Showing papers by "University of Tokyo published in 1980"

Novel method for high resolution measurement of laser output spectrum

Abstract: The spectral spread of the best stabilised semiconductor lasers has been reduced to several megahertz. Conventional spectroscopy techniques cannot offer a spectral resolution fine enough for measuring such a sharp spectrum. The letter proposes a novel method by which 50 kHz resolution can be obtained. The principle, experimental set-up and results are described.

Thermostability and aliphatic index of globular proteins.

Abstract: A statistical analysis shows that the aliphatic index, which is defined as the relative volume of a protein occupied by aliphatic side chains (alanine, valine, isoleucine, and leucine), of proteins of thermophilic bacteria is significantly higher than that of ordinary proteins. The index may be regarded as a positive factor for the increase of thermostability of globular proteins.

the contact area and pressure distribution pattern of the knee: A study of normal and osteoarthrotic knee joints

Abstract: Seven knees were studied to determine the contact area and pressure distribution of the tibiofemoral joint, under various loads and at 0° flexion, using the casting method and special sensor sheets. At a load of 1000N (Newton) the contact area of the knee was 11.5 × lCmm2 with menisci and 5.2 × lCmm2 without menisci, and the menisci occupied 70 per cent of the total contact area. Peak pressure at 1000N was 3MPa (Mega Pascal) with the menisci and 6MPa without them. the high pressure areas were located on the lateral meniscus as well as on the uncovered part of the articular cartilage of the lateral compartment, and on the uncovered cartilage in the medial compartment. After removal of the menisci the contact area decreased to below one half that of the intact knee and the contact pressure considerably increased. These facts imply that the menisci have load bearing and load spreading functions.The contact areas were also measured in two osteoarthrotic knees and they were significantly larger than those in n...

Optical Turbulence: Chaotic Behavior of Transmitted Light from a Ring Cavity

Abstract: It is theoretically shown that the transmitted light from a ring cavity containing a nonlinear dielectric medium undergoes transition from a stationary state to periodic and nonperiodic states, when the intensity of the incident light is increased. The nonperiodic state is characterized by a chaotic variation of the light intensity and associated broadband noise in the power spectrum. The experimental possibility of observing such a transition is also discussed.

Path integral for gauge theories with fermions

Abstract: The Atiyah-Singer index theorem indicates that a naive unitary transformation of basis vectors for fermions interacting with gauge fields is not allowed in general. On the basis of this observation, it was previously shown that the path-integral measure of a gauge-invariant fermion theory is transformed nontrivially under the chiral transformation, and thus leads to a simple derivation of "anomalous" chiral Ward-Takahashi identities. We here clarify some of the technical aspects associated with the discussion. It is shown that the Jacobian factor in the path-integral measure, which corresponds to the Adler-Bell-Jackiw anomaly, is independent of any smooth regularization procedure of large eigenvalues of $D$ in Euclidean theory; this property holds in any even-dimensional space-time and also for the gravitational anomaly. The appearance of the anomaly and its connection with the index theorem are thus related to the fact that the primary importance is attached to the Lorentz-covariant "energy" operator $D$ and that $D$ and ${\ensuremath{\gamma}}_{5}$ do not commute. The abnormal behavior of the path-integral measure at the zero-frequency sector in the presence of instantons and its connection with spontaneous symmetry breaking is also clarified. We comment on several other problems associated with the anomaly and on the Pauli-Villars regularization method.

Mechanism of Yellow Luminescence in GaN

Abstract: The mechanism of the yellow luminescence in GaN has been studied. The yellow band is observed in microcrystals synthesized from Ga and NH3 by direct reaction, but is not observed in needle-like crystals grown by sublimation-recrystallization. Doping with carbon emphasizes the yellow band. The characteristic excitation band is observed in C-doped GaN. The yellow band is due to a radiative transition from a shallow donor with a depth of 25 meV to a deep acceptor with a depth of 860 meV. The relation between the characteristic excitation band and the emission band is interpreted by the simple configuration coordinate model. The deep acceptor is thought to be a complex consisting of a gallium vacancy and a carbon atom substituted for a nearest neighbour of the gallium sites.

Load-bearing mode of the knee joint: physical behavior of the knee joint with or without menisci.

