Showing papers by "Nagoya University published in 1982"

Creation of lattice defects by electronic excitation in alkali halides

Abstract: The main purpose of this article is to review our understanding of the predominant mechanism for defect creation in alkali halides i.e. the evolution of Frenkel (F-H) pairs from self-trapped excitons. Consideration is first given to other models of defect formation since they may play a secondary role in alkali halides and major roles in other solids. Recent experimental work is surveyed with emphasis on studies of non-radiative transitions from highly-excited self-trapped excitons, of F-centre formation and of the photochemical processes associated with impurities and with the surfaces of alkali halides. Brief descriptions are given of the photochemical process in silver halides and of recombination-induced defect migration in compound semiconductors. Finally a critical assessment is made of our understanding of the dominant mechanisms for defect formation in alkali halides with particular attention paid to the identification of the precursor state, the excited state of the self-trapped exciton ...

Relation of adenoma to carcinoma in the gallbladder.

Abstract: In order to clarify the relation of adenoma to carcinoma in the gallbladder, histopathologic examination was made on surgical specimens of 1605 cholecystectomies. Among them, 11 benign adenomas, seven adenomas with malignant change, and 79 invasive carcinomas were found. All of the benign adenomas were 12 mm or less in diameter (average diameter, 5.5 +/- 3.1 mm), while the adenomas having cancerous foci were 12 mm or more in diameter (average diameter, 17.6 +/- 4.4 mm). Most invasive carcinomas were more than 30 mm in diameter. The average patient age was 50.5 +/- 16.3 years for benign adenomas, 58.3 +/- 12.6 years for adenomas with malignant change, and 64.8 +/- 9.6 years for invasive carcinomas. Transition of benign adenoma into carcinoma was histologically traceable. Adenomatous residue was found in 15 (19.0%) of 79 cases of invasive carcinoma.

Primary structure of the ompF gene that codes for a major outer membrane protein of Escherichia coli K-12

Abstract: The nucleotide sequence of the ompF gene coding for a major outer membrane protein of Escherichia coli K-12 has been determined and the amino acid sequence of the OmpF protein was deduced from it. The OmpF protein contains 340 amino acid residues, and is produced from a precursor having 22 extra amino acid residues, the signal peptide, at the amino terminus. The expected secondary structure of the OmpF protein had a high beta-sheet content with a low alpha-helix content. The promoter region and the transcription termination region of the ompF gene had a significantly high AT content, while the AT content of the coding region was about the same as the average AT content of the E. coli chromosome. Following the termination codon, a typical rho-independent transcription termination signal was observed. The codon usage in the ompF gene was highly nonrandom; the codons preferably utilized are those recognized by the most abundant species of isoaccepting tRNAs or those, among synonymous codons recognized by the same tRNA, that can interact more properly with the anticodon.

Local and Overall Buckling of Welded Box Columns

Abstract: An experimental study is presented on the local and overall interaction buckling strength of welded built-up box columns made of high strength steel. A total of twenty-seven box columns with large width-thickness ratios were tested to failure, of which twenty-four columns were centrally loaded and the rest eccentrically loaded. Based on the test results, an empirical design formula is presented to predict the interaction buckling strength. Further, a discussion of an economical way of proportioning box sections is presented.

Mathematical Structures of Line Drawings of Polyhedrons-Toward Man-Machine Communication by Means of Line Drawings

Abstract: Mathematical structures of line drawings of polyhedrons are studied and practical as well as theoretical solutions are obtained for several fundamental problems aroused in scene analysis and in man-machine communication. First, a necessary and sufficient condition for a line drawing to correctly represent a polyhedron is obtained in terms of linear algebra. Next, combinatorial structures are investigated and practical solutions are obtained to such problems as how to discriminate between correct and incorrect line drawings and how to correct vertex-position errors in incorrect line drawings. Lastly, distribution of the degree of freedom of a line drawing is elucidated and a method is proposed for interactive reconstruction of a polyhedron from a line drawing. The results obtained here enable us to make manmachine communication more ``flexible'' in the sense that a machine can reconstruct three-dimensional objects from hand-drawn pictures even if the pictures are not perfect.

