Showing papers by "University of Tsukuba published in 1986"

Effect of Cyclic Deformation on the Pseudoelasticity Characteristics of Ti-Ni Alloys

Abstract: Change in the pseudoelasticity characteristics of Ti-Ni alloys during tension cycling was investigated. The critical stress for inducing martensites and the hysteresis of a stress-strain curve decreased with increasing number of cyclic loading, while the permanent elongation increased. The degree of the change in these values showed a strong dependence on the maximum applied stress during stress-induced martensitic transformation. However, no change was induced by cyclic elastic deformation even though high stress was applied. It was also found that the stabilization of the pseudoelasticity characteristics during cyclic loading was established using special thermomechanical treatments which are effective to raise the critical stress for slip. Based on these results it is concluded that the cause for the effect of cyclic deformation is the generation of dislocations in the martensitic phase.

Deformation and transition behavior associated with theR-phase in Ti-Ni alloys

Abstract: Deformation behavior associated with theR-phase (rhombohedral phase) transition and the subsequent martensitic transformation was studied systematically in Ti-Ni alloys by tensile testing over a wide temperature range covering belowM f to aboveT′ R (>Af). Since the deformation and transition characteristics showed a strong dependence on thermo-mechanical treatment and Ni-content, internal structures were examined by electron microscopy in specimens with various Ni-content and thermo-mechanical treatment. As a result precipitates and/or dislocations were revealed in the specimens in which theR-phase transition occurs. Based on the above results, the effects of thermo-mechanical treatment and Ni-content on the deformation and transition characteristics were clarified for both theR-phase transition and the martensitic transformation.

Role of membrane transport in metabolism and function of glutathione in mammals.

Abstract: Glutathione I occurs in almost all living organisms, and its multifunctional properties have been attracting interest of many biochemists, physiologists, pharmacologists as well as clinical scientists. GSH 1 is a tripeptide with a structure of 7-L-glutamyl-Lcysteinylglycine, which is characterized by the yglutamyl peptide and the reactive thiol group. GSH is synthesized in two steps catalyzed by 7-glutamylcysteine synthetase [EC 6.3.2.2] (reaction 1) and glutathione synthetase [EC 6.3.2.3] (reaction 2), respectively.

Tilting modules of finite projective dimension

Abstract: Tilting modules are well known, and are useful in the representation theory of artinian algebras ([2-4, 6, 11]). The purpose of this paper is to define tilting modules of finite projective dimension and prove some fundamental results. A unital left A-module A T over a ring A is said to be a tilting module of projective dimension 0 is an integer) if it satisfies the following three conditions: (1) A T has a projective resolution

Cleft comodule algebras for a bialgebra

Abstract: (1986). Cleft comodule algebras for a bialgebra. Communications in Algebra: Vol. 14, No. 5, pp. 801-817.

Alkaloid production by hairy root cultures in Atropa belladonna

Abstract: Hairy roots were induced by inoculation of stems of sterile plants of Atropa belladonna with Agrobacterium rhizogenes. The axenic culture of the hairy roots isolated from the stems proliferated 60 fold as based on the initial fresh weight after one month of culture. The presence of atropine and scopolamine in hairy roots were examined by TLC and HPLC. Their amounts were analyzed by GLC. The results show that the amount of the two alkaloids in the axenic cultures was the same as or even higher than those of normal plants grown in the field.

Control of the developmental pathway of tobacco pollen in vitro

Abstract: We developed a new method for culture of isolated pollen. Using highly homogeneous populations of immature pollen grains of Nicotiana tabacum L. prepared by means of Percoll density gradient centrifugation, we could direct their developmental pathway by regulating certain culture conditions. When the pollen population was cultured in basal medium with glutamine, most pollen grains underwent normal maturation. On the other hand, when first cultured in basal medium without glutamine, most pollen grains did not mature but after transfer to medium with glutamine and sucrose began to divide. This method for inducing pollen cell division was possible only with midbinucleate pollen grains which are characterized by having no central vacuole and no or only a few starch grains. Evidently, some essential changes necessary for the embryogenic response can be induced by glutamine starvation only in pollen grains at a specific stage.

Crystal Structure, Composition and Morphology of a Precipitate in an Aged Ti-51 at%Ni Shape Memory Alloy

Abstract: Etude par microscopie electronique analytique a haute resolution et a haute tension. Le precipite est de structure rhomboedrique de parametre a=0,670 nm et α=113,8°. La composition determinee par spectrometrie dispersive de rayons X semble etre Ni 56 Ti 44

High-efficiency genetic transformation of maize by a mixture of pollen and exogenous DNA.

