Showing papers by "Kyoto University published in 1977"

Poly(ADP-ribose) and ADP-ribosylation of proteins.

Abstract: Publisher Summary This chapter analyzes poly(ADP-ribose) and ADP-ribosylation of proteins. Poly(ADP-ribose) and the ADP-ribosylation of proteins constitute a novel type of covalent modification of proteins. They are ubiquitously distributed in nature and are implicated in the regulation of cell proliferation, protein synthesis, and DNA as well as RNA metabolism. This type of post-translational modification is unique because NAD, nicotinamide adenine dinucleotide, whose primary function is an electron carrier in biological oxidation, invariably provides the ADP-ribosyl moiety, which is transferred on to a protein molecule. The ADP-ribosyl unit thus, covalently attached to a protein acceptor is present as either a monomer or a polymer as in the case of the nuclear system. This chapter also summarizes developments in this field of research and some experimental results. It reviews briefly, mono ADP-ribosylation of proteins, in which only a single ADP-ribosyl moiety is transferred to a protein acceptor. It also covers a more complex reaction, poly(ADP-ribose) in nuclei, in which the ADP-ribosyl units are polymerized.

Prediction of the contributions to the Reynolds stress from bursting events in open-channel flows

Abstract: In this paper we intend to predict the magnitude of the contribution to the Reynolds stress of bursting events: ‘ejections’, ‘sweeps’, ‘inward interactions’ and ‘outward interactions’. We shall do this by making use of the conditional probability distribution of the Reynolds stress − uv, which can be derived by applying the cumulant-discard method to the Gram-Charlier probability distribution of the two variables u and v. The Reynolds-stress fluctuations in openchannel flows over smooth and rough beds are measured by dual-sensor hot-film anemometers, whose signals are conditionally sampled and sorted into the four quadrants of the u, v plane by using a high-speed digital data processing system.We shall verify that even the third-order conditional probability distribution of the Reynolds stress shows fairly good agreement with the experimental results and that the sequence of events in the bursting process, i.e. ejections, sweeps and interactions, is directly related to the turbulent energy budget in the form of turbulent diffusion. Also, we shall show that the roughness effect is marked in the area from the wall to the middle of the equilibrium region, and that sweeps appear to be more important than ejections as the roughness increases and as the distance from the wall decreases.

Antiferro-Ferrimagnatic Transition in Triangular Ising Lattice

Abstract: Molecular field approximation is applied to a triangular Ising lattice with antiferromagnetic nearest neighbor interaction J and ferromagnetic second neighbor interaction J ' to study the magnetic behavior at finite temperatures. In the range of 0> J '/ J >-0.8, with increasing temperature the system is found to have a second-order transition from a ferrimagnetic state to an antiferromagnetic state in which one of three sublattices is completely disordered. Another second-order transition occurs in the ferrimagnetic state. Magnetic structure factor, free energy, magnetic specific heat, differential magnetic susceptibility as well as sub-lattice magnetization are calculated numerically with parameter J '/ J . Critical magnetic field of first-order transition from antiferromagnetic state to ferrimagnetic state is also evaluated. Discussion is given in connection with magnetic ordering in CsCoCl 3 and CsCoBr 3 .