The sphere—rod transition of micelles and the two-step micellization of dodecyltrimethylammonium bromide in aqueous NaBr solutions

Abstract: Light scattering was measured on aqueous NaBr solutions of dodecyltrimethylammonium bromide in the presence of 100 to 400 M NaBr, and these results are discussed together with the previous data at lower NaBr concentrations When the NaBr concentration is lower than 18 M , spherical micelles alone are formed At 200 and 300 M NaBr, the first and second critical micelle concentrations (CMC) exist, but at 400 M NaBr they coincide with each other The primary micelle formed above the first CMC has the molecular weight about 23,500–24,400 in 100–400 M NaBr and is spherical The secondary micelle formed above the second CMC has the molecular weight about 29,000–57,500 in 200–400 M NaBr, and its shape would be rodlike Combined with the previous data at lower NaBr concentrations, it is found that a linear Corrin-Harkins relation holds for the first CMC up to 300 M NaBr, and that a linear double logarithmic relation between molecular weight and ionic strength holds for the spherical micelles Another linear double logarithmic relation between molecular weight and ionic strength holds for rodlike micelles The sphere-rod conversion of ionic micelles appears as a sharp transition with respect to the salt concentration, while it occurs as a chemical equilibrium with respect to the surfactant concentration The sphere-rod transition of dodecyltrimethylammonium micelles induced by the change in counterion species from Cl − to Br − means that such a transition of ionic micelles is caused by the counterion binding, which reduces the electrostatic repulsion among charged head groups

Coupling function between solar wind parameters and geomagnetic indices

Abstract: Results of past studies on the correlation of a function of solar wind parameters with a geomagnetic index are reviewed and examined to identify the most relevant coupling function among those hitherto proposed. For the AL index, three functions, BsV, BsV², and Akasofu's e, are compared, where Bs is the southward component of the interplanetary magnetic field and V is the solar wind velocity, and the importance of BsV² is then confirmed by a new presentation of the prediction of each function and the AL index. For the Dst index, validities of the above three functions are also compared, but a new function, BsVP1/3, where P is the dynamic pressure of the solar wind, is proposed as the one that surpasses all of the other three functions in predicting Dst. Implications of the two coupling functions are discussed, and possible directions for future work on this problem are suggested.

Triassic bedded cherts in central Japan are not pelagic

Abstract: Although the origin of bedded radiolarian cherts in orogenic belts has been widely debated1–15, their geochemistry is still poorly understood. Triassic bedded radiolarian cherts occur extensively in the Japanese Islands and are generally not associated with ophiolitic rocks but rather with clastic rocks. We present here chemical data on the Triassic bedded cherts of Kamiaso in central Japan. The relationship of SiO2 with Al2O3, TiO2 and Zr shows that the bedded cherts have been formed by a simple mixing of biogenic silica derived from radiolarians and sponge spicules with lithogenic materials. The ratios of several elements relative to TiO2 strongly suggest that the shale partings and lithogenic portions of the cherts are consanguineous. Sedimentary structures as well as the geochemical evidence suggest that most Kamiaso cherts are turbidity current deposits. Our geochemical and geological data compared with those of recent marine sediments from various environments, demonstrate that the Triassic cherts and associated shale partings are not deep pelagic in origin but formed in an offshore or marginal sea environment.

Calorimetric study on thermal denaturation of lysozyme in polyol-water mixtures.

