Showing papers by "Tohoku University published in 1974"
TL;DR: In this article, the authors explored the mechanism of formation of green rusts, Fe3O4, α-FeOOH, β-FeOH, γ-FeOILH, and amorphous ferric oxyhydroxide in aqueous solution at room temperature.
461 citations
TL;DR: In this article, a large amount of amorphous matter in rust formed in semi-rural atmosphere was identified by infra red and far infra-red spectra as amorphus ferric oxyhydroxide, FeO x (OH) 8-2x.
331 citations
TL;DR: In this article, a novel type of optical fiber which is composed of three portions: the core, inner cladding, and outer cladding was investigated, and it is assumed that the core has the largest refractive index of the three, and the outer claddings index is the next largest.
Abstract: This paper investigates a novel type of optical fiber which is composed of three portions: the core, inner cladding, and outer cladding. It is assumed that the core has the largest refractive index of the three, and the outer cladding index is the next largest. When the index difference between the core and the inner cladding is much larger than that between the outer cladding and the inner, the new fiber has a stronger confinement property than a usual singly clad fiber in the single-mode region. It is also assumed that the inner-cladding thickness is larger than or comparable with the core radius. This confinement is the origin of the following three properties of potential importance in single-mode optical communication. 1) As compared with a singly clad fiber, the largest core area for single-mode operation is roughly twice. 2) The group delay arising from waveguide characteristics has an opposite sign against that of typical glass dispersion. (Singly clad fiber has a dispersion of the same sign.) 3) The field is much more tightly confined within the core as compared with a singly clad fiber. This minimizes extra attenuation due to absorption in the cladding.
239 citations
TL;DR: In this article, an integrated liquidoxide-semiconductor FET structure is described, which is similar to a conventional n-channel depletion mode MOSFET except the gate metal is omitted.
Abstract: An integrated liquid-oxide-semiconductor FET structure is described. The structure is similar to a conventional n-channel depletion mode MOSFET except the gate metal is omitted. Immersing the device in a saline solution, the drain current is controlled by the potential between the source and the solution. Operated as an active recording electrode, the structure has several properties useful in neurological research.
211 citations
TL;DR: In this paper, a coercive force of 6000 Oe, one of the highest reported for isotropic BaFe12O19, was obtained for single-domain coprecipitated powders.
Abstract: Particles of BaFe12O12 were prepared by chemical coprecipitation; their magnetic properties were studied. A coercive force of 6000 Oe, one of the highest reported for isotropic BaFe12O19, was obtained. X-ray and Moessbauer studies were conducted to examine the mechanism of formation. Superparamagnetic α-Fe2O3 was present during synthesis. Ferrites were sintered from these precipitated powders by both the usual method and a hot-press-forging method. The observed magnetic characteristics result from partial orientation of defect-free single-domain coprecipitated powders.
198 citations
189 citations
TL;DR: Ferroelectricity was observed in a lanthanum titanate single crystal (La2Ti2O7), a monoclinic crystal of the space group C22-P21 as mentioned in this paper.
Abstract: Ferroelectricity was observed in a lanthanum titanate single crystal (La2Ti2O7), a monoclinic crystal of the space group C22-P21. The Curie temperature was found to be about 1500°C. It was determined by a D-E hysteresis loop at room temperature that the spontaneous polarization Ps = 5 μC/cm2 and that the coercive field Ec = 45 kV/cm. Ferroelectric domains were observed using a crystal etched by an aqueous solution of nitric acid. The La2Ti2O7crystal showed strong piezoelectric and linear electro-optic effects: electromechanical coupling factor k22 = 0.29; half-wave voltage [E l]δ/2 = 2000 V at a wavelength of 6328 A.
162 citations
TL;DR: To discover the role of the elongation of the micronucleus, called crescent formation, autoradiographic analysis of RNA and DNA synthesis were undertaken using [3H]uridine and [3 H]thymidine.
Abstract: SYNOPSIS
Micronuclear changes of variety 1 of Tetrahymena pyriformis during meiotic prophase have been observed by the light microscope. Morphologic changes in the micronucleus are divided into 6 stages. In stage I, chromatin begins to polarize; in stage II, the micronucleus becomes spindle shaped; and in stage III, one end of the micronucleus protrudes to form a “neck.” In stage IV, where the micronucleus elongates to maximal length, the whole micronucleus consists of 2 chromatin threads pairing longitudinally. One thread probably contains one genome. In stage V, the elongated thread becomes shorter and thicker. Finally, in stage VI, separate chromosomes appear and enter into metaphase.