Abstract: The load-bearing mode of the knee joint and the load-carrying capacity of the menisci were investigated by a load-deflection and load-contact study using stresses of as much as 3 times body weight on 14 freshly amputated knee specimens. A flection angle of 0 degrees was used. The average deflection and the average size of the contact area of the intact knees were 1.04 x 10(-1) cm and 14.1 cm2 respectively when the knees were loaded to 1,500 N. The elastic modulus of the entire joint was 2.7 x 10(2) MPa over the load of 1,500 N. At first, the knee joint was not congruous at a low load under about 500 N; the joint contacts both menisci in conjunction with some part of the exposed cartilage. However, the joint became markedly congruous at higher loads, around 1,000 N. The joint was in contact with the menisci and the exposed cartilage, and as more load was applied, the areas of contact widened to the peripheral areas of both the compartments. After menisci were removed, the deflection increased. The size of the contact areas decreased significantly by a third to a half. Consequently, the average stress increased 2 to 3 times that of the intact knee. The elastic modulus was increased over 2 fold after menisci were removed. The results of the energy study indicate that the menisci gave more elastic stability to the joint. After the menisci were removed, more energy was dissipated during cyclic loading. Thus, the menisci provide surface compliance and serve to transmit stresses across the wider areas to the periphery, and, therefore, help to avoid stress concentration both in the articular cartilage and in the subchondral bone, especially under high loads over 1,000 N.

A glycolipid on the surface of mouse natural killer cells

Abstract: Cytotoxic treatment with rabbit antiserum raised against purified glycosphingolipid "asialo GM1" was capable of eliminating natural killer (NK) activity of spleen cells from different inbred mouse strains including CBA/J, C57BL/6, BALB/c, AKR, and athymic nude mice. The anti-asialo GM1 antiserum showed little cross-reactivity with structurally related glycolipids, e.g. GM), GD 1 b and asialo GM2 in the microflocculation test. The specific reactivity of this antiserum with NK cells was confirmed by the quantitative absorption of anti-NK activity with graded amounts of asialo GM1 but not with other glycosphingolipids. The absorption of anti-brain-associated T cell antigen (anti-BAT) with asialo GM1 also effectively diminished its anti-NK activity, leaving the ability to kill T cells intact. This suggests that the antibody to asialo GM1 is responsible for the anti-NK activity contained in the anti-BAT antiserum. In contrast to the extreme sensitivity of NK cells to anti-asialo GM1, alloreactive cytotoxic T killer cells generated in the mixed lymphocyte culture were not killed by anti-asialo GM1 and complement. These results indicate that asialo GM1 is expressed on mouse NK cells in a high concentration.

Establishment of an Experimental System for the Study of Tracheary Element Differentiation from Single Cells Isolated from the Mesophyll of Zinnia elegans.

Abstract: Single cells were isolated mechanically from the mesophyll of adult plants and of seedlings of Zinnia elegans L. cv. Canary bird. When single cells isolated from the first leaves of seedlings were cultured in a liquid medium in the dark with rotation, they differentiated to tracheary elements with a reasonable degree of synchrony in the 24-hour period between days 2 and 3 after culture. The proportion of tracheary elements as a percentage of total cells reached nearly 30% 3 days after culture. Factors favoring cytodifferentiation were certain optimum levels of both alpha-naphthalene-acetic acid (0.1 milligram per liter) and benzyladenine (1 milligram per liter), a low concentration of ammonium chloride (0 to 1 millimolar), and an initial cell population density in the range 0.4 to 3.8 x 10(5) cells/ml. It was possible to follow analytically the sequence of cytodifferentiation in individual cells in this system.

On the equations of fully fluidized granular materials

Abstract: Equations for fully fluidized granular materials are proposed and are solved in a simple case. In fully fluidized granular materials, the granular particles slip or collide with each other and energy is dissipated. In describing the energy dissipation process characteristic to granular materials, a measure of random motion of granular particles is introduced as a new internal variable. We derive the constitutive equations by using a simple kinematical model of the collision of particles. The set of equations for fully fluidized granular materials obtained has properties similar to the equations that describe turbulence. For reasonable assumptions, these equations predict the results of Bagnold, namely that the shear and normal stress depend upon the square of the velocity gradient. In case of steady one-dimensional gravity flow the calculated flow profiles resemble experimental ones.