Abstract: In order to clarify the mechanism of polyol-induced stabilization of protein, the thermal denaturation of lysozyme was studied at pH 4 in aqueous mixtures of some polyols (ethylene glycol, glycerol, erythritol, xylitol, and sorbitol) by a differential scanning calorimetry (DSC). The denaturation temperature, Td, increased with increasing the polyol concentration and the number of hydroxymethyl groups per polyol molecule. The calorimetric enthalpy or denaturation, delta H cal, increased with the increase in polyol concentration, but it was not significantly affected by the chain length of the polyol: delta H cal was about 30 kcal/mol larger in 30% (w/w) aqueous polyols than in water. The standard thermodynamic parameters for denaturation, delta G degrees, delta S degrees, and delta H degrees, which were calculated for glycerol and sorbitol systems using Td and delta H cal and assuming a constant heat capacity change, were an increasing function of polyol concentration. According to the thermodynamics of three component systems, it appeared that one or two polyol molecules are preferentially excluded from the domain of this protein on thermal denaturation. These thermodynamic data support the hypothesis that the thermal stabilization of lysozyme by polyols is due to a preferential solvent interaction effect which strengthens the hydrophobic interaction of the protein.

The peristerite gap in low-grade metamorphic rocks

Abstract: Coexisting Na-plagioclases from greenschists both in the thermal aureole of the Kasugamura Granite, Japan, and in the low-P metamorphic zone of Yap Island, western Pacific were analyzed in great detail; the peristerite solvus was determined for each suite. The asymmetric solvus has steep albite-rich and gentle oligoclase-rich limbs that are similar to those for higher pressure series. The present results together with those from Vermont, New Zealand, and the Sanbagawa belt indicate that the peristerite solvus shifts toward the albite component and higher temperature with increasing pressure. With increasing pressure, albite co-existing with oligoclase (An=100 Ca/Ca+ Na=20) varies in composition from An 8–9 (in Kasugamura), through An 3 (in Yap Island and Vermont), to An 1 (in New Zealand) and An less than 0.5 (in the Sanbagawa belt). The consolute temperatures for the peristerite solvus estimated from available geothermometry are 420° C in Kasugamura, 450–550° C in Vermont and 550°–600° C in the Sanbagawa belt. The variation of plagioclase composition in progressive metamorphic zones is explained by intersection of a plagioclase-forming reaction and the peristerite immiscibility gap in an isobaric T-XAn diagram. The greenschist zone is characterized by albite, the transition zone by occurrence of peristerite pairs and the amphibolite zone by plagioclase of An 20–50.

Cross sections for one-electron capture by highly stripped ions of B, C, N, O, F, Ne, and S from He below 1 keV/amu

Abstract: Cross sections for one-electron transfer from a He atom into the fully stripped, hydrogenlike, heliumlike, and lithiumlike ${\mathrm{B}}^{q+}$, ${\mathrm{C}}^{q+}$, ${\mathrm{N}}^{q+}$, ${\mathrm{O}}^{q+}$, ${\mathrm{F}}^{q\ensuremath{-}}$, ${\mathrm{Ne}}^{q+}$ ions, and also highly stripped ${\mathrm{S}}^{q+}$ ions have been measured at the energy range of $1.5q\ensuremath{-}3.0q$ keV. The measured cross sections are nearly independent of the collision energy with a few exceptions, and most of the cross sections measured are about (1\ensuremath{\sim}4)\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}15}$ ${\mathrm{cm}}^{2}$, but the cross sections for ${\mathrm{B}}^{4+}$, ${\mathrm{C}}^{4+}$, and ${\mathrm{N}}^{4+}$ ions are very small in the energy range studied. When the cross sections measured are plotted as a function of the ionic charge $q$ of isoelectronic projectile ions, strong oscillations in the cross sections are observed. As a first approximation, this oscillatory behavior can be explained in terms of the classical one-electron model.

Mitotic protoplasts and their infection with tobacco mosaic virus RNA encapsulated in liposomes.

Abstract: M-phase and S-phase protoplasts were prepared from tobacco cells in suspension culture after a high degree of synchronization using aphidicolin, a specific inhibitor for eukaryotic DNA polymerase. When TMV-RNA was introduced into these protoplasts mediated by REV liposomes, 37% of M-phase and 26% of S-phase protoplasts were infected as determined by the fluorescent antibody technique. After the 24 hr interval between the introduction of TMV-RNA into protoplasts and the determination of infection, half of the infected mitotic protoplasts formed dumbell-shaped daughter cells. The significance of synchronized protoplasts in genetic engineering of plant cells is discussed in reference to the delivery of DNA into the nucleus.

