Showing papers by "Kyoto University published in 1981"

Hydrogen Peroxide is Scavenged by Ascorbate-specific Peroxidase in Spinach Chloroplasts

Abstract: Intact spinach chloroplasts scavenge hydrogen peroxide with a peroxidase that uses a photoreductant as the electron donor, but the activity of ruptured chloroplasts is very low [Nakano and Asada (1980) Plant & Cell Physiol. 21: 1295]. Ruptured spinach chloroplasts recovered their ability to photoreduce hydrogen peroxide with the concomitant evolution of oxygen after the addition of glutathione and dehydroascorbate (DHA). In ruptured chloroplasts, DHA was photoreduced to ascorbate and oxygen was evolved in the process in the presence of glutathione. DHA reductase (EC 1.8.5.1) and a peroxidase whose electron donor is specific to L-ascorbate are localized in chloroplast stroma. These observations confirm that the electron donor for the scavenging of hydrogen peroxide in chloroplasts is L-ascorbate and that the L-ascorbate is regenerated from DHA by the system: photosystem I-*ferredoxin-*NADP^>glutathione. A preliminary characterization of the chloroplast peroxidase is given.

A pharmacokinetic analysis program (multi) for microcomputer.

Abstract: A nonlinear least squares program (MULTI) for microcomputers was developed. The program is written in BASIC programming language. Four algorithms, (1) Gauss-Newton method, (2) damping Gauss-Newton method, (3) modified Marquardt method and (4) simplex method, can be used for nonlinear curve fitting in MULTI. Up to five pharmacokinetic equations, which are voluntarily defined by the user, are simultaneously fitted to observed time courses. The executions of MULTI are demonstrated for time courses of ampicillin and oxacillin in man.

Type C virus particles in a cord T-cell line derived by co-cultivating normal human cord leukocytes and human leukaemic T cells

Abstract: A recent nationwide survey of the lymphocyte subpopulations of leukaemia and lymphoma in Japan has disclosed a high incidence of adult T-cell leukaemia (ATL)1. One of the striking features of this disease is the clustering of patients in the southwestern part of Japan1,2. We have established a continuous culture line of leukaemic T cells from a patient with ATL3,4. This cell line, MT-1, was found to carry type C virus particles and ATL-associated antigens (ATLA) which specifically reacted with sera from all ATL patients and about 25% of healthy adults in the endemic area5. We report here that by co-culture of ATL cells from a female patient and normal human cord leukocytes from a male infant, a T-cell line of cord leukocyte origin was established. Numerous type C virus particles as well as ATLA were detected in this cell line.

Bend theory of river meanders. Part 1. Linear development

Abstract: Instability of the alternate-bar type in straight channels has long been identified as the cause of fluvial meandering. The condition of inerodible sidewalls, however, does not allow a meandering channel to develop. Herein a stability analysis of a sinuous channel with erodible banks allows for delineation of a ‘bend’ instability that does not occur in straight channels, and differs from the alternate-bar instability.In the case of alluvial meanders, the two mechanisms are shown to operate at similar characteristic wavelengths. This provides a rationale for the continuous evolution of alternate bars into true bends such that each bend contains one alternate bar.The same bend instability applies to incised meanders. A mechanism for incised alternate bars which differs from that for the alluvial case appears to operate at different characteristic wavelengths than that of bend instability. Analysis of data suggests that meandering in supraglacial meltwater streams is primarily due to the alternate bar mechanism, whereas the meandering of rills incised in cohesive material and of caves is likely due to the bend mechanism.The meander wavelength of incised reaches of meandering streams is often longer than that of adjacent alluvial reaches. An explanation is offered in terms of bend instability.

Kazhdan-Lusztig Conjecture and Holonomic Systems.

