Showing papers by "University of Tokyo published in 1976"
TL;DR: In this paper, a unified description of collective nuclear states in terms of a system of interacting bosons was proposed, and both the vibrational and the rotational limit can be recovered within this model.
1,093 citations
TL;DR: In this paper, the ground state of the d-dimensional Ising model with a transverse field is proven to be equivalent to the (d+ 1) -dimensional ising model at finite temperatures.
Abstract: The partition function of a quantal spin system is expressed by that of the Ising model, on the basis of the generalized Trotter formula. Thereby the ground state of the d-dimensional Ising model with a transverse field is proven to be equivalent to the (d+ 1) -dimensional Ising model at finite temperatures. A general relationship is established between the two partition functions of a general quantal spin system and the corresponding Ising model with many-spin interactions, which yields some rigorous results on quantum systems. Some applications are given.
875 citations
TL;DR: In this paper, new systematic approximants are proposed for exponential functions, operators and inner derivation, and remainders of the systematic approximation are evaluated explicitly, which give degrees of convergence of approximant.
Abstract: New systematic approximants are proposed for exponential functions, operators and inner derivation δ
H
. Remainders of systematic approximants are evaluated explicitly, which give degrees of convergence of approximants. The first approximant corresponds to Trotter's formula [1]: exp(A+B)=
$$\mathop {\lim }\limits_{n \to \infty } $$
[exp(A/n) exp(B/n)]
n
. Some applications to physics are also discussed.
626 citations
TL;DR: Two monkeys were trained to perform 3 kinds of spatial tasks (right-left DR, up-down DR, and conditional position discrimination with delay) and results indicate that there are two types of differential delay units.
381 citations
TL;DR: A simple and sensitive method was developed for the quantification of serum total 3alpha-hydroxy bile acids and a linear relationship was obtained between the amount of bile acid and the fluorescence intensities in the range of 1 to 150 mumol/1.
322 citations
TL;DR: The close relationship between the depth of the inverted T waves and the Apex/Mid wall thickness ratios suggests that the altered recovery process of the hypertrophied apical musculature is responsible for the giant T wave inversion of heretofore unsolved origin.
Abstract: Left ventricular scanning by echocardiography and ultrasono-cardiotomography was performed to search the possible muscular abnormality in 9 cases with giant T wave inversion without documented cause. The deeply inverted T wave was more than 1.2mV (average was 1.63mV) in the left precordial leads. All the cases had electrocardiographic left ventricular hypertrophy of obscure origin and ischemic episode was absent. Conventional echo beam direction to measure the short axis of the left ventricle disclosed almost normal thickness and movement of both interventricular septum (IVS) and the posterior wall (PW), so that the report of these cases is frequently within normal limits. However, ultrasono-cardiotomography (sector B scan) disclosed the fairly localized hypertrophy near the left ventricular apex, and conventional echocardiography also revealed the same area of either IVS or PW or both below the insertion of the papillary muscles, when the scanning towards the apex was performed (asymmetrical apical hypertrophy: AAH).Control study of 9 cases with IHSS showed asymmetrical septal hypertrophy (ASH) with almost equally hypertrophied IVS from base to apex. All cases had inverted T waves, but these were of lesser degree. Three cases had relatively deep T wave compatible with those of AAH, and these cases also had the apical hypertrophy of considerable degree (unusual type of IHSS, i.e., intermediate type between AAH and ASH).The close relationship between the depth of the inverted T waves and the Apex/Mid wall thickness ratios suggests that the altered recovery process of the hypertrophied apical musculature is responsible for the giant T wave inversion of heretofore unsolved origin. Until the connective link of AAH to the other forms of hypertrophic cardiomyopathy is disclosed, the cases with such a T wave and the apical hypertrophy may be designated as asymmetrical apical hypertrophy (AAH).
311 citations
TL;DR: The abundance of 15N in particulate organic matter in the euphotic layer of the North Pacific Ocean was investigated in this paper, where the 15N values ranged from −1.7 to +9.7% relative to atmospheric nitrogen.