Abstract: High-efficiency genetic transformation was induced in a genetic stock of maize, Zea mays Linnaeus, by self-pollination of the recipient plants along with DNA of the donor. The highest frequency of transformed endosperm per ear was 9.29%. DNA was applied onto silks in a pollen/DNA pasty mixture. The exogenous DNA transferred into endosperm expressed itself in endosperm formation. It is not known, however, whether the exogenous DNA segment in endosperm had been incorporated or whether it was present in the nucleus additionally, fragmentally, or in some other state. It was revealed that all of four possible cases had occurred as follows: exogenous DNA was transferred into (i) both embryo and endosperm of the same kernel, (ii) embryo only, (iii) endosperm only, and (iv) neither embryo nor endosperm. It was also revealed that exogenous DNA that had entered into the embryo had been maintained through embryo formation, germination, vegetative growth and differentiation, and reproductive growth, and finally was manifested in embryo and/or endosperm of the following generation and acted in endosperm formation. The frequency of transformed endosperm in this generation, however, was rather low. It may be that exogenous DNA taken into the embryo was unstable.

Expression of a foreign gene in callus derived from DNA-treated protoplasts of rice (Oryza sativa L.)

Abstract: Protoplasts isolated from suspension cultures of rice cells were treated with bacterial plasmid DNA carrying a chimaeric gene consisting of the nopaline synthase promoter, the aminoglycoside phosphotransferase II (APH(3′)II) structural gene from bacterial transposon Tn5 and the terminator region from cauliflower mosaic virus DNA. Colonies capable of proliferating in medium containing kanamycin (100 μg/ml) were selected. A transformation frequency of approximately 2% to 3% was recorded in several experiments. The enzyme (APH(3′)II) was also detected in kanamycin-resistant callus, which had survived after repeated selection. There was some variation in the APH(3′)II activity in the transformants which paralleled the copy number of the inserted genes.

Coherent Kondo State in a Dense Kondo Substance: CexLa1-xCu6

Abstract: The electrical resistivity, magnetoresistance and magnetic susceptibility of single crystalline Ce x La 1- x Cu 6 ( x =0-1) have been measured down to mK region. As the Ce concentration is increased, the consecutive change from the dilute (incoherent) Kondo regime to the Kondo lattice (coherent) regime is observed. The characteristic features in the coherent Kondo regime are clearly observed in the resistivity and the magnetoresistance above x =0.7. The low temperature resistivity in Ce x La 1- x Cu 6 shows a T 2 dependence and the residual resistivity follows the Nordheim law. As for the coherence effect in CeCu 6 , the resistivity follows a T 2 dependence below 0.1 K, the magnetoresistance changes from negative to positive below about 0.15 K within applied magnetic fields and the susceptibility shows an enhanced Pauli paramagnetism below 1 K.

Ethanol production from starch by a coimmobilized mixed culture system of Aspergillus awamori and Zymomonas mobilis

Abstract: The production of ethanol from starch by a coimmobilized mixed culture system of aerobic and anaerobic microorganisms in Ca-alginate gel beads was investigated. The mold Aspergillus awamori was used as an aerobic amylolytic microorganism and an anaerobic bacterium, Zymomonas mobilis, as an ethanol producer. By controlling the mixing ratio of the microorganisms in the inoculum size, a desirable coimmobilized mixed culture system, in which the aerobic mycelia grew on and near the oxygen-rich surface of the gel beads while the anaerobic bacterial cells mainly grew in the oxygen-deficient central part of the gel beads, was naturally established under the aerobic culture conditions, and ethanol could be directly produced from starch by the system. The ethanol productivity by the system in flask culture was particularly affected by the shear stress (dependent on the shaking speed) which controlled the mycelial growth on the surface of the gel beads. Under optimum culture conditions in the flask culture, the glucose produced was instantly consumed, and was not observed in the culture broth; the final concentration of ethanol produced from 100 g/L starch was 25 g/L and the yield coefficient for ethanol, Y/sub p/s/, was 0.38. The ethanol productivity by the coimmobilized mixed culture systemmore » was compared with those by other various culture systems and the advantages of the system were clarified.« less

Regional distribution of amino acid transmitters in postmortem brains of presenile and senile dementia of Alzheimer type.

Abstract: We measured the concentrations of glutamate, aspartate, and gamma-aminobutyrate (GABA) in cortical and subcortical areas by an enzymatic fluorometric method in 9 patients with histologically verified Alzheimer's disease and senile dementia of the Alzheimer type (AD/SDAT), and in 10 age-matched normal control subjects. When compared with controls, the concentration of glutamate in cortical and subcortical areas of AD/SDAT brains was significantly reduced. The concentrations of aspartate and GABA were also reduced in several areas, but the magnitude of reduction was less than that of glutamate. This apparent reduction of glutamate in postmortem brains might have a bearing on pathophysiological mechanisms in AD/SDAT.