Spatial Variability of the Undrained Strength of Clays

Abstract: The objective of this study is to provide a simple yet accurate procedure for the description of the spatial variability of the undrained shear strength S u of soft clays. This is achieved on the basis of experimental findings and field observations of the depth-dependent nature of S u . The main features of the method are a linear with depth variation of the mean value and standard deviation of S u and a smooth exponential function that describes the correlation between values received by S u at different vertical locations. The developed procedure is illustrated in a case study involving actual strength data. Two sites are selected from the general area investigated in connection with the West Side Highway in New York City. Each site is characterized by the values of S u obtained along two boreholes using field vane shear tests. The results of the applied analysis verify previous findings on the vertical variability of S u and demonstrates the applicability of the present procedure in the commonly encountered situations with limited data.

Isolation and Characterization of Metabolically Competent Mitochondria from Spinach Leaf Protoplasts

Abstract: Intact mitochondria were prepared from spinach (Spinacia oleracea L. var. Kyoho) leaf protoplasts and purified by Percoll discontinuous gradient centrifugation. Assays of several marker enzymes showed that the final mitochondrial preparations obtained are nearly free from other contaminating organelles, e.g. chloroplasts, peroxisomes, and endoplasmic reticulum. These mitochondria oxidized malate, glycine, succinate, and NADH, tightly coupled to oxidative phosphorylation with high values of ADP to O ratio as well as respiratory control ratio. The rate of NADH oxidation was 331 nmoles O2 per milligram mitochondrial protein per minute, which is comparable to that obtained by highly purified potato or mung bean mitochondria. However, the activity of glutamine synthetase was barely detectable in the isolated mitochondrial fraction. This finding rules out a hypothetical scheme (Jackson, Dench, Morris, Lui, Hall, Moore 1971 Biochem Soc Trans 7: 1122) dealing with the role of the mitochondrial glutamine synthetase in the reassimilation of NH3, which is released during the step of photorespiratory glycine decarboxylation in green leaf tissues, but it is consistent with the photosynthetic nitrogen cycle (Keys, Bird, Cornelius, Lea, Wallsgrove, Miflin 1978 Nature (Lond) 275: 741), in which NH3 reassimilation occurs outside the mitochondria.

On some quasilinear wave equations with dissipative terms

Abstract: In this paper we consider the initial value problems for the following quasilinear wave equations with dissipative terms with initial conditions where

Nuclear behavior during conjugation and meiosis in the fission yeast schizosaccharomyces pombe

Abstract: The fine structure involved with the nuclear behavior occurring during conjugation and meiosis in the fission yeast Schizasaccharomyees pombe was studied by serial thin sectioning and electron microscopy. A pair of haploid cells conjugated via a cytoplasmic isthmus, where cytoplasmic vesicles accumulated. The fusion of the two nucleii was preceded by the fusion of respective nucleus-associated organelles (NAOs), and the prophase I nucleus, taking an elongated shape with the fused NAO at one end, contained strands of dense linear elements, whose number and distribution were not constant, as seen in the three-dimensional reconstruction of serial sections. The first meiotic division was carried out by the spindle, being a preserved nuclear envelope, in which chromosomal microtubules were found to associate with opposite NAOs connected by the pole-to-pole microtubules. The second meiotic division proceeded almost synchronously in the two separate nuclei, the formation of the forespore membrane beginning at the cytoplasmic side of the differentiated NAO.

Spindle evolution in normal and mentally retarded children: a review.

Abstract: In neonates and infants, sleep-wake parameters indicate characteristic ontogenetic features. Sleep spindle activity also changes with maturation in terms of frequency, amplitude, and amount. For this reason, spindles are one of the useful indices of cerebral function in infants. The literature on the development of spindles in normal and mentally retarded children is reviewed.