257 citations
TL;DR: In this paper, the XPS spectrum of the valence band region of CrO2 is interpretable in terms of Goodenough's band-structure model, and the finite density of states at the Fermi level for this metallic compound is readily apparent.
232 citations
TL;DR: In this article, the electrical resistivity of ZnO doped with Al2O3 was measured in air and under reduced pressure (∼0.5 mm Hg) in the range from 30° to 680°C as a function of the degree of sintering.
Abstract: The electrical resistivity of ZnO doped with Al2O3 was measured in air and under reduced pressure (∼0.5 mm Hg) in the range from 30° to 680°C as a function of the degree of sintering. The data obtained were explained in terms of the effects of the microstructure of the sintered body and the chemisorbed oxygen. There are two mechanisms of electrical conduction involved, only one of which is affected by the microstructure.
219 citations
TL;DR: Microinjection experiments are reported that provide evidence of a cytoplasmic factor which induces germinal vesicle breakdown (GVBD), leading to the completion of oocyte maturation in the starfish Asterina pectinifera.
Abstract: IN starfish, the first maturation division of oocytes within an ovary is arrested at a late stage of prophase. It is resumed after stimulation by 1-methyladenine (1-MA) produced in the follicle cells under the influence of the gonadstimulating hormonal peptide, released from the nervous tissues1–3. 1-MA induces breakdown of the germinal vesicle and maturation of oocytes isolated in seawater2. When it causes maturation, 1-MA first acts on the oocyte surface4,5 to bring about cytoplasmic maturation, which is manifest in the acquisition of fertilisability6. The change in the cortical region of the oocyte under the influence of 1-MA is believed to produce a cytoplasmic factor which induces germinal vesicle breakdown (GVBD), leading to the completion of oocyte maturation. We now report microinjection experiments that provide evidence of such a cytoplasmic factor in the starfish Asterina pectinifera.
215 citations
TL;DR: Bisulfite is a reagent that meets in excellent fashion the requirements to serve as a probe of nucleic acid functions and structures and can be selectively transformed into uracil residues by the use of bisulfite.
Abstract: Publisher Summary This chapter discusses that nucleic acids are labile in solutions of extreme pHs and at high temperatures; the chemical modification must preferably be performed at a pH region around neutrality and at a temperature near 37°C or below. Chemical reactions that satisfy these requirements have been developed and used in nucleic acid studies. Bisulfite deaminates cytosine to give uracil. The reaction conditions are satisfactorily mild, and no deamination of adenine or guanine moieties takes place under the conditions employed. Although bisulfite does react with uracil and thymine under similar conditions, the bisulfite adducts formed are easily reverted to the parent pyrimidines. Therefore, cytosine residues in nucleic acids can be selectively transformed into uracil residues by the use of bisulfite. The most important feature of bisulfite reactions is their strict selectivity for the single-stranded regions of nucleic acids. Thus, bisulfite is a reagent that meets in excellent fashion the requirements to serve as a probe of nucleic acid functions and structures. In spite of the fact that the bisulfite reactions of nucleic acid components were discovered only several years ago, extensive studies of the reaction at the polynucleotide level have already been made and a number of applications reported. These involve (1) application for synthetic purposes, (2) studies on physical and biochemical properties of bisulfite-treated polynucleotides, (3) cross-linking of nucleic acid with protein, (4) chemical modifications of transfer RNA with the purpose of elucidating functional sites and conformations, and (5) induction of mutation in microorganisms.
TL;DR: A survey of theoretical and experimental work on piezo-and pyroelectricity of polymers can be found in this paper with a special emphasis on the origins of these properties.
Abstract: This article surveys theoretical and experimental work on piezo- and pyroelectricity of polymers in the 1970's with special emphasis on the origins of these properties. The origins are classified into three types: (A) internal strain (§2), (B) strain- and temperature-dependences of spontaneous polarization (§3), and (C) elastic and/or dielectric heterogeneity of a system with embedded charges (§4). The origin of piezo- and pyroelectricity of poly(vinylidene fluoride) is discussed as a typical example of electret (§5). Piezoelectric relaxations of polymers are discussed in some detail (§6). Methods of measurements of piezo- and pyroelectric constants of polymer films (§7) and applications of polymer films as new transducer materials (§8) are briefly reviewed.