Light utilization efficiency and quantum yield of phytoplankton in a thermally stratified sea1

Abstract: Light utilization efficiency and quantum yield of phytoplankton in a thermally stratified temperate sea were evaluated. Underwater spectral irradiance was measured with a specially designed un- derwater irradiance meter and the specific absorption coefficient of phytoplankton was determined by a modified opal glass method. The light utilization efficiency of phytoplankton at each depth was derived from photosynthetically fixed energy divided by the energy penetrating into that depth, and quantum yield was estimated from photosynthetic rate divided by quanta absorbed by phy- toplankton. Vertical profiles of in situ photosynthetic rates per unit volume of water showed two peaks, the first at the depth of about 30% light level (ca. 45,000 cal m-2 h-l) and the second at the depth of about 1.5% light level (ca. 2,500 cal m-2 h-r) with about the same rates. The light utilization efficiency was about 0.5% at the first peak and 5% at the second, The quantum yield was about 0.02 mol C Einst-' at the surface peak and 0.1 at the subsurface peak. The latter value was nearly the same as the maximum yield reported from culture experiments.

Wave-vector- and magnetic-field-dependent spin fluctuations in the heavy-fermion system CeCu6.

Abstract: We have performed neutron-scattering measurements on a single crystal of ${\mathrm{CeCu}}_{6}$ in applied magnetic fields from 0 to 6.4 T. The observed momentum-dependent magnetic scattering implies the existence of short-range antiferromagnetic correlations. While it induces no resonances, the field broadens the spectra considerably at T=0.4 K. An effective Hamiltonian which incorporates both single-impurity Kondo properties and antiferromagnetic Ruderman-Kittel-Kasuya-Yosida interactions describes our data.

Species differences in lipid peroxide levels in lung tissue and investigation of their determining factors.

Abstract: Marked species differences in thiobarbituric acid reactant value (TBA value) in normal lung tissue of five species of animals were found. The order of the values was mouse greater than hamster greater than rat greater than guinea pig greater than rabbit, and the value for mice was 3.6 times higher than that for rabbit. The vitamin E (VE) and nonprotein sulfhydryls (NPSH) contents in lungs varied widely among the five animal species. Species differences were also observed on polyunsaturated fatty acid composition in lung phospholipids. The peroxidizability index (PI), which shows the relative rate of peroxidation reaction, was calculated from the composition ratio and the reactivity of each polyunsaturated fatty acid, and the PI was found to be significantly correlated to the TBA value in lungs (r = 0.853, p less than 0.001). The PI value was normalized by the contents of VE and/or NPSH. Finally, the log-value of PI, normalized by the log values of the reciprocals of VE and NPSH, log(PI/VE X NPSH), showed the highest correlation coefficient (r = 0.907, p less than 0.001). Normalization by the activities of antioxidative protective enzymes in lungs did not show any significant correlation against TBA value. These results suggest that TBA value as an index of lipid peroxides in the lungs of animals may be regulated mainly by the contents of VE and NPSH, the composition ratio and the reactivity of each polyunsaturated fatty acid in lung phospholipid fraction.

Auxin-Controlled Glycoprotein Release into the Medium of Embryogenic Carrot Cells

Abstract: Glycoproteins released from carrot cells into culture media were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and visualized by staining with Coomassie brilliant blue or with the periodic-acid Schiff procedure The appearance or disappearance of two glycoproteins of Mr 65,000 (GP65) and Mr 57,000 (GP57) was closely related to the formation of somatic embroys GP65 was released specifically from embryogenic cells cultured in a medium without 2,4-dichlorophenoxyacetic acid, in which they can form somatic embryos GP57 was released from the same embryogenic cells, if they were cultured in a medium with 2,4-dichlorophenoxyacetic acid, in which they cannot form somatic embryos Nonembryogenic cells which cannot form somatic embryos, released only GP57

Automobile Prices and Quality: Did the Gasoline Price Increases Change Consumer Tastes in the U.S.?

Abstract: A hedonic model of automobile prices that takes gasoline costs into account is developed and used to examine whether gasoline price increases (especially those related to the 1973 and 1979 oil shocks) changed consumer evaluations of the relative qualities of used cars in the U.S. during 1970–1981. We test the null hypothesis that the characteristics' coefficients remained constant over time. It is rejected if gasoline costs are excluded from the model but not if they are included. Alternative approaches are developed to show that the gasoline price increases alone can explain much of the observed changes in the coefficients.