Structure of the Excited States in 12C. II

Abstract: Structure of both positive- and nCc:gative-parily slates in 12C is studied with a microscopic :l u-parlicle model. The c.m. motions of 3 a-clusters are treated by the generator coordinate method. All the levels with T=O below 15 MeV (except the 1:0.7 MeV r+ level) are suc­ cessfully reproclucecl, including the famous o,+ level and the next positive-parity level which is regarded as :o,+. Another 2', :l1+ and two 4+ stales which have a structure quite similar to that of the O, ,_ and :0, + stales are preclictecl with large K-rnixings. Furthermore the pre­ sent investigation predicts an existence of O, + state. The structure of all the above excited positive-parity slates is quite diiferenl from that expected in the shell model, hut rather should he considered that· o£ a finite a-boson ga,. The negative-parity leveis are quite well de":ribecl '" memhcrs of the K"=:l- and I bands in the present model. § 1. Introduetion The nucleus "C has been offering a testing field to vanous nuclear models. It is a stable and tight binding system though it is one of the lightest nuclei. On the assumption of a stable average nuclear Jield, shell model \Vas applied in se\·eral \·ersions to explain low energy properties of 12C.'' Unfortunately, all the efforts have resulted in obtaining only partial success. Above all the second 0 t level at 7.7 MeV and the next positive-parity level at 10.3 MeV have been difficult to be reproduced at such low excitation energies. They are also known to have anomalously large a-decay widths.'' Morinaga suggested that they form an excited rotational band with a linear chain structure of 3 a-particles. 11 According to Ikeda's cliagram5l' 61 one can expect appearance of nuclear states with some cluster structure in the neighbourhood o£ decay-threshold energies of a-particles. In 12C, the 0,' le\·el and the next positive-parity level noted aboYe are expected to be such states, that is, to ha\·e distinct cluster structure relevant to the 'Be -1--CY channel al 7.4 MeV. From the \'iewpoint of a-particle mudel this nucleus has been investigated since the early ages of nuclear study. The classical a-particle model was applied to it on the analogy o£ homonuclear tri-atomic mole­ cule." The modeL howeYer, predicts a :3 state at too low an excitation energy compared with experiment. This dr;cm·back is known to disi!ppear in the micro­ scopic model.RJ Recently sc1·eral dynamical calculations"' of :3 a-particle system haYe been made by the use of 1·arious a-ct interactions. Fuji\\'ara and Tamagaki 9b 1 11 Preliminary results were

Nonlinear Evolution Equations Generated from the Bäcklund Transformation for the Boussinesq Equation

Abstract: A Backlund transformation for the Boussinesq equation is given in the bilinear form. It is shown that the Backlund transformation generates an important class of nonlinear evolution equations exhibiting N-soliton solutions. They are a modified Boussinesq equation, a higher order water wave equation introduced by Kaup and a coupled equation whose N-soliton solution reduces to that of the nonlinear Schrodinger equation with normal dis­ persion. The relation between the Backlund transformation and the inverse scattering method is also discussed.

Lattice imaging of a grain boundary in crystalline germanium

Abstract: A high-angle tilt grain boundary viewed end-on in a (011) thin crystal of Ge has been imaged with atomic resolution in the Kyoto 500 kV electron microscope. The boundary is shown to consist of alte...

Efferent projections of the pretectum in the cat

Abstract: Direct projections from the pretectum in the cat were investigated by means of the Nauta-Gygax and the Fink-Heimer method in an attempt to identify the morphological substrates subserving possible neural mechanisms involved in visual behaviour and reflexes.

Spontaneous and ethyl methanesulfonate-induced mutations controlling viability in drosophila melanogaster. iii. heterozygous effect of polygenic mutations

Abstract: Spontaneous and EMS-induced mutations were accumulated for several generations on the second chromosome of Drosophila melanogaster by keeping this chromosome heterozygous under conditions of minimal natural selection. This article reports studies of heterozygous effects of these mutants.—Both lethal and mildly deleterious mutants have a deleterious heterozygous effect. There was no discernible difference between heterozygotes in which all the mutants were on one chromosome and those where the mutants were distributed over both homologs; thus the coupling-repulsion effect of Mukai and Yamazaki (1964, 1968) is not confirmed. The spontaneous polygenic mutants have a dominance of 0.4 to 0.5, and the same value is found at very low EMS doses. However, the value at higher EMS doses is only about half as high. Since the low doses have a large fraction of spontaneous mutants, the dominance of EMS mutants is less, in the range 0.1 to 0.3, but still larger than for lethals.

Products formed by photosensitized oxidation of unsaturated fatty acid esters

Abstract: Photosensitized oxidation of unsaturated fatty acid methyl ester was carried out using methylene blue as a sensitizer. Oxidation products, monohydro-peroxides, were identified as trimethylsilyl derivatives. Methyl oleate gave the 9- and 10-isomers; methyl linoleate, the 9-, 10-, 12-, and 13-isomers; and methyl linolenate, the 9-, 10-, 12-, 13-, 15-, and 16-isomers, respectively. The double bond to which the hydroperoxide group attached was shifted to the adjacent position in each isomer. Thus, both conjugated and nonconjugated isomers were present in methyl linoleate monohydroperoxides and methyl linolenate monohydroperoxides. By the inhibition experiment, it was ascertained that the above reaction proceeded via singlet oxygen. The relative rates of methyl oleate, methyl linoleate, and methyl linolenate were 1.0∶1.7∶2.3, respectively. These results obtained from the methyl esters were applied to the photosensitized oxidation of triglycerides purified from vegetable oils, and the reaction mechanism on triglycerides was proposed.