TL;DR: In this article, the infrared spectroscopic study was made of NO and CO and their mixture adsorbed on rhodium metals supported on γ-alumina.
TL;DR: In this article, a carbondeflagration supernova model was proposed by using a full hydrodynamic computation, where a deflagration wave propagates through the core due to convective heat transport, does not grow into detonation.
Abstract: As an alternative to the carbon detonation, we present a carbondeflagration supernova model by a full hydrodynamic computation. A deflagration wave, which propagates through the core due to convective heat transport, does not grow into detonation. Though it results in a complete disruption of the star, the difficulty of overproduction of iron peak elements can be avoided if the deflagration is relatively slow.
TL;DR: The effect of removal of cilia is reported on the electro-physiological responses of paramecium to mechanical as well as some other stimuli.
Abstract: WHEN a paramecium collides with an obstacle, it reverses the direction of the effective stroke of its cilia, swims backwards for a while, and, with one or more repetitions of this ‘ciliary reversal’ response, avoids the obstacle1. When the medium is disturbed2 or when the posterior part of its body is stimulated mechanically, it swims faster than usual and escapes from the stimulus mainly by increasing the frequency of ciliary beat. The current view of the underlying mechanisms can be summarised as follows3,4. A mechanical stimulus to the anterior end of the animal deforms the cell membrane of this region, increasing the permeability to Ca2+ and causing a depolarisation which further activates the Ca2+-channels in the membrane. Thus, the depolarisation develops regeneratively towards the equilibrium potential of Ca2+. The Ca2+ which has entered the cell acts on some mechanism controlling the direction of ciliary beat to bring about ciliary reversal. On the other hand, a stimulus to the posterior end activates the K+-channels in the membrane, causing hyperpolarisation and an increase in ciliary beat frequency. Although the animal behaves as a mechanoreceptor cell in the early stages of these events, it is not clear which part of the cell transduces the mechanical stimulus to the activation of Ca2+- or K+-channels. We report here the effect of removal of cilia on the electro-physiological responses of paramecium to mechanical as well as some other stimuli.
TL;DR: An elastic protein from myofibrils is isolated which is clearly distinguishable from elastin or collagen, and the chemical entity responsible for the intracellular elasticity of muscle has remained obscure.
Abstract: IT has long been assumed that an elastic component other than extracellular collagen fibres is present in muscle fibres to explain their elastic properties, especially during passive stretch1,2 The presence of such an elastic component has been demonstrated in skinned fibres of frog skeletal muscle3,4. Furthermore, it has been observed that myofibrils after the removal of myosin are reversibly extended, indicating their structural continuity5. The chemical entity responsible for the intracellular elasticity of muscle has, however, remained obscure. When rabbit myofibrils were thoroughly extracted with salt solutions such as 0.6 M KI, it was noticed that remaining Z lines still maintained their continuity, although nothing could be seen between the adjacent Z lines under a phase microscope (compare ref. 6). Starting from this observation, we have been able to isolate an elastic protein from myofibrils which is clearly distinguishable from elastin or collagen.
TL;DR: In this paper, the magnetocrystalline anisotropy of low temperature phase of magnetite (Fe 3 O 4 ) was measured for a monoclinic single phase specimen by using computerized fully-automatic torque magnetometer.