Isolation and characterization of native human renin derived from Chinese hamster ovary cells

Abstract: Transfection of Chinese hamster ovary (CHO) cells with a plasmid containing the cDNA for human preprorenin has provided cell lines that secrete 15 mg of native prorenin per liter of culture medium. Tryptic activation of the prorenin occurs by selective cleavage of the Arg66-Leu67 bond (numbering as in preprorenin). The renin product, purified in a single step and in high yield by affinity chromatography, is fully stable for as long as 8 months when stored in solution at 4°C and pH 6.5. Purity of the renin was judged to be greater than 95% by gel electrophoresis, compositional and N-terminal sequence analyses, and specific enzyme activity. An important aspect of the present work is the development of a direct assay for renin which permits accurate and reproducible evaluation of enzyme units and kinetic parameters. Application of methods described herein, combined with appropriate scale-up fermentation capabilities, provides the means for generating gram quantities of human renin and its zymogen.

On a Global Existence Theorem of Small Amplitude Solutions for Nonlinear Wave Equations in an Exterior Domain.

Abstract: Soit Ω un domaine non borne dans un espace euclidien a n dimensions R n a frontiere compacte et C ∞ :∂Ω. On considere le probleme mixte Φ(u)=□u+F(t,x,D 1 D 1 u)=f(t,x) dans [0,∞)×Ω, u=0 sur [0,∞)×∂Ω, u(0,x)=u 0 (x), (∂ t u)(0,x)=u 1 (x) dans Ω, F est une fonction non lineaire a valeur reelle et D 1 D 1 u=(∂ t j ∂ x αu; 1≤j+|α|≤2)

Elimination of ethanol inhibition by perstraction.

Abstract: Perstraction (membrane-aided solvent extraction) was utilized for elimination of ethanol inhibition in continuous ethanol fermentation using high sugar concentrate Hollow fibers for an artificial kidney were used as a permeable membrane, and their capacity to extract ethanol was examined by using several organic solvents When tri-n-butylphosphate was used as an extractant, a 500 g/L feed glucose medium was successfully fermented by immobilized yeast cells During this continuous fermentation a high ethanol productivity of 48 g/hxL-gel was held, and the solvent requirement per consumed glucose was 6 L-solvent/kg-glucose

Immunohistochemical study on the development of serotoninergic neurons in the chick: II. Distribution of cell bodies and fibers in the spinal cord.

Abstract: The ontogenetic development of the serotoninergic system in the embryonic as well as in posthatching chick brain was studied with an indirect immunohistochemical technique with the aid of a specific antibody to serotonin (5-hydroxytryptamine). By embryonic day 4, rostral and caudal groups of serotonin-immunoreactive cell populations appeared in the mesencephalon and rostral and caudal rhombencephalon. At this stage, the rostral group had a considerable number of labelled cells that sent axons toward more rostral parts of brain, whereas the caudal group consisted of a small number of scattered serotonin-immunoreactive cells. The number of serotonin-positive cells increased with development, such that by embryonic day 8 almost all the serotoninergic cell groups found in the adult chick were already present. Serotoninergic-positive cells appeared in the paraventricular organ of the diencephalon as early as embryonic day 10. Judging from the cytoarchitectural organization of serotonin-immunoreactive cells, all of the serotoninergic cell groups in the chick brain seemed to be fully developed by embryonic day 16. On embryonic day 4, serotonin-immunoreactive fibers were found to enter into the marginal layer of the mesencephalon. Subsequently, serotonin-positive fibers ascended in the marginal layer of the brainstem up to the levels of the diencephalon and to the telencephalon on embryonic day 6 and 8, respectively. Serotonin-positive fibers, which first began to penetrate into the mantle layer on embryonic day 8, reached to the rostral pole of the telencephalon by embryonic day 10. In general, serotonin fibers were found in almost all brain regions by embryonic day 16. However, “terminal formation” in some nuclei did not seem to begin until the late embryonic or posthatching period. These observations indicate that the initial development of serotoninergic cell groups occurs during the first half of the 20th day of the incubation period of the chick. However, a longer time, ranging from early embryonic to posthatching stages, is necessary for the complete development of the serotoninergic projections.

Optical space-variant logic-gate array based on spatial encoding technique.

Abstract: A new optical logic operation technique is proposed that is based on spatial encoding and superposition of a decoding mask with the coded input patterns. Sixteen logical functions of two logical variables can be realized. In the present method, a space-variant logic operation is realized, that is, different logical operations are performed in parallel. The new method is the space-variant extention of the optical shadow-casting logic of Tanida and Ichioka, which is based on a space-invariant logic-gate array. Simple examples are given.