To discover the role of the elongation of the micronucleus, called crescent formation, autoradiographic analysis of RNA and DNA synthesis were undertaken using [3H]uridine and [3H]thymidine. Pulse label and chase experiments show that the crescent in stages II and III is actively synthesizing RNA. Though no remarkable DNA synthesis was observed during meiosis, a small amount of DNA synthesis occurred during the 1st and 2nd prezygotic divisions.
130 citations
126 citations
TL;DR: Size and weight of prostates were measured in 95 cases by means of transrectal ultrasonotomography and error at this measurement likely to be caused by direction of insertion of the transducer and differences in sonic velocity inside the prostate was confirmed.
Abstract: Size and weight of prostates were measured in 95 cases by means of transrectal ultrasonotomography. The error at this measurement likely to be caused by direction of insertion of the transducer and differences in sonic velocity inside the prostate was originally estimated at 5%. This estimation was later confirmed over 5 cases where radical prostatectomy was performed.
123 citations
TL;DR: Intact tooth enamel of extracted human teeth was exposed to a pulsed Nd-YAG laser at an energy density of 10 to 20 joules/cm2 and a significant difference in solubility was found between laser irradiated and non-irradiated enamel.
Abstract: . Intact tooth enamel of extracted human teeth was exposed to a pulsed Nd-YAG laser at an energy density of 10 to 20 joules/cm2. In vitro demineralization by lactic acid was accomplished by dextran-producing strains of Streptococcus mutatis PK-1 growing on the enamel surface. Scanning electron microscopic observations on the laser irradiated enamel supported micro-radiographic findings and indicated that the laser irradiated enamel surface was more resistant to decalcification than the non-irradiated control enamel. Surface changes suggestive of fusion occurred at the low energy density of 10 to 20 joules/cm2. Laser beam irradiation imparted a degree of alteration to enamel surface that subsequently reduced subsurface demineralization. A significant difference in solubility was found between laser irradiated and non-irradiated enamel.
TL;DR: A new type of equipment for transrectal ultrasonography that has several advantages over the lithotomy position is successfully developed and is described for examination of different intrapelvic organs such as the prostate, the urinary bladder and the uterus.
Abstract: We have successfully developed a new type of equipment for transrectal ultrasonography. The equipment consists of three parts: a transducer assembly, a radial scanner, and a chair. The specially designed transrectal transducer assembly consists of a double tube system; a concave oscillating disc is attached to the rotative inner tube. The top of the transducer tube is covered with a water-filled rubber balloon which is kept in contact with the rectal wall. The chair has a hole over which the anus is positioned and the tube with the radial scanner is introduced into the rectum from below. The angle of the. projecting transducer tube can be shifted freely with a lever. The depth of insertion of the transducer is controlled by the scanner handle. This “sitting posture” procedure has several advantages over the lithotomy position. The diagnostic application of this method is described for examination of different intrapelvic organs such as the prostate, the urinary bladder and the uterus.
TL;DR: Solubilization of the envelope of HVJ (Sendai virus) with alkali-Tween 20 and subsequent fractionation by sucrose density electrofocusing in the presence of Tween 20 resulted in the separation of two biologically distinct glycoproteins, with Morphologically, both fractions consisted of dumbbell-shaped spikes.
TL;DR: In this article, a watersoluble standard acceptor of singlet oxygen for the estimation of tDloJ was found by a kinetic analysis to dyesensitized oxidation of the substrate.
Abstract: INTRODUCTION The determination of quantum yield for singlet oxygen formation (tDloJ in aqueous solution is required for a quantitative interpretation of the photodynamic effect in various biological systems. In condensed media, lAP and '2, singlet oxygen are rapidly quenched by the solvent and have generally very low emission upon photosensitized production. Because of difficulties associated with the spectroscopic methods, it has been necessary to resort to chemical methods to determine generated from various sensitizers (Kearns, 197 1; Politzer ef al., 1971; and Stevens, 1973). The object of the present work was to find a watersoluble standard acceptor of singlet oxygen for the estimation of tDlo, by a kinetic analysis to dyesensitized oxidation of the substrate. It seems that 1 ,4-cycloaddition of singlet oxygen to conjugated diene has the requisite properties because the reaction is presumably not complex. In aqueous solution the best results were obtained with 2,5dimethylfuran as the acceptor, which is the main subject of this note.
TL;DR: Property of the synthesis and cleavage reactions and the exchange of carboxyl group of glycine with bicarbonate are presented and leads to the isolation of a nearly homogeneous form of T-protein but P-protein still is heterogeneous.