Abstract: In [7], D. Kazhdan and G. Lusztig gave a conjecture on the multiplicity of simple modules which appear in a Jordan-H61der series of the Verma modules. This multiplicity is described in the terms of Coxeter groups and also by the geometry of Schubert cells in the flag manifold (see [8]). The purpose of this paper is to give the proof of their conjecture. The method employed here is to associate holonomic systems of linear differential equations with R.S. on the flag manifold with Verma modules and to use the correspondance of holonomic systems and constructible sheaves. Let G be a semi-simple Lie group defined over • and g its Lie algebra. We take a pair (B,B-) of opposed Borel subgroups of G and let T=B~Bbe a maximal torus and W the Weyl group. Let b, b and f the corresponding Lie algebras and 9l the nilpotent radical of b. Let us denote by Jg the category of holonomic systems with R.S. on X=G/B whose characteristic varieties are contained in the union of the conormal bundles of Xw=BWB/B (we W). On the other hand, let (9 denote the category of finitely-generated U(g)-modules which are Tl-finite. By (gtrlv we denote the category of the modules in (9 with the trivial central character. We shall prove that J / / a n d (~trlv are equivalent by the correspondances S0l ~--*F(X;gJI) and M~--~,~| Here ~ is the sheaf of differential operators on X. Let us denote by M w the Verma module with highest weight -w(p)-p and let ~Jl w be the dual g -module of ~codimXwt/~ ~ Then, ~ w and Mw ~ [X~] ~,~X]\" correspond by the above correspondence. For any 9 J l e ~ , we can calculate the character of F(X; 93l) by the formula

Operator Approach to the Kadomtsev-Petviashvili Equation —Transformation Groups for Soliton Equations III—

Abstract: The hierarchy of Kadomtsev-Petvisahvili (KP) equation is studied on the basis of free fermion operators. Particular emphasis is laid on relating the operator approach to the Grassmann formulation of M. and Y. Sato. A new bilinear identity for wave functions is derived, and is shown to generate the series of Hirota bilinear equations for the KP hierarchy. Extension to the multicomponent case is also discussed.

Fatigue growth threshold of small cracks

Abstract: The effects of grain size and crack length on the threshold condition of fatigue growth of small cracks are analysed both theoretically and experimentally. The theoretical model is based on the assumption that the threshold condition is determined by whether the crack-tip slip band blocked by the grain boundary propagates into an adjacent grain or not. By comparing the model analysis with the experiments of mild steel, it was found that the threshold stress estimated from the fatigue limit of the smooth specimen gave the effective components of the applied stress. When the threshold stress normalized by the fatigue limit of the smooth specimen was correlated to the crack length normalized by a certain crack length, the theoretical relation was found to agree well with the experimental data. From a further analysis of the published data of various materials, the theoretical normalized relation was found to give a lower bound of the threshold values of the stress and the stress intensity factor. A deviation from the theoretical relation seen in the cases of hard metals was explained through an extension of the model by regarding that hard metals contained initial, inherent flaws even in the smooth specimen.

Structure of an Indian Summer Monsoon System with around 40-Day Period

Abstract: Through the analysis of the geopotential and wind fluctuation during the summer monsoon season over and around India, the predominant periodicity of about 40 days was confirmed especially in the lower and upper troposphere as a major active-break cycle of the monsoon activity. As well as the cloudiness fluctuation of the same period (Yasunari, 1979; Yasunari, 1980), these elements except the geopotential height in the upper level showed a marked northward propagation from the equator toward the Himalayan region. The geopotential height at 200 mb showed, in contrast, a standing oscillation over India. Cross-spectral analyses revealed that the vertical structure of the atmosphere is gradually modified during the northward phase shift of the anomaly cloudiness with the 40-day period. This modification is most apparent in the temperature field. The modification of the vertical structure from the south to the north over India seems to be attributed to the gradual enhancement of cumulus convection from the south to the north. It is also suggested that this cycle is caused by the periodical cold air outbreak over the middle and upper troposphere of the equatorial zone which may be associated with the index cycle of the westerly wave movements in the Southern Hemisphere. Finally, a multicell structure of the anomaly Hadley circulation regime over India through the Indian Ocean was proposed, which gives reasonable interpretations on various aspects of the active-break cycle of monsoon activity with this mode.