Structural defects in amorphous solids A computer simulation study

Abstract: A definition of structural defects in amorphous solids in terms of the distribution of the internal stresses on the atomic level and of the symmetry of the environment of individual atoms is introduced. This definition does not require an ideal reference structure. The concept of the internal stresses on the atomic scale has been previously applied to describe the core structure of crystalline dislocations. In this paper it has been applied to the model amorphous structure generated by a computer simulation. It was found that there is a significant variation in the magnitude and direction of internal stresses, and that there are regions of 10 to 20 atoms over which the stresses remain either high or low. A method of calculating the symmetry coefficients at atomic sites has been proposed, and applied to the same system. It has been shown that there are significant correlations between the internal stresses and the local symmetry. The low-stress, high-symmetry regions resemble microcrystalline clus...

Self-consistency and sum-rule tests in the Kramers-Kronig analysis of optical data: Applications to aluminum

Abstract: An iterative, self-consistent procedure for the Kramers-Kronig analysis of data from reflectance, ellipsometric, transmission, and electron-energy-loss measurements is presented. This procedure has been developed for practical dispersion analysis since experimentally no single optical function can be readily measured over the entire range of frequencies as required by the Kramers-Kronig relations. The present technique is applied to metallic aluminum as an example. The results are then examined for internal consistency and for systematic errors by various optical sum rules. The present procedure affords a systematic means of preparing a self-consistent set of optical functions provided some optical or energy-loss data are available in all important spectral regions. The analysis of aluminum discloses that currently available data exhibit an excess oscillator strength, apparently in the vicinity of the L edge. A possible explanation is a systematic experimental error in the absorption-coefficient measurements resulting from surface layers: possibly oxides: present in thin-film transmission samples. A revised set of optical functions has been prepared by an ad hoc reduction of the reported absorption coefficient above the L edge by 14%. These revised data lead to a total oscillator strength consistent with the known electron density and are in agreement with dc-conductivity and stopping-power measurementsmore » as well as with absorption coefficients inferred from the cross sections of neighboring elements in the periodic table. The optical functions resulting from this study show evidence for both the redistribution of oscillator strength between energy levels and the effects on real transitions of the shielding of conduction electrons by virtual processes in the core states.« less

Spectroscopic studies on doped polyacetylene and β-carotene

Abstract: In order to elucidate the structural details of doped polyacetylene (a highly conducting organic polymer), the optical absorption, Raman, and infrared spectra of not only trans‐(CH)x doped with iodine, AsF5, and SO3 but also β‐carotene doped with iodine and SO3 were studied. The infrared spectra of two kinds of isotopically substituted polyacetylenes (CD)x and (13CH)x doped with iodine were also observed. Analysis of the experimental results shows that upon doping each of the four vibrational branches (ν1–ν4) in the 1600–900 cm−1 region of a polyene chain splits into two groups, namely, the higher frequency group and the lower frequency one. The former group consists of the ’’gerade’’ vibrations of polyene parts which are not directly attacked by dopants but are perturbed along the chain, whereas the latter is made up of the ’’ungerade’’ vibrations of the positively charged polyene part with the doped site at its center. The Raman bands in the higher‐frequency group of ν1 (mainly the C=C stretching mode) ...

Three-dimensional displays

Abstract: Three-dimensional display techniques can be classified as binocular and autostereoscopic types, still and animated types, nontransmitted and transmitted types, and nonholographic and holographic types. This paper deals mainly with autostereoscopic still nontransmitted techniques. Holographic and nonholographic tecniques are described on about equal footing. For the sake of brevity, emphasis is placed upon those techniques that appeared in the past several years. However, some old techniques of historical and/or practical importance are also mentioned because rather few textbooks are available in this field. In the final part, state of the art of three-dimensional display for animated and transmitted images (three-dimensional television) is described. Speculations on the direction of the development are presented.

Multi‐institutional Study on the Teratogenicity and Fetal Toxicity of Antiepileptic Drugs: A Report of a Collaborative Study Group in Japan

