition behavior of gelatine in the electrolyte and the effect of the decomposed species on Cu deposition have been investigated. The coeffect of gelatine and Cl- ion on Cu deposition was also studied. The results obtained are as follows.1. The morphology of the Cu deposits changed with the molecular weight and concentration of the gelatine. Gelatine decomposition behavior also changed with the molecular weight.2. The addition of gelatine increased the overpotential of the Cu deposition, while the addition of Cl- with the gelatine decreased the overpotential.3. It was found from the impedance analysis using an equivalent circuit that a two-step copper deposition reaction, Cu2+→Cu+→Cu, proceeds with a hydrogen evolution reaction.

Cryopreservation of transgenic mouse embryos by ultrarapid freezing

Abstract: Two transgenic mice lines were produced by introducing the rat GH antisense transgene and the chicken beta-actin promoter/firefly luciferase hybrid gene in our laboratory. We cryopreserved the transgenic embryos, obtained by fertilization in vitro with the sperm of hemizygous males for the transgene, by the ultrarapid freezing. The survival rates of cryopreserved 2-cell embryos were high (> 70%) at thawing in both lines and 53% and 16% of cryopreserved 2-cell embryos, respectively, developed to live young after transferring to oviducts of recipients. Each transgene was detected at about 40% of the live young from two transgenic lines. These results indicated that the cryopreservation of embryos by ultrarapid freezing was valuable for sustaining transgenic mouse lines without genetic contaminations.

Synthesis of Novel Types of Segmented Polyamineurea and Polyamine-Poly(ethylene oxide) Block Copolymer

Abstract: Synthesis of Novel Types of Segmented Polyamineurea and Polyamine-Poly(ethylene oxide) Block Copolymer

EXAFS Studies on (Cu, In)Se2

Abstract: The local structure of chalcopyrite (Cu, In)Se2 has been investigated by extended X-ray absorption fine structure (EXAFS) measurements on the Cu K- and the Se K-edges. The values of the Cu-Se and the In–Se bond lengths were determined for various values of the Cu/In ratio, and the Se position parameter u was estimated from the obtained bond lengths and the lattice parameters. For the sample with Cu/In=0.96, the u-values obtained from the Cu–Se and the In–Se bond lengths are consistent with each other, and it was determined as 0.223. On the other hand, the relation of these structural parameters show a deviation from the values expected for the chalcopyrite structure as the Cu/In ratio deviates from 0.96. These results indicate that the chalcopyrite single phase is obtained within a narrow range of the Cu/In ratio around 0.96 while a structural disorder due to either the compositional fluctuation or the multiphase occurs as the Cu/In ratio deviates from 0.96.

Buildings with Response Control Systems in Japan

Abstract: Today, there are more than 30 buildings with response control systems The system is defined as one that suppresses or controls the response to the vibrational motion input of the buildings, the structural elements, and the accommodations inside the buildings, by installing a certain system or device According to this definition, the response control system is a method which controls all kinds of vibration caused by wind, traffic and machinery loads, and so on This report presents the outline of the buildings with response control systems in Japan, and introduces the details of systems for earthquakes

Optical properties of znxcd1-xingas4 system

Abstract: We prepared ZnxCd1-xInGaS4 (x=0–1) crystals by normal freezing method and measured optical absorption, photoluminescence and X-ray diffraction. From the optical absorption, the optical energy gap and the emission peak energy of ZnxCd1-xInGaS4 system crystals were found to shift to higher photon energy with an increase of the composition x. From the photoluminescence spectra, the emission peak energy was found to shift to higher photon energy.

Destruction of Trace Organophosphorus Pesticides in Water by Ozonation with a Combination of Ultraviolet Irradiation

Abstract: 地表水又は地下水中の有機リン農薬を分解・除去する為のモデル実験として, ミニプラント実験装置 (12L) を使用してオゾン曝気, UV照射およびオゾン曝気/UV照射併用処理した場合の有機リン農薬 (初濃度, 4mg/L) の挙動を検討した。この実験では7種の有機リン農薬 (ベンスリド, ブタミホス, イソフェンホス, クロロピリホス, EPN, フェニトロチオンおよびトリクロルホン) を試験した。有機リン農薬水溶液をオゾン処理するとP=S型からChE阻害活性の高いP=O型へ速やかに変化したが, 酸化生成物の残留する傾向が認められた。UV照射のみによる処理では分子中のリン酸エステル結合の開裂反応が観察された。これに対し, オゾン/UV併用処理ではP=S型からP=O型への変換および続くリン酸エステル結合の開裂反応が速やかに進行することがわかった。反応はいずれも一次式に従い, オゾン (0.74, g/L/h) およびUV (48W) 併用処理したときの有機リン農薬 (pH7, 20℃) の半減期はいずれも20分以内であった。

Anharmonic Phonon Structure in the Tunneling Conductance of Bi-Cuprates

Abstract: Phonon structures in the tunneling conductance must be properly normalized to evaluate the intensity of the electron-phonon interaction. However, this is very difficult because of the absence of the exact normal-state conductivity. Therefore we propose another method to judge whether or not the intensity becomes stronger with a critical temperature Tc. This method compares the intensity of anharmonic structures, which are normalized to the single-phonon structures, between high- and low-Tc substances. Our data for Bi-cuprates strongly suggest that the electron-phonon interaction is stronger in higher-Tc substances.

Surface Modification Method of Magnetite Particles by use of Silane Coupling Agents Having Fluorocarbon Chain

Abstract: Surface modification method of fine magnetite particles by use of silane coupling agents having fluorocarbon chain was investigated. The magnetic fluid (1, 1, 2-trichloro-1, 2, 2trifluoroethane base) was prepared preliminarily by using oleic acid as a surfactant, and then allowed to react with the silane coupling agent. The amount of oleic acid removed from the magnetite surface during the reaction with the coupling agent was measured by the alkaline titration in methanol, and the high exchange rate (>99%) was observed. The modified fine magnetite particles with silane coupling agent could be well dispersed in poly (chlorotrifluoroethene) and produced the fluoro-oil based magnetic fluid.

Enantioselective Synthesis of the α‐Hydroxy‐α‐methyl‐β‐hydroxy Units via Asymmetric Aldol Reaction.

Abstract: The α-hydroxy-α-methyl-β-hydroxy units are enantioselectively prepared by way of asymmetric aldol reactions between both achiral β,β- disubstituted silyl enolates and aldehydes. (-)-2-C-Methyl-D-threono-1,4-lactone is conveniently synthesized by using this reaction