Abstract: The magnetocrystalline anisotropy of low temperature phase of magnetite (Fe 3 O 4 ) was measured for a monoclinic single phase specimen by using computerized fully-automatic torque magnetometer. The anisotropy is expressed by \begin{aligned} E_{\text{a}}=K_{a}\alpha^{2}_{a}+K_{b}\alpha^{2}_{b}+K_{aa}\alpha^{4}_{a}+K_{bb}\alpha^{4}_{b}+K_{ab}\alpha^{2}_{a}\alpha^{2}_{b}-K_{u}\alpha^{2}_{111}, \end{aligned} where α a , α b and α 111 are direction cosines of the magnetization with respect to the monoclinic a -, b - and cubic [111] axes, respectively, the last of which coincides with the longest cube diagonal. The values of the anisotropy constants at 4.2 K are: K a =25.5, K b =3.7, K u =2.1, K a a =1.8, K b b =2.4 and K a b =7.0 in 10 5 erg/cm 3 . It was found that K a , K b and K u exhibit the temperature dependence of an activation type with the activation energy of about 0.02 eV. It was also found that the constants K a a , K b b and K a b are well expressed in terms of cubic K 1 . The mechanism of the an...
TL;DR: A means to avoid the glucose effect in the production of baker's yeast from glucose and/or molasses in a fed batch culture by controlling the feed rate of fresh medium with an ad hoc measurement of the respiratory quotient, RQ, is presented.
Abstract: A means to avoid the glucose effect in the production of baker's yeast from glucose and/or molasses in a fed batch culture by controlling the feed rate of fresh medium with an ad hoc measurement of the respiratory quotient, RQ, is presented. The feed rate is changed stepwise here such that the value of RQ ranges from 1.0 to 1.2 throughout the cultivation. Thus far, the specific growth rate based on the total cell mass and the growth yield obtained throughout are 0.24 hr-1 and 0.55 g cell/g glucose. Prior to the experimental run mentioned above, equations to predetermine the feed rate and concentration of glucose in the feed are derived from the mass balance of limiting substrates (glucose). Since values of either RQ or Io2 (Qo2 x, oxygen consumption rate with respect to the total cell mass in the fermenter) can be measured quite easily and reliably, computer control of the fermentation in light of this information is discussed.
TL;DR: In laboratory and field bioassays, Gnathotrichus sulcatus responded to sulcatol only when both enantiomers were present, and enantiomer-specific active sites on receptor proteins in the same or different cells are implicated.
Abstract: In laboratory and field bioassays, Gnathotrichus sulcatus responded to sulcatol (6-methyl-5-hepten-2-ol) only when both enantiomers were present. Response was greater to racemic sulcatol than to a mixture (65 : 35) of S-(+) and R-(-) enantiomers, the naturally occurring isomeric ratio. Enantiomer-specific active sites on receptor proteins in the same or different cells are implicated.
TL;DR: In this paper, the coesite-stishovite transition was determined over the temperature range 500-1100° C by means of in-situ X-ray measurements with NaCl as an internal pressure standard.
TL;DR: In this article, the repulsive potential energy between the ions i and j is specified by the nature of each ion as: (ρ i + ρ j ) exp[(ρ i+ ρ n − r) (ρ n + π j ) ] as a function of the interionic distance r. In this expression, qi and ρi are the ionic radius and ionic compressibility.
TL;DR: The release of substance P from rat hypothalamus is studied, and a potassium-evoked and calcium-dependent release of immunoreactive material is demonstrated, suggesting that metabolic degradation rather than tissue uptake is responsible for the inactivation of substanceP after its release from brain tissue.
Abstract: THE isolation and characterisation of the undecapeptide substance P from extracts of central nervous tissue has promoted renewed interest in the function of this compound in the central nervous system (CNS)1. Tn addition, the development of a sensitive and specific radioimmuno-assay2 and complementary immunohistochemical techniques3 has provided evidence for a differential distribution of substance P in the CNS4,5. Application of substance P to the spinal cord of neonatal rats has been shown to produce a potent depolarising action on motoneurones6. Elsewhere in the CNS iontopheric application of substance P elicits a characteristic neuronal excitation which although slow in onset is long lasting7–10. If substance P is to be considered as a neurotransmitter in the CNS, demonstration of its release from nerve terminals in response to physiological depolarisation is the next essential prerequisite11. We have therefore studied the release of substance P from rat hypothalamus, and have demonstrated a potassium-evoked and calcium-dependent release of immunoreactive material. In addition preliminary results suggest that metabolic degradation rather than tissue uptake is responsible for the inactivation of substance P after its release from brain tissue.