The Power of Dominance Relations in Branch-and-Bound Algorithms

Abstract: A dominance relation D is a binary relation defined on the set of partial problems generated in a branch-and-bound algorithm, such that PiDPj (where Pi and Pj are partial problems) implies that Pj can be excluded from consideration without loss of optimality of the given problem if Pi has already been generated when Pj is selected for the test. The branch-and-bound computation is usually enhanced by adding the test based on a dominance relation.A dominance relation D′ is said to be stronger than a dominance relation D if PiDPj always implies PiD′Pj. Although it seems obvious that a stronger dominance relation makes the resulting algorithm more efficient, counterexamples can easily be constructed. In this paper, however, four classes of branch-and-bound algorithms are found in which a stronger dominance relation always gives a more efficient algorithm. This indicates that the monotonicity property of dominance relations would be observed in a rather wide class of branch-and-bound algorithms, thus encouraging the designer of a branch-and-bound algorithm to find the strongest possible dominance relation.

A Heuristic Method for Determining Optimal Reliability Allocation

Abstract: The paper presents a method for obtaining an optimal reliability allocation of an n-stage series system. In each stage, redundant comnponents can be added (in parallel, stand-by, or k-out-of-n:G, etc.), or a more reliable component can be used in order to improve the system reliability. The solution is obtained by repeatedly using a more reliable candidate at each stage that has the greatest value of a `weighted sensitivity function'. The balance between the objective unction and the constraints is controlled by a `balancing coefficient'. The overall computational procedure is given and an example is presented. The computations are given for a set of randomly generated test problems in which the optimal parallel redundancy under linear onstraints is determined. The proposed method is then compared with other methods.

Theory of the ionization of the hydrogen atom by an external electrostatic field

Abstract: The theory of the field ionization of the hydrogen atom is developed analytically. The leading term of an asymptotic expansion for the ionization rate---the reciprocal lifetime---is derived. In the weak-field limit, the formula for the ionization rate reduces to $\frac{1}{\ensuremath{\tau}}={n}^{\ensuremath{-}3}{[{n}_{2}!({n}_{2}+|m|)!]}^{\ensuremath{-}1} {(n\frac{^{3}F}{4})}^{\ensuremath{-}2{n}_{2}\ensuremath{-}{|m|}_{\ensuremath{-}1}}\ifmmode\times\else\texttimes\fi{}\mathrm{exp}[3({n}_{1}\ensuremath{-}{n}_{2})\frac{\ensuremath{-}2}{(3n^{3}F)}]$, where $n$, $m$, and ${n}_{1}$ and ${n}_{2}$ are the usual principal, magnetic, and parabolic quantum numbers, respectively, and $F$ is the field strength in atomic units. For the ground state, this formula agrees with that of Landau and Lifshitz. For all ${m}^{2}=1$ states, the formula agrees asymptotically for large ${n}_{2}$ with that of Lanczos after correction of the latter for an error. It is in disagreement with the result of Oppenheimer and with the low-field result of Rice and Good. Significantly better agreement with numerical calculations of Alexander, of Hehenberger, McIntosh, and Br\"andas, of Damburg and Kolosov, and of Bailey, Hiskes, and Riviere is obtained with a formula for not quite such small $F$, $\frac{1}{\ensuremath{\tau}}={(\ensuremath{-}2\mathrm{Re}E)}^{\frac{3}{2}}{[{n}_{2}!({n}_{2}+|m|)!]}^{\ensuremath{-}1}{f}^{\ensuremath{-}B}\mathrm{exp}[\ensuremath{-}\frac{1}{(6f)}]$, where $E$ is the perturbed energy, where $f=\frac{[{(\ensuremath{-}2E)}^{\ensuremath{-}\frac{3}{2}}F]}{4}$, and where $\frac{B}{2}={\ensuremath{\beta}}_{2,{n}_{2}}$ is the usual perturbed separation constant [${\ensuremath{\beta}}_{2}\ensuremath{\rightarrow}\frac{{n}_{2}+|m|}{2}+\frac{1}{2}$, as $F\ensuremath{\rightarrow}0$].