TL;DR: Carbon formation by the decomposition of benzene on copper-nickel alloy sheets and powders was studied in this paper in a temperature range from 580 to 900 °C and two types of carbon were observed: one was a flat thin film and the other was a black powder.
TL;DR: In this paper, the p.m. spectra of D -gluco-oligosaccharides and D -glucans in deuterium oxide were studied with respect to the anomeric proton.
TL;DR: In this paper, the theoretical foundation for the concept of the characteristic drying curve is examined by considering the drying out of a porous, non-hygroscopic slab of infinite extent.
TL;DR: The autoxidation rate of native oxymyoglobin estimated at physiological pH and temperature is quite high with t12 ≤ 1.5 days under air saturation, suggesting the existence of an in vivo system immediately reducing metmyoglobin formed to the ferrous state.
TL;DR: In this paper, the existence of the satellite accompanying the 4d 5/2 and 4d 3/2 components is shown by an analysis of the spectra obtained by deconvolution of the raw data of La-halides.
Abstract: X-ray photoemission spectra have been measured of the 4d and 3d shells of La 3+ and Ce 3+ in La- and Ce-halides. The results, particularly in the case of the spectra of the 4d level, show a marked dependence of spectral profile of halogen. The existence of the satellite accompanying the 4d 5/2 and 4d 3/2 components is shown by an analysis of the spectra obtained by deconvolution of the raw data of La-halides. The halogen dependence of the spectra is ascribed to the simultaneous charge transfer transition from the valence level of ligand to the unoccupied 4f level of the metal ion as being the orgin of the satellite.
TL;DR: In this paper, the Czochralski method was used to grow large single crystals of Mg2SiO4 (forsterite) up to 25 mm in maximum diameter and 60 mm long.
TL;DR: The study supports the concept that the cellular inflammatory reaction to influenza virus in mice plays a potentiating part in the development of morbidity and mortality after intranasal virus inoculation.
Abstract: SummaryRepeated injections of rabbit antiserum against mouse thymocytes (ALS) were found to increase the survival rates of mice infected with low doses of influenza A2 virus. Purified immunoglobulin of such rabbit antiserum (ALG) produced the same survival effect without affecting virus growth in lung or serum antibody responses. Lung consolidations of virus infected mice were clearly reduced by ALG administration.The study supports the concept that the cellular inflammatory reaction to influenza virus in mice plays a potentiating part in the development of morbidity and mortality after intranasal virus inoculation.
TL;DR: In this paper, the activation energy for a nickel-catalyzed reaction at 540°C was estimated as 25 kcal/mole, and the reaction occurred in two stages as observed thermogravimetrically.
TL;DR: In this article, the thermolysis of 3,4-dihydro-1-(5methoxybenzocyclobutenyl)-β-carboline hydrochloride in bromobenzene gave the decadehydroyohimbane (19), which on reduction with sodium borohydride afforded the hexadehydroyhimbane(20) which had already been converted into (±)-yohimbone (21) and (±) alloy-obligations (21, 22, 23, 24).
TL;DR: Two protein fractions were isolated from rat liver mitochondria which, when combined, catalyzed the synthesis of glycine from l -serine, ammonia, and bicarbonate and catalyzing the cleavage of glycines and the exchange of the glycine carboxyl group with bic carbonate.
TL;DR: In this article, the boundary condition of lamellar eutectic growth, that the solid-liquid interfaces of two solid phases are isothermal on the average, is considered to constrain the interface too much.
TL;DR: In this article, the effect of milling on the intrinsic coercive force of Ba ferrite powders has been investigated, and it was concluded that lattice defects, rather than superparamagnetic fine particles introduced by milling, greatly affect the intrinsic coerciveness of the powders, and that milling considerably lowers either the nucleation field of the reverse domain or the effective anisotropic field or both.
Abstract: The effect of milling on the intrinsic coercive force of Ba ferrite powders has been ascribed to (1) thermal fluctuations caused by superparamagnetic fine particles and (2) lattice defects introduced by milling. To test these interpretations, the Moessbauer absorption spectra and angular variation of coercive force for ball-milled powders were determined. With increasing milling time, the Moessbauer absorption spectrum becomes ambiguous, and the absorption lines are broadened; the quadrupole-split center line corresponding to superparamagnetic BaFe12O19 cannot be detected. The angular variation of coercive force shows that milling considerably lowers either the nucleation field of the reverse domain or the effective anisotropy field or both. It is concluded that lattice defects, rather than superparamagnetic fine particles introduced by milling, greatly affect the intrinsic coercive force of Ba ferrite powders.