TL;DR: Diethyl phosphorocyanidate (DEPCA) as mentioned in this paper reacts with carboxylic acids in the presence of triethylamine leading to transient formation of acyl cyanides.
TL;DR: The results suggest that this syndrome might be induced by a cell-mediated autoimmune response to gangliosides.
TL;DR: In this paper, a density matrix reformulation of damping theory originally used for resonance fluorescence of atom is performed for a general system, by a time dependent description of resonance Raman scattering.
Abstract: Time dependent description of resonance Raman scattering is performed for a general system, by a density matrix reformulation of damping theory originally used for resonance fluorescence of atom. Radiative damping in the intermediate states can be described in terms of “damping operator” in realistic situations. In large ergodic systems, the scattering reduces to luminescence if the relaxation time within the excited states is much shorter than the radiative lifetime. In a typical case, time resolved emission spectra consist of various stages (i) scattering complex where absorption and emission are inseparable, (ii) dynamical and then (iii) kinetic relaxations giving rise to the hot luminescence, which finally converges to (iv) the ordinary luminescence from relaxed excited states. Hot luminescence does not appear within a motionally narrowed line. The interpretation of spectra depends also on the method of observation.
TL;DR: In this article, two interaction models were considered: uniform dilatation and constant volume method, where the potential of atoms infinitely separated is taken to be zero and the electron density is kept constant (constant volume method).
TL;DR: Very interesting results have been reported on its induction of certain types of gastric carcinomas, pancreatic tumors, and lung tumors that mimic the cases of human tumors.
Abstract: Publisher Summary Studies on chemical carcinogenesis have three main purposes. First is to elucidate carcinogenic mechanisms, second is to prevent possible carcinogenic hazard due to chemicals in the environment, and third is to provide clinical model systems in experimental animals. Recent studies on chemical carcinogens and mutagens have shown that, with a few exceptions, carcinogens are mutagenic and mutagens are carcinogenic. 4NQO is an example of a compound that has long been known to be both carcinogenic and mutagenic. In many studies, 4NQO has also been used as a positive control substance in mutagenic and carcinogenic experiments. 4NQO has been used in studies on cultured cells in vitro as well as on in vivo carcinogenesis. Very interesting results have been reported on its induction of certain types of gastric carcinomas, pancreatic tumors, and lung tumors that mimic the cases of human tumors. One advantage of using 4NQO as a carcinogen is that metabolic activation systems for it are commonly present in microbial and mammalian cells.
TL;DR: The properties of purified hydrogenase solubilized from particulate fraction of sonicated Desulfovibrio vulgaris cells are described, and these properties were very similar to those of clostridial hydrogenase, in spite of differences in the acceptor specificity and subunit structure.
Abstract: The properties of purified hydrogenase [EC 1.12.2.1] solubilized from particulate fraction of sonicated Desulfovibrio vulgaris cells are described. The enzyme was a brownish iron-sulfur protein of molecular weight 89,000, composed of two different subunits (mol. wt.: 28,000 and 59,000), and it contained 7-9 iron atoms and 7-8 labile sulfide ions. Molybdenum was not detected in the preparation. The absorption spectrum of the enzyme was characteristic of iron-sulfur proteins. The millimolar absorbance coefficients of the enzyme were about 164 at 280nm, and 47 at 400nm. The absorption spectrum of the enzyme in the visible region changed upon incubating the enzyme under H2 in the presence of cytochrome c3, but not in its absence. This spectral change was due to the reduction of the enzyme. The absorbance ratio at 400nm of the reduced and the oxidized forms of the enzyme was 0.66. The activity of the enzyme was hardly affected by metal-complexing agents such as cyanide, azide, 1,10-phenanthroline, etc., except for CO, which was a strong inhibitor of the enzyme. The activity was inhibited by SH-reagents such as p-chloromercuribenzenesulfonate. The enzyme was significantly resistant to urea, but susceptible to sodium dodecyl sulfate. These properties were very similar to those of clostridial hydrogenase [EC 1.12.7.1], in spite of differences in the acceptor specificity and subunit structure.