Abstract: Summary: A multi-institutional collaborative study was conducted concerning the course of pregnancy and delivery and the incidence of abnormal infants delivered of epileptic women. Of 657 women receiving antiepileptic drugs, 73% delivered live infants, 14% had miscarriage or stillbirth, and 13% underwent induced abortion. In contrast to the above findings, 80% of 162 patients not receiving antiepileptic drugs delivered live infants and 4% had miscarriage or stillbirth. The latter outcome was significantly increased in the medicated patients. In this series, 63 (9.9%) of 638 live births were malformed, 55 (11.5%) being from medicated mothers and 3 (2.3%) from nonmedicated mothers. The incidence of fetal malformation in medicated mothers was thus five times as high as that in nonmedicated mothers. Cleft lip and/or palate and malformations involving the cardiovascular system were found frequently in the infants from medicated mothers. General background factors that might exert teratogenic effects on pregnant patients with epilepsy were studied, and the potential toxicity of antiepileptic drugs to the fetus was also analyzed. In this regard, consideration should be given to whether the patient has partial epileptic seizures, whether the patient herself exhibits any malformation, or whether her previous pregnancy resulted in an abnormal outcome. The incidence of fetal malformation was the highest (12.7%) in the medicated patients who had epileptic seizures during the pregnancy. It is presumed on the basis of the results of analysis of the data that a combination of more than three drugs and a daily dose greater than a certain minimal level is likely to produce malformed infants. ZUSAMMENFASSUNG In vielen Institutionen wurde eine kollaborative Studie uber den Verlauf der Schwangerschaft, der Geburt und die Haufigkeit von Abnormitaten bei Kin-dern von Schwangeren mit Epilepsie durchgefuhrt. 73% der 657 Frauen unter antiepileptischer Therapie bekamen lebende Kinder, 14% hatte eine Fehl- oder Totgeburt und bei 13% wurde ein Abort eingeleitet ImGegensatz zu diesen Ergebnissen hatten 80% von 162 Patienten ohne Antiepileptica Lebendgeburten, 4% eine Fehloder Totgeburt. Die letztere war signifikant hoher bei den Patientinnen, die Antiepileptica erhielten. In dieser Serie waren 63 von 638 Lebendgeburten (9.9%) miRbildet, 55 (1 1.5%) stammten von therapier-ten Muttern, 3 (2,3)%) von nicht therapierten Muttern. Die Haufigkeit fetaler Fehlbildungen bei therapierten war 5mal hoher als bei nicht therapierten Muttern. Lippen- und/oder Gaumenspalte und MiRbildungen im kardiovaskularen Bereich wurden haufig bei Kindern therapierter Mutter gefunden. Die allgemeinen Hintergrundsfaktoren, die einen teratogenen EinfluR auf Schwangere mit Epilepsie ausuben konnten, wurden untersucht und die mogliche Toxicitat der Antiepileptica auf den Fetus analysiert. In diesen Untersuchungen sollte berucksichtigt werden, ob der Patient fokale epileptische Anfalle hat, o b e r selbst eine MiDbildung hat oder ob fruhere Schwangerschaften abnorm endeten. Die Haufigkeit der fetalen Fehlbildungen war am groRten (12.7%) bei therapiertenPatienten, die epileptische Anfalle wahrend der Schwangerschaft bekamen. Aufgrund dieser Resultate wird angenommen, daR die Kombination von mehr als 3 Medikamenten und eine tagliche Dosierung oberhalb eines Grenzwertes wahrscheinlich zu fehlgebildeten Kindern fuhren.

Maternal Expectations For Mastery of Developmental Tasks In Japan And The United States

Abstract: Maternal expectations about development help organize parental behavior by providing internal referents against which a child's growth and behavior are evaluated, thus identifying occasions for intervention by the adult. Fifty-eight mothers from Japan and 67 mothers from the United States were interviewed about the ages at which they expected their four-year-old children to acquire a number of specific developmental skills. There were no differences between the two groups of mothers in mean age of mastery expectation across all 38 items but Japanese mothers expected early mastery on skills that indicated emotional maturity, self-control, and social courtesy. Mothers in the U.S. expected mastery at an earlier age on items indicating verbal assertiveness and social skills with peers. Maternal expectations were found to correlate with children's performance on tests of school aptitude when the children were six years of age.

Increase in insulin response after treatment of overt maturity-onset diabetes is independent of the mode of treatment.

