17 alpha,20 alpha-Dihydroxy-4-pregnen-3-one is the naturally occurring spermiation-inducing hormone in the testis of a frog, Rana nigromaculata

Spermiation, the process in which vertebrate spermatozoa are detached from investing Sertoli cells into the lumen of the seminiferous tubule, is a prerequisite for the successful fertilization. Using an in vitro Rana nigromaculata spermiation bioassay, we have shown that gonadotropin initiates spermiation by inducing the synthesis of delta 4-steroids by testis fragments. Among all of the delta 4-steroid metabolites produced by R. nigromaculata testis fragments, spermiation-inducing activity was confined to only one metabolite; this metabolite was identified as 17 alpha,20 alpha-dihydroxy-4-pregnen-3-one (17 alpha,20 alpha-DP). Induction of spermiation by gonadotropin in vitro was accompanied by marked elevations in 17 alpha,20 alpha-DP concentrations in incubation media. These findings provide evidence that 17 alpha,20 alpha-DP is the nautrally occurring spermiation-inducing hormone in R. nigromaculata.     

Diffusion of methyl esters of higher fatty acid in polypropylene

Diffusion coefficients of several methyl esters of linear higher fatty acid (C₁₀?C₁₈) into polypropylene (PP) were determined, over the temperature range of 50 to 110°C, using a mass uptake technique. The relations between an amount of mass uptake and t^1/2 were linear within 10 min, indicating Fickian diffusion. The diffusion coefficients were in the range of 4.6×10^?8 to 6.2×10^?12 cm² sec^?1, increased with temperature, and decreased with increasing n-alkyl chain length of fatty acid. The plots of In D vs. the molecular weight of methyl esters were approximately linear. The temperature dependence of diffusion followed an Arrhenius relationship, and the activation energies were in the range of 133 ? 147 KJ mol^?1 and increased with an increase in n-alkyl chain length of corresponding fatty acid. The diffusion coefficients were discussed with the interaction between methyl esters of higher fatty acid and PP. The diffusion coefficients of methyl esters, at the simultaneous diffusion process, were always higher than that derived from the single diffusion process, except for methyl decanoate with lower molecular weight. The difference in diffusion coefficients in single and simultaneous diffusion was discussed thermodynamically. © 1994 John Wiley & Sons, Inc.     

Evaluation of aseismic integrity in HTTR core-bottom structure III. Structural integrity of core support post component

Component testing of the core support post for the high temperature engineering test reactor (HTTR) was carried out to verify its structural integrity using full-scale and -scale models. The compressive fracture load was measured at room temperature under the conditions of post inclination up to about 1 degree, cyclic load up to 200 times and oxidation up to about 30% of oxidation weight-loss.In this paper, the effects of post inclination angle, cyclic load and oxidation weight-loss of this component on the compressive fracture load were discussed and the fracture load was compared with the design load of the HTTR.     

Quinine Actinometry as a Method for Calibrating Ultraviolet Radiation Intensity in Light-Stability Testing of Pharmaceuticals

A collaborative study was carried out by seven different laboratories to evaluate quinine actinometry as a universal, standardized method for calibrating UV radiation intensity from light sources used in light-stability testing of pharmaceutical products. Near UV fluorescent lamps, white fluorescent lamps, metal halide lamps and xenon arc lamps were employed as light sources. The increase in absorbance at 400 nm of aqueous quinine solutions was found to be proportional to the integrated UV energy emitted from the light sources. The linearity observed between absorbance and integrated UV energy indictates that quinine actinometry can be used to measure the intensity of UV radiation at wavelengths around 330 nm. The slopes of regression curves of absorbance vs integrated UV energy varied among the lamps used due to differing spectral distributions. Light degradation of nifedipine, a model photosensitive drug, was studied based on quinine actinometry.     

Spontaneous intracranial hypotension associated with subdural hematoma: diagnostic usefulness of percutaneous subdural tapping and magnetic resonance imaging

A 55-year-old woman presented with headache which was characterized by aggravation in the upright position and relief in recumbency. Although intracranial hypotension syndrome was considered to be the most-likely possible entity, computed tomography (CT) scans demonstrated subdural fluid collections associated with findings reminiscent of transtentorial herniation. Because of these CT features, cerebrospinal fluid pressure measurement by a lumbar puncture was not performed. In stead, as an alternative method, she underwent percutaneous subdural tapping, which failed to obtain spontaneous drainage of liquid haematoma, indicating intracranial hypotension. In addition, gadolinium-enhanced magnetic resonance imaging study performed later supported the diagnosis of spontaneous intracranial hypotension. Thus, the usefulness and safety of percutaneous subdural tapping for the diagnosis of spontaneous intracranial hypotension is stressed.     

Decreased benzodiazepine receptor binding in Machado-Joseph disease

Benzodiazepine receptor binding was assessed in four Japanese men with Machado-Joseph disease. METHODS: The distribution of benzodiazepine receptors was measured by radionuclide imaging (SPECT) after intravenous administration of 123I-iomazenil (Ro 16-0154). RESULTS: SPECT demonstrated decreased binding throughout the cerebral cortex and cerebellum in all patients. Binding potential (receptor concentration x affinity) was diffusely decreased in cerebral cortex, thalamus, striatum and cerebellum compared with control subjects, suggesting that GABAergic function may be decreased globally in these patients. Cerebral blood flow was largely normal, and no cerebral cortical atrophy was evident on MRI. CONCLUSION: Iodine-123-iomazenil SPECT may become a potent method for detecting impairment of the cerebral cortex even before brain perfusion SPECT or MRI can reveal early abnormalities.     

Full-scale plant study on low temperature thermal dechlorination of PCDDs/PCDFs in fly ash

The low temperature thermal dechlorination process is an effective technology of dioxins decomposition in fly ash of municipal solid waste incinerators(MSWI). A full-scale dechlorination process was designed and constructed in Matsudo city, Japan. It was confirmed that PCDDs/PCDFs decomposition ratio was more than 99% with temperature of 350 degrees C and retention time of 1 hour, and thermal dechlorination moved on from PCDDs/PCDFs having more chlorine atoms to those of less chlorine atoms.     

Optical humidity sensing characteristics of composite thin films of hydrolysed nafion-dye with a terminalN-phenyl group

By using composite films of hydrolysed nafion and dyes having cyanine or triphenyl structures and with a terminal N-phenyl group, an optical humidity sensor has been fabricated. In the reflection mode, the optical intensity of the absorption peaks which depend on the used dyes decreases with relative humidity. The raising and recovery times are less than 1 min. In dry air, the alkyl amine group reacted with SO₃H of hydrolysed nafion and formed a proton additive. Sorption of water molecules induces the deprotonation of the quaternized ammonium group.     

Fiber Optic Signal Attenuation by Secondary Ionizing Radiation in Nuclear Environments

Irradiation of optical fiber waveguides by ionizing radiation can cause an increased loss in optical transmission. The effect of the loss has been measured on several commercially available pure silica core boron-doped clad fibers irradiated with thermal neutrons from a nuclear reactor. In the present work, optical absorptions were measured over the 400-1100nm range during the neutron irradiation. We have found that the attenuation of optical transmission by thermal neutrons is caused by defects produced by alpha particles which are produced in boron-neutron reactions.