Nonlinear Picosecond-Pulse Propagation Through Optical Fibers with Positive Group Velocity Dispersion

Abstract: The predictions of the nonlinear Schrodinger equation have been tested by passing 5.5-psec optical pulses through a 70-m single-mode optical fiber. With use of a precise cross correlation technique based on pulse compressions, dramatic reshaping of the input pulses into flat-topped, frequency-broadened, and positively chirped 20-psec output pulses with self-steepened fall times of less than 2 psec was observed. The observations are in good agreement with theory.

Intraoperative radiotherapy: the Japanese experience.

Abstract: Clinical results of intraoperative radiotherapy ([OR) which have been obtained since 1964 in Japan were reviewed. In this radiotherapy a cancerocidal dose can be delivered safely to the lesions, since critical organs are shifted from the field so that the lesions may be exposed directly to radiation. Intraoperative radiotherapy has spread in Japan and the number of institutions in which this radiotherapy is performed has continued to increase to a total of 26 in 1979. The total number of patients treated was 717. It has been demonstrated that intraoperative radiotherapy has definite effects on locally advanced abdominal neoplasms and unresectable radioresistant tumors.

Structure of space-time correlations of bursting phenomena in an open-channel flow

Abstract: The present study is to investigate the structure of space-time correlations of bursting motions, such as ejections and sweeps in an open-channel flow, by a new conditional sampling analysis of the instantaneous velocity and Reynolds-stress signals measured simultaneously by two dual-sensor hot-film probes. One probe was fixed near the edge of the buffer layer, while the other probe was moved in the streamwise, vertical and spanwise directions. The sorted instantaneous Reynolds-stress signals obtained from the fixed probe were used as a detecting information of the occurrences of ejection or sweep events. The streamwise and vertical spatial characteristics of the ejection-sweep motions, and their convection process are investigated in detail. Also, the spanwise spatial properties of the high- and low-speed streaks in the bursting motions are examined experimentally by the present conditional sampling method.Next, a qualitative model is proposed which attempts to explain the space-time structures of the bursting phenomenon, on the basis of the above anemometry information and other visual observations.

Spleen colony-forming cell as common precursor for tissue mast cells and granulocytes

Abstract: The haematopoietic stem cells which produce colonies in the spleen of irradiated mice (CFU-S) can differentiate into erythrocytes, granulocytes, megakaryocytes and B lymphocytes. Although mast cell precursors are known to be present in the bone marrow, spleen, fetal liver and peripheral blood of mice, the relationship between the mast cell precursor and CFU-S has remained unclear. We have now made use of mice of two mutant genotypes to determine whether or not the tissue mast cell is a progeny of CFU-S. Giant granules of beige (C57BL/6-bg/bg, Chediak-Higashi syndrome) mice can be used for identification of the origin of both tissue mast cells and granulocytes, and WBB6F1-W/Wv mice are useful recipients because they lack tissue mast cells owing to a defect in mast cell precursors. We injected the cells from a single spleen colony into each WBB6F1-W/Wv mouse and demonstrated directly that the tissue mast cell is a progeny of CFU-S.

KP Hierarchies of Orthogonal and Symplectic Type–Transformation Groups for Soliton Equations VI–

Abstract: A series of new hierarchies of soliton equations are presented on the basis of the Kadomtsev-Petviashvili (KP) hierarchy. In contrast to the KP case, which admits GL( ∞) as its transformation group, these new hierarchies are shown to correspond to O( ∞) or Sp( ∞). Soliton, rational and quasi-periodic solutions are constructed.

A generalized proximal point algorithm for certain non-convex minimization problems

Abstract: An algorithm is presented for minimizing a function which is the sum of a continuously differentiable function and a convex function. The class of such problems contains as a special case that of minimizing a continuously differentiable function over a closed convex set. This algorithm may be viewed as a generalization of the proximal point algorithm to cope with non-convexity of the objective function by linearizing the differentiable term at each iteration. Convergence of the algorithm is proved and the rate of convergence is analysed.