Abstract: The changes in insulin response to a 100 g glucose tolerance test after treatment by diet, sulphonylurea and insulin were compared in non-ketotic diabetic patients who had fasting blood glucose concentrations higher than 160 mg/100 ml. Patients were selected so that their pre-treatment and post-treatment blood glucose levels were comparable between different treatment groups. Their insulin responses were poor initially but increased significantly when the diabetic state was improved by each treatment. The degree of improvement of insulin response was similar between different treatment groups, when their fasting blood glucose decreased below 140 mg/100 ml and the glucose tolerance curves were improved to a similar extent. Preand post-treatment ∑ IRI values (sum of insulin values during glucose tolerance test, mean±SD) were 102±50 and 200±37 μU/ml in diet-treated group (n = 28), 90±40 and 195±53 μU/ml in sulphonylurea-treated-group (n=48), and 83±28 and 193±38 μU/ml in insulin-treated group (n = 13), respectively. The data suggest that the poor insulin response in overt diabetes results not only from an inherent insensitivity of B-cells to glucose but also from the metabolic derangement of diabetes. Poor insulin response and overtly diabetic metabolism seems to form a vicious cycle.

15 N natural abundance in oceanic suspended particulate matter

Abstract: Particulate organic matter (POM) has a central role in the vertical transport of material in the sea1. In the open ocean, POM is produced in the euphotic layer by phytoplankton and degraded in the aphotic layer during sinking to the sea floor. Isotopic abundance of biophilic elements such as C and N in POM is altered by isotopic fractionations associated with biochemical reactions2. Natural abundances of 13C or 15N thus provide useful information on biochemical behaviour of POM in the sea. We report here the first comprehensive data on the vertical distribution of 15N in suspended POM3 collected at a station in the northeastern Indian Ocean. Also, we discuss how nitrogen isotopic analysis could be used for the identification and quantification of the vertical transport processes.

A Simple Theory on the Dynamical Effects of a Stratified Fluid Core upon Nutational Motion of the Earth

Abstract: The theory of Molodensky (1961) on dynamical effects of a stratified fluid outer core upon nutations and diurnal Earth tides is reconstructed on a new and probably much simpler ground. A theory equivalent to Molodensky’s is well represented on the basis of two linear equations for angular-momentum balance of the whole Earth and the fluid outer core, which differ from the well-known equations of Poincare (1910) only in the existence of products of inertia due to deformations of the whole Earth and fluid outer core. The products of inertia are characterized by four parameters which are easily computed for every Earth model by the usual Earth tide equations. A reciprocity relation exists between two of the parameters. The Adams-Wiliamson condition is not a necessary premise of the theory. Amplitudes of nutations and tidal gravity factors are computed for three Earth models. A dissipative core-mantle coupling is introduced into the theory qualitatively. The resulting equations are expressed in the same form as those of Sasao, Okamoto and Sakai (1977). Formulae for secular changes in the Earth-Moon system due to the core-mantle friction are derived as evidences of internal consistency of the theory.

Three-dimensional development of cascade showers induced by 50-, 100-, and 300-GeV electrons

Abstract: Five emulsion chambers were analyzed with two different dilution factors exposed to the 50-, 100-, and 300-GeV electron beams at Fermi National Accelerator Laboratory. The longitudinal development and lateral distribution of the number of shower tracks within a certain radius (\ensuremath{\le} 100 \ensuremath{\mu} m) both roughly agree with the theoretical transition and lateral curves by Nishimura and Kidd connected by a spacing factor equal to the dilution factor. The error of the cascade energy measurement by the conventional way, using the transition curves within a radius 50 \ensuremath{\mu} m, is 18-28% for 50-100 GeV and 13-14% for 300 GeV. Track length within a cylinder of the same radius gives less ambiguity than the above method, when the track length is summed up till the depth is greater than 1.4 times the depth of the maximum number of shower tracks within a radius 50 \ensuremath{\mu} m. Other results with details are also described.

Effects of Interactions on Non-Metallic Behaviors in Two-Dimensional Disordered Systems

Abstract: It is shown that the mutual interactions in the presence of impurity scattering leads to ln T term not only in the conductivity but also in the imaginary part of the self-energy function of two-dimensional electrons gas. Thus the prefactor of ln T term in the conductivity is not universal but depends on the strength of interactions.

Radon Anomaly: A Possible Precursor of the 1978 Izu-Oshima-kinkai Earthquake.

Abstract: Precursory changes in the radon concentration of groundwater were observed prior to the Izu-Oshima-kinkai earthquake (magnitude 7.0) 14 January 1978. The distance from the epicenter to a continuous radon-monitoring station at Nakaizu was about 25 kilometers. A sudden drop and a subsequent increase in the radon concentration recorded on 9 January 1978 were significant. The size of the spike-like change was about 15 percent. After the earthquake, a remarkable increase in the radon concentration occurred.