[en] The results of fundamental studies on development of a miniature dose meter using a semiconductor applicable for dosimetry in both intracavitary and external radiotherapy are described. Many different instruments have been applied in clinical dosimetry for regional lesions, mostly in phantom studies, e. g. the small sized ionization chamber, the fluoroluminescence glass dose meter and the thermoluminescence dose meter. However, there are considerable problems regarding safety, reproducibility, and simplicity for regional dosimetry of intracavitary lesions, such as genitourinary, gastrointestinal and respiratory malignancies. To overcome these problems, an attempt was made to develop a miniature catheter type detector using a variable capacitance Si-diode for gamma ray dosimetry. The newly developed miniature dose meter using a semiconductor has the following characteristics. As the tip of detector (23mm long and 3mm in diameter) is very small, the apparatus unit is easy to manipulate in the dosimetry of intracavitary lesions. As no voltage is supplied to the detector, there is no danger of electric shock from in vivo studies. A strict linearity existed between the radiation dose rate and the generated voltage even when the range of experimental irradiation dose rate was extremely wide. The sensitivity of the detector was affected by the environmental temperature, but it was easy to correct the sensitivity by applying a special calibration chart to the value derived from a thermister enclosed in the detector. Even with the experimental irradiation of more than 50,000R, no changes in the sensitivity of the detector were observed. Thus, the durability of the apparatus was shown to be excellent. (auth.)

[en] Modal analysis method was developed for the vibration analysis of piping system in nuclear or chemical plants, with finite element theory, and verified by sinusoidal vibration method. The natural vibration equation for pipings was derived with stiffness, attenuation and mass matrices, and eigenvalues are obtained with usual method, then the forced vibration equation for pipings was derived with the same manner, and the special solutions are given by modal method from the eigenvalues of the natural vibration equation. Three simple piping models (one, two and three dimensional) were made, and the natural vibration frequency was measured with forced input from an electrical dynamic shaker and a sound speaker. The experimental values of natural vibration frequency showed good agreement with the results by the analytical method. Therefore the theoretical approach for piping system vibration was proved to be valid. (Iwase, T.)

[en] Results of carbon-13 NMR of the solvent (CDCl₃/TFA) induced and thermally induced helix-coil transition of poly (γ-benzyl L-glutamate) (PBLG) are presented in this paper. Sample of PBLG had the DP of ca.820. Proton-NMR spectra were obtained with a JEOL PS-100 spectrometer, and carbon-13 NMR spectra with the same one equipped with PFT-100 Fourier Transform System. Internal TMS was used as a reference. Trifluoroacetic acid (TFA) was purchased from Tokyo Kasei Co., Ltd., and dentrated chloroform of isotopic purity 99.7% was from Merck. Polypeptide solution was of concentration 15 (w/v) %. The solvent induced helix-coil transition midpoint and the shift difference Δ C/H for each carbon atom were obtained. From the results, carbon atoms can be divided into two classes, such as backbone carbons and side chain carbons, according to their chemical shift and helix-coil transition midpoint. The helix-coil transition midpoint of the side chain carbons is found at 17.0 - 18.0 (v/v) % TFA, which is larger than that of the backbone carbons. This means that side chain takes helical conformation before backbone does. The thermally induced helix-coil transition midpoint and the shift difference Δ C/H were also obtained. The shift difference of the backbone carbons is the same as that of the solvent induced helix-coil transition. That of the side chain carbons is smaller than that found in the solvent induced helix-coil transition. The helix-coil transition midpoint of Csub(α)(46.0⁰C) is different from that of C = Osub(Amide) (50.5⁰C). This difference shows existence of the intermediate state which is between α-helix and random coil, and is free from intramolecular hydrogen-bonding. The carbon-13 helix-coil transition midpoint, in particular Csub(α), is different from proton one (α-CH 60.0⁰C). (Kato, T.)

[en] It is very interesting to measure the spin-lattice relaxation time of each carbon-13 in polymer molecules, because the molecular motion of individual groups can be quantitatively estimated separately. The proton-decoupled NMR spectrum of carbon-13 is rather simple to analyze due to a wide range of chemical shift and the absence of complex spin-spin coupling. It has been confirmed that the NMR spin-lattice relaxation mechanism of the carbon-13 in polymers in solution is dipole-dipole interaction. In the present study, the analysis of the transition mechanism of polystyrene in toluene solution was attempted around 55⁰ C, on the basis of the model of molecular motion deduced from the NMR spin-lattice relaxation time of carbon-13. Isotactic polystyrene and atactic polystyrene were used, and measurement was made on the solutions with concentration of 15 wt/v% in the temperature range from 25 to 90⁰ C. The NMR spectra of carbon-13 were measured with a JEOL PS-100 spectrometer. The spin-lattice relaxation time of methine, methylene and C₄ in isotactic polystyrene increased linearly with temperature rise, while that of C₂ and C₃ in i-PS showed bent straight lines, the slope of which was small at low temperature and large at high temperature. The temperature dependence of the spin-lattice relaxation time of atactic poly-styrene was qualitatively similar to that of i-PS. The molecular motion of polystyrene may be divided into skeletal motion, the rotation of side chain and the vibration of C₁-C₄ axis. (Kako, I.)

[en] Changes of the fracture mechanics properties corresponding to the thermal stress cracking of two carbons during the graphitizing heat treatment process are studied by the disk testing methods. Using the baked disk specimens of diameter 30mm and thickness 3mm, the diametral compressive strength, fracture toughness of the mode I. thermal shock resistance and thermal shock fracture toughness are measured at several steps of graphitizing temperature up to 2400₀C in a laboratory furnace. These results are compared with the corresponding values of graphites which were graphitized industrially as a function of temperature. (author)

[en] It is often difficult to establish diagnosis of chronic thyroiditis (Hashimoto's disease) scintigraphically, since the scintigrams take various patterns. In the present paper, the correlation among scintigrams, ¹³¹I-uptake rates and histologic findings were studied on 51 cases of the histologically confirmed chronic thyroiditis. The scintigrams of chronic thyroiditis were classified into the diffuse hypertrophic and the mottled hypertrophic type. The latter was further grouped into three subtypes; those with multidefects, with single defect and with local accumulation. In the diffuse hypertrophic type, histological examination revealed a mild degree of parenchymal degeneration and interstitial fibrosis and the ¹³¹I-uptake rate was usually elevated. In the mottled hypertrophic type, the areas showing the parenchymal degeneration were presented as a defect in the scintigrams, and the ¹³¹I-uptake was variable. Detailed examination of the scintigrams and ¹³¹I-uptake rate might offer useful information for the assessment of the pathophysiology of the chronic thyroiditis. (author)

[en] In the process of visual excitation, a visual pigment, rhodopsin, plays a role of a photoreceptor, and it has been known that the first step in the process is the photoisomerization of the rhodopsin visual chromophore. The bathochromic shift has been regarded as the result of the formation of Schiff base linkage of retinal with opsin. In this study, C-13 NMR spectra were obtained for the analogue of the compound with Schiff base linkage in the visual pigment, and the chemical shift change for going from all trans-retinal to all trans-N-retinylidene-n-butylamine (NRB) was discussed. Further, the effect of N protonation in NRB was examined as the reflection of the function of visual pigment. The compound with Schiff base linkage of all trans-retinal with n-butylamine, namely NRB, was used. The nuclear magnetic resonance (NMR) spectra of carbon-13 Fourier transformation were obtained for this sample at natural abundance with a JNM PS-100 spectrometer. In the C-13 FT NMR spectrum of NRB, besides eight peaks in the C-13 NMR of all trans-retinal, four peaks were observed in higher field region. They originated from the portion of n-butylamine in the compound with Schiff base linkage. The peaks in lower field region were assigned to eleven conjugated polyene carbons by the measurement of spin-lattice relaxation time and shift. The chemical shift change for going from retinal to NRB is shown. It is concluded that the π-electrons in polyene chains are considerably delocalized by the collapse of bond alteration in the retinal forming Schiff base linkage. (Kako, I.)

[en] The effects of retinal and vitamin A on the dynamic structure and stability of hen egg yolk lecithin bilayers have been studied by means of carbon-13 and proton NMR spectroscopies. ₁₃C spin-lattice relaxation and paramagnetic ion permeability studies on lecithin bilayers indicate a marked decrease in flexibility of the lipid acyl chain and a breakdown of membrane impermeableness to ion by the intercalated all-trans- and 11-cis-retinal, whereas the effect of incorporated vitamin A on the fluidity of bilayers is small and its impermeableness to ion remains effective even in the presence of higher concentration of vitamin A. The experimental results are discussed in connection with the mechanism of the permeability change in photoreceptive disk membrane. (author)

[en] A case of lipoma of the spinal cord diagnosed by plain CT scanning was reported, with special reference to pre- and post-operative plain CT findings for lipoma of the spinal cord and the usefulness of plain CT scanning. (Namekawa, K.)

[en] Eighteen renoscintigrams and renograms using ¹²³I-OIH and ^99mTc-DTPA were obtained from 14 patients mainly with drug-induced renal dysfunction by cis-platinum (CDDP). The renoscintigrams and renograms with ¹²³I-OIH or ^99mTc-DTPA of patients with renal dysfunction by CDDP showed the pattern of renal parenchymal dysfunction. The renograms with ^99mTc-DTPA differed from ¹²³I-OIH in severe cases; the 2nd phase disappeared, the curve plateau and we did not get the urinary tracts images in the former. It is more difficult to assess the severity of renal disfunction using ^99mTc-DTPA than ¹²³I-OIH. Therefore, we conclude that ¹²³I-OIH is more useful in monitoring renal function of patients administered CDDP. (author)